Open AccessTorque optimisation of seven‐phase BLDC machines in normal and degraded modes with constraints on current and voltage
Author(s) -
Vu Duc Tan,
Nguyen Ngac Ky,
Semail Eric,
Santos Moraes Tiago Jose
Publication year - 2019
Publication title -
the journal of engineering
Language(s) - English
Resource type - Journals
ISSN - 2051-3305
DOI - 10.1049/joe.2018.8123
Subject(s) - torque , control theory (sociology) , voltage , current (fluid) , counter electromotive force , computation , computer science , phase (matter) , electromotive force , direct torque control , physics , engineering , control (management) , electrical engineering , induction motor , algorithm , quantum mechanics , artificial intelligence , thermodynamics
This study proposes several easy‐to‐implement control strategies when seven‐phase axial flux brushless DC machines with trapezoidal back electromotive forces operate in normal and faulty modes by taking into account constraints on voltage and current. The constraints are related to the converter and machine design in terms of maximum values of current and voltage. The considered faults are cases in which one or two phases of the machine are open‐circuited. Numerical computations based on analytical formulations are applied to obtain torque‐speed characteristics, including the flux‐weakening operation. The methods determine current references to ensure the torque optimisations while currents and voltages are within their limits. The usefulness of the methods is verified by numerical results.