JP2009089524A - Motor control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor controller exhibiting excellent current response characteristics. <P>SOLUTION: The motor controller comprises a current command table 111 which outputs a target vector current indication signal indicating target vector currents id* and iq* for generating an indicated torque, a gain-scheduling H∞ current controller 113 designed as gain-scheduling H∞ problem by using the angular speed ω of a motor 21 as a variation parameter and outputting the target vector current indication signal while correcting, a driver circuit 12 for driving the motor 21 based on corrected target vector current indication signals vd and vq, and a rotation sensor 14 for feeding the angular speed ω of the motor 21 back to the gain-scheduling H∞ current controller 113. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a motor control system, and more particularly to a motor control system that performs vector control of a motor.

Vector control that can be controlled to a current according to the torque of the motor is known (for example, see Non-Patent Document 1).
The basic principle of an AC motor is to drive a motor by passing a sinusoidal current through a three-phase coil, and vector control is common (see, for example, Non-Patent Document 1, page 80).
In the conventional vector control, the vector current is controlled by PID control.

The inductances Ld and Lq, the resistance value R, and the angular velocity ω of the motor coil vary depending on operating conditions. For this reason, the current response of the motor has nonlinearity. Therefore, in the conventional simple PID control, the current response is not stable due to the influence of nonlinearity.
Hidehiko Sugimoto, “Theory and Design of AC Servo Systems,” Electronic Publishing Company, page 80

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a drive system that can stabilize a current response.

In order to achieve the above object, the motor control system of the present invention provides:
A target vector current instruction signal output means for receiving a torque instruction signal instructing a torque to be generated by the motor and outputting a target vector current instruction signal instructing a vector current for generating the torque;
An H∞ controller that is designed as a gain schedule H∞ problem using the angular velocity of the motor to be controlled as a variation parameter, and corrects the target vector current supplied from the target vector current indicating means;
Driver means for driving the motor to be controlled based on the corrected target vector current instruction signal from the H∞ controller;
Monitoring means for monitoring the control target motor driven by the driver means, and notifying the angular velocity of the motor to the H∞ controller;
It is characterized by providing.

  The H∞ controller, for example, handles parameter fluctuations due to fluctuations in at least one of the inductance and resistance value of the motor in a generalized plant for H∞ control, and uses the angular velocity as an observation parameter, and is robust to these parameter fluctuations. It is designed as follows.

  The H∞ controller may handle parameter variations due to variations in motor inductance and resistance in a generalized plant for H∞ control.

  The H∞ controller, for example, for a parameter group including at least one of parameters of perturbation, target value followability, and disturbance suppression in addition to parameter fluctuation due to fluctuation of at least one of motor inductance and resistance value. And may be designed to be robust and stable.

  According to the above configuration, a motor control system with excellent current response can be obtained.

(First embodiment)
The motor control system 1000 according to the first embodiment of the present invention will be described below.
As shown in FIG. 1, a motor control system 1000 according to the present embodiment controls a motor 21, and includes an electronic control unit (ECU) 11, a driver circuit 12, a current sensor 13, and the like. And a position sensor (rotation sensor) 14.

  The ECU 11 is composed of a microprocessor unit and the like, and supplies drive control signals vd and vq for controlling on / off of each of the three phases to the driver circuit 12 so as to obtain a target torque Tt instructed from the outside. To do. The ECU 11 functionally includes a current command table 111, a subtractor 112, and a gain schedule H∞ current controller 113.

  As shown in FIG. 2, the current command table 111 is based on the characteristics of the motor 21 to be controlled, and the rotational speed and torque, and the target value Id * of the vector current necessary to obtain the torque at the rotational speed. Iq * is stored in association with each other.

  The subtractor 112 subtracts the measured values of the vector currents id and iq supplied to the motor 21 from the target values Id * and Iq * of the vector current read from the current command table 111 to obtain a vector current deviation (id * -Id) and (iq * -iq) are output.

  The gain schedule H∞ current controller 113 is a controller derived by incorporating fluctuations in the inductance L and resistance R of the motor 21 into the generalized plant and derived as an H∞ control problem, and the current response is stabilized regardless of these fluctuations. In this manner, the vector current target values Id * and Iq * read from the current command table 111 are corrected, and the corrected target vector current instruction signals vd and vq are output. Specifically, the gain schedule H∞ current controller 113 uses the gain schedule H as a variation parameter that can observe the deviations (id * −id) and (iq * −iq) of the vector current and the angular velocity ω of the motor 21. By performing the ∞ control, the vector current instruction values vd and vq are output. The driver circuit 12 drives the motor 21 in accordance with the instruction values vd and vq, thereby enabling a stable current response to fluctuations in the angular velocity ω of the motor 21.

