JP7542461B2 - Aircraft Propulsion Systems - Google Patents

Description

The present invention relates to an aircraft propulsion system.

Conventionally, there is known an aircraft propulsion system in which multiple engines are attached to the aircraft body and generators are connected to the engines (see, for example, Reference 1). This aircraft propulsion system has a main battery and a generator that supply power to an electric motor, and when the remaining charge of the main battery falls below a threshold, the main battery is charged with electricity converted from the power from the engine that drives the generator.

JP 2016-88110 A

However, conventional aircraft propulsion systems require the installation of a storage battery to supply power to be used in the event of an abnormality, in addition to the power supplied from the storage battery used during normal flight, which leads to an increase in the capacity of the storage battery, an increase in the amount of heat generated, and an increase in the cooling system to suppress heat generation. As a result, the above increases lead to an increase in the weight of the propulsion system and a decrease in the aircraft's payload.

The present invention was made in consideration of these circumstances, and one of its objectives is to provide an aircraft propulsion system that can reduce the capacity and weight of the onboard storage battery.

The aircraft propulsion system according to the present invention employs the following configuration.
(1): An aircraft propulsion system includes an engine mounted on a body of the aircraft, a generator connected to an engine shaft of the engine, a storage battery that charges the electric power generated by the generator, a charge amount detection unit that detects a state of charge of the storage battery, an electric motor driven by electric power supplied from the generator and the storage battery, a rotor driven by a driving force output by the electric motor, and a control unit that controls the electric power supplied from the storage battery to the electric motor by controlling a connection unit that connects the storage battery and the electric motor, and the control unit detects whether the state of charge of the storage battery at the time when the first state ends is within a first charging range when a flight state of the aircraft changes from a first state to a third state via a second state. the control unit controls the connection unit so that, while the flight state is in the first state, power is supplied exclusively from the storage battery to the electric motor; the control unit controls the connection unit so that, while the flight state is in the second state, power is supplied exclusively from the generator to the electric motor; the control unit controls the connection unit so that, while the flight state is in the second state, power generated by the generator is supplied to the storage battery so that the charge of the storage battery is within a second charging range at the time when the third state ends; the control unit controls the connection unit so that, while the flight state is in the third state, power is supplied exclusively from the storage battery to the electric motor; the second state is a state in which altitude change is smaller than in the first state and the third state.

(2): An aircraft propulsion system includes an engine mounted on the fuselage of the aircraft, a generator connected to an engine shaft of the engine, a storage battery that charges the electric power generated by the generator, a charge amount detection unit that detects the charge state of the storage battery, an electric motor driven by the electric power supplied by the generator and the storage battery, a rotor driven by a driving force output by the electric motor, and a control unit that controls a connection unit that connects the storage battery and the electric motor to control the electric power supplied from the storage battery to the electric motor, and the control unit sets the charge amount of the storage battery before the first state so that the charge state of the storage battery at the time the first state ends is within a first charging range when the flight state of the aircraft changes from a first state to a third state via a second state, and controls the connection unit so that electric power is supplied from the generator and the storage battery to the electric motor while the flight state is in the first state. The control unit controls the connection unit so that, while the flight state is in the second state, power is supplied exclusively from the generator to the electric motor; while the flight state is in the second state, the control unit controls the connection unit so that power generated by the generator is supplied to the storage battery so that the charge of the storage battery is within a second charging range when the third state ends; while the flight state is in the third state, the control unit controls the connection unit so that power is supplied from the generator and the storage battery to the electric motor; the second state is a state in which the altitude change is smaller than in the first state and the third state.

(3): In the above embodiment (1) or (2), the lower limit values of the first charging range and the second charging range are both zero.

(4): In the above aspects (1) to (3), before the aircraft takes off, the storage battery is charged to the set charge level by power supplied from an external ground power source or by power generated by the generator.

(5): The aircraft propulsion system includes an engine mounted on the aircraft body, a generator connected to the engine shaft of the engine, a storage battery that charges the power generated by the generator, a charge amount detection unit that detects the charge state of the storage battery, an electric motor driven by the power supplied by the generator and the storage battery, a rotor driven by the driving force output by the electric motor, and a control unit that controls a connection unit that connects the storage battery and the electric motor to control the power supplied from the storage battery to the electric motor, and the control unit controls the connection unit so that, when the generator is usable, power is supplied exclusively from the generator to the electric motor, and when the generator is unusable, controls the connection unit so that power is supplied only from the storage battery to the electric motor, and the charge amount of the storage battery is set so that the charge amount is equal to or greater than a third threshold when the aircraft lands.

