Research on Mixed Logic Dynamic Modeling and Finite Control Set Model Predictive Control of Multi-Inverter Parallel System

Parallel connection of multiple inverters is an important means to solve the expansion,reserve and protection of distributed power generation,such as photovoltaics.In view of the shortcomings of traditional droop control methods such as weak anti-interference ability,low tracking accuracy of inverter output voltage and serious circulation phenomenon,a finite control set model predictive control(FCS-MPC)strategy of microgrid multiinverter parallel system based on Mixed Logical Dynamical(MLD)modeling is proposed.Firstly,the MLD modeling method is introduced logical variables,combining discrete events and continuous events to form an overall differential equation,which makes the modeling more accurate.Then a predictive controller is designed based on the model,and constraints are added to the objective function,which can not only solve the real-time changes of the control system by online optimization,but also effectively obtain a higher tracking accuracy of the inverter output voltage and lower total harmonic distortion rate(Total Harmonics Distortion,THD);and suppress the circulating current between the inverters,to obtain a good dynamic response.Finally,the simulation is carried out onMATLAB/Simulink to verify the correctness of the model and the rationality of the proposed strategy.This paper aims to provide guidance for the design and optimal control of multi-inverter parallel systems.

Research on AC Electronic Load with Energy Recovery Based on Finite Control Set Model Predictive Control

Nowadays,AC electronic loads with energy recovery are widely used in the testing of uninterruptible power supplies and power supply equipment.To tackle the problems of control difficulty,strategy complexity,and poor dynamic performance of AC electronic load with energy recovery of the conventional control strategy,a control strategy of AC electronic load with energy recovery based on Finite Control Set Model Predictive Control(FCSMPC)is developed.To further reduce the computation burden of the FCS-MPC,a simplified FCS-MPC with transforming the predicted variables and using sector to select expected state is proposed.Through simplified model and equivalent approximation analysis,the transfer function of the system is obtained,and the stability and robustness of the system are analyzed.The performance of the simplified FCS-MPC is compared with space vector control(SVPWM)and conventional FCS-MPC.The results show that the FCS-MPC method performs better dynamic response and this advantage is more obvious when simulating high power loads.The simplified FCS-MPC shows similar control performance to conventional FCS-MPC at less computation burden.The control performance of the system also shows better simulation results.

Finite-Control-Set Model Predictive Control of Permanent Magnet Synchronous Motor Drive Systems——An Overview

Permanent magnet synchronous motors(PMSMs)have been widely employed in the industry. Finite-control-set model predictive control(FCS-MPC), as an advanced control scheme, has been developed and applied to improve the performance and efficiency of the holistic PMSM drive systems. Based on the three elements of model predictive control, this paper provides an overview of the superiority of the FCS-MPC control scheme and its shortcomings in current applications. The problems of parameter mismatch, computational burden, and unfixed switching frequency are summarized. Moreover, other performance improvement schemes, such as the multi-vector application strategy, delay compensation scheme, and weight factor adjustment, are reviewed. Finally, future trends in this field is discussed, and several promising research topics are highlighted.

Finite Control Set Model Predictive Current Control of a Five-Phase PMSM with Virtual Voltage Vectors and Adaptive Control Set

This paper presents an improved finite control set model predictive current control(FCS-MPCC)of a five-phase permanent magnet synchronous motor(PMSM).First,to avoid including all the 32 voltage vectors provided by a two-level five-phase inverter into the control set,virtual voltage vectors are adopted.As the third current harmonics can be much reduced by virtual voltage vectors automatically,the harmonic items in the cost function of conventional FCS-MPCC are not considered.Furthermore,an adaptive control set is proposed based on voltage prediction.Best control set with proper voltage vector amplitude corresponding to different rotor speed can be achieved by this method.Consequently,current ripples can be largely reduced and the system performs much better.At last,simulations are established to verify the steady and transient performance of the proposed FCS-MPCC,and experiments based on a 2 kW five-phase motor are carried out.The results have validated the performance improvement of the proposed control strategy.

