Research On The Control Of PWM Recetifier In Asymmetry Power System

PWM recetifier is an important device for energy conversion,which is Widely used in industrial equipment. It is unusual for common Controlled PWM Rectifier to think more about unbalanced three phase voltage, which limited the application of PWM rectifier. In order to inprove the PWM recetifier factor under unbalanced input voltage, The positive and negative sequence current control strategy based on TMS320X 2808 is proposed to improve system efficiency .First of all, The article focuses on the Three-phase system structure, And one detailed analysis of the mathematical model of three-phase rectifier is given.if we Ignore the switching loss, the input power and output power are analysised.and a positive and negative sequence current control strategy is proposed, On the analysis of vector control, we know the realationship between the system power inverter vector and control vector. Based on the theory above, we are ready for simulation and implementation.In order to get the message of voltage and current, the fastest dynamic response is calculated from the signal delay, On the analysis of the system, a feedforward decoupling algorithm is proposed to lift the coupling between positive and negative sequence current,while lifting the same coordinate system d, q current coupling. All of the method aboved get one aim-linear control.with the Computer Aided Techniques,This strategy is verified by SIMPLORER /Simulation 7.0 .In the simulation, input power,bus voltage, and dynamic response are compared between the positive and negative sequence current control strategy under unbalanced voltage and the normal strategy under unbalanced voltage. At the same time Inversion process is simulated under un balanced voltage.Finally, the hardware and the software of grid-connected PV system is given, including the choice of the key parameters of main circuit and the design of the control circuit and the process of software. At the same time, the rectifier control strategy and the method of inverter control strategy are given. Some problems of control process are illustrated and feasible solution is proposed.The experiment results proves the validity and feasibility of the research on the control of PWM recetifier in asymmetry power system in this thesis.