Control strategy for com-leg in single-phase transformerless three-leg Unified Power Quality Conditioner

Abstract

Single-phase three-leg Unified Power Quality Conditioner (UPQC) is relatively a good choice for power quality compensation in low-power applications as it can achieve high performance with low cost. In this paper, a decoupling control method is proposed to eliminate the interaction between the series and shunt converters of the three-leg UPQC. In the proposed method, output voltage of the common leg is controlled proportional to the grid voltage and the proportional coefficient is optimized to ensure the compensation of both the series and shunt converter with lower DC-link voltage. Additionally, theoretical analysis and certain design criterions are provided in the paper. Simulation and experimental results are also presented to verify the feasibility and effectiveness of the proposed decoupling control method.

Single‐phase universal active power filter based on ac–dc–ac converter with eight controlled switches

“…The conventional single‐phase UAPF (Fig. 1 a ) usually uses a converter with eight controlled switches, but it is also found in the literature topologies that use three legs [11, 15, 19, 20] (six controlled switches) and half‐bridge topologies [11, 21] (four controlled switches). Topologies with six and four control switches were introduced in [6] for current and voltage harmonic compensation, sag/swell compensation, and are considered for low‐power and low‐cost applications.…”