A method for monitoring and controlling a hybrid power train system

Abstract

A method (100) for monitoring and controlling a hybrid power train system (3, 4), wherein the method comprises: obtaining (101) at least one of a torque value of the hybrid power train system (3, 4) and a rotational speed value of the shaft (36); obtaining (103) state data comprising one or more status information of said hybrid power train system (3, 4); determining (105), based on the state data, an event affecting the operation of the hybrid power train system (3, 4); generating (107) one or more control signals to control at least one of the gas turbine (31) and the electrical machine (32) of said hybrid power train system (3, 4) based on the event and the at least one of the torque value and the rotational speed value; and transmitting (109) said one or more control signals.

Description

A method for monitoring and controlling a hybrid power train systemDescriptionTECHNICAL FIELD

[0001] The present disclosure concerns a method implemented at a control logic unit for monitoring and controlling a hybrid power train system, capable of maintaining the hybrid power train system operational during transition between one mode of operation to another.

[0002] The subject matter disclosed herein also refers to a hybrid power train turbine system for driving a load, such as compressors for compressing gas in pipeline transportation, a pump or any other rotary machine, and provided with a control logic unit that handles the hybrid power train system transitions across the different operative modes.BACKGROUND ART

[0003] Currently there are available in the market hybrid power train systems where the electrical machine is coupled with a gas turbine to drive a load, such as a compressor or a pump.

[0004] In these systems, the electrical machine works as an “helper” to supplement mechanical power to the load and keep the overall mechanical power delivered to the load constant when power availability of the gas turbine decreases, and / or increase the total mechanical power required to drive the load.

[0005] Examples of hybrid power train systems are those used in Liquefied Natural Gas (LNG) applications, in which the natural gas is cooled using one or more refrigeration cycles in a cascade arrangement, until it becomes liquid. In this application, the refrigerant is processed by one or more compressors powered by the hybrid power train system that delivers the necessary power to operate the one or more compressors. The expanded, chilled refrigerant is then used to remove heat from the natural gas flowing in a heat exchanger.

[0006] It is well known that the management of a hybrid power train system iscomplex, especially in case of an unexpected event that affects the operation of the hybrid power train system and / or when hybrid power train system transitions across operative modes.

[0007] Typically, these events are handled by an operator which may not have all the technical skills needed to properly control the operation of the hybrid power train system to allow smooth and safe transition from one operative mode to another operative mode, such as a target operative mode.

[0008] Therefore, it may be beneficial to provide a method for monitoring and controlling the hybrid power train system that provides smooth and safe transition from one operative mode to another operative mode.Documents US 2021 / 388733, US 2019 / 264692, and US 2020 / 173300 are representative of the available art.SUMMARY

[0009] Certain aspects commensurate in scope with the originally claimed disclosure are summarized below. These aspects are not intended to limit the scope of the claimed disclosure, but rather these aspects are intended only to provide a brief summary of possible forms of the disclosure. Indeed, the full disclosure may encompass a variety of forms that may be similar to or different from the aspects set forth below.

[0010] In one aspect, the subject matter disclosed herein is directed to a computer- implemented method at a control logic unit for monitoring and controlling a hybrid power train system, wherein the hybrid power train system comprises a shaft; a gas turbine mechanically connected to the shaft; and an electrical machine mechanically connected to the shaft and capable of operating as a generator or as a motor; wherein at least one of said electrical machine and said gas turbine is connectable to a load; and wherein the method comprises: obtaining at least one of a torque value of the hybrid power train system and a rotational speed value of the shaft; obtaining state data comprising one or more status information of said hybrid power train system; determining, based on the state data, an event affecting the operation of the hybrid power train system; generating one or more control signals to control at least one of the gas turbine and the electrical machine of said hybrid power train system based onthe event and the at least one of the torque value and the rotational speed value, so as to maintain at least one of a torque of the hybrid power train system at the torque value and a rotation speed of the shaft at the rotation speed value; and transmitting said one or more control signals.

[0011] In another aspect, the subject matter disclosed herein is directed to a control logic unit comprising a processor, configured to perform the above method; and a receiving-transmitting module, coupled with the processor, and configured to receive and transmit the one or more control signals generated by the processor to control the operation of the gas turbine and / or the electrical machine of the hybrid power train system.

