The Topology Optimization And Design For Three-phase Interleave DC/DC Converter

Solar energy is one of clean, highly-efficient resources. It is pollution-free, renewable and not limited by regions, so it has been quickly popularized and applied. Because of the world energy crisis and environmental deterioration, it is vital to develop and utilize the renewable sources (for example:solar energy) for sustainable development. With the development of solar cell and power electronics, photovoltaic power generation has become to a main way of utilizing new energy resource. Photovoltaic system consists of solar cell, dc/dc converter and inverter.At present, the single-phase full-bridge converter is the dominant topology in high power dc/dc applications. Although multiphase converters have been proposed, most of them are used in high input-voltage, low input-current systems, which is not suitable for a low voltage, high current system such as photovoltaic system. This paper analyzes a novel three-phase six-leg dc/dc power converter used in low input-voltage, high input-current system. Power rating of the converter is increased by multiphase interleaving, not by multiple devices in parallel, and its transformer isΔ-Y connection, so it can double the output voltage and lower the turns-ratio of transformer. Because of the interleaved control, the frequency of output voltage is six times higher than the frequency of switches, so the size of output filter can be reduced.This dissertation also analyzes the model of the dc/dc converter and gets the transfer function between control degree a and output voltage Vout. This paper discusses the parameters design of single voltage loop control, inner current loop-outer voltage loop control and voltage loop with current cut-off feedback, and simulates the circuit of three control methods by PSIM software. the dc/dc converter under inverter-load condition is also simulated, through control method of voltage loop with current cut-off feedback. Finally, according to parameter design and simulation results, several parts of the hardware designs are analyzed...