This paper proposes a new finite control set model predictive control (FCS-MPC) strategy that simultaneously evaluates two targeting control objectives (TCOs) including speed and currents in a single cost function, achieving high-performance single-closed-loop control structure. Besides, aiming at the calculation delay problem of the MPC controllers, a novel calculation delay compensation method by predicting the current variation within the delay time is proposed. In this paper, an improved machine model that is specially designed for the multi-objective FCS-MPC operation is illustrated at first. Then, a new cost function which can evaluate the tracking performance of speed and d-axis current and steady-state performance of q-axis current is developed. Compared to the conventional FCS-MPC approaches, extra speed controllers are not needed so that the proposed control topology becomes simpler. Then, in order to tune the weighting factors for the speed and currents in the cost function, an efficient handling strategy containing two implementation procedures, state variable normalization (SVN) and balance of state sensitivity to voltage alteration, is developed. Finally, a brand-new computation delay estimation and compensation technique based on dual sampling within a switching period is proposed to reduce the current and torque ripples during control process. Comparative simulation and experiments are conducted on a three-phase 1.5kW PMSM drive system.

This article investigates the water jacket and slot optimization of a water-cooling permanent magnet synchronous in-wheel motor. The optimization consists of the improvements of the water jacket heat dissipation and slot heat dissipation. In order to reduce the temperature difference between the water and water jacket wall, the impact of the water jacket configuration parameters and shapes are theoretically studied. According to the researches, the method for the water jacket optimization is proposed. A slot thermal model is established to optimize the thermal behavior in slots. The variations of the thermal performances with impregnation materials and slot configuration parameters are analyzed. On the basis of the analysis, this article presents a method for the thermal optimization. The validity of the method is supported by the finite element analysis, computational fluid dynamics and experiments.

Extensive solutions have been proposed to damp LCL filter resonance. However, the time delay caused by computation and modulation process aggravates the complexity of current loop analysis. In this paper, a generalized virtual impedance model for six kinds of commonly used active damping methods is proposed, and the physical meaning is established by introducing the metric of “damping factor”. To ensure system robustness in a wide range of grid conditions, a hybrid active damping strategy that combines inverter current feedback and capacitor voltage feedforward is proposed. Importantly, this method only requires inverter current and capacitor voltage sensors, which are the basic variables for over-current protection, power control and synchronization. The superposition theorem is also utilized to analyze the damping capability provided by parasitic resistances, current feedback loop and voltage feedforward loop. Finally, experimental results verify the feasibility and robustness of the proposed damping method.

In the past decade, extensive active damping solutions based on state variable feedback have been proposed to damp LCL resonance. In this letter, an innovative control strategy, which can achieve overcurrent protection, injected power control, and active damping at the same time, is proposed with the inverter-side current feedback only. Moreover, to avoid the mathematical limitations when solving characteristic roots of a third-order system, the damping-factor-based design method is proposed for the first time, by analyzing its equivalent circuit. The optimal damping factor, which is recommended to be positive and as large as possible, is searched to achieve superior resonance suppression effect. Finally, the proposed control and design method is verified by experimental results and shows good robustness both in stiff and ultraweak grid conditions.