Field programmable gate array-based fault-tolerant hysteresis current control for AC machine drives

This study presents a field programmable gate array (FPGA) implementation of a simple fault-tolerant control that ensures continuous operation of hysteresis current controlled AC machine drives under faulty current sensor. The adopted control requires the use of three current sensors and is available for three-phase isolated neutral systems. The third current sensor allows the faulty current sensor detection and isolation based on analytical redundancy that provides residuals with well-defined thresholds. The control is reconfigured in case of faulty current measurement and operation continuity is performed using the remaining two healthy sensors. The main interest of using FPGAs to implement such controllers is the very important reduction of execution time delay in spite of algorithm complexity. As a result, a high sampling frequency can be used and the residual thresholds can be accurately defined even for the experimental set-up. Numerous experimental results are given to illustrate the efficiency of FPGA-based solutions to achieve efficient and reliable fault-tolerant hysteresis current control of AC machine drives.