| 摘要 |
PURPOSE:To smoothly operate an inverter and another AC power source without moving parallel switches, by a method wherein the ideal output voltage of output which is to be generated from the inverter is set to be of a voltage actual-value, and wherein the voltage of the other AC power source is set to be of a voltage desired-value, and wherein a voltage regulating means is operated so that a deviation between the two values may be zero. CONSTITUTION:Bus line voltage is set to be of a desired value, and the output of a multiplier circuit 16 is set to be of an actual value, and the input of a deviation between both the values to a voltage regulating circuit 14 is provided. When the main circuit of a PWM inverter 3 is worked, a pulse width modulation controlling circuit 15 to which the input of control signal from the voltage regulating circuit 14 is provided is in a state that the output voltage can be permitted to coincide with the bus line voltage. When both the ones coincide with each other, then the output of an inverter circuit 17 is turned into zero, and this is detected by a voltage coincidence detecting circuit 18, and voltage coincidence signal is transmitted to a logical circuit 19. By the pulse width modulation controlling circuit 15, the sine waveform of output to be generated from the PWM inverter 3 and the bus line voltage of a sine wave from a bus line voltage detecting circuit 11 are conducted to a phase difference zero detecting circuit 20, and when phase difference zero is detected, then signal is transmitted to the logical product circuit 19. |
