• Proceedings of the KIEE Conference
• /
• 1991.07a
• /
• pp.605-610
• /
• 1991

In inverter system for driving induction motor, the output harmonics are hamrful in induction motor drive because it leads to ripple torque and induction interference. For electrical drives using PWM(Pulsewidth Modulation) inverters and ac motors, the methods for efficiency optimal control have been developed. In this paper, two different PWM methods for inverter and voltage control technique are described. In order to reduce or minimize losses, various forms of PWM strategy such as, PM (Positive Modulation) and NM (Negative Modulation) are discussed. The results show the feasibility of obtaining practically sinusoidal output waveforms which are highly desirable in most inverter application.

• Proceedings of the KIEE Conference
• /
• 1999.07b
• /
• pp.853-855
• /
• 1999

The induction machine has been used frequently for the system that needs static speed because of its simplicity, durability, credibility and efficiency. But it is nonlinear system for its multi-variable interference. Its controller is more complicated than DC machine's one. So vector control method is needed for its high Performance control. This paper shows that vector control algorithm could be more fast and stable by using Genetic algorithm (GA) based upon Darwin's evolution theory and Mendel's genetics. Methods proposed in here are used to design induction machine's vector controller and to use GA for optimizing the controller's parameter. SIMULINK of MATLAB is used for analysis and conviction of control property

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.2 no.3
• /
• pp.84-89
• /
• 2003

The joint method and characteristics of lubricant Impregnated MC nylon and metal are analyzed. Considering the productivity and economics, two materials are Joined with the process of turning, knurling, and induction heating. The Joint strength is determined by adhesion of the melted nylon, the size of knurl, and the interference from the difference of the diameters. The parameters affecting induction heating process are analyzed. The adhesion strength of the melted nylon is measured. Finally the joint strength is analyzed in the environments of low, room, and high temperature. The nylon/metal Joined material is expected to be widely used as the sliding machine elements with good friction and shear strength.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.4 no.6
• /
• pp.579-588
• /
• 1999

This paper presents a technique for predicting the conductLu EMI(Electro Magnetic Interference) produced b by PWM inverter-induction motor drive system. To obtain the simulation models for prediction of conduct떠 n noise, high frequency model of an inverter leg with parasitic elements and multi-coil model of stator winding M are designed. Finally, the results are confirmLu from simulation and experiments.

• Proceedings of the KIEE Conference
• /
• 2000.07a
• /
• pp.470-473
• /
• 2000

Because of the continuous growth of energy consumption, and also the tendency to site power lines and pipelines along the same routes, the close proximity of high voltage structures and metallic pipelines has become more and more frequent. Moreover, normal steady state and fault currents become higher as electric networks increase in size and power. Therefore, there has been and still is a growing concern (safety of people marking contact with pipeline, risk of damage to the pipeline coating, the metal and equipment connected to pipeline. especially cathodic protection system) about possible hazards resulting from the influence of high voltage power system on metallic structures(gas pipeline, oil pipeline and water pipeline etc.). Therefore, we analyze the interference problems when the gas pipeline is buried with power cable in the same submarine tunnel. This paper present the results of the study about interference mechanism, AC corrosion, limitation of safety voltage and analysis of indiction voltage.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.9
• /
• pp.4166-4182
• /
• 2018

We consider the Device-to-Device (D2D) communications in cellular networks where each cellular user (CU) shares the same resource with multiple D2D users (DUs). In this paper, we aim to maximize the energy efficiency (EE) of the D2D networks, subject to an interference constraint required by the CU. Since the cellular and D2D communications belong to different networks, we consider to incentivize base station (BS) while assisting the DUs. To this end, we propose a Stackelberg game based interference pricing framework for the considered D2D communications in cellular networks. Unlike most of the existing methods, we use interference pricing framework to jointly address the EE resource allocation problem and the interference management in our networks rather than only improve the EE of the DUs or protect cellular networks. In particular, BS and all the users do not need all channel state information, which is more realistic in practice. In addition, two different pricing strategies are also proposed. Based on the two strategies, we analyze the equilibrium of the game. Moreover, in the first strategy, the upper and lower boundaries of the interference price are obtained. The closed-form expression is gained with a backward induction for the second strategy. Both offer valuable insights to the considered scenarios. Finally, compared with the existing work, the EE of the D2D communications is significantly improved. The advantageous performance of our scheme are demonstrated by the simulation results.

