Abstract: An electric control unit is used to generate control signals for the alternator-starter assembly on the basis of first information signals representative of a state of the vehicle and a control unit is used to generate control signals for power circuits on the basis of diagnosis signals representative of the state of the alternator-starter assembly. The control signals are generated using the electronic control unit also on the basis of at least one first diagnosis signal, and control signals are generated using the control circuit also on the basis of second information signals from a data communication bus.

Abstract: The invention relates to a method for the start of a power plant installation (10), which comprises a gas turbine (2), a generator (18) coupled to the gas turbine (2), and a frequency converter (27) to feed current into an electrical grid (1). In accordance with the method, during the start of the gas turbine (2), the generator (18) is connected to the electrical grid (1) via the frequency converter (27) before the operating rotational speed of the gas turbine (2) is reached, wherein the frequency converter (27) is controlled such that it generates an output current with the grid frequency. The invention further relates to a power plant installation (10) for the execution of such a method.

Abstract: An engine system for starting a gas turbine engine is provided. The system includes a starter generator coupled to the gas turbine engine and configured to provide torque to the gas turbine engine and a controller coupled to the starter generator and configured to provide a command signal to the starter generator. The starter generator provides the torque to the gas turbine engine based on the command signal, and the controller is configured to command the starter generator at a dwell speed until ignition.

Abstract: A shield of a power cable diverts leakage current to ground. During normal operation, the leakage current is steady. An increase in leakage current can lead to a failure mode of the power cable. Systems and methods are described to measure leakage current with a current transducer, which generates a current signal based on the leakage current, and to process the current signal to provide an output of the health of the power cable.

Abstract: Methods and systems are provided for operating an engine, the engine coupled to a traction alternator for vehicle travelling. In one example, the method includes, in an off-highway vehicle running mode of operation, supplying current from the traction alternator to a traction motor via a traction inverter to propel the vehicle, and, in a starting mode of operation, supplying stored energy from a first energy source and a secondary energy source to the traction alternator to start the engine.

Abstract: Featured is a starter/generator to start a reciprocating engine or generate electrical energy using the engine. The starter/generator includes a plurality of magnetic elements that establish a magnetic flux, each magnetic element being attached to a surface of the crankshaft so the element moves in a prescribed path as the crankshaft rotates; a plurality of stator elements being arranged within the engine so as to be maintained in fixed relation to a corresponding magnetic element as it moves in the prescribed path, and control circuitry being configured and arranged to control the functionality of each stator element. In one mode a stator element is controlled so that movement of the magnetic element by the stator element cause electrical energy to be generated in the respective stator element and so in another mode each stator element/magnetic element combination operates the motor/generator as a motor.

Abstract: A power supply system for a motor vehicle is provided with: a generator that includes a rotor having a field coil and a stator having an armature coil; a rectifier that rectifies AC power generated in the armature coil; an excitation control circuit that takes control of a voltage applied to the field coil; a capacitor that is connected to the DC side of the rectifier, and receives and transfers the rectified power; a battery connected to an electric load of the motor vehicle; a DC-DC converter that is connected between the capacitor and the battery and capable of converting unidirectionally or bidirectionally an input DC voltage into any DC voltage; and a selection switch capable of selecting as a power supply source for the excitation control circuit either the capacitor or the battery.

Abstract: A machine has a housing that includes a plurality of stator coils to be positioned adjacent to a rotor. A switching network includes a plurality of transistors and diodes connected to the coils. A current source inverter is provided by a switching network, a pair of inductors positioned on power rails, and commutating capacitors. The current source inverter and the coils are all positioned within the housing. Power architecture for a vehicle has a source of DC power, which communicates with machines through integrated motor drives. The motor drives include at least three coils positioned adjacent to the rotors for a motor associated with the integrated motor drive. A storage switching network is positioned downstream of the coils, with the storage switching network to be closed to allow power from the coils to drive the rotor, or to be opened to allow power to pass to a local storage component.

Abstract: A control apparatus for a motor-generator includes a stator including multi-phase coils, a rotor, a multi-phase inverter one arm of which includes a switch element and a free-wheeling element, and a power supply connected between a neutral point of the coils and a negative electrode of the inverter. When the switch elements are driven by rectangular wave, the low-side switch element connected to the high-side switch element is subject to PWM switching control while the high-side switch element is off. When a time point, at which the high-side switch element is turned off, is defined as a base point, if ? is defined as a time when switching of the low-side switch element starts, and ? is defined as a time when the switching ends, ?-? is 120 degrees in electrical degree or more, ? is more than 0 degrees, and ? is less than 180 degrees.

