• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.43 no.7
• /
• pp.1206-1213
• /
• 1994

This paper presents the operation principle and design rule of the Rogowski coil which can measure the transient current and describes the calibration and application experimental results for performance evaluation. It is obtained that the response curves of the Robowski coil with the turns of 300 and the passive integrator to sinusoidal input give a good linearity up to the frequency of 500 [kHz] and the current measurement system gaving the Rogowski coil is the frequency bandwidth of 40 [Hz]~700 [kHz]. As an application experiment for the fabricated modeling power transmission line, the impulse current, which limitates the direct lightning return stroke to overhead ground wire, is measured by the Rogowski coil and its fast Fourier transformation is carried out. The equivalent circuit of the Rogowski coil considering the stray capacitances is proposed, and the theoretical analysis is in good agreement with the measurement results. Also, it is found that for high frequency domain the stray capacitance such as a distributed capacitance to the shield and the capacitance between windings of coil should be considered in designing the Rogowski coils since the resonance originates from the stray capacitance and the self-inductance of the Rogowski coil.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.6
• /
• pp.4115-4120
• /
• 2015

To ensure the transient stability of power system connected to a wind farm, wind power plant must be able to supply reactive power at the point of the common coupling(PCC). The reactive power capability of each individual wind turbine may not sufficient to maintain stability. Also, there are large reactive power losses in connection cables between wind farm and PCC. The static synchronous compensator(STATCOM) is considered for transient stability enhancement, because it provides many advantages such as the fast response time and superior reactive power support capability. In this paper, the effectiveness of a STATCOM in enhancing transient stability of power system connected to a wind farm is presented. The results of dynamic simulations show that STATCOM installed at the PCC can enhance transient stability.

• Journal of Institute of Control, Robotics and Systems
• /
• v.2 no.2
• /
• pp.115-120
• /
• 1996

In this paper, a sliding mode controller which is characterized by high accuracy, fast response and robustness is applied to speed control of AC-SERVO motor. The control input is changed to the continuous one in the boundary layer to reduce the chattering phenomenon, and the boundary layer converges to zero when the state variables of system reach to steady state values. The integral compensator is added to reduce steady state error and to provide the continuous torque reference. The acceleration which is necessary for the sliding plane is estimated by an obsever. Sliding surface is included in control input to enhance the robustness and transient response without increasing sliding mode controller gain. The proposed controller is implemented by DSP(digital signal processor). The effectiveness of the proposed scheme is demonstrated through experimental works.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.4 no.2
• /
• pp.175-183
• /
• 1999

For fast response of the dc output voltage in P\hi1'v1 converter, it is desirable that the relation of power balance of the i input and output terminals is introduced to the system modeling. In this case, controller desi밍1 is not easy since the m model is nonlinear. In this paper, a nonlinear control them${\gamma}$ using input-output feedback linearization is used to solve t the nonlinear problem of the system. By nonlinear control. the voltage transient response can be faster, and it is also p possible to control the output voltage to be constant with smaller output filter capacitance for load disturbance.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2000.11a
• /
• pp.353-360
• /
• 2000

A design of PIDA(Proportional-Integral-Derivative-Acceleration) controller for the third-order plant using the CDM(Coefficient Diagram Method) is presented. Using CDM, the closed-loop system with the designed PIDA controller can be made stable and satisfied both the transient and steady state response specifications without any adjustment. The effect of output step disturbance can also be lastly rejected. The fast step response of the controlled system can be achieved by reducing the equivalent time constant. The MATLABs simulation results show that the performances of the designed controlled system using CDM is better than the performance of the controlled system using PIDA controller designed by its own technique.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
• /
• v.3B no.1
• /
• pp.52-58
• /
• 2003

The application of a sliding mode control for improving the dynamic response of an induction motor based speed control system is presented in this paper and provides attractive features, such as fast response, good transient performance, and insensitivity to variations in plant parameters and external disturbance. However, chattering is a difficult problem for which the sliding mode control is a popular solution. This paper presents a new fuzzy-sliding mode controller for a sensorless vector-controlled induction motor servo system to practically eliminate the chattering problem for traction applications. A DSP based implementation of the speed control system is employed. Experimental results are presented using a propulsion system simulator. The performance of the drive is shown to be practically free from chattering.

• 제어로봇시스템학회:학술대회논문집
• /
• 1995.10a
• /
• pp.215-218
• /
• 1995

In this paper, a sliding mode controller (SMC) which can be characterized by high accuracy, fast response and robustness is applied to speed control of AC-SERVO motor. The control input is changed to continuous one in the boundary layer to reduce the chattering phenomenon, and the boundary layer converges to zero when the state variables of system reach to steady state values. The integral compensator is added to reduce steady state error and to provide the continuous torque reference. The acceleration which is necessary to get the sliding plane is estimated by an observer. Sliding surface is included in control input to enhance the robustness and transient response without increasing sliding mode controller gain. The proposed controller is implemented by DSP(digital signal processor). The effectiveness of the proposed control scheme for speed controller is shown by the real-time experimental results in the paper.

• Journal of Power Electronics
• /
• v.16 no.2
• /
• pp.564-571
• /
• 2016

This study proposes an adaptive neuro-fuzzy inference system (ANFIS)-based rotor position controller for brushless direct current (BLDC) motors to improve the control performance of the drive under transient and steady-state conditions. The dynamic response of a BLDC motor to the proposed ANFIS controller is considered as standard reference input. The effectiveness of the proposed controller is compared with that of the proportional integral derivative (PID) controller and fuzzy PID controller. The proposed controller solves the problem of nonlinearities and uncertainties caused by the reference input changes of BLDC motors and guarantees a fast and accurate dynamic response with an outstanding steady-state performance. Furthermore, the ANFIS controller provides low torque ripples and high starting torque. The detailed study includes a MATLAB-based simulation and an experimental prototype to illustrate the feasibility of the proposed topology.

• Journal of the korean Society of Automotive Engineers
• /
• v.13 no.5
• /
• pp.73-80
• /
• 1991

Air/fuel ratio control system for gasoline engines has been analyzed to determine the control gain of the system. In this analysis the engine is modelled to be a simple time delaying element and the ramp-and-jump method is used to control air/fuel ratio. The result shows that it is necessary to measure the air flow rate accurately to enhance the control performance. And also it is shown that the control gain must be determined in some bounded region to meet the fast dynamic response and high catalyst conversion efficiency together.

• Proceedings of the KIEE Conference
• /
• 1998.07c
• /
• pp.1143-1146
• /
• 1998

Static excitation systems with high gain and fast response times greatly aid transient stability. but at the same time tend to reduce small signal stability. The objective of the power system stabilizer(PSS) control is to provide a positive contribution to damping of the generator rotor angle swings, which are in a broad range of frequencies in the power system. Therefore, this paper shows the field test results for the GE's EX2000 PSS tuning on units at Seo-Incheon power plant. The test is to verify that the PSS response meets GE's design, criteria. The responses of generator terminal voltage, active power, field voltage and current were analyzed and PSS gain was tuned by 10 finally.