JP2011083112A - Controller of permanent magnet-type three phase ac motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To output much more torque while weakened magnetic flux control is established in a region where three phase output voltage limited by a voltage value of a DC power supply of an inverter is saturated and a permanent magnet-type three phase AC motor is controlled by weakened magnetic flux. <P>SOLUTION: The motor includes a d-axis voltage limiter limiting a d-axis voltage command value serving as output of a d-axis current controller and a q-axis voltage limiter limiting a q-axis voltage command value serving as output of a q-axis current controller. The d-axis voltage limiter limits the d-axis voltage command value by maximum output voltage decided by a voltage value of the DC power supply of the inverter. The q-axis voltage limiter limits the q-axis voltage command value by a variable limiter, which is calculated from the maximum output voltage decided by the voltage value of the DC power supply of the inverter and the d-axis voltage command value limited by the d-axis voltage limiter. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electric motor control device that controls a permanent magnet type three-phase AC motor, and more particularly to a voltage limiter for controlling magnetic flux by weakening a permanent magnet type three-phase AC motor.

  An example in which a voltage limiter is provided in the control of a conventional permanent magnet type three-phase AC motor is applied to Patent Document 1.

  FIG. 3 shows a part of the control configuration of the permanent magnet type three-phase AC motor applied to Patent Document 1, and the conventional technique will be described with reference to FIG.

  A three-phase balanced AC voltage is applied to the permanent magnet type three-phase AC motor 1 by an inverter 2 and a three-phase AC current flows.

  The U-phase current iu, V-phase current iv, and W-phase current iw flowing through the permanent magnet type three-phase AC motor 1 are detected by current detectors 31 to 33.

  The three-phase-dq rotational coordinate converter 6 is based on the U-phase current value iu, the V-phase current value iv, the W-phase current value iw and the position information θ from the position detector 7 attached to the permanent magnet type three-phase AC motor 1. The three-phase-dq rotational coordinate conversion is performed based on the equations (1) and (2), and a d-axis current id and a q-axis current iq that can be handled as a DC state on the rotational coordinates are output.

  The d-axis current id and the q-axis current iq are fed back, and the deviation between the d-axis current command idref and the d-axis current id, which is the output of the d-axis current command generator 11, is input to the d-axis current controller 10 and the d-axis voltage. The command Vdref1 is output, the deviation between the q-axis current command iqref and the q-axis current iq, which is the output of the q-axis current command generator 8, is input to the q-axis current controller 9, and the q-axis voltage command Vqref1 is output. .

  Since the voltage that can be output by the inverter 2 depends on the voltage value of the inverter DC power supply 4, the q-axis voltage command Vqref 1 is limited to a range in which the inverter 2 can be output by the q-axis voltage command limiter 13.

  The q-axis voltage command limiter 13 decreases the limit value when the inverter DC power supply 4 is low, and increases the limit value when the inverter DC power supply 4 is high.

  By changing the q-axis voltage command limiter 13 in this way, electric power can be appropriately supplied to the permanent magnet type AC electric motor 1.

  However, when the rotational speed of the permanent magnet type three-phase AC motor 1 increases, a large counter electromotive force is generated. Therefore, the inverter 2 limited by the voltage value of the inverter DC power supply 4 is output only by the limitation by the q-axis voltage command limiter 13. There is a risk of exceeding the range of possible voltages.

  As a method of controlling the permanent magnet three-phase AC motor 1 at a rotational speed that exceeds the voltage range that can be output by the inverter 2, a weak magnetic flux control that weakens the magnetic flux by flowing a negative d-axis current is known. .

  Since the d-axis voltage command Vdref1 which is the output of the d-axis current controller 10 is also increased in the region where the flux-weakening control is performed, the q-axis voltage command Vqref1 and the d-axis are set in order to keep the output voltage within a range where the inverter can output. A voltage limiter that considers both of the voltage command Vdref1 is required.

