Design and development of FPGA-based MAGLEV system for a low-speed wind tunnel

Abstract

The present work seeks to develop a magnetic levitation (MAGLEV) system suitable for a low-speed wind tunnel to support light weight models using FPGA controller. The concept of Pulse Width Modulation (PWM) was used to control single degree of freedom. The reference voltage set and the differential voltage from linear Hall Effect sensors (SS 494B) are compared. The duty cycle varies from 0 to 100% based on the position of the object. These sensor outputs were connected to NI 9239 and the output (PWM) was obtained from NI 9472. This output was given to the driver circuit to achieve appropriate action. A MOSFET was used to boost the current required for levitation. A diode was connected in parallel with the electromagnet to avoid reverse current flow. A LabVIEW FPGA program was built in order to generate PWM and finally levitate the object. FPGA-based control is event-based control and provides microsecond delay.