Control device, drive device of motor, control method, and storage medium

Abstract

A control device for a permanent magnet synchronous motor, which has: a unit that sets voltage commands on two axes of a rotating orthogonal coordinate system; a unit that converts the voltage command coordinates of the two axes into three phases; a unit that applies the voltage commands of the three phases to the motor after power conversion by an inverter; a unit that feeds back terminal currents of the motor; a unit that determines a power factor angle from the fed back currents; and a unit that adds or subtracts the power factor angle from a phase used when converting the terminal currents of the motor obtained in the three phases into orthogonal coordinates, the control device is provided with: a holding section that holds a relationship of a variation of a direct current voltage supplied to the inverter and a correction value of a phase; and a unit that adds the correction value to at least one of a phase used when performing three-phase two-phase conversion that converts the three phases into two phases and a phase used when performing two-phase three-phase conversion that converts the two phases into three phases.

Description

Technical Field

[0001] This invention relates to a control device, a motor drive device, a control method, and a program.

[0002] This application claims priority to Japanese Patent Application No. 2021-023546, filed on February 17, 2021, the contents of which are incorporated herein by reference. Background Technology

[0003] Sometimes, the DC voltage generated by the converter is supplied to the inverter to control the inverter to drive the motor. Typically, the voltage output from the converter is smoothed by a large-capacity capacitor.

[0004] Previous technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent No. 4764124 Summary of the Invention

[0007] The technical problem to be solved by the invention

[0008] However, when the capacitance of the capacitor used to smooth the converter's output voltage is small, the device for driving the motor can be miniaturized. However, when the capacitor's capacitance is small, the converter's output voltage is more prone to fluctuation compared to when the capacitor's capacitance is large. As a result, in high-speed regions where the required motor voltage is above DC voltage, the motor voltage exhibits the effects of DC voltage fluctuations, leading to increased variations in motor speed or torque, potentially resulting in unstable motor operation. Furthermore, the variation in motor current also increases, potentially reducing the operating range.

[0009] Therefore, the following technology is needed: even when a varying voltage is input to the inverter, torque fluctuations, speed fluctuations, and reduction in the operating range of the motor in the high-speed region are suppressed.

[0010] The present invention was made to solve the above-mentioned problems, and its object is to provide a control device, a motor drive device, a control method and program that can suppress torque fluctuations, speed fluctuations and narrowing of the operating range in the high-speed region of a motor even when a fluctuating voltage is input to the inverter.

[0011] means for solving technical problems

[0012] To address the aforementioned issues, the control device of the present invention is a control device for a permanent magnet synchronous motor, comprising: a unit for setting voltage commands on two axes of a rotating orthogonal coordinate system; a unit for converting the voltage command coordinates of the two axes into three phases; a unit for applying the three-phase voltage commands to the motor after power conversion by an inverter; a unit for feeding back the terminal current of the motor; a power factor angle determination unit for determining the power factor angle based on the fed-back current; and a power factor angle addition / subtraction unit for adding or subtracting the power factor angle to the phase used when converting the terminal current of the motor obtained in the three phases into orthogonal coordinates. The control device further comprises: a holding unit for maintaining the relationship between variations in the DC voltage supplied to the inverter and a phase correction value; and a correction value addition unit for adding the correction value to at least one of the phase used when performing a three-phase to two-phase conversion and the phase used when performing a two-phase to three-phase conversion.

[0013] The motor drive device according to the present invention includes the above-mentioned control device and the inverter.

[0014] The control method involved in this invention is performed by a control device for a permanent magnet synchronous motor. The control device includes: a unit for setting voltage commands on two axes of a rotating orthogonal coordinate system; a unit for converting the voltage command coordinates of the two axes into three phases; a unit for applying the three-phase voltage commands to the motor after power conversion by an inverter; a unit for feeding back the terminal current of the motor; a power factor angle determination unit for determining the power factor angle based on the fed-back current; and a power factor angle addition / subtraction unit for adding or subtracting the power factor angle to the phase used when converting the terminal current of the motor obtained in the three phases into orthogonal coordinates. The control method includes the following steps: maintaining a relationship between the variation of the DC voltage supplied to the inverter and a phase correction value; and adding the correction value to at least one of the phase used when performing a three-phase to two-phase conversion and the phase used when performing a two-phase to three-phase conversion.

[0015] The program involved in this invention causes the computer of a control device for a permanent magnet synchronous motor to perform the following steps: maintaining a relationship between variations in the DC voltage supplied to the inverter and a phase correction value; and adding the correction value to at least one of the phase used in performing a three-phase to two-phase conversion and the phase used in performing a two-phase to three-phase conversion. The control device includes: a unit for setting voltage commands on two axes of a rotating orthogonal coordinate system; a unit for converting the voltage command coordinates of the two axes into three phases; a unit for applying the three-phase voltage commands to the motor after power conversion by the inverter; a unit for feeding back the terminal current of the motor; a power factor angle determination unit for determining the power factor angle based on the fed-back current; and a power factor angle addition / subtraction unit for adding or subtracting the power factor angle to the phase used when converting the terminal current of the motor obtained in the three phases into orthogonal coordinates.