JP 2006-262669 A

  The problem to be solved is that when the magnetic flux control is performed by weakening the permanent magnet three-phase AC motor at a rotational speed that exceeds the voltage range that the inverter can output, the voltage is weakened within the voltage range that the inverter can output. It is to be able to output more torque while establishing magnetic flux control.

According to claim 1 of the present invention, an inverter for applying a voltage based on a three-phase AC voltage command to a permanent magnet type three-phase AC motor and a current detection for detecting a three-phase AC current flowing through the permanent magnet type three-phase AC motor, respectively. And a three-phase-dq rotational coordinate converter that converts the detected value of the three-phase alternating current into a d-axis current and a q-axis current, and the d-axis current is fed back and controlled to match the d-axis current command value. An axis current controller, a q-axis current controller that feeds back the q-axis current and controls it to match the q-axis current command value, and a d-axis that limits the d-axis voltage command value output from the d-axis current controller A q-axis voltage limiter that limits the q-axis voltage command value that is output from the voltage limiter and the q-axis current controller, a d-axis voltage command that passes through the d-axis voltage limiter, and a q-axis voltage that passes through the q-axis voltage limiter Convert command to the three-phase AC voltage command Dq-three-phase rotational coordinate converter, the output voltage of the inverter is limited by the voltage value of the DC power supply of the inverter, and the vector sum of the d-axis voltage command value and the q-axis voltage command value has a limit value. In the case of exceeding, the d-axis current command generator increases the d-axis current command value in the negative direction to generate a flux-weakening current command, so that the permanent magnet type three-phase is performed while avoiding output voltage saturation. In a control device that drives an AC motor,
The d-axis voltage limiter is limited by the maximum output voltage value determined by the voltage value of the DC power supply of the inverter, and the q-axis voltage limiter is the maximum output voltage determined by the voltage value of the DC power supply of the inverter and the d It is limited by a variable limiter calculated from the d-axis voltage command value limited by the axis voltage limiter.

According to a second aspect of the present invention, the limit value of the d-axis voltage limiter is determined by the equation (3) from the voltage value of the DC power supply of the inverter, and the limit value of the q-axis voltage limiter is the voltage value of the DC power supply of the inverter. The maximum output voltage determined in accordance with the d-axis voltage limiter is determined from the d-axis voltage command value limited by the d-axis voltage limiter according to the equation (4).

  According to claim 3 of the present invention, in the current controller in which the d-axis current controller and the q-axis current controller of claim 1 are each composed of a proportional device and an integrator, the integrator of the d-axis current controller Is limited to the d-axis voltage limiter, and the integrator value of the q-axis current controller is limited to the q-axis current limiter.

  When driving a permanent magnet type three-phase AC motor in a rotational speed range that exceeds the voltage that can be output by the inverter, more torque can be achieved while establishing flux-weakening control within the voltage range that the inverter can output. Can be output.

FIG. 2 is a block diagram showing a configuration of claims 1 and 2. Example 1 It is a block diagram showing the configuration of claim 3. (Example 2) It is the block diagram which showed the structure of background art.

  The purpose of controlling a permanent magnet type three-phase AC motor to output more torque while establishing flux-weakening control in a state where the output voltage of the inverter is saturated.

  FIG. 1 shows an embodiment in which claims 1 and 2 of the present invention are applied to a permanent magnet type three-phase AC motor, and the present invention will be described in detail with reference to FIG.

  A three-phase balanced AC voltage is applied to the permanent magnet type three-phase AC motor 1 by an inverter 2 and a three-phase AC current flows.

  The U-phase current iu, V-phase current iv, and W-phase current iw flowing through the permanent magnet type three-phase AC motor 1 are detected by current detectors 31 to 33.

