IPC Saturation Fix [RAAW]

ROSCO/rosco_registry/rosco_types.yaml

@@ -136,6 +136,9 @@ ControlParameters:
     IPC_IntSat:
       <<: *real
       description: Integrator saturation (maximum signal amplitude contrbution to pitch from IPC)
+    IPC_SatMode:
+      <<: *integer
+      description: IPC Saturation method IPC Saturation method (0 - no saturation (except by PC_MinPit), 1 - saturate by PS_BldPitchMin, 2 - saturate sotfly (full IPC cycle) by PC_MinPit, 3 - saturate softly by PS_BldPitchMin)
     IPC_KP:
       <<: *real
       description: Integral gain for the individual pitch controller, [-].
@@ -723,6 +726,9 @@ LocalVariables:
       <<: *real
       description: Blade pitch [rad]
       size: 3
+    BlPitchCMeas: 
+      <<: *real
+      description: Mean (collective) blade pitch [rad]
     Azimuth: 
       <<: *real 
       description: Rotor aziumuth angle [rad]
@@ -824,6 +830,9 @@ LocalVariables:
       <<: *real
       description: Proportional gain for IPC, after ramp [-]
       size: 2
+    IPC_IntSat:
+      <<: *real
+      description: Integrator saturation (maximum signal amplitude contrbution to pitch from IPC)
     PC_State:                     
       <<: *integer 
       description: State of the pitch control system

ROSCO/src/ControllerBlocks.f90

@@ -206,10 +206,10 @@ SUBROUTINE WindSpeedEstimator(LocalVar, CntrPar, objInst, PerfData, DebugVar, Er
             WE_Inp_Speed = LocalVar%RotSpeedF
         END IF
 
-        IF (LocalVar%BlPitch(1) < CntrPar%PC_MinPit) THEN
+        IF (LocalVar%BlPitchCMeas < CntrPar%PC_MinPit) THEN
             WE_Inp_Pitch = CntrPar%PC_MinPit
         ELSE
-            WE_Inp_Pitch = LocalVar%BlPitch(1)
+            WE_Inp_Pitch = LocalVar%BlPitchCMeas
         END IF
 
         IF (LocalVar%VS_LastGenTrqF < 0.0001 * CntrPar%VS_RtTq) THEN
@@ -228,7 +228,7 @@ SUBROUTINE WindSpeedEstimator(LocalVar, CntrPar, objInst, PerfData, DebugVar, Er
         ! Inversion and Invariance Filter implementation
         IF (CntrPar%WE_Mode == 1) THEN      
             ! Compute AeroDynTorque
-            Tau_r = AeroDynTorque(LocalVar%RotSpeedF, LocalVar%BlPitch(1), LocalVar, CntrPar, PerfData, ErrVar)
+            Tau_r = AeroDynTorque(LocalVar%RotSpeedF, LocalVar%BlPitchCMeas, LocalVar, CntrPar, PerfData, ErrVar)
 
             LocalVar%WE_VwIdot = CntrPar%WE_Gamma/CntrPar%WE_Jtot*(LocalVar%VS_LastGenTrq*CntrPar%WE_GearboxRatio - Tau_r)
             LocalVar%WE_VwI = LocalVar%WE_VwI + LocalVar%WE_VwIdot*LocalVar%DT
@@ -413,7 +413,7 @@ REAL(DbKi) FUNCTION Shutdown(LocalVar, CntrPar, objInst)
 
         ! Pitch Blades to 90 degrees at max pitch rate if in shutdown mode
         IF (LocalVar%SD) THEN
-            Shutdown = LocalVar%BlPitch(1) + CntrPar%PC_MaxRat*LocalVar%DT
+            Shutdown = LocalVar%BlPitchCMeas + CntrPar%PC_MaxRat*LocalVar%DT
             IF (MODULO(LocalVar%Time, 10.0_DbKi) == 0) THEN
                 print *, ' ** SHUTDOWN MODE **'
             ENDIF

