Research On Technology Of Amplifing Power For Ultrasonic Water Treatment

The paper has developed one power amplifier being used for the water treatment drive ultrasonic transducer, it has realized the power amplification being frequency from 18kHz to 30kHz sine waves and the maximum amplitude about 1.5V, maximal adjustable output voltage amplitude is 210V , the maximum power output is 300W.In the first place, paper analyses the control scheme for the switching power amplifier. The paper has taken single-phase bridge inverter circuit as the topology mian circuit , and wave form has carried out analytical comparison on unipolar and bipolar Sinusoidal Pulse Width Modulation (SPWM) , it have found out the relation modulating depth and the Carrier frequency than with component harmonics and voltage modulating the polarity. For improving equivalent switch frequency, improving the quality of exporting wave form, it has chosen unipolar modulate way.The paper has analyzed the characteristic of ultrasonic transducer the relationship of electrics resistor and ultrasonic frequency and single stage LC filter and two stage LC filter, it has tracked the power amplification having chosen the two-stage LC wave filter to the switch combining with changer matching and frequency.The control circuit is required to be simple, robust and easily controlled. The dissertation introduces the TMS320F2812, which is the control core of the electric power harmonics simulator rig with powerful operacing ability and abundant interior resources. By the fact that F2812 built-in 12 bit the dc-to-ac inverter adopt regular sample generates SPWM wave form, it realize to the digital control of switching power transistor.By analyzing the results gained by emulat ion experiment and the actual device experiment, the design scheme is proven to be valid and feasible.