  The three-phase-dq rotational coordinate converter 6 is based on the U-phase current value iu, the V-phase current value iv, the W-phase current value iw and the position information θ from the position detector 7 attached to the permanent magnet type three-phase AC motor 1. The three-phase-dq rotational coordinate conversion is performed based on the equations (5) and (6), and a d-axis current id and a q-axis current iq that can be handled as a DC state on the rotational coordinates are output.

  The d-axis current id and the q-axis current iq are fed back, and the deviation between the d-axis current command idref and the d-axis current id, which is the output of the d-axis current command generator 11, is input to the d-axis current controller 10 and the d-axis voltage. The command Vdref1 is output, the deviation between the q-axis current command iqref and the q-axis current iq, which is the output of the q-axis current command generator 8, is input to the q-axis current controller 9, and the q-axis voltage command Vqref1 is output. .

  The voltage that can be output by the inverter 2 is a function of the inverter DC power supply 4, and the voltage Vmax that can be output by the inverter 2 is expressed by equation (7), where the DC voltage value of the inverter DC power supply 4 is Vdc.

  The limit value Vdlmit of the d-axis voltage command limiter 12 is an equation (8) in which the DC voltage value Vdc of the inverter DC power supply 4 is input, and the d-axis voltage command vdref1 is limited by the d-axis voltage command limiter 12 and d-axis voltage command Vdref2 Is output.

  The limit value Vqlmit of the q-axis voltage command limiter 13 is calculated based on the equation (9) with the d-axis voltage command Vdref2 and the voltage Vmax that can be output by the inverter as inputs. The q-axis voltage command Vqref1 is calculated by the q-axis voltage command limiter 13. The q-axis voltage command Vqref2 is output after being limited.

  When the vector sum of the d-axis voltage command Vdref2 and the q-axis voltage command Vqref1 exceeds the voltage Vmax that can be output from the inverter, a negative d-axis current command idref is generated to perform the flux weakening control.

  The d-axis current command generator 11 receives the q-axis voltage command Vqref1 before the q-axis voltage command limiter 13 and the d-axis voltage command Vdref2 that is the output of the d-axis voltage limiter 12 as inputs from the output of the q-axis current controller 9. In the case of formula (10), the d-axis current command value idref is increased in the negative direction.

  On the other hand, in the case of formula (11), the d-axis current command value is increased in the positive direction.

However, the d-axis current command value is limited to a value of 0 or less.

The q-axis voltage command vqref2 and the d-axis voltage command vdref2 are input to the dq-three-phase rotational coordinate converter 5, and (12) is obtained from the position information θ of the position detector 7 attached to the permanent magnet type three-phase AC motor 1. Based on the equation (13), dq-three-phase coordinate conversion is performed and converted into balanced three-phase AC voltage commands vref, vvref, vwref.

  The inverter 2 applies a three-phase AC voltage based on the three-phase AC voltage commands vref, vvref, and vwref to the permanent magnet type three-phase AC motor 1.

  By applying Claims 1 and 2 of the present invention to a permanent magnet type three-phase AC motor, the maximum q within the voltage range that can be output by the inverter while establishing the flux-weakening control by the d-axis current control. A shaft voltage can be output.

  FIG. 2 shows an embodiment in which claim 3 of the present invention is applied to a permanent magnet type three-phase AC motor, and the present invention will be described in detail based on FIG.

  A deviation between the d-axis current command idref and the d-axis current id from the d-axis current command generator 11 is input to the d-axis current controller 10 and a d-axis voltage command Vdref1 is output. The deviation between the q-axis current command iqref and the q-axis current iq from the q-axis current command generator 8 is input, and the q-axis voltage command Vqref1 is output.

  The d-axis voltage command Vdref1 is limited by the limit value Vdlmit of the d-axis voltage command limiter 12 determined by the mid-line voltage value Vdc of the mid-inverter power supply 4, the d-axis voltage command Vdref2 is output, and the q-axis voltage command Vqref1 is It is limited by the limit value Vqlmit of the q-axis voltage command limiter 13 determined by the intermediate voltage value Vdc of the middle power supply 4 and the d-axis voltage command Vdref2, and the q-axis voltage command Vqref2 is output.

