• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.30-35
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• 2003

In the control system analysis and synthesis, the nonminimum phase system has some difficulties due to the undershoot behaviour and the constrained sensitivity function. SISO problems has been widely investigated in the literatures, and it is well known that the undershoot cannot be eliminated by any linear feedback control. However, the undershoot compensation in MIMO system is less studied, and this paper is to deal with the zero property and the nonminimum phase behaviour of the MIMO system. Firstly, some definitions of the zeros will be introduced. Second, some systems including nonminimum phase transmission zeros are exemplified to show that the undershoot behaviour could be eliminated by a linear feedback in MIMO systems.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.11
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• pp.1925-1930
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• 2016

Fuel cell power generation system, unlike conventional energy sources, converts chemical energy into electrical energy through electrochemical reaction of hydrogen and oxygen. This paper presents the control of interleaved multi-phase boost converter as the feasibility study on small-scale prototype electric railway vehicle application using fuel cell generation system. PSIM simulation program is to be used to implement the modeling of the electrical fuelcell as well as traction motor control with interleaved multi-phase boost converter. Comparing the input current ripple rate, two-phase interleaved boost converter is less than the boost converter. But the more multi-phase not less proportional to the ripple factor. we confirmed that the amplitude of the input current ripple rate of converter depend on duty ratio.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.1
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• pp.20-26
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• 2005

Various kinds of practical machines using the single phase induction motor (SPIM) are utilized to control both speed and torque. In particular, the capacitor-run type SPIM has the characteristic that allows the motor torque to be altered by auxiliary capacitance variation. In this study, we manifest an equivalent model having a more simplified configuration, and clarify the relationship between torque and capacitance. Also, we design an experimental controller that is able to perform speed control with ease by the phase angle control of the AC input voltage. Validity of this study is confirmed through the simulation and experimental results obtained.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2776-2779
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• 1999

This paper describes the vector control of a single-phase induction motor drive system to improve the dynamic performance for low power applications. Using auxiliary winding which is only utilized for starting, the single-phase induction motor is regarded as the unsymmetrical two-phase motor. This paper shows that the vector control of single-phase induction motor with new method achieves the high performance of the motor. The results of the new method are illustrated by the simulations.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.4
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• pp.47-52
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• 1998

As to power combining system, it is very important to achieve a high combining efficiency in order to minimize theamount of prime power needed and hence the cooling requirements, all of which translate into reduced cost. The combining efficiency is degraded in practice by variation in the amplitude and phase of the signals to be combined. In this paper, the new power combining newtork is proposed and realized which has the automatic gain and phase control system. This control system makes amplituede and phase variation of its all path equal. When the amplitude and phase variations are within 0~5dB and .+-.50.deg., the results show that high combining efficiency is maintained.

• Journal of Power Electronics
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• v.2 no.3
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• pp.212-219
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• 2002

A novel mode of parallel operation of a modular 3-phase AC-DC flyback converter for power factor correction along with tight regulation was recently analyzed and presented. The advantage of the proposed converter does not require expensive high voltage and high current devices that are normally needed in popular boost type 3-phase converter. In this paper tile detailed small signal analysis of the modular 3-phase AC-DC flyback converter is provided for control purpose and also experimental results are included to confirm the validity of the analysis.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.9
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• pp.1612-1617
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• 2008

Since most disturbance observer (DOB) approaches have been limited to minimum-phase systems (or systems having no zero dynamics), we propose a new DOB structure that can be applied to non-minimum phase systems. The new structure features an additional system, which is called as V-filter, whose role is to yield a minimum phase system when connected with the plant in parallel. In order to design the V-filter systematically we first consider a class of linear systems that can be stabilized via PID controller. By inverting the controller's transfer function, we can simply construct the filter. A convenient way of designing V-filter is presented by using an iterative linear matrix inequality (LMI) algorithm. With an illustrative example the simulation result shows that substantial improvement in the performance has been achieved compared with the control system without the DOB.

• Journal of Electrical Engineering and Technology
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• v.5 no.4
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• pp.623-630
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• 2010

This paper presents the implementation and characteristic analysis of a drive system for a three-phase permanent magnet motor with independent excitation winding that is applicable for electric bicycles. The design features improves the phase current waveform, output power, and torque by using advance angle control. This adjusts the phase angle of each phase current in relation to back EMF. In addition, a DC-side PI current control is performed through PWM generation circuit using a low-cost one-chip microcontroller and a CPLD chip, resulting in reduced system costs. Finally, the validity of this control scheme for driving electric bicycles and output/torque improvement characteristics are verified through analysis and experimental results.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.349-351
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• 1999

This paper presents a new control algorithm for series active power filters that are applied to 3-phase 3-wire and 3-phase 4-wire systems with capacitive loads. It is difficult to reduce harmonic currents in neutral lines of the 3-phase 4-wire systems using conventional series active power filter control methods. 3-phase 4-wire series active power filter systems using the proposed method in this study lower neutral line harmonics. Simulation was carried out to verify the algorithm.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.143-145
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• 2005

A typical method to control the single-phase power converter system is to utilize the zero-crossing PLL. However, this method is vulnerable to the voltage disturbance and affects the performance of controller. This paper proposes a new single-phase PLL system that is composed of the adaptive linear combiner and the PI control. The operational principle was analyzed through theoretical approach and the performance was verified through simulations with MATLAB. The proposed PLL system shows rapidness and robustness in control under the voltage disturbances such as the sag, harmonics, and phase jump.