基于虚拟磁链定向的NPC三电平逆变器有限控制集模型预测控制
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摘要
针对传统的NPC三电平逆变器有限控制集模型预测控制(FiniteControlSetModelPredictive Control,FCS-MPC)存在计算量大、du/dt高等问题,提出了一种改进的FCS-MPC策略。通过添加开关跳变等约束条件,计算量减至传统FCS-MPC的1/3,同时降低了du/dt;以电压预测代替电流预测,进一步降低了算法的计算量。此外,给出了一种改进的电网虚拟磁链观测模型。根据逆变器αβ坐标系下的离散数学模型估算出电网电压,而后采用一阶低通滤波器计算电网虚拟磁链,减小了虚拟磁链的波动。仿真结果验证了所提出的虚拟磁链观测方法的有效性和NPC三电平逆变器FCS-MPC策略良好的动静态特性。
The traditional finite control set model predictive control(FCS-MPC) for NPC three level inverter has drawbacks of large computational burden and high du/dt. In order to solve those problems, an improved strategy of FCS-MPC is proposed. The computational burden is reduced to 1/3 of origin and the du/dt drops by adding switch jumps and other constraints. The current prediction is replaced by voltage prediction,which further reduces the computational burden. In addition, an improved virtual flux observer model is presented. According to the discrete mathematical model of the inverter under the αβ coordinate, the grid voltage is estimated. And then the first order low-pass filter is used to calculate the virtual flux. As a result,the fluctuation of the virtual flux is reduced. The simulation results show the effectiveness of the proposed virtual flux observer and the good dynamic and static characteristics of the NPC three level inverter FCS-MPC strategy.
The traditional finite control set model predictive control(FCS-MPC) for NPC three level inverter has drawbacks of large computational burden and high du/dt. In order to solve those problems, an improved strategy of FCS-MPC is proposed. The computational burden is reduced to 1/3 of origin and the du/dt drops by adding switch jumps and other constraints. The current prediction is replaced by voltage prediction,which further reduces the computational burden. In addition, an improved virtual flux observer model is presented. According to the discrete mathematical model of the inverter under the αβ coordinate, the grid voltage is estimated. And then the first order low-pass filter is used to calculate the virtual flux. As a result,the fluctuation of the virtual flux is reduced. The simulation results show the effectiveness of the proposed virtual flux observer and the good dynamic and static characteristics of the NPC three level inverter FCS-MPC strategy.
引文
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[10]KOURO S,CORTES P,VARGAS R,et al.Model predictive control-A simple and powerful method to control power converters[J].IEEETransactions on Industrial Electronics,2009,56(6):1826-1838.
[11]CORTES P,RODRIGUEZ J,SILVA C,et al.Delay compensation in model predictive current control of a three-phase inverter[J].IEEETransactions on Industrial Electronics,2012,59(2):1323-1325.
[2]BARROS J D,SILVA J F A,JESUS E G A.Fast-predictive optimal control of NPC multilevel converters[J].IEEE Transactions on Industrial Electronics,2013,60(2):619-627.
[3]XIA C,LIU T,SHI T,et al.A simplified finitecontrol-set model-predictive control for power converters[J].IEEE Transactions on Industrial Informatics,2014,10(2):991-1002.
[4]ZHANG Y,LIN H.Simplified model predictive currentcon trolmethodo fvoltage-source inverter[C].2011 IEEE 8th International Conference on Power Electronics and ECCE Asia,IEEE,2011:1726-1733.
[5]谷鑫,张策,耿强,等.简化三电平整流器模型电流预测控制[J].电工电能新技术,2014,33(2):12-17.GU Xin,ZHANG Ce,GENG Qiang,et al.Simplified model current predictive control of threelevel rectifier[J].Advanced Technology of Electrical Engineering and Energy,2014,33(2):12-17.
[6]赵仁德,贺益康.无电网电压传感器三相PWM整流器虚拟电网磁链定向矢量控制研究[J].中国电机工程学报,2005,25(20):56-61.ZHAO Rende,HE Yikang.Virtual line-flux-linkage oriented vector control of three-phase voltage source PWM rectifier without line voltage sensors[J].Proceedings of the CSEE,2005,25(20):56-61.
[7]LI H,TAN G,FANG J,et al.Study of multilevel rectifier in high power system based on a novel virtual flux observer[C].Power Electronics and Motion Control Conference,IEEE,2009:1618-1621.
[8]张星,瞿文龙,陆海峰.一种能消除直流偏置和稳态误差的电压型磁链观测器[J].电工电能新技术,2006,25(1):39-43.ZHANG Xing,QU Wenlong,LU Haifeng.Method for elimination of DC offset and steady state error for voltage module flux observer[J].Advanced Technology of Electrical Engineering and Energy,2006,25(1):39-43.
[9]张清鹏,万健如.PWM整流器无电压传感器预测电流控制[J].电子测量与仪器学报,2016,30(5):817-823.ZHANG Qingpeng,WAN Jianru.Predictive current control without voltage sensor for PWMrectifier[J].Journal of Electronic Measurement and Instrumentation,2016,30(5):817-823.
[10]KOURO S,CORTES P,VARGAS R,et al.Model predictive control-A simple and powerful method to control power converters[J].IEEETransactions on Industrial Electronics,2009,56(6):1826-1838.
[11]CORTES P,RODRIGUEZ J,SILVA C,et al.Delay compensation in model predictive current control of a three-phase inverter[J].IEEETransactions on Industrial Electronics,2012,59(2):1323-1325.