| 摘要 |
<P>PROBLEM TO BE SOLVED: To make controllable the output voltage of a three-level inverter from zero to maximum, control three-level pulse generation that can conduct an inverter output voltage continuously and smoothly and prevent a discontinuous sound. <P>SOLUTION: In an electric power converting device in an electric vehicle provided with an electric power convertor converting a direct current to an alternating phase voltage having three-level potential that is a positive, negative and intermediate voltage, and a controller controlling the speed of acceleration and slowdown of an alternating electric motor connected with the output side of the above convertor, a low speed range in controlling the speed is provided with a first pulse width modulating and controlling range for outputting a positive and negative voltage pulse alternately through the intermediate voltage across the whole range of a half cycle of an output voltage fundamental wave in the convertor and a high speed range in controlling the speed is provided with a second pulse width modulating and controlling range having a first cycle for outputting several voltage pulses of identical polarities continuously within the half cycle of the output voltage fundamental wave of the convertor and a second cycle outputting the positive and negative voltage pulses alternately before and after the first cycle through the intemediate voltage. <P>COPYRIGHT: (C)2004,JPO |
