Edge Coil Force Fitting and Current Optimal Commutation Algorithm for Magnetic Levitation Planar Motor With Moving Magnet

2020 ◽  
Author(s):  
Haobo Sun ◽  
Yu Zhu ◽  
Kaiming Yang ◽  
Sen Lu
Keyword(s):  
Heat Loss ◽  
Magnetic Levitation ◽  
Weighting Function ◽  
Coil Current ◽  
Coil Array ◽  
Rbf Network ◽  
Switching Algorithm ◽  
Instantaneous Current ◽  
The Difference ◽  
Edge Force

Abstract In this paper, edge coils are added to the commutation algorithm of the coil array. In order to reduce the theoretical modeling error of the edge coil force, a method of edge coil force fitting based on radial basis function (RBF) network is proposed. The obtained attenuation function of edge force can replace the weighting function in the switching algorithm, so it can effectively reduce the current density of the central coils and the heat loss power of the coil array. On this basis, a non-iterative current optimal commutation algorithm is proposed. The algorithm takes the weighted sum of the 2-norm of the coil current and the 2-norm of the difference between the coil current and the saturation current as the optimization objective, and obtains the analytical expression of the instantaneous current by solving the Karush Kuhn Tucker (KKT) equation. The results of simulation show that, compared with the direct decoupling algorithm with weighting function, the proposed commutation algorithm can reduce the heat loss power of the coil array and allow the translator to provide greater acceleration under the same maximum current limitation.

scholarly journals Composite Distribution Solution for Minimizing Heat Loss in a Pyrolysis Reactor

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Werner O. Filtvedt ◽  
Morten Melaaen ◽  
Arve Holt ◽  
Massoud Javidi ◽  
Birger Retterstøl Olaisen
Keyword(s):  
Heat Loss ◽  
Reaction Chamber ◽  
Inlet Temperature ◽  
Chemical Reactors ◽  
Normal Procedure ◽  
Pyrolysis Reactor ◽  
The Difference ◽  
Distribution Plate ◽  
Composite Distribution ◽  
Novel Design

The article presents a novel design for a distribution plate. The solution is suitable for a reactor vessel where a reactant gas needs to be maintained at a different temperature from the reaction chamber in order to avoid unwanted occurrences, such as clogging of the distribution plate. A normal procedure involves cooling of the distribution plate which is reported to either increase heat loss substantially or yield insufficient temperature in parts of the reaction chamber. The problem is especially important for reactors where the difference in reactant inlet temperature and desired reaction temperature is large. The investigated design utilized materials of very different thermal conductivity to only cool specific parts of the distribution arrangement and thereby minimize heat loss. Our system is a distribution plate for use in a fluidized bed reactor for silane pyrolysis. However, the solution is general and may be utilized in many types of vessels and chemical reactors.

Construction and Experimental Study of an Elevation Linear Fresnel Reflector

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
J. D. Nixon ◽  
P. A. Davies
Keyword(s):  
Heat Loss ◽  
Thermal Efficiency ◽  
Theoretical Models ◽  
Loss Coefficient ◽  
Heat Transfer Fluid ◽  
Stagnation Temperature ◽  
Model Predictions ◽  
The Difference ◽  
Predicted Values ◽  
Linear Fresnel Reflector

This paper outlines a novel elevation linear Fresnel reflector (ELFR) and presents and validates theoretical models defining its thermal performance. To validate the models, a series of experiments were carried out for receiver temperatures in the range of 30–100 °C to measure the heat loss coefficient, gain in heat transfer fluid (HTF) temperature, thermal efficiency, and stagnation temperature. The heat loss coefficient was underestimated due to the model exclusion of collector end heat losses. The measured HTF temperature gains were found to have a good correlation to the model predictions—less than a 5% difference. In comparison to model predictions for the thermal efficiency and stagnation temperature, measured values had a difference of −39% to +31% and 22–38%, respectively. The difference between the measured and predicted values was attributed to the low-temperature region for the experiments. It was concluded that the theoretical models are suitable for examining linear Fresnel reflector (LFR) systems and can be adopted by other researchers.

