Abstract: There is provided an electric traction system 1, comprising: a traction converter module 2 comprising: a positive input terminal 4 and a negative input terminal 6 for operatively coupling to a DC power supply, and a plurality of power inverters 11, each of which comprises positive and negative input nodes 3, 5 configured to receive DC power and output nodes 9 configured to supply AC power, wherein the positive and negative input nodes 3, 5 of the plurality of power inverters 11 are electrically connected in series between the positive input terminal 4 and the negative input terminal 6; and at least one electric motor 8 configured to be driven by the traction converter module 2, the at least one electric motor 8 comprising a multi-phase electric motor 81.

Abstract: There is provided an electric traction system, comprising: a step-down transformer comprising a primary winding for operatively coupling to an AC power supply and a secondary winding which is inductively coupled to the primary winding; a traction converter module comprising a first input terminal and a second input terminal which are operatively coupled to the secondary winding, and a plurality of AC-to-AC power converters, each of which comprises first and second input nodes, configured to receive AC power and output nodes configured to supply AC power, wherein the first and second input nodes, of the plurality of AC-to-AC power converters are electrically connected in series between the first input terminal and the second input terminal; and at least one electric motor configured to be driven by the traction converter module.

Abstract: Provided are a method and system for controlling a voltage. The method includes: acquiring a current output voltage of an inverter; calculating a current voltage error of the current output voltage relative to a given output voltage; inputting the current voltage error into a fuzzy controller to determine a target output voltage of the inverter; determining an amplitude adjustment command based on a difference between an amplitude of the target output voltage and an amplitude of the current output voltage; determining a phase adjustment command based on a difference between a phase of the target output voltage and a phase of the current output voltage; and adjusting an amplitude and a phase of an output voltage of the inverter according to the amplitude adjustment command and the phase adjustment command respectively, to maintain the output voltage of the inverter within a preset range.

Abstract: Provided are a method and system for controlling a voltage. The method includes: acquiring a current output voltage of an inverter; calculating a current voltage error of the current output voltage relative to a given output voltage; inputting the current voltage error into a fuzzy controller to determine a target output voltage of the inverter; determining an amplitude adjustment command based on a difference between an amplitude of the target output voltage and an amplitude of the current output voltage; determining a phase adjustment command based on a difference between a phase of the target output voltage and a phase of the current output voltage; and adjusting an amplitude and a phase of an output voltage of the inverter according to the amplitude adjustment command and the phase adjustment command respectively, to maintain the output voltage of the inverter within a preset range.