The ultrasonic generator, also known as the ultrasonic power supply, is actually a signal generator. It forms a signal of the same frequency as the piezoelectric transducer and drives the transducer to work according to the amplified power, thus producing ultrasonic vibration.

The development of ultrasonic generator:

The rapid development of the ultrasonic generator went through four periods:

The first link: the age of the tube generator;

The second link: Transistor Analog Generator era;

The third link: Switch-type Generator Era (the current mainstream) ;

The fourth link: Digital Generator Era (future development trend) .

Ultrasonic generator classification:

The ultrasonic generator is divided into self-excited circuit and other-excited circuit according to the circuit design.

Self-excited circuit has no signal source, it is oscillation, power amplifier, output transformer and transducer set into one, produce a closed-loop loop, loop in accordance with the strength, phase feedback conditions, a power-amplified oscillator is formed and resonated on the mechanical resonance frequency of the transducer. Due to the large number of load transducers, the self-excited circuit is difficult to achieve resonance effect according to debugging. So now the industrial use of ultrasonic cleaning equipment mostly choose the other excitation circuit of the ultrasonic generator.

The structure of he-excited circuit mainly includes the former stage oscillator (signal source) and the latter stage amplifier (signal amplifier) two aspects. The ultrasonic energy is usually transmitted to the transducer by coupling an output transformer.

1, the signal source part uses CPU as the center of the signal generation and circuit control, usually driven by 12 -15 V voltage, resulting in square wave signal supply signal amplifier circuit. Timing, pulse, sweep frequency and other functions can be achieved by controlling the signal output signal source, select low-voltage control, more reliable.

Signal amplification part amplifies the signal generated by the signal source and outputs it to the Ultrasonic transducer. The output circuit of ultrasonic generator with different circuit is the key factor to determine the efficiency of electro-acoustic conversion.

How to judge the quality of the ultrasonic generator

The quality of the ultrasonic generator can be judged in two ways:

One is to see whether the output power is constant. We all know that when the voltage of an ultrasonic power supply changes. The output power of the ultrasonic power supply will also change, which is reflected in the mechanical vibration of the Ultrasonic transducer from time to time, resulting in uneven cleaning effect. So need smooth output power, according to the power feedback signal corresponding adjustment power amplifier, to promote power amplifier smooth.

Second, to see if the frequency tracking is efficient. When the Ultrasonic transducer stick to the resonant frequency point, it is most efficient and reliable to work. However, the resonant frequency point of the Ultrasonic transducer will change due to assembly and aging, but the change is merely a frequency shift, not a big one. Frequency tracking can control the frequency of the ultrasonic generator to follow the resonant frequency of the Ultrasonic transducer within a specific range. Keep the generator in its best state from start to finish.

Matching of ultrasonic generator and transducer

In the same model of ultrasonic cleaning machine, the ultrasonic generator and transducer paired debugging good cleaning effect on it; paired debugging poor cleaning effect only poor. For the same set of ultrasonic system, if the cleaning effect after a period of time worse, or replaced the vibrating box, should be re-debugging impedance matching circuit.

The impedance matching of the ultrasonic generator needs to solve not only the variable impedance problem, but also the tuning problem, at present, the enterprises mostly base on the experience of ultrasonic engineers, and the matching effect is different.

In a real-world scenario, some manufacturers find that a well-tuned ultrasound in the factory never works for the customer. There are also customers who ask why their cleaning equipment is working well, but the quality of the product cleaning is not stable, there are many factors, the ultrasonic system does not match well to one of the very important factors.

The pair debugging of ultrasonic system is very important for ultrasonic cleaning equipment, so the current manual pair debugging greatly limits the manufacturing efficiency of ultrasonic system and the stability of cleaning equipment.

The development trend of ultrasonic generator in the future

With the rapid development of science and technology in China and the continuous improvement of the industry, ultrasonic technology is still breaking the old new. In the wave of industry digital transformation, all kinds of automatic cleaning equipment are doing digital upgrade to meet the needs of the future digital factory, ultrasonic generator will enter the era of digital generator.

The ultrasonic generators of the future will become simpler, more versatile and more intelligent. There was no need for a professional to do the matching and debugging, and everyone could do it with one click. Compatibility was greatly improved, and a single generator could be used to match various frequencies and power loads. It could be easily connected to a digital network, communicate with cleaning equipment and plant control.

There will be more and more cleaning equipment manufacturers focus on the use of automatic matching function of ultrasonic generator, ultrasonic cleaning industry will be accompanied by the progress of technology to solve the problems.