Single-phase series active conditioner active power flow in a harmonic free electrical system during sag and swell events

This paper presents a Single-Phase Active Conditioner, which primal function is regulate load voltage, thus protecting the most sensitive loads from sags, swells, flicker and voltage harmonics. It is constituted by two back-to-back H-bridge converters. One regulates load voltage, the other DC-link voltage. This paper will focus essentially on the active power flow during sag and swell events, in a harmonic free Electrical System. It is shown that, ideally, during a sag or swell event, the active power consumed from the AC mains, is the same that is delivered to the load. It also shows how this is achieved, by analyzing the working principle of the Single-Phase Series Active Converter, and, particularly, the crucial action of the DC link capacitor. The control strategy of the proposed custom power device is also presented in a brief form, for contextualization with the operating principle for the compensation of voltage variation events. Simulation results are presented, showing transient and steady state waveforms of the Single-phase Series Active Conditioner with a purely resistive load. The controller of Series Active Conditioner was implemented on a TMS320F2812F from Texas Instruments. Experimental results are also presented, and for better understanding of the active power flow in the Single-Phase Series Active Conditioner, the implemented electrical system has only a resistive load.