Performance-Based Linearization Approach for Modeling Induction Motor Drive Loads in Dynamic Simulation

This paper describes a technique to model a vector-controlled induction motor drive in large-scale phasor-level dynamic simulation programs. The performance-based load model is implemented by obtaining the linearized power-voltage and power-frequency transfer functions from test data or from detailed electro-magnetic transient simulation used as a surrogate for test data. Voltage and frequency modulations are performed to obtain the amplitude and phase responses of the detailed vector-controlled drive model for a range of discrete frequencies. The prediction error minimization technique is utilized to generate best-fit analytical transfer function expressions. The electrical interface of the performance-based drive load model is developed to interact with the external system in positive-sequence dynamic simulation programs. The drive model is used to investigate the relative damping effects of drive-connected and direct-connected motors on system voltage and frequency oscillations.