Enhanced Adaptive Disturbance Observer for Sensorless Control of PMSM With Multiharmonics Suppression Characteristics

The inverter nonlinearity and spatial flux harmonics inevitably result in the back electromotive force (BEMF) harmonics in permanent magnet synchronous motor (PMSM), which deteriorates the performance of the model-based sensorless control. To settle the problem, this article proposes an enhanced adaptive disturbance observer by reconstructing the observer structure based on the pre-designed enhanced complex coefficient filter (ECCF). An ECCF with specific harmonic filtering capability based on conventional complex coefficient filter and multi-frequency suppression module is pre-constructed. Based on the reverse design method, the structure of the conventional disturbance observer is reconstructed into the desired ECCF structure. Multi-harmonics can be suppressed without cascading additional filtering networks after the conventional BEMF observers. The sensorless control algorithm studied is verified by the comparative experiments on a 1 kW PMSM platform.