Power conversion device

Abstract

A power conversion device provided with any one of a converter (21), an inverter (31), and an AC converter, includes: a plurality of current detectors (26, 27, 28, 34, 35, 36) that detect AC currents of a plurality of phases flowing between an AC power source (1) and the power conversion device (100) or between the power conversion device and a load device (4) for each phase; and an abnormality determiner (71, 72) that determines abnormalities of the plurality of current detectors and abnormalities of the AC currents caused by something other than the current detectors, the abnormality determiner including: an AC current detector abnormality determination section that determines abnormalities of current detection values of the plurality of phases detected by the plurality of current detectors; an AC current estimation section that calculates current estimation values of the current detectors based on a determination result of the AC current detector abnormality determination section; and an AC current abnormality determination section that determines abnormalities of the current detection values of the plurality of phases detected by the plurality of current detectors based on an output of the AC current estimation section.

Description

Technical Field

[0001] This invention relates to power conversion devices. Background Technology

[0002] Conventionally, power conversion devices are known that convert AC power into power with variable voltage and frequency. These devices include a current detector that measures the current flowing between the power source and the device, and control the current to a predetermined value. Additionally, the device includes a current detector that measures the current flowing between the device and a load device, and controls the current to a predetermined value.

[0003] Current detectors, which detect the current flowing between the power conversion device and the motor, and current detectors, which detect the current flowing between the power conversion device and the power source, are essential components for controlling the current of the power conversion device. Therefore, malfunctions in the current detectors can lead to instability in system operation, and in the worst case, may cause unplanned system shutdown.

[0004] Furthermore, the electric motors in power conversion devices are essential for driving factory equipment, etc. If the damage to the lining of the stator windings in the motor worsens, short circuits (partial short circuits, layer short circuits, and interlayer short circuits) between adjacent windings will occur due to insulation deterioration. The winding resistance of the phase with the partial short circuit is smaller compared to the winding resistance of other phases, so an excessive current continues to flow in the phase with the partial short circuit.

[0005] If an excessive current continues to flow through a phase where a partial short circuit has occurred, further partial short circuits will occur in that phase due to accelerated insulation degradation, soon leading to burnout or grounding, and the motor may stop. Therefore, it is important to detect the initial stage of a partial short circuit in the motor.

[0006] As a technique for verifying the integrity of a current detector used to detect the current flowing between a power conversion device and a motor, the following method is known.

[0007] For example, Patent Document 1 discloses a method or technique that detects the current of each phase flowing between the power conversion device and the motor, compares the effective value of the current of each phase with the effective value of the current of other phases, and thereby determines the phase that has an abnormality.

[0008] In addition, as a technique for detecting partial short circuits in the stator windings of an electric motor, there are patent documents 2 and 3, for example.

[0009] Patent document 2 discloses the following method and technology: detecting the current of each phase of the motor, calculating the current ratio between each phase, comparing the current ratio between each phase with a reference value, and thereby determining a partial short circuit.

[0010] Patent document 3 discloses the following method and technology: calculating the motor operating state value based on the phase voltage of each phase current of the motor, and determining the interlayer short circuit based on the motor operating state value.

[0011] Existing technical documents

[0012] Patent documents

[0013] Patent Document 1: Japanese Patent No. 3737370

[0014] Patent Document 2: Japanese Patent Application Publication No. 2007-14151

[0015] Patent Document 3: Japanese Patent No. 5462121 Summary of the Invention

[0016] The problem that the invention aims to solve

[0017] The technology described in Patent Document 1 can identify the phase of the current detector that has malfunctioned when a balanced three-phase load is connected. However, in the event of a partial short circuit, a large current flows through the phase with the small load where the partial short circuit occurred, causing the effective values ​​of the three-phase currents to become inconsistent. Therefore, there is a problem that the current detector may be falsely detected as malfunctioning even when it is functioning normally.

[0018] Furthermore, in the technology described in Patent Document 2, a partial short circuit can be detected when the current detector is functioning normally. However, if the current detector malfunctions, the current detection values ​​between phases will be inconsistent even when no partial short circuit has occurred. Therefore, there is a problem that a partial short circuit may be falsely detected when it has not actually occurred.

[0019] Furthermore, in the technology described in Patent Document 3, a partial short circuit can be determined when the current detector is functioning normally. However, if the current detector malfunctions, its detection signal is used for motor control, causing the motor's operating state value to change even when no partial short circuit has occurred. Therefore, there is a problem that a partial short circuit may be falsely detected when it does not actually occur.

[0020] As described above, none of the technologies in Patent Documents 1 to 3 show a technology for distinguishing between an anomaly of the AC current detector and an AC current anomaly caused by factors other than the AC current detector.

[0021] The present invention was made in view of the above circumstances, and its object is to provide a power conversion device that can distinguish between abnormalities in the detection current detector and AC current abnormalities caused by factors other than the current detector.

[0022] Methods for solving problems

[0023] To address the aforementioned issues, the present invention is constituted as follows.

[0024] That is, the power conversion device of the present invention includes at least one of a converter, an inverter, and an AC converter, wherein the converter converts AC to DC, the inverter converts DC to AC, and the AC converter converts AC to AC. The power conversion device is characterized by comprising: a plurality of current detectors for detecting AC current flowing between an AC power source and the power conversion device, or between the power conversion device and a load device, for each phase; and an anomaly detector for determining anomalies in the plurality of current detectors and anomalies in the AC current caused by factors other than the current detectors. The anomaly detector comprises: an AC current detector anomaly determination unit that determines anomalies in the current detection values ​​of the plurality of phases detected by the plurality of current detectors; an AC current estimation unit that calculates an estimated current value of the current detector based on the determination result of the AC current detector anomaly determination unit; and an AC current anomaly determination unit that determines anomalies in the current detection values ​​of the plurality of phases detected by the plurality of current detectors based on the output of the AC current estimation unit.

[0025] In addition, other means are described in the manner of carrying out the invention.

[0026] Invention Effects

[0027] According to the present invention, a power conversion device is provided that can distinguish between abnormalities in the current detector and AC current abnormalities caused by factors other than the current detector. Attached Figure Description

[0028] Figure 1 This diagram illustrates an example of the circuit structure of the power conversion device according to the first embodiment of the present invention, as well as an example of the connection structure with the AC power supply and the motor.

[0029] Figure 2A This is a diagram illustrating a specific structural example of the converter power conversion section of the power conversion device according to the first embodiment of the present invention.

[0030] Figure 2B This is a diagram illustrating a specific structural example of the inverter power conversion section of the power conversion device according to the first embodiment of the present invention.

[0031] Figure 3AThis is a diagram showing the detailed module structure of the converter-side fault detector of the power conversion device according to the first embodiment of the present invention.

[0032] Figure 3B This is a diagram showing the detailed module structure of the inverter-side fault detector of the power conversion device according to the first embodiment of the present invention.

[0033] Figure 4 It means Figure 3B A flowchart illustrating an example of anomaly detection and handling in the inverter-side anomaly detector.

[0034] Figure 5 It means Figure 3A A block diagram detailing an example of an abnormality detection unit for the AC current detector on the converter side.

[0035] Figure 6 It means Figure 3B A block diagram detailing an example of an abnormality detection unit for the AC current detector on the inverter side.

[0036] Figure 7 This is a flowchart illustrating the various processes in the anomaly calculation unit.

[0037] Figure 8 It means Figure 6 The flowchart shows an example of the abnormal judgment process in the abnormal judgment unit of the AC current detector on the inverter side.

[0038] Figure 9 This is a diagram illustrating a structural example of the inverter-side AC current estimation unit in the inverter-side fault detector of the power conversion device according to the first embodiment of the present invention.

[0039] Figure 10 This is a diagram illustrating a second structural example of the inverter-side AC current estimation unit in the inverter-side fault detector of the power conversion device according to the first embodiment of the present invention.

[0040] Figure 11 This is a diagram illustrating an example of the structure of the AC current anomaly detection unit on the inverter side of the power conversion device according to the first embodiment of the present invention.

[0041] Figure 12 It means Figure 11 The flowchart shows an example of the abnormal judgment process in the AC current abnormal judgment unit on the inverter side.

[0042] Figure 13 This is another example of the structure of the AC current anomaly detection unit on the inverter side.

[0043] Figure 14 It means Figure 13The flowchart shows an example of the abnormal judgment process in the abnormal judgment unit of the AC current detector on the inverter side.

[0044] Figure 15 This is a diagram illustrating an example of the structure of the power conversion device according to the second embodiment of the present invention.

[0045] Figure 16 This diagram illustrates an example of a structure that supplies three-phase AC power from an AC power source to a motor that is a three-phase load via an AC-AC power converter.

[0046] Figure 17 This is a diagram illustrating an example of the structure of the AC current detector anomaly detection unit of the power conversion device according to the third embodiment of the present invention.

[0047] Figure 18 This is a diagram illustrating a structural example of the inverter power conversion section of the power conversion device according to the fourth embodiment of the present invention.

[0048] Explanation of reference numerals in the attached figures

[0049] 1. AC power supply

[0050] 100, 101, 102, 103 Power conversion devices

[0051] 2. Converter Unit (Converter)

[0052] 21, 21R, 21S, 21T converter power conversion section

[0053] 22, 23, 32, 33 Smoothing capacitors (capacitors)

[0054] 26, 27, 28, 34, 35, 36 Current detectors

[0055] 3. Inverter Unit (Inverter)

[0056] 31, 31B, 31U, 31V, 31W Inverter Power Conversion Section

[0057] 34B, 35B, 36B Shunt Resistors (Current Detectors)

[0058] 4. Electric motor (load device)

[0059] 40P wiring (wiring)

[0060] 41C wiring (wiring)

[0061] 42 N wiring (wiring)

[0062] 5. Converter Control Device

[0063] 51 DC Voltage Command Generator

[0064] 52 DC Voltage Controller

[0065] 53 Current Controller

[0066] 54 Pulse Generator

[0067] 6. Inverter control unit

[0068] 61 Speed ​​Command Generator

[0069] 62 Speed ​​Controller

[0070] 63 Current Controller

[0071] 64 Pulse Generator

[0072] 71. Converter-side anomaly detector (anomaly detector)

[0073] 72 Inverter-side anomaly detector (anomaly detector)

[0074] 73. Display (Information Display Unit)

[0075] 711 Converter-side AC current detector anomaly detection unit (AC current detector anomaly detection unit)

[0076] 712 Converter-side AC current estimation section (AC current estimation section)

[0077] 713 Converter-side AC current anomaly detection unit (AC current anomaly detection unit)

[0078] 721 Inverter-side AC current detector anomaly detection unit (AC current detector anomaly detection unit)

[0079] 722 Inverter-side AC current estimation section (AC current estimation section)

[0080] 723 Inverter-side AC current anomaly detection unit (AC current anomaly detection unit)

[0081] 731 AC Current Detector Abnormal Judgment Unit

[0082] 7111, 7211 Adders, First Adder Section

[0083] 7115C and 7215C adders, second adder section

[0084] 7115, 7215 Adders, Third Adder Section

[0085] 7112R, 7112S, 7112T, 7212U, 7212V, 7212W Multipliers, First Multiplication Division

[0086] 7114CR, 7114CS, 7114CT, 7214CU, 7214CV, 7214CW multipliers, second multiplication unit

[0087] 7114R, 7114S, 7114T, 7214U, 7214V, 7214W Multipliers, Third Multiplication Division

[0088] 7113R, 7113S, 7113T, 7213U, 7213V, 7213W filters, first filter

[0089] 7116C, 7216C filters, second filter

[0090] 7116, 7216 filters, third filter

[0091] Anomaly Calculation Department (7117, 7217)

[0092] 72175 First Computational Unit

[0093] 7311 Second Arithmetic Division

[0094] 7312 Storage Unit

[0095] 7313 Operational Condition Judgment Department

[0096] 7314 Third Operations Unit

[0097] 7315 Anomaly Detection Department. Detailed Implementation

[0098] Hereinafter, the embodiments for carrying out the present invention (hereinafter referred to as "implementation methods") will be described with appropriate reference to the accompanying drawings.

[0099] Furthermore, the embodiments described below are illustrative of the present invention, and appropriate omissions and simplifications have been made for clarity. Additionally, not all elements and combinations thereof described in the embodiments are necessarily necessary for the solution of the invention. When multiple identical or functionally identical structural elements exist, different subscripts are sometimes used to describe the same reference numerals. Furthermore, when it is not necessary to distinguish these multiple structural elements, subscripts are sometimes omitted in the description.

[0100] First Embodiment: Power Conversion Device

[0101] Reference Figures 1-9 The power conversion device according to the first embodiment of the present invention will be described.

[0102] Furthermore, the following description is not only an explanation of the power conversion device, but also an explanation of the abnormal detection method for the power conversion device.

[0103] Figure 1 This is a diagram showing an example of the circuit structure of the power conversion device 100 according to the first embodiment of the present invention, and an example of the connection structure with the AC power supply 1 and the motor 4.

[0104] exist Figure 1 In the power conversion device 100, there are a converter unit 2, an inverter unit 3, a converter control device 5, and an inverter control device 6.

[0105] The power conversion device 100 receives AC power from the AC power source 1 and outputs the AC power converted by the converter unit 2 and the inverter unit 3 to the motor 4.

[0106] In addition, the power conversion device 100 includes an inverter-side fault detector 71, an inverter-side fault detector 72, and a display 73.

[0107] The converter unit (also called the converter) 2 takes in AC power from the AC power source 1 and converts it into DC power. The inverter unit (also called the inverter) 3 converts the DC power output from the converter unit 2 into AC power with the desired voltage and frequency.

[0108] Furthermore, the converted AC power is used to drive motor 4. Motor 4 is equipped with a speed detector 7. Converter control device 5 controls converter unit 2. Inverter control device 6 controls inverter unit 3.

[0109] Converter Unit 2

[0110] exist Figure 1 In this configuration, the converter unit 2 includes a converter power conversion section 21.

[0111] like Figure 1 As shown, the converter unit 2 includes a converter power conversion section 21 corresponding to the three phases (R phase, S phase, and T phase), a P-line 40, a C-line 41, an N-line 42, a converter P-side smoothing capacitor 22 (smoothing capacitor), a converter N-side smoothing capacitor 23 (smoothing capacitor), a converter P-side DC voltage detector 24, a converter N-side DC voltage detector 25, an R-phase current detector 26, an S-phase current detector 27, and a T-phase current detector 28.

[0112] The U-phase current detector 34, V-phase current detector 35, and W-phase current detector 36 detect the current flowing through the R-phase, S-phase, and T-phase respectively from the AC power supply 1 to the power conversion unit 21 of the converter.

[0113] Furthermore, the specific structure of the converter power conversion unit 21 corresponding to the 3 phases (R phase, S phase, T phase) will be referred to Figure 2A To be described later.

[0114] The converter unit 2 is a so-called 3-level converter that converts the AC power input to the converter power conversion unit 21 into DC power with a positive potential (first potential) level, a neutral point (zero) potential (second potential) level, and a negative potential (third potential) level.

[0115] Positive potential levels are connected via P wiring 40, neutral point potential levels are connected via C wiring 41, and negative potential levels are connected via N wiring 42.

[0116] The smoothing capacitor 22 on the P side of the converter suppresses the DC voltage fluctuations between the P wiring 40 and the C wiring 41.

[0117] The smoothing capacitor 23 on the N side of the converter suppresses the DC voltage fluctuation between the C wiring 41 and the N wiring 42.

[0118] The DC voltage detector 24 on the P side of the converter measures the inter-terminal voltage of the smoothing capacitor 22 on the P side of the converter.

[0119] The DC voltage detector 25 on the N side of the converter measures the inter-terminal voltage of the smoothing capacitor 23 on the N side of the converter.

[0120] Next, the specific structures of the three converter power conversion units 21R, 21S, and 21T that constitute the converter power conversion unit 21 will be described.

[0121] Figure 2A This is a diagram showing a specific structural example of the converter power conversion section 21 of the power conversion device according to the first embodiment of the present invention.

[0122] exist Figure 2A In the circuit, the converter power conversion sections 21R, 21S, and 21T, corresponding to phases R, S, and T respectively, are converters that convert AC to DC through multiple IGBTs (Insulated Gate Bipolar Transistors) and multiple diodes.

[0123] The converter power conversion units 21R, 21S, and 21T convert the three-phase AC power (voltage) into DC power (voltage) respectively, which is supplied to the P line (positive potential) 40, the C line (neutral point potential) 41, and the N line (negative potential) 42.

[0124] In addition, Figure 2AIn the converter power conversion sections 21R, 21S, and 21T, the description of the control circuit that controls the multiple IGBTs constituting the converter is omitted.

[0125] Each converter's power conversion section 21R, 21S, and 21T is composed of four transistors and six diodes, each consisting of an IGBT (Insulated Gate Bipolar Transistor). The four transistors (transistor 1 through transistor 4) are connected in series between P-line 40 and N-line 42.

[0126] A first diode to a fourth transistor are connected in reverse parallel. In the case of a parasitic diode existing inside the first to fourth transistors, the reverse parallel diodes (first diode to fourth diode) can also be used as parasitic diodes.

[0127] The collector of the first transistor is connected to P-line 40. The emitter of the fourth transistor is connected to N-line 42. The fifth and sixth diodes are connected in series, with the cathode of the fifth diode connected to the junction of the first and second transistors. The anode of the sixth diode is connected to the junction of the third and fourth transistors. The junction of the anode of the fifth diode and the cathode of the sixth diode is connected to C-line 41.

[0128] In addition, multiple transistors in the power conversion units 21R, 21S, and 21T of the converter are uniformly controlled by the converter control device 5.

[0129] like Figure 2A As shown, the power line of phase R is connected to the connection point of the second and third transistors of the converter power conversion section 21R.

[0130] The S-phase power line is connected to the connection point of the second and third transistors of the converter power conversion section 21S.

[0131] The T-phase power line is connected to the connection point of the second and third transistors of the converter power conversion section 21T. However, the P-line 40, C-line 41, and N-line 42, which are the DC power lines of the converter power conversion sections 21R, 21S, and 21T, are shared in the converter power conversion sections 21R, 21S, and 21T.

[0132] As described above, the R-phase, S-phase, and T-phase of the three-phase AC power supply 1 are input to the corresponding converter power conversion units 21R, 21S, and 21T, respectively. However, the DC power side converted by the converter power conversion units 21R, 21S, and 21T is shared for use.

[0133] That is, the three-phase AC power (voltage) of phases R, S, and T is converted into a single DC power (voltage). The three converter power conversion units 21R, 21S, and 21T are controlled by the converter control device 5. Figure 1 Unified control.

[0134] In converter unit 2, as described above, there are R-phase current detectors 26, S-phase current detectors 27, and T-phase current detectors 28. These current detectors detect the current flowing through the R-phase, S-phase, and T-phase of the three-phase AC circuit. The current detection value I detected by each current detector 26, 27, and 28 is... R I S I T The signal is input to the converter control device 5 via the converter-side fault detector 71. The voltage detection signals detected by the DC voltage detectors 24 and 25 are input to the converter control device 5.

[0135] Furthermore, the converter control device 5 will be described later.

[0136] Inverter Unit 3

[0137] exist Figure 1 In the inverter unit 3, there is an inverter power conversion section 31.

[0138] like Figure 1 As shown, the inverter unit 3 includes an inverter power conversion section 31 corresponding to the three phases (U phase, V phase, W phase), a P wiring 40, a C wiring 41, an N wiring 42, an inverter P-side smoothing capacitor 32 (smoothing capacitor), an inverter N-side smoothing capacitor 33 (smoothing capacitor), a U-phase current detector 34, a V-phase current detector 35, and a W-phase current detector 36.

[0139] Furthermore, the specific structure of the inverter power conversion unit 31 corresponding to the three phases (U phase, V phase, W phase) will be referred to Figure 2B To be described later.

[0140] Inverter unit 3 is a so-called 3-level inverter that converts DC power at positive potential (first potential), neutral point (zero) potential (second potential), and negative potential (third potential) into AC power for motor 4.

[0141] The positive potential levels of inverter unit 3 and converter unit 2 are connected through P wiring 40, the neutral point potential level is connected through C wiring 41, and the negative potential level is connected through N wiring 42.

