Power conversion device

Patent metadata

Field	Value
Publication number	US-12113450-B2
Application number	US-202217679084-A
Country	US
Kind code	B2
Filing date	Feb 24, 2022
Priority date	Feb 26, 2021
Publication date	Oct 8, 2024
Grant date	Oct 8, 2024

Abstract

The power conversion device may include: power conversion circuitry configured to perform a power conversion for outputting a driving power to an induction motor; and control circuitry. The control circuitry may be configured to: receive a master command phase from a master power conversion device; generate a voltage command having a command phase in a rotating coordinate system based on a torque target value, wherein a rotating magnetic field for driving a rotor of the induction motor is generated to rotate with the rotating coordinate system; calculate a rotation phase of the rotating coordinate system based on a command phase difference between the master command phase and the command phase to reduce the command phase difference; and control the power conversion circuitry to output the driving power to the induction motor, in synchronization with the master power conversion device, based on the rotation phase and the voltage command.

First claim

What is claimed is:

1. A power conversion device comprising:
power conversion circuitry configured to perform a power conversion for outputting a driving power to an induction motor;
a communication interface configured to receive one or more signals from a master power conversion device; and
control circuitry configured to:
receive a master command phase from the communication interface based, at least in part, on the one or more signals from the master power conversion device;
generate a voltage command having a command phase in a rotating coordinate system based on a torque target value, wherein a rotating magnetic field for driving a rotor of the induction motor is generated to rotate with the rotating coordinate system;
calculate a rotation phase of the rotating coordinate system based on a command phase difference between the master command phase and the command phase to reduce the command phase difference; and
control the power conversion circuitry to output the driving power to the induction motor, based on the rotation phase and the voltage command, so that the rotating magnetic field is in synchronization with a master rotating magnetic field generated by the master power conversion device.

2. The power conversion device according to claim 1 , wherein the communication interface is further configured to receive one or more second signals from the master power conversion device, and
wherein the control circuitry is further configured to:
receive a master rotation phase from the communication interface based, at least in part, on the one or more second signals from the master power conversion device;
calculate the rotation phase based on a rotation phase difference between the master rotation phase and the rotation phase to reduce the rotation phase difference if a coordinate rotation speed of the rotating coordinate system is less than a first threshold; and
calculate the rotation phase based on the command phase difference if the coordinate rotation speed is greater than a second threshold that is equal to or higher than the first threshold.

3. The power conversion device according to claim 2 , wherein the control circuitry is further configured to:
calculate the rotation phase based on a weighted average value of the command phase difference and the rotation phase difference if the coordinate rotation speed is between the first threshold and the second threshold; and
gradually decrease a weight of the rotation phase difference and gradually increase a weight of the command phase difference as the coordinate rotation speed approaches the second threshold from the first threshold.

4. The power conversion device according to claim 2 , wherein the control circuitry is further configured to:
calculate the rotation phase based on a torque target value, a rotor speed of the induction motor, and the rotation phase difference if the coordinate rotation speed is less than the first threshold; and
calculate the rotation phase based on the torque target value, the rotor speed, and the command phase difference if the coordinate rotation speed is greater than the second threshold.

5. The power conversion device according to claim 4 , wherein the control circuitry is further configured to:
calculate an angular frequency command value of the rotating coordinate system based on the torque target value and the rotor speed;
correct the angular frequency command value based on the rotation phase difference if the coordinate rotation speed is less than the first threshold;
correct the angular frequency command value based on the command phase difference if the coordinate rotation speed is greater than the second threshold; and
calculate the rotation phase by integrating the corrected angular frequency command value.

6. The power conversion device according to claim 2 ,
wherein the one or more second signals received from the master power conversion device comprise a sine value of the master rotation phase and a cosine value of the master rotation phase, and
wherein the control circuitry is further configured to calculate the rotation phase based on the sine value and the cosine value if the coordinate rotation speed is less than the first threshold.

7. The power conversion device according to claim 6 , wherein the control circuitry is further configured to detect an abnormality of a communication for receiving the sine value and the cosine value based on a square sum of the sine value and the cosine value.

8. The power conversion device according to claim 7 , wherein the control circuitry is further configured to detect an abnormality of a second communication for receiving the master command phase if the master command phase is smaller than a predetermined level.

9. The power conversion device according to claim 2 , wherein the communication interface is further configured to receive one or more third signals from the master power conversion device, and
wherein the control circuitry is further configured to:
receive a master torque target value from the communication interface based, at least in part, on the one or more third signals from the master power conversion device;
calculate the torque target value based on the master torque target value; and
generate the voltage command based on the calculated torque target value.

10. The power conversion device according to claim 7 , wherein the control circuitry is further configured to:
detect an abnormality of the communication interface a based on the rotation phase difference if the coordinate rotation speed is less than the first threshold; and
detect the abnormality of the communication based on the command phase difference if the coordinate rotation speed is greater than the second threshold.

11. The power conversion device according to claim 1 , wherein the power conversion circuitry is a matrix converter circuitry configured to perform bidirectional AC-AC power conversion.

12. The power conversion device according to claim 1 , wherein the control circuitry is further configured to calculate the rotation phase based on the torque target value, a rotor speed of the induction motor, and the command phase difference.

13. The power conversion device according to claim 12 , wherein the control circuitry is further configured to:
calculate an angular frequency command value of the rotating coordinate system based on the torque target value and the rotor speed of the induction motor;
correct the angular frequency command value based on the command phase difference to reduce the command phase difference; and
calculate the rotation phase by integrating the corrected angular frequency command value.

14. A power conversion device according to claim 1 , wherein the power conversion device is configured to operate as the master power conversion device in a first mode, or as a second power conversion device in a second mode, based on a mode selection input,
wherein the control circuitry, in the first mode, is configured to:
generate a master voltage command having the master command phase in a master rotating coordinate system that rotates with the rotor; and
control the power conversion circuitry to output a master driving power to the induction motor based on the master voltage command, and

wherein the control circuitry, in the second mode, is configured to:
generate the voltage command based on the torque target value;
calculate the rotation phase based on the command phase difference to reduce the command phase difference; and
control the power conversion circuitry to output the driving power to the induction motor based on the rotation phase and th

Assignees

• Yaskawa Electric Corp

Inventors

• Inoki Keisei
• Saeki Takahiro
• Hanada Toshihiro
• Nakahara Kengo
• Iura Hideaki

Classifications

• H02P29/028

  the motor continuing operation despite the fault condition, e.g. eliminating, compensating for or remedying the fault · CPC title

• H02P1/26

  for starting an individual polyphase induction motor · CPC title

• H02P27/04

  using variable-frequency supply voltage, e.g. inverter or converter supply voltage · CPC title

• H02P21/22

  Current control, e.g. using a current control loop · CPC title

• H02P2207/01

  Asynchronous machines · CPC title