Electric generator device with frequency control

Abstract

An electric generator device has: a rotor drivingly engageable by a power source to rotate the rotor at a first rotational speed, a stator positioned opposite to the rotor, a relative rotation between the rotor and the stator generating an alternating electric current, the stator being rotatable; and a transmission assembly having an input drivingly engaged by the power source and an output drivingly engaged to the stator, the transmission assembly providing a speed ratio between the input and the output to cause a rotation of the stator at a second rotational speed different than the first rotation speed.

Description

ELECTRIC GENERATOR DEVICE WITH FREQUENCY CONTROLCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from United States patent application 63 / 582,977 filed on September 15, 2023, the entire contents of which are incorporated by reference herein.TECHNICAL FIELD

[0002] The present application relates to electric power generation and more particularly to the generation of an alternating electric current with a control of frequency.BACKGROUND

[0003] Generators typically include a rotor and a stator so as to produce an alternating current from a power source. In a generator, a relative rotation between an electromagnet and a magnetic field of the stator generates an alternating current that is captured by wiring in the stator, the magnetic field being stationary or rotatable at a lesser speed than that of the electromagnet.

[0004] The generated alternating current is often directed to a network, to appliances, to equipment, such as in domestic uses. In some instances, it is important for the alternating current to have a frequency that matches or corresponds to the frequency of the power network to which it is connected. For instance, some equipment may not respond well to improper frequencies, or frequency variations. Existing generators are satisfactory to some extend, there remains a need for improvements.SUMMARY

[0005] In one aspect, there is provided an electric generator device comprising: a rotor drivingly engageable by a power source to rotate the rotor at a first rotational speed, a stator positioned opposite to the rotor, a relative rotation between the rotor and the stator generating an alternating electric current, the stator being rotatable; and a transmission assembly having an input drivingly engaged by the power source and an output drivingly engaged to the stator, the transmission assembly providing a speed ratio between the input and the output to cause a rotation of the stator at a second rotational speed different thanthe first rotation speed.

[0006] The electric generator device described above may include any of the following features, in any combinations.

[0007] In some embodiments, the transmission assembly includes interconnected rotating members including: an input member drivingly engaged by the input; and an output member drivingly engaging the output and drivingly engaged to the input member, the interconnecting rotating members configured for providing the speed ratio different than one between the input and the output of the transmission assembly.

[0008] In some embodiments, the interconnected rotating members include connecting members, the input member drivingly engaged to the output member via the connection members.

[0009] In some embodiments, the transmission assembly includes a planetary geartrain having: a sun gear; planet gears meshed with the sun gear; a planet carrier rollingly supporting the planet gears; and a ring gear meshed with the planet gears, wherein the input is drivingly engaged to one of the sun gear, the planet carrier, and the ring gear, and the output is drivingly engaged to another one of the sun gear, the planet carrier, and the ring gear.

[0010] In some embodiments, a remaining one of the sun gear, the planet carrier, and the ring gear is non-rotating.

[0011] In some embodiments, the remaining one is the ring gear.

[0012] In some embodiments, the device includes a motor drivingly engaged to the remaining one of the sun gear, the planet carrier, and the ring gear; and a controller operatively connected to the motor, the controller configured for causing a rotation of the remaining one of the sun gear, the planet carrier, and the ring gearwith the motor to change the speed ratio provided by the transmission assembly.

[0013] In some embodiments, the device includes a controller including a processing unit operatively connected to a computer-readable medium having instructions stored thereon executable by the processing unit for: determining that a frequency of a currentgenerated by the electric generator device is different than a desired frequency; and changing the speed ratio of the transmission assembly until the frequency corresponds to the desired frequency.

[0014] In some embodiments, the transmission assembly is a continuously-variable transmission having: an input pulley having input pulley members movable one relative to the other about a rotation axis of the input pulley; an output pulley having output pulley members movable one relative to the other about a rotation axis of the output pulley; and a belt drivingly engaging the input pulley to the output pulley, wherein the transmission assembly is configured for varying an input effective diameter of the input pulley and for inversely varying an output effective diameter of the output pulley to vary the speed ratio.

[0015] In another aspect, there is provided a method for generating an alternating electric current at a desired frequency, using an electric generator device having a rotor and a stator rotating relative to one another, the method comprising: rotating the rotor at a first rotational speed with a power source; transmitting power from the power source to an input of a transmission assembly, the transmission assembly configured to provide a speed ratio between the input and an output; and transmitting power from the output of the transmission assembly to the stator at a second rotational speed different than the first rotational speed.

[0016] The method described above may include any of the following features, in any combinations.

[0017] In some embodiments, the transmission assembly includes a planetary geartrain having: a sun gear; planet gears meshed with the sun gear; a planet carrier rollingly supporting the planet gears; and a ring gear meshed with the planet gears, the transmitting of the power to the input includes transmitting the power to one of the sun gear, the planet carrier, and the ring gear, and the transmitting of the power from the output includes transmitting the power from another one of the sun gear, the planet carrier, and the ring gear.

