Slotless Permanent Magnet Synchronous Motor Research Articles

Design and Load Test of High Speed Slotless Permanent Magnet Synchronous Motor with Round-Wire Air-Core Distributed Winding

Design and Load Test of High Speed Slotless Permanent Magnet Synchronous Motor with Round-Wire Air-Core Distributed Winding

Design and Load Test of High Speed Slotless Permanent Magnet Synchronous Motor with Round-Wire Air-Core Distributed Winding

Design and Load Test of High Speed Slotless Permanent Magnet Synchronous Motor with Round-Wire Air-Core Distributed Winding

A Study on the Improvement of Torque Density of an Axial Slot-Less Flux Permanent Magnet Synchronous Motor for Collaborative Robot

In this paper, an axial slot-less permanent magnet synchronous motor (ASFPMSM) was designed to increase the power density. The iron core of the stator was replaced with block coils, and the stator back yoke was removed because 3D printing can provide a wide range of structures of the stator. The proposed model also significantly impacts efficiency because it can reduce iron loss. To meet size and performance requirements, coil thickness and number of winding layers in the block, the total amount of magnet, and pole/slot combinations were considered. The validity of the proposed model was proved via finite elements analysis (FEA).

Comparison of Electrified Aircraft Propulsion Drive Systems with Different Electric Motor Topologies

Electric aircraft propulsion is a growing research area that looks into achieving propulsion through fully electric or hybrid electric systems while achieving low emissions. The system-level benefit gained by different electric and hybrid-electric propulsion schemes depends heavily on the performance of system-level components in the electric drive-train, including the electric motor, gear box, motor drive, protection systems, as well as the thermal management system. When comparing motor topologies, it is important to understand performance measures such as efficiency and specific power on a drive system level. Many different motor types have been qualitatively compared and can be found in the literature. To guide appropriate component selection, this paper presents details of a quantitative study for a given electric propulsion drive system. A Pareto optimal front for a notional drive system of a 1.5 MW electrical propulsor with different motor types is generated and compared. An optimization algorithm coupled with an electromagnetic finite element analysis software tool was used to optimize the induction motor, switched reluctance motor, wound rotor synchronous motor, permanent magnet synchronous motor (PMSM), slotless PMSM, permanent-magnet-assisted synchronous reluctance motor, brushless DC motor, and brushless doubly fed reluctance motor types for efficiency and specific power. Overall advantages considering system-level efficiency, specific power, and a few other key metrics such as origin of losses, cooling complexity, manufacturing tolerance, and fault tolerance are discussed. This gives an indication of the relative performance of different motor types and confirms the overall advantage of PM motor topologies in aircraft propulsion.

Impact of Manufacturing Tolerances on a Low-Reactance Slotless PM Synchronous Machine

This paper presents the impacts of manufacturing tolerances on a 1 MW slotless permanent magnet synchronous motor used in an aircraft propulsion system. The motor was designed using multiphysics analysis of electromagnetics, mechanical structure and thermal analysis to obtain a high torque density. It has several governing characteristics, including a Halbach permanent magnet arrangement, slotless stator windings, an outer rotor, lower reactance and a high current density. Since the current density of this design is high, the existence of circulating currents should be considered for safe operation under different levels of manufacturing tolerances. In particular, the low reactance of the motor and the slotless structure greatly contribute to increase the circulating current. Therefore, this paper analyzes various factors affecting the circulating current such as eccentricity and imbalanced windings. Finally, an analytical model is used to calculate magnetic and electric loading, and non-linear finite element analysis are applied and compared to obtain the machine performance.

Electric Propulsion With the Sensorless Permanent Magnet Synchronous Motor: Model and Approach

In this paper, a rotor position estimator for the sensorless permanent magnet synchronous motor (PMSM) is developed. The proposed approach exploits the time-scale separation between the electrical and mechanical time constant of the PMSM to formulate a linear observer. The observer produces accurate rotor angle estimates in steady-state and transient, and is attractive for electric propulsion applications due to its independence from mechanical parameters such as load torque, inertia, and friction. The sensorless strategy is well-suited to the nonsaturating slotless PMSM, but the demonstrated robustness of the observer to modeling uncertainties allows for application to slotted construction as well. Experiments are conducted to confirm the effectiveness of the proposed approach.

Slotless permanent magnet synchronous motor operation without a high resolution rotor angle sensor

An implementation for sinusoidal current control of a slotless permanent magnet synchronous motor (PMSM) with discrete Hall sensor position feedback is presented. To estimate the rotor position of the slotless PMSM, a flux estimation technique is used that takes advantage of the slotless machine's characteristically low inductance to limit flux estimation error. The rotor position is estimated using a reference model and the measured phase currents and voltages. At startup and very low speeds, discrete Hall sensors are used to limit the position estimation error to approximately /spl plusmn/30 electrical degrees and to prevent the flux estimators from drifting due to measurement noise and offset. The proposed sinusoidal control method reduces the torque pulsations present when Hall sensor position feedback alone is used and eliminates the need for high-resolution rotor angle sensors. The proposed control strategy is applied to a slotless PMSM drive system and implemented using a digital signal processor (DSP). Experiments are carried out for the system and the results demonstrate the effectiveness of the control.