JP2014158336A - Motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent torque pulsation and noise generation while maintaining a high responsiveness of control.SOLUTION: A motor controller 100 of an embodiment comprises: a detected current conversion unit 112 for converting a detected three-phase current to a d-axis current and a q-axis current on dq coordinate axis referenced to a phase angle of a rotor of a three-phase synchronous motor 110; a coordinate axis conversion unit 113 for converting the d-axis current and the q-axis current respectively to a γ-axis current and a δ-axis current on γδ coordinate axis which is an estimated coordinate axis lagging by an error angle from the dq coordinate axis; an error angle estimation unit 114 for estimating an error angle of phase angle on the basis of a disturbance observer using output from a rotation detection unit 107 for an extended induced voltage equation on the γδ coordinate axis having the γ-axis current and δ-axis current as input parameters; a phase angle correction unit (deviation arithmetic unit) 111 for correcting the phase angle with the estimated error angle; and a voltage conversion unit 104 for converting a command d-axis voltage and a command q-axis voltage on the dq coordinate axis to a command three-phase voltage on the basis of the corrected phase angle.

Description

  Embodiments described herein relate generally to a motor control device.

  In recent years, a technique for applying an inverter to a control device for an AC motor such as a three-phase synchronous motor has become widespread, and the control performance has been significantly improved as compared with the conventional technology. In the motor control device to which the inverter is applied, the phase of the applied rectangular wave voltage is controlled by detecting and feeding back the current of each phase flowing in the armature winding of the AC motor, based on the command torque from the outside. In many cases, the current is controlled by controlling the effective voltage value by a pulse width modulation (PWM) method.

  As a torque control method for such an AC motor, a voltage equation in a U-phase, V-phase, and W-phase three-phase fixed coordinate system is converted into a dq coordinate two-phase rotary coordinate system with reference to the phase angle of the rotor magnet. Vector control that performs conversion and performs current control of an AC motor is known. In this vector control, the control device detects the phase angle of the rotor of the AC motor, calculates the angular velocity, performs control calculation on the dq coordinate axis, and performs current control.

JP 2001-298990 A

  In such vector control, the phase angle of the rotor of the AC motor is detected by a resolver or the like that is an angle sensor, but the phase angle detected by the resolver or the like has an error angle such as a resolver rotation primary or secondary. May occur. Such an error angle makes it difficult to appropriately control the current with respect to the phase angle, and causes torque pulsation and noise.

  Here, in the method of feeding back the offset of the three-phase current and controlling the current of the AC motor to avoid the occurrence of torque pulsation and noise, it is necessary to feed back the current value for one round of the three phases, and the control with high response is performed. It is difficult to realize.

  The motor control device of the embodiment includes a current detection unit that detects a three-phase current flowing in a three-phase motor, a rotation detection unit that detects a phase angle at which a rotor of the three-phase motor rotates, Is converted into a d-axis current and a q-axis current on the dq coordinate axis with reference to the phase angle of the rotor of the three-phase motor, and the d-axis current and the q-axis current are converted into the dq coordinate axis. A coordinate axis conversion unit for converting each of the γ-axis current and the δ-axis current on the γδ coordinate axis, which is an estimated coordinate axis delayed by an error angle, and the three-phase motor using the γ-axis current and the δ-axis current as input parameters The error angle of the phase angle is estimated based on the disturbance observer using the output from the rotation detection unit with respect to the extended induced voltage equation on the γδ coordinate axis with respect to the extended induced voltage that is an apparent induced voltage. An error angle estimator, a phase angle corrector that corrects the phase angle with the estimated error angle, and a command d-axis voltage and a command q-axis voltage on the dq coordinate axis based on the corrected phase angle, Based on the command three-phase voltage, a voltage conversion unit that converts the command to the three-phase voltage, and generates an actual three-phase voltage and applies the three-phase motor to the three-phase motor. And a power converter for flowing. With this configuration, for example, torque pulsation and noise generation can be prevented while maintaining high control responsiveness.

  In the motor control device of the embodiment, the detected current conversion unit converts the detected three-phase current into a d-axis current and a q-axis current using the corrected phase angle. With this configuration, as an example, the accuracy of vector control can be improved.

