Generator voltage regulator

• US 4,345,199 A
• Filed: 03/06/1981
• Issued: 08/17/1982
• 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, ROBERT
• Application Number:
  US06/241,454
• Time in Patent Office: 529 Days
• Field of Search: 322/28, 322/73, 322/99, 320/64, 320/68, 361/20, 361/21
• 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 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• 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 rectifier means connected to the output winding and a battery connected with the rectifier means to be charged thereby comprising, a voltage sensing circuit adapted to be connected across the battery of a battery charging system for sensing battery voltage, a Zener diode, means connecting said Zener diode with said voltage sensing circuit, reference conductor means connected to one side of said Zener diode providing a substantially constant reference voltage, voltage regulating means connected between said voltage sensing circuit and first and second conductor means, means including said Zener diode for controlling said voltage regulating means so as to maintain a substantially constant regulated voltage across said first and second conductor means the magnitude of which is a function of the break down voltage of said Zener diode, a field current control means adapted to be connected in series with the field winding of said generator, means coupled to said reference conductor means and to said voltage sensing circuit for controlling said field current control means to thereby regulate the output voltage of the generator to a desired regulated value, and fault detecting comparator means for detecting a condition of operation wherein the voltage sensed by said voltage sensing circuit differs by more than a desired amount from a desired regulated value, said comparator means comprising voltage developing means connected across said first and second conductor means and coupled to said voltage sensing circuit for providing a control voltage that is a function of the regulated voltage applied to said first and second conductor means and the voltage sensed by said voltage sensing circuit, said comparator means including means connected to respond to a predetermined difference in said control voltage and said reference voltage.

2. 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 rectifier means connected to the output winding and a battery connected with the rectifier means to be charged thereby comprising, a voltage sensing circuit adapted to be connected across the battery of a battery charging system for sensing battery voltage, a Zener diode, means coupling said Zener diode with said voltage sensing circuit, reference conductor means connected to one side of said Zener diode providing a substantially constant reference voltage, a voltage control means having an output connected to first and second conductor means comprising a transistor having its collector-emitter circuit connected in series between said voltage sensing circuit and one of said first and second conductor means, means including said Zener diode for controlling the conduction of said transistor so as to maintain a substantially constant regulated voltage across said first and second conductor means the magnitude of which is a function of the break down voltage of said Zener diode, a field current control means adapted to be connected in series with the field winding of said generator, means coupled to said reference conductor means and to said voltage sensing circuit for controlling said field current control means to thereby regulate the output voltage of the generator to a desired regulated value, and fault detecting comparator means for detecting a condition of operation wherein the voltage sensed by said voltage sensing circuit differs by more than a desired amount from a desired regulated value, said comparator means comprising voltage developing means connected across said first and second conductor means and coupled to said voltage sensing circuit for producing a control voltage that is a function of the regulated voltage applied to said conductor means and the voltage sensed by said voltage sensing circuit, said comparator means including means connected to respond to a predetermined difference in said control voltage and said reference voltage.

3. 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 rectifier means connected to the output winding and a battery connected with the rectifier means to be charged thereby comprising, a voltage sensing circuit adapted to be connected across the battery of a battery charging system for sensing battery voltage, a Zener diode, means coupling said Zener diode with said voltage sensing circuit, reference conductor means connected to one side of said Zener diode providing a substantially constant reference voltage, a voltage control means having an output connected to first and second conductor means comprising a transistor having its collector-emitter circuit connected in series between said voltage sensing circuit and one of said first and second conductor means, means including said Zener diode for controlling the conduction of said transistor so as to maintain a substantially constant regulated voltage across said first and second conductor means the magnitude of which is a function of the break down voltage of said Zener diode, a field current control means adapted to be connected in series with the field winding of said generator, means coupled to said reference conductor means and to said voltage sensing circuit for controlling said field current control means to thereby regulate the output voltage of the generator to a desired regulated value, and fault detecting comparator means for detecting a condition of operation wherein the voltage sensed by said voltage sensing circuit differs by more than a desired amount from a desired regulated value, said comparator means comprising voltage divider means connected across said first and second conductor means, said voltage divider means having a junction, means for causing the voltage at said junction to vary as a function of the voltage sensed by said voltage sensing means whereby the voltage at said junction is a function of the regulated voltage applied to said first and second conductor means and the voltage sensed by said sensing circuit, said comparator means including means connected to respond to a predetermined difference in the voltage of said junction and said reference voltage.

