Motor control device and electric power steering device

Abstract

The motor control device of the present application includes a controller (6) that superimposes a ripple suppression voltage (Vq_FF) for reducing a pulsating component contained in torque generated by an alternating-current motor (1) on at least one of a first voltage command value (Vq1) corresponding to a command value of an output voltage of a first inverter (4a) and a second voltage command value (Vq2) corresponding to a command value of an output voltage of a second inverter (4b), wherein the ripple suppression voltage (Vq_FF) is calculated on the basis of a rotational position of the alternating-current motor having two winding groups by passing first drive currents (Iu1, Iv1, Iw1) output from the first inverter and second drive currents (Iu2, Iv2, Iw2) output from the second inverter into the two winding groups, respectively.

Description

Technical Field

[0001] This disclosure relates to a motor control device and an electric power steering device. Background Technology

[0002] As AC motors used for variable speed drives, synchronous motors that use permanent magnets in the rotor are used, namely permanent magnet synchronous motors (PMSM). In addition, in recent years, for the purpose of energy saving, synchronous motors that do not use permanent magnets in the rotor and only utilize reluctance torque have also begun to be used, namely synchronous reluctance motors (SynRM).

[0003] When controlling such a synchronous motor, reducing the torque ripple generated by the synchronous motor is an important concern. Patent document 1 below discloses a technique in which a q-axis vibration voltage command value with the same frequency as the torque ripple generated in the rotor's output torque, used to cancel the torque ripple component, is superimposed (added) to the q-axis basic voltage command value.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent No. 7090812 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] In recent years, the demand for reliability (fail-resistance) in motor control devices has been increasing. As a motor control device to meet this demand, motor control devices that drive a motor with two windings using two inverters have been put into use. In such motor control devices, it is naturally desirable to minimize torque ripple generated by the motor with two windings. However, the technology described in Patent Document 1 above has the problem of difficulty in suppressing torque ripple generated by a motor with two windings.

[0009] This disclosure was made in view of the above circumstances, and its object is to provide a motor control device and an electric power steering device that can improve reliability and quietness by suppressing torque pulsation generated by a motor having two winding sets.

[0010] Technical means for solving technical problems

[0011] To address the aforementioned issues, one aspect of this disclosure relates to a motor control device that controls a motor having two winding groups by channeling a first drive current output from a first inverter and a second drive current output from a second inverter into two winding groups respectively. The device includes a controller that superimposes a ripple suppression voltage, calculated based on the rotational position of the motor and reducing the ripple component in the torque generated by the motor, onto at least one of a first voltage command value corresponding to a command value of the output voltage of the first inverter and a second voltage command value corresponding to a command value of the output voltage of the second inverter.

[0012] Furthermore, one aspect of the electric power steering device disclosed herein includes: a torque detector that detects the steering torque of the steering gear; a motor having two winding groups respectively supplied with a first drive current output from a first inverter and a second drive current output from a second inverter, and generating a steering assist torque for the steering gear; and a motor control device that controls the drive of the motor based on the steering torque detected by the torque detector.

[0013] Invention Effects

[0014] According to this disclosure, torque pulsation generated by a motor having two winding sets can be suppressed, thereby simultaneously achieving improved reliability and quietness. Attached Figure Description

[0015] Figure 1 This is a block diagram showing the main structural components of the motor control device according to Embodiment 1 of this disclosure.

[0016] Figure 2 This is a schematic diagram illustrating an AC motor controlled by the motor control device according to Embodiment 1 of this disclosure.

[0017] Figure 3 This is a diagram illustrating the principle of generating on / off signals in Embodiment 1 of this disclosure.

[0018] Figure 4 This is a diagram illustrating the principle of generating on / off signals in Embodiment 1 of this disclosure.

[0019] Figure 5 This is a block diagram showing the internal structure of the offset calculation unit included in the motor control device according to Embodiment 1 of this disclosure.

[0020] Figure 6 This is a diagram showing the torque pulsation contained in the output torque of the AC motor in Embodiment 1 of this disclosure.

[0021] Figure 7 This indicates that in Embodiment 1 of this disclosure, when the current command value is made consistent with... Figure 6 A diagram showing the torque pulsation in the output torque of an AC motor under different conditions.

[0022] Figure 8 This is a graph showing the amplitude values ​​obtained from the combination of current command values ​​in Embodiment 1 of this disclosure.

[0023] Figure 9 This is a diagram showing the initial phase obtained from the combination of current command values ​​in Embodiment 1 of this disclosure.

[0024] Figure 10 This is a diagram showing the pulsation in the motor current in Embodiment 1 of this disclosure.

[0025] Figure 11 This indicates that in Embodiment 1 of this disclosure, when the current command value is made consistent with... Figure 10 A diagram showing the pulsation in the motor current under different conditions.

[0026] Figure 12 This is a graph showing the amplitude values ​​obtained from the combination of current command values ​​in Embodiment 1 of this disclosure.

[0027] Figure 13 This is a diagram showing the initial phase obtained from the combination of current command values ​​in Embodiment 1 of this disclosure.

[0028] Figure 14 This is a block diagram showing the main structural components of the motor control device according to Embodiment 2 of this disclosure.

[0029] Figure 15 This is a block diagram showing the internal structure of the first offset calculation unit of the motor control device according to Embodiment 2 of this disclosure.

[0030] Figure 16 This diagram illustrates the operation of the first pulsation suppression voltage distribution ratio setter included in the motor control device according to Embodiment 2 of this disclosure.

[0031] Figure 17 This diagram illustrates the operation of the first pulsation suppression current distribution ratio setter included in the motor control device according to Embodiment 2 of this disclosure.

[0032] Figure 18 This is a block diagram showing the internal structure of the second offset calculation unit of the motor control device according to Embodiment 2 of this disclosure.

[0033] Figure 19This is a diagram illustrating the operation of the second pulsation suppression voltage distribution ratio setter included in the motor control device according to Embodiment 2 of this disclosure.

[0034] Figure 20 This is a diagram illustrating the operation of the second pulsation suppression current distribution ratio setter included in the motor control device according to Embodiment 2 of this disclosure.

[0035] Figure 21 It is Figure 16 The characteristics shown are Figure 19 The diagram shows the composite properties.

[0036] Figure 22 This is a diagram illustrating the effect of the pulsation suppression voltage distribution ratio in Embodiment 2 of this disclosure.

[0037] Figure 23 This is a diagram illustrating the effect of the pulsation suppression voltage distribution ratio in Embodiment 2 of this disclosure.

[0038] Figure 24 This is a block diagram showing the main structural components of the motor control device according to Embodiment 3 of this disclosure.

[0039] Figure 25 This is a diagram illustrating the operation of the voltage limiting unit included in the motor control device according to Embodiment 3 of this disclosure.

[0040] Figure 26 This is a diagram illustrating the operation of the voltage limiting unit included in the motor control device according to Embodiment 3 of this disclosure.

[0041] Figure 27 This is a diagram illustrating the effect of the pulsation suppression voltage distribution ratio in Embodiment 3 of this disclosure.

[0042] Figure 28 This is a block diagram showing the main structural components of the motor control device according to Embodiment 4 of this disclosure.

[0043] Figure 29 This is a block diagram showing the internal structure of the first offset calculation unit of the motor control device according to Embodiment 4 of this disclosure.

[0044] Figure 30 This diagram illustrates the operation of the first pulsation suppression voltage distribution ratio setter included in the motor control device according to Embodiment 4 of this disclosure.

[0045] Figure 31 This diagram illustrates the operation of the first pulsation suppression current distribution ratio setter included in the motor control device according to Embodiment 4 of this disclosure.

[0046] Figure 32 This is a block diagram showing the internal structure of the second offset calculation unit included in the motor control device according to Embodiment 4 of this disclosure.

[0047] Figure 33 This diagram illustrates the operation of the second pulsation suppression voltage distribution ratio setter included in the motor control device according to Embodiment 4 of this disclosure.

[0048] Figure 34 This diagram illustrates the operation of the second pulsation suppression current distribution ratio setter included in the motor control device according to Embodiment 4 of this disclosure.

[0049] Figure 35 It is Figure 30 The characteristics shown are Figure 33 The diagram shows the composite properties.

[0050] Figure 36 This is a diagram illustrating the operation of the voltage limiting unit included in the motor control device according to Embodiment 4 of this disclosure.

[0051] Figure 37 This is a diagram showing the main structural components of the electric power steering device according to Embodiment 5 of this disclosure. Detailed Implementation

[0052] Hereinafter, the motor control device and electric power steering device according to the embodiments of this disclosure will be described in detail with reference to the accompanying drawings. Furthermore, in each embodiment, the same or corresponding parts are labeled with the same reference numerals, and repeated descriptions are omitted.

[0053] [Implementation Method 1]

[0054] Figure 1 This is a block diagram showing the main structural components of the motor control device according to Embodiment 1 of this disclosure. (As shown...) Figure 1 As shown, the motor control device involved in this embodiment includes a position detector 2, a first inverter 4a, a second inverter 4b, a current detector 5a, a current detector 5b, and a controller 6. This motor control device converts the DC power supplied from the DC power supply 3 into AC power to control the AC motor 1.

[0055] Figure 2 This is a schematic diagram illustrating an AC motor controlled by the motor control device according to Embodiment 1 of this disclosure. Figure 2As shown, the AC motor 1 has two sets of three-phase winding terminals and two three-phase winding groups. Specifically, the AC motor 1 has a first set of three-phase winding terminals U1, V1, W1 and a second set of three-phase winding terminals U2, V2, W2. Furthermore, the AC motor 1 has a first three-phase winding group (UV1, VW1, UW1) and a second three-phase winding group (UV2, VW2, UW2). The two three-phase winding groups are electrically insulated. Additionally, the two three-phase winding groups of the AC motor 1 can be as follows: Figure 2 The Δ connection is shown. Alternatively, it can also be a Y connection.

[0056] In the following description, AC motor 1 is explained as a permanent magnet synchronous motor that uses permanent magnets in the rotor. However, AC motor 1 can also be a wound-excited synchronous motor, a synchronous reluctance motor, a switched reluctance motor, or other synchronous motors.

[0057] Position detector 2 detects the rotational position θ of AC motor 1 and outputs the detection result to controller 6. DC power supply 3 has two outputs (high potential side and low potential side), outputting DC voltage (DC power supply voltage) Vdc as its terminal voltage to first inverter 4a and second inverter 4b. This DC power supply 3 can be any device that outputs DC voltage, such as a battery, DC-DC converter, diode rectifier, or PWM (Pulse Width Modulation) rectifier.

[0058] The first inverter 4a, based on the on / off signals Qup1 to Qwn1 from the controller 6, turns on and off the three semiconductor switching elements Sup1, Svp1, and Swp1 on the high-potential side and the three semiconductor switching elements Sun1, Svn1, and Swn1 on the low-potential side. Then, it converts the DC voltage Vdc input from the DC power supply 3 into AC voltage and applies AC voltage to the three-phase winding terminals U1, V1, and W1 of the AC motor 1, and flows currents Iu1, Iv1, and Iw1.

[0059] Here, the on / off signals Qup1, Qun1, Qvp1, Qvn1, Qwp1, and Qwn1 are respectively used to turn on and off the semiconductor switching elements Sup1, Sun1, Svp1, Svn1, Swp1, and Swn1 of the first inverter 4a. Hereinafter, it is assumed that if the value of the on / off signals Qup1 to Qwn1 is 1, a signal is output to turn on the corresponding semiconductor switching element. Furthermore, it is assumed that if the value of the on / off signals Qup1 to Qwn1 is 0, a signal is output to turn off the corresponding semiconductor switching element. In this embodiment, the semiconductor switching elements Sup1 to Swn1 are components formed by connecting semiconductor switches such as IGBTs (Insulated Gate Bipolar Transistors), bipolar transistors, and MOS (Metal-Oxide-Semiconductor) power transistors in reverse parallel with diodes.

[0060] The second inverter 4b, based on the on / off signals Qup2 to Qwn2 from the controller 6, turns on and off the three semiconductor switching elements Sup2, Svp2, and Swp2 on the high-potential side and the three semiconductor switching elements Sun2, Svn2, and Swn2 on the low-potential side. Then, it converts the DC voltage Vdc input from the DC power supply 3 into AC voltage and applies AC voltage to the three-phase winding terminals U2, V2, and W2 of the AC motor 1, and flows currents Iu2, Iv2, and Iw2.

[0061] Here, the on / off signals Qup2, Qun2, Qvp2, Qvn2, Qwp2, and Qwn2 are respectively used to turn on and off the semiconductor switching elements Sup2, Sun2, Svp2, Svn2, Swp2, and Swn2 of the second inverter 4b. Hereinafter, it is assumed that if the value of the on / off signals Qup2 to Qwn2 is 1, a signal is output to turn on the corresponding semiconductor switching element. Furthermore, it is assumed that if the value of the on / off signals Qup2 to Qwn2 is 0, a signal is output to turn off the corresponding semiconductor switching element. In this embodiment, the semiconductor switching elements Sup2 to Swn2 are components formed by connecting semiconductor switches such as IGBTs, bipolar transistors, and MOS power transistors in reverse parallel with diodes.

[0062] The current detector 5a detects the currents Iu1, Iv1, and Iw1 flowing through the three-phase winding terminals U1, V1, and W1 of the AC motor 1, and outputs each detected value as the current detection value Ius1, Ivs1, and Iws1. Hereinafter, the current flowing through the three-phase winding terminals U1, V1, and W1 is defined as the "first drive current".