[0012] In a further aspect, the subject matter disclosed herein is directed to a hybrid power train system comprising: a shaft; a gas turbine mechanically connected to the shaft; an electrical machine mechanically connected to the shaft and capable of operating as a generator or as a motor; and a control logic unit as provided above, that is operatively connected to the gas turbine and to the electrical machine.

[0013] In a further aspect, the subject matter disclosed herein is directed to a computer program product and / or a non-transitory tangible computer readable storage medium comprising instructions which, when executed by a control logic unit, cause the control logic unit to carry out the method provided above.BRIEF DESCRIPTION OF THE DRAWINGS

[0014] A more complete appreciation of the disclosed embodiments of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:Figure 1 illustrates a schematic view of a first embodiment of a hybrid power train system comprising a shaft, a gas turbine mechanically connected to the shaft, and an electrical machine mechanically connected to the shaft and capable of operating as a generator or as a motor, according to the present disclosure.Figure 2 illustrates a schematic view of a second embodiment of a hybrid power train system comprising a shaft, a gas turbine mechanically connected to theshaft, and an electrical machine mechanically connected to the shaft and capable of operating as a generator or as a motor, according to the present disclosure.Figure 3 shows the four operation modes of the hybrid power train system, according to the present disclosure.Figure 4 shows a schematic view of a control logic unit for monitoring and controlling a hybrid power train system, according to the present disclosure.Figure 5 illustrates a flowchart of the method at a control logic unit shown in figure 4 for monitoring and controlling a hybrid power train system shown in figure 1 or 2, according to the present disclosure.It is intended that the accompanying drawings show non-limiting examples of the disclosed subject matter. Other embodiments are therefore possible.DETAILED DESCRIPTION OF EMBODIMENTS

[0015] Embodiments of the disclosed subject matter provide techniques for monitoring and controlling a hybrid power train system. Other embodiments are within the scope of the disclosed subject matter.

[0016] Turbomachinery equipment, such as gas turbines, electric motors / generators, and compressors / pumps may be coupled together in various configurations called, “trains” or “hybrid power train system”.

[0017] During operation, the hybrid power train system may encounter unexpected events that affect the operation of the hybrid power train system, or a module thereof. The unexpected event may be an event that cause a transition from a current operative mode to a different, target operative mode of the hybrid power train system, and / or an event that precedes a change of operative mode of the hybrid power train system, and / or an event that is indicative that a change of operative mode of the hybrid power train system will follow.

[0018] For example, unexpected events that may affect turbine operations may include, but are not limited to, the exhaust temperature of the gas turbine being above a maximum temperature threshold, occurrence of combustion problems, the vibrationlevel of the gas turbine being above a maximum threshold. Exemplary unexpected events that may affect the electric machine operations may include, but are not limited to, the temperature of the electric motor windings being above a maximum threshold and the vibration level of the electric motor being above a maximum threshold. Exemplary unexpected events that may affect the compressors / pumps operations may include, but are not limited to, an antisurge valve malfunctioning, the vibration level of the compressor / valve being above a maximum threshold

[0019] Reference is now made to figure 1 which illustrates schematically a hybrid power train system 3 comprising a shaft 36, a gas turbine 31 mechanically connected to the shaft 36, and an electrical machine 32 mechanically connected to the shaft 36 and capable of operating as a generator or as a motor. This combination between the gas turbine 31 and the electrical machine 32 allows for integration of renewable energy sources with conventional oil and gas processes by energizing the electrical machine 32 and leading the gas turbine 31 run at partial load with the consequence of improving flexibility of the overall system and reducing emissions.

[0020] The gas turbine 31 can be of different types, such as a heavy-duty gas turbine, or an aeroderivative gas turbine. For example, the gas turbine 31 can be designed to generate a power supply of 30MW. It is appreciated that since the gas turbine 31 can be of a different type, the gas turbine 31 can be capable of generating a different power.

[0021] On the other hand, the electrical machine 32 can be also of different type. For example, the electrical machine 32 can be a variable frequency drive electric motor (VFD), which is often used in the field in combination with gas turbines to allow for flexible operation of the system. The use of this type of electrical machine 32 is often motivated by the fact that it is particularly easy to control.

[0022] Although the VFD electric motor can be capable of generating an electric power of 1-3MW, it is appreciated that since the electrical machine 32 can be of different type, the motor can be capable of generating different power.

