Hybrid electric turbine engine control system

Abstract

A turbine engine is disclosed that includes a first electrical machine coupled to a low pressure shaft of the turbine engine and a second electrical machine coupled to a high pressure shaft of the turbine engine. The turbine engine includes one or more engine loads and an external electrical connection for transferring electrical power between the turbine engine and an electrical system of the aircraft. The turbine engine includes a power management system including a high voltage DC bus configured to transfer electrical power between the first and second electrical machines and an engine load and an external electrical connection. The power management system includes a control system configured to control power output from the first and second electrical machines and power input to the first and second electrical machines, and to control power delivered to the one or more engine loads and external electrical connections.

Description

Technical Field

[0001] The present invention relates to an electrical control system for a hybrid electric turbine engine. In particular, the present invention relates to an electrical network and control system for an aircraft turbine engine having at least two turbine shafts, each turbine shaft being connected to an electrical machine. Background Art

[0002] The aircraft needs to generate electrical power to maintain the engine electrical loads and the aircraft electrical loads. This power can be provided by a turbine. Turbofans are usually equipped with a generator (typically an integrated drive generator or a variable frequency generator) that typically draws power from the high-pressure shaft. Sometimes, the generator can act as a starter generator, such as a variable frequency starter generator. In a turboprop engine, an electrical machine connected to the low-pressure shaft or propeller shaft (rather than to the high-pressure shaft) can be used to draw power for the aircraft.

[0003] There is a need for an improved turbine engine. Summary of the invention

[0004] According to one aspect, the invention provides a turbine engine comprising any or all of the following features:

[0005] a first electrical machine coupled to a low pressure (LP) shaft of the turbine engine;

[0006] a second electrical machine coupled to a high pressure (HP) shaft of the turbine engine;

[0007] one or more engine loads;

[0008] an external electrical connection for transmitting electrical power between the turbine engine and an electrical system of the aircraft; and

[0009] A power management system, the power management system comprising:

[0010] a high voltage DC bus configured to transfer electrical power between the first and second electrical machines, the one or more engine loads, and the external electrical connection; and

[0011] A control system is configured to control power output from and input to the first and second electrical machines and to control power delivered to the one or more engine loads and the external electrical connection.

[0012] This arrangement provides an electrical power system architecture that is capable of powering all aircraft loads and engine loads, controlling the power draw between the HP shaft and the LP shaft within the turbine engine, and allowing power to be input on one of the two shafts of the turbine without the need for an external power source. By connecting multiple DC power supplies in parallel, the distribution of electrical power output on the LP shaft and the HP shaft of the turbine can be controlled, or even the direction of the power flow can be reversed to allow power transfer between the shafts. As the skilled person will appreciate, in the context of commercial aviation, high voltage refers to a voltage level between 540VDC and 1500VDC. This arrangement is particularly suitable for architectures as high-power DC electrical systems to cope with operating scenarios determined by hybrid propulsion systems, but this architecture is also suitable for any type of turbine equipped with at least two shafts (i.e., LP shaft and HP shaft). This solves the problem that current output solutions (typically via integrated drive generators or variable frequency generators) do not allow the above functions to be performed (i.e., splitting output on the shaft and transmitting power from one shaft to another). This provides the advantage of energy independence of the propulsion system. Furthermore, this arrangement does not rely on the use of a mechanical power transmitting or power splitting device, such as a differential or clutch mechanism.

[0013] The first electrical machine and the second electrical machine may each include a plurality of windings. The windings may be multi-phase windings. The windings may be connected to control electronics. The control electronics may include a rectifier and / or an inverter to convert between AC voltage and DC voltage. The control system may be configured to control operating parameters of the first electrical machine and the second electrical machine. The power management system may include electrical protection devices, such as circuit breakers.

[0014] The turbine engine may include a third electrical machine coupled to the LP shaft. The turbine engine may include a fourth electrical machine coupled to the HP shaft. The turbine engine may include a second busbar. The second busbar may be configured to transfer electrical power between the third electrical machine and the fourth electrical machine.

[0015] The high voltage DC bus may be electrically connected to the second bus. The turbine engine may include a second external electrical connector. The second external electrical connector may be configured to transfer electrical power between the turbine engine and an electrical system of the aircraft. The second bus may be configured to transfer electrical power between a third electrical machine and a fourth electrical machine, an engine load, and the second external electrical connector. The external electrical connector may be electrically connected to the second external electrical connector.

