Research on Design and Control Strategy of Coating Plasma Power Supply
1. Research Background and Significance
The coating plasma power supply plays a crucial role in Plasma Enhanced Chemical Vapor Deposition (PECVD) technology, which is widely used to produce high-performance thin-film materials such as semiconductors, optical coatings, and protective films. The performance of the plasma power supply directly affects the quality and efficiency of the coating process. Therefore, researching high-stability and high-efficiency coating plasma power supplies and their control strategies is of great significance.
2. Analysis of Coating Plasma Power Supply System Scheme
Plasma Coating Process and Load Characteristics: The plasma coating process requires the power supply to provide stable high-frequency and high-power output to maintain stable plasma discharge. The load characteristics of the plasma generator are complex, typically exhibiting non-linear and time-varying properties.
Overall Power Supply Scheme Design: The power supply system usually includes a rectifier circuit, Power Factor Correction (PFC) circuit, DC chopper circuit, and full-bridge inverter circuit. These circuits work together to achieve high-efficiency energy conversion and stable output.
3. Main Circuit Working Modes and Control Strategies
Boost PFC Circuit: Used to improve the power factor of the power supply and reduce harmonic pollution. Its control strategy includes digital peak current control, which can enhance system stability and response speed through optimized control algorithms (such as fruit fly optimization algorithms).
Buck Amplitude Modulation Circuit: Used to regulate the amplitude of the output voltage, ensuring that the plasma generator receives stable energy input under different working conditions.
Full-Bridge Inverter Circuit: Converts DC to high-frequency AC to drive the plasma generator. Its control strategy includes PAM-PWM hybrid control, which optimizes plasma discharge characteristics by dynamically adjusting frequency and pulse width.
4. Hardware Circuit Design
Power Module: Includes rectifier filter circuits, cascaded Buck-Boost circuits, and full-bridge inverter circuits. The design of these circuits needs to consider high efficiency, high power density, and high reliability.
Control Module: Based on MCU or DSP control modules, which realize precise control of the power supply system. Key circuits include drive circuits, sampling circuits, and communication circuits.
5. Control Strategy Research and Software Design
Overall Control Strategy: Combining the characteristics of Boost PFC, Buck chopper, and full-bridge inverter circuits, a multi-mode switching control strategy is designed. The control precision of the system is further improved through Particle Swarm Optimization (PSO) of the PID controller.
Control Software Design: A dual-processor architecture (such as STM32 and DSP) is used to implement complex control algorithms and human-machine interaction functions. Software design includes FLASH data management, communication modules, and human-machine interaction interfaces.
6. Experiments and Results Analysis
Key Circuit Testing: Tests and optimizations were conducted on the front-end circuits of the power module, full-bridge inverter circuit, and signal sampling circuit. Experimental results show that the optimized control strategy can effectively improve the stability and efficiency of the power supply.
Coating Process Experiments: Experiments verified the impact of power supply power and output frequency on coating effects. Experimental results indicate that the optimized power supply system can significantly improve the quality and uniformity of the coating.
Related Research Advances
In high-power plasma arc systems, a PWM rectifier plus BUCK chopper circuit is used as the main circuit of the power supply system. By designing the main circuit parameters and control loops, the power supply has strong resistance to load disturbances during steady-state operation. This design has been verified in both simulation and experiments, providing a reference for the design of high-power plasma power supplies.
Additionally, in the research of plasma power supplies for material surface modification, a frequency self-adaptive regulation algorithm based on energy density has been proposed. By optimizing the control strategy, the load adaptability and energy utilization efficiency of the power supply have been improved.
Future Outlook
Future research will focus on further optimizing the control strategies of power supplies to enhance their intelligence and adaptability. Meanwhile, with the continuous emergence of new materials and processes, plasma power supply technology will find applications in more fields, driving the development of related industries.
