JP2008199704A - Controller and control method of electric motor, and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce fluctuation of current generated due to the component of harmonics contained in an inductive voltage generated in a coil of an electric motor. <P>SOLUTION: A disturbance observer 115 estimates induced voltages E<SB>U</SB>, E<SB>V</SB>, E<SB>W</SB>on the basis of a rotation position θ detected by a rotation position detecting section 110, coil current values i<SB>U</SB>, i<SB>V</SB>, i<SB>W</SB>detected by a three-phase current detecting section 112, voltage operation amounts v<SB>U</SB>, v<SB>V</SB>, v<SB>W</SB>detected by a three-phase voltage detecting section 113, and inductance matrix L searched by an inductance searching section 1152. The variation of the coil currents i<SB>U</SB>, i<SB>V</SB>, i<SB>W</SB>flowing through the coil of the three-phase AC electric motor 50 are reduced by subtracting correction voltages KE<SB>U</SB>, KE<SB>V</SB>, KE<SB>W</SB>obtained on the basis of the estimated induced voltages E<SB>U</SB>, E<SB>V</SB>, E<SB>W</SB>from indicated voltages rv<SB>U</SB>, rv<SB>V</SB>, rv<SB>W</SB>. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a motor control device, a control method, and a computer program.

When driving an electric motor, it is desirable to more strictly control the current flowing through the coil of the electric motor to prevent the occurrence of vibration, noise, and the like. In view of this fact, for example, Non-Patent Document 1 discloses that the current flowing through the reference axis (d-axis) and the axis (q-axis) perpendicular to the reference axis (d-axis) is independently adjusted with reference to the magnetic flux direction of the motor. So-called vector control for controlling torque is described.
“Theory and Design of AC Servo System Theory From Basics to Software Servo” Editor: Doctor of Engineering Hidehiko Sugimoto, Publishing: General Electronic Publishing Company, Chapter 4, Brushless DC Servo Motor 85-92

  In the vector control disclosed in Non-Patent Document 1, the three-phase alternating current detected by the current detector is converted into a two-phase dq coordinate system, and feedback is applied to the q-axis current and the d-axis current. Yes. For this reason, compared with the case where only the q-axis current is controlled, strict control of the magnetic flux and the torque is possible.

  When the motor is driven, an induced voltage is generated according to Faraday's law. At this time, the induced voltage contains harmonics, but the driving method of the electric motor disclosed in Non-Patent Document 1 is not designed and controlled in consideration of the harmonics contained in the induced voltage. Therefore, because of the harmonic voltage, the current flowing through the coil of the motor is deviated from the sine wave, causing fluctuation, and as a result, the motor may generate vibration and noise.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a motor control device and control method capable of suppressing current fluctuation.
Another object of the present invention is to provide a control device and a control method for an electric motor that generates less vibration and noise.

In order to achieve the above object, an electric motor control device according to a first aspect of the present invention includes:
Induced voltage estimating means for estimating the induced voltage generated in the coil of the motor;
Correction means for correcting and outputting an instruction signal indicating a drive voltage for driving the electric motor based on the induced voltage estimated by the induced voltage estimation means;
It is characterized by providing.

  For example, the correcting unit corrects the driving voltage based on the induced voltage estimated by the induced voltage estimating unit so that the current flowing through the coil of the electric motor becomes a sine wave.

For example, the induced voltage estimation means includes:
Current detection means for detecting the current value of the current flowing in the coil of the motor;
An inductance discriminating means for discriminating the inductance of the coil of the electric motor;
Means for estimating the induced voltage of the coil of the motor based on the current value detected by the current detection means and the inductance determined by the inductance determination means;
Is provided.

  For example, the induced voltage estimation means includes: a current detection means for detecting a current value of a current flowing in a coil of the motor; a voltage operation amount detection means for detecting an operation amount of a voltage applied to the coil of the motor; Based on the inductance determination means for obtaining the inductance, the current value detected by the current detection means, the operation amount of the applied voltage detected by the voltage operation amount detection means, and the inductance determined by the inductance determination means And a means for estimating an induced voltage of the electric motor.

  For example, the induced voltage estimation means includes a table that stores the inductance of the coil in association with the rotational position of the rotor of the electric motor and the current value of the current flowing through the coil, and a rotational position detection means that detects the rotational position of the rotor; Based on the current detection means for detecting the current value of the current flowing through the coil of the motor, the rotational position detected by the rotational position detection means, and the current value detected by the current detection means, the table is searched. Inductance determination means for obtaining the inductance of the coil; the current value detected by the current detection means; the operation amount of the applied voltage detected by the voltage operation amount detection means; and the inductance determined by the inductance determination means And means for estimating the induced voltage of the electric motor based on the above.

  Multiplication means for multiplying the value estimated by the induced voltage estimation means is arranged, and the correction means is configured to correct an instruction voltage for controlling the electric motor based on a value multiplied by the multiplication means. May be.

