Tae-Chul Jeong

Torque Density Elevation in Concentrated Winding Interior PM Synchronous Motor With Minimized Magnet Volume

Permanent magnet (PM) synchronous motors (PMSMs) have been used to drive a number of vehicles. They have high torque density, high efficiency, and a wide speed range. However, the high cost of PMs is disadvantageous. This paper presents a technique for increasing the torque density by modifying the shape of the PMs and minimizing the magnet volume. The PM characteristics such as flux density, demagnetizing force, PM energy product, and the air-gap flux density are represented by a lumped magnetic equivalent circuit when the thickness and width of the PM are increased for the same volume but with different shapes. The torque, torque ripple, core loss, magnet loss, and efficiency of three interior (IPMSM) models designed by the proposed method are compared by finite element analysis. In addition, the demagnetization of the PM due to high temperature, maximum torque load angle, and an adverse field is analyzed. Finally, the analysis result is compared with that of the experiment to verify the proposed model.

Current Harmonics Loss Analysis of 150-kW Traction Interior Permanent Magnet Synchronous Motor Through Co-Analysis of

In this study, the losses due to the time-harmonic current in a permanent magnet synchronous motor (PMSM) are calculated through a co-analysis of the time harmonics using a space vector pulse width modulation (SVPWM) inverter. PMSM is typically used as a control motor. The current in the PMSM contains harmonics because the inverter voltage is not sinusoidal, and as a result, losses occur. These losses have a negative effect on the synchronous motor performance, which is vulnerable to heat. Therefore, for efficiency and performance evaluation of the PMSM, it is necessary to consider a co-analysis of the time harmonics. In this study, we present a co-analysis method for a PMSM designed for buses and compare the analysis results with those of the current source analysis in order to verify the significance of the co-analysis. In particular, it is observed that the difference in the eddy current losses in the PM individually determined with the current source analysis and co-analysis is approximately 500%. For validating this study, the experimental equipment is established, and it can be confirmed that the experimental results are close to the co-analysis results.

d\hbox{-}q

The design of a motor with a large armature reaction, such as the electric vehicle traction motor, can be implemented using a trial-and-error method based on the finite element method (FEM). The base model-design method that uses conventional magnetic equivalent circuits is quite inaccurate. To avoid such inaccuracy, this study proposes a method that accurately calculates the inductance values at a practical operating point considering the control issue. To achieve this objective, the flux linkage due to the current phase angles in each section is modeled using magnetic equivalent circuits. The result is used to calculate the inductance, assuming relative permeance waves. Finally, the validity of this study is verified by FEM simulation and testing.

Axis Current Control and Finite Element Method

Th\s paper proposes a novel plot called an NE-Map that has two axes representing the no-load electromotive force (EMF) and the number of windings per slot. The NE-Map is applied to the design of an interior permanent magnet synchronous motor. Here, the design of the rotor is implemented using a magnetic equivalent circuit. In addition, the phase currents and current phase angles are estimated by considering the maximum torque per ampere and the flux weakening control method, and a stator is designed using this estimation. As these processes are presented in terms of the values of the EMF and the number of windings per slot, this representation allows for the verification of the relationship among the motor parameters and the determination of the final model by reflecting the design constraints. This process is applied to the design of a traction motor in hybrid EVs, and its validity is verified by comparison with finite element analysis and test data.

Inductance Calculation in IPMSM Considering Magnetic Saturation

The following study carried out the characteristic analysis based on the magnet segment of Interior Permanent Magnet Synchronous Motor(IPMSM) for the urban railway vehicles. IPMSM affects the electromagnetic characteristics through the change in magnetic flux based on the rotor structure, and significantly influences the structural features through the change of pressure. Therefore, satisfied by the demanded traction force of the IPMSM, magnet segment derived three different model types. The 1-segment PM model consisted an undivided permanent magnet. The 2-Bridge model consisted a divided permanent magnet with the application of Bridge. The 3-Bridge model consisted additional dividing with one more Bridge applied. The electromagnetic characteristics of the three models were compared and analyzed along with the structural features regarding the scattering of permanent magnet based on strong centrifugal force from the rotation of the rotor at high speed. In conclusion, the final model with electromagnetic characteristics and structural features most suitable of IPMSM for the urban railway vehicles was derived, and the effectiveness was verified through the characteristic experiments after the production of the derived model.