[0023] The hybrid power train system 3 is connectable to a load L through at least one of the electrical machine 32 and the gas turbine 31. This allows to drive the load L, such as a compressor for compressing gas in pipeline transportation, a pump, or any other type of rotary machine.

[0024] During operation, the hybrid power train system 3 can be connected to an energy source, such as by way of example, a grid energy storage, a solar panel power plant, a wind power plant, a hydrothermal power plant, and a thermal power plant, which supplies the necessary power to the hybrid power train system 3.

[0025] With continuing reference to figure 1, figure 2 illustrates a second embodiment of a hybrid power train system 4. The same reference numbers designate the same or corresponding parts, elements or components already illustrated in figure 1 and described above, and which will not be described again.

[0026] The embodiment shown in figure 2 differs from the embodiment of figure 1 in that the electrical machine 32 is connectable to both the load L and the gas turbine 31 through corresponding shafts 36. The configuration shown in figure 2 is capable of operating in turbo compressor mode.

[0027] As shown in figures 1 and 2, the shaft 36 of the hybrid power train system 3, 4 may comprise one or more disconnecting devices 33. The disconnecting devices 33 may comprise clutches, such as self-synchronizing clutch or other types of disconnecting devices, which may be equipped with lock-in and lock-out devices, which, when activated, have the function of locking the disconnecting device in an engaged or disengaged position.

[0028] The gas turbine 31 and / or the electrical machine 32 may be connectable to the load L through the one or more disconnecting devices 33. For example, a selfsynchronized clutch may be placed between gas turbine 31 and the load L, to run the load L in full electric mode (Zero Emission mode), when the clutch is in a disengaged position.

[0029] Alternatively, the gas turbine 31 and / or the electrical machine 32 may be connectable to the load L without the need of a disconnecting device 33, therefore this description should not be considered limited to a hybrid power train system 3, 4 provided with one or more disconnecting devices 33 as shown in figures 1 and 2.

[0030] Referring now to figure 3, there are shown the four operation modes of the hybrid power train system 3, 4. These modes include the turbo generation mode, the full hybrid mode, the full electric mode (“zero emission” mode), and the turbocompressor mode.

[0031] In turbo generation mode, the electrical machine 32 installed on the same shaft of the hybrid power train system 4 absorbs power from the gas turbine 31, whenever the gas turbine 31 delivered power is greater than the power required by the load L, thus converting the additional power into electrical power. Using the electrical machine 32 as a power generator allows to maintain the power output of the gas turbine31 constant, notwithstanding the actual power request from the load L. The turbo generation mode allows to maximize the efficiency of the gas turbine 31.

[0032] For example, in turbo generation mode, the gas turbine 31 may be able to generate 30MW power, part of which (for example 50% of the maximum power generated by the gas turbine 31, namely 15MW) is absorbed by the load L, and the residual 50% of the power generated is absorbed by the electrical machine 32, and injected in the power grid.

[0033] In full hybrid mode, the gas turbine 31 is supported by the electrical machine 32. The latter is energized by converting electric power into mechanical power available for the load L. This mode of operation allows to increase the power availability to the load L and share the power demand from the load L between the gas turbine 31 and the electrical machine 32, thus extending the operational life of the hybrid power train system 3, 4, reducing emission and saving cost otherwise required for using fuel as primary energy source.

[0034] For example, in full hybrid mode, the gas turbine 31 may be operated in the starter / generator mode, so that the gas turbine 31 supplies the load L with (maximum) 28MW and the electrical machine 32 with (maximum) 2MW. The electrical machine32 can be also connected to the power grid so as to inject power into the same.

[0035] In full electric mode (zero emission mode) the electrical machine 32 delivers the total amount of power required by the load L, allowing operation without producing emissions. In this operation mode, the self-synchronized clutch placed between gas turbine 31 and the load L is in a disengaged position to keep the gas turbine 31 stopped. This mode of operation avoids loss of service in case an emergency shutdown of the gas turbine 31 occurs or some maintenance activities (i.e. changing air filters, emergency / safety loop checks) are required.

[0036] For example, in full electric mode, the gas turbine 31 is shut down and the electrical machine 32 supplies the load L, with a (maximum) power of 30MW.