Model Predictive Control-Based Direct Torque Control for Matrix Converter-Fed Induction Motor with Reduced Torque Ripple

To reduce the torque ripple in motors resulting from the use of conventional direct torque control(DTC),a model predictive control(MPC)-based DTC strategy for a direct matrix converter-fed induction motor is proposed in this paper.Two new look-up tables are proposed,these are derived on the basis of the control of the electromagnetic torque and stator flux using all the feasible voltage vectors and their associated switching states.Finite control set model predictive control(FCS-MPC)has then been adopted to select the optimal switching state that minimizes the cost function related to the electromagnetic torque.Finally,the experimental results are shown to verify the reduced torque ripple performance of the proposed MPC-based DTC method.

基于FCS-MPC的分布式HESS功率协调控制

针对孤岛直流微电网中分布式混合储能系统(HESS)协调运行问题,提出一种基于有限控制集模型预测控制(FCSMPC)的功率协调控制策略。该策略采用小波包变换来分解分布式HESS的功率需求,由于分解后信号的特点和分布式HESS中蓄电池初始状态的不同,于是对分解后最低频信号基于蓄电池荷电状态(SOC)设计自适应因数来进一步再分解。由于DC/DC变换器开关状态组合数量较少,使得多步FCS-MPC的滚动优化计算量较少,于是采用FCS-MPC取代双闭环PI控制,提高系统动态响应。搭建含有分布式HESS的孤岛直流微电网模型,并做了3种方案的仿真对比,验证该策略有效平缓了直流母线波动并实现蓄电池SOC一致。该策略有利于提高电网运行的稳定性,并延长蓄电池使用寿命。

基于虚拟矢量优选的FCS-MPC稳定性策略研究

为了提高并网逆变器有限集模型预测控制(FCS-MPC)方法中的稳定性问题,研究了基于Lyaponov准则的并网逆变器有限集模型预测控制大信号稳定性方法。首先建立数学模型,分析参数变化对预测误差的影响和大扰动导致的稳定性问题,接着提出采用虚拟电压矢量的Lyapunov控制器的有限集模型预测控制稳定性策略。利用Lyapunov控制器并结合考虑稳定性约束的目标函数增强系统抗扰动能力,虚拟电压矢量满足Lyapunov稳定性需求,同时改善控制性能,并设计有限集选取策略减少计算量。仿真和实验验证了所提方法在扰动及参数变化情况下控制性能和抗干扰能力。

O-Z源逆变器驱动PMSM的改进型FCS-MPC策略

针对O-Z源逆变器驱动永磁同步电机(PMSM)控制系统,在两相旋转坐标系下,提出一种改进型的有限状态控制集模型预测电流控制(FCS-MPC)策略。首先,结合变压器特点和ZSI拓扑结构,设计一种新型O-Z源逆变器(O-ZSI),并利用状态空间平均法建立O-ZSI的动态数学模型;其次,根据O-ZSI侧电容电压闭环以及PMSM系统输出功率前补偿来获得变压器激磁电感电流参考值,其与激磁电感预测电流值构建代价目标函数用来判断是否选取直通(ST)工作状态模式,以实现对O-ZSI直流侧的升压控制;然后,在O-ZSI处于非直通(NST)工作状态模式下,通过PMSM系统的定子电流预测方程来获得O-ZSI交流侧定子电压参考值,并与逆变器的8种开关状态所对应基本定子电压构建含有激磁电感电流项的代价目标函数,选择最佳开关状态来控制PMSM,从而提高PMSM系统的控制性能以及降低在线运算量;最后,仿真结果表明,本文所提控制策略不仅能实现对O-Z源逆变器的升压,而且能使O-ZSI驱动PMSM可靠稳定运行,同时系统具有良好稳态、动态性能。

基于改进FCS-MPC的APF电流跟踪控制方法研究

针对传统FCS-MPC电流跟踪精度低的问题,提出一种能够快速准确实现电流跟踪控制的改进FCS-MPC方法。将代价函数中补偿电流转换为输出电压快速获取最优开关状态,通过三矢量代替单矢量减小补偿电流脉动,同时加入两步预测对电流跟踪控制进行时滞补偿。仿真结果表明,改进FCS-MPC的电流跟踪控制精度提高,APF谐波抑制性能更好。

