Rotary machine control device

Abstract

A rotating machine control device (1) for applying an AC voltage to a rotating machine (16) by passing a DC voltage from a DC power source (13) through a power converter (14), the rotating machine control device (1) being provided with: a voltage command generator (10) for generating a voltage command value; a carrier generation unit (11); and a comparator (12) that determines the switching operation of the power converter on the basis of the voltage command value and the output of the carrier wave generation unit, the carrier wave generation unit (11) having a carrier wave corrector (20) that corrects the frequency of the carrier wave, and the carrier wave generation unit (11) is configured so that the number of switching times per electrical angle period is not increased as much as possible. Switching is performed so that the peak current in a region in which the magnitude of the current value in the current information of the rotating machine (16) is greater than a predetermined magnitude does not increase, whereby the increase in the peak current is suppressed without increasing loss associated with the switching operation, and the rotating machine (16) and the power converter (14) are protected.

Description

Technical Field

[0001] The present application relates to a rotating machinery control device. Background Art

[0002] In rotating machinery control devices, synchronous PWM control is commonly used to achieve symmetry in voltage pulses within a single electrical angle cycle when performing pulse width modulation (PWM) control of rotating machinery in high-speed ranges. Triangular wave comparison synchronous PWM control, which determines the PWM duty cycle by comparing a triangular wave with a modulation signal, has gained widespread popularity due to its simple structure and ability to ensure voltage pulse symmetry.

[0003] On the other hand, in order to reduce the losses associated with switching actions, it is preferable to reduce the number of switching actions as much as possible. Here, the number of switching actions is defined as the sum of the switching actions, that is, the actions of connecting and disconnecting, performed by the power converter per one electrical angle cycle. For example, in the case of synchronous 9P, the number of switching actions is 18 times. In the case of synchronous 6P, the number of switching actions is 12 times. When the number of switching times is reduced, the voltage harmonics and current harmonics increase, and there is a problem of an increase in the peak value of the phase current (hereinafter referred to as peak current). In the case of applications such as FA (Factory Automation), air conditioners, machine tools, aircraft, railways or automobiles that use rotating machinery control devices, if the increase in peak current cannot be fully suppressed, demagnetization and component damage will occur. Therefore, it is expected to achieve a reduction in the number of switching times and the peak current at the same time.

[0004] For example, Patent Document 1 utilizes a triangular wave comparison-based asynchronous PWM control structure to increase the carrier frequency in regions where the phase current amplitude increases, thereby suppressing increases in peak current. Furthermore, Patent Document 2 utilizes a triangular wave comparison-based synchronous PWM control structure to suppress increases in electromagnetic noise by making the carrier frequency of a specific carrier cycle an integer multiple, and ensuring that the period of the integer multiple does not span two cycles.

[0005] Prior art literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2-168895

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2012-235619 Summary of the Invention

[0008] However, the structures of Patent Documents 1 or 2 present the following problem: even if the increase in peak current can be suppressed, the number of switching cycles will increase. Furthermore, the limited number of patterns that can be handled as carrier shapes makes suppressing the increase in peak current less effective. Furthermore, increasing the carrier frequency and the number of switching cycles to reduce peak current increases the heat generated by the inverter chips, which serve as switching elements, and can cause inverter failure.

[0009] The present application discloses a technology for solving the above-mentioned problems, and its object is to suppress an increase in peak current without increasing the loss associated with switching operation, thereby protecting a rotating machine and a power converter.

