Wide-Band Constant-Parameter Voltage-Behind-Reactance Model of Squirrel-Cage Induction Machines

Variable frequency drives are widely utilized in many commercial and industrial applications. Therein, typically, a three-phase squirrel-cage induction machine (IM) is fed from an inverter through a cable. To design and tune such systems, various models of IMs have been proposed in the literature to study the motor-converter interactions and the low-to-high frequency phenomena. This paper presents a wide-band model for the IMs that is valid in the frequency range from DC to ten MHz. The new model is obtained by incorporating the low-mid frequency voltage-behind-reactance model with the universal high-frequency stator and bearing circuit models. The performance of the proposed model is demonstrated using computer simulations and experimental results obtained from a 7.5hp induction motor connected to a drive system through a cable. The new model is demonstrated to accurately predict the common mode (CM) and differential mode (DM) impedances, reflected transient over-voltages, CM currents, and bearing voltages, all representing an advantage over the conventional/existing IM models.