Abstract: The invention relates to a method and a device for operating an asynchronous motor (1) with double feeds, having a stator (1a) connected to a grid and a rotor (1b) connected to an inverter (6), said inverter (6) being designed such that it impresses a target value for an electrical variable in the rotor (1b). In a method according to the invention, after detecting a transient grid voltage change, a target value for the electrical variable determined from at least the rotor flux and the stator flux is impressed in the rotor (1b) such that an active reduction in the torque occurring during the transient grid voltage change is achieved. The target value of the electrical variable is preferably determined from a suitable weighting of the stator flux, rotor flux, stator voltage, stator current, rotor current, and, if available as a measured variable, stator voltage.

Abstract: Provided is a regulator adapted to the various vehicle alternators of the present invention. The regulator particularly includes a coding circuit and a control circuit. The coding circuit is used to provide the different selectable codes. A laser trimming technology is introduced to form an open circuit over the coding circuit, in order to set a code. The control circuit is used to predetermine the various function selections in accordance with the various codes. The coding circuit includes an amplifier, a first input resistor, and a second resistor. The first input resistor is interconnected to a high-voltage end and an input end of the amplifier in series. The second input resistor is further interconnected to the input end and a low-voltage end in series. The open circuit is particularly formed on the first input resistor or the second input resistor for regulating the output voltage and setting a code.

Abstract: An electrical power system may comprise a main generator with a rotor having field windings and at least one embedded permanent magnet. A generator control unit (GCU) may be connected to receive excitation current produced by the main generator with flux from the at least one permanent magnet. An exciter generator may be connected to be provided with excitation from the GCU. The exciter generator may provide excitation current to the field windings of the main generator. The main generator may produce output current from flux from the field windings and the at least one permanent magnet.

Abstract: A field current control circuit for an alternating current generator includes a first voltage source and a time lag reduction circuit, which further includes a generator field that is in selective electrical communication with an energy storage component that is in electrical communication with a time lag reduction voltage source. The time lag reduction circuit may include an electronic controller and be a part of an electric drive machine that receives an operator acceleration command and thereby controls the electrical communication between the energy storage component and the generator field of the time lag reduction circuit. When the energy storage component and generator field are in electrical communication, the current passing through the generator field increases from a starting current to a target current with a reduced time lag compared to predecessor generators.

Abstract: The abnormality detection apparatus includes a first function of measuring a first temperature of a first portion of the abnormality detection apparatus, the first temperature having a correlation with a second temperature of a second portion of a vehicle alternator, a second function of integrating a stress depending on a temperature variation of the first portion on the basis of the first temperature measured by the first function, a third function of predicting occurrence of abnormality in the second portion depending on the stress integrated by the second function, and a fourth function of issuing an alarm when the third function predicts occurrence of abnormality.

Abstract: A power generation controlling device for vehicle includes a communication controlling circuit, a power generation voltage and excitation current controlling circuit, and a communication frame processing circuit. The communication controlling circuit communicates with an ECU using a communication frame. The power generation voltage and excitation current controlling circuit controls power generation based on power generation control information in the received communication frame. The communication frame processing circuit decodes contents of power generation control information (i.e., signal switching data) included in the communication frame based on a signal switching bit in the same communication frame. Two types of contents or more that are switched based on the signal switching bit are assigned to the power generation control information in the communication frame.

Abstract: The disclosed technology is a cryogenic static exciter. The cryogenic static exciter is connected to a synchronous electric machine that has a field winding. The synchronous electric machine is cooled via a refrigerator or cryogen like liquid nitrogen. The static exciter is in communication with the field winding and is operating at ambient temperature. The static exciter receives cooling from a refrigerator or cryogen source, which may also service the synchronous machine, to selected areas of the static exciter and the cooling selectively reduces the operating temperature of the selected areas of the static exciter.

Abstract: An alternator system includes a field circuit, a regulator that regulates a field circuit electrical flow through the field circuit, and an output current sensor that detects an actual current output from the alternator system. The alternator system further includes a controller that communicates with the regulator to vary the field circuit electrical flow based on the actual current detected by the output current sensor.