[0010] The rotary machine control device disclosed in the present application is a device for applying an AC voltage to the rotary machine by passing a DC voltage from a DC power supply through a power converter. The device is characterized by comprising: a voltage command generator for generating a voltage command value; a carrier generator for generating a carrier; and a comparator for determining a switching operation of the power converter based on the voltage command value and an output of the carrier generator. The carrier generator includes a carrier corrector for correcting the frequency of a reference carrier. The carrier corrector corrects the frequency of the reference carrier so that the frequency of the carrier is greater than 1.0 times in at least a portion of a region where the magnitude of the current value in the current information of the rotary machine is greater than a predetermined magnitude, and corrects the frequency of the carrier so that the frequency is less than 1.0 times in at least a portion of a region where the magnitude of the current value in the current information of the rotary machine is less than a predetermined magnitude. Alternatively, the carrier corrects the frequency of the carrier so that the frequency is greater than 1.0 times in at least a portion of a region where the magnitude of the current value in the current information of the rotary machine is greater than the predetermined magnitude, and corrects the frequency of the carrier so that the frequency is less than 1.0 times in at least a portion of a region where the magnitude of the current value in the current information of the rotary machine is less than the predetermined magnitude.

[0011] According to the rotating machinery control device disclosed in the present application, switching is performed in a manner that does not increase the peak current in the area where the current value in the current information of the rotating machinery is greater than a predetermined value, under the condition that the number of switching times per electrical angle cycle is minimized, thereby suppressing the increase in peak current without increasing the loss associated with the switching action, thereby protecting the rotating machinery and the power converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a hardware configuration diagram of the rotating machine control device according to the first embodiment.

[0013] Figure 2 This is a functional block diagram of the rotating machine control device according to the first embodiment.

[0014] Figure 3 This is a block diagram illustrating the internal structure of the carrier wave generating unit according to the first embodiment.

[0015] Figure 4 This is a block diagram illustrating the internal structure of the carrier calibrator according to the first embodiment.

[0016] Figure 5 This is a block diagram illustrating the internal structure of the carrier arithmetic unit according to the first embodiment.

[0017] Figure 6 1 is a diagram illustrating a carrier wave generated by a rotating machine control device according to a comparative example.

[0018] Figure 7 This is a diagram illustrating a carrier obtained by correcting the carrier frequency of the rotating machine control device according to the first embodiment.

[0019] Figure 8 This is a diagram illustrating a carrier obtained by correcting the carrier frequency and carrier phase of the rotating machine control device according to the first embodiment.

[0020] Figure 9 This is a diagram illustrating a carrier obtained by correcting the carrier frequency and carrier phase when there is a large phase difference between the voltage and the current in the rotating machine control device according to the first embodiment. DETAILED DESCRIPTION

[0021] Hereinafter, preferred embodiments of the rotary machine control device according to the present application will be described with reference to the accompanying drawings. The same reference numerals are assigned to the same contents and corresponding parts, and their detailed description will be omitted.

[0022] Implementation method 1.

[0023] Figure 1 An example of the hardware of the rotating machine control device 1 of the present application is shown. It includes a processor 2 and a storage device 3. Although not shown, the storage device 3 includes a volatile storage device such as a random access memory and a non-volatile auxiliary storage device such as a flash memory. Alternatively, an auxiliary storage device such as a hard disk may be included in place of the flash memory.

[0024] Figure 2 This is a functional block diagram of a rotating machine control device according to this embodiment. The rotating machine control device 1 includes a voltage command generator 10, a carrier generator 11, and a comparator 12. Comparator 12 transmits a gate signal that controls the on / off switching of a power converter 14. The voltage from a DC power supply 13 is converted into an AC voltage, which is then applied to a rotating machine 16 to drive the rotating machine 16. The following describes the various components within the rotating machine control device 1 in detail.

[0025] The voltage command generator 10 generates a voltage command value, a voltage phase, a rotational speed, a pulse number, and a torque command based on the input action command and current information. Here, the action command refers to the command torque, command rotational speed, and current command input from the outside to the voltage command generator. Current information is detected from the current of each phase of the rotating machine 16. As described later, the current information can also use the current detection value or current command value detected by the current detector 15, or the current estimation value estimated or predicted from the characteristics of the rotating machine. The generated voltage command value is output to the comparator 12. In addition, the generated voltage phase, rotational speed, pulse number, and torque command are output to the carrier generator 11. Current information is also input to the carrier generator 11. In addition, the voltage phase can also be included as part of the information of the voltage command value.

