DSP-based closed-loop control of bi-directional voltage mode high frequency link inverter with active clamp

This paper presents a novel modulation and digital controller based on a bi-directional voltage mode high frequency link inverter with active clamp to achieve fast dynamic response and high static performance. The inverter consists of a full-bridge converter, a bi-directional active rectifier, an active clamp branch and a pulse width modulation (SPWM) inverter bridge. A novel modulation strategy is applied by modulating the triangle carrier wave and two inverse sinusoidal modulation waves, it is no need of checking the pole of the output voltage to switch the modulated signals, and it is able to weaken the distortion of the output waveform on zero passage. Double closed-loop digital control with load current feed-forward is applied to achieve good dynamic response. The modulation and control strategy is realized by using the TMS320LF2407A DSP and EPM7128 CPLD. Theoretical analysis and experimental results referring to a laboratory prototype (3 KVA) indicate that the proposed modulation and control scheme are promising for the applications of DC/AC power supply.