| 摘要 |
PROBLEM TO BE SOLVED: To obtain a required sine wave PWM control signal which matches the center time of each period of a carrier by setting the width of a sawtooth carrier at the half period of the carrier and a pulse signal having a width which is as broad as a specific multiple of its pulse width, by composing the pulse width by dividing the pulse width to the front and rear sides of the center time of each period of the carrier as the PWM control signal. SOLUTION: A sawtooth carrier signal Vc forms a sawtooth pulse train with a period set to T and a time width set to T/2. The pulse width of each pulse of the pulse train is set at 2to(n-1), 2ton, 2to(n+1) by performing such operation that a signal PWM.S is changed to a pulse having a width of 2ton by dividing the time ton which is obtained by subtracting the operating time lag for preventing the simultaneous conduction of the upper and lower arm switching elements of the main circuit bridge of an inverter from the time tn, until the single Vc becomes larger than a sine wave control signal Vs from a time nT to the front and rear sides of the center time nT+T/2 of periods nT to (n+1)T for each of time (n-1)T to nT to (n+1)T. |
