Design Of Novel Single-phase Single-stage Buck-boost Photovoltaic Inverter

In recent years, with the development of social productivity, and improvement ofpeople’s living standard. The demand for energy is more and more big, however, due toenvironmental problems brought by the traditional energy use, forcing people explore anddevelop new energy. Therefore, like wind, solar, nuclear energy, tidal energy and other energybeing developed and used. These new energy sources have different characteristics, but thesolar energy has attracted the most attention, because of its clean, no pollution, abundant andrenewable. Believe that as advances of technology, reduction of the cost and the government’sstrong support, the solar energy will be used more widely, more efficiently.In order to utilize solar energy, people use photovoltaic arrays absorb solar energy, andconvert it into electricity for people to use, the power generation mode is called thephotovoltaic power generation. Its structure is composed of PV array, DC-DC converter,inverter, filter. The controller play a role of urging PV array works safely, reliably andefficiently, such as tracking the maximum power point of photovoltaic array by MPPTtechnology. Inverter, as an important equipment of photovoltaic, its main task is convert theDC output power of PV array into AC power, thus it is the core of energy conversion andcontrol of Photovoltaic power generation. And through the filter to eliminate the harmonic,get AC power which meet with the public grid requirement, and put it into the power grid.There are a lot of inverter type, each has its own advantages and disadvantages. Projecthope to choose inverter topology which has low cost, high efficiency,wide input range. Wechoose a single-phase single-stage buck-boost inverter, its features include simple structure,less components, low cost, high reliability and high efficiency. Because it is the buck-boostinverter, DC voltage can be higher or lower than the voltage effective value, therebyimproving the DC input voltage range. The novel single-phase single-stage buck-boostinverter have made great progress at reducing power switchs and EMI. In view of theseadvantages, the inverter develop rapidly, and is used more and more widely.Through the study the operation principle and control strategy on a single-phasesingle-stage buck-boost inverter with only3power switches, design detailed hardware circuit, and simulated the inverter under open loop working mode and closed loop working modebased on PSIM simulation software. Through the analysis of the experimental waveform, wecan found that inverter convert50V-300V DC into220V AC, whose phase, frequencycorrespond with grid, completed the inverse function greatly. And the total harmonicdistortion THD is small, it verificate the advantage of the novel inverter, such as wide inputvoltage range, high reliability, high efficiency.