Research On Control Strategy For Matrix Converter

MC (Matrix Converter) as one type of general power converter, can realize n phase to m phase voltage conversion and provide sinusoidal output voltages with varying amplitude and frequency, while drawing sinusoidal input currents with unity power factor. This converter can render bi-directional power flow and need no energy storage components except small AC filters for elimination of switching ripples. The MC function is different by changing the control algorithm as rectifier, inverter, converter, etc. The main content of this thesis are shown as followsThe equivalent AC-DC-AC topology of MC is researched, and an improved dual space vector PWM strategy is proposed. The vector amplitude fluctuation, switching losses and harmonics elimination problem are solved. The maximum voltage gain of MC at higher frequency is only 0.866, which is restricted by input phase current quality and should be compromised according to the load demand. Logic process of Four-Step Half Soft Commutation will be studied based on DSP hardware. Moreover, inverse effects of harmonic and etc. problems, witch induced by scheme design and switching work, are analyzed.The mathematical models of DFIG at d-q and m-t coordinate systems and its stator flux-oriented vector control strategy are investigated. The dual closed loop PI scheme of decoupling control active and passive powers of DFIG is established. Main circuit topology configuration of dual DSP and CPLD control platform and control system software, hardware design steps are designed based on matrix converter excited. The reasons of selecting main devices parameters and the ideas of designing drive and protection circuit are proposed. The main function and its control diagrams are illustrated.The online calculation method of switching angle of IGBT is studied. A model of MC can be obtained based on Mechanized Mathematics Method, in term of eliminating selected harmonics. The online simulation calculation of switching angle of IGBT is realized. Combining Mechanized Mathematics Method, Electrical Power and Electronics and Cybernetics, well-knit base of theory is given in order to applying MC in VSCF wind generator. The less store space of EPROM of DSP and the flexibility of excited system of wind generator based on MC are validated by simulation results in this thesis.