[0037] Finally, in turbo compressor mode, the gas turbine 32 delivers the total amount of power required by the load L, allowing operation without the need of the electrical machine 31. In this operative mode, the hybrid power train system 3, 4 is provided with disconnecting device 33 placed between electrical machine 32 and the load L that is in a disengaged position to keep the electrical machine 32 isolated from the load L. This mode of operation avoids loss of service in case an emergency shutdown of the electrical machine 32 or when some other maintenance activities are required.

[0038] Figure 4 illustrates a logic control unit 2 which can be configured to control the operation of the hybrid power train system 3, 4, and which handles the hybrid train across the different operative modes, guaranteeing a smooth and safe transition from one operative mode to another operative mode.

[0039] The control logic unit 2 can be part of a Hybrid Control Management System (HCMS) of the hybrid power train system 3, 4, which is appointed to handle the different operative modes and increase the Customer service continuity. In particular, the HCMS is designed to comply with specific requirements and to not violate the operability boundaries of the drivers and driven machines.

[0040] The control logic unit 2 is operatively connected to the gas turbine 31 and to the electrical machine 32, for example through a fuel controller module 311 of the gas turbine 31, and an electric motor / generator controller 321 of the electrical machine 32, respectively, as shown in figure 4.

[0041] The fuel controller module 311 of the gas turbine 31 may comprise a plurality of sensors and actuators for the monitoring and controlling the gas turbine 31, so as to control the gas turbine in response to a speed control signal for the gas turbine 31.

[0042] The electric motor / generator controller 321 of the electrical machine 32 controls the AC motor speed and torque by varying motor input frequency and voltage, such as the input frequency of an AC motor of the electrical machine 32 and / or an input voltage of the AC motor of the electrical machine 32. The electricmotor / generator controller 321 is capable of varying these values in response to an electrical machine torque reference value.

[0043] As shown in figure 4, the control logic unit 2 comprises a processor 21, and a receiving-transmitting module 25, coupled with the processor 21, and configured to receive and transmit one or more control signals generated by the processor 21 to control the operation of the gas turbine 31 and / or the electrical machine 32 of the hybrid power train system 3, 4. The one or more control signals provide shaft line speed control and / or torque control in a manner that maintains stability of the hybrid power train system 3, 4, decreasing the risk of any service disruption and improving overall fault tolerance of the system against unexpected events that affect the hybrid power train system 3, 4.

[0044] The receiving-transmitting module 25 can transmit control signals to the fuel controller module 311 of the gas turbine 31, and to the electric motor / generator controller 321 of the electrical machine 32, to control the operations of the hybrid power train system 3, 4, in the different operative modes available. More specifically, the fuel controller module 311 and the electric motor / generator controller 321 respectively control the actuators of the gas turbine 31, and the electrical machine 32, to handle the hybrid power train system 3, 4 across the different operative modes.

[0045] The control logic unit 2 may also comprise a bus 22, to which the processor 21 is connected to; a database 23, connected to the bus 22, for storage of state data of the hybrid power train system 3, 4. The database 23 can be accessed and controlled by the processor 21 in order to retrieve and / or store state data of the hybrid power train system 3, 4. The control logic unit 2 may also comprise a computer-readable memory 24, connected to the bus 22, to be accessed and controlled by the processor 21.

[0046] The control logic unit 2 is configured to execute one or more computer programs for monitoring and controlling a hybrid power train system 3, 4. The program may be stored in a computer-readable storage medium 24 or a dedicated memory, and comprise a set of instructions which, when executed by a control logic unit 2, cause the control logic unit 2 to carry out the method as will be described below.

[0047] In some embodiments the control logic unit 2 can be a physical hardware, possibly installed as part of the hybrid power train system 3, 4, or and hardwareremotely arranged therefrom. For example, the control logic unit 2 may be based or run in a cloud, in this way only the part of the control logic unit 2 that transmits the control signal is installed as part of the hybrid power train system 3, 4, while a data processing part can be remotely located with respect to the hybrid power train system 3, 4. For example, the processing part can be located in a terminal or a server that is communicatively coupled via a wired or wireless connection to the hybrid power train system 3, 4 or part of the control logic unit 2 that transmits the control signal.

