A single-phase non-isolated photovoltaic grid-connected inverter topology

Abstract

The invention belongs to the technical field of power electronic conversion, and particularly relates to a single-phase non-isolated photovoltaic grid-connected inverter topology. The single-phase non-isolated photovoltaic grid-connected inverter topology comprises a photovoltaic direct current power supply V<pv>, a first capacitor C<1>, a second capacitor C<2>, a third capacitor C<3>, a fourth capacitor C<4>, a first inductor L<1>, a second inductor L<2>, a third inductor L<3>, a first diode D<1>, a second diode D<2>, a third diode D<3>, a first switching transistor S<1>, a second switching transistor S<2> and a single-phase alternating current distribution network V<g>. The topology is simple, the first switching transistor and the second switching transistor are complementarily turned on, and a necessary dead zone is added. The current can be interruptedly input through the first diode and the first inductor; the decoupling of the photovoltaic generation power and alternating current grid-connected power can be realized through adjusting the switching frequency; the no-voltage turning on of the first switching transistor can be realized through the fourth capacitor; and throughthe common ground of the alternating current distribution network and the photovoltaic cell panel, the generation of a common mode leakage current can be avoided, and the photovoltaic panel can maintain the maximum power output.

Description

technical field [0001] The invention belongs to the technical field of power electronic conversion, and in particular relates to a topology structure of a single-phase non-isolated photovoltaic grid-connected inverter. Background technique [0002] With the development of science and technology, the depletion of fossil energy and the problems of environmental pollution are becoming more and more serious. Using clean energy to generate electricity, such as photovoltaic power generation, to gradually replace fossil energy generation is one of the effective ways to solve this problem. Since the output power of photovoltaic panels is direct current, an inverter is required to realize photovoltaic power generation and grid connection. Single-phase non-isolated photovoltaic inverters have the advantages of small size, low cost, and high efficiency, and are widely used in small and medium power photovoltaic power generation grid connection. [0003] At present, many different typ...

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Problems solved by technology

However, due to the lack of transformer isolation, there is an electrical connection between the photovoltaic panels and the AC grid, making single-phase photovoltaic grid-connected inverters generally have the problem of common-mode leakage current, which is not conducive to the improvement of efficiency

For the problem of common-mode leakage current, there are mainly two solutions. One is to use bipolar SPWM modulation for single-phase full-bridge inverters to eliminate common-mode leakage current, but it is not conducive to improving conversion efficiency; the other is Improving the topology to eliminate common-mode leakage currents, but most of these methods require the addition of additional components, increasing cost and size

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