Electric drive, method for the operation thereof, and serial hybrid drive train for a motor vehicle

A method for operating an electric drive, the method comprising:

• providing a motor assembly, an output assembly, and a transmission stage, wherein the motor assembly has a plurality of electric machines with motor shafts disposed parallel but not coaxial to one another, wherein the transmission stage is connected to the motor assembly and also connected to the output assembly, wherein the transmission stage has a transmission sun connected to the output assembly and has a plurality of transmission planets each connected to a respective one of the electric machines, wherein the transmission planets are each disposed coaxial with a respective one of the motor shafts, are securely fixed on the respective one of the motor shafts and are disposed in an annular manner around the transmission sun and roll on the transmission sun in a torque-transmitting manner;
• controlling electrical sub-phases of the electric machines with one or more power electronics units connected to one or more electric voltage sources, wherein each of the power electronics units is regulated via a respective regulator, and wherein movement parameters of at least one of the output assembly and the transmission stage are fed back to the respective regulator;
• and
• controlling the electric machines differently in groups.

A serial hybrid drive train for a motor vehicle, comprising:

• an internal combustion engine;
• an electrical energy store;
• an electric drive including a motor assembly with a plurality of electric machines, said electric machines having motor shafts disposed parallel but not coaxial to one another;
• said electric drive further including an output assembly, a transmission stage and one or more power electronics units connected to one or more electric voltage sources, said one or more power electronics units controlling electrical sub-phases of said electric machines, each of said power electronics units being regulated via a respective regulator, wherein movement parameters of at least one of said output assembly and said transmission stage are fed back to said respective regulator;
• at least one of said electric machines being coupled mechanically to said internal combustion engine and electrically to said electrical energy store and being operable as a generator;
• at least one of said electric machines being coupled mechanically to said output assembly and electrically to said electrical energy store and being operable as a motor;
• said transmission stage being connected to said motor assembly and also connected to said output assembly;
• said transmission stage having a transmission sun connected to said output assembly and having a plurality of transmission planets each connected to a respective one of said electric machines, said transmission planets each being disposed coaxial with a respective one of said motor shafts and being securely fixed on said respective one of said motor shafts and being disposed in an annular manner around said transmission sun and rolling on said transmission sun in a torque-transmitting manner;
• and
• said electric machines being controlled differently in groups such that a first group of said electric machines is operable as a motor and a second group of said electric machines is operable as a generator.