[0016] The control system may include an LP drive control unit. The LP drive control unit may be configured to regulate the current of the first electrical machine and / or provide monitoring and electrical protection to the first electrical machine. The control system may also include an HP drive control unit. The HP drive control unit may be configured to regulate the current of the second electrical machine and / or provide monitoring and electrical protection to the second electrical machine. The control system may further include a network and distribution control unit. The network and distribution control unit may be configured to regulate the network voltage. The network and distribution control unit may be configured to apply power output commands and power input commands received from an engine controller of the turbine engine. The network and distribution control unit may be arranged to configure a network and load supply management, and is configured to monitor electrical loads and currents in the network and / or protect the network from overload or overcurrent.

[0017] Alternatively, the control system may include an LP drive control unit and an HP drive control unit as defined above, and a voltage and power control unit. The voltage and power control unit may be configured to regulate the network voltage and may be configured to apply power output commands and power input commands received from an engine controller of the turbine engine.

[0018] Alternatively, the control system may comprise an LP drive control unit and an HP drive control unit as defined above, wherein the regulation of the network voltage and / or the application of power output commands and power input commands received from an engine controller of the turbine engine is provided by at least one of the LP drive control unit and the HP drive control unit.

[0019] The control system may include a network and distribution control unit. The network and distribution control unit may be arranged to configure the network and load supply management, and to monitor and protect the network. Advantageously, the above control system is particularly suitable for providing a power balancing operating mode and a power transfer operating mode as defined later.

[0020] The HP drive control unit can be configured to communicate directly with the engine controller. This communication can be carried out via the voltage and power control unit, or can alternatively be carried out via a connection that bypasses the voltage and power control unit. This embodiment is particularly advantageous for the engine starting operating mode.

[0021] The control system may include an engine starting operating mode. In the engine starting operating mode, the control system may be configured to supply power from the external electrical connection to at least one of the first electrical machine and the second electrical machine via the high voltage DC bus. The control system may be configured to interrupt power transmission between the first electrical machine and the high voltage DC bus when in the engine starting operating mode. In addition, the control system may be configured to supply power to the engine load when in the engine starting operating mode.

[0022] The control system may include a power balancing mode of operation.The control system may be configured to direct electrical power from the first and second electrical machines to the engine load and preferably to the external electrical connections via the high voltage DC bus when in the power balancing mode of operation.

[0023] The control system may include an engine restart operating mode. The control system may be configured to transfer power from the first electrical machine to the high voltage DC bus when in the engine restart operating mode. The control system may be configured to transfer power from the high voltage DC bus to the second electrical machine when in the engine restart operating mode. The control system may be configured to interrupt power transfer between the high voltage DC bus and the external electrical connection when in the engine restart operating mode. The control system may be configured to supply power to the engine load when in the engine restart operating mode.

[0024] The control system may include a power transfer operating mode. The control system may be configured to transfer power from a first electrical machine of the first electrical machine and the second electrical machine to a second electrical machine of the first electrical machine and the second electrical machine via the high voltage DC bus when in the power transfer operating mode. The control system may be configured to transfer power from the high voltage DC bus to an engine load and / or an external electrical connection when in the power transfer operating mode.

[0025] The control system may be configured to be switchable between two or more operating modes of the group having the above four operating modes.Preferably, the control system is configured to be switchable between three or four of the four operating modes defined above. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Further features and advantages of the invention will become apparent from the following description of embodiments of the invention presented by way of example only and with reference to the accompanying drawings, in which:

[0027] Figure 1 is a schematic diagram of an electrical network in a turbine engine according to an embodiment;

[0028] Figure 2 It is shown Figure 1 A schematic diagram of the operation mode of the network;

[0029] Figure 3 It is shown Figure 1 A schematic diagram of another operation mode of the network;

[0030] Figure 4 It is shown Figure 1 A schematic diagram of another operation mode of the network;

[0031] Figure 5 It is shown Figure 1 A schematic diagram of another operation mode of the network;

[0032] Figure 6 is a schematic diagram of an electrical network in a turbine engine according to another embodiment;

[0033] Figure 7 is a schematic diagram of a control system of an electrical network in a turbine engine according to an embodiment;

