An embodiment relates to a method for operating a three-phase machine including a rotor and a stator connected to a three-phase network. The stator is connected to the three-phase network via a first semiconductor circuit arrangement for forming a first rotational field rotating in a first direction of rotation in the stator and via a second semiconductor circuit arrangement for forming a second rotational field rotating in a direction of rotation opposite to the first direction of rotation in the stator. The three-phase machine further includes a controller. The method includes controlling, via the controller, semiconductors of the first and second semiconductor circuit arrangement to accelerate the rotor by current pulses of both the first rotational field and second rotational field in the first direction of rotation.

An electric motor is disclosed that includes a stator winding defining a plurality of poles, with the winding being controllable to switch between a first number of poles and a second number of poles. A rotor rotatable within the stator includes a first group of magnetic flux barriers being without permanent magnet material and a second group of magnetic flux barriers at least partially filled with a permanent magnet material. A method of operating a line-start electric motor is also disclosed.

An electric motor is disclosed that includes a stator winding defining a plurality of poles, with the winding being controllable to switch between a first number of poles and a second number of poles. A rotor rotatable within the stator includes a first group of magnetic flux barriers being without permanent magnet material and a second group of magnetic flux barriers at least partially filled with a permanent magnet material. A method of operating a line-start electric motor is also disclosed.

A method of manufacturing a rotor of an electric motor or an electric generator includes positioning a plurality of amortisseur bars and using additive manufacturing to place electrically conductive material. More specifically, positioning the amortisseur bars may include circumferentially positioning the bars around a rotor stack and using additive manufacturing to place electrically conductive material may include forming a non-solid pattern of electrically conductive material, such as a pattern of electrically conductive traces, across opposite axial ends of the rotor stack to electrically interconnect an amortisseur circuit.

A rotor for an interior permanent magnet machine (IPM), comprising a rotor core having a plurality of magnetically conductive laminations stacked in a rotor axial direction. The magnetically conductive laminations comprise cut-out portions forming a plurality of flux barriers (FB) radially alternated by flux paths (FP), at least a first part of the flux barriers (FB) housing permanent magnets, at least a second part of the flux barriers (FB) being filled with an electrically conductive and magnetically non-conductive material creating a cage inside the rotor core. The rotor further includes a first and a second short circuit ring positioned at the opposite ends of the rotor core, the first short circuit ring being different from the second short circuit ring.

A rotor for an interior permanent magnet machine (IPM), comprising a rotor core having a plurality of magnetically conductive laminations stacked in a rotor axial direction. The magnetically conductive laminations comprise cut-out portions forming a plurality of flux barriers (FB) radially alternated by flux paths (FP), at least a first part of the flux barriers (FB) housing permanent magnets, at least a second part of the flux barriers (FB) being filled with an electrically conductive and magnetically non-conductive material creating a cage inside the rotor core. The rotor further includes a first and a second short circuit ring positioned at the opposite ends of the rotor core, the first short circuit ring being different from the second short circuit ring.

Core slots are provided in an outer circumferential side of a rotor core and extend in an axial direction of a rotor shaft. A rotor conductor is a rod-shaped conductor inserted in each of the slots, and after insertion of the rotor conductor in each slot, a flared portion is formed flaring in a slot-transverse direction, and a propping-apart force occurring between the flared portion and both side wall surfaces of the slot fixes the rotor conductor to the slot. In an inner wall of an outer circumferential side of each slot abutting the flared portion, an unevenness is arranged along the axial direction of the rotor shaft.

A method of manufacturing a rotor of an electric motor or an electric generator includes positioning a plurality of amortisseur bars and using additive manufacturing to place electrically conductive material. More specifically, positioning the amortisseur bars may include circumferentially positioning the bars around a rotor stack and using additive manufacturing to place electrically conductive material may include forming a non-solid pattern of electrically conductive material, such as a pattern of electrically conductive traces, across opposite axial ends of the rotor stack to electrically interconnect an amortisseur circuit.

A rotor for an LSIPM comprises a plurality of permanent magnets defining a number of poles (P) of the LSIPM, and a plurality of rotor bars spaced about the rotor defining a rotor bar area (BA). The rotor bars are formed of a conductive material having an associated conductivity (.sub.RB). End members are disposed on axial opposite ends of the rotor core. The end members are in electrical contact with the rotor bars. The end members are formed from a material having an associated conductivity (.sub.EM). Each end ring member has a minimum geometric cross sectional area (ERA) and outer diameter that generally corresponds to the rotor core outer diameter. The ERA is greater than 0.5 times the rotor bar area per the number of poles (BA/P) times a ratio of the rotor bar material conductivity to the end member material conductivity (.sub.RB/.sub.EM).

A rotor for an LSIPM comprises a plurality of permanent magnets defining a number of poles (P) of the LSIPM, and a plurality of rotor bars spaced about the rotor defining a rotor bar area (BA). The rotor bars are formed of a conductive material having an associated conductivity (.sub.RB). End members are disposed on axial opposite ends of the rotor core. The end members are in electrical contact with the rotor bars. The end members are formed from a material having an associated conductivity (.sub.EM). Each end ring member has a minimum geometric cross sectional area (ERA) and outer diameter that generally corresponds to the rotor core outer diameter. The ERA is greater than 0.5 times the rotor bar area per the number of poles (BA/P) times a ratio of the rotor bar material conductivity to the end member material conductivity (.sub.RB/.sub.EM).