• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.3
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• pp.237-243
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• 2002

The single phase angle control system may become noisy when speed Is modulated with a conventional TRIAC AC controller. But this system is widely used despise of occurring sub-harmonic current because of its simply structure and low cost. Most of the vacuum cleaner drive control system regulates TRIAC's phase angle, so that it is controlled the speed. In the case of marketing product, it is not considered linearity of the speed to minimize occurring harmonic current. The sub-harmonic current reduces effectively in regulating specification TRIAC trigger phase angle. In this paper, we examined about characteristics of phase angle controller and parameter of parallel coil for eliminating sub-harmonic current.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.9
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• pp.562-568
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• 2004

The frequency and phase angle of the utility voltage are important in many industrial systems. In the three-phase system, they can be easily known by using the utility voltage vector. However, in the case of single phase system, there are some difficulties in detecting the information of utility voltage. In conventional system, the zero-crossing detection method is widely used, but could not obtain the information of utility voltage instantaneously. In this paper, the new digital PLL control using virtual two phase detector is proposed with a detailed analysis of single-phase digital PLL control for utility connected systems. The experimental results under various utility conditions are presented and demonstrate an excellent phase tracking capability in the single-phase grid-connected operation.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.5 no.2
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• pp.84-95
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• 1991

Mostly, phase control method is used to control the single phase AC power. The phase control method has some advantages such as ease to control and simple configuration. But the retardation of firing angle causes a lagging current even if load is purely resistive. So phase control causes a lagging power factor and a low efficiency at the input side in comparing with the system without switching device. A new PWM control method which can improve these defects for single phase AC power control circuit is proposed in this paper. The performances of the single phase AC power control circuit using the proposed method was investigated theoretically. Both power factor and waveform of load current can be improved better than those of the conventional methods.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1151-1154
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• 2000

Phase angle control ac drives system gains a high popularity due to their simple implementation despite the disadvantage of their poor input power factor especially for large values of phase delay angle. Furthermore it generates subharmononic current at specific phase angle. As input current of do drive systems are sinusoidal, the power factor and subharmonic current characteristics are improve. This paper presents the application of a PWM control technique of do chopper system to reduce the subharmonic current and its characteristics using single-phase dc chopper drive system of universal motor.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.5
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• pp.238-245
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• 2001

During an AC motor's start-up accelerating period, a large amount of current is required to reach to the rating speed. This is called in-rush current. This peak in-rush current can be more than about several times the operating or steady-state current in the full load rating of the motor. In-rush current is present in both and electronic ballasts. The main area of concern is the tripping of circuit breaker and fuses which can affect electrical system components From this, we can see that the electrical power controllers will be rather concerned, since they have to supply the actual current necessary to start the motor. This paper presents a new method to reducing in-rush current and energy saving of the single-phase induction motor used in air-conditioner. It can be obtained that proposed system is low cost and small size as compared with other controller. Experiments are focused on a capacitor starting single-phase induction motor. The optimal power saving and in-rush current limiting by phase angle control are verified by experimental results. Also, auxiliary winding was controlled by electronic starting switch.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.77-79
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• 2007

The phase angle of the utility voltage is used in current control of grid-tied fuel cell power converter. Therefore if the detection of phase angle is a problem, Current control is affected by the distorted phase angle. This paper presents a problem of synchronous reference frame PLL algorithm for single-phase systems and proposes compensated synchronous reference frame PLL algorithm. The proposed method helps power quality improvement of grid-tied fuel cell power converter under distorted utility conditions. Simulation and experimental results are presented to demonstrate the validity of the proposed method.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1149-1151
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• 2002

In this paper, an auxiliary winding driving system of single-phase induction motors is described. Starting charateristics variations are obtained by controlling the auxiliary winding voltage magnitude and phase angle, while the motor's main winding is directly connected to the local utility. A variable auxiliary winding voltage phase angle is shown to yield significant torque control, providing starting and braking torque. The analysis includes the determination of the relationship between the auxiliary winding voltage phase angle and the phase angle difference between the main and auxiliary winding current. The paper proposed for adjusting an auxiliary winding voltage magnitude and phase angle. Experimental results of motor's starting characteristics with using the DC-AMP and PWM inverter for auxiliary winding power supply are shown. The drive is tested using a dynamometer to experimentally verify the results of the theory.

• The Transactions of the Korean Institute of Power Electronics
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• v.1 no.1
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• pp.20-26
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• 1996

The common drive method of the single phase induction motor(SPIM) is to install a start capacitor and a centrifugal switch in series with the auxiliary winding. In this paper, the phase angle voltage sequence controller is proposed to eliminate a start capacitor and a centrifugal switch of SPIM. In comparison with the capacitor start system of SPIM, the proposed control system shows that it contributes to saving the starting current about 57% and to improving of the starting efficiency of SPIM. The proposed starting characteristics of the SPIM is obtained with this strategy through simulation and experimental results.

• Journal of Power Electronics
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• v.12 no.6
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• pp.925-934
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• 2012

Three-phase controlled converters have many applications in the utility interfacing of renewable energy sources and adjustable speed drives as a rectifier or inverter. The utility line currents of these converters have a high harmonic distortion, which is more than the harmonic standards. This paper introduces a new technique for circulating the third harmonic currents from the dc-link to the line currents to reduce their harmonic contents. The proposed system uses a single-phase PWM converter to control the angle and amplitude of the injection current for each of the firing angle of a three-phase converter. A detailed analysis is introduced to achieve a relationship between the firing angle of the three-phase controlled converter and the power angle of the PWM converter. In addition, a detailed design for the other injection path components is introduced. A simulation and experimental work is introduced to prove the mathematical derivations. Analysis, simulation and experimental results prove the superiority of the proposed technique.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.3
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• pp.280-288
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• 1997

In this paper, we will show that the torque ripple in closed-loop drives of permanent magnet stepping motors is reduced as properly selected lead angle control method. We propose an instantaneous torque equation, which is the function of lead angle, to estimate the influence on torque ripple. We design a closed-loop lead angle control system based on the proposed instantaneous torque equation and measure the instantaneous torque in various excitation modes. It is shown that torque ripple is greatly reduced, as seen from the experimental results as well as from the computer simulation results. For example, torque ripple reduced from 78.25% to 46.82% in the case of 50 PPS single-phase excitation mode operation.