Study On Key Techniques Of Matrix Converter & Motor Drive Control System

For a long time, people devoted themselves to searching a new power drive control system, whose power factor can be controlled, with bidirectional power transmission, sinusoid input current waveform, and have a good performance on both dynamic and static state. The emergence of matrix converter motor drive control system has been considered as a perfect option. For its advanced topologic and excellent performance, matrix converter has becoming one of the most interest problems for study. Several key techniques of three phases AC/AC matrix converter and matrix converter feed motor drive system was studied in the paper, including:At the beginning of this paper, it have researched the space vector modulation method of the virtual AC-DC-AC structure by the basic of virtual DC link conception of matrix converter and given the substantive difference and connection between the matrix converter and the dual PWM converter.This paper analyzed and studied the circuit system design of matrix converter. Given the computation and selection method of main loop, with known condition, switch device rated voltage and rated current. Educed the switch frequency harmonic time domain equation of input current and output voltage of matrix converter, from traditional modulation theory, which provide reliable theory argument for attenuation characteristic confirmation and design of input filter circuit. Discussed the cost problem of different input filter circuit; analyzed the truth of produce of over current/over voltage by matrix converter motor drive system in the circumstance of malfunction and disorderly shutdown. Given an original analysis method of protective circuit and computing method of its parameter.Inherence maximal voltage transfer ratio of matrix converter was explained in physical accurately and legibly for the first time, studied maximal voltage transfer ratio under dual space vector modulation, a new method using nonlinear modulation was proposed to develop voltage transfer ratio, discussed the restrict factor and applicability, also verified though simulation.The paper proposed a concept of motor drive control system based on matrix converter topologic, researched the model construction of matrix converter motor drive system. Matrix converter and induction motor were treated as a whole system, dynamic model of matrix converter motor drive system in static two phases (α/β) reference frame was established based on virtual DC link conception. Set up the simulation model of matrix converter motor drive system based on space vector modulation under Matlab/Simulink, the correctness and advantages were verified through simulation. The model has the characters of simple structure, legible concept, using conveniently, and can be used for analysis and CAD of matrix converter motor drive system.The paper systemically studied space vector modulation strategy of matrix converter. Generally clarified the traditional space vector modulation theory based on the analysis of different space vectors of switch combination of matrix converter. Deducted modulation function of each space vector in double-sided modulation; proposed an modified space vector modulation method aimed at reducing switch power lose. Discussed double-sided vector sequence of different modulation strategy, analyzed zero vectors order in distributed zero vectors modulation strategy, clarified the essential influence of different modulation method and zero vectors order on switch power lose and input/output waveform, and provided reasonable basis for selecting modulation method rationally; given a comparison method converter aimed at switch power lose, output voltage waveform quality, input current waveform quality. Indirectly reflected harmonic magnitude in input/output waveform by computing of flux increment introduced by output voltage harmonic, charge increment introduced by input current harmonic:; educed normalized switch lose function, and computing method of normalized harmonic flux and harmonic charge. The correctness and availability were verified through emulation in platform of MATLAB/Simulink.The paper studied direct torque control (DTC) of matrix converter motor drive system at last. Proposed a control method for induction motor, which can control both stator flux and rotor flux, and adjust input power factor at the same time. Established voltage vector table for this control system; Further more analyzed influence of electromagnet torque in DTC by voltage space vector, find out limiting conditions in selecting voltage vectors when flux magnitude and flux angle have antinomy influence in electromagnet torque, hereby proposed an original 12 flux sector optimizing control method. Verified the correctness and validity through the method of simulation; provided implementation of DTC in matrix converter motor drive system, and established the simulation model. The simulation result s indicated that DTC of matrix converter motor drive system have characters of good performance in dynamic response and input power factor close to 1.