| Abstract |
This paper presents simulation software for electric drives including an electrical machine, frequency
converter and its control system. Finite element method (FEM) model of an electrical machine is
coupled with Simulink by an S-function, which provides a functional block performing the FEM
calculation in time stepping procedure. With this software, an induction motor drive with direct torque
control (DTC) is modeled and simulated. The phase currents of the induction motor are determined by
FEM and used for calculating the estimates for stator flux and torque in the DTC inverter. Both stator
flux linkages and electromagnetic torque of the induction motor are also determined from the FEM
solution and compared with the estimated values obtained from a simple flux and torque estimator. In
steady state, the simple estimates and the values calculated by FEM agree very well, but some
difference is detected in transient operation. The results show effects that can be modeled by FEM but
are not covered in the models based on equivalent circuit approach. It is shown that coupling of the
FEM calculation with Simulink gives detailed information about the interaction between the electrical
machine, inverter and control system. Because of this, the software can be used as an advanced tool
for electric drive design. |