[0016] Invention Effects

[0017] According to the control device, motor drive device, control method and program of the present invention, even when a varying voltage is input to the inverter, torque variation, speed variation or reduction of operating range in the high-speed region of the motor can be suppressed. Attached Figure Description

[0018] Figure 1 This is a diagram illustrating an example of the structure of a motor drive device based on an embodiment of the present invention.

[0019] Figure 2 This is a diagram illustrating an example of the structure of a control device based on an embodiment of the present invention.

[0020] Figure 3 This is a diagram illustrating an example of a first phase correction function based on an embodiment of the present invention.

[0021] Figure 4 This is a diagram illustrating an example of a second phase correction function based on an embodiment of the present invention.

[0022] Figure 5 Figure 1 is an example of the processing flow of a control device based on an embodiment of the present invention.

[0023] Figure 6 Figure 2 is an example of the processing flow of a control device based on an embodiment of the present invention.

[0024] Figure 7 It is a schematic block diagram showing the structure of a computer according to at least one embodiment. Detailed Implementation

[0025] <Implementation Method>

[0026] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings.

[0027] A motor drive device based on an embodiment of the present invention will be described.

[0028] (Structure of the motor drive unit)

[0029] Figure 1 This is a diagram showing the structure of a motor drive device 1 according to an embodiment of the present invention. Figure 1 As shown, the motor drive device 1 includes a power supply 10, a converter 20, a reactor 30, a first capacitor 40, a second capacitor 50, an inverter 60, a motor 70, a current sensor 80, and a control device 90.

[0030] The motor drive device 1 is such that, even in the case of large voltage fluctuations in the output voltage of the converter 20 in the high-speed region of the motor 70, the torque or speed pulsation of the motor 70 can be suppressed by controlling the inverter 60 according to the voltage fluctuations, and the reduction of the operating range can also be suppressed by suppressing the pulsation of the motor current.

[0031] Power supply 10 is a power source that outputs three-phase AC voltage. The three-phase AC voltage output from power supply 10 is input to converter 20.

[0032] Converter 20 converts three-phase AC voltage into DC voltage. Converter 20 is, for example, a diode rectifier circuit. However, converter 20 is not limited to a diode rectifier circuit and may also be other rectifier circuits using switching elements, etc.

[0033] Reactor 30 and first capacitor 40 constitute an LC filter. This LC filter eliminates voltage fluctuations in the output voltage of converter 20 caused by the resonant frequency component determined by the inductance of reactor 30 and the capacitance of first capacitor 40. First capacitor 40 is, for example, a film capacitor. Compared to electrolytic capacitors, film capacitors are typically smaller in capacitance, but smaller, lighter, and have a longer lifespan. When first capacitor 40 is a small-capacity film capacitor, the voltage fluctuation at the input of inverter 60 is larger compared to when first capacitor 40 is a large-capacity electrolytic capacitor.

[0034] The second capacitor 50 is a buffer capacitor. The buffer capacitor suppresses voltage fluctuations caused by switching noise generated when the inverter 60 uses switching elements to convert DC voltage to AC voltage.

[0035] Inverter 60 generates AC voltage for driving motor 70 from DC voltage supplied by converter 20 via the aforementioned LC filter, under the control of control device 90.

[0036] Inverter 60 includes switching elements SW1, SW2, SW3, SW4, SW5, and SW6. Switching elements SW1 to SW6 are, for example, semiconductor devices with control terminals (gate terminals in the case of IGBTs and MOSFETs), such as IGBTs (Insulated Gate Bipolar Transistors) and MOSFETs (Metal-Oxide-Semiconductor Field Effect Transistors).

[0037] The motor 70 rotates according to the AC voltage supplied to the inverter 60. The motor 70 is, for example, a compressor motor used in an air conditioner.

[0038] Current sensor 80 detects motor currents iu, iv, and iw. iu is the motor current corresponding to u in inverter 60. iv is the motor current corresponding to v in inverter 60. iw is the motor current corresponding to w in inverter 60.

[0039] (Structure of the control device)

[0040] Control device 90 generates control signals to control inverter 60. For example... Figure 2 As shown, the control device 90 includes a voltage detection circuit 110a, a current detection circuit 110b, a voltage command generation unit 110c, and a PWM (Pulse Width Modulation) duty cycle calculation unit 110d (an example of an calculation unit). Furthermore, as an example of a specific method for controlling a motor by the control device 90, V / F (Variable Frequency) control can be cited.

[0041] Voltage detection circuit 110a determines the voltage Vx between the two terminals of the first capacitor 40. For example, voltage detection circuit 110a includes an A / D (Analog to Digital) converter 110a1. A / D converter 110a1 receives the voltage Vx between the two terminals of the first capacitor 40. A / D converter 110a1 converts it into a digital value that corresponds one-to-one with the received voltage Vx (i.e., a digital value representing the value of the received voltage).

[0042] The current detection circuit 110b determines the values ​​of the motor currents iu, iv, and iw detected by the current sensor 80.