[0034] Figure 8 is a schematic diagram of a control system for an electrical network according to another embodiment;

[0035] Fig. 9 is a schematic diagram of a control system for an electrical network according to another embodiment;

[0036] Fig.10 is a schematic diagram illustrating a mode of operation of an electrical network according to an embodiment. DETAILED DESCRIPTION

[0037] The disclosure presented herein relates to a turbine engine for an aircraft. The turbine engine includes at least two shafts, such as a low pressure (LP) shaft and a high pressure (HP) shaft. Each of the LP shaft and the HP shaft is connected to an electrical machine. The electrical machine may be capable of acting as a motor and a generator, such as a permanent magnet generator (PMG). In this way, the LP shaft and the HP shaft may drive or be driven by a corresponding electrical machine. When acting as a generator, the electrical machine may generate a multi-phase (typically three-phase) AC voltage, which may be rectified by an AC / DC converter associated with the electrical machine. In this way, the electrical machine may provide a DC voltage. The DC voltage may be used to power engine loads (such as pumps and anti-icing systems) and aircraft loads (such as heaters and in-flight entertainment systems).

[0038] A system is provided to control power transmission between a shaft of a turbine engine and an aircraft load and an engine load. The system provides a direct current (DC) network, which may be a high voltage direct current (HVDC) network to connect power sources in parallel. A system for controlling the HVDC network controls power flow from or to each of these machines. In this case, "high voltage" refers to a voltage in the range of 540 VDC to 1500 VDC. The network includes a power management system including a bus connected to an electrical machine and an aircraft load and an engine load. The control system is configured to manage power routing between systems connected to the bus according to operating parameters required for various flight conditions.

[0039] Figure 1An electrical network of a turbine engine 100 in an aircraft 10 is shown. In the arrangement shown, the turbine engine 100 includes an LP shaft 101 connected to a first electrical machine 112. The first electrical machine 112 is configured to generate a three-phase AC voltage that can be converted into a DC voltage by a first converter 114 connected to the first electrical machine 112. The turbine engine 100 also includes an HP shaft 102 connected to a second electrical machine 122. The second electrical machine 122 is connected to a second converter 124 that is configured to convert the three-phase AC voltage into a DC voltage when the second electrical machine 122 acts as a generator.

[0040] The first electrical machine 112 and the first converter 114 may be included in the LP drive channel 110. The second electrical machine 122 and the second converter may be included in the HP drive channel 120. In the illustrated arrangement, the LP drive channel 110 and the HP drive channel 120 are electrically connected to a bus 132. The bus 132 is included in a power management system 130. The power management system 130 may be disposed in the engine 100. Specifically, the power management system 130 may be included within the perimeter of an integrated propulsion system of the aircraft 10. The bus 132 is connected to the engine load 103. The bus 132 is connected to the electrical network 12 of the aircraft 10 via an external electrical connector 150. The electrical network 12 of the aircraft 10 is connected to the aircraft load 14. Any or all of the electrical connectors mentioned herein may include protective devices, such as circuit breakers.

[0041] The power management system 130 includes a bus 132 that can be configured to transfer electrical power between the first electrical machine 112 and the second electrical machine 122 and one or more engine loads 103 and external electrical connections 150. In addition, the power management system 130 includes a control system 140. The control system 140 is configured to control the power output from the first electrical machine 112 and the second electrical machine 122 and the power input to the first electrical machine and the second electrical machine, and to control the power delivered to the one or more engine loads 103 and the external electrical connections 150. The power management system 130 is configured to control the distribution of electrical power output on the LP shaft and the HP shaft of the engine, and / or to reverse the direction of power flow to allow power transfer between the LP shaft and the HP shaft. This is achieved by connecting in parallel at least two DC power supplies generated by the LP drive channel 110 and the HP drive channel 120. This can be achieved by the control system 140 operating in several different operating modes and switching between them. Figures 2 to 5 In FIG. 1 , these operating modes are illustrated by a disconnect switch representing an interrupted electrical connection and a directional arrow representing the direction of power flow from one component to another.

