POWER CONVERTER AND POWER CONVERSION METHOD

• US 20140293658A1
• Filed: 03/27/2014
• Published: 10/02/2014
• Est. Priority Date: 03/29/2013
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: CAO, Yu, WANG, Kezhi
• Granted Patent: US 9,667,161 B2
• Time in Patent Office: Days
• US Class Current: 363/21.02
• CPC Class Codes: H02M 1/0022 the disturbance parameters being input voltage fluctuations
• CPC Class Codes: H02M 3/33576 having at least one active switching element at the secondary side of an isolation transformer

Abstract

A power converter includes a switching circuit, a power conversion circuit that receives an input voltage via the switching circuit and converts the input voltage into an output voltage, an input voltage sense circuit that detects the input voltage and generates an input voltage sense signal, and a PWM controller that adjusts a duty cycle of the switching circuit based at least in part on the input voltage sense signal. The power converter also includes an output sense circuit that detects the output voltage and generates an output voltage sense signal, wherein the PWM controller adjusts the duty cycle of the switching circuit based at least in part on the input voltage sense signal and the output voltage sense signal.

Claims

1. A power converter, comprising:

a switching circuit;

a power conversion circuit configured to receive an input voltage via the switching circuit and convert the input voltage into an output voltage;

an input voltage sense circuit configured to detect the input voltage and generate an input voltage sense signal; and

a PWM controller configured and programmed to adjust a duty cycle of the switching circuit based at least in part on the input voltage sense signal provided by the input voltage sense circuit.

2. The power converter of claim 1, wherein if the input voltage sense signal indicates a change in the input voltage, the PWM controller adjusts the duty cycle of the switching circuit within a preset range such that a change rate of the output voltage is lower than a change rate of the input voltage.

3. The power converter of claim 1, further comprising:

an output sense circuit configured to detect the output voltage and generate an output voltage sense signal;

wherein

the PWM controller is configured and programmed to adjust the duty cycle of the switching circuit based at least in part on the input voltage sense signal and the output voltage sense signal.

4. The power converter of claim 3, further comprising:

a reference voltage module configured to generate a reference voltage based on the input voltage sense signal provided by the input voltage sense circuit such that the reference voltage is proportional to the input voltage; and

a first operational amplifier configured to generate a first comparison signal based on a difference between the output voltage sense signal and the reference voltage, the first comparison signal being provided to the PWM controller as a feedback signal;

wherein

the PWM controller adjusts the duty cycle of the switching circuit within a preset range according to the feedback signal such that the output voltage is maintained on a level proportional to the reference voltage.

5. The power converter of claim 4, wherein

the output sense circuit further detects an output current and generates an output current sense signal;

and

the power converter further comprises;

a second operational amplifier configured to generate a second comparison signal based on a difference between the output current sense signal and the first comparison signal, the second comparison signal being provided to the PWM controller as the feedback signal.

6. The power converter of claim 3, wherein

if the input voltage changes, the output voltage varies along with the input voltage;

and

if the input voltage does not change, the PWM controller adjusts the duty cycle of the switching circuit within a preset range such that the output voltage remains unchanged.

7. The power converter of claim 1, wherein the power converter is an isolated power converter, and includes an isolator to transfer signals in an isolated manner between a primary side and a secondary side of the power converter.

8. A method for controlling a power converter, comprising:

receiving an input voltage via a switching circuit and converting the input voltage into an output voltage;

detecting the input voltage and generating an input voltage sense signal; and

adjusting a duty cycle of the switching circuit based at least in part on the input voltage sense signal.

9. The method of claim 8, further comprising if the input voltage sense signal indicates a change in the input voltage, adjusting the duty cycle of the switching circuit within a preset range such that a change rate of the output voltage is lower than a change rate of the input voltage.

10. The method of claim 8, further comprising:

detecting the output voltage and generating an output voltage sense signal; and

adjusting the duty cycle of the switching circuit based at least in part on the input voltage sense signal and the output voltage sense signal.

11. The method of claim 10, further comprising:

generating a reference voltage based on the input voltage sense signal such that the reference voltage is proportional to the input voltage;

generating a first comparison signal based on a difference between the output voltage sense signal and the reference voltage as a feedback signal; and

adjusting the duty cycle of the switching circuit within a preset range according to the feedback signal such that the output voltage is maintained on a level proportional to the reference voltage.

12. The method of claim 11, further comprising:

detecting an output current and generating an output current sense signal; and

generating a second comparison signal based on a difference between the output current sense signal and the first comparison signal as the feedback signal.

13. The method of claim 10, wherein:

if the input voltage changes, the output voltage varies along with the input voltage; and

if the input voltage does not change, the duty cycle of the switching circuit is adjusted within a preset range such that the output voltage remains unchanged.

14. The method of claim 8, wherein

the power converter is an isolated power converter;

and

the method further comprises;

transferring signals in an isolated manner between a primary side and a secondary side of the power converter.

15. A power converter, comprising:

means for receiving an input voltage via a switching circuit and converting the input voltage into an output voltage;

means for detecting the input voltage and generating an input voltage sense signal; and

means for adjusting a duty cycle of the switching circuit based at least in part on the input voltage sense signal.

16. The power converter of claim 15, further comprising means for adjusting the duty cycle of the switching circuit within a preset range if the input voltage sense signal indicates a change in the input voltage such that a change rate of the output voltage is lower than a change rate of the input voltage.

17. The power converter of claim 15, further comprising:

means for detecting the output voltage and generating an output voltage sense signal; and

means for adjusting the duty cycle of the switching circuit based at least in part on the input voltage sense signal and the output voltage sense signal.

18. The power converter of claim 17, further comprising:

means for generating a reference voltage based on the input voltage sense signal such that the reference voltage is proportional to the input voltage;

means for generating a first comparison signal based on a difference between the output voltage sense signal and the reference voltage as a feedback signal; and

means for adjusting the duty cycle of the switching circuit within a preset range according to the feedback signal such that the output voltage is maintained on a level proportional to the reference voltage.

19. The power converter of claim 18, further comprising:

means for detecting an output current and generating an output current sense signal; and

means for generating a second comparison signal based on a difference between the output current sense signal and the first comparison signal as the feedback signal.

20. The power converter of claim 17, wherein:

if the input voltage changes, the output voltage varies along with the input voltage; and

if the input voltage does not change, the duty cycle of the switching circuit is adjusted within a preset range such that the output voltage remains unchanged.

21. The power converter of claim 15, wherein

the power converter is an isolated power converter;

and

the power converter further comprises;

means for transferring signals in an isolated manner between a primary side and a secondary side of the power converter.