Due to the attractive characteristics such as low cost, simple, and reliable structure, high efficiency, and low EMI noise, three-phase diode rectifier front-end converters have been widely applied to AC-AC power conversion applications such as ASDs and UPS. However, one of the undesirable features of the diode rectifier front-end converters is the greatly distorted line current, which may cause harmonic pollution in the power system. Usually, there are two solutions to solve this problem: One is using the “green” active PFC converters to replace the diode rectifier front-end converters; the other is applying the active power filter technique to compensate for the harmonic current generated by the diode rectifiers.