The increasing demands on safety, emission and fuel consumption require more accurate control models of micro internal combustion swing engine （MICSE）. The objective of this paper is to investigate the constant spee...The increasing demands on safety, emission and fuel consumption require more accurate control models of micro internal combustion swing engine （MICSE）. The objective of this paper is to investigate the constant speed control models of four-stroke MICSE The operation principle of the four-stroke MICSE is presented based on the description of MICSE prototype. A two-level Petri net based hybrid mode/ is proposed to mode/ the four-stroke MICSE engine cycle. The Petri net subsystem at the upper level controls and synchronizes the four Petri net subsystems at the lower level. The continuous sub-models, including breathing dynamics of intake manifold, thermodynamics of the chamber and dynamics of the torque generation, are investigated and integrated with the discrete model in MATLAB Simulink. Through the comparison of experimental data and simulated DC voltage output, it is demonstrated that the hybrid model is valid for the four-stroke MICSE system. A nonlinear model is obtained from the cycle average data via the regression method, and it is linearized around a given nominal equilibrium point for the controller design. The feedback controller of the spark timing and valve duration timing is designed with a sequential loop closing design approach. The simulation of the sequential loop closure control design applied to the hybrid model is implemented in MATLAB. The simulation results show that the system is able to reach its desired operating point within 0.2 s, and the designed controller shows good MICSE engine performance with a constant speed. This paper presents the constant speed control models of four-stroke MICSE and carries out the simulation tests, the models and the simulation results can be used for further study on the precision control of four-stroke MICSE.展开更多
The traditional large electroslag remelting furnaces have many shortages,such as high short-network impedance and inductance,long maintenance time for electrode replacement,low stiffness of driveline,and low control a...The traditional large electroslag remelting furnaces have many shortages,such as high short-network impedance and inductance,long maintenance time for electrode replacement,low stiffness of driveline,and low control accuracy of remelting speed.The present research was aimed to solve these problems through structure modification and constant remelting speed control for a 120-t electroslag remelting(ESR) furnace.Based on the technique of three-phase double electrodes in series,the short-network system and the structure of the 120-t ESR furnace were improved;and a continuous feeding system for the self-consumption electrode was proposed.A selfdesigned fully hydraulic driveline system with three degrees of freedom was successfully applied to the 120-t ESR furnace.An electrode auto-replacement system and the S-style speed-control curve of electrode-feeding system were designed on the basis of the soft measurement/sensing model on the remaining electrode length so as to obtain a high accuracy control system for constant remelting speed.The experiment products showed good surface quality and cross-sectional results,indicating good system control,and verifying the effectiveness of the structure modification of the furnace.展开更多
In general,Variable-Speed Constant Frequency (VSCF)Wind generation system is controlled by stator voltage orientation method which based on the mathematic model of VSCF Wind generation system and discussed the control...In general,Variable-Speed Constant Frequency (VSCF)Wind generation system is controlled by stator voltage orientation method which based on the mathematic model of VSCF Wind generation system and discussed the control strategy.Present the whole dynamic control model of variable-speed wind generator system in MATLAB/ Simulink,and the simulation results confirm the validity and effectiveness of the proposed control strategy.展开更多
For offshore hydraulic drive wind turbines,the problems of unsatisfactory speed control and low efficiency at low wind speeds are targeted.A low-speed high-torque radial piston pump is designed to replace the traditio...For offshore hydraulic drive wind turbines,the problems of unsatisfactory speed control and low efficiency at low wind speeds are targeted.A low-speed high-torque radial piston pump is designed to replace the traditional fixed pump with a particular focus on its low-speed performance.The pump is characterized by small internal leakage at low wind speeds and high volumetric efficiency,which is beneficial to improve the power generation efficiency of the system.A new linear control method based on the PID algorithm and feedforward compensation was proposed to obtain the constant speed output control of variable motor at low wind speed.With the model for wind turbine and fixed pump-variable motor main drive system,the system was simulated and experimentally proved to verify the feasibility and anti-interference performance of the system control method at low wind speeds.A promising outcome was obtained on the response characteristics of system power and efficiency at low wind speeds.This can be a powerful technical support for the normal ustility of hydraulic drive wind turbines.展开更多