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: The invention relates to a rapid deexcitation system for synchronous machines (1) with indirect excitation by means of an excitation machine (2) and rotating rectifier bridge (8) comprising: a deexcitation impedance (10) connected between the field winding (5) of the synchronous machine (1) and the rotating rectifier bridge (8); a controller (9) connected in parallel with the deexcitation impedance (10); a control circuit (11) of the controller (9) configured to: keep the controller (9) closed such that the rotating rectifier bridge (8) directly feeds the field winding (5) of the synchronous machine (1) during normal operation of the synchronous machine (1); open the controller (9) such that the deexcitation impedance (10) remains in series with the field winding (5) and with the rotating rectifier bridge (8) when the synchronous machine is to be deexcited.

Abstract: A method of and a system for controlling a permanent magnet AC generator (10), wherein the generator is provided with stator windings and permanent magnets in the rotor and wherein the generator is connected to a drive unit (50), wherein the generator is further provided with a semiconductor converter provided with AC output connected to the generator output and a DC link for controlling the output voltage of the generator, and the converter is further provided with filter means for filtering the output of the converter so that a filtered output of the converter is fed to the generator output.

Abstract: An electric generator with a rotating diode fault detection device built in that operates by comparing a voltage buildup across the exciter DC supply with a preset threshold value and determining if a fault condition is present based on the comparison.

Abstract: A generator unit for a motor vehicle electrical system includes a generator, a first regulator module for regulating the operation of the generator and a digital interface, which is combined with the first regulator module to form one assembly, and includes a program-controlled second regulator module, which is also integrated into the assembly and receives control information via the digital interface.

Abstract: A load control apparatus outputs a PWM signal to a switching element to control a load. The switching element is connected between a power supply and a grand in series with the load. An abnormal increase detecting unit outputs an abnormal increase detection signal when detecting abnormal increase in applied voltage, which is applied to the load, relative to target voltage. An abnormal decrease detecting unit outputs an abnormal decrease detection signal when detecting abnormal decrease in the applied voltage relative to the target voltage. An operating state monitoring unit outputs a normally operating signal when the load normally operates. A signal combining unit generates a combined signal by combining the abnormal increase detection signal, the abnormal decrease detection signal, and the normally operating signal and outputs the combined signal via a common signal output terminal.

Abstract: The disclosure concerns a method for operating a wind turbine having a generator, the generator having for each phase a plurality of coils, wherein the plurality of coils of each phase includes at least one group of coils including at least two coils, the group of coils including at least two subgroups including at least one coil, wherein the generator has a first state in which the coils of the group of coils are electrically connected in series, and, the generator has a second state in which the at least two subgroups are switched electrically in parallel; the method including: changing the state of the generator.

Abstract: A differential gear for an energy production plant, in particular for a wind power plant, has three drives and three power take-offs, whereby a first drive is connected to a drive shaft of the energy production plant, a power take-off is connected to a generator (8), and a second drive is connected to an electric machine (6) as a differential drive. The first drive that is connected to the drive shaft rotates at a basic speed. The speed range of the first drive is at least ?/+6.0% and at most ?/+20.0% of the basic speed, while the electric machine (6) is operated at nominal speed.

Abstract: A frequency converter circuit for a double-fed asynchronous generator with a variable power output, which can be connected to a voltage network contains a rotor rectifier, which can be connected to the rotor of the asynchronous generator, a network frequency converter, which can be connected to the voltage network, and an intermediate circuit. The intermediate circuit contains a semiconductor switch arranged on the rotor rectifier, an intermediate circuit capacitor arranged on the network frequency converter, and a diode arranged between the semiconductor switch and the intermediate circuit capacitor. According to a method for operating such a frequency converter circuit, the semiconductor switch is kept closed during the sub-synchronous operation of the asynchronous generator, and during at least some periods of synchronous or super-synchronous operation of the asynchronous generator the semiconductor switch is opened.

Abstract: An exciter assembly for supplying a field current to the rotor windings of a superconducting synchronous machine includes a pulse transformer having a stationary primary winding, a secondary winding and a tertiary winding. A switched mode power supply supplies a pulsed voltage to the primary winding of the pulse transformer. The pulsed voltage developed at the secondary winding of the pulse transformer is supplied to the rotor windings through a pair of transfer leads. A controller controls synchronous rectification of the pulsed voltage supplied to the rotor windings based on a signal from the tertiary winding of the pulse transformer.