The gain schedule H∞ current controller 113 is functionally composed of an H∞ controller 115 and a Δω controller 116 that adjusts and feeds back the output of the H∞ controller 115 based on the angular velocity ω.
Details of the gain schedule H∞ current controller 113 will be described later.

  The driver circuit 12 supplies U, V, and W three-phase currents to the motor 21 in accordance with vector current indication values vd and vq from the ECU 11, and includes a two-phase / three-phase converter 121 and a PWM modulator 122. And an inverter circuit 123.

  The two-phase / three-phase converter 121 receives the two-phase vector current instruction values vd and vq from the gain schedule H∞ current controller 113 according to the rotor position notified from the rotation sensor 14. Convert to values Iu, Iv, Iw and output.

  The pulse width modulator (Pulse Width Modulation modulator) 122 performs pulse width modulation on the three-phase current indication values Iu, Iv, and Iw supplied from the two-phase / three-phase converter 121, and corresponds to the designated current value. The pulse signals Pu, Pv and Pw having the pulse width to be output are output.

  The inverter circuit 123 is composed of a three-phase bullbridge circuit or the like, and is turned on / off according to the pulse signals Pu, Pv, Pw, and supplies motor driving currents iu, iv, iw to the motor 21.

  The current sensor 13 measures the U, V, and W three-phase currents of the motor 21 and supplies a current signal corresponding to the measured current value to the ECU 11. The current sensor 13 and the three-phase / two-phase converter Circuit 132.

  The current calculation circuit 131 detects two phases of the current flowing through the motor 21 and obtains and outputs a current value of each of the three phases.

  The three-phase / two-phase conversion circuit 132 converts the three-phase current value supplied from the current calculation circuit 131 into two-phase vector currents id and iq according to the position of the rotor notified from the rotation sensor 14. , Supplied to the subtractor 112 of the ECU 11.

  The rotation sensor 14 is a circuit that detects the position of the rotor of the motor 21 and supplies a position signal to the driver circuit 12 and a position signal and an angular velocity signal to the ECU 11. The rotation sensor 14 includes a resolver 141 and a rotation speed calculation circuit 142. .

  The resolver 141 detects the rotational position of the rotor of the motor 21 with high accuracy, and outputs a position signal indicating the position of the rotor of the motor 21 to the two-phase / three-phase converter 121, the three-phase / two-phase converter 132, and the rotational speed calculation. Supply to circuit 142.

  The rotational speed calculation circuit 142 obtains the rotational speed and angular velocity ω of the rotor of the motor 21 on the basis of the position signal output from the resolver 141, determines the rotational speed in the current command table, and sets the angular speed ω in the gain schedule H∞ current controller. 113.

ｖｄ：ドライバ回路を含むモータのｄ軸方向の入力電流ベクトル、ｖｑ：ドライバ回路を含むモータのｑ軸方向の入力電流ベクトル、ｉｄ：モータのｄ軸方向の電流ベクトル、ｉｑ：モータのｑ軸方向の電流ベクトル、Ｒ：モータ２１のコイル抵抗、Ｌｄ：ｄ軸インダクタンス、Ｌｑ：ｑ軸インダクタンス、ω：モータ角速度、Ψａ：公差磁束、ｐ：比例定数 Next, details of the gain schedule H∞ current controller 113 will be described.
A general current equation of the motor is shown in Formula 1.

vd: input current vector in the d-axis direction of the motor including the driver circuit, vq: input current vector in the q-axis direction of the motor including the driver circuit, id: current vector in the d-axis direction of the motor, iq: q-axis direction of the motor Current vector, R: coil resistance of motor 21, Ld: d-axis inductance, Lq: q-axis inductance, ω: motor angular velocity, Ψa: tolerance magnetic flux, p: proportional constant

  Inductances Ld and Lq, DC resistance R, and each speed ω shown in Formula 1 vary depending on operating conditions. For this reason, the current response shown as the output current with respect to the input current has nonlinearity. For this reason, in simple PID (Proportional Integral Derivative) control according to id and iq, the current response is not stable due to nonlinear influence.