  Further, in the motor control device of the embodiment, the disturbance observer is a differential equation for estimating the expansion induced voltage, and the error angle estimation unit is configured to calculate the γ-axis expansion induced voltage and δ on the γδ coordinate based on the disturbance observer. An axis expansion induced voltage is obtained, and an error angle is estimated from the γ-axis expansion induced voltage and the δ-axis expansion induced voltage. With this configuration, for example, torque pulsation and noise generation can be prevented while maintaining high control responsiveness.

  In the motor control device of the embodiment, the disturbance observer uses the angular velocity of the rotor based on the phase angle as a parameter. With this configuration, for example, torque pulsation and noise generation can be prevented while maintaining high control responsiveness.

  In the motor control device of the embodiment, a current command unit that calculates a command d-axis current and a command q-axis current on the dq coordinate axis based on a command torque from the outside, a d-axis current, a q-axis current, And a voltage calculation unit that calculates a command d-axis voltage and a command q-axis voltage based on the command d-axis current and the command q-axis current.

FIG. 1 is a block diagram illustrating an overall configuration of a motor control device 100 according to the embodiment. FIG. 2 is a diagram illustrating the relationship between the dq coordinate axis and the γδ coordinate axis. FIG. 3 is a flowchart showing the procedure of the motor control process of the present embodiment.

A motor control device 100 according to an embodiment will be described. FIG. 1 is a block diagram illustrating an overall configuration of a motor control device 100 according to the embodiment. The motor control device 100 is configured to include a computer that operates by software. The control target is the three-phase currents i _u , i _v , i _w of the three-phase synchronous motor 110, and the control amount is the three-phase synchronous motor 110. Are the three-phase voltages v _u , v _v and v _w applied to. Here, the motor control device 100 and the three-phase synchronous motor 110 of the present embodiment are mounted on a hybrid vehicle as an example, but are not limited thereto.

The three-phase synchronous motor 110 is an embedded magnet synchronous motor configured by embedding a magnet in a rotor core (not shown) and winding an armature winding around a stator core (not shown). However, it may be a three-phase motor, and is not limited to this. The motor control device 100 controls the three-phase voltages v _u , v _v , and v _w so as to output a torque equal to the torque command Req_trq received from the outside from the three-phase synchronous motor 110.

  As shown in FIG. 1, the motor control device 100 includes two current detection units 108a and 108b, a rotation detection unit 107, a deviation calculator 111, a detection current conversion unit 112, a coordinate axis conversion unit 113, an error It mainly includes an angle estimation unit 114, a rotation speed calculation unit 115, a current command unit 101, a voltage calculation unit 120, a voltage conversion unit 104, and a power conversion unit 130.

The two current detection units 108a and 108b are provided on the V-phase input line and the W-phase input line among the three-phase input lines connected to the armature winding of the three-phase synchronous motor 110, respectively. The current detection units 108a and 108b can be configured by using, for example, a known current transformer or a shunt resistor, and detect the V-phase current i _v and the W-phase current i _w and detect the detection signals. Output to the current converter 112. The detected current conversion unit 112 calculates the third-phase U-phase current i _u by using the fact that the vector sum of the three-phase currents i _u , i _v , i _w is zero.

  The rotation detection unit 107 is an angle sensor that detects a phase angle θ at which the rotor of the three-phase synchronous motor 110 rotates. In the present embodiment, a resolver is used as the rotation detection unit 107. The phase angle θ detected by the rotation detector 107 is corrected by a deviation calculator 111 described later, and the corrected phase angle is sent to the rotation speed calculator 115 and the voltage converter 104.

The detected current conversion unit 112 converts the detected three-phase currents i _u , i _v , i _w into a d-axis current i _d and a q-axis current i _q on the dq coordinate axis using a phase angle after correction described later. To do. The detection current conversion unit 112 calculates the d-axis current i _d and the q-axis current i _q from the three-phase currents i _u , i _v , i _w by a known conversion formula using the phase angle θ, and the voltage calculation unit 120.

Here, the d-axis current i _d is a d-axis component of the current (armature current) flowing in the armature winding of the three-phase synchronous motor 110, and the q-axis current i _q is the q-axis component of the armature current. It is. The d-axis voltage v _d is a d-axis component of the voltage (armature voltage) applied to the armature winding of the three-phase synchronous motor 110, and the q-axis voltage v _q is the q-axis component of the armature voltage. It is.

