Heat Dissipation Design Research Articles

Magneto-Thermal Coupling Analysis of an Axially Split Phase Spherical Bearingless Flywheel Machine

The axially-split phase spherical bearingless flywheel machine (ASP-SBFM) operates mostly in fast charging and discharging conditions. The unique topology design and high power density of the ASP-SBFM can lead to complex machine losses and result in high-temperature rise. This article employs magneto-thermal coupling to perform an accurate analysis of the temperature field distribution of the ASP-SBFM. First, as the heat source for machine temperature rise, the ASP-SBFM losses are analyzed in detail. And the theoretical calculation results agree well with the FEA results. Then, the magneto-thermal coupling method is conducted to obtain the accurate temperature distribution of ASP-SBFM, where both natural cooling and high vacuum conditions are considered. The temperature distribution results can provide a reference for machine heat dissipation design, topology optimization, and machine body material selection.

Design and Performance Evaluation of Liquid-Cooled Heat Dissipation Structure for Lithium Battery Module

The current global resource shortage and environmental pollution are becoming increasingly serious, and the development of the new energy vehicle industry has become one of the important issues of the times. In this paper, a nickel–cobalt lithium manganate (NCM) battery for a pure electric vehicle is taken as the research object, a heat dissipation design simulation is carried out using COMSOL software, and a charging heat generation model of the battery pack is established. Combined with the related research on the thermal management technology of the lithium-ion battery, five liquid-cooled temperature control models are designed for thermal management, and their temperature control simulation and effect analysis are carried out. Finally, the performance evaluation system of the thermal management scheme of the lithium-ion battery pack is established based on the analytic network process (ANP) and system dynamics (SD), and the performance of the above five thermal management design models is comprehensively scored and analyzed. The results show that liquid-cooled Models 1 (86.7075) and 5 (89.1055) have the highest overall scores, meeting both the temperature control requirements and the overall thermal management performance, and it is recommended to apply the working condition settings for which they are evaluated as Level I.

The temperature and drift law of hot spots of oil-immersed air-cooled power transformers

This paper carries out three-dimensional transient simulation calculation of hot spot distribution of oil immersed air-cooled transformer under different working conditions based on the finite element method, couples the electromagnetic loss calculation result unit to the temperature field, and takes it as the heat source to establish the mapping relationship of magnetic heat flow multi physical field. Taking SFZ11-30000/110 transformer as an example, the temperature distribution and hotspot position under different working conditions are obtained. By comparing the results of the heating test, the effectiveness of the simulation model is verified. Studies have shown that as the load increases, the position of the hotspot shifts along the wind axis. After the fan is turned on, there is also an axial upward drift of about 3% at the hot spot, which provides a method basis for the winding insulation and heat dissipation design of oil immersed air-cooled power transformer.

Multiport PV-Assisted Electric-Drive-Reconstructed Bidirectional Charger With G2V and V2G/V2L Functions for SRM Drive-Based EV Application

This paper develops a highly-integrated solar-assisted switched reluctance motor (SRM) drive for electric vehicle (EV) applications with electric-drive-reconstructed grid-to-vehicle (G2V) and vehicle-to-grid (V2G)/vehicle-to-load (V2L) functions. The flexible and efficient multimode energy transmission is realized among SRM, battery pack, solar photovoltaic (PV) panels, and AC grid. Under motoring condition, the standard switch modules are employed to implement bipolar current excitation and regenerative braking, which provides great benefits for balanced heat dissipation design and massive production of SRM drives for EVs. Under idle condition, the G2V and V2G/V2L modes can be well-regulated by multiplexing and reconstructing SRM windings and converter topology. The EV can be completely stationary without extra clamping device under the adopted positioning strategy. The battery pack can be charged by the developed bridgeless interleaved boost converter with excellent power factor correction capability, and can also act as discharging source to power the AC/DC grids/loads flexibly cooperated with the PV panels. A proof-of-concept prototype platform is built and the experiments based on a 1 kW three-phase 12/8 SRM are carried out to validate the feasibility of the proposed SRM system.

