Deadbeat-direct torque & flux control motor drive over a wide speed, torque and flux operating space using a single control law

Abstract

This paper presents an implementation of deadbeat-direct torque and flux control (DB-DTFC) for AC induction machine drives that demonstrates nearly ideal properties over a wide range of flux and torque operating conditions, including deep field weakening. A key attribute of this DB-DTFC is that the control law is the same over the entire operating space, including steady-state and transient operation at the voltage limits. By comparison, field oriented control at the voltage limit is inherently compromised and requires adjustment of the current control laws. Similarly, PI control-based DTFC becomes oscillatory under voltage limit conditions. This DB-DTFC implementation requires no change to the control law under voltage limit conditions. This paper presents an implementation of DB-DTFC and experimentally demonstrates its performance over a full range of operating conditions, including operation at the voltage limit.