Research On Current Converter Based On Current - Mode Multi - Level Photovoltaic

Solar energy as a huge amount of renewable, non-polluting and clean energy, has been widely used instead of the current fossil fuel which is one of main energy. Solar energy is the development trend of future energy, therefore, the development and utilization of solar energy is very meaningful.The input of the photovoltaic inverter is photovoltaic panel, its output power is closely related to the environment temperature and illumination. In order to use the photovoltaic cells efficiently, a current variable-step conductanceincrement MPPT(Maximum Power Point Tracking) algorithm by analyzing the principle of the photovoltaic cells and comparing the commonly used voltage-type MPPT algorithm. In addition, the operational principle of single-phase 5-level current-source inverter is analyzed, POD-PWM control technology is implemented under the condition of open-loop and closed-loop control respectively, and the control effect between the open-loop and closed-loop control is analyzed and compared.Finally, the entire photovoltaic inverter system is modeled and simulated based on PSIM, the experimental prototype is set up. The experimental results show that under different environmental conditions, the MPPT algorithm can operate at the maximum power point, which effectively improves the utilization efficiency of photovoltaic cells. Under the open loop control of the converter, inductor current is unstable; in closed-loop control case, the inductor current can achieve a good balance. The inverter output current can achieve sinusoidal wave, inverter power factor is close to 1.