A Fast-Response, No-Overshoot Gas Mass Flow Controller Based on an Optimized MEMS Piezoresistive Differential Pressure Sensor

This study reports the design and implementation of a high-sensitivity MEMS-based differential pressure sensor, engineered for integration into high-performance gas mass flow controllers (MFCs). The sensor adopts an optimized structural configuration that strategically concentrates mechanical stress in the piezoresistive regions, thereby enhancing its sensitivity. Operating over a pressure range of 0–30 kPa, the sensor achieves a sensitivity of 3.04 mV/V/kPa, exceeding the performance of conventional piezoresistive sensors within the same range. Building upon this sensor, an MFC prototype was developed incorporating a refined orifice structure to ensure stable and precise flow regulation across a control range of 0–100 standard liters per minute (SLM). To address control accuracy and dynamic response, an active disturbance rejection control (ADRC) algorithm was implemented, effectively eliminating overshoot during transient operations. The results achieve a full-scale control accuracy of ±0.45% F.S. and a rapid response time of 90 ms, outperforming comparable commercial MFCs, demonstrating the strong potential of MEMS-based pressure sensing technology for use in high-precision flow control systems.