Abstract: An apparatus for powering an aircraft by generating power from a pressure spool of a turbine engine. AC power can be extracted from the turbine engine by a generator having an integrated autotransformer unit, and converted to DC power.

Abstract: Provided is a vehicle AC generator for improving working efficiency in assembly, allowing a reduction in the number of components, and the like. The vehicle AC generator includes: a rectifier for rectifying an AC generated by a stator coil into a DC; and a regulator for regulating an AC voltage generated by the stator coil, in which: the regulator includes: a regulator holder; a regulator main body provided inside the regulator holder, the regulator main body being for regulating the AC voltage; a capacitor provided inside the regulator holder, the capacitor being for absorbing a noise generated when the AC is rectified into the DC by the rectifier; and an insulating resin material filling the regulator holder so as to fix the regulator main body and the capacitor.

Abstract: The invention is a starting and generating apparatus for an engine, including: a rotator configured to be used as a generator driven by an engine as well as used as a starter motor for starting the engine; a power transmission mechanism configured to connect the engine with the rotator; a starter drive unit configured to supply an electricity to the rotator to drive the rotator as the starter motor when the engine is to be started; a clutch mechanism configured to shut off a power transmission from the engine to the power transmission mechanism when the engine is to be started; and a clutch control unit configured to bring the clutch mechanism into a connected state when a rotational speed of the rotator has reached a given rotational speed at which the engine can be started.

Abstract: A gas turbine engine arrangement comprises a core engine, a power turbine and a propulsor. The core engine comprises at least one compressor and at least one turbine arranged to drive the at least one compressor and the core engine is arranged in a casing. The power turbine is positioned downstream of the at least one turbine and the power turbine is arranged to drive the propulsor. An electrical machine is arranged upstream of the at least one compressor. The electrical machine comprises a stator and a rotor and the electrical machine comprises a motor/generator. A first clutch selectively connects the rotor of the electrical machine to the power turbine and a second clutch selectively connects the rotor of the electrical machine to the at least one compressor of the core engine.

Abstract: A starting/generating system includes a rotor portion and a stator portion. The stator portion is connected to a DC power source during starting operations and to a DC load during generating operations, and includes a DC link having a first and second DC link bus, a DC link capacitor connected between the DC link buses, and an inverter/rectifier that converts AC power to DC power and vice versa. A switching device is connected in series on the first DC link bus and is controlled by a controller that turns the switching device On and Off to provide various functionality to the starting/generating system.

Abstract: A method for controlling a self-piloted alternator-starter for starting or restarting the thermal engine of an automobile. The alternator-starter includes a rotor rotating in a stator, and a belt for transmitting the torque of the alternator-starter rotor to the crankshaft of the thermal engine. The method includes a first preflux step during which the rotor winding is excited by a preflux electric current, and a second starting step during which the stator windings are excited. The preflux step lasts from 10 to 100 ms so that the transmission belt is tensioned below a degradation tension at the start of the second starting step.

Abstract: An improved system and method for starting an engine of an electric drive machine is disclosed. The method includes supplying electric current from a first energy storage device to inductive windings of a propulsion motor. The method also includes accumulating energy in the inductive windings of the propulsion motor based on a magnetic field created when the supplied electric current flows through the inductive windings. Electrical energy is generated by regulating a first plurality of switches associated with a first inverter to cause a collapse of the accumulated energy in the inductive windings. Such electrical energy is stored in an energy storage device. A controller regulates a second plurality of switches associated with a second inverter to cause a release of the stored electrical energy. The released electrical energy is supplied to a generator to start the engine.

Abstract: A starting system may include a wound-field electric machine with a main generator and an exciter generator. The main generator and the exciter generator may each have stator windings and rotor windings. A shorting switch may be provided for interconnecting the stator windings of the exciter generator together when power is applied to stator windings of the main generator. This may result in starting torque being produced by the exciter generator, which starting torque may be additive to starting torque produced by the main generator.

