Large Boost Ratio Quasi-Z Source Three-port Three-phase Integrated Power Generation System

Inverter is an important part of solar photovoltaic power generation system.Compared with PWM inverter,the quasi-Z-source inverter has been widely used because of its advantages such as single-stage up-down voltage conversion,bridge arm allowing through or open circuit,power switch without dead zone or overlap time,and high output waveform quality.However,there is a restrictive relationship between the boost factor and the modulation ratio of the quasi-Z-source inverter,and there are some defects such as weak boost ability,large power switching voltage stress and poor output waveform quality.In addition,the photovoltaic independent power supply system is affected by the external environment such as illumination,which cannot guarantee the continuity and stability of power supply.Therefore,while improving the pressure-boosting capacity of quasi-Z source,reducing its volume and weight and improving the stability of photovoltaic power supply are the key problems to be solved at present.On the basis of discussing the development and present situation of traditional quasiZ-source inverter and three-port PWM inverter,this paper proposes a quasi-Z-source threeport three-phase integrated power generation system with large voltage boost ratio.The key technologies such as circuit topology,photovoltaic and battery master-slave power distribution energy management and improved SVPWM control strategy,steady-state principle characteristics,voltage transmission ratio expression,high voltage boost ratio magnetic integrated impedance network.Big step-up ratio proposed quasi three port Z source three-phase circuit topology integrated power generation system,is by the input filter capacitor,big step-up ratio magnetic integration impedance network,compound active clamp circuit,three-phase inverter and LC filter circuit of three-phase bridge cascade in sequence,and in the end of the big step-up ratio magnetic integration impedance network energy storage capacitor and battery charge and discharge circuit switch.Among them,the high voltage boost ratio magnetic integrated impedance network is composed of three coupling inductors,four energy storage capacitors and two diodes integrated on a UIU magnetic core,and the compound active clamp circuit is composed of a resonant inductor,a clamp capacitor and an auxiliary switch.Has proposed pv MPPT dc input voltage,output voltage feedback control of pv and battery energy management improved SVPWM control of master-slave power allocation strategy,achieve three different power supply mode of smooth transition and output voltage stability.The steady-state principle characteristics of quasi-Z source three-port three-phase integrated power generation system with large voltage boost ratio are studied in depth,including the analysis of high-frequency switching process of additional compound active clamp circuit,the analysis of AC and DC magnetic flux of magnetic integrated inductors,and the magnetic integrated impedance network model with large voltage boost ratio.The design criteria of key circuit parameters,such as voltage transmission ratio expression,magnetic integrated impedance network,input filter capacitor,compound active clamp circuit.Based on the proposed circuit topology and energy management control strategy,an experimental prototype of 1k VA 80-110VDC/220V50 HZAC high-voltage boost ratio quasi-Z source three-port three-phase integrated power generation system is designed and developed.The PSIM simulation and experimental results show that,The proposed integrated power generation system has the advantages of single-stage power conversion,strong voltage boost ability,small volume and weight,zero voltage switching by inverter bridge and compound active clamp circuit,high reliability of power supply and good quality of output waveform.