Generalized INFORM Method for Low-Speed Position Sensorless Control of PMSM Using Single Current Sampling

In AC variable frequency drive systems, Permanent Magnet Synchronous Machines (PMSMs) are highly favored for their remarkable efficiency, high power density, and compact mechanical structure. Position sensorless control of PMSMs offers notable advantages in enhancing reliability and reducing cost. At the same time, high precision current sensors are expensive, and the use of single current sampling can further reduce costs. However, the reliability of position sensorless control, particularly at low speeds, is impacted by the distortion of applied voltage due to the phase shift of unmeasurable regions, which in turn leads to the failure of position observation. In order to solve the problem of combining single current sampling with position sensorless control, this paper proposes the Generalized Indirect Flux detection by Online Reactance Measurement (GINFORM) method, where the angles of injected voltage vectors can be arbitrarily assigned so that to minimize the negative impact of unmeasurable regions and enhance control reliability. Furthermore, the dynamic PWM modulation method is proposed, where the Field Oriented Control (FOC) execution frequency is increased to further enhance the dynamic performance of the control system. Finally, the effectiveness of the proposed method is verified by experiments on a 2.2kW platform.