[0142] The inverter P-side smoothing capacitor 32 suppresses DC voltage fluctuations between P wiring 40 and C wiring 41.

[0143] The N-side smoothing capacitor 33 of the inverter suppresses the DC voltage fluctuation between the C wiring 41 and the N wiring 42.

[0144] In addition, the U-phase current detector 34, the V-phase current detector 35, and the W-phase current detector 36 detect the current flowing through the U-phase, V-phase, and W-phase of the three phases (U-phase, V-phase, and W-phase) output by the inverter power conversion unit 31.

[0145] Next, the specific structures of the three inverter power conversion units 31R, 31S, and 31T that constitute the inverter power conversion unit 31 will be explained.

[0146] Figure 2B This is a diagram showing a specific structural example of the inverter power conversion section 31 of the power conversion device according to the first embodiment of the present invention.

[0147] exist Figure 2B In the inverter, the U-phase, V-phase, and W-phase inverter power conversion units 31U, 31V, and 31W, which correspond to 1 respectively, are composed of multiple IGBTs (Insulated Gate Bipolar Transistors) and multiple diodes to form an inverter that converts DC to AC.

[0148] Each inverter power conversion unit 31U, 31V, and 31W is composed of four transistors and six diodes made of IGBTs. The structure of the inverter power conversion units 31U, 31V, and 31W, which includes four transistors and six diodes made of IGBTs, is similar to... Figure 2A The converter power conversion units 21R, 21S, and 21T shown have essentially the same structure, each containing four transistors and six diodes. Therefore, repeated descriptions are omitted here.

[0149] In addition, multiple transistors are uniformly controlled by inverter control unit 6.

[0150] The three converter power conversion units 21R, 21S, and 21T generate DC power (voltage) from three-phase AC power (voltage). Conversely, the three inverter power conversion units 31U, 31V, and 31W generate three-phase (U-phase, V-phase, and W-phase) AC power (voltage) from DC power (voltage). Furthermore, the voltage and frequency of the three-phase AC power (voltage) of phases R, S, and T differ from those of phases U, V, and W.

[0151] like Figure 1 As shown, the three inverter power conversion units 31U, 31V and 31W of the inverter power conversion unit 31 are uniformly controlled by the inverter control device 6.

[0152] As described above, the inverter unit 3 is equipped with a U-phase current detector 34, a V-phase current detector 35, and a W-phase current detector 36. These current detectors detect the current flowing through the U-phase, V-phase, and W-phase of the three-phase AC circuit.

[0153] The current detection value I detected by current detectors 34, 35, and 36 U I V I W The signal is input to the inverter control device 6 via the inverter-side fault detector 72. Furthermore, the inverter-side fault detector 72 and the inverter control device 6 will be described later.

[0154] The outputs of the inverter power conversion section 31U, 31V, and 31W are the outputs of the power conversion device 100. The output of the power conversion device 100 is directly connected to the motor 4, which is a three-phase motor.

[0155] Converter Control Device 5

[0156] exist Figure 1 In this configuration, the converter control device 5 is equipped with a DC voltage command generator 51, a DC voltage controller 52, a current controller 53, and a pulse generator 54.

[0157] The DC voltage command generator 51 generates a DC voltage command value representing the voltage value of the DC voltage output from the converter unit 2 and outputs it to the DC voltage controller 52.

[0158] The DC voltage controller 52 is input with the DC voltage command value from the DC voltage command generator 51, the inter-terminal voltage of the smoothing capacitor 22 on the P side of the converter detected by the DC voltage detector 24, and the inter-terminal voltage of the smoothing capacitor 23 on the N side of the converter detected by the DC voltage detector 25.

[0159] The DC voltage controller 52 calculates the converter output current command value based on the DC voltage command value from the DC voltage command generator 51 and the inter-terminal voltage values ​​from the DC voltage detectors 24 and 25, and outputs the calculation result to the current controller 53. Specifically, the DC voltage controller 52 calculates the converter output current command value in such a way that the sum of the detected DC voltage values ​​input from the DC voltage detectors 24 and 25 is consistent with the DC voltage command value.

[0160] The converter-side fault detector 71 inputs the converter output current command value from the DC voltage controller 52 and the current detection value I detected by the current detectors 26, 27, and 28 to the current controller 53. R I S I T Estimated value I RH ISH I TH .

[0161] The current controller 53 calculates the converter voltage command value in such a way that the estimated value of the current detection value corresponding to the converter output current output from the current detectors 26, 27, 28 is consistent with the converter output current command value input from the DC voltage controller 52, and outputs the converter voltage command value to the pulse generator 54.

[0162] The pulse generator 54 generates pulse signals for controlling the on / off switching of each switching element of the converter power conversion section 21R, 21S, and 21T based on the input converter voltage command value, and outputs the generated pulse signals to the converter power conversion section 21.

[0163] Specifically, the pulse generator 54 generates a pulse signal for switching on and off control in such a way that the output voltage of the converter power conversion units 21R, 21S, and 21T matches the converter output voltage command value input from the current controller 53.

[0164] As described above, the converter control device 5 performs the various calculations and processing described above in the converter unit 2, so that the DC power converted from AC power becomes the desired value, and outputs signals to control the converter power conversion units 21R, 21S, and 21T.

[0165] Inverter Control Unit 6

[0166] exist Figure 1 In the inverter control device 6, there are speed command generator 61, speed controller 62, current controller 63 and pulse generator 64.

[0167] The speed command generator 61 outputs a speed command value to the speed controller 62, which represents the speed at which the motor 4 operates.

[0168] The speed command value from the speed command generator 61 and the speed detection value of the motor 4 detected by the speed detector 7 are input to the speed controller 62.

[0169] The speed controller 62 calculates the inverter output current command value in such a way that the speed detection value input from the speed detector 7 attached to the motor 4 is consistent with the speed command value input from the speed command generator 61, and outputs the inverter output current command value to the current controller 63.

[0170] The inverter output current detection values ​​(current detection value I) from current detectors 34, 35, and 36 are input to the current controller 63. U I V I WEstimated value I RH I SH I TH The inverter output current command value from the speed controller 62 is used to detect the output current of the three-phase AC circuit input from the inverter-side fault detector 72.

[0171] The current controller 63 enables the inverter to output current detection value I. U I V I W Estimated value I RH I SH I TH The inverter voltage command value is calculated in the same manner as the inverter output current command value. Then, the inverter voltage command value is output to the pulse generator 64.

[0172] The pulse generator 64 generates pulse signals for controlling the on / off switching of each switching element of the inverter power conversion section 31U, 31V, and 31W based on the input inverter output voltage command value.

[0173] Specifically, the pulse generator 64 generates a pulse signal for on / off control in such a way that the output voltage of the inverter power conversion unit 31 is consistent with the inverter output voltage command value input from the current controller 63.

[0174] As described above, the inverter control device 6 controls the inverter power conversion units 31U, 31V, and 31W in the inverter unit 3 so that the output torque and speed of the motor 4 meet the desired characteristics.

[0175] <Structure related to anomaly detection in power conversion device 100>

[0176] exist Figure 1 In this device, as a structure related to anomaly detection, the power conversion device 100 includes a converter-side anomaly detector 71, an inverter-side anomaly detector 72, and a display 73.

[0177] The output signals of the converter-side fault detector 71 and the inverter-side fault detector 72 are input to the display 73.

[0178] The display 73 is composed of a display device capable of displaying information, such as a liquid crystal display, and displays the judgment information of the converter-side fault detector 71 and the inverter-side fault detector 72, as well as various other information.

[0179] Although detailed descriptions follow, the converter-side anomaly detector 71 is based on the current detection values ​​I input from the three-phase AC current detectors 26, 27, and 28 of phases R, S, and T. R IS I T To determine whether there are any abnormalities in current detectors 26, 27, 28 and AC currents caused by factors other than current detectors 26, 27, 28 (e.g., AC power supply 1).

[0180] In addition, the inverter-side fault detector 72 is based on the current detection value I input from the three-phase AC current detectors 34, 35, and 36 of phase U, phase V, and phase W. U I V I W To determine whether there are any abnormalities in current detectors 34, 35, and 36, as well as in AC currents caused by factors other than current detectors 34, 35, and 36 (such as motor 4).

[0181] Furthermore, the processing of the converter-side fault detector 71 and the inverter-side fault detector 72 is configured, for example, by executing a program stored in memory using a processor (not shown).

[0182] Converter-side anomaly detector 71

[0183] Figure 3A This is a diagram showing the detailed module structure of the converter-side fault detector 71 of the power conversion device according to the first embodiment of the present invention.

[0184] exist Figure 3A In the converter-side anomaly detector 71, there are a converter-side AC current detector anomaly detection unit 711, a converter-side AC current estimation unit 712, and a converter-side AC current anomaly detection unit 713.

[0185] The current detection values ​​I detected by the R-phase current detector 26, S-phase current detector 27, and T-phase current detector 28 respectively R I S I T The current is input to the AC current detector anomaly judgment unit 711 on the converter side and the AC current estimation unit 712 on the converter side, respectively.

[0186] The converter-side AC current detector anomaly judgment unit 711 diagnoses anomalies in the R-phase current detector 26, S-phase current detector 27, and T-phase current detector 28. Then, it outputs the anomaly information of the current detectors to the converter-side AC current estimation unit 712 and the display 73.

[0187] The converter-side AC current estimation unit 712 is based on the current detection value I. R I S I T Based on the abnormal information from the current detector input from the AC current detector abnormality judgment unit 711 on the converter side, the AC current on the converter side is estimated. Then, the estimated AC current value I is...RH I SH I TH The AC current abnormality judgment unit 713 output to the converter side and the converter control device 5 are also included.

[0188] The converter-side AC current anomaly detection unit 713 is based on the AC current estimation value I. RH I SH I TH It detects abnormalities in the alternating current and outputs the results to the display 73.

[0189] Figure 3B This is a diagram showing the detailed module structure of the inverter-side fault detector 72 of the power conversion device according to the first embodiment of the present invention.

[0190] exist Figure 3B In the inverter-side fault detector 72, there are an inverter-side AC current detector fault detection unit 721, an inverter-side AC current estimation unit 722, and an inverter-side AC current fault detection unit 723.

[0191] The current detection values ​​I detected by the U-phase current detector 34, V-phase current detector 35, and W-phase current detector 36 respectively U I V I W The current is input to the inverter-side AC current detector anomaly judgment unit 721 and the inverter-side AC current estimation unit 722, respectively.

[0192] The inverter-side AC current detector anomaly detection unit 721 diagnoses anomalies in the U-phase current detector 34, V-phase current detector 35, and W-phase current detector 36. Then, it outputs the anomaly information of the current detectors to the inverter-side AC current estimation unit 722 and the display 73.

[0193] Inverter-side AC current estimation unit 722 is based on current detection value I U I V I W Based on the abnormal information from the current detector input from the inverter-side AC current detector abnormality judgment unit 721, the inverter-side AC current is estimated. Then, the estimated AC current estimate I is... UH I VH I WH The AC current anomaly detection unit 723 on the inverter side and the inverter control device 6 are output. The AC current anomaly detection unit 723 on the inverter side determines the AC current anomaly based on the AC current estimation value I. UH I VH I WH It detects abnormalities in the alternating current and outputs the results to the display 73.

[0194] Furthermore, the details of the converter-side AC current detector anomaly judgment unit 711, converter-side AC current estimation unit 712, converter-side AC current anomaly judgment unit 713, inverter-side AC current detector anomaly judgment unit 721, inverter-side AC current estimation unit 722, and inverter-side AC current anomaly judgment unit 723 will be described later.

[0195] Monitor 73

[0196] return Figure 1 The display (information display unit) 73 is, for example, a display device capable of displaying information such as a liquid crystal display, and displays information from the converter-side fault detector 71 and the inverter-side fault detector 72, as well as various other information.

[0197] <Abnormal detection and processing in inverter-side abnormal detection unit 72>

[0198] Figure 4 It means Figure 3B A flowchart of an example of the fault detection process in the inverter-side fault detector 72.

[0199] The following is in accordance with Figure 4 The flowchart illustrates the steps for exception detection and handling.

[0200] also, Figure 3A The converter-side fault detector 71 shown is... Figure 3B The inverter-side fault detector 72 shown has a similar structure. Therefore, the following detailed description of each process in the converter-side fault detector 71 and the inverter-side fault detector 72 will be based on the inverter-side fault detector 72.

[0201] Furthermore, although detailed explanations are omitted, the anomaly detection associated with the converter-side anomaly detector 71 can also be explained by replacing current detectors 34-36 with current detectors 26-28, replacing inverter-side AC current detector anomaly detection unit 721, inverter-side AC current estimation unit 722, and inverter-side AC current anomaly detection unit 723 with converter-side AC current detector anomaly detection unit 711, converter-side AC current estimation unit 712, and converter-side AC current anomaly detection unit 713 respectively, replacing inverter control device 6 with converter control device 5, replacing motor 4 with AC power supply 1, and replacing subscripts U, V, and W with R, S, and T.

[0202] Step S101

[0203] exist Figure 4 When the abnormal judgment process in the inverter-side abnormal judgment unit 72 starts, step S101 is entered.

[0204] In step S101, the inverter-side fault detector 72 determines the current detection value I detected by the current detectors 34, 35, and 36. U I V I W Are all values ​​zero?

[0205] If the inverter-side fault detector 72 determines that the current detection value is I U I V I W If all values ​​are zero (yes), proceed to step S102.

[0206] On the other hand, in the current detection value I U I V I W If at least one of the values ​​is not zero (no), proceed from step S101 to step S103.

[0207] Step S102

[0208] If the process proceeds from step S101 to step S102, in step S102, it is determined that there is an abnormality in the inverter power conversion units 31U, 31V, and 31W.

[0209] Then, the inverter-side fault detector 72 outputs a command to the display 73 to display information indicating that there is a fault in the inverter power conversion units 31U, 31V, and 31W (e.g., a display of "Power conversion unit fault").

[0210] If the process in step S102 is completed, proceed to step S113. The process in step S113 will be described later.

[0211] Step S103

[0212] In step S103, the inverter-side fault detector 72 determines the current detection value I output from the current detectors 34, 35, and 36. U I V I W Whether any of them continuously outputs zero (or a value close to zero).

[0213] When the current detection value I is determined in step S103 U I V I W If any one of them is continuously zero (yes), proceed to step S104.

[0214] On the other hand, in step S103, if it is determined to be the current detection value I U I V I WIf none of them are continuously zero (no), proceed to step S105.

[0215] Step S104

[0216] If the determination in step S103 is "yes", for example, it is determined that an abnormality such as a broken wire or slack has occurred in the current detection circuit (wiring for current detection) used by current detectors 34, 35, and 36 for current detection.

[0217] If the process proceeds from step S103 to step S104, in step S104, an instruction is output to the display 73 to display information indicating that there is an abnormality in the current detection circuit (e.g., a display such as "current detection circuit abnormality").

[0218] If the process in step S104 is completed, proceed to step S113. The process in step S113 will be described later.

[0219] Step S105

[0220] In step S105, the inverter-side fault detector 72 diagnoses whether there is a fault in the current detector.

[0221] For details regarding an example of the anomaly detection method for the current detector in step S105, please refer to... Figures 5-8 To be described later.

[0222] If the inverter-side fault detector 72 determines that the current detectors 34, 35, and 36 are all normal (yes), it proceeds to step S110.

[0223] On the other hand, if at least one of the current detectors 34, 35, and 36 is determined to be abnormal (no), proceed from step S105 to step S106.

[0224] Step S106

[0225] When proceeding from step S105 to step S106, the inverter-side fault detector 72 switches the current detection value to the current estimate value in a way that eliminates the influence of the current detector fault, and waits for a predetermined time.

[0226] Then, after a predetermined time has elapsed, proceed to step S107.

[0227] Furthermore, for details regarding step S106, use... Figures 9-10 To be described later.

[0228] Step S107

[0229] In step S107, the inverter-side fault detector 72 uses the estimated current value, which was used to switch the operation in a manner that excludes the influence of current detector faults, to diagnose whether the current phase difference is within a predetermined range.

[0230] Detailed information regarding an example of a method for detecting current phase difference, using... Figures 11-12 To be described later.

[0231] If the inverter-side fault detector 72 determines that the current phase difference is within a predetermined range (yes), it proceeds to step S108.

[0232] On the other hand, if it is determined that the current phase difference is outside the predetermined range (No), proceed from step S107 to step S109.

[0233] In addition, if using Figures 13-14 As will be described later, in step S107, the current amplitude can also be used instead of the current phase difference to diagnose whether the current amplitude is within a predetermined range.

[0234] Step S108

[0235] In step S108, the inverter-side fault detector 72 determines that the current detector is faulty, while the AC current is normal.

[0236] Then, an instruction is output to display 73 to make display 73 show information indicating the judgment (e.g., "Current detector is abnormal and AC current is normal").

[0237] If the process in step S108 is completed, proceed to step S113. The process in step S113 will be described later.

[0238] Step S109

[0239] In step S109, the inverter-side fault detector 72 determines that both the current detector and the AC current are faulty.

[0240] Then, an instruction is output to display 73 to make display 73 show information indicating the judgment (e.g., "Current detector is abnormal and AC current is abnormal").

[0241] If the process in step S109 is completed, proceed to step S113. The process in step S113 will be described later.

[0242] Step S110

[0243] In step S110, the inverter-side fault detector 72 diagnoses whether the current phase difference is within a predetermined range.

[0244] Detailed information regarding an example of a method for detecting current phase difference, using... Figures 11-12 To be described later.

[0245] If the inverter-side fault detector 72 determines that the current phase difference is within a predetermined range (yes), it proceeds to step S111.

[0246] On the other hand, if it is determined that the current phase difference is outside the predetermined range (No), proceed from step S110 to step S111.

[0247] In addition, if using Figures 13-14 As will be described later, in step S110, the current amplitude can also be used instead of the current phase difference to diagnose whether the current amplitude is within a predetermined range.

[0248] Step S111

[0249] In step S111, the inverter-side fault detector 72 determines that the current detector is normal and the AC current is normal, and ends the series of fault judgment and processing procedures (end).

[0250] Furthermore, in this case, display 73 does not show the current detector and the AC current is normal.

[0251] However, if the display 73 is to display information indicating that the current detector and AC current are normal (e.g., "Current detector is normal and AC current is normal"), a display command can also be output to the display 73.

[0252] Step S112

[0253] In step S112, the inverter-side fault detector 72 outputs a command to make the display 73 display information indicating that the current detector is normal and the AC current is abnormal (e.g., a display such as "current detector is normal and AC current is abnormal").

[0254] If the processing in step S112 is completed, proceed to step S113.

[0255] Step S113

[0256] In step S113, the subsequent steps S102, S104, S108, S109, and S112 are accepted, and the next processing is performed.

[0257] In step S113, the inverter-side fault detector 72 outputs an instruction to the display 73 to display information urging the user to perform an inspection (e.g., "Please check the faulty part and replace it").

[0258] Then, the series of exception handling and detection processes are completed (end).

[0259] <Supplementary Explanation Regarding the Invention Effects of Flowchart Judgment Processing>

[0260] Next, regarding Figure 4 Additional explanation of the effects of the invention's determination process in the flowchart is provided below.

[0261] In the event of an anomaly in at least one of the current detectors 34, 35, and 36, the signal from the anomaly current detector is used to control the inverter control device 6, thus incorporating the effect of the anomaly current detector into the pulse output to the pulse generator 64.

[0262] Therefore, the currents of current detectors 34, 35, and 36 contain the effects of current detector anomalies, making it impossible to distinguish between current detector anomalies and AC current anomalies caused by factors other than the current detectors.

[0263] exist Figure 4 If a current detector malfunction is diagnosed in step S105, an operation switch is performed in step S106 to eliminate the influence of the current detector malfunction. By performing this operation switch, the inverter control device 6 is controlled in a state where the influence of the abnormal current detector signal is eliminated.

[0264] In addition, by switching the operation, the influence of the current detector malfunction is eliminated for the current detectors 34, 35 and 36. Therefore, it is possible to determine in step S107 whether there is an AC current malfunction caused by something other than the current detector.

