• 전력전자학회논문지
• /
• 제23권2호
• /
• pp.147-151
• /
• 2018

Phase-shift fullbridge (PSFB) converter detects the current in the primary side for operation of the peak current mode controller (PCMC). The PCMC must used the slope compensation to solve the problem when the effective duty is over 0.5. The voltage response of PSFB converters has slower than that of buck converter because of slew interval even if the voltage controllers of two converters have same bandwidth. To overcome these problems, this work proposes a compensating method of current reference considering slew interval and fast response in the PSFB converter. The effectiveness of the proposed method is proven using the PSIM simulation and experiment.

• 전자공학회논문지C
• /
• 제34C권4호
• /
• pp.1-15
• /
• 1997

This paper proposes CMOS on-chip voltage and current reference circuits that operate at supply voltages between 2.5V and 5.5V without using a vonventional bandgap voltage structure. The proposed reference circuits based on enhancement-type MOS transistors show low cost, compatibility with other on-chip MOS circuits, low-power consumption, and small-chip size. The prototype was implemented in a 0.6 um n-well single-poly double-metal CMOS process and occupies an active die area of $710 um \times 190 um$. The proposed voltage reference realizes a mean value of 0.97 V with a standard deviation of $\pm0.39 mV$, and a temperature coefficient of $8.2 ppm/^{\circ}C$ over an extended temeprature range from TEX>$-25^{\circ}C$ to $75^{\circ}C$. A measured PSRR (power supply rejection ratio) is about -67 dB at 50kHz.

• 전력전자학회논문지
• /
• 제21권3호
• /
• pp.215-223
• /
• 2016

In this study, a novel rotor position sensorless estimation method of an interior permanent-magnet synchronous motor is proposed. A square-wave pulsating voltage signal is injected in the estimated synchronous reference frame. This signal is interpreted in the stationary reference frame regardless of the estimated rotor position. Thus, assuming that the position error is nearly zero is unnecessary because the variables in the estimated synchronous reference frame are not used. The rotor position can be exactly calculated from two voltage references and three sampled current feedbacks in the stationary reference frame. The proposed method is easy to implement and helps enhance the bandwidth of the current controller. The validity of the proposed method is verified by simulations and experiments.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2008년도 하계종합학술대회
• /
• pp.585-586
• /
• 2008

In this paper, a novel beta-multiplier reference current source circuit for the 800mV power-supply voltage is presented. In order to cope with the narrow input common-mode range of the OpAmp in the reference circuit, shunt resistive voltage divider branches were deployed. High gain OpAmp was designed to compensate intrinsic low output resistance of the MOS transistors. The proposed reference circuit was designed in a standard 0.18um CMOS process with nominal Vth of 420mV and -450mV for nMOS and pMOS transistor respectively. The total power consumption including OpAmp is less than 50uW.

• Journal of Electrical Engineering and Technology
• /
• 제9권2호
• /
• pp.532-540
• /
• 2014

It is necessary to measure the current of rotor for controlling the active and reactive power generated by the stator side of the doubly fed induction generator (DFIG) system. There are offset and scaling errors in the current measurement. The offset and scaling errors cause one and two times current ripples of slip frequency in the synchronous reference frame of vector control, respectively. This paper proposes a compensation method to reduce their ripples. The stator current is variable according to the wind force but the rotor current is almost constant. Therefore input of the rotor current is more useful for a compensation method. The proposed method adopts the synchronous d-axis current of the rotor as the input signal for compensation. The ripples of the measurement errors can be calculated by integrating the synchronous d-axis stator current. The calculated errors are added to the reference current of rotor as input of the current regulator, then the ripples are reduced. Experimental results show the effectiveness of the proposed method.

• 전기전자학회논문지
• /
• 제24권1호
• /
• pp.154-160
• /
• 2020

본 논문에서는 계통연계인버터용 정지좌표기반 전류제어알고리즘을 제안한다. PI 제어기는 계통 연결 인버터의 전류 제어기로 사용되고 있다. 정지좌표기반 PI 제어기를 사용할 경우, AC 신호 제어로 인하여 정상 상태 오류와 위상지연현상이 발생한다. 본 논문에서는 전향보상기를 추가하여 명령 추적 성능을 높이고 과도 응답을 개선하는 방법을 제안한다. 또한 계통 전압을 외란으로 사용하여 계통 오류 발생 시 시스템을 보호하기 위해 외란을 측정 및 제거하는 제어 방법을 제안한다. 제안된 제어 방법은 수학적으로 유도하고 전달 함수로 표현하였으며 시뮬레이션을 통하여 검증하였다.