ROSCO/src/Controllers.f90

@@ -96,17 +96,23 @@ SUBROUTINE PitchControl(avrSWAP, CntrPar, LocalVar, objInst, DebugVar, ErrVar)
 
         ! Saturate collective pitch commands:
         LocalVar%PC_PitComT = saturate(LocalVar%PC_PitComT, LocalVar%PC_MinPit, CntrPar%PC_MaxPit)                    ! Saturate the overall command using the pitch angle limits
-        LocalVar%PC_PitComT = ratelimit(LocalVar%PC_PitComT, CntrPar%PC_MinRat, CntrPar%PC_MaxRat, LocalVar%DT, LocalVar%restart, LocalVar%rlP,objInst%instRL) ! Saturate the overall command of blade K using the pitch rate limit
+        LocalVar%PC_PitComT = ratelimit(LocalVar%PC_PitComT, CntrPar%PC_MinRat, CntrPar%PC_MaxRat, LocalVar%DT, LocalVar%restart, LocalVar%rlP,objInst%instRL,LocalVar%BlPitchCMeas) ! Saturate the overall command of blade K using the pitch rate limit
         LocalVar%PC_PitComT_Last = LocalVar%PC_PitComT
 
         ! Combine and saturate all individual pitch commands in software
         DO K = 1,LocalVar%NumBl ! Loop through all blades, add IPC contribution and limit pitch rate
             LocalVar%PitCom(K) = LocalVar%PC_PitComT + LocalVar%FA_PitCom(K) 
             LocalVar%PitCom(K) = saturate(LocalVar%PitCom(K), LocalVar%PC_MinPit, CntrPar%PC_MaxPit)                    ! Saturate the command using the pitch satauration limits
             LocalVar%PitCom(K) = LocalVar%PitCom(K) + LocalVar%IPC_PitComF(K)                                          ! Add IPC
-            LocalVar%PitCom(K) = saturate(LocalVar%PitCom(K), LocalVar%PC_MinPit, CntrPar%PC_MaxPit)                    ! Saturate the command using the absolute pitch angle limits
-            LocalVar%PitCom(K) = ratelimit(LocalVar%PitCom(K), CntrPar%PC_MinRat, CntrPar%PC_MaxRat, LocalVar%DT, LocalVar%restart, LocalVar%rlP,objInst%instRL) ! Saturate the overall command of blade K using the pitch rate limit
-        END DO
+
+            ! Hard IPC saturation by peak shaving limit
+            IF (CntrPar%IPC_SatMode == 1) THEN
+                LocalVar%PitCom(K) = saturate(LocalVar%PitCom(K), LocalVar%PC_MinPit, CntrPar%PC_MaxPit)  
+            END IF
+
+            ! Rate limit                  
+            LocalVar%PitCom(K) = ratelimit(LocalVar%PitCom(K), CntrPar%PC_MinRat, CntrPar%PC_MaxRat, LocalVar%DT, LocalVar%restart, LocalVar%rlP,objInst%instRL,LocalVar%BlPitch(K)) ! Saturate the overall command of blade K using the pitch rate limit
+        END DO 
 