[0026] As a method for generating voltage command values, for example, three-phase voltage command values ​​can be obtained by converting motion commands into current commands and controlling the current vector on rotating coordinates (dq coordinates). Alternatively, three-phase voltage command values ​​corresponding to the commanded rotational speed can be obtained, as in constant V / f control.

[0027] Although not shown, the voltage phase is obtained based on the rotor position detected or estimated using a resolver or encoder as a position detector mounted on the rotating machine 16 and the phase of the voltage vector obtained from the three-phase voltage command values.

[0028] The rotation speed uses a value calculated from the rotor position or a value detected by a speed detector.

[0029] The number of pulses represents the number of voltage pulses that perform switching actions in one electrical angle cycle, and is also the number of carrier waves. The number of carrier waves is the number of cycles of the carrier wave in one electrical angle cycle. When the carrier wave is a triangular wave, it is equal to the number of peaks or troughs. The number of pulses is determined based on at least the rotational speed, and is determined by the sound, higher harmonics, torque, vibration, and operation cycle associated with the switching. As the number of pulses, odd numbers such as 15, 9, 5, and 3 are often selected based on the symmetry of the pulse waveform, but even numbers such as 12 and 6 can also be selected. When managing the number of pulses during multiple electrical angle cycles, numbers containing decimals can also be selected. For example, when 15.1, 9.8, or 6.5 are selected as the number of pulses in one electrical angle cycle, the number of pulses in 10 electrical angle cycles becomes 151, 98, or 65.

[0030] The carrier generator 11 includes a carrier corrector 20 and a carrier calculator 30, and generates a carrier wave based on the voltage phase, rotational speed, pulse count, torque command, and current information generated by the voltage command generator 10. The generated carrier wave is output to the comparator 12. The frequency of the carrier wave is generated by multiplying the frequency of the voltage command value by a factor.

[0031] Comparator 12 compares the magnitude of the voltage command value generated by voltage command generator 10 and the carrier generated by carrier generator 11 to generate a PWM waveform and output a gate signal to power converter 14. Specifically, comparator 12 determines the switching operation of power converter 14 based on the voltage command value and the carrier.

[0032] The gate signal output from the comparator 12 of the rotating machine control device 1 is input to the power converter 14. The power converter 14 is connected to the DC power supply 13 and the rotating machine 16 via wiring. The power converter 14 converts the DC voltage of the DC power supply 13 into an AC voltage based on the gate signal and applies it to the rotating machine 16. Naturally, when the rotational speed approaches zero, the AC current and AC voltage become DC current and DC voltage. If an offset component is included, the AC current and AC voltage will contain not only the AC component but also a DC component.

[0033] The current detector 15 detects the currents iu, iv, and iw of the U-phase, V-phase, and W-phase of the rotating machine 16. Furthermore, instead of the current detected by the current detector 15, a current estimator that predicts or estimates the current based on the current command values ​​of a portion or all of the phases, or the rotating machine characteristics shown in the following equation (1) may be used. Alternatively, a configuration may be employed that detects the current on the DC bus side and calculates the current of each phase. There are cases where a current estimator is used in place of the current detector 15 to reduce costs. However, even when the accuracy and response of the current detector 15 are low, using a current estimator instead allows for reliable observation of transiently changing currents.

[0034] [Mathematical formula 1]

[0035]

[0036] Here, equation (1) is the voltage equation at the fixed coordinates u, v, and w of the rotating machine, vu, vv, and vw represent the phase voltages, R represents the winding resistance, s represents the differential operator, Lu, Lv, and Lw represent the self-inductance of each winding, Muv, Mvw, and Mwu represent the mutual inductance between the windings, iu, iv, and iw represent the phase currents, ωre represents the electrical angular velocity, φmag represents the permanent magnet flux, and θre represents the electrical angular position.

[0037] The rotating machine 16 is conceived as a three-phase synchronous motor or a three-phase induction motor. However, it may also be a motor other than a three-phase motor, such as a dual three-phase winding motor or a five-phase motor, or a field winding type motor. It may also be configured with other types of synchronous reluctance motors, switched reluctance motors, other synchronous motors, or induction motors.

