DC-DC converter and bi-directional DC-DC converter and method of controlling the same

• US 6,574,125 B2
• Filed: 01/23/2002
• Issued: 06/03/2003
• Est. Priority Date: 01/24/2001
• Status: Expired due to Fees

• Current Assignee: Nissin Electric Company Limited
• Original Assignee: Nissin Electric Company Limited
• Inventors: Nakagaki, Hitoshi, Matsukawa, Mitsuru, Hasebe, Takaya, Kurio, Nobuhiro
• Primary Examiner(s): Sherry, Michael
• Assistant Examiner(s): Laxton, Gary L.
• Application Number:
  US10/052,414
• Publication Number:
  US 20020126517A1
• Time in Patent Office: 496 Days
• Field of Search: 363/17, 363/65, 363/71, 363/98, 363/132, 363/70
• US Class Current: 363/71
• CPC Class Codes: H02M 1/0074 Plural converter units whose inputs are connected in series
• CPC Class Codes: H02M 3/33571 Half-bridge at primary side of an isolation transformer
• CPC Class Codes: H02M 3/33573 Full-bridge at primary side of an isolation transformer
• CPC Class Codes: H02M 3/33584 Bidirectional converters

Abstract

A DC—DC converter has converter circuit portions 11 and 12, transformers Tr₁ and Tr₂, and rectifier circuit portions 21 and 22. Two sets of converter circuit portions 11 and 12 respectively include two pairs of switching elements Q₁ to Q₄, and two pairs of switching elements Q₅ to Q₈ connected in full bridge configuration, series capacitors C₁ and C₂ are inserted and connected between the converter circuit portions 11 and 12 and the transformers Tr₁ and Tr₂ respectively. The switching phase of one switching element Q₄ or Q₈ is shifted by a 1/3n period from the switching phase of the other switching element Q₁ or Q₅ in the pair of switching elements. The switching phases of corresponding switching elements Q₁ and Q₅ in the converter circuit portions 11 and 12 are shifted by a 1/2n period from each other.

Claims

1. A DC—

DC converter comprising;

n sets of converter circuit portions for converting a power source voltage of a DC power supply into AC voltages, each of which includes two pairs of switching elements connected in full bridge configuration;

transformers connected to output sides of the converter circuit portions; and

rectifier circuit portions connected to said converter circuit portions through the transformers respectively,

wherein a switching phase of one switching element in each pair of switching elements included in each converter circuit portion is shifted by a 1/3n period from a switching phase of the other switching element in said pair of switching elements, and switching phases of corresponding switching elements in said converter circuit portions are shifted by a 1/2n period from one another.

2. The DC—

DC converter according to claim 1, further comprising;

series capacitors inserted and connected between said converter circuit portions and said transformers respectively.

3. The DC—

DC converter according to claim 1, wherein said n sets of converter circuit portions are connected in series to said DC power source.

4. The DC—

DC converter according to claim 3, wherein each of said switching elements includes an MOS-FET.

5. The DC—

DC converter according to claim 1, wherein one switching element in each pair of switching elements included in each converter circuit portion is replaced by a capacitor to thereby form said converter circuit portion into half bridge configuration.

6. The DC—

DC converter according to claim 1, wherein said n sets of converter circuit portions are connected in parallel to said DC power source.

7. The DC—

DC converter according to claim 1, further comprising;

a voltage detecting unit provided on an output side of said rectifier circuit portions for detecting output signals of said rectifier circuit portions; and

a voltage compensating portion for adjusting an output voltage of said DC—

DC converter on the basis of the output signals detected by said voltage detecting unit.

8. The DC—

DC converter according to claim 7, wherein said voltage compensating portion includes a voltage compensating converter circuit portion parallel-connected to said converter circuit portions and having two pairs of switching elements connected in full bridge configuration, a transformer connected to an output side of the voltage compensating converter circuit portion, and a voltage compensating rectifier circuit portion series-connected to said rectifier circuit portions and connected to said voltage compensating converter circuit portion through the transformer.

9. The DC—

DC converter according to claim 7, wherein said voltage compensating portion includes tap changing circuits which are provided between said transformers and said rectifier circuit portions respectively for changing taps in secondary windings of said transformers respectively.

10. The DC—

DC converter according to claim 7, further comprising;

fault detecting units provided in said converter circuit portions and in said rectifier circuit portions respectively for detecting signals to said converter circuit portions and signals from said rectifier circuit portions; and

an fault judging circuit for outputting gate blocking signals for turning off said switching elements to said converter circuit portions on the basis of signals detected by said fault detecting units.

