JP6658041B2 - Motor control device and electric power steering device equipped with the same - Google Patents

Description

  The present invention relates to a motor control device that drives and controls a motor based on a current command value for a motor, and in particular, learns the characteristics of harmonic components and compensates for the current command value by using the learning result to cause the harmonic component. The present invention relates to a motor control device capable of coping with the inconvenience and an electric power steering device equipped with the motor control device.

  2. Description of the Related Art An electric power steering device (EPS) that includes a motor control device and applies a steering assisting force (assisting force) to a steering mechanism of a vehicle by a rotational force of a motor is provided by a motor or a driving device via a speed reducer. , A steering assist force is applied to the steering shaft or the rack shaft. Such a conventional electric power steering device performs feedback control of a motor current in order to accurately generate a torque of a steering assist force. The feedback control is to adjust the motor applied voltage so that the difference between the current command value and the motor current detection value is small. Generally, the adjustment of the motor applied voltage is performed by adjusting the duty of PWM (pulse width modulation) control. We are making adjustments.

  A general configuration of the electric power steering apparatus will be described with reference to FIG. 1. A column shaft (steering shaft, handle shaft) 2 of a handle 1 includes a reduction gear 3, universal joints 4 a and 4 b, a pinion rack mechanism 5, a tie rod 6 a, 6b, and further connected to steered wheels 8L, 8R via hub units 7a, 7b. The column shaft 2 is provided with a torque sensor 10 for detecting the steering torque of the steering wheel 1 and a steering angle sensor 14 for detecting the steering angle θ, and a motor 20 for assisting the steering force of the steering wheel 1 is provided with a reduction gear 3. Through the column shaft 2. A control unit (ECU) 30 that controls the electric power steering device is supplied with electric power from a battery 13 as a power supply, and receives an ignition key (IG) signal via an ignition key 11. The control unit 30 calculates a current command value of an assist (steering assist) command based on the steering torque Th detected by the torque sensor 10 and the vehicle speed Vel detected by the vehicle speed sensor 12, and calculates the calculated current command value. The current supplied to the motor 20 is controlled by the voltage command value Vref obtained by compensating the above. The steering angle sensor 14 is not essential and may not be provided, and can be obtained from a rotation angle sensor such as a resolver connected to the motor 20.

  The control unit 30 is connected to a CAN (Controller Area Network) 40 for transmitting and receiving various information of the vehicle, and the vehicle speed Vel can be received from the CAN 40. The control unit 30 can also be connected to a non-CAN 41 other than the CAN 40 for transmitting and receiving communications, analog / digital signals, radio waves, and the like.

  The control unit 30 is mainly composed of an MCU (including a CPU and an MPU), but a general function executed by a program inside the MCU is, for example, as shown in FIG. .

  The function and operation of the control unit 30 will be described with reference to FIG. 2. The steering torque Th detected by the torque sensor 10 and the vehicle speed Vel detected by the vehicle speed sensor 12 (or from the CAN 40) are calculated by a current command value calculation unit 31. The current command value calculator 31 calculates a current command value Iref, which is a control target value of the motor current supplied to the motor 20, using an assist map or the like based on the steering torque Th and the vehicle speed Vel. The calculated current command value Iref is input to the current limiting unit 33 via the adding unit 32A, and the current command value Irefm whose maximum current is limited is input to the subtracting unit 32B, and the deviation from the motor current value Im being fed back. I (= Irefm-Im) is calculated, and the deviation I is input to a PI (proportional-integral) controller 35 for improving the characteristics of the steering operation. The voltage command value Vref whose characteristics have been improved by the PI control unit 35 is input to the PWM control unit 36, and the motor 20 is PWM-driven via an inverter 37 as a drive unit. The motor current value Im of the motor 20 is detected by the motor current detector 38 and fed back to the subtractor 32B. The inverter 37 uses an FET (field effect transistor) as a drive element, and is configured by a bridge circuit of the FET. A rotation angle sensor 21 such as a resolver is connected to the motor 20, and the rotation angle θe is detected and output.

  The compensation signal CM from the compensation signal generation unit 34 is added to the addition unit 32A, and the characteristics of the steering system are compensated by adding the compensation signal CM, so that the convergence and the inertia characteristics are improved. . The compensation signal generating unit 34 adds the self-aligning torque (SAT) 343 and the inertia 342 in the adding unit 344, further adds the convergence 341 to the addition result in the adding unit 345, and compensates the addition result of the adding unit 345. The signal CM is used.