Abstract: In an inverter generator having a winding wound around a generator unit driven by an engine, a converter connected to the winding and adapted to convert an alternating current outputted from the winding to a direct current, an inverter connected to the converter and adapted to invert the direct current outputted from the converter to an alternating current and output it, and a controller adapted to control operations of the converter and the inverter, a battery is connected to the engine, and the winding includes a first winding and a second winding, such that the controller supplies an output of the battery to one of the first winding and the second winding to rotate the generator unit to start the engine.

Abstract: A power-generation motor control system is a control system that controls a power-generation motor provided with an armature and a magnetic-field winding, and is characterized in that when the power-generation motor is operated as a motor, before a power source energizes the armature, a preliminary excitation current, with the value of which the induction voltage across the armature does not exceed the voltage of the power source, is applied to the magnetic-field winding in accordance with the rotation speed of the power-generation motor so that preliminary excitation of the power-generation motor is performed.

Abstract: A hybrid engine installation (200) includes drive element (204) suitable for driving a mechanical element (BTP, BTA) in rotation. In addition, the hybrid engine installation is remarkable in that it includes at least one gas turbine (253, 254) and at least one electric motor (201) mechanically linked to the drive element (204) to drive it in rotation.

Abstract: A turbine engine starter-generator including a main electrical machine including a stator and rotor with a wound rotor inducer and damper bars forming a cage, and an exciter including a stator inducer and rotor with rotor windings connected to the rotor inducer of the main electrical machine via a rotary rectifier. During a first starting stage, the electrical machine operates in asynchronous motor mode by injecting AC into its stator windings, a starting torque being generated by the damper bars, without the rotor inducer of the main electrical machine contributing significantly to generating starting torque. Then in a second starting stage, the main electrical machine operates in synchronous motor mode by injecting AC into its stator windings, while feeding its rotor inducer with DC via the exciter, the change from the first stage to the second stage taking place when rotation speed of the shaft reaches a predetermined value.

Abstract: A system, in one embodiment, may include a static starter subsystem having detection logic for indicating a conductive state of a solid state semiconductor device. The detection logic includes a first logic gate having a first input that receives a first input signal indicating a state of the static starter subsystem, a second input that receives a second input signal indicating a state of a gate firing command being applied to the solid state semiconductor device, and a third input that receives a third input signal indicating whether the solid state semiconductor device is conducting. The first logic gate may be configured to evaluate the first, second, and third input signals and provide a first output signal indicating conductivity of the solid state semiconductor device in response to the gate firing command.

Abstract: A marine power system comprises a motor for providing propulsion. It also comprises an energy storage unit (ESU) for storing and supplying energy to the motor. A prime power system is connected to the ESU and motor for selectively providing energy to these subsystems through a bus. The motor selectively receives energy from the prime power system and the ESU and can supply regenerative braking energy to the bus. The system can also accommodate multiple generator sets providing system power. The ESU can also provide starting power for the prime power system. Alternately, the prime power system drives a mechanical power system output shaft connected to the motor, and the marine system comprises an alternator driven by the prime power system output shaft. The ESU can transmit energy to the alternator. The prime power system can be located on a tugboat displacing a barge carrying the energy storage unit.

Abstract: An electronic control device for a starter-generator or a starter for an internal combustion engine in a motor vehicle has a control and a circuit configuration that includes a pulse-controlled inverter. The control device includes the pulse-controlled inverter, the corresponding control, and a DC/DC converter in one structural unit.

Abstract: Methods and systems are provided for operating an engine, the engine coupled to a traction alternator for vehicle travelling. In one example, the method includes, in an off-highway vehicle running mode of operation, supplying current from the traction alternator to a traction motor via a traction inverter to propel the vehicle, and, in a starting mode of operation, supplying stored energy from a first energy source and a secondary energy source to the traction alternator to start the engine.

Abstract: A power system includes a prime mover drivingly connected to an electric motor/generator. The power system may also include a first electrical energy storage device and a second electrical energy storage device. The power system may further include power-system controls configured to selectively start the prime mover by selectively charging the first electrical energy storage device with electricity from the second electrical energy storage device and transmitting electricity from the first electrical energy storage device to the electric motor/generator to operate the electric motor/generator as an electric motor to start the prime mover.

Abstract: A startup assistance apparatus for a fine pitch Ram Air Turbine (RAT) is provided and includes a generator to provide motive power to the RAT when operating in a first mode and to generate electricity from RAT operation when operating in a second mode and a control unit, including a speed sensing unit configured to sense an operating condition of the generator and a controller operably coupled to the generator and configured to control the generator to operate in the first or the second mode based on the sensed operating condition.