[0043] (Structure of the voltage command generation unit)

[0044] exist Figure 2 In this context, ω_cmd represents the speed command (electric angle). ω is the output frequency of inverter 60. vd is the d-axis voltage command. vq is the q-axis voltage command. vu is the voltage command for phase u. vv is the voltage command for phase v. vw is the voltage command for phase w. id is the inverter output current for the d-axis. iq is the inverter output current for the q-axis. Vx is the voltage between the two terminals of the first capacitor 40 detected by voltage detection circuit 110a. θc1 is the phase correction amount used when generating voltage commands vu, vv, and vw from the d-axis voltage command vd and the q-axis voltage command vq.

[0045] like Figure 2 As shown, the voltage command generation unit 110c includes a first functional unit f1, a second functional unit f2, a third functional unit f3, a fourth functional unit f4, a fifth functional unit f5, a sixth functional unit f6, a seventh functional unit f7, an eighth functional unit f8, a ninth functional unit f9, and a tenth functional unit f10.

[0046] Functional unit f1 receives the inverter output current iq from functional unit f10. Functional unit f1 multiplies the inverter output current iq by the proportional constant k. ω The inverter output current iq is the current that contributes to the torque generated by the motor 70. (As described in Patent Document 1, the proportionality constant k) ω The product of the inverter output current iq and k ω • Iq is used to feed back torque variations to speed to prevent loss of synchronization.

[0047] Functional unit f2 receives the output of functional unit f1. It also receives the speed command ω_cmd. Functional unit f2 subtracts the output of functional unit f1 from the speed command ω_cmd. Functional unit f2 outputs the result of this subtraction as the output frequency ω of inverter 60 to functional units f3, f4, and f8.

[0048] Functional unit f3 receives the output frequency ω of inverter 60 from functional unit f2. Furthermore, functional unit f3 receives the inverter output current id from functional unit f10. Functional unit f3 generates the d-axis voltage command vd by substituting the inverter output current id into equation (1) as shown below. Functional unit f3 outputs the generated d-axis voltage command vd to functional unit f5.

[0049] [Formula 1]

[0050]

[0051] Where Kpd is a proportionality constant.

[0052] Furthermore, the third functional unit f3 generates the q-axis voltage command vq by substituting the output frequency ω of the inverter 60 into equation (2) as shown below. The third functional unit f3 outputs the generated q-axis voltage command vq to the fifth functional unit f5.

[0053] [Formula 2]

[0054]

[0055] Where λd is the induced voltage coefficient. And Vqofs is the q-axis voltage offset value. In addition, the q-axis voltage offset value Vqofs can be expressed using the proportionality constant K as shown in equation (3) below.

[0056] [Formula 3]

[0057]

[0058] Furthermore, the inverter output current id is controlled to be zero by using the above equations (1) and (2). If the inverter output current id on the d-axis becomes zero, then the inverter output voltage on the d-axis also becomes zero.

[0059] Functional unit f4 receives the output frequency ω of inverter 60 from functional unit f2. Functional unit f4 integrates the output frequency ω of inverter 60 in the time axis direction. Functional unit f4 outputs the integration result to functional unit f6 and functional unit f7.

[0060] Functional unit f8 receives a digital value representing the voltage Vx between the two terminals of the first capacitor 40 from the voltage detection circuit 110a. Functional unit f8 also receives the output frequency ω of the inverter 60 from functional unit f2. Functional unit f8 determines a correction value θc1 based on the received digital value, the received output frequency ω, and the first phase correction function Fn1 (an example of the relationship between the variation of the DC voltage supplied to the inverter and the phase correction value). Functional unit f8 also determines a correction value θc2 based on the received digital value, the received output frequency ω, and the second phase correction function Fn2 (an example of the relationship between the variation of the DC voltage supplied to the inverter and the phase correction value). Correction value θc1 is used to correct the phase used during two-phase to three-phase conversion in functional unit f5. Correction value θc2 is used to correct the phase used during three-phase to two-phase conversion in functional unit f10. These correction values ​​θc1 and θc2 are values ​​used to control the phase magnitude based on the variation of the voltage Vx between the two terminals of the first capacitor 40. Figure 3This is a diagram illustrating an example of the first phase correction function Fn1 based on one implementation method. Figure 4 This diagram illustrates an example of the second phase correction function Fn2 based on one embodiment. The first phase correction function Fn1 is a function determined through prior simulation or experimentation, and it is a function that can determine the correction value θc1 using the DC voltage between the two terminals of the first capacitor 40 and the voltage required by the drive motor 70. Similarly, the second phase correction function Fn2 is a function determined through prior simulation or experimentation, and it is a function that can determine the correction value θc2 using the DC voltage between the two terminals of the first capacitor 40 and the voltage required by the drive motor 70. The correction value θc1 is applied to the phase in the seventh functional unit f7 where the two-phase to three-phase conversion occurs. Furthermore, the correction value θc2 is applied to the phase in the sixth functional unit f6 where the three-phase to two-phase conversion occurs.

