| 摘要 |
<P>PROBLEM TO BE SOLVED: To overcome the problem with a PWM control power conversion apparatus, wherein a large voltage distortion exceeding a tolerance occurs in a nonlinear load, such as a rectifier, although the apparatus reduces a switching loss by lowering a carrier frequency near a peak with respect to a normal carrier frequency near the zero-cross of a fundamental wave. <P>SOLUTION: The power conversion apparatus performs conversion between AC and DC by PWM control and supplies power to a load. The power conversion apparatus includes a first PWM pulse generation unit for reducing a switching frequency at least at a partial section during one period of an AC phase voltage to perform PWM control, a second PWM pulse generation unit for performing PWM control where the switching frequency during one period of the AC phase voltage is more than that at the first PWM pulse generation unit, and a voltage distortion detection means of detecting a voltage distortion of AC. When the voltage distortion exceeds a preset value, PWM control by the first PWM pulse generation unit changes to PWM control by the second PWM pulse generation unit. <P>COPYRIGHT: (C)2011,JPO&INPIT |
