• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.119-121
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• 2001

This paper presents steady state analysis of single-phase line-start motor. 2-phase motor transformation is performed to consider the different specifications between main and auxiliary windings. The symmetrical coordinates transformation is applied to solve the unbalanced magnetic field. The validity of analysis method is verified by comparing to experiments.

• Journal of Power Electronics
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• v.14 no.3
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• pp.572-579
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• 2014

As a non-linear time variant system, the four-quadrant line converter of an electric multiple unit (EMU) was expressed by linear time periodic functions near an operating point and modeled by a steady-state harmonic domain matrix. The components were then combined according to the circuit connection and relations of the feedback control loops to form a complete converter model. The proposed modeling method allows the study of the amplitude of harmonic impedances to explore harmonic coupling. Moreover, the proposed method helps provide a better design for the converter controllers, as well as solves the problem in coordination operation between the EMUs and the AC supply. On-site data from an actual $CRH_2$ high-speed train were used to validate the modeling principles presented in the paper.

• Transactions of the Society of Information Storage Systems
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• v.3 no.4
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• pp.167-172
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• 2007

The recently-developed off-line learning control approaches for the rejection of periodic disturbances utilize the specific property that the learning system tends to oscillate in steady state. Unfortunately, the prior works have not clarified how closely the learning system should approach the steady state to achieve the rejection of periodic disturbances to satisfactory level. In this paper, we address this issue extensively for the class of linear systems. We also attempt to remove the effect of other aperiodic disturbances on the rejection of the periodic disturbances effectively. In fact, the proposed learning control algorithm can provide very fast convergence performance in the presence of aperiodic disturbance. The effectiveness and practicality of our work is demonstrated through mathematical performance analysis as well as various simulation results.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.648-650
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• 2002

SPLSSM may operate with very high efficiencies and near unity power factor, SPLSSM has been shown to be capable of desirable steady state performance, but is known to have undesirable staring performance because starting asynchronously by means of an induction cage, it operates in steady state performance of a PM motor. This combination provides the steady state performance of a permanent magnet motor without the need for an expensive drive system. However, that combination makes it difficult to analyze the transient behaviors. This paper investigates the behaviors of Single-Phase Line-Start Synchronous Motor using finite element method combined analytic method. It is shown that finite element modeling is capable of giving accurate prediction of performances. Varying the value of capacitance and material of permanent magnet shows the effect on the dynamic characteristics in this paper.

• Journal of Power Electronics
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• v.15 no.2
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• pp.346-355
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• 2015

On the basis of the conventional PID control algorithm, a modified adaptive PID (MA-PID) control algorithm is presented to improve the steady-state and dynamic performance of closed-loop systems. The proposed method has a straightforward structure without excessively increasing the complexity and cost. It can adaptively adjust the values of the control parameters ($K_p$, $K_i$ and $K_d$) by following a new control law. Simulation results show that the line transient response of the MA-PID is better than that of the adaptive digital PID because the differential coefficient $K_d$ is introduced to changes. In addition, experimental results based on a FPGA indicate that the MA-PID control algorithm reduces the recovery time by 62.5% in response to a 1V line transient, 50% in response to a 500mA load transient, and 23.6% in response to a steady-state deviation, when compared with the conventional PID control algorithm.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.64-69
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• 2004

The work presented here deals with controller design using error model constructed with proportional control ramp response. The design aims at the improvement of transient response, steady-state error reduction with stability preservation, generation of the consistent contour error through the proportional gain regulation of a mismatched system. The first step is to generate tracking-error curve with proportional control only and decide the added error signal shape on the error curve. The next is to construct a table for the steady-state loop gain with step input. The table is used for selecting the proportional gain. The effectiveness of the proposed controller is confirmed through the simulation and experiment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.1
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• pp.14-17
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• 2007

Power system restoration following a massive blackout starts with re-energizing primary restorative transmission systems at first. The comparison of the TLCC(transmission line charging capacity) and the RPC(reactive power capability) of related black-start generator should be considered in this stage because overvoltage can be caused by self-excitation at the generator when the RPC is smaller than the TLCC. The RPC can be decided by two criteria. One is stator end core heating, and the other is steady state stability. RPC in steady state stability area has been found based on a synchronous reactance Xd. This paper presents RPC limit of salient pole machine which is different from that of non-salient pole machine in steady state stability area and shows derivation process about that.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.3
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• pp.81-87
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• 2006

In this paper, the belt-pulley mechanical loss is investigated. A bondgraph model for the mechanical loss is developed from the viewpoint of the power flow by assuming that all power losses are attributed to the torque loss. The mechanical loss model consists of transient and steady state part. The coefficients of the power loss model are obtained from the experiments. It is found from the simulations and experiments that the steady state loss depends on the line pressure, input torque and rotational speed while the transient loss depends on the rotational speed, shift speed and the inertial torque.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.5
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• pp.470-477
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• 1990

Singh's multi-level method is extended to the optimal tracking control of a large interconnected dynamical system which has coupled states and coupled inputs. The steady-state tracking error and a convergence condition for the extended multi-level method are derived analytically and the results show that the steady-state tracking error and a convergence rate have to be compromised. Also, a new multi-level method which is advantageous over the Singh's method in steady-state tracking error and computational burden is proposed by introducing nominal inputs into the performance index. The resulting feedback gain matrix and the compensation vector are optimal for all initial conditions so that eventual on-line computation is minimal.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1072-1077
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• 2006

In this paper a novel 3-phase line interactive UPS(Uninterruptible Power Supply) system with parallel-series active power-line conditioning capability using AC line reactor and two four-leg PWM VSCs(Voltage Source Converters) is proposed. And the strategy of voltage control in proposed UPS system is explained. The objective of voltage control in parallel(shunt) and series PWM VSC of proposed UPS system is to guarantee satisfactory characteristics in steady state and transient state.