[0265] <An example of the structure of the converter-side AC current detector anomaly detection unit 711 and the inverter-side AC current detector anomaly detection unit 721 in step S105>

[0266] The converter-side AC current detector anomaly judgment unit 711 and the inverter-side AC current detector anomaly judgment unit 721 preferably utilize Kirchhoff's current law judgment method.

[0267] That is, according to Kirchhoff's current law, the sum of the true values ​​of the three-phase AC current is 0. Therefore, the preferred method is as follows: if the sum of the detected values ​​of the AC current detector is 0, the AC current detector is diagnosed as normal; if it is not 0, the AC current detector is diagnosed as abnormal.

[0268] Next, an example of the AC current detector anomaly judgment unit 711 on the converter side and the AC current detector anomaly judgment unit 721 on the inverter side will be described.

[0269] Converter-side AC current detector anomaly detection unit 711

[0270] Figure 5 It means Figure 3A A block diagram detailing an example of the anomaly detection unit 711 of the AC current detector on the converter side.

[0271] exist Figure 5 In the converter-side AC current detector abnormality judgment unit 711, there are adders 7111 (first adder), multipliers 7112R, 7112S, 7112T (first multiplier), and filters 7113R, 7113S, 7113T (first filters).

[0272] In addition, the AC current detector anomaly judgment unit 711 on the converter side includes multipliers 7114R, 7114S, and 7114T (third multiplication unit), adder 7115 (third adder), and filter 7116 (third filter).

[0273] In addition, the converter-side AC current detector anomaly judgment unit 711 includes multipliers 7114CR, 7114CS, 7114CT (second multiplication unit), adder 7115C (second adder), filter 7116C (second filter) and anomaly calculation unit 7117.

[0274] The current detection value I detected by the R-phase current detector 26 R They are respectively input to adder 7111, multiplier 7112R, 7114R, 7114CT, and 7114CS.

[0275] The current detection value I detected by the S-phase current detector 27 S They are respectively input to adder 7111, multiplier 7112S, 7114S, 7114CT, and 7114CR.

[0276] The current detection value I detected by the T-phase current detector 28 T They are respectively input to adder 7111, multiplier 7112T, 7114T, 7114CR, and 7114CS.

[0277] Adder 7111 calculates the current detection value I. R I S I T The sum of I C0 (=I R +I S +I T The calculated sum I C0 They are respectively input into multipliers 7112R, 7112S, and 7112T.

[0278] The multiplier 7112R calculates the current detection value I. R With the sum of IC0 The product of D R .

[0279] The multiplier 7112S calculates the current detection value I. S With the sum of I C0 The product of D S .

[0280] The multiplier 7112T calculates the current detection value I. T With the sum of I C0 The product of D T .

[0281] The product D output from multipliers 7112R, 7112S, and 7112T R D S D T The filters 7113R, 7113S, and 7113T are input to their respective phase filters.

[0282] Filter 7113R from product D R The product of AC and DC current F is reduced or eliminated. R .

[0283] In addition, the filters 7113R, 7113S, 7113T, 7116 and 7116C in the AC current detector anomaly judgment unit 711 on the converter side reduce or remove the AC component contained in the input signal, but will be referred to as "removed" below.

[0284] Filter 7113S from product D S The product of AC and DC currents F is obtained by removing the AC component. S .

[0285] Filter 7113T from product D T The product of AC and DC currents F is obtained by removing the AC component. T .

[0286] The product of the DC currents F output from filters 7113R, 7113S, and 7113T R F S F T It is input into the anomaly calculation unit 7117.

[0287] The current detection value I is input to the first and second input terminals of the multiplier 7114R, respectively. R The multiplier 7114R outputs the product of these inputs, i.e., the current detection value I. R square I R 2 .

[0288] The current detection value I is input to the first and second input terminals of the multiplier 7114S, respectively. S The multiplier 7114S outputs the product of these inputs, i.e., the current detection value I. S square I S 2 .

[0289] Input the current detection value I to the first and second input terminals of the multiplier 7114T respectively. T The multiplier 7114S outputs the product of these inputs, i.e., the current detection value I. T square I T 2 .

[0290] The square I output from multipliers 7114R, 7114S, and 7114T R 2 I S 2 I T 2 It is input into adder 7115.

[0291] Adder 7115 outputs 3 squared I R 2 I S 2 I T 2 The sum (I R 2 +I S 2 +I T 2 ).

[0292] The output of adder 7115 (I) R 2 +I S 2 +I T 2 The input filter is 7116.

[0293] Filter 7116 from sum (I R 2 +I S 2 +I T 2 Remove the AC component from the sum (I) R 2 +I S 2 +I T 2 The DC component of the current, i.e., the sum of the squared currents, H COutput to the anomaly calculation unit 7117.

[0294] Input current detection value I R I S The multiplier 7114CT outputs their product I R I S .

[0295] Input current detection value I S I T The multiplier 7114CR outputs their product I S I T .

[0296] Input current detection value I T I R The multiplier 7114CS outputs their product I T I R .

[0297] The product I output from multipliers 7114CR, 7114CS, and 7114CT S I T I T I R I R I S They are respectively input into adder 7115C.

[0298] The adder 7115C outputs 3 products I S I T I T I R I R I S The sum (I S I T +I T I R +I R I S ).

[0299] The output of adder 7115C (I S I T +I T I R +I R I S The input is fed into filter 7116C.

[0300] Filter 7116C from sum (I S I T +I T I R +I R I S Remove the AC component from the sum (I) S IT +I T I R +I R I S The DC component of ) is the alternating current product and K C Output to the anomaly calculation unit 7117.

[0301] Anomaly calculation unit 7117 calculates the anomaly based on the sum of various input currents (F). R F S F T H C K C The current detectors 26, 27, and 28 are checked for abnormalities. Furthermore, the detailed description of the comprehensive judgment of abnormalities in the abnormality calculation unit 7117 corresponds to the comprehensive judgment of abnormalities in the abnormality calculation unit 7217 of the inverter-side AC current detector abnormality judgment unit 721 described later, and therefore is also used for the explanation of the comprehensive judgment of abnormalities in the abnormality calculation unit 7217.

[0302] Inverter-side AC current detector anomaly detection unit 721

[0303] Figure 6 It means Figure 3B A block diagram detailing an example of an abnormality detection unit 721 for the inverter-side AC current detector.

[0304] exist Figure 6 In the inverter-side AC current detector abnormality judgment unit 721, there are adder 7211 (first adder), multipliers 7212U, 7212V, 7212W (first multiplier), and filters 7213U, 7213V, 7213W (first filter).

[0305] In addition, the inverter-side AC current detector abnormality judgment unit 721 includes multipliers 7214U, 7214V, and 7214W (third multiplication unit), adder 7215 (third adder), and filter 7216 (third filter).

[0306] In addition, the inverter-side AC current detector anomaly judgment unit 721 includes multipliers 7214CU, 7214CV, 7214CW (second multiplier unit), adder 7215C (second adder unit), filter 7216C (second filter) and anomaly calculation unit 7217.

[0307] The current detection value I detected by the U-phase current detector 34 U They are respectively input to adder 7211 and multipliers 7212U, 7214U, 7214CV, and 7214CW.

[0308] The current detection value I detected by the V-phase current detector 35 V They are respectively input to adder 7211 and multipliers 7212V, 7214V, 7214CW, and 7214CU.

[0309] The current detection value I detected by the W-phase current detector 36 W They are respectively input to adder 7211 and multipliers 7212W, 7214W, 7214CU, and 7214CV.

[0310] Adder 7211 calculates the current detection value I U I V I W The sum of I I0 (=I U +I V +I W The calculated sum I I0 They are respectively input into multipliers 7212U, 7212V, and 7212W.

[0311] The multiplier 7212U calculates the current detection value I. U With the sum of I I0 The product of D U .

[0312] The multiplier 7212V calculates the current detection value I. V With the sum of I I0 The product of D V .

[0313] The 7212W multiplier calculates the current detection value I. W With the sum of I I0 The product of D W .

[0314] The product D output from multipliers 7212U, 7212V, and 7212W U D V D W The filters 7213U, 7213V, and 7213W are input to their respective phases.

[0315] Filter 7213U from product D U The product of AC and DC current F is reduced or eliminated. U Furthermore, the filters 7213U, 7213V, 7213W, 7216, and 7216C in the inverter-side AC current detector anomaly judgment unit 721 reduce or remove the AC component contained in the input signal, but will be referred to as "removed" below.

[0316] Filter 7213V from product D VThe product of AC and DC currents F is obtained by removing the AC component. V .

[0317] Filter 7213W from product D W The product of AC and DC currents F is obtained by removing the AC component. W .

[0318] The product of the DC currents F output from filters 7213U, 7213V, and 7213W U F V F W It is input into the anomaly calculation unit 7217.

[0319] The current detection value I is input to the first and second input terminals of the multiplier 7214U, respectively. U The multiplier 7214U outputs the product of these inputs, i.e., the current detection value I. U square I U 2 .

[0320] Input the current detection value I to the first and second input terminals of the multiplier 7214V respectively. V The multiplier 7214V outputs the product of these inputs, i.e., the current detection value I. V square I V 2 .

[0321] Input the current detection value I to the first and second input terminals of the multiplier 7214W respectively. W The multiplier 7214W outputs the product of these inputs, i.e., the current detection value I. W square I W 2 .

[0322] The squared I output from multipliers 7214U, 7214V, and 7214W U 2 I V 2 I W 2 They are respectively input into adder 7215.

[0323] Adder 7215 outputs 3 squared I U 2 I V 2 I W 2 The sum (I U 2 +I V 2 +I W2 ).

[0324] The output of adder 7215 (I) U 2 +I V 2 +I W 2 The input is fed into filter 7216.

[0325] Filter 7216 from sum (I U 2 +I V 2 +I W 2 Remove the AC component, and sum (I) U 2 +I V 2 +I W 2 The DC component of the current, i.e., the sum of the squared currents, H I Output to the anomaly calculation unit 7217.

[0326] Input current detection value I U I V The multiplier 7214CW outputs the product of these inputs, I. U I V .

[0327] Input current detection value I V I W The multiplier 7214CU outputs the product of these inputs, I. V I W .

[0328] Input current detection value I W I U The multiplier 7214CV outputs the product of these inputs, I. W I U .

[0329] The product I output from multipliers 7214CU, 7214CV, and 7214CW V I W I W I U I U I V They are respectively input into adder 7215C.

[0330] The adder 7215C outputs 3 products I V I W I W I U I U IV The sum (I V I W +I W I U +I U I V ).

[0331] The output of adder 7215C (I V I W +I W I U +I U I V The input is fed into filter 7216C.

[0332] Filter 7216C from sum (I U I V +I V I W +I W I U Remove the AC component, and sum (I) U I V +I V I W +I W I U The DC component of ) is the alternating current product and K I The output is sent to the anomaly calculation unit 7217. The anomaly calculation unit 7217 calculates the value based on the input F. U F V F W H I K I The system determines whether current detectors 34, 35, and 36 are abnormal. Further details regarding the abnormality determination in the abnormality calculation unit 7217 will be described later.

[0333] <Details of the processing in step S105 of the converter-side AC current detector anomaly detection unit 711 and the inverter-side AC current detector anomaly detection unit 721>

[0334] right Figure 5 , Figure 6 The processing of each structure in the converter-side AC current detector anomaly judgment unit 711 and the inverter-side AC current detector anomaly judgment unit 721 shown will be described in detail.

[0335] Current detection values ​​I of current detectors 26, 27, and 28 on the converter side R I S I T The true value of the current I RT I ST I TTThe relationship is expressed by equations (1) to (3). Furthermore, G R G S G T This indicates the detection gain in current detectors 26, 27, and 28.

[0336] I R =I RT ×G R …(1)

[0337] I S =I ST ×G S …(2)

[0338] I T =I TT ×G T …(3)

[0339] Similarly, the current detection values ​​I of the current detectors 34, 35, and 36 on the inverter side... U I V I W The true value of the current I UT I VT I WT The relationship is expressed by equations (4) to (6). Furthermore, G U G V G W This indicates the detection gain in current detectors 34, 35, and 36.

[0340] I U =I UT ×G U …(4)

[0341] I V =I VT ×G V …(5)

[0342] I W =I WT ×G W …(6)

[0343] In addition, regarding the true value I of the actual current flowing through... RT I ST I TT and I UT I VT I WT According to Kirchhoff's current law, equations (7) to (8) hold true.

[0344] I RT +I ST +I TT =0…(7)

[0345] I UT +I VT +I WT =0…(8)

[0346] Explanation of various quantities related to current detectors 34, 35, and 36

[0347] First, before explaining the operation of the anomaly detection in the inverter-side anomaly detector 72, we will explain the various quantities related to the anomalies of the current detectors 34, 35, and 36.

[0348] Figure 5 The converter-side AC current detector anomaly detection unit 711 and shown Figure 6 The inverter-side AC current detector anomaly detection unit 721 shown has a similar structure. Therefore, the following detailed description of each process in the AC current detector anomaly detection units 711 and 721 will be based on the inverter-side AC current detector anomaly detection unit 721.

[0349] Furthermore, although the explanation is omitted, the relationship between the converter-side AC current detector anomaly judgment unit 711 and the inverter-side AC current detector anomaly judgment unit 721 described below can also be explained by replacing the subscripts U, V, and W with R, S, and T.

[0350] True values ​​of currents in phase U, phase V, and phase W (I) UT I VT I WT For example, the waveform of the true current value is a sine wave, and the amplitude of the true current value is I in all three phases. IA When the phase difference of the sinusoidal waveform of the true current of each phase is 2π / 3 (radians), it is represented by the following equations (9) to (11).

[0351] I UT =I IA ×cos(ωt)…(9)

[0352] I VT =I IA ×cos(ωt-2π / 3)…(10)

[0353] I WT =I IA ×cos(ωt-4π / 3)…(11)

[0354] Among them, I IA As mentioned above, the current amplitude is t, which is time, and ω = 2πf is the angular frequency (f is the frequency).

[0355] In addition, according to equations (4) to (6) and (9) to (11), the current detection values ​​I of phase U, phase V, and phase W are... U I V I W It is represented by equations (12) to (14).

[0356] I U =G U I IA ×cos(ωt)…(12)

[0357] I V =G V I IA ×cos(ωt-2π / 3)…(13)

[0358] I W =G W I IA ×cos(ωt-4π / 3)…(14)

[0359] With current detectors 34, 35, and 36 all functioning normally, the detection gain G U G V G W The value is 1, and the detection values ​​I of each current detector 34, 35, and 36 are... U I V I W With truth value I UT I VT I WT equal.

[0360] On the other hand, in the event of an anomaly in current detectors 34, 35, and 36 (e.g., in the event of an abnormality in detection gain), the detection value I... U I V I W With truth value I UT I VT I WT Inconsistent. Therefore, the detection gain G U G V G W The value is a value other than 1 (e.g., 0.9 or 1.1).

[0361] Whether current detectors 34, 35, and 36 are normal or abnormal can be determined by the detection gain G. U G V G W The value is used to determine this.

[0362] Absolute anomaly degree A U A V A W Import >

[0363] Here, the absolute anomaly degree A is imported as information representing the absolute anomaly degree of current detectors 34, 35, and 36. U A V A W .

[0364] [definition]

[0365] Absolute anomaly A U A V A W Defined relative to the detection gain G U G V G W Equations (15) to (17) are valid.

[0366] G U =1+A U …(15)

[0367] G V =1+A V …(16)

[0368] G W =1+A W …(17)

[0369] In absolute anomaly A U A V A W When the value is 0, the corresponding detection gain G U G V G W A value of 1 indicates that current detectors 34, 35, and 36 are functioning normally.

[0370] On the other hand, in absolute anomaly degree A U A V A W For values ​​other than 0, the corresponding detection gain G U G V G W Values ​​other than 1 indicate that current detectors 34, 35, and 36 are malfunctioning.

[0371] Therefore, the absolute anomaly degree A U A V A W These values ​​are information indicating the degree of abnormality, meaning the further away from 0 the abnormality is.

[0372] When using absolute anomaly A U A V A W At that time, the current detection value I shown in equations (12) to (14) above UI V I W It is represented by the following formulas (18) to (20).

[0373] I U =(1+A) U )×I IA ×cos(ωt)…(18)

[0374] I V =(1+A) V )×I IA ×cos(ωt-2π / 3)…(19)

[0375] I W =(1+A) W )×I IA ×cos(ωt-4π / 3)…(20)

[0376] Here, assuming that the U-phase current detector 34, V-phase current detector 35, and W-phase current detector 36 are all functioning normally, G U =G V =G W =1, therefore the following equation (21) holds true.

[0377] G U +G V +G W =3…(21)

[0378] On the other hand, in the event of an anomaly in one of the U-phase current detector 34, V-phase current detector 35, and W-phase current detector 36, due to "G" U ≠1 and G V =G W =1", "G" V ≠1 and G U =G W =1” and “G W ≠1 and G U =G V =1” any one of them, therefore equation (21) does not hold, G U +G V +G W ≠3.

[0379] Additionally, if two or three of the U-phase current detector 34, V-phase current detector 35, and W-phase current detector 36 malfunction, it becomes G. U +G V +G W =3 or G U +G V +G W ≠ any of the 3. Furthermore, G U+G V +G W =3 holds true when the detection gain of the abnormal current detector cancels out the deviation of 1. When the deviations do not cancel each other out, G... U +G V +G W ≠3.

[0380] Relative detection gain G U0 G V0 G W0 Import >

[0381] Here, the newly imported relative detection gain G, whose sum of gains is always 3, is used. U0 G V0 G W0 and variable B I .

[0382] [definition]

[0383] Relative detection gain G U0 G V0 G W0 and variable B I The quantity is defined as a quantity set in such a way as the following equations (22), (23) to (25) hold.

[0384] G U0 +G V0 +G W0 =3…(22)

[0385] I U =G U0 B I ×cos(ωt)…(23)

[0386] I V =G V0 B I ×cos(ωt-2π / 3)…(24)

[0387] I W =G W0 B I ×cos(ωt-4π / 3)…(25)

[0388] Based on the comparison of equations (23) to (25) and equations (12) to (14), the detection gain G U G V G W With relative detection gain G U0 G V0 G W0 Between these points, the following equations (26) to (28) hold true.

[0389] GU0 B I =G U I IA …(26)

[0390] G V0 B I =G V I IA …(27)

[0391] G W0 B I =G W I IA …(28)

[0392] According to equations (26) to (28) and equation (22), variable B I Using detection gain G U G V G W and current amplitude I IA It is represented by the following formula (29).

[0393] B I =(G U +G V +G W )×I IA / (G U0 +G V0 +G W0 )

[0394] =(G U +G V +G W )×I IA / 3…(29)

[0395] Relative Anomaly A U0 A V0 A W0 Import >

[0396] Here, the relative anomaly A of current detectors 34, 35, and 36 is imported. U0 A V0 A W0 .

[0397] [definition]

[0398] Relative anomaly A U0 A V0 A W0 It is defined as a quantity set in such a way as the following equations (30) to (32) hold.

[0399] G U0 =1+A U0 …(30)

[0400] G V0 =1+A V0 …(31)

[0401] G W0 =1+A W0 …(32)

[0402] When using the above relative anomaly A U0 A V0 A W0 When, the above equations (23) to (25) are represented by the following equations (33) to (35).

[0403] I U =(1+A) U0 )×B I ×cos(ωt)…(33)

[0404] I V =(1+A) V0 )×B I ×cos(ωt-2π / 3)…(34)

[0405] I W =(1+A) W0 )×B I ×cos(ωt-4π / 3)…(35)

[0406] Furthermore, according to equation (22) and equations (30) to (32), regarding the relative anomaly degree A U0 A V0 A W0 The sum of these equations makes equation (36) true.

[0407] A U0 +A V0 +A W0 =0…(36)

[0408] Therefore, the relative anomaly degree A U0 A V0 A W0 It can be said that the absolute abnormality degree A, which represents the degree of abnormality, is... U A V A W It is obtained by standardization in accordance with the way that equation (36) holds.