  That is, as shown in FIG. 3, the control object 31 including the driver circuit 12, the motor 21, and the current sensor 13 is generalized by feeding back the variation ΔL of the inductance L, the variation ΔR of the resistance, and the variation Δω of the angular velocity. It can be represented by a plant.

  In order to stabilize the current response of the control object 31, the observation parameter, the angular velocity ω, is used as a gain schedule parameter, and the H∞ control is performed so as to ensure robustness against parameter variations of the coil inductances Ld and Lq and the coil resistance R. It is assumed that a problem is satisfied and conditions that satisfy these conditions are obtained.

Ｌｄ（ΔＬｄ）：変化を反映したインダクタンスＬｄ、
Ｌｑ（ΔＬｑ）：変化を反映したインダクタンスＬｑ、
Ｒ（ΔＲ）：変化を反映した抵抗Ｒ、
ω（θ）：ロータの回転数θにおける角速度、任意の範囲の値、例えば、−５０００〜＋５０００の範囲の値である。 First, when Equation 1 is rewritten using the normalized variation Δ (−1 <Δ <1) and the normalized rotation speed θ (−1 <θ <1), as shown in Equation 2. Become.

Ld (ΔLd): inductance Ld reflecting the change,
Lq (ΔLq): inductance Lq reflecting the change,
R (ΔR): resistance R reflecting the change,
ω (θ): angular velocity at the rotational speed θ of the rotor, a value in an arbitrary range, for example, a value in a range of −5000 to +5000.

Each parameter is shown in a block diagram as shown in FIGS.
As shown in FIG. 4A, the inductance Ld (ΔLd) indicates that the current input is output by PI control (Ldp) and the change ΔLd of Ld is reflected in the next control.
As shown in FIG. 4B, the inductance Lq (ΔLq) indicates that the current input is output by the PI control (Lqp) and the change ΔLq of Lq is reflected in the next control.
As shown in FIG. 4C, the resistance R (ΔR) indicates that the current input is output by PI control (Rp) and the change ΔR in R is reflected in the next control.
As shown in FIG. 4D, the angular velocity ω (θ) represents that the current input is output by the PI control (ωp) and the rotational speed θ is reflected in the next control.

  Using the respective blocks shown in FIGS. 4A to 4D, Expression 2 is expressed in a block diagram as shown in FIG.

  When the dotted line portion of FIG. 5 is combined into one current model block, motor perturbations Δpr and Δpy are added, and further, the target value tracking signal line w1 and the harmonic disturbance w2 are added, and the entire control system is rewritten. The block diagram shown in FIG. 6 is obtained. The signal line represents a d-axis and q-axis vector.

  The reference model is an ideal current model, which outputs an ideal system control output for a two-phase target current value.

  From FIG. 6, it can be seen that this H∞ control problem is equivalent to the gain schedule problem of FIG.

That is, it is stable for all rotation speeds θ, and the H∞ norm from W to Z is
|| TZW || ∞ <γ
By obtaining the gain schedule H∞ current controller 113 that satisfies the above, the performance incorporated in the generalized plant described above, that is, robust stability against fluctuations of inductances Ld and Lq, fluctuations of resistance R, fluctuations of angular velocity ω, and perturbations Performance, target value followability, and disturbance suppression performance can be satisfied at the same time.

Therefore,
|| S · F _l (H, K) · S ⁻¹ || ∞ <γ
What is necessary is just to obtain | require K and S which satisfy | fill using algorithms, such as dual iteration, and to mount in the gain schedule H∞ current controller 113.

As shown in FIG. 8, the gain schedule H∞ current controller 113 obtained in this way receives the input at the timing t = k of the H∞ controller 115 as a vector u _{t = k} = [u1, u2, u3, u4], and an output at timing t = k is a vector y = [y1, y2, y3, y4], the input / output characteristics represented by Equation 3 are obtained.

  Further, the input at the timing t = k of the Δω controller 116 is a vector [y1, y2], and the output at the timing t = k is a vector [u1, u2]. The relationship between the two is expressed by a mathematical formula based on the angular velocity ω.

  The current response characteristics of the gain schedule H∞ current controller 113 designed in this way are shown in FIG. 9 in comparison with the current response specification by the conventional PID control controller.

