Segmented electric motor with stator sections and rotor sections with clutches between rotors
Methods and systems are provided for operating an electric motor including multiple rotor and stator sections. In one example, a system may include the multiple rotor sections configured to be mechanically coupled and decoupled from each other concurrently with multiple stator sections configured to be electrically coupled and decoupled from each other, within certain regimes of operation of the electric motor.
1 . A system for an electric motor comprising:
a plurality of rotor sections configured to be mechanically decoupled from one another, wherein the plurality of rotor sections includes two or more of a first rotor section, a second rotor section, and a third rotor section, the plurality of rotor sections being arranged coaxially with an output shaft; and
a plurality of stator sections configured to be electrically decoupled from one another, wherein the plurality of stator sections comprises two or more of a first stator section including three sets of windings electromagnetically interacting with the first rotor section, with each set of windings of the first stator section carrying a single phase of current, a second stator section including three sets of windings electromagnetically interacting with the second rotor section, with each set of windings of the second stator section carrying a single phase of current, and a third stator section including three sets of windings electromagnetically interacting with the third rotor section, with each set of windings of the third stator section carrying a single phase of current, the plurality of rotor sections and the plurality of stator sections enclosed within a common housing;
a first clutch positioned between the first rotor section and the second rotor section configured to mechanically decouple the first rotor section from the second rotor section, and a second clutch positioned between the second rotor section and the third rotor section configured to mechanically decouple the second rotor section from the third rotor section; and
a first set of switches positioned between the first stator section and the second stator section configured to electrically decouple the first stator section from the second stator section, a second set of switches positioned between the second stator section and the third stator section, and a third set of switches configured to form terminal connections for the third stator section, the first set of switches comprises a first switch coupling a first set of windings of the first stator section to a second set of windings of the first stator section and a second switch coupling the second set of windings of the first stator section to a third set of windings of the first stator section, wherein the second set of switches comprises a third switch coupling a first set of windings of the second stator section to a second set of windings of the second stator section and a fourth switch coupling the second set of windings of the second stator section to a third set of windings of the second stator section, and wherein the third set of switches comprises a fifth switch coupling a first set of windings of the third stator section to a second set of windings of the third stator section, and a sixth switch coupling the second set of windings of the third stator section to a third set of windings of the third stator section.
2 . The system of claim 1 , wherein a number of rotor sections of the plurality of rotor sections is equal to a number of stator sections of the plurality of stator sections; wherein each rotor section of the plurality of rotor sections is arranged concentrically within each of a stator section of the plurality of stator sections, each concentric rotor section and stator section pair forming a plurality of motor sections; and wherein a length of each of a motor section of the plurality of motor sections is different.
3 . The system of claim 1 , wherein each of the first set of windings of the first stator section, the first set of windings of the second stator section, and the first set of windings of the third stator section corresponds to a first phase of current; wherein each of the second set of windings of the first stator section, the second set of windings of the second stator section, and the second set of windings of the third stator section corresponds to a second phase of current; and wherein each of the third set of windings of the first stator section, the third set of windings of the second stator section, and the third set of windings of the third stator section corresponds to a third phase of current.
4 . The system of claim 3 , further comprising, a controller including instructions that when executed, cause the controller to:
during operation of the electric motor being within a first region of an efficiency map, operate the electric motor with the third rotor section mechanically coupled to each of the first rotor section and the second rotor section by maintaining each of the first clutch and the second clutch coupled, and with the third stator section electrically coupled to each of the first stator section and the second stator section by maintaining each of the fifth switch and the sixth switch closed and all other switches open, the first region of the efficiency map calibrated as a first function of torque and speed of the electric motor.
5 . The system of claim 4 , wherein the controller includes further instructions to:
during operation of the electric motor being within a second region of the efficiency map, mechanically decouple the third rotor section from each of the first rotor section and the second rotor section by decoupling the second clutch, and electrically decouple the third stator section from each of the first stator section and the second stator section by closing each of the third switch and the fourth switch and opening all other switches, the second region of the efficiency map of calibrated as a second function of torque and speed of the electric motor.
6 . The system of claim 4 , wherein the controller includes further instructions to:
during operation of the electric motor being within a third region of the efficiency map, mechanically decouple each of the third rotor section and the second rotor section from the first rotor section by decoupling the first clutch, and electrically decouple each of the third stator section and the second stator section from the first stator section by closing each of the first switch and the second switch and opening all other switches, the third region of the efficiency map calibrated as a third function of torque and speed of the electric motor.