On the dq coordinate axis, the extended induced voltage equation regarding the extended induced voltage, which is the apparent induced voltage of the three-phase synchronous motor 110, is expressed by the following equation (1) using the d-axis current i _d and the q-axis current i _q as input parameters. It is represented by

When the extended induced voltage equation of the equation (1) is converted from the dq coordinate system to the γδ coordinate system, the expanded induced voltage using the γ-axis current i _γ and the δ-axis current i _δ as input parameters as shown in the equation (2). It becomes an equation.

  Here, the γδ coordinate axis is an estimated coordinate axis delayed by an error angle from the dq coordinate axis. FIG. 2 is a diagram illustrating the relationship between the dq coordinate axis and the γδ coordinate axis. As shown in FIG. 2, the γδ coordinate axis is a coordinate axis delayed by an error angle from the dq coordinate axis. Here, reference numeral 107 a is a rotor of the three-phase synchronous motor 110.

Coordinate conversion unit 113, a d-axis current i _d and the q-axis current i _q on converted by the detection current conversion unit 112 dq coordinate axis, gamma-axis current i _gamma and δ-axis on γδ coordinate axes as shown in FIG. 2 It converts into each of electric current _idelta .

Here, the γ-axis current i _γ is a γ-axis component of the current (armature current) flowing in the armature winding of the three-phase synchronous motor 110, and the δ-axis current i _δ is the δ-axis component of the armature current. It is. The γ-axis voltage v _γ is a γ-axis component of the voltage (armature voltage) applied to the armature winding of the three-phase synchronous motor 110, and the δ-axis voltage v _δ is the δ-axis component of the armature voltage. It is.

  Returning to FIG. 1, the error angle estimation unit 114 estimates the error angle of the phase angle θ based on the disturbance observer for the extended induced voltage equation on the γδ coordinate axis expressed by the equation (2).

  In the error angle estimation unit 114, a disturbance observer shown in the following equation (3) is set.

  The disturbance observer is a differential equation for estimating the extended induced voltage, and uses an angular velocity ω based on the phase angle θ, which is an output from the rotation detection unit 107, as a parameter.

The error angle estimation unit 114 obtains the angular velocity ω of the rotor from the phase angle θ detected by the rotation detection unit 107. Specifically, the error angle estimation unit 114 calculates the angular velocity ω by dividing the change amount of the phase angle θ obtained by the two detections by the elapsed time. Then, the error angle estimation unit 114 sequentially inputs the γ-axis current i _γ , the δ-axis current i _δ , the γ-axis voltage v _γ , and the δ-axis voltage v _δ, and the disturbance observer of the expression (3) is obtained by a known numerical analysis. By solving, the γ-axis expansion induced voltage (γ-axis component of the expansion induced voltage) and the δ-axis expansion induced voltage (δ-axis component of the expansion induced voltage) on the γδ coordinates are estimated. Then, the error angle estimation unit 114 estimates the error angle using the following equation (4) from the γ-axis expansion induced voltage and the δ-axis expansion induced voltage.

  Here, the derivations of equations (1) to (4) are derived from non-patent literature “Shigeo Morimoto, Keisuke Kawamoto, Yoji Takeda:“ IPMSM Position / Velocity Sensorless Control Using Estimated Position Error Information ”, Electrical Theory D, Vol. 122-D, no. 5 pp. 722-729 (2002) ".

  The deviation calculator 111 functions as a phase angle correction unit, and subtracts the error angle estimated by the error angle estimation unit 114 from the phase angle θ detected by the rotation detection unit 107, as shown in equation (5). Thus, the phase angle θ is corrected.

  The rotation number calculation unit 115 calculates the rotation number of the rotor of the three-phase synchronous motor 110 from the phase angle θ detected by the rotation detection unit 107, and sends the calculated rotation number to the ECU of the hybrid vehicle.

Current command unit 101 converts the torque command Req_trq received from the outside to the command d-axis current Req_i _d and command q-axis current Req_i _q, commands the voltage calculating unit 120. This conversion process can be performed using, for example, a maximum torque / current control method, but is not limited thereto.

