Dual type vehicle power-supply apparatus

Abstract

The dual type vehicle power-supply apparatus includes a bidirectional power transmission unit capable of performing bidirectional electric power transmission between a high voltage source of a high power-supply voltage supply system and a low voltage source of a low power-supply voltage supply system, and a power transmission controller controlling the bidirectional power transmission unit to perform the bidirectional electric power transmission. The power transmission controller has a function of detecting a surplus amount of electric power in the low power-supply voltage supply system, a function of detecting a shortage amount of electric power in the high power-supply voltage supply system, and a function of commanding the bidirectional power transmission unit to transmit electric power from the low voltage source to the high voltage source by an mount equal to the detected shortage amount when the detected surplus amount is larger than the detected shortage amount.

1 . A dual type vehicle power-supply apparatus comprising: 
 a high power-supply voltage supply system having a high voltage source supplying a high power-supply voltage to a high voltage electrical load;    a low power-supply voltage supply system having a low voltage source supplying a low power-supply voltage lower than said high power-supply voltage to a low voltage electrical load;    a bidirectional power transmission unit capable of performing bidirectional electric power transmission between said high voltage source and said low voltage source; and    a power transmission controller controlling said bidirectional power transmission unit to perform said bidirectional electric power transmission,    wherein,    said power transmission controller includes:    a first function of detecting a surplus amount of electric power in said low power-supply voltage supply system;    a second function of detecting a shortage amount of electric power in said high power-supply voltage supply system; and    a third function of commanding said bidirectional power transmission unit to transmit electric power from said low voltage source to said high voltage source by an amount equal to said detected shortage amount when said detected surplus amount is larger than said detected shortage amount.    
   
   
       2 . The dual type vehicle power-supply apparatus according to  claim 1 , wherein said first function is configured to detect said surplus amount on the basis of an electric power supply capacity of said low voltage source of said low power-supply voltage supply system, and an electric power amount which said low voltage electrical load requires for a certain time period after electric power transmission from said high voltage source to said low voltage source by said bidirectional power transmission unit is stopped.  
   
   
       3 . The dual type vehicle power-supply apparatus according to  claim 1 , wherein said second function is configured to detect said shortage amount on the basis of an electric power supply capacity of said high voltage source of said high power-supply voltage supply system, and an amount of an impending electric power demand by said high voltage electrical load.  
   
   
       4 . The dual type vehicle power-supply apparatus according to  claim 3 , wherein said high voltage source includes a main battery charged by a generator driven by a vehicle engine, and said low voltage source includes an auxiliary battery charged by said bidirectional power transmission unit.  
   
   
       5 . The dual type vehicle power-supply apparatus according to  claim 4 , wherein said power transmission controller includes a fourth function of detecting a degree of degradation of said auxiliary battery, and a fifth function of increasing a charging level of said main battery if said degree of degradation of said auxiliary battery detected by said fourth function is lower than a predetermined degree, and increasing a charging level of said auxiliary battery if said degree of degradation of said auxiliary battery detected by said fourth function is not lower than said predetermined degree, to thereby make said first function larger than said shortage amount detected by said second function.  
   
   
       6 . The dual type vehicle power-supply apparatus according to  claim 4 , wherein said second function is configured to determine an electric power amount needed for starting said vehicle engine as said amount of said impending electric power demand by said high voltage electrical load.