| 摘要 |
PROBLEM TO BE SOLVED: To change carrier frequency freely and smoothly in a relative proportion of a carrier waveform peak value to a voltage command peak value kept constant in as a simple circuit as possible, without being restricted by resolution of a carrier waveform. SOLUTION: According to an interrupt signal into a program, the program computes and sets a voltage command value, carrier cycle data to be set next, and a voltage command peak value correction factor. A carrier setting circuit 11 outputs a carrier cycle signal set by inputting carrier cycle data according to the first control signal. A voltage command computing circuit 21 outputs the voltage command value obtained by inputting voltage command data and multiplying it by the voltage command peak value correction factor according to the second control signal. A first carrier counter 12 outputs a carrier having a cycle set by the carrier setting circuit 11, and the interrupt signal is outputted into the program by the crests or troughs of this carrier. The first carrier counter 12 loads the carrier into the second carrier counter 17 in accordance with the second control signal. |
