Fix low wind speed pitch+torque saturation bug

Ben-Mertz · Jul 22, 2020 · 5f92876 · 5f92876
1 parent b3df093
commit 5f92876
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Showing 4 changed files with 13 additions and 14 deletions.
diff --git a/src/ControllerBlocks.f90 b/src/ControllerBlocks.f90
@@ -55,7 +55,7 @@ SUBROUTINE StateMachine(CntrPar, LocalVar)
         ! Initialize State machine if first call
         IF (LocalVar%iStatus == 0) THEN ! .TRUE. if we're on the first call to the DLL
 
-            IF (LocalVar%PitCom(1) >= CntrPar%VS_Rgn3Pitch) THEN ! We are in region 3
+            IF (LocalVar%PitCom(1) >= LocalVar%VS_Rgn3Pitch) THEN ! We are in region 3
                 IF (CntrPar%VS_ControlMode == 1) THEN ! Constant power tracking
                     LocalVar%VS_State = 5
                     LocalVar%PC_State = 1
@@ -78,14 +78,12 @@ SUBROUTINE StateMachine(CntrPar, LocalVar)
             END IF
 
             ! --- Torque control state machine ---
-            IF (LocalVar%PC_PitComT >= CntrPar%VS_Rgn3Pitch) THEN       
+            IF (LocalVar%PC_PitComT >= LocalVar%VS_Rgn3Pitch) THEN       
 
-                IF (LocalVar%PC_PitComT >= LocalVar%PC_MinPit + CntrPar%PC_Switch) THEN ! Make sure we aren't implement pitch saturation
-                    IF (CntrPar%VS_ControlMode == 1) THEN                   ! Region 3
-                        LocalVar%VS_State = 5 ! Constant power tracking
-                    ELSE 
-                        LocalVar%VS_State = 4 ! Constant torque tracking
-                    END IF
+                IF (CntrPar%VS_ControlMode == 1) THEN                   ! Region 3
+                    LocalVar%VS_State = 5 ! Constant power tracking
+                ELSE 
+                    LocalVar%VS_State = 4 ! Constant torque tracking
                 END IF
             ELSE
                 IF (LocalVar%GenArTq >= CntrPar%VS_MaxOMTq*1.01) THEN       ! Region 2 1/2 - active PI torque control

diff --git a/src/Controllers.f90 b/src/Controllers.f90
@@ -88,9 +88,9 @@ SUBROUTINE PitchControl(avrSWAP, CntrPar, LocalVar, objInst)
         ! Pitch Saturation
         IF (CntrPar%PS_Mode == 1) THEN
             LocalVar%PC_MinPit = PitchSaturation(LocalVar,CntrPar,objInst)
-            LocalVar%PC_MinPit = max(LocalVar%PC_MinPit, CntrPar%PC_MinPit)
+            LocalVar%PC_MinPit = max(LocalVar%PC_MinPit, CntrPar%PC_FinePit)
         ELSE
-            LocalVar%PC_MinPit = CntrPar%PC_MinPit
+            LocalVar%PC_MinPit = CntrPar%PC_FinePit
         ENDIF
 
         ! Shutdown

diff --git a/src/ROSCO_Types.f90 b/src/ROSCO_Types.f90
@@ -129,7 +129,6 @@ MODULE ROSCO_Types
     REAL(4)                             :: PC_RtTq99                    ! 99% of the rated torque value, using for switching between pitch and torque control, [Nm].
     REAL(4)                             :: VS_MaxOMTq                   ! Maximum torque at the end of the below-rated region 2, [Nm]
     REAL(4)                             :: VS_MinOMTq                   ! Minimum torque at the beginning of the below-rated region 2, [Nm]
-    REAL(4)                             :: VS_Rgn3Pitch                 ! Pitch angle at which the state machine switches to region 3, [rad].
 
 END TYPE ControlParameters
 
@@ -184,6 +183,7 @@ MODULE ROSCO_Types
     REAL(4)                             :: VS_SpdErrBr                  ! Current speed error for region 1.5 PI controller (generator torque control) [rad/s].
     REAL(4)                             :: VS_SpdErr                    ! Current speed error for tip-speed-ratio tracking controller (generator torque control) [rad/s].
     INTEGER(4)                          :: VS_State                     ! State of the torque control system
+    REAL(4)                             :: VS_Rgn3Pitch                 ! Pitch angle at which the state machine switches to region 3, [rad].
     REAL(4)                             :: WE_Vw                        ! Estimated wind speed [m/s]
     REAL(4)                             :: WE_Vw_F                      ! Filtered estimated wind speed [m/s]
     REAL(4)                             :: WE_VwI                       ! Integrated wind speed quantity for estimation [m/s]

diff --git a/src/ReadSetParameters.f90 b/src/ReadSetParameters.f90
@@ -215,7 +215,6 @@ SUBROUTINE ReadControlParameterFileSub(CntrPar, accINFILE, accINFILE_size)!, acc
         CntrPar%PC_RtTq99 = CntrPar%VS_RtTq*0.99
         CntrPar%VS_MinOMTq = CntrPar%VS_Rgn2K*CntrPar%VS_MinOMSpd**2
         CntrPar%VS_MaxOMTq = CntrPar%VS_Rgn2K*CntrPar%VS_RefSpd**2
-        CntrPar%VS_Rgn3Pitch = CntrPar%PC_FinePit + CntrPar%PC_Switch
 
         CLOSE(UnControllerParameters)
 
@@ -283,8 +282,10 @@ SUBROUTINE ComputeVariablesSetpoints(CntrPar, LocalVar, objInst)
         ! Define transition region setpoint errors
         LocalVar%VS_SpdErrAr = VS_RefSpd - LocalVar%GenSpeedF               ! Current speed error - Region 2.5 PI-control (Above Rated)
         LocalVar%VS_SpdErrBr = CntrPar%VS_MinOMSpd - LocalVar%GenSpeedF     ! Current speed error - Region 1.5 PI-control (Below Rated)
-
-
+
+        ! Region 3 minimum pitch angle for state machine
+        LocalVar%VS_Rgn3Pitch = LocalVar%PC_MinPit + CntrPar%PC_Switch
+
     END SUBROUTINE ComputeVariablesSetpoints
     ! -----------------------------------------------------------------------------------
     ! Read avrSWAP array passed from ServoDyn