[0042] Figure 2The engine start operation mode is shown. The control system 140 can adopt the engine start operation mode when starting the turbine engine. A power source external to the turbine engine (e.g., a power source provided in the aircraft 10 or via the aircraft, or a power source directly connected to the engine) can be used to supply power to the bus 132. The control system 140 can be configured to supply power to at least one of the first electrical machine 112 and the second electrical machine 122 from the external electrical connector 150 via the bus 132. In the illustrated arrangement, the control system 140 is configured to interrupt the power transmission between the first electrical machine 112 and the bus 132. In this way, only the HP drive channel 120 is supplied with power. In addition, in the illustrated arrangement, the control system 140 is configured to supply power to the engine load 103. Figure 2 The engine starting operating mode illustrated in is an operating mode using a power source external to turbine engine 100. In this mode, second electric machine 122 in HP drive channel 120 operates in a motoring mode, wherein the power supply provided by the external source is used to provide torque on the HP shaft.

[0043] Figure 3 A power balancing mode of operation of the control system 140 is shown. In the power balancing mode of operation, the control system 140 is configured to direct electrical power from the first electrical machine 112 and the second electrical machine 122 to the engine load 103 and the external electrical connection 150 via the bus 132. In this mode of operation, the first electrical machine 112 and the second electrical machine 122 both operate in a generator mode, wherein the rotation of the turbines produces a three-phase AC voltage that is converted by the first converter 114 and the second converter 124 into a DC voltage to be supplied to the electrical network via the bus 132. This mode of operation allows the control system 140 to control the power split between the LP drive channel 110 and the HP drive channel 120 to supply the engine load 103 and to supply the aircraft load 14 via the external electrical connection 150.

[0044] Figure 4The engine restart operation mode of the control system 140 is shown. In this operation mode, the control system 140 is configured to transmit power from the first electrical machine 112 to the bus 132 and transmit power from the bus 132 to the second electrical machine 122. In this operation mode, the control system can be configured to interrupt the power transmission between the bus 132 and the external electrical connection 150. In addition, the engine restart operation mode can allow the control system to supply power to the engine load 103. This operation mode can be applicable during the restart in flight, such as when the turbine is rotating. Although the drive speed is low, the first electrical machine 112 in the LP drive channel 110 can still generate electrical power. In addition to the engine load 103 (such as an electric fuel pump), this electrical power can be used to supply the second electrical machine 122 in the HP drive channel 120. In this mode, the first electrical machine 112 operates as a generator and the second electrical machine 122 operates as a motor, wherein, for example, the electrical power supplied to the HP drive channel 120 is used to drive the HP shaft to start the turbine. This has the advantage of extending the autonomous engine restart flight envelope.

[0045] Figure 5 A power transmission operating mode of the control system 140 is shown. In this operating mode, the control system 140 is configured to transmit power from one of the first electrical machine 112 and the second electrical machine 122 to the other of the first electrical machine 112 and the second electrical machine 122 via the bus 132. For example, in the illustrated arrangement, the control system 140 is configured to transmit power from the LP drive channel 110 to the HP drive channel 120 via the bus 132. In an alternative scenario, this operating mode can be configured to transmit power from the HP drive channel 120 to the LP drive channel 110 via the bus 132. In addition, the control system 140 can be configured to transmit power from the bus 132 to the engine load 103 and / or the external electrical connection 150. In this mode, one of the drive channels 110, 120 is switched to a motor mode to provide electrical assistance to its associated shaft. For example, in the illustrated arrangement, where the LP drive channel 110 supplies electrical power to the HP drive channel 120, the second electrical machine 122 operates in a motor mode to provide rotational drive to the HP shaft. At the same time, LP drive channel 110 continues to provide electrical power to other loads in the network, such as engine loads 103 and loads connected to external electrical connections 150, such as aircraft loads 14. To avoid overloading electrical machines operating in generator mode, control system 140 can be configured to temporarily stop supplying electrical power to non-critical engine functions or aircraft functions.

[0046] The control system 140 may be configured to switch between any of the above-described operating modes. For example, the control system 140 may be configured to switch between two or more of the above-described four operating modes. In this manner, the control system 140 may control power output from and power input to the electrical machines while providing power supply to the engine loads 103 and the aircraft loads 14 as required by flight conditions.