[0061] Specifically, the first phase correction function Fn1 is a function of the voltage Vx between the two terminals of the first capacitor and the voltage required by the motor 70, and is also a function for determining the correction value. The voltage required by the motor 70 is obtained by multiplying the output frequency ω of the inverter 60 by the induced voltage coefficient λd. That is, the first phase correction function Fn1 is a function of the voltage Vx between the two terminals of the first capacitor and the output frequency ω of the inverter 60, and includes the induced voltage coefficient λd. Furthermore, each correction value θc1 is determined by substituting the voltage Vx between the two terminals of the first capacitor and the output frequency ω of the inverter 60 into the first phase correction function Fn1. That is, the eighth functional unit f8 substitutes the voltage Vx and the output frequency ω into the first phase correction function Fn1 to determine the value of the first phase correction function Fn1 (i.e., the correction value θc1). Thus, the correction value θc1 determined by the eighth functional unit f8 becomes the correction value used in the seventh functional unit f7.

[0062] Specifically, the second phase correction function Fn2 is a function of the voltage Vx between the two terminals of the first capacitor and the voltage required by the motor 70, and is also a function for determining the correction value. The voltage required by the motor 70 is obtained by multiplying the output frequency ω of the inverter 60 by the induced voltage coefficient λd. That is, the second phase correction function Fn2 is a function of the voltage Vx between the two terminals of the first capacitor and the output frequency ω of the inverter 60, and includes the induced voltage coefficient λd. Furthermore, each correction value θc2 is determined by substituting the voltage Vx between the two terminals of the first capacitor and the output frequency ω of the inverter 60 into the second phase correction function Fn2. That is, the eighth functional unit f8 substitutes the voltage Vx and the output frequency ω into the second phase correction function Fn2 to determine the value of the second phase correction function Fn2 (i.e., the correction value θc2). Thus, the correction value θc2 determined by the eighth functional unit f8 becomes the correction value used in the sixth functional unit f6.

[0063] Furthermore, when calculating the voltage required for the motor 70 in more detail, the 8th functional unit f8 can, for example, simply add the value obtained by multiplying the imaginary number j, the output frequency ω, the inductance of the q-axis, and the current of the q-axis to the value obtained by multiplying the output frequency ω by the induced voltage coefficient λd. That is, the 8th functional unit f8 can calculate the voltage required for the motor 70 simply by performing vector operations expressed in complex numbers (for example, by using the phasor method). At this time, the 8th functional unit f8 only needs to pre-store the inductance of the q-axis and use the inverter output current iq output by the 10th functional unit f10 as the current of the q-axis. As a result, the first phase correction function Fn1 and the second phase correction function Fn2 can be the same function or different functions.

[0064] Furthermore, the determination of correction values ​​θc1 and θc2 is not limited to using the aforementioned first phase correction function Fn1 or second phase correction function Fn2. For example, the voltage Vx between the two terminals of the first capacitor and the voltage required by the motor 70 are associated with their corresponding correction values ​​and stored, for example, as a data table (an example of the relationship between the variation of the DC voltage supplied to the inverter and the phase correction value). The eighth function unit f8 can also determine the voltage Vx between the two terminals of the first capacitor and the voltage required by the motor 70. In the data table, the correction value stored in association with the determined voltage Vx between the two terminals of the first capacitor and the voltage required by the motor 70 is determined as the desired correction value.

[0065] Functional unit f6 receives the integration result from functional unit f4. Furthermore, functional unit f6 receives the correction value θc2 from functional unit f8. Functional unit f6 adds the correction value θc2 to the integration result. That is, functional unit f6 uses the correction value θc2 to correct the integration result of the output frequency ω of inverter 60. Functional unit f6 outputs the summation result θes to functional unit f10.

[0066] Functional unit f10 receives the summation result θes from functional unit f6. Furthermore, functional unit f10 receives the respective motor currents iu, iv, and iw of phase u, phase v, and phase w from current detection circuit 110b at predetermined time intervals. Functional unit f10 uses the summation result θes as a phase and, for example, uses the following formula (4) to convert the three-phase motor currents iu, iv, and iw into inverter output currents id and iq. Functional unit f10 outputs the inverter output current id to functional unit f3. Furthermore, functional unit f10 outputs the inverter output current iq to functional unit f1 and functional unit f9.

[0067] [Formula 4]

[0068]

[0069] Functional unit f9 uses the inverter output current iq to determine the power factor angle φv. This determination can be performed, for example, in the same manner as described in Patent Document 1. Functional unit f9 outputs the determined power factor angle φv to functional unit f7.

[0070] Functional unit f7 receives the integration result from functional unit f4. It also receives the correction value θc1 from functional unit f8. Furthermore, it receives the power factor angle φv from functional unit f9. Functional unit f7 adds the integration result, the correction value θc1, and the power factor angle φv. It then outputs the summed result θv23 to functional unit f5.

[0071] Functional unit f5 receives the d-axis voltage command vd and the q-axis voltage command vq from functional unit f3. Furthermore, functional unit f5 receives the summation result θv23 from functional unit f7. Functional unit f5 converts the d-axis voltage command vd and the q-axis voltage command vq into the u-phase voltage command vu, the v-phase voltage command vv, and the w-phase voltage command vw, for example, using equation (5) as shown below.

[0072] [Formula 5]

[0073]

[0074] The PWM duty cycle calculation unit 110d generates a PWM signal with a determined duty cycle for controlling the inverter 60 based on the DC voltage between the two terminals of the first capacitor 40 and voltage commands vu, vv, and vw.

