Method for operating a train system for a mechanical drive device - Patent Application 20070122997

Abstract

A method of operating a train system for driving a mechanical drive device is disclosed, the train system including a hybrid gearbox connected between a power source and a load to be driven, the hybrid gearbox including a countershaft gear capable of adjusting a transmission speed ratio between the power source, the load, and a motor-generator unit configured to balance power generated by the power source and transmitted to the load.

Description

[Technical Field]

[0001] The present disclosure relates to a method for operating a drive unit for driving mechanical drive equipment in a train system. [Background technology]

[0002] A mechanical drive or load, such as a pump or compressor, is driven by a suitable power source, among which may be a gas turbine, a steam turbine, an expander, a diesel engine, a gas engine, or an electric motor.

[0003] Generally, systems referred to as "trains," "train systems," etc. are available on the market, in which a power source drives a load, such as one or more compressors, pumps, or marine propellers, via a transmission. More specifically, power is transmitted from the power source to the mechanical drive device (or load) via an input shaft connected to the power source, an output shaft connected to the load L, and a gearbox for changing the transmission ratio between the speed of the input shaft (i.e., power source) and the speed of the output shaft (i.e., load). Hereinafter, for ease of reference only, a system including the power source, the gearbox, and the load, e.g., a compressor, may be referred to as a "train," "train system," or "train plant."

[0004] The gearbox may be of different types, in particular of the fixed gear ratio type or of the variable gear ratio type.

[0005] Generally, it is necessary to change the speed of the driven equipment in some situations. Therefore, when a fixed transmission ratio is used in a system, it is usually necessary for the driving equipment, i.e., the power source, to be able to change the rotational speed of the transmission input shaft. In this case, the only possible driving equipment or power source may be, for example, a variable frequency drive (VFD), an electric motor, a two-shaft gas turbine, a steam turbine, an expander, a diesel engine, or a gas engine. In fact, these types of power sources are capable of changing speed. However, these systems prove to be complex from a technical point of view, since they require the plant to be equipped with a large frequency converter for the electric motor or increase the mechanical complexity of the power source.

[0006] Additionally, if the driving equipment is an electric motor with a VFD, the train system may experience sub-synchronous torsional interactions that may be transmitted through network disturbances to other train systems, such as generator drivetrains or mechanical drivetrains, resulting in the train system not being optimized in terms of CAPEX (footprint and weight) and OPEX (efficiency).

[0007] When using a variable gear ratio gearbox, a fixed-speed electric motor or a single-shaft gas turbine can be used as the power source. Train systems with variable gear ratio gearboxes typically include planetary or derivative gearboxes. This type of gearbox generally includes an annulus wheel, multiple star wheels meshing with the annulus wheel and held together by a star carrier, and a sun wheel that in turn meshes with the star wheel. The gear ratio of a variable gear ratio planetary gearbox can be changed by varying the rotational speed of the star carrier relative to the annulus wheel, or vice versa, by varying the rotational speed of the annulus wheel relative to the star carrier, assuming the transmission input shaft is connected to the annulus wheel or star carrier, respectively. The use of a variable gear ratio gearbox allows for greater design flexibility. As an alternative to planetary gears, a variable gear ratio gearbox can be realized using a countershaft gearing, which includes an input sun wheel, multiple star wheels meshing with the input sun wheel and held together by a star carrier, and an output sun wheel that in turn meshes with the star wheel.

[0008] In train systems using gas turbines as the driving equipment, in the case of a direct mechanical connection to the load via a fixed speed ratio transmission, part of the torque is transferred to the transmission output shaft to which the load is connected during start-up of the gas turbine. This entails that the gas turbine must withstand the load resistance during start-up, which means that it is not possible to use a single-shaft gas turbine due to torque output limitations during start-up. To prevent this type of problem, one or more clutches or large starting devices such as electric motors, steam turbines, or expanders are usually provided, which inevitably increase the cost and efficiency losses of the plant.

[0009] Furthermore, in train systems that use an electric motor as the drive source, a direct mechanical connection to the load via a fixed-ratio transmission means that during the starting phase, the electric motor experiences a load resistance due to its inertia. Therefore, a motor with a higher power output must be used to handle the power peaks required during the starting phase. This inevitably increases the train plant costs. In this case, the only alternative to a higher-power electric motor is the use of one or more clutches in the transmission chain.

