Control strategies of active power line conditioners in single-phase circuits

This paper deals with two control strategies for the active power line conditioners in single-phase circuits. The first one is a constant dc capacitor voltage control based strategy, which is commonly used in the active power line conditioners. Any detection blocks of the fundamental active, reactive, and harmonic components are not necessary in this method. Thus we offer the simplest way to compensate the fundamental reactive and harmonic currents on the source-side. The other is a reactive power control based strategy, which is with the correlation and cross-correlation coefficients between the feeder voltage and load current. Controlling the detected fundamental reactive component with the cross-correlation coefficient on the source-side reduces the capacity of the PWM inverter, which performs the active power line conditioners. The basic principles of the proposed control strategies are discussed in detail, and then applied to the single-phase active power line conditioners in single-phase based distribution systems. These sigle-phase distributin systems are used in the single-phase three wire systems and electrified railways. The validity and excellent practicability of the proposed control strategies are confirmed by experimental results.