FIGS. 9A and 9B show the step responses of the vector currents id and iq when ω, R, Ld, and Lq are varied over the entire range of the motor by conventional normal PI control.
9 (c) and 9 (d) are derived as the H∞ control problem described above, and the gain schedule H∞ current controller 113 having the input / output characteristics described above is used to calculate ω, R, Ld, and Lq. The step responses of the vector currents id and iq when the motor is varied over the entire area are shown.
From the comparison between FIGS. 9A and 9C and the comparison between FIGS. 9B and 9D, the vector currents id and iq converge at high speed by using the gain schedule H∞ current controller 113. Thus, the effect of the current controller according to the present embodiment was confirmed.

Next, the operation of the motor control system having the above configuration will be described.
First, the target torque Tt of the motor 21 is set based on the control of the access pedal by the driver and supplied to the current command table 111.
The current command table 111 searches the table based on the instructed target torque Tt and the rotation speed of the motor 21 supplied from the rotation speed calculation circuit 142, and obtains the target torque Tt at the current rotation speed. The necessary target value id * of the d-axis vector current and the target value iq * of the q-axis vector current are supplied to the subtractor 112.

  The subtractor 112 subtracts the measured values of the vector currents id and iq supplied from the current sensor 13 from the target values Id * and Iq * of the vector current supplied from the current command table 111, and the vector current deviation (id * -Id) and (iq * -iq) (corresponding to u3 and u4 in FIG. 8) are supplied to the gain schedule H∞ current controller 113.

  The gain schedule H∞ current controller 113 includes the angular velocity ω of the rotor of the motor 21 supplied from the rotation speed calculation circuit 142, the deviation (id * −id) of the vector current supplied from the subtractor 112, and (iq * −). iq), the vector current indication value for simultaneously satisfying the fluctuation of the inductance of the motor 21, the fluctuation of the resistance R, the fluctuation of the angular velocity ω, the robust stability against perturbation, the target value follow-up performance, and the disturbance suppression performance. vd and vq (corresponding to y3 and y4 in FIG. 8) are supplied to the two-phase / three-phase converter 121 of the driver circuit 12.

  The two-phase / three-phase converter 121 receives the two-phase vector current instruction values vd and vq from the gain schedule H∞ current controller 113 according to the rotor position notified from the resolver 141. Iu, Iv, and Iw are generated and supplied to the pulse width modulator 122.

  The PWM modulator 122 performs pulse width modulation on the three-phase current instruction values Iu, Iv, and Iw supplied from the two-phase / three-phase converter 121, and a pulse signal Pu having a pulse width corresponding to the instructed current value. , Pv, Pw are supplied to the inverter circuit 123.

  The inverter circuit 123 supplies motor drive currents iu, iv, iw to the motor 21 in accordance with the pulse signals Pu, Pv, Pw.

As a result, motor drive currents iu, iv, and iw are supplied to the three-phase windings of the motor 21, and the motor 21 rotates.
The motor drive currents iu, iv, iw are output from the gain schedule H∞ current controller 113 by the inductance Ld, Lq, resistance R, angular velocity ω, and robust stability against perturbation, target value follow-up, The motor 21 is set to satisfy the disturbance suppressing performance at the same time, so that the motor 21 can be driven stably and can be driven with high follow-up performance against fluctuations in the target torque Tt.

  The motor drive currents iu, iv, iw are detected by the current calculation unit 131, converted into vector currents id, iq by the three-phase / two-phase conversion circuit 131, and fed back to the subtractor 112.

  Further, the position of the rotor of the motor 21 is detected by a resolver 141 and supplied to the two-phase / three-phase converter 121 and the three-phase / two-phase converter 132, respectively, and used for conversion. Further, the detected rotor position is supplied to the rotation speed calculation circuit 142, the rotation speed is obtained and supplied to the current command table 111, and the angular velocity ω of the rotor is obtained and supplied to the Δω controller 116, The gain schedule H∞ current controller 113 is used for the control operation.

  By continuing the above operations, stable current characteristics are exhibited regardless of fluctuations in the inductances Ld and Lq of the motor 21, fluctuations in the resistance R, fluctuations in the angular velocity ω, and perturbations. Motor control with excellent suppression is possible.

