Research On Low Voltage Distribution Network Inverter Using RB-IGBT

The micro smart grid integrates renewable energy generation technologies,energy management systems,and transmission and distribution infrastructure to increase energy efficiency,improve power supply safety and reliability,reduce power loss in the grid and environmental impact.The micro smart grid is conducive to expanding the large-scale access of distributed power and renewable energy,providing reliable supply to the load area,and realizing an effective active distribution network.The distribution network inverter is a key component of the micro smart grid.Different inverter circuit topologies and various inverter control schemes determine the power quality of the distribution terminal.The thesis firstly investigates the development of low-voltage DC power distribution technology in smart grid,the topology structures and working characteristics of low-voltage DC distribution network inverter,and studies the control characteristics and operating conditions of low-voltage distribution network inverters.The two-level and multi-level inverter structures for low-voltage power distribution are mainly analyzed.In this thesis,the T-type three-level circuit topology in multi-level inverter is studied.The working principle and control method of T-type three-level inverter composed of common IGBT and RB-IGBT are compared and analyzed.The SPWM modulation strategy of this inverter topology is also studied in detail.Under the condition of setting target parameters:DC input 1000V and rated power 200kW,the parameter design of T-type three-level inverter based on RB-IGBT is carried out.At the same time,double closed-loop control and improved PWM modulation algorithm are studied.This thesis then studies the relationship between switching frequency,efficiency,and output power of a T-type three-level inverter composed of RB-IGBTs,analyzes and calculates the system loss of T-type three-level inverter circuit based on RB-IGBT,and analyzes and compares the losses of T-type three-level inverter circuit and two-level circuit based on traditional IGBT.Finally,the working conditions suitable for a T-type three-level inverter based on RB-IGBT are given.The thesis models and simulates the T-type three-level inverter distribution network system based on RB-IGBT,and completes the simulation analysis of open-loop and closed-loop conditions.Also,a Matlab-based inverter loss calculation and analysis software is designed and developed.The software adopts a graphical interface,witheasy and clear fill-in parameter design,which can calculate and compare the losses of the distribution network inverter systems with different IGBTs and different circuit topologies.At the end of the thesis,a T-type three-level inverter circuit experimental platform based on RB-IGBT is built.The correctness of the previous theory and simulation analysis is verified by the experiment.