[0018] In some embodiments, the method includes preventing rotation of a remaining one of the sun gear, the planet carrier, and the ring gear is non-rotating.

[0019] In some embodiments, the preventing of the rotation of the remaining one the remaining one of the sun gear, the planet carrier, and the ring gear includes preventingrotation of the ring gear.

[0020] In some embodiments, the transmission assembly includes a motor drivingly engaged to the remaining one of the sun gear, the planet carrier, and the ring gear, the method comprising causing a rotation of the remaining one of the sun gear, the planet carrier, and the ring gear with the motor to change the speed ratio provided by the transmission assembly.

[0021] In some embodiments, the method includes determining a desired speed ratio between the rotor and the stator; computing a rotational speed of the remaining one of the sun gear, the planet carrier, and the ring gear to achieve the desired speed ratio; and causing rotation of the motor to rotate the remaining one of the sun gear, the planet carrier, and the ring gear at the rotation speed to obtain the desired speed ratio.

[0022] In some embodiments, the causing of the rotation of the remaining one of the sun gear, the planet carrier, and the ring gear includes causing rotation of the ring gear with the motor.

[0023] In yet another embodiment, there is provided an electric generator device comprising: a rotor configured to receive a drive from a power source to rotate at a first rotational speed, a stator positioned opposite to the rotor, such that a relative rotation between rotor and stator generates an alternating electric current, the stator being rotatable; a transmission assembly configured to receive a torque from the power source, the transmission assembly coupled to the stator to cause a rotation of the stator at a second rotational speed; wherein the transmission assembly is adjusted based on the first rotational speed transmitted from the power source to the rotor to maintain a selected rotational speed ratio between first rotational speed and second rotational speed to generate the alternating electric current at a desired frequency.

[0024] The device described above may include any of the following features, in any combinations.

[0025] In some embodiments, the transmission assembly includes interconnected rotating members including: an input member drivingly engaged by the input; and an output member drivingly engaging the output and drivingly engaged to the input member, the interconnecting rotating members configured for providing the speed ratio different than onebetween the input and the output of the transmission assembly.

[0026] In some embodiments, the interconnected rotating members include connecting members, the input member drivingly engaged to the output member via the connection members.

[0027] In some embodiments, the transmission assembly includes a planetary geartrain having: a sun gear; planet gears meshed with the sun gear; a planet carrier rollingly supporting the planet gears; and a ring gear meshed with the planet gears, wherein the power source is drivingly engaged to one of the sun gear, the planet carrier, and the ring gear, and the stator is drivingly engaged to another one of the sun gear, the planet carrier, and the ring gear.

[0028] Therefore, in accordance with the present disclosure, there is provided an electric generator device comprising: a rotor configured to receive a drive from a power source to rotate at a first rotational speed, a stator positioned opposite to the rotor, such that a relative rotation between rotor and stator generates an alternating electric current, the stator being rotatable; a transmission assembly configured to receive said torque from the power source, the transmission assembly coupled to the stator to cause a rotation of the stator at a second rotational speed; wherein the transmission assembly is adjusted based on the first rotational speed transmitted from the power source to the rotor to maintain a selected rotational speed ratio between first rotational speed and second rotational speed to generate the alternating electric current at a desired frequency.

[0029] Further in accordance with the present disclosure, there is provided a method for generating an alternating electric current at a desired frequency, using an electric generator device having a rotor and a stator rotating relative to one another; comprising: coupling a power source to the rotor to impart a rotation to the rotor at a first rotational speed; coupling the power source to the stator via a transmission assembly to impart a rotation to the stator at a second rotational speed; and based on the first rotational speed, adjusting the transmission assembly to maintain a selected rotational speed ratio between first rotational speed and second rotational speed, the selected rotational speed ratio corresponding to generation of an alternating electric current at a desired frequency; and generating the alternating electric current at the desired frequency by operating the power source to drive the rotor at the first rotational speed.BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Fig. 1 is a schematic view of an electric generator device with frequency control in accordance with the present disclosure;

[0031] Fig. 2A is a schematic view of a transmission assembly for the electric generator device of Fig. 1 ;

[0032] Fig. 2B is a schematic view of a transmission assembly in accordance with another embodiment for the electric generator device of Fig. 1 ;

[0033] Fig. 3 is a flowchart illustrating steps of a method for generating an alternating current at a desired frequency; and

[0034] Fig. 4 is a schematic representation of a controller for the electric generator device of Fig. 1 .DETAILED DESCRIPTION