无人驾驶车辆路径跟踪混合控制策略研究

针对单一控制算法无法同时满足无人驾驶车辆对路径跟踪精度和控制器求解速度需求的问题,提出一种基于线性二次型调节器(LQR)和模型预测控制(MPC)的混合控制策略。该策略在低速工况下使用线性二次型调节器、在高速工况下使用模型预测控制算法进行路径跟踪控制,在此基础上设计基于有限状态机(FSM)的控制算法切换机制,并通过遗传算法(GA)对控制参数进行优化,基于CarSim和MATLAB/Simulink仿真平台对混合控制策略进行仿真验证,并进一步完成了实车试验。试验结果表明,所设计的混合控制策略能够在提高跟踪精度的基础上缩短计算时间,与单一控制算法相比,平均横向误差和平均航向误差分别减小了26.3%和39.6%,平均计算时间缩短了10.9%。

外包钢壳混凝土拱形桥塔节段拼装几何姿态预测研究

赣州市集结大桥主桥为外包钢壳混凝土拱形桥塔斜拉桥,为确保钢混组合拱形桥塔节段拼装精准合龙,采用MIDAS Civil软件建立拱形桥塔空间几何模型,分析外包钢壳和混凝土湿重对桥塔变形的影响,采用切线初始位移法对桥塔施工阶段位移进行预测,通过求解制造线形对桥塔待拼装节段进行预偏修正,并与实测数据进行对比。结果表明:外包钢壳能显著减小桥塔变形;施工阶段桥塔变形主要由混凝土湿重引起,临时支撑能有效减小混凝土浇筑产生的横向变形。基于切线初始位移法的几何姿态预测方法能有效预测桥塔拼装全过程几何姿态,实测成桥阶段桥塔各节段最大偏位为6 mm,小于施工控制要求,具有较高的实施精度,可保证成桥状态下桥塔几何姿态的准确性。

三相四开关容错逆变器的PMSM驱动系统FCS-MPC策略

针对三相四开关容错逆变器的永磁同步电机(PMSM)驱动系统,基于模型参考自适应(MRAS)观测器,提出一种有限控制集模型预测控制(FCS-MPC)策略。考虑温度变化对永磁磁链影响,采用MRAS技术,实现了对永磁磁链的在线辨识;同时考虑降低逆变器开关频率的需求,设计开关频率可优化的FCS-MPC系统目标函数。与常规FCS-MPC方法比较,本方法可以有效减小系统控制过程的计算量,与此同时,本方法中的电流反馈特性可对四开关逆变器直流母线电容分压不平衡形成的不利影响实现自动抑制。仿真结果表明,本方法能够保证四开关容错逆变器驱动的PMSM系统持续稳定运行、具有良好运行性能,并能明显降低逆变器功率管的开关频率。

应用滑模控制的四开关逆变器PMSM系统FCS-MPC策略

为了提高三相四开关逆变器永磁同步电机(PMSM)控制系统的性能,采用滑模控制方法,提出一种有限控制集模型预测控制(FCS-MPC)策略,并设计可以无抖振、单调收敛的滑模转速调节器.所设计的控制系统能够保证PMSM系统可靠稳定地运行,可抑制PMSM的电磁转矩脉动,改善三相定子电流波形效果,具备良好的转速跟随性能.仿真结果表明,与常规FCS-MPC方法相比,滑模转速调节器可以使电机加载时的转速跌落更小,并且转速能够更快恢复至参考值.所提出的FCS-MPC策略可以明显减小PMSM转矩脉动,降低三相定子电流总谐波失真(THD)值.当系统参数发生变化时,PMSM系统仍可平稳运行,三相定子电流能够保持良好的平衡性.

基于FCS-MPC的五桥臂UPQC电能质量补偿策略研究

针对容错模式下的统一电能质量调节器(Unified Power Quality Conditioner,UPQC),提出了一种五桥臂形式的新型拓扑结构,实现故障下的电能质量扰动综合补偿。在此基础上,对串联变流器和并联变流器进行统一建模,提出了一种基于有限集模型预测控制(Finite Control Set Model Predictive Control,FCS-MPC)的五桥臂UPQC控制策略。相比传统线性控制策略,所提算法构建了统一的预测模型以及整合优化的价值函数,实现串联变流器与并联变流器的协同控制,提高了两侧变流器的补偿精度、暂态性能以及响应速度,有效降低了控制算法的复杂度和参数调节难度,并具有较高的参数鲁棒性。仿真结果验证了所提算法的可行性和有效性。

