Drive arrangement for mechanically driven equipment

Abstract

To provide a train arrangement which is compact in size and is able to disconnect driven equipment from driving equipment during driving equipment start-up sequences in order to realize no-load start-up, and able to synchronize the driven equipment speed from stand-still to the driving equipment already at its nominal speed.SOLUTION: A hybrid gearbox for a mechanically driven equipment in a train system is connected between a power source and a load to be driven. The hybrid gearbox includes a layshaft gear capable of adjusting the transmission ratio between the power source and the load, and a motor-generator unit configured to adjust the transmission speed ratio arranged.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] A mechanically driven device or load, such as a pump or compressor, is driven by a suitable high power source, among which may be mentioned gas turbines, steam turbines, expanders, high power diesel and gas engines, or electric motors.

[0003] Generally, systems referred to as "trains", "train systems", etc. are available in 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, the transmission of power from the power source to the mechanical drive (or load) is via an input shaft to which the power source is connected, 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, the 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, if a fixed transmission ratio is used in the system, it is usually necessary that the driving equipment, i.e. the power source, is able to change the rotational speed of the transmission input shaft. In this case, the only possible driving equipment or power source can be, for example, a Variable Frequency Drive (VFD) 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 able to change the speed. However, these systems prove to be complex from a technical point of view, since it is necessary to equip the plant with large frequency converters for the electric motor or to increase the mechanical complexity of the power source.

[0006] In addition, 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, in which case the train system is not optimized in terms of CAPEX (footprint and weight) and OPEX (efficiency).

[0007] When using a variable ratio gearbox, a fixed speed electric motor or a single shaft gas turbine can be used as the power source. A train system with a variable ratio gearbox usually includes a planetary gearbox or derivative gearbox. This type of gearbox generally includes an annular wheel, a number of star wheels meshing with the annular wheel and held together by a star carrier, and a sun wheel that in turn meshes with the star wheel. The transmission ratio of a variable ratio planetary gearbox can be changed by changing the rotational speed of the star carrier relative to the annular wheel, or vice versa, by changing the rotational speed of the annular wheel relative to the star carrier, assuming that the transmission input shaft is connected to the annular wheel or the star carrier, respectively. The use of a variable ratio gearbox allows for greater design flexibility. As an alternative to planetary gears, a countershaft gearing can be used to realize a variable ratio gearbox, which includes an input sun wheel, a number of 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 providing gas turbines as driving equipment, in the case of a direct mechanical connection to the load via a fixed speed ratio transmission, during starting of the gas turbine, part of the torque is transferred to the transmission output shaft to which the load is connected. This entails that the gas turbine must withstand a load resistance during starting, which means that it is not possible to use a single-shaft gas turbine due to torque output limitations during starting. 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] Also, in train systems providing electric motors as drive equipment, in the case of a direct mechanical connection to the load, via a fixed speed ratio transmission, during the starting phase the electric motor experiences a load resistance given by its inertia. It is therefore necessary to use a motor with a higher power to cope with the power peaks required during the starting phase. This entails an increase in the train plant costs. Also, 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] The prior art includes US Pat. No. 6,715,291 (B1), which is directed to automotive applications for driving load terminals. The document discloses the control of a gearbox by a speed ratio generator unit arranged to be able to control the movement of the star wheel carrier in only one direction of rotation. Thus, the drive can only have one power input and two power outputs, whereas the present disclosure relates to drives that can have one power input and one power output, one power input and two power outputs, and two power inputs and one power output.

[0011] The prior art also includes US Patent Application Publication No. 2014 / 0378257(A1), which discloses a gear shaft control that has the main drawback of being cumbersome.

[0012] Based on the above, an improved variable speed ratio transmission that is compact in size and at the same time capable of decoupling the driven equipment from the driving equipment during the driving equipment start sequence to achieve no-load start, and then synchronizing the driven equipment speed to the driving equipment already at nominal speed from a stationary condition would be welcomed in the industry, allowing train equipment flexibility and at the same time being able to control the driven equipment speed to cover any operating condition. Summary of the Invention

[0013] In one aspect, the subject matter disclosed herein is directed to a countershaft gear arrangement, which may be a reducer or a speed increaser, having two sun wheel shafts, three or more compound star wheel shafts, and a star wheel carrier. 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 continuous controlled variable torque (CCVT). By varying the star carrier speed, the gear input / output speed ratio can be continuously changed.