  In such an electric power steering device, the motor current to be fed back usually includes a harmonic component in addition to a fundamental component, and a torque ripple is generated due to the harmonic component, and vibration and noise are reduced. This is one of the factors. The effect of the harmonic component is non-linear, and a technique for controlling the non-linearity of the motor by modeling the non-linearity is not limited to the effect of the harmonic component. For example, in a motor control device disclosed in Japanese Patent No. 5351345 (Patent Document 1), a non-linearity of a motor is modeled using a virtual motor that simulates a real motor. The virtual motor adopts a non-linear behavior model (a model in which the internal structure is described as a black box to describe input / output characteristics), and is expressed by a voltage equation, a Fleming equation, and a motion equation. Then, the virtual motor is mounted together with the real motor and operated together, so that the real motor can be controlled with high accuracy from the beginning of the transition from the rest period to the exercise period. In addition, data indicating the operating state of the motor, such as the motor position used to control the motor, can be obtained from the virtual motor instead of the real motor, in which case a sensor for detecting the operating state is not required. Can be

Japanese Patent No. 5351345

  However, in the device of Patent Document 1, since the entire motor is modeled, the amount of data for defining a virtual motor as a model increases, and when a mass-produced microcomputer is used, there is a concern that memory capacity is insufficient. Is done. There is a possibility that the amount of calculation may increase, and if the amount of data and the amount of calculation are reduced, the accuracy of the model may decrease.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the required amount of memory, cope with the nonlinearity caused by the change in the operating point of the motor, and generate the harmonics caused by the harmonic components. It is an object of the present invention to provide a motor control device capable of coping with the problem described above and an electric power steering device equipped with the motor control device.

The present invention relates to a motor control device that drives and controls the motor based on a current command value for the motor, and the object of the present invention is to learn characteristics of at least one harmonic component of a magnetic flux of a magnetic field generated by the motor. A harmonic model unit configured to calculate a compensation command value from the current command value using a motor angular velocity of the motor by the model, wherein the harmonic model unit includes a harmonic component of the magnetic flux corresponding to the current command value. This is achieved by calculating the compensation command value using a motor feature value conversion table in which the value is determined, and controlling the driving of the motor based on the current command value and the compensation command value.

Further, the above object of the present invention further comprises a current control unit for calculating a voltage command value for controlling a current supplied to the motor based on the current command value, wherein the voltage command compensated by the compensation command value is provided. by driving and controlling the motor based on the value, or by compensating for the voltage command value by adding the compensation command value, the harmonic model unit some have is, in polar coordinates the current command value A polar coordinate conversion unit for converting, a magnetic flux calculation unit for obtaining a harmonic component of the magnetic flux corresponding to the current command value converted to the polar coordinate by the motor feature quantity conversion table, a harmonic component of the magnetic flux and the motor angular velocity And a compensation command value calculation unit for calculating the compensation command value using the above, or by including at least a fifth harmonic as the harmonic component. Or by use in an electric power steering device for assisting control of the steering system by driving the motor, it is more effectively achieved.

  Further, the above object is achieved by an electric power steering device equipped with the motor control device.

  ADVANTAGE OF THE INVENTION According to the motor control apparatus of this invention, the object to be modeled is narrowed down to motor features such as magnetic flux that characterizes the nonlinearity of the motor while utilizing existing sensors, and the characteristics of harmonic components of the motor features are learned. Therefore, since the voltage command value is compensated, the required amount of memory can be suppressed, the torque ripple generated due to the harmonic component can be reduced, and the vibration and noise generated due to the torque ripple can be suppressed.

  Further, by mounting the motor control device in an electric power steering device, an electric power steering device with less vibration and noise can be provided.

1 is a configuration diagram illustrating an outline of an electric power steering device. FIG. 2 is a block diagram illustrating a configuration example of a control system of the electric power steering device. FIG. 2 is a block diagram illustrating a configuration example (first embodiment) of the present invention. FIG. 4 is a characteristic diagram illustrating an example of an assist map used in a current command value calculation unit. It is a block diagram showing an example of composition of a harmonic model part. 4 is a flowchart illustrating an operation example (first embodiment) of the present invention. 5 is a flowchart illustrating an operation example of a harmonic model unit. It is a block diagram showing the example of composition (2nd embodiment) of the present invention. It is a flowchart which shows the operation example (2nd Embodiment) of this invention. It is a characteristic diagram which shows the example which represented the motor feature-value conversion table by the broken line approximation, (A) is a characteristic diagram of the magnetic flux amplitude with respect to a current amplitude, (B) is a characteristic diagram of the magnetic flux phase with respect to a current amplitude.

