Phases: allow 1p scale-down when the loadpoint never disables (#33214)

Author: andig

core/loadpoint.go

@@ -1438,8 +1438,9 @@ func (lp *Loadpoint) minCharging() error {
 	return lp.setLimit(lp.effectiveMinCurrent())
 }
 
-// pvScalePhases switches phases if necessary and returns number of phases switched to
-func (lp *Loadpoint) pvScalePhases(sitePower, minCurrent, maxCurrent float64) int {
+// pvScalePhases switches phases if necessary and returns number of phases switched to.
+// mayDisable indicates that insufficient surplus can stop charging via the pv disable timer.
+func (lp *Loadpoint) pvScalePhases(sitePower, minCurrent, maxCurrent float64, mayDisable bool) int {
 	phases := lp.GetPhases()
 
 	// observed phase state inconsistency
@@ -1466,8 +1467,9 @@ func (lp *Loadpoint) pvScalePhases(sitePower, minCurrent, maxCurrent float64) in
 		}
 
 		// while charging, scaling down only helps if 1p is sustainable, otherwise it
-		// merely delays the pv disable timer by the phase timer duration
-		useful := !lp.enabled || !lp.charging() || powerToCurrent(availablePower, 1) >= minCurrent
+		// merely delays the pv disable timer by the phase timer duration. Without a
+		// disable to wait for, scaling down is the only way to reduce power (#33208).
+		useful := !lp.enabled || !lp.charging() || !mayDisable || powerToCurrent(availablePower, 1) >= minCurrent
 		if insufficient && !useful {
 			lp.log.DEBUG.Printf("available power %.0fW < %.0fW min 1p threshold, disabling instead of scaling down", availablePower, Voltage*minCurrent)
 		}
@@ -1638,10 +1640,14 @@ func (lp *Loadpoint) pvMaxCurrent(mode api.ChargeMode, sitePower, batteryPower f
 	// push demand to drain battery
 	sitePower -= lp.boostPower(batteryPower)
 
+	// minpv and the battery conditions hold charging at min current, no disable can follow
+	battery := batteryStart || batteryBuffered && lp.charging() || lp.GetBatteryBoost() == boostContinue
+	mayDisable := mode == api.ModePV && !battery
+
 	// switch phases up/down
 	var scaledTo int
 	if lp.hasPhaseSwitching() && lp.phaseSwitchCompleted() {
-		scaledTo = lp.pvScalePhases(sitePower, minCurrent, maxCurrent)
+		scaledTo = lp.pvScalePhases(sitePower, minCurrent, maxCurrent, mayDisable)
 	}
 
 	// calculate target charge current from delta power and actual current
@@ -1659,7 +1665,7 @@ func (lp *Loadpoint) pvMaxCurrent(mode api.ChargeMode, sitePower, batteryPower f
 	targetCurrent := max(effectiveCurrent+deltaCurrent, 0)
 
 	// in MinPV mode or under special conditions return at least minCurrent
-	if battery := batteryStart || batteryBuffered && lp.charging() || lp.GetBatteryBoost() == boostContinue; (mode == api.ModeMinPV || battery) && targetCurrent < minCurrent {
+	if (mode == api.ModeMinPV || battery) && targetCurrent < minCurrent {
 		lp.log.DEBUG.Printf("pv charge current: min %.3gA > %.3gA (%.0fW @ %dp, battery: %t)", minCurrent, targetCurrent, sitePower, activePhases, battery)
 		return minCurrent
 	}

core/loadpoint_phases_test.go

@@ -178,7 +178,7 @@ func testScale(t *testing.T, lp *Loadpoint, sitePower float64, direction string,
 		// scale-up should only execute when the 1p max current is exceeded
 		// we're testing this here and remove the upscale expectation for the following test below 1p max current
 		if maxAmp := -sitePower / Voltage; maxAmp < maxA {
-			if scaled := lp.pvScalePhases(sitePower, minA, maxAmp-0.0001); scaled != 3 {
+			if scaled := lp.pvScalePhases(sitePower, minA, maxAmp-0.0001, true); scaled != 3 {
 				t.Errorf("%v act=%d max=%d missing scale %s at reduced max current %.1fA", tc, act, max, direction, maxAmp)
 			}
 
@@ -187,7 +187,7 @@ func testScale(t *testing.T, lp *Loadpoint, sitePower float64, direction string,
 		}
 	}
 
-	scaled := lp.pvScalePhases(sitePower, minA, maxA)
+	scaled := lp.pvScalePhases(sitePower, minA, maxA, true)
 
 	if strings.Contains(testExpectation, testDirection) {
 		if scaled == 0 {
@@ -384,6 +384,13 @@ func TestPvScalePhasesTimer(t *testing.T) {
 			lp.chargePower = 3 * Voltage * minA
 		}},
 
+		// minpv never disables, so scale down even if 1p is not sustainable (#33208)
+		{"3/3->1, insufficient for 1p, charging, minpv", 3, 3, 0.1, 1, 1, func(lp *Loadpoint) {
+			lp.phaseTimer = elapsed
+			lp.enabled = true
+			lp.mode = api.ModeMinPV
+		}},
+
 		// switch down from 3p/0p while not yet charging
 		{"3/0->1, not enough power, not charging", 3, 0, 0, 1, 1, func(lp *Loadpoint) {
 			lp.status = api.StatusB
@@ -437,7 +444,7 @@ func TestPvScalePhasesTimer(t *testing.T) {
 			charger.MockPhaseSwitcher.EXPECT().Phases1p3p(tc.toPhases).Return(nil)
 		}
 
-		res := lp.pvScalePhases(tc.sitePower, minA, maxA)
+		res := lp.pvScalePhases(tc.sitePower, minA, maxA, lp.mode != api.ModeMinPV)
 
 		require.Equal(t, tc.res, res, tc.desc)
 		require.Equal(t, tc.toPhases, lp.phases, tc.desc)
@@ -785,7 +792,7 @@ func TestPvScalePhasesCircuitLimits(t *testing.T) {
 				}{plainCharger, phaseCharger},
 			}
 
-			require.Equal(t, tc.expectedPhases, lp.pvScalePhases(tc.sitePower, lp.minCurrent, lp.maxCurrent))
+			require.Equal(t, tc.expectedPhases, lp.pvScalePhases(tc.sitePower, lp.minCurrent, lp.maxCurrent, true))
 
 			ctrl.Finish()
 		})