| 摘要 |
PROBLEM TO BE SOLVED: To provide a control unit of electric vehicle, adapted to eliminate sound change in magnetic noise, as well as to control over the full range of output voltages, in a two-level inverter for use in electric vehicles. SOLUTION: A control unit of electric vehicle includes a DC power supply, and an electric power converter of two levels for converting from DC voltages to three-phase AC phase voltages with variable voltage and variable frequency by a plurality of control modes, and delivering pulses of positive and negative binary values as its phase voltage. In the control modes, an overmodulation control mode is made to intervene between a pulse width modulating control mode and 1 pulse control mode, and the overmodulation control mode is adapted to elongate gradually the period of voltage pulse from the peak of fundamental wave of the output voltage headed toward zero cross with increasing output voltage, and to continually change switching frequencies by switching control in a synchronization with the period of fundamental waves of the output voltage, thus causing switching frequencies to be gradually lowered in accordance with the increase in the output frequencies. COPYRIGHT: (C)2006,JPO&NCIPI |