  In the present invention, a harmonic component of a physical quantity (motor feature quantity) characterizing the non-linearity of the motor, such as a magnetic flux and an inductance generated by the motor, is modeled (hereinafter, this model is referred to as a “harmonic model”). The compensation command value is calculated from the current command value using the detected data such as the rotation angle (motor information) and the harmonic model, and the voltage command value is compensated by the compensation command value. Normally, the current command value is set based on the fundamental wave of the motor current. Therefore, when the motor current includes harmonics, a mismatch occurs between the current command value and the set current command value, and the torque caused by the harmonics is generated. Ripple occurs. However, in the present invention, by compensating the voltage command value using a harmonic model that models the harmonic component of the motor feature closely related to the harmonic component of the motor current, the harmonic component is taken into account. Since the drive of the motor is controlled, torque ripple can be reduced. In addition, since only the motor feature amount is modeled instead of the entire motor, a necessary memory amount can be suppressed.

  A harmonic is a sine wave having a frequency that is an integral multiple of the fundamental wave. For example, a harmonic having a frequency that is five times the fundamental wave is called a fifth harmonic. The fundamental wave is the lowest frequency sine wave among various sine waves that constitute one non-sine wave (distorted wave). Harmonics with higher frequencies generate torque ripple. Adverse effects such as vibration and noise. Among the harmonics, the fifth and seventh harmonics are said to have a strong adverse effect, but depending on the cause of the generation of harmonics, the harmonics of other orders may have a strong adverse effect. In the present invention, it is possible to cope with harmonics of an arbitrary order.

  The harmonic model has a motor feature value conversion table that defines the correspondence between the current command value and the high frequency component of the motor feature value. For example, when a magnetic flux is used as a motor feature value, the amplitude of a current command value (hereinafter, referred to as “current amplitude”) and the advance angle (hereinafter, “ The amplitude (hereinafter referred to as “magnetic flux amplitude”) and phase (hereinafter referred to as “magnetic flux phase”) of the harmonic component of the magnetic flux corresponding to “current advance angle”) are defined in the motor feature quantity conversion table. I have. Then, a compensation command value is calculated by differentiating the harmonic component of the magnetic flux.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 3 shows a configuration example (first embodiment) of the embodiment of the present invention in correspondence with FIG. 2, and the same components are denoted by the same reference numerals and detailed description is omitted.

  In the present embodiment, magnetic flux is used as the motor feature quantity, and the target harmonic is the fifth harmonic. The drive control target motor is a three-phase brushless motor, and the motor current is a three-phase (U-phase, V-phase, and W-phase) current, and is converted into a two-phase (d-axis and q-axis) current when fed back. Is converted. Using the motor angular velocity as the motor information, the harmonic model obtains a two-phase compensation command value from the two-phase current command value. Then, the two-phase voltage command value and the two-phase compensation command value calculated from the two-phase current command value are converted into three phases, respectively, to compensate the voltage command value. Note that the present embodiment does not include the current limiter 33 and the compensation signal generator 34 shown in FIG. 2, but may include them. In addition, a current control unit includes the PI control units 110 and 120 and the subtraction units 200 and 201.

  The current command value calculator 31 calculates the current command value Iref using the assist map based on the steering torque Th and the vehicle speed Vel, similarly to the configuration shown in FIG. As the assist map, for example, one having characteristics as shown in FIG. 4 is used. That is, as the steering torque Th increases, the current command value Iref also increases, but when the steering torque Th exceeds a predetermined value, the current command value Iref becomes constant. Also, the current command value Iref decreases as the vehicle speed Vel increases.

  The dq-axis current command value calculation unit 100 calculates a d-axis basic current command value Idref1 and a q-axis basic current command value Iqref1, which are current command values in the dq rotating coordinate system, using the current command value Iref and the motor angular velocity ωe. I do. The motor angular speed ωe is calculated by the motor angular speed calculation unit 170 from the rotation angle (electrical angle) θe detected by the rotation angle sensor 21 connected to the motor 20. The d-axis basic current command value Idref1 and the q-axis basic current command value Iqref1 are calculated by, for example, a method executed by a dq-axis current command value calculation unit described in Japanese Patent No. 5282376. The steering assist current command value in the publication corresponds to the current command value. At this time, if the motor angular velocity with respect to the mechanical angle of the motor is required, it is calculated based on the motor angular velocity ωe with respect to the electric angle.

  The harmonic model unit 130 is equivalent to a harmonic model, and calculates a d-axis compensation voltage command value Vdref5 and a q-axis compensation voltage command value, which are compensation command values, from the d-axis basic current command value Idref1 and the q-axis basic current command value Iqref1. Vqref5 is calculated. At this time, the motor angular velocity ωe calculated by the motor angular velocity calculation unit 170 is used as the motor information. However, since the harmonic model is for the fifth harmonic, the motor angular velocity ωe is used by multiplying it by five.