[0048] Reference is made to figure 5 that illustrates a flowchart of the method 100 at a control logic unit 2 for monitoring and controlling a hybrid power train system 3, 4. The method allows to handle the hybrid power train system 3, 4 across the different operative modes, guaranteeing a smooth and safe transition from one operative mode to another operative mode. The method described herein, however, is exemplary only and not limiting. The method may be altered, e.g., by having stages added, removed, or rearranged.

[0049] The method 100 comprises an initial step 101 of obtaining at least one of a torque value of the hybrid power train system 3, 4 and a rotational speed value of the shaft 36. These values are associated with a state of the hybrid power train system 3, 4 prior to the occurrence of the event affecting the hybrid power train system 3, 4.

[0050] The initial step 101 of obtaining at least one of a torque value of the hybrid power train system 3, 4 and a rotational speed value of the shaft 36 may be performed continuously, for example at a frequency rate of lOHz-lOOHz, preferably at a frequency rate of 25Hz. The frequency rate may depend on the application, for example, in an industrial control system, the torque value and the rotational speed value may be obtained at a rate of 100 times per second in order to detect and respond to potential safety hazards. The benefits of real-time monitoring include the ability to detect and respond to events quickly, improve operational efficiency, and prevent downtime.

[0051] The step 101 of obtaining a torque value of the hybrid power train system 3, 4 may comprise estimating the torque value of the hybrid power train system 3, 4 based on a signal received before the occurrence of the event affecting the hybrid power train system 3, 4, such as an event affecting one or more of the gas turbine 31, the electricalmachine 32, the shaft 36, and the one or more disconnecting devices 33. For example, the control logic unit 2 may use a torque estimation signal, such as a Compressor Polytropic Head signal (as defined in table 3 below), delivered up to the occurrence of the event to infer the actual torque absorbed by the load L and in turn the torque delivered by the gas turbine 31.

[0052] The method 100 proceeds with a step 103 of obtaining state data comprising one or more status information of the hybrid power train system 3, 4. Such as status information related to one or more of the gas turbine 31, the electrical machine 32, the disconnecting device 33, and the shaft 36. It should be understood however that state data should not be limited to the specific data mentioned below, and in fact may relate to any state data associated with any component of the hybrid power train system 3, 4. State data may be communicated to the processor 21 or retrieved from the database 23 whereby it is stored.

[0053] For example, state data may comprise one or more status information concerning the status of gas turbine 31 as provided in Table 1 below:Table 1

[0054] In addition, or alternatively, state data may comprise one or more status information concerning the status of the electrical machine 32 as provided in Table 2belowTable 2

[0055] In addition, or alternatively, state data may comprise one or more status information concerning other status information related to the hybrid power train system 3, 4, such as the data provided in Table 3 belowTable 3

[0056] At step 105 the method 100 proceeds with determining, based on the state data, an event affecting the operation of the hybrid power train system 3, 4, such as an event affecting one or more of: the gas turbine 31, the electrical machine 32, the shaft 36,and the one or more disconnecting devices 33. It should be understood however that event may affect any module associated with the hybrid power train system 3, 4 and should not be limited to the specific modules listed above.

[0057] The event may comprise a change of operative mode of the hybrid power train system 3, 4, such as a change from a first operative mode to a second, different, target operative mode. Alternatively, the event may comprise an event that can lead to a change of operative mode of the hybrid power train system 3, 4, such as an event that may precede a change of operative mode of the hybrid power train system 3, 4 or an event that is indicative that a change of operative mode of the hybrid power train system 3, 4 will follow.

[0058] The step 105 of determining an event affecting the hybrid power train system 3, 4 may comprise determining the target operative mode of the hybrid power train system 3, 4. For example, the target operative mode may be an operative mode associated to the specific event and the step 105 of determining the target operative mode may be performed by comparing the determined event against a database comprising a list of events and corresponding target operative modes. For example, an event indicative that an emergency shutdown of the electrical machine 32 has occurred may be associated with a turbo compressor mode as target operative mode.

[0059] The step 105 of determining an event affecting the hybrid power train system 3, 4 may comprise comparing the one or more status information with one or more corresponding pre-set values or information. This may be done, for example, by comparing the one or more status information against an event database comprising a list of events. For example, if the status information is an electrical machine generic trip, this can be associated to an event indicative that an emergency shutdown of the electrical machine 32 has occurred.