Research on Motor Rotor Loss of High-Speed Air Compressor in the Application of Hydrogen Fuel Cell Vehicle

As an important component of hydrogen fuel cell vehicles, the air compressor with an air foil bearing rotates at tens of thousands of revolutions per minute. The heat generation concentration problem caused by the high-speed motor loss seriously affects the safe and normal operation of the motor, so it is very important to clarify the loss distribution of the high-speed motor and adopt a targeted loss reduction design for air compressor heat dissipation. In this paper, for an air compressor with a foil bearing with a rated speed of 80,000 rpm, an empirical formula and a three-dimensional transient magnetic field finite element model are used to model and calculate the air friction loss, stator core loss, winding loss and permanent magnet eddy current loss. The accuracy of the analytical calculation method is verified by torque test experiments under different revolutions, and the average simulation accuracy can reach 91.1%. Then, the distribution of the air friction loss, stator core loss, winding loss and eddy current loss of the air compressor motor at different revolutions is obtained by using this method. The results show that the proposed method can effectively calculate the motor rotor loss of a high-speed air compressor with air foil bearing. Although the motor efficiency increases with the increase in motor speed, the absolute value of loss also increases with the increase in motor speed. Stator core loss and air friction loss are the main sources of loss, accounting for 55.64% and 29% of the total motor loss, respectively. The electromagnetic loss of winding, the eddy current and other alloys account for a relatively small proportion, which is 15% in total. The conclusions obtained in this paper can effectively guide calculations of motor loss the motor heat dissipation design of a high-speed air compressor with an air foil bearing.

Innovative heat dissipation design incorporated into a solar photovoltaic thermal (PV/T) air collector: An optimization approach based on 9E analysis

Innovative heat dissipation design incorporated into a solar photovoltaic thermal (PV/T) air collector: An optimization approach based on 9E analysis

Heat dissipation design and optimization of high-power LED lamps

Heat dissipation design and optimization of high-power LED lamps

Mine-used Flameproof Inverter Heat Dissipation Design and Its Performance Analysis

Flameproof inverter for mine-used have a significant warming effect during operation, resulting in reduced reliability and susceptibility to thermal degradation and thermal failure. However, there is a lack of thermal analysis research on the operation mechanism and process evaluation of mining inverters. This paper analyzes the electrical characteristics of internal power devices and calculates the power loss. Secondly, on the basis of comparing the influence of flow rate, structural parameters and installation location on the thermal performance, the forced water cooling + air cooling + natural cooling method is used to optimize the design of the thermal system. Finally, ANSYS Icepak is used to conduct a comprehensive numerical simulation analysis of the internal temperature field characteristics and convective heat transfer characteristics. The simulation verifies the effectiveness of the heat dissipation-based design, and the results show that: the internal components of the mining explosion-proof inverter are not more than 80°C, which is much lower than the value specified in the relevant standards, and it has a good heat dissipation performance, which effectively guarantees the safe, stable and reliable operation of the mining explosion-proof inverter.

