Field winding synchronous machine drive system

A field winding synchronous machine drive system comprising:

• a field winding synchronous machine including a stator and a rotor, the stator including a stator core and N m-phase stator coils wound on the stator core to create a rotating magnetic field, where N is an integer greater than or equal to 2 and m is an integer greater than or equal to 3, the rotor including a rotor core and at least one main field winding wound on the rotor core to create field magnetic flux;
• and
• a drive apparatus configured to drive the field winding synchronous machine, the drive apparatus including N inverters each of which supplies m-phase alternating current to a corresponding one of the N m-phase stator coils,
• wherein
• each of the inverters supplies the corresponding m-phase stator coil with the m-phase alternating current which includes a fundamental-wave current and a time-harmonic current superimposed on the fundamental-wave current, the time-harmonic current having a shorter period than the fundamental-wave current,
• the m-phase alternating currents supplied respectively from the inverters to the corresponding m-phase stator coils are separately controlled, and the time-harmonic currents included in the respective m-phase alternating currents are controlled in such phases as to be weakened by one another,
• N is equal to 2,
• both of the time-harmonic currents included respectively in the two m-phase alternating currents are in the form of a triangular wave, and
• a phase shift of one of the two time-harmonic currents from the other of the two time-harmonic currents is in a range of greater than 90° and less than 270°.

A field winding synchronous machine drive system comprising:

• a field winding synchronous machine including a stator and a rotor, the stator including a stator core and N m-phase stator coils wound on the stator core to create a rotating magnetic field, where N is an integer greater than or equal to 2 and m is an integer greater than or equal to 3, the rotor including a rotor core and at least one main field winding wound on the rotor core to create field magnetic flux;
• and
• a drive apparatus configured to drive the field winding synchronous machine, the drive apparatus including N inverters each of which supplies m-phase alternating current to a corresponding one of the N m-phase stator coils,
• wherein
• each of the inverters supplies the corresponding m-phase stator coil with the m-phase alternating current which includes a fundamental-wave current and a time-harmonic current superimposed on the fundamental-wave current, the time-harmonic current having a shorter period than the fundamental-wave current,
• the m-phase alternating currents supplied respectively from the inverters to the corresponding m-phase stator coils are separately controlled, and the time-harmonic currents included in the respective m-phase alternating currents are controlled in such phases as to be weakened by one another,
• N is equal to 2,
• both of the time-harmonic currents included respectively in the two m-phase alternating currents are in the form of a sine wave, and
• a phase shift of one of the two time-harmonic currents from the other of the two time-harmonic currents is in a range of greater than 120° and less than 240°.

A field winding synchronous machine drive system comprising:

• a field winding synchronous machine including a stator and a rotor, the stator including a stator core and N m-phase stator coils wound on the stator core to create a rotating magnetic field, where N is an integer greater than or equal to 2 and m is an integer greater than or equal to 3, the rotor including a rotor core and at least one main field winding wound on the rotor core to create field magnetic flux;
• and
• a drive apparatus configured to drive the field winding synchronous machine, the drive apparatus including N inverters each of which supplies m-phase alternating current to a corresponding one of the N m-phase stator coils,
• wherein
• each of the inverters supplies the corresponding m-phase stator coil with the m-phase alternating current which includes a fundamental-wave current and a time-harmonic current superimposed on the fundamental-wave current, the time-harmonic current having a shorter period than the fundamental-wave current,
• the rotor core has a plurality of main poles and a plurality of auxiliary poles formed therein, the main poles being formed to protrude toward the stator and circumferentially spaced from one another at a predetermined pitch in electrical angle, the auxiliary poles being formed to protrude toward the stator and circumferentially offset from the main poles by an electrical angle within a predetermined range which includes 90°,
• the rotor includes a plurality of main field windings and a plurality of excitation windings, the main field windings being wound respectively on the main poles of the rotor core and connected in series with each other to create the field magnetic flux, the excitation windings being wound respectively on the auxiliary poles of the rotor core and connected in series with each other to have excitation current induced therein by the time-harmonic currents included in the m-phase alternating currents, and
• the excitation windings are connected with the main field windings via a bridge circuit.