• 제어로봇시스템학회:학술대회논문집
• /
• 1992.10a
• /
• pp.75-80
• /
• 1992

This paper deals with the design scheme of the custom control circuit for optimizing the interface of peripheral devices to general-purpose controllers for the high speed digital system. When the various peripheral devices such as memory, I/O devices and buffers which operate at low speed are interfaced to the microprocessor which operates at high speed, inserting the proper wait state to the processor is required. The proposed scheme designed with random logic may be applied to the high performance graphic system like the X-terminal. This circuit provides the flexibility and system independancy for the optimum digital system design.

• Journal of Korea Society of Industrial Information Systems
• /
• v.19 no.6
• /
• pp.1-6
• /
• 2014

The delay-insensitive Null Convention Logic (NCL) asynchronous design as one of innovative asynchronous logic design methodologies has many advantages of inherent robustness, power consumption, and easy design reuses. However, transistor-level structures of conventional NCL gate cells have weakness of low speed, high area overhead or high wire complexity. Therefore, this paper proposes a new high-speed NCL gate cells designed at transistor level for high-speed, low area overhead, and low wire complexity. The proposed NCL gate cells have been compared to the conventional NCL gates in terms of circuit delay, area and power consumption.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.27 no.12
• /
• pp.87-92
• /
• 2013

In high-speed train, the EMI is generated by pantograph detachment and switching device of motor-block. Especially, the conductive noise flows through rail as return feeder influences unintended results to sub-station, transformer, etc. These phenomena were investigated by PSIM circuit analysis tool and each part of railway system is modeled by circuit elements and switching devices. Consequently, the distorted wave in return feeder current occurs by the high speed switching frequency, and the overvoltage is applied by the pantograph detachment. Also the distortion of return current is high in starting point and it decreases from the proximity of a starting point ro the end of terminal.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.57 no.2
• /
• pp.121-126
• /
• 2008

This paper analyzes the losses of a Steinmetz connection three-phase induction motor which is supplied by a single-phase source. The T-type equivalent circuit which is taken no-load losses into account is used to determine phase converter capacitive reactances at starting and rated speed by using the condition of the minimum voltage unbalance. The starting and the operating capacitor are replaced at the slip of the same voltage unbalance factor points which are depicted using two capacitive reactances. The operation characteristics are investigated by comparing with those of three-phase balanced operation to find the feasibility of single-phase operation. To analyze the losses of this motor, the output power decrease factor(OPDF), the loss ratio(LR), the no load loss ratio(NLLR), the copper loss ratio(CLR), the stator copper loss ratio(SCLR), and the rotor copper loss ratio(RCLR) are defined and simulated in the whole slip range. The simulated results show that OPDF is maintained almost uniformly, LR is low at low speed and high at high speed, CLR is higher !ban NLLR, but CLR varies concavely and NLLR varies convexly at high speed, SCLR is low at low speed and high at high speed, but SCLR varies convexly at high speed, and RCLR is nearly opposite to SCLR.

• Journal of Advanced Marine Engineering and Technology
• /
• v.17 no.3
• /
• pp.60-69
• /
• 1993

The speed control associated with dc servo motors for direct-drive applications of mobile robot is considered in this study. Robot is moved by power wheeled steering of two dc servo motors mounted to it. In order to cooperate with micro-computer and to achieve the high-performance operation of dc servo motor, speed control system is composed of a digital Phase Locked Loop and H-type drive circuit. And the motor is driven by Pulse Width Modulations. In controlling PWM, it is modified to compose of H-type drive circuit with feedback diodes and switching transistor and design of control sequence so that it may show linear characteristics. As a result, speed characteristics of motor showed linear features. In order to get data on design of PLL control system, the parameters of 80[W[ motor & robot device is measured by simple software control. The PLL speed control system is schemed and designed by leaner drive circuit and measured parameters. A complete speed control system applied to 80[W] dc servo motor showed good linearity, stability and high response. Also, it is verified that the PLL speed control system has good compatibility as a mobile robot driver.

