Papers by Keyword: Thermal Model

Abstract: The aim of this paper is to analyze the SiC MOSFETs behavior under short circuit tests (SCT). In particular, the activity is focused on a deep evaluation of short circuit dynamic by dedicated laboratory measurements conducted at different conditions supported and compared by means of a robust physical model developed by Finite Element Approach.

Abstract: In laser processing of surfaces, typically to impart some texture or to drill shallow holes, it is necessary to correlate pulse properties (wavelength, power, beam radius and quality, duration) and material properties (reflectivity, melting temperature, conductivity, diffusivity) mainly with the depth of the formed crater. Crater shape is assumed to be paraboloidal and its maximum diameter is assumed to be uniquely related to its depth. An empirical and an analytical model are suggested to this end. The former entails construction of Artificial Neural Networks from experimental measurements, whilst the latter entails modification of established models from literature. Both types of models are exemplified in this paper drawing on data from available literature.

Abstract: The heat generation during friction stir welding process influences the material flow, microstructure, and mechanical properties of the friction stir welded plates. This paper proposes a model for predicting heat generation and heat flux during the friction stir welding of AA 6061 aluminium alloy. The heat generation as a function of temperature, heat flux at the shoulder as a function of temperature, radius of shoulder and rotational speed and heat flux at the pin as function of temperature, radius of shoulder and rotational speed have been discussed. It shows that heat generation is inversely proportional to temperature, the heat flux at the shoulder and pin are directly proportional to radius of shoulder and rotational speed and inversely proportional to temperature.

Abstract: This paper proposes a sensorless procedure to estimate the induction motor speed and the dependable heat contents of the stator and rotor sides. The proposed procedure is based on the electrical models of a three phase Induction Motor (IM). The motor electrical models for normal and abnormal will be discussed and a technique is introduced for accommodating frequency dependent skin effect of the rotor resistance using a simple proposed speed estimation algorithm. The electrical models are customized from the positive and negative sequence networks. The speed detection is based on the rotor parameters slip dependent. The models are then used to analyze different operating conditions of the motor. Two thermal motor protection schemes are suggested. The first scheme is dependent on the stator side while the other scheme is developed for rotor side. The Matlab software is used for this purpose to emulate efficiently the proposed estimation procedures through a complete motor modeling which is fed from the power grid. Finally, the results provide the motor performance characteristics which involve current, torque, speed and stator/rotor temperature versus time for numerous operating conditions. It is concluded that the proposed sensorless procedure is efficient to protect the induction motors against abnormal starting as well as the overheating on either stator or rotor sides. Also, the proposed sensorless estimation for speed and temperature is reliable for submersible motor applications. The proposed schemes can be considered as costless preventive maintenance procedure.Index Terms: induction motor, slip dependent, sensorless, thermal model, abnormal operating conditions.

Abstract: Pure lithium-ion batteries for electric vehicles in the course of the temperature rise, not only directly affect the performance and life of the battery, there is a potential safety hazard. In this paper, a pure electric vehicle with a lithium-ion battery pack with no heatsink, through testing and without thermal simulations with a model feasibility analysis.

Abstract: Establishing a general and precise solar cell temperature model is of crucial importance for photovoltaic system modeling and the loss analysis of output power and conversion efficiency. Based on the complex mechanism of solar cell temperature, this paper studies the steady state estimation model of solar cell temperature. Firstly, based on the approximate linear relationship of air temperature, solar radiation intensity, wind speed and solar cell temperature, the polynomial model of solar cell temperature is established and the unknown parameters of the model are extracted with the differential evolution algorithm. Secondly, Experimental acquisition platform is built to reduce the effects of air humidity solar incidence angle on the PV cell temperature. Finally, it shows that the estimated steady-state model is reliable and it fits better performance than other literature submitted through the experimental comparison.

Abstract: The article provides a mathematical description of the thermal processes in the experimental electrolyzer. We have performed computer simulation and verified the adequacy of the model obtained. All thermal processes occurring in the installation during its operation have been identified. The data are currently being used in the synthesis of automatic control systems (ACS).

Abstract: A dome-covered house is an example of designing sustainable buildings by learning from the optimized biological forms from the nature. This paper presents the solar-thermal model for a transparent dome built above one of the several houses located in Montreal. The incident solar radiation on selected cells, the roof and wall surface are presented. The dome-covered helps to reduce the heating load by 79.3% on January 21^st with annual average reduction of 92.9% and if the house is located in Yellowknife, the annual heating load reduction would be 56.3%.

Abstract: This paper proposes a new method to optimize the control of the heating system of a district in a way that fulfills the thermal regulations and comfort in the whole district from one side and guarantees the minimization of the energy consumption (and bill) from the other side. This new method depends on coupling buildings with different functionalities and needs. A heating plan for the coupled entities will be generated afterwards. This plan makes advantage of the difference in occupation timing of the buildings and has as constraints the thermal comfort of the occupants and the maximum available energy. This heating plan takes into consideration the building inertia to design the supply plan and maintain the constraints.

Abstract: The heat dissipation design is very important for controller chip. But the traditional methods can not get the best results. This paper introduces the basic theory about the heat dissipation design and puts forward an optimized method of the heat sink design. This paper uses the thermodynamic principle and matlab simulation to determine the geometrical size of heat sink which can make the controller chip work on the 50°C environmental temperature and the inner temperature of chip under 150°C. Using this method we can design the heat sink quickly and efficiently, and realize a balance between the performance and cost.