[0014] An additional motor-generator unit (called a power balance motor-generator unit - MGU) may or may not be present to hold the gear output shaft and therefore enable the speed ratio motor-generator unit to start the power source such as a single shaft gas turbine, synchronous electric motor, diesel engine, and gas engine, or to keep the power source running to cover transient operating conditions such as idle, crank, online water wash, cool down, etc.

[0015] The above mentioned power balance motor generator unit allows power sources like single and dual shaft gas turbines or steam turbines or diesel and gas engines to keep operating at their maximum efficiency conditions and thus allows gas / power or steam / power or diesel / power balance based on energy availability and cost and thus covers gas turbine power surplus / deficit based on ambient conditions (winter / summer or night / day ambient temperature variations) and thus allows electrical energy storage in battery system to build spinning reserve.

[0016] The speed ratio motor generator unit includes the stator windings, stator core and permanent magnet rotor core radially mounted on the star carrier, while the power electronics includes low voltage active front end variable frequency drives and system control logic to capture or deliver energy to the grid or battery system. This is commercially relevant and enables energy conservation and storage in gas turbine based applications.

[0017] The power balance motor generator unit includes the stator windings, stator core, and permanent magnet rotor core radially mounted on the gear output shaft, while the power electronics includes a low voltage active front end variable frequency drive and system control logic to capture or deliver energy to the grid or battery system, which is commercially relevant and enables energy conservation and storage in gas turbine based applications.

[0018] In one aspect, the subject matter disclosed herein relates to a drive arrangement connected between a power source and a driven equipment 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 equipment. The hybrid gearbox also includes a speed ratio motor-generator unit configured to control the rotation of the star carrier, the motor-generator unit being disposed around the star carrier. In other words, the motor-generator unit is disposed annularly around the star carrier. It may be a brushless permanent magnet disposed annularly on the start carrier outer diameter and mounted directly on the start carrier outer diameter.

[0019] In another aspect, disclosed herein is a star carrier having a body with an outer diameter surface on which a rotor of a speed ratio motor-generator unit is mounted. The rotor can include a plurality of permanent magnets mounted on the outer diameter surface of the star carrier.

[0020] A further aspect of the disclosure relates to a method for operating a train system having a power source, a drive 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.

[0021] In another aspect, disclosed herein is a train system having a single-shaft gas turbine as a power source, and a speed ratio motor-generator unit rotates a star carrier to set a speed ratio such that the speed rotation of the output shaft is zero during the starting phase of the power source.

[0022] In another aspect, disclosed herein is a method for train systems having power sources such as single and dual shaft gas turbines or steam turbines or diesel or gas engines, where a portion of the power transmitted to the driven equipment is recovered and converted into electrical energy injected into the power grid or battery pack by a power balance motor generator unit, thus allowing the power source to operate at maximum efficiency and minimize CO2 production per equivalent total power output, and allowing the building of a spinning reserve.

[0023] In another aspect, disclosed herein are train systems having power sources such as single and dual shaft gas turbines, where the power balance motor generator unit is capable of compensating for gas turbine power surplus / deficiency based on ambient conditions (winter / summer or night / day ambient temperature variations), thus allowing for building or using spinning reserve.

[0024] In another aspect, disclosed herein is a train system having power sources such as diesel and gas engines, where the power balance motor generator unit is capable of compensating for diesel and gas engine power surplus / deficiency based on ambient conditions (winter / summer or night / day ambient temperature variations), thus allowing for building or using a spinning reserve. [Brief description of the drawings]

