Performance improvement of three phase rectifier by employing electronic smoothing inductor

An electronic smoothing inductor (ESI) is very attractive circuit topology to improve power factor and to reduce the total harmonic distortions (THDs) of the ac mains current in a three phase diode bridge rectifier. The ESI reduces the low frequency ripples and controls the intermediate dc-link voltage to a dc value and peak value of the mains current also reduces. The ESI performs the function of an inductor that has controlled impedance. When compared to a passive filter, the ESI offers a filtering solution that is significantly smaller in size. This, in turn, helps in increasing the power density of the rectifier. In case of an inverter connected to the output of the rectifier, peak to peak voltage ripples to the front end of the inverter reduces significantly by the ESI, and it increases lifetime of the capacitor connected to the dc link and reduces the voltage stress of the active power semiconductors of the inverter. In this paper, an average model of the ESI and its control schemes are presented.