[0075] For example, in the high-speed region of the motor 70, the PWM duty cycle calculation unit 110d uses the phase θv23 corrected by the correction value θc1, and generates a PWM signal with a determined duty cycle for controlling the inverter 60 based on the voltage command vu of phase u, the voltage command vv of phase v and the voltage command vw of phase w output by the second-phase conversion of the third-phase function unit f5 and the DC voltage between the two terminals of the first capacitor 40.

[0076] (Processing performed by the control device)

[0077] Next, refer to Figure 5 and Figure 6The processing of two-phase to three-phase conversion and three-phase to two-phase conversion performed by the control device 90 when generating PWM signals for controlling the inverter 60 in the high-speed region of the motor 70 will be explained. First, the processing of two-phase to three-phase conversion performed by the control device 90 will be explained.

[0078] The voltage detection circuit 110a determines the voltage Vx between the two terminals of the first capacitor 40. The voltage detection circuit 110a outputs the determined voltage Vx to the eighth functional unit f8. The eighth functional unit f8 acquires the voltage Vx output by the voltage detection circuit 110a (step S1).

[0079] Furthermore, the second functional unit f2 outputs the output frequency ω of the inverter 60 to the eighth functional unit f8. The eighth functional unit f8 acquires the output frequency ω output by the second functional unit f2. The eighth functional unit f8 calculates the voltage required by the motor 70 based on the acquired output frequency ω (step S2). For example, the eighth functional unit f8 multiplies the output frequency ω by the induced voltage coefficient λd to calculate the voltage required by the motor 70.

[0080] The 8th function unit f8 determines the correction value θc1 from the 1st phase correction function Fn1. For example, the 8th function unit f8 substitutes the acquired voltage Vx and the calculated voltage required by the motor 70 into the 1st phase correction function Fn1 to determine the value of the 1st phase correction function Fn1, i.e., the correction value θc1 (step S3). The 8th function unit f8 outputs the determined correction value θc1 to the 7th function unit f7.

[0081] Functional unit f7 acquires the correction value θc1 output by functional unit f8. Furthermore, functional unit f7 acquires the integration result output by functional unit f4. Furthermore, functional unit f7 acquires the power factor angle φv output by functional unit f9. Functional unit f7 adds the integration result, power factor angle φv, and correction value θc1, and calculates the sum θv23. That is, functional unit f7 changes the phase used in the two-phase to three-phase conversion to θv23 by adding the correction value θc1 to the phase used in the two-phase to three-phase conversion (step S4). Functional unit f7 outputs phase θv23 to functional unit f5.

[0082] Functional unit f5 acquires the phase θv23 output by functional unit f7. Furthermore, functional unit f5 acquires the d-axis voltage command vd and the q-axis voltage command vq output by functional unit f3. Functional unit f5 uses phase θv23 to convert the two-axis voltage commands (i.e., d-axis voltage command vd and q-axis voltage command vq) into three-axis voltage commands (i.e., voltage command vu, voltage command vv, and voltage command vw) (step S5). Functional unit f5 outputs the three-axis voltage commands to the PWM duty cycle calculation unit 110d.

[0083] The PWM duty cycle calculation unit 110d acquires the three-axis voltage command output from the fifth function unit f5. Furthermore, the PWM duty cycle calculation unit 110d acquires the DC voltage Vx output from the voltage detection circuit 110a. Based on the three-axis voltage command output from the fifth function unit f5 and the DC voltage Vx output from the voltage detection circuit 110a, the PWM duty cycle calculation unit 110d generates a PWM signal to control the inverter 60. Finally, the PWM duty cycle calculation unit 110d outputs the generated PWM signal to the inverter 60.

[0084] Next, the three-phase to two-phase conversion process performed by the control device 90 will be explained.

[0085] Voltage detection circuit 110a determines the voltage Vx between the two terminals of the first capacitor 40. Voltage detection circuit 110a outputs the determined voltage Vx to the eighth function unit f8. The eighth function unit f8 acquires the voltage Vx output by voltage detection circuit 110a (step S6).

[0086] Furthermore, the second functional unit f2 outputs the output frequency ω of the inverter 60 to the eighth functional unit f8. The eighth functional unit f8 acquires the output frequency ω output by the second functional unit f2. The eighth functional unit f8 calculates the voltage required by the motor 70 based on the acquired output frequency ω (step S7). For example, the eighth functional unit f8 multiplies the output frequency ω by the induced voltage coefficient λd to calculate the voltage required by the motor 70.

[0087] The 8th function unit f8 determines the correction value θc2 from the 2nd phase correction function Fn2. For example, the 8th function unit f8 substitutes the acquired voltage Vx and the calculated voltage required by the motor 70 into the 2nd phase correction function Fn2 to determine the value of the 2nd phase correction function Fn2, i.e., the correction value θc2 (step S8). The 8th function unit f8 outputs the determined correction value θc2 to the 6th function unit f6.

[0088] Functional unit f6 acquires the correction value θc2 output by functional unit f8. Furthermore, functional unit f6 acquires the integration result output by functional unit f4. Functional unit f6 adds the integration result and the correction value θc2, and calculates the sum θes. That is, functional unit f6 changes the phase used in the three-phase-to-two-phase conversion to θes by adding the correction value θc2 to the phase (step S9). Functional unit f6 outputs the phase θes to functional unit f10.

