Education of the republic of uzbekistan tashkent state technical university named after islam karimov

Fig. 1. Structure of ultrasonic electronic generator. 
Possible changes in the operating frequency of the system and its quality factor lead to the 
fact that the master controlled oscillator-1 provides frequency tuning in the frequency range from 

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Mechanical Engineering
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18.0 to 20.1 kHz with a step of no more than 2 Hz. The tuning range is determined by the 
displacement of the resonant frequency of the ultrasonic emitter due to its heating during 
operation. The small discreteness of the frequency tuning step is due to the high quality factor of 
the ultrasonic emitter and, accordingly, the small width of the amplitude-frequency characteristic 
of the emitter, of the order of 50 Hz. 
Power inverter-2, which is a bridge or half-bridge converter operating in switching mode, 
provides pulse excitation of the matching circuit transformer-choke-3. 
Power supply of the emitter with a voltage close to sinusoidal when using emitters with a 
bending-vibrating disk is an important point, since the presence of extraneous harmonics in the 
power signal provokes the excitation of parasitic oscillation modes in the emitter. , reducing the 
efficiency of the emitter in the fundamental mode. 
Voltage regulator - 4 provides the ability to adjust the supply voltage of the power inverter 
- 2, which allows you to adjust the power of ultrasonic exposure in the range from 0 to 100%. 
The block 5 of feedback elements outputs feedback signals used by the generator 
frequency control system and the ultrasonic vibration amplitude control system to maintain the 
resonant mode of operation of the emitter and stabilize the vibration amplitude of its emitting 
surface, respectively. 
Control unit - 7 - the central block of the electronic generator, ensuring the coordinated 
functioning of all systems and blocks of the electronic generator. In fact, this is a microprocessor 
system running under the control of a special program. 
During the operation of the electronic generator, several systems operate simultaneously: 
scanning the frequency range and searching for the resonant frequency of the emitter; 
preservation of the resonant mode of operation of the emitter and the electronic generator; 
detection of "breakdowns" in the generator and its repeated restart; control and stabilization of 
the power of ultrasonic radiation; detection of low-frequency modulations (modulation of the 
audio range) and emergency shutdown of the electronic generator [6-14].