A hybrid drive system has a battery and a combustion engine for energy sources. The system has a traction motor, a generator, a variable voltage converter (VVC), a motor inverter, a generator inverter, a bus coupling the VVC to the inverters, and a controller. The controller regulates engine speed, motor torque, and generator torque. The engine speed is determined according to a driver torque demand. In normal conditions, 1) the controller regulates the engine speed by modifying a generator torque command, and 2) the bus voltage is regulated using the VVC and battery. When the controller detects a fault in which the battery and VVC become unavailable for regulating the bus voltage, then the controller regulates a motor inverter power output to match a sum of a generator inverter power output and an estimated power loss of the inverters in order to regulate the bus voltage.

An electric power supply system configured to supply electric power to an electrical load device in accordance with a current requirement. The electric power supply system includes an engine configured to output rotational power, a generator configured to receive the rotational power and to supply a current to the electrical load device. The generator includes a rotor, and a stator including a winding and a stator core with the winding wound thereon, a magnetic circuit for the winding passing through the stator core, and a supply current adjustment device configured to adjust magnetic resistance of the magnetic circuit for the winding, to thereby change an inductance of the winding to adjust the supplied current. The electric power supply system further includes a control device configured to control the engine to adjust the output rotational power and to control the supply current adjustment device to adjust the inductance of the winding.

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 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 vehicle is operable in three modes of operation. The vehicle includes a first electromagnetic device, a second electromagnetic device electrically coupled to the first electromagnetic device, and an engine coupled to the first electromagnetic device and configured to drive the first electromagnetic device to provide electrical energy. In each of the three modes of operation, whenever 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 vehicle is operable in three modes of operation. The vehicle includes a first electromagnetic device, a second electromagnetic device electrically coupled to the first electromagnetic device, and an engine coupled to the first electromagnetic device and configured to drive the first electromagnetic device to provide electrical energy. In each of the three modes of operation, whenever 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 vehicle is operable in three modes of operation. The vehicle includes a first electromagnetic device, a second electromagnetic device electrically coupled to the first electromagnetic device, and an engine coupled to the first electromagnetic device and configured to drive the first electromagnetic device to provide electrical energy. In each of the three modes of operation, whenever 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 vehicle is operable in three modes of operation. The vehicle includes a first electromagnetic device, a second electromagnetic device electrically coupled to the first electromagnetic device, and an engine coupled to the first electromagnetic device and configured to drive the first electromagnetic device to provide electrical energy. In each of the three modes of operation, whenever 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 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.