AC voltage with constant amplitude and phase when 'vType' is 'parameter',
with variable amplitude and phase when 'vType' is 'signal'.
Optional input:
omega_in angular frequency (choose fType == "Signal")
vPhasor_in {eff(v), phase(v)}
vPhasor_in[1] in SI or pu, depending on choice of 'units'
vPhasor_in[2] in rad