Systems and methods for a variable frequency multiplier power converter

• US 9,853,550 B2
• Filed: 10/31/2013
• Issued: 12/26/2017
• Est. Priority Date: 10/31/2012
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Perreault, David J., Afridi, Khurram K., Gunter, Samantha J.
• Primary Examiner(s): Laxton, Gary L
• Application Number:
  US14/435,914
• Publication Number:
  US 20150295497A1
• Time in Patent Office: 1,517 Days
• CPC Class Codes: H02M 1/0048 Circuits or arrangements for reducing losses using snubbers H02M1/34
• CPC Class Codes: H02M 1/0054 Transistor switching losses periodically suspending operation of switching converter in low power mode H02M1/0035
• CPC Class Codes: H02M 1/0058 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 Class Codes: H02M 1/0074 Plural converter units whose inputs are connected in series
• CPC Class Codes: H02M 1/0077 Plural converter units whose outputs are connected in series
• CPC Class Codes: H02M 1/4241 using a resonant converter
• CPC Class Codes: H02M 1/44 Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
• CPC Class Codes: H02M 3/07 using capacitors charged and discharged alternately by semiconductor devices with control electrode , e.g. charge pumps
• CPC Class Codes: H02M 3/33507 with automatic control of the output voltage or current, e.g. flyback converters H02M3/33561, H02M3/33569 take precedence
• CPC Class Codes: H02M 3/33523 with galvanic isolation between input and output of both the power stage and the feedback loop
• CPC Class Codes: H02M 3/3376 with automatic control of output voltage or current
• CPC Class Codes: H02M 7/217 using semiconductor devices only
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

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.

Claims

1. A power converter comprising:

an inverter stage having two or more switched inverters each configured to receive a first input from a source and produce a switched AC output power signal at a corresponding output thereof;

two or more transformation stages each coupled to receive a switched output power signal from a corresponding output of said two or more switched inverters of said inverter stage, shape the switched output power signal, and produce a shaped power signal, said two or more transformation stages having a fundamental frequency of operation;

a rectifier stage having two or more switched inverters coupled to receive a shaped power signal from said two or more transformation stages and convert the shaped power signal to a DC output power signal; and

a controller circuit coupled to operate the power converter in a variable frequency multiplier mode.

2. The power converter of claim 1 wherein said controller circuit operates the power converter in a variable frequency multiplier mode by operating at least one of said inverter stage and said rectifier stage at a switching frequency corresponding to one of a fundamental of the transformation stages frequency of operation or a harmonic of the transformation stages frequency of operation.

3. The power converter of claim 1 wherein operating at least one of said inverter stage and said rectifier stage at a switching frequency corresponding to one of a fundamental or a harmonic of the transformation stages frequency of operation comprises operating at least one of said inverter stage and said rectifier stage at one of:

a frequency which is less than a fundamental of the transformation stages frequency;

or

a frequency which is greater than a fundamental of the transformation stages frequency.

4. The power converter of claim 1 wherein said inverter stage comprises a stacked inverter.

5. The power converter of claim 1 wherein at least some of said two or more switched inverters of said inverter stage are configured to be operated in different modes.

6. The power converter claim 1 wherein said two or more transformation stages are configured to shape an output power signal by one or more of:

performing a voltage level transformation;

performing a waveform shaping operation;

or

providing electrical isolation.

7. The power converter of claim 1 wherein said controller circuit is configured to drive one or both of said inverter stage and said rectifier stage in a variable frequency multiplier mode.

8. The power converter of claim 1 wherein said controller circuit is configured to operate the power converter in variable frequency multiplier mode by operating at least one of said inverter stage and said rectifier stage in a variable frequency multiplier mode, or by operating both of said inverter stage and said rectifier stage in a variable frequency multiplier mode.

9. The power converter of claim 1 wherein said controller circuit is configured to operate one or more of said two or more switched inverters of said inverter stage at a frequency corresponding to a fundamental frequency of said transformation stages frequency of operation mode and one or more of said two or more switched inverters of said inverter stage at a frequency corresponding to a variable frequency multiplier mode.

10. The power converter of any of claim 1 wherein said controller circuit is configured to operate one or more of said switched inverters of said inverter stage in a fundamental mode while operating one or more of said switched inverters of said rectifier stage in a variable frequency multiplier mode.

11. The power converter of claim 1 wherein said controller circuit is configured to operate the power converter in the variable frequency multiplier mode by switching at least one of said two or more switched inverters of said rectifier stage at a frequency that is a multiple of the fundamental frequency of said transformation stages.

12. The power converter of claim 1 wherein said controller circuit is configured to operate the power converter in the variable frequency multiplier mode by switching at least one of said two or more switched inverters of said inverter stage at a duty cycle that reinforces a harmonic of the operating frequency at the inverter output.

13. The power converter of claim 1 wherein said controller circuit is configured to operate the power converter in the variable frequency multiplier mode by one or more of:

adding a time delay between switching of said two or more switched inverters in said inverter stage; and

adding a time delay between switching one or more switched inverters in said rectifier stage.

14. The power converter of claim 1 wherein said controller circuit operates at least one of said two or more switched inverters in said inverter stage at a fundamental frequency that is one-half of a desired output frequency to achieve a frequency doubler mode of operation.

15. The power converter of claim 1 wherein said controller circuit is configured to operate at least one of said inverter stage and said rectifier stage at a switching frequency corresponding to one of a fundamental or a harmonic of the transformation stages frequency of operation such that a switching frequency and duty ratio of switching elements in at least one of said inverter stage and said rectifier stage change without altering a frequency at which power is transferred through said transformation stages.

16. The power converter of claim 1 wherein said controller circuit is configured to operate the power converter in variable frequency multiplier mode by operating both of said inverter stage and said rectifier stage in a variable frequency multiplier mode.

17. The power converter of claim 16 wherein said controller is configured to operate said rectifier stage at one of:

a frequency which is less than a fundamental of the transformation stages frequency;

or

a frequency which is greater than a fundamental of the transformation stages frequency.