[0063] As a current detector 5a, it can be used to detect the current by connecting a current detection resistor in series with the semiconductor switching elements Sun1, Svn1, and Swn1 of the first inverter 4a. Alternatively, it can be used to detect the DC current Iin1 by setting a current detection resistor between the first inverter 4a and the DC power supply 3, and to regenerate the currents Iu1, Iv1, and Iw1 flowing through the three-phase winding terminals U1, V1, and W1 of the AC motor 1.

[0064] Current detector 5b detects the currents Iu2, Iv2, and Iw2 flowing through the three-phase winding terminals U2, V2, and W2 of AC motor 1, and outputs each detected value as the current detection values ​​Ius2, Ivs2, and Iws2. Hereinafter, the currents flowing through the three-phase winding terminals U2, V2, and W2 are defined as the "second drive current".

[0065] As the current detector 5b, it can be detected by connecting a current detection resistor in series with the semiconductor switching elements Sun2, Svn2, and Swn2 of the second inverter 4b. Alternatively, it can be detected by placing a current detection resistor between the second inverter 4b and the DC power supply 3 to detect the DC current Iin2, and regenerate the currents Iu2, Iv2, and Iw2 flowing through the three-phase winding terminals U2, V2, and W2 of the AC motor 1.

[0066] The controller 6 inputs current command values ​​Id_target and Iq_target, which are command values ​​for the current supplied to the AC motor 1, and serves as the control target value for the AC motor 1. Furthermore, based on the rotational position θ detected by the position detector 2, the current detection values ​​Ius1, Ivs1, and Iws1 detected by the current detector 5a, and the current detection values ​​Ius2, Ivs2, and Iws2 detected by the current detector 5b, the controller 6 outputs on / off signals Qup1~Qwn1 and Qup2~Qwn2.

[0067] Controller 6 is implemented using a microcontroller, DSP, FPGA, or similar controller. Here, the control target value is set as the command value of the current supplied to AC motor 1, but it is not limited to this. For example, when controlling the speed of AC motor 1, the control target value is the speed command value of AC motor 1; when controlling the rotational position of AC motor 1, the control target value is the position command value of AC motor 1. Furthermore, in the cases of speed control and position control described above, the current command values ​​Id_target and Iq_target are generated internally by controller 6 as the operational variables for these controls. Additionally, when AC motor 1 is an auxiliary motor for electric power steering, the current command values ​​Id_target and Iq_target are generated internally by controller 6 based on the steering torque as the operational variables for these controls.

[0068] Next, controller 6 will be described in detail. Controller 6 includes coordinate converter 9a, subtractor 10a, subtractor 11a, current controller 12a, current controller 13a, adder 100a, coordinate converter 14a, and on / off signal generator 15a. Furthermore, controller 6 includes coordinate converter 9b, subtractor 10b, subtractor 11b, current controller 12b, current controller 13b, adder 100b, coordinate converter 14b, and on / off signal generator 15b. Additionally, controller 6 includes a speed calculation unit 16, a cancellation calculation unit 500, and gains 1000a, 1000b, 2000a, and 2000b.

[0069] The coordinate converter 9a calculates and outputs the currents Id1 and Iq1 on the two rotation axes based on the current detection values ​​Ius1, Ivs1, Iws1 and the rotation position θ. Furthermore, the currents Id1 and Iq1 on the two rotation axes are defined below as the "first detected current".

[0070] Subtractor 10a subtracts the current Id1 on the rotating two axes from the current command value Id_target and outputs the result to the current controller 12a. Subtractor 11a subtracts the current Iq1 on the rotating two axes from the value obtained by adding the first ripple suppression current Icancel_a (described later) to the current command value Iq_target and outputs the result to the current controller 13a.

[0071] The current controller 12a outputs a voltage command value Vd1 on the rotating two axes, corresponding to the output value of the subtractor 10a. This voltage command value Vd1 is used to make the output value of the subtractor 10a zero through proportional and integral control. Of course, the voltage command value Vd1 on the rotating two axes can also be calculated using known decoupling control.

[0072] The current controller 13a outputs a voltage command value Vq1 on the rotating two axes, corresponding to the output value of the subtractor 11a. This voltage command value Vq1 is used to make the output value of the subtractor 10a zero through proportional and integral control. Of course, the voltage command value Vq1 on the rotating two axes can also be calculated using known decoupling control.

[0073] Adder 100a adds the first ripple suppression voltage Vq_FF1 (described later) to the voltage command value Vq1 on the two rotating axes and outputs it as the voltage command value Vq1″ on the two rotating axes. Coordinate converter 14a calculates and outputs the voltage command values ​​Vu1, Vv1, and Vw1 based on the voltages Vd1 and Vq1″ on the two rotating axes and the rotation position θ. Here, the command values ​​of the voltages applied to the first inverter 4a, namely the voltage command values ​​Vu1, Vv1, and Vw1, and the voltage command values ​​Vd1 and Vq1 on the two rotating axes are defined as the "first voltage command value".

[0074] The on / off signal generator 15a outputs on / off signals Qup1 to Qwn1 based on voltage command values ​​Vu1, Vv1, and Vw1. Figure 3 This is a diagram illustrating the principle of generating on / off signals in Embodiment 1 of this disclosure. The on / off signal generator 15a compares the voltage command values ​​Vu1, Vv1, and Vw1 with a carrier wave (also called a carrier signal) C with a period Tc (frequency fc).

[0075] If the voltage command value Vu1 is greater than the carrier C, the on / off signal generator 15a sets the on / off signal Qup1 to on (1) and the on / off signal Qun1 to off (0). Conversely, if the voltage command value Vu1 is less than the carrier C, the on / off signal generator 15a sets the on / off signal Qup1 to off (0) and the on / off signal Qun1 to on (1).

[0076] Similarly, if the voltage command value Vv1 is greater than the carrier C, the on / off signal generator 15a sets the on / off signal Qvp1 to on (1) and the on / off signal Qvn1 to off (0). Conversely, if the voltage command value Vv1 is less than the carrier C, the on / off signal generator 15a sets the on / off signal Qvp1 to off (0) and the on / off signal Qvn1 to on (1).

[0077] Similarly, if the voltage command value Vw1 is greater than the carrier C, the on / off signal generator 15a sets the on / off signal Qwp1 to on (1) and the on / off signal Qwn1 to off (0). Conversely, if the voltage command value Vw1 is less than the carrier C, the on / off signal generator 15a sets the on / off signal Qwp1 to off (0) and the on / off signal Qwn1 to on (1).

[0078] Of course, a short-circuit protection time (dead time) can also be set to prevent the upper and lower switching elements of the first inverter 4a from being turned on simultaneously.

[0079] The above describes the calculations within controller 6 up to the point where the first voltage command value (voltage command value Vd1, Vq1, or voltage command value Vu1, Vv1, Vw1) is calculated based on the first detected current (current Id1, Iq1) and the current command value (Id_target, Iq_target) (or the calculations up to the point where the on / off signals Qup1 to Qwn1 are calculated). These calculations are equivalent to calculations performed by the first controller. In this embodiment, a first controller is present within controller 6.

[0080] The coordinate converter 9b calculates and outputs the currents Id2 and Iq2 on the two rotation axes based on the current detection values ​​Ius2, Ivs2, Iws2 and the rotation position θ. Hereinafter, the currents Id2 and Iq2 on the two rotation axes are defined as the "second detection current".

[0081] Subtractor 10b subtracts the current Id2 on the rotating second axis from the current command value Id_target and outputs the result to the current controller 12b. Subtractor 11b subtracts the current Iq2 on the rotating second axis from the value obtained by adding the second ripple suppression current Icancel_b (described later) to the current command value Iq_target and outputs the result to the current controller 13b.

[0082] The current controller 12b outputs a voltage command value Vd2 on the rotating two axes, corresponding to the output value of the subtractor 10b. This voltage command value Vd2 is a command value that makes the output of the subtractor 10b zero through proportional and integral control. Of course, the voltage command value Vd2 on the rotating two axes can also be calculated using known decoupling control.

[0083] The current controller 13b outputs a voltage command value Vq2 on the rotating two axes that corresponds to the output value of the subtractor 11b. This voltage command value Vq2 is a command value that makes the output of the subtractor 11b zero through proportional and integral control. Of course, the voltage command value Vq2 on the rotating two axes can also be calculated using known decoupling control.

[0084] Adder 100b adds the second ripple suppression voltage Vq_FF2 (described later) to the voltage command value Vq2 on the two rotating axes and outputs it as the voltage command value Vq2″ on the two rotating axes. Coordinate converter 14b calculates and outputs the voltage command values ​​Vu2, Vv2, and Vw2 based on the voltages Vd2 and Vq2″ on the two rotating axes and the rotation position θ. Here, the command values ​​of the voltages applied to the second inverter 4b, namely the voltage command values ​​Vu2, Vv2, and Vw2, and the voltage command values ​​Vd2 and Vq2 on the two rotating axes are defined as the "second voltage command values".

[0085] The on / off signal generator 15b outputs on / off signals Qup2 to Qwn2 based on voltage command values ​​Vu2, Vv2, and Vw2. Figure 4 This diagram illustrates the principle of generating on / off signals in Embodiment 1 of this disclosure. The on / off signal generator 15b compares the voltage command values ​​Vu2, Vv2, and Vw2 with a carrier wave (also called a carrier signal) C with a period Tc (frequency fc).

[0086] If the voltage command value Vu2 is greater than the carrier C, the on / off signal generator 15b sets the on / off signal Qup2 to on (1) and the on / off signal Qun2 to off (0). Conversely, if the voltage command value Vu2 is less than the carrier C, the on / off signal generator 15b sets the on / off signal Qup2 to off (0) and the on / off signal Qun2 to on (1).

[0087] Similarly, if the voltage command value Vv2 is greater than the carrier C, the on / off signal generator 15b sets the on / off signal Qvp2 to on (1) and the on / off signal Qvn2 to off (0). Conversely, if the voltage command value Vv2 is less than the carrier C, the on / off signal generator 15b sets the on / off signal Qvp2 to off (0) and the on / off signal Qvn2 to on (1).

[0088] Similarly, if the voltage command value Vw2 is greater than the carrier C, the on / off signal generator 15b sets the on / off signal Qwp2 to on (1) and the on / off signal Qwn2 to off (0). Conversely, if the voltage command value Vw2 is less than the carrier C, the on / off signal generator 15b sets the on / off signal Qwp2 to off (0) and the on / off signal Qwn2 to on (1).

[0089] Of course, in order to prevent the upper and lower switching elements of the second inverter 4b from being turned on at the same time, a short-circuit protection time (dead time) can also be set.

[0090] The above describes the calculations within controller 6 up to the point where the second voltage command values ​​(voltage command values ​​Vd2, Vq2, or voltage command values ​​Vu2, Vv2, Vw2) are calculated based on the second detected currents (currents Id2, Iq2) and the current command values ​​(Id_target, Iq_target). This calculation is equivalent to the calculations performed by the second controller. In this embodiment, a second controller is present within controller 6.

[0091] The speed calculation unit 16 outputs the rotational speed ω of the AC motor 1 by performing differential or difference operations on the rotational position θ. The output rotational speed of the AC motor 1 is the electrical angular velocity, which is the same as the mechanical angular velocity multiplied by the number of pole pairs of the AC motor 1.

[0092] The cancellation calculation unit 500 calculates and outputs the ripple suppression current Icancel2 to be applied to the current command value Iq_target in the subtractors 11a and 11b. In addition, the cancellation calculation unit 500 calculates and outputs the ripple suppression voltage Vq_FF to be allocated and applied to the first voltage command value Vq1 and the second voltage command value Vq2 in the adders 100a and 100b.

[0093] Gain 1000a multiplies the ripple suppression current Icancel2 output from the cancellation operation unit 500 by a factor of Ki, and outputs it as the first ripple suppression current Icancel_a to subtractor 11a. Here, Ki is a value that satisfies 0≦Ki≦1. Gain 1000b multiplies the ripple suppression current Icancel2 output from the cancellation operation unit 500 by a factor of (1-Ki), and outputs it as the second ripple suppression current Icancel_b to subtractor 11b.

[0094] Gain 2000a multiplies the ripple suppression voltage Vq_FF output from the cancellation operation unit 500 by a factor of Kv and outputs it as the first ripple suppression voltage Vq_FF1 to adder 100a. Here, Kv is a value that satisfies 0 ≤ Kv ≤ 1. Gain 2000b multiplies the ripple suppression voltage Vq_FF output from the cancellation operation unit 500 by a factor of (1-Ki) and outputs it as the second ripple suppression voltage Vq_FF2 to adder 100b.

[0095] Next, the cancellation calculation unit 500 installed in the controller 6 will be described in detail. Figure 5 This is a block diagram illustrating the internal structure of the cancellation calculation unit included in the motor control device according to Embodiment 1 of this disclosure. The cancellation calculation unit 500 includes a pulsation suppression current calculation unit 901 and a pulsation suppression voltage calculation unit 501. Based on the current command values ​​Id_target and Iq_target, the rotational position θ, and the rotational speed ω, it generates and outputs a pulsation suppression voltage vq_cancel and a pulsation suppression current i_cancel2. Furthermore, hereinafter, the pulsation suppression currents Icancel and Icancel2 will sometimes be referred to as pulsation suppression currents i_cancel and i_cancel2, respectively.

