Voltage control modes for microgrid applications
Methods and systems for controlling voltage output in power converters between two or more portals, where any or all portals can be DC, single phase AC, or multi-phase AC. The present methods involve determining a reference output voltage V I , measuring the output voltage V E over a power cycle, comparing V I to V E to calculate a delta voltage ΔV. ΔV can then be multiplied by a scaling parameter k to determine a current command I E . I E can then be used by a current control module in a power converter to control output current. The present methods can be implemented as an algorithm embedded in an FPGA controller connected to the power converter.
1. A microgrid system, comprising: a power source; a power-packet-switching power converter, which connects a local power source to a local microgrid having at least one physically separated load thereon; wherein the power converter includes control circuitry which monitors the converter's output voltage, modifies a commanded current value in accordance with variations in the output voltage, and drives bidirectional switches, which intermittently switch energy packets into and out of a link inductor in the converter, in dependence on the commanded current value; wherein said link inductor is directly shunted by a capacitor.
2. A power converter, comprising:
a link inductor which is directly shunted by a capacitor;
at least one input port and at least one output port;
parallel pairs of bidirectional switches each connecting each end of said link inductor to a line of one said port;
control circuitry which
monitors the converter's output voltage,
modifies a commanded current value in accordance with variations in the output voltage, and
drives said bidirectional switches, which intermittently switch energy packets into and out of the link inductor in the converter, in dependence on the commanded current value.