• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.2
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• pp.339-346
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• 2017

This paper proposes a sensorless control method to improve the performance of an internal permanent magnet synchronous motor (IPMSM) control by using a full-order flux observer in a wide speed range. The conventional sensorless control method uses a constant gain for high performance at low-speed region. However, this method has drawbacks such as an increased angle error and current ripple in the high-speed region due to the fixed gain value. In order to overcome this problem, the gain of the full-order flux observer is changed by considering the angle error in the whole speed range. The proposed method minimizes the angle error for each region of the speed range by applying a relevant gain value, which improves the current ripple reduction and motor noise cancellation. The validity of proposed sensorless control method is verified by a simulation and an experiment.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.6
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• pp.565-572
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• 2013

The sensorless speed control using the improved full-order flux observer for PMSM is proposed in this paper. A conventional full-order flux observer has a drawback that the estimated flux of this observer contains the ripple component at the low speed range due to the increased gains of the convectional full-order flux observer. The improved full-order flux observer with the modified gains guarantee the improved estimation performance without ripple component at the from zero to high speed range. To identify the performance of proposed observer, the simulation and experiment are conducted and this performance is compared with the conventional full-order observer.

• Journal of Power Electronics
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• v.17 no.1
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• pp.31-40
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• 2017

A novel voltage-fed single-stage power factor correction (PFC) full-bridge converter based on asymmetric phase-shifted control for battery chargers is proposed in this paper. The attractive feature of the proposed converter is that it can operate in a wide output voltage range without an output low-frequency ripple, which is indispensable in battery charger applications. Meanwhile, the converter can maintain a high power factor and a controllable dc bus voltage over a wide output voltage range. In this paper, the realization of PFC and the operation principle of asymmetric phase-shifted control are given. A small-signal analysis of the proposed single-stage power factor correction (PFC) full-bridge converter is performed. Experimental results obtained from a 1kW experimental prototype are given to validate the feasibility of the proposed converter. The PF is higher than 0.97 over the entire output voltage range with the proposed control strategy.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.4
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• pp.247-253
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• 2000

In this paper, we deal with the full range control problem of nonlinear boiler systems subject to complex actuator constraints. Firstly, $H\infty$ loop shaping design procedure［10］ is used for the controller design. Secondly, modified high-gain feedback［11］ for the loop shaping controller is adopted for the anti-windup function and the bumpless transfer technique between controllers is proposed for the full range control of nonlinear systems. Finally, the performance of the proposed controller is demonstrated through the simulation studies.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.474-476
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• 1999

This paper presents the vector control of induction motor for traction drives. Especially, the PWM mode control method is well described to be selected as the change of speed to meet the wide speed range of the traction motor. Asynchronous space vector PWM mode and synchronous one pulse mode are basically used under the full speed range with the overmodulation PWM mode for the soft transfer between them. The validity of this proposed control scheme is verified with the simulation results.

• International Journal of Control, Automation, and Systems
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• v.6 no.4
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• pp.477-487
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• 2008

This paper proposes a new position sensorless drive for brushless DC (BLDC) motors. Typical sensorless control methods such as the scheme with the back-EMF detection method show high performance only at a high speed range because the magnitude of the back-EMF is dependent upon the rotor speed. This paper presents a new solution that estimates the rotor position by using an unknown input observer over a full speed range. In the proposed method, a trapezoidal back-EMF is modelled as an unknown input and the proposed unknown input observer estimating a line-to-line back-EMF in real time makes it possible to detect the rotor position. In particular, this observer has high performance at a low speed range in that the information of a rotor position is calculated independently of the rotor speed without an additional circuit or complicated operation process. Simulations and experiments have been carried out for the verification of the proposed control scheme.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.849-854
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• 2007

This paper describes design and tuning of a full-range Adaptive Cruise Control (ACC) with collision avoidance. The control scheme is designed to control the vehicle so that it would feel natural to the human driver and passengers during normal safe driving situations and to avoid rear-end collision in vehicle following situations. In this study, driving situations are determined using a non-dimensional warning index and time-to-collision (TTC). A confusion matrix method based on natural driving data sets was used to tune control parameters in the proposed ACC System. An ECU-Brake Hardware-in-the-loop Simulation (HiLS) was developed and used for an evaluation of ACC System. The ECU-Brake HiLS results for alternative driving situation are compared to manual driving data measured on actual traffic way. The ACC/CA control logic implemented in an ECU was tested using the ECU-Brake HiLS in a real vehicle environment.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.6
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• pp.1568-1575
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• 1990

Fatigue crack growth behavior was investigated in the center cracked plate of KS SB41 steel and the relation between the crack growth rate and various mechanical parameters was studied at small scale yielding, large scale yielding and full scale yielding. The crack opening ratio U was about 0.6-0.8 and had the larger value in the case of load control than that of strain control. Effective stress intensity factor range, .DELTA.K$_{eff}$ and J integral range, .DELTA.J were obtained from the notion of crack opening, and the crack growth rate was expressed with these values. The value of J integral range increased rapidly at stress ratio, R=0 in full scale yielding of load control test. COD value also increased rapidly with the increase of ligament net stress at large scale yielding of load control test.t.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.3
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• pp.256-264
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• 2022

The frequency power control method (FCM) which has a wide operating frequency range is adopted for induction heating (IH) cooktops. When FCM is applied to the full-bridge series resonant converter (FB-SRC) based IH system, high-frequency switching of the inverter is required compared to the half-bridge SRC (HB-SRC)-based IH system. Therefore, the switching loss of the inverter increases, and applying FCM under the condition that the inverter operating frequency range is limited is difficult. Therefore, this paper proposes a control strategy with the phase shift power control method considering that limited frequency conditions are presented. Loss analysis following the control method is performed through simulation and mathematical analysis. In addition, the validity of the proposed control strategy is verified by analyzing the heating performance following the control method through the test results of the 3,200[W] prototype.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.220-226
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• 2010

In this paper, the static overmodulation is proposed for the 2-phase full bridge inverter. The overmodulation strategy increases a fundamental output voltage and improves a voltage utilization up to the maximum in the overmodulation range. The linear modulation range and static overmodulation range are defined in the 2-phase full bridge inverter. The overmodulation strategies which increase a voltage utilization until the 4-step mode by linearization of the output voltage in overmodulation range are proposed. To maintain a linearity of the relation between a reference voltage and a fundamental output voltage, this paper suggests a compensation voltage, whose magnitude or phase is modified to the proposed control scheme. Simulation and experimentation results demonstrate the effectiveness of the proposed algorithms.