  A drive unit that drives and controls the electric motor with a drive voltage indicated by the drive voltage instruction signal corrected by the correction unit may be arranged.

In order to achieve the above object, an electric motor control device according to a second aspect of the present invention includes:
An instruction signal generating means for generating an instruction signal for instructing a driving voltage of the electric motor;
Drive current detection means for detecting the current flowing in the coil of the electric motor;
Correction means for correcting the instruction value generated by the instruction signal generation means so that the waveform of the drive current detected by the drive current detection means approaches a sine wave;
It is characterized by providing.

In order to achieve the above object, an electric motor control method according to a third aspect of the present invention includes:
An induced voltage estimation step for estimating the induced voltage generated in the coil of the motor;
A correction step of correcting and outputting an instruction signal of a drive voltage for driving the electric motor based on the estimated induced voltage;
It is characterized by providing.

  It is also possible to manufacture, distribute, etc. a computer program that causes the computer to function as the above-described control device or that causes the computer to execute the above-described processing.

  According to the present invention, the instruction voltage is corrected. For this reason, current fluctuations and fluctuations can be reduced.

  Hereinafter, with reference to drawings, the control device of the electric motor concerning the embodiment of the present invention and the control method which this control device performs are explained.

  As shown in FIG. 1, the motor control device 100 according to the present embodiment is a device for driving and controlling a three-phase AC motor 50, and includes a torque / current conversion unit 101, subtracters 102 and 103, and a current. Control unit 104, two-phase / three-phase voltage conversion unit 105, subtractors 106, 107, 108, PWM generation unit 109, rotation position detection unit 110, rotation number detection unit 111, and three-phase current detection unit 112, a three-phase voltage detector 113, a three-phase / two-phase current converter 114, a disturbance observer 115, and a multiplier 116. Further, an ECU (Electric Control Unit) 10 is connected to the torque / current conversion unit 101. Further, an inverter 40 is connected to the PWM generator 109. A DC power supply 20 and a capacitor 30 are connected to the inverter 40 in parallel. The inverter 40 is connected to a three-phase AC motor 50 that is a control target.

  The ECU 10 outputs to the torque / current conversion unit 101 a command torque Treq that instructs the rotational torque of the three-phase AC motor 50.

  The DC power supply 20 is connected to the inverter 40 and supplies power to the inverter 40.

  The capacitor 30 is connected to the inverter 40 in parallel with the DC power supply 20. Therefore, it has a function of charging / discharging the charge supplied to the inverter 40.

The inverter 40 drives the three-phase AC motor 50 by passing the coil currents i _U , i _V , i _W according to the PWM signal input from the PWM generator 109. Below, the function of the inverter 40 is demonstrated using FIG.

  FIG. 2 is a diagram for explaining the function of the inverter 40.

  The inverter 40 includes IGBTs 411 to 416 that are IGBTs (Insulated Gate Bipolar Transistors) and D421 to D426 that are diodes. The IGBTs 411 to 416 are supplied with a voltage from the DC power supply 20 via the capacitor 30, and each phase coil of a U-phase coil, a V-phase coil, and a W-phase coil of a three-phase AC electric motor according to a PWM waveform input from the PWM generator 109. Current is passed through. D421 to D426 are connected between the emitters and collectors of the IGBTs 411 to 416, respectively, and flow current from the emitter side to the collector side.

The three-phase AC motor 50 is a three-phase AC motor including a U-phase coil, a V-phase coil, and a W-phase coil as a stator coil. Coil currents i _U , i _V , and i _W flow through the U-phase coil, the V-phase coil, and the W-phase coil, respectively.

  The torque / current conversion unit 101 receives the instruction torque Treq from the external device 10 and the angular velocity ω from the rotation speed detection unit 111 described later. Further, current commands req_id and req_iq necessary for outputting the torque instructed by the instruction torque Treq are generated. Further, the torque / current conversion unit 101 outputs the generated current command req_id to the subtractor 102 and the current control unit 104, and outputs the generated current command req_iq to the subtractor 103 and the current control unit 104.

  The subtractor 102 obtains a current deviation ed between the current command req_id input from the torque / current conversion unit 101 and the two-phase current value id input from the three-phase / two-phase current conversion unit 114, and controls the current deviation ed as a current control. Output to the unit 104. Similarly, the subtractor 103 obtains a current deviation eq between a current command req_iq input from the torque / current conversion unit 101 and a two-phase current value iq input from a three-phase / two-phase current conversion unit 114 to be described later. Deviation eq is output to current controller 104.

  The current control unit 104 receives current commands req_id and req_iq from the torque / current conversion unit 101. Further, the current control unit 104 receives the current deviation ed from the subtracter 102 and the current deviation eq from the subtractor 103. Then, the current control unit 104 calculates instruction voltages vd and vq from the current commands req_id, req_iq, and current deviations ed and eq, and outputs the calculated instruction voltages vd and vq to a two-phase / three-phase voltage conversion unit 105 described later. To do.