[0409] On the other hand, regarding the absolute anomaly degree A U A V A W With current detectors 34, 35, and 36 all functioning normally (G) U =G V =G W=1), according to equations (15) to (17) and equation (21), it becomes A U +A V +A W =0, but becomes A if more than one of the current detectors 34, 35, and 36 is abnormal. U +A V +A W =0 or A U +A V +A W ≠ any of 0.

[0410] <Operation of the inverter-side AC current detector anomaly detection unit 721>

[0411] As mentioned above, Figure 5 The converter-side AC current detector anomaly detection unit 711 shown is... Figure 6 The inverter-side AC current detector anomaly detection unit 721 shown has a similar structure. Therefore, the operation of the converter-side AC current detector anomaly detection unit 711 and the inverter-side AC current detector anomaly detection unit 721 is as follows: Figure 6 The inverter-side AC current detector anomaly detection unit 721 will be used as an example for explanation.

[0412] Furthermore, the operation of the inverter-side AC current detector anomaly detection unit 721 will be explained below. However, by replacing the subscripts U, V, and W with R, S, and T, the operation of the converter-side AC current detector anomaly detection unit 711 can also be explained in the same way.

[0413] Regarding the current flowing through equations (9) to (11) above, the output I of the inverter-side AC current detector anomaly judgment unit 721 will be explained. I0 D U D V D W F U F V F W I U 2 +I V 2 +I W 2 H I I U I V +I V I W +I W I U and K I .

[0414] Furthermore, in the following explanation, it is assumed that the current detection values ​​in equations (12) to (14) above do not contain a DC component (offset component).

[0415] When the current sensing value contains a DC component (offset component), for example, removing or reducing I can be used. U I V I W A filter (not shown) containing the DC component is used instead of the current detection value I. U I V I W And using removal or reduction of I U I V I W The output of the filter (fourth filter) containing the DC component is not shown.

[0416] First, from Figure 6 The sum of the outputs of the adder 7211 is I I0 (=I U +I V +I W ) is represented by the following formula (37).

[0417] I I0 =I U +I V +I W

[0418] =B I ×(A U0 ×cos(ωt)+A V0 ×cos(ωt-2π / 3)

[0419] +A W0 ×cos(ωt-4π / 3))…(37)

[0420] The outputs D of multipliers 7212U, 7212V, and 7212W U D V D W This is represented by equations (38) to (40). Furthermore, in equations (38) to (40), the symbol √(X) represents X. 1 / 2 The symbol √(X) has the same representation and meaning in other expressions.

[0421] D U =(I U +I V +I W )×I U

[0422] =1 / 2×B I 2 AU0 ×(1+A U0 )×(1+cos(2ωt))

[0423] -1 / 4×B I 2 A V0 ×(1+A U0 )×(1+cos(2ωt)-√(3)×sin(2ωt))

[0424] -1 / 4×B I 2 A W0 ×(1+A U0 )×(1+cos(2ωt)+√(3)×sin(2ωt))…(38)

[0425] D V =(I U +I V +I W )×I V

[0426] =-1 / 4×B I 2 A U0 ×(1+A V0 )×(1+cos(2ωt)-√(3)×sin(2ωt))

[0427] +1 / 2×B I 2 A V0 ×(1+A V0 )×(1+cos(2ωt-4π / 3))

[0428] -1 / 4×B I 2 A W0 ×(1+A V0 )×(1-2×cos(2ωt))…(39)

[0429] D W =(I U +I V +I W )×I W

[0430] =-1 / 4×B I 2 A U0 ×(1+A W0 )×(1+cos(2ωt)+√(3)×sin(2ωt))

[0431] -1 / 4×B I2 A V0 ×(1+A W0 )×(1-2×cos(2ωt))

[0432] +1 / 2×B I 2 A W0 ×(1+A W0 )×(1+cos(2ωt-8π / 3))…(40)

[0433] Filters 7213U, 7213V, and 7213W affect the input D U D V D W Perform filtering to remove the AC components they contain, and output D. U D V D W The DC component, i.e., F U F V F W The filter. Furthermore, according to equations (38) to (40), in an ideal situation without pulsation, the DC component can be output as long as the 2ω component, which is twice the fundamental frequency ω, can be removed. Therefore, the minimum performance required for filters 7213U, 7213V, and 7213W is to remove the 2ω component.

[0434] If we consider D as expressed by equations (38) to (40) U D V D W The AC component is removed by filtering; that is, if the periodic changes of the trigonometric function are removed, the output F of filters 7213U, 7213V, and 7213W will be... U F V F W It is represented by the following formulas (41) to (43).

[0435] F U =1 / 4×B I2 ×(2A U0 -A V0 -A W0 )×(1+A U0 (41)

[0436] F V =1 / 4×B I2 ×(2A V0 -A W0 -A U0 )×(1+A V0 (42)

[0437] F W =1 / 4×BI2 ×(2A W0 -A U0 -A V0 )×(1+A W0 )…(43)

[0438] Furthermore, if we substitute equation (36) into equations (41) to (43) and rearrange, the output F of filters 7213U, 7213V, and 7213W will be... U F V F W It is represented by the following formulas (44) to (46).

[0439] F U =3 / 4×B I 2 A U0 ×(1+A U0 (44)

[0440] F V =3 / 4×B I 2 A V0 ×(1+A V0 (45)

[0441] F W =3 / 4×B I 2 A W0 ×(1+A W0 )…(46)

[0442] The output of adder 7215 (I) U 2 +I V 2 +I W 2 ) is represented by the following formula (47).

[0443] I U 2 +I V 2 +I W 2 =B I 2 ×(1+A U0 ) 2 ×(1+cos(2ωt)) / 2

[0444] +B I 2 ×(1+A V0 ) 2 ×(1+cos(2ωt-4π / 3)) / 2

[0445] +B I 2 ×(1+A W0 ) 2 ×(1+cos(2ωt-8π / 3)) / 2

[0446] …(47)

[0447] Filter 7216 for the input I U 2 +I V 2 +I W 2 Perform filtering to remove the AC components they contain, and output as I. U 2 +I V 2 +I W 2 H of the DC component I .

[0448] If for I represented by the above equation (47) U 2 +I V 2 +I W 2 After performing filtering to remove the AC component, that is, removing the periodic changes of the trigonometric function, the output H of the filter 726 of the second system is... I It is represented by the following equation (48). In addition, the above equation (36) was used in the calculation process.

[0449] H I =3 / 2×B I 2 +1 / 2×B I 2 ×(A U0 2 +A V0 2 +A W0 2 )…(48)

[0450] The output of adder 7215C (I U I V +I V I W +I W I U ) is represented by the following formula (49).

[0451] I U I V +I V I W +I WI U = -1 / 4 × B I 2 ×(1+A U0 )×(1+A V0 )×(1+cos(2ωt)-√(3)×sin(2ωt))

[0452] -1 / 4×B I 2 ×(1+A V0 )×(1+A W0 )×(1+2×cos(2ωt))

[0453] -1 / 4×B I 2 ×(1+A W0 )×(1+A U0 )×(1+cos(2ωt)+√(3)×sin(2ωt))

[0454] …(49)

[0455] The 7216C filter applies the input I... U I V +I V I W +I W I U Perform filtering to remove the AC components they contain, and output as I. U I V +I V I W +I W I U K of the DC component I .

[0456] If for I represented by the above equation (49) U I V +I V I W +I W I U After performing filtering to remove AC components, specifically removing the periodic variations of trigonometric functions, the output K of filter 7216C is... I It is represented by the following equation (50). In addition, the above equation (36) was used in the calculation process.

[0457] K I = -3 / 4 × B I 2 -1 / 4×B I 2 ×(A U0 A V0 +A V0 AW0 +A W0 A U0 )

[0458] …(50)

[0459] <Processing in Anomaly Calculation Unit 7217>

[0460] exist Figure 6 In the anomaly determination process of the anomaly degree calculation unit 7217 of the inverter-side AC current detector anomaly determination unit 721 shown, the standardized anomaly degree calculation value A described below is used. U0C0 A V0C0 A W0C0 .

[0461] Figure 7 This is a block diagram illustrating the various processes in the anomaly calculation unit 7217.

[0462] Anomaly calculation unit 7217 is equipped with the ability to perform and standardize anomaly calculation values ​​A U0C0 A V0C0 A W0C0 The related arithmetic processing units 72171 to 72175.

[0463] The anomaly calculation unit 7217 calculates the DC component F output from filters 7213U, 7213V, 7213W, 7216, and 7216C. U F V F W H I K I Calculate the standardized outlier value A. U0C0 A V0C0 A W0C0 .

[0464] The following will explain the equations (53), (57) to (59) and (61) to (63) represented by the arithmetic units 72171 to 72175.

[0465] Computation Department 72171

[0466] If we use the above formula (36) to rearrange the above with H respectively I The relevant equation (48) and its relation to K I From the relevant equation (50), we get equations (51) and (52).

[0467] 2×H I =3×B I 2 +2×B I 2 ×(A V0 2+A W0 2 +A V0 A W0 (51)

[0468] 8×K I =-6×B I 2 +2×B I 2 ×(A V0 2 +A W0 2 +A V0 A W0 (52)

[0469] According to equations (51) and (52), if the relative anomaly degree A is eliminated... U0 A V0 A W0 Then the following formula (53) holds true.

[0470] B I 2 =(2H I -8K I ) / 9…(53)

[0471] That is, the arithmetic unit 72171 calculates the DC component H input from the filters 7216 and 7216C. I K I B is calculated using equation (53). I 2 .

[0472] Arithmetic Section 72172~72174

[0473] If we rearrange the aforementioned equations (44) to (46) respectively, we obtain the results shown in equations (54) to (56) respectively, which correspond to the relative anomaly degree A. U0 A V0 A W0 The relevant quadratic equation.

[0474] 3B I 2 A U0 2 +3B I 2 A U0 -4F U =0…(54)

[0475] 3B I 2 A V0 2 +3B I2 A V0 -4F V =0…(55)

[0476] 3B I 2 A W0 2 +3B I 2 A W0 -4F W =0…(56)

[0477] If we take the solution obtained by applying the formula for solving a quadratic equation to equations (54) to (56) respectively as A U0C A V0C A W0C Then A U0C A V0C A W0C The following equations (57) to (59) are given.

[0478] A U0C =(-3B) I 2 +√(9B I 4 +48B I 2 F U )) / (6B I 2 )…(57)

[0479] A V0C =(-3B) I 2 +√(9B I 4 +48B I 2 F V )) / (6B I 2 )…(58)

[0480] A W0C =(-3B) I 2 +√(9B I 4 +48B I 2 F W )) / (6B I 2 (59)

[0481] Here, A calculated from equations (57) to (59) will be... U0C A V0C A W0C(Relative anomaly A) U0 A V0 A W0 The calculated value is called the anomaly calculation value.

[0482] As described above (for example, equations (33) to (35)), since the current is assumed to be a sinusoidal current, the anomaly calculation value A calculated by equations (57) to (59) is... U0C A V0C A W0C This indicates the degree of abnormality of phases U, V, and W under ideal conditions without current pulsation.

[0483] exist Figure 7 In the middle, the arithmetic unit 72172 calculates the DC component F input from the filter 7213U. U And B calculated by the arithmetic unit 72171 I 2 The anomaly degree A, representing the degree of anomaly in phase U, is calculated using equation (57). U0C .

[0484] The arithmetic unit 72173 is based on the DC component F V and B I 2 The anomaly degree A, representing the degree of anomaly in phase V, is calculated using equation (58). V0C .

[0485] The arithmetic unit 72174 is based on the DC component F W and B I 2 The anomaly degree A, representing the degree of anomaly in phase W, is calculated using equation (59). W0C .

[0486] Furthermore, in the formulas for the solutions to quadratic equations, the sign before √ is either positive or negative, but it is set to positive in equations (57) to (59). For example, in the case of zero anomaly, the right-hand side of equation (57) must be zero. In the case of zero anomaly, F calculated by equation (44) U It is zero. Assuming the sign before √ in equation (57) is negative, if F... U Substituting 0 into the numerator on the right side of equation (57), we get (-3B) I 2 -√(9B I 4 ), the right side of equation (57) is not zero. On the other hand, if the sign before √ in equation (57) is positive, if F U Substituting 0 into the numerator on the right side of equation (57), we get (-3B) I 2 +√(9BI 4 )), the right side of equation (57) becomes zero.

[0487] <Regarding situations involving partial short circuits and three-phase current imbalance>

[0488] In the calculation of the abnormality and degree of abnormality of current detectors 34, 35, and 36 in the AC current detector abnormality judgment unit 721 on the inverter side, the calculation is performed on the premise of three-phase current balance.

[0489] Therefore, for example, in the case of a partial short circuit caused by increased damage to the stator winding coating in a motor that is a three-phase load, a large amount of current flows through the phase with the small load that has a partial short circuit, and the three-phase current becomes unbalanced.

[0490] As a result, the amplitude of the true current value in equations (9) to (11) is inconsistent in each phase, and the phase difference between each phase in equations (9) to (11) also becomes a value different from 2π / 3 (radians).

[0491] However, if the AC current detector is normal and a three-phase imbalance occurs, and if using Figure 6 The structure of the inverter-side AC current detector abnormality judgment unit 721 shown indicates that the output of the adder 7211 becomes 0.

[0492] Therefore, the output F of filters 7213U, 7213V, and 7213W U F V F W The value of A is 0, calculated from equations (57) to (59). U0C A V0C A W0C It is also 0.

[0493] That is, even if the amplitude of the true current value is inconsistent in each phase, it will not be misdiagnosed as an abnormality of the current detector (AC current detector).

[0494] Furthermore, even in the event of simultaneous AC current detector malfunction and three-phase imbalance, the system, comprising adder 7211, multipliers 7212U, 7212V, 7212W, and filters 7213U, 7213V, and 7213W, can achieve the same performance. Figure 6 The structure of the inverter-side AC current detector anomaly judgment unit 721 reduces the error caused by the three-phase imbalance in the anomaly degree of the current detector calculated by equations (57) to (59).

[0495] Therefore, even if the assumptions in equations (9) to (11) above are incorrect, it is still possible to pass through Figure 6 The structure shown detects anomalies with less error.

[0496] Computation Department 72175

[0497] Figure 7 The input signal of the arithmetic unit 72175 (first arithmetic unit) shown is the anomaly calculation value A. U0C A V0C A W0C This represents the anomaly degree of phases U, V, and W under ideal conditions without current ripple. Therefore, when the current waveform does not contain a ripple component, the calculated anomaly degree value A... U0C A V0C A W0C The sum and relative anomaly A U0 A V0 A W0 The situation is also zero.

[0498] That is, when the current waveform does not contain a pulsating component, A U0C +A V0C +A W0C =0. On the other hand, when the current waveform contains a pulsating component, A U0C +A V0C +A W0C >0.

[0499] Standardized anomaly calculation value A U0C0 A V0C0 A W0C0 Import >

[0500] Therefore, the newly introduced standardized outlier calculation value A makes equation (60) valid. U0C0 A V0C0 A W0C0 .

[0501] [definition]

[0502] Standardized outlier calculation value A U0C0 A V0C0 A W0C0 It is defined as a quantity set in such a way as the following equations (60) to (63) hold.

[0503] A U0C0 +A V0C0 +A W0C0 =0…(60)

[0504] A U0C0 =A U0C -(A U0C +A V0C +A W0C ) / 3…(61)

[0505] AV0C0 =A V0C -(A U0C +A V0C +A W0C ) / 3…(62)

[0506] A W0C0 =A W0C -(A U0C +A V0C +A W0C ) / 3…(63)

[0507] The second term on the right side of each of equations (61) to (63) can be considered as the calculated value A for anomaly degree to satisfy equation (60). U0C A V0C A W0C The correction item.

[0508] Even if the current waveform contains a pulsating component and A U0C +A V0C +A W0C If the value is greater than 0, then the standardized outlier calculation value A... U0C0 A V0C0 A W0C0 Then A U0C0 +A V0C0 +A W0C0 =0 is true.

[0509] Figure 7 The arithmetic unit 72175 (first arithmetic unit) is based on the anomaly calculation value A calculated by the arithmetic units 72172 to 72174. U0C A V0C A W0C The standardized outlier value A is calculated using equations (61) to (63). U0C0 A V0C0 A W0C0 .

[0510] Furthermore, when the current flowing in the current detector has a variable frequency due to reasons such as the variable operating frequency of the motor 4, the inverter-side AC current detector fault detection unit 721 is preferably configured to... Figure 6 The time constant (or cutoff frequency) of the filter used can be varied according to the operating frequency, so that even when the operating frequency of motor 4 is low, the AC component contained in the filter input can be removed to a greater extent.

[0511] Although Figure 1The description is omitted, but the speed command is input from the speed command generator 61 to the inverter-side AC current detector anomaly judgment unit 721 as operating frequency information (speed information). Alternatively, the speed detection value of the motor 4 detected by the speed detector 7 can be used instead of the speed command.

[0512] Alternatively, the filter's time constant can be preset in a way that significantly reduces the AC component contained in the filter input even when operating at low speeds.

[0513] In addition, when the operating frequency of motor 4 is extremely low, the time constant of the filter becomes extremely large, so the abnormal judgment described later can be omitted when the operating frequency of motor 4 is low.

[0514] <Abnormal judgment processing in the abnormal judgment unit 721 of the AC current detector on the inverter side>

[0515] Figure 8 It means Figure 6 The flowchart shows an example of the anomaly detection processing in the anomaly detection unit 721 of the inverter-side AC current detector. Hereinafter, according to... Figure 8 The flowchart illustrates the steps for exception detection and handling.

[0516] Step S1001

[0517] If the abnormal judgment process in the abnormal judgment unit 721 of the inverter-side AC current detector starts, then proceed to step S1001.

[0518] In step S1001, the inverter-side AC current detector anomaly judgment unit 721 performs the calculations of the above-mentioned calculation units 72171 to 72175 to calculate the standardized anomaly degree calculation value A. U0C0 A V0C0 A W0C0 .

[0519] Step S1002

[0520] Step S1002 is the step of determining whether all current detectors 34 to 36 are normal.

[0521] In step S1002, the inverter-side AC current detector anomaly judgment unit 721 calculates the standardized anomaly degree value A. U0C0 A V0C0 A W0C0 Determine |A U0C0 |、|A V0C0 |、|A W0C0 Is the maximum value in | greater than a predetermined value α (e.g., 3%)?

[0522] That is, whether the judgment (64) is true. In addition, MAX(a, b, c) represents the largest value among values ​​a, b, and c.

[0523] MAX(|A U0C0 |,|A V0C0 |,|A W0C0 |)>Specified value α…(64)

[0524] In step S1002, if it is determined that equation (64) is true, then proceed from step S1002 to step S1003.

[0525] On the other hand, if it is determined in step S1002 that equation (64) is not valid (no), that is, in |A U0C0 |、|A V0C0 |、|A W0C0 If all values ​​are below the specified value α, proceed from step S1002 to step S1011.

[0526] Furthermore, the processing in step S1011 will be described later.

[0527] Step S1003

[0528] In step S1003, the inverter-side AC current detector abnormality judgment unit 721 determines whether the following formula (65) is true.

[0529] ([MAX]-2×[MIN]) / [MAX]>Specified value β…(65)

[0530] In equation (65), [MAX] represents MAX(|A U0C0 |、|A V0C0 |、|A W0C0 |), [MIN] means MIN(|A U0C0 |、|A V0C0 |、|A W0C0 |).

[0531] Furthermore, MIN(a, b, c) represents the smallest value among values ​​a, b, and c. Additionally, the value β is specified as a pre-defined value (e.g., 50%).

[0532] In step S1003, if it is determined that equation (65) is true, then proceed from step S1003 to step S1004.

[0533] On the other hand, if it is determined that equation (65) is not valid (no), then proceed from step S1003 to step S1005.

[0534] Furthermore, as will be detailed later, Equation (65) is a formula for determining whether only one of the three current detectors 34 to 36 is abnormal. If Equation (65) is not true (no), it is determined that there is only one abnormality. If Equation (65) is true (yes), it is determined that there are two or three abnormalities.

