• International Journal of Precision Engineering and Manufacturing
• /
• v.3 no.3
• /
• pp.28-36
• /
• 2002

The continuously variable transmission (CVT) mechanism considered here is the output coupled type which combines the functions of a 2K-H I type differential gear unit and a V-belt type continuously variable unit (CVU). One shaft of the CVU is connected directly to the output shaft and another shaft of it is linked to the differential gear unit. It is shown that some fundamental relations (speed ratios, power flows and efficiencies) for twelve mechanisms previously described are valid by various experimental studies, six of them produce a power circulation and the others produce a power split. Parametric analysis is carried out in relation to the efficiency, speed ratio and power ratios in order to assist in the design of an optimum configuration. Some useful properties associated with power flow modes also are discussed in the output coupled type continuously variable transmission.

• Journal of Electrical Engineering and Technology
• /
• v.4 no.1
• /
• pp.79-86
• /
• 2009

This paper presents a flyback technology in power conversion aimed at increasing efficiency and power density, reducing cost and using minimum components in AC-DC conversion. The proposed converter provides these features for square waveforms and constant frequency PWM. It is designed to operate in a wide input voltage range of 75-265VAC RMS with two output voltages of 5V and 20V respectively and full load output power of 5W. The proposed converter is suitable for high efficiency and high power density application such as LCDs, TV power modules, AC adapters, motor control, appliance control, telecom and networking products.

• Journal of Power Electronics
• /
• v.10 no.1
• /
• pp.9-13
• /
• 2010

This paper proposes an input-series-output-parallel connected ZVS full bridge converter with interleaved control for photovoltaic power conditioning systems (PV PCS). The input-series connection enables a fully modular power-system architecture, where low voltage and standard power modules can be connected in any combination at the input and/or at the output, to realize any given specifications. Further, the input-series connection enables the use of low-voltage MOSFETs that are optimized for a very low RDSON, thus, resulting in lower conduction losses. The system costs decrease due to the reduced current, and the volumes of the output filters due to the interleaving technique. A topology for a photovoltaic (PV) dc/dc converter that can dramatically reduce the power rating and increase the efficiency of a PV system by analyzing the PV module characteristics is proposed. The control scheme, consisting of an output voltage loop, a current loop and input voltage balancing loops, is proposed to achieve input voltage sharing and output current sharing. The total PV system is implemented for a 10-kW PV power conditioning system (PCS). This system has a dc/dc converter with a 3.6-kW power rating. It is only one-third of the total PV PCS power. A 3.6-kW prototype PV dc/dc converter is introduced to experimentally verify the proposed topology. In addition, experimental results show that the proposed topology exhibits good performance.

• Journal of Biomedical Engineering Research
• /
• v.38 no.4
• /
• pp.183-189
• /
• 2017

Electrosurgical Unit(ESU) is medical equipment that cut or coag tissues using electrical energy. It is used in hospitals' outpatient clinic room and operating room. Improper use of an ESU may cause fatal injuries to the patient, such as burns. So, before using an ESU, make sure that it is supplying enough energy for cut and coag by measuring the output power and checking the output power cable. In this study, we developed a simple ESU power measurement system PW100 that allows anyone to check the basic output power. And PW100 can check the state of the cable associated with the output power before using ESU. Then, we compared the measured output power of the PW100 with an ESU Analyzer which was commercialized, and compared the performance. In the experiment, the output power measured by the PW100 was lower value than an ESU Analyzer's that. However, the PW100's output power measured in the 5% error range and showed stable reproducibility by a low %RSD value.