  FIG. 5 shows a configuration example of the harmonic model unit 130. The harmonic model unit 130 includes a polar coordinate conversion unit 131, a magnetic flux calculation unit 132, and a compensation command value calculation unit 133.

  The polar coordinate converter 131 converts the d-axis basic current command value Idref1 and the q-axis basic current command value Iqref1 into polar coordinates, and calculates a current amplitude Iap and a current advance angle βi. Specifically, it is calculated using the following equation (1).

ここで、arctan()は逆正接関数である。

Here, arctan () is the arctangent function.

  The magnetic flux calculation unit 132 obtains the amplitude (magnetic flux amplitude) φ5 and the phase (magnetic flux phase) α5 of the fifth harmonic component of the magnetic flux from the current amplitude Iap and the current advance angle βi. Specifically, the magnetic flux amplitude φ5 corresponding to the current amplitude Iap and the current advance angle βi and the magnetic flux phase α5 corresponding to the current amplitude Iap and the current advance angle βi are obtained by learning in advance by the finite element method, and are obtained by numerical data. It is stored as a motor feature quantity conversion table expressed in a series. Then, the magnetic flux amplitude φ5 and the magnetic flux phase α5 corresponding to the input current amplitude Iap and the current advance angle βi are obtained from the motor characteristic amount conversion table, and the magnetic flux amplitude φ5 is calculated by the compensation command value calculation unit 133, and the magnetic flux phase α5 is calculated by two phases. Output to the / 3 phase converter 150.

  The compensation command value calculation unit 133 calculates a d-axis compensation voltage command value Vdref5 and a q-axis compensation voltage command value Vqref5 using the magnetic flux amplitude φ5 and the motor angular velocity ωe. The induced voltage is obtained from the law of electromagnetic induction by differentiating the magnetic flux amplitude φ5 with time, and the d-axis compensation voltage command value Vdref5 and the q-axis compensation voltage command value Vqref5 correspond to the maximum value of the induced voltage. The d-axis compensation voltage command value Vdref5 and the q-axis compensation voltage command value Vqref5 are calculated by the following equation (2).

ここで、ｋ_ｄ及びｋ_ｑはそれぞれｄ軸補償電圧指令値Ｖｄｒｅｆ５及びｑ軸補償電圧指令値Ｖｑｒｅｆ５の振幅を決定する係数で、予め設定されている。

Here, k _d and k _q are coefficients that determine the amplitudes of the d-axis compensation voltage command value Vdref5 and the q-axis compensation voltage command value Vqref5, respectively, and are set in advance.

  The three-phase / two-phase conversion unit 160 uses the rotation angle θe detected by the rotation angle sensor 21 to output a motor current (U-phase motor current Ium, V phase) flowing through each phase of the motor 20 detected by the motor current detector 38. The phase motor current Ivm and the W-phase motor current Iwm) are converted into two-phase currents. Specifically, the three-phase motor current is converted into a two-phase current d-axis motor current Idm and a q-axis motor current Iqm according to the following equation (3).

Ｋは、絶対変換の場合は√（２／３）で、相対変換の場合は２/３であり、変換前後のベクトルの大きさを無視して良い場合は１でも良い。

K is √ (２) in the case of absolute conversion, / in the case of relative conversion, and may be 1 if the magnitude of the vector before and after conversion can be ignored.

  The PI control unit 110 obtains the d-axis basic voltage command value Vdref1 based on the deviation Id1 between the d-axis basic current command value Idref1 and the d-axis motor current Idm, similarly to the PI control unit 35 shown in FIG. Similarly, PI control section 120 obtains q-axis basic voltage command value Vqref1 based on deviation Iq1 between q-axis basic current command value Iqref1 and q-axis motor current Iqm.

  The two-phase / three-phase converter 140 converts a two-phase voltage including a d-axis basic voltage command value Vdref1 and a q-axis basic voltage command value Vqref1 into a three-phase voltage using the rotation angle θe. Specifically, the two-phase voltage is converted into a three-phase voltage, a U-phase basic voltage command value Vuref1, a V-phase basic voltage command value Vvref1, and a W-phase basic voltage command value Vwref1 according to Equation 4 below.