[0025] 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 arrangement according to a first embodiment; [Diagram 2] FIG. 1 illustrates a perspective view of a countershaft gearbox according to the present disclosure; [Diagram 3] FIG. 3 illustrates a longitudinal cross-sectional view of the countershaft gearbox of FIG. [Figure 4] 1 illustrates one embodiment of a schematic diagram of a control logic unit. [Diagram 5] 1 illustrates a flowchart of a method for operating a train system according to the present disclosure. [Figure 6] 1 illustrates a flow chart of a method for operating a train system including a single-shaft power turbine. [Figure 7] 1 illustrates a flow chart of a method for operating a train system including a dual-shaft power turbine. [Figure 8] 4 illustrates a further flow chart of a method for operating a train system including a dual-shaft power turbine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Mechanical drives require the connection of a power source, such as a gas turbine, electric motor, diesel engine, gas engine, etc., to a load. The connection is made by a transmission system, which can vary its transmission speed ratio to vary the driven equipment speed according to any possible operating condition. The transmission system includes a variable speed gearbox. The transmission speed ratio of the variable speed gearbox is adjusted by a motor-generator unit arranged around or annularly with the star carrier of the variable speed gearbox, which can operate either as a motor or as a generator to adjust the speed ratio of the gearbox.

[0027] Referring now to the drawings, FIG. 1 shows a train system T according to a first embodiment, generally designated by the reference numeral 1.

[0028] In particular, the train system T includes a power source 2, a drive device 1 connected to the power source 2 via an input shaft 3, and a load L, which in turn is connected to the drive device 1 via an output shaft 5. The drive device 1 also includes a hybrid gearbox 4 configured to transfer torque from the input shaft 3 to the output shaft 5.

[0029] 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 determines the torque C o and rotation speed ω o , is operatively connected to a hybrid gearbox 4 and a second motor-generator unit 6 for regulating the power transmitted to a 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.

[0030] The power source 2 can be of any type used in the field of mechanical drives. In particular, it can be a gas turbine of the two-shaft type, whose rotational speed can be varied, or a gas turbine of the single-shaft type, which operates 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 drives the input shaft 3 at a rotational speed ω i To rotate with C i A torque of 0.1 V can be delivered.

[0031] The hybrid gearbox 4 includes a countershaft gearbox 41 and a speed ratio motor-generator unit 42. The structure of the countershaft gearbox 41 will be described below, followed by disclosure of how the speed ratio motor-generator unit 42 is associated with the countershaft gearbox 41 and how it operates.

[0032] 2 and 3, it can be seen that the countershaft gearbox 41 comprises an input sunwheel 411 connected to the input shaft 3, and two or more (usually three) compound starwheel shafts 412, each compound starwheel shaft having a first gear stage 4121 meshing with the input sunwheel 411 and a second gear stage 4122. The countershaft gearbox 41 also comprises a star carrier 413 having a body 4131, on which an outer diameter surface 4132 is obtained, the function of which will be explained in a more understandable manner below.

[0033] The body 4131 of the star carrier 413 houses the input sun wheel 411 and the compound star wheel axle 412. Each compound star wheel axle 412 pivots about the body 4131 of the star carrier 413.

[0034] 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.

[0035] The speed ratio motor-generator unit 42 is a peripheral low voltage electric machine arranged on the entire outer diameter surface 4132 of the body 413 of the countershaft gearbox 41. In particular, the speed ratio motor-generator unit 42 is arranged annularly around the body 413 of the countershaft gearbox 41, covering the entire circumference. Referring again to Figure 3, the speed ratio motor-generator unit 42 includes a rotor 421 arranged on the outer diameter surface 4132 of the body 413 of the countershaft gearbox 41, and a stator 422 arranged around the rotor 421 and therefore around the outer diameter surface 4132 of the body 413 of the countershaft gearbox 41.

[0036] 3, rotor 421 includes or is comprised of a plurality of permanent magnets 4211 disposed on outer diameter surface 4132. In other embodiments, rotor 421 may be realized with windings.

[0037] 3, the stator 422 includes a stator core 4221 and a winding 4222. As can be seen from the vertical cross section of FIG.

[0038] The annular or peripheral arrangement of the ratio motor-generator units 42 on the outer diameter surface 4132 of the star carrier 413 allows a compact arrangement of the hybrid gearbox 4. In addition, taking into account the high powers involved to be transmitted, and the fact of the power sources 2 to which the drive 1 is intended to be connected, e.g. single-shaft gas turbines, two-shaft gas turbines, steam turbines, expanders, electric motors, diesel engines, etc., the described compact construction, and in particular the annular location of the ratio motor-generator units 42 over the entire circumference (annular) of the star carrier 413, allows an improved power transmission and reduces any risk of failure to operate the hybrid gearbox 4 and thus of blocking the drive 1.

