• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2004년도 ICCAS
• /
• pp.389-394
• /
• 2004

A Fuzzy Logic Sliding Mode Control or FLSMC for the uninterruptible power system (UPS) is presented, which is tracking a sinusoidal ac voltage with specified frequency and amplitude. The FLSMC algorithm combines feedforward strategy with the Variable Structure Control (VSC) or Sliding Mode Control (SMC) and fuzzy logic control. The control function is derived to guarantee the existence of a sliding mode. FLSMC has an advantage that the stability of FLSMC can be proved easily in terms of VSC. Furthermore, the rules of the proposed FLSMC are independent of the number of system state variables because the input of the suggested controller is fuzzy quantity sliding surface value. Hence the rules of the proposed FLSMC can be reduced. The simulation results illustrate that the purposed approach gives a significant improvement on the tracking performances. It has the small overshoot in the transient and the smaller chattering in the steady state than the conventional VSC. Moreover, its can achieve the requirements of robustness and can supply a high-quality voltage power source in the presence of plant parameter variations, external load disturbances and nonlinear dynamic interactions.

• 전력전자학회논문지
• /
• 제8권1호
• /
• pp.89-97
• /
• 2003

PWM 인버터에 의해 구동리근 유도전동기에 발생되는 고주파 커먼 모드 전압은 전도성 EMI, 전통기 접지전류, 베어링 전류 및 다른 원치 않는 결과의 주원인이 된다. 인버터 제어의 무효벡터 스위칭 상태는 나머지 유효벡터 스위칭 상태에 비교하여 큰 커먼 모드 전압을 일으킨다. 그러므로 이 논문은 커먼 모드 전압을 완화하는 스위칭기법을 다룬다. 즉 정현파 PWM 기법을 기본으로 한 커먼 모드 전압 제거방법을 제안하였다. PWM 신호는 각자의 정현과 기준신호와 120$^{\circ}$위상차가 나는 3개의 캐리어 파형과 비교하여 발생된다. 시뮬레이션과 실험적 결과는 제안된 PWM 기법에서 커먼 모드 전압이 종래의 PWM 기법보다 약 66% 더 저감됨을 보였다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2007년도 하계학술대회 논문집
• /
• pp.403-405
• /
• 2007

This paper presents the over-modulation strategy and indirect vector control drive of NPC type PWM inverter. NPC inverter has three level phase voltage output.It can perform in high voltage through assembling switching components. It has less harmonics and surge voltage stress at motor terminals than the 2 level inverter in same switching frequency through 3 level voltage. The conventional railway vehicle has used the vector control to MI=0.907 and the slip-frequency control from MI=0.907 to six-step mode. The slip-frequency control has bad motive power and slow torque control response. But vector control has good motive power and can instant torque control. In this paper, output voltage is controlled linearly from linear region to six-step mode by using over-modulation strategy. And NPC inverter is used.

• Journal of Power Electronics
• /
• 제12권1호
• /
• pp.145-156
• /
• 2012

These days, the application of electronic power transformers (EPTs) is expanding in place of ordinary power transformers. These transformers can transmit power via three or four wire converters. Their dynamic performance is extremely important, due to their complex structure. In this paper, a new method is proposed for improving the dynamic performance of distribution electronic power transformers (DEPT) by using sliding mode control (SMC). Hence, to express the dynamic characteristics of a system, different factors such as the voltage unbalance, voltage sag, voltage harmonics and voltage flicker in the system primary side are considered. The four controlling aims of the improvement in dynamic performance include: 1) maintaining the input currents so that they are in sinusoidal form and in phase with the input voltages so they have a unity power factor, 2) keeping the dc-link voltage within the reference amount, 3) keeping the output voltages at a fixed amount and 4) keeping the output voltages in sinusoidal and symmetrical forms. Simulation results indicate the potential and capability of the proposed method in improving DEPT behavior.

