D15.1 - Estimation of the Electrical Equivalent Circuit Parameters of an Induction Machine at Standstill Using the Recursive Least Squares Algorithm and Optimized Excitation Conditions

The induction machine is the most widely used machine in the field of industrial applications. For sensorless field-oriented control (FOC), an accurate knowledge of the electrical equivalent circuit parameters is of paramount importance to ensure robust and torque-precise operation. This paper presents a method to determine the electrical parameters of the inverse Gamma equivalent circuit using single-phase excitation. A pseudo random binary sequence (PRBS) signal is used as the excitation input. Due to the available degrees of freedom of this signal, an approach for optimizing the excitation parameters based on the machine time constants is proposed. For modeling, a continuous-time model approach is applied, which requires the calculation of derivatives of measured signals for estimation using the recursive least squares method. Since a numerical approach leads to a strong amplification of high-frequency noise components, the derivative calculation is performed using filters with differentiating behavior. Finally, experimental investigations demonstrate the results of applying the method to three machines of different power classes.