The vector control method is known as one of the best methods in controlling the torque and the speed of the induction motors. The vector control separates motor current into field and torque producing components. The torque is proportional to the product of these two perpendicular components and they can be treated separately. Among the various types of the vector control method, R.F.O is more convenient [1]. All of the single-phase induction motors have two unequal main and auxiliary windings. So they can be considered as unbalanced two phase induction motors. Inventing a method for controlling single-phase or unbalanced induction motors has many advantages. In some application (such as military or astronomy) the controlling system must be fault tolerant [2]-[7]. Furthermore in some low power applications using single phase induction motors is more economical [8]-[10]. In this paper a new method for the vector control of singlephase induction motor is presented. The vector control is based on the R.F.O method that was adapted for singlephase induction machine [11], [12]. Estimation of parameters of induction motor like speed has very usages like, regulate of controllers automatically and discern of fault in motor. Estimation of speed parameter by sensor involves high cost and low reliability. In recent years, the Kalman filter algorithm has been used for the parameter estimation of an induction motor, or for the speed estimation of a synchronous and an induction motor [13]-[17]. Kalman
filter filters the input noises and measured noises according to a nonlinear model of induction motor. The basic drive configuration being studied in this paper is presented in Fig. 1. This configuration is indicated for high-performance applications and provides power-factor control and the possibility of operation in regenerating mode.