NE-Map-Based Design of an IPMSM for Traction in an EV

The interior permanent-magnet synchronous motor (IPMSM) is often used as the traction motor of hybrid electric vehicles (HEVs) and electric vehicles (EVs) due to its high power density and wide speed range. This paper introduces the 120kW class IPMSM for the traction motor of military truck. This system as SHEV (series hybrid electric vehicle) needs a traction motor which generates high torque. To reduce the cost, the design approach which the reluctance torque would be maximized by varying the dq-axis inductance is introduced. If the model designed by design approach satisfies the desired torque, the magnetic torque can be reduced as much as reluctance torque increases, and consequently the amount of permanent magnets can be reduced. The reduction gear and high speed operation of motor are needed for the miniaturization of motor. Thus, a fairly large centrifugal force is generated due to the high speed operation of motor. This force causes the mechanical interference between the rotor and the stator, and the design approach which adds the iron bridge is explained to solve the interference. The initial model and improved model which reduce the cost and improve the mechanical durability are compared by FEA, and the models are produced. Finally, the FEM results were verified through an experiment.

A Study on the Characteristics Analysis According to the Permanent Magnet Segmentation Change to IPMSM for Urban Railway Vehicle

Unlike the existing bar-type permanent magnets, it is difficult to magnetize the ferrite spoke-type permanent magnet synchronous motor (PMSM), because the permanent magnet is placed deep inside the shaft. In order to magnetize permanent magnet, a high magnetic field intensity is required. However, the high magnetic field intensity may cause demagnetization of surrounding permanent magnets. It has a bad effect on the magnetization of the permanent magnet and the performance of the spoke-type PMSM. In this paper, we proposed magnetizer models for magnetization of spoke-type 10 pole rotor and the inter-pole winding to reduce the demagnetization of surrounding permanent magnets. Finally, the optimally designed model was manufactured and the performance of the magnetizer was verified.

Design to reduce the cost and to improve the mechanical durability of IPMSM for the traction motor of military truck

A method is presented to determine the detailed design of a 150 kW-class interior permanent-magnet synchronous motor. The basic designs of stator and rotor were determined, after dividing the designed models into the best and worst cases on the basis of the rotor-shaped parameters. First, the three-bridge basic model satisfying the structural (mechanical) safety factor of the rotor is proposed. The three-bridge basic model does not meet the required torque at rated and maximum speed compared to the no-bridge model. Therefore, it is necessary to perform the design analysis through the selection of various design parameters. However, it is hard and takes alot of time to perform an analysis with numerous shape parameters. Therefore, design parameters with the greatest effect on torque and induced voltage are found using the sensitivity analysis. And the 3-D voltage–inductance map parameters were analyzed. Then, the design of the final model was predicted. On the basis of this prediction, the final model was extracted with a trend analysis. Finally, the final model was validated with experiments.

Design of 3-Times Magnetizer and Rotor of Spoke-Type PMSM Considering Post-Assembly Magnetization

The high-capacity traction motor for railway vehicles calls for a high output density, which necessitates using a Neodymium magnet that has a high energy density. Also, any failure in the inverter may lead to high current. Due to the high Current, or the reverse magnetic field, the permanent magnet is subjected to demagnetization. Specifically, a new demagnetization curve called a recoil line is generated, resulting in permanent demagnetization. Thus, the demagnetization characteristics were analyzed in light of the recoil line. Based on a calculation scenario demagnetization was predicted via the back EMF, and the final model was derived. In addition, performance and temperature saturation tests were performed for verification.

Optimal Rotor Design of an 150 kW-Class IPMSM by the 3-D Voltage–Inductance-Map Analysis Method

In recent years, numerous studies have attempted to find and explore the auxiliary brake and the oil pressure type and electrical type are mainly used. However, the model proposed here is to self-excited eddy current brake. The advantage of this is it does not require an external power supply and can be produced to reduce the size than others. This self-eddy current brake consists of RLC circuit so resistance, inductance and capacitance value can be considered a fixed value. But, inductance and resistance value changes depending on the shape, temperature and magnetic alteration. Therefore, in this paper, the focal point is characteristic analysis according to the parameter variations. Also, using this result, this paper explains how to estimate the capacitance.In recent years, numerous studies have attempted to find and explore the auxiliary brake and the oil pressure type and electrical type are mainly used. However, the model proposed here is to self-excited eddy current brake. The advantage of this is it does not require an external power supply and can be produced to reduce the size than others. This self-eddy current brake consists of RLC circuit so resistance, inductance and capacitance value can be considered a fixed value. But, inductance and resistance value changes depending on the shape, temperature and magnetic alteration. Therefore, in this paper, the focal point is characteristic analysis according to the parameter variations. Also, using this result, this paper explains how to estimate the capacitance.