A neutral current electronic compensator

This paper presents a neutral current electronic compensator. It is implemented with a four-wire three-phase PWM voltage converter connected to the AC mains with accessible neutral. The AC mains neutral is connected to the middle point of the converter DC side capacitors. The converter AC currents are controlled with a generalised space vector based hysteresis controller in the /spl alpha//spl beta/0 coordinate system. The AC mains neutral currents are determined and injected by the PWM voltage converter. Consumer's unbalances that may result in a first harmonic neutral current can thus be compensated. Zero sequence harmonic currents caused by single-phase rectifiers and other electronic appliances can also be compensated.