A method of operating a first electric machine and a second electric machine in a vehicle drive includes operating the vehicle drive in a first operating mode by operating the first electric machine to regulate electrical power at a bus to maintain a first voltage on the bus and operating the second electric machine to consume electrical power from the bus. The method includes operating the vehicle drive in a second operating mode by operating the first electric machine to consume electrical power from the bus and operating the second electric machine to regulate electrical power at the bus to maintain a second voltage on the bus. A sum of the electrical power regulated by the first electric machine, the electrical power losses, and the electrical power consumed by the second electric machine is zero in the first operating mode and in the second operating mode.

A drive train for a vehicle includes a first electromagnetic device, a second electromagnetic device electrically coupled to the first electromagnetic device by an electrical power transmission system, and an engine coupled to the first electromagnetic device and configured to drive the first electromagnetic device to provide electrical energy. In all modes of operation where the engine drives the first electromagnetic device to provide the electrical energy, the first electromagnetic device operates without providing the electrical energy to an energy storage device.

A drive train for a vehicle includes a first electromagnetic device, a second electromagnetic device electrically coupled to the first electromagnetic device by an electrical power transmission system, and an engine coupled to the first electromagnetic device and configured to drive the first electromagnetic device to provide electrical energy. In all modes of operation where the engine drives the first electromagnetic device to provide the electrical energy, the first electromagnetic device operates without providing the electrical energy to an energy storage device.

A method is provided for moving off of a vehicle with a hybrid powertrain, comprising a combustion engine; a gearbox with input and output shafts; a first planetary gear connected to the input shaft and a first main shaft; a second planetary gear connected to the first planetary gear and a second main shaft; first and second electrical machines respectively connected to the first and second planetary gears and capable of operating each other; one gear pair connected with the first planetary gear and output shaft; and one gear pair connected with the second planetary gear and output shaft. The method comprising, while the combustion engine is in operation: a) ensuring that the rotatable components of the first and second planetary gears are respectively disconnected from each other, b) ensuring that at least one gear is engaged, corresponding to the one gear pair connected with the first planetary gear, and/or the one gear pair connected with the second planetary gear, and c) activating the first and second electrical machines, where total power output from the electrical machines is zero, and so that a torque is generated in the output shaft.

A vehicle drive includes a gear set, a first motor/generator coupled to the gear set, a second motor/generator at least selectively rotationally engaged with the gear set, and an engine at least selectively coupled to the gear set and at least selectively coupled to the second motor/generator. The second motor/generator is electrically coupled to the first motor/generator by an electrical power transmission system. The first motor/generator and the second motor/generator are electrically coupled without an energy storage device configured to at least one of (a) provide electrical energy to the first motor/generator or the second motor/generator to power the first motor/generator or the second motor/generator and (b) be charged by electrical energy from the first motor/generator or the second motor/generator.

A vehicle drive includes a gear set, a first motor/generator coupled to the gear set, a second motor/generator at least selectively rotationally engaged with the gear set, and an engine at least selectively coupled to the gear set and at least selectively coupled to the second motor/generator. The second motor/generator is electrically coupled to the first motor/generator by an electrical power transmission system. The first motor/generator and the second motor/generator are electrically coupled without an energy storage device configured to at least one of (a) provide electrical energy to the first motor/generator or the second motor/generator to power the first motor/generator or the second motor/generator and (b) be charged by electrical energy from the first motor/generator or the second motor/generator.

A power regeneration system of a work vehicle includes: a first generator (12) and a second generator (31) that are driven by an engine (11); a first electric circuit (C1) for supplying electric power to traveling motors (10L, 10R); a second electric circuit (C2) for supplying electric power to an auxiliary device (35); a voltage step down converter (21) providing electric power from the first electric circuit to the second electric circuit; and a controller (51) that determines whether a travel mode of the work vehicle is a powering mode or a regeneration mode in order to control driving of the voltage step down converter. If the travel mode is the regeneration mode, the controller provides the regenerative power from the first electric circuit through the voltage step down converter to the second electric circuit, in order to drive the auxiliary device with the regenerative power.

A vehicle drive includes a gear set, a first motor/generator coupled to the gear set, a second motor/generator at least selectively rotationally engaged with the gear set, and an engine at least selectively coupled to the gear set and at least selectively coupled to the second motor/generator. The second motor/generator is electrically coupled to the first motor/generator by an electrical power transmission system. The first motor/generator and the second motor/generator are electrically coupled without an energy storage device configured to at least one of (a) provide electrical energy to the first motor/generator or the second motor/generator to power the first motor/generator or the second motor/generator and (b) be charged by electrical energy from the first motor/generator or the second motor/generator.

A vehicle drive includes a gear set, a first motor/generator coupled to the gear set, a second motor/generator at least selectively rotationally engaged with the gear set, and an engine at least selectively coupled to the gear set and at least selectively coupled to the second motor/generator. The second motor/generator is electrically coupled to the first motor/generator by an electrical power transmission system. The first motor/generator and the second motor/generator are electrically coupled without an energy storage device configured to at least one of (a) provide electrical energy to the first motor/generator or the second motor/generator to power the first motor/generator or the second motor/generator and (b) be charged by electrical energy from the first motor/generator or the second motor/generator.

A current supply system configured to receive a rotational driving force and supply a current for driving an electrical load device in accordance with a current requirement. The current supply system includes a rotor, including a permanent magnet, configured to receive the rotational driving force, and a stator including a stator core with a winding wound thereon, a magnetic circuit for the winding passing through the stator core, the rotational driving force causing the rotor and the stator to generate the current. The current supply system further includes a supply current adjustment device configured to change magnetic resistance of the magnetic circuit for the winding in accordance with the current requirement, to thereby change an inductance of the winding to adjust the generated current.