Ultralocal-Model Generalized Integrator Observer Based Current Reconstruction Strategy for Single DC-Link Shunt PMSM Drives

Due to the limitations of the single current shunt sampling topology and the minimum sampling time of the permanent magnet synchronous motor drive system, there is a current sampling dead region (CSDR) at the operation of high modulation index (MI). In order to expand the output voltage range of the inverter and improve the parameter robustness, a phase current reconstruction (PCR) strategy with ultralocal-model-based generalized integral current observer is proposed. The impact of CSDR on the inverter output voltage is analyzed, and the parameter sensitivity of the PCR strategy with the model-based observer is clarified. Based on the constructed ultralocal-model, a generalized integral current observer is designed to realize PCR at the operation of high MI. The stability of the proposed generalized integral current observer is analyzed, and the influence of its characteristic parameters is explained. The proposed strategy has higher reconstruction accuracy and better parameter robustness. The effectiveness of the proposed strategy was verified on the 2.2-kW interior permanent magnet synchronous compressor drive platform.