The Research Of Series Connected Diode Clamping IGBT Equalizing

With the developing of power electronics technology, the Isolated Gate Bipolar Transistor(IGBT) is widely used in different area. However, IGBT can’t accommodate some engineering requirement in somehigh voltage cases for the lower withstand voltage of a single device. The serial use of IGBT provides a useful method to improve the voltage level, and it is a very important way to achieve high-voltage power electronic converters.The difference of self parameters and peripheral circuits between different IGBTs and the short switching process of IGBTs makes the unbalance of collector-emitter voltages between different IGBTs a key issue that must be addressed.Firstly, this paper analyzes the structure and the operation characteristics of IGBT, and studies the the factors that causes uneven voltage pressure between series connected-IGBTs.Analysis the relationship between the difference of self parameters and driving signal and the voltage imbalance.Then, a new type of self equalizing series connected IGBT circuitby diode clamping is proposed based on the study of series connected IGBT circuit with diode and capacitor, and the various stages between the circuit operations are analyzed. An auxiliary circuit for energy feedback is designed.After that, the equalizing ability of this circuit in pulse delay of driving signal is studied and the method to design the component parameters is proposed.Subsequently, asingle-phase inverter based on equalizing series connected IGBT is designed, and the various stages between the circuit operations are analyzed. Athree-phase inverter based on this circuit topology is designedon the basis of this topology, and Space Vector Pulse Width Modulation(SVPWM) method is used to control it.Finally,the experiment platform of three-phase inverter based on equalizing series connected IGBT is built according to theoretical research and analysis. The experiment result proves that this circuit can inhibition the voltage imbalance of each IGBT and can limit the voltage of IGBTeffectively. The result proves the effectiveness of this voltage balancing method.