Abstract: The torque transmission system for an aircraft engine permits a starter-generator to drive the engine on starting at a speed reducing ratio. Once the engine is running, the engine then drives the starter-generator also at a speed reducing ratio.

Abstract: A power generation system includes a prime mover, a generator mechanically connected to the prime mover, the generator including a field winding portion and an armature winding portion, a direct current bus node, a first variable frequency drive having an input electrically connected to the bus node and an output electrically connected to the armature winding portion, and an inverter having an input electrically connected to the bus node and an output electrically connected to the field winding portion.

Abstract: A starting and generating system for use with an aircraft engine includes a starter/generator and an inverter/converter/controller (ICC) coupled to the starter/generator. The starter/generator is configured to start the aircraft engine in a start mode and to generate AC power in a generate mode. The starter/generator includes an exciter and a rotational shaft. The ICC is configured to provide AC power at a first frequency the starter/generator in the start mode and to control the exciter during the generate mode such that the generate mode AC power has a second frequency, wherein the first frequency is based on a shaft speed of the shaft.

Abstract: The present invention relates to an electric starting device (1) for an internal combustion engine (5), which electric starting device (1) comprises an electric starter (4) and a starter-generator (2) which is assigned to a traction mechanism drive (3). The starting of the internal combustion engine (5) may take place by means of the electric starter (4) or the starter-generator (2) in each case individually or in a combination of the two units. Also provided is a start-stop device of the internal combustion engine (5), in which a controlled supply of power to the starter-generator (2) is provided in synchronization with a start by means of the electric starter (4).

Abstract: Featured is a starter/generator to start a reciprocating engine or generate electrical energy using the engine. The starter/generator includes a plurality of magnetic elements that establish a magnetic flux, each magnetic element being attached to a surface of the crankshaft so the element moves in a prescribed path as the crankshaft rotates; a plurality of stator elements being arranged within the engine so as to be maintained in fixed relation to a corresponding magnetic element as it moves in the prescribed path, and control circuitry being configured and arranged to control the functionality of each stator element. In one mode a stator element is controlled so that movement of the magnetic element by the stator element cause electrical energy to be generated in the respective stator element and so in another mode each stator element/magnetic element combination operates the motor/generator as a motor.

Abstract: A synchronous electric machine operates as a starter-generator for an aircraft. When operating in a starting mode, a main stator of the machine is supplied with electrical power at a constant frequency. An exciter stator is supplied with variable frequency power. As rotational speed increases, the exciter variable frequency changes correspondingly to maintain synchronous operation of the machine and maximum torque. In a generator mode, variable frequency is applied to the exciter stator with the exciter frequency varying as a function of rotational speed of an engine driving the machine. This provides for a constant frequency output from the machine.

Abstract: A starting system may comprise a wound-field electric machine with a main generator and an exciter generator. The main generator and the exciter generator may each have stator windings and rotor windings. A shorting switch may be provided for interconnecting the stator windings of the exciter generator together when power is applied to stator windings of the main generator. This may result in starting torque being produced by the exciter generator, which starting torque may be additive to starting torque produced by the main generator.

Abstract: A generator system is configured to supply two phase excitation current from an exciter rotor to a main generator rotor. When driven by a variable speed prime mover, the generator system provides relatively constant frequency AC power by independently controlling the main rotor flux rotational speed. The generator system includes an exciter stator that induces current in the exciter rotor windings at a desired frequency and phasing. The exciter rotor windings are electrically connected to the main rotor windings to provide two-phase excitation current to the main rotor windings. Excitation is supplied to the exciter stator from an exciter controller, which controls the frequency and phasing of the exciter excitation, based on the rotational speed of the generator, to maintain a constant output frequency.

Abstract: Usability is improved and noise and fuel consumption are lowered by preventing stopping of a generator output. A hybrid power generator 1 includes a battery 4, an alternator 3, a rectifier unit 51, a DC-DC converter 9 stepping up an output of the battery 4, and an inverter unit 53 converting outputs of the rectifier unit 51 and the DC-DC converter 9 to AC and outputting the AC as a generator output. At a time when a load output reaches an upper limit of an allowable power range of the DC-DC converter 9, the engine 2 is started and power supplying from the battery 4 is switched to power generation by the alternator 3. A generated power restricting unit 27 suppresses the output of the inverter unit 53 during the starting of the engine so that the generator outputs allowable power range of the DC-DC converter 9.