The two-phase / three-phase voltage conversion unit 105 receives the instruction voltages vd and vq from the current control unit 104 and the rotation position θ from the rotation position detection unit 110 described later. Further, the two-phase / three-phase voltage conversion unit 105 calculates the instruction voltages rv _U , rv _V , rv _W from the instruction voltages vd, vq using the rotational position θ, and calculates the calculated instruction voltages rv _U , rv _V , rv. _W is output to subtractors 106, 107, and 108, which will be described later.

The subtractors 106, 107, and 108 receive the instruction voltages rv _U , rv _V , and rv _W from the two-phase / three-phase voltage conversion unit 105, respectively, and the correction voltages KE _U , KE _V , and KE _W from the multiplication unit 116 described later. Enter each. Subtracter 106, 107 and 108 can direct voltage _{rv U,} rv V, calculated rv _W from the correction voltage _{KE U, KE V, KE W} subtracted respectively voltage manipulated variable _{v U,} v V, and _{v W.} The subtractors 106, 107, 108 output the calculated voltage operation amounts v _U , v _V , v _W to a PWM generation unit 109 described later and a three-phase voltage detection unit 113 described later.

PWM generator 109, subtractor voltage manipulated variable from _{106,107,108 v U, v V, v} W enter the input to the voltage manipulated variable _{v U,} v V, inverter 40 PWM waveform according to _{v W} Output to.

  The rotational position detection unit 110 detects the rotational position θ of the rotor of the three-phase AC motor 50, and the detected rotational position θ is converted into a two-phase / three-phase voltage conversion unit 105, a rotational speed detection unit 111 described later, and a three-phase described later. / The output to the two-phase current conversion unit 114 and the inductance search unit 1152 described later. Note that the rotational position θ represents an electrical angle. A resolver or an encoder can be used for the rotational position detector 110.

  The rotation speed detection unit 111 calculates the angular velocity ω from the rotation position θ detected by the rotation position detection unit 110 and outputs the calculated angular velocity ω to the torque / current conversion unit 101. The angular velocity ω is calculated, for example, by sampling the rotational position θ at regular intervals and calculating the average value of the amount of change in the rotational position θ per sampling period.

The three-phase current detection unit 112 detects three-phase coil currents i _U , i _V , i _W flowing in the respective phase coils of the three-phase AC motor 50, and the detected values of the coil currents i _U , i _V , i _W Are output to a three-phase / two-phase current conversion unit 114 described later, an inductance search unit 1152 described later, and an induced voltage estimation unit 1153 described later.

The three-phase voltage detection unit 113 detects the voltage operation amounts v _U , v _V , and v _W output from the subtractors 106, 107, and 108, and the detected voltage operation amounts v _U , v _V , and v _W are described later. To the induced voltage estimation unit 1153.

The three-phase / two-phase current converter 114 uses the values of the three-phase coil currents i _U , i _V , i _W detected by the three-phase current detector 112 and the rotational position θ detected by the rotational position detector 110. To two-phase current values id and iq. In addition, the three-phase / two-phase current conversion unit 114 outputs the converted two-phase current values id and iq to the subtracters 102 and 103, respectively.

The disturbance observer 115 is a device that estimates the induced voltages E _U , E _V , and E _W as a kind of disturbance. Specifically, the rotational position θ detected by the rotational position detector 110, the three-phase coil currents i _U , i _V , i _W detected by the three-phase current detector 112, and the three-phase voltage detector 113. The induced voltages E _U , E _V , E _W are estimated on the basis of the voltage manipulated variables v _U , v _V , v _W detected by, and the inductance matrix L searched by the inductance search unit 1152 described later.

  The disturbance observer 115 includes a table storage unit 1151, an inductance search unit 1152, and an induced voltage estimation unit 1153.

The table storage unit 1151 stores a three-dimensional table tbl obtained by previously measuring the relationship between the coil currents i _U , i _V , i _W and the self-inductance and the mutual inductance with respect to the rotational position θ through experiments or the like.

The configuration of the three-dimensional table tbl will be described in more detail.
FIG. 3A shows the relationship between the rotational position θ of the rotor of the three-phase AC motor 50 and the self-inductance L _U (H) of the U-phase coil when the U-phase coil current i _U has a specific value. Indicates. The vertical axis represents the U-phase self-inductance L _U (H), and the horizontal axis represents the rotational position θ (degrees). As shown in FIG. 3A, the U-phase self-inductance L _U (H) varies depending on the rotational position θ (degrees). The U-phase self-inductance L _U (H) varies depending on the magnitude of the coil current i _U (A) even if the rotational position θ (degrees) is the same.