         ! Open Loop control, use if
         !   Open loop mode active         Using OL blade pitch control      
@@ -134,9 +140,9 @@ SUBROUTINE PitchControl(avrSWAP, CntrPar, LocalVar, objInst, DebugVar, ErrVar)
         ! Hardware saturation: using CntrPar%PC_MinPit
         DO K = 1,LocalVar%NumBl ! Loop through all blades, add IPC contribution and limit pitch rate
             ! Saturate the pitch command using the overall (hardware) limit
-            LocalVar%PitComAct(K) = saturate(LocalVar%PitComAct(K), LocalVar%PC_MinPit, CntrPar%PC_MaxPit)
+            LocalVar%PitComAct(K) = saturate(LocalVar%PitComAct(K), CntrPar%PC_MinPit, CntrPar%PC_MaxPit)
             ! Saturate the overall command of blade K using the pitch rate limit
-            LocalVar%PitComAct(K) = ratelimit(LocalVar%PitComAct(K), CntrPar%PC_MinRat, CntrPar%PC_MaxRat, LocalVar%DT, LocalVar%restart, LocalVar%rlP,objInst%instRL) ! Saturate the overall command of blade K using the pitch rate limit
+            LocalVar%PitComAct(K) = ratelimit(LocalVar%PitComAct(K), CntrPar%PC_MinRat, CntrPar%PC_MaxRat, LocalVar%DT, LocalVar%restart, LocalVar%rlP,objInst%instRL,LocalVar%BlPitch(K)) ! Saturate the overall command of blade K using the pitch rate limit
         END DO
 
         ! Add pitch actuator fault for blade K
@@ -413,15 +419,26 @@ SUBROUTINE IPC(CntrPar, LocalVar, objInst, DebugVar, ErrVar)
             LocalVar%IPC_KP(i) = sigma(LocalVar%WE_Vw, CntrPar%IPC_Vramp(1), CntrPar%IPC_Vramp(2), 0.0_DbKi, CntrPar%IPC_KP(i), ErrVar)
             LocalVar%IPC_KI(i) = sigma(LocalVar%WE_Vw, CntrPar%IPC_Vramp(1), CntrPar%IPC_Vramp(2), 0.0_DbKi, CntrPar%IPC_KI(i), ErrVar)
         END DO
+
+        ! Handle saturation limit, depends on IPC_SatMode
+        IF (CntrPar%IPC_SatMode == 2) THEN
+            ! Saturate to min allowed pitch angle, softly using IPC_IntSat
+            LocalVar%IPC_IntSat = min(CntrPar%IPC_IntSat,LocalVar%BlPitchCMeas - CntrPar%PC_MinPit)
+        ELSEIF (CntrPar%IPC_SatMode == 3) THEN
+            ! Saturate to peak shaving, softly using IPC_IntSat
+            LocalVar%IPC_IntSat = min(CntrPar%IPC_IntSat,LocalVar%BlPitchCMeas - LocalVar%PC_MinPit)
+        ELSE
+            LocalVar%IPC_IntSat = CntrPar%IPC_IntSat
+        ENDIF
 
         ! Integrate the signal and multiply with the IPC gain
         IF ((CntrPar%IPC_ControlMode >= 1) .AND. (CntrPar%Y_ControlMode /= 2)) THEN
-            LocalVar%IPC_axisTilt_1P = PIController(axisTilt_1P, LocalVar%IPC_KP(1), LocalVar%IPC_KI(1), -CntrPar%IPC_IntSat, CntrPar%IPC_IntSat, LocalVar%DT, 0.0_DbKi, LocalVar%piP, LocalVar%restart, objInst%instPI) 
-            LocalVar%IPC_axisYaw_1P = PIController(axisYawF_1P, LocalVar%IPC_KP(1), LocalVar%IPC_KI(1), -CntrPar%IPC_IntSat, CntrPar%IPC_IntSat, LocalVar%DT, 0.0_DbKi, LocalVar%piP, LocalVar%restart, objInst%instPI) 
+            LocalVar%IPC_axisTilt_1P = PIController(axisTilt_1P, LocalVar%IPC_KP(1), LocalVar%IPC_KI(1), -LocalVar%IPC_IntSat, LocalVar%IPC_IntSat, LocalVar%DT, 0.0_DbKi, LocalVar%piP, LocalVar%restart, objInst%instPI) 
+            LocalVar%IPC_axisYaw_1P = PIController(axisYawF_1P, LocalVar%IPC_KP(1), LocalVar%IPC_KI(1), -LocalVar%IPC_IntSat, LocalVar%IPC_IntSat, LocalVar%DT, 0.0_DbKi, LocalVar%piP, LocalVar%restart, objInst%instPI) 
 
