High dynamic sensorless control for PMSMs based on decoupling adaptive observer

Voltage reference that contains cross-coupling term between the q- and d-axis is commonly utilized as input of sensorless schemes, and this might cause coupling between speed and position estimation and deteriorate system dynamic performance, which is unacceptable in some applications such as electric vehicle and industrial robot. By employing decoupled voltage reference as observer input, this paper proposes a decoupling adaptive observer for permanent magnet synchronous motor (PMSM), with the estimated rotor speed and position regulated by current estimation errors of the q- and d-axis independently and simultaneously. Dynamic performance of the speed and position estimators, which can be treated as two separate Single-Input-Single-Output (SISO) systems, is analyzed based on their transfer functions, and explicit guidelines for observer gains determination are derived. Experimental tests are conducted on a 1.0 kW PMSM testing platform to verify the effectiveness of the proposed sensorless control approach.