[0096] The pulsation suppression current calculation unit 901 includes a pulsation suppression current amplitude calculator 901a and a pulsation suppression current phase calculator 901b. Based on the current command values ​​Id_target and Iq_target and the rotation position θ, it calculates the pulsation suppression currents Icancel and Icancel2. The pulsation suppression current amplitude calculator 901a calculates and outputs the amplitude value i_ca_amp of the pulsation suppression currents Icancel and Icancel2 based on the current command values ​​Id_target and Iq_target. The pulsation suppression current phase calculator 901b calculates and outputs the initial phase i_ca_phase of the pulsation suppression current Icancel based on the current command values ​​Id_target and Iq_target. The steps of the pulsation suppression current amplitude calculator 901a calculating the amplitude value i_ca_amp of the pulsation suppression currents Icancel and Icancel2, and the steps of the pulsation suppression current phase calculator 901b calculating the initial phase i_ca_phase of the pulsation suppression current Icancel, will be described below.

[0097] Figure 6 This is a graph showing the torque pulsation contained in the output torque of the AC motor in Embodiment 1 of this disclosure. Specifically, Figure 6 This is a graph showing the torque pulsation in the output torque of the AC motor when the current command values ​​Id_target=Ida and Iq_target=Iqa (Ida and Iqa are constant values) and the rotational speed ω of AC motor 1 is constant.

[0098] Figure 6 The chart above shows the extracted value (T_6f) of the sixth-order electrical angle component contained in the output torque of AC motor 1. Figure 6 The graph in the middle section is a graph of the motor current obtained by multiplying the extracted value (T_6f) of the sixth electrical angle component contained in the output torque of AC motor 1 by "-Tdc / (2×Iq_target)". Here, Tdc is the DC value of the torque generated when the first drive current and the second drive current are applied to AC motor 1 under the current command values ​​Id_target=Ida and Iq_target=Iqa. Figure 6 The chart in the next section is... Figure 6 The chart in the middle section is a formulaic chart.

[0099] Here, from Figure 6From the peak value and assigned phase of the waveform in the middle or lower section of the graph, calculate the amplitude value "i_ca_amp(Ida, Iqa)" and the initial phase "i_ca_ph(Ida, Iqa)". Here, the parentheses in the amplitude value and initial phase indicate that these values ​​are given when the current command is Id_target=Ida and Iq_target=Iqa.

[0100] Figure 7 This indicates that in Embodiment 1 of this disclosure, when the current command value is made consistent with... Figure 6 A diagram showing the torque ripple in the output torque of an AC motor under different conditions. Specifically, Figure 7 This is a graph showing the torque pulsation in the output torque of the AC motor when the current command values ​​Id_target=Idb and Iq_target=Iqa (Idb and Iqa are constant values) and the rotational speed ω of AC motor 1 is kept constant.

[0101] in addition, Figure 7 The chart shown in the upper section and Figure 6 The chart above is also a chart showing the extracted value (T_6f) of the sixth electrical angular component contained in the output torque of AC motor 1. Figure 7 The chart shown in the middle section and Figure 6 Similarly, the middle section of the chart is a chart of the motor current obtained by multiplying the extracted value (T_6f) of the sixth electrical angle component contained in the output torque of AC motor 1 by "-Tdc / (2×Iq_target)". Figure 7 The chart in the next section is... Figure 7 The chart in the middle section is a formulaic chart.

[0102] Here, from Figure 6 Find the peak value of the waveform in the middle or lower section of the chart and assign it a phase, then calculate the amplitude value "i_ca_amp(Ida, Iqa)" and the initial phase "i_ca_ph(Ida, Iqa)".

[0103] The above describes Figure 6 The amplitude value "i_ca_amp(Ida, Iqa)" and the initial phase "i_ca_ph(Ida, Iqa)" shown are given in the case of "Id_target=Ida, Iq_target=Iqa". Figure 7The method for solving the amplitude value "i_ca_amp(Idb, Iqa)" and the initial phase "i_ca_ph(Idb, Iqa)" in the case of "Id_target=Idb, Iq_target=Iqa" is shown. Similarly, for the combination of current command values ​​(Id_target, Iq_target) that the AC motor 1 can be energized, the amplitude value "i_ca_amp(Id(i), Iq(j))" and the initial phase "i_ca_ph(Id(i), Iq(j))" are calculated in advance.

[0104] Figure 8 This is a graph showing the amplitude values ​​obtained from the combination of current command values ​​in Embodiment 1 of this disclosure. Figure 9 This is a diagram showing the initial phase obtained from the combination of current command values ​​in Embodiment 1 of this disclosure.

[0105] in addition, Figure 8 The amplitude values ​​"i_ca_amp(Id(i), Iq(j))" for each current command value (Id_target, Iq_target) shown can be stored, for example, in a table format in the pulsation suppression current amplitude arithmetic unit 901a. Additionally, Figure 9 The initial phase "i_ca_ph(Id(i), Iq(j))" for each current command value (Id_target, Iq_target) shown can be stored, for example, in the pulsation suppression current phase operator 901b in tabular form.

[0106] 901a reference to pulsation suppression current amplitude calculator Figure 8 The output shows the amplitude value i_ca_amp of the ripple suppression commands i_cancel and i_cance2 corresponding to the current command values ​​Id_target and Iq_target. Here, for example, if the current command value Iq_target is... Figure 7 The value between Iqa and Iqb in the equation can be obtained by the pulsation suppression current amplitude operator 901a, which can also output the amplitude value i_ca_amp through linear interpolation.

[0107] 901b reference to pulsation suppression current phase operator Figure 9 The content shown adds 90 degrees to the initial phase i_ca_ph corresponding to the current command values ​​Id_target and Iq_target, and outputs it as the initial phase i_ca_phase of the pulsation suppression current i_cancel. Here, adding 90 degrees is to advance the phase of the canceling voltage v_cancel (with N components and 1 period equal to 360 degrees) applied to allow the pulsation suppression current i_cancel2 to flow by 90 degrees.

[0108] When the amplitude value i_ca_amp is output from the pulsation suppression current amplitude calculator 901a and the initial phase i_ca_phase is output from the pulsation suppression current phase calculator 901b, the pulsation suppression current calculation unit 901 performs the calculations shown in equations (1-1) and (1-2) below, and outputs the pulsation suppression currents i_cancel and i_cancel2.

[0109] [Mathematical Expression 1]

[0110] [Mathematical Expression 2]

[0111] In equations (1-1) and (1-2) above, N is the desired number of times to be suppressed. For example, to suppress an electrical angle of order 6, N is set to 6. Furthermore, as... Figure 9 As shown, since there is a relationship of "i_ca_phase=i_ca_ph+90", according to the above equation (1-2), the following equation (1-3) holds.

[0112] [Mathematical Expression 3]

[0113] Therefore, the pulsation suppression currents i_cancel and i_cancel2 are related to... Figure 6 and Figure 7 The current command shown in the middle and lower sections of the graph is a sinusoidal motor current command that is equivalent to the current pulsation, is out of phase with the torque pulsation, and has an amplitude of 2 / (Tdc / Iq_target). Therefore, the following relationship holds for the amplitude value i_ca_amp, the current command value Iq_target, the DC value of the torque Tdc, and the extracted value T_6f of the sixth-order electrical angle component contained in the torque.

[0114] [Mathematical Expression 4]

[0115] The pulsation suppression current i_cancel2 is output from the cancellation operation unit 500 and input to the gain 1000a and gain 1000b. As mentioned above, the gain 1000a multiplies the pulsation suppression current I_cancel2 output from the cancellation operation unit 500 by Ki and outputs it as the first pulsation suppression current I_cancel_a to the subtractor 11a. Therefore, the relationship between the first pulsation suppression current I_cancel_a and the pulsation suppression current i_cancel2 is expressed by the following equation (1-5).

[0116] [Mathematical Expression 5]

[0117] Furthermore, as described above, the gain 1000b multiplies the pulsation suppression current Icancel2 output from the cancellation operation unit 500 by (1-Ki) and outputs it as the second pulsation suppression current Icancel_b to the subtractor 11b. Thus, the relationship between the second pulsation suppression current Icancel_b and the pulsation suppression current i_cancel2 is expressed by the following equation (1-6).

[0118] [Mathematical Expression 6]

[0119] Next, add equation (1-5) above to equation (1-6) above to obtain equation (1-7) below.

[0120] [Mathematical Expression 7]

[0121] From equation (1-7) above, it can be seen that the sum of the first ripple suppression current Icancel_a and the second ripple suppression current Icancel_b is equal to the ripple suppression current i_cancel2. Therefore, Ki can be considered as the distribution ratio of the ripple suppression current i_cancel2 to the first ripple suppression current Icancel_a. For example, when it is desired that the ripple suppression current i_cancel2 be equally distributed to the first drive current and the second drive current, Ki = 0.5 can be set. Furthermore, when it is desired that the distribution ratio of the first drive current is greater than that of the second drive current, Ki > 0.5 can be set. Conversely, when it is desired that the distribution ratio of the second drive current is greater than that of the first drive current, Ki < 0.5 can be set.

[0122] The pulsation suppression current i_cancel2 is allocated to the first pulsation suppression current Icancel_a and the second pulsation suppression current Icancel_b at a ratio of Ki:(1-Ki). The allocated first pulsation suppression current Icancel_a is input to the current controller 13a via subtractor 11a, and the allocated second pulsation suppression current Icancel_b is input to the current controller 13b via subtractor 11b.

[0123] Here, the set response frequency (cutoff frequency) of current controllers 13a and 13b is set to fq. If the frequency of the Nth electrical angle is below fq, the Nth electrical angle components of the q-axis currents Iq1 and Iq2 are consistent with the first ripple suppression current Icancel_a and the second ripple suppression current Icancel_b, respectively, which can suppress the torque ripple of the AC motor 1 at the Nth electrical angle. On the other hand, if the frequency of the Nth electrical angle exceeds fq, it exceeds the performance range of current controllers 13a and 13b. In such a frequency band, the ripple suppression voltage Vq_FF is the one in which the Nth electrical angle component of the control current Iq1+Iq2 is consistent with the ripple suppression current i_cancel2.

[0124] The pulsation suppression voltage calculation unit 501 includes an interference suppression instruction arithmetic unit 902, an adder 903, a multiplier 904, an adder 905, and a limiter 906. Based on the current instruction values ​​Id_target and Iq_target, the rotational position θ and rotational speed ω, and the pulsation suppression currents i_cancel and i_cancel2, the pulsation suppression voltage unit 501 calculates and outputs the pulsation suppression voltage vq_cancel.

[0125] The interference suppression command arithmetic unit 902 includes an interference suppression command amplitude arithmetic unit 902a and an interference suppression command phase arithmetic unit 902b. Based on the current command values ​​Id_target and Iq_target and the rotation position θ, it calculates the interference suppression command i_gairan. The interference suppression command amplitude arithmetic unit 902a calculates and outputs the amplitude value i_ga_amp of the interference suppression command i_gairan based on the current command values ​​Id_target and Iq_target. The interference suppression command phase arithmetic unit 902b calculates and outputs the initial phase i_ga_phase of the interference suppression command i_gairan based on the current command values ​​Id_target and Iq_target. The steps of the interference suppression command amplitude arithmetic unit 902a calculating the amplitude value i_ga_amp of the interference suppression command i_gairan, and the steps of the interference suppression command phase arithmetic unit 902b calculating the initial phase i_ga_phase of the interference suppression command i_gairan, are described below.

[0126] Figure 10 This is a graph showing the pulsations in the motor current in Embodiment 1 of this disclosure. Specifically, Figure 10 This is a diagram showing the pulsation in the motor current when the current command values ​​Id_target=Ida, Iq_target=Iqa (Ida and Iqa are constant values), the rotational speed ω of AC motor 1 is constant, and the first voltage command value (voltage command value Vd1, Vq1) and the second voltage command value (voltage command value Vd2, Vq2) are constant.

[0127] in addition, Figure 10 The graph in the upper section shows the extracted value (-i_gairan) of the sixth-order electrical angle component contained in the current Iq1+Iq2 of AC motor 1. This component is generated by the magnetic flux of the magnet of AC motor 1. The sixth component of the electrical angle of m and the sixth component of the inductance (the sixth component generated by the impedance distortion of AC motor 1) are generated. Figure 10 The chart in the next section is... Figure 10 The chart above is a reversed version of the previous chart.

[0128] Here, from Figure 10 The peak value and assigned phase of the waveform in the following graph are used to calculate the amplitude value "i_ga_amp(Ida, Iqa)" and the initial phase "i_ga_ph(Ida, Iqa)". Here, the parentheses in the amplitude value and initial phase indicate that these values ​​are given when the current command is Id_target=Ida and Iq_target=Iqa.

[0129] Figure 11 This indicates that in Embodiment 1 of this disclosure, when the current command value is made consistent with... Figure 10 A graph showing the pulsation in motor current under different conditions. Specifically, Figure 11 This is a diagram representing the pulsation in the motor current when the current command values ​​are set to Id_target=Idb and Iq_target=Iqa (Idb and Iqa are constant values), so that the rotational speed ω of AC motor 1 remains constant, and the first voltage command value (voltage command value Vd1, Vq1) and the second voltage command value (voltage command value Vd2, Vq2) remain constant.

[0130] in addition, Figure 11 The chart shown in the upper section and Figure 10 The chart above is also a chart showing the extracted values ​​(-i_gairan) of the sixth-order electrical angle component contained in the current Iq1+Iq2 of AC motor 1. Figure 11 The chart in the next section is... Figure 11 The chart above is a reversed version of the previous chart.