[0089] Functional unit f10 of the 10th axis acquires the phase θes output by functional unit f6 of the 6th axis. Furthermore, functional unit f10 of the 10th axis acquires the motor current iu, motor current iv, and motor current iw output by the current detection circuit 110b. Functional unit f10 of the 10th axis uses the phase θes to convert the three-axis motor currents (i.e., motor current iu, motor current iv, and motor current iw) into two-axis motor currents (i.e., inverter output current id and inverter output current iq) (step S10). Functional unit f10 of the 10th axis outputs the two-axis motor currents to functional unit f1 of the 1st axis and functional unit f3 of the 3rd axis.

[0090] (Effects)

[0091] The above describes a motor drive device 1 based on the first embodiment of the present invention. In the motor drive device 1, the eighth functional unit f8 (an example of a holding unit) maintains the relationship between the voltage variation supplied to the inverter 60 and the phase correction value. The correction value addition units (f6, f7) add the correction value to at least one of the phase used when performing a three-phase to two-phase conversion and the phase used when performing a two-phase to three-phase conversion.

[0092] Therefore, in the motor drive unit 1, the control unit 90 can suppress torque fluctuations in the high-speed region of the motor, and also suppress speed fluctuations. Furthermore, when torque and speed fluctuations can be suppressed, compared to when torque and speed fluctuations cannot be suppressed, current pulsation can be suppressed and the peak current can be reduced. Thus, the control unit 90 can suppress torque and speed fluctuations, and also suppress the narrowing of the operating range.

[0093] In another embodiment of the present invention, the correction value θc1 and the correction value θc2 may be the same.

[0094] Furthermore, regarding the processing in the embodiments of the present invention, the order of processing can be changed within the scope of appropriate processing.

[0095] Each of the storage units or storage devices (including registers and latches) in the embodiments of the present invention can be located at any position within the range of appropriate information transmission and reception. Furthermore, for each of the storage units or storage devices, multiple units can exist and dispersedly store data within the range of appropriate information transmission and reception.

[0096] Embodiments of the present invention have been described, but the control device 90 and other control devices described above may have a computer system internally. Furthermore, the above-described processing procedure is stored in the form of a program on a computer-readable recording medium, and the above processing is performed by the computer reading and executing the program. Specific examples of computers are shown below.

[0097] Figure 7 It is a schematic block diagram showing the structure of a computer according to at least one embodiment.

[0098] like Figure 7 As shown, computer 5 has a CPU 6, main memory 7, storage device 8 and interface 9.

[0099] For example, the aforementioned control device 90 and other control devices are respectively installed in the computer 5. Furthermore, the operations of each of the aforementioned processing units are stored in the storage device 8 as programs. The CPU 6 reads the program from the storage device 8, expands it into the main memory 7, and executes the aforementioned processing according to the program. Furthermore, the CPU 6 secures the corresponding storage area in the main memory 7 according to the program.

[0100] Examples of storage devices 8 include HDDs (Hard Disk Drives), SSDs (Solid State Drives), magnetic disks, optical disks, CD-ROMs (Compact Disc Read Only Memory), DVD-ROMs (Digital Versatile Disc Read Only Memory), and semiconductor memories. Storage device 8 can be an internal medium directly connected to the bus of computer 5, or an external medium connected to computer 5 via interface 9 or a communication line. Furthermore, when the program is transmitted to computer 5 via the communication line, computer 5, upon receiving the transmission, can expand the program into main memory 7 and execute the aforementioned processing. In at least one embodiment, storage device 8 is a non-temporary tangible storage medium.

[0101] Furthermore, the aforementioned program can perform a portion of the functions described above. Moreover, the aforementioned program can be a file, a so-called differential file (differential program), capable of performing the aforementioned functions through combination with programs already recorded in the computer system.

[0102] Some embodiments of the present invention have been described, but these embodiments are examples and do not limit the scope of the invention. Various additions, omissions, substitutions and modifications can be made to these embodiments without departing from the spirit of the invention.

[0103] <Postscript>

[0104] The control device 90 described in the various embodiments of the present invention is as follows, for example.

[0105] (1) The control device (90) involved in the first method is a control device (90) for a motor (70), which has:

[0106] A unit (f3) that sets voltage commands on two axes of a rotating orthogonal coordinate system; a unit (f5) that converts the voltage command coordinates of the two axes into three phases.

[0107] The unit (110d) that applies the three-phase voltage command to the motor (70) after power conversion by the inverter (60).

[0108] Unit (110b) that provides feedback on the terminal current of the motor (70).

[0109] A power factor angle determination unit (f9) that determines the power factor angle based on the feedback current; and

[0110] A power factor angle addition / subtraction unit (f10) is used to add or subtract the power factor angle on the phase when converting the terminal current of the motor (70) obtained in the three phases into orthogonal coordinates.

[0111] The control device (90) includes:

[0112] The holding unit (f8) maintains the relationship between the variation of the DC voltage supplied to the inverter (60) and the phase correction value; and

[0113] The correction value addition unit (f6, f7) adds the correction value to at least one of the phase used when performing a three-phase to two-phase conversion and the phase used when performing a two-phase to three-phase conversion.

