永磁同步电机最优占空比模型预测转矩控制

发布时间：2018-11-03 19:31

【摘要】：永磁同步电机(Permanent Magnet Synchronous Motor, PMSM)因为结构简单,效率高等优点,逐渐在航空航天、数控机床等高性能调速场合得到了广泛应用。模型预测控制由于原理简单,便于处理非线性约束条件,因此具有很强的适用性。模型预测转矩控制(Model Predictive Torque Control, MPTC)策略是模型预测控制在直接转矩控制中的应用,但是两电平逆变器驱动的传统模型预测转矩控制只能选择六个固定方向上幅值恒定的电压矢量,并且每个控制周期只有一个电压矢量作用,存在较大的转矩和磁链脉动。基于占空比控制的模型预测转矩控制策略虽然可以减小转矩和磁链脉动,但是这种方法先选择电压矢量,然后再计算占空比,结合占空比后的电压矢量不能保证是全局最优。针对这一问题,本文在分析电压矢量幅值与转矩和磁链增量的基础上,提出了一种同时考虑转矩和磁链误差最小化的最优占空比模型预测转矩控制策略。该方法在选取电压矢量时,首先针对每一个电压矢量预先计算出使得下一时刻转矩和磁链与其给定值误差最小的占空比,再通过价值函数同时选取出最优电压矢量及其占空比的组合,并且在占空比计算过程中同时考虑了对转矩和磁链的控制。为了验证本文所提出的控制策略的可行性和有效性,在MALTAB/Simulink中对传统模型预测转矩控制、占空比模型预测转矩控制和本文提出的最优占空比模型预测转矩控制进行了仿真对比,最后在两电平逆变器驱动的永磁同步电机上进行了实验验证。实验结果表明占空比MPTC和最优占空比MPTC控制方法动态上保持传统MPTC的快速性的同时,稳态上减小了转矩和磁链脉动,而且最优占空比MPTC减小转矩和磁链脉动的效果最为明显。
[Abstract]:PMSM (permanent Magnet synchronous Motor) (Permanent Magnet Synchronous Motor, PMSM) has been widely used in aeronautics and astronautics, numerical control machine tools and other high performance speed control occasions because of its simple structure and high efficiency. Model predictive control has strong applicability because of its simple principle and convenient handling of nonlinear constraints. Model predictive torque control (Model Predictive Torque Control, MPTC) strategy is an application of model predictive control (MPC) in direct torque control (DTC). However, the traditional model of two-level inverter drive can only select six voltage vectors with constant amplitude in a fixed direction, and each control period has only one voltage vector, which has a large torque and flux ripple. Although the torque control strategy based on duty cycle control can reduce the torque and flux ripple, this method selects the voltage vector first, then calculates the duty cycle, and the voltage vector after duty cycle can not be guaranteed to be the global optimal. In order to solve this problem, based on the analysis of voltage vector amplitude, torque and flux increment, an optimal duty cycle model predictive torque control strategy is proposed, which considers the minimization of torque and flux error simultaneously. In selecting the voltage vector, the duty cycle of the torque and flux at the next moment and the minimum error between the flux and the given value are calculated in advance for each voltage vector. The optimal voltage vector and its duty cycle are selected simultaneously by the value function, and the control of torque and flux is considered simultaneously in the duty cycle calculation. In order to verify the feasibility and effectiveness of the proposed control strategy, the traditional model predictive torque control is used in MALTAB/Simulink. The duty cycle model predictive torque control is compared with the optimal duty cycle predictive torque control proposed in this paper. Finally, the simulation results are verified on the permanent magnet synchronous motor (PMSM) driven by two-level inverter. The experimental results show that the control methods of duty cycle MPTC and optimal duty cycle MPTC dynamically maintain the rapidity of traditional MPTC, and at the same time reduce the torque and flux ripple in steady state, and the effect of the optimal duty cycle MPTC on reducing torque and flux ripple is most obvious.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM341

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