[0035] Referring to the drawings, more particularly to Fig. 1 , an electric generator device with frequency control is generally shown at 10. For simplicity, reference is made herein to an electric generator device 10. The electric generator device 10 is tasked with producing electric power at a desired frequency, hence, the expression “frequency control”. As detailed herein, the frequency control may be passive, i.e., adjusted at set-up, or may be active, i.e., adjusted during operation. The use of this generated power may vary but typically, the electric generator device 10 is connected to a network that will receive the power. However, the electric generator device 10 is not tied to any specific use unless stated otherwise. Accordingly, the present disclosure pertains to the electric generator device 10 being adjusted for its output electric current to have a selected frequency, so as to match that of the power in the network, or to be within acceptable frequency range of any given equipment used with the electric generator device 10. As another possibility, the electric generator device 10 is connected to specific devices, apparatuses or systems that may also require the produced electricity to be at a given frequency. Therefore, the electric generator device 10 described herein is configured to generate electricity at a selected frequency. While the expression “frequency” is used in the singular, the selected frequency includes a frequency range, as there may be variations in frequency as is common in power generation.Moreover, while the following disclosure presents general concepts of the electric generator device 10 and main components thereof, numerous standard components may not be shown, but are included herein. This may include electrical and / or electronic components such as armature, wires, wire coils, copper wiring, electronic regulation components, sensors, ground, insulating components, etc. This may also include mechanical components, such as shafts, bearings, couplers, casings, structures, etc.

[0036] The electric generator device 10 has a generator including a combination of a rotor 11 and a stator 12. Though not shown, the rotor 11 may include electromagnets, etc. The illustration of the rotor 11 is schematic, with various components omitted for simplicity, including the armature. The stator 12 is associated with the stationary magnetic field, though the magnetic field may not be stationary, as the stator 12 rotates as mentioned below. The illustration of the stator 12 is schematic, with various components omitted for simplicity, including the wiring. In Fig. 1 , the rotor 11 is shown as being an internal rotor for the stator 12 being external. In other words, the rotor 11 is located radially inwardly of the stator 12 relative to a rotational axis of the rotor 11 . However, the other arrangement is possible, i.e., with the rotor 11 being external and the stator being internal 12. As is common, the rotor 11 rotates about a given axis and the stator 12 is concentrically positioned relative to the rotor 11. Moreover, in the arrangement of Fig. 1 of the electric generator device 10, the stator 12 also rotates about the given axis. However, the rotational speed (a.k.a., speed, angular speed) of the stator 12 is typically less than that of the rotor 1 1 . The electric generator device 10 is configured to control the rotational speed of the stator 12 relative to that of the rotor 11 so as to maintain a ratio of rotational speeds between that of the rotor 11 and that of the stator 12. By controlling the ratios of speeds, the alternating current produced by the combination of the rotor 11 and of the stator 12 will be at a selected frequency (i.e., selected frequency range).

[0037] The generator is drivingly engaged by a power source A, such a gas turbine engine, an intermittent combustion engine, or any other suitable power source such as a wind turbine, a hydraulic turbine, and so on. The power source A is coupled to the rotor 11 for a torque of the power source A to be transmitted to the rotor 11 . Although the connection between the power source A and the rotor 11 is depicted as a direct engagement, a gearbox or any other suitable transmission may be provided therebetween to change a rotational speed of the rotor 11 relative to that of the power source A. In a variant, the connection is adirect connection with no reduction and no transmission, such that the rotor 1 1 is connected to a shaft driven by the power source A in a 1 :1 ratio. It is also possible to have any appropriate transmission between the engine A and the rotor 11 . Hence, the expression “coupling” encompasses a direct coupling and an indirect coupling, with orwithout reduction, with reduction including speed reduction or speed gain. Thus, torque Ti received by the rotor 11 from the power source A may or may not have been reduced or transmitted when received at the rotor 11 . Therefore, via torque T-i, the rotor 1 1 rotates at speed Vi.

[0038] In order to achieve such ratio, the electric generator device 10 further includes a transmission assembly 20. The transmission assembly 20 receives a mechanical force, such as torque T-i, from an engine / power source A. The engine / power source A may be any appropriate source of motive power. In a first embodiment, the engine / power source A is an engine such as a diesel engine. Other engine / power source examples include a gas turbine engine, a wind turbine, a steam turbine, to name but a few of the motive forces that can drive the electric generator device 10.

[0039] The transmission assembly 20 is configured to receive torque Ti from the power source A. The transmission assembly 20 is coupled to the stator 12 so as to cause rotation of the stator 12. The transmission assembly 20 is tasked with changing the speed of rotation of the stator 12 relative to that the rotor 11 , or causing a relative rotation between the stator 12 and the rotor 11 , for instance by rotating the stator 12 in a different direction than that of the rotor 1 1 . The transmission assembly 20 may be any appropriate transmission assembly having any appropriate configurations. For example, the transmission assembly 20 may be a planetary gear system, an epicyclic gear system or any other gear or pulley arrangement that will cause the reduction or rotational speed ratio, relative rotation. Examples of transmission are provided in Figs. 2A and 2B and described below. As another example, the transmission assembly 20 includes chains and sprockets, gears and pulleys, one or more CVTs, etc. In a variant, the transmission assembly 20 is adjustable, i.e., has the capacity of providing different reduction ratios. For example, in the case of a planetary gear system, different operational arrangements can be actuated to achieve different reduction ratios. Though not shown, the rotor 11 may also be coupled to the transmission assembly 20, though with the capacity for the device 10 to adjust its reduction ratio between rotor 11 and stator 12.

