Two Stages Of Photovoltaic Energy Hybrid Control Technology Research

Energy shortages and increasingly serious environmental pollution, development and utilization of new energy sources has become a hot research in various countries, particularly in the field of distributed generation. Currently, distributed generation will have an impact and negative impacts to power system, in order to coordinate distributed PV systems on the grid to bring the pros and cons, micro-grid systems become a national hotspot. Microgrid system not only bring economic benefits to give users, but also to improve the reliability and flexibility of power system operation. In order to meet the needs of domestic and international PV market, with two-stage hybrid photovoltaic energy storage control technology as a research object, designed as a power electronic conversion device hybrid inverter, from system topology, model analysis, control strategy, switching aspects of strategy, a detailed analysis of the two-stage hybrid photovoltaic energy storage technologies.First, the actual micro-grid power interface functions and technical needs, select the appropriate inverter topologies, and explains hybrid inverter works, according to the system operating environment and function, design work status. Analysis of micro-grid systems research focus, combined with common islanding detection method, designed for hybrid inverter periodic disturbance AFD islanding detection methods and analysis for the grid-tied and off-grid mode switching strategies.Second, the system structure is divided into the preamp DC converter and the second stage inverter, and were studied control program. First establish Buck converter small signal model is applied to verify the feasibility of the preamp DC buck and design control scheme to solve three-level converter Buck partial pressure equalizing capacitance problem; the preamp applied to the photovoltaic system design MPPT control strategy, based on the perfect pre-control strategy, complete simulation. The second stage inverter analysis like the previous level, according to the model of analysis works, design the output filter, perfect the grid-tied and off-grid mode control strategy, in the grid-tied mode as a current source, the use of the current inner Join the bus voltage control loop, the bus voltage loop output current setpoint control grid-tied feed or rectified charging when off-grid model as a voltage source, the use of the instantaneous output voltage outer plus inner current loop control strategies, achieve stable power supply to the load, combined mode switching strategies to achieve simulation.Finally, on the basis of the above study, the design can be applied to micro-grid systems hybrid inverter; detailed system design performance, combined with 2KW inverter hardware platform, control system design software, and complete the two-stage protection, ensure the safety of the platform, verify that the above design control strategies, and to focus on a detailed analysis of the experimental waveforms, concluded. After completing the above tasks, summing up the work process and results, For the uncomplicated task and the problems, prospects for future research work.