// Three phase sine voltage source with voltage and frequency control inputs.
// The four outputs are labeled pha, phb, phc and phn (can be connected
// to gnd or considered as a floating point). Phase pha is the
// reference phase. Phases phb & phc lead and lag by 120 deg, respectively.


module  vsrc_3ph(amp,fre,gnd,pha,phb,phc,phn);
 input amp,fre,gnd;
 output pha,phb,phc,phn;

 voltage amp,fre,gnd;
 voltage pha,phb,phc,phn;

 parameter real ka=1.0, // coefficient on the magnitude
                kf=1.0, // coefficient on the frequency
                phi=0;  // phase difference

 real phia,phib,phic,vamp,wfre;

 analog begin
  if (analysis("static")) begin
    @(initial_step) begin
       phia = phi;                      // phase difference on phase a
       phib = phi + `M_TWO_PI/3.0;      // phase difference on phase b
       phic = phi - `M_TWO_PI/3.0;      // phase difference on phase c
    end
  end
  wfre = kf*`M_TWO_PI*V(fre,gnd);
  vamp = ka*V(amp,gnd);
  V(pha,phn) <+ vamp*sin(wfre*$realtime + phia);
  V(phb,phn) <+ vamp*sin(wfre*$realtime + phib);
  V(phc,phn) <+ vamp*sin(wfre*$realtime + phic);
  bound_step(0.05/wfre);

  V(pha,phn) <+ ac_stim("ac",vamp,phia);
  V(phb,phn) <+ ac_stim("ac",vamp,phib);
  V(phc,phn) <+ ac_stim("ac",vamp,phic);
 end
endmodule