Methods and apparatus are provided for controlling a stand-alone four-leg
three-phase inverter. The inverter three-phase output is converted from AC domain
elements to corresponding DC domain elements. The DC domain elements are processed
into combined regulating and imbalance compensating signals, including over-current
limiting. The compensating signals are restored to corresponding AC domain signals,
and are processed into control inputs for the inverter, in order to stabilize the
inverter output when connected to an unbalanced load. The inverter controller can
be implemented entirely in software as a control algorithm.
