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Added scan for MPP in both directions, invert starting direction each time, dynamic dAngleMax #9

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Added scan for MPP in both directions, invert starting direction each time, dynamic dAngleMax #9

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3f80bf2
Scan in forward and reverse directions, invert order each time
ilario Jul 21, 2017
102f188
Fixes
ilario Jul 24, 2017
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88 changes: 66 additions & 22 deletions mppTracker.py
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Original file line number Diff line number Diff line change
Expand Up @@ -337,7 +337,10 @@ def weAreDone(sm):
# setup complete. the real mppTracker begins here

# for curve exploration
dAngleMax = 25 #[degrees] (plus and minus)
dAngleMax = dAngleMaxLimit = 25 #[degrees] (plus and minus)
dAngleMinLimit = 3
scannedPointsMinLimit = 5
previousScanStartDirection = -1

while True:
exploring = 0
Expand All @@ -354,7 +357,9 @@ def weAreDone(sm):
if t_run > args.t_total:
weAreDone(sm)
toc = time.time() - tic

myPrint("Stabilized power at Mpp:", file=sys.stderr, flush=True)
myPrint(i*v*1000,"mW @",v,"V", file=sys.stderr, flush=True)

myPrint("Exploring for new Mpp...", file=sys.stderr, flush=True)
exploring = 1
i_explore = numpy.array(i)
Expand All @@ -363,10 +368,24 @@ def weAreDone(sm):
dAngle = 0
angleMpp = numpy.rad2deg(numpy.arctan(i/v*Voc/Isc))
v_set = Vmpp
switched = False
myPrint("Walking up in voltage...", file=sys.stderr, flush=True)
while dAngle < dAngleMax:
v_set = v_set + dV
scanDirection = previousScanStartDirection = previousScanStartDirection * -1
myPrint("Walking {direction} in voltage for starting scan...".format(direction="up" if scanDirection == 1 else "down"), file=sys.stderr, flush=True)
while -dAngleMax < dAngle < dAngleMax:
v_set = v_set + dV * scanDirection
sm.write(':source:voltage {0:0.4f}'.format(v_set))
[v, i, tx, status] = sm.query_ascii_values('READ?')
i = i*polarity
t_run = tx-t0
myPrint('{:1d},{:.4e},{:.4e},{:.4e}'.format(exploring,t_run,v,i), flush=True)
if t_run > args.t_total:
weAreDone(sm)
dAngle = numpy.rad2deg(numpy.arctan(i/v*Voc/Isc)) - angleMpp
myPrint("{limit} exploration voltage limit reached.".format(limit="Upper" if scanDirection == 1 else "Lower"), file=sys.stderr, flush=True)
scanDirection = scanDirection * -1
scannedPoints = 0
myPrint("Scanning walking {direction} in voltage...".format(direction="up" if scanDirection == 1 else "down"), file=sys.stderr, flush=True)
while scannedPoints < scannedPointsMinLimit or -dAngleMax < dAngle < dAngleMax:
v_set = v_set + dV * scanDirection
sm.write(':source:voltage {0:0.4f}'.format(v_set))
[v, i, tx, status] = sm.query_ascii_values('READ?')
i = i*polarity
Expand All @@ -377,35 +396,60 @@ def weAreDone(sm):
i_explore = numpy.append(i_explore, i)
v_explore = numpy.append(v_explore, v)
dAngle = numpy.rad2deg(numpy.arctan(i/v*Voc/Isc)) - angleMpp
if (dAngle < -dAngleMax) and not switched:
myPrint("Upper exploration voltage limit reached.", file=sys.stderr, flush=True)
myPrint("Walking down in voltage...", file=sys.stderr, flush=True)
switched = True
dV = dV * -1 # switch our voltage walking direction (only once)

myPrint("Lower exploration voltage limit reached.", file=sys.stderr, flush=True)

