Frequency Coupling Matrix Model of a Three-Phase Variable Frequency Drive

This article proposes a model for a three-phase variable frequency drive in frequency domain for balanced harmonic condition. The model is represented by a frequency coupling matrix and is obtained through simulations in MATLAB and experimentation on a commercial drive. Two different model approaches, i.e., average model and lookup table-based model are attempted and difference in their performance is investigated. The model is validated for 70 voltage waveforms recorded at different industrial locations. The results obtained from the model match with the time domain simulation results. The proposed model is very fast with respect to the time of execution. A method to obtain the model in presence of grid impedance is proposed and the impact of variation of the grid impedance on the model parameters is also investigated. Further the application of the model is discussed using case studies.