| 摘要 |
PROBLEM TO BE SOLVED: To prevent the appearance of the current flow-in or flow-out by means of error component of the inverter voltage while a small-capacity PWM inverter is being operated in a self-excited reactive power compensating device which has a large-capacity rectangular-wave inverter and the small-capacity PWM inverter. SOLUTION: Only when the DC voltage EF of a DC capacitor 12 of a small- capacity PWM inverter becomes the same as or larger than a set value EFREF, a negative power control signal 'k' to correspond to an error component of the inflow inverter power is found. Only when an effective value of the rectifier current IR becomes the same as or larger than a set value IRREF, a positive power control signal 'k' to correspond to an error component of the outflow inverter power is found. Then, an amplitude adjustment signal kICREF which is obtained by multiplying a compensating current command value ICREF by the positive or negative power control signal and an output current control signal VI are added to obtain a final output voltage command signal VFREF and on that signal, the appearance of an error component of the inflow and outflow inverter power during operation of an inverter is prevented. |
