Based on the running characteristics and high energy consumption of air compressors in coal mines,an air pressure PID closed loop control system has been designed in this paper.The system is composed of PLC, converter...Based on the running characteristics and high energy consumption of air compressors in coal mines,an air pressure PID closed loop control system has been designed in this paper.The system is composed of PLC, converter and sensors etc and adopts the control method of converter triple-evaporator which makes air supply"need-based".The designed system has been applied in multiple coal mines and the results show its energy saving is remarkable and potential application is widely.展开更多
The torque-angle characteristics of electric-mechanical converters are important determinants of the quality of electrohydraulic proportional control systems.It is far more difficult for a rotary electric-mechanical c...The torque-angle characteristics of electric-mechanical converters are important determinants of the quality of electrohydraulic proportional control systems.It is far more difficult for a rotary electric-mechanical converter(REMC)to obtain flat torque-angle characteristics than traditional proportional solenoid,greatly influencing the promotion and application of rotary valves for electrohydraulic proportional control systems.A simple and feasible regulation method for the torque-angle characteristics of REMCs based on a hybrid air gap is proposed.The regulation is performed by paralleling an additional axial air gap with the original radial air gap to obtain a flat torque-angle characteristic and increase output torque.For comparison,prototypes of REMCs based on hybrid and radial air gaps were manufactured,and a special test rig was built.The torque-angle characteristics under different excitation currents and step responses were studied by magnetic circuit analysis,finite element simulation,and experimental research.The experimental results were consistent with the theoretical analysis.It was shown that REMCs based on a hybrid air gap can obtain a flat torque-angle characteristic with further optimizing of key structural parameters and also increase output torque.This regulation method provides a new approach for the design of proportional rotary electromechanical converters.展开更多
An explosion-proof dual throttling air-conditioning system was put forward to solve the heat dissipation and internal dewing problems of explosion-proof frequency converter in the underground coal mine. This study inv...An explosion-proof dual throttling air-conditioning system was put forward to solve the heat dissipation and internal dewing problems of explosion-proof frequency converter in the underground coal mine. This study investigated the feasibility and benefits of explosion-proof dual throttling cooling and dehumidification air-conditioning system applied to the explosion-proof frequency converter. The physical model of dual throttling air-conditioning system was established and its performance parameter was described by mathematical method. The design calculation of the system has also been done. The experimental result showed that the system reached the steady state at the refrigeration mode after running 45 min, and the maximum internal temperature of the flame-proof cavity was 31.0 ℃. The system reached the steady state at the dehumidification mode after running 37 min. The maximum internal relative humidity and temperature of the flame-proof cavity were 33.4% and 36.3 ℃, respectively. Therefore, the proposed system had excellent ability of heat dissipation and avoided internal dewing. Compared with water cooling system, it was more energy-saving and economical. The airflow field of dual throttling air-conditioning system was also studied by CFD simulation. It was found that the result of CFD numerical simulation was highly consistent with the experimental data.展开更多
The intermittent nature of wind and solar photovoltaic energy systems leads to the fluctuation of power generated due to the fact that the power output is highly dependent upon local weather conditions, which results ...The intermittent nature of wind and solar photovoltaic energy systems leads to the fluctuation of power generated due to the fact that the power output is highly dependent upon local weather conditions, which results to the load shading issue that led to the voltage and frequency instability. In additional to that, the high proportions of erratic renewable energy sources can lead to erratic frequency changes which affect the grid stability. In order to reduce this effect, the energy storage system is commonly used in most wind-solar energy systems to balance the voltage and frequency instability during load variations. One of the innovative energy storage systems is the compressed air energy storage system (CAES) for wind and solar hybrid energy system and this technology is the key focus in this research study. The aim of this research was to examine the system configuration of the CAES system through modelling and experimental approach with PID controller design for regulating the voltage and frequency under different load conditions. The essential elements and the entire system have been presented in this work as thorough modelling in the MATLAB/Simulink environment for different load conditions. The developed model was tested through an experimental workbench using the developed prototype of the compressed air storage in the Siemens Lab at DeKUT and explored the consequence of the working parameters on the system proficiency and the model accuracy. The performance of the system for the developed prototype of CAES system was validated using results from an experimental workbench with MATLAB/Simulink R2022b simulation. The modeling and experimental results, shows that the frequency fluctuation and voltage drop of the developed CAES system during load variations was governed by the I/P converter using a PID_Compact controller programed in the TIA Portal V17 software and downloaded into PLC S7 1200. Based on these results, the model can be applied as a basis for the performance assessment of the compressed air energy storage system so as to be included in current technology of wind and solar hybrid energy systems.展开更多
为提升特高压换流站消防系统灭火效能,针对目前以水喷雾灭火系统为主的消防设施应对换流变火灾蔓延等恶劣情况存在的不足,提出一种将消防炮增设于阀厅挑檐上的固定式压缩空气泡沫消防系统(compressed air foam fire-fighting system,CA...为提升特高压换流站消防系统灭火效能,针对目前以水喷雾灭火系统为主的消防设施应对换流变火灾蔓延等恶劣情况存在的不足,提出一种将消防炮增设于阀厅挑檐上的固定式压缩空气泡沫消防系统(compressed air foam fire-fighting system,CAFS)。该系统在不占用现有设备空间和检修通道的情况下,利用其灭火能力强、响应速度快、灭火效率高等特点,成倍提升变电站内换流变集中区域的消防能力,保证了最不利情况下换流变火灾消防工作需求。展开更多
文摘Based on the running characteristics and high energy consumption of air compressors in coal mines,an air pressure PID closed loop control system has been designed in this paper.The system is composed of PLC, converter and sensors etc and adopts the control method of converter triple-evaporator which makes air supply"need-based".The designed system has been applied in multiple coal mines and the results show its energy saving is remarkable and potential application is widely.