[0535] Furthermore, the aforementioned values ​​α and β can be either constant or variable.

[0536] For example, in principle, when the current is zero, the degree of abnormality of the current detector cannot be observed, making anomaly diagnosis difficult. To avoid misjudgment even with such a small current value, the detected current value I can also be used as a reference. U I V I W The magnitude of the value makes the specified values ​​α and β variable.

[0537] Additionally, equation (65) in step S1003 determines whether the three elements (A) can be combined. U0C0 A V0C0 A W0C0 The formula classifies elements into two elements with high similarity and one element with low similarity to these two elements.

[0538] Equation (65) is an example of a determination method, and can also be used in place of Equation (65), for example, by using any cluster analysis method to make the same determination.

[0539] Step S1004

[0540] In step S1004, the inverter-side AC current detector anomaly judgment unit 721 judges multiple anomalies in current detectors 34, 35, and 36.

[0541] Alternatively, in step S1004, an instruction may be output to the display 73 to display information indicating that multiple current detectors are abnormal (e.g., a display such as "multiple current detectors are abnormal").

[0542] If the processing in step S1004 is completed, proceed to step S1012.

[0543] Furthermore, assuming the average anomaly of multiple current detectors 34, 35, and 36 is 0, i.e., the relative anomaly A... U0 A V0 A W0 The average of the calculated values ​​is 0 (i.e., (A) U0C +A V0C +A W0C When ) / 3=0), A is obtained according to equations (61)~(63). U0C0 =A U0C AV0C0 =A V0C A W0C0 =A W0C .

[0544] Therefore, the estimated abnormality value A of the current detector U1 A V1 A W1 Able to use the standardized outlier calculation value A U0C0 A V0C0 A W0C0 Represented as A U1 =A U0C0 A V1 =A V0C0 A W1 =A W0C0 .

[0545] Alternatively, the relative anomaly A can be presumed. U0 A V0 A W0 The average calculated value J(t) = (A U0C +A V0C +A W0C ) / 3, Estimated anomaly value A of the current detector U1 A V1 A W1 It can be expressed as follows.

[0546] A U1 (t)=(A U0C0 (t)+1)×J(t)-1

[0547] A V1 (t)=(A V0C0 (t)+1)×J(t)-1

[0548] A W1 (t)=(A W0C0 (t)+1)×J(t)-1

[0549] Regarding the calculation of J(t), for example, under the same operating conditions as in step S1005, a physical quantity B equivalent to the product of the average detection gain and current amplitude of multiple current detectors under normal operating conditions is pre-stored. I (t1), and B in step S1004 I (t) is compared, and thus calculated using the following formula.

[0550] J(t) = B I (t) / B I (t1)

[0551] Step S1005

[0552] In step S1005, the inverter-side AC current detector anomaly judgment unit 721 determines MAX(|A U0C0 |,|A V0C0 |,|A W0C0 |) Is it related to |A? U0C0 They are equal.

[0553] That is, determine whether the following equation (66) is true.

[0554] MAX(|A U0C0 |,|A V0C0 |,|A W0C0 |)=|A U0C0 |…(66)

[0555] If it is determined in step S1005 that equation (66) is true (yes), then proceed from step S1005 to step S1006.

[0556] On the other hand, if it is determined that equation (66) is not valid (no), then proceed from step S1005 to step S1007.

[0557] Step S1006

[0558] In step S1006, the inverter-side AC current detector anomaly judgment unit 721 judges that the U-phase current detector 34 is abnormal.

[0559] In addition, in step S1006, a command can also be output to the display 73 to display information indicating that the U-phase current detector 34 is abnormal (e.g., a display such as "U-phase current detector abnormal").

[0560] If the processing in step S1006 is completed, proceed to step S1012.

[0561] Furthermore, assuming the anomaly degree A of phase V current detector 35 and phase W current detector 36 is... V1 A W1 For A V1 =A W1 When = 0, the estimated value A of the anomaly degree of the U-phase current detector 34 U1 It can be calculated using the following formula (67).

[0562] A U1 =(3×A) U0C0 ) / (2-A U0C0 (67)

[0563] Equation (67) can be deduced, for example, as follows. Based on the above equations (26) and (29), we obtain equation (67a).

[0564] G U =G U0 ×(G U +G V +G W ) / 3…(67a)

[0565] If absolute anomaly A is used U A V A W and relative anomaly A U0 If we express it in terms of , then equation (67a) becomes equation (67b).

[0566] 1+A U =(1+A) U0 )×(A U +A V +A W +3) / 3…(67b)

[0567] Furthermore, assuming A V =A W When =0, we get the following equation (67c).

[0568] 1+A U =(1+A) U0 )×(A U +3) / 3

[0569] A U =(3×A) U0 ) / (2-A U0 (67c)

[0570] If we take the relative anomaly A on the right-hand side of the substitution equation (67c) U0 The standardized anomaly calculation value A is used. U0C0 The obtained value is used as the absolute anomaly A. U The estimated value is then used to obtain the above equation (67).

[0571] Step S1007

[0572] In step S1007, the inverter-side AC current detector anomaly judgment unit 721 determines |A U0C0 |、|A V0C0 |、|A W0C0 Is the largest value in |A|? V0C0 |, that is, to determine whether the following formula (68) is true.

[0573] MAX(|A U0C0 |,|A V0C0 |,|A W0C0 |)=|A V0C0 |…(68)

[0574] If it is determined in step S1007 that equation (68) is true (yes), then proceed from step S1007 to step S1008. On the other hand, if it is determined that equation (68) is false (no), then proceed from step S1007 to step S1009.

[0575] Step S1008

[0576] In step S1008, the inverter-side AC current detector anomaly judgment unit 721 judges that the V-phase current detector 35 is abnormal.

[0577] In step S1008, an instruction may also be output to the display 73 to display information indicating that the V-phase current detector 35 is abnormal (e.g., a display such as "V-phase current detector abnormal").

[0578] If the processing in step S1008 is completed, proceed to step S1012.

[0579] Furthermore, assuming the anomaly degree A of the U-phase current detector 34 and the W-phase current detector 36 is... U1 A W1 For A U1 =A W1 When = 0, the estimated value A of the anomaly degree of the V-phase current detector 35 V1 It can be calculated using the following formula (69). Formula (69) is obtained in the same way as formula (67) above.

[0580] A V1 =(3×A) V0C0 ) / (2-A V0C0 (69)

[0581] Step S1009

[0582] In step S1009, the inverter-side AC current detector anomaly judgment unit 721 determines that in |A U0C0 |、|A V0C0 |、|A W0C0 Is the largest value in |A|? W0C0 |, that is, determine whether the following formula (70) is true.

[0583] MAX(|A U0C0 |,|A V0C0 |,|A W0C0 |)=|A W0C0 |…(70)

[0584] If it is determined in step S1009 that equation (70) is true, then proceed from step S1009 to step S1010.

[0585] On the other hand, if it is determined that equation (70) is not valid (no), then proceed from step S1009 to step S1011.

[0586] However, if equations (66) and (68) are not true according to equations (66), (68), and (70), then equation (70) is true, so step S1009 is "yes".

[0587] Therefore, if S1007 is "No", step S1009 can be skipped and the process can proceed to step S1010.

[0588] Step S1010

[0589] In step S1010, the inverter-side AC current detector malfunction determination unit 721 determines that the W-phase current detector 36 is malfunctioning. Alternatively, in step S1010, a command may be output to the display 73 to display information indicating that the W-phase current detector 36 is malfunctioning (e.g., "W-phase current detector malfunction").

[0590] If the processing in step S1010 is completed, proceed to step S1012.

[0591] Furthermore, assuming the anomaly degree A of phase U current detector 34 and phase V current detector 35 is... U1 A V1 For A U1 =A V1 When = 0, the estimated value A of the anomaly degree of the W-phase current detector 36 W1 It is represented by the following equation (71). Furthermore, the calculation of equation (71) is obtained in the same way as the case of equation (67) above.

[0592] A W1 =(3×A) W0C0 ) / (2-A W0C0 )…(71)

[0593] Step S1011

[0594] In step S1011, the inverter-side AC current detector anomaly judgment unit 721 determines that all current detectors of U-phase current detector 34, V-phase current detector 35, and W-phase current detector 36 are normal.

[0595] Then, proceed to step S1012.

[0596] Step S1012

[0597] In step S1012, the subsequent steps S1004, S1006, S1008, S1010, and S1011 are accepted, and the next processing is performed.

[0598] In step S1012, the anomaly determination unit 727 estimates the anomaly degree of the current detector (e.g., A). U1 A V1 A W1 The abnormal judgment information of the current detector (abnormal judgment information of U-phase current detector, abnormal judgment information of V-phase current detector, abnormal judgment information of W-phase current detector) is output to the AC current estimation unit 722 on the inverter side.

[0599] Then, the series of exception handling and detection processes are completed (end).

[0600] Furthermore, in the flowchart above, the effect is illustrated using the structure of the inverter-side fault detector 72 as an example, but the effect is roughly the same for the converter-side fault detector 71.

[0601] <Other methods for the converter-side AC current detector anomaly detection unit 711 and inverter-side AC current detector anomaly detection unit 721 in step S105>

[0602] As described above, the converter-side AC current detector anomaly judgment unit 711 and the inverter-side AC current detector anomaly judgment unit 721 preferably utilize Kirchhoff's current law judgment method.

[0603] That is, according to Kirchhoff's Current Law, the sum of the true values ​​of the three-phase AC currents is 0. Therefore, if the sum of the detected values ​​of the AC current detector (the output of adder 7211) is 0, the AC current detector is normal. Alternatively, it is preferable to diagnose the AC current detector as abnormal if the output of adder 7211 is not 0.

[0604] For example, in Figure 6 In addition, the abnormality of current detectors 34, 35, and 36 can also be determined based on the output of current detectors 34, 35, and 36 and adder 7211.

[0605] First, if the output of adder 7211 exceeds a predetermined value, the phase of current detector 34, the phase of current detector 35, the phase of current detector 36, and the phase of the output of adder 7211 are calculated, for example, by Fourier transform.

[0606] Next, the phase difference between the adder 7211 and the current detector 34, the phase difference between the adder 7211 and the current detector 35, and the phase difference between the adder 7211 and the current detector 36 are calculated. In these phase difference calculations, the phase difference closest to 0 (radians) or π (radians) is selected.

[0607] Then, when the phase difference between the adder 7211 and the current detector 34 is closest to 0 (radians) or π (radians), the current detector 34 is diagnosed as abnormal.

[0608] Then, when the phase difference between the adder 7211 and the current detector 35 is closest to 0 (radians) or π (radians), the current detector 35 is diagnosed as abnormal.

[0609] Then, when the phase difference between the adder 7211 and the current detector 36 is closest to 0 (radians) or π (radians), it is possible to diagnose that the current detector 36 is abnormal.

[0610] <First example of inverter-side AC current estimation unit 722 in step S106>

[0611] Reference Figure 9 The first example of the inverter-side AC current estimation unit 722 in step S106 will be described.

[0612] Figure 9 This is a diagram illustrating a structural example of the inverter-side AC current estimation unit 722 in the inverter-side fault detector 72 of the power conversion apparatus according to the first embodiment of the present invention. Furthermore, Figure 9 Inverter-side fault detector 72 and Figure 3B The inverter-side fault detector 72 roughly corresponds to this.

[0613] exist Figure 9 In the inverter-side AC current estimation unit 722, the current detection value I is based on multiple current detectors 34, 35, and 36 corresponding to the U-phase, V-phase, and W-phase of the three-phase AC. U I V I W It is estimated that the current detection value should be the original current value that the current detector indicating an abnormality should detect when it is in normal condition.

[0614] As a method for estimating the original current detection value in the inverter-side AC current estimation unit 722, the relationship shown in the above equation (8) is used, that is, if each current detector is in a normal state, the combined current value after adding the current detection values ​​of the inverter-side current detectors 34, 35, and 36 is zero.

[0615] Based on the relationship that the synthesized current value is zero, in the case of any current detector malfunctioning, the correct current detection value of the malfunctioning current detector can be estimated by subtracting the sum of the current detection values ​​of the two current detectors on the healthy side from zero.

[0616] <Structural Example of Inverter Side AC Current Estimation Unit 722>

[0617] Next, an example of the specific structure and operation of the inverter-side AC current estimation unit 722 will be explained.

[0618] As mentioned above, Figure 9 This is a block diagram showing an example of the structure of a portion of the inverter-side AC current estimation unit 722, illustrating the relationship between the inverter-side AC current estimation unit 722, the inverter-side AC current detector anomaly judgment unit 721, and the inverter control device 6.

[0619] exist Figure 9 In the process, the current detection values ​​I of current detectors 34, 35, and 36 are input to the inverter-side AC current estimation unit 722 and the inverter-side AC current detector anomaly judgment unit 721. U I V I W .

[0620] Inverter-side AC current detector anomaly judgment unit 721 based on Figure 8 The flowchart determines whether any one of the current detectors 34, 35, and 36 has malfunctioned.

[0621] When the inverter-side AC current detector anomaly judgment unit 721 determines that any one of the current detectors 34, 35, and 36 is abnormal, it outputs the abnormality information of the current detector indicating the abnormality to the inverter-side AC current estimation unit 722.

[0622] For example, if the U-phase current detector 34 is determined to be abnormal, the abnormal judgment information of the U-phase current detector 34 is output.

[0623] When the inverter-side AC current estimation unit 722 receives abnormal judgment information from the U-phase current detector, it subtracts the current detection value I from the V-phase current detector 35 from zero. V The current detection value I of phase W current detector 36 W The sum is calculated and estimated to be the estimated value I detected when the U-phase current detector 34 is in normal operation. UH .

[0624] Then, the calculated estimated value IUH is input to the selection section 722a of the inverter-side AC current estimation section 722.

[0625] The current detection value I is input to the U-phase current detector 34 U and the estimated value -I V -I W When the selection unit 722a receives an abnormality judgment information from the U-phase current detector, it selects the estimated value -I. V -I W And output it.

[0626] In addition, when there is no abnormal judgment information from the U-phase current detector, the selection unit 722a selects and outputs the current detection value I. U .

[0627] Furthermore, when the inverter-side AC current estimation unit 722 receives abnormal judgment information from the U-phase current detector, it will input the current detection value I. VH =I V I WH =I W and the estimated value I UH =-I V -I W The output is sent to the inverter control unit 6.

[0628] On the other hand, without inputting abnormal judgment information from the U-phase current detector, the inverter-side AC current estimation unit 722 outputs the current detection value I to the inverter control device 6. UH =I U I VH =I V I WH =I W .

[0629] With this structure, even if the U-phase current detector 34 malfunctions, it can still replace the current detection value I. U And output the appropriate estimated value I UH .

[0630] As a result, it is possible to detect the current based on the output value I. V I W and the estimated value I UH For example, "temporary operation" is a process of temporarily continuing operation.

[0631] Furthermore, even if the V-phase current detector 35 or the W-phase current detector 36 malfunctions, the same processing action is performed, replacing the current detection value I. V And output the appropriate estimated value I VH Or replace the current detection value I W And output the appropriate estimated value I WH .

[0632] In addition, sometimes the operation continues based on the current detection value of the current detector that is not judged as abnormal and the current detection value estimated by the AC current estimation unit. In other cases, the operation continues based on multiple current detection values ​​estimated by the AC current estimation unit instead of the current detection value of the current detector.

[0633] <Structural Example of the Converter-Side AC Current Estimation Unit 712>

[0634] Regarding the AC current estimation section 712 on the converter side, the same structure as that of the AC current estimation section 722 on the inverter side can be adopted. It is only necessary to adopt the structure of replacing the U phase with the R phase, the V phase with the S phase, and the W phase with the T phase in the AC current estimation section 712 on the converter side.

[0635] The converter-side AC current estimation unit 712 is based on the current detection values ​​I from multiple current detectors 26, 27, and 28 corresponding to the R-phase, S-phase, and T-phase of the three-phase AC circuit. R I S I T This is the presumed current detection value that should be detected when the current detector indicating an abnormality is in normal operation.

[0636] The method for estimating the original current detection value is the same as that for the inverter-side AC current estimation unit 722.

[0637] <Second example of inverter-side AC current estimation unit 722 in step S106>

[0638] Reference Figure 10 A second example of the inverter-side AC current estimation unit 722 in step S106 will be described.

[0639] Figure 10 This is a diagram illustrating a second structural example of the inverter-side AC current estimation unit 722 in the inverter-side fault detector 72 of the power conversion device according to the first embodiment of the present invention.

[0640] In the second structural example of the inverter-side AC current estimation section 722, the structure of the inverter-side AC current estimation section 722 is replaced with... Figure 10 The structure shown.

[0641] Then, as the abnormality information output from the inverter-side AC current detector abnormality judgment unit 721 to the inverter-side AC current estimation unit 722, the estimated value of the abnormality of each current detector is input.

[0642] As an estimated value for anomaly, for example using Figure 8 The estimated value A recorded in step S1005 U1 A V1 AW1 .

[0643] The inverter-side AC current estimation unit 722 is based on the input current detection value I. U I V I W and the estimated value A of absolute anomaly U1 A V1 A W1 The estimated value I of the alternating current is calculated as follows (72) to (74). UH I VH I WH The current detection values ​​are assumed to be when current detectors 34, 35, and 36 are in normal operation.

[0644] I UH =I U ×(1+A U1 )…(72)

[0645] I VH =I V ×(1+A V1 )…(73)

[0646] I WH =I W ×(1+A W1 )…(74)

[0647] Then, the inverter-side AC current estimation unit 722 calculates the estimated value I of the AC current. UH I VH I WH The output is sent to the inverter control unit 6.

[0648] Furthermore, regarding the AC current estimation unit 712 on the converter side, it can be configured as described above, replacing the U phase with the R phase, the V phase with the S phase, and the W phase with the T phase.

[0649] That is, the converter-side AC current estimation unit 712 is based on the input current detection value I. R I S I T and the estimated value A of the anomaly. R1 A S1 A T1 Calculate the estimated value I of the alternating current. RH I SH I TH The estimated value I RH I SH I TH The output is sent to the converter control device 5.

[0650] <First example of inverter-side AC current anomaly detection unit 723 in steps S107 and S110>

[0651] exist Figure 4 In steps S107 and S110, the inverter-side AC current anomaly judgment unit 723 detects the estimated value I of the AC current. UH I VH I WH The phase difference.

[0652] Furthermore, in step S110, since the inverter-side AC current estimation section 722 was not performed ( Figure 9 The switching of signals in ) so I UH =I U I VH =I V I WH =I W .

[0653] Furthermore, the estimated value I of the alternating current is defined using amplitude and phase difference as shown in equations (75) to (77). UH I VH I WH .

[0654] I UH =I U0 ×cos(ωt)…(75)

[0655] I VH =I V0 ×cos(ωt-θ UV )…(76)

[0656] I WH =I W0 ×cos(ωt-θ UV -θ VW )…(77)

[0657] In the above equations (75) to (77), I U0 I V0 I W0 These are the estimated values ​​I of the alternating current. UH I VH I WH The current amplitude, θ UV isI UH with I VH The phase difference, θ VW isI VH with I WH The phase difference.

[0658] When I is set WH with I UHThe phase difference is θ WU At θ UV ≈θ VW ≈θ WU When the value is approximately 2π / 3, equation (78) holds true.

[0659] θ WU =2π-θ UV -θ VW …(78)

[0660] The following is used to determine the phase difference θ. UV θ VW θ WU An example of a simple method.

[0661] Figure 11 This is a diagram illustrating an example of the structure of the inverter-side AC current anomaly detection unit 723.

[0662] Figure 11 This illustrates an example of a simple method for determining phase difference.

[0663] exist Figure 11 In the inverter-side AC current anomaly detection unit 723, there are multipliers 7231 (7231U, 7231V, 7231W), multipliers 7232 (7232CU, 7232CV, 7232CW), filters 7233 (7233U, 7233V, 7233W), filters 7234 (7234CU, 7234CV, 7234CW), and a phase difference calculation unit 7235.