[0060] At step 107 the method 100 generates one or more control signals to control at least one of the gas turbine 31 and the electrical machine 32 of the hybrid power train system 3, 4 based on the determined event and the at least one of the torque value and the rotational speed value obtained at step 101, so as to maintain at least one of a torque of the hybrid power train system 3, 4 at the torque value and a rotation speed of the shaft 36 at the rotation speed value. The one or more control signals may be based onthe target operative mode of the hybrid power train system 3, 4.

[0061] The one or more control signals may comprise at least one of an electrical machine torque reference value of the electrical machine 32 and a speed control signal for the gas turbine 31. The electrical machine torque reference value may comprise a maximum / minimum torque to be applied at the electrical machine 32 to fulfil the power demand from the load L. The speed control signal for the gas turbine 31 may comprise a maximum / minimum speed to be applied at the gas turbine 31 to fulfil the power demand from the load L.

[0062] The one or more control signals may comprise a request signal to drive transition of the hybrid power train 3 from a first operative mode to a second operative mode, such as, for example, a gas turbine normal shutdown request signal, a gas turbine emergency shutdown request signal to allow automatic transition to a recovery state, an electrical machine normal shutdown request signal, an electrical machine emergency shutdown request signal. In this way hybrid power train 3 can be automatically transition to the desired recovery state.

[0063] Finally, at step 109 the method 100 transmits the one or more control signals generated at step 107. The one or more control signals may be transmitted to a fuel controller module 311 of the gas turbine 31, and an electric motor / generator controller 321 of the electrical machine 32, respectively, in order to control the hybrid power train system 3, 4.

[0064] For example, during full hybrid mode, the gas turbine 31 is supported by the electrical machine 32 and is controlled by a speed regulator loop through a fuel controller module 311 to accomplish centrifugal compressor requirements of the gas turbine. On the other hand, the electrical machine 32 follows a torque demand, such as a generic positive torque demand if it works as helper.

[0065] During this operation, the control logic unit 2 obtains at least one of a torque value of the hybrid power train system 3, 4 and a rotational speed value of the shaft 36 and subsequently receives one or more status information concerning the hybrid power train system 3, 4.

[0066] For example, from the state data, the control logic unit 2 can determine that aGas Turbine Trip Event signal has been received indicating that an emergency shutdown of the gas turbine 31 event has occurred. At this point the hybrid power train system 3, 4 transitions in full electric mode, whereby the electrical machine 32 will try to keep the service active. The control logic unit 2 uses the torque estimation signal, such the Compressor Polytropic Head signal, delivered up to the occurrence of the event to infer the actual torque absorbed by the load L and in turn the torque delivered by the gas turbine 31.

[0067] The control logic unit 2 will use the actual torque absorbed by the load L to generate and transmit control signal including electrical machine torque reference value, which set the torque demand for the electrical machine 32, and allows to control the AC motor torque by varying motor input frequency and voltage. In this way, the control logic unit 2 handles the hybrid power train system 3, 4 transition across the different operative modes, guaranteeing a smooth and safe transition from one operative mode to another operative mode and without causing the entire system to fail.

[0068] An advantage of the technical solutions of the present embodiments is to provide a control logic unit and a method for monitoring and controlling a hybrid power train system which provide shaft line speed control and stability of the hybrid power train system, decreasing the risk of any service disruption and improving overall fault tolerance against unexpected events that affect the hybrid power train system.

[0069] Another advantage of the present technical solutions is that control logic unit and the method for monitoring and controlling a hybrid power train system allow to handle the hybrid power train system across the different operative modes, guaranteeing a smooth and safe transition from one operative mode to another operative mode.

[0070] Another advantage of the present technical solutions is that control logic unit and the method for monitoring and controlling a hybrid power train system integrates torque control of the electrical machine.

[0071] While aspects of the invention have been described in terms of various specific embodiments, it will be apparent to those of ordinary skill in the art that many modifications, changes, and omissions are possible without departing form the spiritand scope of the claims. In addition, unless specified otherwise herein, the order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments.

[0072] For example, the subject matter described herein can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structural means disclosed in this specification and structural equivalents thereof, or in combinations of them. The subject matter described herein can be implemented as one or more computer program products, such as one or more computer programs tangibly embodied in an information carrier (e.g., in a machine readable storage device), or embodied in a propagated signal, for execution by, or to control the operation of, data processing apparatus (e.g., a programmable processor, a computer, or multiple computers). A computer program (also known as a program, software, software application, or code) can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file. A program can be stored in a portion of a file that holds other programs or data, in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub programs, or portions of code). A computer program can be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network.

