A Novel ZVS Step up Converter for Renewable Energy Generation Applications

Abstract

This paper introduces a novel ZVS step up converter especially for renewable energy generation applications. The proposed converter is consisting of single switch which operates in zero voltage and zero current. Resonant principles are opted for soft switching. High voltage gain is obtained by switched capacitor cell topology.Use of single switch will reduce the cost of conversion and complexity of control circuits. The circuit topology consisting of resonant inverter with zero voltage switching with an energy blocking diode having zero current switching. The energy blocking diode with DC output filter filters the output stage of converter. KEYWORDS:Switched capacitor, Resonant power converter, zero-current switching, zero-voltage switching, pulsewidth modulation I.INTRODUCTIONNow a days, global surface temperatures have increased drastically, because the global warming is taking place due to effluent gas emissions and increases in Carbon Monoxide. To prevent these effects, some potential solutions have evolved including energy conservation through improved energy efficiency, a reduction in fossil fuel use and an increase in environmental friendly energy sources. However, the output voltage of these sources is too low and which requires a voltage boost. In this stage, efficiency of conversion is a major concern. Efficiency in the sense minimizing the switching and conduction losses. II.LITERATURE SURVEYIn transformer isolated dc-dc converters, by increasing the turns ratio, we can boost the voltage gain. But, when we increase the turns ratio, leakage inductance will also increase, which will lead to high voltage stress and poor efficiency [1].In case of non-isolated dc-dc converter topologies, boost converter is using for voltage boost up. But duty cycle limitation is the problem associated. As duty cycle increases, inductor current ripple and turn off current of the power device will increase, which leads to large conduction loss and degraded efficiency [ 2 ]. Cascaded boost converters can increase the voltage gain, however component count will increase hence size and cost of converter also [3]. Integrating coupled inductor into the non-isolated dc-dc converter by choosing a suitableturns ratio can increase the voltage gain effectively. In order to absorb the energy stored in leakage inductor, a snubber circuitry is needed which will increase circuit complexity and loss of efficiency [4]. Switched capacitor cell converters can obtain a very high voltage gain, however input current pulsation is a problem and poor load and line voltage regulation. Incorporating switched capacitor structure into switching mode dc-dc converter is a good remedy for this problems. Hence we can dramatically increase voltage gain with an appropriate duty cycle with good voltage regulation and minimum input current pulsation [5].Pulse width modulationis the simplest method for controlling power semiconductor switches.PWM power converters can now operate at a much higher switching frequency hence reducing the size of passive co...