The Design Of High-stability Microwave Power Supply

This thesis discusses the design and tests of the high-stability microwave power supply system with Internal Model Control(IMC),illustrating the differences between the PI controller and PID controller which is designed by the IMC principle for this system.It emphasizes on the working principle of magnetron,the modeling of the controlled process,the design of IMC system and the hardware and software design of the whole microwave power supply system.Inside the microwave power supply system base on magnetron,The traditional PID controller can hardly get satisfactory control result,because of the object's large time lag,the all kinds of immeasurable disorders are ubiquitous and hard to control,and the system component is nonlinear and variable.IMC is a kind of powerful design,analyses and predict tool and a new-type control strategy that the controller is designed on the basis of process mathematics model.The advantage of IMC is what can sum up PID control,Smith predict control,the determinacy linear optimum square feedback control and many kinds of prediction control under the same framework.IMC is a control method based on process model.IMC has simplicity of design principle and parameter alignment and good characters of track adjustability and robust.In order to create the model of controlled process for the nonlinear microwave power supply system,the modeling method based on the principle of Hammerstien parameter model,and the nonlinear controlled process is divided into two parts.There are nonlinear static model and linear dynamic model.Then,the Internal Model Controller is designed and analyzed in MATLAB/Simulink.In order to design a microwave power supply which is suitable for the deposition of diamond film.Built the hardware platform of microwave power supply based on ATmega16 MCU,and tested to improve the stability of output microwave power.The experimental results show that the system with IMC has good performance of anti-interference and small steady-error,and can achieve the goal which to improve the output power stability.In this thesis,a complete reference scheme is proposed for the controller,software and hardware in microwave power supply system.I believe that through the continuous improvement of the system,microwave power supply system with stable output microwave power will be obtained.