• Proceedings of the KIEE Conference
• /
• 2000.07e
• /
• pp.122-128
• /
• 2000

The SRM is a simple and robust machine which is finding applications over a wide power and speed range. To properly evaluate the motor performance, a reliable model design is required. This paper explains the various excitation mode and winding configuration to analyze the torque performance of SRM. A number of different idealized current excitation patterns are introduced, using unipolar, bipolar & square excitation, and the output torques produced by the various winding configurations are compared. The electromagnetic torque of the SRM was calculated from the rate of change of co-energy with respect to angular displacement. The simulation result shows that 3-phase square excitation mode models have revealed higher torque performance.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.49 no.9
• /
• pp.565-571
• /
• 2000

SRM has been applied to many commercial applications that require economical advantages and high performance abilities. But it has some drawbacks such as acoustic noise due to the abrupt change of mmf level when commutation. The abrupt change of a phase excitation produces mechanical stresses and it results in torque ripple and noise. This paper deals with an analysis of vibration and noise in SRM drive. Several types of excitation method are taken into account. The 1-phase and 2-phase excitation technique of short-pitch winding 2-phase excitation technique of full-pitch winding are tested. The acoustic noise is reduced remarkably through the sequential phase excitation in the 2-phase excitation. It is because that the scheme reduces abrupt change of excitation level by distributed balanced excitation with free-wheeling during commutation.

• Journal of Industrial Technology
• /
• v.18
• /
• pp.329-334
• /
• 1998

The purpose of this study is to design and manufacture a vibration exciter, which can be used in the education and research for the vibration engineering. For this purpose, a direct drive type vibration exciter is developed, which consists of a motor, an inverter, eccentric rotating sleeves and two excitation plates. Developed exciter is tested on some dynamic characteristics to evaluate its excitation performance. Test results show that the developed machine can excite bodies on the horisontal vibrating plates in x,y direction by the constant displacement amplitude in the frequency range below 50Hz, which confirm that the exciter can be used as a vibration testing machine in the low frequency range.

• Proceedings of the KIPE Conference
• /
• 2001.07a
• /
• pp.1-4
• /
• 2001

SRM(Switched Reluctance Motor) uses reluctance torque by pulse excitation control. SRM drives are much studied in electrical vehicles and industrial application due to the simple, robust mechanical structure and high speed characteristics. For the high performance control of SRM, it is necessary to synchronize the stator phase excitation with the rotor position. This paper proposes a new encoder for high performance excitation control of SRM. The proposed encoder has complex structures of incremental and absolute encoder. An each phase inductance profile can be synchronized with 4-bit absolute position signal and incremental pulses are used for speed detection. Low cost and simple manufacturing of SRM encoder is possible.

• Journal of Power Electronics
• /
• v.5 no.3
• /
• pp.218-223
• /
• 2005

A simple construction, low cost, and a fault tolerant power electronic drive have made the switched reluctance drive a strong contender for many applications. But the switched reluctance drive exhibits higher levels of vibration and acoustic noise than most competing drives. The main source of vibration in the switched reluctance drive is generated by the rapid change of radial magnetic force when the phase current is extinguished during commutation. In this paper, some excitation methods are proposed to reduce the vibration and acoustic noise of the switched reluctance drive. The excitation strategies considered in this research are 1-phase, 2-phase and hybrid excitation methods. The 1-phase method is the conventional approach, while in the 2-phase method, the two phases are excited simultaneously. The hybrid excitation has 2-phase excitation using a long dwell angle as well as conventional 1-phase excitation. The vibration and acoustic noise are compared and tested. The suggested 2-phase and hybrid strategies reduce acoustic noise because the schemes reduce the abrupt change in excitation level by using distributed and balanced excitation.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
• /
• v.2B no.3
• /
• pp.109-114
• /
• 2002

This paper analysis the transient performance of the modified excitation system using 4-quadrant chopper for a synchronous machine connected to HVDC system. Conventionally, capacitors are used to supply reactive power requirement at a strong converter bus. And the installation of a synchronous machine is essential in an isolated weak network to re-start after a shutdown of HVDC and to increase the system strength. However, a conventional static excitation system has some problems which are harmonic instability and the system stress due to overvoltage. To reduce these problems, the new excitation system, which has 4-quadrant chopper, is proposed. As the proposed system provides the capability to allow reverse current and isolate between AC network and excitation power, problems of overvoltage and harmonic instability can be solved. The investigation is performed and confirmed by the time domain digital simulation using PSCAD/EMTDC program.

• Proceedings of the KIEE Conference
• /
• 1997.07b
• /
• pp.660-662
• /
• 1997

A new improved excitation control system for power plant synchronous generators has been developed by KEPRI (Korea Electric Power Research Institute). The reliability of the excitation system is increased by designing a dual channel automatic voltage regulator(AVR). Also the performance of the excitation system is improved by Self-Tuning adaptive Controller. A software package is developed for the excitation control system, and a field test is conducted to verify the system performance.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.51 no.2
• /
• pp.69-75
• /
• 2002

AVR parameter tuning for voltage control of power system generators has generally been performed with the analytic methods and the simulation methods, which mostly depend on off-line linear mathematical models of excitation control system. However, due to the nonlinear nature of excitation control system, excitation control system performance of the tuned Parameters using the above conventional tuning methods may not be appropriate for some operating conditions. This paper presents an AVR parameter tuning method using actual on-line data of the excitation control system with the parameter optimization technique. As this method utilizes on-line operating data of the target excitation control system not the mathematical model of the system, it can overcome the limitation of model uncertainty Problems in conventional method, and it can tune the AVR parameter set which gives desired performance at the operating conditions. For the verification of proposed tuning method, two case studies with scaled excitation systems and the real-time power system simulator are presented.

• Proceedings of the KIEE Conference
• /
• 2000.07b
• /
• pp.955-957
• /
• 2000

This paper has explained a various excitation mode to analyze the torque performance of SRM. The simulation results show that 3-phase square excitation mode models have revealed high torque performance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2012.10a
• /
• pp.437-444
• /
• 2012

In this paper, the measurement method of the decoupling performance of a underwater decoupling material is studied. First, the simple vibro-acoustic coupled model of a multi-layered underwater decoupling material attached to a plate is analytically derived using impedance transfer matrix. Two test methods are introduced using the theoretical expression of the simple model. One is based on the ratio of the plate vibration and the radiated pressure under impact excitation of the plate. The other is based on the reciprocity theorem and uses the ratio of the incident pressure and the plate vibration under projector excitation in water. Some measurements are carried out according to the test methods using a pulse tube. The test results show the advantages and disadvantages of two methods. It is also shown that the combination of impact and projector excitation methods may be a useful tool to evaluate the performance of a underwater decoupling material.