[0131] Here, from Figure 11 The peak value and phase assigned to the waveform in the chart below are used to calculate the amplitude value "i_ga_amp(Idb、Iqa)" and the initial phase "i_ga_ph(Idb、Iqa)".

[0132] The above describes Figure 10The amplitude value "i_ga_amp(Ida, Iqa)" and the initial phase "i_ga_ph(Ida, Iqa)" shown are given in the case of "Id_target=Ida, Iq_target=Iqa". Figure 11 The method for solving the amplitude value "i_ga_amp(Idb, Iqa)" and the initial phase "i_ga_ph(Idb, Iqa)" in the case of "Id_target=Idb, Iq_target=Iqa" is shown. Similarly, for the combination of current command values ​​(Id_target, Iq_target) that the AC motor 1 can be energized, the amplitude value "i_ga_amp(Id(i), Iq(j))" and the initial phase "i_ga_ph(Id(i), Iq(j))" are calculated in advance.

[0133] Figure 12 This is a graph showing the amplitude values ​​obtained from the combination of current command values ​​in Embodiment 1 of this disclosure. Figure 13 This is a diagram showing the initial phase obtained from the combination of current command values ​​in Embodiment 1 of this disclosure.

[0134] in addition, Figure 12 The amplitude values ​​"i_ga_amp(Id(i), Iq(j))" for each current command value (Id_target, Iq_target) shown can be stored, for example, in a table format in the interference suppression command amplitude arithmetic unit 902a. Additionally, Figure 13 The initial phase "i_ga_ph(Id(i), Iq(j))" for each current command value (Id_target, Iq_target) shown can be stored, for example, in the interference suppression command phase operator 902b in tabular form.

[0135] Interference suppression instruction amplitude arithmetic unit 902a reference Figure 12 The output shows the amplitude value i_ga_amp of the interference suppression command i_gairan corresponding to the current command values ​​Id_target and Iq_target. Here, for example, when the current command value Iq_target is... Figure 12 The value between Iqa and Iqb in the interference suppression instruction amplitude operator 902a can also output the amplitude value i_ga_amp through linear interpolation.

[0136] Interference suppression instruction phase operator 902b reference Figure 13The content shown adds 90 degrees to the initial phase i_ga_ph corresponding to the current command values ​​Id_target and Iq_target, and outputs it as the initial phase i_ga_phase of the interference suppression command i_gairan. Here, adding 90 degrees is to advance the phase of the cancellation voltage v_cancel (with N components and 1 period equal to 360 degrees) applied to enable the interference suppression command i_gairan by 90 degrees.

[0137] When the amplitude value i_ga_amp is output from the interference suppression instruction amplitude operator 902a and the initial phase i_ga_phase is output from the interference suppression instruction phase operator 902b, the interference suppression instruction operator 902 performs the operation shown in the following equation (1-8) and outputs the interference suppression instruction i_gaian.

[0138] [Mathematical Expression 8]

[0139] Adder 903, as shown in equation (1-9) below, outputs "i_sum" which is obtained by adding the pulsation suppression current i_cancel output from pulsation suppression current calculation unit 901 to the interference suppression instruction i_gairan output from interference suppression instruction calculation unit 902.

[0140] [Mathematical Expression 9]

[0141] The multiplier 904 is shown in equation (1-10) below. The output is the product of the output of the adder 903, i.e., "i_sum", and "rotational speed ω, inductance L of AC motor 1, and the number of times N is to be suppressed = N". ω The "v_sum" obtained by multiplying "L".

[0142] [Mathematical Expression 10]

[0143] In addition, when the mutual inductance M between the first three-phase winding group (UV1, VW1, UW1) and the second three-phase winding group (UV2, VW2, UW2) is not negligible relative to the inductance L of the AC motor 1, the multiplier 904 performs the operation shown in equation (1-10a) above.

[0144] Adder 905 is shown in equation (1-11) below. Its output is the product of the winding resistance R of AC motor 1 and the pulsation suppression current i_cancel2, "R", which is the output of multiplier 904, i.e., "v_sum". The result of "i_cancel2" is "v_sum2". Additionally, the wiring or conduction resistances of the first inverter 4a and the second inverter 4b can be added to the winding resistance R of the AC motor 1.

[0145] [Mathematical Expression 11]

[0146] In addition, when the mutual inductance M between the first three-phase winding group (UV1, VW1, UW1) and the second three-phase winding group (UV2, VW2, UW2) is not negligible relative to the inductance L of the AC motor 1, the adder 905 performs the operation shown in equation (1-11a) above.

[0147] In equation (1-11) or (1-11a) above, the first term on the right is proportional to the pulsation suppression current i_cancel2, and the second term on the right is proportional to the pulsation suppression current (i_cancel + i_gairan). Here, the pulsation suppression current i_cancel is 90 degrees ahead of the pulsation suppression current i_cancel2 in the Nth 360-degree electrical angle, so it can be said that the second term on the right is 90 degrees ahead of the pulsation suppression current i_cancel2 in phase. Furthermore, the coefficient "R" of the first term on the right and the coefficient "N" of the second term on the right... ω L or N ω The magnitude relationship of "(L+M)" varies depending on the rotation speed ω. That is, when the rotation speed ω is small, the first term on the right is greater than the second term on the right, and when the rotation speed ω is large, the first term on the right is less than the second term on the right. Therefore, "v_sum2" becomes a voltage that is 0 degrees more than or 90 degrees ahead of "i_cacnel2" in phase (pulsation suppression).

[0148] Limiter 906 limits the output of adder 905, “v_sum2”, to ±vq_clip and outputs it to adder 14 as the ripple suppression voltage vq_cancel. Specifically, the processing shown in (1-12) below is performed.

[0149] [Mathematical Expression 12]

[0150] Here, vq_clip is the maximum value of the electrical angle number N used as the suppression target, the maximum value of the rotational speed ω calculated by the cancellation calculation unit 500, the inductance L of the AC motor 1, and the maximum value of the sum of the interference suppression instruction i_gaian and the pulsation suppression instruction i_cancel, i_sum_max, which is represented by the following equation (1-13).

[0151] [Mathematical Expression 13]

[0152] Furthermore, when the mutual inductance M between the first three-phase winding group (UV1, VW1, UW1) and the second three-phase winding group (UV2, VW2, UW2) is not negligible relative to the inductance L of the AC motor 1, the value expressed by equation (1-13a) above is used. Alternatively, the rotational speed ω of the AC motor 1 can be input to the limiter 906, and the value of ωmax can be replaced with ω in equation (1-17).

[0153] Furthermore, when considering equation (1-11) above, equation (1-12) above becomes equation (1-14) below.

[0154] [Mathematical Expression 14]

[0155] As can be seen from the above equation (1-14), the limiter 906 multiplies the interference suppression command i_gairan and the pulsation suppression current i_cancel by a coefficient including the motor rotation speed ω, i.e., v_sum2, and limits it with a specified limit value vq_clip based on the motor rotation speed ω and inductance L. The limiter then superimposes the sum of the limited "interference suppression command and pulsation suppression current", i.e., the pulsation suppression voltage Vq_FF, onto the fundamental command Vq.

[0156] The pulsation suppression voltage Vq_FF is output from the cancellation operation unit 500 and input to gain 2000a and gain 2000b. As described above, gain 2000a multiplies the pulsation suppression voltage Vq_FF output from the cancellation operation unit 500 by a factor of Kv and outputs it as the first pulsation suppression voltage Vq_FF1 to adder 100a. Thus, the relationship between the first pulsation suppression voltage Vq_FF1 and the pulsation suppression voltage Vq_FF is expressed by the following equation (1-15).

[0157] [Mathematical Expression 15]

[0158] Furthermore, as described above, the gain 2000b multiplies the ripple suppression voltage Vq_FF output from the cancellation operation unit 500 by (1-Ki) times and outputs it as the second ripple suppression voltage Vq_FF2 to the adder 100b. Thus, the relationship between the second ripple suppression voltage Vq_FF2 and the ripple suppression voltage Vq_FF is expressed by the following equation (1-16).

[0159] [Mathematical Expression 16]

[0160] Next, add equation (1-15) above to equation (1-16) above to obtain equation (1-17) below.

[0161] [Mathematical Expression 17]

[0162] From equation (1-7) above, it can be seen that the sum of the first ripple suppression voltage Vq_FF1 and the second ripple suppression voltage Vq_FF2 is equal to the ripple suppression voltage Vq_FF. Therefore, the gain Kv can be considered as the distribution ratio of the ripple suppression voltage Vq_FF to the first ripple suppression voltage Vq_FF1. For example, when it is desired to distribute the ripple suppression voltage Vq_FF equally to the first ripple suppression voltage Vq_FF1 and the second ripple suppression voltage Vq_FF2, Kv = 0.5 can be set. Furthermore, when it is desired that the distribution ratio of the first ripple suppression voltage Vq_FF1 is greater than the distribution ratio of the second ripple suppression voltage Vq_FF2, Kv > 0.5 can be set. Conversely, when it is desired that the distribution ratio of the second ripple suppression voltage Vq_FF2 is greater than the distribution ratio of the first ripple suppression voltage Vq_FF1, Kv < 0.5 can be set.

[0163] Here, the settings for Ki and Kv are described. Ki can be considered the superposition (allocation ratio) of the first ripple suppression current Icancel_a on the current command value Iq_target of the first controller, and Kv can be considered the allocation ratio of the ripple suppression voltage Vq_FF to the first ripple suppression voltage Vq_FF1. In principle, Ki and Kv can be set independently. However, when Ki is set to a certain value, the current controller 13a controls the Nth harmonic component of Iq1 in the first detected current to be consistent with "ripple suppression current × Ki", and superimposes the value of "first ripple suppression voltage = ripple suppression voltage × Kv" onto its output.

[0164] Here, if Kv = Ki, then the value of "first ripple suppression voltage = ripple suppression voltage × Ki" is superimposed on the current controller 13a. Thus, the two functions of "superimposing the first ripple suppression current on the input value of the current controller 13a" and "superimposing the first ripple suppression voltage on the output value of the current controller 13a" work together on Iq1 in the first detected current, making its Nth harmonic component consistent with "ripple suppression current × Ki". Therefore, the effect of making the "Nth harmonic component of Iq1 in the first detected current consistent with "ripple suppression current × Ki" with higher precision is achieved.

[0165] By setting Ki = Kv, and simultaneously satisfying "1-Ki = 1-Kv", it means that the two functions of "superimposing the second pulsation suppression current on the input value of the current controller 13b" and "superimposing the second pulsation suppression voltage on the output value of the current controller 13b" work together on Iq2 in the second detection current, making its Nth harmonic component consistent with "pulsation suppression current × (1-Ki)". Thus, the effect of making the "Nth harmonic component of Iq2 in the second detection current consistent with "pulsation suppression current × (1-Ki)" with higher precision is achieved.

[0166] As described above, by making the allocation ratio of the pulsation suppression voltage superimposed on the first voltage command value and the second voltage command value consistent with the allocation ratio of the pulsation suppression current "the amount of superimposed on the current command value of AC motor 1 of the first controller" and "the amount of superimposed on the current command value of AC motor 1 of the second controller", the N-fold torque pulsation of AC motor 1 can be suppressed with higher precision.

[0167] Ki and Kv can both be set to 1, both to 0, or both to 0.5. When both Ki and Kv are set to 1, the entire ripple suppression current is superimposed on the first drive current. When both Ki and Kv are set to 0, the entire ripple suppression current is superimposed on the second drive current. When both Ki and Kv are set to 0.5, half of the ripple suppression current is equally distributed and superimposed on both the first and second drive currents. Of course, Ki and Kv can also be set to other values.

[0168] Next, the effects of Implementation Method 1 will be explained.

[0169] The q-axis voltage equation of AC motor 1 is expressed by the following equations (1-18) and (1-19).

[0170] [Mathematical Expression 18]

[0171] [Mathematical Expression 19]

[0172] Furthermore, in equations (1-18) and (1-19) above, R is the winding resistance, L is the inductance, and M is the mutual inductance between windings. It is the linkage flux. Furthermore, s is the Laplace operator.

[0173] Adding equations (1-18) and (1-19) together, we get equation (1-20).

[0174] [Mathematical Expression 20]

[0175] Here, let Vq1+Vq2=Vq_wa, Iq1+Iq2=Iq_wa, and let Id1=Id2=0, and ignore... Considering the pulsating component. At this time, when L+M contains the 6th electrical angle component (hereinafter referred to as LM_6f) in addition to the DC component (hereinafter referred to as LM_dc), the above equation (1-20) becomes the following equation (1-21).

[0176] [Mathematical Expression 21]

[0177] In equation (1-25) above, the condition of AC motor 1 rotating at high speed is considered. In this case, the first term on the right side is relatively small, so it is ignored. Furthermore, when AC motor 1 rotates at high speed, and the frequency of the corresponding sixth-order electrical angle component is higher than the response frequency of current controllers 13a and 13b, the sixth-order electrical angle component Vq_wa_6f contained in voltage Vq_wa is sufficiently small and can be regarded as 0. Considering the above factors, equation (1-21) above becomes equation (1-22) below. In equation (1-22) below, Iq_wa_dc and Iq_wa_6f are the DC component and the sixth-order electrical angle component contained in Iq_wa, respectively.

[0178] [Mathematical Expression 22]

[0179] If we solve equation (1-22) for Iq_wa_6f, we get equation (1-23).