２相／３相変換部１５０は、ｄ軸補償電圧指令値Ｖｄｒｅｆ５及びｑ軸補償電圧指令値Ｖｑｒｅｆ５からなる２相の電圧を３相の電圧に変換するが、回転角θｅに加えて磁束位相α５を使用し、さらに、第５次高調波を対象としているので、それらを５倍にして使用する。具体的には、下記数５に従って、２相の電圧を３相の電圧であるＵ相補償電圧指令値Ｖｕｒｅｆ５、Ｖ相補償電圧指令値Ｖｖｒｅｆ５及びＷ相補償電圧指令値Ｖｗｒｅｆ５に変換する。

The two-phase / three-phase converter 150 converts a two-phase voltage consisting of the d-axis compensation voltage command value Vdref5 and the q-axis compensation voltage command value Vqref5 into a three-phase voltage. In addition to the rotation angle θe, the magnetic flux phase α5 , And the fifth harmonic is used. Specifically, the two-phase voltage is converted into a U-phase compensation voltage command value Vuref5, a V-phase compensation voltage command value Vvref5, and a W-phase compensation voltage command value Vwref5, which are three-phase voltages, according to Equation 5 below.

Ｕ相基本電圧指令値Ｖｕｒｅｆ１、Ｖ相基本電圧指令値Ｖｖｒｅｆ１及びＷ相基本電圧指令値Ｖｗｒｅｆ１は、それぞれ加算部２１０、２１１及び２１２にて、Ｕ相補償電圧指令値Ｖｕｒｅｆ５、Ｖ相補償電圧指令値Ｖｖｒｅｆ５及びＷ相補償電圧指令値Ｖｗｒｅｆ５を加算されることにより補償され、Ｕ相電圧指令値Ｖｕｒｅｆ、Ｖ相電圧指令値Ｖｖｒｅｆ及びＷ相電圧指令値Ｖｗｒｅｆとして出力される。

The U-phase basic voltage command value Vuref1, the V-phase basic voltage command value Vvref1, and the W-phase basic voltage command value Vwref1 are added to the U-phase compensation voltage command value Vuref5 and the V-phase compensation voltage command value by adders 210, 211 and 212, respectively. It is compensated by adding Vvref5 and W-phase compensation voltage command value Vwref5, and output as U-phase voltage command value Vuref, V-phase voltage command value Vvref, and W-phase voltage command value Vwref.

  The PWM control unit 36 and the inverter 37 have the same configuration as that shown in FIG. 2, and perform PWM driving of the motor 20 based on the U-phase voltage command value Vuref, the V-phase voltage command value Vvref, and the W-phase voltage command value Vwref. .

  An operation example of such a configuration will be described with reference to the flowcharts of FIGS.

  When the operation is started, the steering torque Th is detected by the torque sensor 10 (see FIG. 1), the vehicle speed Vel is detected by the vehicle speed sensor 12 (see FIG. 1) (or the CAN 40 (see FIG. 1) outputs), and the rotation angle θe is output. Is detected by the rotation angle sensor 21 (step S10). The steering torque Th and the vehicle speed Vel are input to a current command value calculation unit 31, and the rotation angle θe is a two-phase / 3-phase conversion unit 140, a two-phase / 3-phase conversion unit 150, a three-phase / 2-phase conversion unit 160, and a motor angular velocity. The data is input to the arithmetic unit 170. The motor current detector 38 detects the U-phase motor current Ium flowing in the U-phase, the V-phase motor current Ivm flowing in the V-phase, and the W-phase motor current Iwm flowing in the W-phase of the motor 20 (step S20). Output to phase conversion section 160.

  The current command value calculator 31 calculates the current command value Iref based on the steering torque Th and the vehicle speed Vel using an assist map having characteristics as shown in FIG. 4 (step S30), and obtains the dq-axis current command value. Output to arithmetic unit 100.

  The motor angular velocity calculator 170 calculates the motor angular velocity ωe from the rotation angle θe (step S40), and outputs the motor angular velocity ωe to the dq-axis current command value calculator 100 and the harmonic model unit 130. The operations of the current command value calculation unit 31 and the motor angular velocity calculation unit 170 may be performed in a different order or in parallel.

  The dq-axis current command value calculation unit 100 calculates a d-axis basic current command value Idref1 and a q-axis basic current command value Iqref1 using the current command value Iref and the motor angular velocity ωe (step S50). The d-axis basic current command value Idref1 and the q-axis basic current command value Iqref1 are input to the harmonic model unit 130 and added to the subtraction units 200 and 201, respectively.

  The harmonic model unit 130 performs a compensation command value calculation using the input d-axis basic current command value Idref1, q-axis basic current command value Iqref1, and motor angular velocity ωe (step S60).