[0073] The processes and logic flows described in this specification, including the method steps of the subject matter described herein, can be performed by one or more programmable processors executing one or more computer programs to perform functions of the subject matter described herein by operating on input data and generating output. The processes and logic flows can also be performed by, and apparatus of the subject matter described herein can be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit).

[0074] Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or moreprocessor of any kind of digital computer. Generally, a processor will receive instructions and data from a read only memory or a random access memory or both. The essential elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto optical disks, or optical disks. Information carriers suitable for embodying computer program instructions and data include all forms of non volatile memory, including by way of example semiconductor memory devices, (e.g., EPROM, EEPROM, and flash memory devices); magnetic disks, (e.g., internal hard disks or removable disks); magneto optical disks; and optical disks (e.g., CD and DVD disks). The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

[0075] To provide for interaction with a user, the subject matter described herein can be implemented on a computer having a display device, e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor, for displaying information to the user and a keyboard and a pointing device, (e.g., a mouse or a trackball), by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well. For example, feedback provided to the user can be any form of sensory feedback, (e.g., visual feedback, auditory feedback, or tactile feedback), and input from the user can be received in any form, including acoustic, speech, or tactile input.

[0076] The techniques described herein can be implemented using one or more modules. As used herein, the term “module” refers to computing software, firmware, hardware, and / or various combinations thereof. At a minimum, however, modules are not to be interpreted as software that is not implemented on hardware, firmware, or recorded on a non-transitory processor readable recordable storage medium (i.e., modules are not software per se). Indeed “module” is to be interpreted to always include at least some physical, non-transitory hardware such as a part of a processor or computer. Two different modules can share the same physical hardware (e.g., two different modules can use the same processor and network interface). The modules described herein can be combined, integrated, separated, and / or duplicated to support various applications. Also, a function described herein as being performed at aparticular module can be performed at one or more other modules and / or by one or more other devices instead of or in addition to the function performed at the particular module. Further, the modules can be implemented across multiple devices and / or other components local or remote to one another. Additionally, the modules can be moved from one device and added to another device, and / or can be included in both devices.

[0077] The subj ect matter described herein can be implemented in a computing system that includes a back end component (e.g., a data server), a middleware component (e.g., an application server), or a front end component (e.g., a client computer having a graphical user interface or a web browser through which a user can interact with an implementation of the subject matter described herein), or any combination of such back end, middleware, and front end components. The components of the system can be interconnected by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include a local area network (“LAN”) and a wide area network (“WAN”), e.g., the Internet.

[0078] Reference has been made in detail to the embodiments of the disclosure, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the disclosure, not limitation of the disclosure. In fact, 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. Reference throughout the specification to "one embodiment" or "an embodiment" or “some embodiments” means that the particular feature, structure or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrase "in one embodiment" or "in an embodiment" or "in some embodiments" in various places throughout the specification is not necessarily referring to the same embodiment s). Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.

[0079] When elements of various embodiments are introduced, 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 inclusive and mean that there may be additional elements other than the listed elements.

Claims

CLAIMS1. A computer-implemented method (100) at a control logic unit (2) for monitoring and controlling a hybrid power train system (3, 4), wherein the hybrid power train system (3, 4) comprises a shaft (36); a gas turbine (31) mechanically connected to the shaft (36); and an electrical machine (32) mechanically connected to the shaft (36) and capable of operating as a generator or as a motor; wherein at least one of said electrical machine (32) and said gas turbine (31) is connectable to a load (L); and wherein the method comprises: obtaining (101) at least one of a torque value of the hybrid power train system (3, 4) and a rotational speed value of the shaft (36); obtaining (103) state data comprising one or more status information of said hybrid power train system (3, 4); determining (105), based on the state data, an event affecting the operation of the hybrid power train system (3, 4); generating (107) one or more control signals to control at least one of the gas turbine (31) and the electrical machine (32) of said hybrid power train system (3, 4) based on the event and the at least one of the torque value and the rotational speed value, so as to maintain at least one of a torque of the hybrid power train system (3, 4) at the torque value and a rotation speed of the shaft (36) at the rotation speed value, wherein the one or more control signals comprises a request signal to drive transition of the hybrid power train (3) from a first operative mode to a second different operative mode of the hybrid power train system (3, 4), said first operative mode and second operative mode being selected from a plurality of operative modes comprising a turbo generation mode, a full hybrid mode, a full electric mode, and a turbo compressor mode; and transmitting (109) said one or more control signals.

