Research On Five-Level Medium-Voltage Inverter

It is important to study and develop medium-voltage drive (MVD) for energyconversion and electrical drive. The controller is one of the most important partsof MVD. This paper present a novel multi-processor controller, based on the principle of series H-bridge multi-level inverter and phase-shift SPWM, in which single chip microprocessor (SCM), digital signal processing (DSP). And field programmable gate array (FPGA) is firstlyapplied in the design of pulse generator. This controller has following advantages: high speed, high accuracy, high stability, and universal application in terms ofmodularization. The control arithmetic of phase-shift PWM and sub-optimal PWM is achieved.Several topologies of medium-voltage inverters are analyzed and compared inthis paper. Mathematical model for the isolated series H-Bridge inverter isconstructed and the expression of the inverter's output voltage is given. A circuitwith two united series H-bridge cells is simulated by MATLAB, based on the phase-shift SPWM control and sub-optimal PWM control.The results are presented and analyzed in the paper. The controller developed in this paper is very useful for the development of MVD based on series H-bridge.