Abstract
This paper presents a new unified analysis of estimate errors by model‐matching phase estimation methods such as rotor‐flux state observers, back EMF state observers, and back EMF disturbance observers, for sensorless drive of permanent magnet synchronous motors. Analytical solutions for estimate errors, whose validity is confirmed by numerical experiments, are rich in universality and applicability. As an example of universality and applicability, a new trajectory‐oriented vector control method is proposed, which can directly realize quasi‐optimal strategy minimizing total losses with no additional computational loads by simply orienting one of the vector‐control coordinates to the associated quasi‐optimal trajectory. The coordinate orientation rule, which is analytically derived, is surprisingly simple. Consequently, the trajectory‐oriented vector control method can be applied to a number of conventional vector control systems using one of the model‐matching phase estimation methods. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 168(1): 52–65, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20801