Drive system and method for charging of a battery of a hybrid vehicle

A drive system for a vehicle comprising:

• a combustion engine including an output shaft;
• a motor control configured to control a rotation speed of the combustion engine and the output shaft;
• a gear box including an input shaft;
• an electric machine which comprises a stator and a rotor;
• an energy storage connected to the electric machine;
• a planetary gear which comprises a sun wheel, a ring wheel and a planet wheel holder;
• the output shaft of the combustion engine is connected to a first one of the sun wheel, the ring wheel and the planetary wheel holder of the planetary gear such that rotation of the output shaft causes rotation of the first component, the input shaft of the gear box is connected to a second one of the sun wheel, the ring wheel and the planet wheel holder of the planetary gear such that rotation of the input shaft causes rotation of the second component, and the rotor of the electric machine is connected to a third one of the sun wheel, the ring wheel and the planet wheel holder of the planetary gear such that rotation of the rotor causes rotation of the third component;
• a control unit configured to receive information concerning a charge level of the energy storage, to determine if the charge level of the energy storage is lower than a limit level at which the energy storage has a charging need, and the motor control is configured to control the combustion engine to provide an increased rotation speed compared to a rotation speed of the engine when the energy storage does not have a charging need, when the charge level is below the limit level.