Radiative sky cooling in low-medium concentration photovoltaic systems

Low-medium concentration photovoltaics (LM-CPV) can significantly reduce cost by using cheap optical lenses to reduce the area of the solar cell. Recently, radiative sky cooling (RSC) has been demonstrated to be promising for CPV systems. However, in the reported designs of heat dissipation for CPV systems combining the radiative cooler and a heat sink, a simple flat heat sink was used. Therefore, the effect of the radiative heat dissipation was magnified, but the contribution of convection, which accounts for a significant share in the natural working environment of CPV, was inhibited. To give full play to the role of convection, in this paper, a heat dissipation design combining a radiative cooling layer (RCL) and a finned heat sink was proposed. The RCL was laid on the upper surface of the heat sink to enhance heat dissipation for RSC and realize the effects of thermal radiation. The contributions of the RCL in reducing the temperature of the device, heat dissipation, and obtaining a tolerable concentration ratio under different external environments were examined, and the law whereby the cooling effect of the RCL was influenced by the wind speed and ambient temperature was investigated. The results of numerical simulations shown that the proposed passive cooling device could ensure that the temperature of the solar cell did not exceed 71.5 °C at a concentration ratio of 200, and the maximum difference in temperature inside the device was less than 3.8 °C even in extremely harsh environments (wind speed, 0 m/s; ambient temperature, 50 °C), where this satisfies the requirements of heat dissipation in low-medium concentration silicon solar cells. The radiative heat dissipation power per unit area of the RCL was 201 W/m2, far exceeding the convective heat dissipation. Although the area of the RCL only accounted for 7.9 % of the total area of heat dissipation, its radiative ratio of heat dissipation exceeded 15 % of the total heat dissipation and led to a drop in temperature of 1.76 °C. Moreover, the increase in ambient wind speed significantly improved the cooling effect of the device, which could ensure the rise in the temperature of the solar cell relative to the environment to smaller than 5 °C. However, this also diluted the effect of radiative heat dissipation by the RCL. The increase in the ambient temperature significantly improved the ratio of radiative heat dissipation of the RCL to the overall heat dissipation, reaching 20.2 % when the concentration ratio was 100. In all cases, the cooling power per unit area of the RCL was higher than that of convective and conventional radiative heat dissipation. An even better cooling effect could be achieved by further increasing the relative area of the RCL. Finally, we found that the maximum acceptable concentration ratio of the device was approximately linearly related to the size of the heat sink, and using the RCL could enable the device to withstand an additional 10 ∼ 15 multiples of concentration. The work here provides a new technical option for reducing the cost and improving the efficiency of photovoltaic power generation through the systematic exploration of the influence of the RSC on cooling LM-CPV systems.

Conjugate Heat Transfer Analysis and Heat Dissipation Design of Nucleic Acid Detector Instrument

Temperature affects both the stability of nucleic acid detectors and efficiency of DNA amplification. In this study, temperature and flow inside a nucleic acid detector were simulated and the results were used to design vents for the instrument casing. A test platform was constructed to collect experimental temperature data that were used for simulation validation. The experimental and simulation results showed that the temperature error was less than ±3 K. A total of two heat-dissipation schemes were designed based on the simulation and a new instrument casing was fabricated based on the scheme with the best results. Nucleic acid amplification was performed continuously for 120 min using a prototype with the new casing. The temperatures of the monitoring points were stable and the maximum temperature measured only 307.76 K (34.61 °C). Therefore, waste heat was effectively eliminated, which ensured safety of the electronic components and stability of the nucleic acid detection process.

Heat dissipation design of end winding of permanent magnet synchronous motor for electric vehicle

With the continuous improvement of the requirements for motor accuracy, power and weight the heat of the motor is greatly increased while the heat dissipation space is becoming smaller and smaller. In this paper, using potting materials and heat pipes to build an efficient heat path from the coolant jackets to the winding head is to improve the cooling efficiency of the motor. Three motors are manufactured and installed the same casing outside the stator. The end windings of the motor A are directly exposed to air. The end windings of the motor B are filled with potting materials. The end windings of the motor C are installed with heat pipes and filled potting materials in gaps. Under the same heat source and cooling conditions, the final temperature rises of motor A, motor B and motor C are 114 °C, 98.4 °C and 91.6 °C respectively. The experimental results show that the design of improving the heat transfer at the ends of the coil reduces the motor temperature rising by 13.7%–19.6%.