[0010] Therefore, a need is felt for an improved variable speed ratio transmission that can decouple the driven equipment from the driving equipment during the driving equipment start sequence to achieve no-load starting, and then synchronize the driven equipment speed from a standstill to the driving equipment already at nominal speed to allow for train flexibility, while simultaneously controlling the driven equipment speed to cover any operating condition. Summary of the Invention

[0011] In one aspect, the subject matter disclosed herein is directed to a method for controlling the operation of a motor-generator unit and a countershaft gearing, which may be a reducer or a speed increaser, having two sun wheel shafts, three or more compound star wheel shafts, and a star carrier, to decouple the driven equipment from the driving equipment during a driving equipment start sequence, achieve a no-load start, and then synchronize the driven equipment speed from a standstill while the driving equipment speed is operating at its nominal speed. The star carrier speed is controlled by a motor-generator unit (also referred to as a speed ratio motor-generator unit—MGU) that functions as a Continuously Controlled Variable Torque (CCVT) system. By varying the star carrier speed, the gear input / output speed ratio can be continuously varied.

[0012] There may or may not be an additional motor-generator unit (called a power balance motor-generator unit - MGU) to hold the gear output shaft and thus enable the speed ratio motor-generator unit to start the power source such as a single-shaft gas turbine, synchronous electric motor, diesel engine, gas engine, or to keep the power source running to cover transient operating conditions such as idle, crank, online water wash, cool down, etc.

[0013] The above described method for controlling power balance motor-generator units allows power sources such as single-shaft and two-shaft gas turbines or steam turbines or diesel engines or gas engines to continue operating at their maximum efficiency conditions, thus enabling gas / electricity or steam / electricity or diesel / electricity balance based on energy availability and cost, thus covering gas turbine power surplus / deficit based on ambient conditions (winter / summer or night / day ambient temperature variations), and thus enabling electrical energy storage in battery systems to build a spinning reserve.

[0014] In one aspect, the subject matter disclosed herein relates to a drive arrangement connected between a power source and a driven device or load. The drive arrangement includes a hybrid gearbox having a countershaft gearbox including a star carrier configured to adjust the transmission speed ratio between the power source and the driven device. The hybrid gearbox also includes a speed ratio motor-generator unit. An operating method allows for controlling the rotation of the star carrier.

[0015] A further aspect of the present disclosure relates to a method for operating a train system having a power source, a drive device, and a load (driven equipment), the method including operating a speed ratio motor-generator unit to adjust the rotational speed of a star carrier, and setting a transmission speed ratio of a countershaft gearbox to adjust the speed and torque at an output shaft of the drive device.

[0016] In another aspect, disclosed herein is a train system having a single-shaft gas turbine as a power source, wherein the speed ratio motor-generator unit rotates the star carrier to set the transmission ratio such that the speed rotation of the output shaft is zero during a starting phase of the power source, or when the speed ratio motor-generator unit is switched off, the star carrier rotates in a free rotation mode to set the transmission ratio such that the speed rotation of the output shaft is zero during a starting phase of the power source.

[0017] In another aspect, disclosed herein is a method for operating a train system having a power source such as a single-shaft and two-shaft gas turbine or steam turbine or diesel engine or gas engine, wherein a portion of the power transmitted to the driven equipment is recovered and converted by a power balance motor-generator unit into electrical energy that is injected into the power grid or a battery pack, thus allowing the power source to operate at maximum efficiency and minimize CO2 production per equivalent total power output, and allowing for the building of a spinning reserve.

[0018] In another aspect, disclosed herein is a method of operating a train system having power sources such as single-shaft and dual-shaft gas turbines, wherein a power balance motor-generator unit is operated to compensate for gas turbine power surplus / deficit based on ambient conditions (winter / summer or night / day ambient temperature variations), thus allowing for building or utilizing spinning reserve. [Brief explanation of the drawings]

