High-Frequency Square-Wave Voltage Injection Based Parameter Identification of Three-Phase PMSM Drives Fed by CHB Inverters

This paper proposes a high-frequency (HF) square-wave voltage injection method to identify the parameters for three-phase permanent-magnet synchronous motor (PMSM) drives fed by cascaded H-bridge (CHB) inverters. The key is to identify the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$dq-\text{axis}$</tex> inductances independently. In the proposed method, the one module of each phase in the CHB inverter is specifically configured to inject HF square-wave voltages, while the remaining modules are maintained for reference voltage modulation. Furthermore, effective compensation measures are implemented to address the harmonic issues arising from the injection of HF square-wave voltages, the amplitude attenuation caused by filters, and the impact of the inherent nonlinear characteristics of CHB inverters on parameter identification. Simulation results are given to validate effectiveness of the proposed parameter identification method.