Dual-voltage battery charging system

• US 4,516,066 A
• Filed: 07/29/1983
• Issued: 05/07/1985
• Est. Priority Date: 07/29/1983
• 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: Nowakowski, Robert J.
• Primary Examiner(s): HICKEY, ROBERT
• Application Number:
  US06/518,669
• Time in Patent Office: 648 Days
• Field of Search: 320/6, 320/14, 320/15, 320/17, 320/61, 320/64, 320/68, 320/67, 320/19, 322/69, 322/70, 322/89, 322/90, 322/28, 307/16
• 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 battery charging system for a dual-voltage motor vehicle electrical system that has a pair of series-connected batteries that can energize an electric cranking motor. One of the batteries is charged from a diode-rectified alternating current generator. A voltage regulator regulates the output voltage of the generator and includes a switching means connected in series with the field winding of the generator to control field current. The other battery is charged by field discharge current that is produced by the voltage induced in the generator field winding when the switching means is switched to a nonconductive state.

Claims

1. A battery charging system for a dual-voltage motor vehicle electrical system comprising, first and second series-connected batteries, a generator having an output winding connected in circuit with said first battery for charging said first battery and having a field winding, means for energizing said field winding comprising a switching means connected in series with said field winding, means for causing said switching means to switch between conductive and nonconductive states as a function of the magnitude of the voltage generated in said output winding, and circuit means connecting said field winding to the terminals of said second battery for charging said second battery by field discharge current produced by the voltage induced in said field winding when said switching means is switched to a nonconductive state.

2. A battery charging system for a dual-voltage motor vehicle electrical system comprising, first and second series-connected batteries, an alternating current generator having an output winding and a field winding, rectifier means connected with said output winding and with said first battery for supplying charging current to said first battery, a field circuit for energizing said field winding from said output winding, voltage regulator means for maintaining the voltage applied to said first battery at a desired regulated value, said voltage regulator means comprising a switching means connected in series with said field winding and means responsive to the voltage applied to said first battery for controlling the switching state of said switching means, and circuit means including a diode connecting said field winding to the terminals of said second battery for charging said second battery by field discharge current produced by the voltage induced in said field winding when said switching means is switched to a nonconductive state.

3. A motor vehicle electrical system comprising, an accessory battery connectable to motor vehicle accessory loads, a cranking battery having a lower terminal voltage than said accessory battery, means connecting said batteries in series, an electric cranking motor, circuit means for energizing said cranking motor by said series-connected batteries, a generator having a field winding, said generator having an output winding connected to said accessory battery for supplying charging current thereto, voltage regulator means for maintaining the voltage applied to said accessory battery at a desired regulated value, said voltage regulator means comprising a switching means connected in series with said field winding and means responsive to the magnitude of the voltage applied to said accessory battery for controlling the switching state of said switching means, and circuit means connecting said field winding to the terminals of said cranking battery for charging said cranking battery by field discharge current produced by the voltage induced in said field winding when said switching means is switched to a nonconductive state.

4. A battery charging system for a dual-voltage motor vehicle electrical system comprising, first and second series-connected batteries, a generator having an output winding connected in circuit with said first battery for charging said first battery and having a field winding, means for energizing said field winding comprising a switching means connected in series with said field winding, means for causing said switching means to switch between conductive and nonconductive states as a function of the magnitude of the voltage generated in said output winding, circuit means connecting said field winding to the terminals of said second battery for charging said second battery by field discharge current produced by the voltage induced in said field winding when said switching means is switched to a nonconductive state, means for sensing the terminal voltage of said second battery and means coupled to said sensing means for terminating charging of said second battery when the terminal voltage of said second battery attains a predetermined value.

5. A battery charging system for a dual-voltage motor vehicle electrical system comprising, first and second series-connected batteries, an alternating current generator having an output winding and a field winding, rectifier means connected with said output winding and with said first battery for supplying charging current to said first battery, a field circuit for energizing said field winding from said output winding, voltage regulator means for maintaining the voltage applied to said first battery at a desired regulated value, said voltage regulator means comprising a switching means connected in series with said field winding and means responsive to the voltage applied to said first battery for controlling the switching state of said switching means, circuit means including a diode connecting said field winding to the terminals of said second battery for charging said second battery by field discharge current produced by the voltage induced in said field winding when said switching means is switched to a nonconductive state and means responsive to the terminal voltage of said second battery for diverting field discharge current into a current path that does not include said second battery when the terminal voltage of said second battery attains a predetermined value.

6. A battery charging system for a dual-voltage motor vehicle electrical system comprising, first and second series-connected batteries, an alternating current generator having an output winding and a field winding, rectifier means connected with said output winding and with said first battery for supplying charging current to said first battery, a field circuit for energizing said field winding from said output winding, voltage regulator means for maintaining the voltage applied to said first battery at a desired regulated value, said voltage regulator means comprising a switching means connected in series with said field winding and means responsive to the voltage applied to said first battery for controlling the switching state of said switching means, circuit means including a diode connecting opposite ends of said field winding to the terminals of said second battery for charging said second battery by field discharge current produced by the voltage induced in said field winding when said switching means is switched to a nonconductive state, the anode of said diode being connected to one end of said field winding, a controlled rectifier having an anode connected to the end of said field winding that is connected to the anode of said diode, a circuit connecting the opposite end of said field winding to the cathode of said controlled rectifier that provides part of a circuit for field discharge current that does not include said second battery when said controlled rectifier is gated conductive and means for gating said controlled rectifier conductive when the terminal voltage of said second battery attains a predetermined value.