A high-performance digital servo system built on the platform of a field programmable gate array (FPGA),a fully digitized hardware design scheme of a direct torque control (DTC) and a low speed permanent magnet synchr...A high-performance digital servo system built on the platform of a field programmable gate array (FPGA),a fully digitized hardware design scheme of a direct torque control (DTC) and a low speed permanent magnet synchronous motor (PMSM) is proposed. The DTC strategy of PMSM is described with Verilog hardware description language and is employed on-chip FPGA in accordance with the electronic design automation design methodology. Due to large torque ripples in low speed PMSM,the hysteresis controller in a conventional PMSM DTC was replaced by a fuzzy controller. This FPGA scheme integrates the direct torque controller strategy,the time speed measurement algorithm,the fuzzy regulating technique and the space vector pulse width modulation principle. Experimental results indicate the fuzzy controller can provide a controllable speed at 20 r min-1 and torque at 330 N m with satisfactory dynamic and static performance. Furthermore,the results show that this new control strategy decreases the torque ripple drastically and enhances control performance.展开更多
An innovation is conducted on a K190πK rail auto welding machine because of its poor stability in quality of welding joints. A new control system based on a programmable controller is designed to replace the old o...An innovation is conducted on a K190πK rail auto welding machine because of its poor stability in quality of welding joints. A new control system based on a programmable controller is designed to replace the old one. The new control system is of higher accuracy in controlling sequence and good ability in anti disturbance, and is convenient to operate. The comparison tests are carried out. The experimental results show that the quality of welded joints is greatly increased by the improved welding mechine.展开更多
Novel electromagnetic wave modulation by programmable dynamic metasurface promotes the device design freedom,while multibeam antennas have sparked tremendous interest in wireless communications.A programmable coding a...Novel electromagnetic wave modulation by programmable dynamic metasurface promotes the device design freedom,while multibeam antennas have sparked tremendous interest in wireless communications.A programmable coding antenna based on active metasurface elements(AMSEs)is proposed in this study,allowing scanning and state switching of multiple beams in real time.To obtain the planar array phase distribution in quick response,the aperture field superposition and discretization procedures are investigated.Without the need for a massive algorithm or elaborate design,this electronically controlled antenna with integrated radiation and phase-shift functions can flexibly manipulate the scattering state of multiple beams under field-programmable gate array(FPGA)control.Simulation and experimental results show that the multiple directional beams dynamically generated in the metasurface upper half space have good radiation performance,with the main lobe directions closely matching the predesigned angles.This metasurface antenna has great potential for future applications in multitarget radar,satellite navigation,and reconfigurable intelligent metasurfaces.展开更多
基金the Natural Science Foundation of Hubei Province (No.2005ABA301)
文摘A high-performance digital servo system built on the platform of a field programmable gate array (FPGA),a fully digitized hardware design scheme of a direct torque control (DTC) and a low speed permanent magnet synchronous motor (PMSM) is proposed. The DTC strategy of PMSM is described with Verilog hardware description language and is employed on-chip FPGA in accordance with the electronic design automation design methodology. Due to large torque ripples in low speed PMSM,the hysteresis controller in a conventional PMSM DTC was replaced by a fuzzy controller. This FPGA scheme integrates the direct torque controller strategy,the time speed measurement algorithm,the fuzzy regulating technique and the space vector pulse width modulation principle. Experimental results indicate the fuzzy controller can provide a controllable speed at 20 r min-1 and torque at 330 N m with satisfactory dynamic and static performance. Furthermore,the results show that this new control strategy decreases the torque ripple drastically and enhances control performance.
文摘An innovation is conducted on a K190πK rail auto welding machine because of its poor stability in quality of welding joints. A new control system based on a programmable controller is designed to replace the old one. The new control system is of higher accuracy in controlling sequence and good ability in anti disturbance, and is convenient to operate. The comparison tests are carried out. The experimental results show that the quality of welded joints is greatly increased by the improved welding mechine.
文摘Novel electromagnetic wave modulation by programmable dynamic metasurface promotes the device design freedom,while multibeam antennas have sparked tremendous interest in wireless communications.A programmable coding antenna based on active metasurface elements(AMSEs)is proposed in this study,allowing scanning and state switching of multiple beams in real time.To obtain the planar array phase distribution in quick response,the aperture field superposition and discretization procedures are investigated.Without the need for a massive algorithm or elaborate design,this electronically controlled antenna with integrated radiation and phase-shift functions can flexibly manipulate the scattering state of multiple beams under field-programmable gate array(FPGA)control.Simulation and experimental results show that the multiple directional beams dynamically generated in the metasurface upper half space have good radiation performance,with the main lobe directions closely matching the predesigned angles.This metasurface antenna has great potential for future applications in multitarget radar,satellite navigation,and reconfigurable intelligent metasurfaces.
