Experimental investigation and thermal modelling of slot cooling improvement for electrical machines

Intensive transport electrification is key to meet the future increasingly stringent emission targets, with legislations spanning all forms of transport including automotive, aerospace, marine and rail. The electrical machine is at the heart of all the electrified transport architectures, and hence improving its performance metrics, being it power density (kW/kg, kW/L), efficiency or cost performance ($/kW) is critical to increase the proliferation of cleaner, greener technologies. Thermal improvements are quite important in improving the performance metrics of electrical machines used for transport, and this research focuses on the aforesaid aspects while keeping a multi-domain perspective. Taking as a case study an existing Interior Permanent Magnet Synchronous Machine used for an EV traction application, firstly thermal models are built and experimentally validated. The thermal models are then used to conduct sensitivity analysis on the constituent elements, from which it is determined that the slot number and the effective slot thermal conductivity are important aspects which merit looking into more detail within this research. By conducting multi-domain studies, including electromagnetic and thermal aspects, the optimal slot number is investigated and experimentally validated, with guidelines provided on the selection of this parameter for temperature reduction for different stator sizes. Subsequently a novel, low-cost, effective way to improve the thermal performance of concentrated-wound electrical machines is proposed by extending a part of the back-iron extension into the slot, with the invention named ‘Back Iron Extension’ (BIE). Comprehensive modeling and experimental validation of BIE is conducted, with a 26.7% peak temperature reduction demonstrated, and general guidelines on its sizing are also provided. The simplicity of the BIE, which requires no additional costly materials and which can be implemented within the lamination punching process make it a strong candidate to be used with the next generation of high power density, high cost-performance electrical machines

Design and Application of Microcontroller-Based Tunnel Construction Environment Monitor

With the country\u27s strong support for infrastructure, tunnel-related projects are also increasing daily. Combined with the current Internet of Things (IoT) technology booming, the realization of intelligent construction has become the mainstream direction of today\u27s tunnel construction. This design is mainly realized by combining IOT communication technology, sensor technology, and microcontroller technology. STM32 microcontroller acts as the system\u27s central processing unit and receives real-time information on gas concentration, smoke concentration, pipe wall pressure, and water level collected by various sensors, then displays the data on the LED display after data processing. When the environmental data exceeds the standard, it will automatically drive and adjust the water pumps and fans and simultaneously move the WiFi module to remotely send the data to the mobile phone APP through the Internet cloud server. When the environmental data exceeds the standard, it automatically drives and adjusts the water pump and fan while moving the WiFi module to remotely send the data to the cell phone APP through the Internet cloud server. After actual testing, the system can meet the design requirements and further improve the safety and convenience of tunnel construction

Generating Visual Scenes from Touch

An emerging line of work has sought to generate plausible imagery from touch. Existing approaches, however, tackle only narrow aspects of the visuo-tactile synthesis problem, and lag significantly behind the quality of cross-modal synthesis methods in other domains. We draw on recent advances in latent diffusion to create a model for synthesizing images from tactile signals (and vice versa) and apply it to a number of visuo-tactile synthesis tasks. Using this model, we significantly outperform prior work on the tactile-driven stylization problem, i.e., manipulating an image to match a touch signal, and we are the first to successfully generate images from touch without additional sources of information about the scene. We also successfully use our model to address two novel synthesis problems: generating images that do not contain the touch sensor or the hand holding it, and estimating an image's shading from its reflectance and touch.Comment: ICCV 2023; Project site: https://fredfyyang.github.io/vision-from-touch

Sensitivity analysis of machine components thermal properties effects on winding temperature

This paper investigates the sensitivity analysis of winding temperature to key parameters in electrical machine thermal design. With a validated 3D thermal model based on an existing 75kW traction machine for an electric vehicle, the methodology of the sensitivity analysis study is conducted and presented. Finally, further research and practical guidelines on reducing the peak temperature of electrical machines are proposed

Equivalent slot thermal conductivity and back-iron extension effects on machine cooling

Back-iron Extension (BIE) is an effective thermal management technique which reduces the winding temperatures by projecting part of the back iron into the center of slot, thereby shortening the heat transfer path between the coil and back iron. Based on an existing concentrated-wound traction motor, this paper investigates the effects of equivalent slot thermal conductivity of coil on the optimal back iron extension geometry and temperature reduction

