Investigating effects of Delta-Sigma modulation for current measurement on FCS-MPC of IM: Hardware in the loop results

In this paper, the effects of time delays from ΔΣ-ADCs, used for current measurement, on Finite Control Set Model Predictive Control (FCS-MPC) is investigated. For this goal, two FCS-MPC controllers with 50 kHz and 100 kHz sampling rate and one step prediction horizon, were developed and implemented in real time on FPGA in order to control the electrical torque of an Induction Machine (IM). With the help of Hardware In the Loop (HIL) setups, the performance of FCS-MPC with 18 bits and 21 bits ΔΣ-ADC modulation techniques as well as without any ΔΣ-ADC is investigated. Regarding the time delays from ΔΣ-ADCs, the results show higher Total Demand Distortion (TDD) as well as higher RMS of error on electrical torque with increasing time delay i.e. higher output bit-word. On the other hand, the phase currents have less TDD with higher output bit-word.