Frequency tracking system for output signals of ultrasonic power supply based on fuzzy PI control technology

Abstract

The invention discloses a frequency tracking system for output signals of an ultrasonic power supply based on a fuzzy PI control technology, which is composed of a hardware circuit and software programs, wherein the hardware circuit includes a voltage and current sampling circuit, a band-pass filtering circuit, a phase discrimination circuit, an STM32 chip, an IGBT driving circuit and a display screen connected with the STM32 chip, the phase discrimination circuit collects the phase difference between voltage and current and realizes a digital phase-locked loop, the fuzzy PI control technologyis implemented in the form of the software programs, the software programs are executed by the STM32 chip, the main control program includes a system initialization program, a display screen program,a phase difference information capturing program and a PWM frequency control output program, and the PWM frequency control output program includes a PWM output program and a fuzzy PI algorithm program. The frequency tracking system disclosed by the invention can enable the frequency of the output signals of the ultrasonic power supply to change along with the resonant frequency of a transducer, thereby achieving automatic, accurate and fast tracking for the resonant frequency of the transducer.

Description

technical field [0001] The invention relates to an ultrasonic power supply output signal frequency tracking system, in particular to an ultrasonic power supply output signal frequency tracking system based on fuzzy PI control technology, which belongs to the field of electrical technology. Background technique [0002] Ultrasonic power supply is usually called ultrasonic generator or ultrasonic generator. Its function is to convert electrical energy into a high-frequency AC signal that matches the ultrasonic transducer (hereinafter referred to as transducer). [0003] As one of the important products of ultrasonic technology, ultrasonic power supply is widely used in cleaning, medical treatment, welding and other fields. With the rapid development of ultrasonic technology, people have higher and higher requirements for the efficiency, precision and life of ultrasonic power supplies. In order to improve the working efficiency of the ultrasonic power supply, the frequency of ...

AI Technical Summary

Problems solved by technology

However, for industrial high-power ultrasonic power supplies, the transducer generates heat during operation, the load range is large, and the mechanical loss of the transducer is extremely serious due to the working environment, all of which will lead to the inherent resonance frequency drift of the transducer. , in order to greatly improve the production efficiency and service life of the high-power ultrasonic power supply, the high-power ultrasonic power supply must have the function of accurately, quickly and automatically tracking the resonant frequency of the transducer

[0004] Traditional ultrasonic power output signal frequency tracking systems mostly use analog phase-locked loops, but this method has a narrow frequency tracking range, slow response, inflexible control, and cannot track transducers with different frequency characteristics.

[0005] At present, most of the traditional PI algorithms are used to realize automatic frequency tracking through phase difference or current maximum control. However, there are many factors affecting the transducer resonance frequency drift, and the offset is difficult to use accurate mathematical models. Therefore, the classical control theory method cannot meet the high-precision and fast-response requirements of frequency tracking correction

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