Bidirectional photovoltaic inverter based on high-frequency legs

Abstract

The invention relates to a bidirectional photovoltaic inverter based on high-frequency legs. The inverter is characterized by comprising at least one forward high-frequency N-cell leg, at least one backward high-frequency N-cell leg and two power-frequency P-cell legs in parallel connection, wherein each forward high-frequency N-cell leg is connected with one inductor to be used as the anode output end of a power supply, and each backward high-frequency N-cell leg is connected with one inductor to be used as the cathode output end of the power supply; and each forward/backward high-frequency N-cell leg is formed by connecting a diode with a high-frequency switch in series, and each power-frequency P-cell leg is formed by connecting a diode with a power-frequency switch in series. The inductors whose currents work in positive half waves are mutually coupled, and the inductors whose currents work in negative half waves are mutually coupled. The bidirectional photovoltaic inverter can be switched between a photovoltaic mode and an energy-storing mode at random, the size of the inverter is small, problems in direction connection can be avoided, current leakage can be effectively inhibited, the system frequency is increased, bidirectional power control is realized, and the capacity is easy to increase.

Description

technical field [0001] The invention relates to photovoltaic power generation inverter technology, and is a bidirectional photovoltaic inverter based on a high-frequency bridge arm. Background technique [0002] With the increasingly serious problem of energy shortage in the world, the energy problem has become a major basic problem facing mankind in the 21st century. The development and application of clean and renewable energy has attracted more and more attention from all countries in the world. In recent years, photovoltaic power generation technology has been continuously developed, and photovoltaic grid-connected power generation has become one of the main ways to utilize solar energy. The transformerless photovoltaic inverter is more and more popular all over the world because of its small size, light weight and high efficiency, and many transformerless inverter structures have appeared. [0003] Such as figure 1 As shown, the existing typical bridge arm structures ...

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Problems solved by technology

The existing problems of these structures: 1. The problem of direct connection, the dead time needs to be set, which reduces the system efficiency; 2. The current ripple is large, and the inductance value and volume of the required inductor are large; 3. It cannot be used completely. frequency switch, the system frequency cannot be increased; 4. The circuit cannot realize power bidirectional control; 5. The circuit cannot simply expand the capacity; 6. The circuit cannot work well in the DCM state

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