Abstract: A method and system for an engine starter/generator is provided. The starter/generator system includes a three phase squirrel cage induction machine, a three phase inverter/converter electrically coupled to the three phase squirrel cage induction machine. The starter/generator system also includes a bidirectional DC-DC converter electrically coupled to the three phase inverter/converter, and a digital control board configured to sensorlessly determine a rotor angle from a plurality of phase currents to the induction machine during a start mode. During the start mode, logic in the digital control board configures the starter/generator system into a combination of an induction motor, a three phase DC-AC inverter, and a DC-DC boost converter, and during a generate mode, the logic in the digital control board configures the starter/generator system into a combination of an induction generator, a three phase AC-DC converter, and a DC-DC buck converter.

Abstract: A method and device for controlling the starting time of a vehicle mounted thermal engine coupled mechanically to a polyphase rotary electrical machine with an inductor. The electrical machine includes phase windings and sensors for the position of a rotor, and is connected to an on-board electrical network. The method uses pre-fluxing by establishing an excitation current in the inductor for a predetermined pre-fluxing time, before establishment of phase currents. These phase currents are controlled by signals phase-shifted by an angle which varies according to a speed of rotation of the electrical machine, relative to synchronisation signals produced by the sensors. During the starting time, the angle of phase-shifting is additionally dependent on a voltage of the on-board electrical network, in a range contained between a first and second voltages, with the second voltage being higher than the first. In the method, the starting time is independent from the voltage of the on-board electrical network.

Abstract: A machine has a housing that includes a plurality of stator coils to be positioned adjacent to a rotor. A switching network includes a plurality of transistors and diodes connected to the coils. A current source inverter is provided by a switching network, a pair of inductors positioned on power rails, and commutating capacitors. The current source inverter and the coils are all positioned within said housing. Power architecture for a vehicle has a source of DC power, which communicates with machines through integrated motor drives. The motor drives include at least three coils positioned adjacent to the rotors for a motor associated with the integrated motor drive. A storage switching network is positioned downstream of the coils, with the storage switching network to be closed to allow power from the coils to drive the rotor, or to be opened to allow power to pass to a local storage component.

Abstract: A four stroke single cylinder combustion engine starting system with an electrical machine is operable as both a generator and a motor. The starting system has a single cylinder four stroke combustion engine. A piston of the engine is coupled to a shaft of the electrical machine. The starting system also has a motor driver having outputs coupled to the electrical machine. A controller is coupled to the driver and an ignition switch is coupled to the controller. In response to the controller receiving an ignition signal from the ignition switch, the driver controls the electrical machine to operate as a motor so that the electrical machine rotates in a reverse direction to move the piston in a reverse stroke cycle. After the piston reverses to a power stroke position of the reverse stroke cycle the driver controls electrical machine to rotate in a forward direction to move the piston in a forward stroke cycle to attempt to ignite the combustion engine.

Abstract: A synchronous electrical machine comprises a plurality of phases and detecting means arranged to detect an open-circuit fault in at least one of the phases of the synchronous electrical machine. Isolating means is arranged to isolate the at least one phase of the synchronous electrical machine with the fault. Phase shift means are arranged to produce a controlled phase shift between the voltage and the current within the remaining phases of the synchronous electrical machine so as to adjust the phase angle of the second harmonic powers produced by the remaining phases of the synchronous electrical machine such that the vector sum of the second harmonic power vectors of the remaining phases of the synchronous electrical machine is zero to eliminate torque ripple. The phase shift means is arranged to adjust the phase angle of all the remaining phases by the same predetermined angle to maximise the torque ripple-free power output of the synchronous electrical machine.

Abstract: In an electrical power system of a diesel powered system having at least one diesel-fueled power generation unit, the electrical power system configurable in a starting mode for cranking the diesel fueled power unit, the electrical power system having a synchronous machine coupled to the diesel-fueled power generation unit, the synchronous machine having a field winding connected in a parallel relationship with a current conditioner, a method for reconfiguring a baseline circuit topology of the electrical power system for controlling a voltage being developed across the field winding including uncoupling the field winding from the parallel relationship with the current conditioner, and coupling the field winding in a series relationship with the current conditioner.

