Abstract: An apparatus for battery equalization of a battery pack for use in a vehicle includes cell stack separators and cell balancers. The battery pack includes a power supply system, a plurality of cells and a plurality of cell stacks. Each cell stack includes a plurality of the cells connected in series. The cell stacks are connected in parallel to form the battery pack. Each cell stack separator is adapted to separate the corresponding cell stack from the power supply system if the difference between the maximum and the minimum of calculated internal resistances of the cells in the cell stack is greater than a predetermined threshold value. Each cell balancers is adapted to perform a battery equalization control for the cells in the separated cell stack.

Abstract: A charge and discharge control apparatus equalizes the voltages of rechargeable battery cells by using a charger or a capacitor charged by an external power source, by using a first cell balancing unit which charges the rechargeable battery cells until their voltage values become equal to the maximum voltage value of the rechargeable battery cells, and an inductor for charging or discharging adjacent rechargeable battery cells from among the rechargeable battery cells, and by using a second cell balancing unit which sequentially equalizes the voltages of the adjacent rechargeable battery cells.

Abstract: A switching circuit 13 switches transistors M1, M2 at a first high frequency f1 (100 kHz). Thereby, a DC low voltage input is converted into an AC voltage having a high frequency of 100 kHz. A transformer TR1 insulation-transfers the AC voltage of 100 kHz outputted from the switching circuit 13. Transistors M7, M8 provided in the secondary side are formed such that the state where the transistor M7 is conductive whereas the transistor M8 is non-conductive and the state where the transistor M7 is non-conductive whereas the transistor M8 is conductive are alternately changed at a second frequency f2 (55 Hz). An AC output filter 15 outputs an AC voltage corresponding to a commercial AC power source of 55 Hz, 100V to supply to a load 14. In conversion from a DC voltage to an AC voltage by use of a transformer, simplified converting operation is employed so that the circuit can be scaled down and use of a small-sized transformer is realized.

Abstract: In a multi-output power conversion circuit which drives a polyphase AC motor and another device but the polyphase AC motor using a DC power source, a transformer is connected to the neutral point of the polyphase AC motor, an AC voltage at a zero-phase voltage frequency is obtained from the transformer, and the other device is loaded with the AC voltage.