[0664] The estimated value I of the alternating current is defined as in equations (75) to (77) above. UH I VH I WH In the case of multipliers 7231U, 7231V, and 7231W, the outputs are represented by the following equations (79) to (81).

[0665] I UH 2 =1 / 2×I U0 2 (1+cos(2ωt))…(79)

[0666] I VH 2 =1 / 2×I V0 2 (1+cos(2ωt-2θ UV ))…(80)

[0667] I WH 2 =1 / 2×I W02 (1+cos(2ωt-2θ UV -2θ VW ))…(81)

[0668] If we consider I as represented by equations (79) to (81) UH 2 I VH 2 I WH 2 High-frequency components are removed through filtering; that is, if the periodic variations of the trigonometric function are removed, the output F of filters 7233U, 7233V, and 7233W will be... UU F VV F WW As shown in equations (82) to (84).

[0669] F UU =1 / 2×I U0 2 …(82)

[0670] F VV =1 / 2×I V0 2 …(83)

[0671] F WW =1 / 2×I W0 2 …(84)

[0672] In addition, the estimated value I of the alternating current UH I VH I WH When defined as in equations (75) to (77) above, the outputs of multipliers 7232CU, 7232CV, and 7232CW are represented by equations (85) to (87).

[0673] I UH I VH =1 / 2×I U0 I V0 (cos(2ωt-θ UV )+cos(θ UV ))…(85)

[0674] I VH I WH =1 / 2×I V0 I W0 (cos(2ωt-2θ UV -θ VW )+cos(θ UV ))…(86)

[0675] IWH I UH =1 / 2×I W0 I U0 (cos(2ωt-θ UV -θ VW )+cos(θ UV +θ VW ))…(87)

[0676] When I is represented by equations (85) to (87) UH I VH I VH I WH I WH I UH When performing filtering to remove high-frequency components, that is, removing the periodic variations of trigonometric functions, the output F of filters 7234CU, 7234CV, and 7234CW... UV F VW F WU As shown in equations (88) to (90).

[0677] F UV =1 / 2×I U0 I V0 ×cos(θ UV )…(88)

[0678] F VW =1 / 2×I V0 I W0 ×cos(θ VW )…(89)

[0679] F WU =1 / 2×I W0 I U0 ×cos(θ WU )…(90)

[0680] Therefore, according to equations (82)~(84) and (88)~(90), cos(θ) UV ), cos(θ) VW ), cos(θ) WU ) are the outputs of filters 7233 and 7234, as shown in equations (91) to (93).

[0681] cos(θ UV ) = F UV / √(F UU ×F VV )…(91)

[0682] cos(θ VW ) = F VW / √(F VV ×FWW )…(92)

[0683] cos(θ WU ) = F WU / √(F WW ×F UU )…(93)

[0684] In addition, the phase difference is represented by the following equations (94) to (96).

[0685] θ UV =acos(F UV / √(F UU ×F VV ))…(94)

[0686] θ VW =acos(F VW / √(F VV ×F WW ))…(95)

[0687] θ WU =acos(F WU / √(F WW ×F UU ))…(96)

[0688] As described above (for example, equations (75) to (77)), the estimated value I of the alternating current is used. UH I VH I WH Assuming a sinusoidal current, the phase difference θ calculated from equations (94) to (96) is... UV θ VW θ WU This represents the phase difference between phases U, V, and W under ideal conditions with no current pulsation.

[0689] In the estimated value I of alternating current UH I VH I WH In the case of pulsating components, θ is obtained from equations (94) to (96). UV θ VW θ WU And the calculated θ UV θ VW θ WU For θ UV +θ VW +θ WU ≠2π.

[0690] Therefore, the standardized phase difference θ that makes equations (97) to (100) valid is newly introduced. UV1 θ VW1 θWU1 .

[0691] θ DIF =(θ UV +θ VW +θ WU -2π) / 3…(97)

[0692] θ UV1 =θ UV -θ DIF …(98)

[0693] θ VW1 =θ VW -θ DIF …(99)

[0694] θ WU1 =θ WU -θ DIF …(100)

[0695] In satisfying I UH +I VH +I WH When θ = 0, if θ UV1 θ VW1 θ WU1 θ VW1 If I is the smallest, then UH The amplitude is largest when θ is θ. WU1 If I is the smallest, then VH The amplitude is largest when θ is θ. UV1 If I is the smallest, then WH The amplitude is the largest.

[0696] Therefore, by comparing the phase difference θ UV1 θ VW1 θ WU1 It can detect the phase that may be partially short-circuited, that is, the phase with the largest current amplitude.

[0697] <Abnormal detection and processing in inverter-side AC current abnormality detection unit 723>

[0698] Figure 12 It means Figure 11 The flowchart shows an example of the anomaly detection processing in the inverter-side AC current anomaly detection unit 723. Hereinafter, according to... Figure 12 The flowchart illustrates the steps for exception detection and handling.

[0699] Step S2001

[0700] If the abnormal judgment process in the inverter-side AC current abnormal judgment unit 723 starts, then proceed to step S2001.

[0701] In step S2001, the inverter-side AC current anomaly detection unit 723 calculates the standardized phase difference θ using the aforementioned equations (98) to (100). UV1 θ VW1 θ WU1 .

[0702] Step S2002

[0703] Step S2002 is the step of determining whether all currents are normal. The inverter-side AC current anomaly judgment unit 723 determines the normality of the calculated standardized phase difference θ. UV1 θ VW1 θ WU1 Determine θ UV1 θ VW1 θ WU1 Whether the minimum value within is less than a predetermined value γ1 (e.g., 0.98 × 2π / 3).

[0704] That is, whether the judgment formula (101) is true. In addition, MIN(a, b, c) represents the smallest value among the values ​​a, b, and c.

[0705] MIN(θ UV1 θ VW1 θ WU1 ) < Specified value γ1…(101)

[0706] In step S2002, when it is determined that equation (101) is true, the process proceeds from step S2002 to step S2003.

[0707] On the other hand, in step S2002, if it is determined that equation (101) is not valid (no), that is, in the standardized phase difference θ UV1 θ VW1 θ WU1 If all values ​​are above the specified value γ1, proceed from step S2002 to step S2009.

[0708] Furthermore, the processing of step S2009 will be described later.

[0709] Step S2003

[0710] In step S2003, the inverter-side AC current anomaly detection unit 723 determines that the normalized phase difference θ UV1 θ VW1 θ WU1 MIN(θ) UV1 θ VW1 θ WU1 Is it related to θ? VW1 equal.

[0711] That is, determine whether the following equation (102) is true.

[0712] MIN(θ UV1 θ VW1 θ WU1 )=θ VW1 …(102)

[0713] When it is determined in step S2003 that equation (102) is true, proceed from step S2003 to step S2004.

[0714] On the other hand, if it is determined that equation (102) is not valid (no), then proceed from step S2003 to step S2005.

[0715] Step S2004

[0716] In step S2004, the inverter-side AC current anomaly judgment unit 723 judges that the U-phase current is the maximum.

[0717] In step S2004, an instruction may also be output to the display 73 to make the display 73 display information indicating that the U-phase current is the maximum (e.g., a display such as "U-phase current is the maximum").

[0718] Furthermore, in step S2004, since the U-phase current is the largest, it can also be determined that a partial short circuit of the U-phase circuit is possible.

[0719] If the processing in step S2004 is completed, proceed to step S2010.

[0720] Step S2005

[0721] In step S2005, the inverter-side AC current anomaly detection unit 723 determines MIN(θ) UV1 θ VW1 θ WU1 Is it related to θ? WU1 Equal. That is, determine whether the following equation (103) is true.

[0722] MIN(θ UV1 θ VW1 θ WU1 )=θ WU1 …(103)

[0723] When it is determined in step S2005 that equation (103) is true, proceed from step S2005 to step S2006.

[0724] On the other hand, if it is determined that equation (103) is not valid (no), then proceed from step S2005 to step S2007.

[0725] Step S2006

[0726] In step S2006, the inverter-side AC current anomaly judgment unit 723 judges that the V-phase current is the maximum.

[0727] In step S2006, an instruction may also be output to the display 73 to make the display 73 display information indicating that the V-phase current is the maximum (e.g., a display such as "V-phase current is the maximum").

[0728] Furthermore, in step S2006, since the V-phase current is the largest, it can also be determined that a partial short circuit of the V-phase circuit is possible.

[0729] If the processing in step S2006 is completed, proceed to step S2010.

[0730] Step S2007

[0731] In step S2007, the inverter-side AC current anomaly detection unit 723 determines MIN(θ) UV1 θ VW1 θ WU1 Is it related to θ? UV1 Equal. That is, determine whether the following equation (104) is true.

[0732] MIN(θ UV1 θ VW1 θ WU1 )=θ UV1 …(104)

[0733] In step S2007, if it is determined that equation (104) is true, then proceed from step S2007 to step S2008.

[0734] On the other hand, if it is determined that equation (104) is not valid (no), then proceed from step S2007 to step S2009.

[0735] However, according to equations (102), (103), and (104), if equations (102) and (103) are not true, then equation (104) is true, so step S2007 becomes (yes). Therefore, if S2005 is (no), step S2007 can be skipped and the process can proceed to step S2008.

[0736] Step S2008

[0737] In step S2008, the inverter-side AC current anomaly judgment unit 723 judges that the W-phase current is the maximum.

[0738] In step S2008, an instruction may also be output to the display 73 to display information indicating that the W-phase current is the largest (e.g., a display such as "W-phase current is the largest").

[0739] Furthermore, in step S2008, since the W-phase current is the largest, it can also be determined that a partial short circuit of the W-phase circuit is possible.

[0740] If the processing in step S2008 is completed, proceed to step S2010.

[0741] Step S2009

[0742] In step S2009, the inverter-side AC current anomaly judgment unit 723 judges that the three-phase current is balanced and normal.

[0743] Step S2010

[0744] In step S2010, the subsequent steps S2004, S2006, S2008, and S2010 are accepted, and the next processing is performed.

[0745] In step S2010, the inverter-side AC current anomaly detection unit 723 normalizes the phase difference θ UV1 θ VW1 θ WU1 The abnormal current judgment information (maximum U-phase current, maximum V-phase current, maximum W-phase current, and three-phase current balance) is output to the display 73.

[0746] Then, the series of exception handling checks and processes are completed.

[0747] Furthermore, the above explanation of the effect is based on the structure of the inverter-side AC current anomaly detection unit 723, but the same effect is also produced for the converter-side AC current anomaly detection unit 713.

[0748] Furthermore, the inverter-side AC current anomaly detection unit 723 and the converter-side AC current anomaly detection unit 713 share a common structure and are designated as AC current anomaly detection units (713, 723), having the following features: Figure 12 The outline of the structure of the power conversion device of the AC current abnormality judgment unit that operates according to the flowchart shown can be described as follows.

[0749] That is, "the AC current anomaly judgment unit in the power conversion device is characterized by calculating the standardized phase difference of the AC current of multiple phases. When the minimum value of the multiple standardized phase differences is greater than a predetermined value, it is judged that the current of each phase is normal. When the minimum value of the multiple standardized phase differences is less than the predetermined value, the minimum value of the multiple standardized phase differences and the standardized phase difference of each phase are compared in turn. When the minimum value of the multiple standardized phase differences is equal to the standardized phase difference of the specified phase, it is judged that the current amplitude of that phase is the largest and that the risk of local short circuit in that phase is high."

[0750]

[0751] exist Figure 4 In steps S107 and S110, the inverter-side AC current anomaly judgment unit 723 may not detect the estimated value I of the AC current. UH I VH I WH The phase difference is used to detect the amplitude.

[0752] That is, the amplitude I of the aforementioned equations (75) to (77) can also be detected. U0 I V0 I W0 .

[0753] Figure 13 This indicates that it is used to calculate the amplitude (I) U0 I V0 I W0 An example of a simple method.

[0754] Figure 13 This is another example of the structure of the inverter-side AC current anomaly detection unit 723.

[0755] exist Figure 13 In the inverter side, the AC current abnormality judgment unit 723 is composed of multipliers 7231 (7231U, 7231V, 7231W), filters 7233 (7233U, 7233V, 7233W) and amplitude calculation unit 7236.

[0756] That is, delete Figure 11 It is composed of multipliers 7232 (7232CU, 7232CV, 7232CW) and filters 7234 (7234CU, 7234CV, 7234CW).

[0757] The estimated value I of the alternating current is defined as in equations (75) to (77) above. UH I VH IWH In the case of the above equations (82) to (84), the amplitude I U0 I V0 I W0 Estimated value I U1 I V1 I W1 It is represented by equations (105) to (107).

[0758] I U1 =√(2F) UU )…(105)

[0759] I V1 =√(2F) VV )…(106)

[0760] I W1 =√(2F) WW )…(107)

[0761] If the estimated value of the amplitude (estimated amplitude) I U1 I V1 I W1 I in U1 If I is the largest, then UH The amplitude is the largest if I V1 If I is the largest, then VH The amplitude is the largest if I W1 If I is the largest, then WH The amplitude is the largest.

[0762] Therefore, by comparing the estimated value I of the amplitude U1 I V1 I W1 The phase with the largest current amplitude can detect the possibility of a partial short circuit.

[0763] <Abnormal detection and processing in inverter-side AC current abnormality detection unit 723>

[0764] Figure 14 It means Figure 13 The flowchart shows an example of the anomaly detection processing in the anomaly detection unit 723 of the inverter-side AC current detector. Hereinafter, according to... Figure 14 The flowchart illustrates the steps for exception detection and handling.

[0765] Step S3001

[0766] If the abnormal judgment process in the inverter-side AC current abnormal judgment unit 723 starts, then proceed to step S3001.

[0767] In step S3001, the inverter-side AC current anomaly judgment unit 723 calculates the amplitude estimation value I using the above formulas (105) to (107). U1 I V1 I W1 .

[0768] Step S3002

[0769] Step S3002 is the step of determining whether all currents are normal. The inverter-side AC current anomaly judgment unit 723 determines the calculated amplitude estimate value I. U1 I V1 I W1 Determine I U1 I V1 I W1 Is the maximum value in [the range] greater than a predetermined value γ2 (e.g., 1.05 × (I[value]))? U1 +I V1 +I W1 ) / 3).

[0770] That is, determine whether the following equation (108) holds true. In addition, MAX(a, b, c) represents the largest value among values ​​a, b, and c.

[0771] MAX(I U1 I V1 I W1 )>Specified value γ2…(108)

[0772] When it is determined in step S3002 that equation (108) is true, proceed from step S3002 to step S3003.

[0773] On the other hand, when it is determined in step S3002 that equation (108) is not valid (no), that is, at the amplitude estimation value I U1 I V1 I W1 If all values ​​are below the specified value γ2, proceed from step S3002 to step S3009.

[0774] Furthermore, the processing in step S3009 will be described later.

[0775] Step S3003

[0776] In step S3003, the inverter-side AC current anomaly judgment unit 723 determines the MAX(I) of the following formula (109). U1 I V1 I W1 Is it related to I? U1 They are equal. That is, whether the judgment (102) is true.

[0777] MAX(I U1 I V1 I W1 ) = I U1 …(109)

[0778] When it is determined in step S3003 that equation (109) is true, proceed from step S3003 to step S3004.

[0779] On the other hand, if it is determined that equation (109) is not true (no), then proceed from step S3003 to step S3005.

[0780] Step S3004

[0781] In step S3004, the inverter-side AC current anomaly judgment unit 723 judges that the U-phase current is the maximum.

[0782] In step S3004, an instruction may also be output to the display 73 to make the display 73 display information indicating that the U-phase current is the maximum (e.g., a display such as "U-phase current is the maximum").

[0783] Furthermore, in step S3004, since the U-phase current is the largest, it can also be determined that a partial short circuit of the U-phase circuit is possible.

[0784] If the processing in step S3004 is completed, proceed to step S3010.

[0785] Step S3005

[0786] In step S3005, the inverter-side AC current anomaly detection unit 723 determines the MAX(I) of the following formula (110). U1 I V1 I W1 Is it related to I? V1 They are equal. That is, whether the judgment (103) is true.

[0787] MAX(I U1 I V1 I W1 ) = I V1 …(110)

[0788] When it is determined in step S3005 that equation (110) is true, proceed from step S3005 to step S3006.

[0789] On the other hand, if it is determined that equation (110) is not true (no), then proceed from step S3005 to step S3007.

[0790] Step S3006

[0791] In step S3006, the inverter-side AC current anomaly judgment unit 723 judges that the V-phase current is the maximum.

[0792] In step S3006, an instruction may also be output to the display 73 to make the display 73 display information indicating that the V-phase current is the maximum (e.g., a display such as "V-phase current is the maximum").

[0793] Furthermore, in step S3006, since the V-phase current is the largest, it can also be determined that a partial short circuit of the V-phase circuit is possible.

[0794] If the processing in step S3006 is completed, proceed to step S3010.

[0795] Step S3007

[0796] In step S3007, the inverter-side AC current anomaly judgment unit 723 determines the MAX(I) of the following formula (111). U1 I V1 I W1 Is it related to I? W1 They are equal. That is, whether the judgment (111) is true.

[0797] MAX(I U1 I V1 I W1 ) = I W1 …(111)

[0798] When it is determined in step S3007 that equation (104) is true, proceed from step S3007 to step S3008.

[0799] On the other hand, if it is determined that equation (111) is not true (NO), then proceed from step S3007 to step S3009. However, according to equations (109), (110), and (111), if equations (109) and (110) are not true, then equation (111) is true, so step S3007 becomes (Yes). Therefore, if S3005 is (NO), the process of step S3007 can be skipped and the process can proceed to step S3008.

[0800] Step S3008

[0801] In step S3008, the inverter-side AC current anomaly judgment unit 723 judges that the W-phase current is the maximum.

[0802] In step S3008, an instruction may also be output to the display 73 to make the display 73 display information indicating that the W phase current is the largest (e.g., a display such as "W phase current is the largest").

[0803] Furthermore, in step S3008, since the W-phase current is the largest, it can also be determined that a partial short circuit of the W-phase circuit is possible.

[0804] If the processing in step S3008 is completed, proceed to step S3010.

[0805] Step S3009

[0806] In step S3009, the inverter-side AC current anomaly judgment unit 723 judges that the three-phase current is balanced and normal.

[0807] Step S3010

[0808] In step S3010, the subsequent steps S3004, S3006, S3008, and S3010 are accepted, and the next processing is performed.

[0809] In step S3010, the inverter-side AC current anomaly judgment unit 723 estimates the amplitude value I. U1 I V1 I W1 The abnormal current judgment information (maximum U-phase current, maximum V-phase current, maximum W-phase current, and three-phase current balance) is output to the display 73.

[0810] Then, the series of exception handling and detection processes are completed (end).

[0811] Furthermore, in the above description, the effect was explained using the structure of the inverter-side AC current anomaly detection unit 723 as an example, but the same effect is also produced for the converter-side AC current anomaly detection unit 713.

[0812] Furthermore, the above steps S3001 to S3010 are shown in the flowchart below: as " Figure 4 "A second example of the inverter-side AC current anomaly judgment unit 723 in steps S107 and S110", Figure 4 In steps S107 and S110, the AC current anomaly judgment unit 723 detects the amplitude and executes the judgment, instead of using the estimated value I of the AC current. UH I VH I WH The phase difference.

[0813] Furthermore, the inverter-side AC current anomaly detection unit 723 and the converter-side AC current anomaly detection unit 713 share a common structure and are designated as AC current anomaly detection units (713, 723), having the following features: Figure 14 The outline of the structure of the power conversion device of the AC current abnormality judgment unit that operates according to the flowchart shown can be described as follows.

[0814] That is, "the AC current anomaly judgment unit in the power conversion device detects the amplitude of the AC current of multiple phases, calculates the amplitude estimate of each phase based on the amplitude, and judges that the current of each phase is normal when the maximum value of the multiple amplitude estimate values ​​is less than or equal to a predetermined value. When the maximum value of the multiple amplitude estimate values ​​is greater than the predetermined value, the maximum value of the multiple amplitude estimate values ​​is compared with the amplitude estimate of each phase in turn. When the maximum value of the multiple amplitude estimate values ​​is equal to the amplitude estimate of a predetermined phase, it is judged that the current amplitude of that phase is the largest, and it is judged that a partial short circuit of that phase may occur."

