• 전기학회논문지
• /
• 제59권3호
• /
• pp.575-580
• /
• 2010

This paper is to design an optimum power conversion device for the system required for development of a low cost 3-phase power inverter. For this purpose, in order to meet with endurance required by the industry, failure mode is standardized to guarantee lifetime of a power semiconductor by monitoring real time power loss and to facilitate failure mode analysis. As normality of heat loss of a power semiconductor is identified remaining in a certain range by comparing heat rise slope between that is calculated by using average current or average loss and that is measured at a heat sink, its feasibility is confirmed by experiment.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2000년도 전력전자학술대회 논문집
• /
• pp.90-94
• /
• 2000

A conventional power supply to drive a microwave oven has ferro-resonant transformer and high voltage capacitor(HVC). Though it is simple transformer is bulky heavy and has low-efficiency. To improve this defect a high frequency switching inverter-type power supply has been investigated an developed. in recent years. But because of it's additional circuit and devices inverter-type power supply is more expensive than conventional one. In this paper The design procedure of a novel HVC embedded high frequency transformer is proposed for down-sizing and cost reduction. Also transformer equivalent circuit model is derived by FEM analysis and parameter measurements. And the operation of proposed HVC embedded transformer is verified by simulation and experimental results.

• 동력기계공학회지
• /
• 제16권6호
• /
• pp.73-78
• /
• 2012

This paper investigates the restart performance of sensorlessly controlled IPMSM Fan motor free-running in middle or high speed range just after inverter power off. There could be some difficulties to extract exact position information by using conventional sensorless control for restarting the motor because of stopped inverter operation. To solve this problem, we proposes to use low cost hall sensor. Using a hall sensor with SMO (Sliding Mode Observer) give us a solution to facilitate rotor position information extraction. The algorithm in this paper shows a certain way of the restarting method.

• 전력전자학회논문지
• /
• 제20권1호
• /
• pp.38-44
• /
• 2015

This paper presents the sensorless drive method for mono inverter dual parallel (MIDP) surface mounted permanent magnet synchronous motor (SPMSM) drive system. MIDP motor drive system is a technique that can reduce the cost of the multi motor driving system. To maximize this merit of the MIDP motor drive system, the sensorless technique is essential to eliminate the position sensors. This paper adopts an appropriate sensorless method for MIDP SPMSM drive system, which uses the reduced order observer and phase locked loop (PLL) to reduce the calculation burden. The I-F control method is implemented for start-up and low speed operation. The validity and performance of the proposed algorithm are shown via experiments with 600-W SPMSMs.

• 전력전자학회논문지
• /
• 제18권2호
• /
• pp.145-152
• /
• 2013

Electrolytic capacitors used for smoothing DC link voltage is one of the major root causes of fault in power electronic system. The aging of aluminum electrolytic capacitors is expressed by the increase of their equivalent series resistance (ESR) and the reduction of their capacitance. Thus, the proposed technique in this paper is to measure capacitance, by comparing energy loss of DC link capacitors with stator resistor in electric machine. Condition of DC link capacitors can be estimated from the capacitance decrease rate between initial and aged capacitors. The results show that the proposed technique provides an easy, widely applicable and simple low cost solution for detecting dc link capacitor degradation.

• 동력기계공학회지
• /
• 제3권2호
• /
• pp.70-78
• /
• 1999

The vector controlled induction motor(I.M) with speed sensor has been widely used for variable speed drive systems. In these application fileds, speed sensorless control are expected strongly to progress reliability, simplicity and cost performance of I.M and to expand its application part. This paper describes a novel speed sensorless control method of I.M based on feedforward quick torque response control technique. Especially, this paper aimed at the realization of sensorless control in the very low speed region, The proposed method can be formulated simply from a motor circuit equation and conducted easily by detecting primary motor currents and a voltage command at every sampling time. Throughout some results of numerical simulations with the assumption of using a pulse width modulation(PWM) voltage source inverter, the validity of the method was successfully confirmed.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2006년도 전력전자학술대회 논문집
• /
• pp.81-83
• /
• 2006

The conventional cold cathode fluorescent lamp (CCFL) driver for LCD TV has a transformer for each lamp to step up the high sinusoidal waveform from the low input voltage. The transformer used in the conventional topology causes the driver to have bulky size and high cost. This paper proposes a new transformer-less CCFL driver for LCD backlight that is based on the parallel-loaded resonant inverter topology. This resonant topology enables the circuit to supply enough high voltage for CCFL without a transformer. Also, with current-balancing technique, this transformer-less inverter drives 16 CCFL lamps.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2002년도 전력전자학술대회 논문집
• /
• pp.45-48
• /
• 2002

This paper proposes a grid-connected inverter using the negative conductance of PV power system, which has four IGBTs and simple controller. Most of modern electric loads generate the current harmonics and the line voltage distortion. The new solar-to-ac converter(STAC) provides by emulating a negative conductance load to the line voltage, so the current harmonics from STAC is canceled the effect of the harmonics from other loads. As a result, the line voltage distortion is decreased. The proposed system have low cost, small size, and light weight compared to conventional photovoltaic converter

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
• /
• pp.352-356
• /
• 1998

This paper describes minimum current control method for size reduction and performances improvement at unified inverter-induction motor system. This control method is based on V/F without speed sensor. Through the use of minimum stator current points at required torque during V/F operation it is possible to minimize the size of heat-sink related with the losses of power circuit and to improve overall efficiency compared to conventional V/F control. Using this proposed scheme, it is so much more useful to apply to some fields such a selectric vehicles. air conditioning system and textile mills where the limited space is given and required low cost.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제48권4호
• /
• pp.219-225
• /
• 1999

This paper proposes a new reactive-power compensator composed of a thyristor current-source inverter. The compensator consists of a 6-pulse thyristor bridge, dc reactor, and a commutation circuit. The commutation circuit offers the thyristor bridge to have PWM operation with minimal switching losses. The operation of proposed system was analyzed by computer simulations with EMTP and experimental works with hardware scaled-model. The proposed system would have low cost and easy expansion of operation voltage due to using the conventional thyristors.