FIG. 3B is a diagram showing the relationship among the rotational position, the coil current, and the mutual inductance. In FIG. 3B, the vertical direction represents the mutual inductance M _UV (H) between the U phase and the V phase, and the horizontal direction represents the rotational position θ (degrees). As shown in FIG. 3B, the mutual inductance M _UV (H) between the U phase and the V phase varies depending on the rotational position θ (degrees). Further, the mutual inductance M _UV (H) between the U phase and the V phase varies depending on the magnitude of the coil current i _U (A) even if the rotational position θ (degree) is the same.

In the table storage unit 1151, the three-phase self-inductances L _U , L _V , L _W and the mutual inductances M _UV , M _UW , M between the three phases obtained by analyzing the operating characteristics of the three-phase AC motor 50 in advance. _{For all of VU} , M _VW , M _WU , and M _WV , a three-dimensional table tbl for the rotational position θ and coil currents i _U , i _V , and i _W is stored. Therefore, by referring to the table tlb from the rotational position θ detected in the rotational position detection and the coil currents i _U , i _V , i _W detected in the three-phase current detection, the UVW phase self Inductance and mutual inductance can be determined (expected).

The inductance search unit 1152 searches the three-dimensional table tbl from the rotational position θ and the values of the coil currents i _U , i _V , i _W to obtain the self-inductance and mutual inductance of the UVW phase, and obtains an inductance matrix L described later. Ask. The inductance search unit 1152 outputs the obtained inductance matrix L to the induced voltage estimation unit 1153.

The induced voltage estimation unit 1153 estimates the induced voltages E _U , E _V , E _W from the coil currents i _U , i _V , i _W , the voltage manipulated variables v _U , v _V , v _W, and the inductance matrix L. To do. In addition, the induced voltage estimation unit 1153 outputs the estimated induced voltages E _U , E _V , and E _W to the multiplication unit 116 described later.

The multiplier 116 receives the induced voltages E _U , E _V , E _W obtained by the induced voltage estimation unit 1153, multiplies the induced voltages E _U , E _V , E _W and the proportional gain K, respectively, and corrects the corrected voltages KE _U , KE _V and KE _W are obtained. Further, the multiplication unit 116 outputs the obtained correction voltages KE _U , KE _V , and KE _W to the subtracters 106, 107, and 108.

  Next, the operation of the motor control device 100 having the above configuration will be described.

  First, the ECU 10 outputs an instruction torque Treq indicating the target value of the rotational torque of the three-phase AC motor 50 to the torque / current conversion unit 101 as needed for control.

  The rotational position detector 110 detects the rotational position θ of the rotor of the three-phase AC motor 50.

  The rotation speed detection unit 111 receives the rotation position θ detected by the rotation position detection unit 110, calculates the angular velocity ω from the input rotation position θ, and outputs the angular velocity ω to the torque / current conversion unit 101.

  The torque / current conversion unit 101 receives the command torque Treq supplied from the ECU 10 and the angular velocity ω supplied from the rotation speed detection unit 111, and a current command necessary for the three-phase AC motor 50 to output the command torque Treq. The values of req_id and req_iq are obtained by searching from a table, for example. FIG. 4 shows the relationship between torque and current command. The horizontal axis represents torque (Nm), and the vertical axis represents current command (A). The torque and current command (d-axis, q-axis) values having the relationship as shown in FIG. 4 may be stored in advance in a table and read when performing current control. Specifically, the values of current commands req_id and req_iq necessary for outputting a predetermined torque are obtained in advance by experiments and stored as table data in the table storage unit 1151. Then, when performing current control, the values of the current commands req_id and req_iq corresponding to the command torque Treq may be read from the table of the table storage unit 1151.

On the other hand, the three-phase / two-phase current conversion unit 114 includes the rotational position θ detected by the rotational position detection unit 110 and the values of the three-phase coil currents i _U , i _V , i _W detected by the three-phase current detection unit 112. Enter. The three-phase / two-phase current conversion unit 114 converts the input three-phase coil currents i _U , i _V , i _W into two-phase current values id, iq using the equation (1).

The subtractors 102 and 103 receive the current commands req_id and req_iq from the torque / current conversion unit 101, input the two-phase current values id and iq from the three-phase / two-phase current conversion unit 114, and calculate the current according to Equation (2). Deviations ed and eq are obtained and supplied to the current control unit 104. The current deviations ed and eq indicate the amount of two-phase current that should be increased or decreased in order to obtain the command torque.

