POWER CONVERSION SYSTEM FOR ELIMINATING LOW FREQUENCY RIPPLE CURRENT AND CONTROL METHOD THEREOF

• US 20100142236A1
• Filed: 12/07/2009
• Published: 06/10/2010
• Est. Priority Date: 12/09/2008
• Status: Active Grant

• Current Assignee: Intellectual Discovery Co., Ltd.
• Original Assignee: Sungkyunkwan University Foundation For Corporate Collaboration (SungKyunKwan University)
• Inventors: Kim, Jong Soo, Kang, Hyun Soo, Lee, Byoung Kuk, Choe, Gyu Yeong
• Granted Patent: US 8,369,117 B2
• Time in Patent Office: Days
• US Class Current: 363/74
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 1/143 using compensating arrangements for reducing noise from the supply in transmission systems H04B15/005

Abstract

There is provided an integrated control method for eliminating a low frequency ripple in a power conversion system for a fuel cell, more particularly, a control method of a power conversion system capable of eliminating a low frequency ripple, controlling a DC link voltage, and controlling an output power and a system using the same control method. A power conversion system (PCS) that converts an output of a DC power supply received from an external power supply includes a converter that converts a voltage of the input power supply; an inverter that converts an output voltage of the converter into an AC voltage; and a converter control module that outputs a PWM signal for controlling a switch of the converter, and after receiving a power instruction value, the converter control module generates the PWM signal for controlling the converter based on the power instruction value.

Claims

1. A power conversion system (PCS) that converts an output of a DC power supply received from an external power supply, the power conversion system comprising:

a converter that converts a voltage of the input power supply;

an inverter that converts an output voltage of the converter into an AC voltage; and

a converter control module that outputs a PWM signal for controlling a switch of the converter,

wherein after receiving a power instruction value, the converter control module generates the PWM signal for controlling the converter based on the power instruction value.

2. The power conversion system of claim 1, further comprising:

a first sensor module that measures a voltage value and a current value,

wherein the converter control module calculates a current instruction value by using the inputted power instruction value and the voltage value measured by the first sensor module, and generates the PWM signal for controlling the switch of the converter based on an error value between the current instruction value and the current value measured by the first sensor module.

3. The power conversion system of claim 1, further comprising:

an inverter control module that outputs a PWM signal for controlling a switch of the inverter,

wherein after receiving a voltage instruction value, the inverter control module generates a current instruction value based on the voltage instruction value and generates the PWM signal for controlling the inverter based on the generated current instruction value.

4. The power conversion system of claim 3, further comprising:

a second sensor module that measures a output voltage value of the converter and a third sensor module that measures a output current value of the inverter,

wherein the inverter control module controls an error value between the inputted voltage instruction value and the voltage value measured by the second sensor module to be zero and calculates a first current instruction value based on the error value,

obtains a feed-forward term by dividing the power instruction value received from the converter control module by a load voltage value and multiplies the feed-forward term by an estimation phase of a general electric power system, thereby obtaining a second current instruction value, and

generates the PWM signal for controlling the switch of the inverter based on an error value between a third current instruction value obtained by adding the first current instruction value to the second current instruction value and the current value measured by the third sensor module.

5. The power conversion system of claim 2, wherein the first sensor module is installed between a fuel cell and the converter,

the measured voltage value and current value serve as a converter input voltage value and a converter input current value, respectively, and

the current instruction value serves as a converter input current instruction value.

6. The power conversion system of claim 2, wherein the first sensor module is installed between the converter and the inverter,

the measured voltage value and current value serve a DC link voltage value and a DC link current value, respectively, and

the current instruction value serves as a DC link current instruction value.

7. The power conversion system of claim 4, wherein a voltage value measured by the second sensor module serve as a DC link voltage value, and

a voltage value measured by the third sensor module serve as a inverter output current value.

8. The power conversion system of claim 1, wherein the external power supply is a fuel cell.

9. The power conversion system of claim 1, wherein the converter takes any one of various forms such as a boost-type converter, a boost converter, a half-bridge converter, a full-bridge converter, and a push-pull converter so as to boost a low DC voltage to a DC voltage having a predetermined voltage level.

10. A control method of a power conversion system (PCS) including a converter that converts a voltage of an input power supply, and an inverter that converts an output voltage of the converter into a AC voltage, the control method comprising:

receiving a power instruction value; and

generating a PWM signal for controlling the converter based on the received power instruction value.

11. The control method of claim 10, wherein the step of generating the PWM signal for controlling the converter includes:

measuring a voltage value and a current value for controlling the converter;

calculating a current instruction value by using the inputted power instruction value and the measured current value; and

generating a PWM signal for controlling a switch of the converter based on an error value between the current instruction value and the measured current value.

12. The control method of claim 10, further comprising:

receiving a voltage instruction value; and

generating a PWM signal for controlling the inverter based on the voltage instruction value and the current instruction value which is calculated using the voltage instruction value.

13. The control method of claim 12, wherein the step of generating the PWM signal for controlling the inverter includes:

measuring a voltage value and a current value for controlling the inverter;

calculating a first current instruction value for allowing an error value between the inputted voltage instruction value and the measured voltage value to be zero;

obtaining a feed-forward term by dividing the inputted power instruction value by a load voltage value, and multiplying the feed-forward term by a estimation phase of a general electric power system, thereby obtaining a second current instruction value, and

generating the PWM signal for controlling the switch of the inverter based on an error value between a third current instruction value obtained by adding the first current instruction value to the second current instruction value and the measured current value.

14. The control method of claim 11, wherein the measured voltage value and current value serve as a converter input voltage value and a converter input current value, respectively, and

the current instruction value serves as a converter input current instruction value.

15. The control method of claim 11, wherein the measured voltage value and current value serve as a DC link voltage value and a DC link current value, respectively, and

the current instruction value serves as a DC link current instruction value.

16. The control method of claim 12, wherein the measured voltage value serves as a DC link voltage value, and the measured current value serves as an inverter output current value.

17. A program stored in a computer-readable storage medium that executes a control method of a power conversion system (PCS) including a converter for converting a voltage of an input power supply, and an inverter for converting an output voltage of the converter into an AC voltage, the program comprising:

receiving a power instruction value; and

generating a PWM signal for controlling the converter based on the received power instruction value.

18. The program of claim 17, wherein the step of generating the PWM signal for controlling the converter includes:

measuring a voltage value and a current value for controlling the converter;

calculating a current instruction value by using the received power instruction value and the measured current value; and

generating a PWM signal for controlling a switch of the converter based on an error value between the current instruction value and the measured current value.

19. The program of claim 17, further comprising:

receiving a voltage instruction value; and

generating a PWM signal for controlling the inverter based on the voltage instruction value and the power instruction value.