• The Transactions of the Korean Institute of Power Electronics
• /
• v.8 no.5
• /
• pp.455-462
• /
• 2003

Switching PFC converters are widely used not only to comply the power quality specification but also for maximum efficiency. However switching PFC converters generate serious electromagnetic interference(EMI). In this paper to solve this problem, we applied the APW(Anti-Phase Winding) and RPWM(Random PWM) technique to PFC boost converter and obtained good results. Simulation and experimental results show the improved harmonics and reduced EMI effect in air-conditioner system.

• Proceedings of the KIPE Conference
• /
• 2003.07b
• /
• pp.793-797
• /
• 2003

Switching PFC converters are widely used not only to comply the power quality specification but also for maximum efficiency. However switching PFC converters generate serious electromagnetic interference (EMI). In this paper to solve this problem, we applied the APW(Anti Phase Winding) and RPWM(Ran-dom PWM) technique to PFC boost converter and obtained satisfactory results. Simulation and experimental results show the improved harmonic and reduced EMI effect in air-conditioner system.

• 유체기계공업학회:학술대회논문집
• /
• 2004.12a
• /
• pp.78-82
• /
• 2004

The cross-flow fan which is used for air-conditioner indoor units were studied experimentally. The recent trend shows that the room air-conditioners need to be good-looking. According to the visual design concepts the intake regions of the fan can vary, which leads to the loss of the performance and the increase of the noise of the fan. In order to optimize the performance of the fan and minimize the aerodynamic noise for the system, the performance characteristics and the noise of the cross-flow fan have been investigated at the various conditions of the intake region of the unit.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.11a
• /
• pp.651-655
• /
• 2004

This paper studies the designing method and application for grommets, rubber material used to absorb vibration on the air conditioner compressor. The existing grommet with hardness 40 degrees, EPDM, has the high transmissibility on the compressor that causes additional structure born sound. The problem for EPDM is transformation over long time usage possibly due to its design in which stress is concentrated on a certain position. In order to resolve it, silicon material was previously used with the same design in some models. The vibration performance did improve, but the cost became high. Below are the major developments regarding improvements in compressor rubber material, vibration performance and durability through design change, and new grommet to attain cost reduction. 1 The optimum grommet design for stress even distribution through FEM methods. 2. Comparison for grommet material and design for improved transmissibility. 3. Assess for grommets durability and product applications.

• Journal of Mechanical Science and Technology
• /
• v.20 no.10
• /
• pp.1653-1661
• /
• 2006

AC induction motors have been widely used for fan motor of the air conditioner indoor unit. Noise of these AC induction motors is usually caused by the coupling effects of structural and electrical systems. The rotating torque and the noise from AC induction motor were discussed in this paper,. First, the modification of motor was carried out in order to reduce the unbalance magneto motive force between main and sub winding. Second, structural modification based on normal mode analysis and modal testing was carried out so that the fan motor does not have the natural frequencies near the 2f-line frequency. Numerical modifications through these two processes were verified by experiments, which showed that the sound pressure level at 2f-line frequency of the modified system became about 25dB less than that of conventional one.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.05a
• /
• pp.960-963
• /
• 2003

Sound intensity method is well known as a visualization technique of sound field and sound propagation in noise control. Sound intensity is a vector quantity that describes the magnitude and the direction of net flow of acoustic energy at a given position. The current measuring method is expensive and difficult to identify the noise source exactly. In this paper, we have studied the noise source identification and the characteristics of noise source of rotary compressor for air conditioner using complex sound intensity method. The new method for instantaneous sound intensity is also proposed and it is useful for transient state and steady state. The criteria of these state, select auto correlation coefficient. The advantage, simplicity and economic attribution of this method are verified by analyzing the characteristics of noise source with instantaneous sound intensity compared to mean sound intensity.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1998.04a
• /
• pp.542-547
• /
• 1998

As the concern for a global energy conservation and environmental protection are increasing, it has been more important thing to correspond with CFC depletion. Alternate refrigerants have merit such as lower global warming effect, but also have demerits such as lower efficiency, miscibility, increasing noise and poor reliability problems. Then we have to develop more efficient, silent and robust compressors to satisfying world-wide demand. In this paper, parametric study on rotary compressor muffler for a room air-conditioner was carried out to investigate the effect of important design variables on noise by using Taguchi robust design method with signal-to-noise(S/N) ratio. Taguchi method seems to be helpful for finding optimum value of design variables for noise level. We also applied neural network to find optimal value of design variables.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.11a
• /
• pp.943-946
• /
• 2007

The vibration and noise characteristic of the Axial-gap motor for an air conditioner were analyzed. Experimental Modal Analysis was performed to understand the vibration characteristic of the motor. The noise of motor was measured in a dead room. Finite Element Method was performed to find the vibration characteristic of the motor by using ABAQUS program.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.10a
• /
• pp.560-563
• /
• 1997

Sound intensity method is well known as a visualization technique of sound field and sound propagation in noise control. Sound intensity is a vector quantity that describes the magnitude and the direction of net flow of acoustic energy at a given position. The current measuring method is expensive and difficult to identify the noise source exactly. In this paper, we have studied the noise source identification and the characteristics of noise source of rotary compressor for air conditioner using complex sound intensity method. The new method for instantaneous sound intensity is also proposed and it is useful for transient state and steady state. The criteria of these states select auto correlation coefficient. The advantage, simplicity and economic attribution of this method are verified by analyzing the characteristics of noise source with instantaneous sound intensity compared to mean sound intensity.

• Journal of KSNVE
• /
• v.10 no.5
• /
• pp.873-879
• /
• 2000

Experimental investigation was conducted to study the effects of pitch angle maximum camber on the performance and noise of an axial-flow fan used in outdoor-unit of air -conditioner. For this study the axial-flow fan whose pitch angle can be varied was made and the Specific sound Pressure Level and other coefficients were measured using the anechoic fan tester. It is found that pitch angle affects more severly than the maximum camber on the fan performance. On the while the maximum camber affects much on the specific sound power level. Present results show that it is important to choose the optimum pitch angle and maximum camber to design the high-performance and low-noise axial-flow fan and specific noise measured in the anechoic fan tester can be sued effectively for the design of low-noise fan.