A Physically Based Algorithm for Non-Blackbody Correction of Cloud-Top Temperature and Application to Convection Study

2014 ◽  
Vol 53 (7) ◽  
pp. 1844-1857 ◽  
Author(s):  
Chunpeng Wang ◽  
Zhengzhao Johnny Luo ◽  
Xiuhong Chen ◽  
Xiping Zeng ◽  
Wei-Kuo Tao ◽  
...  
Keyword(s):  
Brightness Temperature ◽  
Weighting Function ◽  
Convective Cloud ◽  
Transfer Model ◽  
Height Range ◽  
Convective Clouds ◽  
Physically Based ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
The Difference ◽  
Cloud Top Temperature

AbstractCloud-top temperature (CTT) is an important parameter for convective clouds and is usually different from the 11-μm brightness temperature due to non-blackbody effects. This paper presents an algorithm for estimating convective CTT by using simultaneous passive [Moderate Resolution Imaging Spectroradiometer (MODIS)] and active [CloudSat + Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO)] measurements of clouds to correct for the non-blackbody effect. To do this, a weighting function of the MODIS 11-μm band is explicitly calculated by feeding cloud hydrometer profiles from CloudSat and CALIPSO retrievals and temperature and humidity profiles based on ECMWF analyses into a radiation transfer model. Among 16 837 tropical deep convective clouds observed by CloudSat in 2008, the averaged effective emission level (EEL) of the 11-μm channel is located at optical depth ~0.72, with a standard deviation of 0.3. The distance between the EEL and cloud-top height determined by CloudSat is shown to be related to a parameter called cloud-top fuzziness (CTF), defined as the vertical separation between −30 and 10 dBZ of CloudSat radar reflectivity. On the basis of these findings a relationship is then developed between the CTF and the difference between MODIS 11-μm brightness temperature and physical CTT, the latter being the non-blackbody correction of CTT. Correction of the non-blackbody effect of CTT is applied to analyze convective cloud-top buoyancy. With this correction, about 70% of the convective cores observed by CloudSat in the height range of 6–10 km have positive buoyancy near cloud top, meaning clouds are still growing vertically, although their final fate cannot be determined by snapshot observations.

scholarly journals A Novel TODIM with Probabilistic Hesitant Fuzzy Information and Its Application in Green Supplier Selection

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-26
Author(s):  
Xiaoli Tian ◽  
Meiling Niu ◽  
Jiangshui Ma ◽  
Zeshui Xu
Keyword(s):  
Weighting Function ◽  
Multiple Criteria Decision Making ◽  
Decision Makers ◽  
Sensitivity Analyses ◽  
Fuzzy Information ◽  
Probability Weighting Function ◽  
The Difference ◽  
The Stability ◽  
Gains And Losses

TODIM is a well-known multiple-criteria decision-making (MCDM) which considers the bounded rationality of decision makers (DMs) based on prospect theory (PT). However, in the classical TODIM, the perceived probability weighting function and the difference of the risk attitudes for gains and losses are not consistent with the original idea of PT. Moreover, probabilistic hesitant fuzzy information shows its superiority in handling the situation that the DMs hesitate among several possible values with different possibilities. Hence, a novel TODIM with probabilistic hesitant fuzzy information is proposed in this paper to simulate the perceptions of the DMs in PT. To show the advantages of the proposed method, a novel TODIM is combined with hesitant fuzzy information. Finally, a case study is carried out to demonstrate the feasibility of the proposed method, and a series of comparative analyses and the sensitivity analyses are used to show the stability of the proposed method.

