• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.49 no.7
• /
• pp.475-482
• /
• 2000

This paper presents a novel power-factor correction method using customer STATCOM which generally improves the power quality of electric customers. Customer STATCOM detects the reactive currents of a induction motor(IM) and so injects compensation currents which is in 180$^{\circ}$ phase with load currents that the reactive power of IM is compensated. In particular, the paper proposes the general compensation current references in the synchronous coordinate system and makes converter output voltages using space-vector PWM. The compensation effect of customer STATCOM is confirmed through the simulation according to the operation condition of an induction motor (at no load and full load).

• Journal of Power Electronics
• /
• v.5 no.4
• /
• pp.272-281
• /
• 2005

In this paper, a simple power control scheme for a constant frequency Class-D inverter with a variable duty cycle is proposed. It is more suitable and acceptable for high- frequency induction heating (IH) jar applications. The proposed control scheme has the advantages of not only wide power regulation range but also ease of control output power. Also it can achieve a stable and efficient Zero-Voltage-Switching (ZVS) in a whole load range. The control principles of the proposed method are described in detail and its validity is verified through simulated and experimental results on 42.8kHz IGBT for induction heating rated on 1.6kW with constant frequency variable power.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.9 no.4
• /
• pp.397-404
• /
• 2004

This paper proposes a variable speed control scheme of grid-connected wind power generation systems using cage-type induction generators. The induction generator is operated in indirect vector control mode, where the d-axis current controls the excitation level and the q-axis current controls the generator torque, by which the speed of the induction generator is controlled according to the variation of the wind speed In order to produce the maximum output power. The generated power flows into the utility grid through the back-to-back PWM converter. The line-side converter controls the dc link voltage by the q-axis current control and can control the line-side power factor by the d-axis current control. Experimental results are shown to verify the validity of the proposed scheme.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.7
• /
• pp.1311-1315
• /
• 2016

Induction motor requires a rotating magnetic field for rotation. Current required to generate the rotating magnetic field is immediately magnetizing current. This magnetizing current is associated with the reactive power. Induction motor is always required reactive power. If reactive power is supplied only to the power supply side, the power factor is low. Therefore, it is to compensate the power factor by connecting capacitors in parallel to the motor terminal. If the capacitor current is greater than the magnetizing current of the motor, there is a possibility that the self-excitation occurs. High voltage generated by the self-excitation leads to insulation failure on the motor. So it is necessary to calculate the power factor correction capacitor capacity the most suitable to the extent that the magnetizing current does not exceed the capacitor current. In this study, we first computed the magnetization current and the reactive power of the induction motor and then calculates a limit of the maximum power factor by comparing the magnetizing current and the capacitor current installed in order to achieve the target power factor.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2004.10a
• /
• pp.230-233
• /
• 2004

The purpose of this study is to establish the optimal induction heating conditions of various preform types used for TR forging. The finite element model coupled electro-magnetic and transient heat transfer was employed to evaluate the distribution of temperature at the billet. Power control method was applied to control temperature of preform in induction heating because TR forging is not a continuous process. Power schedule that consists of heating and holding stage was suggested. In heating stage, power is inversely proportional to diameter of preform but the time of heating stage is directly proportional to the diameter of preform. But, in holding stage, the required power for thermal equilibrium per unit volume of the billet decreases with an increase in a diameter of billet due to the increase of efficiency.

• Journal of Advanced Marine Engineering and Technology
• /
• v.31 no.4
• /
• pp.417-424
• /
• 2007

This paper presents a solution that an analytical model for an induction motor and the formula of regenerative power and instantaneous torque are derived. based on the spiral vector. The torque is controlled linearly through variations of the slip angular velocity, based on the field acceleration method (FAM). And also PWM inverter fed induction motor drives is schemed to be easily a regenerative drive. The voltage source inverter fed induction motor drives that regenerative power occurs with back current type is presented, to easily controlled the feedback power and to proper the adaption of energy shaving drives. The experimental tests verify the performance of the FAM, proving that food behavior of the drive is achieved in the transient and steady state operating condition, and are discussed to save the power that regenerative power is measured at the operating acceleration or deceleration of servo system.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.25 no.6
• /
• pp.451-458
• /
• 2020

In this study, a trade-off analysis of a power conversion system (PCS) is performed in accordance with a power semiconductor device to establish the suitable operating frequency range for the anyplace induction heating system. A resonant network is designed under each operating frequency condition to compare and analyze the PCS losses depending on the power semiconductor device. On the basis of the simulation results, the PCS losses and frequency condition are calculated. The calculated results are then used for a trade-off analysis between Si-MOSFET and GaN-HEMT based on PCS. The suitable operating frequency range is determined, and the validity of the analysis results is verified by the experiment results.

• Proceedings of the KIPE Conference
• /
• 2003.07b
• /
• pp.639-643
• /
• 2003

We are interested in this paper on the control of an electromechanical system consisting of a doubly-fed induction generator(DFIG), driven by a prime mover that can supply or extract mechanical power, e.g., a flywheel inertia, and an induction motor(IM). The stator of the Induction machine is connected to the stator of the generator whose rotor voltage is regulated by a bidirectional converter. The main interest of this configuration is that it permits a bidirectional power flow between the motor, which may operate in regenerative mode, and the generator We propose a passivity-based controller to regulate the motor mechanical speed. Since this kind of controllers achieve stabilization via energy balancing, regulation of the power flow in the system is naturally incorporated. Simulation results are presented to illustrate the main points of our paper.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.18 no.6
• /
• pp.540-546
• /
• 2013

The induction motor is used for driving the special equipments such as warship and submarine pump due to robust structure and simple maintenance. Domestic and foreign warships use a wide range of voltages and the DC voltage sources mainly from battery. In the low voltage level, the ${\Delta}$-connection operation of induction motor can be used for the maximum power. However, the temperature of the inverter increases because of the high input current. On the other hand, Y-connection operation of the induction motor does not cause a problem of temperature because of the low input current compared to the ${\Delta}$-connection. But the lack of the supply voltage can not be avoided. Therefore, this paper suggests the algorithm of the optimum field weakening control to extend the operating range of the induction motor with maximum power in a limited thermal and DC voltage condition.

• New & Renewable Energy
• /
• v.10 no.4
• /
• pp.3-8
• /
• 2014

Both of induction generator and synchronous generator is available in the hydroelectric power plant. If the output of the power station is large, the synchronous generator is mainly used but when its output is low, the induction generator is often used. If the output capacity is small, there is a case in which induction motor is used as a generator. Torque at rated operation and start of the induction motor is different depending on the shape of the rotor. Small and medium-sized squirrel-cage induction motor is used primarily double cage rotor or deep bar. In this study, we attempt to interpret characteristics for double cage rotor or deep bar that occur when operating in the induction generator based on the parameters that have been designed and manufactured as an induction motor.