CONTROL METHOD FOR SELF-EXCITED REACTIVE POWER COMPENSATION APPARATUS

摘要

PROBLEM TO BE SOLVED: To obtain a control method in which the DC voltage of a PWM inverter can be stabilized. ;SOLUTION: In a self-excited reactive power compensation apparatus, a square-wave inverter and a PWM inverter are connected in series. In the self-excited reactive power compensation apparatus, the difference (VS-VB') between a system voltage VS and the output voltage VB' of the square-wave inverter is used as a correction voltage signal VH' so as to control the PWM inverter. At this time, on the basis of the DC voltage VDC of the square-wave inverter, the amplitude |VB'| of the output voltage VB' of the square-wave inverter is detected, and the amplitude |VS| of the system voltage VS is detected by a full-wave rectifier circuit 22. Then, the difference (|VS|-|VB'|) between the amplitude |VS| of the system voltage VS and the amplitude |VB'| of the output voltage VB' of the square-wave inverter is computed by a subtracter 24, it is multiplied by a reference square-wave signal (v), synchronized with the system voltage VS, by using a multiplier 25, and the correction voltage signal VB' is obtained. The correction voltage signal VH' is added to a control voltage signal V_ref1 by using an adder 26, and a control voltage signal V_ref' which is given to the PWM inverter is obtained.;COPYRIGHT: (C)1997,JPO