| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce switching noise to cut back the size and the weight of a system interconnection inverter device. <P>SOLUTION: A controller 7 comprises a modulation wave generation unit 7d which generates a modulation wave having such an amplitude that the modulation degree of a pulse width modulation signal will be an optimum degree of modulation to minimize switching noise, and a PWM signal generation unit 7e which generates a pulse width modulation signal by using the modulation wave. The modulation wave generation unit 7d reads from a modulation wave table 7a waveform data on a modulation wave whose amplitude gives an optimum degree of modulation, and corrects the phase of the waveform data by using a phase (the one needed for reactive power to track a control target) calculated by a power factor adjustment unit 7b to generate a modulation wave. And the PWM signal generation unit 7e compares the level of the modulation wave with the level of a prescribed triangular wave to generate a PWM signal. Since the modulation degree of the PWM signal is fixed to an optimum degree of modulation, switching noise is suppressed. <P>COPYRIGHT: (C)2013,JPO&INPIT |
