Research On Control Strategy For Dual-mode Inverter

In the background of a global energy crisis,new energy has attracted more and more attention around the world,and distributed power generation systems are made up of new energy has been widely used and studied.Grid-connected inverters as a connection bridge between the grid and distributed generation systems,is the key parts of the new energy power generation,requiring them to work in stand-alone mode for local load power supply and in grid mode transfer energy back to the grid.Therefore,for dual-mode inverter switching process research is of great significance.In this paper,by studying the grid / independent dual-mode inverter,designed its system control method,and on this basis to study the seamless handoff of dual-mode control strategy.In this paper the structure of dual-mode the Inverter circuit is analyzed and its mathematical model is derived,laid the groundwork for behind the system controller design,and introduces the principle of Space Vector Pulse Width Modulation technique,and the inverter output filter parameters are designed.Then according to the different dual mode inverter control objects designed different control methods: in stand-alone mode,and inverter is equivalent to a voltage source,the use of voltage and current double closed loop control method;in grid mode,and inverter is equivalent to a current source,the use of direct current control method.Also the voltage and current double closed-loop of parameters have been designed and three phase software phase-locked technology has been researched.Analyzes the dual-mode inverter voltage mutation causes and seamless grid inverter switching strategy is studied.Design seamless switching control strategy based on the current,voltage controller switching and steps for implementation.Since the method based switching controller,before switching control structure has changed,the circuit is also more complex,seamless handoff algorithm based on indirect current control has been studied and designed grid inverter voltage amplitude and phase decoupling control method.Seamless handover algorithm under indirect current control achieved controller unification,can better achieve the load smoothing over,and simulation to verify the two seamlessly switch algorithms.Finally,the main circuit of the system has been designed,and built hardware test platform,designed the control circuit using ARM controller as the core,explained the various parts of the control circuit.And to verify the validity of seamless handover control method related experiments are carried out on the platform.