Sensorless Predictive Current Control of a Permanent Magnet Synchronous Motor Powered by a Three-Level Inverter

Permanent magnet synchronous motors and their relevant control techniques have become more and more prevalent in electric vehicle driving applications because of their outstanding performance. This paper studies a simple and effective sensorless scheme based on a current observer for a permanent magnet synchronous motor powered by a three-level inverter, which avoids the injection of a high-frequency signal and the observation of back-electromotive force. In this way, a current observer is constructed to observe d–q-axes currents by relying on an extended-current model. Thereafter, the position and speed of the machine can be extracted from two PI controllers associated with the d–q-axes current-tracking errors. Meanwhile, it takes into account the model predictive current control with neutral-point voltage balance to maintain the stability of the three-level inverter system. In general, this scheme realizes sensorless operation in a full-speed domain and is no longer limited by the types of inverter and method used.