  In the compensation command value calculation, first, the polar coordinate conversion unit 131 of the harmonic model unit 130 inputs the d-axis basic current command value Idref1 and the q-axis basic current command value Iqref1, and performs the current amplitude Iap and the current by polar coordinate conversion using Equation 1. The advance angle βi is calculated (step S610) and output to the magnetic flux calculation unit 132. The magnetic flux calculation unit 132 obtains a magnetic flux amplitude φ5 and a magnetic flux phase α5 corresponding to the current amplitude Iap and the current advance angle βi from a motor characteristic amount conversion table stored in advance (step S620), and the magnetic flux amplitude φ5 is a compensation command value. The magnetic flux phase α5 is output to the calculation unit 133 and the two-phase / three-phase conversion unit 150, respectively. The compensation command value calculation unit 133 receives the motor angular velocity ωe together with the magnetic flux amplitude φ5, and calculates the d-axis compensation voltage command value Vdref5 and the q-axis compensation voltage command value Vqref5 using Equation 2 (Step S630). Output to three-phase converter 150.

  The two-phase / three-phase converter 150 receives the rotation angle θe and the magnetic flux phase α5, and converts the d-axis compensation voltage command value Vdref5 and the q-axis compensation voltage command value Vqref5 into three-phase voltages using Equation (5). Step S70), and output to the adders 210, 211 and 212 as a U-phase compensation voltage command value Vuref5, a V-phase compensation voltage command value Vvref5 and a W-phase compensation voltage command value Vwref5, respectively.

  The three-phase / two-phase converter 160, which has input the U-phase motor current Ium, the V-phase motor current Ivm, and the W-phase motor current Iwm detected by the motor current detector 38 and the rotation angle θe detected by the rotation angle sensor 21, The d-axis motor current Idm and the q-axis motor current Iqm are calculated by using Equation (3) (Step S80), and the d-axis motor current Idm and the q-axis motor current Iqm are subtracted and input to the subtraction units 200 and 201, respectively.

  The subtraction unit 200 calculates a deviation Id1 between the d-axis basic current command value Idref1 and the d-axis motor current Idm, and outputs the deviation Id1 to the PI control unit 110. The subtraction unit 201 calculates a deviation Iq1 between the q-axis basic current command value Iqref1 and the q-axis motor current Iqm, and outputs it to the PI control unit 120 (step S90).

  The PI control unit 110 obtains a d-axis basic voltage command value Vdref1 from the deviation Id1, and the PI control unit 120 obtains a q-axis basic voltage command value Vqref1 from the deviation Iq1 (step S100).

  The d-axis basic voltage command value Vdref1 and the q-axis basic voltage command value Vqref1 are input to the two-phase / 3-phase conversion unit 140, and the two-phase / 3-phase conversion unit 140 uses the input rotation angle θe to obtain Equation 4 Thus, the reference voltage is converted into a U-phase basic voltage command value Vuref1, a V-phase basic voltage command value Vvref1 and a W-phase basic voltage command value Vwref1 (step S110), and output to the adders 210, 211 and 212, respectively.

  The adder 210 compensates the U-phase basic voltage command value Vuref1 by adding the U-phase compensation voltage command value Vuref5, and outputs the same as the U-phase voltage command value Vuref. Similarly, adding section 211 compensates for V-phase basic voltage command value Vvref1 by adding V-phase compensation voltage command value Vvref5, and outputs the same as V-phase voltage command value Vvref. By adding the command value Vwref5, the W-phase basic voltage command value Vwref1 is compensated and output as the W-phase voltage command value Vwref (step S120).

  The U-phase voltage command value Vuref, the V-phase voltage command value Vvref, and the W-phase voltage command value Vwref are input to the PWM control unit 36, and the motor 20 is PWM-driven via the inverter 37 (step S130).

  The operation from the output of the d-axis basic current command value Idref1 and the q-axis basic current command value Iqref1 to the calculation of the U-phase compensation voltage command value Vuref5, the V-phase compensation voltage command value Vvref5, and the W-phase compensation voltage command value Vwref5. (Steps S60 and S70) and the operations (steps S80 to S110) until the calculation of the U-phase basic voltage command value Vuref1, the V-phase basic voltage command value Vvref1, and the W-phase basic voltage command value Vwref1 are performed in parallel even if the order is reversed. May be executed.

  Another embodiment (second embodiment) of the present invention will be described.

  In the first embodiment, only the fifth harmonic is targeted, but in the present embodiment, the seventh harmonic is also targeted in addition to the fifth harmonic. By targeting a plurality of harmonics, the accuracy of the harmonic model is increased, and the torque ripple can be reduced more accurately.

  FIG. 8 shows a configuration example of the present embodiment. Compared with the configuration example of the first embodiment shown in FIG. 3, since the seventh harmonic is also targeted, a harmonic model unit 220 and a two-phase / three-phase conversion unit 230 for that purpose are added. Adders 213, 214 and 215 have been added. The same components as those in the configuration example of FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted.

