Tae-Uk Jung

Design Process of Interior PM Synchronous Motor for 42-V Electric Air-Conditioner System in Hybrid Electric Vehicle

This paper presents a design approach to an interior permanent magnetic synchronous motor (IPMSM) for the compressor of a hybrid electric vehicle operated in a 42-V battery system. The approach is to estimate the range of inductance and back-EMF to satisfy the required efficiency of IPMSM. Then, the preliminary geometry satisfying the region is decided by PM type, current density, fill factor, and so on. Last, the detailed design with optimization is performed to consider magnetic saturation and reduce cogging torque and torque ripple. At this time, the simulation results are obtained by finite element analysis and in consideration of operating temperature. In the end, the validity of the design process presented in this paper is verified by test.

Permanent magnet structure design of outer rotor radial flux permanent magnet generator for reduction cogging torque with design of experiment

Radial flux permanent magnet generator have higher output voltage and torque capability than axial flux permanent magnet generator. The efficiency is also higher than axial flux permanent magnet due to the lack of rotor windings have high power density and torque per current ratio, but the large cogging torque can be generated. Cogging torque would be the source of acoustic noise and vibration. It reduce very important for initial activation of wind turbine. In this paper, we are designed of outer rotor radial flux permanent magnet generator which is integrated within blade and then the pole arc ratio and magnet structure was designed in order to reduce the cogging toque.

Rotor Design to Improve Starting Performance of the Line-start Synchronous Reluctance Motor

A single-phase line-start synchronous reluctance motor (LSSynRM) has merits of low cost, high efficiency and reliability. LSSynRM has an unbalanced magnetic circuit caused by flux barriers and various shapes of conductor bars when starting. Thus the motor may generate unstable starting torque in accordance with the initial starting position of the rotor. This paper presents the rotor design to improve starting performance of the LSSynRM. Design variables are the number and the shape of the conductor bars. This design result is compared with the initial prototype and single-phase induction motor.

A Design Optimization of Asymmetric Air-gap Structure for Small 3-phase Permanent Magnet SPM BLDC Motor

As many researchers are relentlessly trying to improve the power generation schemes from the power grid, to meet the constantly increasing electricity demand. In this paper, the results of a finite element analysis are carried out to study on a design optimization of an asymmetric air-gap structure in 3-phase Permanent Magnet Brushless DC Motors. To achieve a high efficiency for a 3-phase PM BLDC motor, the asymmetric air-gap structure is proposed considering the rotation direction of a motor. Generally, a single-phase BLDC motor is applied asymmetric air-gap structure for starting. This is because the asymmetric air-gap structure causes reluctance variation so the motor can utilize reluctance torque toward a rotation direction. In this paper, the asymmetric air-gap is applied to 3-phase BLDC SPM motor so it utilizes reluctance torque with alignment torque. A proposed model is designed by 2-D FE analysis and the results are verified by experimental test.

Detection of shorted-turns in the rotor winding of cylindrical synchronous generators using discrete wavelet transform

This paper describes a method for detecting the shorted-turn of the rotor windings based on the discrete wavelet transform in the cylindrical synchronous generator. Multi-resolution analysis based on discrete wavelet transform provides a set of decomposed signals in independent frequency bands, which contain the independent dynamic information due to the orthogonality of wavelet function. In the proposed method, detecting the shorted-turn of the rotor windings is based on the decomposition of the rotor currents, where wavelet coefficients of these signals have been extracted. Comparing these extracted coefficients is used for diagnosing the healthy condition from faulty conditions. Experimental results show the effectiveness of the proposed method for detecting the shorted-turn of rotor windings in the cylindrical synchronous generator.

The Development of Hybrid Electric Compressor Motor Drive System for HEV

The HEV (Hybrid Electrical Vehicle) becomes commercialized recently because of high fuel efficiency and low air pollution. The highest output power system except the traction motor is an air conditioner compressor in HEV system. The full or hybrid electric compressor is applied for HEV. The general HEC (Hybrid Electric Compressor) requires the half power motor and drive system of the full electric compressor because the rated output power of motor drive system is designed to charge the minimum cooling capacity at the time of idle stop. Therefore, this hybrid electric is more economical and practical solution. In this paper, we studied about the motor drive system of hybrid electric compressor for HEV. The applied voltage specification is 42 V, an IPMSM (Interior Permanent Magnet Synchronous Motor) is designed and applied as the compressor drive motor.

Irreversible Demagnetization Fault Diagnosis of Permanent Magnet Synchronous Motor for Electric Vehicle

Recently, researchers have an interest on the electric vehicle because it is more eco-friendly and efficient than gas vehicle. Instead of a gas engine, the electric vehicle has a motor for propulsion. The permanent magnet synchronous motor which has permanent magnet instead of field winding in the rotor has especially higher efficiency and torque per weight than other types of motor. When the irreversible demagnetization is occurred, users can be expose to high risk of accident by the fault operation of motor. Because of this, the irreversible demagnetization of permanent magnet should be detected by using any kinds of method to reduce the risk of accident. In this study, the demagnetization diagnosis method based on the result of locked rotor test is proposed. Base on short measurement time, the proposed diagnosis method aims to detect the demagnetization fault when the electric vehicle is at a complete standstill. The proposed method is verified by using the finite element analysis.

New active clamp technique for switching losses reduction of MIC systems

Recently, the MIC system have been actively studied to reduce switching losses and improve its reliability and efficiency. The Active clamp Flyback converter is based on the Flyback converter topology. But, the Flyback converter generates the voltage spike between Drain and Source of the MOSFET device. This spike causes losses and noises of the converter. So, the Active clamp Flyback converter is studied the focus of the voltage spike reduction. In this paper, The New Active Clamp Fly-back Converter is proposed to improve the efficiency by the Power-Sim simulator and the experiment.

A Design on Reduction Cogging Torque of Dual Generator Radial Flux Permanent Magnet Generator for Small Wind Turbine

In this paper, the design for an electromagnetic structure and reduction cogging torque of a dual generator structured RFPM generator, which is a combination of the inner- and outer-rotor types, has been proposed. We call this a dual generator radial flux permanent magnet generator. To reduce the cogging torque, firstly, stator tooth pairing was designed; secondly, stator displacement was designed and finally, stator tooth pairing and stator displacement were carried out simultaneously. We found the optimal design condition about stator tooth pairing angle combination and stator displacement angle for cogging torque minimization. As a result, a cogging was reduced by 93.3[%] by this study.

Design comparisons of BLDC motors for electric water pump

Recently, many hydraulic automotive parts are being replaced by the electric parts using electric motor drive system because of high performance for the conventional car having engine and the growth of electric vehicles. In the many kinds of electrical motor drive systems, BLDC is generally applied for the power train motor, electric HVAC compressor, cooling fan and pump. It is due to high efficiency and high output power characteristics. In the BLDC motor design, the rare-earth magnet material e.g. Nd-Fe-B magnet is often used because of high flux density compared with any other magnet material. However, the material cost of Nd-Fe-B magnet is abnormally rising because of the shortage of supply. In this paper, the low cost design by the magnet material change is studied about the 20[W] BLDC motor design for electric water pump. The design results of conventional IPM (Interior Permanent Magnet) type BLDC motor using Nd-Fe-B magnet and SPM (Surface Permanent Magnet) type BLDC motor using Ferrite magnet is compared each other. As a result of this study, the design comparison results concerning about output performance and material cost are represented.