| 摘要 |
PROBLEM TO BE SOLVED: To stabilize power feeding voltage of load by adding a frequency command to an input of a carrier frequency arithmetic unit of a PWM inverter consisting of a power converter for inputting a switching pulse. SOLUTION: A carrier switching signal SW1 to be input to a carrier frequency arithmetic unit 7 switches a carrier frequency constant mode and a carrier synchronization mode. A switching pulse G is given to a power converter 9 to control the speed and the torque of an inductor 2. A carrier frequency fc obtained by the differentiation of control phase angle θ PI in fine vibrating condition vibrates in turn in the large vibrating condition to make unstable the voltage supplied to the PWM inverter load with an output d of a vector control means 1 is calculated from the d-axis voltage command and q-axis voltage command. Therefore, a carrier frequency arithmetic unit 7 inputs a frequency command ω* for arithmetic operation of fc=n.ω*/4π (n is a ratio with a half-period carrier of the modulation coefficient command), in order to obtain the stable carrier frequency fc in the carrier synchronous PWM control. |
