Power Gain during Partial Shade Condition with Partial Shade Loss Compensation in Photovoltaic System

Yoon, Byung-Keun,Yun, Chul,Cho, Nae-Soo,Choi, Sang-Back,Jin, Yong-Su,Kwon, Woo-Hyen The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.2

This paper presents an analysis of the power gain under partial shading conditions (PSC) when the partial shade loss is being compensated in photovoltaic(PV) system. To analyze the power gain, our study divides the mismatch loss into partial shade loss and operating point loss. Partial shade loss is defined as the power difference between a normal string and a partially shaded string at the maximum power point (MPP). Operating point loss is defined as the power loss due to the operating point shift while following the MPP of the PV array. Partial shading in a PV system affects the maximum power point tracking (MPPT) control by creating multiple MPPs, which causes mismatch losses. Several MPPT algorithms have been suggested to solve the multiple MPP problems. Among these, mismatch compensation algorithms require additional power to compensate for the mismatch loss; however, these algorithms do not consider the gain or loss between the input power required for compensation and the increased output power obtained after compensation. This paper analyzes the power gain resulting from the partial shade loss compensation under PSC, using the V-P curve of the PV system, and verifies that power gain existence by simulation and experiment.

Power Gain during Partial Shade Condition with Partial Shade Loss Compensation in Photovoltaic System

Byung-Keun Yoon,Chul Yun,Nae-Soo Cho,Sang-Back Choi,Yong-Su Jin,Woo-Hyen Kwon 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.2

This paper presents an analysis of the power gain under partial shading conditions (PSC) when the partial shade loss is being compensated in photovoltaic(PV) system. To analyze the power gain, our study divides the mismatch loss into partial shade loss and operating point loss. Partial shade loss is defined as the power difference between a normal string and a partially shaded string at the maximum power point (MPP). Operating point loss is defined as the power loss due to the operating point shift while following the MPP of the PV array. Partial shading in a PV system affects the maximum power point tracking (MPPT) control by creating multiple MPPs, which causes mismatch losses. Several MPPT algorithms have been suggested to solve the multiple MPP problems. Among these, mismatch compensation algorithms require additional power to compensate for the mismatch loss; however, these algorithms do not consider the gain or loss between the input power required for compensation and the increased output power obtained after compensation. This paper analyzes the power gain resulting from the partial shade loss compensation under PSC, using the V–P curve of the PV system, and verifies that power gain existence by simulation and experiment.

Electrical power loss model for large-area monolithic organic photovoltaic module

Lyu, Hong-kun,Jeong, Seonju,Sim, Jun Hyoung,Woo, Sungho,Kim, Kang-Pil,Shin, Jang-Kyoo,Han, Yoon Soo Elsevier 2011 CURRENT APPLIED PHYSICS Vol.11 No.1

<P><B>Abstract</B></P><P>We designed an electrical power loss model to minimize the electrical power losses in large-area monolithic organic photovoltaic (m-OPV) modules. Using the electrical power loss model, we calculated the parasitic electrical power losses on the transparent conductive oxide layer by considering the series resistance and shading losses. We fabricated a unit organic photovoltaic (OPV) cell as a reference and extracted its electrical parameters such as voltage and current density under the maximum power output condition. We calculated the electrical losses using the proposed electrical power loss model by applying these extracted parameters of the unit OPV cell. From the results of the electrical power loss model, the pattern length of the active area of a single OPV cell was determined to be 9 mm, indicating that we can place seven OPV cells in an active area of 84 mm × 90 mm.</P> <P><B>Highlights</B></P><P>► Proposed a new electrical power loss model to enhance the PCE of a monolithic OPV module. ► Calculated an optimum cell dimension using the new electrical power loss model. ► Shown the aspects of the total power loss ratio for several different shading lengths. ► Shown the aspects of the total power loss ratio for several different sheet resistances.</P>

Design of Hybrid Renewable Energy Systems with Battery/Hydrogen storage considering practical power losses: A MEPoPA (Modified Extended-Power Pinch Analysis)

Janghorban Esfahani, Iman,Ifaei, Pouya,Kim, Jinsoo,Yoo, ChangKyoo Elsevier 2016 ENERGY Vol.100 No.-