• Journal of Electrical Engineering and Technology
• /
• 제12권1호
• /
• pp.151-160
• /
• 2017

This paper presents a new technique of reference current generator based on Kalman filter (KF) estimator for three-phase shunt active power filter (APF). The stationary reference frame (d-q algorithm) is used to transform the load currents into DC component. The harmonics of load currents are extracted and the three-phase reference currents are generated using KF estimator. The work is simulated using Matlab/Simulink platform. To validate the simulation results, an experimental test-rig have been perform using real-time control dSPACE DS1104. In addition, hysteresis current control was used to generate the switching signal for the correction of the harmonics in the system. The non-linear load were constructed with three-phase rectifier which connected in series with inductor and parallel with resistor and capacitor. The results shows that the new technique of shunt APF embedded with KF is proven to eliminate the harmonics created by the non-linear load with some improvement on the total harmonics distortion (THD).

• 전력전자학회논문지
• /
• 제3권4호
• /
• pp.399-406
• /
• 1998

본 연구에서는 SRM의 고성능 운전을 구현하기 위해 토오크를 순시적으로 제어하기 위한 방법을 제시한다. 먼저 SRM의 토오크-전류-회전자 위치각 특성을 측정에 의해 구하여 이를 기기의 모델로 설정한다. 이를 바탕으로 각 상간의 토오크중첩을 고려하여 부하와 속도의 변동에 따라 총합 발생토오크를 순시적으로 제어함으로써 맥동성분을 최소화시키는 기준토오크를 설정하고, 이 기준토오크를 추종하기 위한 기준 상전류 파형을 구한다. 이러한 기준전류를 추종하는 방안으로써 PWM에 의한 델타변조 (Delta Modulation) 기법을 사용한다. 실험과 시뮬레이션과 실험결과를 비교함으로써 제안된 방식의 타당성을 입증한다.

• Journal of Power Electronics
• /
• 제10권4호
• /
• pp.412-418
• /
• 2010

This paper proposes a new algorithm to generate a reference signal for an active power filter using a sliding-window FFT operation to improve the steady-state performance of the active power filter. In the proposed algorithm the sliding-window FFT operation is applied to the load current to generate the reference value for the compensating current. The magnitude and phase-angle for each order of harmonics are respectively averaged for 14 periods. Furthermore, the phase-angle delay for each order of harmonics passing through the controller is corrected in advance to improve the compensation performance. The steady-state and transient performance of the proposed algorithm was verified through computer simulations and experimental work with a hardware prototype. A single-phase active power filter with the proposed algorithm can offer a reduction in THD from 75% to 4% when it is applied to a non-linear load composed of a diode bridge and a RC circuit. The active power filter with the proposed reference generation method shows accurate harmonic compensation performance compared with previously developed methods, in which the THD of source current is higher than 5%.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제48권7호
• /
• pp.550-555
• /
• 1999

This paper deals with the effect of lightning impulse current on electrical characteristics of ZnO blocks used in distribution lightning arrester. The electrical characteristics of ZnO blocks are degraded by overtime impulse current, and the degraded ZnO block is brought to a thermal runaway and finally destroyed. It is therefore important to estimate the change of electrical characteristics of ZnO blocks. In this study, an impulse current generator which can produce 8/20$[\mus]$, 3[㎄] and 4/10$[\mus]$, 5[㎄] waveform is designed and fabricated to simulate the lightning impulse current of power systems. Total energy applied to the ZnO blocks at each time is 739[J] in 8/20$[\mus]$, and 523[J] in 4/10$[\mus]$, impulse current, respectively. From the experimental results, the 3rd harmonic of the leakage current increases continuously with the number of applied impulse current, but no significant changes in residual voltage and in reference voltage are observed until the ZnO block is destroyed. Also, it is confirmed that the main factor on degradation of ZnO blocks is rather the total energy applied to ZnO blocks than the peak value of the impulse current.