[0114] In this control device (90), the holding unit (f8) maintains the relationship between the variation of the DC voltage supplied to the inverter (60) and the phase correction value. The correction value addition unit (f6, f7) adds the correction value to at least one of the phase used when performing the three-phase to two-phase conversion and the phase used when performing the two-phase to three-phase conversion.

[0115] Therefore, the control device (90) can change the command using the relationship between the DC voltage variation and the phase correction value. As a result, even if a varying voltage is input to the inverter (60), torque variation, speed variation, or reduction in the operating range of the motor (70) in the high-speed region can be suppressed.

[0116] (2) The control device (90) involved in the second method is the control device (90) of (1), which has a detection unit (110a1) for detecting the change, and determines the correction value based on the detection result of the detection unit (110a1).

[0117] Therefore, the control device (90) can change the command based on the result detected by the detection unit (110a1). As a result, even when voltage fluctuations occur frequently, the voltage fluctuations can be detected at all times, so even when the fluctuating voltage is input to the inverter (60), torque fluctuations, speed fluctuations or reductions in the operating range of the motor (70) in the high-speed region can be suppressed at all times.

[0118] (3) The control device (90) involved in the third method is the control device (90) of (1) or (2), which has an arithmetic unit (110d) that generates control commands to control the inverter (60) based on the phase with the correction value added.

[0119] Thus, the control device (90) can expect to generate control commands for the inverter (60), which can suppress torque fluctuations, speed fluctuations, or reduced operating ranges in the high-speed region of the motor (70) even when a fluctuating voltage is input to the inverter (60).

[0120] (4) The control device (90) involved in the fourth method is the control device (90) of (3), wherein the arithmetic unit (110d) generates control commands to control the inverter (60) according to the change.

[0121] Thus, the control device (90) can expect to generate control commands for the inverter (60), which can suppress torque fluctuations, speed fluctuations, or reduced operating ranges in the high-speed region of the motor (70) even when a fluctuating voltage is input to the inverter (60).

[0122] (5) The control device (90) involved in the fifth method is the control device (90) of (4), wherein the arithmetic unit (110d) generates the control command according to the voltage required to drive the load (70) of the inverter (60).

[0123] Thus, the control device (90) can expect to generate control commands for the inverter (60), which can suppress torque fluctuations, speed fluctuations, or reduced operating ranges in the high-speed region of the motor (70) even when a fluctuating voltage is input to the inverter (60).

[0124] (6) The drive device for the motor (70) involved in the sixth method includes the above-mentioned control device and the inverter.

[0125] Therefore, the drive unit of the motor (70) can change the command by using the relationship between the change of DC voltage and the phase correction value. As a result, even if a changing voltage is input to the inverter (60), torque variation, speed variation or reduction of operating range in the high-speed region of the motor (70) can be suppressed.

[0126] (7) The drive device (1) of the motor (70) involved in the seventh method is the drive device (1) of the motor (70) of (6), which includes the control device (90) and the inverter (60).

[0127] Therefore, the drive unit (1) of the motor (70) can change the command by using the relationship between the change of DC voltage and the phase correction value. As a result, even if the changing voltage is input to the inverter (60), torque variation, speed variation or reduction of operating range in the high-speed region of the motor (70) can be suppressed.

[0128] (8) The control method involved in the eighth method is performed by a control device (90) of the motor (70), the control device (90) having: a unit (f3) for setting voltage commands on two axes of a rotating orthogonal coordinate system; a unit (f5) for converting the voltage command coordinates of the two axes into three phases; a unit (110d) for applying the three-phase voltage commands to the motor (70) after power conversion by an inverter (60); a unit (110b) for feeding back the terminal current of the motor (70); a power factor angle determination unit (f9) for determining the power factor angle based on the fed-back current; and a power factor angle addition / subtraction unit (f10) for adding or subtracting the power factor angle on the phase used when converting the terminal current of the motor (70) obtained in the three phases into orthogonal coordinates.

[0129] The control method includes the following steps:

[0130] The steps for maintaining the relationship between variations in the DC voltage supplied to the inverter (60) and the phase correction value; and

[0131] The step of adding the correction value to at least one of the phase used in performing the three-phase to two-phase conversion and the phase used in performing the two-phase to three-phase conversion.

[0132] Therefore, the control method can use the relationship between the DC voltage variation and the phase correction value to change the command. As a result, even if a varying voltage is input to the inverter (60), torque variation, speed variation, or reduction in the operating range of the motor (70) in the high-speed region can be suppressed.

[0133] (9) The program involved in the ninth method causes the computer (5) of the control device (90) of the motor (70) to perform the following steps: maintaining the relationship between the variation of the DC voltage supplied to the inverter (60) and the phase correction value; and adding the correction value to at least one of the phase used when performing the three-phase to two-phase conversion and the phase used when performing the two-phase to three-phase conversion, wherein the control device (90) has: a unit (f3) for setting voltage commands on two axes of a rotating orthogonal coordinate system; and The unit (f5) converts the voltage command coordinates of the two axes into three phases; the unit (110d) applies the three-phase voltage command to the motor (70) after power conversion by the inverter (60); the unit (110b) feeds back the terminal current of the motor (70); the power factor angle determination unit (f9) determines the power factor angle based on the fed-back current; and the power factor angle addition / subtraction unit (f10) adds or subtracts the power factor angle on the phase used when converting the terminal current of the motor (70) obtained in the three phases into orthogonal coordinates.