11. A bi-directional DC—

DC converter comprising;

n sets of first converter circuit portions connected in parallel to one another, each of which includes two pairs of anti-parallel diode-provided switching elements connected in full bridge configuration;

n sets of second converter circuit portions connected in parallel to one another, each of which includes two pairs of anti-parallel diode-provided switching elements connected in full-bridge configuration; and

transformers provided between said first and second converter circuit portions so that said first converter circuit portions are connected to said second converter circuit portions through the transformers respectively;

wherein in said n sets of first converter circuit portions or said n sets of second converter circuit portions located on an input side, inverter operations are performed in a timing in which a switching phase of one switching element in each pair of switching elements included in each of said n sets of converter circuit portions is shifted by a 1/3n period from a switching phase of the other switching element in said pair of switching elements and in which switching phases of corresponding switching elements in said n sets of converter circuit portions are shifted by a 1/2n period from one another, and in the other n sets of converter circuit portions located on an output side, rectifying operations are performed by the anti-parallel diodes.

12. The bi-directional DC—

DC converter according to claim 11, further comprising;

series capacitors interposed between said first converter circuit portions and said transformers and between said second converter circuit portions and said transformers respectively.

13. The bi-directional DC—

DC converter according to claim 11, further comprising;

fault detecting units provided in said first and second converter circuit portions respectively for detecting input/output signals of said first and second converter circuit portions; and

an fault judging circuit for selectively outputting gate blocking signals for turning off said switching elements respectively to said first and second converter circuit portions on the basis of the input/output signals detected by said fault detecting units.

14. A method of controlling a DC—

DC converter having n sets of converter circuit portions, each of which includes two pairs of switching elements connected in full bridge configuration and rectifier circuit portions provided on output sides of said converter circuit portions through transformers respectively, said method comprising;

converting a power source voltage of a DC power supply into AC voltages by said converter circuit portions;

transforming the AC voltages by the transformers; and

rectifying secondary outputs of the transformers by said rectifier circuit portions,

wherein a switching phase of one switching element in each pair of switching elements included in each converter circuit portion is shifted by a 1/3n period from a switching phase of the other switching element in said pair of switching elements, and switching phases of corresponding switching elements in said converter circuit portions are shifted by a 1/2n period from one another.

15. The method of controlling a DC—

DC converter according to claim 14, further comprising;

detecting output signals of said rectifier circuit portions; and

adjusting an output voltage of said DC—

DC converter on the basis of the output signals detected from said rectifier circuit portions.

16. The method of controlling a DC—

DC converter according to claim 14, wherein the output voltage of said DC—

DC converter is adjusted by changing taps in secondary windings of said transformers respectively.

17. The method of controlling a DC—

DC converter according to claim 14, further comprising;

detecting signals to said converter circuit portions and signals from said rectifier circuit portions respectively;

comparing the detected signals with predetermined values; and

outputting gate blocking signals for turning off said switching elements to said converter circuit portions if the detected signals exceed the predetermined values.

18. A method of controlling a bi-directional DC—

DC converter having n sets of first converter circuit portions connected in parallel to one another, each of which includes two pairs of anti-parallel diode-provided switching elements connected in full bridge configuration and n sets of second converter circuit portions connected in parallel to one another, each of which includes two pairs of anti-parallel diode-provided switching elements connected in full bridge configuration, said first converter circuit portions being connected to said second converter circuit portions through transformers respectively, said method comprising;

performing inverter operations in said n sets of first converter circuit portions or said n sets of second converter circuit portions located on an input side in a timing in which a switching phase of one switching element in each pair of switching elements included in each of said n sets of converter circuit portions is shifted by a 1/3n period from a switching phase of the other switching element in said pair of switching elements and in which switching phases of corresponding switching elements in said n sets of converter circuit portions are shifted by a 1/2n period from one another; and

performing rectifying operations in the other n sets of converter circuit portions located on an output side by the anti-parallel diodes.

19. The method of controlling a bi-directional DC—

DC converter according to claim 18, further comprising;

detecting input/output signals of said first and second converter circuit portions respectively;

comparing the detected input/output signals with predetermined values; and

selectively outputting gate blocking signals for turning off said switching elements respectively to said first and second converter circuit portions if the detected input/output signals exceed the predetermined values.