• 제어로봇시스템학회논문지
• /
• 제5권7호
• /
• pp.862-867
• /
• 1999

In general, the realization of high performance brushless permanent magnet motors which are widely used in servo drive is focused on the linear control for ripple-free torque. This is also the main problem that should be solved in all AC motors including induction motor to achieve high performance control, and recent papers deal with this problem. In this paper, the novel optimal excitation scheme of brushless permanent magnet motor producing loss-minimized ripple-free torque based on the d-q-0 reference frame is presented including 3 phase unbalanced condition. The optimized phase current waveforms that are obtained by the proposed method can be a reference values and the motor winding currents are forced to track it by delta modulation technique. As a results, it can be shown that the proposed work can minimize the torque ripple by the optimal excitation current for brushless permanent magnet motor with any arbitrary phase back EMF waveform. Simulation and experimental results prove the validity and practical applications of the proposed control scheme.

• 한국전기전자재료학회논문지
• /
• 제20권5호
• /
• pp.425-429
• /
• 2007

A linear ultrasonic motor was designed by a combination of the longitudinal and bending mode. linear ultrasonic motors are based on an elliptical motion on the surface of elastic body, such as bar or plates. The corresponding eigen-mode of one resonance frequency can be excited twice at the same time with a phase shift of 90 degrees in space and time. That is excite symmetric and anti-symmetric modes. Then it determines the thrust and speed of the motor. Linear ultrasonic motors are investigated experimentally in according to be fabricated a general classification to motor structure and material characteristic. There was the first to simulate as use of finite element analysis ANSYS 9.0. The AL-T2W8-ARM14-LEG18-ANGLE80 motor has a maxim efficiency 18 % under the speed 0.14 m/s, thrust 345 gf and preload 280 gf, operating frequency is 57.6 kHz.

• International Journal of Precision Engineering and Manufacturing
• /
• 제8권3호
• /
• pp.45-49
• /
• 2007

A gearing system emits inconsistent noises from the impact of gear teeth when defects are present, but it is not easy for a noise inspector on a production line to distinguish defective products objectively. Since customers constantly complain about various noises from geared motors, it is desirable to devise an analytical technique to classify motors. However, it is difficult to separate inconsistent noises due to defective gears from the overall noise produced by a geared motor using a general signal processing method such as a FFT because low frequency impulse signals have a tendency not to appear in the frequency domain. In this paper, we propose a method that can be used to obtain more objective estimates and measurements of inconsistent noises from a gearing system. The proposed method makes use of the cepstrum domain with an applied autocorrelation and comb lifter, followed by a domain inversion.

• 한국조명전기설비학회지:조명전기설비
• /
• 제9권5호
• /
• pp.41-50
• /
• 1995

Single-phase induction motors are widely used in many light duty applications, especially in home and office. many applications which use these motors require adjustable speed control continuously. In general, the speed control of single-phase induction motor is accomplished at a few discrete speeds by using tapped-windings, pole switching or gear. These techniques are inefficient and complicated. In this paper, Torque controller which adjusts a generating torque using phase difference between main winding voltage and auxiliary winding voltage is proposed. The analysis includes the determination of the relationship between the auxiliary winding voltage is proposed. The analysis includes the determination of the relationship between the auxiliary winding voltage phase angle and torque. Simulation results of the torque-speed characteristics using the controlled auxiliary winding supply are shown and discussed. and the drive is tested experimentally to verify the results of the theory by using a dynamometer.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 학술대회 논문집 전문대학교육위원
• /
• pp.95-99
• /
• 2001

In this paper, a drive system for multi-phase bipolar brushless DC (MPB BLDC) motor is presented. This drive system is used for an electric bicycle. In general, the maximum and minimum speed of electric bicycle are required by law. At first, the proposed controller is satisfied for the limited speed control. Secondly, the system has a technique of exited with modulation(EWM), bidirection control, and partial square wave control. Thirdly, the controller is designed for system stability Experimental results show the performance of the proposed controller of MPB BLDC motors for an electric bicycle.