Overview of Integrated Electric Motor Drives: Opportunities and Challenges

Integrated Motor Drives (IMDs) have recently received extensive attention. In electric vehicles (EVs), electric propulsion aircraft, and ship propulsion systems, integrated motors have the great potential to replace traditional motors with the distinct merits of compact size, high power density, high efficiency, and high-cost effectiveness. This paper investigates and reviews integrated motor drives’ development and critical technologies. It not only reveals the research progress of the motor structure, converter, volume optimization, heat dissipation design, and weakening electromagnetic interference of integrated motor drives but also explores in detail the applications of wide-bandgap semiconductors and the integration of LCL filters. In addition, this paper also puts forward the concept of integrated motor drive integration level and establishes a corresponding quantitative method to evaluate IMDs integration level. In the future, integrated wireless motor drives will have a broad scope of research and application. IMDs systems will play an important role in applications requiring high power density, providing solutions to motor system size and heat dissipation problems. This overview will help clarify the opportunities, challenges, and future development of IMDs.

An efficient single-loop method for heat dissipation structure design under random uncertainties with interval distribution parameter

The conventional reliability-based heat dissipation structural design optimization, which fully considers the influence of the random uncertainties in the optimization procedure, can provide an optimum design satisfying the reliability requirements of the heat radiating device. However, in practical heat dissipation design problems, especially in the early stage of structural design which lacks the corresponding experimental data, some crucial distribution parameters of the random uncertainties, may not be determined precisely. This paper establishes a hybrid reliability-based heat dissipation structural design optimization model for the problem with limited information based on a kind of probability-interval hybrid quantification model and proposes a single-loop method to solve this model efficiently. In this optimization model, the interval parameters coupled to the random uncertainties lead to an interval of reliability for each constraint function, thus giving rise to a triple-loop optimization problem. The proposed single-loop method firstly converts the original nested triple-loop optimization model into an equivalent double-loop optimization model through monotonic analysis. Then, the Karush-Kuhn-Tucker (KKT) optimality conditions of the inner loop are enforced to convert the double-loop model into an equivalent single-loop optimization model. Through this treatment, the original triple-loop optimization model can be then solved by a series of design deterministic optimization and the computational demand can be alleviated significantly. The efficiency and accuracy of the proposed single-loop method are verified through several numerical problems.

Optimal design of heat dissipation on low power PCB

ABSRACT With the application of higher and higher power density IC in power driver circuits, an efficient modeling method of thermal design and heat dissipation is desired. In this paper, the printed circuit board (PCB) heat dissipation without heat-sink is discussed. Firstly, the thermal resistance of PCB thermal via array is analytically modeled. Then, the optimal via diameter and number are found in a limited area for minimum thermal resistance. Secondly, the radial temperature distribution is analyzed and a method of designing a proper copper pad for heat dissipation under the design power is posed. Finally, computational fluid dynamics (CFD) simulations are developed to verify the posed model and method.

Heat Flow Field Analysis on Heat Dissipation Features of High-Wattage Power Cabinets

With the rapid development of electronic science and technology, power electronic devices are increasingly efficient, intelligent, small, and multi-functional. To ensure the thermal reliability of these devices, it is particularly important to make a reasonable heat dissipation design. However, there is insufficient research into the precise measurement of the flow field and temperature field within real high-voltage power electronic devices under the heat dissipation state of liquid cooling. To fill the gap, this paper carries out a heat flow field analysis on the heat dissipation features of high-wattage power cabinets. Out of the multiple power electronic device groups in a typical high-wattage power cabinet, a row of power electronic device units was taken as the objects. Then, several power electronic devices were analyzed numerically to establish a thermal model of the power electronic device group. Next, we designed the dissipation structure of the group, obtained the correlation between the flow field uniformity and temperature distribution of power electronic devices, and analyzed the effects of the ambient temperature of the group, the flow rate of cooling air, and other factors on the temperature features of power electronic devices. The proposed thermal model and dissipation system design strategy were proved feasible through experiments.

