| 摘要 |
PURPOSE:To obtain a PWM signal generator of an inverter which is facilitate in the synchronization of an inverter frequency with a carrier frequency by composing a PWM control circuit of all digital elements, thereby simplifying the entire circuit configuration. CONSTITUTION:An inverter frequency command (f command) applied in a binary value is converted by a frequency converter 7 into a clock A of frequency proportional to the value, and input to a ring counter 8 and a frequency divider 9. The prescribed value is set in advance in the counter 8, and the counting operation of the clock A is repeated with the value as one period. Phase information A obtained from the counter 8 is applied to memory cells 10, 11, a calculation is further performed in the first calculator 12, various control data are output. The divider 9 divides the clock A on the basis of the output data to output a clock B. The carrier frequency and the inverter frequency are switched by switching the dividing frequency ratio of the divider 9 and the set value of the counter 13. |
