Design of Cooling Water Temperature Control System for Microwave Plasma Chemical Vapor Deposition Equipment

In order to realize the automatic regulation of cooling water temperature during the preparation of diamond film by microwave plasma chemical vapor deposition (MPCVD) equipment, a cooling water temperature control system based on STM32F103 was designed. With STM32F103 as the main control chip and stepper motor as the executive mechanism, the system has designed the flow signal acquisition circuit, 485 communication circuit, stepper motor drive circuit and other hardware circuits, and adopted the fuzzy PID control algorithm to solve the nonlinear and hysteresis problems in cooling water temperature control. The results show that the system can realize the automatic regulation of cooling water temperature during the operation of MPCVD equipment, with small overshoot, fast response speed and good temperature control effect.