Research on WPT foreign object detection method based on thermal infrared images

Abstract

In this paper, a foreign object detection (FOD) system based on thermal infrared imaging is designed, taking advantage of its benefits, such as strong penetration in extreme weather conditions, high accuracy of non-contact detection, and no side effect on the wireless power transfer (WPT) system. Firstly, theoretical analysis and improvements are made on image processing techniques such as bilinear interpolation, Gaussian filtering, Operational Test Support Unit (Ostu) adaptive binarization, and morphological operations. Next, the processing advantages of the enhanced algorithms are confirmed using the openCV toolbox. Then, the aforementioned image processing techniques are implemented using embedded programming via the STM32 microprocessor, and the system’s foreign object detection capability is also verified by designing experiments for the location and type of foreign object under 5kW power level. Finally, the experimental results show that the WPT foreign object detection system is effective in the case of detecting and locating foreign objects that up to the size of a half yuan coin even an M4 nut, when the sensor is 15 cm away from the foreign object and the maximum viewing angle is within 110°. At this point, the minimum required temperature deviation between foreign object and background is 7°C, as well as the detection processing time is less than 0.5s, which fully satifies the demand for foreign obiect detection in the WPT system.