The Study Of Proton Exchange Membrane Fuell Cell Power Generation Technology Based On Virtual Synchronous Genertor

Distributed generation system based on new energy, such as fuel cell, is getting more and more attention and occupying a growing proportion in the traditional power system. Every distributed generation has the same inverter-interfaced in distributed generation systems. If we can unify the control strategies of the inverter into a model with the characteristics of synchronous generator, the experience accumulated in the modern power system can be directly used for reference. This thesis established a proton exchange membrane fuel cell power generation with virtual synchronous generator and to verify the characteristics of the system on the island mode and grid connected mode of operation conditions.The thesis is described by the following four parts:1.This part firstly describes the drawbacks of the current power system, but the establishment of distributed power systems is one of the directions to solve these problems. It also elaborates the models, the development and research states of fuel cell power system. Then, it gives the structure of three-phase full-bridge inverter and three commonly used control methods. Finally, it focuses on the analysis of the equivalent and control method for Voltage-Mode virtual synchronous generator proposed by Professor Qingchang Zhong, and proposes the need to build a proton exchange membrane fuel cell power generation technology requirements of the system.2. This part uses semi empirical method to construct the corresponding simulation model, including the stack voltage model, fuel flow model, simplified dynamic analysis model and the equivalent model of the peripheral equipment. Then it draws the corresponding static characteristic curve and the dynamic characteristic curve. Finally it analyses the voltage curve and the power curve of the battery on different temperature.3. This part firstly follows mathematical model and control method of the synchronous motor, and structures that of the virtual synchronous generator, which are the establishment of electromagnetic equations, rotor motion equations, speed control method and exciter control method of virtual synchronous generator. Double inner-loop of PI control is proposed to approach the model of the synchronous generator,which is current loop instead of voltage loop because of corrupt practices. And the thesis also gives the key parameter selection method of the control strategy and the design method of filter parameters for the circuit. It gives the schematic and ideas in the design process of the virtual synchronous generator control circuit, including main control board, extended board, switchable board, driver board, sampling board and display board. It briefly introduces the basic thought of the control software programming.4. This part builds the simulation of virtual synchronous generator control on the island mode and grid connected mode of operation conditions to verify the consistency between virtual synchronous generator and the synchronous generator. it also completes the simulation of proton exchange membrane fuel cell power generation based on virtual synchronous generator which can work in the island mode and grid connected mode of operation conditions. It comes out that the rotational inertia of VSG can help to eliminate the overshoot of the output voltage, current and power caused by DC converter.