Systems and Methods for a Variable Frequency Multiplier Power Converter

Patent metadata

Field	Value
Publication number	US-2016254754-A1
Application number	US-201615149491-A
Country	US
Kind code	A1
Filing date	May 9, 2016
Priority date	Oct 31, 2012
Publication date	Sep 1, 2016
Grant date	—

Abstract

A power converter for converting DC power to DC power includes an inverter stage having two or more switched inverters configured to receive DC power from a source and produce a switched AC output power signal. A transformation stage is coupled to receive the switched output power signal from the inverter stage, shape the output power signal, and produce a shaped power signal. A rectifier stage having two or more switched inverters coupled to receive the shaped power signal and convert the shaped power signal to a DC output power signal is included. A controller circuit is coupled to operate the power converter in a variable frequency multiplier mode where at least one of the switched inverters is switched at a frequency or duty cycle that results in an output signal having a frequency that is a harmonic of the fundamental frequency being generated by the power converter.

First claim

What is claimed is:

1 . A power converter comprising:
an inverter stage having a plurality of switched inverters configured to receive a power input and produce an AC voltage based on the power input; a transformation stage coupled to receive the AC voltage; a rectifier coupled to receive a signal from the transformation stage; and a controller configured to control switching of the plurality of switched inverters and configured to change a magnitude of the AC voltage by varying the switching of the plurality of switched inverters.

2 . The power converter of claim 1 , wherein the controller is configured to control the inverter stage in a mode of operation in which the magnitude of the AC voltage is reduced by a factor of two.

3 . The power converter of claim 1 , wherein the controller is configured to vary the switching of the plurality of switched inverters based on the power input.

4 . The power converter of claim 1 , wherein the power converter is an LLC converter, a series-resonant converter or a parallel-resonant converter.

5 . The power converter of claim 1 , wherein the controller is configured to vary a switching frequency of the plurality of switched inverters.

6 . The power converter of claim 5 , wherein the controller is configured to vary a switching frequency of the plurality of switched inverters by an integer multiple.

7 . The power converter of claim 1 , wherein the controller is configured to vary a duty ratio of the plurality of switched inverters.

8 . The power converter of claim 7 , wherein the controller is configured to vary a switching frequency of the plurality of switched inverters.

9 . The power converter of claim 8 , wherein the controller is configured to reduce the magnitude of the AC voltage by a factor of two by reducing the switching frequency by a factor of two and varying the duty ratio of the plurality of switched inverters.

10 . The power converter of claim 9 , wherein the plurality of switched inverters comprises a first switched inverter and a second switched inverter, and wherein the AC voltage is reduced by a factor of two at least in part by controlling the first switched inverter to have a duty ratio of 0.25 and controlling the second switched inverter to have a duty ratio of 0.75.

11 . The power converter of claim 10 , wherein the controller is configured to reduce the magnitude of the AC voltage by a factor of two by switching the first switched inverter and the second switched inverter in-phase with one another.

12 . The power converter of claim 9 , wherein a frequency of the AC voltage is a harmonic of the switching frequency of the plurality of switched inverters.

13 . The power converter of claim 1 , wherein the plurality of switched inverters comprises stacked inverters.

14 . A power converter comprising:
an inverter stage having a plurality of switched inverters configured to receive a power input and produce an AC voltage based on the power input; a transformation stage coupled to receive the AC voltage; a rectifier coupled to receive a signal from the transformation stage; and a controller configured to operate the inverter stage in a variable frequency multiplier mode.

15 . The power converter of claim 14 , wherein, when the inverter stage is operated in the variable frequency multiplier mode, the magnitude of the AC voltage is reduced by a factor of two.

16 . The power converter of claim 15 , wherein, when the inverter stage is operated in the variable frequency multiplier mode, a switching frequency of the plurality of switched inverters is reduced by a factor of two.

17 . The power converter of claim 16 , wherein, when the inverter stage is operated in the variable frequency multiplier mode, a duty ratio of at least one switched inverter of the plurality of switched inverters is modified.

18 . The power converter of claim 16 , wherein the plurality of switched inverters comprises a first switched inverter and a second switched inverter, wherein, when the inverter stage is operated in the variable frequency multiplier mode, the first switched inverter is controlled to have a duty ratio of 0.25 and the second switched inverter is controlled to have a duty ratio of 0.75.

19 . The power converter of claim 18 , wherein, when the inverter stage is operated in the variable frequency multiplier mode, the first switched inverter and the second switched inverter are switched in-phase with one another.

20 . The power converter of claim 14 , wherein, when the inverter stage is operated in the variable frequency multiplier mode, a frequency of the AC voltage is a harmonic of a switching frequency of the plurality of switched inverters.

21 . The power converter of claim 14 , wherein the power converter is an LLC converter, a series-resonant converter or a parallel-resonant converter.

22 . A method of operating a power converter, the power converter including an inverter stage having a plurality of switched inverters configured to receive a power input and produce an AC voltage based on the power input, a transformation stage coupled to receive the AC voltage, and a rectifier coupled to receive a signal from the transformation stage, the method comprising:
controlling switching of the plurality of switched inverters; and changing a magnitude of the AC voltage by varying the switching of the plurality of switched inverters.

23 . The method of claim 22 , wherein changing the magnitude of the AC voltage comprises reducing a magnitude of the AC voltage by a factor of two.

24 . The method of claim 23 , wherein the magnitude of the AC voltage is reduced by a factor of two by reducing a switching frequency of the plurality of switched inverters by a factor of two and varying a duty ratio of at least one switched inverter of the plurality of switched inverters.

Assignees

• Massachusetts Inst Technology

Inventors

• Perreault David J
• Afridi Khurram K
• Gunter Samantha J

Classifications

• H02M3/33507 Primary

  with automatic control of the output voltage or current, e.g. flyback converters (H02M3/33561, H02M3/33569 take precedence) · CPC title

• H02M1/4241

  using a resonant converter · CPC title

• H02M1/44

  Circuits or arrangements for compensating for electromagnetic interference in converters or inverters · CPC title

• H02M1/0058

  by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero (using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826) · CPC title

• H02M1/0054

  Transistor switching losses (periodically suspending operation of switching converter in low power mode H02M1/0035) · CPC title