[0019] A more complete understanding of the disclosed embodiments of the present invention and many of the attendant advantages thereof will be readily obtained by reference to the following detailed description when considered in connection with the accompanying drawings, in which: [Figure 1] 1 illustrates a schematic diagram of a drive device according to a first embodiment; [Figure 2] FIG. 1 illustrates a perspective view of a countershaft gearbox according to the present disclosure. [Figure 3] FIG. 3 shows a longitudinal cross-section of the countershaft gearbox of FIG. [Figure 4] 1 illustrates one embodiment of a schematic diagram of a control logic unit. [Figure 5] 1 illustrates a flowchart of a method for operating a train system according to the present disclosure. [Figure 6] 1 illustrates a flowchart of a method for operating a train system including a single-shaft power turbine. [Figure 7] 1 illustrates a flowchart of a method for operating a train system including a dual-shaft power turbine. [Figure 8] 1 illustrates a further flow chart of a method for operating a train system including a dual-shaft power turbine. DETAILED DESCRIPTION OF THE INVENTION

[0020] Mechanical drive equipment requires the connection of a power source, such as a gas turbine, electric motor, diesel engine, or gas engine, to a load. This connection is made via a transmission system, which can vary its transmission speed ratio to change the driven equipment speed according to any possible operating condition, such as the start-up phase. The transmission system includes a variable speed gearbox. The transmission speed ratio of the variable speed gearbox is adjusted by a motor-generator unit annularly integrated with the star carrier of the variable speed gearbox. The motor-generator unit can operate as either a motor or a generator to adjust the gearbox's speed ratio, thus allowing the power source to be decoupled from the load until it reaches what is called crank speed, preventing nonlinear power transmission during the start-up phase mentioned above.

[0021] Referring now to the drawings, FIG. 1 shows a train system T according to a first embodiment, generally designated by reference numeral 1, operated in a method of operation according to the present disclosure.

[0022] In particular, the train system T includes a power source 2, a drive unit 1 connected to the power source 2 via an input shaft 3, and a load L connected to the drive unit 1 via an output shaft 5. The drive unit 1 also includes a hybrid gearbox 4 configured to transfer torque from the input shaft 3 to the output shaft 5.

[0023] The drive 1 also includes a control unit 7, which is a computer, and a power balance motor-generator unit 6 associated with the output shaft 5. The control unit 7 controls the torque C o and rotation speed ω o , is operatively connected to the hybrid gearbox 4 and the second motor-generator unit 6 for regulating the power transmitted to the load L. Further, the control unit 7 may be connected to a power grid or a battery pack N, as will be explained in more detail below.

[0024] The power source 2 can be of any type used in the field of mechanical drives. In particular, it can be a two-shaft gas turbine with variable rotational speed, or a single-shaft gas turbine operating at a fixed speed. Alternatively, the power source 2 can also be an electric motor, a steam turbine, an expander, a diesel engine, or a gas engine. The power source 2 rotates the input shaft 3 at a rotational speed ω i To rotate with C i The torque given by

[0025] The hybrid gearbox 4 includes a countershaft gearbox 41 and a speed ratio motor-generator unit 42. The structure of an embodiment of the countershaft gearbox 41 is described below, followed by embodiments of how the speed ratio motor-generator unit 42 is associated with the countershaft gearbox 41 and how the countershaft gearbox 41 operates.

[0026] 2 and 3, it can be seen that the countershaft gearbox 41 includes an input sun wheel 411 connected to the input shaft 3, and two or more (usually three) compound star wheel shafts 412, each compound star wheel shaft having a first gear stage 4121 and a second gear stage 4122 meshing with the input sun wheel 411. The countershaft gearbox 41 also includes a star carrier 413 having a body 4131, on which an outer diameter surface 4132 is obtained, the function of which will be explained more clearly below.

[0027] The body 4131 of the star carrier 413 houses the input sun wheel 411 and the compound star wheel axles 412. Each compound star wheel axle 412 pivots about the body 4131 of the star carrier 413.

[0028] The countershaft gearbox 41 also includes an output sun wheel 414 connected to the output shaft 5 and meshing with the second gear stage 4122 of each compound star wheel shaft 412. The output sun wheel 414 is also housed within the body 4131 of the star carrier 413.

[0029] In the embodiment illustrated in Figure 3, the speed ratio motor-generator unit 42 is a peripheral low voltage electric machine disposed on the outer diameter surface 4132 of the body 413 of the countershaft gearbox 41. In particular, the speed ratio motor-generator unit 42 is disposed annularly around the body 413 of the countershaft gearbox 41. With continued reference to Figure 3, the speed ratio motor-generator unit 42 includes a rotor 421 disposed on the outer diameter surface 4132 of the body 413 of the countershaft gearbox 41, and a stator 422 disposed around the rotor 421 and therefore around the outer diameter surface 4132 of the body 413 of the countershaft gearbox 41.