[0180] [Mathematical Expression 23]

[0181] As shown in equation (1-23) above, the Iq_wa_6f component is generated by the presence of LM_6f. Here, if the response frequency of current controllers 13a and 13b is higher than the frequency of the sixth electrical angle component, feedback control is performed to make Iq_wa_6f zero, resulting in Iq_wa_6f approaching zero. That is, Vq_wa_6f is generated to reduce Iq_wa_6f. However, if the response frequency of current controllers 13a and 13b is lower than the frequency of the sixth electrical angle component, current controllers 13a and 13b cannot completely suppress Iq_wa_6f, and therefore Iq_wa_6f as shown in equation (1-23) above will be generated.

[0182] Therefore, when the impedance distortion of AC motor 1 exceeds the control frequency band of current controllers 13a and 13b, Iq_wa_6f as shown in equation (1-13) above will occur. In this specification, it is defined as the interference current caused by impedance distortion. The measurement results of the interference current are as follows: Figure 10 and Figure 11 As shown in the chart above.

[0183] In this embodiment, the interference suppression instruction arithmetic unit 902 firstly... Figure 10 and Figure 11 As shown in the middle section of the graph, calculate the amplitude and phase of the interference current reversal value, and as follows: Figure 12 and Figure 13 As shown, amplitude is directly mapped, while phase is mapped 90 degrees ahead. The resulting interference suppression command i_gairan, calculated in this way, is relative to... Figure 10 and Figure 11 The chart in the middle section becomes a command signal with the same amplitude and a phase advance of 90 degrees.

[0184] The interference suppression command i_gairan obtained by this calculation is ultimately multiplied by "N" in the pulsation suppression voltage Vq_FF ((Equation 1-14)). ω The result is reflected after L is multiplied. Additionally, in equation (1-14), when the proportion of mutual inductance between groups is not negligible relative to L, it is set as N. ω (L+M)” can be used. Therefore, the term Vq_FF_d in the pulsation suppression voltage Vq_FF caused by the interference suppression instruction i_gairan is as follows (1-24).

[0185] [Mathematical Expression 24]

[0186] On the other hand, the voltage Vgairan required to counteract the interference current represented by equation (1-23) is described. The impedance Z(N) of AC motor 1 relative to electrical angle N is given by equation (1-25) or (1-26). Furthermore, equation (1-25) is the formula when the effect of M is negligible, and equation (1-26) is the formula when the effect of M is not negligible.

[0187] [Mathematical Expression 25]

[0188] [Mathematical Expression 26]

[0189] In equations (1-25) and (1-26) above, j is a purely imaginary number (j×j=-1).

[0190] Furthermore, Vgairan is represented by the following equation (1-27) or (1-28). In addition, the following equation (1-27) is the formula when the influence of M is negligible, and the following equation (1-28) is the formula when the influence of M is not negligible.

[0191] [Mathematical Expression 27]

[0192] [Mathematical Expression 28]

[0193] In equations (1-27) and (1-28) above, “≒” means that in the region where the frequency of the sixth component of the electrical angle is much higher than the response frequency of the current controllers 13a and 13b, the influence of the winding resistance R of the AC motor 1 is much smaller than NωL and can be ignored.

[0194] Furthermore, as shown in equations (1-27) and (1-28) above, the voltage required to cancel the interference current Iq_wa_6f is obtained by advancing the phase of (-Iq_wa_6f) by 90 degrees after inverting the sign of the interference current Iq_wa_6f, and multiplying the amplitude by "NωL" or "Nω(L+M)". The reason for "advancing the phase by 90 degrees" is that the purely imaginary number j can be considered as a 90-degree phase shift operator.

[0195] Based on this, comparing equation (1-28) with equation (1-27) or (1-28), it can be seen that the interference suppression command i_gairan, as mentioned above, is a command to "invert the sign of the interference current Iq_wa_6f and advance its phase by 90 degrees." Therefore, it is consistent with the command in equation (1-27) or (1-28) where "j (-Iq_wa_6f)” is consistent. Therefore, equation (1-24) is equivalent to equation (1-27) or (1-28). Therefore, in this embodiment, by including the term containing the interference suppression instruction i_gaian obtained by the interference suppression instruction arithmetic unit 902 (equation (1-24)) in the pulsation suppression voltage Vq_FF shown in equation (1-14), the influence of interference current can be eliminated.

[0196] Next, the effects of the outputs of the pulsation suppression current calculation unit 901, namely the pulsation suppression currents i_cancel and i_cancel2, will be explained. In the torque equation of AC motor 1, let the torque constant be Kt, which is represented by the following equation (1-29).

[0197] [Mathematical Expression 29]

[0198] In this study, it is approximately assumed that the magnet torque of AC motor 1 is greater than the reluctance torque. If the motor has a larger proportion of reluctance torque, the currents Id1 and Id2 can also be included in the formula and considered in the same way.

[0199] In the above equation (1-29), when the torque constant Kt includes the electrical angle sixth-order component Kt_6f in addition to the DC component Kt_dc, it is represented by the following equation (1-30).

[0200] [Mathematical Expression 30]

[0201] In equation (1-30) above, when Iq_wa is kept constant, the first term on the right is the DC torque T_dc, and the second term on the right is the torque pulsation T_6f, which pulsates with electrical angle 6. If we assume that the DC component of Iq_wa is Iq_wa_dc, then when Iq_wa is constant, Iq_wa_dc = Iq_wa. Therefore, the second term T_6f on the right in equation (1-30) is the following equation (1-31).

[0202] [Mathematical Expression 31]

[0203] On the other hand, when Iq_wa is superimposed with a component Iq_wa_6f that pulsates with an electrical angle of 6 times, in addition to Iq_wa_dc, equation (1-30) becomes equation (1-32).

[0204] [Mathematical Expression 32]

[0205] In the above equation (1-32), “≒” is ignored because the product of the sixth-order electrical angular component Kt_6f of the torque constant and the sixth-order electrical angular component Iq_wa_6f of Iq_wa is small enough.

[0206] Here, we consider the case where the torque T is constant by superimposing the component Iq_wa_6f, which pulsates at the sixth electrical angle, to cancel out the second term T_6f on the right side of equation (1-32) (= equation (1-31)). In this case, it is only necessary to satisfy the condition that the second term on the right side + the third term on the right side = 0. Therefore, solving for Iq_wa_6f on this equation yields the following equation (1-33).

[0207] [Mathematical Expression 33]

[0208] As shown in equation (1-33) above, if the sixth-order electrical angle component of Iq_wa (hereinafter referred to as "torque cancellation current") can be set, then the sixth-order electrical angle component contained in T becomes 0.

[0209] In this embodiment, the pulsation suppression current calculation unit 901 firstly... Figure 6 and Figure 7As shown in the middle and lower sections of the chart, calculate the amplitude of the torque pulsation T_6f reversal value as a multiple of 1 / Kt and its phase, and as follows: Figure 8 and Figure 9 As shown, the amplitude is directly mapped, and the phase is mapped 90 degrees ahead. In addition, the above "1 / Kt times the amplitude of the torque pulsation T_6f reversal value" can be seen from equation (1-29) as equal to Tdc / (Iq1+Iq2).

[0210] The pulsation suppression current i_cancel obtained by this calculation is relative to Figure 6 and Figure 7 The graphs shown in the middle and lower sections represent command signals with the same amplitude but a phase advance of 90 degrees. Furthermore, the pulsation suppression current i_cancel2 output by the pulsation suppression current calculation unit 901 is a signal delayed by 90 degrees compared to i_cancel, therefore it is... Figure 6 and Figure 7 The charts shown in the middle and lower sections contain the same instruction signals.

[0211] The torque ripple suppression command i_cancel obtained by this calculation is ultimately multiplied by "N" in the cancellation voltage vq_cancel ((Equation 1-14)). ω The pulsation suppression command i_cancel2 is reflected in the pulsation suppression voltage Vq_FF by multiplying its amplitude by "R". Therefore, the term Vq_FF_T in the pulsation suppression voltage Vq_FF caused by the pulsation suppression currents i_cancel and i_cancel2 is expressed by the following equation (1-34). Where the influence of M is not negligible, L can be replaced with L+M.

[0212] [Mathematical Expression 34]

[0213] On the other hand, the voltage Vtorque required to supply the current Iq_wa_6f expressed by equation (1-33) is described. Since the impedance Z(N) of the AC motor 1 relative to the electrical angle N is given by equation (1-25) or (1-26), the voltage Vtorque is given by equation (1-35) or (1-36). Furthermore, equation (1-35) is the formula when the influence of M is negligible, and equation (1-36) is the formula when the influence of M is not negligible.

[0214] [Mathematical Expression 35]

[0215] [Mathematical Expression 36]

[0216] Here, for the current Iq_wa_6f, if the signal with constant amplitude and phase advance by 90 degrees is set as Iq_wa_6f_90, then equation (1-35) becomes equation (1-37) or equation (1-38). In addition, equation (1-37) is the formula when the influence of M is negligible, and equation (1-38) is the formula when the influence of M is not negligible.

[0217] [Mathematical Expression 37]

[0218] [Mathematical Expression 38]

[0219] Comparing equations (1-34) and (1-37) above, we can see that Iq_wa_6f equals i_cancel2, and Iq_wa_6f_90 equals i_cancel. Therefore, equations (1-34) and (1-37) are equivalent. Therefore, in this embodiment, by giving the pulsation suppression current application term in the cancellation voltage v_cancel (equation (1-14)) as in equation (1-34), it is possible to make the electrical angle 6th order component contained in the motor current consistent with the pulsation suppression current, which has the effect of reducing the torque pulsation component caused by the torque constant pulsation of AC motor 1.

[0220] Here, as Figure 1 As shown, in subtractors 11a and 11b, Icancel2 is distributed to the current command value Iq_target according to the allocation ratio and then added together. Therefore, in the region where the response frequency of current controllers 13a and 13b is higher than the frequency of the sixth electrical angle component, the current Iq1 + Iq2 is consistent with Iq_target + Icancel2 through the function of current controllers 13a and 13b. However, when the frequency of the sixth electrical angle component is higher than the response frequency of current controllers 13a and 13b, the function of current controllers 13a and 13b cannot make the current Iq1 + Iq2 consistent with Iq_target + Icancel2. Even under these circumstances, by adding a ripple suppression voltage Vq_FF, which takes into account the distribution ratio, to the first voltage command value Vq1 and the second voltage command value Vq2 in adders 100a and 100b, and making it include the terms of equation (1-34), the feedforward control takes effect, and as a result, the current Iq1+Iq2 is consistent with Iq_target+Icancel2, and the ripple component of the torque is reduced.

[0221] Furthermore, in the region where the frequency of the 6th component of the electrical angle is higher than the response frequency of current controllers 13a and 13b, and where the ripple suppression voltage Vq_FF is expected to be effective, if R If NωL holds true, then “R” is omitted from the pulsation suppression voltage Vq_FF ((1-34)). The effect of the "i_cancel2" option is not significantly different.

[0222] As described above, in this embodiment, the cancellation calculation unit 500 can generate a ripple suppression voltage Vq_FF. This ripple suppression voltage Vq_FF can suppress the interference current caused by the impedance distortion of the AC motor 1 while simultaneously introducing a ripple suppression current to compensate for the torque ripple caused by the torque constant ripple of the AC motor 1. Therefore, the torque ripple of the AC motor 1, especially in the high-speed rotation region, can be reduced.

[0223] Furthermore, when the operating range where noise and vibration of AC motor 1 become problematic is limited to situations where the frequency of the sixth electrical angle component is higher than the response frequency of current controllers 13a and 13b, it is not necessarily required to add a pulsation suppression current Icancel2 to subtractors 11a and 11b. Even without adding a pulsation suppression current Icancel2 to subtractors 11a and 11b, when the frequency of the sixth electrical angle component is higher than the response frequency of current controllers 13a and 13b, the torque pulsation, noise, and vibration of AC motor 1 can still be reduced through the action of the pulsation suppression voltage Vq_FF.

[0224] Furthermore, when one of the two inverters supplying power to AC motor 1, namely the first inverter 4a (and its controller, referred to as the "first system") and the second inverter 4b (and its controller, referred to as the "second system"), stops due to a fault, the ripple suppression current and voltage supplied to the other system can be stopped. This has the effect that when one system fails, priority is given to ensuring the torque generated by the supply current from the other system, rather than reducing torque ripple, noise, and vibration of AC motor 1.

[0225] [Implementation Method 2]

[0226] Figure 14 This is a block diagram showing the main structural components of the motor control device according to Embodiment 2 of this disclosure. Additionally, in Figure 14 In China, for the sake of Figure 1 Structures that are identical to those shown are labeled with the same reference numerals. Furthermore, in this embodiment, descriptions of structures identical to those described in Embodiment 1 are omitted.

[0227] The motor control device involved in this embodiment and Figure 1 Compared to the motor control device shown, the main difference is that two DC power supplies 3a and 3b are used instead. Figure 1 The DC power supply 3 is replaced by two controllers 6a and 6b. Figure 1The controller 6 shown.

[0228] DC power supplies 3a, 3b and Figure 1 The DC power supply 3 shown is identical. DC power supply 3a outputs the DC power supply voltage Vdc1 (first power supply voltage) to the first inverter 4a. DC power supply 3b outputs the DC power supply voltage Vdc2 (second power supply voltage) to the second inverter 4b. Furthermore, these DC power supplies 3a and 3b can be any device that outputs DC voltage, such as a battery, DC-DC converter, diode rectifier, or PWM rectifier.

