Patent ID: 8302729

Claim:
An electrical power supply unit for vehicle comprising: a main power supply, a voltage converter for converting the output voltage of the main power supply to supply electrical power to an electrical actuator for the vehicle, a subsidiary power supply, which is connected in parallel with said electrical actuator for vehicle to said voltage converter to be charged by said voltage converter and to aid the electrical power supply for said electrical actuator for the vehicle by using its stored electrical power, a voltage converter temperature detection means for detecting the temperature of said voltage converter, a subsidiary power supply temperature detection means for detecting the temperature of said subsidiary power supply, an overheat prevention means for preventing the overheat of said voltage converter and said subsidiary power supply based on said detected temperature of said voltage converter and said detected temperature of said subsidiary power supply, a heat generation balance detection means for detecting the balance between a heat generation condition of said voltage converter and a heat generation condition of said subsidiary power supply based on said detected temperature of said voltage converter and said detected temperature of said subsidiary power supply, and a current control means for controlling the output current of said voltage converter and a charge discharge current flowing through said subsidiary power supply based on said detected balance between the heat generation conditions.