According to aspects (1) to (4), the weight of the on-board storage battery can be reduced by charging the battery during cruising.
According to the aspect (5), the weight of the storage battery can be reduced by supplying power from the storage battery only when the generator breaks down.

1 is a diagram illustrating an aircraft propulsion system mounted on an aircraft. A diagram showing an example of the functional configuration of the aircraft 1. 1 is a diagram for explaining the flight state of an aircraft 1. FIG. 4 is a flowchart showing an example of a flow of processing executed by the control device 100. 4 is a flowchart showing an example of a flow of processing executed by the control device 100.

Below, an embodiment of an aircraft propulsion system of the present invention will be described with reference to the drawings.

<First embodiment>

[Overall configuration]

Figure 1 is a schematic diagram of an aircraft 1 equipped with an aircraft propulsion system. The aircraft 1 includes, for example, an airframe 10, multiple rotors 12A-12D, multiple electric motors 14A-14D, and arms 16A-16D. Hereinafter, when the multiple rotors 12A-12D are not distinguished from one another, they will be referred to as rotor 12, and when the multiple electric motors 14A-14D are not distinguished from one another, they will be referred to as electric motor 14. The aircraft 1 may be a manned aircraft or an unmanned aircraft. The aircraft 1 is not limited to the illustrated multicopter, but may also be a helicopter or a compound type aircraft equipped with both rotors and fixed wings.

The rotor 12A is attached to the airframe 10 via the arm 16A. The electric motor 14A is attached to the base (rotation shaft) of the rotor 12A. The electric motor 14A drives the rotor 12A. The electric motor 14A is, for example, a brushless DC motor. The rotor 12A is a fixed wing with blades that rotate around an axis parallel to the direction of gravity when the aircraft 1 is in a horizontal position. The rotors 12B to 12D, the arms 16B to 16D, and the electric motors 14B to 14D have the same functional configuration as above, so their explanations are omitted.

By rotating the rotor 12 in response to the control signal, the aircraft 1 flies in the desired flight state. The control signal is a signal for controlling the aircraft 1 based on the operation of an operator or instructions in automatic piloting. For example, the aircraft 1 flies by rotating rotors 12A and 12D in a first direction (e.g., clockwise) and rotors 12B and 12C in a second direction (e.g., counterclockwise). In addition to the rotor 12 described above, auxiliary rotors for maintaining attitude or for horizontal propulsion (not shown) may also be provided.

Figure 2 is a diagram showing an example of the functional configuration of the aircraft 1. In addition to the configuration shown in Figure 1, the aircraft 1 includes, for example, first control circuits 20A, 20B, 20C, and 20D, a storage battery unit 30, a second control circuit 40, a generator 50, and a gas turbine engine (hereinafter referred to as "GT") 60. Hereinafter, when the first control circuits 20A to 20D are not to be distinguished from one another, they will be referred to as the first control circuit 20.

The first control circuit 20 is a PDU (Power Drive Unit) that includes a drive circuit such as an inverter. The first control circuit 20 converts the power supplied by the storage battery unit 30 by switching or the like, and supplies the converted power to the electric motor 14. The electric motor 14 drives the rotor 12.

The storage battery unit 30 includes, for example, a storage battery 32, a BMU (Battery Management Unit) 34, and a detection unit 36. The storage battery 32 is, for example, a battery pack in which multiple battery cells are connected in series, parallel, or series-parallel. The battery cells that make up the storage battery 32 are, for example, secondary batteries that can be repeatedly charged and discharged, such as lithium-ion batteries (LIBs) or nickel-metal hydride batteries.

The connection unit 33 is connected to the generator 50 via the storage battery 32, the first control circuit 20, and the second control circuit 40. The connection unit 33 is controlled by the control device 100, and selectively supplies power to the first control circuit 20 from one or both of the storage battery 32 and the generator 50. The connection unit 33 includes, for example, a DC-DC converter, and boosts the output potential of the storage battery 32 so that power is supplied exclusively from the storage battery 32 to the first control circuit 20. By preventing power from being supplied from the generator 50 and suppressing the boost, power is supplied from the generator 50 to the first control circuit 20. The connection unit 33 may also realize the same function as above by, for example, a switch.

