A new stator voltage error-based MRAS model for field-oriented controlled induction motor speed estimation without using voltage transducers

A sensorless speed estimation method for performing the indirect field-oriented control (IFOC) of induction motors (IMs) is presented in the current research. The method uses the stator voltage as state variable but eliminates the voltage transducers. Traditional MRAS methods use two sets of equations to estimate the motor speed. However, the proposed system utilizes the q-axis current regulator proportional-integral (PI) control output(V-sq*) in the reference model as a new Model Reference Adaptive System (MRAS) technique and compares this value with the estimated voltage ((V) over cap (sq)) in an adaptive model. The method calculates the steady-state q-axis stator voltage in adaptive model, so, the calculation burden in the estimation loop is significantly reduced. Choosing the q-axis stator voltage as state variable removes requirement of the rotor parameters in calculations, and therefore, the system becomes resistant to the alteration in rotor parameters. Furthermore, the mentioned special calculation ensures the elimination of the need for flux estimation, so the speed estimation technique becomes resistant to integral and derivative calculation-based problems. The MATLAB/Simulink simulation results and experiments under various operation conditions verifies the effectiveness of the studied technique.