Research On SVM-DTC AC Variable Frequency Speed Regulation With Dead-time Compensation

With the rapid development of AC variable technology, its control strategy alsohas been put forward higher requirements. Traditional direct torque control andvector control technology has certain shortcomings, and the presence of dead timein the AC speed control algorithm can cause the problem of dead-time effect. Tosolve the above problems, this topic has proposed a SVM-DTC AC variablefrequency speed regulation with the strategy of dead-time compensation to meet theexperimental teaching of universities.Firstly, the mathematical model of induction motor has been established, thebasic principle of the coordinate transformation has been studied, and themathematical model has been converted into mathematical models of differentcoordinate. The control strategy of SVM-DTC has been proposed, the principle ofspace vector modulation algorithm has been analyzed, and three-phase voltagereconstruction process has been completed.Secondly, the problem of the dead-time effect after the introduction of deadtime in the system algorithms has been analyzed, the reason and influencing factorsof zero current clamp phenomenon has been analyzed. For the problem of dead-timeeffect, the calculation of equivalent dead time influenced by a variety of factors hasbeen completed. The new filters and current polarity detection circuit has beendesigned to realize the judgment of current polarity and the division of the currentsector, and the judgment of current phase which needs to be compensated has beencompleted to realize the dead-time compensation strategy based on the currentvector.Thirdly, the hardware circuit of AC speed experimental platform has beendesigned, completed the design of rectifying circuit, inverter circuit and otherauxiliary circuits. The inverter circuit has used intelligent power module to replacethe traditional discrete components, to simplify the circuit structure. The motioncontrol circuit which is based on DSP2812has been used, and it communicates withthe host computer by PCI bus.Finally, the simulation model of the system has been simulated by usingMatlab/Simulink, the feasibility of the system principles has been verified, andachieved good operating performance. The interactive interface has been designedby using Visual C++programming, to realize safe and reliable control, has goodopenness and interoperability. The entire system has been investigatedexperimentally on AC speed experimental platform.Experimental results show that: the AC experimental platform which is based on the SVM-DTC control algorithm has overcome the shortcomings of traditionalcontrol algorithm, and the good operating performance has been verified in theexperiment. After the introduction of the dead-time compensation based on currentvector, the problem of dead-time effect caused by dead time has been eliminated,and the operating performance of the system has been well improved. In this paperthe proposed SVM-DTC algorithm with dead-time compensation based on AC speedexperimental platform has achieved good static and dynamic performance.