• The Transactions of the Korean Institute of Power Electronics
• /
• v.10 no.4
• /
• pp.388-396
• /
• 2005

SRM has not been put into practical applications widely because of its large torque ripple, acoustic noise and low power factor. In addition, a traditional position sensor is needed for the drive control. So we propose an improved sensorless drive method of Switched Reluctance Motors using impressed voltage pulses. Conventional impressed voltage pulse method has a problem of phase delay because of low-pass filter. So in this paper we propose an unproved sensorless driving method based on the impressed voltage pulse using new pulse-shift circuit technique that overcomes the phase delay and start-up problem. Proposed method is implemented in a simple analog circuit instead of using an expensive DSP.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.10 no.4
• /
• pp.323-330
• /
• 2005

In order to increase reliability and reduce system cost, this paper studies particularly applicable method for sensorless PM BLDCM drive system. The waveform of the motor internal voltages(or back emf) contains a fundamental and higher order frequency harmonics. Therefore the third harmonic component is extracted from the stator phase voltage. The resulting third harmonic signal keeps a constant phase relationship with the rotor flux for any motor speed and load condition, and is practically free of noise that can be introduced by the inverter switching, making this a robust sensing method. In addition, a simple starting method and a speed estimation approach are also proposed. Some experimental results are Provided to demonstrate the validity of the proposed control method.

• Journal of Power Electronics
• /
• v.17 no.3
• /
• pp.641-652
• /
• 2017

This paper proposes a cost-effective topology to drive a three-phase open-end load based on a five-leg indirect matrix converter (IMC) and a space vector modulation (SVM) method. By sharing an inverter leg with two load terminals, the proposed topology can reduce the number of power switches when compared to topologies based on a direct matrix converter or a six-leg IMC. The new SVM method uses only the active vectors that do not produce common-mode voltage (CMV), which results in zero CMV across the load phase and significantly reduces the peak value of the CMV at the load terminal. Furthermore, the proposed drive system can increase the voltage transfer ratio up to 1.5 and provide a superior performance in terms of an output line-to-line voltage with a three-level pulse-width modulation waveform. Simulation and experimental results are given to verify the effectiveness of the proposed topology and the new SVM method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.11a
• /
• pp.846-852
• /
• 2004

This paper proposes a method to calculate the characteristics of a coupled hydrodynamic journal and thrust bearing of a HDD spindle motor. The governing equations for the journal and thrust bearings are the two dimensional Reynolds equations in ${\theta}z$ and $r\theta$ planes, respectively. Finite element method is appropriately applied to analyze the coupled journal and thrust bearing by satisfying the continuity of mass and pressure at the interface between the journal and thrust bearings. The pressure in a coupled bearing is calculated by applying the Reynolds boundary condition and compared with that by using the Half-Sommerfeld boundary condition. The static characteristics are obtained by integrating the pressure along the fluid film. The flying height of spindle motor is measured to verify the proposed analytical result. This research shows that the proposed method can describe HDB in a HDD system more accurately and realistically than the separate analysis of a journal or thrust bearing.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.13 no.3
• /
• pp.171-178
• /
• 2008

Pressure control of hydraulic pump using SRM with pressure predictor and direct torque control method is presented in this paper. Nowadays, high efficiency and high performance motor drive is much interested in hydraulic pump system. But the hydraulic pump system has an inherent defect that its dynamic behavior causes by interaction between the sensor and hydraulic load. It will make low performance of whole system, even unstable and oscillatory. Proposed system integrates pressure predictor and direct instantaneous torque control (DITC). The pressure predictor includes Smith predictor, which is easy to improve unstable or long oscillation in traditional negative feedback control and popular PID control architectures. And DITC method can reduce inherent torque ripple of SRM, and develop smooth torque to load, which can increase stability and improve the torque response of SR drive. So high dynamic performance and stabilization can achieved proposed hydraulic system. At last, the proposed hydraulic system is verified by simulation and experimental results.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.5
• /
• pp.1945-1955
• /
• 2018

High frequency signal injection (HFI) is an alternative method for estimating rotor position of interior permanent magnet synchronous motor (IPMSM). The general method of frequency and amplitude selection is based on error tolerance and experiments, and is usually set with only one group of HF parameters, which is not efficient for different working modes. This paper proposes a novel rotor position estimation scheme by HFI with optimized frequency and amplitude, based on the mathematic model of IPMSM. The requirements for standstill and low-speed operational modes are met by applying this novel scheme. Additionally, the effects of the frequency and amplitude of the injected HF signal on the position estimation results under different operating conditions are analyzed. Furthermore, an optimization method for HF parameter selection is proposed to make the estimation process more efficient under different working conditions according to error tolerance. The effectiveness of the propose scheme is verified by the experiments on an IPMSM motor prototype.

• Proceedings of the KIPE Conference
• /
• 2000.07a
• /
• pp.709-712
• /
• 2000

In general three position sensors are needed to drive three phases SRM. Single position sensor driving method for three phases Switched Reluctance Motor(SRM) is proposed in this paper. By using single position sensor the cost of SRM is reduced. But position sensor the cost of SRM is reduced. But position detection at the staring is needed for single position sensor driving method. In this paper we propose the active align method to detect the relative position of rotor to three phases and align to the nearest phase. We proved the validity of the method by experiment and compare with other method.

• Proceedings of the KIPE Conference
• /
• 1998.07a
• /
• pp.193-196
• /
• 1998

A new excitation method of switched reluctance motor drive is described in this paper. This excitation method produces reluctance torque by mutual action between two phases as well as conventional self reluctance torque due to two phase excitation at a time. In other words, the change of self inductance and mutual inductance are used to produce torque. This paper suggests the operational principle, the mechanism of torque product of switched reluctance motor with two phase excitation. The acoustic noise characteristics of two phase excitation method are described against that of conventional excitation method.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.12 no.6
• /
• pp.643-656
• /
• 2019

The development of hot social networking services, including the Internet, has transformed rental car services into IT-based car-sharing services. The car-sharing service is a service that allows people to rent cars online without having to face-to-face. It has become the preffered service among young people who are accustomed to drinking and eating alone. Users can use their smartphones to book their types of cars and hours of rent, and then go to a nearby designated parking lot to use their reserved cars. You can open a designated car door with a smart phone and drive. It is a very convenient service to pay for the distance you drive. However, the car-sharing service already in use in business has the following problems: underage who do not have a driver's license may drive a car borrowed by an acquaintance, the status of a license registered at the time of join membership with a car-sharing company may change to a suspension or cancellation of a license while renting and driving, or even a drunk person may rent a car and drive. In this paper, the method to solve these problems has been studied and proposed. The proposed method is to reduce the cost of investment by a car-sharing service provider and to minimize user inconvenience. And, it was compared and analyzed with the existing method. For the method to be used efficiently, the active operation of the car-sharing company and the government's policies will have to be supported.

• Proceedings of the KIPE Conference
• /
• 2000.07a
• /
• pp.317-320
• /
• 2000

This paper proposes a voltage compensation method to improve the control performance of B4 inverter which is studied for low-cost drive systems. The B4 inverter employs only four switches and it has a center-tapped connection in the split dc-link capacitors to one phase of a three-phase motor. In the B4 topology unbalan-cd three-phase voltages will be generated by the dc link voltage ripple. To solve this problem we present a voltage compensation method which adjusts switching times considering dc link voltage ripple. The proposed method is verified by simulation results,