Multi-objective cooperative control of a junction-temperature-orientated three-level traction converter

The Insulated-Gate Bipolar Transistor (IGBT) module is the core of the three-level (3L) traction converter. In order to improve the lifetime of the traction converter, a model predictive torque control (MPTC) based on the junction temperature constraint is proposed. Firstly, the optimization range is reduced by judging the sector where the reference voltage vector locates, as the traditional MPTC needs to be optimized 27 times in each sampling period, which requires a large amount of calculation. Secondly, by simplifying the calculation of IGBT power loss and dynamically constraining it in the cost function, the performance of optimal voltage vector balancing control can be balanced with power loss. Simulation results show that the proposed method reduces the junction temperature of the power semiconductor and prolongs the converter lifetime compared with the traditional strategy.