Designing and analysis of an interleaved boost converter with passive lossless clamp circuits

A new type of high step-up, high efficiency interleaved boost converter is proposed in this paper. Coupled-inductors are used in this topology to extend the duty cycle. Therefore, the low-voltage rated and low resistance devices can be applied to minimize the conduction which makes the conduction losses significantly reduced. ZCS turn-on is achieved by the intrinsic leakage inductance of the coupled inductors so that the switching losses are reduced and the power density can be improved. The clamp mode passive lossless snubber is applied in this converter which makes this topology less complicated and more reliable compared to those using the active-clamp scheme. The clamp circuit recovers the leakage energy and eventually releases to the load which improves the efficiency further. Due to the current decreasing rate of the output rectifier controlled by the leakage inductance, the diode reverse-recovery problem is alleviated. Furthermore, interleaved clamp mode makes the load current auto-shared by each phase without additional current sharing module needed. The experimental results based on a 48 V to 380 V DC/DC prototype verify the effectiveness of the theoretical analysis.