The permanent-magnet synchronous motor (PMSM) with high efficiency and high power density is now attracting more and more attention, which could be largely used in occasions supplied by limited energy and restricted by weight or capacity, for example, the electric vehicles and the solar unmanned aerial vehicles. In this paper, the electromagnetic and thermal issue of a PMSM with high efficiency and high power density has been researched. We comparatively analyzed the efficiency and the power density characteristics of the outer-rotor PMSM. The influence of electromagnetic parameters on efficiency and power density has been analyzed. Through researching the Halbach array, we got the maximum output torque and the minimum core loss. Because of the inner stator, the heat generated by the winding has much trouble to dissipate. The thermal-transfer structure based on the heat pipe has been proposed, which could decrease the temperature of windings by more than 180 °C shown by finite-element analysis results. Finally, the prototype motor has been made, and the experimental results are consistent with the analysis, which verified the correctness of the theory.

The air gap of tubular linear motors moves linearly, causing heat transfer states of the motor to alternate repeatedly. Thus, the heat transfer coefficients of the mover inner surface and the stator outer surface vary constantly. In this paper, the combination model of the thermal circuit and temperature field is established to calculate the transient temperature rise of a tubular linear motor with short and movable primary. The equivalent thermal circuit model of the moving air gap and the temperature field models of the primary (also named as mover) and secondary (also named as stator) are established. The thermal boundary conditions and the correlations among them are analyzed. By this method, the complicated variation and distribution of the heat transfer coefficients are gained. Moreover, the transient temperature rise of the motor is calculated. This method takes advantage of the flexibility of the thermal circuit method and the accuracy of the temperature field method. The calculated and tested results of the prototype are compared and analyzed.

In this article, an augmented generalized proportional–integral observer (GPIO) is presented to estimate and then compensate for the disturbance/uncertainty both existing in the electrical and mechanical subsystems of the motion stage driven with an air-bearing permanent-magnet linear synchronous machine (PMLSM). First, a modeling method for the two subsystems, considering the disturbance/uncertainty and the integration of the measured outputs as extended states, is proposed. Second, to reduce the coupling effect of the observer gains and the measurement noises on the disturbance estimation dynamics, an augmented GPIO is designed and its convergence theorem is given. Furthermore, with the extended models, the augmented GPIO is developed for both the compensation of parameter mismatch in the predictive current control (PCC) and the force ripple estimation/suppression of the PMLSM. Finally, with the augmented GPIO, an improved PCC robustness test with time-varying parameter mismatch is conducted both in the single-current closed loop and the double-current closed loop with cascade position-current control. A simple and practical parameter-tuning procedure is also analyzed in detail for both the electrical and mechanical subsystems. The position trajectory tracking error is reduced largely with accurate and real-time force ripple compensation. Experimental setup and results are provided to validate the effectiveness of the proposed design method.

Traditionally, straggering the primaries of the double-sided permanent magnet linear synchronous motor (DS-PMLSM) is beneficial in helping to reduce the detent force caused by the longitudinal end effect, but leading to a reduction of the average thrust. To overcome this disadvantage, this paper provides a novel DS-PMLSM, which adopts the structure of staggering two primaries and rearranging windings. Firstly, the characteristics of the voltage and detent force are analyzed theoretically and verified by finite element (FEM) simulations. The inductance, thrust and normal forces are then compared with the traditional DS-PMLSM. Furthermore, the geometrical parameters are optimized to improve the thrust. Finally, one DS-PMLSM prototype is tested. The detent force and back EMF tested results verify the effectiveness of the topology proposed in this research.