• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.4
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• pp.8-15
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• 2013

This paper proposes a DC-link voltage variation compensation method for a 3-level single phase converter for high-speed trains. Since 3-level NPC(Neutral Point Clamped) type converters have the split DC-link causing the inherent problem of voltage fluctuations in the upper and lower capacitors, reducing the voltage difference between the top and bottom capacitors is required. In this paper, compensation time proportional to the voltage difference is added to PWM switching time to solve the voltage variation. The compensation time is obtained by a PI controller. Simulation results demonstrate the validity of the proposed method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.553-557
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• 2000

This paper proposes the method to reduce output leakage current in single phase induction motor driven a PWM inverter. A proposed method applies to a new PWM switching algorism to reduce low-order harmonic in an inverter system with a feedback circuit of leakage current. Simulation is done to confirm a validity of method Proposed.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.310-312
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• 1989

From the viewpoint of an effective energy use, many method for reactive power compensation has been developed. Among of the reactive power compensation, this paper describes the relation of operation interpretation, filter, hysteresis width and switching time of current controlled PWM converter which has excellent reactive power compensation. This current controlled PWM convertor is excellent the view of reactive power compensation by current control method using hysteresis comparator method, but is required element of high response characteristics. Therefore this paper offers the series of data for system considering switching characteristics of switching element.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.4
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• pp.382-387
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• 1998

The adaptive hysteresis band current control method using neural network is proposed to hold the switching frequency of PWM inverter constant at any operating points of ac motor. The adaptive hysteresis band equation is derived as the teaching signal of neural network. and then the structure and learning algorithm of the neural network a are suggested. The simulation results show that the switching frequency of PWM inverter is held constant at any operating conditions of ac motor and the proposed method has good transient performance of stator current.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.13 no.6
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• pp.529-534
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• 1988

This paper describes a new method to eliminate some selected harmonics in PWM waveforms using the Walsh series which substitute the linear algebraic equations for the nonlinear equations required in the Fourier series harmonic elimination. In addition, this method is simulated to synthesize periodic PWM waveforms and compare the Walsh analysis with the FOurier analysis, Experimental results are shown that a singel-phase PWM waveforms are identified with the proposed Walsh Series.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.195-197
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• 2001

This paper presents the circuit modeling and Control methods of PWM DC/DC Converter with Isolated dual outputs. The dual output converter topology is consisted of the two switch and single secondary winding. The control algorithm which is used by an adjusted PI control methods, of Dual Output PWM DC/DC converter is proposed in this paper. The proposed adjusted PI control method has faster response characteristics than conventional PI control methods at load change. The validity of the proposed adjusted control method is verified with the several interesting simulation results.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.300-302
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• 1995

This paper describes a current control method for a single-phase PWM inverter. The proposed PWM inverter utilizes the instantaneous control method which is based on the real-time digital feedback control and the microprocessor-based deadbeat control. For the deadbeat current controller, the system's order becomes a high order and increases computation delay time. Therefore, The delay time produces current ripple. To minimize the current ripple, a new method based on deadbeat control theory for current regulation is proposed. It is constructed by a reduced-order state observer which predicts the output current in next sampling instant.

• Journal of Power Electronics
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• v.19 no.6
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• pp.1582-1590
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• 2019

A new method for reducing the common-mode current generated by the voltage variations in a two-inverter air conditioner system by applying a synchronized pulse-width modulation (PWM) strategy is proposed. The PWM signals of the master-mode inverter are generated based on the reference voltage, while those of the slave-mode inverter are output in the opposite direction when the master-mode inverter changes its switching state. However, the slave-mode control results in a mismatch between the reference voltage and the actual output voltage that is modified by synchronized control operation. The proposed method is capable of reducing and controlling this voltage error by performing signal selection in the vector space of the slave-mode inverter, which mitigates the distortion of the phase current. The efficacy of this method in reducing conducted emissions has been validated both theoretically and experimentally.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.3
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• pp.254-262
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• 1990

In the active power filter, the PWM method for controlling the power converter plays an important role for the performance and the efficiency of the filter. In this paper, a new PWM method for the single phase current source type active power filter is presented, which is intended particularly for obtaining the maximum efficiency of the compensation. This method is basically based upon the optimized injection method, but in contrast to the existing method, this method adapts the optimized injection method by putting not only the pulse width, but also the pulse position into control variables. By doing this, when the number of pulses per one cycle is N, lower order harmonics up to the Nth order can be completely eliminated by the filter. So, this method is much more efficient than any other existing method. These characteristics are well verified by the computer simulations and the experiments.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.397-400
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• 1986

The paper describes a new PWM technique, which is suitable for brushless servo drives. By taking into consideration the armature electromotive force, an appropriate switching voltage vector can be selected to enable switching rate reduction. Simulation results show better steady-state performance of this method than that of the classical technique.