Effect of heating rate on evaporative heat loss in the microwave-exposed mouse

1982 ◽  
Vol 53 (2) ◽  
pp. 316-323 ◽  
Author(s):  
C. J. Gordon
Keyword(s):  
Body Temperature ◽  
Heat Loss ◽  
Heat Dissipation ◽  
Dew Point ◽  
Whole Body ◽  
Evaporative Heat Loss ◽  
Heat Absorption ◽  
Deep Body Temperature ◽  
The Difference ◽  
Body Heat

Male CBA/J mice were administered heat loads of 0–28 J X g-1 at specific absorption rates (SARs) of either 47 or 93 W X kg-1 by exposure to 2,450-MHz microwave radiation at an ambient temperature of 30 degrees C while evaporative heat loss (EHL) was continuously monitored with dew-point hygrometry. At an SAR of 47 W X kg-1 a threshold heat load of 10.5 J X g-1 had to be exceeded before EHL increased. An approximate doubling of SAR to 93 W X kg-1 reduced the threshold to 5.2 J X g-1. Above threshold the slopes of the regression lines were 1.15 and 0.929 for the low- and high-SAR groups, respectively. Thus the difference in threshold and not slope attributes to the significant increase in EHL when mice are exposed at a high SAR (P less than 0.02). In separate experiments a SAR of 47 W X kg-1 raised the deep body temperature of anesthetized mice at a rate of 0.026 degrees C X s-1, whereas 93 W X kg-1 raised temperature at 0.049 degrees C X s-1. Hence the sensitivity of the EHL mode of heat dissipation is directly proportional to the rate of heat absorption and to the rate of rise in body temperature. These data contradict the notion that mammals have control over whole-body heat exchange only (i.e., thermoregulation) but instead indicate that the EHL system is highly responsive to the rate of heat absorption (i.e., temperature regulation).

scholarly journals Raising Power Loss Equalizing Degree of Coil Array by Convex Quadratic Optimization Commutation for Magnetic Levitation Planar Motors

2018 ◽  
Vol 9 (1) ◽  
pp. 79 ◽  
Author(s):  
Shengguo Zhang ◽  
Jingtao Huang ◽  
Jingxian Yang
Keyword(s):  
Power Loss ◽  
Magnetic Levitation ◽  
Quadratic Function ◽  
Quadratic Optimization ◽  
Electromagnetic Forces ◽  
Loss Distribution ◽  
Coil Array ◽  
Boundary Constraints ◽  
Convex Quadratic Optimization ◽  
Global Power

This paper proposes a convex quadratic optimization commutation method to raise the equalization degree of power loss distribution of coil array for magnetic levitation planar motors. Starting with the modeling of electromagnetic forces/torques and commutation of coil array, the global power loss and the local power losses of coil array are analyzed, and the power loss equalizing degree is defined to evaluate the power loss distribution of coil array being commutated dynamically. Then, in consideration of the fact that the global power loss is the quadratic function of commutated coil currents, the convex quadratic function optimization with equality constraint and boundary constraints is applied to commutate the coil array, and the power loss equalizing degree is raised by decreasing the boundary constraints of optimization. Taking the magnetically levitated planar motor under investigation as examples and using quadprog routine in Matlab Optimization Toolbox, which is a dedicated quadratic optimization routine, it is verified that the power loss equalizing the degree of coil array is raised gradually and the power loss distribution of coil array becomes more uniform along with decrease of the boundary constraints. The convex quadratic optimization commutation is verified experimentally on a constructed multi-dimension force/torque measurement platform. Using the convex quadratic optimization commutation can not only improve the power loss distribution of coil array of magnetically levitated planar motors, but also make it possible to select lower capacity power amplifiers to produce the identical desired electromagnetic forces and torques.

scholarly journals Pemodelan Faktor Risiko Penyakit Campak pada Balita di Provinsi DKI Jakarta

2020 ◽  
Vol 9 (1) ◽  
pp. 1-11
Author(s):  
Ayu Annisa Rahmah ◽  
Itasia Dina Sulvianti ◽  
Cici Suhaeni ◽  
Bimandra Adiputra Djaafara
Keyword(s):  
Spatial Heterogeneity ◽  
Weighting Function ◽  
Immunization Coverage ◽  
Multiple Linear Regression Model ◽  
Spatial Location ◽  
Gaussian Kernel ◽  
Annual Rainfall ◽  
Explanatory Variables ◽  
The Difference ◽  
Gwr Model

