Research On Resonant Power Supply For Plasma Cleaning And Control Strategy

Plasma cleaning technology,as a new surface treatment technology in manufacturing industry,will gradually become the mainstream treatment means in the field of surface cleaning because of its advantages of environmental protection,harmlessness,high efficiency and drying.In this paper,the plasma cleaning power supply is taken as the research object.The hardware circuit topology of the system,efficient and wide range power regulation strategy,fuzzy PFM control algorithm and adaptive genetic optimization algorithm are mainly studied.This paper analyses the key technology and research progress of plasma cleaning power supply,including discharge reactor,circuit topology and control strategy.Through comparative analysis,"coaxial cylindrical reactor with rotating nozzle" is chosen as the discharge nozzle of plasma cleaner,and "front rectifier filter circuit + phase-shifted full bridge series resonant circuit" is chosen as the main circuit topology of the system.According to the discharge nozzle and main circuit topology,the equivalent model,working sequence and mode are analyzed,and the control strategy of “PSPWM-PFM” hybrid modulation is proposed.The correctness of the control strategy in theory is verified by simulation.According to the determined system architecture,the key circuits of each module of plasma cleaning power supply are analyzed and designed in detail.Considering the requirements of low ripple coefficient and low current peak value,the filter capacitor and rectifier bridge are selected.According to the stress requirement,the parameters of the phase-shifted full-bridge circuit switch tube and the isolation capacitor are designed.The high-frequency resonant transformer is designed based on AP method.With STM32 as the main control core,the fullbridge driving circuit,parameter sampling and protection circuit are designed.Based on UCC28610 power supply control chip,quasi-resonant flyback auxiliary power supply and high precision voltage-reducing power supply are designed.This paper compares and analyses various power regulation strategies,designs the control strategy of PSPWM-PFM hybrid modulation,designs the maximum power tracking algorithm based on the fuzzy PFM to solve the problem that the system is vulnerable to interference and deviates from the resonant frequency point,and builds the model to simulate the hybrid power regulation strategy and the maximum power tracking algorithm of the fuzzy PFM,which verifies the correctness of the theoretical analysis.By comparing the conventional and improved PID algorithm,the adaptive genetic optimization PID parameter adjustment algorithm is designed.The simulation results show that the anti-jamming,steady-state performance and dynamic response speed of the system are significantly improved.In order to realize the above algorithm,the software program of the system is compiled according to the task priority,and the human-computer interaction interface is designed.In this paper,a prototype of plasma cleaning is developed,and the corresponding experimental platform is built.The waveforms of the key circuit points and the sampling accuracy of the control module are tested.The experimental results are in good agreement with expectations.Three kinds of modulation algorithms are tested and compared.The experimental results show that the hybrid modulation algorithm has more advantages in comprehensive effect,its output efficiency is 83.0%~95.7%,the power regulation range is 500W~1000W,and the output power accuracy is 90%~94%.The factors affecting the effect of plasma cleaning are tested and analyzed.The experimental results show that distance is negatively correlated with cleaning effect,setting power is positively correlated with cleaning effect,and glass material is easier to be modified than aluminium material.