The current control unit 104 inputs current commands req_id and req_iq from the torque / current conversion unit 101, and inputs current deviations ed and eq from the subtracters 102 and 103, respectively. Then, the current control unit 104 calculates the instruction voltages vd and vq from the current commands req_id, req_iq, and current deviations ed and eq, for example, by PI (Proportional Integral) control as shown in Expression (3). The command voltages vd and vq indicate a two-phase drive voltage necessary for obtaining the commanded torque Treq.
k0, k1, k2 constants

The two-phase / three-phase voltage conversion unit 105 inputs the calculated instruction voltages vd and vq from the current control unit 104 and the rotation position θ from the rotation position detection unit 110. The instruction voltage vd, vq is converted into instruction voltages rv _U , rv _V , and rv _W for three phases. The command voltages rv _U , rv _V , and rv _W represent drive voltages applied to each phase of the three-phase AC motor 50 in order to obtain the commanded torque Treq.

The disturbance observer 115 defines the basic expression of the three-phase current response as shown in Expression (5), and estimates the induced voltage E = [E _U , E _V , E _W ] ^T expressed by Expression (6). Here, the subscript “ ^T ” indicates a transposed matrix.

Here, v = [v _U , v _V , v _W ] ^T is a three-phase voltage vector, R is a series resistance (for example, 73.05 × 10 ⁻³ ), I is a 3 × 3 unit matrix, and i = [i _U , i _V , i _W ] ^T is a three-phase current vector, Ψ = [Ψ _U , Ψ _V , Ψ _W ] ^T is a vector display of the number of flux linkages, and θ is the rotational position of the rotor. The inductance matrix L represents the self-inductance and mutual inductance of the three-phase coil as a 3 × 3 matrix as shown in Equation (7).

  Hereinafter, a specific method for estimating the induced voltage E will be described.

In the table storage unit 1151, the three-phase self-inductances L _U , L _V , L _W obtained by analyzing the characteristics of the three-phase AC motor 50 in advance and the mutual inductances M _UV , M _UW , M _VU between the three phases are obtained. , M _VW , M _WU , and M _WV are stored with a three-dimensional table tbl that associates the rotational position θ with the coil currents i _U , i _V , and i _W. Based on this three-dimensional table tbl, the inductance search unit 1152 and the rotation position θ detected by the rotation position detection unit 110 and the coil currents i _U , i _V , i _W detected by the three-phase current detection unit 112. With reference to the three-dimensional table tlb, all elements (self-inductance and mutual inductance) of the inductance matrix L expressed by the equation (7) are searched from the value of and supplied to the induced voltage estimation unit 1153.

The induced voltage estimation unit 1153 includes the coil currents i _U , i _V , i _W detected by the three-phase current detection unit 112 and the voltage operation amounts v _U , v _V , v _W detected by the three-phase voltage detection unit 113. Then, the induced voltages E _U , E _V , and E _W are estimated from the matrix L composed of the self-inductance and the mutual inductance searched by the inductance search unit 1152. A method for estimating the induced voltages E _U , E _V and E _W will be described below.

First, A, B, C, and E are defined as arbitrary state space matrices, and a state space expression P _(s) of a three-phase current response is defined as in Expression (8).
The dot “•” above the symbol represents time differentiation.

Further, the filter of the disturbance observer 115 is defined as shown in Expression (9).
Note that τ is a time constant (for example, τ = 1/3000) s is a Laplace operator.

Here, considering (τs + 1) P _(s) , equation (8) can be transformed into equations (10) and (11).

Here, when A = RI, B = I, C = I, and E = L, and calculating the inverse matrix, Expression (12) can be expressed as Expression (13).

Therefore, the induced voltages E _U , E _V and E _W to be obtained are [E _U E _V E _W ] ^T , the coil currents i _U , i _V and i _W are [i _U i _V i _W ] ^T and the voltage manipulated variable v _U. , _{V V} , v _W are [v _U v _V v _W ] ^T , they can be expressed as in equation (14).
[X _U x _V x _W ] ^T and [y _U y _V y _W ] ^T are parameters.

From the equation (14), the induced voltage estimation unit 1153 estimates the induced voltages E _U , E _V , and E _W.

The multiplier 116 receives the induced voltages E _U , E _V , E _W obtained by the induced voltage estimator 1153, multiplies the input induced voltages E _U , E _V , E _W and the proportional gain K, and corrects the corrected voltage KE. _U , KE _V and KE _W are obtained and output to the subtracters 106, 107 and 108, respectively. For example, the proportional gain K can be K = 1.

The subtractors 106, 107, 108 receive the instruction voltages rv _U , rv _V , rv _W from the two-phase / three-phase voltage converter 105, respectively, and the correction voltages KE _U , KE _V , KE determined by the multiplier 116. _W is input from the multiplier 116. Then, the subtracter 106, 107, 108, the command voltage _{rv U,} calculates rv V, rv _W from the correction voltage _{KE U, KE V, KE W} was subtract the voltage manipulated variable _{v U, v V, v W} , Output to the PWM generator 109. The voltage operation amounts v _U , v _V , and v _W are corrected so as to cancel out fluctuations in the current corresponding to the induced voltage generated by each phase coil of the three-phase AC motor 50. Therefore, by applying the voltage manipulated variables v _U , v _V , and v _W to the three-phase AC motor 50, the current in which the influence of the induced voltage is reduced (removed), that is, each phase current having a waveform close to a sine wave is obtained. It can flow.

