What is an Active Front End (AFE) and its benefits?

An AFE replaces diode rectifiers with a PWM-controlled IGBT bridge operating as a boost rectifier. Benefits include: unity power factor (no reactive power consumption), bidirectional power flow (allows regeneration to grid), low harmonic current (sinusoidal input current, THD < 5%), regulated DC bus voltage, and controlled inrush. The AFE requires LCL or L filter at AC side for current smoothing. Control uses synchronous reference frame (dq) decoupling. Used when regeneration is needed or harmonics must be minimized.