• 전기전자학회논문지
• /
• 제14권2호
• /
• pp.1-8
• /
• 2010

본 논문에서는 대기전력을 줄일 수 있는 Green Mode Power IC 회로를 설계하였다. 이 회로는 switch mode power supply(SMPS)을 구동하기 위한 PWM 기능을 가지고 있으며, 불필요한 소비전력을 제거하기 위해 burst mode와 skip mode 구간을 만들고 대기전력을 낮출 수 있도록 외부의 Power MOSFET에 의해 제어된다. 제안한 회로는 KEC 30V-High Voltage 0.5um CMOS process를 이용하여 시뮬레이션 하였다. 회로 내부는 크게 voltage regulator 회로, voltage reference 회로, UVLO(Under Voltage Lock Out)회로, Ibias 회로, green 회로, PWM 회로, OSC 회로, protection회로, control 회로, Level shift&Driver 회로로 구성되어 있다. 시뮬레이션 결과로부터 회로 동작 시 각 블록의 소비전류를 측정하여 확인한 결과 블록 별 전류총합이 1.29mA이었고, 이 값은 목표 설계치인 1.3mA을 충족시킴을 입증하였다. 이 값은 기존 IC의 소비전류보다 1/2이상 줄어든 값이며, 대기모드로 동작할 경우는 전력소비를 1W 미만까지 줄일 수 있었다.

• Journal of Power Electronics
• /
• 제15권4호
• /
• pp.1026-1034
• /
• 2015

In this paper, a unified control strategy using the current space vector modulation (CSVM) technique is proposed and applied to a bidirectional three-phase DC/AC converter. The operation of the converter changes with the direction of the power flow. In the charging mode, it works as a buck type rectifier; and during the discharging mode, it operates as a boost type inverter, which makes it suitable as an interface between high voltage AC grids and low voltage energy storage devices. This topology has the following advantages: high conversion efficiency, high power factor at the grid side, tight control of the charging current and fast transition between the charging and discharging modes. The operating principle of the mode analysis, the gate signal generation, the general control strategy and the transition from a constant current (CC) to a constant voltage (CV) in the charging mode are discussed. The proposed control strategy has been validated by simulations and experimental results obtained with a 1kW laboratory prototype using supercapacitors as an energy storage device.

• Journal of Electrical Engineering and Technology
• /
• 제12권5호
• /
• pp.1970-1979
• /
• 2017

Ultra Lift Luo Converter (ULC) gained considerable research interest in recent years. The stability analysis of voltage mode and peak current mode controlled ULC in continuous conduction mode is analyzed in this paper. The Eigen value theory is used for the stability analysis of voltage mode controlled ULC. Then to characterize the dynamics of inner current loop, the expressions of closed loop transfer function and loop gain are determined. An algorithm has been developed to analyze the stability of the peak current mode controlled ULC. The theoretical results are correlated with the simulation results obtained using PSIM 9.1(SMARTCTRL 1.0) software. Finally it is proposed to fabricate a prototype and validate the performance by suitable experimental setup.

• 전기학회논문지
• /
• 제65권3호
• /
• pp.511-519
• /
• 2016

This paper is proposed control algorithm for the using thyristor of the parallel dual converter for Urban railway power supply in order to return the regenerative power generated by regenerative braking in urban railway train. Conventional control algorithm of Thyristor dual converter for urban railway power supply has voltage variation within a control range of hysteresis band. The purposed control algorithm of the parallel thyristor dual converter is to maintain a constant voltage without voltage variation in accordance with variable load through the Sequential mode change. And the control algorithm need calculating optimum initial firing angle to consider magnitude of the load current slope. For this purpose, Proposed algorithm for sequential conversion mode of the dual converter was verified by applying for the simulation.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2000년도 전력전자학술대회 논문집
• /
• pp.351-354
• /
• 2000

This paper deals with the voltage amplitude control in inverter systems which can regenerate the excessive DC power from DC bus line to AC supply in substations for traction systems. To maintain the magnitude of output fundamental voltage constant in spite of the variation of input DC voltage inverters are operated in symmetrical $\alpha$-conduction mode with the range of $120^{\circ}$<$\alpha$<$180^{\circ}$ To match the output voltage of the inverter systems with AC supply voltage harmonic reduction techniques are also investigated. Computer simulations are carried out to verify the validity of the proposed systems.

• Journal of Power Electronics
• /
• 제5권3호
• /
• pp.180-189
• /
• 2005

In this paper a DSP based control scheme for the interleaved boost converter is presented. The mathematical model for the interleaved boost converter operating in a continuous inductor current mode is developed. A state-space averaging technique is used for modeling the converter system. A fixed frequency sliding mode controller is designed to ensure current distribution between the two converter modules and to achieve the load voltage regulation simultaneously. Necessary and sufficient conditions, using variable structure theory, are derived for the sliding mode to exist. The range of sliding mode controller coefficients is also determined. The designed controller capability, load distribution among the individual boost cells and load voltage regulation against source and load disturbances, are demonstrated through PSIM simulation results. A real-time controller based on ADMC401 DSP is developed. Experimental results are provided to validate the proposed control scheme.