  Like the harmonic model unit 130, the harmonic model unit 220 converts the d-axis basic current command value Idref1 and the q-axis basic current command value Iqref1 into a d-axis compensation voltage command, which is a compensation command value, based on the harmonic model. The value Vdref7 and the q-axis compensation voltage command value Vqref7 are calculated. However, since the harmonic model is intended for the seventh harmonic, the motor angular velocity ωe is used seven times for the calculation. The harmonic model unit 220 includes a polar coordinate converter, a magnetic flux calculator, and a compensation command value calculator, similarly to the configuration example of the harmonic model unit 130 shown in FIG. Among them, the magnetic flux calculation unit expresses the amplitude (magnetic flux amplitude) φ7 and phase (magnetic flux phase) α7 of the seventh harmonic component of the magnetic flux corresponding to the current amplitude Iap and the current advance angle βi in a numerical data series. A magnetic flux conversion table is held, and a magnetic flux amplitude φ7 and a magnetic flux phase α7 corresponding to the input current amplitude Iap and the current advance angle βi are obtained using the motor characteristic quantity conversion table. The compensation command value calculation unit calculates the d-axis compensation voltage command value Vdref7 and the q-axis compensation voltage command value Vqref7 using the magnetic flux amplitude φ7 and the motor angular velocity ωe according to the following Expression 6.

２相／３相変換部２３０は、２相／３相変換部１５０と同様に、ｄ軸補償電圧指令値Ｖｄｒｅｆ７及びｑ軸補償電圧指令値Ｖｑｒｅｆ７からなる２相の電圧を３相の電圧に変換するが、第７次高調波を対象としているので、回転角θｅ及び磁束位相α７を７倍にして使用する。具体的には、下記数７に従って、２相の電圧を３相の電圧であるＵ相補償電圧指令値Ｖｕｒｅｆ７、Ｖ相補償電圧指令値Ｖｖｒｅｆ７及びＷ相補償電圧指令値Ｖｗｒｅｆ７に変換する。

The two-phase / three-phase converter 230 converts a two-phase voltage composed of the d-axis compensation voltage command value Vdref7 and the q-axis compensation voltage command value Vqref7 into a three-phase voltage, similarly to the two-phase / 3-phase converter 150. However, since the seventh harmonic is targeted, the rotation angle θe and the magnetic flux phase α7 are used after being increased seven times. Specifically, the two-phase voltage is converted into a U-phase compensation voltage command value Vuref7, a V-phase compensation voltage command value Vvref7, and a W-phase compensation voltage command value Vwref7, which are three-phase voltages, according to the following Expression 7.

第２実施形態での動作例を図９のフローチャートを参照して説明する。

An operation example in the second embodiment will be described with reference to the flowchart in FIG.

  Compared to the operation example in the first embodiment shown in FIG. 6, the operation in the harmonic model unit 220 and the two-phase / 3-phase conversion unit 230 added to target the seventh harmonic is as follows. Steps S61 and S71 are added after steps S60 and S70, respectively. Further, the operation for compensating the basic voltage command value is different (step S121).

  In step S61, the harmonic model unit 220 performs a compensation command value calculation using the input d-axis basic current command value Idref1, q-axis basic current command value Iqref1, and motor angular velocity ωe, and obtains the obtained d-axis compensation voltage. Command value Vdref7 and q-axis compensation voltage command value Vqref7 are output to two-phase / three-phase converter 230. The operation of the harmonic model unit 220 uses Equation 6 instead of Equation 2, and except that the motor feature value conversion table is for the seventh harmonic, the harmonic model unit 130 shown in FIG. Operation is the same.

  In step S71, the two-phase / three-phase converter 230 receives the rotation angle θe and the magnetic flux phase α7, and converts the d-axis compensation voltage command value Vdref7 and the q-axis compensation voltage command value Vqref7 into a three-phase voltage using Expression 7. And outputs them to the adders 213, 214, and 215 as a U-phase compensation voltage command value Vuref7, a V-phase compensation voltage command value Vvref7, and a W-phase compensation voltage command value Vwref7, respectively.

  In step S121, the U-phase compensation voltage command value Vuref5 is added to the U-phase basic voltage command value Vuref1 output from the two-phase / 3-phase conversion unit 140 by the addition unit 210, and the U-phase compensation voltage command value is further added by the addition unit 213. Vuref7 is added and output as the U-phase voltage command value Vuref. Similarly, the addition unit 211 adds the V-phase compensation voltage command value Vvref5 to the V-phase basic voltage command value Vvref1, and the addition unit 214 adds the V-phase compensation voltage command value Vvref7, which is output as the V-phase voltage command value Vvref. The addition unit 212 adds the W-phase compensation voltage command value Vwref5 to the W-phase basic voltage command value Vwref1, and the addition unit 215 adds the W-phase compensation voltage command value Vwref7, which is output as the W-phase voltage command value Vwref. You.

