Generator voltage regulator

• US 4,360,772 A
• Filed: 04/15/1981
• Issued: 11/23/1982
• Est. Priority Date: 06/18/1979
• Status: Expired due to Term

• Current Assignee: General Motors Corporation (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Voss, Richard J.
• Primary Examiner(s): Hickey, R. J.
• Application Number:
  US06/254,307
• Time in Patent Office: 587 Days
• Field of Search: 322/28, 322/99, 320/64, 320/68, 320/48
• US Class Current: 322/28
• CPC Class Codes: H02H 7/065 against excitation faults
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: H02J 7/16 Regulation of the charging current or voltage by variation of field
• CPC Class Codes: Y10S 320/13 Fault detection

Abstract

A voltage regulator for the battery charging generator of a motor vehicle battery charging system. The regulator is capable of detecting various fault conditions and under certain conditions will latch a fault indicator to a latched energized state. The regulator utilizes a Zener diode as a voltage reference and is arranged to accommodate Zener diodes of varying break down voltages by trimming a resistor of the regulator voltage sensing circuit. The regulator includes an internal voltage regulating device having a regulated output voltage applied to fault detecting comparators. The output voltage of the internal regulating device is a function of the particular break down voltage of the Zener diode.

Claims

1. A voltage regulator for a motor vehicle battery charging system that includes an alternating current generator having an output winding and a field winding, a first rectifier means connected to said output winding having direct voltage output terminals, a battery connected across said output terminals of said first rectifier means and second rectifier means connected to said output winding having field energizing terminals providing a direct field energizing voltage comprising, transistor switching means having a collector-emitter circuit adapted to be connected in series with the field winding of said generator, first and second conductor means adapted to be connected with said field energizing terminals, first and second transistors for controlling the switching of said transistor switching means, a resistor, means connecting said resistor, the collector-emitter circuit of said first transistor and the base-emitter circuit of said transistor switching means in series and across said conductor means, means connecting the collector-emitter circuit of said second transistor in shunt with the base-emitter circuit of said transistor switching means, said first transistor when conductive providing base drive for said transistor switching means through said resistor and said second transistor when conductive bypassing the base-emitter circuit of said transistor switching means, voltage comparator means, means connecting the output of said voltage comparator means with the base electrodes of said first and second transistors such that said comparator can operate said transistors to a first state in which said first transistor is conductive and said second transistor is nonconductive or a second state in which said first transistor is nonconductive and second transistor is conductive, a voltage sensing means adapted to be connected across the battery of the vehicle charging system, means connected to said voltage sensing means for providing a reference voltage, said sensing means providing a battery voltage that is a function of sensed battery voltage, means for applying said reference and battery voltages to said comparator means, said comparator means operative to cause said first and second transistors to assume said first state when said battery voltage is less than said reference voltage and to assume said second state when said battery voltage is greater than said reference voltage, third and fourth transistors, means connecting the collector-emitter circuit of said third transistor in shunt with the base-emitter circuit of said first transistor, means connecting the collector-emitter circuit of said fourth transistor in series with the base-emitter circuit of said second transistor, a Zener diode, and means connecting said Zener diode between one of said conductor means and the base electrodes of said third and fourth transistors, said Zener diode being adapted to conduct to thereby bias said third and fourth transistor conductive when the voltage at said field energizing terminals increases to an abnormally high value, the conduction of said third transistor biasing said first transistor nonconductive and the conduction of said fourth transistor biasing said second transistor conductive to thereby bias said transistor switching means nonconductive.

2. A voltage regulated motor vehicle battery charging system comprising, an alternating current generator having an output winding and a field winding, first rectifier means connected to said output winding having direct voltage output terminals, a battery connected across the output terminals of said first rectifier means to be charged thereby, second rectifier means connected to said output winding having first and second field energizing terminals providing a direct field energizing voltage, a voltage regulator having a voltage sensing circuit connected across said battery, first transistor switching means connected in series with said field winding across said field energizing terminals, a voltage responsive control circuit coupled to said voltage sensing circuit and to said transistor switching means for controlling the operation of said transistor switching means to control field current, a second transistor having its collector-emitter circuit connected between said voltage sensing circuit and said control circuit, first voltage responsive means connected to said second transistor for causing said second transistor to be biased conductive when a voltage is applied to said first voltage responsive means that exceeds a predetermined value, a circuit including a manually operable switch and a resistor connected in series between said battery and said first field energizing terminal, a signal lamp, a third transistor connected to said signal lamp operative when conductive to cause said signal lamp to be energized from said battery through said manually operable switch when it is closed, second voltage responsive means, means coupling said second voltage responsive means to said third transistor such that said third transistor is biased conductive to energize said lamp when the voltage sensed by said second voltage responsive means is below a predetermined value, and means connecting said first field terminal to said first and second voltage responsive means for applying a voltage to said first voltage responsive means which is high enough to cause said second transistor to be biased conductive but which is low enough to cause said second voltage responsive means to bias said third transistor conductive to energize said signal lamp, the conduction of said second transistor operative to energize said control circuit to thereby cause a forward bias to be applied to said first transistor switching means to cause it to conduct whereby during initial excitation of said system, when said manually operable switch is closed, said signal lamp is energized and said field winding is initially excited from said battery through said resistor, the voltage at said first field terminal rising to a value sufficient to cause said second voltage responsive means to deenergize said signal lamp when the generator develops a predetermined output voltage.