scannedPoints += 1
# find the powers for the values we just explored
p_explore = v_explore*i_explore
maxIndexFirstScan = numpy.argmax(p_explore)
VmppFirstScan = v_explore[maxIndexFirstScan]
ImppFirstScan = i_explore[maxIndexFirstScan]
angleMppFirstScan = numpy.rad2deg(numpy.arctan(ImppFirstScan/VmppFirstScan*Voc/Isc))
myPrint("{limit} exploration voltage limit reached.".format(limit="Upper" if scanDirection == 1 else "Lower"), file=sys.stderr, flush=True)
myPrint("Voltage for Mpp in {direction} scan found at {:.4e} V".format(VmppFirstScan, direction="forward" if scanDirection == 1 else "reverse"), file=sys.stderr, flush=True)
i_explore = numpy.array(i)
v_explore = numpy.array(v)
scannedPoints = 0
scanDirection = scanDirection * -1
myPrint("Scanning walking {direction} in voltage...".format(direction="up" if scanDirection == 1 else "down"), file=sys.stderr, flush=True)
while scannedPoints < scannedPointsMinLimit or -dAngleMax < dAngle < dAngleMax:
v_set = v_set + dV * scanDirection
sm.write(':source:voltage {0:0.4f}'.format(v_set))
[v, i, tx, status] = sm.query_ascii_values('READ?')
i = i*polarity
t_run = tx-t0
myPrint('{:1d},{:.4e},{:.4e},{:.4e}'.format(exploring,t_run,v,i), flush=True)
if t_run > args.t_total:
weAreDone(sm)
i_explore = numpy.append(i_explore, i)
v_explore = numpy.append(v_explore, v)
dAngle = numpy.rad2deg(numpy.arctan(i/v*Voc/Isc)) - angleMpp
scannedPoints += 1
# find the powers for the values we just explored
p_explore = v_explore*i_explore
maxIndex = numpy.argmax(p_explore)
Vmpp = v_explore[maxIndex]
maxIndexSecondScan = numpy.argmax(p_explore)
VmppSecondScan = v_explore[maxIndexSecondScan]
ImppSecondScan = i_explore[maxIndexSecondScan]
angleMppSecondScan = numpy.rad2deg(numpy.arctan(ImppSecondScan/VmppSecondScan*Voc/Isc))
myPrint("{limit} exploration voltage limit reached.".format(limit="Upper" if scanDirection == 1 else "Lower"), file=sys.stderr, flush=True)
myPrint("Voltage for Mpp in {direction} scan found at {:.4e} V".format(VmppSecondScan, direction="forward" if scanDirection == 1 else "reverse"), file=sys.stderr, flush=True)

myPrint("New Mpp found:", file=sys.stderr, flush=True)
myPrint(p_explore[maxIndex]*1000,"mW @",Vmpp,"V", file=sys.stderr, flush=True)
Vmpp = (VmppFirstScan + VmppSecondScan) / 2
myPrint("New Mpp found at {:.4e} V:".format(Vmpp), file=sys.stderr, flush=True)

mppAngleVariation = max(abs(angleMpp - angleMppFirstScan), abs(angleMpp - angleMppSecondScan))
dAngleMax = min(mppAngleVariation + dAngleMinLimit, dAngleMaxLimit)
# now let's walk back to our new Vmpp
dV = dV * -1
v_set = v_set + dV
scanDirection = scanDirection * -1
v_set = v_set + dV * scanDirection
myPrint("Walking back to Mpp...", file=sys.stderr, flush=True)
while v_set < Vmpp:
while not Vmpp - dV <= v_set <= Vmpp + dV:
sm.write(':source:voltage {0:0.4f}'.format(v_set))
[v, i, tx, status] = sm.query_ascii_values('READ?')
i = i*polarity
t_run = tx-t0
myPrint('{:1d},{:.4e},{:.4e},{:.4e}'.format(exploring,t_run,v,i), flush=True)
if t_run > args.t_total:
weAreDone(sm)
v_set = v_set + dV
v_set = v_set + dV * scanDirection
sm.write(':source:voltage {0:0.4f}'.format(Vmpp))
myPrint("Mpp reached.", file=sys.stderr, flush=True)