In order to realize automatic tracking drift of resonance frequency of ultrasonic vibration system with high power and high quality factor Q, adaptive fuzzy control was studied with a self-fabricated ultrasonic plasti...In order to realize automatic tracking drift of resonance frequency of ultrasonic vibration system with high power and high quality factor Q, adaptive fuzzy control was studied with a self-fabricated ultrasonic plastic welding machine. At first, relations between amplitude of vibration and frequency as well as main loop current and amplitude of vibration were analyzed. From this analysis, we deduced that frequency tracking process of the vibration system can be concluded as an optimizing problem of one dimensional fluctuant extremum of main loop current in vibration system. Then a method of self-optimizing fuzzy control, used for the realization of automatic frequency tracking in vibration system, is presented on the basis of serf-optimizing adaptive control approach and fuzzy control approach. The result of experiments shows that the fuzzy self-optimizing method can solve the problem of tracking frequency drift very well. Response time of tracking in the system is less than 50 ms, which basically meets the requirements of frequency tracking in ultrasonic plastic welding machine.展开更多
Variations in the behavior of power supplies caused electrical behavior dependence with environmental conditions. by environmental conditions require accurate characterization of the This paper introduces models to he...Variations in the behavior of power supplies caused electrical behavior dependence with environmental conditions. by environmental conditions require accurate characterization of the This paper introduces models to help predict relative humidity （Rtt） and other environmental factors influence on sensitive circuitry in power electronic systems. The resistivity and permittivity of an insulator have been modeled using different water contents i.e. RH, such model also included the mechanical properties of the design. An application example of a high power density, high voltage DC-DC converter is used to verify the results.展开更多
基金Sponsored by the Natural Science Foundation of Shanghai Education Committee(Grant No.05LZ13)Shanghai Leading Academic Discipline Project(Grant No. P1303)Shanghai Elitist Project(Grant No.04YQHB126)
文摘In order to realize automatic tracking drift of resonance frequency of ultrasonic vibration system with high power and high quality factor Q, adaptive fuzzy control was studied with a self-fabricated ultrasonic plastic welding machine. At first, relations between amplitude of vibration and frequency as well as main loop current and amplitude of vibration were analyzed. From this analysis, we deduced that frequency tracking process of the vibration system can be concluded as an optimizing problem of one dimensional fluctuant extremum of main loop current in vibration system. Then a method of self-optimizing fuzzy control, used for the realization of automatic frequency tracking in vibration system, is presented on the basis of serf-optimizing adaptive control approach and fuzzy control approach. The result of experiments shows that the fuzzy self-optimizing method can solve the problem of tracking frequency drift very well. Response time of tracking in the system is less than 50 ms, which basically meets the requirements of frequency tracking in ultrasonic plastic welding machine.
文摘Variations in the behavior of power supplies caused electrical behavior dependence with environmental conditions. by environmental conditions require accurate characterization of the This paper introduces models to help predict relative humidity （Rtt） and other environmental factors influence on sensitive circuitry in power electronic systems. The resistivity and permittivity of an insulator have been modeled using different water contents i.e. RH, such model also included the mechanical properties of the design. An application example of a high power density, high voltage DC-DC converter is used to verify the results.
