The Research On Power Inverter Devices For Distributed Generation System

With the development of the economy, the demand for electricity is growingrapidly. For the traditional centralized power generation and large-capacity powertransmission, traditional generator sets exist huge security hidden dangers. With thedemand for energy is increasing, people pay more attention to the rational use ofcheap and non-polluting energy such as solar and wind. Distributed generationsystems is close to the load side, and it is available to users relying on co-generationgas turbines, diesel generators and wind energy and solar energy. Distributedgeneration system has the advantages of less investment, the use of flexible, it canapplies to the remote area and region that the power grid can not cover. However,because it belongs to the micro-grid, a limited power supply system, it mayencounter voltage serious sag when the load changes suddenly, which affects thequality of power supply. To solve the above problem, this paper make a study ofpower inverters for distributed power generation and analysis its control strategy.Firstly, this paper analyzes the working princ iple of the Inverter device and themain circuit topology for distributed power generation, then creates themathematical model of the invter，make a study of phase-locked loop technology,and three-phase phase-locked loop based on dq transformation is achieved. Outputcharacteristics for distributed generation systems, the inverter device controlstrategy analysis. In this part, lock loop and instantaneous electric current detectionscheme are designed, then the invter device’s control strategy is researched, whichadopt current inner loop control based on feed forward decoupling and voltageoutside loop control method. Then Use MATLAB Simulink tools to build simulationmodel and simulate distributed power generation characteristics, and energy iscompensation according to the characteristics. The feasibility of the compensationcontrol strategy was verified. Simulate the energy compensation when voltage dropson the basis of the analog output voltage characteristics of distributed generationsystems, and the simulate result verify the rationality of the control strategy.Secondly, the power circuit and control circuit of the inverter device aredesigned in detail, inc luding signal detection circuit, drive circuit and the auxiliarypower supply, and a model machine of100kW is also made. With the core controlcomponent of TI’s TMS320F2812, the software programming realized SVPWMmodulation, over-pressure over-current protection and incremental digital PI controlalgorithm.Finally, the experimental platform which simulate the characteristics ofdistributed power generation is established, and the power inverter experiment isalso done. Through the experiments, the inverter device’s working principle is verified. The experimental results show that the power inverter device caneffectively suppress the voltage drop, and improve the quality of the distributedpower grid. So the inverter strategy of this system is correct and design idea is reallyfeasible.