• Journal of Power Electronics
• /
• v.16 no.4
• /
• pp.1407-1414
• /
• 2016

Unlike existing pulse-width modulation (PWM) techniques, such as sinusoidal PWM and random PWM, the wavelet PWM (WPWM) technique based on a Harr wavelet function can achieve a high fundamental component for the output voltage, low total harmonic distortion, and simple digital implementation. However, the original WPWM method lacks output voltage control. Thus, the practical application of the WPWM technique is limited. This study proposes an improved WPWM technique that can regulate output voltage amplitude with the addition of a parameter. The relationship between the additional parameter and the output voltage amplitude is analyzed in detail. Experimental results verify that the improved WPWM exhibits output voltage control in addition to all the merits of the WPWM technique.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.1211-1212
• /
• 2007

In the PV power system, output of the PV array must contain inherent ripples due to the single-phase inverter. So, the function of maximum power point tracking to increase the output efficiency of PV system is degraded. Therefore, to overcome this problem, this paper presents a control strategy for the reducing ripples of the PV array output in grid-connected photovoltaic power system. The proposed control system consists of two loops; the maximum power point tracking loop using the perturbation and observation method is used to calculate the reference solar array terminal voltage(Vref) for reducing ripples of the PV array output and the PI control loop is used to regulate the solar array output voltage according to the Vref. The performance of proposing control strategy is analyzed by means of the PSCAD/EMTDC simulation and experiment. As a result, we may obtain the high performance of the proposed control strategy.

• 한국신재생에너지학회:학술대회논문집
• /
• 2006.06a
• /
• pp.202-205
• /
• 2006

In the PV power system, output of the PV array must contain inherent ripples due to the single-phase inverter. So the function of maximum power point tracking to increase the output efficiency of PV system is degraded. Therefore, to overcome this problem, this paper presents a control strategy for the reducing ripples of the PV array output in grid-connected photovoltaic power system. The proposed control system consists of two loops the maximum power point tracking loop using the perturbation and observation method is used to calculate the reference solar array terminal voltage(Vref) for reducing ripples of the PV array output and the PI control loop is used to regulate the solar array output voltage according to the Vref. The performance of proposing control strategy is analyzed by means of the PSCAD/EMTDC simulation. As a result, we may obtain the high performance of the proposed control strategy.

• Journal of Advanced Marine Engineering and Technology
• /
• v.35 no.8
• /
• pp.1070-1077
• /
• 2011

This study includes field test results for performance evaluation of a tubular turbine in marine small hydro power plant. Minimum output power of the tested turbine generator is examined with using of the measured effective head, output power and efficiency. For the rated and maximum output power tests, corrected values from the result of turbine model test are used for the performance evaluation, because experimental conditions of field test at the rated and maximum output powers are restricted correctly. Performance of the test turbine shows good conformance with the suggested guarantee values of output power and efficiency at the measured points of minimum, rated and maximum output power.

• 한국신재생에너지학회:학술대회논문집
• /
• 2009.06a
• /
• pp.49-52
• /
• 2009

Practical building integrated photovoltaic system built by Kolon E&C has been monitored and evaluated with respect to power generation, which was installed in Deokpyeong Eco Service Area in Deokpyeong, Gyeonggi, Korea. The amorphous silicon transparent PV module in this BIPV system has 44Wp in power output per unit module and 10% of transmittance with the unit dimension with $980mm{\times}950mm$. The BIPV system was applied as the skylight in the main entrance of the building. This study provided the database for the practical application of the transparent thin-film PV module for BIPV system through 11 month monitoring as well as various statistical analyses such as monthly power output and insolation. Average monthly power output of the system was 52.9kWh/kWp/month which is a 60% of power output of the previously reported data obtained under $30^{\circ}$of an inclined PV module facing south(azimuth=0). This lower power output can be explained by the installation condition of the building facing east, west and south, which was resulted from the influence of azimuth.

• Progress in Superconductivity and Cryogenics
• /
• v.16 no.4
• /
• pp.57-61
• /
• 2014

Output fluctuation which is generated in wind power farm can hinder stability of total power system. The electric energy storage (EES) reduces unstable output, and superconducting magnetic energy storage (SMES) of various EESs has the proper performance for output compensation of wind power farm since it charges and discharges large scale power quickly with high efficiency. However, because of the change of current within SMES, the electromagnetic losses occur in the process of output compensation. In this paper, the thermal effect of the losses that occur in SMES system while compensating in wind power farm is analyzed. The output analysis of wind power farm is processed by numerical analysis, and the losses of SMES system is analyzed by 3D finite element analysis (FEA) simulation tool.