Research On FCS-MPC Algorithm Optimization Based On T-type Three-level Converte

With the development of distributed generation technology,T-type three-phase three-level converter has been applied more and more widely due to its simple topology,low conduction loss and high economic value.Finite control set model predictive control(FCS-MPC)is increasingly applied in converter systems due to its advantages of fast dynamic response,simple principle,easy implementation,no modulation,and simultaneous processing of multiple objectives and constraints.However,the traditional FCS-MPC has some problems,such as large computational load,cumbersome weight factor design,low control accuracy at low frequency and unfixed switching frequency.In order to solve these problems,a FCS-MPC algorithm optimization study based on T-type three-phase three-level converter system is carried out in this paper.And the specific study work is as follows.1)The basic principle,traditional FCS-MPC strategy and simulation system of T-type three-level converter are analyzed.First,the mathematical models of AC side,DC side and basic voltage vectors of converter are established based on operation mechanism,and the influence of different voltage vectors on neutral-point potential is analyzed.Second,the principle and algorithm implementation method of traditional FCS-MPC in converter system are analyzed.Third,a T-type three-phase three-level converter simulation system is built,and the problems of traditional FCS-MPC algorithm are analyzed according to its simulation results.2)Aiming at the problems of large computational load and cumbersome weight factor design in traditional FCS-MPC algorithm,an optimized FCS-MPC algorithm based on new sector optimization and capacitor charging balance is proposed to reduce algorithm computation load,eliminate weight factor and improve system performance.According to the simulation and experiment results,compared with the traditional FCS-MPC algorithm,the proposed optimization algorithm reduces operation time by 16.1 μs,and makes the system have better steady-state and transient performance without vector traversal and weight factor.3)Aiming at the problems of low control accuracy,unfixed switching frequency and scattered current harmonics in traditional FCS-MPC algorithm,an optimized FCS-MPC algorithm based on zero-sequence component injection and vector synthesis with neutral-point potential deviation suppression is proposed to improve control accuracy,fix switching frequency,reduce current harmonics and improve system performance.According to the simulation and experiment results,compared with the traditional FCS-MPC algorithm,the proposed optimization algorithm reduces current harmonics by3.22%,and makes the system have better steady-state and transient performance with fixed switching frequency of 10 k Hz and without weight factor.4)A T-type three-phase three-level converter experiment platform based on d SPACE is designed and built.First,the design scheme of overall experimental platform structure is analyzed.Second,the design ideas of main components and modules in main circuit and control circuit are analyzed.Finally,the experimental platform is built.