A globally exponentially stable position observer for interior permanent magnet synchronous motors
For control engineers, this solves a long-standing open problem in motor position estimation with guaranteed stability.
The paper presents the first globally exponentially convergent position observer for interior permanent magnet synchronous motors, assuming limited saliency, with experimental validation showing high performance at standstill and high speeds.
The design of a position observer for the interior permanent magnet synchronous motor is a challenging problem that, in spite of many research efforts, remained open for a long time. In this paper we present the first globally exponentially convergent solution to it, assuming that the saliency is not too large. As expected in all observer tasks, a persistency of excitation condition is imposed. Conditions on the operation of the motor, under which it is verified, are given. In particular, it is shown that at rotor standstill---when the system is not observable---it is possible to inject a probing signal to enforce the persistent excitation condition. {The high performance of the proposed observer, in standstill and high speed regions, is verified by extensive series of test-runs on an experimental setup.