[0040] In the embodiment shown, the transmission assembly 20 is used to increase a speed of the rotor 11 relative to the stator 12. Consequently, when the power source A is an internal combustion engine, said engine may rotate at a lower regime while maintaining the same speed of the rotor 11 relative to the stator 12, which is caused to rotate in an opposite direction than that of the rotor 11 . This may allow a reduction of a fuel consumption of the engine and, consequently, may render the generator more environmentally friendly.

[0041] As a possibility, an engine control unit 14 may be coupled to various components of the electric generator device 10 so as to control the reduction between a drive from the power source A and the stator 12, relative to the rotor 1 1 . In a variant, if the power source A is an engine, it is possible to control its rotational speed. Accordingly, if the engine / power source A has a controllable speed that may be maintained constantly between a given speed range, the transmission assembly 20 may be set up to provide a fixed reduction ratio by which the stator 12 will always be at a given speed relative to that of the rotor 11 . In such an embodiment, the engine control unit 14 may have limited impact as it will not intervene with the transmission assembly 20 once the device 10 is arranged to produce electric current at a desired frequency. The engine control unit 14 may be used to ensure that the engine is at the desired speed and / or may provide switching in order to electrically couple the electric generator device 10 to the network, apparatus or equipment once the power produced is at the desired frequency. Thus, such a control / adjustment is passive, in that the adjustment is made in a set-up phase, and may then only need periodic adjustments.

[0042] For example, the engine / power source A may have two or more different fixed rotational speeds based on different factors (e.g., energy price, etc), with the engine control unit 14 adjusting the transmission assembly 13 to provide the appropriate reduction ratio based on the speed of the engine / power source A.

[0043] In some embodiments, the engine / power source A may produce variable output speeds with the engine control unit 14 controlling the transmission assembly 20 so as to achieve a desired reduction and therefore speed ratio between the rotor 11 and stator 12. If the transmission assembly 20 is a planetary gear system, for example, the engine control unit 14 may be tasked with operating the transmission assembly 20 to achieve such reduction ratio. This may be an active control of the transmission assembly 20.

[0044] The electric generator device 10 may not have such engine control unit 14 as itmay be possible to ensure that the engine / power source A always provides a desired speed. In such a case, the transmission assembly 20 may be set up to provide the appropriate reduction ratio such that, when the engine / power source A is operated at its expected speed, the power generated by the combination of the rotor 11 and the stator 12 is always at the selected frequency. This would result in a simplified system without complex engines control.

[0045] It should be observed that both the rotor 11 and the stator 12 are powered solely with torque from the engine / power source A, the engine / power source A being the sole motive force. Therefore, the electric generator device 10 of Fig. 1 does not require any auxiliary motor or other power source to operate the stator 12.

[0046] Therefore, the electric generator device 10 may be generally described as having a rotor configured to receive a drive from a power source to rotate at a first rotational speed, a stator is positioned opposite to the rotor, such that a relative rotation between rotor and stator generates an alternating electric current, the stator being rotatable. A transmission assembly may be configured to receive said torque from the power source, the transmission assembly coupled to the stator to cause a rotation of the stator at a second rotational speed. The transmission assembly is adjusted based on the first rotational speed transmitted from the power source to the rotor to maintain a selected rotational speed ratio between first rotational speed and second rotational speed to generate the alternating electric current at a desired frequency.

[0047] The electric generator device 10 may be operated according to a method for generating an alternating electric current at a desired frequency, using an electric generator device having a rotor and a stator rotating relative to one another. The method may include coupling a power source to the rotor to impart a rotation to the rotor at a first rotational speed; coupling the power source to the stator via a transmission assembly to impart a rotation to the stator at a second rotational speed; based on the first rotational speed, adjusting the transmission assembly to maintain a selected rotational speed ratio between first rotational speed and second rotational speed, the selected rotational speed ratio corresponding to generation of an alternating electric current at a desired frequency; and generating the alternating electric current at the desired frequency by operating the power source to drive the rotor at the first rotational speed.

[0048] Referring to Fig. 2, an exemplary embodiment of the transmission assembly 20 is shown. The transmission assembly 20 includes a housing 21 that encloses a planetary gear train 22. It will be appreciated that other kinds of gear train may be used without departing from the scope of the present disclosure. The transmission assembly 20 includes an input 20I and an output 200. The input 20I receives a rotational input from the power source A and the output 200 is drivingly engaged to the stator 12 of the generator.

[0049] The planetary gear train 22 includes a sun gear 23 meshed with planet gear 24 disposed circumferentially around the sun gear 23 relative to a rotation axis of the sun gear 23 and a ring gear 25 meshed with the planet gears 24 and disposed therearound. A planet carrier 26 rollingly supports the planet gears 24. The planet gears 24 therefore rotate each about their respective rotation axes and rotate around the rotation axis of the sun gear 23. In the embodiment shown, the input 20I is drivingly engaged to the sun gear 23 and the output 200 is drivingly engaged to the planet carrier 26. Diameters of the gears are selected to provide a speed ratio. Hence, as the sun gear 23 rotates, it induces rotation of the planet gears 24 and of the planet carrier26. The planet carrier 26 rotates at a different (e.g., slower) speed than the sun gear 23. The ring gear 25 may be fixed relative to the housing 21 such that the ring gear 25 do not rotate. However, in an alternate embodiment, the input may be engaged to any one of the sun gear, the planet carrier and the ring gear while the output may be engaged by any other one of the sun gear, the planet carrier and the ring gear. Rotation of a remaining one of the sun gear, the planet carrier and the ring gear may be fixed.

