When the comparison between the simulation results and the experimental results was made, some
problems show up. One of them was an overshoot in both the d current and the q current during the current
control loop test. Based on the assumption of parameter incorrectness, some parameter adjustment was tried
to get a desirable performance, Rs was doubled and Lσ was tripled. With the new parameters used, the
overshoot problem was basically overcome. But it still can’t be said that the incorrectness of the parameters
is exactly the reason for the overshoot, which is just one of the potential causes. The parameter adjustment
changed the control coefficients in the PI regulators, Ki and Kp, and compensated for the differences
between the simulations and the experiments. The other problem is that during the speed control loop test
the speed response has a small overshoot and a longer rise time, compared with the results of the simulation.
This is probably caused by some practical factors, such as the measured speed with noises and incorrect
machine parameters, which will lead to wrong calculation of some critical variables in the vector control.
Certainly, some small differences between experiments and simulations are tolerable, with these practical
factors concerned.