[0039] 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 rotation 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

[0040] It should be noted that the star carrier 413 speed can be controlled in both rotation directions by the speed ratio motor-generator unit 42. This allows the drive assembly to be easily adapted and connected to any kind of power source 2, expanding the speed ratio adjustable range.

[0041] Since the speed ratio motor-generator unit 42 is arranged directly around the star carrier 413, i.e., as will be more clearly described above, annularly, and therefore over the entire circumference arranged annularly around the body 413, a high compactness of the assembly is obtained, as described above. Moreover, 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 speed ratio motor-generator unit 42. Moreover, since the countershaft gearbox 41, or more precisely the star carrier 413, is not blocked, it is possible not to transmit torque to the output shaft 5 when the speed ratio motor-generator unit 42 is switched off, so 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 a high degree of design freedom.

[0042] The speed ratio motor-generator unit 42 is, as mentioned above, a low voltage motor-generator unit that can operate both as an electric motor and as 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 1 delivers current to the grid N or the battery system and recovers part of the drive equipment output power according to a balance equation. Ci ω i =C c ω c +C o ω o 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.

[0043] 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 on the drive machine output power according to the following formula: C i ω i =C c ω c +C o ω o 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.

[0044] The drive device 1 includes a power balance motor-generator unit 6, which is an electric machine integrated in the output shaft 5 to adjust the torque demand of the output shaft 5, as mentioned above. The integration of the power balance motor-generator unit 6 in the output shaft 5 allows a compact construction and a more reliable system, since there is no presence of any transmission chain, such as a belt or gear, since the first one is arranged in an annular manner as well as the second one. The power balance motor-generator unit 6 can be of various types. In some embodiments, the power balance motor-generator unit 6 includes or consists of a number of permanent magnets 4211 installed on the outer diameter surface of the output shaft 5, or can be of the same speed ratio motor-generator unit 42 technology, thus also achieving in this case an overall reduced size, but also reducing the risk of any failure of the system.

[0045] As described above, the power balance motor-generator unit 6 is integrated with the output shaft 5. More specifically, with reference to Fig. 1, the power balance motor-generator unit (6) includes a rotor 61 mounted on the outer diameter surface of the output shaft 5, and a stator 62 disposed around the rotor 61. The stator 62 also includes a stator core 621 and a winding 622. As can be seen in the figure, the stator 62 surrounds the rotor 61.

[0046] In some embodiments, the rotor 61 also includes a plurality of permanent magnets 611 mounted on the outer diameter surface of the output shaft 5. In some other embodiments, the rotor 61 instead includes a plurality of windings disposed on the outer diameter surface of the output shaft 5.

[0047] In addition, the placement of the power balance motor-generator unit 6 all around the output shaft 5 has the effect of damping shaft vibrations that may be caused by disturbance harmonics or even any other undesirable vibrations across the output shaft 5.

[0048] And 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 an electric 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.

[0049] To explain the operation of the drive 1, the operation of the hybrid gearbox 4 of Figures 1, 2 and 3 is explained and the overall operation of the drive 1 is explained in different design configurations.

[0050] The operation of the hybrid gearbox 4 is as follows: With reference to FIG. 1 or FIG. 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 the 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 the arrow B. Thus, the output shaft 5 rotates in the direction indicated by the arrow C, which is the same direction as the arrow A. The rotation 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. on 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 the arrow D, i.e. according to the same direction of the arrow A of the input shaft 3, the rotation speed ω of the output shaft 5 becomes o If instead the star carrier 413 rotates in the opposite direction to the arrow D, i.e. according to the direction E, the rotation speed ω of the output shaft 5 increases. o More specifically, above a rotational speed threshold, the output shaft 5 can be brought to zero and no torque is transmitted to the load L.

[0051] Therefore, when the input shaft 3 rotates at a certain rotation speed ω i If the output shaft 5 is blocked while rotating at 40° C., the star carrier 413 will rotate in the direction according to the arrow E.