[0134] Therefore, the program can use the relationship between the DC voltage variation and the phase correction value to change the command. As a result, even if a varying voltage is input to the inverter (60), torque variation, speed variation, or reduced operating range in the high-speed region of the motor (70) can be suppressed.

[0135] Industrial availability

[0136] According to the control device, motor drive device, control method and program of the present invention, even when a varying voltage is input to the inverter, torque variation, speed variation or reduction of operating range in the high-speed region of the motor can be suppressed.

[0137] Symbol Explanation

[0138] 1-Motor drive unit, 5-Computer, 6-CPU, 7-Main memory, 8-Storage device, 9-Interface, 10-Power supply, 20-Converter, 30-Reactor, 40-First capacitor, 50-Second capacitor, 60-Inverter, 70-Motor, 80-Current sensor, 90-Control device, 110a-Voltage detection circuit, 110a1, 110b1-A / D converter, 110b-Current detection circuit, 110c-Voltage command generation unit, 110d-PWM duty cycle calculation unit, f1-First function unit, f2-Second function unit, f3-Third function unit, f4-Fourth function unit, f5-Fifth function unit, f6-Sixth function unit, f7-Seventh function unit, f8-Eighth function unit, f9-Ninth function unit, f10-Tenth function unit.

Claims

1. A control device for a permanent magnet synchronous motor, comprising: A unit that sets voltage commands on the two axes of a rotating orthogonal coordinate system; The voltage command coordinates of the two axes are converted into three-phase units; The unit that applies the three-phase voltage command to the motor after power conversion by the inverter; A unit that provides feedback on the terminal current of the motor; A power factor angle determination unit that determines the power factor angle based on the feedback terminal current; and A power factor angle addition / subtraction unit that adds or subtracts the power factor angle on the phase used when converting the terminal current of the motor obtained in the three phases into orthogonal coordinates. The control device includes: The holding section maintains the relationship between the periodic fluctuations of the DC voltage supplied to the inverter via a capacitor connected to the input of the inverter and a phase correction value; and The correction value addition unit adds the correction value to at least one of the phase used when converting the three phases into two phases corresponding to the two axes and the phase used when converting the two phases into three phases.

2. The control device according to claim 1, further comprising a detection unit that detects the change. The correction value is determined based on the detection results from the detection unit.

3. The control device according to claim 1 or 2, comprising an arithmetic unit that generates control commands for controlling the inverter based on the phase to which the correction value is added.

4. The control device according to claim 3, wherein, The arithmetic unit generates control commands for controlling the inverter based on the changes.

5. The control device according to claim 4, wherein, The arithmetic unit generates the control commands based on the voltage required to drive the load of the inverter.

6. A motor drive device comprising: The control device according to any one of claims 1 to 5; and The inverter.

7. The motor drive device according to claim 6, comprising a thin-film capacitor disposed at the input terminal of the inverter to suppress voltage fluctuations supplied to the inverter.

8. A control method performed by a control device for a permanent magnet synchronous motor, the control device comprising: a unit for setting voltage commands on two axes of a rotating orthogonal coordinate system; a unit for converting the voltage command coordinates of the two axes into three phases; a unit for applying the three-phase voltage commands to the motor after power conversion by an inverter; a unit for feeding back the terminal current of the motor; a power factor angle determination unit for determining a power factor angle based on the fed-back terminal current; and a power factor angle addition / subtraction unit for adding or subtracting the power factor angle on the phase used when converting the terminal current of the motor obtained in the three phases into orthogonal coordinates. The control method includes the following steps: The step of maintaining the relationship between the periodic variations of the DC voltage supplied to the inverter via a capacitor connected to the input of the inverter and a phase correction value; and The step of adding the correction value to at least one of the phase used in converting the three phases into two phases corresponding to the two axes and the phase used in converting the two phases into the three phases.

9. A storage medium storing a program that causes a computer of a control device for a permanent magnet synchronous motor to perform the following steps: maintaining a relationship between periodic variations of a DC voltage supplied to the inverter via a capacitor connected to the input of the inverter and a phase correction value; and adding the correction value to at least one of the phase used in performing a three-phase to two-phase conversion corresponding to two axes and the phase used in performing a two-phase to three-phase conversion, wherein the control device comprises: a unit for setting voltage commands on the two axes of a rotating orthogonal coordinate system; a unit for converting the voltage command coordinates of the two axes into three phases; a unit for applying the three-phase voltage commands to the motor after power conversion by the inverter; a unit for feeding back the terminal current of the motor; a power factor angle determination unit for determining a power factor angle based on the fed-back terminal current; and a power factor angle addition / subtraction unit for adding or subtracting the power factor angle to the phase used in converting the terminal current of the motor obtained in the three phases into orthogonal coordinates.

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