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In DC microgrids (DCmGs), distributed control is becoming a promising framework due to prominent scalability and efficiency. To transmit essential data and information for system control, various communication network topologies and protocols have been employed in modern DCmGs. However, such communication also exposes the DCmG to unexpected cyber attacks. In this demo, a scalable cyber security testbed is established for conducting hardware-in-the-loop (HIL) exper-iments and comprehensively investigating the security impact on DCmGs. Specifically, the testbed employs a Typhoon HIL 602+ emulator, which is professional in power electronics system emulation, to demonstrate four (12 at most) distributed energy resources (DERs). The communication network is implemented through the self-loop RS-232 interface. Based on the testbed, we systematically investigate the impact of two kinds of typical cyber attacks (i.e., false data injection and replay attacks). Experimental results show that both attacks will deteriorate the point-of-common coupling (PCC) voltages of the DERs and jeopardize the stability of the whole DCmG.

High-speed image acquisition technology has a great significance to improve the effciency of the workpiece surface quality detection, image quality directly affects the final test results. Aiming at the high-speed image acquisition of workpiece surface quality online detection, a workpiece image high-speed online acquisition method was produced. A high-speed online image acquisition sequence was designed. The quantitative relationship between the positioning accuracy in the high speed online image acquisition, motion blur, exposure time and the speed of workpiece was analyzed. The effect between the vibration between transfer mechanism and workpiece was analyzed. Fast trigger was implemented by photoelectric sensor. The accurate positioning was implemented by using the high accuracy time delay module. The motion blur was controlled by reducing the exposure time. A high-speed image acquisition system was designed based on the high-speed image acquisition method. The positioning accuracy was less than 0.1 mm, and the motion blur was less than one pixel.