# Time Domain Investigation of Hybrid Intelligent Controllers Fed Five-Phase PMBLDC Motor Drive
## 5 Experiment and Discussions
The waveforms in Figure 15a are taken from the Agilent four-channel DSO (x-3034A model) with a 10:1 probe for measuring line voltages and a 100:1 probe for measuring phase currents, respectively. The first two channels give the line-to-line voltage (V\({}_{\text{ab}}\) and V\({}_{\text{bc}}\)) and the next two channels give the two phase currents (Ia and I\({}_{\text{b}}\)). A 2.4 V peak-to-peak voltage corresponds to a 24 V peak-to-peak voltage in a probe ratio of 10:1. Similarly, a 34 mA peak-to-peak current with a 100:1 probe ratio gives a 3.4 A phase current. Figure 15b-d is taken from the Tektronix two-channel 60 MHz DSO (TBS1062). The hall signals received from the motor are connected to an F to V (Frequency to Voltage) converter to obtain an analog voltage corresponding to the frequency of the hall element. The F to V converter is calibrated for a 560 mV output voltage at a speed of 1400 rpm. The frequency of the hall element is directly proportional to the speed of the BLDC motor; with a different controller algorithm, the speed responses for different controllers in terms of step load variation are taken and depicted in Figure 15b-d.  
As seen in Figure 15b, the motor is started with no load and, after 2.7 s, the motor reaches a steady state speed of 1400 rpm (560 mV) with an overshoot of 37.8% (900 mV). At a time of 4.6 s, a load of 1.5 nm is applied. It is observed that the motor speed immediately drops after applying the load and, due to PI controller action, the steady state speed is restored in 7 s. Figure 15c shows the steady state and transient performance of the fuzzy controller. The motor initially starts with zero load and subsequently reaches a steady state speed of 1400 rpm in less than 1 s. A step load of 1.5 nm is applied at 3.8 s. The controller reverts the motor back to its rated speed in less than a second. When compared to the PI controller, the overshoot percentage is negligible. The motor attains a steady-state speed quicker compared to the PI controller. The transient and steady state response of the adaptive hybrid fuzzy-PI controller is shown in Figure 15d, showing that the motor starts at no load and reaches a speed of 1400 rpm in less than 1.6 s. At 2.4 s, a step load disturbance of 1.5 nm is applied, and it is observed that the controller reaches a rated speed of 1400 rpm in less than two seconds. There are five hall sensors mounted on the rotor with a 36\({}^{\circ}\) magnetic angle or 72\({}^{\circ}\) electrical angle to alter the rotor position of the five-phase PMBLDC motor. Figure 16a gives the phase displacement of two-hall sensor pulses at a speed of 941 rpm. The total  
Figure 16: Overshoot Transient behavior with different controllers (Experimental). (**a**) 72 deg hall displacement at 941.1 rpm. (**b**) Overshoot with PI Controller. (**c**) Overshoot with Fuzzy Controller. (**d**) Overshoot with Fuzzy-PI Controller. time period for one pulse is 31.88 ms or 15 divisions. We can see that the time displacement between the two-hall pulses is three divisions, as it corresponds to a 72\({}^{\circ}\) displacement between the hall sensor pulses. Figure 16 b-d present the overshoot responses for the three controllers, namely, PL, fuzzy, and fuzzy-PI. To measure the overshoot response, the machine is started with no load and waveforms are captured until the machine attains a steady state speed (1400 rpm). In Figure 16b, it can be observed that the response oscillates between 616 mV and 512 mV before attaining its steady state value of 560 mV. These oscillations are taken as the overshoot of the response. It accounts for a \(\pm\) 37.8% oscillation from the steady state value. Similar analyses of overshoot with fuzzy and fuzzy-PI are shown in Figures 16c and 16d, respectively.