| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem in which the output voltage of an inverter INV decreases in precision because of restrictions for reducing electromagnetic noise generated due to an ON/OFF operation of a switching element S¥# constituting the inverter INV.SOLUTION: A PWM processing section 40 generates an operation signal g¥# for making the output voltage of an inverter INV into command voltages vu*, vv*, and vw* and outputs the operation signal g¥# to the inverter INV. Here, the generation processing of the operation signal g¥# is PWM processing. This is carried out using a carrier signal Sc of an asynchronous carrier generation section 42 or a synchronous carrier generation section 46. When a value obtained by adding an electric angular frequency to the double of a carrier frequency is a prescribed frequency in asynchronous PWM processing based upon the carrier signal Sc of the asynchronous carrier generation section 42, the processing is switched to synchronous PWM processing based upon the carrier signal SC of the synchronous carrier generation section 46 to lower the carrier frequency. |
