BATTERY CHARGER WITH VOLTAGE COMPARATOR CONTROL CIRCUIT WHICH IS INSENSITIVE TO LINE VOLTAGE VARIATIONS

• US 3,736,490 A
• Filed: 04/13/1971
• Issued: 05/29/1973
• Est. Priority Date: 10/17/1970
• Status: Expired due to Term

• Current Assignee: Donald K. Richards, Paul P. Rieger, William H. Fallon
• Original Assignee: Donald K. Richards, Paul P. Rieger, William H. Fallon
• Inventors: Fallon, William H., Rieger, Paul P., Richards, Donald K.
• Primary Examiner(s): Miller, J. D.
• Assistant Examiner(s): Hickey, Robert J.
• Application Number:
  US05/133,695
• Time in Patent Office: 777 Days
• Field of Search: 323/44,45 320/39,40,2,58,59,60,61 322/28
• US Class Current: 320/143
• 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 5/12 for conversion of voltage or current amplitude only
• CPC Class Codes: Y10S 320/28 Regulating transformer, e.g. high leakage, ferro-resonant

Abstract

Control circuits are disclosed, capable for use for charging batteries, for providing a first continuous power output to a load and a second supplemental controlled output responsive to the voltage level of the load. Both single phase and three phase embodiments utilize a controlled rectifier having its gate signal controlled by a signal developed on the tap of a variable resistor connected to the load. The voltage on the load is compared to a reference voltage across a zener diode so that when the load voltage drops, the controlled rectifier conducts to provide supplemental direct current output to the load. A high leakage transformer is utilized in both the single phase and three phase embodiments, the high leakage transformer acting to maintain the reference voltage across the zener during variations of line voltage, so that the control circuit is continuously operative during such line variations.

Claims

1. An electrical circuit for providing a first continuous power output and a second controlled regulated supplemental power output comprising, in combination:

a. an electrical load capable of receiving said first continuous output and said second supplemental output;

b. a source of alternating current signals;

c. a high leakage transformer having an output circuit and an input circuit coupled to said alternating current signal source;

d. rectifying means for rectifying said alternating current signal, having an output circuit and an input circuit coupled to the output circuit of said high leakage transformer;

e. first charging circuit means coupled to the output of said rectifying means and to said load for providing said first continuous power output to said load;

f. second charging circuit means for providing said second controlled regulated supplemental power output to said load at a level responsive to the voltage across said load, said second charging circuit means including;

f-1. a controlled rectifier coupled to the output of said high leakage transformer, and having an output terminal coupled to said load and a gate terminal for variable control of the conduction of said controlled rectifier;

f-2. reference voltage means coupled to the output of said rectifying means such that a reference voltage is established independently of the voltage across the load when the voltage output of said high leakage transformer exceeds a predetermined level; and

f-3. circuit control means coupled to said reference voltage means, said load, and said gate terminal for variably controlling the conduction of said controlled rectifier by comparing the voltage across said load to said reference voltage so that the controlled rectifier is rendered conductive when the voltage across said load is below a predetermined level, the conductivity being a function of said compared voltages, and the controlled rectifier is rendered non-conductive when the voltage across said load exceeds a predetermined level; and

g. wherein the peak voltage across the output circuit of said high leakage transformer remains substantially constant for nominal variations in source voltage, such that said reference voltage means continuously provides said reference voltage during nominal low voltage variations of said alternating current source.

2. The apparatus as described in claim 1 wherein said first continuous current is a function only of said alternating current source and the voltage across said electrical load, and is independent of the operation of said second charging circuit means.

3. The apparatus as described in claim 1 wherein said electrical load is to be charged to a rated voltage, and said high leakage transformer maintains said peak voltage at a value greater than said reference voltage and restrains said peak voltage to a value just nominally above said rated voltage.