[0050] Therefore, in this configuration, a constant speed ratio is provided by the planetary gear train 22 between the input 20I and the output 200. Consequently, since the power source A induces rotation of both of the rotor 1 1 and of the sun gear 23, these two components rotate at the same speed, and, since the planetary gear train 22 provides a fixed speed ratio between the sun gear 23 and the planet carrier 26, the stator 12 will rotate relative to the rotor 11 also at a constant speed ratio. Consequently, even if the rotational speed of the power source A change, the speed ratio between the rotor 11 and the stator 12 remains constant. This may permit to generate power at a constant frequency while mitigating speed changes of the power source A.

[0051] As previously explained, it may be possible to vary this speed ratio in someembodiments. For instance, in the embodiment shown, a motor 30, such as an electric motor, may be drivingly engaged to the ring gear 25. The motor 30 may be powered by electricity generated by the generator, or by an external source of power, such as a battery. The engine control unit 14 may be operatively connected to the motor 30 to induce rotation of the ring gear 25. The rotation of the ring gear 25 effectively changes a speed ratio provided between the input 20I and the output 200. The engine control unit 14 may be configured to determine the rotational speed of the ring gear 25 to obtain a desired speed ratio between the input 20I and the output 200. In some embodiments, the transmission need not the motor 30 to change the speed ratio. An example of such a transmission is provided below with reference to Fig. 2B.

[0052] The transmission assembly 20 may include any interconnected rotating members, such as gears, sprocket, pulleys, and so on. The rotating members include an input member drivingly engaged by the input 20I and an output member drivingly engaging the output 200 and drivingly engaged to the input member. The interconnected rotating members are configured for providing the speed ratio different than one between the input 20I and the output 200 of the transmission assembly 20. The interconnected rotating members may further include connecting members such that the input member is drivingly engaged to the output member via the connection members. Alternatively, the input member may be directly engaged to the output member (e.g., two gears of different diameters).

[0053] In the case of the planetary gear train 22, the input member is the sun gear 23, the output member is the planet carrier 26, and the connecting members are the planet gears 24 and the ring gear 25. However, any other suitable gearing arrangement may be used without departing from the scope of the present disclosure.

[0054] The disclosed generator may permit to produce electricity at a reduced speed of the power source A (e.g., internal combustion engine). The planetary geartrain 22 may offer a compact installation minimizing size of the generator while reducing speed of the power source while maintaining the same frequency of the generated current.

[0055] Referring now to Fig. 2B, a transmission assembly in accordance with another embodiment is shown at 120. In the embodiment shown, the transmission assembly 120 includes a continuously-variable transmission (CVT) 122. The CVT 122 includes an input pulley 123 engaged by the input 1201 of the transmission assembly 120 and an output pulley124 engaging the output 1200 of the transmission assembly 120. A belt 125 is used to couple the pulleys together. In other words, the input pulley 123 is drivingly engaged to the output pulley 124 via the belt 125. The belt and pulleys are thus another example of interconnecting members of the transmission assembly.

[0056] In the embodiment shown, each of the input pulley 123 and the output pulley 124 includes two pulley members 123A, 124A that are axially movable one relative to the other about respective rotation axes ofthe pulleys. As illustrated, the pulley members 123A, 124A are coned-shaped, or frustoconical and the belt 125 has a tapered shape having two sides contacting the pulley members 123A, 124A. A first actuator 126 is coupled to the input pulley 123 and a second actuator 127 is coupled to the output pulley 124. The first actuator 126 and the second actuator 127 may be replaced by a single actuator in some embodiments. The actuators are operatively connected to the engine control unit 14 and are operable to vary a distance between the respective pulley members 123A, 124A of each of the input and output pulleys 123, 124. The actuators may be solenoid actuators, pneumatic actuators, hydraulic actuators or any other suitable actuators. The transmission assembly 120 is configured for varying an input effective diameter ofthe input pulley and for inversely varying an output effective diameter of the output pulley to change the speed ratio.

[0057] The actuators may be omitted in some embodiments such that the transmission assembly 120 may change the speed ratio passively, that is, without the use of an external force. For instance, the CVT may use centrifugal force to cause the changing ofthe effective diameter of the pulleys. The pulley members may include weights, which may be in sliding engagement with frustoconical members of the pulley members. As the rotational speed increases, the weights move radially outwardly thereby exerting a force on the frustoconical members, which then move toward one another to increase its effective diameter. In some embodiments, oil pressure may be used to exert a force on the pulley members.