The BMU 34 performs cell balancing, abnormality detection of the storage battery 32, deriving the cell temperature of the storage battery 32, deriving the charge/discharge current of the storage battery 32, estimating the SOC of the storage battery 32, etc. The detection unit 36 is a voltage sensor, a current sensor, a temperature sensor, etc. for measuring the state of charge of the storage battery 32. The detection unit 36 outputs the measurement results of the measured voltage, current, temperature, etc. to the BMU 34.

The flying object 1 may include multiple storage battery units 30. For example, storage battery units 30 corresponding to each of the first and second configurations may be provided. Note that, although in this embodiment, the power generated by the generator 50 is supplied to the storage battery 32, it may also be supplied to the first control circuit 20 and the electric motor 14 without passing through the storage battery 32 (or selectively through the storage battery 32).

The second control circuit 40 is a PCU (Power Conditioning Unit) that includes a converter and the like. The second control circuit 40 converts the AC power generated by the generator 50 into DC power and supplies the converted power to the storage battery 32 and/or the first control circuit 20.

The generator 50 is connected to the output shaft of the GT 60. The generator 50 is driven by the operation of the GT 60, and generates AC power by this drive. The generator 50 may be connected to the output shaft of the GT 60 via a reduction mechanism. The generator 50 functions as a motor, and when the supply of fuel to the GT 60 is stopped, it rotates (idles) the GT 60 to make it operable. At that time, the second control circuit 40 takes power from the storage battery 32 side to motor the generator 50. Instead of the above functional configuration, a starter motor may be connected to the output shaft of the GT 60, and the starter motor may make the GT 60 operable.

The GT60 is, for example, a turboshaft engine. The GT60 includes, for example, an intake port, a compressor, a combustion chamber, a turbine, and the like, all of which are not shown. The compressor compresses the intake air drawn in through the intake port. The combustion chamber is located downstream of the compressor and burns a mixture of compressed air and fuel to generate combustion gas. The turbine is connected to the compressor and rotates together with the compressor by the force of the combustion gas. The output shaft of the turbine rotates as described above, operating the generator 50 connected to the output shaft of the turbine.

The control device 100 is realized by, for example, a hardware processor such as a CPU (Central Processing Unit) executing a program (software). Some or all of the functions of the control device 100 may be realized by hardware (including circuitry) such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a GPU (Graphics Processing Unit), or may be realized by a combination of software and hardware. The program may be stored in advance in a storage device (storage device with a non-transient storage medium) such as an HDD (Hard Disk Drive) or flash memory of the control device 100, or may be stored in a removable storage medium such as a DVD or CD-ROM, and installed in the HDD or flash memory of the control device 100 by mounting the storage medium (non-transient storage medium) in a drive device.

The various sensors 120 include, for example, a rotation speed sensor, multiple temperature sensors, multiple pressure sensors, a lubricant sensor, an altitude sensor, and a gyro sensor. The rotation speed sensor detects the rotation speed of the turbine. The temperature sensor detects the temperature near the intake port of the GT60 and the temperature near the downstream of the combustion chamber. The lubricant sensor detects the temperature of the lubricant supplied to the bearings of the GT60, etc. The pressure sensor detects the pressure inside the container that houses the control device 100 and the pressure near the intake port of the GT60. The altitude sensor detects the altitude of the flying object 1. The gyro sensor detects the attitude of the aircraft 10.

The control device 100 controls the above-mentioned electric motor 14, first control circuit 20, storage battery unit 30, second control circuit 40, generator 50, GT 60, etc. based on their operating states or information acquired from various sensors 120. For example, the control device 100 controls each of the above-mentioned functional configurations to cause the aircraft 1 to take off or land, or fly the aircraft 1 in a specified flight state.

The control device 100 controls the flying object 1 based on the flight information. The flight information is, for example, information obtained from the detection results of the various sensors 120 and the flight state of the flying object 1 according to the control signal.