Voltage calculating unit 120, based on the d-axis current i _d and the q-axis current i _q output from the detection current conversion unit 112, the command d-axis current Req_i _d and command q-axis current Req_i _q output from the current command section 101 The command d-axis voltage Req_v _d and the command q-axis voltage Req_v _q are calculated and commanded to the voltage conversion unit 104.

Specifically, as shown in FIG. 1, the voltage calculator 120 includes two deviation calculators 102a and 102b and two proportional-plus-integral controllers (PI) 103a and 103b. Deviation calculator 102a subtracts the d-axis current i _d from the command d-axis current Req_i _d calculates the deviation e_i _d, passes deviation e_i _d proportional integral controller (PI) 103a. PI controller (PI) 103a adds integrated value time values and deviation e_i _d multiplied by a predetermined proportionality constant seeking command d-axis voltage req_v _d relative deviation e_i _d, command d-axis voltage Req_v _d is output to the voltage converter 104.

Further, the deviation calculator 102b subtracts the q-axis current i _q from the command d-axis current Req_i _q calculates a deviation e_i _q, passes deviation e_i _q proportional integral controller (PI) 103b. PI controller (PI) 103b adds integrated value time values and deviation e_i _q multiplied by a predetermined proportionality constant seeking command q-axis voltage req_v _q relative deviation e_i _q, command q-axis voltage Req_v _q is output to the voltage converter 104.

The voltage conversion unit 104 converts the command d-axis voltage Req_v _d and the command q-axis voltage Req_v _q into command three-phase voltages Req_v _u , Req_v _v , Req_v _w by a known conversion formula using the corrected phase angle θ. The power conversion unit 130 is commanded.

The power conversion unit 130 includes a PWM control unit 105 and an inverter 106. The PWM control unit 105 determines the duty ratio of each phase from the command three-phase voltages Req_v _u , Req_v _v , Req_v _w and sequentially outputs them to the inverter 106. The inverter 106 generates actual three-phase voltages v _u , v _v , v _w based on the duty ratio of each phase and applies them to the armature windings of the three-phase synchronous motor 110. As a result, three-phase currents i _u , i _v and i _w flow through the armature winding of the three-phase synchronous motor 110.

  Next, the motor control process of the present embodiment configured as described above will be described. FIG. 3 is a flowchart showing the procedure of the motor control process of the present embodiment. FIG. 3 shows processing from detection of the phase angle θ, v-phase current, and w-phase current to correction of the phase angle θ in the entire motor control processing.

First, the rotation detection unit 107 such as a resolver detects the phase angle θ of the rotor of the three-phase synchronous motor 110 (step S11). The current detection unit 108a, 108b detects the V-phase current i _v, and the W-phase current i _w respectively from V-phase input line and W phase input line (step S12), the respective detection signals to the detected current converter 112 Output.

Then, the detection current conversion unit 112 calculates the U-phase current i _u using the fact that the vector sum of the three-phase currents i _u , i _v , i _w is zero (step S13). Next, the detected current conversion unit 112 converts the three-phase currents i _u , i _v , i _w into a d-axis current i _d and a q-axis current i _q on the dq coordinate axis (step S14). The detected current conversion unit 112 outputs the d-axis current i _d and the q-axis current i _q to the deviation calculators 102 a and 102 b and the coordinate axis conversion unit 113.

Coordinate conversion unit 113 receives the d-axis current i _d and the q-axis current i _q, converts the d-axis current i _d and the q-axis current i _q on the γδ coordinate axes gamma in the axial current i _gamma and [delta] -axis current i _[delta] (Step S15).

  Next, the error angle estimator 114 calculates the estimated value of the γ-axis expansion induced voltage and the estimated value of the δ-axis expansion induced voltage by solving the disturbance observer of the above-described equation (3) by a known numerical analysis method. (Step S16). Then, the error angle estimation unit 114 calculates the error angle from the above-described equation (4) using the estimated value of the γ-axis expansion induced voltage and the estimated value of the δ-axis expansion induced voltage (step S17).

