Predictive direct torque control with discrete multiple vector voltages and fuzzy hysteresis

This paper presents a predictive direct torque control (PDTC) system with discrete multiple vector voltage (DMVV) and fuzzy hysteresis for a three-phase induction motor. A fuzzy hysteresis controller is proposed to establish a DMVV for estimating both flux and torque errors, which are the membership functions of the fuzzy system. DMVV switching timing ensures that an appropriate voltage vector is sent to the inverter. The difference between conventional switching timing and DMVV is that conventional timing produces a stator voltage vector in a cycle, whereas DMVV produces four stator voltage vectors in a cycle. The proposed DMVV not only reduces the ripples that are generated with sampling errors and delays, but also enhances the stability of the PDTC system. Verilog hardware description language is used to implement the hardware architecture; a field programmable gate array (FPGA) development board is used to verify designed functions. According to the results measured using the FPGA development board, the proposed PDTC with DMVV and fuzzy hysteresis successfully works at an operating frequency of 50 MHz, with a supplied voltage of 1.8 V and a power consumption of 300 mW.