Patent ID: 8159179

Claim:
A battery charging device that is connected between a three-phase alternating current generator having U, V, and W phases and a battery, and is constructed so as to convert alternating current power output from the three-phase alternating current generator into direct current power and supply the direct current power to the battery, and that performs advance angle/delay angle control by either advancing or delaying an energization timing to switching elements of a rectifier portion having a bridge configuration relative to a phase of the alternating current output voltage from the three-phase alternating current generator, the device comprising: an alternating current output voltage detection circuit that: detects an alternating current output voltage of any one phase of the three-phase alternating current generator, and includes a sub-coil which detects the alternating current output voltage of the any one phase of the three-phase alternating current generator; a U, V, W phase voltage generating circuit that: generates a synchronous signal that is in synchronization with an alternating current output voltage of the one phase that is detected by the alternating current output voltage detection circuit, generates synchronous signals of the other two phases based on the synchronous signal of the one phase, generates a rectangular wave that is in synchronization with the alternating current output voltage of the one phase detected by the sub-coil as the synchronous signal, generates rectangular waves that are in synchronization with the other two phases based on the rectangular wave that is in synchronization with the one phase, and outputs the rectangular waves to a synchronous triangular wave generating circuit that generates triangular waves that are in synchronization with the rectangular waves of the respective phases; an advance angle/delay angle calculation circuit that determines an advance angle/delay angle amount of the energization timing to the switching elements based on a signal of a differential voltage between a voltage of the battery and a predetermined target voltage, and the synchronous signals of the each phase that are output by the U, V, W phase voltage generating circuit; and an advance angle/delay angle control circuit that performs the advance angle/delay angle control of the switching elements using the advance angle/delay angle amount determined by the advance angle/delay angle calculation circuit.