• 드라이브 ㆍ 컨트롤
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• 제17권2호
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• pp.45-54
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• 2020

The IMV is a combination of four two-way valve systems which replace a conventional four-way spool valve to improve efficiency mostly in excavator hydraulics. As the environmental regulations for construction equipment have tightened, some overseas advanced companies have released commercial excavators in which the MCV is implemented with the IMVs. Development of the IMV type MCV relies on the control algorithm as well as the robust performance of proportional flow control valves. In this study, the IMV controller was designed and verified with experiments for the excavator working unit, which determines the IMV mode of operation and the extent of the valve opening in consideration of the load conditions on hydraulic actuators. First, the open-loop controller was designed with a joystick command vs. a PSV reference current map comprising several control parameters in to compensate for the different flow characteristics and non-linearities of two-way flow control valves. Second, the closed-loop controller was designed with the PI control fed by the actuator displacement and outputs actuator percent effort equivalent to the operator's joystick command. Finally, the performance of the IMV type MCV was verified with the trajectory control of position references derived from the energy consumption test standard. Experimental results showed the control performance of the IMV developed in this study, and suggest that future studies to be conducted to advance technical progress.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.603-605
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• 1996

The SLIM used in the conveyance system has been generally developed the controller based on the slip frequency control and the VVVF method to obtain the quick response for the position control signal. This paper deals with the trust control of the SLIM by vector control with Bang-Bang condition. Also, the control system is composed of the PI controller for soft start of the SLIM and the q-axis current controller for correction in phase with Space Vector for reducing the harmonic pulsation in low speed. The processing for vector control and robust dynamic breaking control is carried out by MC80196KC micro processor and IGBT module. The proposed scheme is verified through the computer simulation and experiments for the 10KW SLIM.

• Journal of Power Electronics
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• 제11권2호
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• pp.120-131
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• 2011

This paper proposes two control strategies for the bidirectional Z-source inverters (BZSI) supplied by batteries for electric vehicle applications. The first control strategy utilizes the indirect field-oriented control (IFOC) method to control the induction motor speed. The proposed speed control strategy is able to control the motor speed from zero to the rated speed with the rated load torque in both motoring and regenerative braking modes. The IFOC is based on PWM voltage modulation with voltage decoupling compensation to insert the shoot-through state into the switching signals using the simple boost shoot-through control method. The parameters of the four PI controllers in the IFOC technique are designed based on the required dynamic specifications. The second control strategy uses a proportional plus resonance (PR) controller in the synchronous reference frame to control the AC current for connecting the BZSI to the grid during the battery charging/discharging mode. In both control strategies, a dual loop controller is proposed to control the capacitor voltage of the BZSI. This controller is designed based on a small signal model of the BZSI using a bode diagram. MATLAB simulations and experimental results verify the validity of the proposed control strategies during motoring, regenerative braking and grid connection operations.

• 전력전자학회논문지
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• 제11권2호
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• pp.127-134
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• 2006

고성능 DSP 또는 마이크로프로세서를 통해 구현되던 벡터제어를 프로그램이 가능한 소자인 FPGA를 통해 하드웨어로 구현하였다. 이를 위해 벡터제어 알고리즘을 구성하는 제어 블록들을 VHDL을 통해 모듈화 하고, 모듈화한 벡터제어 알고리즘을 FPGA에 프로그래밍 하여 하드웨어 벡터제어기를 구현하였다. 그리고 하드웨어 벡터제어기의 성능을 검증하기 위해 영구자석 동기 전동기 구동을 위한 벡터제어 시스템을 구성하고, 소프트웨어 기반 벡터제어 시스템과 벡터제어 알고리즘 연산시간 및 성능에 대한 비교연구를 수행하였다.

• 전기학회논문지
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• 제66권8호
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• pp.1207-1214
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• 2017

In the case of frequent braking, when driving downhill or long distance, conventional brakes using friction are problematic in braking safety due to brake rupture and fading phenomenon. Therefore auxiliary brakes is essential for heavy vehicles. And several research has been actively conducted to improve energy efficiency by regenerating mechanical energy into electric energy when the vehicles brake. In this paper, a voltage control method is utilized to recover the electric energy generated in the electromagnetic retarder instead of the eddy current. To regenerate the braking energy into the electrical energy, a resonant L-C circuit is configured in the retarder. The retarder can be modeled as self-excited induction generator due to its operating principle. The driving conditions according to the retarder's parameters are made into 3-D maps. Also, the voltage of the resonant circuit changing depending on the driving pulse applied to the FET was analyzed. For the control of this voltage, we proposed an algorithm using the PI controller. The controlled voltage is converted by a 3-phase AC/DC converter and then charged to a battery inside the heavy vehicles through a DC/DC converter. Electromagnetic retarder and its controller are validated using Matlab Simulink. We also demonstrate the voltage controller through the actual M-G set experiment.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 춘계학술대회 논문집 에너지변화시스템부문
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• pp.32-34
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• 2009