2. The method (100) of claim 1, wherein said event comprises a change of operative mode of said hybrid power train system (3, 4), or an event that precedes said change of operative mode, or an event that is indicative that said change of operative mode of the hybrid power train system (3, 4) will follow.

3. The method (100) of claim 1 or 2, wherein the one or more control signals comprises at least one of: an electrical machine torque reference value and a speed control signal for the gas turbine (31).

4. The method (100) according to any one of the preceding claims, wherein the torque value of the hybrid power train system (3, 4) and the rotational speed value of the shaft (36) are values associated with a state of said hybrid power train system (3, 4) prior to the occurrence of the event affecting said hybrid power train system (3, 4).

5. The method (100) according to any one of the preceding claims, wherein obtaining (101) a torque value of the hybrid power train system (3, 4) comprises estimating the torque value of the hybrid power train system (3, 4) based on a signal received before the occurrence of the event affecting said hybrid power train system (3, 4).

6. The method (100) according to any one of the preceding claims, wherein said one or more status information comprises at least one of: an indication that the gas turbine (31) is running, an indication that an emergency shutdown of the gas turbine(31) has occurred, an indication that the gas turbine (31) is able to rotate, an indication that the electrical machine (32) is running, an indication that the electrical machine(32) is able to rotate, an indication that the electrical machine (32) is connected to a grid and it is capable to absorb / deliver power, an indication that an emergency shutdown of the electrical machine (32) has occurred, a value of the electrical machine DC grid voltage, a value of the electrical machine grid frequency, a value of the electrical machine grid delivered power, a Compressor Polytropic Head signal, a shaft keyphasor information, and an indication of a status of at least one disconnecting device (33).

7. The method (100) according to any one of the preceding claims, wherein determining (105) based on the state data an event affecting the hybrid power train system (3, 4) comprises comparing said one or more status information with one or more corresponding pre-set values or information.

8. The method (100) according to any one of the preceding claims, wherein determining (105) based on the state data an event affecting the hybrid power train system (3, 4) comprises determining a target operative mode of the hybrid power trainsystem (3, 4), and wherein the one or more control signals are generated based on the determined target operative mode of the hybrid power train system (3, 4).

9. The method (100) according to any one of the preceding claims, wherein the shaft (36) of the hybrid power train system (3, 4) comprises one or more disconnecting devices (33), the at least one of the gas turbine (31) and the electrical machine (32) of said hybrid power train system being connectable to the load (L) through said one or more disconnecting devices (33).

10. A control logic unit (2) comprising: a processor (21), configured to perform the method of any one of the preceding claims; and a receiving-transmitting module (25), coupled with the processor (21), and configured to receive and transmit the one or more control signals generated by the processor (21) to control the operation of the gas turbine (31) and / or the electrical machine (32) of the hybrid power train system (3, 4).

11. The control logic unit (2) of claim 10, comprising: a bus (22), to which the processor (21) is connected to; a database (23) for storage of a state data of said hybrid power train system (3, 4), said database (23) being connected to the bus (22), so as to be accessed and controlled by the processor (21); and a computer-readable memory (24), connected to the bus (22), to be accessed and controlled by the processor (21).

12. A hybrid power train system (3, 4) comprising: a shaft (36); a gas turbine (31) mechanically connected to the shaft (36); an electrical machine (32) mechanically connected to the shaft (36) and capableof operating as a generator or as a motor; and a control logic unit (2) of claim 10 or 11, operatively connected to the gas turbine (31) and to the electrical machine (32).

13. A computer program product comprising instructions which, when the program is executed by a control logic unit (2) of claim 10 or 11, cause the control logic unit (2) to carry out the method of any one of claims 1-9.

14. A computer-readable storage medium (24) comprising instructions which, when executed by a control logic unit (2) of claim 10 or 11, cause the control logic unit (2) to carry out the method of any one of claims 1-9.

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