Abstract: With an aim of minimizing excitation losses in electric machines having electrically excited and displaceable secondary parts, bi-directional inductive transmission of energy is carried out by a rotating inductive transmission device. An associated electronic system for the bi-directional transmission of power and/or energy, is provided. Advantageously, super-conductive inductance is present wherein the flow is introduced. It is possible to excite by supplying energy to the stator and to also de-excite by removing energy without converting the power into heat on the rotor by applying a bipolar tension.

Abstract: Output waveform of the generator is improved through stabilization of field current by removing flywheel diode used to be required for automatic voltage regulator. Output electric current of excitation winding 3 is rectified by rectifier 8 and is supplied to field winding 5 of rotor 4. Impedance adjustment circuit 12 is provided to circuit where field current flows. Target electric current determination unit 10 determines target electric current (target field current) used to control output voltage of power generation winding 2 to the reference voltage. Impedance adjustment circuit 12 increases or decreases the impedance of field current circuit so that the field current detected by electric current detector 11 converges with target electric current.

Abstract: A static exciter system (20) for the field winding (17) of a generator (16) which is connected to a grid system via a busbar (19) includes a first device (12, 18, 21) for production of a DC voltage, which is connected to the field winding (17) and together with the field winding (17) form an exciter circuit, as well as a second device (23; 29, C1, . . . , C3) for emission of electrical energy, which second device (23; 29, C1, . . . , C3) briefly feeds additional energy into the exciter circuit when required. An exciter system such as this results in the capability to briefly increase the excitation in a simple, functionally reliable and space-saving manner, by inserting a forward-biased diode (22) into the exciter circuit, and by the capability to connect the second device (23) to the diode (22), in the reverse-bias direction, in order to feed the energy into the exciter circuit.

Abstract: Embodiments provide systems and methods for controlling electronic circuitry. A system can include at least a first controller and a second controller and at least one power electronic circuitry module. The first controller can be in electrical communication with the power electronic circuitry module via a first high-speed serial link (HSSL). The second controller can be in electrical communication with the power electronic circuitry module via a second HSSL.

Abstract: A technique facilitates generation of electric power in well environments. The technique involves combining a cooperating stator and rotor assembly to create an electromagnetic generator. The cooperating stator and rotor assembly utilize an electromagnet which works with a generator coil to create electrical power. Use of the electromagnet enables the electromagnetic field created during generation of electrical power to be selectively eliminated. Elimination of the electromagnetic field allows magnetic particles to be freely flushed from the electromagnetic generator.

Abstract: A voltage regulator with an adaptive field discharge control system may use the rate of change of the POR voltage, the rate of change of the output current and rate of change of the field current, or any combination of these, as an input. The adaptive field discharge control system may process the inputs, identify an operating condition, such as unbalanced load, overcurrent and overload, and compare reference setpoints against that condition. Conventional field control circuits may be triggered by a fixed POR voltage setpoint for all operating conditions. In addition, conventional field control circuits may trigger field discharge to turn on and off continuously during systems oscillations. To avoid these issues, the adaptive field control circuit of the present invention may include a variable POR voltage setpoint, based upon one or more of the rate of change in the POR voltage, the DC bus voltage, or the percentage of unbalanced load.

Abstract: An exciter assembly for supplying a field current to the rotor windings of a superconducting synchronous machine includes a pulse transformer having a stationary primary winding and a secondary winding that is mounted to the rotor of the superconducting synchronous machine for rotation therewith. A switched mode power supply supplies a pulsed voltage to the primary winding of the pulse transformer. The pulsed voltage developed at the secondary winding of the pulse transformer is supplied to the rotor windings through a rectifier semiconductor device and a pair of transfer leads. The rotor windings and a flywheel semiconductor device are located inside a cryogenic chamber or cryostat. The flywheel semiconductor device is connected in parallel with the rotor windings and operates in unison with the rectifier semiconductor device in order to provide synchronous rectification of the switched mode power supply output.