  The operation related to the fifth harmonic and the operation related to the seventh harmonic may be executed in a different order or in parallel.

  Another embodiment (third embodiment) of the present invention will be described.

  In the first embodiment and the second embodiment, the motor feature amount conversion table is represented by a numerical data series, but in the present embodiment, a motor feature amount conversion table represented in a simplified form is used. I do. For example, of the current amplitude Iap and the current advance βi calculated by converting the d-axis basic current command value Idref1 and the q-axis basic current command value Iqref1 into polar coordinates, only the current amplitude Iap is used, and the magnetic flux for the current amplitude Iap is used. A change in the amplitude and the magnetic flux phase approximated by a polygonal line as shown in FIG. 10 is used as a motor feature amount conversion table. FIG. 10A is an approximation of a change in magnetic flux amplitude with respect to the current amplitude Iap by a polygonal line. The domain of the current amplitude Iap is divided at regular intervals, and in each divided section, the current amplitude Iap and the current amplitude Iap in the divided section are divided. An approximate straight line is obtained from the value of the magnetic flux amplitude by a straight line approximation by the least square method or the like, and the approximate straight lines of the respective divided sections are connected to obtain an approximate straight line. FIG. 10B approximates a change in the magnetic flux phase with respect to the current amplitude Iap, which is obtained in a similar manner, using a polygonal line. The interval at which the image is divided may not be constant. For example, the interval at which the fluctuation is assumed to be large may be reduced. Also, instead of a straight line, it may be approximated by a curve such as a quadratic function.

  The configuration and operation of the third embodiment are basically the same as those of the first and second embodiments, except that the format of the motor feature quantity conversion table held by the magnetic flux calculation unit of the harmonic model unit is different. The only difference is that the magnetic flux calculation unit inputs only the current amplitude Iap and obtains the magnetic flux amplitude and the magnetic flux phase from the motor feature quantity conversion table.

  As described above, the required memory amount can be further reduced by simplifying the motor characteristic amount conversion table.

  In the above-described embodiments (first to third embodiments), magnetic flux is used as a motor feature. However, instead of magnetic flux, an inductance or resistance may be used. May be used. Although the fifth and seventh harmonics are targeted as harmonics, harmonics of other orders may be targeted.

1 Handle 2 Column shaft (steering shaft, handle shaft)
Reference Signs List 10 Torque sensor 12 Vehicle speed sensor 13 Battery 20 Motor 21 Rotation angle sensor 30 Control unit (ECU)
31 Current command value calculation units 35, 110, 120 PI control unit 36 PWM control unit 37 Inverter 38 Motor current detector 100 dq-axis current command value calculation units 130, 220 Harmonic model unit 131 Polar coordinate conversion unit 132 Magnetic flux calculation unit 133 Compensation Command value calculation units 140, 150, 230 2-phase / 3-phase conversion unit 160 3-phase / 2-phase conversion unit 170 Motor angular velocity calculation unit

Claims (7)

A motor control device that drives and controls the motor based on a current command value for the motor,
A model in which a characteristic of at least one harmonic component of a magnetic flux of a magnetic field generated by the motor is learned, and a harmonic model unit that calculates a compensation command value from the current command value using a motor angular velocity of the motor;
The harmonic model unit calculates the compensation command value using a motor feature value conversion table that determines the value of the harmonic component of the magnetic flux corresponding to the current command value,
A motor control device that controls the drive of the motor based on the current command value and the compensation command value. A current control unit that calculates a voltage command value that controls a current supplied to the motor based on the current command value,
2. The motor control device according to claim 1, wherein the drive control of the motor is performed based on the voltage command value compensated by the compensation command value. 3.   The motor control device according to claim 2, wherein the voltage command value is compensated by adding the compensation command value. The harmonic model unit,
A polar coordinate conversion unit that converts the current command value into polar coordinates,
A magnetic flux calculation unit that obtains a harmonic component of the magnetic flux corresponding to the current command value converted into the polar coordinates by the motor feature quantity conversion table;
The motor control device according to any one of claims 1 to 3 and a compensation command value calculator for calculating the compensation command value using the harmonic component and the motor angular speed of the magnetic flux. The motor control device according to any one of claims 1 to 4 comprising at least fifth harmonic as the harmonic component. The motor control device according to any one of claims 1 to 5 , wherein the motor control device is used in an electric power steering device that assists a steering system by driving the motor. An electric power steering device comprising the motor control device according to claim 6 .

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