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
Ocean waves can directly drive WECs （wave energy converters） to perform two types of motion--reciprocating motion and unidirectional rotary motion. In general, the efficiency of a reciprocating WEC is strongly wave-...Ocean waves can directly drive WECs （wave energy converters） to perform two types of motion--reciprocating motion and unidirectional rotary motion. In general, the efficiency of a reciprocating WEC is strongly wave-frequency dependent, whereas the efficiency of a rotary WEC can be somewhat wave-frequency independent. To date, a huge majority of WEC technologies under development in industry belong to the reciprocating class, and only a few WEC concepts fall in the unidirectional rotary class. In the present work, a wave-driven rotor for unidirectional rotary motion was proposed and characterized. A numerical tool has been developed for characterization of the rotor＇s unidirectional rotary tendency. The tool included a wave model and a drag force model. Simple circular tubes were used as blades in a basic rotor design. This basic design demonstrated strong potential for unidirectional rotary motion at a proper rotor submersion level and under various wave conditions. Two improved designs were yielded from the basic design. In one improved design, the original circular tubes were replaced with cylindrical shells of semicircular cross section as new blades. In another design, the semicircular shells were further modified to become one-way foldable. The two improvements significantly enhanced the rotors＇ unidirectional rotary tendency in waves, which has been verified by numerical simulation. Broad ranges of wave parameters and the submersion level have been numerically explored on the two improved rotor designs in conjunction with dimensional analysis.展开更多
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.
文摘Ocean waves can directly drive WECs （wave energy converters） to perform two types of motion--reciprocating motion and unidirectional rotary motion. In general, the efficiency of a reciprocating WEC is strongly wave-frequency dependent, whereas the efficiency of a rotary WEC can be somewhat wave-frequency independent. To date, a huge majority of WEC technologies under development in industry belong to the reciprocating class, and only a few WEC concepts fall in the unidirectional rotary class. In the present work, a wave-driven rotor for unidirectional rotary motion was proposed and characterized. A numerical tool has been developed for characterization of the rotor＇s unidirectional rotary tendency. The tool included a wave model and a drag force model. Simple circular tubes were used as blades in a basic rotor design. This basic design demonstrated strong potential for unidirectional rotary motion at a proper rotor submersion level and under various wave conditions. Two improved designs were yielded from the basic design. In one improved design, the original circular tubes were replaced with cylindrical shells of semicircular cross section as new blades. In another design, the semicircular shells were further modified to become one-way foldable. The two improvements significantly enhanced the rotors＇ unidirectional rotary tendency in waves, which has been verified by numerical simulation. Broad ranges of wave parameters and the submersion level have been numerically explored on the two improved rotor designs in conjunction with dimensional analysis.