基于FCS-MPC的电能质量综合调节器补偿策略研究

为提高统一电能质量调节器(unified power quality conditioner,UPQC)对电能质量扰动的补偿精度和响应速度,将有限状态模型预测控制(finite control set model predictive control,FCS?MPC)算法引入到电网侧和负载侧控制器中,通过对补偿量检测环节进行改进,构建预测模型,价值函数以及滚动优化方法,设计了一种基于FCS?MPC算法的UPQC电能质量扰动补偿策略,降低了算法的复杂度和参数调试的繁琐性,有效提高了控制算法的补偿精度和响应速度。该文应用MATLAB/Simulink仿真环境构建仿真模型与控制算法,分别针对电压暂降/暂升补偿、谐波补偿、非线性电流补偿、无功功率补偿、负序分量补偿进行了仿真分析,实验结果验证了所设计方法的正确性和可行性。

基于SAADR-PI的NPC三电平容错光伏并网逆变器FCS-MPC策略

为使并网逆变器在故障重构后仍向电网输送高质量电能,针对中性点钳位三电平逆变器容错拓扑,提出了基于自适应自抗扰比例积分控制器的有限控制集模型预测控制策略。首先,在直流侧电压控制环节引入自适应自抗扰比例积分控制器,以提高系统动态响应速度,增强系统鲁棒性能;然后,利用基于参考电压构造代价函数的并网模型预测电流控制策略,实现对参考电流的准确跟踪,并在代价函数中引入直流侧电容电压和开关频率约束项,以抑制中点电压不平衡问题,降低开关损耗;最后,在Matlab/Simulink中建立光伏并网系统模型并进行时域仿真。仿真结果表明,所提策略在稳态及光照阶跃变化时,直流侧电压调节具有更快的动态响应和更平滑的瞬态性能,且并网电流谐波含量低、波形质量好,可保证故障后依然能向电网输送高质量电能。

基于简化空间矢量调制的三电平整流器级联式无差拍控制策略

为解决有限控制集模型预测控制(FCS-MPC)运行过程中计算强度过大与计算时间过长的问题,提出了一种基于简化空间矢量调制的三电平整流器级联式无差拍控制策略,通过构建特定扇区选出最佳电压矢量。为建立精确的系统模型,深入分析三电平整流器,构建二维离散系统数学模型,基于无差拍控制理念设计了一套功率内环与电压外环的双环控制方案,并建立Luenberger观测器对电力扰动及负载变化进行精确估测与补偿,使无功功率与有功功率快速解耦和响应。结合上述系统架构,分别建立常规、单预测、简化预测FCS-MPC模型,并证明其等效性。分析不同约束变量对电压矢量决策的影响,并构建特定选择扇区设计简化的空间矢量调制策略。实验结果表明,所提控制控制策略能够在多重约束条件下改进性能,并且在保持控制效果不变的前提下,大幅度减少计算量。

永磁同步电机预测控制参数畸变影响分析

当永磁同步电机(PMSM)预测控制系统在高温等复杂环境中工作时,受电机齿槽效应、边端效应、饱和效应以及外部干扰的影响,电机参数如定子电阻、d轴电感、q轴电感、永磁体磁链常会发生畸变。针对上述问题,建立了PMSM的有限控制集模型预测电流控制(FCS-MPCC)模型,对不同参数畸变的影响进行分析,计算给出由畸变导致的d、q轴预测电流偏差。对参数畸变范围进行分区设置并依次施加在模型中。在不同畸变程度下,实验分析不同参数畸变对PMSM动、静态性能的影响,包括d、q轴电流、预测电流偏差、电磁转矩以及转速。

基于简化FCS-MPC的风电并网逆变器研究

三相风力发电并网逆变器的模型预测控制存在大量计算问题,导致控制指令的时间延迟,影响控制系统性能,严重阻碍系统应用。为克服上述难点,提出了一种在线简化有限控制集模型预测电流控制算法。该方法通过坐标变换构建αβ坐标下逆变器输出电流的预测模型,利用目标函数对逆变器输出的不同电压矢量进行评估,而无需使用脉宽调制模块。同时,结合电压空间矢量等效变换的原理,引入矢量扇区判断法,进而实现了预测控制过程的在线简化。最后,以带阻感负载三相并网逆变器为控制对象,建立了有限控制集模型预测控制仿真模型,分析了输出电流的稳态与动态性能。仿真结果验证了所提方法的有效性。