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A Phase-shift DC/DC Converter with a Common-mode (CM) Voltage Reduction Modulation

IP.com Disclosure Number: IPCOM000252243D
Publication Date: 2017-Dec-30
Document File: 12 page(s) / 1M

Publishing Venue

The IP.com Prior Art Database

Related People

Kai Tian: AUTHOR [+3]

Abstract

This invention disclosure is going to present a phase-shift DC/DC converter with a commonmode (CM) voltage reduction modulation. The proposed technology has the following merits: 1. The CM voltage is reduced close to zero. 2. The reduction in CM voltage can significantly reduce CM current, resulting in smaller CM filter and cost saving, as well as efficiency and power density improvement. 3. The reduction in CM voltage can also help in high-frequency (HF) transformer design in terms of parasitic capacitance and inductance optimization.

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ZCRD Corporate Research

< Doc ID >

Issued by department Last edit date Lang. Revision Page

ZCRD/CN/CRC/P&C 2017-4-24 en <Rev 01> 1/12 Doc. title Invention Disclosure Status of document draft Inventor Kevin-Kai Tian, River-Tinho Li, Ken-

YuenFaat and Merlin-Lin Ma

1 DISCLOSURE TITLE: A phase-shift DC/DC converter with a common-mode (CM) voltage reduction modulation.

2 INVENTOR: KEVIN-KAI TIAN, RIVER-TINHO LI, KEN-KUENFAAT YUEN AND MERLIN- LIN MA

3 ABSTRACT OF THE INVENTION 3.1 Background of the invention

This invention disclosure is going to present a phase-shift DC/DC converter with a common- mode (CM) voltage reduction modulation. The proposed technology has the following merits:

1. The CM voltage is reduced close to zero. 2. The reduction in CM voltage can significantly reduce CM current, resulting in smaller CM

filter and cost saving, as well as efficiency and power density improvement. 3. The reduction in CM voltage can also help in high-frequency (HF) transformer design in

terms of parasitic capacitance and inductance optimization.

3.2 Statement of the problem

The phase-shift DC/DC converter is shown in Fig.1. There are two legs, leg A and B in this converter. For each leg, there are 4 power switches, S1~S4 for leg A, and S5~S8 for leg B. Diode 1~4 and capacitor Ca and Cb are auxiliary circuit for voltage balancing.

The existing modulation method of this converter is shown in Fig. 2, including gating signals and key waveforms. In the existing modulation, the switch S1 and S2 are seen as one switch and share the same gating signal. S3 and S4, S5 and S6, S7 and S8 are the other three groups that is seen as one switch and share same gating signals respectively. The operation principle of this converter is the same with traditional full-bridge phase-shift DC/DC converter [1, 2]. The drawback of the existing modulation is it does not consider any optimization of the converter's

A B

O

- Vdc/2

+ Vdc/2 S1

S2

S3

S4

S5

S6

S7

S8

D1

D2

D3

D4

Ca Cb

Fig. 1. A phase-shift DC/DC converter

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Doc. title Revision Page

Invention Disclosure <Rev 01> 2/12

We reserve all rights in this document and in the information contained therein. Reproduction, use or disclosure to third parties without express authority is strictly forbidden.  2010 ABB Ltd.

S1 S2 S3 S4

S5 S6 S7 S8

vAB

vAO

vBO

vcm

iL

t0 t1 t3t2 t4

Fig. 2. Gating signals and key waveforms of the converter with the existing modulation

(a) State I (vAB = +Vdc, vcm = 0) (b) State II (vAB = -Vdc, vcm = 0)

(c) State III (vAB = 0, vcm = -Vdc/2) (d) State IV (vAB = 0, vcm = +Vdc/2)

Fig. 3. Four basic states of the converter with the existing modulation

A B

O

- Vdc/2

+ Vdc/2 S1

S2

S3

S4

S5

S6

S7

S8

D1

D2

D3

D4

A B

O

- Vdc/2

+ Vdc/2 S1

S2

S3

S4

S5

S6

S7

S8

D1

D2

D3

D4

A B

O

- Vdc/2

+ Vdc/2 S1

S2

S3

S4

S5

S6

S7

S8

D1

D2

D3

D4

A B

O

- Vdc/2

+ Vdc/2 S1

S2

S3

S4

S5

S6

S7

S8

D1

D2

D3

D4

ZCRD Corporate Research

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Doc. title Revision Page

Invention Disclosure <Rev 01> 3/12

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