[0052] Operation of the 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, the 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.

[0053] 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.

[0054] Based on the above, in order to better disclose the advantages of the compact size of the hybrid gearbox 4 and the fact that the star carrier 413 speed can be controlled in both rotation directions, the operation of the drive assembly 1 is now described in different configurations in order to better understand its performance. More specifically, the configuration of the drive assembly 1 according to Fig. 1 can be adapted to any type of power source 2, whether or not it is capable of varying its 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.

[0055] The drive assembly 1 can operate both with a single shaft gas turbine as the power source 2, or any other fixed speed drive such as a synchronous or induction electric motor, where the rotational speed cannot be changed as is known, and with two-shaft gas turbines, steam turbines, expanders, VFD electric motors, diesel engines, and gas engines as the power source 2. The operation of the drive assembly 1 will be described for the cases where the power source 2 is a single shaft gas turbine and for the cases where the 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.

[0056] If the power source 2 is a single-shaft gas turbine, the drive assembly 1 starts the gas turbine from rest up to its crank speed, disconnects 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 increases the load L to bring the driven equipment up to its operating speed, and finally regulates the driven equipment speed within its operating speed range.

[0057] By means of the drive assembly 1, and referring again to FIG. 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.

[0058] 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 spinning mode") and the output shaft 5 is decoupled from the input shaft 3 (and then from the power source 2) so that the torque transmitted to the load L is substantially zero.

[0059] 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.

[0060] The torque is then gradually transferred by said control unit 7 to the load L, which allows the rotation of the output shaft 5 by the speed ratio motor-generator unit 42, which acts as a generator and slows down 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 stationary state (the power balance motor-generator unit 6 is switched off to keep the output shaft 5 rotating freely or acts 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 act as a generator, and then the star carrier 413 speed is increased in the opposite direction of rotation (direction according to the arrow D in FIG. 1) by the action of the speed ratio motor-generator unit 42, which now acts as a motor, which results in a further increase in the output shaft 5 speed.

[0061] The countershaft gearbox 41 is kinematically designed to bring the driven equipment to an operating point within its operative 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 operative speed range or act as a generator to serve the driven equipment at minimum operative speed (MOS) and adjust it in the direction according to arrow E up to the maximum speed of the star carrier 413, or act as a motor to serve the driven equipment at maximum continuous speed (MCS) and adjust it in the direction according to arrow D up to the maximum speed.

[0062] 5, a flow chart is shown summarizing a method 8 for operating a train system T having a generic power source 2. 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 piece of equipment L connected to an output shaft 5. The method 8 includes a step of adjusting the rotation of the star carrier 413 to set a transmission ratio of the countershaft gearbox 41 to adjust a speed ω o and torque C o The method further includes operating 84 the speed ratio motor-generator unit 42 to regulate

[0063] With reference to figure 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 comprises a sub-step 841 of operating the speed ratio motor-generator unit 42 as a motor to bring the gas turbine 2 to its crank speed, then a sub-step 842 of switching off the speed ratio motor-generator unit 42 so that the star carrier 413 rotates freely and disengaging the single-shaft gas turbine 2 to accelerate and 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 a standstill.

[0064] 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.

[0065] Finally, a step 85 of blocking the output shaft 5 during the start-up phase of the power source 2 by means of a power balance motor-generator unit 6 associated with the output shaft 5 may be included.

[0066] The drive assembly 1 disclosed herein can also be adapted for operation in the case of a two-shaft gas turbine as the 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, in fact, the corresponding pollution (in particular the CO2 emitted) is minimized proportionally per kilowatt (kW) generated. Thus, when operating a two-shaft gas turbine at maximum power and speed, the rotation speed ω of the input shaft 3 is ω i is fixed. The output shaft 5 rotation speed ω o can be adjusted by the star carrier 413 using the speed ratio motor-generator unit 42.

[0067] 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 energy generated in excess by the power source 2.

[0068] Furthermore, if the load L, for example, requires additional power at a different operating speed, the control unit 7 may adjust the rotation speed ω of the output shaft 5 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.

[0069] 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 the power) absorbed by the power balance motor-generator unit 6 .