基金Supported by National Natural Science Foundation of China(Grant No.51975524).
文摘The torque-angle characteristics of electric-mechanical converters are important determinants of the quality of electrohydraulic proportional control systems.It is far more difficult for a rotary electric-mechanical converter(REMC)to obtain flat torque-angle characteristics than traditional proportional solenoid,greatly influencing the promotion and application of rotary valves for electrohydraulic proportional control systems.A simple and feasible regulation method for the torque-angle characteristics of REMCs based on a hybrid air gap is proposed.The regulation is performed by paralleling an additional axial air gap with the original radial air gap to obtain a flat torque-angle characteristic and increase output torque.For comparison,prototypes of REMCs based on hybrid and radial air gaps were manufactured,and a special test rig was built.The torque-angle characteristics under different excitation currents and step responses were studied by magnetic circuit analysis,finite element simulation,and experimental research.The experimental results were consistent with the theoretical analysis.It was shown that REMCs based on a hybrid air gap can obtain a flat torque-angle characteristic with further optimizing of key structural parameters and also increase output torque.This regulation method provides a new approach for the design of proportional rotary electromechanical converters.
基金Supported by the National Basic Research Program of China("973"Program,No.2009CB219907)
文摘An explosion-proof dual throttling air-conditioning system was put forward to solve the heat dissipation and internal dewing problems of explosion-proof frequency converter in the underground coal mine. This study investigated the feasibility and benefits of explosion-proof dual throttling cooling and dehumidification air-conditioning system applied to the explosion-proof frequency converter. The physical model of dual throttling air-conditioning system was established and its performance parameter was described by mathematical method. The design calculation of the system has also been done. The experimental result showed that the system reached the steady state at the refrigeration mode after running 45 min, and the maximum internal temperature of the flame-proof cavity was 31.0 ℃. The system reached the steady state at the dehumidification mode after running 37 min. The maximum internal relative humidity and temperature of the flame-proof cavity were 33.4% and 36.3 ℃, respectively. Therefore, the proposed system had excellent ability of heat dissipation and avoided internal dewing. Compared with water cooling system, it was more energy-saving and economical. The airflow field of dual throttling air-conditioning system was also studied by CFD simulation. It was found that the result of CFD numerical simulation was highly consistent with the experimental data.
文摘The intermittent nature of wind and solar photovoltaic energy systems leads to the fluctuation of power generated due to the fact that the power output is highly dependent upon local weather conditions, which results to the load shading issue that led to the voltage and frequency instability. In additional to that, the high proportions of erratic renewable energy sources can lead to erratic frequency changes which affect the grid stability. In order to reduce this effect, the energy storage system is commonly used in most wind-solar energy systems to balance the voltage and frequency instability during load variations. One of the innovative energy storage systems is the compressed air energy storage system (CAES) for wind and solar hybrid energy system and this technology is the key focus in this research study. The aim of this research was to examine the system configuration of the CAES system through modelling and experimental approach with PID controller design for regulating the voltage and frequency under different load conditions. The essential elements and the entire system have been presented in this work as thorough modelling in the MATLAB/Simulink environment for different load conditions. The developed model was tested through an experimental workbench using the developed prototype of the compressed air storage in the Siemens Lab at DeKUT and explored the consequence of the working parameters on the system proficiency and the model accuracy. The performance of the system for the developed prototype of CAES system was validated using results from an experimental workbench with MATLAB/Simulink R2022b simulation. The modeling and experimental results, shows that the frequency fluctuation and voltage drop of the developed CAES system during load variations was governed by the I/P converter using a PID_Compact controller programed in the TIA Portal V17 software and downloaded into PLC S7 1200. Based on these results, the model can be applied as a basis for the performance assessment of the compressed air energy storage system so as to be included in current technology of wind and solar hybrid energy systems.
文摘为提升特高压换流站消防系统灭火效能,针对目前以水喷雾灭火系统为主的消防设施应对换流变火灾蔓延等恶劣情况存在的不足,提出一种将消防炮增设于阀厅挑檐上的固定式压缩空气泡沫消防系统(compressed air foam fire-fighting system,CAFS)。该系统在不占用现有设备空间和检修通道的情况下,利用其灭火能力强、响应速度快、灭火效率高等特点,成倍提升变电站内换流变集中区域的消防能力,保证了最不利情况下换流变火灾消防工作需求。
