The Research On Nonlinear Control Strategy Of The Three-phase Voltage Type PWM Converter

With the development of clean energy,more and more transformation devices are applied to modern industry.In recent years,various control techniques based on PWM converter widely introduced into the power transformation equipment,truly realizing the alternative clean energy,efficiency and environmental protection because of its net side current realization of sine wave,the power factor of approximate to 1,the advantages of energy bi-directional flow.In this paper,the working principle of PWM converter is introduced,and the mathematic model of different coordinate system is deduced in detail.Secondly,the sliding mode variable structure control of a three-phase voltage type PWM converter is proposed.Making full use of the sliding mode variable structure control in the error is small to the characteristics of fast track and PI control under the condition of the inner ring current error performance good convergence,this paper provides a PI control and sliding mode variable structure control with the combination of control strategy.Namely,when the inner ring current error is small,the sliding mode variable structure control is adopted;when the inner ring current error is large,PI control is adopted.The expressions of the sliding mode and detailed analysis of the sliding mode variable structure mechanism are derived in detail.This paper gives the stability of the system parameter design analysis and the boundary values of the test in the MATLAB/Simulink which is built by all decoupling dual closed loop simulation model of second order analysis of the double closed loop control system response time and anti-jamming performance,verifying the correctness of the proposed control strategy.In addition,the model predictive power control of three-phase voltage type PWM converter is also studied.Target function and constraint functionare derived in detail,making each cycle power minimum error.This article provides a control flow chart of model predictive control by selecting the appropriate voltage vector and calculating the corresponding voltage vector function of time,deriving from SVPWM modulation technology.Simulation models of the MPC are analyzed under different operating scenarios of Fourier(FFT),network flow load function change active adjustment ability and network flow side voltage when load mutation load disturbance resistance in MATLAB/Simulink,verify the effectiveness of the proposed control strategy.Finally,the working principle of TMS320F2812 hardware system and program flow chart of software design are introduced in detail.