Self-adaptive high-frequency injection based sensorless control for IPMSM and SynRM

An auto-tuning and self-adaptation procedure for high-frequency injection (HFI) based position and speed estimation algorithms in IPMSM and SynRM drives is proposed in this paper. Analytical developments show that the dynamics of the high-frequency tracking loop varies with differential inductances, which in turn depend on the machine operating point due to saturation. On-line estimation and adaptation of the small-signal gain of the loop is proposed here, allowing accurate auto-tuning of the sensorless control scheme, even without any a priori knowledge of the machine parameters. Interesting byproducts of this proposal are the possibility for on-line adaptation of the current controllers and of the injected voltage magnitude, leading to important advantages from the performance, loss and acoustic point-of-view. The theoretical basis of the method will be first introduced and the main concept demonstrated by means of simulations. Implementation has been carried out using the hardware of a standard industrial drive and two 2.2 kW prototype IPMSMs. Experimental test results demonstrate the feasibility and effectiveness of the proposal.