Voltage-Current Hybrid Model Based Extended Flux Observer with Multiple SOGIs for Sensorless IPMSM Drives

To achieve high-performance sensorless control of interior permanent magnet synchronous motor (IPMSM) drives, this paper proposes an extended flux observer by using the current model to modify the voltage model. The current model is set to correct the voltage model through the PI regulator to form closed-loop control. The proposed closed-loop control method effectively suppresses the DC offsets and integral saturation in the voltage model, which greatly improves the stability and accuracy of sensorless control. On this basis, for the 5th and 7th harmonics caused by the inverter nonlinearity, this paper proposes a filter network composed of multiple second-order generalized integrators (Multiple SOGIs), and uses the integral characteristic of the second-order generalized integrator to replace the pure integral of the voltage model. Multiple SOGIs greatly filter out the high-order harmonics in the back electromotive force (EMF) and improve the accuracy of sensorless control. The effectiveness of the proposed scheme is verified on a 2.2kW IPMSM drive platform.