Dynamic Modes Simulation of Synchronous Motor Vector Control Electric Drive

Abstract

Purpose: The purpose of the work is a comparative assessment of dynamic processes in electric drives with a vector control system for permanent magnets synchronous motors and various methods of stator voltage modulation. To achieve this purpose, a mathematical description of a synchronous motor in a rotating dq coordinate system is given, and a mathematical model of a vector control system is developed. The model of the vector control system takes into account the decoupling of stator current control loops and proposes two options for generating a current reference along the d-axis, ensuring the efficiency of energy conversion processes at rotation speeds below the nominal value, depending on the design of the motor rotor. Algorithms for scalar pulse-width and space-vector modulation of motor stator voltage for a frequency converter with a two-level autonomous voltage inverter are presented. Methods: When developing mathematical models and algorithms, methods from the theory of electric drive and the theory of automatic control have been used. The developed mathematical models and algorithms are implemented in the Matlab Simulink software package. Results: The results of modeling dynamic processes in electric drives (mechanical characteristics, stator currents, stator current total harmonic distortion) are presented, which have shown the performance of the developed models and algorithms. Practical significance: The choice of modulation type does not affect the mechanical characteristics of the electric drive, but does affect the harmonic composition of the stator current. The greatest effect from the use of space-vector modulation algorithms is manifested at reduced values of the frequency of the stator current and partial load torque on the rotor shaft.