Single-stage Three-phase High-gain Boost Three-port Integrated Inverter

With the increasing shortage of traditional fossil energy,photovoltaic,wind and other renewable energy power generation has attracted more and more attention from governments because of its clean,cheap,non-polluting,and abundant reserves.Therefore,photovoltaic power generation technology has also obtained unprecedented development.The traditional two-port photovoltaic off-grid inverter has no direct energy storage function,and the power supply stability is relatively poor.In order to improve the stability of photovoltaic off-grid inverters,a three-port off-grid inverter with energy storage function is usually required.Therefore,the three-port off-grid inverter has important theoretical value and application prospects.On the basis of discussing the development and current situation of the three-port integrated inverter,this paper proposes a single-stage three-phase high-gain boost type three-port integrated inverter,and its circuit topology,dual-loop improved partitioned SPWM energy management control In-depth theoretical analysis,simulation and experimental research have been carried out on key technologies such as strategy,steady-state principle characteristics,voltage transmission ratio expression,and key circuit parameter design.The single-stage three-phase high-gain Boost three-port integrated inverter circuit topology is composed of an input filter capacitor,an energy storage inductor with a center tap,a three-phase inverter bridge and a three-phase output capacitor filter.And the drain and source of the energy storage switch are respectively connected to the center tap of the energy storage inductor and the negative terminal of the input DC source,between the input DC source,the positive terminal of the battery and the two ends of the energy storage inductor with a center tap Connect a battery charging and discharging switch unit(consisting of a charging branch switch,a discharging branch switch and two blocking diodes),with single-stage power conversion,three power supply modes,high voltage gain,load overload and short-circuit reliability Higher merits.The dual-loop improved partitioned SPWM energy management control strategy with the outer loop of the effective value of the voltage of the photovoltaic cell MPPT and the inner loop of the instantaneous value of the energy storage inductor current is to divide a low-frequency output cycle into six 60° working intervals through a three-phase reference voltage signal,Each section generates a bridge arm PWM signal that meets the working mechanism of the Boost circuit,which realizes the photovoltaic cell MPPT,the stability of the output voltage and the smooth and seamless switching under three different power supply modes.In-depth analysis and study of the steady-state principle characteristics of the single-stage three-phase high-gain Boost three-port integrated inverter,the stability of the control loop,the high-frequency switching process,the voltage transmission ratio of the three power supply modes and other key issues have been obtained.Important conclusions etc.are deduced.Using the proposed circuit topology and energy management control strategy,a 3k W80-110VDC/380V50 Hz AC single-stage three-phase high-gain Boost three-port integrated inverter prototype was successfully designed and developed.The PSIM simulation and experimental results show that the proposed Single-stage three-phase high-gain Boost three-port integrated inverter has excellent performance such as single-stage power conversion,high voltage gain,high conversion efficiency,high output waveform quality,and good power supply stability.Fully confirmed the correctness and advancement of the resulting circuit topology and energy management control strategy.