Abstract: Disclosed is a pole count changing generator capable of altering the number of poles contained within a generator. This pole count change is accomplished by changing the path through which electrical current is capable of traveling in response to a control signal sent to a pole count changing circuit.

Abstract: A dual source electric power generating system (EPGS) provides both a regulated AC output and a regulated DC output. The EPGS includes a rotating portion and a stationary portion. The stationary portion includes a plurality of windings (permanent magnet generator (PMG) armature windings, an exciter field winding, and high-voltage main generator armature windings), a voltage regulator, a rectifier, an inverter, a point of regulation (POR) sensor. The high-voltage main generator armature windings generate a high-voltage AC that is converted to a regulated, high-voltage AC by the rectifier and the inverter. The stationary portion is further characterized by circuitry for producing the regulated DC output from AC voltage produced by a winding other than the high-voltage main generator armature windings.

Abstract: An electric circuit is described for generating electric power. In this circuit, an asynchronous generator includes a stator and a rotor. On the stator side, the asynchronous generator is coupled to a power grid. The rotor current flowing to the rotor of the asynchronous generator can be measured. A control device is designed such that, in case of a fault in the power grid, the stator current flowing to the stator of the asynchronous generator is calculated from the measured rotor current as a function of parameters of the asynchronous generator.

Abstract: The vehicle-use power generation control apparatus includes a first section to control an excitation current of a vehicle generator driven by a vehicle engine such that a power generation voltage of the vehicle generator is kept at a first set value, a second section to perform gradual excitation control in order to gradually increase the excitation current, a third section configured to inhibit the gradual excitation control when the power generation voltage falls below a second set value lower than the first set value while the gradual excitation control is performed, a fourth section to detect a rotational speed of the vehicle engine or the vehicle generator, a fifth section to determine a limit value of the excitation current based on the detected rotational speed, and a sixth section configured to limit the excitation current below the limit value when the power generation voltage falls below the second set value.

Abstract: A system and method are provided to isolate outputs of parallel converter threads of a power system converter on a generator side of a wind turbine generator by utilizing isolated power windings on the wind turbine generator. Such isolation eliminates the circulating common mode current between the parallel converters of the wind turbine system and eliminates the need for a common mode inductor. System reliability is enhanced and total system cost is reduced.

Abstract: An embodiment of the present invention may seek to match the generator and grid voltages before the powerplant machine reaches the grid matching speed during the start-up process. An embodiment of the present invention may provide a predictive algorithm, or the like, to control the acceleration rate of the powerplant machine to target a particular phase angle differential between the powerplant machine and the grid when the powerplant machine reaches the grid matching speed. Here, the phase angle difference may be targeted such that a generator breaker may be closed immediately after the powerplant machine accelerates beyond the grid matching speed. This may avoid the generator experiencing a phase angle differential, which may add to the power transient associated with the generator breaker closure.

Abstract: When driven by a variable speed prime mover, a 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 and located in a common core as the main rotor windings to provide two-phase excitation current to the main rotor windings. The exciter stator winding is also located in a common core as the main generator stator 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 and rotor position of the generator, to maintain a constant output frequency.

Abstract: A power generation control apparatus of a rotating electrical machine for a vehicle is obtained which achieves load response control in a plurality of electric power generation control modes even if a generation voltage final target value rapidly changes. The apparatus includes a power control unit 103 and a storage battery 104 connected to a rotating electrical machine 102, and a rotation speed detection part 105 for detecting a rotational speed Na. The power control unit 103 controls power generation in a first mode when the rotational speed Na during operating as a generator is less than or equal to a predetermined value, and controls power generation in a second mode when the rotational speed Na is higher than the predetermined value.

Abstract: A power generation controller for controlling a power generation voltage of a generator; the power generation controller including a warning unit that warns about a start of a high-power load, a power generation voltage setting unit that sets a target of the power generation voltage of the generator and switches the target from a first voltage corresponding to a normal-power load to a second voltage that is higher than the first voltage when a warning is received from the warning unit, and an excitation current controller that controls an excitation current of the generator so that the power generation voltage of the generator becomes the first voltage when the target is the first voltage, and controls the excitation current of the generator so that the power generation voltage of the generator becomes the second voltage when the target is switched to the second voltage.