[0047] Figure 6 An alternative embodiment of a turbine engine 200 of an aircraft 20 having an electrical network is shown. The engine 200 includes an LP shaft 221 and an HP shaft 223. The engine 200 includes two LP drive channels 210, 215. The first LP drive channel 210 includes a first electrical machine 212 and a first converter 214, while the second LP drive channel 215 includes a third electrical machine 217 and a third converter 219. The first electrical machine 212 and the third electrical machine 217 associated with the LP drive channels 210, 215 can both be driven by the same LP shaft in the engine 200.

[0048] The engine further includes two HP drive channels 220, 225. The first HP drive channel 220 includes a second electric machine 222 and a second converter 224, while the second HP drive channel 225 includes a fourth electric machine 227 and a fourth converter 229. The two electric machines 222, 227 associated with the HP drive channels 220, 225 can be driven by the same HP shaft of the engine 200. The specifications of the electric machines 212, 217, 222, 227 and the converters 214, 219, 224, 229 can be combined with the above Figures 1 to 5 Specifications are similar to those described.

[0049] The engine 200 may include two power management systems 230, 235. In the illustrated arrangement, each power management system includes a bus 232, 237 and a control system 140a, 140b. The first power management system 230 includes a first bus 232 and a first control system 140a. The first bus 232 is connected to the first LP drive channel 210 and the first HP drive channel 220. The first bus 232 is also connected to the first engine load 201 and has a first external electrical connection 250, which is configured to be connected to the first electrical network 22 of the aircraft 20 to supply power to the first aircraft load 24. The first control system 140a is configured to control the power output from the first electrical machine 212 and the second electrical machine 222 and the power input to the first electrical machine and the second electrical machine, and to control the power delivered to the engine load 201 and the external electrical connection 250.

[0050] exist Figure 6, the second power management system 235 includes a second bus 237. The second bus 237 is connected to the second LP drive channel 215 and the second HP drive channel 225. The second bus 237 is also connected to the second engine load 202, and may include a second external electrical connection 255 to the electrical network 26 of the aircraft 20 to supply power to the second aircraft load 28. The second control system 140b is configured to control the power output from and input to the third electrical machine 217 and the fourth electrical machine 227, and control the power delivered to the second engine load 202 and the second external electrical connection 255.

[0051] like Figure 6 As shown in the example of , the electrical connector between the first bus 232 and the first engine load 201, and the electrical connector between the second bus 237 and the second engine load 202 can be connected to each other through the bridge 205, respectively. In this way, the control systems 140a, 140b can be configured to allow the first bus 232 to supply power to the second engine load 202, and / or allow the second bus 237 to supply power to the first engine load 201. This provides the possibility of powering both engine loads 201, 202 even if one of the drive channels fails. In this regard, each power management system 230, 235 may include its own control system 140a, 140b, such as Figure 6 The control system 140a, 140b can be a combination of the following Figures 7 to 10 Alternatively, the power management systems 230, 235 may be controlled by a single control system.

[0052] The first external electrical connector 250 and the second external electrical connector 255 may be connected by the second bridge 206. In this manner, the first bus 232 may be connected to the second aircraft load 28 via the second bridge 206, and the second bus 237 may be connected to the first aircraft load 24 via the second bridge 206. In this manner, the first control system 140a and the second control system 140b may be configured to supply power from the first bus 232 to the second aircraft load 28, and may also be configured to supply power from the second bus 237 to the first aircraft load 24. Any of the above connections may include protection devices (such as circuit breakers), which may be controlled by the first control system 140a and the second control system 140b.

[0053] Figure 7An embodiment of a control system 140 for a power management system for a turbine engine is shown. The control system 140 includes a network and distribution control unit 143. The network and distribution control unit 143 is connected to the engine electronic controller (EEC) of the full authority digital engine controller (FADEC). In the illustrated arrangement, the control system 140 includes an LP drive control unit 141 and an HP drive control unit 142. The LP drive control unit 141 and the HP drive control unit 142 can be configured to regulate current and provide various monitoring and protection. However, it should be understood that the control units 141, 142 can alternatively be part of the electrical machine of the LP drive channel and the HP drive channel, respectively, or can alternatively be located somewhere between the electrical machine and the network and distribution control unit 143 and the control system 140. In the illustrated arrangement, the LP drive control unit 141 and the HP drive control unit 142 are connected to a module 144 of the network and distribution control unit 143, which is configured to regulate the network voltage and apply the power output command and the power input command from the FADEC 15. In this way, the module 144 can regulate and pass instructions to the LP drive control unit 141 and the HP drive control unit 142. Furthermore, the network and distribution control unit 143 may comprise a module 145 arranged to configure the network load power supply management and to monitor and protect the network.