• Nuclear Engineering and Technology
• /
• v.55 no.12
• /
• pp.4570-4575
• /
• 2023

Noise and Radio-frequency interference or RFI causes a significant restriction on the Free induction Decay or FID signal detection of the Nuclear Quadrupole Resonance procedure. Therefore, using this method in non-isolated environments such as industry and ports requires extraordinary measures. For this purpose, noise reduction algorithms and increasing signal-to-noise-and-interference ratio or SNIR have been used. In this research, sodium nitrite has been used as a sample and algorithms have been tested in a non-isolated environment. The resonant frequencies for the 150 g of test sample were measured at 303 K at about 1 MHz and 3.4 MHz. The main novelty in this study was, (1) using two types of antennas in the receiver to improve adaptive noise and interference cancellation, (2) using a separate helical antenna in the transmitter to eliminate the duplexer, (3) estimating the noise before sending the pulse to calculate the weighting factors and reduce the noise by adaptive noise cancellation, (3) reject the interference by blanking algorithm, (4) pulse integration in the frequency domain to increase the SNR, and (5) increasing the detection speed by new pulse integration technique. By interference rejection and noise cancellation, the SNIR is improved to 9.24 dB at 1 MHz and to 7.28 dB at 3.4 MHz, and by pulse integration 44.8 dB FID signal amplification is achieved, and the FID signals are detected at 1.057 MHz and 3.402 MHz at room temperature.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2011.10a
• /
• pp.45-48
• /
• 2011

The electrodeless fluorescent lamp is relatively new luminaire and has been known as the high energy saving lamp which has long life and environment-friendly. But these kind of lamps have some risks to cause harmful radio interference unavoidably due to its own inductive characteristics. In this paper we measured the radio disturbance characteristics of the induction lamp with the operating frequency at 250 kHz, and compared the values with the limits of relevant standards. Finally we have estimated the interference protection distance between the induction lamps and some services around their operating frequencies, and considered the desirable future scopes and limits of the applications for these kind of lamps.

• Journal of the Korean Institute of Gas
• /
• v.4 no.3 s.11
• /
• pp.26-32
• /
• 2000

Because of the continuous growth of energy consumption, and also the tendency to site power lines and pipelines along the same routes, the close proximity of high voltage structures and metallic pipelines has become more and more frequent. Moreover, normal steady state and fault currents become higher as electric networks increase in size and power Therefore, there has been and still is a growing concern(safety of people marking contact with pipeline, risk of damage to the pipeline coating, the metal and equipment connected to pipeline, especially cathodic protection system) about possible hazards resulting from the influence of high voltage power system on metallic structures(gas pipeline, oil pipeline and water pipeline etc.). Therefore, we analyze the interference problems when the gas pipeline is buried with power cable in the same submarine tunnel. This paper present the results of the study about interference mechanism, AC corrosion limitation of safety voltage and analysis of induction voltage.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.3
• /
• pp.1251-1264
• /
• 2018

The systematic and effective design method of a Class-D current-source resonant inverter for use in an induction cooker with zero-ripple line current is presented. The design procedure is based on the principle of the Class-D current-source resonant inverter with a simplified load network model that is a parallel equivalent circuit. An induction load characterization is obtained from a large-signal excitation test-bench based on parallel load network, which is the key to an accurate design for the induction cooker system. Accordingly, the proposed scheme provides a systematic, precise, and feasible solution than the existing design method based on series-parallel load network under low-signal excitation. Moreover, a zero-ripple condition of utility-line input current is naturally preserved without any extra circuit or control. Meanwhile, a differential-mode input electromagnetic interference (EMI) filter can be eliminated, high power quality in utility-line can be obtained, and a standard-recovery diode of bridge-rectifier can be employed. The step-by-step design procedure explained with design example. The devices stress and power loss analysis of induction cooker with a parallel load network under large-signal excitation are described. A 2,500-W laboratory prototype was developed for $220-V_{rms}/50-Hz$ utility-line to verify the theoretical analysis. An efficiency of the prototype is 96% at full load.