一种基于电机模型预测的三电平死区补偿方法

分析了三电平电压型逆变器死区效应产生的机理,针对电流采样延时和寄生电容影响而导致死区补偿不准的问题,提出了一种基于电机模型预测的三电平电压型逆变器死区补偿方法。该方法首先建立了三电平电压型逆变器驱动异步电机的数学模型,并根据该模型和瞬时电流采样值,计算出实际瞬时电流的预测值,然后将电流预测值和器件开关状态代入该模型计算出准确的补偿时间,实时的对补偿电压进行调整。最后,改进算法在7.5 k W感应电机变频调速系统上进行了实验验证,结果证明了该补偿方法能有效改善电机的电流波形。

基于预测模型的异步电动机间接转矩控制系统

本文介绍了间接转矩控制(ISC)的基本原理,分析了基于异步电动机预测模型的间接转矩控制系统的组成及实现方法,给出了ISC的控制算法和电机预测模型,以及该系统的实时控制实验结果。实验结果表明,ISC 控制策略能够有效地改善直接转链矩制系统的低速特性。若ISC和DTC相互配合,可以实现异步电动机直接转矩控制系统在全速范围内的高性能运行。

基于MMC的电机驱动新型控制方法

针对电机在低频工况下出现的电容电压波动、桥臂环流等问题,提出了一种无权重系数的模块化多电平变换器驱动模型预测控制策略。在假设子模块电容电压均衡的前提下,建立相电流目标函数并求取最优解,通过引入补偿电平数,实现对环流的优化控制。同时为改善传统排序均压控制算法速度较慢的不足,优化了现有SM电容均压控制策略,引入保持因子,并依据理想情况下MMC的电容电压规律,进行归并排序,保证了MMC中各SM电容电压的均衡。通过仿真验证了所提方法能有效实现对电机的控制。

带扰动补偿的离散滑模SPMSM模型预测电流控制

针对永磁同步电机模型预测电流控制的调速系统往往会出现运行不稳定,在受到外部扰动时速度波动较大这一现象,提出了带负载扰动观测的离散滑模控制永磁同步电机模型预测电流控制方法.在表面式永磁同步电机模型预测电流控制算法研究的基础上,设计了离散滑模速度控制器取代比例—微分(PI)调节器,抑制了超调,提高了系统的启动性能.提出了离散滑模扰动观测器并对负载进行前馈补偿,有效的抑制了外部的扰动,提高了系统的鲁棒性.通过仿真验证了该控制策略可提高系统的动态性能和稳态精度.

Field-weakening control system of induction motor based on model prediction

Considering the actual demand for high-speed operation of induction motors in industrial occasions,the characteristics of induction motors in different regions are analyzed,especially the field weakening characteristics of induction motors in high-speed operation are studied.A field weakening control method of induction motor based on model predictive control(MPC)algorithm is proposed,which can predict the future state of the controlled object,and then obtain the optimal control variables by colling optimization.The simulation results show that the field-weakening control method based on MPC algorithm has faster response speed,stronger robustness and better control performance than the traditional control methods.

Predictive current control system of PMSM based on LADRC

For a permanent magnet synchronous motor(PMSM)model predictive current control(MPCC)system,when the speed loop adopts proportional-integral(PI)control,speed regulation is easily affected by motor parameters,resulting in the inability to balance the system robustness and dynamic performance.A PMSM optimal control strategy combining linear active disturbance rejection control(LADRC)and two-vector MPCC(TV-MPCC)is proposed.Firstly,a mathematical model of a PMSM is presented,and the PMSM TV-MPCC model is developed in the synchronous rotation coordinate system.Secondly,a first-order LADRC controller composed of a linear extended state observer and linear state error feedback is designed to reduce the complexity of parameter tuning while linearly simplifying the traditional active disturbance rejection control(ADRC)structure.Finally,the conventional PI speed regulator in the motor speed control system is replaced by the designed LADRC controller.The simulation results show that the speed control system using LADRC can effectively deal with the changes in motor parameters and has better robustness and dynamic performance than PI control and similar methods.The system has a fast motor speed response,small overshoot,strong anti-interference,and no steady-state error,and the total harmonic distortion is reduced.

Model predictive flux control of permanent magnet synchronous motor driven by three-level inverter based on fine-division strategy

Aiming at the difficulty of setting the weight coefficient in the value function of model predictive torque control(MPTC)for permanent magnet synchronous motor(PMSM)driven by three-level inverter,a fine-division model predictive flux control(MPFC)method is proposed.First,establish a mathematical model between the motor torque and the stator flux linkage according to the mathematical equations of PMSM.Thus,the control of the motor torque and stator flux linkage in the MPTC is transformed into the control of a single stator flux linkage vector,omitting the cumbersome weight setting process in the traditional MPTC.The midpoint potential control strategy is proposed,which uses the characteristics of redundant small vectors to balance the midpoint potential.After that,a fine-division strategy is proposed,which effectively reduces the number of candidate vectors and the computational burden of the system.Finally,the proposed MPFC is compared with MPTC by simulation.The results show that the proposed fine-division MPFC effectively reduces the system calculation,and has the advantages of simple principle and better dynamic and steady-state control performance.The feasibility of the control strategy is verified.

Model predictive torque control of permanent magnet synchronous motor system driven by matrix converter

Employing matrix converter （MC） as driving mode, the strategy of model predictive torque control （MPTC） is proposed for three phase permanent magnet synchronous motor （PMSM） system. MC is applied instead of conventional AC DC AC converter to increase the power factor （PF） of the system input side. MPTC is used to select optimal voltage space vector to enable the system to have satisfactory torque and flux control effect. The resultant MPTC strategy not only makes the MC fed PMSM system operate reliably and have perfect control performance, but also makes the PF of the system input side be 1. Compared with direct torque control （DTC）, the proposed MPTC strategy guarantees that MC fed PMSM has better command following characteristics in the presence of variation of load torque and tracking reference speed. Simulation results verify the feasibility and effectiveness of the proposed strategy.

Load Torque Compensator for Model Predictive Direct Current Control in High Power PMSM Drive Systems

The widely used cascade speed and torque controllers have a limited control performance in most high power applications due to the low switching frequency of power electronic converters and the convenience to avoid speed overshoots and oscillations for lifetime considerations. Model Predictive Direct Current Control （MPDCC） leads to an increase of torque control performance taking into account the discrete nature of inverters but temporary offsets and poor responses to load torque variations are still issues in speed control. A load torque estimator is proposed in this paper in order to further improve dynamic behavior. It compensates the load torque influence on the speed control setting a feed forward torque reference value. The benefits are twice; the speed controller reaches the speed reference value without offsets which would need to be compensated by an integrator and a better response to load torque variations is obtained since they are detected and compensated leading to small speed variations. Moreover, the influence of pararneter errors and disturbances has been analyzed and limited so that they play a minor role in operation.