A new tracking method with FPGA chip for ultrasonic welding system
A new feedback control method of using field-programmable gate array (FPGA) chip for ultrasound welding system is appeared in this article. This feedback control circuits of ultrasound welding system consists of microprocessor control unit, signal generator, power amplifier, the feedback of voltage detector and current detector, etc. The experimental results exhibited this feedback control method can effectively and automatically catch frequency and rack a proper frequency for the ultrasound welding system.
Full-bridged MOSFET DC-to-RF inverter for high frequency ultrasonic transducer at 3 MHz
Described is a full-bridged MOSFET DC-to-RF inverter operating at a frequency of 3 MHz for driving a high frequency ultrasonic transducer for cleaning material surfaces. The full-bridged MOSFET DC-to-RF inverter generates an RF power of 60 W with a power conversion efficiency of 79 to 87% at 3 MHz when an ultrasonic transducer with a very low impedance in the order of 1 to 5 ohms is connected to the inverter. The ultrasonic transducer was satisfactorily operated when the ultrasonic transducer was driven from the full-bridged MOSFET DC-to-RF inverter.
Output power and efficiency tradeoff in full-bridged MOSFET power inverter for use at shortwave frequencies
Methods to increase the output power while keeping the power conversion efficiency high are discussed. Examples of the DC-RF MOSFET powers inverter operating at both 2.5 MHz and 3 MHz are presented. Despite the difficulties in designing the full-bridged MOSFET power inverter having the output power enhanced by parallel connection of the MOSFETs operating at shortwave frequencies, the experimental versions were operated with reliability and without any extraordinary temperature rise.<<ETX>>