Power conversion system and control method for voltage conversion circuit

Patent metadata

Field	Value
Publication number	US-11239760-B2
Application number	US-201917041248-A
Country	US
Kind code	B2
Filing date	Mar 25, 2019
Priority date	Mar 29, 2018
Publication date	Feb 1, 2022
Grant date	Feb 1, 2022

Abstract

A power conversion system converts an input alternating-current voltage having a first frequency into an output alternating-current voltage having a second frequency lower than the first frequency. The power conversion system includes a voltage converter, a PDM controller, and a feedback controller. The voltage converter converts the input alternating-current voltage into the output alternating-current voltage in accordance with control signals and outputs the output alternating-current voltage to a load. The PDM controller performs pulse density modulation of an output voltage command value of the output alternating-current voltage to generate the control signals and outputs the control signals to the voltage converter. The feedback controller generates the output voltage command value based on an output current value of the voltage converter and a state of the load and outputs the output voltage command value to the PDM controller.

First claim

The invention claimed is:

1. A power conversion system configured to convert an input alternating-current voltage having a first frequency into an output alternating-current voltage having a second frequency lower than the first frequency, the power conversion system comprising:
a voltage converter configured to
convert the input alternating-current voltage into the output alternating-current voltage in accordance with a control signal and
output the output alternating-current voltage to a load;

a PDM controller configured to
perform pulse density modulation of an output voltage command value of the output alternating-current voltage to generate a modulation signal,
generate the control signal in accordance with the modulation signal, a polarity of the input alternating-current voltage, and a polarity of the output voltage command value, and
output the control signal to the voltage converter; and

a feedback controller configured to
generate the output voltage command value based on an output current value of the voltage converter and a state of the load and
output the output voltage command value to the PDM controller.

2. The power conversion system of claim 1 , wherein
the PDM controller is configured to generate the modulation signal in synchrony with a timing at which the input alternating-current voltage is zero.

3. The power conversion system of claim 2 , wherein
the feedback controller is configured to generate, based on vector control, the output voltage command value.

4. The power conversion system of claim 3 , wherein
the input alternating-current voltage has a single phase, and
the output alternating-current voltage has three phases.

5. The power conversion system of claim 4 , wherein
the load is a synchronous motor.

6. The power conversion system of claim 3 , wherein
the load is a synchronous motor.

7. The power conversion system of claim 2 , wherein
the input alternating-current voltage has a single phase, and
the output alternating-current voltage has three phases.

8. The power conversion system of claim 7 , wherein
the load is a synchronous motor.

9. The power conversion system of claim 2 , wherein
the load is a synchronous motor.

10. The power conversion system of claim 1 , wherein
the feedback controller is configured to generate, based on vector control, the output voltage command value.

11. The power conversion system of claim 10 , wherein
the input alternating-current voltage has a single phase, and
the output alternating-current voltage has three phases.

12. The power conversion system of claim 11 , wherein
the load is a synchronous motor.

13. The power conversion system of claim 10 , wherein
the load is a synchronous motor.

14. The power conversion system of claim 1 , wherein
the input alternating-current voltage has a single phase, and
the output alternating-current voltage has three phases.

15. The power conversion system of claim 14 , wherein
the load is a synchronous motor.

16. The power conversion system of claim 1 , wherein
the load is a synchronous motor.

17. The power conversion system of claim 1 , wherein
the input alternating-current voltage is input by wireless power supply.

18. The power conversion system of claim 1 , wherein
the voltage converter is a matrix converter having a plurality of bidirectional switches.

19. The power conversion system of claim 1 , wherein
a digit number of the first frequency is larger than a digit number of the second frequency by three or more digits.

20. A control method for a voltage conversion circuit configured to convert an input alternating-current voltage having a first frequency into an output alternating-current voltage having a second frequency lower than the first frequency in accordance with a control signal and output the output alternating-current voltage to a load, the control method comprising:
a PDM control step of performing pulse density modulation of an output voltage command value of the output alternating-current voltage to generate a modulation signal and generating the control signal in accordance with the modulation signal, a polarity of the input alternating-current voltage, and a polarity of the output voltage command value; and
a feedback control step of generating the output voltage command value based on an output current value supplied to the load and a state of the load.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Kudoh Yuji

Classifications

• H02M5/14

  for conversion between circuits of different phase number · CPC title

• H02P2201/01

  AC-AC converter stage controlled to provide a defined AC voltage · CPC title

• H02M7/4807 Primary

  having a high frequency intermediate AC stage · CPC title

• H02P21/22

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

• H02M5/2932

  with automatic control of output voltage, current or power · CPC title