[0815] <Other implementation methods related to the inverter-side AC current anomaly detection unit 723 in steps S107 and S110>

[0816] It can also be used as a substitute for Figure 11 Calculate the standardized phase difference θ UV1 θ VW1 θ WU1 Regarding frequency ω for I UH I VH I WH Perform a Fourier transform and calculate the estimated phase difference θ based on the current phase components of each phase after the Fourier transform. UV θ VW θ WU .

[0817] Alternatively, it can be used as a substitute in Figure 13 The calculated amplitude estimate I U1 I V1 I W1 The estimated value I for calculating alternating current. UH I VH I WH The effective value of the current is used for anomaly detection.

[0818] Alternatively, it can be used as a substitute in Figure 13 The calculated amplitude estimate I U1 I V1 I W1 The estimated value I for alternating current. UH I VH I WH Fourier transform is performed to calculate the amplitude of each phase related to frequency ω, and the amplitude of each phase is used to determine anomalies.

[0819] <Effects of the First Implementation Method>

[0820] According to the present invention, a power conversion device is provided that can distinguish between abnormalities in the current detector and AC current abnormalities caused by factors other than the current detector.

[0821] Furthermore, even if a partial short circuit occurs in a motor that is a three-phase load, it will not be misdiagnosed as an abnormality of the current detector.

[0822] Furthermore, even when both an AC current detector malfunction and three-phase imbalance occur simultaneously, the malfunction can be detected with minimal error.

[0823] Second Embodiment: Power Conversion Device

[0824] Reference Figure 15 The power conversion device according to the second embodiment of the present invention will be described.

[0825] Figure 15 This is a diagram illustrating an example of the structure of the power conversion device 102 according to the second embodiment of the present invention.

[0826] In addition, Figure 15 In the middle, to and Figure 1 The same structure as the power conversion device 100 of the first embodiment shown is labeled with the same reference numerals. In the power conversion device 101, Figure 1 The 3-level converter unit 2 and inverter unit 3 in the power conversion device 100 shown are replaced with Figure 15 The converter unit 2B and inverter unit 3B with 2-level voltages are shown.

[0827] 2-level converter unit 2B

[0828] exist Figure 15 In the power conversion device 101, the converter unit 2B and inverter unit 3B are configured as 2-level converters, thus simplifying the circuits of each converter unit 2B and inverter unit 3B.

[0829] For example, the number of transistors was reduced, and no further action was required. Figure 1 The C wiring (41) has a neutral (zero) potential, while the P wiring 40 has only a positive potential and the N wiring 42 has a negative potential. Since there is no... Figure 1 The C wiring 41 in the circuit is used to detect the DC voltage. Therefore, the DC voltage detector is composed of a DC voltage detector 29 that detects the potential between the electrodes of the smoothing capacitors 22 and 23 on the converter side.

[0830] exist Figure 15 In the converter unit 2B, the converter power conversion sections 21BR, 21BS, and 21BT are composed of two transistors and two diodes made of IGBTs.

[0831] Two transistors are connected in series. The collector of the first transistor is connected to the P-line 40, and the emitter of the second transistor is connected to the N-line 42.

[0832] Two transistors are connected to diodes in reverse parallel.

[0833] In addition, Figure 15 In the text, the converter power conversion unit 21B is described using three converter power conversion units (21BR, 21BS, 21BT) as representatives. However, the converter power conversion unit 21B in the power conversion device 100 of the first embodiment ( Figure 1 ), Inverter power conversion section 31 ( Figure 1 In fact, as Figure 2A , Figure 2B As shown, the R, S, and T phases of a 3-phase AC circuit are each composed of three converter power conversion units (21R, 21S, 21T), or the U, V, and W phases of a 3-phase AC circuit are each composed of three inverter power conversion units (31U, 31V, 31W). Figure 15 The converter power conversion unit 21B and inverter power conversion unit 31B are simplified to represent three units.

[0834] In addition, the DC power lines, namely P-line 40 and N-line 42, of the three converter power conversion sections (21BR, 21BS, 21BT) are shared within the converter power conversion sections (21BR, 21BS, 21BT). That is, the three-phase AC power (voltage) of phase R, phase S, and phase T is converted into a common DC power (voltage).

[0835] In addition, the three converter power conversion units (21BR, 21BS, 21BT) are uniformly controlled through converter control device 5.

[0836] The converter unit 2B is equipped with an R-phase current detector 26, an S-phase current detector 27, and a T-phase current detector 28, which respectively detect the current flowing through the R-phase, S-phase, and T-phase of the three-phase AC.

[0837] in addition, Figure 15 The smoothing capacitors 22 and 23 in the converter unit 2B shown are directly inherited. Figure 1 The smoothing capacitors 22 and 23 in the converter unit 2 shown are illustrated. However, since there is no C-line 41 (neutral point potential), the smoothing capacitors 22 and 23 can also be combined into one capacitor.

[0838] In addition, such as Figure 15As shown, when smoothing capacitors 22 and 23 are connected in series, the electrostatic capacitance of the integrated capacitor decreases, but the withstand voltage across the integrated capacitor increases.

[0839] 3B 2-level inverter unit

[0840] exist Figure 15 In the middle, inverter unit 3B will Figure 1 The 3-level inverter unit 3 is replaced with a 2-level inverter unit. The structure of the 2-level inverter unit 3B is the same as... Figure 15 The common changes to the 2-level converter unit 2B are as follows. In addition, since it is a structural design, repeated descriptions are omitted.

[0841] Power Conversion Device 101

[0842] exist Figure 15 In the power conversion device 101 shown, the structures other than the converter unit 2B and the inverter unit 3B are similar to those in the power conversion device 101. Figure 1 The power conversion device 100 shown in the first embodiment is substantially the same, so repeated descriptions are appropriately omitted.

[0843] As described above, the power conversion device 101 includes a 2-level converter unit 2B and an inverter unit 3B.

[0844] The current pulsation differs depending on the conversion method (pulse waveform) between 3-level and 2-level, but in the power conversion device 101, the converter-side fault detector 71 also performs the same processing as in the first embodiment based on the current detection values ​​of the current detectors 26, 27, and 28.

[0845] Furthermore, it can properly determine whether there are any abnormalities in current detectors 26, 27, 28 and AC currents (e.g., AC power supply 1) caused by factors other than current detectors 26, 27, 28.

[0846] In addition, the inverter-side fault detector 72 performs the same processing as in the first embodiment based on the current detection values ​​of the current detectors 34, 35, and 36, thereby enabling it to appropriately determine whether there are any abnormalities in the current detectors 34, 35, and 36, as well as in the AC current (e.g., motor 4) caused by factors other than the current detectors 34, 35, and 36.

[0847] Furthermore, as described above, in the second embodiment, even when the power conversion device 101 is equipped with a 2-level converter unit 2B and an inverter unit 3B, it is possible to appropriately determine the current detectors 34, 35, 36 and any abnormalities in the AC current caused by factors other than the current detectors 34, 35, 36.

[0848] Furthermore, by setting the converter unit 2B and inverter unit 3B to 2-level, the circuit structure of the converter unit 2B and inverter unit 3B can be simplified.

[0849] <Effects of the Second Implementation>

[0850] The power conversion device 101 of the second embodiment is configured to have a converter unit 2B and an inverter unit 3B with two levels, thereby simplifying the circuit structure and achieving the effects of low cost and miniaturization.

[0851] <Supplement to the First and Second Embodiments>

[0852] In the first to second embodiments described above, the abnormal detection of the current detector in the power conversion device between the AC power supply 1 and the motor 4, which serves as the load, was explained. However, the structure is not limited to this; for example, an AC converter (e.g., a transformer) that converts AC voltage to AC voltage may be provided between the AC power supply 1 and the converter unit 2.

[0853] Alternatively, an AC converter (e.g., a transformer) that converts AC voltage to AC can be installed between the inverter unit 3 and the motor 4.

[0854] The present invention can also be applied to current detectors of all phases (e.g., 3 phases) in the above structure, configured between the power converter (converter unit 2) and the power source, or between the power converter (inverter unit 3) and the load (motor 4), as well as to the judgment of abnormal AC current caused by factors other than the current detectors.

[0855] <Abstract Judgment of Structures Lacking DC / AC Power Conversion Devices>

[0856] Furthermore, in the first to second embodiments described above, the abnormality detection of current detectors 26 to 28 and 34 to 36, which detect the current of each phase of the three-phase AC wiring of the power conversion device, is explained.

[0857] However, the method for determining anomalies described in the first to second embodiments is not limited to the current detector provided by the power conversion device that converts DC to AC.

[0858] Reference Figure 16 An example of anomaly detection in a structure that does not possess the DC / AC power conversion device is explained.

[0859] Figure 16 This diagram illustrates an example of a structure that supplies three-phase AC power from AC power source 1 to motor 4, which is a three-phase load, via AC-AC power converter 9.

[0860] exist Figure 16 In the process, a U-phase current detector 34, a V-phase current detector 35, and a W-phase current detector 36 are installed on the three-phase AC wiring line input to the motor 4.

[0861] The AC-AC power converter 9 is controlled by the AC-AC power converter control device 8.

[0862] The current detection value I detected by current detectors 34, 35, and 36 U I V I W It is input into the exception checker 72.

[0863] The anomaly detector 72 is a device for determining anomalies in the current detectors 34, 35, and 36, and has the same structure and function as the inverter-side anomaly detector 72 described in the first embodiment above.

[0864] In addition, motor 4 can also be connected in a star or delta configuration.

[0865] In addition, Figure 16 In the example, a 3-phase motor 4 is shown as a load, but the load is not limited to motors.

[0866] In addition, Figure 1 , Figure 15 , Figure 16 The example illustrates a three-phase alternation scenario, but it is not necessarily limited to three phases; it can also be a multi-phase scenario beyond three phases.

[0867] Third Implementation Method

[0868] Based on the above-described first embodiment, the abnormality calculation unit (7117) of the power conversion device is used. Figure 5 ), 7217 Figure 6 In the third embodiment, a structure and method for determining abnormalities by associating the operating conditions of the AC power supply or load device (motor) with those of the AC current detector are further described.

[0869] Figure 17 This is a diagram illustrating a structural example of the AC current detector abnormality judgment unit 731 of the power conversion device according to the third embodiment of the present invention.

[0870] exist Figure 17 In the middle, for in Figure 5 , Figure 6The structure of the AC current detector anomaly judgment unit (converter-side AC current detector anomaly judgment unit 711, inverter-side AC current detector anomaly judgment unit 721) above the anomaly calculation unit (7117, 7217) described in the text further considers the operating status of AC power supply 1 or motor (load device) 4 to judge the anomaly of the current detector.

[0871] exist Figure 17 In the middle, the AC current detector abnormality judgment unit 731 includes a converter-side AC current detector abnormality judgment unit 711 ( Figure 17 , Figure 3A , Figure 5 ), Inverter-side AC current detector anomaly judgment unit 721 ( Figure 17 , Figure 3B , Figure 6 The system includes a second arithmetic unit 7311, an operation condition determination unit 7313 (including a storage unit 7312), and an exception determination unit 7315 (including a third arithmetic unit 7314). Furthermore, as described above, the operation condition determination unit 7313 internally includes a storage unit 7312. Additionally, the exception determination unit 7315 internally includes a third arithmetic unit 7314.

[0872] The AC current detector anomaly judgment unit 731 inputs the current detection values ​​I of the R-phase, S-phase, and T-phase detected by the current detectors on the converter unit 2 side. R I S I T Additionally, the input is the current detection values ​​I of phase U, phase V, and phase W detected by the current detector on side 3 of the inverter unit. U I V I W .

[0873] Additionally, the operating conditions S1 of the AC power supply 1 and the operating conditions S2 of the load device (motor) 4 are input to the AC current detector fault determination unit 731. Furthermore, in Figure 17 For ease of description, the operating conditions S1 and S2 are described together using a single signal line.

[0874] In the above description of the structure, operation and function of the AC current detector abnormality judgment unit 731, some of the AC current detector abnormality judgment unit 711 on the converter side and the AC current detector abnormality judgment unit 721 on the inverter side are repeated, but the structure will be reorganized and described again below.

[0875] Converter-side AC current detector anomaly detection unit 711

[0876] The converter-side AC current detector anomaly detection unit 711 was described in the power conversion device 100 of the first embodiment. However, since the description involves multiple aspects, some parts are repeated. But from the point of view of structure and function, it will be shown in a more organized manner below. The converter-side AC current detector anomaly detection unit 711 is composed of <1A> to <10A> as follows.

[0877] <1A> Calculate the current detection values ​​(I) of multiple phases detected by multiple current detectors (26, 27, 28). R I S I T The first sum of I) C0 The first addition part 7111.

[0878] <2A> Calculate the first sum I for each of the multiple phases. C0 With current detection value (I) R I S I T The product of (D) is the first product (D) R D S D T The first multiplication part of ) (7112R, 7112S, 7112T).

[0879] <3A> Reduce or remove multiple first products (D) respectively. R D S D T The first filter (7113R, 7113S, 7113T) contains the AC component.

[0880] <4A> Calculate the product of two different current detection values, i.e., the second product (I). R I S I S I T I T I R The second multiplication part of ) (7114CT, 7114CR, 7114CS).

[0881] <5A> Calculate the second product (I) with respect to multiple second products. R I S I S I T I T I R The second addition part of the second summation is 7115C.

[0882] <6A> The second filter 7116C reduces or removes the AC component contained in the second sum.

[0883] <7A> Calculate the square of the current detection value (I) for each phase separately.R 2 I S 2 I T 2 The third multiplication part of ) (7114R, 7114S, 7114T).

[0884] <8A> Calculate the squares (I) of the plurality of said squares. R 2 I S 2 I T 2 The third addition part of the third sum of ) 7115.

[0885] <9A> The third filter 7116 reduces or removes the AC component contained in the third sum.

[0886] <10A> Based on the output (F) of the first filter (7113R, 7113S, 7113T) R F S F T The output of the second filter 7116C (H) C ) and the output of the third filter 7116 (K C The abnormality levels of multiple current detectors are generated respectively, based on the output of the first filter (F). R F S F T ) and the output of the second filter 7116C (H C Anomaly calculation unit 7117 calculates the anomaly degree and judges the anomaly of the current detector based on the anomaly degree.

[0887] Inverter-side AC current detector anomaly detection unit 721

[0888] The inverter-side AC current detector anomaly detection unit 721 was also described in the power conversion device 100 of the first embodiment. However, since the description involves multiple aspects, some parts are repeated. But from the point of view of structure and function, it will be shown in a more organized manner below. The inverter-side AC current detector anomaly detection unit 721 is composed of <1B> to <10B> as described below.

[0889] <1B> Calculate the current detection values ​​(I) of multiple phases detected by multiple current detectors (34, 35, 36). U I V I W The first sum of I) I0 The first addition part 7211.

[0890] <2B> Calculate the first sum I for each of the multiple phases.I0 With current detection value (I) U I V I W The product of (D) is the first product (D) U D V D W The first multiplication part of ) (7212U, 7212V, 7212W).

[0891] <3B> Reduce or remove multiple first products (D) respectively. U D V D W The first filter (7213U, 7213V, 7213W) contains the AC component.

[0892] <4B> Calculate the product of two different current detection values, i.e., the second product (I). U I V I V I W I W I U The second multiplication part of ) (7214CW, 7214CU, 7214CV).

[0893] <5B> Calculate the second product (I) with respect to multiple second products U I V I V I W I W I U The second addition part of the second summation is 7215C.

[0894] <6B> The second filter 7216C reduces or removes the AC component contained in the second sum.

[0895] <7B> Calculate the square of the current detection value for each phase separately (I) U 2 I V 2 I W 2 The third multiplication part (7214U, 7214V, 7214W) of ).

[0896] <8B> Calculate with respect to the multiple squares (I) U 2 I V 2 I W 2 The third addition part of the third sum of ) 7215.

[0897] <9B> The third filter 7216 reduces or removes the AC component contained in the third sum.

[0898] <10B> Based on the output (F) of the first filter (7213U, 7213V, 7213W) U F V F W The output of the second filter 7216C (H) I ) and the output of the third filter 7216 (K I The abnormality levels of multiple current detectors are generated respectively, based on the output of the first filter (F). U F V F W ) and the output of the second filter 7216C (H I Anomaly calculation unit 7217 calculates the anomaly degree and judges the anomaly of the current detector based on the anomaly degree.

[0899] <Supplement to the AC current detector anomaly detection unit 711 on the converter side and the AC current detector anomaly detection unit 721 on the inverter side>

[0900] As described above, the structures of the converter-side AC current detector anomaly detection unit 711 (<1A> to <10A>) and the inverter-side AC current detector anomaly detection unit 721 (<1B> to <10B>) have been explained, but reference is made to... Figure 5 and Figure 6 It can be seen that the input signals and output signals of each part are different, but the AC current detector anomaly judgment unit 711 on the converter side and the AC current detector anomaly judgment unit 721 on the inverter side have the same structure.

[0901] Therefore, the AC current detector anomaly judgment unit 711 on the converter side and the AC current detector anomaly judgment unit 721 on the inverter side are sometimes appropriately referred to as "AC current detector anomaly judgment unit".

[0902] Alternating Current Detector Anomaly Detection Unit 731

[0903] Refer again Figure 17 The overall description of the abnormal judgment unit 731 of the AC current detector is provided.

[0904] exist Figure 17 In this paper, the output signals of the AC current detector anomaly judgment unit 711 on the converter side and the AC current detector anomaly judgment unit 721 on the inverter side are each represented by a single signal line, but in reality, multiple signals of the calculation process can be output.

[0905] For example, in the inverter-side AC current detector anomaly judgment unit 721, the detection gain (G) of the current detectors (34, 35, 36) is shown in equations (15), (16), and (17).U G V G W In that case, the signal is extracted. Similarly, the detection gain (G) of the current detectors (26, 27, 28) of the AC current detector anomaly judgment unit 711 on the converter side is also extracted. R G S G T () as a signal.

[0906] In addition, the detection gain (G) is also taken out in the inverter-side AC current detector anomaly judgment unit 721. U G V G W The average value of ) and the current amplitude (I) U I V I W The signal is the product of (third product) and (second product). Similarly, in the AC current detector anomaly judgment unit 711 on the converter side, the detection gain (G) is also extracted. R G S G T The average value of ) and the current amplitude (I) R I S I T The signal of the product of (the third product).

[0907] Additionally, in the inverter-side AC current detector anomaly judgment unit 721, as the output from the second filter 7216C, the second product (I) after calculating the reduction or removal of the AC component is also extracted. U I V I V I W I W I U The output signal of the second adder 7215C is used to calculate the second sum (I) after reducing or removing the AC component. Then, as the output of the third filter 7216, the third sum (I) is also taken out. U 2 I V 2 I W 2 The output signal of the third adder 7215.

[0908] Similarly, in the AC current detector anomaly judgment unit 711 on the converter side, as the output from the second filter 7116C, the second product (I) after calculating the reduction or removal of the AC component is also taken out. R I S I S I T I T I RThe output signal of the second adder 7115C is used to calculate the second sum (I) after reducing or removing the AC component. Then, as the output of the third filter 7116, the third sum (I) is also taken out. R 2 I S 2 I T 2 The output signal of the third adder 7115.

[0909] Furthermore, in the inverter-side AC current detector anomaly judgment unit 721, as the output from the first filter (7213U, 7213V, 7213W), a first sum I calculated for each of the multiple phases after reducing or removing the AC component is also taken out. I0 With current detection value (I) U I V I W The product of (D) is the first product (D) U D V D W The output signal of the first multiplication unit (7212U, 7212V, 7212W).