• 대한전기학회논문지
• /
• 제38권3호
• /
• pp.173-181
• /
• 1989

A split-phase induction motor with asymmetrical magnetizing reactance axes develops starting torque and its efficiency can be high under certain conditions. In this paper, one method of producing the asymmetry of magnetizing reactance axes is described. The grain-oriented silicon steel core is used to produce the asymmetric axes instead of non-oriented silicon steel core which is used in general motors. The optimum design method for the motor is suggested and analyzed. To verify this suggestion, the permanent capacitor run type induction motors are designed to be driven at balanced condition by its asymmetrical effect, and then the oscillating torque due to the asymmetry of motor structures are analyzed. Tests of the sample motor have shown good performance comparable to ordinary types. This motor structure can be used where high effciency and reliability are required, and also the amount of core materials can be reduced due to its high permeability.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
• /
• pp.70-72
• /
• 1998

Because of using PWM inverters and converters. The problems of insulation breakdown is emerging in both high voltage motors and general motors. In conventional methods, the viewpoint of surge problems is wave propagation with or without cable and inverter. For the purpose of knowing the situation of insulation breakdown, the end-turn coil of windings in the motor winding insulation structure is modelled by FEM, and field analysis of that is done. For first step, only end-turn coil is modelled and the model is simulated with FEM by approximating the resistivity of metallic foil surrounding insulation layers with having nonlinear property. Next, the result of simulation with nonlinear resistivity are compared with the result of linear resistivity. Because of microscope analysis, there is the problem of generalization but the situation of corona discharge in end-turn coil will be explained from this simulation.

• Corrosion Science and Technology
• /
• 제18권4호
• /
• pp.117-120
• /
• 2019

Considering the tendency of development of electrification vehicles, development and verification of new evaluation technology is needed because of new technology applications. Recently, as the battery package is set outdoors of an electric vehicle, such vehicles are exposed to corrosive environments. Among major components connected to the battery package, rust prevention of high-voltage cables and connectors is considered the most important issue. For example, if corrosion of high voltage cable connectors occurs, the corrosion durability assessment of using an electric vehicle will be different from general environmental corrosion phenomena. The purpose of this study is to investigate the corrosion mechanism of high voltage cable connectors of an electric vehicle under various driving environments (road surface vibration, corrosion environment, current conduction by stray current, etc.) and develop an optimal rust prevention solution. To improve our parts test method, we have proposed a realistic test method to reproduce actual electric vehicle corrosion issues based on the principle test.

• 융합신호처리학회논문지
• /
• 제10권1호
• /
• pp.86-92
• /
• 2009

유도 전동기의 사용이 증가함에 따라 유도전동기의 고장은 산업 사회에 커다란 피해를 끼치게 되었다. 그렇기 때문에 유도 전동기의 고장을 찾아내는 것은 매우 중요한 문제로 부각되었다. 하지만 그 중에서도 문제점은 유도전동기의 고장은 종종 오랜 시간에 걸쳐 진행된다는 것이다. 그것은 빠른 진단이 매우 중요하다는 것을 뜻한다. 이에 대해 많은 연구가 진행되어 왔으며 가장 일반적으로 쓰이는 고장 진단 방법은 진동 센서를 이용한 전동기의 기계적 고장을 찾는 방법이다. 하지만 이 방법은 신뢰도가 높은 검증 방법임에도 불구하고 높은 시스템 가격과 활용의 어려움으로 인해 새로운 방법들이 시도가 되었다. 이 논문은 시스템을 기반으로 웨이블릿 변환을 이용한 유도전동기의 고장 진단 기술을 구현하는 것을 보여주며 윈도우즈 기반 C++을 이용하여 고장인지 아닌지를 결정하는 알고리즘으로 구성되어 있다. 전체 시스템은 전류 데이터 수집 보드와 PC를 이용한 신경망 알고리즘으로 실시간으로 수행 될 것이다.

• 한국자동차공학회논문집
• /
• 제19권3호
• /
• pp.57-64
• /
• 2011

In general, the durability performance of a large-sized military truck has been checked through a field durability test which required many man-hours and costs. To reduce these expenses, the durability analysis using a VTL(Virtual Test Lab) at an initial design stage was introduced recently. In this paper, the VTL with a multi-post testrig template for a large-sized truck was developed to compute the load histories transferred to cabin and chassis frame. The VTL consisted of trimmed FE models of cabin, chassis frame, and deck, dynamic models of front and rear suspensions, and a 8-post testrig template. The basic characteristics of the VTL were correlated with experimental results which had been extracted from actual driving test, modal test, and static weight test. The fatigue analysis using MSM(Modal Superposition Method) was applied to evaluate the durability performance of a large-sized military truck. From a series of analytic methods, it is shown that the fatigue analysis process using the VTL could be a useful tool to estimate the fatigue lives and weak areas of a large-sized military truck.