[0229] The first inverter 4a and the second inverter 4b are the same as those described in Embodiment 1. However, the first inverter 4a in this embodiment differs in that it receives the DC power supply voltage Vdc1 (first power supply voltage) output from the DC power supply 3a and is driven by the on / off signals Qup1 to Qwn1 output from the controller 6a. Furthermore, the second inverter 4b in this embodiment differs in that it receives the DC power supply voltage Vdc2 (second power supply voltage) output from the DC power supply 3b and is driven by Qup2 to Qwn2 output from the controller 6b.

[0230] The first controller 6a and the second controller 6b can be said to be... Figure 1 The controller 6 shown is functionally divided into two. That is, in embodiment 1, controller 6 contains both a first controller and a second controller, but in this embodiment, the first controller 6a contains the first controller, and the second controller 6b contains the second controller. Furthermore, in embodiment 1, controller 6 is implemented by a microcontroller, DSP, FPGA, or other controller, but in this embodiment, controller 6a is implemented by one controller, and controller 6b is implemented by another controller.

[0231] The first controller 6a includes Figure 1 The controller 6 shown includes a coordinate converter 9a, a subtractor 10a, a subtractor 11a, a current controller 12a, a current controller 13a, an adder 100a, a coordinate converter 14a, and an on / off signal generator 15a. Furthermore, the first controller 6a includes a speed calculation unit 16a and a first cancellation calculation unit 500a.

[0232] The second controller 6b includes Figure 1 The controller 6 shown includes a coordinate converter 9b, a subtractor 10b, a subtractor 11b, a current controller 12b, a current controller 13b, an adder 100b, a coordinate converter 14b, and an on / off signal generator 15b. Furthermore, the second controller 6b includes a speed calculation unit 16b and a second cancellation calculation unit 500b.

[0233] Figure 15This is a block diagram showing the internal structure of the first cancellation calculation unit included in the motor control device according to Embodiment 2 of this disclosure. Furthermore, in Figure 15 In China, for the sake of Figure 5 Structures with the same structure shown are labeled with the same reference numerals. For example... Figure 15 As shown, the first cancellation calculation unit 500a, in addition to Figure 5 In addition to the pulsation suppression current calculation unit 901 and the pulsation suppression voltage calculation unit 501 shown, the system also includes a first pulsation suppression voltage allocation ratio setter 10000a and a first pulsation suppression current allocation ratio setter 20000a. This first cancellation calculation unit 500a generates and outputs a first pulsation suppression voltage Vq_FF1 and a first pulsation suppression current I_cancel_a based on the current command values ​​Id_target1 and Iq_target1, the rotation position θ, and the rotation speed ω.

[0234] The first ripple suppression voltage allocation ratio setter 10000a calculates Kv (the allocation ratio of ripple suppression voltage Vq_FF to first ripple suppression voltage Vq_FF1) based on the first power supply voltage Vdc1 and the second power supply voltage Vdc2, and outputs Kv×Vq_FF as the first ripple suppression voltage Vq_FF1. The first ripple suppression current allocation ratio setter 20000a calculates Ki (the allocation ratio of ripple suppression current i_cancel2 to first ripple suppression current I_cancel_a) based on the first power supply voltage Vdc1 and the second power supply voltage Vdc2, and outputs Ki×i_cancel2 as the first ripple suppression current I_cancel_a.

[0235] Figure 16 This diagram illustrates the operation of the first pulsation suppression voltage distribution ratio setter included in the motor control device according to Embodiment 2 of this disclosure. Additionally, Figure 16 In the chart shown, the horizontal axis represents the difference between the first power supply voltage Vdc1 and the second power supply voltage Vdc2, "Vdc1-Vdc2", and the vertical axis represents the first ripple suppression voltage Vq_FF1 (=Kv). Vq_FF).

[0236] like Figure 16As shown, the first ripple suppression voltage distribution ratio setter 10000a is set such that if "Vdc1-Vdc2" exceeds the positive threshold Vth, it outputs "Vq_FF1 = Vq_FF (Kv = 1)"; and if "Vdc1-Vdc2" is below the negative threshold -Vth, it outputs "Vq_FF1 = 0.0 (Kv = 0)". Furthermore, the first ripple suppression voltage distribution ratio setter 10000a is set such that if "Vdc1-Vdc2" is above the negative threshold -Vth and below the positive threshold Vth, Vq_FF1 continuously varies from 0 to Vq_FF. Specifically, if Vdc1 = Vdc2 (the first power supply voltage and the second power supply voltage are equal), it is set to output "Vq_FF1 = 0.5Vq_FF (Kv = 0.5)". Here, the threshold setting is, for example, set to Vq_FF × √2.

[0237] Figure 17 This diagram illustrates the operation of the first pulsation suppression voltage distribution ratio setter included in the motor control device according to Embodiment 2 of this disclosure. Additionally, Figure 17 In the chart shown, the horizontal axis represents the difference between the first power supply voltage Vdc1 and the second power supply voltage Vdc2, "Vdc1-Vdc2", and the vertical axis represents the first pulsation suppression current I_cancel_a (=Ki i_cancel2).

[0238] like Figure 17 As shown, the first ripple suppression current distribution ratio setter 20000a is set such that if "Vdc1-Vdc2" exceeds the positive threshold Vth, it outputs "I_cancel_a = i_cancel2 (Ki = 1)"; and if "Vdc1-Vdc2" is below the negative threshold -Vth, it outputs "I_cancel_a = 0.0 (Ki = 0)". Furthermore, the first ripple suppression current distribution ratio setter 20000a is set such that if "Vdc1-Vdc2" is above the negative threshold -Vth and below the positive threshold Vth, then I_cancel_a continuously varies from 0 to i_cancel2. Specifically, if Vdc1 = Vdc2 (the first power supply voltage and the second power supply voltage are equal), it is set to output "I_cancel_a = 0.5i_cancel2 (Ki = 0.5)".

[0239] Figure 18 This is a block diagram showing the internal structure of the second cancellation calculation unit included in the motor control device according to Embodiment 2 of this disclosure. Furthermore, in Figure 18 In China, for the sake of Figure 5 Structures with the same structure shown are labeled with the same reference numerals. For example... Figure 18 As shown, the second cancellation calculation unit 500b, in addition to Figure 5In addition to the pulsation suppression current calculation unit 901 and the pulsation suppression voltage calculation unit 501 shown, the system also includes a second pulsation suppression voltage allocation ratio setter 10000b and a second pulsation suppression current allocation ratio setter 20000b. This second cancellation calculation unit 500b generates and outputs a second pulsation suppression voltage Vq_FF2 and a second pulsation suppression current I_cancel_b based on the current command values ​​Id_target2, Iq_target2, the rotation position θ, and the rotation speed ω.

[0240] The second ripple suppression voltage allocation ratio setter 10000b calculates (1-Kv) (the allocation ratio of the ripple suppression voltage Vq_FF to the second ripple suppression voltage Vq_FF2) based on the first power supply voltage Vdc1 and the second power supply voltage Vdc2, and outputs (1-Kv)×Vq_FF as the second ripple suppression voltage Vq_FF2. The second ripple suppression current allocation ratio setter 20000b calculates (1-Ki) (the allocation ratio of the ripple suppression current i_cancel2 to the second ripple suppression current I_cancel_b) based on the first power supply voltage Vdc1 and the second power supply voltage Vdc2, and outputs (1-Ki)×i_cancel2 as the second ripple suppression current I_cancel_b.

[0241] Figure 19 This diagram illustrates the operation of the second pulsation suppression voltage distribution ratio setter included in the motor control device according to Embodiment 2 of this disclosure. Additionally, Figure 19 In the chart shown, the horizontal axis represents the difference between the first power supply voltage Vdc1 and the second power supply voltage Vdc2, "Vdc1-Vdc2", and the vertical axis represents the second ripple suppression voltage Vq_FF2 (= (1-Kv)). Vq_FF).

[0242] like Figure 19 As shown, the second ripple suppression voltage distribution ratio setter 10000b is set to output "Vq_FF2=0 (Kv=1)" if "Vdc1-Vdc2" exceeds the positive threshold Vth, and output "Vq_FF2=Vq_FF (Kv=0)" if "Vdc1-Vdc2" is below the negative threshold -Vth. Furthermore, the second ripple suppression voltage distribution ratio setter 10000b is set to continuously vary Vq_FF2 from Vq_FF to 0 if "Vdc1-Vdc2" is above the negative threshold -Vth and below the positive threshold Vth. Specifically, if Vdc1=Vdc2 (the first power supply voltage and the second power supply voltage are equal), it is set to output "Vq_FF2=0.5Vq_FF (Kv=0.5)".

[0243] Figure 20This diagram illustrates the operation of the first pulsation suppression voltage distribution ratio setter included in the motor control device according to Embodiment 2 of this disclosure. Additionally, Figure 20 In the chart shown, the horizontal axis represents the difference between the first power supply voltage Vdc1 and the second power supply voltage Vdc2, "Vdc1-Vdc2", and the vertical axis represents the second pulsation suppression current I_cancel_b (= (1-Ki)). i_cancel2).

[0244] like Figure 20 As shown, the second ripple suppression current distribution ratio setter 20000b is set to output "I_cancel_b = 0 (Ki = 1)" if "Vdc1 - Vdc2" exceeds the positive threshold Vth, and output "I_cancel_b = Icancel2 (Ki = 0)" if "Vdc1 - Vdc2" is below the negative threshold -Vth. Furthermore, the second ripple suppression current distribution ratio setter 20000b is set to continuously vary I_cancel_b from i_cancel2 to 0 if "Vdc1 - Vdc2" is above the negative threshold -Vth and below the positive threshold Vth. Specifically, if Vdc1 = Vdc2 (the first power supply voltage and the second power supply voltage are equal), it is set to output "I_cancel_b = 0.5i_cancel2 (Ki = 0.5)".

[0245] Figure 21 It is Figure 16 The characteristics shown are Figure 19 The diagram shows the synthesized characteristics. Specifically, Figure 21 It is Figure 16 The characteristics of the first ripple suppression voltage Vq_FF1 relative to "Vdc1-Vdc2" are shown below. Figure 19 The graph shown is a composite of the characteristics of the second ripple suppression voltage Vq_FF2 relative to "Vdc1-Vdc2". From... Figure 21 The following conclusions can be drawn.

[0246] Case 1: When “Vdc1-Vdc2>Vth”, Vq_FF1=Vq_FF, Vq_FF2=0.

[0247] Case 2: When “Vdc1-Vdc2<-Vth”, Vq_FF1=0, Vq_FF2=Vq_FF.

[0248] Case 3: Except for cases 1 and 2, Vq_FF1 and Vq_FF2 change continuously relative to "Vdc1-Vdc2". In particular, when "Vdc1=Vdc2", Vq_FF1=Vq_FF2.

[0249] Case 4: In all cases, Vq_FF1 + Vq_FF2 = Vq_FF holds true.

[0250] As can be seen from "Case 4" above, since the sum of the ripple suppression voltages supplied from the first inverter 4a and the second inverter 4b is equal to Vq_FF, the function of suppressing torque ripple of the AC motor 1 is maintained, similar to Embodiment 1. Furthermore, as can be seen from "Case 1" and "Case 3" above, when Vdc1 > Vdc2, Vq_FF1 > Vq_FF2, and the proportion of the first ripple voltage increases. Conversely, as can be seen from "Case 2" and "Case 3" above, when Vdc1 < Vdc2, Vq_FF1 < Vq_FF2, and the proportion of the second ripple voltage increases.

[0251] Figure 22 and Figure 23 This is a diagram illustrating the effect of the pulsation suppression voltage distribution ratio in Embodiment 2 of this disclosure. Additionally, Figure 22 and Figure 23 This is a graph illustrating the effect of the distribution ratio of the ripple suppression voltage Vq_FF when Vdc1 > Vdc2. The relationship Vq1_limit > Vq2_limit holds true for the q-axis voltage limits.

[0252] Here, as Figure 22 As shown, when Kv = 0.5, Vq_FF1 = Vq_FF2 holds true. When the q-axis voltage command values ​​(Vq1″, Vq2″) after applying the pulsation suppression voltage reach their limits (Vq1_limit, Vq2_limit), the first voltage command value Vq1′ is limited to "Vq1_limit - Vq_FF1", and the second voltage command value Vq2′ is limited to "Vq2_limit - Vq_FF2". Here, since Vq_FF1 = Vq_FF2, the difference between Vq1_limit and Vq2_limit directly becomes the difference ΔVq between the first voltage command value Vq1′ and the second voltage command value Vq2′. In contrast, as... Figure 23 As shown, when Kv = 0.8, Vq_FF1 > Vq_FF2. Therefore, with Figure 22 Compared to the situation shown, the difference ΔVq between the first voltage command value Vq1′ and the second voltage command value Vq2′ becomes smaller.

[0253] The first voltage command value Vq1′ is the voltage that becomes the source of the q-axis component Iq1 of the first detected current, and the second voltage command value Vq2′ is the voltage that becomes the source of the q-axis component Iq2 of the second detected current. Therefore, the difference ΔVq between the first voltage command value Vq1′ and the second voltage command value Vq2′ is the difference ΔIq between Iq1 and Iq2. In this embodiment, as... Figure 23 As shown, ΔIq is reduced by decreasing the pulsation suppression voltage ΔVq. By reducing ΔIq, the imbalance between the excitation force generated by the first drive current and the excitation force generated by the second drive current is reduced, thereby reducing the vibration and noise generated by the AC motor 1. Furthermore, the pulsation suppression current is also... Figure 19 and Figure 20 As shown, by making it vary according to Vdc1-Vdc2, the relationship of Kv=Ki can be maintained, thereby maintaining the effect described in Implementation 1.