[0038] Figure 3 2 is a block diagram illustrating the configuration of the carrier wave generator 11. The carrier wave generator 11 includes a carrier wave corrector 20 and a carrier wave calculator 30.

[0039] The carrier corrector 20 calculates a carrier frequency correction value and a carrier phase correction value based on the voltage phase, rotation speed, and torque command information generated by the voltage command generator 10 and the current information from the current detector 15 , and outputs the values ​​to the carrier calculator 30 .

[0040] The carrier calculator 30 generates a carrier wave by correcting a reference carrier wave based on the voltage phase, rotational speed, and pulse count generated by the voltage command generator 10, using the carrier frequency correction value and carrier phase correction value calculated by the carrier corrector 20. The reference carrier wave has a carrier frequency that is constant over one electrical angle period.

[0041] Figure 4 2 is a block diagram illustrating the internal structure of the carrier corrector 20. The carrier corrector 20 includes a carrier frequency correction value calculator 21, a carrier phase correction value calculator 22, a correction determiner 23, and multipliers 24 and 25.

[0042] The carrier frequency correction value calculator 21 calculates the carrier frequency correction value based on the voltage phase. This correction is performed by increasing or decreasing the carrier frequency to prevent a change of more than 20% without changing the number of switching cycles (equivalent to the number of pulses or carrier waves) per electrical angle period.

[0043] That is, for the frequency of the carrier wave that serves as the reference,

[0044] Correction is performed so that the frequency of the carrier wave is greater than 1.0 in at least a portion of a region where the magnitude of the current value in the current information of the rotating machine 16 is greater than a predetermined magnitude, and correction is performed so that the frequency of the carrier wave is less than 1.0 in at least a portion of a region where the magnitude of the current value in the current information of the rotating machine 16 is less than a predetermined magnitude.

[0045] or,

[0046] Correction is performed in a manner such that the frequency of the carrier becomes greater than 1.0 times in at least a portion of the region where the magnitude of the current value in the current information of the rotating machine 16 is greater than a predetermined magnitude, and correction is performed in a manner such that the frequency of the carrier becomes less than 1.0 times in at least a portion of the region where the magnitude of the current value in the current information of the rotating machine 16 is less than a predetermined magnitude.

[0047] Or, for the frequency of the carrier wave that serves as the reference,

[0048] Correction is performed so that the frequency of the carrier wave is greater than 1.0 in at least a portion of a region where the magnitude of the voltage command value of the rotating machine 16 is greater than a predetermined magnitude, and correction is performed so that the frequency of the carrier wave is less than 1.0 in at least a portion of a region where the magnitude of the voltage command value of the rotating machine 16 is less than a predetermined magnitude.

[0049] or,

[0050] Correction is performed in a manner such that the frequency of the carrier becomes greater than 1.0 times in at least a portion of the region where the magnitude of the voltage command value of the rotating machine 16 is greater than a predetermined magnitude, and correction is performed in a manner such that the frequency of the carrier becomes less than 1.0 times in at least a portion of the region where the magnitude of the voltage command value of the rotating machine 16 is less than a predetermined magnitude.

[0051] Specifically, in the case of the present embodiment, in the region where the amplitude of the AC waveform as the current information becomes large, the carrier frequency of the carrier wave that will serve as the reference is corrected to be higher in such a manner that the peak current becomes smaller. The region where the amplitude of the current information becomes large refers to the region where the instantaneous value of the current information (AC waveform) becomes greater than a predetermined value of any positive or negative peak value. For example, it is greater than 90% of the peak value. The reason for setting it as at least a part of the region is that there is no need to increase the carrier frequency of the entire interval of the region where the amplitude of the current information becomes large, and it can be corrected in such a manner that the effect of reducing the peak current becomes higher. In addition, the same is true when a voltage command value is used instead of the current information. When a voltage command value is used, the voltage command value from the voltage command generator 10 is input to Figure 2 The carrier wave generating unit 11.

