Three-phase High-voltage Boost Current Three-port Photovoltaic Independent Power Supply Syste

With the increasing consumption of non renewable energy such as oil,coal and natural gas and serious damage to the environment and ecology,energy and environment have become major problems faced by mankind in the 21 st century.New energy sources such as solar energy,wind energy and hydrogen energy have the advantages of clean and pollution-free,wide distribution and rich reserves.Their development and utilization have attracted more and more attention all over the world.In order to actively deal with the ecological deterioration and greenhouse effect caused by carbon emissions,China has vigorously developed clean and lowcarbon new energy,in which photovoltaic power generation accounts for the main part.Compared with voltage source photovoltaic inverter,current source photovoltaic inverter has attracted extensive attention because of its advantages of single-stage boost,suitable for photovoltaic cell output characteristics and long service life.In order to ensure the stability of three-phase photovoltaic power supply system with high voltage gain,the research of this thesis is of great theoretical value to ensure the stability of three-phase photovoltaic power supply system.On the basis of discussing the development and research status of photovoltaic independent power supply system,this thesis proposes a three-phase large boost current source three port photovoltaic independent power supply system,makes in-depth theoretical analysis,simulation and experimental research on its circuit topology,energy management control strategy,stability principle characteristics,main circuit parameters and other key technologies,and obtains important conclusions.The proposed circuit topology of three-phase large boost current source three port photovoltaic independent power supply system is composed of input filter capacitor,coupling inductance with center tap,three-phase inverter bridge with blocking diode and three-phase output filter capacitor cascaded in sequence,and a battery charge discharge switching unit is connected between the left and right sides of the coupling inductance with center tap and the positive terminal of the battery.The three-phase large boost current source three port photovoltaic independent power supply system has three working modes: dual input,dual output and single input and single output.The dual loop zoning improved SPWM energy management control strategy with photovoltaic MPPT output voltage outer loop and central tap coupled inductive current inner loop is adopted to realize the MPPT of photovoltaic cell,the stability of three-phase output voltage and the three working modes of the system.In a high-frequency switching cycle,the dual input working mode of the system is composed of six sections including two energy storage sections and four energy release sections.The dual output working mode is composed of six sections including four energy storage sections and two energy release sections.The single input single output working mode is composed of four sections including two energy storage sections and two energy release sections.The additional active clamp circuit effectively suppresses the off voltage spike of the energy storage switch caused by the leakage inductance of the center tap coupling inductor.The design criteria of the main circuit parameters such as the center tap coupling inductor,the input / output filter capacitor,the battery charge discharge switching unit and the voltage and current stress of the three-phase inverter bridge power device are derived.Using the proposed circuit topology and energy management control strategy,an experimental device of 3k VA 80-110 VDC /132VDC/ 220V50 Hz AC three-phase large boost current source three port photovoltaic independent power supply system is designed and developed.PSIM steady-state and dynamic simulation and experimental results show that the three port independent power supply system has the advantages of large boost ratio,three working modes,wide input voltage range,small output voltage THD,continuous and stable output power supply,and provides an effective scheme for photovoltaic independent power supply system with low input voltage or wide input voltage.