The field oriented control of induction motors is widely used in high performance applications. However, detuning caused by parameter disturbance still limits the performance of these drives. In order to accomplish variable speed operation, conventional PI-like controllers are commonly used. These controllers provide limited good Performance over a wide range of operation, even under ideal field oriented conditions. This paper is proposed model reference adaptive fuzzy control(MFC) and artificial neural network(ANN) based on the vector controlled induction motor drive system. Also, this paper is proposed control of speed and current using fuzzy adaption mechanism(FAM), MFC and estimation of speed using ANN. The proposed control algorithm is applied to induction motor drive system using FAM, MFC and ANN controller. Also, this paper is proposed the analysis results to verify the effectiveness of this controller.

• 조명전기설비학회논문지
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• 제29권9호
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• pp.33-41
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• 2015

To improve the power quality of distributed generation (DG) systems even in the presence of distorted grid condition, dual current control scheme of a grid-connected inverter is proposed. The proposed current control scheme is achieved by decomposing the inverter state equations into the fundamental and harmonic components. The derived models are employed to design dual current controllers. The conventional PI decoupling current controller is used in the fundamental model to control the main power flow in DG systems. At the same time, the predictive control is applied in the harmonic model to suppress undesired harmonic currents to zero quickly. To decompose the voltage inputs and state variables into the fundamental and harmonic components, the fourth order band pass filter (BPF) is designed in the discrete-time domain for a digital implementation. For experimental verification, 2kVA prototype of a grid-connected inverter has been constructed using digital signal processor (DSP) TMS320F28335. The effectiveness of the proposed strategy is demonstrated through comparative simulation and experimental results.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.27-33
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• 1997

In this paper, instantaneous controller of a single-phase PWM converter is realized using DSP. The stable PI gain of the input current and the DC link voltage control system is designed. The DC link voltage control system can be designed in continuous-time domain. But as for the input current control system, the descretizing effect cannot be ignored so it must be designed in descrete-time domain considering the calculation time. The capacitance estimating algorithm which can be acquired through the ripple voltage is proposed. By this algorithm the DC link capacitance can be estimated even under the transient state. Experimental results show the input power factor of 99.1% and the voltage variation rate of $\pm$5% according to the load variation.

• 한국해양공학회지
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• 제20권6호
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• pp.18-23
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• 2006

This paper introduces the results of the development of a new mobile digital DC-arc welding machine (DDWM). A simple PI controller is applied to the DDWM to control the output welding current that is tracking the constant setting current. Furthermore, a hot-start function, an anti-stuck function, a standby mode and an intelligential circuit breaker (ICB) are included in the DDWM. The DDWM increases welding quality and saves more power energy than a conventional welding machine. The DDWM is changed from ready mode into the standby mode, automatically, after 2-minute intervals from this unload start. Then, the DDWM is changed into ready mode, automatically, since it is reused for welding. Moreover, the DDWM increases welding quality, productivity and reduces costs of welding. So, the DDWM can make a considerable contribution to the mobile welding industries. The effectiveness of the DDWM was proven by the experimental results.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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• pp.71-72
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• 2006

This paper introduces the results of the development of a new mobile Digital DC-arc Welding Machine (DDWM). A simple PI controller is applied to the DDWM to control the output welding current tracking the constant setting current. Furthermore, a hot-start function, an anti-stuck function, a standby mode and an intelligential circuit breaker (ICB) are included in the DDWM. The DDWM increases welding quality and saves more power energy than a conventional welding machine. Because the DDWM is changed from ready mode into the standby mode automatically after 2 minutes interval from this unload start. Then the DDWM is changed into ready mode automatically since it is reused to weld. Mover, the DDWM increases welding qualify, productivity and reduces costs of welding. So, the DDWM can have a great of contribution to the mobile welding industries. The effectiveness of the DDWM was proven by the experimental results and durable test.