[0052] Thus, under the condition that the number of switching times per electrical angle cycle is minimized, switching is performed in a manner that does not increase the peak current in the area where the current value in the current information of the rotating machinery is greater than a predetermined value, or switching is performed in a manner that does not increase the peak current in the area where the voltage command value of the rotating machinery is greater than a predetermined value. This allows the increase in peak current to be suppressed without increasing the loss associated with the switching action, thereby protecting the rotating machinery and the power converter.

[0053] Simply increasing the carrier frequency will increase the number of switching cycles per electrical angle cycle. Therefore, in areas where peak current is not a problem, the carrier frequency of the reference carrier is lowered to correct the frequency of switching cycles, preventing it from increasing or varying by more than 20% per electrical angle cycle. This reduces switching losses. The reason for preventing variations of more than 20% is that, while the number of pulses is typically controlled using values ​​such as 21, 15, 12, 9, or 6, increasing the number of switching cycles by 20% when controlling with a pulse number of 12, for example, results in the same number of switching cycles as when controlling with a pulse number of 15, thus minimizing the effect of not increasing the number of switching cycles.

[0054] The implementation method is achieved by pre-storing a correction pattern that reduces the peak current without increasing the number of switching cycles for each operating point as a map or function. While the carrier frequency correction value calculator 21 is configured to calculate the correction value based on the voltage phase as described above, it can also be implemented based on the current phase, rotor position, or other factors instead of the voltage phase.

[0055] The carrier phase correction value calculator 22 corrects the carrier phase based on the rotational speed and torque command to achieve a carrier phase that reduces the peak current. Specifically, it calculates the carrier phase correction value by using a map or function based on the operating point to maintain the carrier phase at which the peak current is reduced. While the carrier phase correction value calculator 2 calculates the correction value based on the rotational speed and torque command, it can also be configured to calculate the correction value based on voltage command values, current information, and so on. This allows the switching phase to be adjusted to improve the effect of suppressing increases in peak current.

[0056] The carrier frequency correction value and carrier phase correction value are designed not only to reduce peak current but also to ensure PWM pulse symmetry as much as possible. Specifically, the PWM pulses between voltage phases 0 to 180 degrees and 180 to 360 degrees are designed to be point-symmetrical. If possible, the PWM pulses between 0 to 90 degrees and 90 to 180 degrees, and between 180 to 270 degrees and 270 to 360 degrees are preferably designed to be line-symmetrical as well.

[0057] The correction determiner 23 determines whether the correction values ​​of the carrier frequency correction value calculator 21 and the carrier phase correction value calculator 22 have been corrected based on an operating point such as a rotational speed, a torque command, or a voltage command, or a peak current calculated based on information on the current actually flowing through the rotating machine 16. For example, in a case where the peak current is close to an operating point where it becomes a problem, or when the peak current is closer to the overcurrent threshold than expected, a "1" is output, for example, to correct the carrier frequency or phase. Conversely, in a case where the peak current is not a problem at an operating point, or when the peak current is not closer to the overcurrent threshold than expected, a "0" is output, for example, to not correct the carrier frequency and phase. In this way, by applying only to specific operating points, it is not necessary to perform corrections at all operating points, and the control structure can be simplified.

[0058] Multiplier 24 multiplies the output of carrier frequency correction value calculator 21 by the output of correction determiner 23. Multiplier 25 determines the carrier frequency correction value and carrier phase correction value by multiplying the output of carrier phase correction value calculator 22 by the output of correction determiner 23. Although multipliers are used here, other structures (e.g., functions or maps) such as adders and subtractors or dividers may be used instead of multipliers.

[0059] In addition, in this structure, the carrier frequency and phase are corrected in a manner such that the peak current becomes smaller, but it is also possible to have a structure in which the carrier frequency and phase are corrected in a manner such that current harmonics, voltage harmonics, vibration, and heat are reduced in addition to the peak current.

[0060] Figure 5 3 is a block diagram illustrating the internal structure of the carrier calculator 30. The carrier calculator 30 includes multipliers 31 and 32, an adder 33, and a carrier generator 34.

