Problem with DC voltage output from Boost type converter when adding another to its output.

I have two boost type converters. When run individually SIDE 1 outputs 148vdc with a 30vdc input. SIDE 2 with an input of 148vdc has an output of 602vdc (shown in First Figuire). I would expect if i join these two converters together that SIDE 1 would supply SIDE 2 with 148vdc and the output from SIDE 2 would be 602vdc (shown in Second Figuire), this is not the case.

As shown when the circuits are combined (Second Figuire) the output from SIDE 1 is only 76vdc and the output from SIDE 2 is 309vdc. Why isn't the SIDE 1 output 148vdc? How can I get the output from SIDE 1 correct?

Answer 1

[Joel Van Sickel]

It looks like you are using open loop control and the first converter is supplying it's original load PLUS the new load of the second converter. In this case, it isn't that surprising that it could be outputting a lower voltage, which would effect the rest of the system.