Predictive Direct Torque Control Chip with a Fuzzy Controller for Induction Motor

This paper proposes a modified predictive direct torque control (PDTC) application specific integrated circuit (ASIC) with a fuzzy controller for eliminating sampling and calculating delay times in a motor drive. A finite delay time not only degrades the control quality but also increases both torque and flux ripples in the motor drive. The proposed PDTC ASIC with a fuzzy controller (fuzzy PDTC) not only calculates the stator's magnetic flux and torque by detecting the three-phase current, three-phase voltage, and rotor speed, but also eliminates large ripples in the torque and flux by using the fuzzy controller and performing predictive calculations. In particular, by using a predictive scheme and fuzzy controller, the proposed ASIC can reduce the ripples in the torque by reducing the time delays in the hysteresis controller. Verilog Hardware Description Language was used to implement the hardware architecture, and the ASIC was fabricated in a TSMC 0.18 μm process by employing a cell-based design method. The use of predictive calculations and fuzzy control not only eases the ripple problem faced in the traditional direct torque control but also increases the control system stability by reducing the time delays in the hysteresis controller. Measurements show that the proposed fuzzy PDTC ASIC has a test coverage of 96.03%, fault coverage of 95.06%, chip area of 1.81 mm × 1.81 mm, and power consumption of 296 mW at an operating frequency of 50 MHz and a supply voltage of 1.8 V.