[0254] [Implementation Method 3]

[0255] Figure 24 This is a block diagram showing the main structural components of the motor control device according to Embodiment 3 of this disclosure. Additionally, in Figure 24 In China, for the sake of Figure 1 and Figure 14 Structures that are identical to those shown are labeled with the same reference numerals. Furthermore, in this embodiment, descriptions of structures identical to those described in Embodiment 1 and Embodiment 2 are omitted.

[0256] The motor control device involved in this embodiment and Figure 14 The difference in the motor control device shown is that a voltage limiting unit 30000a is provided in controller 6a, and a voltage limiting unit 30000b is provided in controller 6b. Furthermore, this embodiment differs from embodiment 2 in that it sets Id_target1 = Id_target2 and Iq_target1 = Iq_target2.

[0257] The voltage limiting unit 30000a limits the first voltage command values ​​(voltage command values ​​Vd1, Vq1) output from the current controllers 12a and 13b using the first power supply voltage Vdc1 and the second power supply voltage Vdc2, and outputs the limited first voltage command values ​​Vd1′, Vq1′.

[0258] Figure 25This diagram illustrates the operation of the voltage limiting unit included in the motor control device according to Embodiment 3 of this disclosure. Here, the magnitude relationship between the first power supply voltage Vdc1 and the second power supply voltage Vdc2 is set as Vdc1 > Vdc2. Currently, it is assumed that the first voltage command value (voltage command value Vd1, Vq1) is limited by the voltage limiting circle of the first power supply voltage Vdc1.

[0259] The voltage limiting unit 30000a uses the lower of the first power supply voltage Vdc1 and the second power supply voltage Vdc2 for limiting. Here, since Vdc1 > Vdc2, the voltage vector is limited to the voltage limiting circle relative to the second power supply voltage Vdc2 (see reference). Figure 25 The voltage limiting unit 30000a outputs the d-axis component Vd1′ and q-axis component Vq1′ of the limited voltage vector as the first voltage command value after limitation.

[0260] The voltage limiting unit 30000b limits the second voltage command values ​​(voltage command values ​​Vd2, Vq2) output from the current controllers 12b and 12b using the lower of the first power supply voltage Vdc1 and the second power supply voltage Vdc2 (minimum power supply voltage), and outputs the limited second voltage command values ​​Vd2′, Vq2′.

[0261] Figure 26 This diagram illustrates the operation of the voltage limiting unit included in the motor control device according to Embodiment 3 of this disclosure. Here, the magnitude relationship between the first power supply voltage Vdc1 and the second power supply voltage Vdc2 is set as Vdc1 > Vdc2. Currently, it is assumed that the second voltage command value (voltage command value Vd2, Vq2) is limited by the voltage limiting circle of the second power supply voltage Vdc2.

[0262] The voltage limiting unit 30000b limits the voltage using the lower of the first power supply voltage Vdc1 and the second power supply voltage Vdc2 (the minimum power supply voltage). Here, since Vdc1 > Vdc2, the original limit value is output. As a result, the limited second voltage command values ​​Vd2′ and Vq2′ output from the voltage limiting unit 30000b are consistent with the second voltage command values ​​(voltage command values ​​Vd2 and Vq2).

[0263] Figure 27 This is a diagram illustrating the effect of the pulsation suppression voltage distribution ratio in Embodiment 3 of this disclosure. In this embodiment, both the limited first voltage command value and the limited second voltage command value are limited by the lower of the first power supply voltage Vdc1 and the second power supply voltage Vdc2, and therefore they are consistent. That is, Vd1′=Vd2′ and Vq1′=Vq2′ hold true.

[0264] Therefore, as Figure 27 As shown, even when the first pulsation suppression voltage Vq_FF1 = 0.8Vq_FF and the second pulsation suppression voltage Vq_FF2 = 0.2Vq_FF, Vq1′ is consistent with Vq2′. Therefore, ΔVq = 0 (and due to the voltage limiting unit, ΔVd = Vd1′ - Vd2′ = 0 also holds true). Compared to the structure of Embodiment 2, the imbalance between the excitation force generated by the first driving current and the excitation force generated by the second driving current is further reduced, thereby achieving the effect of reducing vibration and noise generated by the AC motor 1.

[0265] [Implementation Method 4]

[0266] Figure 28 This is a block diagram showing the main structural components of the motor control device according to Embodiment 4 of this disclosure. Additionally, in Figure 28 In the middle, to and Figure 1 , Figure 14 , Figure 24 Structures that are identical to those shown are labeled with the same reference numerals. Furthermore, in this embodiment, descriptions of structures identical to those described in embodiments 1-3 are omitted.

[0267] The motor control device involved in this embodiment and Figure 24 The difference in the motor control device shown is that controller 6c replaces controller 6a, and controller 6d replaces controller 6b. Controller 6c is replaced by a first cancellation calculation unit 500c. Figure 24 The controller 6a shown has the structure of the first cancellation calculation unit 500a. The controller 6d replaces this with a second cancellation calculation unit 500d. Figure 24 The structure of the second cancellation calculation unit 500b in the controller 6b shown is illustrated. Furthermore, in this embodiment, similar to Embodiment 3, Id_target1 = Id_target2 and Iq_target1 = Iq_target2 are set.

[0268] Figure 29 This is a block diagram showing the internal structure of the first cancellation calculation unit included in the motor control device according to Embodiment 4 of this disclosure. Furthermore, in Figure 29 In the middle, to and Figure 5 and Figure 15 Structures with the same structure are labeled with the same reference numerals. For example... Figure 29 As shown, the first cancellation calculation unit 500c and Figure 15The difference in the first cancellation calculation unit 500a shown is that a first pulsation suppression voltage distribution ratio setter 10000c is set to replace the first pulsation suppression voltage distribution ratio setter 10000a, and a first pulsation suppression current distribution ratio setter 20000c is set to replace the first pulsation suppression current distribution ratio setter 20000a.

[0269] Figure 30 This diagram illustrates the operation of the first pulsation suppression voltage distribution ratio setter included in the motor control device according to Embodiment 4 of this disclosure. Additionally, Figure 30 In the chart shown, the horizontal axis represents the voltage limit difference ΔVq_limit as shown in equation (4-1), and the vertical axis represents the first ripple suppression voltage Vq_FF1 (=Kv). Vq_FF).

[0270] [Mathematical Expression 39]

[0271] Here, the first pulsation suppression voltage distribution ratio setter 10000c performs the following operations as shown in equations (4-2) and (4-3) to obtain the first voltage limit value Vq_limit1 and the second voltage limit value Vq_limit2 in equation (4-1) above.

[0272] [Mathematical Expression 40]

[0273] However, besides the calculations shown in equations (4-2) and (4-3) above, the first voltage limit value Vq_limit1 and the second voltage limit value Vq_limit2 can also be obtained through Taylor expansion or Maclaurin expansion. Alternatively, a table representing the relationship between the first power supply voltage Vdc1, the second power supply voltage Vdc2, the first voltage command value Vd1′, and the first voltage limit value Vq_limit1 and the second voltage limit value Vq_limit2 can be created in advance, and the first voltage limit value Vq_limit1 and the second voltage limit value Vq_limit2 can be obtained using this table.

[0274] like Figure 30As shown, the first ripple suppression voltage allocation ratio setter 10000c is set such that if the voltage limit difference ΔVq_limit (=Vq_limit1-Vq_limit2) exceeds the positive ripple suppression voltage Vq_FF, it outputs "Vq_FF1=Vq_FF (Kv=1)"; if the voltage limit difference ΔVq_limit (=Vq_limit1-Vq_limit2) is lower than the negative ripple suppression voltage -Vq_FF, it outputs "Vq_FF1=0.0 (Kv=0)". Furthermore, the first ripple suppression voltage allocation ratio setter 10000c is set such that if the voltage limit difference ΔVq_limit (=Vq_limit1-Vq_limit2) is above the negative ripple suppression voltage -Vq_FF and below the positive ripple suppression voltage Vq_FF, then Vq_FF1 continuously varies from 0 to Vq_FF. Specifically, if Vdc1 = Vdc2 (the first power supply voltage and the second power supply voltage are equal), then the voltage limit difference ΔVq_limit shown in equation (4-1) above is 0, and the output is "Vq_FF1 = 0.5Vq_FF (Kv = 0.5)". That is, if the first power supply voltage and the second power supply voltage are equal, then the first ripple suppression voltage and the second ripple suppression voltage are equal, and half of the ripple suppression voltage is output.

[0275] Therefore, the output value Vq_FF1 of the first pulsation suppression voltage distribution ratio setter 10000c is represented by the following equation (4-4).

[0276] [Mathematical Expression 41]

[0277] Here, Kv (the allocation ratio of pulsation suppression voltage Vq_FF to first pulsation suppression voltage Vq_FF1) of the first pulsation suppression voltage allocation ratio setter 10000c is represented by the following equation (4-5). In the following equation (4-5), when Kv is less than 0 or greater than 1, it is limited to 0≦Kv≦1.

[0278] [Mathematical Expression 42]

[0279] Figure 31This diagram illustrates the operation of the first pulsation suppression current distribution ratio setter included in the motor control device according to Embodiment 4 of this disclosure. The operation of the first pulsation suppression current distribution ratio setter 20000c is essentially the same as the operation of the first pulsation suppression voltage distribution ratio setter 10000c. Therefore, the description of the operation of the first pulsation suppression current distribution ratio setter 20000c is omitted. Furthermore, Ki (the distribution ratio of pulsation suppression current i_cancel2 to first pulsation suppression current I_cancel_a) of the first pulsation suppression current distribution ratio setter 20000c is represented by a formula in equation (4-5) above, where Vq_FF is replaced by i_cancel2. Wherein, when Ki is less than 0 or greater than 1, it is limited to 0 ≤ Ki ≤ 1.

[0280] Figure 32 This is a block diagram showing the internal structure of the second cancellation calculation unit included in the motor control device according to Embodiment 4 of this disclosure. Furthermore, in Figure 32 In the middle, to and Figure 5 and Figure 18 Structures with the same structure are labeled with the same reference numerals. For example... Figure 32 As shown, the second cancellation calculation unit 500d and Figure 18 The difference in the second cancellation calculation unit 500b shown is that a second ripple suppression voltage distribution ratio setter 10000d is provided instead of the second ripple suppression voltage distribution ratio setter 10000b, and a second ripple suppression current distribution ratio setter 20000d is provided instead of the second ripple suppression current distribution ratio setter 20000b.

[0281] Figure 33 This diagram illustrates the operation of the second pulsation suppression voltage distribution ratio setter included in the motor control device according to Embodiment 4 of this disclosure. Additionally, Figure 33 In the chart shown, the horizontal axis represents the voltage limit difference ΔVq_limit (=Vq_limit1-Vq_limit2), and the vertical axis represents the second ripple suppression voltage Vq_FF2 (=(1-Kv)). Vq_FF).

[0282] like Figure 33As shown, the second ripple suppression voltage allocation ratio setter 10000d is set such that if the voltage limit difference ΔVq_limit (=Vq_limit1-Vq_limit2) exceeds the positive ripple suppression voltage Vq_FF, it outputs "Vq_FF2=0 (Kv=1)"; if the voltage limit difference ΔVq_limit (=Vq_limit1-Vq_limit2) is lower than the negative ripple suppression voltage -Vq_FF, it outputs "Vq_FF2=Vq_FF (Kv=0)". Furthermore, the second ripple suppression voltage allocation ratio setter 10000d is set such that if the voltage limit difference ΔVq_limit (=Vq_limit1-Vq_limit2) is above the negative ripple suppression voltage -Vq_FF and below the positive ripple suppression voltage Vq_FF, then Vq_FF2 continuously varies from Vq_FF to 0.

[0283] Therefore, the output value Vq_FF2 of the second pulsation suppression voltage distribution ratio setter 10000d is represented by the following equation (4-6).

[0284] [Mathematical Expression 43]

[0285] Furthermore, from equations (4-4) and (4-6) above, we obtain equation (4-7), which holds true. Figure 35 The relationship shown.

[0286] [Mathematical Expression 44]

[0287] Figure 35 It is Figure 30 The characteristics shown are Figure 33 The diagram shows the synthesized characteristics. Specifically, Figure 35 It is Figure 30 The characteristics of the first ripple suppression voltage Vq_FF1 relative to the voltage limit difference ΔVq_limit shown are similar to... Figure 33 The graph shown is a composite of the characteristics of the second ripple suppression voltage Vq_FF2 relative to the voltage limit difference ΔVq_limit. Figure 35 As shown, the sum of the first pulsation suppression voltage Vq_FF1 and the second pulsation suppression voltage Vq_FF2 is always equal to the pulsation suppression voltage Vq_FF.

[0288] Figure 34This diagram illustrates the operation of the second pulsation suppression current distribution ratio setter included in the motor control device according to Embodiment 4 of this disclosure. The operation of the second pulsation suppression current distribution ratio setter 20000d is essentially the same as the operation of the second pulsation suppression voltage distribution ratio setter 10000d. Therefore, the description of the operation of the second pulsation suppression current distribution ratio setter 20000d is omitted.

