Abstract

Due to importance of duty cycle based model predictive torque control (MPTC), it has been accepted as an effective and common alternative control strategy for industry. Since its major drawback is great dependency on duty ratio parameter, the robustness and the complexity of control system has been respectively decreased and increased. A duty-ratio set considering limited members can be replaced with continuous and dependent parameters form duty cycle relationship. Hence, this paper proposes a new and applicable discrete duty cycle control strategy to reduce both the torque and flux ripples appeared in MPTC method. In the proposed method, after preselecting around half of all admissible voltage vectors based on the torque sign or speed variation and the stator flux position, two duty ratios have just been selected for the preselected active voltage vectors. These two duty ratios are achieved based on the equivalent voltage concept with independent motor parameter. Then, the model predictive control method is employed to select the optimum active voltage vector and its relevant duty ratio among the reduced feasible voltage vectors which reduces both the flux and torque ripples, especially in low speed ranges. The simulation results have confirmed the performance of the proposed method in order to reduce the torque and flux ripples, and the experimental results have accordingly validated its performance. Since the number of voltage vectors and duty ratios is significantly decreased, the execution time of the proposed method is further reduced, and virtually worked with a constant switching frequency for all speed ranges.

摘要

由于基于占空比的模型预测扭矩控制 (MPTC) 的重要性，它已被视为一种有效且通用的工业替代控制策略。由于其主要缺点是对占空比参数的依赖性很大，因此控制系统的鲁棒性和复杂性分别降低和增加。考虑有限成员的占空比集可以用连续的和依赖的参数代替，形成占空比关系。因此，本文提出了一种新的适用的离散占空比控制策略，以减少 MPTC 方法中出现的转矩和磁通脉动。在所提出的方法中，在基于转矩符号或速度变化和定子磁通位置预选所有允许电压向量的大约一半之后，刚刚为预选的有源电压矢量选择了两个占空比。这两个占空比是基于具有独立电机参数的等效电压概念实现的。然后，采用模型预测控制方法在减小的可行电压矢量中选择最佳有功电压矢量及其相关占空比，从而减小磁通和转矩脉动，尤其是在低速范围内。仿真结果证实了该方法在减小转矩和磁通脉动方面的性能，实验结果也相应地验证了其性能。由于电压矢量和占空比的数量显着减少，所提出方法的执行时间进一步减少，