What’s ultrasonic generator?

What’s ultrasonic generator?

The ultrasonic generator is essentially a power generator that generates a sinusoidal signal of a certain frequency, which is conducted to the transducer through a cable coupling line, and the transducer converts the electrical signal provided by the ultrasonic generator into mechanical vibration.

An ultrasonic generator is a device for generating and supplying ultrasonic energy to an ultrasonic transducer to operate at a resonant frequency. According to its excitation mode, it can be divided into two types: one is  separately excited and the other is self-excited. 

separately excited  ultrasonic generator mainly consists of two parts: the front stage is a signal generator, the latter stage is a power amplifier, and the ultrasonic energy is generally applied to the transducer through the output transformer coupling. The self-excited ultrasonic generator connects the signal generator, power amplifier, output transformer and transducer into a whole, forming a closed loop circuit, so that the whole generator generates sufficient power through amplitude and phase feedback to make the transducer The resonance is automatically maintained at the mechanical resonance frequency.

The working process is as follows:

a signal generator is used to generate a pulse signal of a specific frequency, which is the mechanical resonance frequency of the transducer itself. Generally, the ultrasonic frequency used in the ultrasonic device is 25 kHz to 100 kHz. The power amplifier must be power amplified and then passed through an impedance matching circuit to help the transducer convert the electrical signal into mechanical vibration efficiently. The existence of the feedback circuit not only ensures that the transducer always works in a suitable frequency range, but also keeps the generator in an optimal state and also ensures the safety of the circuit.

The perfect ultrasonic generator should also have feedback links, mainly providing feedback signals in two aspects:

The first is to provide an output power signal. When the supply voltage changes. The output power of the generator will also change, which is reflected in the transducer is the mechanical vibration suddenly large and small.

The second is to provide a frequency tracking signal. When the transducer operates at the resonant frequency point, it has the highest efficiency and the most stable operation, and the resonant frequency point of the transducer changes due to assembly reasons and work aging.

The development of ultrasonic generators has the following trends:

Deepening the research on the mathematical model of processing objects provides a favorable theoretical basis for the design of closed-loop control schemes.

Strengthen the research on closed-loop control of automatic frequency tracking, combined with modern control theory, using adaptive fuzzy control, self-seeking optimal control and other programs to achieve more convenient and more effective control methods, improve generator stability, reliability and automation. degree.

Using modern tools and means, we will develop an automatic frequency tracking system with microcontroller, DSP and other control cores.