An electrical system including: a first three-phase AC supply and a second three-phase AC supply; a phase-shifting transformer, connected to and configured to receive AC power from each of the first three-phase AC supply and the second three-phase AC supply, said phase-shifting transformer applying a 30° phase shift to each of the received AC powers to thereby generate a first transformed AC current and a second transformed AC current; a first rectifier circuit and a second rectifier circuit, each connected to the phase-shifting transformer and configured to receive the first transformed AC current and the second transformed AC current respectively, said rectifier circuits generating a first DC voltage and a second DC voltage; a first inverter circuit and a second inverter circuit, respectively connected to the first rectifier circuit and the second rectifier circuit, said inverter circuits generating a first AC output voltage and a second AC output voltage from the first DC voltage and second DC voltage respectively; and a load, connected to and configured to receive the first AC output voltage and the second AC output voltage, wherein the load is an open stator winding motor drive; a control subsystem, said control subsystem operating to reduce or cancel circulation current within the electrical system, wherein the control subsystem is a resonant controller and wherein the resonant frequency 3ωi of the resonant controller is set to three times the grid frequency ωi, characterised in that: the phase-shifting transformer is a polygonal phase-shifter autotransformer; and the control subsystem is configured to produce non-sinusoidal modulation references ( v a, v b, v c) for controlling the first inverter circuit and the second inverter circuit, thereby producing three-phase balanced sinusoidal machine stator currents ( i a, i b, i c), and wherein the modulation references for the first inverter circuit and the second inverter circuit are set opposite to each other in order to maximise the machine stator winding voltage for each phase, thus better utilizing the DC bus voltage. a first three-phase AC supply and a second three-phase AC supply; a phase-shifting transformer, connected to and configured to receive AC power from each of the first three-phase AC supply and the second three-phase AC supply, said phase-shifting transformer applying a 30° phase shift to each of the received AC powers to thereby generate a first transformed AC current and a second transformed AC current; a first rectifier circuit and a second rectifier circuit, each connected to the phase-shifting transformer and configured to receive the first transformed AC current and the second transformed AC current respectively, said rectifier circuits generating a first DC voltage and a second DC voltage; a first inverter circuit and a second inverter circuit, respectively connected to the first rectifier circuit and the second rectifier circuit, said inverter circuits generating a first AC output voltage and a second AC output voltage from the first DC voltage and second DC voltage respectively; and a load, connected to and configured to receive the first AC output voltage and the second AC output voltage, wherein the load is an open stator winding motor drive; a control subsystem, said control subsystem operating to reduce or cancel circulation current within the electrical system, wherein the control subsystem is a resonant controller and wherein the resonant frequency 3ωi of the resonant controller is set to three times the grid frequency ωi, characterised in that: the phase-shifting transformer is a polygonal phase-shifter autotransformer; and the control subsystem is configured to produce non-sinusoidal modulation references ( v a, v b, v c) for controlling the first inverter circuit and the second inverter circuit, thereby producing three-phase balanced sinusoidal machine stator currents ( i a, i b, i c), and wherein the modulation references for the first inverter circuit and the second inverter circuit are set opposite to each other in order to maximise the machine stator winding voltage for each phase, thus better utilizing the DC bus voltage. the phase-shifting transformer is a polygonal phase-shifter autotransformer; and the control subsystem is configured to produce non-sinusoidal modulation references ( v a, v b, v c) for controlling the first inverter circuit and the second inverter circuit, thereby producing three-phase balanced sinusoidal machine stator currents ( i a, i b, i c), and wherein the modulation references for the first inverter circuit and the second inverter circuit are set opposite to each other in order to maximise the machine stator winding voltage for each phase, thus better utilizing the DC bus voltage.