[0054] Figure 8 Another embodiment of a control system 240 is shown. The control system 240 includes a voltage and power control unit 246 and a network and distribution control unit 243. The control system may further include an LP drive control unit 241 and an HP drive control unit 242. The LP drive control unit 241 and the HP drive control unit 242 may be configured to regulate current and provide various monitoring and protection. The voltage and power control unit 246 includes a module 244 configured to regulate network voltage and apply power output commands and power input commands from the FADEC 15. The module 244 may be connected to the LP drive control unit 241 and the HP drive control unit 242 to communicate therewith. The network and distribution control unit 243 may include a module 245 arranged to configure network and load power supply management and provide network monitoring and protection. The module 245 may be connected to the FADEC 15.

[0055] Fig. 9Another embodiment of a control system 340 is shown. The control system 340 includes a network and distribution control unit 343. The network and distribution control unit 343 may include a module 345 arranged to configure network and load power supply management and provide monitoring and protection. The module 345 is configured to communicate with the FADEC 15. The control system 340 may also include an LP drive control unit 341 and an HP drive control unit 342, each of which is configured to regulate machine current and provide various monitoring and protection. Instead of a control system that includes separate modules for regulating network voltage and applying power output commands and power input commands from the FADEC 15, the control system 340 is configured so that these functions are provided by a voltage and power control unit 344 included in at least one of the LP drive control unit 341 and the HP drive control unit 342.

[0056] Fig.10 A control system 440 is shown. The control system 440 comprises a network and distribution control unit 443. The network and distribution control unit 443 comprises a module 445 arranged to configure the network and load power supply management and to monitor and protect the network. The module 445 is configured to communicate with the FADEC 15. Fig.10 An embodiment of the control system 440 is shown when in an engine starting mode of operation. As such, the FADEC 15 may be directly connected to the HP drive control unit 442 .

[0057] The control system 140, 240, 340, 440 may communicate with the FADEC 15 to: provide output capacity limitations (e.g., maximum output from each of the LP and HP shafts); provide proportional power output split commands; provide a preferred source of power output (i.e., LP or HP shaft); and / or provide any command for combined LP and HP outputs based on a control law and feedback to the total power output (i.e., a feedback loop).

[0058] Various modifications may be made to all of the above-described embodiments, whether by way of addition, deletion, and / or substitution, to provide further embodiments, any and / or all of which are intended to be encompassed by the appended claims.

Claims

1. A turbine engine, comprising: a first electrical machine coupled to a low pressure (LP) shaft of the turbine engine; a second electrical machine coupled to a high pressure (HP) shaft of the turbine engine; one or more engine loads; an external electrical connection for transmitting electrical power between the turbine engine and an electrical system of the aircraft; as well as A power management system, the power management system comprising: a high voltage DC bus configured to transfer electrical power between the first and second electrical machines, the one or more engine loads, and the external electrical connection; as well as A control system is configured to control power output from and input to the first and second electrical machines and to control power delivered to the one or more engine loads and the external electrical connection.

2. The turbine engine according to claim 1, wherein: The control system is configured to control operating parameters of the first electric machine and the second electric machine.

3. The turbine engine according to claim 1 or claim 2, wherein: The power management system includes an electrical protection device.

4. A turbine engine according to any preceding claim, wherein: The turbine engine further includes a third electric machine coupled to the LP shaft and a fourth electric machine coupled to the HP shaft.

5. The turbine engine according to claim 4, further comprising: A second busbar is configured to transfer electric power between the third electric machine and the fourth electric machine.

6. The turbine engine according to claim 5, wherein: The high voltage DC bus is electrically connected to the second bus.

7. The turbine engine according to any one of claims 4 to 6, further comprising: A second external electrical connection is provided for transmitting electrical power between the turbine engine and an electrical system of the aircraft.

8. The turbine engine according to claim 7, wherein: The second bus is configured to transfer electrical power between the third and fourth electric machines and the engine loads and the second external electrical connection.

