Dynamic response optimization for interleaved boost PFC converter with improved dual feedforward control

Abstract

To reduce the current loop reference distortion in traditional average current control and total harmonic distortion of line current, this paper employs improved average current control (IACC) of Boost PFC, in which a digital-generated unit sinusoidal half-wave (USHW) is introduced as current loop sinusoidal reference. Aimed at generating USHW with DSP's enhanced capture module correctly and conveniently, a fault-tolerant algorithm is proposed. Based on IACC, an improved dual feedforward control (IDFC) including input and load feedforward is proposed to optimize dynamic response. Peak voltage prediction is used to further improve IDFC's performance. Load and input detection are also introduced to enable IDFC only when load or input is in transient process, which significantly reduces calculation cycles and prevents second-order harmonic from being introduced into the control loop by IDFC in stable state. As a result, ability of suppressing input and output disturbances and rate of phase-shedding are promoted. The proposed control strategy is verified on a 1.3kW prototype.