[0070] With reference to FIG. 7, a flow chart is shown summarizing a method 8 for operating a train system T having a two-shaft gas turbine 2 as a power source. In addition to the above 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 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 ratio of the countershaft gearbox 41, the method 8 also includes a step 86 of recovering a part of the power transmitted to the output shaft 5, converting it into electrical energy and injecting it into the power grid or into the battery pack N of the power balance motor-generator unit 6 operable as a generator. In this way, as described above, the two-shaft gas turbine 2 can operate at maximum power and speed, i.e. with maximum efficiency, making it possible to minimize the CO2 generation per equivalent total power and to build a spinning reserve by recovering a part of the excess energy from the power source 2.

[0071] With reference to FIG. 8, a flow chart is also shown summarizing a method 8 for operating a train system T having a two-shaft gas turbine 2 as a power source. In addition to the above 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 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 balance 87 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 part of the power transmitted by the power source 2 to the output shaft 5, respectively, to cover the gas turbine power surplus / deficiency based on energy availability and cost or based on ambient conditions (winter / summer or night / day ambient temperature variations).

[0072] With reference to FIG. 9, a flow chart is shown summarizing a method 8 for operating a train system T having a two-shaft gas turbine 2 as a power source. In addition to the above 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 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 balance 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 part of the power transmitted by the power source 2 to the output shaft 5, respectively, thereby allowing the electric energy storage of the battery system to build a spinning reserve and cover the gas turbine power surplus / deficiency based on the ambient conditions (winter / summer or night / day ambient temperature variations).

[0073] If the drive source 2 is an electric motor, synchronous or induction electric motor, then at start-up it needs to provide peak power 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 requirement during the start-up phase, which results in increased component costs.

[0074] If the driving source 2 is a synchronous electric motor, its pulsating torque at start-up will intersect the train TNF (typically the first and second train torsional frequencies) and thus result in a heavy torque response at resonance, which may limit the start-up times due to fatigue phenomena.

[0075] The hybrid gearbox 4 allows starting the electric motor through the operation of the speed ratio motor-generator unit 42 and decoupling 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 eigenfrequency, which in fact generates dangerous torque responses in torque transmission devices such as couplings and shafts.

[0076] 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.

[0077] While aspects of the invention have been described in terms of various specific embodiments, it will be apparent to one of ordinary skill in the art that many modifications, changes, and omissions are possible without departing from the spirit and scope of the claims. In addition, unless otherwise specified herein, the order or sequence of any process or method steps may be changed or rearranged according to alternative embodiments.

[0078] Reference will now be made in detail to embodiments of the present disclosure, one or more examples of which are illustrated in the drawings. Each example is provided as an explanation of the present disclosure, not as a limitation of the present disclosure. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made to the present disclosure without departing from the scope or spirit of the present disclosure. References throughout this specification to "an embodiment" or "one embodiment" or "some embodiments" mean that a particular feature, structure, or characteristic described with respect to an embodiment is included in at least one embodiment of the disclosed subject matter. Thus, the appearance of the phrases "in an embodiment" or "in one embodiment" or "in some embodiments" in various places throughout this specification are not necessarily referring to the same embodiment. Moreover, particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0079] 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. A drive device (1) for driving a mechanical drive device (L), comprising: A power source (2) can be connected to the drive device (1), and the equipment (L) to be driven can be connected to the drive device (1), an input shaft (3) that can be connected to the power source (2); an output shaft (5) that can be connected to the device (L); A hybrid gearbox (4), a countershaft gearbox (41) comprising a star carrier (413) connected to the input shaft (3) and the output shaft (5) and configured to adjust a transmission speed ratio of the countershaft gearbox (41) between the input shaft (3) and the output shaft (5), the star carrier (413) comprising a body (4131) having an outer diameter surface (4132); a speed ratio motor-generator unit (42) configured to control the rotational speed of the star carrier (413), The speed ratio motor-generator units (42) are arranged in a peripheral annular manner on the outer diameter surface (4132) of the body (4132) of the star carrier (413), and the output shaft (5) comprises a power balance motor-generator unit (6) configured to control the output torque.

