Study Of Photovoltaic Pump System Based On Z-source Inverter

After decades of development, the photovoltaic pump (PV pump) system has become an important part of solar energy applications. This paper focuses on how to enhance its efficiency and reliability.Considering the problems of the main circuit of traditional photovoltaic pump system, method of improvement are researched and a new Photovoltaic Pump System based on Z-source Inverter is presented.In this paper, the operating principle of the Z-source Inverter is described firstly. Then the devices voltage and current stress is analyzed. At the same time, the control method of the system is discussed. Also, the main circuit parameters are designed. Finally, the simulation results have been performed to confirm the theoretical analysis. The main aspects of this dissertation are summarized as follows:1. The topology and operating principle of voltage-Z-source Inverter are analyzed in detail, and its discontinuous mode of current that may exist is explained.2. The control methods of Z- source Inverter applied in Photovoltaic Pump System are focused on .And two close loops of Photovoltaic Array and Z-source -capacitor voltage is given out according to the circuit structure and control objectives.3. The various PWM control strategies of Z-source Inverter are discussed, as well as strategies applied in Photovoltaic Pump System. The operating range and devices voltage and current stress are given out, which offers a theoretical authority to the design of the main circuit of Z-source Inverter.4. Analyzing and summarizing the maximum power point tracking (MPPT) control method. The CVT algorithm and TMPPT algorithm are mainly introduced, the control block diagrams are given for MPPT, achieving power optimization.5. The main circuit parameters is designed to meet the needs of engineering design. Finally, in order to verify the correctness of control strategies, the system model is built .The simulation results correspond to the theoretical analysis.