A New Digital Control Algorithm for Dual-Transistor Forward Converter

In this paper, a new digital control algorithm is presented to improve the dynamic performance of the dual-transistor forward converter (DTFC) during a transient event. The algorithm uses a linear control scheme under the stable-state condition and the charge balance control scheme under the transient condition. Based on the principle of capacitor charge balance, the proposed algorithm predicts the switch over time to achieve optimal transient response for a DTFC, thus the minimal voltage derivation and recovery time are achieved when the load current has a step change. Compared with a conventional voltage mode controller, the proposed algorithm provides a much better dynamic performance. Furthermore, simulation and experiment results demonstrate the effectiveness of the algorithm.