Shunt control

• US 5,329,220 A
• Filed: 09/17/1990
• Issued: 07/12/1994
• Est. Priority Date: 10/27/1987
• Status: Expired due to Term

• Current Assignee: Alfred M. Hase
• Original Assignee: Alfred M. Hase
• Inventors: Hase, Alfred M.
• Primary Examiner(s): Stephan, Steven L.
• Assistant Examiner(s): KINCAID, KRISTINE LYNN
• Application Number:
  US07/583,095
• Time in Patent Office: 1,394 Days
• Field of Search: 320/21-23, 320/30-32, 320/39, 320/40, 320/43, 320/57, 320/59, 363/60, 363/86, 363/89
• US Class Current: 320/165
• 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: Y10S 320/13 Fault detection

Abstract

An electronic shunt control circuit for use in conjunction with battery charging circuits is disclosed. The circuit precludes the possibility of current eminating from charged batteries from DC biasing the control coil and shunt therefor, when there is no AC electrical energy being supplied to the circuit--such as during the occurrence of an AC power failure. Precluding such DC biasing is accomplished through the use of a plurality of blocking diodes located between the output to the battery and the control coil and shunt. A few milliamperes of current are acceptably permitted to flow back from the battery to the sensing and control circuit portion of the charging circuit, so as to maintain surveillance on the status of the battery and of the circuits; but no DC current is permitted, in the instance of an AC power outage to flow back from the battery through the control coil of the input AC reactor, due to the presence of the blocking or isolating diodes.

Claims

1. A solid state battery charging circuit having a shunt regulating control circuit, comprising:

AC power input means;

an isolating transformer, having a primary input side and a secondary output side, with said input side connected to said AC power input means, and said output side having a first terminal, a second terminal, and a third terminal, wherein said third terminal is a centre tap terminal between said first and second terminals;

a controllable synchronous switch means having a control coil, and arranged for regulating the amount of power that is input to a battery being charged by said battery charging circuit, said switch means being located on either the primary side or the secondary side of said isolating transformer;

said control coil being connected in a conductive string across the secondary side of said isolating transformer;

a pair of DC output terminals, a first one of which is connected through full wave rectifying means to said first and second terminals of said transformer output, and the other of which is connected to said centre tap terminal;

said full wave rectifying means comprising a first pair of main diodes, wherein said main diodes also preclude back current flow from a battery connected to said pair of DC output terminals;

shunt means connected in parallel to said control coil for controlling the amount of DC current flowing to said control coil;

control circuit means connected across said pair of DC output terminals to determine the output status of said full wave rectifying means, and changes thereof, and to generate control signals therefor;

said control circuit means being powered from a battery connected to said pair of DC output terminals;

auxiliary full wave rectifying means including a pair of auxiliary diodes, comprising a first auxiliary diode and a second auxiliary diode, with said first auxiliary diode having its positive terminal connected in constantly conductive relation to said first output terminal of said isolating transformer, and its negative terminal connected in conductive relation to said control coil; and

said second auxiliary diode having its positive terminal connected in constantly conductive relation to said second output terminal of said isolating transformer, and its negative terminal connected in conductive relation to the negative terminal of said first auxiliary diode;

whereby an auxiliary full wave DC voltage is produced to provide DC power for said control coil, and said shunt means, irrespective of the state of the charge of the battery being charged; and

whereby reverse current flow from said battery through said control coil, when said AC power input means is not delivering power to said battery charging circuit, is precluded.

2. The solid state battery charging circuit of claim 1, wherein said shunt means comprises an NPN transistor.

3. The solid state battery charging circuit of claim 1, wherein said shunt means comprises an PNP transistor.

4. The solid state battery charging circuit of claim 1, wherein said shunt means comprises a field effect transistor.

5. The solid state battery charging circuit of claim 1, wherein said shunt means comprises a silicon controlled rectifier.

6. The solid state battery charging circuit of claim 2, wherein said NPN transistor acts as a Class B amplifier in switch mode.

7. The solid state battery charging circuit of claim 1, wherein said synchronous switch is a saturable reactor, and the control coil therefor has no DC bias when the AC power is off.

8. The solid state battery charging circuit of claim 1, wherein said circuit is a single phase centre-tapped circuit.

9. The solid state battery charging circuit of claim 1, wherein said circuit is a single phase bridge circuit.

10. The solid state battery charging circuit of claim 1, wherein said circuit is a three phase bridge circuit.

11. The solid state battery charging circuit of claim 1, wherein said circuit is a six phase star circuit.

12. The solid state battery charging circuit of claim 1, wherein said controllable synchronous switch means has gate coils arranged in parallel.

13. The solid state battery charging circuit of claim 1, wherein said controllable synchronous switch means has gate coils arranged in series.