【作者】 王超；

【导师】 阎彦；

【作者基本信息】 天津大学 ， 电气工程， 2018， 硕士

【摘要】 矩阵变换器(Matrix Converter,MC)作为AC-AC变换器,具有功率密度高、输入输出波形正弦、无中间直流储能环节以及能量双向流动等优点。近年来,针对MC已提出了多种调制/控制方法,其中,将矩阵变换器与有限集模型预测控制(MPC)相结合,既符合MC多目标电能变换需求,也使MC具备更好的动态性能。然而,受MC结构特性带来的限制,MC-MPC仍存在一些不足。MC共有27种开关状态,这些开关状态对应的电压矢量(零矢量除外)幅值或相角随时间而变化。这一状况下,MC-MPC在单位采样周期内完成27种开关状态的穷举寻优,需要消耗大量计算时间。适当降低采样频率可以缓解MC-MPC在线计算量大的问题,但会引起模型预测精度变差、MC输出侧电流和电源侧电流谐波增大。此外,受MC输入端电压谐波以及输入侧滤波器谐振影响,MPC下的MC输出电流和输入电流波形中也会存在谐波。对此,针对上述问题,本文引入开关状态切换点自由度,依据最优开关状态在最佳时刻切换的思想,提出矩阵变换器开关切换点优化预测电流控制策略。本文首先分析矩阵变换器传统模型预测电流控制策略,得到矩阵变换器连接阻感以及永磁同步电机负载下系统各组成部分的数学建模,并对该数学模型进行离散化,建立开关切换点优化策略下的输出电流预测模型和电源侧瞬时无功功率预测模型;其次根据误差最小化原则,利用最小二乘法研究不同开关状态对应的最优开关切换时刻的计算方法;最后以电源侧瞬时无功功率和输出电流的跟踪评价以及终端评价为控制目标构造价值函数,来完成最优开关状态以及对应开关切换时刻的寻优。利用Matlab/Simulink搭建了矩阵变换器传统模型预测电流控制策略和开关切换点优化预测电流控制策略仿真模型,在相同的仿真条件下对传统策略和开关切换点优化策略做了对比仿真研究,确认了开关切换点优化策略的有效性。最后通过矩阵变换器实验系统对本文提出的开关切换点优化策略进行了实验验证,实验结果证明了本文提出的开关切换点优化策略的可行性与有效性。更多还原

【Abstract】 As an AC-AC converter,Matrix Converter(MC)has the advantages of high power density,sinusoidal input and output waveforms,no intermediate DC energy storage,and energy bidirectional flow.In recent years,a variety of modulation/control methods have been proposed for MC.The combination of matrix converter and finite set model predictive control(MPC)not only meets the requirements of MC multi-target power conversion,but also makes MC have better dynamics.performance.However,due to the limitations imposed by the structural characteristics of MC,MC-MPC still has some shortcomings.The MC has a total of 27 switching states,and the voltage vector(except the zero vector)amplitude or phase angle corresponding to these switching states changes with time.Under this circumstance,the MC-MPC performs exhaustive optimization of 27 switching states in a unit sampling period,which requires a large amount of computation time.Properly reducing the sampling frequency can alleviate the problem of large MC-MPC online calculation,but it will cause the model prediction accuracy to deteriorate,and the MC output side current and power supply side current harmonics to increase.In addition,due to the voltage harmonics at the MC input and the input side filter resonance,harmonics are also present in the MC output current and input current waveforms under MPC.In view of the above problems,this paper introduces the degree of freedom of switching state switching point,according to the idea that the optimal switching state is switched at the optimal time,the optimal switching current control strategy of the switching point of the matrix converter is proposed.In this paper,the traditional model predictive current control strategy of matrix converter is firstly analyzed,and the matrix converter connection resistance and the mathematical modeling of each component of the system under the load of permanent magnet synchronous motor are obtained.The mathematical model is discretized and the switching point optimization is established.The output current prediction model and the power-side instantaneous reactive power prediction model under the strategy;secondly,according to the principle of error minimization,the least square method is used to study the calculation method of the optimal switching time corresponding to different switching states;The tracking evaluation of the power and output current and the terminal evaluation are the control target construction value functions to complete the optimization of the optimal switching state and the corresponding switching timing.The traditional model predictive current control strategy of matrix converter and the simulation model of switching switch point optimization predictive current control strategy are built by Matlab/Simulink.The simulation analysis of traditional strategy and switching point optimization strategy is carried out under the same simulation conditions.The effectiveness of the switching point optimization strategy.Finally,the experimental results of the switching point optimization strategy proposed in this paper are verified by the matrix converter experimental system.The experimental results demonstrate the feasibility and effectiveness of the proposed switching point optimization strategy.更多还原