Three-phase four-wire three-level photovoltaic grid-connected connection inverter and control method thereof

Abstract

The invention relates to a three-phase four-wire three-level photovoltaic grid-connected inverter and a control method thereof. In the inverter, voltage input from a solar panel is filtered by a filter capacitor; the input voltage is boosted by a boosting circuit to form direct-current bus voltage serving as input voltage of a post inversion circuit; the bus voltage is inverted by a three-phase four-wire inversion circuit to form three-phase voltage; after being filtered by a filtering circuit, the three-phase voltage is output to a power grid; a controller detects the voltage and output current of the solar panel, the three-phase voltage of the power grid and three-phase current output by the three-phase four-wire inversion circuit; a boosting converter and an inversion controller in thecontroller 101 respectively generate driving pulses of the boosting circuit and the three-phase four-wire inversion circuit to control the operation of the integral inverter. A three-phase four-wire power supply system is formed by the addition of a neutral line, so the inverter can be connected with symmetrically-balanced three-phase loads, and also can be connected with single-phase loads. The application field of the photovoltaic inverter is broadened while the safety of the power supply system is improved.

Description

technical field [0001] The invention relates to a three-phase four-wire three-level photovoltaic grid-connected inverter and a control method thereof. Background technique [0002] With the improvement of people's living standards and the technological progress of society, electric energy has become an energy source that people must rely on in their daily lives. However, primary energy sources such as coal and oil are decreasing day by day, and when people use them, they also cause huge pollution to the environment. The fundamental way to solve the energy problem is to develop environmentally friendly renewable energy, of which solar power generation is an important development direction. [0003] Renewable energy can be divided into two major application areas: one is large-scale grid-connected power stations, and the other is small-scale user-side self-generation and self-use occasions. For these two applications, most commercial photovoltaic inverter products are mainly...

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Problems solved by technology

[0011] The current technical research and patents have a lot of research on three-phase three-wire and singl...

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