Parallel Input Series Output Ultra-High Step up DC/DC Converter With Three Degrees of Freedom

In this article, a new high step up dc/dc converter with a very high voltage gain is presented. The proposed converter employs coupled inductors and built-in transformer to achieve an ultra-high voltage ratio with low duty cycle of switches. Interleaved structure of the proposed converter minimizes the input current ripple, and due to the input current sharing, the current stress of switches is reduced. Low voltage stress of switches make it possible to employ low on resistance power mosfets. In the proposed converter, the large output voltage is stored in two series capacitors, which reduces the cost and capacitor losses. The employed clamp circuit not only recycle the energy of leakage inductance but also improve the voltage gain. Thanks to all of these mentioned features, power loss reduces and the circuit performance is improved. In order to verify the validity of theoretical analysis, a 1-kW laboratory prototype circuit converting 26 to 450 V is implemented.