Switching power circuit to supply electric-vehicle battery charger with high-frequency power

• US 5,798,630 A
• Filed: 04/22/1997
• Issued: 08/25/1998
• Est. Priority Date: 01/24/1997
• Status: Expired due to Term

• Current Assignee: Hiroshi Sakamoto
• Original Assignee: Nippon Electric Industry Company Limited
• Inventors: Sakamoto, Hiroshi, Sugimori, Katsunori
• Primary Examiner(s): TSO, EDWARD H
• Application Number:
  US08/844,816
• Time in Patent Office: 490 Days
• Field of Search: 320/137, 320/140, 320/163, 320/DIG. 28, 320/DIG. 31, 320/148, 320/149, 320/156, 363/13, 363/34, 363/37, 363/95, 363/98, 363/131, 363/132
• US Class Current: 320/137
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: H02M 1/4258 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 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 7/217 using semiconductor devices only
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers
• 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
• CPC Class Codes: Y02T 90/12 Electric charging stations

Abstract

A switching power circuit for battery charger, comprising a single-phase full-wave rectifier circuit formed of diodes, a half bridge circuit formed of first and second switching elements connected in series to each other via a diode; a reactor provided between the single-phase full-wave rectifier circuit and the half bridge circuit of the switching elements and having a secondary coil, a series circuit formed of two diodes connected in parallel across the half bridge circuit, a high-frequency transformer having a primary coil connected between the source terminal of the second switching element in the half bridge circuit and the common junction of the two capacitors in the two-capacitors series circuit a secondary coil at which a high-frequency power is delivered to a load forming a battery charger, and a control circuit consisting of a variable frequency multivibrator to turn on and off the first and second switching elements alternately.

Claims

1. A switching power circuit for battery charger, comprising:

a single-phase full-wave rectifier circuit consisting of diodes (8) to (11) to convert an AC input to a DC power;

a half bridge circuit formed of a first switching element (1) and second switching element (2) connected in series to each other via diode (19);

a reactor (21) having a primary coil connected at one end thereof to the positive terminal of said rectifier circuit and at the other end to the drain terminal of said first switching element via a diode (5), and a secondary coil connected to the drain terminal of said second switching element via a diode (4) and to the negative terminal of said rectifier circuit;

a series circuit formed of two capacitors (16) and (17) connected in parallel across said half bridge circuit;

a diode (18) connected in parallel between the source terminal of said second switching element and that of said first switching element;

a high-frequency transformer (12) having a primary coil (13) connected between the source terminal of said second switching element and the common junction of said two capacitors, and a secondary coil (14) at which a high-frequency power is delivered to a load (15) forming a battery charger; and

a control circuit (3) consisting a variable frequency multivibrator or a multivibrator driven by a VF converter having two drive circuits connected to the gate and source terminals of said first switching element and the gate and source terminals of said second switching element to turn on and off the first and second switching elements alternately.

2. A switching power circuit as set forth in claim 1, wherein the duty ratio of said first switching element is controlled to suppress the inrush current developed when an AC power is supplied.

3. A switching power circuit for battery charger, comprising:

a single-phase full-wave rectifier circuit formed of diodes (46) to (49) to convert an AC input to a DC power;

a full bridge circuit composed of a half bridge circuit formed of a first switching element (32) and second switching element (31) connected in series to each other via a diode (39) and a half bridge circuit formed of a third switching element (33) and fourth switching element (34) connected in series to each other via a diode (40), connected in parallel to each other;

a first reactor (51) having a primary coil connected at one end thereof to the positive terminal of said rectifier circuit and at the other end to the drain terminal of said first switching element via a diode (43), and a secondary coil connected to the drain terminal of said second switching element via a diode (41) and to the negative terminal of said rectifier circuit;

a second reactor (52) having a primary coil connected at one end thereof to the positive terminal of said rectifier circuit and at the other end to the drain terminal of said third switching element via a diode (44), and a secondary coil connected to the drain terminal of said second switching element via a diode (42) and to the negative terminal of said rectifier circuit;

a capacitor (45) connected in parallel across said first half bridge circuit;

a series circuit formed of two diodes (35) and (36), with said diode (35) being connected in parallel between the drain and source terminals of said second switching element and said diode (36) being connected in parallel between the source terminal of said second switching element and that of said first switching element;

a series circuit formed of two diodes (37) and (38), with said diode (37) being connected in parallel between the drain and source terminals of said fourth switching element and said diode (38) being connected in parallel between the source terminal of said fourth switching element and that of said third switching element;

a high-frequency transformer (54) having a primary coil (56) connected between the source terminal of said second switching element and the source terminal of said fourth switching element, and a secondary coil (57) at which a high-frequency power is delivered to a load (55) forming a battery charger; and

a control circuit (53) consisting of a variable frequency multivibrator or a multivibrator driven by a VF converter having four drive circuits connected to the gate and source terminals of said four switching elements, respectively, in said full bridge circuit to turn on and off a group of said first and fourth switching elements and a group of said second and third switching elements alternately.

4. A switching power circuit as set forth in claim 3, wherein the duty ratios of said first and third switching elements being turned on and off alternately is controlled to suppress the inrush current developed when an AC power is supplied.