[0058] Therefore, if a rotational speed of the output 1200 of the transmission assembly 120 is to be increased, the first actuator 126 biases the pulley members 123A of the input pulley 123 towards one another thereby increasing an effective diameter of the input pulley 123 by forcing the belt 125 to move radially outwardly away from the rotation axis of the input pulley 123. Since the belt 125 has a fixed length, the second actuator 127 causes the pulley members 124A of the output pulley 124 to move away from one another to decreasethe effective diameter ofthe output pulley 124. This permits the belt 125 to ride closerto the rotation axis of the output pulley 124. Hence, the rotational speed of the output 1200 will be greater than that of the input 1201. These steps are performed in reverse if it is desired to reduce the rotational speed of the output 1200 relative to that of the input 1201.

[0059] The engine control unit 14 may further control a rotational speed of the power source A to obtain the desired frequency ofthe generated current. This may be achieved by varying a flow rate of a fuel supplied to the engine.

[0060] Moreover, the transmission assembly 20, 120 may be drivingly engaged to the rotor, between the power source A and said rotor. Therefore, the transmission assembly 20, 120 may be used to increase a rotational speed ofthe rotorto vary the frequency. The stator, in such an embodiment, may remain stationary (i.e., non-rotating).

[0061] Referring to Fig. 3, a method for generating an alternating electric current at a desired frequency is shown at 300. The method 300 includes rotating the rotor 11 at a first rotational speed with the power source A at 302; transmitting power from the power source A to the input 20I of the transmission assembly 20 at 304, the transmission assembly configured to provide a speed ratio between the input 20I and the output 200; and transmitting power from the output 200 of the transmission assembly 20 to the stator 12 at a second rotational speed different than the first rotational speed at 306.

[0062] In some embodiments, the transmitting of the power to the input 20I includes transmitting the power to one ofthe sun gear 23, the planet carrier 26, and the ring gear 25. The transmitting of the power from the output 200 includes transmitting the power from another one of the sun gear 23, the planet carrier 26, and the ring gear 25. In some embodiments, rotation of a remaining one of the sun gear 23, the planet carrier 26, and the ring gear 25 is non-rotating. In some embodiments, the preventing of the rotation of the remaining one of the sun gear 23, the planet carrier 26, and the ring gear 25 includes preventing rotation of the ring gear.

[0063] In some embodiments, the transmission assembly 20 includes the motor 30 drivingly engaged to the remaining one of the sun gear 23, the planet carrier 26, and the ring gear 25. The method 300 may include causing a rotation of the remaining one of the sun gear 23, the planet carrier 26, and the ring gear 25 with the motor 30 to change thespeed ratio provided by the transmission assembly 20.

[0064] More particularly, the method 300 may include determining a desired speed ratio between the rotor 11 and the stator 12; computing a rotational speed of the remaining one of the sun gear 23, the planet carrier 26, and the ring gear 25 to achieve the desired speed ratio; and causing rotation of the motor 30 to rotate the remaining one of the sun gear 23, the planet carrier 26, and the ring gear 25 at the rotation speed to obtain the desired speed ratio. The computation of the rotational speed of the remaining one is based on the diameters of the gears of the transmission assembly. The causing of the rotation of the remaining one of the sun gear 23, the planet carrier 26, and the ring gear 25 includes causing rotation of the ring gear 25 with the motor 30.

[0065] In some embodiments, the method 300 includes receiving an input regarding a frequency of a current generated by the generator and, if the frequency is different than a desired frequency, the engine control unit 14 may cause the transmission assembly 20, 120 to change the speed ratio until the frequency corresponds to the desired frequency. More specifically, the method 300 may include determining that a frequency of a current generated by the electric generator device 10 is different than a desired frequency; and changing the speed ratio of the transmission assembly 20, 120 until the frequency corresponds to the desired frequency.

[0066] With reference to Fig. 4, an example of a computing device 400 is illustrated. For simplicity only one computing device 400 is shown but the system may include more computing devices 400 operable to exchange data. The computing devices 400 may be the same or different types of devices. The controller 14 may be implemented with one or more computing devices 400.

[0067] The computing device 400 comprises a processing unit 402 and a memory 404 which has stored therein computer-executable instructions 406. The processing unit 402 may comprise any suitable devices configured to implement the method XX such that instructions 406, when executed by the computing device 400 or other programmable apparatus, may cause the functions / acts / steps performed as part of the method XX as described herein to be executed. The processing unit 402 may comprise, for example, any type of general-purpose microprocessor or microcontroller, a digital signal processing (DSP) processor, a central processing unit (CPU), an integrated circuit, a field programmable gatearray (FPGA), a reconfigurable processor, other suitably programmed or programmable logic circuits, or any combination thereof.

[0068] The memory 404 may comprise any suitable known or other machine-readable storage medium. The memory 404 may comprise non-transitory computer readable storage medium, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. The memory 404 may include a suitable combination of any type of computer memory that is located either internally or externally to device, for example random-access memory (RAM), read-only memory (ROM), compact disc read-only memory (CDROM), electro-optical memory, magneto-optical memory, erasable programmable read-only memory (EPROM), and electrically-erasable programmable read-only memory (EEPROM), Ferroelectric RAM (FRAM) or the like. Memory 404 may comprise any storage means (e.g., devices) suitable for retrievably storing machine-readable instructions 406 executable by processing unit 402.

