Defining of current deviation

Hi,

I need to define current deviation of sinusoidal rectifier (sinusoidal
input current) using PI regulator/in PSPICE/.


PI REGULATOR /expample/


.PARAM Kp=0.3 ;
.PARAM Ti=0.5 ;

.TRAN 1m 1 0 1m UIC
.PROBE

.MODEL zener D BV=100

Ieps 0 1 pwl( 0 0
+ 0.1 0
+ 0.101 (VOLTAGE DEVIATION) )

* SYMMETRICAL REGULATOR
* ------------------------
*Rp 1 2 {Kp}
*Ci 2 0 {Ti}
*Dza 0 1 zener

* ASYMMETRICAL REGULATOR
* ---------------------
Rp 1 2 {Kp}
Ci 2 0 {Ti}
Dza 0 3 zener
Dza1 1 3 zener

.END


Supply Voltages

Ep1 101 0 VALUE {
+ Ugmax*sgn(Iz*sin(omz*TIME-pi-alfap)+I(Vz1)+dh*V(101)/Ugmax)}
Ep2 102 0 VALUE {
+ Ugmax*sgn(Iz*sin(omz*TIME-fiz-pi-alfap)+I(Vz2)+dh*V(102)/Ugmax)}
Ep3 103 0 VALUE {
+ Ugmax*sgn(Iz*sin(omz*TIME+fiz-pi-alfap)+I(Vz3)+dh*V(103)/Ugmax)}


I must put my formula in place of Iz to hold average output volatege/in spite of changing load/. And I dont know how to solve this problem :/
thanks in advance