| 摘要 |
PROBLEM TO BE SOLVED: To use the rated capacity of a unit inverter to the utmost by reducing switching surge voltage. SOLUTION: This voltage-type inverter device is a PWM control system of voltage-type inverter where three-phase unit inverters are multiplexed, and this inputs carrier waves to be added together with voltage standard to the PWM circuits 15a and 15b corresponding to each unit inverter 11a and 11b into a carrier wave adding circuit 16, and this gets the first carrier wave which changes between 0 level of the minimum value of waveform and +1, when the positive peak value of the carrier wave is made +1 and the negative peak value is made -1, and the second carrier wave which changes between -1 level of the minimum value of waveform and 0 in the same direction with the same timing as the first carrier wave, by the carrier wave adding circuit 16, compares them with the reference voltage of each phase, makes such switching timing that the switching directions do not get in the reverse direction at the same time, and controls the switching of each unit inverter. |
