Yup there are several types of power control systems, there are the PMS3 units;

then there are the ZIG's they range from Marque 1 thru to the ZIG9 all different!
And some of the Converters don't always use a standard system either....
But none do any sort of heating, oil filled mains powered heaters are popular, or LPG/Diesel heaters fitted to the van.