4. 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 rectifier means connected to the output winding and a battery connected with the rectifier means to be charged thereby comprising, a voltage sensing circuit adapted to be connected across the battery of a battery charging system for sensing battery voltage, said voltage sensing circuit comprising a plurality of series-connected resistors having a first junction, at least one of said resistors having a negative temperature coefficient of resistance, the voltage of said first junction being a function of the voltage applied to said sensing circuit and the temperature of said voltage regulator, a Zener diode, means coupling said Zener diode with said voltage sensing circuit, reference conductor means connected to one side of said Zener diode providing a substantially constant reference voltage, a voltage control means having an output connected to first and second conductor means comprising a first transistor having its collector-emitter circuit connected in series between said voltage sensing circuit and one of said first and second conductor means, means including said Zener diode for controlling the conduction of said first transistor so as to maintain a substantially constant regulated voltage across said first and second conductor means the magnitude of which is a function of the break down voltage of said Zener diode, a second transistor having its collector-emitter circuit connected across said first and second conductor means, means connecting the base of said second transistor to said first junction, the emitter of said second transistor providing a voltage that varies with the voltage of said first junction, a field current control means adapted to be connected in series with the field winding of said generator, means coupled to said reference conductor means and to the emitter of said second transistor for controlling said field current control means to thereby regulate the output voltage of the generator to a desired regulated value, and fault detecting comparator means for detecting a condition of operation wherein the voltage sensed by said voltage sensing circuit differs by more than a desired amount from a desired regulated value, said comparator means comprising a voltage developing circuit connected across said first and second conductor means that includes in a series connection a plurality of resistors and the collector-emitter circuit of a third transistor, means connecting the emitter of said second transistor to the base of said third transistor, said voltage developing circuit having a second junction, said comparator means including means connected to respond to a predetermined difference in the voltage of said second junction and said reference voltage.

5. A voltage regulator for regulating the output voltage of a generator connected to supply charging current to a battery of a motor vehicle electrical system comprising, a voltage sensing circuit adapted to be connected across the battery to sense battery voltage, said voltage sensing circuit including a voltage divider comprised of first and second series-connected resistor means having a junction, one of said resistor means having a temperature dependent resistance whereby the voltage divider ratio of said voltage divider is a function of the temperature of the voltage regulator, a Zener diode, means coupling said Zener diode to said voltage sensing circuit, first conductor means connected to one side of said Zener diode providing a substantially constant reference voltage, second conductor means connected to said voltage divider junction, a field current control means adapted to be connected in series with the field winding of said generator so as to control field current, voltage responsive means connected to said first and second conductor means and to said field current control means for controlling the operation of said field current control means as a function of the relative voltages of said first and second conductor means to thereby regulate the output voltage of the generator to a desired regulated value, the relative resistance values of said first and second resistor means being related to the magnitude of the break down voltage of said Zener diode to thereby provide input voltages to said voltage responsive means to desired magnitudes to provide desired voltage regulation, a voltage regulating means having an input connected to said voltage sensing circuit and having an output, said voltage regulating means comprising means connected to said Zener diode for maintaining the voltage at its output at a substantially constant magnitude which is a function of the break down voltage of said Zener diode, and at least one fault detecting comparator means for detecting a condition of operation wherein the voltage sensed by said voltage sensing circuit differs by more than a desired amount from a desired regulated value, said comparator means including means coupled to the output of said voltage regulating means and said second conductor means for producing a control voltage which is a function of the output voltage of said voltage regulating means and the voltage of said second conductor means, said comparator means including means connected to respond to a predetermined difference in said control voltage and the voltage of said first conductor means.