<P><B>Abstract</B></P> <P>EPoPA (Extended-Power Pinch Analysis) is a technique to integrate Hybrid Renewable Energy Systems with Battery/Hydrogen storage. Power losses of the storage components due to their inefficiency have not been considered in EPoPA as of yet. This study proposes the MEPoPA (Modified Extended-Power Pinch Analysis) to modify EPoPA to consider the power losses in Hydrogen Storage System components. The MEPoCC (Modified Extended-Power Composite Curve) and MEPoSCT (Modified Extended-Power Storage Cascade Table) are introduced as the MEPoPA graphical and numerical tools to determine the minimum targets of Required External AC (Alternating-Current) and DC (Direct-Current) Electricity Sources as well as the Hydrogen Storage System component sizes. The sensitivity analysis is conducted to investigate the effect of various Hydrogen Storage System components, such as the inverter, converters, Fuel Cell, Electrolyzer and rectifier efficiencies, on the Hydrogen Tank Electricity Capacity and the Required External AC and DC Electricity Sources. The graphical and numerical results of the MEPoPA obtained from a case study showed that the system designed by MEPoPA requires 62.19% more outsourced electricity than the system designed by EPoPA. This means that the integration potential of the Renewable Energy System with Battery/Hydrogen storage is decreased with an increase in the power losses of the storage system.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Construction of Modified Extended-Power Composite Curve. </LI> <LI> Construction of Modified Extended-Power Storage Cascade Table. </LI> <LI> Investigation of the various component efficiencies on the hydrogen tank capacity. </LI> <LI> Optimal systems comparison with and without power losses. </LI> <LI> Power losses decrease the integration potential of the battery/hydrogen system. </LI> </UL> </P>

Study on Wheel-Side Drive System with a Single Trailing Arm

Wang Bin,Chen Xinbo,Lyu Hongming,Niu Xinwei 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.5

In order to reduce unsprung mass and ensure driving comfortability, a novel electrical vehicle (EV) drive system, which integrated the wheel-side reducer and a single trailing arm, was studied in this paper. Firstly, the general structure of the drive system was studied, in which the reducer not only worked as a wheel-side reducer but also as the single trailing arm. Then, the transmission power losses were modeled by integrating different load-independent and load-independent models of power losses. Next, the experiment of the power losses test for the wheel-side drive system was conducted, which declared the patterns of power losses of electric motor and the whole drive system. Finally, the power losses of wheel-side reducer based on NEDC are studied, which illustrates oil churning and gear sliding power losses are the main types of transmission power losses. At low rotational velocities, gear friction power losses are larger than oil churning power losses. While at high rotational velocities, oil churning power losses are dominant. The transmission efficiency of the reducer based on NEDC varies among the range of 78 ~ 95 %, which depends on the torque and rotational velocity transmitted from the driving motor to EV’s wheel.

Effects of Specific Power-Loss on the Characteristics of Temperature in Magnetic Nanoparticles Subjected to External Alternating Magnetic Fields

Qiao Dongkai,Ho Chia-Chieh,Ho Ching-Yen,Chen Bor-Chyuan,Wen Mao-Yu 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.77 No.10

The variation of the specific power-loss with the anisotropy constant takes an approximately exponential form when magnetic nanoparticles (MNPs) are subjected to external alternating magnetic fields, and the distribution of the specific power-loss along the anisotropy constant shifts with temperature. Furthermore, the rate of increase in the temperature of MNPs used for hyperthermia depends significantly on the specific power-loss. Hence, the temperature characteristics of hyperthermia are affected by the specific power-loss. In this work, we develop a thermal model to analyze the effect of specific power-loss on temperature characteristics in MNPs uses for tumor hyperthermia. The results predicted by using the thermal model in this study are consistent with the available experimental data. The rate of increase of the temperature evidently varies at different temperatures due to different specific power-losses. An abrupt temperature rise occurs at the highest value in the distribution of the specific power-loss versus anisotropy constant. On the other hand, a slow temperature rise occurs when the intersection between the anisotropy constant of the MNPs and the specific power-loss distribution along the anisotropy constant at a some certain temperature corresponds with low specific power-loss.

