Jibin Zou

Optimization of split ratio to design the PM brushless DC motor

The split ratio of the permanent magnet motor is one of the most important design parameters. It can not only influence the motor electrical torque and efficiency, but also can influence the motor thermal behavior. According to the high torque, short duty permanent magnet brushless motor, the thermal behavior should be investigated carefully. In this paper, the influence of the split ratio on the motor characteristics is investigated by field and circuit coupling finite elements analysis firstly. Then the influence of the split ratio on the motor thermal behavior of is analyzed, emphasis on the high torque short duty operation. The optimal design results are verified experimentally.

The analysis for new axial variable reluctance resolver with air-gap complementary structure

A new kind of a couple-pole axial variable reluctance resolver is introduced in this paper, which is compact, small in size and has huge anti-interference ability, etc. Being special axial structure, the new type reluctance resolver has strong ability than any other kinds of variable reluctance resolvers. The variable reluctance principle of this new resolver is different from the traditional reluctance resolvers because the reluctance of this resolver is changed by varying the coupling area between the rotor and the stator. 3D FEM time stepping method is used in this article to analyze the character of EMF produced by two signal windings. At the same time, every part of magnetic structure is designed based on the simulation result to minimize errors.

Rotor eddy-current loss of permanent magnet machine in brushless AC and DC modes, used for deep-sea HUV's propeller

Permanent magnet brushless motor used for deep-sea Human Occupied Vehicles (HUVs) propeller was studied in this paper. Based on analyzing the influences of waveform of phase current on flux density in air gap, rotor eddy-current losses were determined in BLAC and BLDC modes. This paper proposed that rotor loss is the minimum in BLAC mode. In BLDC mode, with optimal commutation advance angle (20°), rotor loss is the lowest. Finally the temperature distribution of the motor was gained considering the rotor eddy-current loss.

Current limit strategy for BLDC motor drive with minimized dc-link capacitor

Brushless dc (BLDC) motor drive system employing minimized dc-link capacitor is becoming popular due to compactness and long life. With low capacitance, the dc bus voltage will be pumped up severely if regenerative current flows back, the occurrence of which is common in conventional current limit operation. To avoid the damage caused by oversize pumping-up voltage, a current limit strategy without regenerative current is necessary. This paper proposes a novel current limit strategy for BLDC motor drive with minimized dc-link capacitor. The realization based on single current sensor and software comparison is presented in detail. At last the proposed strategy is verified by simulation and experiment.

Influence of periodic carrier frequency modulation on low frequency electromagnetic interference of permanent magnet synchronous motor drive system

This paper introduces periodic carrier frequency modulation (PCFM) to permanent magnet synchronous motor (PMSM) drive system to improve the electromagnetic compatibility. PCFM is introduced to reduce low frequency CM conducted EMI of PMSM drive system. Simulations and experimental results verify that sinusoidal and sawtooth PCFM can reduce CM conducted EMI of PMSM drive system effectively. Furthermore, sawtooth PCFM is more effective than sinusoidal PCFM in suppressing CM conducted EMI of PMSM drive system. Moreover, the reduction about CM conducted EMI of PMSM drive system by sinusoidal and sawtooth PCFM improves with the increase of spreading frequency widths.

Analysis and design of FSCW SPM machines for a given constant power region

This paper focuses on the design and analysis of fractional-slot concentrated windings synchronous permanent magnet machines for a given constant-power speed ratio using FEM. The constant power ability is concerned with magnet flux linkage, synchronous inductance, and phase voltage. The main dimensions and turn number of the machine are obtained on the basis of electric loading, magnetic loading, winding factor, and torque. Experimental measurements are also performed to validate the results obtained by FEM.

Optimization of cogging torque and back-EMF for a 16-pole/24-slot IPM machine

This paper analyzes the winding configuration and gap flux density of a 16-pole/24-slot IPM machine, and reduces the EMF harmonics and cogging torque with the methods of optimizing the surface of the rotor core and corner cut associatively by FEA. It will be seen that the method used by this paper is better than the rotor optimization method used alone. A prototype machine is manufactured and validates effectiveness of the optimization.

The effect of magnet depth on magnet eddy current loss in 16-pole/24-slot IPM machines

PMSMs with concentrated windings gain more and more interests due to the very short end winding and advantages in the production process, for which they are desirable for wind power generations, electric vehicles and torque propulsion and so on. However, concentrated windings produce a rich spectrum of flux density harmonics, which rotate asynchronously with respect to the rotor, inducing eddy current loss in the rare-earth PMs.

Investigation of electromagnetic torque in permanent magnet synchronous machines with fractional slot concentrated winding

Electric Machine is an energy conversion device, which realizes the electrical energy and mechanical energy convert to each other through electromagnetic power or electromagnetic torque. Electromagnetic torque is an important medium for this conversion progress. Thus accurate estimation or model of electromagnetic torque is desired for designing and analyzing the electric machines. Furthermore electromagnetic torque estimation for servo control and torque ripple depress, where the model of torque is utilized directly or indirectly, is urgent.

Unbalanced magnetic forces in tubular transverse flux linear machine with diametrically asymmetric magnets

This paper investigates the characteristics of the unbalanced magnetic force and the thrust force in asymmetric 6-slot/6-pole transverse flux permanent magnet linear machine with diametrically asymmetric magnets by using the three-dimensional finite element method. In order to eliminate the unbalanced magnetic force, a new topology, i.e., symmetric magnets of a 6-slot/6-pole TFPMLM is proposed. Furthermore, the analysis and comparison results of two proposed machine are illuminated in order to improve the thrust force and eliminate the unbalanced magnetic force.