Untitled

clearvars

format shortEng

freq = 50;

T = 1/freq;

percents = [5.17 5.5:0.5:10] % corresponding to the measurements

percents = 1×11

     5.1700e+000     5.5000e+000     6.0000e+000     6.5000e+000     7.0000e+000     7.5000e+000     8.0000e+000     8.5000e+000     9.0000e+000     9.5000e+000    10.0000e+000

% experimental RPM measurement with HTI HT522 Tachometer

rpms = [5530, 8900, 12200, 13800, 14500, 15200, 15600, 15800, 16200, 16700, 17700]

rpms = 1×11

     5.5300e+003     8.9000e+003    12.2000e+003    13.8000e+003    14.5000e+003    15.2000e+003    15.6000e+003    15.8000e+003    16.2000e+003    16.7000e+003    17.7000e+003

pulseWidths = percents*T/100

pulseWidths = 1×11

     1.0340e-003     1.1000e-003     1.2000e-003     1.3000e-003     1.4000e-003     1.5000e-003     1.6000e-003     1.7000e-003     1.8000e-003     1.9000e-003     2.0000e-003

fittedPoly = polyfit(pulseWidths, rpms, 3)

fittedPoly = 1×4

    41.5714e+012  -204.6543e+009   336.6311e+006  -169.3421e+003

theoPercents = 5.17:1e-3:10;

theoPulseWidths = theoPercents*T/100

theoPulseWidths = 1×4831

     1.0340e-003     1.0342e-003     1.0344e-003     1.0346e-003     1.0348e-003     1.0350e-003     1.0352e-003     1.0354e-003     1.0356e-003     1.0358e-003     1.0360e-003     1.0362e-003     1.0364e-003     1.0366e-003     1.0368e-003     1.0370e-003     1.0372e-003     1.0374e-003     1.0376e-003     1.0378e-003     1.0380e-003     1.0382e-003     1.0384e-003     1.0386e-003     1.0388e-003     1.0390e-003     1.0392e-003     1.0394e-003     1.0396e-003     1.0398e-003     1.0400e-003     1.0402e-003     1.0404e-003     1.0406e-003     1.0408e-003     1.0410e-003     1.0412e-003     1.0414e-003     1.0416e-003     1.0418e-003     1.0420e-003     1.0422e-003     1.0424e-003     1.0426e-003     1.0428e-003     1.0430e-003     1.0432e-003     1.0434e-003     1.0436e-003     1.0438e-003

theoRpms = polyval(fittedPoly, theoPulseWidths);

figure()

hold on

grid on

grid minor

plot(pulseWidths*1e6, rpms, "x-")

plot(theoPulseWidths*1e6, theoRpms)

xlabel("Pulse Width (\mus)")

ylabel("Motor RPM")

legend("Experimental", "Fitted", Location="southeast")

hold off

figure()

hold on

grid on

grid minor

plot(percents, rpms, "x-")

plot(theoPercents, theoRpms)

xlabel("Pulse Width (%)")

ylabel("Motor RPM")

legend("Experimental", "Fitted", Location="southeast")

hold off

%% Expected RPM at maximum using KV

motorKV = 2300;

appliedvoltage = 7.5;

expectedMaxRPM = motorKV*appliedvoltage

expectedMaxRPM = 
    17.2500e+003