• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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• pp.273-276
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• 1988

Forced commutated cycloconverters are capable of conversion from a fixed 3 phase source to 3 phase unrestricted variable frequency, variable voltage. They are able to accept regenerative power and the input displacement factor is controllable. Furthermore, the input current and the output current waveforms are closed to sinusoid.

• 제어로봇시스템학회논문지
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• 제21권2호
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• pp.137-144
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• 2015

In hybrid or electric vehicles, the hydraulic brake system must be controlled cooperatively with the traction motor for regenerative braking. Recently, a motor driven brake system with a PMSM (Permanent Magnet Synchronous Motor) has replaced conventional vacuum boosters to increase regenerative power. Unlike industry motor controls, additional source codes such as functional safety are essential in automotive applications to meet ISO26262 standards. Therefore, the control logic execution time increases, which also causes an extension of the motor current control period. The increased current control period makes precise motor current control challenging inhigh speed ranges where the motor is driven by high frequency. In this paper, a PWM update strategy and a time delay compensation method are suggested to improve current control and system performance. The proposed methods are experimentally verified.

• Journal of international Conference on Electrical Machines and Systems
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• 제2권2호
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• pp.171-178
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• 2013

This paper discusses to conduct experimental verification of two types of micro electric vehicles (EV) in order to realize improvement in electric mileage and shorten a charging time of the battery. First, electric double layer capacitor (EDLC) systems to use as a secondary battery are proposed. The internal resistance of EDLC is small compared with a rechargeable battery, and it is suitable for momentary charge-discharge of EV. Next, control circuits of the capacitors to increase the regenerative electric power are utilized. Then, a novel method to charge a main battery of the EV is introduced. Finally, experimental results demonstrate the validity of the proposed method.

• 한국유체기계학회 논문집
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• 제18권6호
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• pp.71-75
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• 2015

The flow and noise characteristics of the regenerative blower are evaluated experimentally. To decrease the noise of regenerative blower at a high frequency, we arrange the impeller vanes unevenly by special formula. The uneven pitch formular consists of the combination of trigonometric function. The magnitude of degree between each vanes and the control parameters of trigonometric functions are main design parameters for the uneven pitch. The flow characteristics of even and uneven impellers are tested by the fan tester and compared each results. The efficiency of a blower is calculated by the axial power using a dynamo system. The noise property of designed impeller is measured in an anechoic room. In this study, we certify that the uneven pitch impeller is effective in the noise reduction at a high frequency.

• 전력전자학회논문지
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• 제23권1호
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• pp.9-15
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• 2018

This study investigates a bidirectional quasi-Z-source inverter (Bq-ZSI) system with bidirectional power transfer capability and a modified space vector modulation scheme for reducing the ripple of the inductor current. By replacing the diode in the impedance network with an active switch, the power flow can be bidirectional. The average inductor current of the Bq-ZSI network is negative in the regenerative braking mode, thereby regenerating the power. In addition, modified space vector modulation scheme is applied to the Bq-ZSI to control shoot-through time effectively. A 5 kW prototype is built and tested to implement the proposed system. Experimental results show that the Bq-ZSI system is capable of regenerative braking of the induction motor and that the modified space vector modulation method is efficient.

• 한국철도학회논문집
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• 제18권6호
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• pp.533-542
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• 2015

본 논문은 도시철도 전동차 정차 시에 발생하는 회생전력으로 인해 전차선 가선전압 상승 시에 Converter(Forward)에서 Inverter(Reverse)로 mode 변환하여 상승된 가선전압을 AC 모선으로 환류하여 전차선 전압을 일정하게 유지하고 전동차 정차 시에 발생하는 회생전력을 재사용할 수 있는 부산도시철도의 더블 컨버터 직류 변전설비를 제안하며 전차선 직류전압 품질향상을 위해 부산도시철도 더블 컨버터 직류 변전설비에서 발생하는 Converter/Inverter mode 변환 시의 undershoot와 overshoot를 최소화할 수 있는 최적의 사이리스터 점호각을 시뮬레이션을 통하여 제시하였다.

• 유공압시스템학회:학술대회논문집
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• 유공압시스템학회 2010년도 춘계학술대회
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• pp.116-125
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• 2010

In this study, a novel hydraulic energy-regenerative system was presented from its proposal through its modeling to its control. The system was based on a closed-loop hydrostatic transmission and used a hydraulic accumulator as the energy storage system in a novel configuration to recover the kinetic energy without any reversion of the fluid flow. The displacement variation in the secondary unit was reduced, which widened the uses of several types of hydraulic pump/motors for the secondary unit. The proposed system was modeled based on its physical attributes. Simulation and experiments were performed to evaluate the validity of the employed mathematical model and the energy recovery potential of the system. The experimental results indicated that the round trip recovery efficiency varied from 22% to 59% for the test bench.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.674-682
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• 2017

This paper presents an optimal initial firing angle control based on the energy consumption and regenerative energy of a parallel multi-pulse thyristor dual converter for urban railway power substations. To prevent short circuiting the thyristor dual converter, a hysteresis band for maintaining a zero-current discontinuous section (ZCDS) is essential during mode changes. During conversion from the ZCDS to forward or reverse mode, the DC trolley voltage can be stabilized by selecting the optimal initial firing angle without an overshoot and slow response. However, the optimal initial firing angle is different depending on the line impedance of each converter. Therefore, the control algorithm for tracking the optimal initial firing angle is proposed to eliminate the overshoot and slow response of DC trolley voltage. Simulations and experiments show that the proposed algorithm yields the fastest DC voltage control performance in the transient state by tracking the optimal firing angle.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 추계학술대회 논문집
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• pp.29-32
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• 2001

The application of SRM(Switched Reluctance Motor) is dramatically increasing due to a simple mechanical structure, high efficiency and a good high speed characteristics. To control high conduction ratio in motor operation and regenerative voltage in the generator operation multi-level voltage control is effective. This paper proposes multi-level inverter to have a maximum conduction ratio of SRM. The proposed method is verified by experiments.

• 전기학회논문지
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• 제67권1호
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• pp.46-51
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• 2018

Constant slip frequency control has been conventionally used in thrust control of the linear induction motor(LIM) for magnetically levitated train. However in this paper variable slip frequency control method is presented to increase LIM efficiency according to change of driving notch. Thrust, attractive force, input power to inverter, regenerative power of the LIM are analyzed by finite element method when the train runs according to the presented control method. As a result it is proved experimentally that the electrical energy to inverter is reduced than the conventional method.