Study On The DSP Control System Of The Grid-connected Inverter For Wind Energy Conversion System

Wind energy due to its clean and renewable character has developed rapidly in recent years and ranks as one of the most promising renewable energy resource. This dissertation is a part of the project of developing MW-level Wind Energy Conversion System which is a key 863 program. It is mainly about the wind energy conversion system with a rated output of 1.2MW which applied to the variable speed constant frequency wind energy system (VSCF). The focus is on the control method of the inverter in the electrical energy conversion system.This paper first generally describes the wind energy conversion systems, and introduces the developing status and the technological development trend of wind power both in China and abroad. Nowadays high-level power direct-drive and gear-drive are the two main wind power generation technology. It utilizes the AC-DC-AC conversion configuration to deliver the high-level power energy from permanent-magnet generators to the grid, the power rating is 1.2MW. The absence of gearbox and less maintenance required makes this constitution having more developing forefront.In the second chapter of the dissertation, it firstly introduces the aerodynamic force characteristic of the wind turbine, and describes different control strategy of wind turbine in different wind speed. Then it mainly talks about the two VSCF technologies, the direct-drive and gearbox/induction generator technologies, used in wind power generation system.In the power conversion system, the important section is grid-connected. It delivers the power of wind energy in the conversion system to the grid. The focus of this chapter is the main circuit constitution and working principle, and theoretical derivation is given and analyzed.The main circuit parameters of the 1.2MW conversion system are selected through theoretical derivation and calculation, including the DC side capacitors, the grid side inductances, the three-multiple boost inductances, the filtering capacitors behind the diode-bridge rectifier and the grid side filtering capacitors. The switching tubes used in the 3 boost converter and two-multiple inverter are selected. The loss and the junction temperature of these switching tubes are also calculated.The instantaneous current control method is used in the grid-connected inverter. The PI parameters of the outer voltage loop and the inner current loop are determined in the experiment, and the closed loop control experiment is completed.The high speed integrated control chip DSP2407 is the core of control. At the mean time, an experiment platform of wind energy conversion system is constructed and the experimental waveforms are presented and analyzed in this paper.