2. The speed ratio motor-generator unit (42) A rotor (421) installed on the outer diameter surface (4132) of the body (4132) of the star carrier (413); 2. The drive device (1) of claim 1, further comprising: a stator (422) arranged around the rotor (421), the stator (422) comprising a stator core (4221) and a winding (4222), the stator (422) surrounding the rotor (421).

3. 3. The drive device (1) according to claim 2, wherein the rotor (421) comprises a plurality of permanent magnets (4211) mounted on the outer diameter surface (4132) of the star carrier (413).

4. 3. The drive device (1) according to claim 2, wherein the rotor (421) comprises a plurality of windings arranged on the outer diameter surface (4132) of the star carrier (413).

5. A countershaft gearbox (41) an input sun wheel (411) connected to the input shaft (3); two or more compound star wheel shafts (412), each having a first gear stage (4121) meshing with the input sun wheel (411) and a second gear stage (4122); an output star wheel (414) connected to the output shaft (5) and meshing with the second gear stage 4122 of each compound star wheel shaft (412); the body (4131) of the star carrier (413) houses the input sun wheel (411), the compound star wheel axle (412), and the output star wheel (414); 2. The drive device (1) according to claim 1, wherein each compound star wheel axle (412) pivots around the housing (4131) of the star carrier (413).

6. a control unit (7) operatively connected to said speed ratio motor-generator unit (42) and configured to control the operation of said speed ratio motor-generator unit (42) to adjust the transmission speed ratio of said countershaft gearbox (41); The drive device (1) according to claim 1, wherein the control unit (7) is implemented as a low-voltage active front-end variable frequency drive including a computer and / or a cloud computing system and / or a computer network or other facility capable of processing data by executing a suitable computer program.

7. The control unit (7) 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) connected to the bus (72) so as to be accessed and controlled by the processor (71); 2. The drive device (1) of claim 1, further comprising: a receiver-transmitter module (75) connected to the bus (72) and configured to receive the signals from the speed ratio motor-generator unit (42) and from the power balance motor-generator unit (6) and to transmit control signals to the speed ratio motor-generator unit (42) and from the power balance motor-generator unit (6) to adjust operation of the drive assembly (1).

8. The control unit (7) is connected to a power grid (N) or a battery pack; 7. The drive device (1) according to claim 6, wherein the speed ratio motor-generator unit (42) is configured to operate as a generator or electric motor, to adjust the speed of the star carrier (413) and thus absorb at least a part of the power transmitted to the star carrier (413), to generate a current which is injected into the power grid (N) or a battery pack, or to absorb power from the power grid (N) or a battery pack and deliver power to the star carrier (413) of the countershaft gearbox (41).

9. a power balance motor-generator unit (6) operatively associated with said output shaft (5) and connected to said control unit (7); 7. The drive arrangement (1) of claim 6, wherein the power balance motor-generator unit (6) is configured to keep the power sources (2) operating at their maximum efficiency conditions, thus enabling power balancing based on energy availability and cost, and electrical energy storage in a battery system allows building up a spinning reserve.

10. The power balance motor-generator unit (6) A rotor (61) installed on the outer diameter surface output shaft (5); 10. The drive device (1) of claim 9, further comprising: a stator (62) arranged around the rotor (61), the stator (62) including a stator core (621) and a winding (622), the stator (62) surrounding the rotor (61).

11. The drive device (1) according to claim 10, wherein the rotor (61) comprises a plurality of permanent magnets (611) mounted on the outer diameter surface of the output shaft (5).

12. The drive device (1) according to claim 10, wherein the rotor (61) comprises a plurality of windings arranged on the outer diameter surface of the output shaft (5).

13. A train system (T), A drive device (1) according to any one of claims 1 to 9, a power source (2) connected to the input shaft (3) of the drive device (1); A train system (T) including: a load (L) connected to the output shaft (5) of the drive device (1).

14. 14. The train system (T) of claim 13, wherein the load (L) is a compressor, a pump, or a marine propeller.

15. The train system (T) according to claim 13, wherein the power source (2) is a single-shaft gas turbine, and / or a two-shaft gas turbine, and / or a steam turbine, and / or an expander, and / or an electric motor, and / or a diesel engine, and / or a gas engine.

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