[0910] Similarly, in the AC current detector anomaly judgment unit 711 on the converter side, as the output from the first filter (7113R, 7113S, 7113T), the first sum I calculated for each of the multiple phases after reducing or removing the AC component is also taken out. C0 With current detection value (I) R I S I T The product of (D) is the first product (D) R D S D T The output signal of the first multiplication unit (7112R, 7112S, 7112T) of the )

[0911] exist Figure 17 In the middle, the output (K) of the second filter 7116C from the abnormal judgment unit 711 of the AC current detector on the converter side is input to the second arithmetic unit 7311. C ) and the output (H) from the third filter 7116 C ), (Third sum (I) R 2 I S 2 I T 2 Then, in the second arithmetic unit 7311, based on the output of the second filter 7116C on the converter side and the output of the third filter, a physical quantity equivalent to the product of the average detection gain of multiple current detectors and the current amplitude is calculated.

[0912] In addition, to Figure 17 The second arithmetic unit 7311 receives the output (K) of the second filter 7216C from the anomaly detection unit 721 on the inverter side. I ) and the output (H) from the third filter 7216 I ), (Third sum (I) U 2 I V 2 I W 2 Then, in the second operation unit 7311, based on the output of the second filter 7216C on the inverter side and the output of the third filter, a physical quantity equivalent to the product of the average value of the detection gain of multiple current detectors and the current amplitude is calculated.

[0913] Furthermore, in the second operation unit 7311, the operations on the converter side and the inverter side are performed independently.

[0914] exist Figure 17 In this process, the output signal of the second arithmetic unit 7311 is input to the storage unit 7312. Furthermore, the output signal of the second arithmetic unit 7311 may sometimes be the calculation result from the converter side and the calculation result from the inverter side, and these are processed separately.

[0915] In addition, there are signal S1 and signal S2 as other input signals for the storage unit 7312.

[0916] Signal S1 is AC power supply 1 ( Figure 1 The operating conditions on the ) side, signal S2 is for motor 4 ( Figure 1 Operating conditions on the side.

[0917] In principle, signal S1 is valid when the calculation result from the converter side is input to the storage unit 7312, and signal S2 is valid when the calculation result from the inverter side is input.

[0918] In the storage unit 7312, the average value of the detection gain and the third product of the current amplitude are stored in relation to the operating conditions of the AC power supply 1 or the motor (load device) 4.

[0919] The operating condition judgment unit 7313, equipped with the storage unit 7312, determines the operating conditions of the AC power supply 1 or the motor (load device) 4 based on the stored information in the storage unit 7312, outputs the operating condition output signal, and inputs it to the third arithmetic unit 7314.

[0920] The signal of the above-mentioned operation condition judgment unit 7313 (storage unit 7312) is input to the third arithmetic unit 7314.

[0921] Additionally, the third product of the average detection gain of multiple current detectors under normal conditions from the converter-side AC current detector anomaly judgment unit 711 and the inverter-side AC current detector anomaly judgment unit 721 and the current amplitude (converter side, inverter side) is input.

[0922] Furthermore, as needed, the outputs from the first filter (7113R, 7113S, 7113T), (7213U, 7213V, 7213W), and the output from the second filter 7116C (K) are combined. C ), 7216C(K I The output of ) comes from the third filter 7116 (H) C ), 7216(H I The output signals of each are input to the third arithmetic unit 7314.

[0923] The third calculation unit 7314 calculates the absolute anomaly degree of an absolute quantity representing multiple anomalies based on the third product, the physical quantity calculated by the second calculation unit under the same operating conditions as described above, the output of the first filter, the output of the second filter, and the output of the third filter.

[0924] The anomaly determination unit 7315, which includes a third arithmetic unit 7314, determines the anomalies of multiple current detectors based on the calculation results of the third arithmetic unit 7314.

[0925] <Effects of the Third Implementation Method>

[0926] In the power conversion device of the third embodiment, an operating condition judgment unit 7313 with a storage unit 7312 is provided. Therefore, the operating conditions of the AC power supply 1 or the motor (load device) 4 are taken into the abnormality judgment, so that the abnormality of the current detector can be accurately judged according to the actual situation.

[0927] Fourth Implementation Method

[0928] In the power conversion device of the first embodiment, such as Figure 1 As shown, an example is illustrated of using current detectors (26, 27, 28, 34, 35, 36) on a three-phase wiring line for current detection in AC power supply 1 or motor (load device) 4.

[0929] In the power conversion device 103 of the fourth embodiment, a method of using a shunt resistor in the inverter power conversion section for current detection will be described.

[0930] Figure 18 This is a diagram showing a structural example of the inverter power conversion section 31B of the power conversion device 103 according to the fourth embodiment of the present invention.

[0931] exist Figure 18 In the inverter power conversion section 31B of the inverter unit (3) of the power conversion device 103, the structure of the multiple IGBTs and capacitors constituting the inverter is similar to that of the inverter power conversion section 31B. Figure 1 same.

[0932] The difference is that the shunt resistors 34B, 35B, and 36B used for AC current measurement are respectively set on the N wiring 42 side of the power conversion section (31U, 31V, 31W) of each inverter, forming a circuit structure with a 3-shunt method as a current detector.

[0933] When the inverter power conversion unit (31U, 31V, 31W) operates and AC current flows through the shunt resistors 34B, 35B, and 36B respectively, each shunt resistor 34B, 35B, and 36B detects and measures the AC current of the U-phase, V-phase, and W-phase of the three-phase AC.

[0934] In this way, the configuration of the current detector is not limited to the inverter unit and motor 4, thus increasing the degree of freedom in the configuration of the inverter unit structure. In addition, depending on the situation, a reduction in manufacturing costs can be expected.

[0935] Alternatively, shunt resistors 34B, 35B, and 36B can be placed on the P wiring 40 side to detect AC current.

[0936] In addition to shunt resistors 34B, 35B, and 36B, and with Figure 2B as well as Figure 1 Since they are the same, other repeated descriptions are omitted.

[0937] In addition, Figure 18 The diagram shows a structural example where a shunt resistor is placed in the inverter power conversion section 31B, but... Figure 1 The three power conversion units (21R, 21S, 21T) of converter unit 2 in the middle. Figure 2A In the current detector, it can also replace current detectors 26, 27, and 28 and have a shunt resistor.

[0938] <Effects of the Fourth Implementation>

[0939] By using shunt resistors (34B, 35B, 36B), the range of installation locations for the current meter (current detector) can be expanded. Furthermore, depending on the situation, a reduction in manufacturing costs can be expected.

[0940] Other Implementation Methods

[0941] Furthermore, the present invention is not limited to the embodiments described above, and includes various modifications without departing from the spirit of the invention. For example, the embodiments described above are illustrative for ease of understanding of the present invention and are not limited to having all the structures described. In addition, a part of the structure of one embodiment can be replaced with a part of the structure of another embodiment, and it is also possible to add to, delete from, or replace a part or all of the structure of another embodiment with the structure of one embodiment.

[0942] Prevention and Response to Display Anomalies Based on Monitor 73

[0943] As described above, the first embodiment is explained Figure 1 The display (information prompt unit) 73 shown mainly displays judgment information related to the abnormality based on the output signals of the converter-side abnormality detector 71 and the inverter-side abnormality detector 72.

[0944] However, it is not limited to the judgment information at the detection time point of whether it is abnormal.

[0945] For example, information about the anomaly of the current detector and the phase difference can also be displayed on the display 73.

[0946] As a result, it is possible to anticipate the signs of anomalies in advance and to prepare for prevention and response when anomalies occur.

[0947] Alternatively, the occurrence of anomalies can be predicted as follows.

[0948] The system stores historical time-series data on the degree of anomaly. Based on this stored historical information, it predicts the period from the current time point until the degree of anomaly exceeds a pre-set threshold for anomaly judgment (e.g., a predetermined value α), i.e., until the anomaly occurs. The prediction result can also be displayed on the monitor 73.

[0949] As a result, it is possible to anticipate the signs of anomalies in advance and to prepare for prevention and response when anomalies occur.

[0950] Regarding the configuration of current detectors and anomaly detectors

[0951] In the first embodiment, a structure is described in which the current detectors 26, 27, and 28 are detected by the converter-side fault detector 71, and the current detectors 34, 35, and 36 are detected by the inverter-side fault detector 72.

[0952] However, it is not necessary to configure it on both the converter side and the inverter side as described above. It can also be configured to be located on either the converter side or the inverter side, depending on the situation. In this case, the anomaly detection method described in the above embodiments can also be applied.

[0953] "transistor"

[0954] In the power conversion devices 100 to 103 described above, the transistors constituting the power conversion section of the converter and the power conversion section of the inverter are described as IGBTs (Insulated Gate Bipolar Transistors).

[0955] However, transistors are not limited to IGBTs; they can also be MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) or superjunction MOSFETs.

[0956] Level Number of Power Conversion Devices

[0957] exist Figure 1 The first embodiment shown or Figure 15 In the second embodiment shown, a 3-level converter or a 2-level converter is used as an example.

[0958] However, the number of levels of the level converter is not limited to 3 levels or 2 levels. The anomaly detection processing of the current detector in this invention can also be applied to the anomaly detection of current detectors in all phases between the power converter and the power supply, or between the power converter and the load, in any multilevel converter (e.g., 5-level, 7-level).

[0959] Software and Hardware Processing

[0960] Regarding the processing performed by the converter-side fault detector 71, inverter-side fault detector 72, converter-side AC current estimation unit 712, and inverter-side AC current estimation unit 722, it is preferable that the processing is performed by a processor (not shown) executing software processing of a program stored in memory.

[0961] However, these structures are not limited to software-based processing; some or all of these processes can also be performed through hardware circuits.

[0962] The conversion objects of power conversion devices

[0963] exist Figure 1In the first embodiment shown, an AC-to-DC power converter (converter unit 2) or a DC-to-AC power converter (inverter unit 3) is used as an example, but it is not limited to this.

[0964] For example, an AC converter (e.g., transformer, AC-AC power converter) can be provided between the power source and the load to convert AC to AC.

[0965] Alternatively, an AC converter (e.g., a transformer) that converts AC voltage to AC can be installed between the power source and the power converter (converter unit 2).

[0966] Alternatively, an AC converter (e.g., a transformer) that converts AC voltage to AC can be installed between the power converter (inverter unit 3) and the load (motor 4).

[0967] It can also be applied to the abnormal detection of current detectors in all phases (e.g., 3 phases) configured between the power converter and the power source, or between the power converter and the load in the above structure.

[0968] Changes to filter settings

[0969] exist Figure 5 or Figure 6 In this device, the AC current detector anomaly detection unit (711, 721) includes a first filter, a second filter, and a third filter, but it is also advantageous to be able to change the setting of at least one of these filters. This provides an effect that easily adapts to desired characteristics and environments.

[0970] For example, as described above, when the current flowing through the current detector has a variable frequency due to reasons such as the variable operating frequency of the motor 4, the inverter-side AC current detector fault detection unit 721 is preferably configured to... Figure 6 The time constant (or cutoff frequency) of the filter used can be varied according to the operating frequency, so that even when the operating frequency of motor 4 is low, the AC component contained in the filter input can be removed to a greater extent.

[0971] The Fourth Filter

[0972] exist Figure 5 or Figure 6 In the AC current detector anomaly judgment unit (711, 721), a first filter, a second filter, and a third filter are provided. However, for at least one of a plurality of current detectors, a fourth filter is also provided to remove or reduce the DC component contained in the current detection value.

[0973] It has the characteristics of easily responding to expectations and environmental effects.

Claims

1. A power conversion device comprising at least one of a converter, an inverter, and an AC converter, wherein the converter converts AC to DC, the inverter converts DC to AC, and the AC converter converts AC to AC, characterized in that, The power conversion device includes: Multiple current detectors for detecting the AC current flowing between the AC power source and the power conversion device, or between the power conversion device and the load device, for each phase. An anomaly detector that identifies anomalies in multiple current detectors and anomalies in AC current caused by factors other than the current detectors. The anomaly detector has the following features: An AC current detector anomaly determination unit determines anomalies in the current detection values ​​of multiple phases detected by the multiple current detectors. The alternating current estimation unit calculates the current estimation value of the current detector based on the judgment result of the alternating current detector anomaly judgment unit. An AC current anomaly determination unit determines anomalies in the current detection values ​​of multiple phases detected by multiple current detectors based on the output of the AC current estimation unit.

2. The power conversion device according to claim 1, characterized in that, The anomaly detector consists of a converter-side anomaly detector configured on the AC power supply side and an inverter-side anomaly detector configured on the load device side. The AC current detector anomaly detection unit is composed of a converter-side AC current detector anomaly detection unit disposed on the converter-side anomaly detector and an inverter-side AC current detector anomaly detection unit disposed on the inverter-side anomaly detector. The AC current estimation unit consists of a converter-side AC current estimation unit disposed in the converter-side fault detector and an inverter-side AC current estimation unit disposed in the inverter-side fault detector. The AC current anomaly detection unit consists of a converter-side AC current anomaly detection unit installed in the converter-side anomaly detection unit and an inverter-side AC current anomaly detection unit installed in the inverter-side anomaly detection unit.

3. The power conversion device according to claim 1, characterized in that, In the anomaly detector, The AC current detector anomaly detection unit determines whether the current detector is abnormal. If the AC current detector anomaly determination unit detects an anomaly in the current detector, the output of the AC current estimation unit is switched to a predetermined estimation value. After a predetermined time, the AC current anomaly determination unit determines whether there is an AC current anomaly caused by something other than the current detector. If an abnormality is detected by the AC current abnormality determination unit, the AC current abnormality determination unit diagnoses the abnormality as being caused by an AC current detector malfunction or an AC current abnormality caused by factors other than the AC current detector. If the AC current anomaly detection unit does not detect any anomaly, the diagnosis is that the AC current detector is malfunctioning and the AC current is normal due to factors other than the AC current detector. If the AC current detector anomaly determination unit does not detect an anomaly in the current detector, the output of the AC current estimation unit is not switched, and the AC current anomaly determination unit determines that the AC current anomaly is caused by something other than the AC current detector. If the AC current anomaly detection unit detects an AC current anomaly, it diagnoses the problem as follows: the AC current detector is normal, and the AC current anomaly is caused by something other than the AC current detector. If the AC current anomaly judgment unit does not detect any AC current anomaly, it is diagnosed that the AC current detector is normal and the AC current caused by factors other than the AC current detector is normal.

4. The power conversion device according to claim 1, characterized in that, The anomaly detection unit of the AC current detector includes: The first addition unit calculates a first sum of the current detection values ​​of the multiple phases detected by the multiple current detectors; The first multiplication unit calculates the product of the first sum and the current detection value, i.e., the first product, for each of the plurality of phases; The first filter reduces or removes the AC components contained in the plurality of the first products, respectively; The second multiplication unit calculates the product of two different current detection values, i.e., the second product; The second addition part calculates the second sum with respect to multiple second products; The second filter reduces or removes the AC component contained in the second sum; The third multiplication unit calculates the square of the current detection value for each phase separately; The third addition unit calculates a third sum with respect to the squares of the plurality of said current detection values; The third filter reduces or removes the AC component contained in the third sum; An anomaly calculation unit generates multiple anomaly levels of the current detectors based on the outputs of the first filter, the second filter, and the third filter, and determines the anomaly of the current detectors based on the anomaly levels.

5. The power conversion device according to claim 4, characterized in that, The anomaly calculation unit further includes a first calculation unit that calculates multiple anomaly degrees, i.e., relative anomalies set in such a way that the sum of the multiple phases is always zero, based on the output of the first filter, the output of the second filter, and the output of the third filter. If the maximum value among the absolute values ​​of the plurality of relative anomalies is greater than a preset anomaly determination threshold, the AC current detector anomaly determination unit determines that at least one of the plurality of current detectors is abnormal.

6. The power conversion device according to claim 5, characterized in that, The AC current detector anomaly judgment unit determines whether it can classify the multiple relative anomalies into two elements with high similarity and one element with low similarity to these two elements. If classification is possible, it determines that only one of the multiple current detectors is abnormal. If classification is not possible, it determines that two or more current detectors are abnormal.

7. The power conversion device according to claim 4, characterized in that, The anomaly detection unit of the AC current detector includes: The storage unit stores the average value of the detection gain of the multiple current detectors under normal conditions and the third product of the current amplitude, in association with the operating conditions of the AC power supply or the load device. The second arithmetic unit calculates a physical quantity equivalent to the product of the average detection gain of the plurality of current detectors and the current amplitude, based on the outputs of the second filter and the third filter. The third calculation unit calculates the absolute anomaly degree of an absolute quantity representing the plurality of anomaly degrees based on the third product, the physical quantity calculated by the second calculation unit under the same operating conditions as the operating conditions, the output of the first filter, the output of the second filter, and the output of the third filter. The exception detection unit, which includes the third arithmetic unit, reflects the calculation result of the third arithmetic unit. The anomaly determination unit determines the anomalies of the multiple current detectors based on multiple absolute anomaly degrees.

8. The power conversion device according to claim 1, characterized in that, The AC current detector anomaly judgment unit includes: a first adder unit, which calculates a first sum of the current detection values ​​of multiple phases detected by the multiple current detectors. Based on the phase of the first sum and the phase of the current detection values ​​of the multiple phases detected by the multiple current detectors, the AC current detector anomaly determination unit determines the anomaly of the current detector.

9. The power conversion device according to claim 1, characterized in that, If the AC current anomaly determination unit determines that the current detector is abnormal, the AC current estimation unit estimates the current detection value of the current detector that was determined to be abnormal when it is in normal operation, based on the current detection value of the current detector that was not determined to be abnormal. The operation continues based on the current detection value of the current detector that is not judged as abnormal and the current detection value estimated by the AC current estimation unit.

10. The power conversion device according to claim 4, characterized in that, When the AC current anomaly determination unit determines that the current detector is abnormal, the AC current estimation unit estimates the current detection value assumed to be normal for the current detector based on the relative or absolute anomaly degree of the multiple current detectors and the current detection values ​​of the multiple current detectors. Instead of the current detection value of the current detector, the system continues to operate based on multiple current detection values ​​estimated by the AC current estimation unit.

11. The power conversion device according to claim 1, characterized in that, The AC current anomaly judgment unit calculates at least one of the effective value, amplitude, and phase difference of the output of the AC current estimation unit, compares at least one of the effective value, amplitude, and phase difference with a predetermined value, and determines whether the AC current caused by factors other than the current detector is normal or abnormal.

12. The power conversion device according to claim 1, characterized in that, The AC current anomaly judgment unit calculates the standardized phase difference of the AC current of multiple phases. If the minimum value of the multiple standardized phase differences is greater than a predetermined value, it is judged that the current of each phase is normal. If the minimum value of the multiple standardized phase differences is less than the predetermined value, it sequentially compares the minimum value of the multiple standardized phase differences with the standardized phase difference of each phase. If the minimum value of the multiple standardized phase differences is equal to the predetermined standardized phase difference of the phase, it is judged that the current amplitude of that phase is the largest, and it is judged that the risk of local short circuit or three-phase imbalance of that phase is high.

13. The power conversion device according to claim 1, characterized in that, The AC current anomaly detection unit detects the amplitude of AC current in multiple phases and calculates the estimated amplitude value for each phase based on the amplitude. If the maximum value of the multiple estimated amplitude values ​​is less than or equal to a predetermined value, the current in each phase is judged to be normal. If the maximum value of the multiple estimated amplitude values ​​is greater than the predetermined value, the maximum value of the multiple estimated amplitude values ​​is compared with the estimated amplitude value of each phase in turn. If the maximum value of the multiple estimated amplitude values ​​is equal to the predetermined estimated amplitude value of the phase, the current amplitude of that phase is judged to be the largest, and the risk of local short circuit or three-phase imbalance in that phase is judged to be high.

14. The power conversion device according to claim 4, characterized in that, The filter settings of at least one of the first filter, the second filter, and the third filter are changed according to the frequency of the alternating current flowing through the multiple current detectors.

15. The power conversion device according to claim 4, characterized in that, The AC current detector anomaly detection unit further includes: a fourth filter, which removes or reduces the DC component contained in the current detection value for at least one of the plurality of current detectors. The output of the fourth filter is used instead of the current detection value.

16. The power conversion device according to claim 1, characterized in that, The power conversion device includes an information prompting unit that displays abnormal information. The anomaly detector generates historical information on multiple anomaly levels, predicts the period until the anomaly of the current detector occurs based on the historical information, and uses the prediction result as the anomaly information and prompts the information prompt unit.

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