## 5 Laboratory Verification for PMSM Drive
### Results
The current limit is set to 0.4 p.u. (**a**) Using an MPI speed controller. (**b**) Using a PID speed controller. Figure 13: Experiment: The response of the system to a step change in the speed reference. Once the speed is set, the load change step sequence is performed. The speed changes in the following sequence: 0.6 \(\cdot\) 98 % \(\rightarrow\) 0.6 p.u. (about 199.7\(\rightarrow\)203.8 [rad/s]). The load varies in the sequence from 0 to 0.2 p.u. (2.7 A). The current limit is set to 0.4 p.u. (**a**) Using an MPI speed controller. (**b**) Using a PID speed controller. The test results of control systems with the PMSM are summarized in Table 2. These are tests for step changes in the reference speed. The results for the ramp are shown only to confirm that the performance does not degrade with a different shape of the reference value. It should be noted that comparisons were made for equal controller settings in the simulation and experiment. This applies to both PID and MPI speed controller settings. Quality indicators obtained for simulation and experimental tests, for MPI and PID speed controller structures, are compared. Rows one and two show the results for the experimental drive for the MPI structure (row 1) and the PID structure (row 2). The next two rows show the results for the simulation reference system for the MPI structure (row 3) and the PID structure (row 4). The method for determining quality indicators (the first column) differs depending on whether a simulated or real system is studied. For the simulation model, the IAE indicator (7) is used. For real system tests, the values of the quality indices were determined by post-processing the oscilloscope-recorded data, generating a value corresponding to the calculation method used for _IAE_. It can be seen that for both cases (the simulation and the real system), the ratio of MPI to PID quality indicators is comparable. Likewise, in the case of overshoot (column two), the ratio of the overshoot for MPI to the corresponding value for PID in both cases (simulation vs.  
Figure 16: Experiment: The current waveforms of the reference \(q\)-axis (channel 1) and measured \(q\)-axis (channel-2) for the response of the system to a sloped change in the speed setpoint and reaction to a disturbance. Corresponds to the waveforms in Figure 14. (**a**) Using an MPI speed controller. (**b**) Using a PID speed controller. Figure 15: Experiment: The current waveforms of the reference \(q\)-axis (channel 1) and measured \(q\)-axis (channel-2) for the response of the system to a step change in the speed setpoint and reaction to a disturbance. Corresponds to the waveforms in Figure 13. (**a**) Using an MPI speed controller. (**b**) Using a PID speed controller. experiment) is similar. Column three shows the speed drop when the load is introduced in a step at a given test value. This is the minimum speed value (the higher the value, the better) for the speed range being tested, presented as a percentage of that range. You may notice a lower speed drop for the system with MPI. The fourth column shows the settling time when the setpoint is changed. You can see the similarity of the values. Column five shows the recovery time for a step disturbance. A significant advantage of the MPI system can be noticed: the elimination of the speed deviation occurs in about fifty milliseconds, while the system with PID does not manage to reset the deviation within the hundred milliseconds available during the test.