Abstract: A generator control unit (GCU) provides active damping of a synchronous generator by monitoring the speed of the synchronous generator and detecting oscillations in the monitored speed. The oscillations are indicative of torsional oscillations within the mechanical drivetrain including the synchronous generator or generators. In response to detected oscillations in the monitored speed, the GCU generates a varying set-point value that is used to control the excitation voltage provided to the synchronous generator. Varying the excitation voltage provided to the synchronous generator causes a variation in synchronous generator torque. By selectively varying the torque in the synchronous generator, the GCU provides active damping in the synchronous generator that decreases or dampens the torsional oscillations.

Abstract: A permanent magnet machine (PMM) has a kinetic portion electrically coupled to a power conversion portion. Motive power is provided to the kinetic portion by a torque applied to a motive shaft coupled to a prime mover, such as an aircraft engine or an automobile engine. A control circuit includes a switch disposed between the kinetic portion and output feeder cables of the power conversion portion. A first sensor is effective to detect a first fault condition in either the feeder cables or the power conversion portion and a second sensor is effective to detect a second fault condition in the kinetic energy portion. The first sensor is effective to open the switch when a first fault condition is detected and the second sensor is effective to apply a voltage to a winding within the kinetic portion generating an opposing counter torque on the motive shaft where a combination of torque and counter torque exceeds a fracture yield strength of said motive shaft causing it to fracture.

Abstract: A system for controlling torque ripple in a permanent magnet synchronous machine includes a power converter configured to be coupled to the permanent magnet synchronous machine and to receive converter control signals and a system controller coupled to the power converter. The system controller includes a fundamental current controller configured for providing fundamental voltage commands, a harmonic current controller configured for using harmonic current commands, current feedback signals from the permanent magnet machine, and fundamental current commands in combination with positive and negative sequence regulators to obtain harmonic voltage commands, and summation elements configured for adding the fundamental voltage commands and the harmonic voltage commands to obtain the converter control signals.

Abstract: A stator assembly for use in a superconducting generator operated at frequencies up to 10 Hz is disclosed. The stator assembly includes a ferromagnetic stator winding support having a plurality of teeth defining slots, the slots configured to receive and support stator windings. The stator winding support is formed so that the ratio of the sum of the widths of the slots to the sum of the widths of the teeth and slots is in the range of 0.65 to 0.90.

Abstract: A protection circuit for a wind turbine generator that includes a PWM Brake that works in conjunction with known Brake Relays is disclosed. The Brake Relay is used to short the generator output terminals at a first threshold voltage. The PWM Brake includes one or more switching devices, coupled across the generator output. The PWM Brake is under the control of a PWM Brake Control Circuit which actuates the PWM Brake at a second threshold voltage that is relatively lower than the first threshold voltage. In accordance with an important aspect of the invention, the PWM Brake Control Circuit includes a novel speed sensing circuit for providing a signal representative of the speed of the turbine generator The novel speed sensing circuit eliminates the need to mount a speed sensor on the pole top mounted turbine generator. As such, the need for adding cabling from the pole top mounted wind turbine generator is eliminated.

Abstract: An electric power generation system has a synchronous machine, a starter excitation source and an exciter field driver. The starter excitation source is connected to the synchronous machine via multiple phase connections, and the exciter field driver is connected to the synchronous machine via a portion of the same phase connections. At least one of the phase connections is connected to each other phase connection via a transient voltage suppressor.

Abstract: A generator control unit (GCU) provides active damping of a synchronous generator by monitoring the speed of the synchronous generator and detecting oscillations in the monitored speed. The oscillations are indicative of torsional oscillations within the mechanical drivetrain including the synchronous generator or generators. In response to detected oscillations in the monitored speed, the GCU generates a varying set-point value that is used to control the excitation voltage provided to the synchronous generator. Varying the excitation voltage provided to the synchronous generator causes a variation in synchronous generator torque. By selectively varying the torque in the synchronous generator, the GCU provides active damping in the synchronous generator that decreases or dampens the torsional oscillations.

