Power supply apparatus for a vehicle having batteries of different voltages which are charged according to alternator speed

• US 5,418,401 A
• Filed: 10/23/1992
• Issued: 05/23/1995
• Est. Priority Date: 10/29/1991
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Kaneyuki, Kazutoshi
• Primary Examiner(s): Pellinen, A. D.
• Assistant Examiner(s): Fleming, Fritz M.
• Application Number:
  US07/965,026
• Time in Patent Office: 942 Days
• Field of Search: 307/9.1, 307/10.1, 307/10.7, 307/39, 307/86, 307/120, 307/16, 307/29, 320/15, 320/41, 322/8, 322/29, 322/90
• US Class Current: 307/10.1
• 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 power supply apparatus for a vehicle includes an alternator for generating an output voltage for charging a first battery and a second battery having a higher voltage than the first battery. The output voltage of the alternator is controlled by a voltage regulator in accordance with the rotational speed of the alternator. When the rotational speed is in a low speed range, the voltage regulator controls the output voltage of the alternator to a first value suitable for charging the first battery. When the rotational speed is in a high speed range, the voltage regulator controls the output voltage of the alternator to a second value higher than the first value and suitable for charging the second battery. The output voltage of the alternator is switched between the first value and the second value at a rotational speed at which the output power of the alternator at the first output voltage equals the output power at the second output voltage. The apparatus may include a voltage converter which reduces the output voltage of the alternator to a voltage suitable for charging the first battery when the alternator is generating power at the second voltage. Alternatively, when the alternator is generating power at the second voltage, a point of the armature winding of the alternator having a voltage less than the output voltage of the alternator may be connected to the first battery to charge the first battery.

Claims

1. A power supply apparatus comprising:

an alternator (1) having an armature winding (2) and a field winding (3);

first and second output terminals (6,

     7) connected to the armature winding;

a first discrete, relatively low voltage battery (10);

a switch (15) connected between the first output terminal and the first battery and having first and second positions;

a second discrete battery (12), separate and distinct from said first battery, connected to the second output terminal and having a higher voltage than the first battery; and

switch control means (20) for switching the switch between the first and second positions according to the rotational speed of the alternator;

voltage regulating means for controlling the alternator to maintain the voltage at the output terminals at a first voltage higher than the voltage of the first battery and lower than the voltage of the second battery when the switch is in its first position and maintain the voltage at the output terminals at a second voltage higher than the voltage of the second battery when the switch is in its second position; and

a third output terminal connected to the armature winding at a point having a voltage lower than the voltage at the first or second output terminals, wherein the switch is connected to the first output terminal and the third output terminal, and the first output terminal is connected by the switch to the first battery when the switch is in its first position and the third output terminal is connected by the switch to the first battery when the switch is in its second position.

2. A power supply apparatus as claimed in claim 1 wherein the alternator is a three-phase alternator having first through third armature windings, each armature winding having a first end and a second end, the three armature windings being connected together at their first ends to form a Y-connection, the third output terminal being connected to the first ends of the armature windings.

3. A power supply apparatus as claimed in claim 1 wherein the alternator is a three-phase alternator having first through third armature windings, each armature winding having a first end and a second end, the three armature windings being connected together at their first ends to form a Y-connection, the third output terminal being connected to the second end of one of the armature windings.