Motor vehicle electrical system

• US 4,491,779 A
• Filed: 10/12/1983
• Issued: 01/01/1985
• Est. Priority Date: 10/12/1983
• Status: Expired due to Term

• Current Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Campbell, Robert W., Ruff, Donald O.
• Primary Examiner(s): HICKEY, ROBERT
• Application Number:
  US06/541,242
• Time in Patent Office: 447 Days
• Field of Search: 320/6, 320/15, 320/16, 320/17, 320/59, 320/61, 320/57, 322/89, 322/90
• US Class Current: 320/123
• CPC Class Codes: H02J 7/1423 with multiple batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A multivoltage electrical system for a motor vehicle that has a pair of storage batteries which, in a first charging mode are charged in series from the direct voltage output terminals of a bridge rectifier connected to an alternating current generator. In a second charging mode, only one of the batteries is charged and this takes place when a plurality of controlled rectifiers connecting the generator and a common junction of the batteries are gated conductive. The switching between modes is a function of the voltage of one of the batteries and the voltage of a triangular voltage waveform generator operating at a fixed frequency. The system is maintained in the second mode when generator speed is below a predetermined value.

Claims

1. A battery charging system for a multivoltage motor vehicle electrical system comprising, first and second storage batteries, an alternating current generator having a polyphase output winding, a bridge rectifier having AC input terminals connected to said output winding and direct voltage output terminals, means connecting said batteries in series and across said direct voltage output terminals of said bridge rectifier, the negative terminal of one battery and the positive terminal of the other battery being connected to common terminal means, a plurality of controlled rectifiers having their anode-cathode circuits connected between said output winding and said common terminal means whereby only one of said batteries is charged by said generator when said controlled rectifiers are gated conductive, a ramp voltage generator, means for developing a control voltage that is a function of the voltage across the battery that is not charged when said controlled rectifiers are conductive, and means responsive to the relative magnitudes of the ramp voltage developed by said ramp voltage generator and control voltage for causing said controlled rectifiers to be gated on and off at the frequency of said ramp voltage generator.

2. A battery charging system for a motor vehicle comprising, first and second storage batteries, means connecting said batteries in series with the negative terminal of one battery and the positive terminal of the other battery connected together and to a common junction, an alternating current generator driven by the engine of said vehicle having a polyphase output winding, a polyphase full-wave bridge rectifier having AC input terminals connected to said output winding and direct voltage output terminals, means connecting said batteries across said direct voltage output terminals whereby in a first charging mode said batteries are charged in series by the direct voltage output of said bridge rectifier, a circuit including a switching means for connecting said output winding to said common junction operative to charge only one of said batteries from said generator when said switching means is conductive to thereby place said system in a second battery charging mode, a triangular waveform voltage generator developing a triangular voltage having a constant frequency, and comparator means coupled to said switching means responsive to the relative magnitudes of said triangular voltage and a direct voltage that is a function of the voltage across the battery that is not charged when said switching means is conductive for causing said system to operate alternately between said first and second charging modes at the frequency of said triangular waveform voltage generator, the time period that said system is in each mode being a function of said relative voltage magnitudes.

3. A battery charging system for a motor vehicle comprising, first and second storage batteries, means connecting said batteries in series with the negative terminal of one battery and the positive terminal of the other battery connected together and to a common junction, an alternating current generator driven by the engine of said vehicle having a polyphase output winding, a polyphase full-wave bridge rectifier having AC input terminals connected to said output winding and direct voltage output terminals, means connecting said batteries across said direct voltage output terminals whereby in a first charging mode said batteries are charged in series by the direct voltage output of said bridge rectifier, a circuit including a switching means for connecting said output winding to said common junction operative to charge only one of said batteries from said generator when said switching means is conductive to thereby place said system in a second battery charging mode, means connected to said switching means operative to cause said charging system to operate alternately between said first and second charging modes, and means for maintaining said system in said second charging mode until generator speed exceeds a predetermined value.