[0030] 3, rotor 421 includes or consists of a plurality of permanent magnets 4211 disposed on outer diameter surface 4132. In other embodiments, rotor 421 may be realized by windings.

[0031] 3, the stator 422 includes a stator core 4221 and a winding 4222. As can be seen from the vertical cross section of FIG.

[0032] The embodiment of the speed ratio motor-generator unit 42 of Figure 3 is particularly compact. However, in alternative embodiments, the speed ratio motor-generator unit 42 may be arranged in a different position relative to the countershaft gearbox 41 and connected to the countershaft gearbox 41 by a suitable shaft.

[0033] In operation, the speed ratio motor-generator unit 42 rotates (or controls the rotation of) the star carrier 413 relative to the input sun wheel 411 and the output sun wheel 414, and therefore the rotational speed ω of the output shaft 5, which is connected to the output sun wheel 414 as described above. o and torque C o It is possible to adjust

[0034] 1. As the ratio motor-generator unit 42 is arranged directly around the star carrier 413, a high degree of compactness in the assembly is achieved. Furthermore, as can be seen from the figure, the countershaft gearbox 41 is not blocked, but its movement, i.e. its relative rotation with respect to the input shaft 3 or the output shaft 5, is controlled by the ratio motor-generator unit 42. Furthermore, as the countershaft gearbox 41, or more precisely the star carrier 413, is not blocked, it is possible to transmit no torque to the output shaft 5 when the ratio motor-generator unit 42 is switched off, with the result that the power source 2 is not exposed to any resisting torque of the load L. As will be seen below, this embodiment avoids the insertion of a clutch in the kinematic chain and allows for great design freedom.

[0035] The speed ratio motor-generator unit 42 is, as mentioned above, a low voltage motor-generator unit that can operate as both an electric motor and a generator to control the rotation of the star carrier 413. When the speed ratio motor-generator unit 42 is in generator mode, the drive device 1 is balanced C i ω i =C c ω c +C o ω o According to the above, current is supplied to a grid N or a battery system that recovers part of the drive equipment output power. In the formula, C c and ω c are the torque and rotational speed, respectively, and their product is the power delivered to the grid N or the battery pack.

[0036] When the speed ratio motor-generator unit 42 is in motor mode, the drive 1 absorbs current from the grid or battery system and superimposes that power onto the drive machine output power according to the following formula: C i ω i +C c ω c =C o ω o

[0037] The control unit 7 is connected to the speed ratio motor-generator unit 42 and controls and regulates its rotation. In particular, by regulating the rotation of the star carrier 413 by the speed ratio motor-generator unit 42, the torque and speed transmitted to the load L can be adjusted accordingly, as will be explained more clearly below.

[0038] The drive device 1 includes a power balance motor-generator unit 6, which is an electric motor associated with the output shaft 5 for adjusting the rotation of the output shaft 5, as described above. The power balance motor-generator unit 6 can be of various types. In an embodiment, the power balance motor-generator unit 6 includes or consists of a plurality of permanent magnets 4211 mounted on the outer diameter surface of the output shaft 5, or can be of the same speed ratio motor-generator unit 42 technology.

[0039] Also, the power balance motor-generator unit 6 is a low voltage motor-generator machine that can operate either as an electric motor, and thus affecting the movement of the output shaft 5, or as a generator, and thus absorbing (at least a portion of) the power on the input shaft 3 and thus generating current. The shift in operation of the power balance motor-generator unit 6 from electric motor or generator is controlled by a control unit 7, as more clearly defined below.

[0040] To explain the operation of the drive unit 1, the operation of the hybrid gearbox 4 of Figures 1, 2 and 3 will be explained and the overall operation of the drive unit 1 will be explained in different design configurations.