[0061] Multiplier 31 multiplies the rotational speed and pulse count generated by voltage command generator 10 to calculate a base carrier frequency. Multiplier 32 multiplies the carrier frequency output by multiplier 31 by the carrier frequency correction value calculated by carrier frequency correction value calculator 21 to output the carrier frequency. The base carrier frequency is a carrier frequency that remains constant within one electrical angle cycle. Instead of multiplier 31, another structure (e.g., a function or map) such as an adder-subtractor or divider may be used. The base carrier frequency is a coefficient times the frequency of the voltage command value. When the carrier frequency correction value is multiplied by multiplier 32, the frequency is further multiplied by the coefficient.

[0062] Adder 33 adds the voltage phase generated by voltage command generator 10 and the carrier phase correction value calculated by carrier phase correction value calculator 22, and outputs a carrier phase synchronized with the voltage phase. Adder 33 may be replaced with another structure (e.g., a function or map) such as a subtractor, divider, or multiplier.

[0063] The carrier generator 34 generates and outputs a carrier wave synchronized with the voltage phase based on the carrier frequency output by the multiplier 32 and the carrier phase output by the adder 33. A triangular wave is often used as the carrier wave, but a sawtooth wave, a sine wave, or a rectangular wave may also be used.

[0064] Figure 6 The following diagram shows the voltage command value, current, carrier wave, and carrier frequency of a comparative rotating machine control device that does not include the carrier corrector 20. This example uses a triangular wave as the carrier wave and a pulse count of 9. The voltage command value is synchronized with the carrier wave, and the carrier frequency is constant.

[0065] In this comparative example, PWM pulses are generated by comparing the magnitude of the carrier and the voltage command value. The voltage command value is set to a binary value: H (High) when the voltage command value is greater than the carrier, and L (Low) when the voltage command value is less than the carrier. In this case, the PWM pulse is high for a certain period near the positive peak of the current, and low for a certain period near the negative peak. Specifically, the PWM pulse is high near the positive peak of the current, commanding a positive increase in the current. Near the negative peak, the PWM pulse is low, commanding a negative increase in the current, increasing the peak current.

[0066] In contrast, Figure 7 The voltage command value, current, carrier wave, and carrier wave frequency of the rotary machine control device 1 according to this embodiment are shown. Figure 6 , shows an example of a case where the carrier frequency is corrected by the carrier corrector 20. At this time, in a part of the region where the current value of the phase current is large, that is, in the region around 70 degrees to 110 degrees and 250 degrees to 290 degrees, which is plus or minus 20 degrees including the peak, the carrier frequency is doubled, so that Figure 6In comparison, the interval in which the PWM pulse becomes high near the positive peak of the current (approximately 80 degrees to approximately 100 degrees) and the interval in which the PWM pulse becomes low near the negative peak of the current (approximately 260 degrees to approximately 280 degrees) can be shortened, thereby suppressing the increase in peak current. On the other hand, in a portion of the region where the current value decreases, that is, in the present embodiment, in the regions outside the above-mentioned regions, the regions of 10 degrees to 70 degrees, 110 degrees to 170 degrees, 190 degrees to 250 degrees, and 290 degrees to 350 degrees, the carrier frequency is reduced to 0.6 times, so the number of pulses in one electrical angle cycle and the number of carriers do not change. By using such a correction method, the peak current can be reduced without increasing the number of switching times. In addition, the selection of the region in which the current value increases when the carrier frequency is increased and the selection of the degree to which the frequency is increased are not limited to this example, as long as it is a method that can suppress the increase in peak current.