             IF (CntrPar%IPC_ControlMode >= 2) THEN
-                LocalVar%IPC_axisTilt_2P = PIController(axisTilt_2P, LocalVar%IPC_KP(2), LocalVar%IPC_KI(2), -CntrPar%IPC_IntSat, CntrPar%IPC_IntSat, LocalVar%DT, 0.0_DbKi, LocalVar%piP, LocalVar%restart, objInst%instPI) 
-                LocalVar%IPC_axisYaw_2P = PIController(axisYawF_2P, LocalVar%IPC_KP(2), LocalVar%IPC_KI(2), -CntrPar%IPC_IntSat, CntrPar%IPC_IntSat, LocalVar%DT, 0.0_DbKi, LocalVar%piP, LocalVar%restart, objInst%instPI) 
+                LocalVar%IPC_axisTilt_2P = PIController(axisTilt_2P, LocalVar%IPC_KP(2), LocalVar%IPC_KI(2), -LocalVar%IPC_IntSat, LocalVar%IPC_IntSat, LocalVar%DT, 0.0_DbKi, LocalVar%piP, LocalVar%restart, objInst%instPI) 
+                LocalVar%IPC_axisYaw_2P = PIController(axisYawF_2P, LocalVar%IPC_KP(2), LocalVar%IPC_KI(2), -LocalVar%IPC_IntSat, LocalVar%IPC_IntSat, LocalVar%DT, 0.0_DbKi, LocalVar%piP, LocalVar%restart, objInst%instPI) 
             END IF
         ELSE
             LocalVar%IPC_axisTilt_1P = 0.0

ROSCO/src/Functions.f90

@@ -48,7 +48,7 @@ REAL(DbKi) FUNCTION saturate(inputValue, minValue, maxValue)
     END FUNCTION saturate
 
 !-------------------------------------------------------------------------------------------------------------------------------
-    REAL(DbKi) FUNCTION ratelimit(inputSignal, minRate, maxRate, DT, reset, rlP, inst)
+    REAL(DbKi) FUNCTION ratelimit(inputSignal, minRate, maxRate, DT, reset, rlP, inst, ResetValue)
     ! Saturates inputValue. Makes sure it is not smaller than minValue and not larger than maxValue
         USE ROSCO_Types, ONLY : rlParams
 
@@ -62,13 +62,18 @@ REAL(DbKi) FUNCTION ratelimit(inputSignal, minRate, maxRate, DT, reset, rlP, ins
         LOGICAL,    INTENT(IN)         :: reset  
         TYPE(rlParams), INTENT(INOUT)   :: rlP
         INTEGER(IntKi), INTENT(INOUT)   :: inst
+        REAL(DbKi), OPTIONAL,  INTENT(IN)          :: ResetValue           ! Value to base rate limit off if restarting
 
         ! Local variables
         REAL(DbKi)                 :: rate
+        REAL(DbKi)                 :: ResetValue_
+
+        ResetValue_ = inputSignal
+        IF (PRESENT(ResetValue)) ResetValue_ = ResetValue   
 
         IF (reset) THEN
-            rlP%LastSignal(inst) = inputSignal
-            ratelimit = inputSignal
+            rlP%LastSignal(inst) = ResetValue_
+            ratelimit = ResetValue_
 
         ELSE
             rate = (inputSignal - rlP%LastSignal(inst))/DT                       ! Signal rate (unsaturated)
@@ -594,6 +599,7 @@ REAL(DbKi) FUNCTION sigma(x, x0, x1, y0, y1, ErrVar)
     END FUNCTION sigma
 
 
+
 !-------------------------------------------------------------------------------------------------------------------------------
     ! Copied from NWTC_IO.f90
 !> This function returns a character string encoded with today's date in the form dd-mmm-ccyy.