Zero-Speed Sensorless Control Method for IPMSM Drives Using Virtual Voltage Signal Injection Based Full-Order State Observer

The model-based sensorless control method of interior permanent magnet synchronous motor (IPMSM) fails at zero speed due to unobservability. In this paper, a full-order state observer with virtual voltage signal injection is proposed to realize the zero-speed sensorless control under rated-load for IPMSM drives. The local weak observability criterion of motor speed is established by the nonlinear analysis method. On this basis, the virtual voltage signal is injected into the input voltage of the fullorder state observer, which satisfies the local weak observability and ensures the stability at zero speed. The selection method of injection virtual voltage coefficient is obtained by analyzing the relationship between the virtual voltage signal and the position estimation error. Compared with the conventional model-based method, the proposed approach can achieve stable zero-speed sensorless control under rated load without injecting the actual voltage signal, avoiding additional noise and vibration. Whereby, it expands the operational range of traditional model-based methods. Finally, the effectiveness of the proposed method is verified on a 2.2kW sensorless IPMSM drive platform.