Research Of Control Strategy Of Indirect Matrix Converter Fed Dual-Three Pmsm Drives

The aim of the thesis is to study high-reliability and high-power density AC to AC drive system for the application of medium voltage large power traction system.Depending on the existing worldwide research fruits,this thesis studied and demonstrated the modulation strategy,suppression of LC resonance in grid currents and model predictive control of indirct matrix converter(IMC)fed dual three-phase PMSM drive in details.Through comparing the benefits and drawbacks of different kinds of IMCs,the 18-switch IMC is chosen as the research object.After comparing the merit and demerit of different bidirectional switches,the bidirectional switch based on common emitter series IGBT solution is designed for the IMC in this thesis.The modulation strategy with zero vector,coordination control and commutation strategy are presented after introduction of non-zero vector modulation strategy.The virtual average dc link voltage is constant under zero vector modulation,it is suitable for closed-loop control on motor side and it do not need to modify modulation ratio of inverter stage.So the zero vector modulation strategy is confirmed as the basis of modulation strategy of other parts of this thesis.Considering strong coupling,high order and nonlinearity of dual three phase PMSM drive,the thesis introduced the mathematical models of dual dq transformation and vector space decomposion.The vector control strategies are introduced based on the such two models for the IMC fed dual three-phase PMSM.The modulation strategy is designed on inverter stage based on the maximum adjacent four voltage vectors,which is in favour of rasing voltage radio and easy to realization.This thesis designed the active damping control strategy to suppress LC resonance based on interleaved control and power balance for IMC.According to LC resonance frequency,the phase shifting angel is designed to force vector overlapping,and it can reduce the peak value and distortion of grid currents.By designing appropriate high-passing filter,the proposed active damping strategy extracts high frequency voltage components and injects to the reference of input grid currents.Furthermore,the thesis also tried to propose the model predictive control for the IMC fed dual three-phase PMSM drive based on dynamical modeling of switch,filter and load.The load currents,torque,flux and reactive power on grid side are setted as the control goals.By constructing the cost functions to predict performance and of each switching states,the control goal is realized.Finally,both simulation and experiment results are given to verify the theoretical analysis and control strategy in this thesis.