[0069] The methods and systems described herein may be implemented in a high level procedural or object oriented programming or scripting language, or a combination thereof, to communicate with or assist in the operation of a computer system, for example the computing device 400. Alternatively, the methods and systems described herein may be implemented in assembly or machine language. The language may be a compiled or interpreted language. Program code for implementing the methods and systems described herein may be stored on a storage media or a device, for example a ROM, a magnetic disk, an optical disc, a flash drive, or any other suitable storage media or device. The program code may be readable by a general or special-purpose programmable computer for configuring and operating the computer when the storage media or device is read by the computer to perform the procedures described herein. Embodiments of the methods and systems described herein may also be considered to be implemented by way of a non- transitory computer-readable storage medium having a computer program stored thereon. The computer program may comprise computer-readable instructions which cause a computer, or more specifically the processing unit 402 of the computing device 400, to operate in a specific and predefined manner to perform the functions described herein, for example those described in the method 300.

[0070] Computer-executable instructions may be in many forms, including program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types. Typically the functionality of the program modules may be combined or distributed as desired in various embodiments.

[0071] The embodiments described herein are implemented by physical computer hardware, including computing devices, servers, receivers, transmitters, processors, memory, displays, and networks. The embodiments described herein provide useful physical machines and particularly configured computer hardware arrangements. The embodiments described herein are directed to electronic machines and methods implemented by electronic machines adapted for processing and transforming electromagnetic signals which represent various types of information. The embodiments described herein pervasively and integrally relate to machines, and their uses; and the embodiments described herein have no meaning or practical applicability outside their use with computer hardware, machines, and various hardware components. Substituting the physical hardware particularly configured to implement various acts for non-physical hardware, using mental steps for example, may substantially affect the way the embodiments work. Such computer hardware limitations are clearly essential elements of the embodiments described herein, and they cannot be omitted or substituted for mental means without having a material effect on the operation and structure of the embodiments described herein. The computer hardware is essential to implement the various embodiments described herein and is not merely used to perform steps expeditiously and in an efficient manner.

[0072] The technical solution of embodiments may be in the form of a software product. The software product may be stored in a non-volatile or non-transitory storage medium, which can be a compact disk read-only memory (CD-ROM), a USB flash disk, or a removable hard disk. The software product includes a number of instructions that enable a computer device (personal computer, server, or network device) to execute the methods provided by the embodiments.

[0073] It is noted that various connections are set forth between elements in the preceding description and in the drawings. It is noted that these connections are generaland, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. A coupling between two or more entities may refer to a direct connection or an indirect connection. An indirect connection may incorporate one or more intervening entities. The term “connected” or "coupled to" may therefore include both direct coupling (in which two elements that are coupled to each other contact each other) and indirect coupling (in which at least one additional element is located between the two elements).

[0074] It is further noted that various method or process steps for embodiments of the present disclosure are described in the preceding description and drawings. The description may present the method and / or process steps as a particular sequence. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the description should not be construed as a limitation.

[0075] Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. As used herein, the terms “comprises”, “comprising”, or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0076] While various aspects of the present disclosure have been disclosed, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the present disclosure. For example, the present disclosure as described herein includes several aspects and embodiments that include particular features. Although these particular features may be described individually, it is within the scope of the present disclosure that some or all of these features may be combined with any one of the aspects and remain within the scope of the present disclosure. References to “various embodiments,” “one embodiment,” “an embodiment,” “an example embodiment,” etc., indicate that the embodiment described may include a particular feature,structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. The use of the indefinite article “a” as used herein with reference to a particular element is intended to encompass “one or more” such elements, and similarly the use of the definite article “the” in reference to a particular element is not intended to exclude the possibility that multiple of such elements may be present.

[0077] The embodiments described in this document provide non-limiting examples of possible implementations of the present technology. Upon review of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made to the embodiments described herein without departing from the scope of the present technology. Yet further modifications could be implemented by a person of ordinary skill in the art in view of the present disclosure, which modifications would be within the scope of the present technology.

Claims

CLAIMS:1 . An electric generator device comprising: a rotor drivingly engageable by a power source to rotate the rotor at a first rotational speed, a stator positioned opposite to the rotor, a relative rotation between the rotor and the stator generating an alternating electric current, the stator being rotatable; and a transmission assembly having an input drivingly engaged by the power source and an output drivingly engaged to the stator, the transmission assembly providing a speed ratio between the input and the output to cause a rotation of the stator at a second rotational speed different than the first rotation speed.

2. The electric generator device of claim 1 , wherein the transmission assembly includes interconnected rotating members including: an input member drivingly engaged by the input; and an output member drivingly engaging the output and drivingly engaged to the input member, the interconnecting rotating members configured for providing the speed ratio different than one between the input and the output of the transmission assembly.

3. The electric generator device of claim 2, wherein the interconnected rotating members include connecting members, the input member drivingly engaged to the output member via the connection members.

