• 전력전자학회논문지
• /
• 제25권6호
• /
• pp.477-483
• /
• 2020

This study proposes a DQ synchronous reference frame model of a series-parallel tuned inductive power transfer (SP-IPT) system. The wireless power transmission system experiences control difficulty because the transmitter-side controller cannot directly measure the receiver-side load voltages and currents. Therefore, a control-oriented circuit model that shows the dynamics of the IPT system is required to achieve a well-behaved controller. In this study, an equivalent circuit model of the SP-IPT system in a synchronously rotating reference frame is proposed using the single-phase DQ transformation technique. The proposed circuit model is helpful in modeling the dynamics of the voltages and currents of the transmitter- and receiver-side resonant tanks and loads. The proposed circuit model is evaluated using frequency- and time-domain simulation results.

• 조명전기설비학회논문지
• /
• 제14권6호
• /
• pp.12-17
• /
• 2000

IN induction heating system the high frequency operation allows a rapid response to current fluctuation in the inverter and result in improved welding quality. To work induction heating of nonferrous metals, a welding power supply is need high working frequency and high power. This paper is shown design technique for increasing working frequency in induction heating for welding coppers. A series-parallel resonate inverter consists of H-type bridges, each of whose arms is composed of a combination of two parallel IGBTs. Inverter operating with the fixed frequency is controlled by pulse width modulation (PWM). As switching adapted the Zero-Voltage Switching technique to reduce switching losses the system is high efficiency. The propose inverter has feature which is high efficiency for very wide load variations with a narrow range of duty cycle ratio control and load short circuit capability. Detailed experimental results obtained from a 48[V] output, 500[W] experimental inverter are presented to verify the concept.

• 전기학회논문지
• /
• 제56권1호
• /
• pp.88-99
• /
• 2007

In this paper, a novel new pulse power generator based on IGBT stacks is proposed for pulse power application. Because it can generate up to 60kV pulse output voltage without any step- up transformer or pulse forming network, it has advantages of fast rising time, easiness of pulse width variation and rectangular pulse shape. Proposed scheme consists of series connected 9 power stages to generate maximum 60kV output pulse and one series resonant power inverter to charge DC capacitor voltage. Each power stages are configured as 8 series connected power cells and each power cell generates up to 850VDC pulse. Finally pulse output voltage is applied using total 72 series connected IGBTs. To reduce component for gate power supply, a simple and robust gate drive circuit is proposed. For gating signal synchronization, full bridge invertor and pulse transformer generates on-off signals of IGBT gating with gate power simultaneously and it has very good characteristics of short circuit protection.

• 한국전자파학회논문지
• /
• 제20권10호
• /
• pp.1091-1096
• /
• 2009

본 논문에서는 공진 MTM-TL(Metamaterial Transmission Line) 등가 회로를 이용하여 방사 및 회로 파라미터의 추출 식을 제시하였다. 특히 개방 또는 단락 상태에서 방사 소자인 직렬 $R_0$와 병렬 $G_0$를 EM 시뮬레이션 또는 측정을 통해 얻은 S-parameterd(|$S_{11}$|)를 이용하여 추출한다, EM 시뮬레이션의 결과, 추출한 파라미터를 이용한 회로 시뮬레이션의 결과 그리고 측정 결과가 매우 일치함을 확인하였다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 하계학술대회 논문집 C
• /
• pp.1821-1823
• /
• 2003

We propose a high voltage dc-dc converter for CW(continuous wave) $CO_2$ laser system using a current resonant half-bridge inverter and a Cockcroft-Walton circuit. This high voltage power supply includes a 2-stage voltage multiplier driven by a regulated half-bridge series resonant inverter. The inverter drives a step-up transformer and the transformer secondary is applied to the voltage multiplier. Thus, it has high efficiency because of the less switching losses by virtue of the current resonant half-bridge inverter, and also compact size, small parasitic capacitance in the transformer stage owing to the low number of a winding turn of the step up transformer secondary by combining with Cockroft-Walton circuit. We could be obtained the maximum laser output power of 44 W and the maximum system efficiency of over 16 %.

• Journal of Power Electronics
• /
• 제14권4호
• /
• pp.661-670
• /
• 2014

A new DC/DC converter with zero voltage switching is proposed for applications with high input voltage and high load current. The proposed converter has two circuit modules that share load current and power rating. Interleaved pulse-width modulation (PWM) is adopted to generate switch control signals. Thus, ripple currents are reduced at the input and output sides. For high-voltage applications, each circuit module includes two half-bridge legs that are connected in series to reduce switch voltage rating to $V_{in}/2$. These legs are controlled with the use of asymmetric PWM. To reduce the current rating of rectifier diodes and share load current for high-load-current applications, two center-tapped rectifiers are adopted in each circuit module. The primary windings of two transformers are connected in series at the high voltage side to balance output inductor currents. Two series capacitors are adopted at the AC terminals of the two half-bridge legs to balance the two input capacitor voltages. The resonant behavior of the inductance and capacitance at the transition interval enable MOSFETs to be switched on under zero voltage switching. The circuit configuration, system characteristics, and design are discussed in detail. Experiments based on a laboratory prototype are conducted to verify the effectiveness of the proposed converter.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 1998년도 전력전자학술대회 논문집
• /
• pp.221-224
• /
• 1998

A PWM inverter with an induction motor often has a problem with a high-frequency leakage current that flows through the distributed electrostatic capacitance from the motor windings to ground. This paper presents an equivalent circuit for high-frequency leakage currents in PWM inverter feeding an induction motor, which forms an LCR series resonant circuit.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1994년도 하계학술대회 논문집 C
• /
• pp.1283-1285
• /
• 1994

A three-layered piezoelectric ceramic transducer is fabricated with three piezoelectric ceramic disk transducers and two sheets of thin insulator. Its equvalent circuit is derived from the Mason's model of a thickness-driven piezoelectric transducer. We applied the electric input near its fundamental resonant frequency to the center transducer and connect the output voltages across the left and right transducers in series to the resistor load. Then we investigate the load characteristics at resonant frequencies under various resistor loads and the frequency characteristics near the resonant frequency under no load. Moreover, symbolic expressions for input impedances, voltage ratios, resonant frequencies, and bandwidths have been derived. The values calculated from those symbolic expressions are shown to agree well with the measurement values.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2002년도 추계학술대회논문초록집
• /
• pp.328.2-328
• /
• 2002

General modeling of a resonant shunting damper has been made Iron piezoelectric sensor/actuator equation. It is found that an additional damping, which is augmented to a system, is generated by the shunt damping effect The transfer function of the tuned electrical absorber is derived for both series and parallel shunt circuit. The governing equations and associated boundary conditions are derived using Hamilton's Principle. The shunt voltage equation is also derived from the charge generated in PZT due to beam vibration. The frequency response function of the obtained mathematical model is compared with that of the tuned eledtrical absorber and experimental work. The vibration amplitude is reduced about 15 dB at targeted second mode frequency.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 1998년도 전력전자학술대회 논문집
• /
• pp.269-274
• /
• 1998

This paper describes a scaled model for PWM thyristor current-source inverter with a commutation circuit. The system consists of a 6-pulse thyristor bridge and an LC resonant circuit with thyristor switches, which offers thyristors to have turn-off capability for PWM operation with minimal switching losses. The proposed system can be used as a reactive power compensator with PWM operation for the utilitity application. There would be two advantages in the proposed system over the existing voltage source inverter. One is the low system cost due to using the conventional thyristors. Another is easy expansion of system operation voltage because th series operation of thyristor devices is already proven in HVDC system.