Abstract: The idle-stop restart control system includes: a sensorless synchronous motor-generator which operates as a generator and a starting motor; an induced-signal detecting circuit for detecting an induced signal output from an armature winding; a field drive circuit for controlling energization of a field winding; and a restart control circuit output, to the field drive circuit, a drive signal for controlling the energization of the field winding to amplify the induced signal while calculating the number of revolutions and an angular position of a rotor based on the detected induced signal when an engine stop command is input and a level of the detected induced signal is equal to or less than a predetermined value and output the drive signal for controlling the energization of the armature winding to restart the engine based on the calculated number of revolutions and angular position of the rotor when a restart command is input.

Abstract: An electric control unit is used to generate control signals for the alternator-starter assembly on the basis of first information signals representative of a state of the vehicle and a control unit is used to generate control signals for power circuits on the basis of diagnosis signals representative of the state of the alternator-starter assembly. The control signals are generated using the electronic control unit also on the basis of at least one first diagnosis signal, and control signals are generated using the control circuit also on the basis of second information signals from a data communication bus.

Abstract: An asymmetric hydraulic press electric generator that converts mechanical energy to electrical energy using hydraulic pressure. The generator employs the principle that force acting on a small area can create a much larger force by virtue of hydrostatic pressure and that a large amount of energy can be carried by a small flow of highly pressurized fluid. Given that the device does not use any natural resources to produce electric power, it is a radically new method of generating clean, renewable energy. This innovative technology aims to change the current destructive cycle of energy production into a constructive cycle that benefits all.

Abstract: A system is provided for measuring the rotational velocity of the rotor of an electric motor or generator having (i) a stator with a plurality of circumferentially spaced pole pieces, each pole piece having a corresponding armature winding, and (ii) a rotor with a plurality of circumferentially spaced magnet portions, the armature windings interacting with the magnetic field produced by the magnet portions. The system includes one or more voltage sensing coils. The or each voltage sensing coil is adapted to encircle a respective pole piece of the stator such that a time-varying electromotive force is induced in the voltage sensing coil as the magnet portions of the rotor pass by the pole piece. The system further includes is a detector for detecting the time-varying electromotive force induced in the or each voltage sensing coil, and determining the rotational velocity of the rotor from the time between peaks in the induced electromotive force.

Abstract: A synchronous electric machine operates as a starter-generator for an aircraft. When operating in a starting mode, a main stator of the machine is supplied with electrical power at a constant frequency. An exciter stator is supplied with variable frequency power. As rotational speed increases, the exciter variable frequency changes correspondingly to maintain synchronous operation of the machine and maximum torque. In a generator mode, variable frequency is applied to the exciter stator with the exciter frequency varying as a function of rotational speed of an engine driving the machine. This provides for a constant frequency output from the machine.

Abstract: A pre-charge circuit limits in-rush currents on a direct current (DC) link that includes a first DC link bus and a second DC link bus. The pre-charge circuit includes a switching device connected in series with the first DC link bus. The switching device has an ON state in which power flow is enabled on the DC link and an OFF state in which power is disabled on the DC link. A controller selectively modulates the state of the switching device to limit in-rush currents on the DC link.

Abstract: A backup power system is connected in parallel to a load, which is powered via a power line connecting that load to a main power source, such as a utility. The backup system includes a generator/condenser unit that is coupled to a flywheel unit to maintain the flywheel of that flywheel unit rotating at a preset speed during normal power system operation and is also connected to a thermal engine to supply power to the load via the generator/condenser unit when there is an interruption of power from the main power source. A shaft-coupling unit couples the generator/condenser unit to the flywheel unit. The shaft-coupling unit includes a sensor plate. When there is a difference in rotational speed between the flywheel and the motor/generator, as would be caused due to a main power unit operating at a level other than a predetermined level, this differential rotational speed is translated by the coupling unit into linear movement of the sensor plate.

Abstract: The invention relates to a method for controlling a reversible electrical machine (14) coupled to a heat engine (13). The electrical machine comprises a field winding (18) which is fed by an excitation current and an armature comprising a plurality of phase windings (22) fed by phase currents. According to the invention, the excitation current of the electrical machine is controlled according to the instantaneous rotational speed of the machine and the torque of the heat engine. According to other characteristics, the excitation current is equal to a pre-determined nominal current when the torque of the engine is resistant and the instantaneous speed is slower than a first pre-determined rotational speed, and is weaker than the nominal current when the torque of the engine is driving or the instantaneous speed is faster than the first speed.