Three-dimensional Space Vector Modulation Strategy Of Three-phase Four-leg Inverter

As industrial drives, rail transport sector with the rapid development of modern power electronics technology, the performance requirement of the inverter system is increas ing day by day. A three-phase four-leg inverter because of its compact structure, small weight and has a good unbalanced load capacity received a lot of attention. In this paper, a deep research on the three-phase four-leg inverter which is based on 3D-SVPWM strategy is carried out.Firstly, an overview of the development trend of inverter technology, comparative analysis of the topology of several three-phase four-wire inverter. Based on the phase sequence symmetrical component decomposition method and coordinate transformation theory, the mathematical model of three-phase four-leg inverter were derived, analyzes the reasons for the three-phase voltage imbalance and proposes three control strategies, focusing on Principle of voltage and current double closed loop PI control strategy.Then, summarized several three-phase four-leg inverter modulation strategy, focusing on a-b-c coordinate system based on the following 3DSVPWM strategy. Built a three-phase four-leg inverter simulation model in Matlab/Simulink simulation software, us ing the opened-loop and closed-loop simulation to verify the accuracy and validity of the algorithm model control algorithm.Finally, control TMS320C6713 DSP chip control procedures, based on the real-time RT-Lab emulator built three-phase four-leg inverter semi-physical simulation platform. Respectively, with the balance of the three-phase load, three-phase and three-phase unbalanced load with mixed conditions with linear load the system test, the test results prove the correctness of the control system design and control the effectiveness of the policy.