9. A turbine engine according to claim 7 or claim 8, wherein: The external electrical connector is electrically connected to the second external electrical connector.

10. A turbine engine according to any preceding claim, wherein: The control system includes: an LP drive control unit configured to regulate current of the first electrical machine and / or provide monitoring and electrical protection to the first electrical machine; an HP drive control unit configured to regulate current to the second electrical machine and / or provide monitoring and electrical protection to the second electrical machine; and A network and distribution control unit is configured to regulate network voltage and apply power output commands and power input commands received from an engine controller of the turbine engine.

11. The turbine engine according to claim 10, wherein: The network and distribution control units are arranged to configure the network and load power supply management and to monitor electrical loads and currents in the networks and / or to protect the network from overload or overcurrent.

12. The turbine engine according to any one of claims 1 to 9, wherein: The control system includes: an LP drive control unit configured to regulate current of the first electrical machine and / or provide monitoring and electrical protection to the first electrical machine; an HP drive control unit configured to regulate current to the second electrical machine and / or provide monitoring and electrical protection to the second electrical machine; and A voltage and power control unit is configured to regulate the network voltage and apply power output commands and power input commands received from an engine controller of the turbine engine.

13. A turbine engine according to any one of claims 1 to 9, wherein: The control system includes: an LP drive control unit configured to regulate current to the first electrical machine and / or provide monitoring and electrical protection to the first electrical machine; and an HP drive control unit configured to regulate current to the second electrical machine and / or provide monitoring and electrical protection to the second electrical machine; Therein, regulation of the network voltage and / or application of power output commands and power input commands received from an engine controller of the turbine engine is provided by at least one drive control unit of the LP drive control unit and the HP drive control unit.

14. A turbine engine according to claim 12 or claim 13, wherein: The control system further comprises a network and distribution control unit arranged to configure the network and load power supply management, and to monitor and protect the network.

15. A turbine engine according to any one of claims 10 to 14, wherein: The HP drive control unit is configured to communicate directly with the engine controller.

16. A turbine engine according to any preceding claim, wherein: The control system includes an engine starting mode of operation in which the control system is configured to supply power from the external electrical connection to at least one of the first and second electrical machines via the high voltage DC bus.

17. The turbine engine according to claim 16, wherein: The control system is further configured to interrupt power transmission between the first electric machine and the high voltage DC bus when in the engine starting operating mode.

18. A turbine engine according to claim 17 or claim 18, wherein: The control system is further configured to supply power to the engine loads when in the engine starting mode of operation.

19. A turbine engine according to any preceding claim, wherein: The control system includes a power balancing mode of operation, and wherein the control system is configured to direct electrical power from the first and second electrical machines to the engine loads and the external electrical connection via the high voltage DC bus when in the power balancing mode of operation.

20. A turbine engine according to any preceding claim, wherein: The control system includes an engine restart operating mode, and wherein the control system is configured to transfer power from the first electric machine to the high voltage DC bus and transfer power from the high voltage DC bus to the second electric machine when in the engine restart operating mode.

21. The turbine engine according to claim 20, wherein: The control system is further configured to interrupt power transmission between the high voltage DC bus and the external electrical connection when in the engine restart operating mode.

22. A turbine engine according to claim 20 or claim 21, wherein: The control system is further configured to supply power to the engine loads when in the engine restart mode of operation.

23. A turbine engine according to any preceding claim, wherein: The control system includes a power transfer operating mode, and wherein the control system is configured to transfer power from a first electrical machine of the first electrical machine and the second electrical machine to a second electrical machine of the first electrical machine and the second electrical machine via the high voltage DC bus when in the power transfer operating mode.

24. The turbine engine according to claim 23, wherein: The control system is configured to transfer power from the high voltage DC bus to the engine loads and / or the external electrical connections when in the power transfer operating mode.

25. A turbine engine according to any preceding claim, wherein: The control system is configured to be able to switch between two or more operating modes in a set of operating modes defined by: An engine starting mode of operation as defined in any one of claims 16 to 18; The power balancing mode of operation as defined in claim 19; An engine restart mode of operation as defined in any one of claims 20 to 22; and A power transfer mode of operation as defined in claim 23 or claim 24.

26. The turbine engine according to claim 25, wherein: The control system is configured to be switchable between all four operating modes in the set of operating modes.

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