• Proceedings of the IEEK Conference
• /
• 1998.10a
• /
• pp.779-782
• /
• 1998

This paper describes a high-speed Dual-modulus Prescaler (DMP) for RF mobile communication systems with pulse remover using selective latch technique. This circuit achieves high speed and low power consumption by reducing full speed flip-flops and using a selective latch. The proposed DMP consists of only one full speed flip-flop, a selective latch, conventional flip-flops, and a control gate. In order to ensure the timing of control signal, duty cycle problem and propagation delay must be considered. The failling edgetriggered flip-flops alleviate the duty cycle problem andthis paper shows that the propagation delay of control signal doesn't matter. The maximum operating frequency of the proposed DMP with 0.6um CMOS technology is up to 2.2㎓ at 3.3V power supply and the circuit consumes 5.24mA.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.50 no.7
• /
• pp.315-322
• /
• 2001

High speed brushless permanent magnet(PM) machines need a key technology to minimize the iron core losses in stator and the eddy current losses in the retained sleeve and magnets caused by slotting harmonics. Thus, slotless or iron-coreless brushless PM machines have been applied for a very high rotational speed and/or the ripple-free torque. Unfortunately, slotless or coreless PM machines have lower open-circuit field than slotted and/or iron-cored types, which cause to reduce power density. Fortunately, Halbach array can generate the strong magnetic field systems without additional magnetic materials. In this paper, the 4-pole Halbach array is applied to the high speed machine and is compared with the radial magnetized PM array in field system. The iron-/air-cored stator of PM machine is constructed with/without winding slots. Open circuit magnetic fields of each type are presented from the analytical method and finite element method. Consequently, it is confirmed that the Halbach array field system with slotless stator is more suitable to the high speed motor because it has high flux density, sinusoidal flux distribution than others.

• Journal of Power Electronics
• /
• v.2 no.2
• /
• pp.88-94
• /
• 2002

The demand for protection of power electronic application has during the last couple of vears increased regarding the high-power IGBT modules. Even with an active protection, a high power IGBT still has a risk of exhibiting a violent rupture in the case of a fault if IGBT Fuses do not protect it. By introducing fuses into the circuit this will increase the circuit inductance and slight inductance over-voltage during the turn-off of the diode and the IGBT. It is therefore vital when using fuses that the added inductance is kept at a minimum. This paper discuss three issues regarding the IGBT Fuse protection of adding inductance of existing High-speed and new Typower Fuse protection. First, the problem of adding inductance of exiting High-speed and new Typower Fuse DC-link circuit is treated, second a short discussion of protection of the IGBT module is done, and finally, the impect of the high frwquency loading on the currying capability of the fuses is presented.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.54 no.6
• /
• pp.284-292
• /
• 2005

Because all of the short-circuit testing laboratories have the limitation of test facilities, the synthetic making test methods have been used to estimate the short-circuit making performance of the ultra high-voltage circuit breaker as the alternative to direct test methods. So, KERI(Korea Eelctrotechnology Research institute) has completed the construction of the synthetic making test facilities using the low capacity step-up transformer method which fulfill the requirements specified in newly revised IEC 62271-100 Edition 1.1(2003) and have the testing capability up to 550kV, 63kA full-pole circuit breaker. The test facilities using the low capacity step-up transformer method presented in this paper are made up of the unit equipments such as HCS(High-speed Closing Switch), ITMC(Initial Transient Making Current) circuit and UP TR(low capacity step-up transformer) and have the operating range of 17.6$^{\circ}$ $\~$ 145.1$^{\circ}$ for testing the circuit breaker rated on up to 50kA and 43.1$^{\circ}$ $\~$ 119.6$^{\circ}$ for more than 50kA.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.35D no.12
• /
• pp.41-47
• /
• 1998

We propose a new high speed and low power SOI inverter with dynamic threshold voltage that can operate with efficient body-bias control and free supply voltage. The performance of the proposed circuit is evaluated by both the BSIM3SOI circuit simulator and the ATLAS device simulator, and then compared with other reported SOI circuits. The proposed circuit is shown to have excellent characteristics. At the supply voltage of 1.5V, the proposed circuit operates 27% faster than the conventional SOI circuit with the same power dissipation.