  The d-axis current controller 10 includes a d-axis current control proportional device 101 and a d-axis current control integrator 102. The integrated value of the d-axis current control integrator 102 is limited to the limit value Vdlmit of the d-axis voltage command limiter 12. .

  Similarly, the q-axis current controller 9 includes a q-axis current control proportional unit 91 and a q-axis current control integrator 92, and the integrated value of the q-axis current control integrator 92 is set to the limit value Vqlmit of the q-axis voltage command limiter 13. Restrict.

  By applying Claim 3 of the present invention to a permanent magnet type three-phase AC motor, saturation of the d-axis current control integrator and the q-axis current control integrator can be prevented, and current controllability and responsiveness are improved. it can.

  According to the present invention, it is possible to output more torque while establishing flux-weakening control within the voltage range that the inverter can output, and to improve the controllability and responsiveness of current control. The potential is great.

DESCRIPTION OF SYMBOLS 1 Permanent magnet type three-phase AC motor 2 Inverter 31-33 Current detector 4 Inverter DC power supply
5 dq-three-phase rotational coordinate converter 6 three-phase-dq rotational coordinate converter 7 position detector 8 q-axis current command generator 9 q-axis current controller 10 d-axis current controller 11 d-axis current command generator 12 d Axis voltage command limiter 13 q-axis voltage command limiter 91 q-axis current control proportional device 92 q-axis current control integrator 101 d-axis current control proportional device 102 d-axis current control integrator

Claims (3)

An inverter that applies a voltage based on a three-phase AC voltage command to a permanent magnet type three-phase AC motor, a current detector that detects a three-phase AC current flowing through the permanent magnet type three-phase AC motor, and a three-phase AC current A three-phase-dq rotational coordinate converter that converts a detected value into a d-axis current and a q-axis current, a d-axis current controller that feeds back the d-axis current and controls it to coincide with a d-axis current command value, and the q-axis A q-axis current controller that feeds back current and controls to match the q-axis current command value, a d-axis voltage limiter that limits a d-axis voltage command value that is output from the d-axis current controller, and the q-axis current control The three-phase AC voltage command includes a q-axis voltage limiter that limits a q-axis voltage command value that is an output of the detector, a d-axis voltage command that passes through the d-axis voltage limiter, and a q-axis voltage command that passes through the q-axis voltage limiter. Dq to convert to three-phase rotation coordinates An inverter, the output voltage of the inverter is limited by the voltage value of the DC power supply of the inverter, and when the vector sum of the d-axis voltage command value and the q-axis voltage command value exceeds the limit value, the d-axis A control device for driving the permanent magnet type three-phase AC motor while avoiding output voltage saturation by increasing the d-axis current command value in the negative direction and generating a flux-flux current command by a current command generator In
The d-axis voltage limiter is limited by the maximum output voltage value determined by the voltage value of the DC power supply of the inverter, and the q-axis voltage limiter is the maximum output voltage determined by the voltage value of the DC power supply of the inverter and the d A controller for a permanent magnet type three-phase AC motor, characterized by being limited by a variable limiter calculated from a d-axis voltage command value limited by an axis voltage limiter. 2. The limit value of the d-axis voltage limiter is determined by the equation (1) from the voltage value of the DC power supply of the inverter, and the limit value of the q-axis voltage limiter is a maximum output determined by the voltage value of the DC power supply of the inverter. A control device for a permanent magnet type three-phase AC motor, which is determined by the equation (2) from a voltage and a d-axis voltage command value limited by the d-axis voltage limiter.

  2. The current controller in which the d-axis current controller and the q-axis current controller according to claim 1 are each composed of a proportional unit and an integrator, and the value of the integrator of the d-axis current controller is the d-axis voltage limiter. And the value of the integrator of the q-axis current controller is limited to the q-axis current limiter.

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