[0041] The operation of the hybrid gearbox 4 is as follows: Referring to Figure 1 or Figure 3, when the star carrier 413 is held stationary, the speed ratio motor-generator unit 42 rotates in one direction, such as the direction indicated by arrow A, and the first gear stage 4121 and the second gear stage 4122 of the compound star wheel shaft 412 rotate in the opposite direction, indicated by arrow B. Therefore, the output shaft 5 rotates in the direction indicated by arrow C, which is the same direction as arrow A. The rotational speed ω of the output shaft 5 o is the rotation speed ω of the input shaft 3 i and depends on the transmission ratio of the compound star wheel shaft 412, i.e., the radii of the first gear stage 4121, the second gear stage 4122, the input sun wheel 411, and the output star wheel 414. When the star carrier 413 rotates in the direction indicated by arrow D, i.e., according to the same direction as arrow A of the input shaft 3, the rotational speed ω of the output shaft 5 o If instead the star carrier 413 rotates in the opposite direction of the arrow D, i.e. according to the direction E, the rotation speed ω of the output shaft 5 increases. o More specifically, above the rotational speed threshold, the output shaft 5 can be brought to zero and no torque is transmitted to the load L.

[0042] Therefore, when the input shaft 3 rotates at a certain rotation speed ω iIf the output shaft 5 is blocked while rotating at 40°, the star carrier 413 will rotate in the direction according to the arrow E.

[0043] Operation of drive assembly 1 is coordinated by a control unit 7, which may be configured as an active front-end variable frequency drive. In some embodiments, control unit 7 may be realized or implemented as a cloud computing system, a computer network, or other installation capable of processing data by executing appropriate computer programs.

[0044] In some embodiments, and with particular reference to FIG. 4 , the control unit 7 may include a processor 71, a bus 72 to which the processor 71 is connected, a database 73 connected to the bus 72 so as to be accessed and controlled by the processor 71, a computer-readable memory 74 also connected to the bus 72 so as to be accessed and controlled by the processor 71, and a receiver-transmitter module 75 connected to the bus 72 and configured to receive signals from the speed ratio motor-generator unit 42 and the power balance motor-generator unit 6 regarding their operation and to transmit control signals to the speed ratio motor-generator unit 42 and from the power balance motor-generator unit 6 to adjust the operation of the drive assembly 1 according to different possible embodiments in which the drive assembly 1 may operate.

[0045] Based on the above, the operation of the drive assembly 1 will be described in different configurations in order to better understand the performance and to illustrate the method of operation of the drive assembly 1. More specifically, the configuration of the drive assembly 1 according to Fig. 1 and the method of operation disclosed more clearly below can be adapted to any type of power source 2, whether or not it is capable of varying speed. This result is achieved by a control unit 7 that is configured to adapt the behavior of the hybrid gearbox 4 to different situations.

[0046] The method of operating train system T, and in particular drive assembly 1, allows drive assembly 1 to operate both with a single-shaft gas turbine or any other fixed-speed drive, such as a synchronous or induction electric motor, as power source 2, which, as is known, cannot change its rotational speed, and with two-shaft gas turbines, steam turbines, expanders, VFD electric motors, diesel, and gas engines as power source 2. The method of operation of drive assembly 1 will be described for the cases where power source 2 is a single-shaft gas turbine and where power source 2 is a two-shaft gas turbine or any variable-speed drive, and the technical and design advantages will be described in either case.

[0047] If the power source 2 is a single-shaft gas turbine, the drive assembly 1 can start the gas turbine from rest up to its crank speed, disconnect the load L (thus disconnecting the load L from the power source) during the acceleration phase of the gas turbine 2 from its crank speed to the gas turbine nominal speed, then increase the load L to bring the driven equipment up to its operating speed, and finally regulate the driven equipment speed within its operating speed range.

[0048] By means of the drive assembly 1, and again with reference to Figure 1, during the start-up phase of the single-shaft gas turbine 2, the speed ratio motor-generator unit 42 initially acts as a motor to rotate the star carrier 413 in the direction according to arrow E, thus bringing the gas turbine 2 up to its crank speed as described above.

[0049] The speed ratio motor-generator unit 42 is then switched off so that the single-shaft gas turbine 2 can accelerate to reach its nominal speed without any resisting torque coming from the load L. At this stage, the star carrier 413 is left rotating freely (usually referred to as "free-spin mode") and the output shaft 5 is decoupled from the input shaft 3 (and in turn from the power source 2) so that the torque transmitted to the load L is substantially zero.

