Three-level Inverter Space Voltage Vector Pwm Modulation Realization

In recent years, multilevel technology has become an effective and practical solution f or high-voltage high-power application field. As described in many literatures, using multilevel technology, the voltage stress on switches will be reduced, the shape of out put waveform will be improved and the rate of voltage and power can be increased too. Diode-clamped three-level inverter is the most widely used and investigated topology at present. As the basis of further researches, the paper mainly focuses on the control system of diode-clamped three-level inverter.The topology structure and mathematical model of the diode-clamped three-level inverter is researched in this thesis firstly. On the base of it, the three-level SVPWM (space vector pulse width modulation) algorithm is deduced in detail and is improved partly, so the control algorithm is simplified. In order to solve the problem of neutral point balance, the operating time of positive and negative space voltage vectors is timely redistributed. The results of theoretical study and simulation prove that SVPWM algorithm and control of neutral point balance is true and effective.This paper also introduces the design of three-level inverter, which includes the main Circuit, Switch Device Driver Circuit, Current and Voltage Detecting Circuit and Protect Circuit. Consider that main circuit of three-level inverter have many switches and the driving signal can't be connected to the same ground, this paper designs an opt coupler isolation driving protection circuit, which can reduce the electromagnetic interference and protect the power device real-time when abnormity phenomenon such as excessive currents appears. Lastly, this paper implements the SVPWM control strategy of three-level inverter base on TMS320LF2407 DSP digital control platform.