Figure 3 is a diagram for explaining the flight states of the aircraft 1. As shown in Figure 3, the aircraft 1 (1) taxis, (2) takes off and hovers, (3) ascends and accelerates, and (4) cruises. The aircraft 1 then (5) descends and decelerates, (6) hovers, lands, and (7) taxis, refuels, and parks. "Takeoff" is an example of the first state in the claims, "cruise" is an example of the second state in the claims, and "landing" is an example of the third state in the claims. "Cruise" refers to a flight state in which the altitude change is small, and more specifically, a state in which no intentional altitude change is made. In contrast, "takeoff" and "landing" are flight states in which the altitude change is larger than "cruise". The first and third states are also states in which power consumption is large, i.e., the load is large, compared to the second state. The other flight conditions may be defined as corresponding to the first condition, the second condition, the third condition, or none of the above.

When the flight state is the first state or the third state, the control device 100 controls the connection unit 33 so that power is supplied only from the storage battery 32. When the flight state is the second state, the control device 100 controls the connection unit 33 so that power is supplied only from the generator 50. Therefore, the storage battery 32 needs to be charged with the amount of charge consumed in the first state before the first state, and the amount of charge consumed in the third state needs to be charged with the amount of charge consumed in the third state before the third state.

The control device 100 sets the charge amount of the storage battery 32 before the first state. This charge amount is determined based on conditions such as the planned duration of the first state. When the first state ends, this charge amount of the storage battery 32 decreases to a charge amount within the first charge range. The first charge range is, for example, a range in which the SOC of the storage battery 32 is between 5% and 10%.

Furthermore, in the second state, the electric motor 14 is operated with power supplied only from the generator 50, and the storage battery 32 is charged with power supplied from the generator 50. The charge amount required in the second state is set so that the charge amount of the storage battery 32 is within the second charge range when the third state ends. The second charge range is, for example, a range in which the SOC of the storage battery 32 is 3% or more and 7% or less.

[Flowchart (in-flight control)]

Figure 4 is a flowchart showing an example of the flow of processing executed by the control device 100. First, the control device 100 acquires the flight state of the flying object 1 (step S100). Next, the control device 100 determines whether the flight state is the first state or the third state (step S102). If the flight state is the first state or the third state, the control device 100 controls the connection unit 33 to supply power to the electric motor 14 only from the storage battery 32 (step S104). If the flight state is neither the first state nor the third state, that is, if the flight state is the second state, the control device 100 controls the connection unit 33 to supply power to the electric motor 14 only from the generator 50 (step S106). In addition, the control device 100 controls the connection unit 33 to charge the storage battery 32 with the power supplied by the generator 50 (step S108). The processing of this flowchart is executed repeatedly, for example, at a predetermined interval.

After the aircraft 1 has landed, the storage battery 32 can be charged using an external power source or a generator 50. After charging is complete, the aircraft 1 can take off and fly again.

As described above, the aircraft 1 according to the first embodiment only needs to be equipped with the storage batteries required for the first and third states, which allows the weight of the aircraft 1 to be reduced and the payload to be increased.

Second Embodiment
The second embodiment will be described below. In the first embodiment, when the flight state is the first state or the third state, power is supplied only from the storage battery, whereas in the second embodiment, when the flight state is the first state or the third state, power is supplied from the storage battery and the generator.

FIG. 5 is a flowchart showing an example of the flow of processing executed by the control device 100.
First, the control device 100 acquires the flight state of the flying object 1 (step S200). Next, the control device 100 determines whether the flight state is the first state or the third state (step S202). If the flight state is the first state or the third state, the control device 100 controls the connection unit 33 so that power is supplied to the electric motor 14 by the generator 50 and the storage battery 32 (step S204). If the flight state is neither the first state nor the third state, that is, if the flight state is the second state, the control device 100 controls the connection unit 33 so that power is supplied to the electric motor 14 only by the generator 50 (step S206). In addition, the control device 100 controls the connection unit 33 so that the storage battery 32 is charged by the power supplied by the generator 50 (step S208). The process of this flowchart is executed repeatedly, for example, at a predetermined interval.

As described above, unlike the aircraft 1 according to the first embodiment, the aircraft 1 according to the second embodiment can further reduce the storage battery by using the generator 50 even in the first and third states.

The above describes the form for carrying out the present invention using an embodiment, but the present invention is not limited to such an embodiment, and various modifications and substitutions can be made without departing from the spirit of the present invention.

The lower limits of the first and second charging ranges may be set to values at which the SOC of the storage battery 32 is 0%. This allows the storage battery 32 to have no charge remaining at the end of the first and third states, further reducing the storage battery.

