A kind of interleaved non-isolated high step-up DC/DC converter is presented in this study. The converter consists of two basic Boost cells and some diode-capacitor multiplier (DCM) cells as needed. Because of the DCM cells, the voltage conversion ratio is enlarged and the extreme large duty ratio can be avoided in the high step-up applications. Moreover, the voltage stress of all the power devices is greatly lower than the output voltage. As a result, lower-voltage-rated power devices can be employed, and higher efficiency can be expected. Since the two basic Boost cells are controlled by the interleaving method, which means the phase difference between the two pulse width moderlation (PWM) signals is 180°and the input current is the sums of the two inductor currents, the input current ripple is decreased and the size of the input filter could be reduced, which make it a suitable choice in the photovoltaic power generation system and hybrid electric vehicles, etc. Finally, the experimental results from a 300 W, 30-400 V laboratory prototype are presented to validate the effectiveness of the proposed converter.

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To obtain sufficient luminance and achieve higher reliability, light-emitting diodes (LEDs) are usually arranged in parallel strings in many high-power applications. Since current imbalance should be avoided among the parallel LED strings, a multi-channel constant current LED driver based on high-frequency AC bus is proposed in this study. The proposed driver is composed of one resonant inverter followed by passive resonant rectifiers according to the number of LED strings. The amplitude of the high-frequency AC bus voltage is regulated by the resonant inverter and each LED string is individually powered with constant current by its corresponding passive resonant rectifier. The proposed driver is characterised by low cost and high efficiency. Finally, a prototype is built to verify the performance of the proposed driver.

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