基金Supported by National Natural Science Foundation of China(Grant No.51475422)Science Fund for Creative Research Groups of National Natural Science Foundation of China(Grant No.51221004)
文摘The increasing demands on safety, emission and fuel consumption require more accurate control models of micro internal combustion swing engine （MICSE）. The objective of this paper is to investigate the constant speed control models of four-stroke MICSE The operation principle of the four-stroke MICSE is presented based on the description of MICSE prototype. A two-level Petri net based hybrid mode/ is proposed to mode/ the four-stroke MICSE engine cycle. The Petri net subsystem at the upper level controls and synchronizes the four Petri net subsystems at the lower level. The continuous sub-models, including breathing dynamics of intake manifold, thermodynamics of the chamber and dynamics of the torque generation, are investigated and integrated with the discrete model in MATLAB Simulink. Through the comparison of experimental data and simulated DC voltage output, it is demonstrated that the hybrid model is valid for the four-stroke MICSE system. A nonlinear model is obtained from the cycle average data via the regression method, and it is linearized around a given nominal equilibrium point for the controller design. The feedback controller of the spark timing and valve duration timing is designed with a sequential loop closing design approach. The simulation of the sequential loop closure control design applied to the hybrid model is implemented in MATLAB. The simulation results show that the system is able to reach its desired operating point within 0.2 s, and the designed controller shows good MICSE engine performance with a constant speed. This paper presents the constant speed control models of four-stroke MICSE and carries out the simulation tests, the models and the simulation results can be used for further study on the precision control of four-stroke MICSE.
基金financially supported by the National Science and Technology Major Project of the Eleventh Five-Year Plan of China(2009ZX04006-032)
文摘The traditional large electroslag remelting furnaces have many shortages,such as high short-network impedance and inductance,long maintenance time for electrode replacement,low stiffness of driveline,and low control accuracy of remelting speed.The present research was aimed to solve these problems through structure modification and constant remelting speed control for a 120-t electroslag remelting(ESR) furnace.Based on the technique of three-phase double electrodes in series,the short-network system and the structure of the 120-t ESR furnace were improved;and a continuous feeding system for the self-consumption electrode was proposed.A selfdesigned fully hydraulic driveline system with three degrees of freedom was successfully applied to the 120-t ESR furnace.An electrode auto-replacement system and the S-style speed-control curve of electrode-feeding system were designed on the basis of the soft measurement/sensing model on the remaining electrode length so as to obtain a high accuracy control system for constant remelting speed.The experiment products showed good surface quality and cross-sectional results,indicating good system control,and verifying the effectiveness of the structure modification of the furnace.
文摘In general,Variable-Speed Constant Frequency (VSCF)Wind generation system is controlled by stator voltage orientation method which based on the mathematic model of VSCF Wind generation system and discussed the control strategy.Present the whole dynamic control model of variable-speed wind generator system in MATLAB/ Simulink,and the simulation results confirm the validity and effectiveness of the proposed control strategy.
基金supported by Chongqing Natural Science Foundation(cstc2019jcyj⁃msxm2000),Chongqing University of Science and Technology Graduate Science and Technology Innovation Project(JXXY201901)。
文摘For offshore hydraulic drive wind turbines,the problems of unsatisfactory speed control and low efficiency at low wind speeds are targeted.A low-speed high-torque radial piston pump is designed to replace the traditional fixed pump with a particular focus on its low-speed performance.The pump is characterized by small internal leakage at low wind speeds and high volumetric efficiency,which is beneficial to improve the power generation efficiency of the system.A new linear control method based on the PID algorithm and feedforward compensation was proposed to obtain the constant speed output control of variable motor at low wind speed.With the model for wind turbine and fixed pump-variable motor main drive system,the system was simulated and experimentally proved to verify the feasibility and anti-interference performance of the system control method at low wind speeds.A promising outcome was obtained on the response characteristics of system power and efficiency at low wind speeds.This can be a powerful technical support for the normal ustility of hydraulic drive wind turbines.