The PWM generation unit 109 inputs the voltage operation amounts v _U , v _V , and v _W calculated in the voltage correction calculation (FIG. 7: Step S9) from the subtractors 106, 107, and 108. Then, the PWM generation unit 109 outputs a PWM signal corresponding to the voltage operation amounts v _U , v _V , and v _W to the inverter 40. By this PWM signal, the inverter 40 adjusts the width of the pulse applied to each phase so that the voltage applied to the three-phase AC motor 50 becomes the voltage manipulated variables v _U , v _V , and v _W. The electric motor 50 is driven.
At this time, currents flowing through the coils of the respective phases are detected by the three-phase current detection unit 112 as coil currents i _U , i _V , i _W.

  Such a series of operations is steadily performed by the control device 100 of FIG. 1, whereby the three-phase AC motor 50 is driven by a coil current in which the induced voltage is corrected. Therefore, the drive current flowing through the coils of each phase is almost a sine wave current. Therefore, it is possible to provide an electric motor that has a small drive current fluctuation and generates less vibration and noise.

  Here, with reference to FIG. 5 and FIG. 6, the difference between the current response and the current motor control device according to the control device 100 of the present embodiment will be specifically described.

FIG. 5A is a relationship diagram between current response in the q-axis direction and time in a conventional motor control device.
FIG. 5B is a relationship diagram between current response in the d-axis direction and time in a conventional motor control device.

In FIG. 5A, the vertical axis represents the two-phase current value iq in the q-axis direction, and the horizontal axis represents time (sec). In FIG. 5B, the vertical axis represents the two-phase current value id in the d-axis direction, and the horizontal axis represents time (sec). 5 (a) and 5 (b), although there is a difference in phase and amplitude, they coincide with each other in that the current value changes periodically. In the conventional motor control device, the induced voltage generated by passing a current through the coil of the motor contains harmonic components, and as a result, the current responses of both the q-axis and d-axis contain harmonic components. is there. Here, the conventional motor control device refers to a motor control device configured such that the subtractors 106, 107, 108 do not correct the voltage manipulated variables v _U , v _V , v _W. The reason why harmonic components are contained in the induced voltage will be described below.

First, the number of interlinkage magnetic fluxes Ψ _f (Ψ _fU , Ψ _fV , Ψ _fW ) due to the field of the motor is _calculated by taking into consideration the harmonics up to the 7th order (ignoring components higher than the 7th order) (15 ).
Incidentally, [psi _fn represents the amplitude of the n th harmonic, phi _n represents the n-th harmonic of the phase.

Here, in the equation (15), when considering the equation (5) and dθ / dt = ω, the induced voltages E _U , E _V , and E _W can be expressed as the equation (16). Here, ω represents an angular velocity.

Here, when three-phase to two-phase conversion is performed, Expression (16) can be expressed as Expression (17). Note that Ed and Eq represent induced voltages in the d-axis direction and the q-axis direction.
Therefore, as shown in the equation (17), the induced voltages Ed and Eq contain sixth-order harmonics.

On the other hand, current response characteristics according to the driving method of the control device 100 of the present embodiment are shown in FIGS.
FIG. 6A is a relationship diagram of current response in the q-axis direction and time in the motor control device according to the present embodiment, and FIG. 6B is a d-axis in the motor control device according to the present embodiment. It is a current response of a direction and the relationship diagram of time.
In FIG. 6A, the vertical axis represents the two-phase current value iq in the q-axis direction, and the horizontal axis represents time (sec). In FIG. 6B, the vertical axis represents the two-phase current value id in the d-axis direction, and the horizontal axis represents time (sec). In FIGS. 6A and 6B, the periodic change of the current value is extremely small. The waveform is close to a sine wave. This is because, in a motor control apparatus according to the present embodiment, in the subtracter 106, 107, 108, command voltage _{rv U, rv V, rv W} from the correction voltage _{KE U, KE V, KE W} was subtracted respectively This is because the voltage manipulated variables v _U , v _V , and v _W are calculated. That is, the voltage manipulated variables v _U , v _V , and v _W are corrected so as to cancel the current fluctuation due to the harmonic component of the induced voltage generated by each phase coil of the three-phase AC motor 50. For this reason, a stable current flows through each phase coil of the three-phase AC motor 50 by passing a current through the three-phase AC motor 50 in accordance with the voltage manipulated variables v _U , v _V , and v _W.

  From FIG. 5A to FIG. 6B, the operation and effect of the driving method by the driving apparatus 100 according to the present embodiment can be confirmed.