4. The electric generator device of claim 1 , wherein the transmission assembly includes a planetary gear train having: a sun gear; planet gears meshed with the sun gear; a planet carrier rollingly supporting the planet gears; and a ring gear meshed with the planet gears, wherein the input is drivingly engaged to one of the sun gear, the planet carrier, and the ring gear, and the output is drivingly engaged to another one of the sun gear, the planet carrier, and the ring gear.

5. The electric generator device of claim 4, wherein a remaining one of the sun gear, the planet carrier, and the ring gear is non-rotating.

6. The electric generator device of claim 5, wherein the remaining one is the ring gear.

7. The electric generator device of claim 4, comprising: a motor drivingly engaged to the remaining one of the sun gear, the planet carrier, and the ring gear; and a controller operatively connected to the motor, the controller configured for causing a rotation of the remaining one of the sun gear, the planet carrier, and the ring gear with the motor to change the speed ratio provided by the transmission assembly.

8. The electric generator device of claim 1 , comprising a controller including a processing unit operatively connected to a computer-readable medium having instructions stored thereon executable by the processing unit for: determining that a frequency of a current generated by the electric generator device is different than a desired frequency; and changing the speed ratio of the transmission assembly until the frequency corresponds to the desired frequency.

9. The electric generator device of claim 1 , wherein the transmission assembly is a continuously-variable transmission having: an input pulley having input pulley members movable one relative to the other about a rotation axis of the input pulley; an output pulley having output pulley members movable one relative to the other about a rotation axis of the output pulley; and a belt drivingly engaging the input pulley to the output pulley, wherein the transmission assembly is configured for varying an input effective diameter of the input pulley and for inversely varying an output effective diameter of the output pulley to vary the speed ratio.

10. A method for generating an alternating electric current at a desired frequency, using an electric generator device having a rotor and a stator rotating relative to one another, the method comprising: rotating the rotor at a first rotational speed with a power source; transmitting power from the power source to an input of a transmission assembly, the transmission assembly configured to provide a speed ratio between the input and an output; and transmitting power from the output of the transmission assembly to the stator at a second rotational speed different than the first rotational speed.

11. The method of claim 10, wherein the transmission assembly includes a planetary geartrain having: a sun gear; planet gears meshed with the sun gear; a planet carrier rollingly supporting the planet gears; and a ring gear meshed with the planet gears, the transmitting of the power to the input includes transmitting the power to one of the sun gear, the planet carrier, and the ring gear, and the transmitting of the power from the output includes transmitting the power from another one of the sun gear, the planet carrier, and the ring gear.

12. The method of claim 11 , comprising preventing rotation of a remaining one of the sun gear, the planet carrier, and the ring gear is non-rotating.

13. The method of claim 12, wherein the preventing of the rotation of the remaining one the remaining one of the sun gear, the planet carrier, and the ring gear includes preventing rotation of the ring gear.

14. The method of claim 11 , wherein the transmission assembly includes a motor drivingly engaged to the remaining one of the sun gear, the planet carrier, and the ring gear, the method comprising causing a rotation of the remaining one of the sun gear, the planet carrier, and the ring gear with the motor to change the speed ratio provided by the transmission assembly.

15. The method of claim 14, comprising: determining a desired speed ratio between the rotor and the stator; computing a rotational speed of the remaining one of the sun gear, the planet carrier, and the ring gear to achieve the desired speed ratio; and causing rotation of the motor to rotate the remaining one of the sun gear, the planet carrier, and the ring gear at the rotation speed to obtain the desired speed ratio.

16. The method of claim 15, wherein the causing of the rotation of the remaining one of the sun gear, the planet carrier, and the ring gear includes causing rotation of the ring gear with the motor.

17. An electric generator device comprising: a rotor configured to receive a drive from a power source to rotate at a first rotational speed, a stator positioned opposite to the rotor, such that a relative rotation between rotor and stator generates an alternating electric current, the stator being rotatable; a transmission assembly configured to receive a torque from the power source, the transmission assembly coupled to the stator to cause a rotation of the stator at a second rotational speed; wherein the transmission assembly is adjusted based on the first rotational speed transmitted from the power source to the rotor to maintain a selected rotational speed ratio between first rotational speed and second rotational speed to generate the alternating electric current at a desired frequency.

18. The electric generator device of claim 17, wherein the transmission assembly includes interconnected rotating members including: an input member drivingly engaged by the input; and an output member drivingly engaging the output and drivingly engaged to the input member, the interconnecting rotating members configured for providing the speed ratio different than one between the input and the output of the transmission assembly.

19. The electric generator device of claim 18, wherein the interconnected rotating members include connecting members, the input member drivingly engaged to the output member via the connection members.

20. The electric generator device of claim 17, wherein the transmission assembly includes a planetary geartrain having: a sun gear; planet gears meshed with the sun gear; a planet carrier rollingly supporting the planet gears; and a ring gear meshed with the planet gears, wherein the power source is drivingly engaged to one of the sun gear, the planet carrier, and the ring gear, and the stator is drivingly engaged to another one of the sun gear, the planet carrier, and the ring gear.

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