• Transactions on Electrical and Electronic Materials
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• v.15 no.3
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• pp.139-143
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• 2014

In this paper, an integrated low-voltage control circuit is introduced for a charge pump DC-DC boost converter. By exploiting the advantage of the integration of the feedback control circuit within CMOS technology, the charge pump boost converter offers a low-current operation with small ripple voltage. The error amplifier, comparator, and oscillator in the control circuit are designed with the supply voltage of 3.3 V and the operating frequency of 1.6~5.5 MHz. The charge pump converter with the 4 or 8 pump stages is measured in simulation. The test in the $0.35{\mu}m$ CMOS process shows that the load current and ripple ratio are controlled under 1 mA and 2% respectively. The output-voltage is obtained from 4.8 ~ 8.5 V with the supply voltage of 3.3 V.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.7
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• pp.343-351
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• 2003

In this paper, interleaved boost converter is applied as a first-stage converter in switch mode power supply. The first-stage converter plays a role to improve power factor. Interleaved Boost Power Factor Corrector(IBPFC) can reduce input current ripple as a single voltage control loop only without inner current loop, because input current is divided each 50% by two switching devices. Each converter cell is also operated in discontinuous current mode and inductor current of each converter is discontinuous. Total input current which is composed by each converter cell is continuous current. Thus, IBPFC is able to improve input current ripple. IBPFC operating in discontinuous current mode can be classified as six modes from switching state and be carried out state space averaging small signal modeling. A control transfer function is obtained according to the modeling. Not only steady-state characteristics but also dynamic characteristics is considered. Single voltage control loop is also constructed by the control transfer function. From experimental result, improvement of power factor and input current ripple are verified.

• Journal of Power Electronics
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• v.5 no.2
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• pp.104-108
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• 2005

This paper presents the performance improvement of voltage-mode controlled interleaved synchronous buck converters. This is a voltage-mode controlled scheme, where the controllers do not need an external saw-tooth generator for PWM generation and the loop design is easier. The controller implementation requires only a single error amplifier and gives almost current mode control performance. The control scheme uses voltage feedback with two loops similar to current mode control: one for the slow outer loop and the other for the faster inner PWM control loop. To improve the performance of the converter system a coupled inductor is used. This coupled inductor reduces the magnetic size and also improves the converter's transient performance without increasing the steady-state current ripple. The effectiveness of the proposed control scheme is demonstrated through PSIM simulations.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.409-413
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• 2001

This paper presents a comprehensive study result on reducing commutation torque ripples generated in brushless dc motor drives with only a single dc-link current sensor provided. In brushless dc motor drives with only a single current sensor, the commutation torque ripple suppression that is practically effective in low speed as well as high speed regions has not been reported. A proposed commutation compensation technique based on deadbeat dc-link current controller takes a closed loop control scheme and a parameter insensitive property. The proposed control method is verified through simulations and experiments.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.563-568
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• 1999

Generally the control method of wire feeding motor in welding machine has been used full-wave phase control method. The fire-angle control generates low frequency speed ripple, and it causes the output current ripple. So it results in the variation of welding condition and low welding performances such as spatter generation and bead state. For the purpose of welding performances improvement by speed controller in wire feeding motor, in this paper the constant speed control method for welding machine is proposed. The proposed system is composed of speed control loop and current control loop. As a result of experiment by using proposed constant wire feed experiment by using proposed constant wire feed speed controller, the output voltage and current waveform and metal transfer are maintained stably. And moreover the number of instantaneous short circuit occurrence is reduced remarkably.

• New & Renewable Energy
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• v.3 no.4
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• pp.69-76
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• 2007

In this paper, a PV multi-string PCS with a grid-connection is proposed. An improved MPPT algorithm for the PV multi-string PCS is suggested. Each PV string has its own MPP tracker and the proposed MPPT algorithm prevents LMPP tracking due to power ripple. In the PV PCS with single-phase inverter has a large current ripple at twice the grid frequency. The current ripple reduction algorithm without external component is suggested. Also, this paper proposes a simple control method to achieve sharing of the PV string voltage and current among the interleaved parallel boost converters. All algorithms and controllers are implemented on a single-chip microcontroller. Experimental results obtained on a 3kW prototype show high performance of the proposed PV multi-string PCS.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.685-688
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• 1992

This paper studies the commutation phenomenon in the Brushless DC Motor with the trapezoidal BEMF waveform. It is shown that the torque ripple am the speed ripple due to the phase commutation depend on driving sytem, operating speed am load condition. The effects of resistance and BEMF flat width on torque ripple are considered. Speed - torque characteristics of the motor is presented considering the phase commutation. Uncommutating current control method can attenuate the torque ripple in the low speed region, and also minimize the switching loss am switching frequency. In this paper, the commutation phenomena are verified by analytical formulation and simulation.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.3
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• pp.256-262
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• 1998

The torque of SRM depends on phase current and the derivative of inductance. But the inductance of SRM is nonlinearly changed according to rotor position angle and phase current because of saturation in magnetic circuit, and it is difficult to control the desired torque. This paper proposes inductance modeling method using ANN(Artificial Neural Network) that is used to simulate the inductance which is nonlinearly varied with rotor position and current. The torque ripple is analyzed and input voltage and current condition to reduce torque ripple is simulated by inductance model.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.255-258
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• 2007

In this paper, a PV multi-string PCS with a grid-connection is proposed. An improved MPPT algorithm for the PV multi-string PCS is suggested. Each PV string has its own MPP tracker and the proposed MPPT algorithm prevents LMPP tracking due to power ripple. In the PV PCS with single-phase inverter has a large current ripple at twice the grid frequency. The current ripple reduction algorithm without external component is suggested. Also, this paper proposes a simple control method to achieve sharing of the PV string voltage and current among the interleaved parallel boost converters. All algorithms and controllers are implemented on a single-chip microcontroller. Experimental results obtained on a 3kW prototype show high performance of the proposed PV multi-string PCS.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.362-362
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• 2000

The purpose of this thesis is to reduce force ripple of linear pulse motor(LPM) using neural network and to enhance precision. In order to this, we propose a new controller using a neural network to compensate disturbances. The structure includes adaptation block which learns the dynamics of the periodic disturbance and forces the interferences, caused by disturbances. The proposed controller compensates an unmodeled dynamics in the LPM. The neural network changes a current command to reduce position error and force ripple of the LPM. We compare proposed controller with PI controller. Simulation result shows that the proposed controller has better performance than a PI controller without neural network.