Pre-regulated push pull converter for hybrid energy systems

Current fed push pull converters are widely used in electronic ballast circuits, telecommunication industries and satellite applications. In this work, a current fed push pull converter which can be powered by solar PV or conventional single phase ac supply is proposed. A current fed push pull acts as an isolated boost converter and needs only a single input inductor. To enhance the significance of a buck stage prior to push pull stage, comparison of a current fed push pull converter with that of a buck current fed push pull is carried out. Buck pre-regulator reduces the voltage stress of the push pull switches. In addition, it is sufficient to modulate the width of the pulse fed to buck stage while maintaining the pulse width of the switches of push pull stage constant. In the proposed design, average current mode control is preferred as it has noise immunity and do not require slope compensation. Based on the input ac supply and readings from a 20W solar panel, a 20W, 100V, 0.2A cascaded buck push pull converter is designed and simulated using PSIM. The control circuit for closed loop simulation is obtained using PSIM smart control.