[0289] Figure 36 This diagram illustrates the operation of the voltage limiting unit included in the motor control device according to Embodiment 4 of this disclosure. Here, the relationship between the magnitudes of the first power supply voltage Vdc1 and the second power supply voltage Vdc2 is... Figure 25 and Figure 26 Similarly, Vdc1 > Vdc2. Furthermore, Vd1′ = Vd2′ is set here. Therefore, considering Vd1′ and Vd2′, there is a limitation that the q-axis voltage of the first inverter 4a can only be output to the voltage limit value Vq_limit1, and the q-axis voltage of the second inverter 4b can only be output to the voltage limit value Vq_limit2 (hereinafter referred to as the "first limit").

[0290] Furthermore, while satisfying the first limitation mentioned above, a first pulsation suppression voltage Vq_FF1 and a second pulsation suppression voltage Vq_FF2 must be applied to satisfy equation (4-7) above, and a first voltage command value Vq1′ and a second voltage command value Vq2′ must be set to satisfy ΔVq=(Vq1′-Vq2′)=0. Additionally, applying the first pulsation suppression voltage Vq_FF1 and the second pulsation suppression voltage Vq_FF2 to satisfy equation (4-7) above is a limitation for suppressing N torque pulsations generated by the AC motor 1 (hereinafter referred to as the "second limitation"). Furthermore, setting the first voltage command value Vq1′ and the second voltage command value Vq2′ to satisfy ΔVq=(Vq1′-Vq2′)=0, as explained in Embodiment 3, is a limitation for suppressing the imbalance between the excitation force generated by the first drive current and the excitation force generated by the second drive current (hereinafter referred to as the "third limitation").

[0291] Here, based on the first limitation mentioned above, the voltage Vq1″ output from adder 100a is subject to the limitation shown in equation (4-8), and the voltage Vq2″ output from adder 100b is subject to the limitation shown in equation (4-9). Furthermore, voltage Vq1″ is a voltage superimposed with the first ripple suppression voltage Vq_FF1, and voltage Vq2″ is a voltage superimposed with the second ripple suppression voltage Vq_FF2.

[0292] [Mathematical Expression 45]

[0293] Here, the first voltage command value Vq1′ before the first ripple suppression voltage Vq_FF1 is applied is given by the following equation (4-10). In addition, the second voltage command value Vq2′ before the second ripple suppression voltage Vq_FF2 is applied is given by the following equation (4-11).

[0294] [Mathematical Expression 46]

[0295] [Mathematical Expression 47]

[0296] Next, for equation (4-10) above, considering equation (4-4) above, the voltage Vq1″ after superimposing the pulsation suppression voltage is expressed by equation (4-12) below. Furthermore, for equation (4-11) above, if equation (4-6) above is considered, the voltage Vq2″ after superimposing the pulsation suppression voltage is expressed by equation (4-12) below.

[0297] [Mathematical Expression 48]

[0298] [Mathematical Expression 49]

[0299] It can be seen that by giving the first voltage command value Vq1′ and the second voltage command value Vq2′ as in equations (4-10) and (4-11) above, the second restriction is satisfied, and it can also be seen from equations (4-12) and (4-13) above that the third restriction is also satisfied.

[0300] In other words, in the voltage Vq1″ after the ripple suppression voltage is superimposed, when the condition "Vq_FF < ΔVq_limit" is met, "Vq1″ = Vq_limit2 + Vq_FF", which is less than "Vq_limit1". This is to satisfy the restriction of the second condition. Furthermore, when "ΔVq_limit" is greater than "Vq_FF", if the output is to Vq1″ = Vq_limit1, then the second and third conditions are not satisfied. Under other conditions, Vq1″ can be set to Vq_limit1 (the limit of the output to the first inverter 4a).

[0301] Furthermore, in the voltage Vq2″ after the ripple suppression voltage is superimposed, when the condition "ΔVq_limit < -Vq_FF (if the formula is transformed, then Vq_FF < Vq_limit2 - Vq_limit1)" is met, "Vq2″ = Vq_limit1 + Vq_FF", which is less than "Vq_limit2". This is to satisfy the restriction of the second condition. Additionally, when "Vq_limit2 - Vq_limit1" is greater than "Vq_FF", if the output is to Vq2″ = Vq_limit2, then the second and third conditions are not satisfied. Under other conditions, it can be set as Vq2″ = Vq_limit2 (the limit of the output to the second inverter 4b).

[0302] As described above, in this embodiment, since the first to third limitations are satisfied, even when there is a difference between the first power supply voltage and the second power supply voltage, a quiet motor control device that suppresses noise generated by the AC motor 1 can be provided. Furthermore, the noise generated by the AC motor 1 includes noise caused by N-fold torque pulsation at the electrical angle, and noise caused by the imbalance between the excitation force generated by the first drive current and the excitation force generated by the second drive current.

[0303] By implementing the above-described embodiments 1 to 4, torque ripple generated by a motor with two winding groups can be reduced, thereby balancing the "reliability (fail-resistance) requirements of the motor control device" and "improved motor quietness".

[0304] [Implementation Method 5]

[0305] Figure 37 This is a diagram showing the main structural components of the electric power steering system according to Embodiment 5 of this disclosure. (See diagram for example.) Figure 37 As shown, the electric power steering system 50 includes a steering wheel 51, a steering shaft 52, a rack and pinion 53, a wheel 54, a connecting rod 55, a steering knuckle arm 56, a torque detector 57, a rotation detector 58, a motor 59, and a motor control device 60.

[0306] The steering wheel 51, also known as the steering wheel, is operated by the driver of the vehicle (not shown) and is used to apply a steering angle to the steering wheels (wheels 54). The steering shaft 52 consists of an input shaft 52a connected to the side of the steering wheel 51 and an output shaft 52b connected to the side of the rack and pinion 53. The input shaft 52a and the output shaft 52b are connected to each other by a torsion bar (not shown).

[0307] A torsion bar is disposed within a torque detector 57 and extends axially through the torque detector 57. The torsion bar twists according to the steering torque applied to the steering wheel 51 by the driver's operation, and the torque detector 57 detects the direction and amount of this twist. Hereinafter, the steering wheel 51, steering shaft 52, and torsion bar are collectively referred to as the "steering gear".

[0308] The rack and pinion 53 includes a pinion (not shown) mounted at the front end of the output shaft 52b and a rack (not shown) meshing with the pinion, converting the rotational motion of the pinion into reciprocating motion. The rack and wheel 54 are connected via a connecting rod 55 and a steering knuckle arm 56.

[0309] Torque detector 57 detects the steering torque applied to the torsion bar by the driver steering the steering wheel 51. When steering torque is applied, a torsion approximately proportional to the steering torque is generated in the torsion bar. Torque detector 57 detects this torsion angle and converts it into steering torque. Rotation detector 58 is mounted on the rotation shaft of motor 59 and detects the rotational position of the rotation shaft.

[0310] Under the control of the control device 60, the motor 59 generates a steering assist torque relative to the steering gear. The motor 59 is, for example, an AC motor or a DC motor such as a permanent magnet synchronous motor or an induction motor. The motor control device 60 controls the motor 59 to generate a steering assist torque relative to the steering gear based on the steering torque calculated by the torque detector 57 and the rotational position detected by the rotation detector 58.

[0311] Here, for example, the motor 59 is the AC motor 1 described in Embodiments 1 to 4, and the rotation detector 58 is the position detector 2 described in Embodiments 1 to 4. Furthermore, the motor control device 60 is the motor control device described in Embodiments 1 to 4. Therefore, the electric power steering device 50 according to this embodiment can reduce torque pulsation generated by the motor 59 having two winding sets, thereby improving reliability and quietness.

[0312] While the embodiments of this disclosure have been described above, this disclosure is not limited to the above embodiments and can be freely modified within the scope of the spirit of this disclosure. For example, the above embodiments 1 to 4 can be appropriately combined in any way.

[0313] Furthermore, in embodiments 1 to 4, an example was described in which current command values ​​(Id_target, Iq_target, Id_target1, Iq_target1, Id_target2, Iq_target2) were input to the cancellation calculation unit. However, the first detection current (Id1, Iq1) detected by the current detector 5a and the second detection current (Id2, Iq2) detected by the current detector 5b may be used instead of the aforementioned current command values ​​as the current signals input to the cancellation calculation unit.

[0314] Here, it is believed that when the first and second detection currents detected by current detectors 5a and 5b are used instead of the above-mentioned command values, the high-frequency noise superimposed on the first and second detection currents will adversely affect the operation in the cancellation calculation unit. In order to avoid this adverse effect, the current signal after applying a low-pass filter to remove the high-frequency noise from the first detection current (Id1, Iq1) or the second detection current (Id2, Iq2) can be used as the current signal input to the cancellation calculation unit.

[0315] Furthermore, in embodiments 1 to 4, the rotational position θ input to the cancellation calculation unit can be the detection result of the rotational position sensor, or it can be an estimated rotational position θ obtained by control without a known rotational position sensor.

[0316] Furthermore, the controller 6 in Embodiment 1, the first controller 6a and the second controller 6b in Embodiments 2 and 3, and the first controller 6c and the second controller 6d in Embodiment 4 can also be implemented through the cooperation of software and hardware resources. That is, it can also be implemented by recording the programs used to implement each function on a computer-readable recording medium, and having the computer system read and execute the programs recorded on the recording medium.

[0317] Label Explanation

[0318] 1...AC motor, 2...position detector, 3, 3a, 3b...DC power supply, 4a...first inverter, 4b...second inverter, 5a, 5b...current detector, 6, 6a, 6b...controller, 50...electric power steering, 57...torque detector, 59...motor, 60...motor control unit, Icancel_a...first pulsation suppression current, Icancel_b...second pulsation suppression current, Id_target, Iq_target...current command value, Id_target1, Iq_target1...current command value, I d_target2, Iq_target2... Current command values, Iu1, Iv1, Iw1... Current, Iu2, Iv2, Iw2... Current, UV1, VW1, UW1... First three-phase winding group, UV2, VW2, UW2... Second three-phase winding group, Vd1, Vq1... Voltage command values, Vd2, Vq2... Voltage command values, Vq_FF... Pulse suppression voltage, Vq_FF1... First pulsation suppression voltage, Vq_FF2... Second pulsation suppression voltage, Vu1, Vv1, Vw1... Voltage command values, Vu2, Vv2, Vw2... Voltage command values.

Claims

1. A motor control device that controls a motor having two winding groups by respectively applying a first drive current output from a first inverter and a second drive current output from a second inverter to two winding groups, the motor control device being characterized in that it comprises: The controller superimposes a pulsation suppression voltage, calculated based on the rotational position of the motor and designed to reduce the pulsation component in the torque generated by the motor, onto at least one of a first voltage command value corresponding to the output voltage of the first inverter and a second voltage command value corresponding to the output voltage of the second inverter.

2. The motor control device as described in claim 1, characterized in that, The controller sets the allocation ratio for distributing the ripple suppression voltage to the first inverter and the second inverter, and superimposes the ripple suppression voltage corresponding to the allocation ratio onto the first voltage command value and the second voltage command value.

3. The motor control device as described in claim 2, characterized in that, The controller includes: A first controller calculates the first voltage command value based on a current command value that is a command value for the first drive current and the second drive current, and a first detection current that is a detection current for the first drive current; and The second controller calculates the second voltage command value based on the current command value and the second detection current, which is the detection current used as the second drive current. At least one of the first controller and the second controller adds a pulsation suppression current, which reduces the pulsation component contained in the torque, to the current command value.

4. The motor control device as described in claim 3, characterized in that, The controller makes the allocation ratio of the ripple suppression voltage to the first inverter and the second inverter consistent with the ratio of the ripple suppression current superimposed by the first controller on the current command value and the ripple suppression current superimposed by the second controller on the current command value.

5. The motor control device as described in any one of claims 2 to 4, characterized in that, When the DC power supply voltage input to the first inverter (i.e., the first power supply voltage) is higher than the DC power supply voltage input to the second inverter (i.e., the second power supply voltage), the controller sets the allocation ratio such that the amount of ripple suppression voltage allocated to the first inverter is greater than the amount allocated to the second inverter. When the second power supply voltage is higher than the first power supply voltage, the allocation ratio is set such that the amount of ripple suppression voltage allocated to the second inverter is greater than the amount allocated to the first inverter.

6. The motor control device as described in claim 5, characterized in that, The controller operates based on the voltage difference between the first power supply voltage and the second power supply voltage, and adjusts the allocation ratio according to the voltage difference.

7. The motor control device as described in any one of claims 1 to 4, characterized in that, When the controller sets the lower of the DC power supply voltage input to the first inverter (i.e., the first power supply voltage) and the DC power supply voltage input to the second inverter (i.e., the second power supply voltage) as the minimum power supply voltage, it limits the first voltage command value and the second voltage command value using a threshold based on the minimum power supply voltage.

8. The motor control device as described in claim 3 or 4, characterized in that, The controller includes a pulsation suppression voltage calculation unit that calculates the pulsation suppression voltage. The amplitude of the pulsation suppression voltage is proportional to the pulsation suppression current and the rotational speed of the motor, and the phase is 0 degrees or more and 90 degrees ahead of one cycle of the pulsation suppression current.

9. The motor control device as described in claim 8, characterized in that, The pulsation suppression voltage calculation unit calculates the pulsation suppression voltage based on the interference suppression current, which suppresses the interference current generated based on the pulsation component of the motor's magnetic flux.

10. An electric power steering apparatus characterized by comprising: include: Torque detector, which detects the steering torque of the steering gear; The motor has two winding groups respectively supplied with a first drive current output from a first inverter and a second drive current output from a second inverter, and generates steering assist torque for the steering gear. as well as The motor control device according to any one of claims 1 to 9, wherein the motor control device controls the drive of the motor based on the steering torque detected by the torque detector.

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