[0067] exist Figure 8 In, relative to Figure 7 The structure of FIG shows an example of a case where not only the carrier frequency but also the carrier phase is corrected. In this case, the correction of the carrier frequency is the same as Figure 7 Same, but relative to Figure 7 , the carrier phase is corrected by 180 degrees. Figure 8 Correcting the carrier phase as shown, thereby increasing the carrier frequency region even with Figure 7 Similarly, the PWM pulse is set to low in a certain interval near the positive peak of the current (in this embodiment, it is centered around 90 degrees and a few degrees before and after), and the PWM pulse is set to high in a certain interval near the negative peak of the current (in this embodiment, it is centered around 270 degrees and a few degrees before and after). This utilizes the principle that when the PWM pulse is high, the current changes in the direction of increase, and when the PWM pulse is low, the current changes in the direction of decrease. Figure 7 Compared with the carrier phase correction Figure 8 In this case, the peak current can be reduced. By correcting not only the carrier frequency but also the carrier phase, the peak current reduction effect can be further improved. The angles listed here are just examples.

[0068] Figure 9 An example of correcting the carrier frequency and carrier phase when the phase difference between voltage and current is large, for example, when the phase difference is 50 degrees, is shown. Figure 8 Similarly, near the peak of the current, Figure 9The carrier frequency is corrected to increase within the 70-degree range (80 to 150 degrees, 260 to 330 degrees) encompassing the peak, and to decrease in the remaining ranges. The carrier phase is also corrected to achieve a low PWM pulse in a certain interval near the positive peak of the current (in this embodiment, approximately a few degrees around 130 degrees) and a high PWM pulse in a certain interval near the negative peak of the current (in this embodiment, approximately a few degrees around 310 degrees), thereby enhancing the peak current reduction effect. The angles listed here are merely examples.

[0069] exist Figure 7 、 Figure 8 、 Figure 9 In the timing of the peak or trough of the carrier, the carrier frequency is corrected, but the carrier frequency can also be corrected at other timings. The correction value of the carrier frequency and phase is an example, so it can also be set to Figure 7 、 Figure 8 、 Figure 9 Values ​​other than those listed.

[0070] In addition, Figure 7 、 Figure 8 In the PWM waveform, the voltage phase between 0 degrees and 180 degrees and 180 degrees and 360 degrees is made point-symmetrical to suppress the occurrence of offset and even-numbered higher harmonics, and the voltage pulses between 0 degrees and 90 degrees and 180 degrees, 180 degrees and 270 degrees and 360 degrees are made line-symmetrical to express a sine wave waveform. Figure 9 In the embodiment, the PWM pulse waveforms between the voltage phases 0 to 180 degrees and 180 to 360 degrees are designed to be point symmetrical for the same reasons as above. However, the carrier frequency and phase may be corrected without maintaining the symmetry.

[0071] in addition, Figure 7 、 Figure 8 、 Figure 9 The correction value of the carrier frequency becomes a secondary component in one electrical angle period, but can also become a tertiary component and so on and be set so that the carrier shapes among the three phases are the same.

[0072] This application describes exemplary embodiments, but the various features, methods, and functions described in the embodiments are not limited to the application of specific embodiments and can be applied to the embodiments individually or in various combinations. Therefore, within the scope of the technology disclosed in this specification, countless unillustrated variations are conceivable. For example, this includes the case where at least one component is deformed, at least one component is added, or at least one component is omitted.

[0073] Explanation of symbols

[0074] 1: Rotating machinery control device; 2: Processor; 3: Storage device; 10: Voltage command generator; 11: Carrier generator; 12: Comparator; 13: DC power supply; 14: Power converter; 15: Current detector; 16: Rotating machinery; 20: Carrier corrector; 21: Carrier frequency correction value operator; 22: Carrier phase correction value operator; 23: Correction determiner; 24, 25: Multipliers; 30: Carrier operator; 31, 32: Multipliers; 33: Adder; 34: Carrier generator.