Measles is one of the infectious caused by virus. The disease is easily transmitted and has become one of the main causes of child mortality especially toddlers. In 2016, Jakarta experienced the highest measles case in the last ten years and found the difference in the number of measles cases in each sub-district of Jakarta. This can be caused by the existence of effect of spatial location i.e. spatial heterogeneity. Geographically weighted regression (GWR) is a method that can be applied to address the presence of spatial heterogeneity in the process of developing the model. In this study, the weighting function used was the Gaussian kernel. The modelling process generated 42 local models at sub-district level. Explanatory variables that influence the incidence rate of measles in toddlers (Y) significantly are the percentage of immunization coverage measles (X1), the total annual rainfall (X4), and the percentage of the number of toddlers (X5). In this study, the GWR model is better than multiple linear regression model which were indicated by higher value of and smaller value of AIC.

scholarly journals Research on the Difference Mechanism of High Voltage Circuit Breaker’s Opening/Closing Coil Current

2021 ◽  
Vol 261 ◽  
pp. 01014
Author(s):  
Yi Su ◽  
Yufeng Lu ◽  
Lei Zhang ◽  
Xiajin Rao
Keyword(s):  
High Voltage ◽  
Circuit Breaker ◽  
Structural Difference ◽  
Circuit Breakers ◽  
Coil Current ◽  
Factors Affecting ◽  
The Operating Mechanism ◽  
The Difference ◽  
Protection And Control ◽  
And Control

High voltage circuit breakers are important protection and control equipment for the power grid. The defects and faults of the circuit breaker seriously affect the safety and stability of the power system. As the key component of the operating mechanism of the circuit breaker, the opening/closing coils contain a large amount of information about the operating status of the mechanism. In order to investigate the cause of the difference in the current waveforms, this paper analyzes the factors affecting the circuit breaker opening/closing coil current based on the actual high voltage circuit breaker, and distinguishes the characteristics of the current caused by the environmental difference and Structural difference. At the same time, the characteristics of coil current changes under four different types of mechanism defects are analyzed. These results lay the foundation for status evaluation of high voltage circuit breakers based on opening/closing coil current.

scholarly journals Method for Assessing Heat Loss in A District Heating Network with A Focus on the State of Insulation and Actual Demand for Useful Energy

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4505 ◽  
Author(s):  
Stanislav Chicherin ◽  
Vladislav Mašatin ◽  
Andres Siirde ◽  
Anna Volkova
Keyword(s):  
Heat Loss ◽  
Internal Heat ◽  
District Heating ◽  
The State ◽  
Estimation Methods ◽  
Fourth Generation ◽  
Pricing Rules ◽  
Smart Energy Systems ◽  
Data Driven Approach ◽  
The Difference

The goal of this paper was to evaluate heat loss and the demand of district heating (DH) in the context of the fourth generation DH concept using a data-driven approach. The heat loss profile was calculated with GIS Zulu© (software (8.0.0.7539, Politerm, LLC, St.Petersburg, Russia) using eight various states of insulation, detailed information on thermal conductivity, internal heat transfer coefficient, and geometry of the concrete trench. There is a strong correlation between the heat sold and the average annual outdoor temperatures. The outstanding episodes are extremely rare, and the difference in the overall pattern is elusive. The results of the annual heat production and annual heat loss analyses were compared using three different estimation methods. The new method was the only one that showed a positive effect after the complete modernization of thermal insulation. The actual proportion of heat loss is much higher at 16%, while the actual heat delivery is less than anticipated at 85–86% only. The trend of the normative approach is correct but cannot determine changes in network heat loss due to aging. The method focuses on the effects of the state of insulation and actual supply temperature levels. The transition to smart energy systems includes strategic and progressive energy planning, as well as new pricing rules and tariffs. Thus, the method presented is the first step in the transition towards the fourth generation DH networks.

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