C*******************************************************************

      SUBROUTINE TYPE73(TIME,XIN,OUT,T,DTDT,PAR,INFO,ICNTRL,*)

C     version from: 12/22/89
C     SAMPLE INPUT AND OUTPUT VALUES FOLLOW THE VARIABLE DEFINITIONS
C*******************************************************************
C**** Subroutine represents a charge controller for a system including
C**** PV-array, load and battery storage.
C**** The controler represents a series type controler.
C**** A blocking diode is included in the model. It prevents that the 
C**** battery is being discharged through the cell. It is assumed that
C**** voltage drop at the diode is constant throughout the simulation
C**** and just depends on the diode material used in the system.
C**** The user has to provide this information as a parameter 
C*******************************************************************

C     Variables:

C     VB -- battery voltage [volts]
C     VD -- low limit on voltage, when battery discharging
C     VC -- high limit on voltage, when battery charging: cutoff voltage
C     VDA -- limit on voltage, above battery can again begin to discharge
C            after being charged
C     VCA -- limit on voltage, above battery can again begin to charge
C            after being discharged
C     VDIODE -- voltage of diode
C     VCELL -- voltage send to cell
C     VLOAD -- voltage send to load   
C     F -- fractional state of charge
C     FD -- discharge limit on F
C     FC -- charge limit on F
C     FDA -- limit on F above battery can be discharged again after
C            being charged
C     FCA -- limit on F below battery can be charged again after
C            being discharged
C     IBMIN,IBMAX -- min. and max. battery current permitted
C     IB -- battery current
C**************************************************************  	
C
C     SAMPLE INPUT AND OUTPUT VALUES
C
C     INPUT               SAMPLE VALUES
C     XIN(1) VB               220.0
C     XIN(2) IB                25.0
C     XIN(3)  F                  .9
C     XIN(4) VC               225.0
C     XIN(5) VD               200.0
C
C     PARAMETERS
C     PAR(1) FD                  .7
C     PAR(2) FC                 1.0
C     PAR(3) FDA                 .72
C     PAR(4) FCA                 .98
C     PAR(5) VDA              223.0
C     PAR(6) VCA              215.0
C     PAR(7) IBMAX             40.0
C     PAR(8) IBMIN            -40.0
C     PAR(9) VDIODE              .7
C
C     OUTPUTS
C     OUT(1) VCELL            220.7
C     OUT(2) VLOAD            220.0
C     OUT(3) FAIL               0.0
C
C*****************************************************************
 
      IMPLICIT NONE
	
	DOUBLE PRECISION XIN, OUT
      INTEGER INFO
      INTEGER ISTORE,NSTORE,IAV
      REAL TIME,T,DTDT,ICNTRL,PAR,S
      REAL VB,VC,VD,V,VDA,VCA,VDIODE,IB
      REAL F,FD,FC,FDA,FCA,IBMIN,IBMAX,FAIL
      REAL VCELL,VLOAD,DUMMY	
      DIMENSION XIN(5), OUT(3), PAR(9), INFO(15)


      COMMON /STORE/ NSTORE,IAV,S(5000)
C**** store is used to store values from previous timestep

C**********************************************************

      INFO(6)=3
      INFO(9)=0

C--------------------------------------------------------
C**** Initial call of component
      IF(INFO(7).LT.0)THEN

C****   storage allocation
        INFO(10)=1
        CALL TYPECK(1,INFO,5,9,0)
        ISTORE=INFO(10)

C****   Iinitialization of auxiliary variables used in secant
C****   method
        S(ISTORE)=0.			


C****   SET PARAMETERS
        FD=PAR(1)
	FC=PAR(2)
        FDA=PAR(3)
        FCA=PAR(4)
        VDA=PAR(5)
        VCA=PAR(6)
        IBMAX=PAR(7)
        IBMIN=PAR(8)
	VDIODE=PAR(9)

	DUMMY=0.

C------------------------------------------------------
C**** first and following calls in time step
      ELSE

	DUMMY=S(ISTORE)

C****   Following calls in time step
C****   Set inputs
        VB=XIN(1)
        IB=XIN(2)
        F=XIN(3)
        VC=XIN(4)
        VD=XIN(5)

C****   check on discharge rate
        IF(IB.LT.0.)THEN
       	  IF(IB.LT.IBMIN)THEN
      	    FAIL=1
          ENDIF
        ELSE
      	  IF(IB.GT.IBMAX)THEN
            FAIL=2
      	  ENDIF
        ENDIF		


C****   initially no restrictions are made, battery can either 
C****   be charged or discharged 
	IF(DUMMY.EQ.0.)THEN

C****     check on low limit of F and V
	  IF((F.LT.FD).OR.(VB.LT.VD))THEN
C****       load will be disconnected from battery and from cell,
C****       but cell can still charge battery
	  
	    VLOAD=0.
	    VCELL=VDIODE+VB
	    DUMMY=1.
	
C****     check on high limit of voltage
	  ELSEIF((F.GT.FC).OR.(VB.GT.VC))THEN
C****       cell will be disconnected from battery and load,
C****       battery will be discharged

	    VCELL=-333.
C****       this is just a characteristic value that the cell 
C****       recognizes that it is being disconnected  
	    VLOAD=VB
	    DUMMY=2.

	  ELSE
C****       no restrictions
	      	    
	    VCELL=VDIODE+VB
	    VLOAD=VB
	  ENDIF

	ELSEIF(DUMMY.EQ.1.)THEN
C****     battery can only begin to discharge again, when VB is
C****     greater than VDA and F is greater then FDA
	  
	  IF((F.LT.FDA).OR.(VB.LT.VDA))THEN
	    VLOAD=0.
	    VCELL=VDIODE+VB
	  ELSE
C****       no restrictions
	      	    
	    VCELL=VDIODE+VB
	    VLOAD=VB
	    DUMMY=0.
	  ENDIF

	ELSEIF(DUMMY.EQ.2.)THEN
C****     battery can only begin to charge again, when VB is
C****     less than VCA and F is less than FCA
	    
	  IF((F.GT.FCA).OR.(VB.GT.VCA))THEN
	    VCELL=-333.
	    VLOAD=VB
	    DUMMY=2.
	  ELSE
C****       no restrictions
	      	    
	    VCELL=VDIODE+VB
	    VLOAD=VB
	    DUMMY=0.
	  ENDIF
        ENDIF
      ENDIF

      S(ISTORE)=DUMMY	

C**** SET OUTPUTS
      OUT(1)=VCELL
      OUT(2)=VLOAD
      OUT(3)=FAIL

	RETURN 1
      END