Investigation of the Cooling and Thermal-Measuring System of a Compound-Structure Permanent-Magnet Synchronous Machine

Abstract:The accurate information of the initial rotor position is very critical for successful starting of the Surface-mounted Permanent Magnet Synchronous Motor (SPMSM). In order to solve the problems of low accuracy and unreliability in the conventional estimation strategy, in this paper, an improved initial rotor position estimation strategy without any position sensor for SPMSM at standstill is proposed based on rectangular pulse voltage injection. In the work, when the second series of pulse voltages were applied. By the ways of strengthening the effect of weakening or strengthening magnetic fields and increasing the difference between each current of the vector. The improved strategy enhanced reliability and raised the initial position estimation accuracy from 7.5° to 1.875°. The improved strategy does not need any additional hardware. Experimental results demonstrate the validity and usefulness of the improved strategy.

Section: Introductionmentioning

confidence: 99%

Sensorless Speed Control with Initial Rotor Position Estimation for Surface Mounted Permanent Magnet Synchronous Motor Drive in Electric Vehicles

Wang

Huang

et al. 2015

“…However, considering that the high speed machine used for FES system should start easily and run stably, the machine should have good torque performance. In addition, considering that FES system should have low iron loss at no load, air-gap magnetic field harmonics, which can be reflected by the back electromotive force (EMF) harmonics, will cause high losses in the stator core, rotor core and permanent magnets at high speed [34][35][36][37]. Furthermore, when the FES works under discharging or charging conditions, the back EMF waveform must also be closer to a sine wave and have as few harmonics as possible.…”

Section: Introductionmentioning

confidence: 99%

Research on the Torque and Back EMF Performance of a High Speed PMSM Used for Flywheel Energy Storage

Zhao

et al. 2015

Abstract:Due to advantages such as high energy density, high power density, rapid charge and discharge, high cyclic-life, and environmentally friendly, flywheel energy storage systems (FESs) are widely used in various fields. However, the performance of FES systems depends on the performance of a high speed machine, therefore, the design and optimization of a high efficiency and high power density machine are very crucial to improve the performance of the whole FES system. In this paper, a high speed permanent-magnet synchronous machine (PMSM) is researched. Considering the requirement of low torque ripple in low speed and loss caused by back electromotive force (EMF) harmonics, the electromagnetic performance is improved from points of view of slot/pole matching, magnetic-pole embrace with the finite element method (FEM). Furthermore, the magnetic-pole eccentricity, the slot opening, the thickness of PM and air-gap length are also optimized with Taguchi method. The electromagnetic performance, such as torque ripple, cogging torque, average torque and back EMF wave are much improved after optimization. Finally, experiments are carried out to verify the calculated results.

“…Because of the small size of insulating varnish and gap, an equivalent model is used to simulate the actual heat conduction in the stator slot. The equivalent model consists of three parts: solid copper conductor, equivalent insulation and slot insulation [31]. The solid copper conductor is located in the middle of the slot, and its area equals that of total copper wires in one slot.…”

Section: Thermal Conductivitymentioning

confidence: 99%

Thermal Analysis of a Novel Cylindrical Transverse-Flux Permanent-Magnet Linear Machine

Zhang

Jin

et al. 2015

This paper presents a novel staggered-teeth cylindrical transverse-flux permanent-magnet linear machine (TFPMLM), which aims to improve the power factor and force density. Due to the compact structure and high performance requirement, thermal problems should be seriously considered. The three-dimensional (3-D) temperature field model is established. The determination of convection heat transfer coefficients is discussed. Equivalent thermal conductivities of stator core and winding are given to simplify the analysis. With the thermal effect of the adhesive coatings among permanent magnets (PMs) and mover yoke taken into account, the temperature field distribution and variation rules of the TFPMLM are obtained using the finite volume method (FVM). The influences of slot filling factor and air flow velocity on the temperature field distribution are analyzed. It is found that the hottest spot of the TFPMLM appears in the middle of the end winding; and there is no risk of demagnetization for PMs.