Experimental Study Of Two-stage Matrix Converter Based On Optimization Commutation Strategy

As a potential "green inverter", two-stage matrix converter has the followingadvantages, bi-directional power flow, function with four-quadrant operation,adjustable input power factor, input and output current waveform is a sine wave,adjustable output voltage and frequency range is wide,no DC-link,commutationstrategy is simple and reliable. In this paper, the research status, the strategy of doublespace vector modulation and zero current commutation principle of two-stage matrixconverter is analyzed. At last, the simulation model is built and an experimentalprototype is established.Firstly, the research status about commutation strategy,topologies, modulationstrategy of two-stage matrix converter is analyzed. And the principle of double spacevector strategy of two stage matrix converter is studied, and a simulation study ismade. In this paper, a optimized zero commutation principle is proposed, based on thezero current commutation principle, in order to ensure fuller zero currentcommutation time, the rectifier level zero vector is re-assigned in the inverter circuit.At present, the strategy of space vector modulation which based on non-zerovector of the rectifier-level is commonly used for experiment research in the domestic,in this paper, the strategy of double space vector modulation which based on zerovector of the rectifier-level is researched for experimental prototype. Theexperimental prototype design includes hardware system and control system. Thedesign principle of the main circuit, the input filter circuit, the clamp circuit,theabsorption circuit and the driving circuit in the hardware system design is analyzedand the design parameters is given; Control system is designed on the basis of thecombination of CPLD and DSP, based on the powerful software functions of DSP,the strategy of double space vector modulation and voltage signals sampling could becompleted quickly, because of owing powerful logic operations and parallelprocessing capabilities, CPLD could quickly achieve the signal output of PWM driveand function of system fault protection. Finally, the experimental results from theexperimental prototype verify the modulation strategy and commutation principle oftwo-stage matrix converter.