Next, the deviation calculator 111 subtracts the error angle estimated by the error angle estimation unit 114 from the phase angle θ detected by the rotation detection unit 107 according to the above-described equation (5), thereby obtaining the phase angle θ. Is corrected (step S18). The corrected phase angle is output to rotation calculation section 115, detection current conversion section 113, detection current conversion section 112 and voltage conversion section 104. The detected current conversion unit 112 converts the three-phase currents i _u , i _v , i _w into a d-axis current i _d and a q-axis current i _q on the dq coordinate axis using the corrected phase angle. The voltage conversion unit 104, using the phase angle after correction, converts the command d-axis voltage req_v _d and command q-axis voltage req_v _q command three-phase voltage req_v _u, req_v _v, the req_v _w. Thus, the corrected phase angle is used for conversion between the three-phase fixed coordinate system and the two-phase rotating coordinate system.

  As described above, in this embodiment, the disturbance observer using the output of the rotation detection unit 107 such as a resolver as a parameter for the extended induced voltage equation obtained by converting the extended induced voltage equation on the dq coordinate axis of the three-phase synchronous motor 110 into the γδ coordinate axis. And the error angle of the phase angle is estimated by estimating the expansion induced voltage by the disturbance observer, so that the phase angle θ can be corrected with high response.

  Moreover, in this embodiment, since the phase angle after correction | amendment is utilized for conversion between a three-phase fixed coordinate and a two-phase rotation coordinate, the precision of vector control can be improved. As described above, in the present embodiment, since the accuracy of vector control is improved, torque pulsation and noise generation can be prevented while maintaining high control response.

  Further, in this embodiment, the phase induced error is estimated by estimating the expansion induced voltage and the phase angle θ is corrected, so that it is possible to calculate an angular velocity that is less influenced by errors such as a resolver.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

101 Current command units 102a, 102b, 111 Deviation calculators 103a, 103b Proportional integral controller (PI)
104 Voltage conversion unit 105 PWM control unit 106 Inverter 107 Rotation detection unit 108a, 108b Current detection unit 110 Three-phase synchronous motor 111 Deviation calculator 112 Detection current conversion unit 113 Coordinate axis conversion unit 114 Error angle estimation unit 115 Rotation number calculation unit 120 Voltage Calculation unit 130 Power conversion unit

Claims (5)

A current detector for detecting a three-phase current flowing in the three-phase motor;
A rotation detector that detects a phase angle at which the rotor of the three-phase motor rotates;
A detected current converter that converts the detected three-phase current into a d-axis current and a q-axis current on the dq coordinate axis with reference to the phase angle of the rotor of the three-phase motor;
A coordinate axis converter that converts the d-axis current and the q-axis current into a γ-axis current and a δ-axis current on a γδ coordinate axis, which is an estimated coordinate axis delayed by an error angle from the dq coordinate axis,
Using the output from the rotation detection unit for the extended induced voltage equation on the γδ coordinate axis related to the extended induced voltage that is the apparent induced voltage in the three-phase motor using the γ-axis current and the δ-axis current as input parameters. An error angle estimator that estimates an error angle of the phase angle based on a disturbance observer;
A phase angle correction unit that corrects the phase angle with the estimated error angle;
A voltage converter that converts the command d-axis voltage and the command q-axis voltage on the dq coordinate axis into a command three-phase voltage based on the corrected phase angle;
Based on the command three-phase voltage, by generating an actual three-phase voltage and applying it to the three-phase motor, a power converter that passes the three-phase current to the three-phase motor;
A motor control device comprising: The detected current conversion unit converts the detected three-phase current into the d-axis current and the q-axis current using the corrected phase angle.
The motor control device according to claim 1. The disturbance observer is a differential equation for estimating the extended induced voltage,
The error angle estimation unit obtains a γ-axis expansion induced voltage and a δ-axis expansion induced voltage on the γδ coordinate based on the disturbance observer, and calculates the error angle from the γ-axis expansion induced voltage and the δ-axis expansion induced voltage. Estimate
The motor control device according to claim 1 or 2. The disturbance observer uses the angular velocity of the rotor based on the phase angle as a parameter,
The motor control apparatus as described in any one of Claims 1-3. A current command unit that calculates a command d-axis current and a command q-axis current on the dq coordinate axis based on a command torque from the outside;
A voltage calculator that calculates the command d-axis voltage and the command q-axis voltage based on the d-axis current, the q-axis current, the command d-axis current, and the command q-axis current;
The motor control device according to any one of claims 1 to 4, further comprising:

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