Analysis of Ventilation and Heat Dissipation Design of Box Type Substation

Analysis of Ventilation and Heat Dissipation Design of Box Type Substation

Single-side micromachined ultra-small thermopile IR detecting pixels for dense-array integration

This paper presents a technology to fabricate ultra-small (100 × 100 μm) thermopile infrared (IR) sensing devices with a novel front-side micromachining process for integration of dense IR detection array. The thermopile IR detection unit is constructed into double-level suspending films, where the IR absorber and n/p-polysilicon thermopile are located at the central-supported upper level and the surrounding-supported lower level, respectively. The separated design for IR absorber and thermopile temperature-detection helps to achieve a high thermocouple fill-factor of 0.9 in terms of the structural area. A single-step wet etching method is proposed to simultaneously release the umbrella-shaped upper-level absorber and the thermal insulation cavity beneath the lower-level thermopile layer. By pre-depositing a polysilicon sacrificial layer, the etching method breakthroughs the restriction of anisotropic over-etch to the single crystalline silicon substrate, thereby maximizing the thermocouple number in the lower-layer film and minimizing the opened area of the etching holes. Finite-element-method simulation results show that the detector with 20 pairs of thermocouples exhibits maximized responsivity than those with more or less pairs of thermocouples. Benefit from the optimized heat dissipation design, the thermopile detection unit in atmospheric environment achieves a high normalized detectivity of 2.1 × 107 cm Hz1/2 W−1, a high responsivity of 52 V W−1 and sound respond time of 1.4 ms. Thanks to the ultra-small unit area, many unites can be densely integrated into IR detection arrays of various scales. As an example, an integrated 4 × 4 IR sensing array is herein fabricated. The 16 integrated pixels demonstrate good consistency in responsivity, with the deviation being less than ±7%. Featuring the tiny-size pixels for dense-array integration and the single-sided micromachining process that is compatible with integrated circuit fabrication, the proposed thermopile IR sensing devices are promising in IR detection applications including consumer-electronic level IR focal plane arrays.

Numerical Analysis and Optimization of Heat Dissipation of Mechanical Automation Equipment Based on Thermal Model

If the internal heat of mechanical automation equipment exceeds or does not reach the thermal equilibrium temperature range, it will adversely affect the operational reliability, environmental protection and production efficiency of the equipment. To tackle the problem, there has been some research on the internal heat dissipation of mechanical automation equipment, but mostly of the existing studies have simply aimed to change the parameters of the cooling system, and little has been done on the loading process and implementation details of the thermal model. Therefore, this paper provides numerical analysis and optimization of the space heat dissipation of mechanical automation equipment based on a thermal model. First, the heat dissipation mechanism of mechanical automation equipment was elaborated in detail, and the structure of the cooling system for mechanical automation equipment was given. Then, a spatial thermal model of mechanical automation equipment was established, and the heat dissipation design process of mechanical automation equipment was given. After that, the differences between the natural convection heat dissipation in large space and that in confined space inside mechanical automation equipment were explored. The experimental results verified the effectiveness of the numerical simulation model proposed in this paper.

A heat dissipation design strategy based on computational fluid dynamics analysis method for shunt active power filter

Aiming at the heat dissipation design problem of shunt active power filter, this paper proposes a computational fluid dynamics (CFD) simulation method of module flow–heat transfer coupling under forced air cooling. The power filter has carried out a detailed heat generation analysis, and given the analysis and simulation results, the heat dissipation system of the parallel active power filter is designed. The experimental results of the compensation performance prove that the designed modular system has an excellent dynamic, steady-state performance, and temperature rise. The experimental results are consistent with the simulation analysis, which demonstrates the effectiveness of the heat dissipation design of the parallel active power filter module proposed in this paper.

Development of LED Package Heat Dissipation Research.

LEDs are widely used in medicine, navigation and landscape lighting. The development of high-power LED is a severe challenge to LED heat dissipation. In this review, packaging technology and packaging structure are reviewed in terms of the thermal performance of LED packaging, and related technologies that promote heat dissipation in LED packaging are introduced. The design of three components to enhance heat dissipation in LED packaging is described: substrate, lens and phosphor layer. By conducting a summary of the technology and structure of the package, the defects of LED package technology and structure are deeply investigated, and the package is prospected. This has reference value for the heat dissipation design of the LED package and helps to improve the design and manufacture of the LED package.