Coreless Permanent Magnet Synchronous Motor Research Articles

Design, Analysis and Experimental Verification of a Coreless Permanent Magnet Synchronous Motor

The paper presents a new cost-effective magnetic circuit structure of a coreless permanent magnet synchronous motor (PMSM) with 16 poles and 12 coils for a mass production fan drive unit. 2D and 3D numerical models of the coreless PMSM were developed. Optimisation calculations were carried out using the field model of the machine. Multistage calculations were performed using the professional FEM package, ANSYS Maxwell and the author’s proprietary finite element method (FEM) code. On the basis of the conducted tests and analysis of the obtained results, the “optimal” magnetic circuit structure of the PMSM motor was selected. The prototype motor was subjected to measurement to verify the developed models and the proposed design approach that takes advantage of finite element analysis (FEA).

Development of a Modular Controller to Minimize Current Ripple in Low Inductance Coreless Permanent Magnet Motor

In this paper, a development of a modular controller to minimize current ripple in a low inductance coreless permanent magnet synchronous motor (CPMSM) is described. Based on individual modules, the controller uses a 60 degree commutation scheme instead of the conventional 120 degree. The neutral point of the motor’s windings is connected to an intermediate voltage level provided by a capacitor bank relative to the DC power bus. This feature allows the utilization of a single current sensing point that is used to regulate the motor’s torque by hysteretic current level control. With this simplification of the control strategy it was possible to use a single Programable Logic Device (PLD) to implement all the processing in the controller. The controller was built and tested, and the results showed efficient and smooth operation of the motor.
 Keywords: Current ripple, Permanent magnet motor, Low inductance

Development of a Coreless Permanent Magnet Synchronous Motor for a Battery Electric Shell Eco Marathon Prototype Vehicle

Abstract This paper describes the development of an in-wheel Coreless Permanent Magnet Synchronous motor designed and built for the participation of the Aero@UBI team in Shell Eco-Marathon competition where a low power and highly efficient motor was needed. The design of the motor for this competition is presented and the adopted concepts explained. The conjunction of the concepts embedded in the design made this motor one of a kind. The use of Litz wire and a single wave winding turn allow the possibility to configure the motor’s constant. The model used in the motor’s design is presented. The motor was built, and the experimental tests data are given for the motor. The motor was tested with two different controllers and the results show the high efficiency of the presented motor.

Modified MPC Algorithm for NPC Inverter Fed Disc Coreless Permanent Magnet Synchronous Motor

The disc coreless permanent magnet synchronous motor (DCPMSM) has suffered some stringent current ripple for its small phase inductance. The metal-oxide-semiconductor field-effect transistor (MOSFET)-based inverters can reduce this ripple by the help of its high switching frequency. However, due to the low voltage stress, the MOSFET is not suitable to the high dc-link voltage applications. A three-level neutral point clamped inverter is proposed to drive DCPMSM in this paper. Moreover, a modified finite-control-set model-predictive control (FCS-MPC) algorithm is proposed to reduce the calculation and the neutral-point voltage ripples. Comprehensive simulation and experiments show that the proposed method can repress the current ripple and the neutral-point voltage ripple effectively.

Predictive Instantaneous Torque Control for Disc Coreless Permanent Magnet Synchronous Motor With the Current Source Chopper

The disc coreless permanent magnet synchronous motor has several advantages, such as strong overload capacity, zero cogging torque, sinusoidal back EMF, and linear parameters. The motors tend to have low inductance because of the coreless structure. There is a stringent current ripple in the motor winding that produces unacceptable torque ripple if driven from conventional drivers with a pulse width modulation control method based on voltage source inverter. To solve this problem, a predictive instantaneous torque control method based on a current source chopper is proposed in this paper. As electromagnetic torque depends on the stator current magnitude and rotor angle, the relationship between these two variables is discussed. The current amplitude and switch state of the inverter are computed according to the rotor position, and the stator current magnitude can be regulated in real time by the current source chopper. The proposed control system can dramatically reduce the current ripple caused by low inductance and the validity of the proposed control method is verified by simulation and experimental results.

Permanent Magnets Design and Magnetic Field Analysis of Multi-disc Coreless Permanent Magnet Synchronous Motor

This paper presents a new multi-disc coreless permanent magnet synchronous motor whose permanent magnets are arranged in the “Halbach array”. Unit motor combined structure is adopted to simplify processing technology of the motor. Airgap magnetic flux density is increased taking advantage of high remanence and coercive force of NdFeB permanent magnet material and high gathering magnetism function of Halbach array. This also makes coreless motor possible. The structure and the characteristics of the motor using Halbach array are also introduced. The FEM analysis has been done to build the mathematical model and study the magnetic field characteristics of the motor. And finally the interrelated design parameters of permanent magnet and arrangement between unit motors are determined according to the results of die FEM analysis.

Simplified Calculation of Open Domain of Magnetic Field in Engineering

Mass electromagnetism phenomena occur in open domain. But because of the difficulty of calculation, open domain problems are often simplified as equivalent model in the finite space in order to save time of modeling and analyzing in the computer. Taking a disk coreless permanent magnet synchronous motor (PMSM) as an example, the FEM analysis is done to simplify open domain of magnetic field. Aiming at a difficult problem of the modeling and solving to the open domain of magnetic field, it is very important to reduce fact domain effectively. The FEM analysis has been done to prove that the method reducing the open domain into the smallest domain could obtain approximately the accurate results, at the same time the EMS memory and the time are reduced obviously. So the intention of simplification is achieved.