Induction machine shaft speed estimation using imaginary power

This paper investigates the use of an imaginary power based speed estimation algorithm for induction machines. The algorithm investigated was first proposed by Peng and Fukao in 1994, and has some very desirable characteristics such as insensitivity to knowledge of stator resistance, and does not use pure integrations. However, it has been shown that the algorithm does not operate stably under regeneration conditions, which has been the main reason that it has not seen much application. This paper investigates the reasons behind this instability, and then develops a solution approach.