Isolated switched-boost push-pull DC-DC converter for step-up applications

A high voltage ratio DC-DC converter is proposed which is comprised of four stages. First, an impedance network along with a switching network have been used to boost the input voltage. The boosted voltage waveform is then followed by an isolation transformer to provide another degree of freedom and obtain higher boost ability. Finally, a voltage multiplier rectifier is utilised to rectify the secondary voltage of the transformer. No switching dead-time is required, which increases the reliability of the converter. The proposed converter benefits from the continuous input current. Besides, a comparison with the existing step-up topologies indicates that the number of passive elements and hence the weight and size have been reduced. The operating principles were analysed and the experimental tests on a 260 W prototype reveal that a high efficiency above 91% can be achieved