• 전자공학회논문지A
• /
• 제32A권9호
• /
• pp.1202-1208
• /
• 1995

Inter-processor communication is required to manage resources in ATM switching system where processors are distributed. ATM switching system, which was developed in our institute, does't have dedicated communication path for inter-processor communication, but use the ordinary switching network same as user data. Therefore, we should test communication paths and equipments before running various application software programs. In this paper, we propose a method to test communication paths between processors in ATM switching system and describe an implemented program using this method.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2001년도 하계종합학술대회 논문집(5)
• /
• pp.249-252
• /
• 2001

A large number of soft switching topologies included a resonant circuit have been proposed. But these circuits increase number of switch in circuit and complicate sequence of switching operation. In this Paper, the authors propose power conversion system, DC-AC inverter of high efficiency and high power factor with soft switching mode by partial resonant method. The result is that the switching loss is very low and the efficiency of system is high. And the snubber condenser used in partial resonant circuit makes charging energy regenerated at input power source for resonant operation.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.106-109
• /
• 2008

Piecewise linear diode models are widely used for large-signal circuit analyses, especially power electronic circuit simulations. When using a piecewise linear diode model for simulation, a switching method to select a proper one among linear models is needed. The conventional switching method keeps the previous ON, OFF state information, and applies different switching conditions according to the state. However, this method has difficulties especially in extending to multi-piecewise linear models. This paper presents a switching method which appropriately divides the v-i plane into regions and select a linear model according to the region where the operating point(the voltage and the current of the diode) belongs. This switching method is easily extended to multi-Piecewise linear models. An example using the tableau analysis and the backward Euler integration is presented for verification.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1996년도 하계학술대회 논문집 A
• /
• pp.616-618
• /
• 1996

This paper presents an unipolar PWM which commutated switching device only in a half period. This method reduced switching loss significantly because of decreasing switching number in n period. In high speed motor drive needed high frequency above 300 Hz fundamental frequency, this method is suited very well. This paper described the principle of unipolar PWM method, analyzed harmonic spectrum and compared with bipolar PWM, Modified PWM and Overmodulation method in switching loss.

• Journal of Power Electronics
• /
• 제18권2호
• /
• pp.604-614
• /
• 2018

This paper proposes a synchronous switching technique for a Vienna rectifier that uses carrier-based pulse width modulation (CB-PWM). A three-phase Vienna rectifier, similar to a three-level T-type converter with three back-to-back switches, is used as a PWM rectifier. Conventional CB-PWM requires six independent gate signals to operate back-to-back switches. When internal switches are operated synchronously, only three independent gate signals are required, which simplifies the construction of gate driver circuits. However, with this method, total harmonic distortion of the input current is higher than that with conventional CB-PWM switching. A reactive current injection technique is proposed to improve current distortion. The performance of the proposed synchronous switching method and the effectiveness of the reactive current injection technique are verified using simulations and experiments performed with a set of Vienna rectifiers rated at 5 kW.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
• /
• pp.735-737
• /
• 2004

This paper proposes a method of fault diagnostics on switching mode power supply. When the error of switching mode power supply cannot be found when the conventional diagnostics is performed, this proposed method first performs diagnosis on the switching mode power supply strictly to judge the operating condition. This method analyzes the PWM wave which depends on the load change, to make sure the feedback control of the power supply to diagnosis the operation of the power supply system.

• 전력전자학회논문지
• /
• 제22권2호
• /
• pp.150-158
• /
• 2017

This study proposes a new pulse-width modulation switching pattern for the low conduction loss of a three-level neutral point clamped (NPC)-based dual-active bridge (DAB) converter. The operational principle for a bidirectional power conversion is a phase-shift modulation. The conventional switching method of the three-level NPC-based DAB converter shows a symmetric switching pattern. This method has a disadvantage of high root-mean-square (RMS) value of the coupling inductor current, which leads to high conduction loss. The proposed switching method shows an asymmetrical pattern, which can reduce the RMS value of the inductor current with lower conduction loss than that of the conventional method. The performance of the proposed asymmetrical switching method is theoretically analyzed and practically verified using simulation and experiment.

• 한국지열·수열에너지학회논문집
• /
• 제8권2호
• /
• pp.9-15
• /
• 2012

The objective of this study is to investigate the influence on the heating performance for a water-to-water 10RT ground source heat pump by using the water switching and refrigerant switching method. The test of water-to-water ground source heat pump was measured by varying the compressor speed, load side inlet temperature, and ground heat source side temperature. The heating capacity and COP of the heat pump increased with increasing ground heat source temperature. As a result, compared to a refrigerant switching method, the water switching method with counter flow improves the heating capacity and COP by approximately 5% in average, respectively.

• 설비공학논문집
• /
• 제24권8호
• /
• pp.605-611
• /
• 2012

The objective of this study is to investigate the influence of the cooling performance for a water-to-water 10 RT ground source heat pump by using the water switching and refrigerant switching method. The test of water-to-water ground source heat pump was measured by varying the compressor speed, load side inlet temperature, and ground heat source side temperature. The cooling capacity and refrigerant mass flow rate of the heat pump increased with increasing ground heat source temperature. But COP of the heat pump decreased with increasing ground heat source temperature. As a result, the water switching method with counter flow, compared to a refrigerant switching method, improves the cooling capacity and COP by approximately 6~9% in average, respectively.

• Journal of Power Electronics
• /
• 제17권4호
• /
• pp.1097-1108
• /
• 2017

Accurate calculation of the conduction and switching losses of a power electronic converter is required to achieve the efficiency of the converter. Such calculation is also useful for computing the junction temperature of the switches. A few models have been developed in the articles for calculating the switching energy losses during switching transitions for the given values of switched voltage and switched current. In this study, these models are comprehensively reviewed and investigated for the first time for ease of comparison among them. These models are used for calculating the average amount of switching power losses. However, some points and details should be considered in utilizing these models when switched current or switched voltage presents time-variant and alternative quantity. Therefore, an applicable technique is proposed in details to use these models under the above-mentioned conditions. A proper switching loss model and the presented technique are used to establish a new and fast method for obtaining the average switching power losses in any type of power electronic converters. The accuracy of the proposed method is evaluated by comprehensive simulation studies and experimental results.