Optimal Approximation Order Analysis of the Phase-Error-Free Discrete-Time Model for Induction Motor High Speed Drive

Induction motors (IMs) have recently been required to run at a higher speed, which is restricted by the switching frequency limitation since discretization phase errors will appear when the fundamental-to-switching frequency ratio (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$f_{e} / f_{s}$</tex>) is high, leading to significant current control performance degradation. Thus, an innovative phase-error-free discrete-time model (PEFD model) was proposed, which models the discretization phase error correctly and can effectively eliminate the current cross-coupling in high <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$f_{e} / f_{s}$</tex> range. However, an accurate PEFD model needs an unacceptable computing load which impedes its application. Thus, this study explores the impact of the approximation accuracy of the PEFD model on control performance and computational burden, with results verified through simulations.