  In addition, this invention is not limited to the said Example, A various deformation | transformation and application are possible.

  In the above embodiment, the torque / current conversion unit 101 uses the table to determine the values of the necessary current commands req_id and req_iq.

  In the above embodiment, the current control unit 104 calculates the instruction voltages vd and vq by PI control. However, the current control unit 104 may calculate the instruction voltages vd and vq by other control methods such as P control and PID control.

In the above embodiment, the inductance search unit 1152 searches for the inductance from the three-dimensional table tbl with respect to the rotational position θ and the coil currents i _U , i _V , i _W , but it is not always necessary to use the three-dimensional table tbl. The inductance may be obtained by calculation from the above approximate expression or the like.

In the above embodiment, the multiplication unit 116 multiplies the induced voltages E _U , E _V , E _W and the proportional gain K to obtain the correction voltages KE _U , KE _V , KE _W , but a multiplier is always used. There is no need, and an arithmetic unit that performs simple calculation may be used instead of the multiplier.

In the above embodiment, the correction voltages KE _U , KE _V , and KE _W obtained by the multiplication unit 116 are directly output to the subtracters 106, 107, and 108, but may be output after passing through a high-pass filter. .

In the above-described embodiment, the voltage manipulated variables v _U , v _V , and v _W that are three-phase voltages are corrected. However, the correction is also performed for the instruction voltages vd and vq that are two-phase voltages. Good. In this case, the induced voltage is estimated in a disturbance observer on two phases.

  In the above embodiment, the control device 100 is described as being configured with discrete components. However, for example, most of the processing executed by the control device 100 is performed by a CPU (Central Processing Unit) or a DSP (Digital Signal Processor). It is also possible to execute it by a processor circuit such as. With such a configuration, the circuit configuration can be simplified. In this case, the outputs of various sensors are digitized by an A / D converter or the like. The output of the processor is analogized and supplied by a D / A converter as necessary.

  An example of a processing procedure performed when the processor in this case executes the program will be described with reference to FIGS.

First, the processor inputs the rotational position θ from the rotational position detection unit 110, and inputs the values of the three-phase coil currents i _U , i _V , i _W from the three-phase current detection unit 112, and the three-phase voltage detection unit 113. voltage manipulated variable from _{v U, v V,} and inputs the value of _{v W} (step S1).
Subsequently, the processor inputs the instruction torque Treq from the ECU 10, calculates the angular velocity ω, and calculates the two-phase current commands req_id and req_iq (step S2).

Subsequently, the processor obtains the two-phase current values id and iq from the rotational position θ and the values of the three-phase coil currents i _U , i _V and i _W according to the equation (1) (step S3).

  Subsequently, the processor subtracts the two-phase current values id and iq from the current commands req_id and req_iq, respectively, to obtain the two-phase current deviations ed and eq (step S4).

  Subsequently, the processor calculates the two-phase command voltages vd and vq from the two-phase current deviations ed and eq, for example, by PI control (step S5).

Subsequently, the processor obtains the three-phase command voltages rv _U , rv _V , and rv _W by the equation (4) using the two-phase command voltages vd and vq and the rotational position θ (step S6).

  Subsequently, the processor estimates an induced voltage (step S7).

In the induced voltage estimation process (step S7), as shown in FIG. 8, the processor obtains an inductance matrix L at that time (step S701). That is, the three-dimensional table tbl is searched from the rotational position θ and the coil currents i _U , i _V , i _W and all elements of the inductance matrix L are obtained.

Subsequently, the processor executes induced voltage estimation (step S702). Here, the processor induces the coil currents i _U , i _V , i _W , the voltage manipulated variables v _U , v _V , v _W and the inductance matrix L in accordance with the equations (8) to (14) and the like. voltage _{E U, E V,} to estimate the _{E W.}

Subsequently, the processor proceeds to step S8 and multiplies the induced voltages E _U , E _V , E _W and the proportional gain K to obtain correction voltages KE _U , KE _V , KE _W (step S8).

Subsequently, the processor subtracts the correction voltages KE _U , KE _V , KE _W from the instruction voltages rv _U , rv _V , rv _W to calculate voltage manipulated variables v _U , v _V , v _W (step S9).

Subsequently, the processor outputs a PWM signal corresponding to the voltage manipulated variables v _U , v _V , and v _W to the inverter 40 (step S10). With this PWM signal, the inverter 40 drives the three-phase AC motor 50 through the coil currents i _U , i _V , i _W.

  Subsequently, the processor returns control to step S1.

  Such processing enables control similar to that of the control device 100 of FIG. Note that the flowcharts described in the above embodiments are examples of the embodiments and are not limited to these processing routines.

