When paralleling droop controlled dc-dc converters, should the internal voltage and current loop controllers be designed to account for other paralleled converters in the network? Currently I've modelled a two dc-dc boost converter and single resistive load network with line resistances. The two converter controllers are type 3 compensators (in voltage control mode) which were designed irrespective of its neighbouring converter. Converter output voltage restoration and equal current sharing is enabled via decentralised secondary controllers, however if I want to increase the current sharing ratio of one converter (i.e. one converter takes care of more of the load) system performance becomes unsatisfactory. I'm wondering maybe this is to do with having designed the internal controllers separately as a SISO system - do people design these controllers as MIMO? Maybe since I'm not actively controlling the inductor current internally (current mode control), then the secondary average current controller isn't that effective. Any thoughts would be great, cheers folks.
Hi Daniel,
A good reference for you to work with is Phil Krein's well known book:
P. T. Krein, Elements of Power Electronics. Oxford University Press, 1998 or subsequent editions.
Cheers !
-Sanjay
Hi,
Generally speaking, if you want to put multiple power supplies working in parallel, all these power supplies may need to be current sourced. It means you can implement output current control (instead of voltage control) for each converter.
Maybe you also have to maintain the output voltage in your network, in this case, you can design 1 converter with output voltage control, and use output current control for the rests. By controlling the current of the control controlled converter, you can control the output current of the voltage controlled converter indirectly
Note that, what mentioned above is only an idea, Sounds possible to me but I never try.
Thanks for that. When referring to output current control, are you talking about droop control (which I have already employed) or internal inductor current control of each converter?
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