Coil Design and Optimization of Inductive Power Transfer System for Tram

As a new type of urban transit vehicle, Non-catenary trams using inductive power transmission technology get rid of the traditional overhead catenary. In engineering applications, coils assembled on the different tram bodies have inevitable differences due to the restrictions on the production process and other factors. Research shows tiny differences in self-inductance always lead to system detuning so as to causes an extreme descent of the system power factor. From the perspective of hardware design, the paper analyzes the system architecture and coil configuration for the dynamic charging trams with considering cost, system reliability, etc. Then, for the problem of power factor reduction caused by the differences in the self-inductance of the secondary windings, the article establishes a mathematical model with the maximum power factor as the goal and system parameters as constraints. And a complete system parameters design method is proposed. Finally, the global design and optimization of tram's electromagnetic coupling mechanism parameters are performed using the group method. The simulation result indicates that the method can meet the requirements of system operation and has a higher tolerance to the self-inductance differences of the secondary coils

Using Shallow Platform Drilling Technology to Tap the Reserves of the Below Constructed Area of Fuyu Oilfield: Taking Chengping Block 12 as an Example

The special geographical conditions in the below constructed area of the surface have caused the poor oil-water well condition, incomplete well patterns, difficult measures for tapping potential, and no effective development of reserves, which have affected the comprehensive adjustment of Fuyu oilfield. In order to solve this problem, the shallow large platform horizontal well technology was studied in Fuyu oilfield by taking Chengping 12 reservoir as an example. This technology has been successfully applied under limited ground conditions, and underground reserves have been fully utilized. This study has laid a solid foundation for fuyu oilfield to increase recoverable reserves and achieve stable production during the 12th Five-year plan

Semantic Communications with Explicit Semantic Base for Image Transmission

Semantic communications, aiming at ensuring the successful delivery of the meaning of information, are expected to be one of the potential techniques for the next generation communications. However, the knowledge forming and synchronizing mechanism that enables semantic communication systems to extract and interpret the semantics of information according to the communication intents is still immature. In this paper, we propose a semantic image transmission framework with explicit semantic base (Seb), where Sebs are generated and employed as the knowledge shared between the transmitter and the receiver with flexible granularity. To represent images with Sebs, a novel Seb-based reference image generator is proposed to generate Sebs and then decompose the transmitted images. To further encode/decode the residual information for precise image reconstruction, a Seb-based image encoder/decoder is proposed. The key components of the proposed framework are optimized jointly by end-to-end (E2E) training, where the loss function is dedicated designed to tackle the problem of nondifferentiable operation in Seb-based reference image generator by introducing a gradient approximation mechanism. Extensive experiments show that the proposed framework outperforms state-of-art works by 0.5 - 1.5 dB in peak signal-to-noise ratio (PSNR) w.r.t. different signal-to-noise ratio (SNR)

A Topology-Controlled Photonic Cavity Based on the Near-Conservation of the Valley Degree of Freedom

We demonstrate a novel path to localizing topologically-nontrivial photonic edge modes along their propagation direction. Our approach is based on the near-conservation of the photonic valley degree of freedom associated with valley-polarized edge states. When the edge state is reflected from a judiciously oriented mirror, its optical energy is localized at the mirror surface because of an extended time delay required for valley-index-flipping. The degree of energy localization at the resulting topology-controlled photonic cavity (TCPC) is determined by the valley-flipping time, which is in turn controlled by the geometry of the mirror. Intuitive analytic descriptions of the "leaky" and closed TCPCs are presented, and two specific designs--one for the microwave and the other for the optical spectral ranges--are proposed.Comment: 5 pages, 6 figure

Directed Greybox Fuzzing with Stepwise Constraint Focusing

Dynamic data flow analysis has been widely used to guide greybox fuzzing. However, traditional dynamic data flow analysis tends to go astray in the massive path tracking and requires to process a large volume of data, resulting in low efficiency in reaching the target location. In this paper, we propose a directed greybox fuzzer based on dynamic constraint filtering and focusing (CONFF). First, all path constraints are tracked, and those with high priority are filtered as the next solution targets. Next, focusing on a single path constraint to be satisfied, we obtain its data condition and probe the mapping relationship between it and the input bytes through multi-byte mapping and single-byte mapping. Finally, various mutation strategies are utilized to solve the path constraint currently focused on, and the target location of the program is gradually approached through path selection. The CONFF fuzzer can reach a specific location faster in the target program, thus efficiently triggering the crash. We designed and implemented a prototype of the CONFF fuzzer and evaluated it with the LAVA-1 dataset and some real-world vulnerabilities. The results show that the CONFF fuzzer can reproduce crashes on the LAVA-1 dataset and most of the real-world vulnerabilities. For most vulnerabilities, the CONFF fuzzer reproduced the crashes with significantly reduced time compared to state-of-the-art fuzzers. On average, the CONFF fuzzer was 23.7x faster than the state-of-the-art code coverage-based fuzzer Angora and 27.3x faster than the classical directed greybox fuzzer AFLGo