The Optimized Design of a NPC Three-Level Inverter Forced-Air Cooling System Based on Dynamic Power-loss Calculations of the Maximum Power-Loss Range

Shi-Zhou Xu,Feng-You He 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.4

In some special occasions with strict size requirements, such as mine hoists, improving the design accuracy of the forced-air cooling systems of NPC three-level inverters is a key technology for improving the power density and decreasing the volume. First, a fast power-loss calculation method was brought. Its calculation principle introduced in detail, and the computation formulas were deduced. Secondly, the average and dynamic power losses of a 1MW mine hoist acting as the research target were analyzed, and a forced-air cooling system model based on a series of theoretical analyses was designed with the average power loss as a heat source. The simulation analyses proves the accuracy and effectiveness of this cooling system during the unit lifting period. Finally, according to an analysis of the periodic working condition, the maximum power-loss range of a NPC three-level inverter under multi cycle operation was obtained and its dynamic power loss was taken into the optimized cooling system model as a heat source to solve the power device damage caused by instantaneous heat accumulation. The effectiveness and feasibility of the optimization design based on the dynamic power loss calculation of the maximum power-loss range was proved by simulation and experimental results.

Improved switching transient model suitable for power loss evaluation of SiC-based asymmetric H-bridge power converters in SRGs

Cui, Sihang,Chen, Hao,Liu, Liang,Yang, Fan,Xu, Shuai The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.7

This paper presented an improved switching transient model of silicon carbide (SiC)-based asymmetric H-bridge (AHB) power converter for a switched reluctance generator (SRG), which takes the nonlinear phase inductance of the SRG into consideration. First, a systematic mathematic derivation is carried out and the switching transient model is established. Second, the impact of the nonlinear phase inductance of the SRG on switching transients is verified by PSpice & Simulink co-simulations. Third, a power loss model is established by the transient model through PSpice & Simulink co-simulations. The model is conducted to indicate the power loss characteristics of the SiC-based AHB power converter. Simulation results indicate that the nonlinear phase inductance of the SRG is able to accelerate the switching speed of SiC-MOSFETs, and that the SiC converter is advantageous in terms of power loss. Experimental results illustrate that the established power loss model experiences high accuracy. In addition, SiC devices are able to strengthen the power density and efficiency of a converter while reducing its heat dissipation requirements.

The Optimized Design of a NPC Three-Level Inverter Forced-Air Cooling System Based on Dynamic Power-loss Calculations of the Maximum Power-Loss Range

Xu, Shi-Zhou,He, Feng-You The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.4

In some special occasions with strict size requirements, such as mine hoists, improving the design accuracy of the forced-air cooling systems of NPC three-level inverters is a key technology for improving the power density and decreasing the volume. First, a fast power-loss calculation method was brought. Its calculation principle introduced in detail, and the computation formulas were deduced. Secondly, the average and dynamic power losses of a 1MW mine hoist acting as the research target were analyzed, and a forced-air cooling system model based on a series of theoretical analyses was designed with the average power loss as a heat source. The simulation analyses proves the accuracy and effectiveness of this cooling system during the unit lifting period. Finally, according to an analysis of the periodic working condition, the maximum power-loss range of a NPC three-level inverter under multi cycle operation was obtained and its dynamic power loss was taken into the optimized cooling system model as a heat source to solve the power device damage caused by instantaneous heat accumulation. The effectiveness and feasibility of the optimization design based on the dynamic power loss calculation of the maximum power-loss range was proved by simulation and experimental results.

듀얼 클러치 변속기 동력 손실의 정량적 분석

정호운(H. U. Jeong),이화영(H. Y. Lee),김완수(W. S. Kim),황성호(S. H. Hwang) 유공압건설기계학회 2016 유공압건설기계학회 학술대회논문집 Vol.2016 No.6

Power losses of DCT(Dual Clutch Transmission) is an import factor for powertrain power transfer efficiency and consequently the vehicle"s fuel efficiency. The net power transfer efficiency of DCT and the net power loss can be measured by a dynamometer, but it had not been possible to measure losses from specific components and its percentage contribution to the net loss. Therefore, this paper suggests a method which includes type classification of each losses from DCT and quantitative prediction of losses based on theoretical formulas. And a simulation model was developed for computing dynamic loads on each components and their rotational speed. With the simulation losses from each components, which depend on temperature, torque, and rotational speed, was calculated and then the percentage contributions to the transmission"s net loss was analyzed.