[0050] In some embodiments, the output drive shaft 5 may also be blocked by the power balance motor-generator unit 6, which is controlled by the control unit 7, as described above. In this way, it is ensured that during acceleration of the gas turbine 2, only the countershaft gearbox 41, and in particular the rotation of the star carrier 413, is able to compensate for the speed increase of the gas turbine 2 and the input shaft 3. In this configuration, the power balance motor-generator unit 6 allows overall control of the torque transfer due to the rotation of the star carrier 413.

[0051] Torque is then gradually transmitted by the control unit 7 to the load L, which enables the rotation of the output shaft 5 by the speed ratio motor-generator unit 42. The speed ratio motor-generator unit 42 functions as a generator and slows the star carrier 413 from its "free-spinning mode". With the power source 2 at its nominal operating speed, any reduction in the star carrier 413 speed from its "free-spinning mode" results in an increase in the output shaft 5 speed from a standstill (the power balance motor-generator unit 6 is switched off to keep the output shaft 5 spinning freely, or functions as a helper if required). The star carrier 413 speed is further reduced from its "free-spinning mode" to zero speed by the action of the speed ratio motor-generator unit 42, which continues to function as a generator, and then the star carrier 413 speed is increased in the opposite rotational direction (direction according to arrow D in FIG. 1 ) by the action of the speed ratio motor-generator unit 42, which now functions as a motor, which results in a further increase in the output shaft 5 speed.

[0052] The countershaft gearbox 41 is kinematically designed to bring the driven equipment to an operating point within its operating speed range when the star carrier 413 speed is zero, so that the speed ratio motor-generator unit 42 can adjust the driven equipment speed within its operating speed range, or function as a generator for the driven equipment at minimum operative speed (MOS) and can adjust it in the direction according to arrow E up to the maximum speed of the star carrier 413, or function as a motor for the driven equipment at maximum continuous speed (MCS) and can adjust it in the direction according to arrow D up to the maximum speed.

[0053] 5, a flowchart of a method 8 for operating a train system T having a general power source 2 is shown. In particular, the method 8 includes a step 81 of generating power by the power source 2 to rotate an input shaft 3, a step 82 of transmitting the power generated by the power source 2 by a drive device 1, and a step 83 of driving a machine L connected to an output shaft 5. The method 8 adjusts the rotation of the star carrier 413 to set the transmission ratio of the countershaft gearbox 41 to adjust the speed ω at the output shaft 5. o and torque C o The method further includes operating 84 the speed ratio motor-generator unit 42 to adjust

[0054] 6, the operating method 8 is shown when the power source is a single-shaft gas turbine 2. As already mentioned above, the operating step 84 includes sub-step 841 of operating the speed ratio motor-generator unit 42 as a motor to bring the gas turbine 2 up to its crank speed, and then sub-step 842 of switching off the speed ratio motor-generator unit 42 so that the star carrier 413 rotates freely, thereby decoupling and accelerating the single-shaft gas turbine 2 to reach its nominal speed. The speed ratio motor-generator unit 42 then operates as a generator, according to sub-step 843, to decelerate the star carrier 413 and increase the output shaft 5 speed from standstill.

[0055] The method 8 for operating the train system T also includes a sub-step 844 of operating the speed ratio motor-generator unit 42 as a motor to increase the speed of the star carrier 413 in the opposite direction to step 843, thereby further increasing the speed of the output shaft 5.

[0056] Finally, a step 85 of blocking the output shaft 5 during the start-up phase of the power source 2 by the power balance motor-generator unit 6 associated with the output shaft 5 may be included.

[0057] The drive assembly 1 disclosed herein can also be adapted to operate in the case of a two-shaft gas turbine as power source 2. In particular, in this case, the two-shaft gas turbine optimizes its efficiency when operating at maximum power and speed. In this case, the corresponding pollution (in particular CO2 emitted) is in fact minimized proportionally per kilowatt (kW) generated. Therefore, when operating a two-shaft gas turbine at maximum power and speed, the rotational speed ω of the input shaft 3 is i is fixed. The rotation speed of the output shaft 5 is ω o can be adjusted by the star carrier 413 using the speed ratio motor-generator unit 42.