Claims

1. A rotating machine control device, which applies an AC voltage to the rotating machine by passing a DC voltage of a DC power supply through a power converter, characterized in that: The rotary machine control device comprises: a voltage command generator that generates a voltage command value; a carrier wave generator that generates a carrier wave; and a comparator that determines a switching operation of the power converter based on the voltage command value and an output of the carrier wave generator. The carrier wave generating unit includes a carrier wave corrector for correcting the frequency of a carrier wave serving as a reference. The carrier corrector is used for the frequency of the carrier wave used as the reference. Correction is performed so that the frequency of the carrier wave is greater than 1.0 times in at least a portion of a region where the magnitude of the current value in the current information of the rotating machine is greater than a predetermined magnitude, and correction is performed so that the frequency of the carrier wave is less than 1.0 times in at least a portion of a region where the magnitude of the current value in the current information of the rotating machine is less than the predetermined magnitude, or, Correction is performed in a manner that causes the frequency of the carrier to be greater than 1.0 times, at least in a portion of an area where the magnitude of the current value in the current information of the rotating machinery is greater than the predetermined magnitude, and correction is performed in a manner that causes the frequency of the carrier to be less than 1.0 times, at least in a portion of an area where the magnitude of the current value in the current information of the rotating machinery is less than the predetermined magnitude.

2. A rotating machine control device, which applies an AC voltage to the rotating machine by passing a DC voltage of a DC power supply through a power converter, characterized in that: The rotary machine control device comprises: a voltage command generator that generates a voltage command value; a carrier wave generator that generates a carrier wave; and a comparator that determines a switching operation of the power converter based on the voltage command value and an output of the carrier wave generator. The carrier wave generating unit includes a carrier wave corrector for correcting the frequency of a carrier wave serving as a reference. The carrier corrector is used for the frequency of the carrier wave used as the reference. Correction is performed so that the frequency of the carrier wave is greater than 1.0 times in at least a portion of a region where the magnitude of the voltage command value of the rotating machine is greater than a predetermined magnitude, and correction is performed so that the frequency of the carrier wave is less than 1.0 times in at least a portion of a region where the magnitude of the voltage command value of the rotating machine is less than the predetermined magnitude, or, Correction is performed in a manner that causes the frequency of the carrier to be greater than 1.0 times, at least in a portion of the region where the magnitude of the voltage command value of the rotating machine is greater than the predetermined magnitude, and correction is performed in a manner that causes the frequency of the carrier to be less than 1.0 times, at least in a portion of the region where the magnitude of the voltage command value of the rotating machine is less than the predetermined magnitude.

3. The rotating machine control device according to claim 1 or 2, characterized in that: The carrier corrector corrects the frequency of the carrier so that the number of switching operations in one electrical angle period becomes constant, or at least the number of switching operations does not change by 20% or more compared with before correction.

4. The rotating machine control device according to any one of claims 1 to 3, characterized in that: The carrier corrector corrects the phase of the carrier in such a way that the phase difference between the voltage command value and the carrier changes based on at least one parameter of the rotation speed of the rotating machine, a torque command, a voltage command value, and current information of the rotating machine.

5. The rotating machine control device according to any one of claims 1 to 4, characterized in that: The carrier corrector has a correction determiner for determining whether to correct the frequency and phase of the carrier, and determines whether to correct the correction based on at least one parameter of the rotating machine's rotation speed, torque command, voltage command value, and current information of the rotating machine.

6. The rotating machine control device according to any one of claims 1 to 5, characterized in that: The carrier generating unit has a carrier operator that operates the carrier based on the reference carrier frequency that is a coefficient times the frequency of the voltage command value and a correction value of the carrier corrector, wherein the reference carrier frequency is a carrier frequency calculated based on the rotation speed of the rotating machine and the number of pulses determined based on the rotation speed.

7. The rotating machine control device according to any one of claims 1 to 6, characterized in that: The current information of the rotating machine uses a current detection value detected by a current detector, a current command value, or a current estimation value estimated or predicted based on the rotating machine characteristics of the rotating machine.

8. The rotating machine control device according to claim 1 or 2, characterized in that: The region larger than the predetermined size is a region within plus or minus 20 degrees before and after the peak value of the alternating current flowing in the rotating machine.

9. The rotating machine control device according to claim 1 or 2, characterized in that: The region larger than the predetermined size is a 70-degree region including a peak value of the AC current flowing through the rotating machine when the phase difference between the voltage command value and the current information is larger than 50 degrees.

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