In addition, this invention is not limited to the said embodiment, A various application is possible.
For example, in the embodiment shown in FIG. 1, the deviation (id * -id) and (iq * -iq) between the target vector current and the measured vector current are input to the gain schedule H∞ current controller 113. As illustrated in (a) to (c), other input forms are possible.

In FIG. 10A, the H∞ controller 115b calculates the differences (id * −id) and (iq * −iq) between the target value of the vector current and the measured value of the vector current, and the measured values id and iq of the vector current. 6 signals including them are input.
In FIG. 10 (b), the H∞ controller 115b receives six signals including target values id * and iq * of vector current and measured values id and iq of vector current.
In FIG. 10C, the H∞ controller 115c determines the difference (id * −id), (iq * −iq) between the target value of the vector current and the measured value of the vector current, and the target value id of the vector current. Six signals including * and iq * are input.

  In any case, by using the angular velocity ω as a gain schedule parameter and deriving the controller as an H∞ control problem based on each input and output, fluctuations in the inductances Ld and Lq of the motor 21, fluctuations in the resistance R, and angular velocity ω Stable current characteristics are exhibited regardless of fluctuations and perturbations, and furthermore, motor control with excellent target value followability and excellent disturbance suppression is possible.

  Further, in the embodiment, perturbations Δpr, Δpy, target value follow-up property, disturbance suppression property, and the like are added to the controller design parameters. However, it is possible to exclude them from the design parameters. Further, the controller may be designed by adding other parameters.

  In addition, the configuration and type of the motor to be controlled, the configuration and operation of the peripheral circuit of the controller, and the like can be changed and applied as appropriate.

1 is a configuration diagram of a motor control system according to an embodiment of the present invention. It is a figure which shows the structure of the electric current command table of FIG. It is a figure which shows the structure of the control system which considered the fluctuation | variation. (A)-(d) is a block diagram showing each parameter in Numerical formula 2 in function. It is a figure showing the control system shown in FIG. 3 using the block diagram shown in FIG. FIG. 6 is a diagram illustrating FIG. 5 in an organized manner. It is a figure which shows the basic form of the control system shown in FIG. It is a figure which shows the relationship between the input and output of a current controller. It is a figure which shows the difference of the current response by the conventional PI operation | movement and the current controller which concerns on embodiment, (a) and (b) are the step response characteristics in the conventional PI operation | movement, (c) and (d) are implementation. FIG. 4A is a step response characteristic of the current controller according to the embodiment, FIG. 3A shows a step response characteristic of the d-axis vector current, and FIG. 2B and FIG. 3D show a step response characteristic of the q-axis vector current. (A)-(c) is a figure which shows the modification of a current controller, and shows the several input form of input especially.

Explanation of symbols

11 ECU (Electronic Control Unit)
12 Driver circuit (driver means)
13 Current sensor 14 Rotation sensor (monitoring means)
21 Motor 111 to be controlled Current command table (target vector current instruction signal output means)
112 Subtractor 113 Gain schedule H∞ current controller (H∞ current control means)
115 H∞ controller 116 Δω controller

Claims (4)

A target vector current instruction signal output means for receiving a torque instruction signal indicating a torque to be generated by the motor and outputting a target vector current instruction signal indicating a vector current for generating the torque;
An H∞ controller that is designed as a gain schedule H∞ problem using the angular velocity of the motor to be controlled as a variation parameter, and corrects the target vector current supplied from the target vector current indicating means;
Driver means for driving the motor to be controlled based on the corrected target vector current instruction signal from the H∞ controller;
Monitoring means for monitoring the motor to be controlled driven by the driver means, and notifying the angular velocity of the motor to the H∞ controller;
A motor control system comprising:   The H∞ controller handles parameter fluctuations due to fluctuations in at least one of the inductance and resistance of the motor in a generalized plant of H∞ control, and uses the angular velocity as an observation parameter so as to be robust and stable against these parameter fluctuations. The motor control system according to claim 1, wherein the motor control system is designed.   The H∞ controller is designed to handle parameter fluctuations due to fluctuations in motor inductance and resistance in a generalized plant for H∞ control, and to be robust and stable against these parameter fluctuations. The motor control system according to claim 1.   The H∞ controller has a parameter group including at least one of parameters of perturbation, target value followability, disturbance suppression, in addition to parameter variation due to variation of at least one of the inductance and resistance value of the motor. The motor control system according to claim 2, wherein the motor control system is designed to be robust and stable.

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