1 is a block diagram illustrating an overall configuration of a motor control device according to an embodiment of the present invention. It is a figure for demonstrating the function of the inverter shown in FIG. (A) is a relationship figure of the rotation position of a rotor, a coil current, and a self-inductance. (B) is a relationship diagram of the rotational position of the rotor, the coil current, and the mutual inductance. It is a figure showing the relationship between a torque and an electric current command. (A) is a relational diagram between current response in the q-axis direction and time in a conventional motor control device. (B) is a relational diagram between current response in the d-axis direction and time in a conventional motor control device. (A) is a relational diagram between current response in the q-axis direction and time in the motor control apparatus according to the present embodiment. FIG. 5B is a relationship diagram between current response in the d-axis direction and time in the motor control device according to the present embodiment. It is a flowchart for demonstrating the control processing of a processor when the principal part of a control apparatus is comprised with a processor. It is a flowchart for demonstrating the induced voltage estimation process in the flowchart of FIG.

Explanation of symbols

10 ECU
20 DC power supply 30 Capacitor 40 Inverter 50 Three-phase AC motor 101 Torque / current converter 102 Subtractor 103 Subtractor 104 Current controller 105 Two-phase / three-phase voltage converter 106 Subtractor (Correction means)
107 Subtractor (Correction means)
108 Subtractor (Correction means)
109 PWM generator (drive means)
110 Rotation position detection unit (Rotation position detection means)
111 Rotational Speed Detection Unit 112 Three-phase Current Detection Unit (Current detection means)
113 Three-phase voltage detector (Voltage detector)
114 Three-phase / two-phase current converter 115 Disturbance observer (Inductance search means, induced voltage estimation means)
1151 Table storage unit
1152 Inductance search unit (inductance search means)
1153 induced voltage estimation unit (induced voltage estimation means)
116 Multiplier

Claims (10)

Induced voltage estimating means for estimating the induced voltage generated in the coil of the motor;
Correction means for correcting and outputting an instruction signal indicating a drive voltage for driving the electric motor based on the induced voltage estimated by the induced voltage estimation means;
An electric motor control device comprising: The correction means corrects the drive voltage based on the induced voltage estimated by the induced voltage estimation means so that the current flowing in the coil of the electric motor becomes a sine wave.
The motor control device according to claim 1. The induced voltage estimation means includes:
Current detection means for detecting the current value of the current flowing in the coil of the motor;
An inductance discriminating means for discriminating the inductance of the coil of the electric motor;
Means for estimating the induced voltage of the coil of the motor based on the current value detected by the current detection means and the inductance determined by the inductance determination means;
The motor control device according to claim 1, wherein the motor control device is provided. The induced voltage estimation means includes:
Current detection means for detecting the current value of the current flowing in the coil of the motor;
Voltage operation amount detection means for detecting the operation amount of the voltage applied to the coil of the electric motor;
An inductance discriminating means for obtaining the inductance of the coil of the motor;
The induced voltage of the motor is estimated based on the current value detected by the current detection means, the operation amount of the applied voltage detected by the voltage operation amount detection means, and the inductance determined by the inductance determination means. Means,
The motor control device according to claim 1, wherein the motor control device is provided. The induced voltage estimation means includes:
A table for storing the inductance of the coil in association with the rotational position of the rotor of the electric motor and the current value of the current flowing through the coil;
Rotational position detecting means for detecting the rotational position of the rotor;
Current detection means for detecting the current value of the current flowing in the coil of the motor;
Inductance discrimination means for searching the table based on the rotational position detected by the rotational position detection means and the current value detected by the current detection means to obtain the inductance of the coil;
The induced voltage of the motor is estimated based on the current value detected by the current detection means, the operation amount of the applied voltage detected by the voltage operation amount detection means, and the inductance determined by the inductance determination means. Means,
The motor control device according to claim 1, wherein the motor control device is provided. The motor control device further includes a multiplying unit that multiplies the value estimated by the induced voltage estimating unit,
6. The motor control apparatus according to claim 1, wherein the correction unit corrects an instruction voltage for controlling the electric motor based on a value multiplied by the multiplication unit. . Drive means for driving and controlling the motor with the drive voltage indicated by the drive voltage instruction signal corrected by the correction means;
The motor control device according to claim 1, further comprising: An instruction signal generating means for generating an instruction signal for instructing a driving voltage of the electric motor;
Drive current detection means for detecting the current flowing in the coil of the electric motor;
Correction means for correcting the instruction value generated by the instruction signal generation means so that the waveform of the drive current detected by the drive current detection means approaches a sine wave;
An electric motor control device comprising: An induced voltage estimation step for estimating the induced voltage generated in the coil of the motor;
A correction step of correcting and outputting an instruction signal of a drive voltage for driving the electric motor based on the estimated induced voltage;
An electric motor control method comprising: On the computer,
An induced voltage estimation step for estimating the induced voltage generated in the coil of the motor;
A correction step of correcting and outputting an instruction signal of a drive voltage for driving the electric motor based on the estimated induced voltage;
A computer program that implements