The control device 100 may control the connection unit 33 so that only the generator 50 supplies power to the electric motor when the generator 50 is available, and may control the connection unit 33 so that only the storage battery 32 supplies power to the electric motor 14 when the generator 50 is unavailable. The charge amount of the storage battery 32 may be set so that the storage battery 32 maintains a charge amount equal to or greater than a third threshold after landing when the generator 50 is unavailable. The third threshold is, for example, a charge amount at which the SOC of the storage battery 32 becomes 5%.
This allows the storage battery 32 to be minimized, and also makes it unnecessary to have a cooling system since the storage battery 32 is only used when the generator 50 is unavailable.

1: Aircraft, 10: Airframe, 12: Rotor, 14: Electric motor, 16: Arm, 20: First control circuit, 30: Battery unit, 32: Battery, 34: Battery Management Unit (BMU), 36: Detection unit, 40: Second control circuit, 50: Generator, 60: Gas turbine engine (GT), 100: Control device, 120: Various sensors

Claims (5)

an engine mounted on an aircraft fuselage;
a generator connected to an engine shaft of the engine;
A storage battery that stores the electric power generated by the generator;
A charge amount detection unit that detects a charge state of the storage battery;
an electric motor driven by electric power supplied from the generator and the storage battery;
a rotor driven by a driving force output by the electric motor;
a control unit that controls a connection unit that connects the storage battery and the electric motor to thereby control power supplied from the storage battery to the electric motor;
An aircraft propulsion system comprising:
The control unit is
When a flight state of the aircraft changes from a first state, through a second state, to a third state,
setting a charge amount of the storage battery before the first state such that a charge state of the storage battery at the time when the first state ends is within a first charging range;
controlling the connection unit such that power is supplied to the electric motor exclusively from the storage battery during the first flight state;
controlling the connection such that power is supplied to the electric motor exclusively from the generator during the second flight state;
controlling the connection unit so that, while the flight state is in the second state, the electric power generated by the generator is supplied to the storage battery such that the charge amount of the storage battery is within a second charging range at the time when the third state ends;
controlling the connection unit so that power is supplied to the electric motor exclusively from the storage battery while the flight state is the third state;
The second state is a state in which the altitude change is smaller than those of the first state and the third state.
Aircraft propulsion systems. an engine mounted on an aircraft fuselage;
a generator connected to an engine shaft of the engine;
A storage battery that stores the electric power generated by the generator;
A charge amount detection unit that detects a charge state of the storage battery;
an electric motor driven by electric power supplied from the generator and the storage battery;
a rotor driven by a driving force output by the electric motor;
a control unit that controls a connection unit that connects the storage battery and the electric motor to thereby control power supplied from the storage battery to the electric motor;
An aircraft propulsion system comprising:
The control unit is
When a flight state of the aircraft changes from a first state, through a second state, to a third state,
setting a charge amount of the storage battery before the first state such that a charge state of the storage battery at the time when the first state ends is within a first charging range;
controlling the connection unit so that power is supplied from the generator and the battery to the electric motor while the flight state is the first state;
controlling the connection such that power is supplied to the electric motor exclusively from the generator during the second flight state;
controlling the connection unit so that, while the flight state is in the second state, the electric power generated by the generator is supplied to the storage battery such that the charge amount of the storage battery is within a second charging range at the time when the third state ends;
controlling the connection unit so that power is supplied from the generator and the battery to the electric motor while the flight state is the third state;
The second state is a state in which the altitude change is smaller than those of the first state and the third state.
Aircraft propulsion systems. The lower limit values of the first charging range and the second charging range are both zero.
3. An aircraft propulsion system according to claim 1 or 2. Before the aircraft takes off, the storage battery is charged to the set charge level by power supplied from an external ground power source or by power generated by the generator.
An aircraft propulsion system according to any one of claims 1 to 3. The control unit is
controlling the connection so that, when the generator is available, power is supplied to the electric motor exclusively from the generator;
When the generator is unavailable, the connection unit is controlled so that power is supplied to the electric motor only from the storage battery;
The charge amount of the storage battery is set to maintain a charge amount equal to or greater than a third threshold when the aircraft lands.
An aircraft propulsion system according to any one of claims 1 to 4 .

Images