Abstract: The invention relates to a double-fed asynchronous generator, which is provided with a slipring rotor (1b), and to a method for its operation. In the normal manner, the asynchronous generator has a machine-side converter (5) and a network-side converter (6). According to the invention, the asynchronous generator is designed to supply short-circuit power in that at least one machine-side rotor current (iRM) is maintained in the event of a short circuit, in order to allow the formation of a stator-side short-circuit current. In order that inherent short-circuit currents in sensitive components of the converters (5, 6) are nevertheless avoided, at least the machine-side rotor current (iRM) is maintained in such a way that the actual rotor current (iRMact) in the event of a short circuit is used as the new nominal value in a control apparatus for the asynchronous generator.

Abstract: A single phase AC generator uses a rotor contained within a stator. The stator has an armature winding and a control winding which is capable of having its magnetic permeability adjusted, thereby limiting the output voltage of the armature winding. The stator additionally has two core sections.

Abstract: A generator control circuit is disclosed. One embodiment provides a first active switching circuit configured to connect a first terminal of an excitation coil either to a first or to a second terminal of a voltage source, a second active switching circuit configured to connect a second terminal of the excitation coil either to the first or to the second terminal of the voltage source, and a generator controller to set the duty cycle of the active switching circuit to rapidly control the current through the excitation coil to an excitation coil current setpoint.

Abstract: A method for managing a power supply system with a variable voltage comprising the following steps: according to an instantaneous rotational speed of a rotating electrical machine, a power supply system output voltage with a variable voltage is set to an optimum output voltage between first and second service voltages in such a way as to maximize the electric power delivered by the electrical machine to an energy storage system; when the instantaneous rotational speed is slower than the nominal rotational speed, the output voltage is set to a first value which is substantially equal to the first service voltage in such a way as to maximize the yield of the transfer of energy from the electrical machine to a load; and when the instantaneous rotational speed is faster than the nominal rotational speed, the output voltage (U) is set to a second value substantially equal to the second service voltage in such a way as to maximize the yield of the transfer of energy from the electrical machine towards the load.

Abstract: A method for operating a reversible polyphase rotating electrical machine (2) in a motor vehicle, which consists in performing the high-level and low-level management of the machine with a remote-control unit (1), which exchanges physical data, via a plurality of links (3), with a power module (20) integrated in or immediately proximate the machine (2). The method and electrical machine may be an alternator-starter.

Abstract: A system and device for providing AC signal. The system includes: an AC generator that outputs an AC output signal and includes an AC rotor that communicates with a shaft that is rotated at a rotation speed; a speed sensor for sensing the rotation speed; and a controller for controlling a magnetic field of the AC generator in response to the rotation speed; wherein the controller comprises a Field Exciter for providing a current to the AC generator so as to control the magnetic field of the AC generator.

Abstract: In a power-generator control apparatus, a control circuit intermittently controls the supply of a field current from a battery to a field winding of a power generator in normal mode so as to adjust power induced in an output winding of the power generator. The control circuit interrupts the supply of the field current from the battery to the field winding in transient mode when a transient voltage occurs. An energy absorbing circuit absorbs magnetic energy stored in the field winding independently of magnetic-energy consumption by a resistance of the field winding itself.

Abstract: A system for utilizing waste heat from a vehicle has a Rankine circuit, and the Rankine circuit includes a fluid machine. A generating unit of the fluid machine has a third rotating body that is disposed coaxially with a first rotating body of a pump unit and a second rotating body of an expansion unit. The fluid machine has a drive shaft that is integrally connected at least to the first rotating body, among the first, second and third rotating bodies, and a power transmission unit that is connected to the drive shaft and transmits external power to the drive shaft.

Abstract: The present invention provides for a static excitation system for a superconducting rotor that comprises multiple brushes (12) in contact with the superconducting rotor winding (6), normally via collector rings and field leads. A power conditioning device (16) is connected to the brushes (12), and an energy storage device (18) is linked to the power conditioning device (16). The power conditioning device provides power from the energy storage device to the superconducting rotor when required, and when power to the superconducting rotor is not required, the power conditioning device takes excess power from the superconducting rotor and stores it in the energy storage device.