DC power source device and power conversion method using a single drive power supply

Patent metadata

Field	Value
Publication number	US-9231487-B2
Application number	US-201214116686-A
Country	US
Kind code	B2
Filing date	May 1, 2012
Priority date	May 10, 2011
Publication date	Jan 5, 2016
Grant date	Jan 5, 2016

Abstract

FETs disposed in a DC/DC converter are each driven by a drive transformer. A voltage from a single drive power supply disposed in common for the FETs is divided into positive and negative biases to be applied to the FETs, and an operational state of the FETs is detected based on voltage signals. A sequence circuit turns on an input from a three-phase AC power supply by driving a relay circuit at a time point when it is confirmed that the FETs have normally started stable ON/OFF operation, and drives a power factor improvement circuit, which converts AC voltage from the three-phase AC power supply into a DC voltage by simultaneously performing full-wave rectification and power factor improvement.

First claim

The invention claimed is:

1. A DC power supply device, comprising:
a power factor improvement circuit for converting an AC voltage from an AC power supply into a DC voltage by performing full-wave rectification while improving a power factor;
a DC/DC converter for converting the DC voltage from the power factor improvement circuit into a low DC voltage to be supplied to a load;
a relay circuit disposed between the AC power supply and the power factor improvement circuit so as to switch between on and off of an input from the AC power supply; and
a sequence circuit connected to the power factor improvement circuit, the DC/DC converter, and the relay circuit, wherein:
the DC/DC converter comprises:
a plurality of FETs connected to each other to form a full bridge;
a plurality of FET driving circuits respectively connected to the plurality of FETs, for driving the plurality of FETs;
a single drive power supply connected in common to all the plurality of FET driving circuits; and
a phase control circuit for outputting, to the plurality of FET driving circuits, a control signal for controlling on and off phases of the plurality of FETs;

each of the plurality of FET driving circuits in a normal operation divides an output voltage from the single drive power supply into a positive and negative biases to apply the positive and negative biases to corresponding one of the plurality of FETs in accordance with the control signal from the phase control circuit;
the sequence circuit detects an operational state of the DC/DC converter and outputs a drive signal for operating the relay circuit and the power factor improvement circuit at a time point when it is confirmed that the plurality of FETs of the DC/DC converter have started the normal operation under control by the phase control circuit; and
the relay circuit and the power factor improvement circuit are turned on in accordance with the drive signal from the sequence circuit.

2. The DC power supply device according to claim 1 , wherein:
the each of the plurality of FET driving circuits comprises a drive transformer; and
the drive transformer changes a voltage on a primary side to both positive and negative sides in accordance with ON/OFF of the control signal from the phase control circuit, and thus generates positive and negative voltages on a secondary side in proportion to an ON/OFF ratio of the drive signal so as to apply the positive and negative voltages to a gate of corresponding one of the plurality of FETs.

3. A power conversion method, comprising the steps of:
outputting a control signal for controlling on and off phases of a plurality of FETs connected to each other to form a full bridge;
dividing an output voltage from a single drive power supply into positive and negative biases and applying the positive and negative biases to the plurality of FETs in accordance with the control signal in a normal operation;
detecting a drive state of the plurality of FETs;
outputting a drive signal at a time point when it is confirmed that the plurality of FETs have started the normal operation under control by the control signal based on a result of the detecting;
converting an AC voltage from an AC power supply into a DC voltage by performing full-wave rectification while improving a power factor in accordance with the drive signal; and
converting the DC voltage obtained after the full-wave rectification into a low DC voltage to be supplied to a load.

Assignees

• Suzuki Yasuji
• Mitsubishi Electric Corp

Inventors

• Suzuki Yasuji

Classifications

• H02M1/4258

  using a single converter stage both for correction of AC input power factor and generation of a regulated and galvanically isolated DC output voltage (H02M1/4241 takes precedence) · CPC title

• H02M1/4241

  using a resonant converter · CPC title

• H02M1/4208

  Arrangements for improving power factor of AC input · CPC title

• H02M7/219

  in a bridge configuration · CPC title

• H02M3/33592

  having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer · CPC title