1500W 28KHZ 40KHZ Signal Ultrasound Cleaning Transducer Generator PCB Circuit Board Power Supply

The significant characteristics of self-excited ultrasonic drive circuit board ultrasonic cleaning are high quality, fast speed, ability to clean areas that cannot be cleaned by ordinary cleaning methods, and easy automation. The traditional ultrasonic power supply is self-excited, with a simple circuit. 然而, the feedback applied to the base of the switch tube is unstable, which means that the switching frequency changes greatly and the output ripple is also large. This article studies the self-excited ultrasonic power supply, which has smaller voltage loss, larger output power, easy adjustment, strong anti-interference ability, and relatively better output waveform compared to the self-excited ultrasonic power supply.

The ultrasonic power supply designed for self-excited ultrasonic drive circuit board has two major functions: frequency tracking and constant power control. The research content of this article is mainly divided into the following parts: The hardware part of the ultrasonic power supply is mainly divided into three parts, one is the main circuit part, feedback control circuit, and matching circuit. The main circuit mainly converts 220V mains power into DC through a rectification and filtering circuit, and then through a BUCK chopper circuit for power regulation. The inverter circuit converts it into AC power and delivers it to the load. The piezoelectric transducer is in a capacitive state, so a matching circuit needs to be added before connecting the load to make the entire ultrasonic power supply resonate with the load, achieving maximum efficiency. By using a closed-loop system to achieve a stable state of the entire system, a feedback control loop is installed in the circuit. Firstly, the sampled current is filtered and true effective value converted through a signal conditioning circuit, and the obtained signal is input into a microcontroller for processing. The maximum current method is used to determine the resonant frequency, which is achieved through frequency sweep.

The self-excited ultrasonic drive circuit board microcontroller outputs control signals to the signal generator to generate PFM waves to control the switching frequency of the inverter circuit and achieve frequency conversion effect; By keeping the load current constant, the output power is kept constant. The microcontroller outputs a control signal to the signal generator to generate PWM to drive the BUCK circuit, achieving constant power. The matching circuit is improved in the traditional case of series inductance, by connecting a capacitor in series for high pass filtering, resulting in a more complete waveform. The software mainly samples signals for frequency calculation, current reading, display, frequency tracking, and power control. The frequency calculation is achieved through the counting method, and the current reading is to read the true RMS signal of AD637. The display part uses LCD1602 to display the sampling frequency and current. By comparing the sampling frequency and resonant frequency, the sampling current and target current are output to control the main circuit. The simulation section uses Matlab for hardware circuit simulation, adjusting the parameters of various relevant components to output the required waveforms for each unit module. Finally, a sine wave with a voltage of 500V and a current of 4A is obtained at the load end, which meets the design requirements.