[0058] When the power balance motor-generator unit 6 operates as a generator to absorb part of the torque transmitted to the output shaft 5, the power absorbed by the load L is adjusted by the control unit 7. Thus, part of the power generated by the power source 2 can be recovered and converted into electrical energy by the power balance motor-generator unit 6. The electrical energy generated by the power balance motor-generator unit 6 can then be injected into the power grid N or into a battery system for future use, thus balancing the power transmitted to the load L and at the same time recovering the excess energy generated by the power source 2.

[0059] Furthermore, for example, if the load L requires additional power at a different operating speed, the control unit 7 may adjust the speed output shaft 5 rotation speed ω by adjusting the rotation of the star carrier 413. o and / or reduce the torque (and therefore the power) absorbed by the power balance motor-generator unit 6.

[0060] Furthermore, if, for example, the load L requires different power at a constant operating speed, the control unit 7 can adjust the torque (and therefore power) absorbed by the power balance motor-generator unit 6, or if necessary, provide a net power to the output shaft 5, acting as a motor, to compensate for the overall power balance.

[0061] Referring to FIG. 7, a flowchart of a method 8 for operating a train system T having a two-shaft gas turbine 2 as a power source is shown. The method 8 can also be operated with a single-shaft gas turbine, and in addition to the steps illustrated in FIG. 5 , which include step 81 of generating power with the gas turbine 2, step 82 of transmitting the power generated by the power source 2 with the drive device 1, step 83 of driving the equipment L connected to the output shaft 5, and step 84 of operating the speed ratio motor-generator unit 42 to adjust the rotation of the star carrier 413 and set the transmission ratio of the countershaft gearbox 41, the method also includes step 86 of recovering a portion of the power transmitted to the output shaft 5, converting it into electrical energy, and injecting it into the power grid or battery pack N for the power balance motor-generator unit 6, which can operate as a generator. In this way, as described above, the two-shaft gas turbine 2 can operate at maximum power and speed, i.e., maximum efficiency, which allows for minimizing CO2 generation per equivalent total power output and allows for building a spinning reserve by recovering a portion of the excess energy from the power source 2. Similarly, the single-shaft gas turbine 2 can be operated at maximum power and its nominal speed, i.e., at maximum efficiency, allowing for minimizing CO2 production per equivalent total power output and allowing for building a spinning reserve by recovering some of the excess energy from the power source 2.

[0062] 8, a flowchart of a method 8 for operating a train system T having a twin-shaft or single-shaft gas turbine 2 as a power source is also shown. In addition to the above-mentioned steps illustrated in FIG. 7, of generating power 81 by the gas turbine 2, transmitting the power generated by the power source 2 by the drive device 1, driving the equipment L connected to the output shaft 5, and operating the speed ratio motor-generator unit 42 to adjust the rotation of the star carrier 413 and set the transmission speed ratio of the countershaft gearbox 41, 84, the method 8 also includes a gas / power balance 87 step by using a power balance motor-generator unit 6 connected to the power grid as a motor or generator to deliver power to the output shaft 5 or absorb a portion of the power transmitted by the power source 2 to the output shaft 5, respectively, to cover the gas turbine power surplus / deficit based on energy availability and cost or based on ambient conditions (winter / summer or night / day ambient temperature fluctuations).

[0063] 8, a flowchart is shown summarizing a method 8 for operating a train system T having a twin-shaft or single-shaft gas turbine 2 as a power source. In addition to the above-mentioned steps illustrated in FIG. 5 of generating power 81 by the gas turbine 2, transmitting the power generated by the power source 2 by the drive device 1 82, driving the equipment L connected to the output shaft 5 83, and operating the speed ratio motor-generator unit 42 to adjust the rotation of the star carrier 413 and set the transmission speed ratio of the countershaft gearbox 41 84, the method 8 also includes a step of gas / power balancing 87 by using a power balance motor-generator unit 6 connected to the battery system as a motor or generator to deliver power to the output shaft 5 or absorb a portion of the power transmitted by the power source 2 to the output shaft 5, thereby allowing the electrical energy storage of the battery system to build a spinning reserve and cover gas turbine power surplus / deficit based on ambient conditions (winter / summer or night / day ambient temperature fluctuations).

