Design and simulation of ASIC-based system control: application to direct torque control of induction machine

This paper presents a general "top-down" methodology for design and simulation of system control ASIC (application specific integrated circuit) using hardware description languages (HDL). Two languages are used: VHDL (very high speed integrated circuit hardware description language) for ASIC modeling and realization, and SpectreHDL for analog modeling of the control environment. The different models allow the optimization step by step of the final ASIC from the optimization of the control algorithm to the ASIC architecture. Each stage is completed by a functional validation resulting of mixed (analog/digital) simulation. This methodology is applied to direct torque control (DTC) of an induction machine. After describing the DTC principle, algorithm validation and optimization are studied: choices of numerical calculation methods, binary format and type. Then, architecture optimization is developed in order to implement the algorithm. Due to torque regulation accuracy and reduced treatment time, optimized architecture using 32 bits fixed point specific format type has been hardware implemented.