4. A battery charging system for a motor vehicle comprising, first and second storage batteries, means connecting said batteries in series with the negative terminal of one battery and the positive terminal of the other battery connected together and to a common junction, an alternating current generator driven by the engine of said vehicle having a polyphase output winding, a polyphase fullwave bridge rectifier having AC input terminals connected to said output winding and direct output terminals, means connecting said batteries across said direct voltage output terminals whereby in a first charging mode said batteries are charged in series by the direct voltage output of said bridge rectifier, a circuit including a plurality of controlled rectifiers connecting said output winding to said common junction operative to charge only one of said batteries from said generator when said controlled rectifiers are conductive to thereby place said system in a second battery charging mode, means connected to said controlled rectifiers operative to cause said charging system to operate alternately between said first and second charging modes, and means for maintaining said system in said second charging mode until generator speed exceeds a predetermined value.

5. A battery charging system for a motor vehicle comprising, first and second storage batteries, means connecting said batteries in series with the negative terminal of one battery and the positive terminal of the other battery connected together and to a common junction, an alternating current generator having a field winding and a polyphase output winding, a polyphase full-wave bridge rectifier having AC input terminals connected to said output winding and direct voltage output terminals, means connecting said batteries across said direct voltage output terminals whereby in a first charging mode the batteries are charged in series by the direct voltage output of said bridge rectifier, a circuit including a plurality of controlled rectifiers connecting said output winding to said common junction operative to charge only one of said batteries from said generator when said controlled rectifiers are gated conductive to thereby place said system in a second battery charging mode, means connected to said controlled rectifiers operative to cause said charging system to operate alternately between said first and second charging modes, a voltage regulator including switching means and a voltage sensing circuit, means connecting said sensing circuit across one of said batteries, said switching means being biased conductive and nonconductive in accordance with variation in the voltage sensed by said sensing circuit, a plurality of field current supply diodes connected between said output winding and a field supply terminal, means connecting said field winding and said switching means of said voltage regulator in series and to said field supply terminal, and a diode connected between one of said batteries and field supply terminal poled to supply current to said field winding from said battery.

6. A battery charging system for a motor vehicle comprising, first and second storage batteries, means connecting said batteries in series with the negative terminal of one battery and the positive terminal of the other battery connected together and to a common junction, an alternating current generator driven by the engine of said vehicle having a polyphase output winding, a polyphase full-wave bridge rectifier having AC input terminals connected to said output winding and direct voltage output terminals, means connecting said batteries across said direct voltage output terminals whereby in a first charging mode said batteries are charged in series by the direct voltage output of said bridge rectifier, a circuit including switching means for connecting said output winding to said common junction operative to charge only one of said batteries from said generator when said switching means is conductive to thereby place said system in a second battery charging mode, means connected to said switching means operative to cause said charging system to operate alternately between said first and second charging modes, means responsive to the frequency of the voltage developed at a phase terminal of said output winding for maintaining said system in said second charging mode until said frequency exceeds a predetermined value, a generator voltage warning lamp, and means responsive to the amplitude of the voltage developed at said phase terminal for extinguishing said lamp when the amplitude of said voltage reaches a predetermined value.

7. A motor vehicle electrical system for providing a first load supply voltage having a first polarity referenced to ground, a second load supply voltage of an opposite polarity referenced to ground and a third load supply voltage substantially equal to the sum of said first and second voltages comprising, first and second storage batteries, means connecting the negative terminal of one of said batteries and the positive terminal of the other battery together and to ground, an alternating current generator having a polyphase output winding, a polyphase full-wave bridge rectifier having AC input terminals connected to said output winding and direct voltage output terminals, conductor means which are not electrically connected to ground connecting said batteries across the direct voltage output terminals of said bridge rectifier whereby said batteries can be charged in series from direct voltage output terminals, a plurality of controlled rectifiers, each having an anode and a cathode, means connecting the anode-cathode circuits of said controlled rectifiers between the phase terminals of said output winding and ground with one of said anodes or cathodes of said controlled rectifiers all being connected to ground, means for periodically gating said controlled rectifiers conductive to thereby cause only one of said batteries to be charged from said output winding, first and second electrical loads one end of each being connected to ground, means for connecting respective opposite ends of said loads with respective positive and negative terminals of respective batteries, and a third electrical load connectable across said series-connected batteries.