[0064] If the drive source 2 is an electric motor, synchronous or induction, it must provide peak power at start-up to overcome the inertia of the load L. This requires the electric motor to be oversized in terms of power simply to compensate for this power demand during the start-up phase, which increases component costs.

[0065] If the driving source 2 is a synchronous electric motor, its pulsating torque at start-up will intersect with the train TNF (typically the first and second train torsional frequencies), thus resulting in a heavy torque response at resonance, which may limit the number of starts due to fatigue phenomena.

[0066] The hybrid gearbox 4 starts the electric motor through the operation of the speed ratio motor-generator unit 42 and decouples the load L, thus avoiding oversizing the electric motor as the power source 2 and at the same time avoiding torsional interaction with the train torsional eigenvalues, which in fact would cause dangerous torque responses in torque transmission devices such as couplings and shafts.

[0067] The same method steps can be applied to start a reciprocating engine, i.e. a gas or diesel engine, avoiding the installation of a dedicated starting device.

[0068] While aspects of the present invention have been described in terms of various specific embodiments, it will be apparent to those skilled in the art that many modifications, changes, and omissions are possible without departing from the spirit and scope of the claims. Additionally, unless otherwise specified herein, the order or sequence of any process or method steps may be varied or rearranged according to alternative embodiments.

[0069] Reference will now be made in detail to the embodiments of the present disclosure, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the disclosure, not as a limitation of the disclosure. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope or spirit of the disclosure. References throughout this specification to "an embodiment" or "one embodiment" or "some embodiments" mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the disclosed subject matter. Thus, the appearances of the phrases "in one embodiment," "in one embodiment," or "in some embodiments" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0070] When presenting elements of various embodiments, the articles "a," "an," "the," and "said" are intended to mean that there are one or more of the elements. The terms "comprising," "including," and "having" are intended to be non-exclusive and mean that there may be additional elements other than the listed elements.

Claims

1. 1. A method for operating a train system, comprising: the train system includes a power source and a drive device; the drive device has an input shaft connected to the power source, an output shaft, and a hybrid gearbox; the hybrid gearbox comprising: a countershaft gearbox connected to the input shaft and the output shaft; a star carrier configured to adjust a transmission speed ratio of the countershaft gearbox between the input shaft and the output shaft; and a speed ratio motor-generator unit configured to control rotation of the star carrier; The method comprises: operating the speed ratio motor-generator unit to start the power source; switching off the speed ratio motor-generator unit to decouple the load from the power source to accelerate the power source and place the star carrier in a free-spin mode; transmitting power generated by the power source through the drive device to a load connected to the output shaft; Including, The method, wherein the step of transmitting the power generated by the power source through the drive device to a load connected to the output shaft includes, after the step of placing the star carrier in the free rotation mode, operating the speed ratio motor-generator unit as a generator to decelerate the star carrier from the free rotation mode and increase the speed of the output shaft from a stationary state.

2. The method of claim 1 , wherein the power source is a single-shaft gas turbine.

3. after the step of operating the speed ratio motor-generator unit as a generator to decelerate the star carrier from the free rotation mode and increase the speed of the output shaft from a stationary state, the step of operating the speed ratio motor-generator unit as a motor to rotate the star carrier to further increase the speed of the output shaft, 3. The method of claim 2, wherein the direction of rotation of the star carrier in the step of operating the speed ratio motor-generator unit as a motor to rotate the star carrier to further increase the speed of the output shaft is opposite to the direction of rotation of the star carrier in the step of operating the speed ratio motor-generator unit as a generator to decelerate the star carrier from the free rotation mode and increase the speed of the output shaft from a stationary state.

4. the train system includes a power balance motor-generator unit that functions as an electric motor that adjusts the rotation of the output shaft or as a generator that converts at least a portion of the power of the output shaft into electric power; 4. The method of claim 2 or 3, further comprising the step of blocking rotation of the output shaft by the power balance motor-generator unit during start-up of the single-shaft gas turbine.

5. The method of claim 1 , wherein the power source is an electric motor.

6. The method of claim 1 , wherein the power source is a reciprocating engine.

7. A computer program comprising instructions which, when executed by a computer, cause the computer to perform the steps of the method of any one of claims 1 to 6.

8. A computer-readable storage medium storing instructions that, when executed by a computer, cause the computer to perform the steps of the method of any one of claims 1 to 6.

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