System Design Of The Medium-Power Charger And Inverter For Off-Grid

Inverter with analog control has been very mature now.And with the development of digital signal processor(DSP),digital control of inverter is rapidly developing in recent years.Digital control has the advantages of versatility,flexibility of control and easy replacement,etc.So that the digital control is the main direction of the inverter.Due to the power has only the function of inverter can no longer meet the current demand for power supply,this paper is designed a power supply with the functions of charge and inverter.The paper analyzes the requirements of the system,determines the design specifications of the system,and give the overall structure of the system.Including the system power supply circuit topology,charging circuit topology and inverter circuit topology.Then the hardware design of the system is given,including the selection of the key components,the parameter calculation of the transformer,the design of the sampling circuit and so on.And in the light of the selection of components package,design the PCB circuit board,and make a experimental prototype for testing.And the article also introduces the existing SPWM analog and digital realization scheme and determines the inverter realization method of the system.The control model of the system and the control algorithm suitable for the inverter process are analyzed.And then based on the analysis of the control model designed the PID controller and fuzzy controller.The design of fuzzy controller includes the selection of membership function,fuzzy rules and defuzzification.According to the controller designed above,the system is simulated by Simulink,and the results show that the controller design is feasible.And realized the SPWM digital control scheme on the prototype.The results show that the output voltage of the system is of good quality and the system is stable in every case.