Dynamic Modeling For Photovoltaic And Wind-Power Generation Systems

The world is developing renewable energy because of energy shortage and environment pollution right now. Photovoltaic (PV) electricity and wind electricity is the main form to use renewable energy. Electromagnetic transient modeling of PV generation system and wind generation system is useful to study control strategy, select parameter, analyze and depress electrical harmonic etc. The electromechanical transient model is the simplified form of electromagnetic transient model. It can reflect the main characters of the generation system. It can be used at studying the correlative impression between renewable energy generation system and the main grid, dynamic stabilization, the electrical system cooperative control etc.The work of the paper is to study the electromagnetic and electromechanical transient models of PV generation system and wind generation system. The main contents are as follows.(1) The electromagnetic and electromechanical transient models of two stages structure grid connected PV system are studied. A method to get the PV array parameters is established at first. Based on analyzing operation foundation, the electromagnetic transient model is set up. The electromechanical transient model is based on the power character of photovoltaic array, DC/DC convertor and DC/AC convertor. Particle Swarm Optimization (PSO) is used to define parameters of electromechanical transient model according to electromagnetic transient model. The simulation proved the electromechanical transient model reflecting PV generation system transient characters.(2) The electromagnetic and electromechanical transient models of direct-driven wind-power system with permanent magnet synchronous generator (PMSG) are studied. The topology of back-to-back PWM converter is selected to study. The electromagnetic transient model is based on operation foundation. The electromechanical transient model is got by modulating3-orders transient model of synchronous machine. After got the parameters of electromechanical transient model by PSO, the two models have the similar power reflection to the grid voltage change.(3) The electromagnetic and electromechanical transient models of wind-power system with doubly fed induction generator (DFIG) are studied. The electromagnetic transient model is accorded to the operation foundation. Algebraic computation and1-order inertia delay is used instead of electronics function in electromechanical transient model. It found the electromechanical transient model has the similar reflection to wind velocity and grid voltage change as electromagnetic transient model. It also found the stator electromagnetic transient can be neglected if only the wind velocity change is considered.