A heat pump apparatus includes a compressor compressing a refrigerant, a motor driving the compressor, an inverter device, and an inverter control unit controlling the inverter device. The inverter device includes the same number of bridge circuits as those of phases of the motor, and each of the bridge circuits includes plural pairs of series-connected switching elements. The pairs of switching elements are connected in parallel. The inverter device applies to the motor a high-frequency voltage of a frequency at which the motor does not rotate.

An electric oil pump constructed by integrally combining an electric motor with an oil pump, wherein the electric motor is composed of a motor casing, a drive shaft that is disposed in a motor housing chamber formed inside the motor casing and is rotatably supported, a rotor that is disposed on the drive shaft, and a stator that is located inside the motor housing chamber and is attached to the motor casing. The electric oil pump is equipped with an internal controller that controls application of electric power to the stator so as to cause the drive shaft to be driven to rotate via the rotor.

An electric oil pump constructed by integrally combining an electric motor with an oil pump, wherein the electric motor is composed of a motor casing, a drive shaft that is disposed in a motor housing chamber formed inside the motor casing and is rotatably supported, a rotor that is disposed on the drive shaft, and a stator that is located inside the motor housing chamber and is attached to the motor casing. The electric oil pump is equipped with an internal controller that controls application of electric power to the stator so as to cause the drive shaft to be driven to rotate via the rotor.

A method for heating a motor vehicle having a three-phase electric motor as a traction motor includes providing a pulse-controlled inverter for supplying power to the electric motor and providing a coolant circuit for cooling the electric motor and the pulse-controlled inverter using coolant, the coolant circuit using the coolant to supply heat to a heat exchanger for heating a passenger compartment and/or a vehicle battery, wherein when the electric motor is stationary, a positive d current and/or negative d current is controlled in a d-axis, with the result that heat loss is generated, the heat loss being introduced into the coolant.

A method and apparatus for controlling transmission oil temperature are provided. The transmission oil is heated using a motor coil of an electric oil pump (EOP) as a heater before a startup of a vehicle. The method includes applying a current to the motor coil of the EOP configured to operate a transmission of the vehicle to thus heat the transmission oil by heat generated from the motor coil.

An apparatus and method for extending component life in a motor drive having a stator heating mode is disclosed. The current supplied to stator windings is cycled through a set of primary stator power transistors to increase the overall lifespan of the drive, thus preventing premature failure of the stator power transistors by splitting the workload between them, rather than having a single transistor supply the bulk of the stator heating current.

A compressor driving apparatus and an air conditioner including the same, whereby the compressor driving apparatus includes a capacitor connected to a DC terminal, an inverter, including a plurality of three-phase switching devices, to convert DC power from the capacitor into AC power to drive a compressor motor, an output current detector to detect output current flowing in the motor, and a controller to output a switching control signal for controlling the inverter based on the output current, wherein the controller performs control such that some of the three-phase switching devices in the inverter are turned on or off in a compressor preheating mode.

An electric traction machine, a motor vehicle, and a method for controlling dissipated heat in the electrical power plant of the motor vehicle are described herein. The power plant is supplied with a current, where, in order to provide a predetermined amount of dissipated heat, a ratio between a field-forming and a torque-forming current deviating from an optimum ratio for a respective operating point of the power plant is prescribed. The predetermined dissipated heat is provided by a power plant embodied as a magnet-less three-phase alternator while a rotor current flowing through a rotor of the three-phase alternator is adjusted, the field-forming and the torque-forming currents being prescribed such that acoustic interference signals of the three-phase alternator are minimized by the ratio, and the rotor current is adjusted such that the predetermined dissipated heat is provided by a combination of the rotor current and the ratio minimizing the interference signals.

An electric drive unit for a motor vehicle includes an electrical machine having a stator and a rotor. An inverter having a first switch unit energizes a first phase system (U, V, W) of the stator. A transmission is connected to the rotor for torque transmission. A lubricant circuit lubricates the transmission and/or cools the rotor. A first cooling circuit cools the first switch unit. A lubricant-coolant heat exchanger thermally couples the first coolant circuit and the lubricant circuit. A control device provides a dissipation-increasing operating mode for the first switch unit in order to increase a dissipation heating a coolant of the first coolant circuit. The lubricant-coolant heat exchanger transfers heat from the heated coolant to the lubricant circuit in order to reduce a viscosity of a lubricant.

An electric drive unit for a motor vehicle includes an electrical machine having a stator and a rotor. An inverter having a first switch unit energizes a first phase system (U, V, W) of the stator. A transmission is connected to the rotor for torque transmission. A lubricant circuit lubricates the transmission and/or cools the rotor. A first cooling circuit cools the first switch unit. A lubricant-coolant heat exchanger thermally couples the first coolant circuit and the lubricant circuit. A control device provides a dissipation-increasing operating mode for the first switch unit in order to increase a dissipation heating a coolant of the first coolant circuit. The lubricant-coolant heat exchanger transfers heat from the heated coolant to the lubricant circuit in order to reduce a viscosity of a lubricant.