Structure of a distributed airborne megawatt-class high-voltage DC generator

Abstract

This patent belongs to the aviation field and relates to the structure of a distributed airborne megawatt-class high-voltage DC generator, solving the problem of installing a high-power generator on an accessory housing. The structure includes: a three-stage AC generator and external components; the three-stage AC generator is mounted on the accessory housing, and the external components are installed in the fuselage outside the accessory housing. This invention is applicable to airborne megawatt-class generators.

Description

Technical Field

[0001] This patent belongs to the field of aviation and relates to the structure of a distributed airborne megawatt-level high-voltage DC generator. Background Technology

[0002] With the development of multi-electric technology in airborne systems, electricity is being used to replace hydraulic and air-cooled systems in airborne secondary energy sources. This has increased the power demand of airborne systems from tens of kilowatts to hundreds of kilowatts, and the power supply voltage has increased from 115V AC to 270V DC. Research into electric propulsion technology aims to replace the engine with a generator for aircraft propulsion, further increasing power demand to the megawatt level. To meet this significant increase in power requirements, the transmission capacity of airborne generators needs to be substantially increased, along with their size and weight. Furthermore, generators need to provide higher voltages.

[0003] The airborne generator is driven by the engine and mounted on the engine accessory housing using a cantilever beam configuration. It connects to the accessory housing's flange via the generator's flange and is driven by the accessory housing's drive shaft. Because the space for mounting the generator on the accessory housing is limited, and the weight of airborne equipment must be strictly controlled, the size and weight of a high-power generator cannot be proportionally increased with the increase in power; these factors must be strictly controlled.

[0004] Generators convert the mechanical energy provided by the engine into electrical energy through electromagnetic fields. High-voltage DC generators typically have an efficiency of around 80%, meaning that about 20% of the mechanical energy is converted into heat during the process. As the generator's power increases, the power required for heat dissipation also increases. Because oil-cooled systems have a much stronger heat dissipation capacity than air-cooled systems, and oil cooling also solves the heat dissipation difficulties of air-cooled generators in the thin air at high altitudes, oil-cooled generators are much smaller. Therefore, high-power generators typically use oil cooling. The oil pump in the generator's oil cooling system is integrated inside the generator and rotates synchronously with the generator's rotor, causing the cooling oil inside the generator to flow, thereby cooling the generator. As the generator's power increases, the power required for heat dissipation also increases, so the oil pump also needs to be enlarged.

[0005] Aircraft employing multiple electric technologies and electric propulsion technologies require high-power generators to provide high-voltage direct current to electrical equipment to control the speed of electric motors. Since generators output alternating current, they need to be equipped with rectifiers. These rectifiers also require cooling oil. Therefore, high-power generators typically integrate rectifiers and are cooled together with the generator's oil cooling system.

[0006] According to current design principles for high-power generators, in addition to the generator's stator and rotor, a cooling oil pump and rectifier need to be integrated. As generator power increases, the generator size also increases, while the installation space on the accessory housing is limited. The increased weight of the generator, especially with cantilever beam mounting, significantly increases the suspension torque. Ultimately, the size and installation method of the accessory housing limit the size and weight of the generator, making it difficult to install and use even larger power generators. (See the functional block diagram of a traditional generator.) Figure 1 . Summary of the Invention

[0007] The purpose of this invention is to provide a structure for a distributed airborne megawatt-level high-voltage DC generator, solving the problem of installing a high-power generator on an accessory casing.

[0008] The technical solution of this invention:

[0009] The structure of a distributed airborne megawatt-class high-voltage DC generator includes: a three-stage AC generator and external components;

[0010] The three-stage alternator is mounted on the accessory housing, while external components are installed inside the main unit, outside the accessory housing.

[0011] The three-stage AC generator includes: a drive shaft cooling pump 4 and a permanent magnet cooling pump 1, an exciter cooling pump 2, and a main generator cooling pump 3, which are sequentially installed on the drive shaft cooling pump 4; the drive shaft cooling pump 4 drives the permanent magnet cooling pump 1, the exciter cooling pump 2, and the main generator cooling pump 3.

[0012] The external components include: rectifier cooling pump 5, cooling pump 6, and motor cooling pump 7.

[0013] The rectifier cooling pump 5 receives AC power from the main generator cooling pump 3 and rectifies it into DC power to supply power to the electrical equipment; the motor cooling pump 7 receives frequency-converted AC power from the permanent magnet cooling pump 1 and drives the cooling pump 6 to rotate; the cooling pump 6 provides circulating cooling oil to the permanent magnet cooling pump 1, the exciter cooling pump 2, the main generator cooling pump 3 and the rectifier cooling pump 4 through cooling pipes to cool and reduce the temperature of these components.

[0014] External components are integrated into the generator rectifier and cooling components.

[0015] The speed changes of the permanent magnet motor cooling pump 1, the electric motor driving the cooling pump 7, the cooling pump and the cooling pump 6 are synchronized with the speed changes of the drive shaft cooling pump 4.

[0016] The electric motor cooling pump 7 uses a permanent magnet motor.

[0017] The main generator cooling pump 3 is for megawatt-class generators.

[0018] The main generator cooling pump 3 adopts multi-winding technology.

[0019] The main generator cooling pump 3 operates at 500 volts.

[0020] The cooling medium for the cooling pump 6 is lubricating oil or liquid nitrogen.

[0021] The beneficial effects of this invention: Increased generator power inevitably leads to increased size and weight. If the size and weight of a generator integrating too many functions exceed the capacity of the accessory housing, a high-power generator cannot be installed, resulting in the inability to use high-power airborne electrical equipment and hindering aircraft technological development. The solution of this invention is to decompose and simplify generator functions, and to externalize the generator rectifier and cooling oil pump, thereby reducing the size and weight of the generator mounted on the accessory housing and solving the problem of installing a high-power generator on the accessory housing. Attached Figure Description

[0022] Figure 1 This is a functional block diagram of a traditional three-stage DC generator.

[0023] Figure 2 This is a functional block diagram of a distributed three-stage generator system. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] In a traditional three-stage DC generator, there are four cooling pumps: permanent magnet motor cooling pump 1, exciter cooling pump 2, main generator cooling pump 3, drive shaft cooling pump 4, rectifier cooling pump 5, and cooling pump 6. Drive shaft cooling pump 4 drives permanent magnet motor cooling pump 1, exciter cooling pump 2, main generator cooling pump 3, and cooling pump 6, which convert mechanical energy into alternating current (AC). Rectifier cooling pump 5 rectifies the AC into DC to supply power to the electrical equipment. Cooling pump 6 provides circulating cooling oil to permanent magnet motor cooling pump 1, exciter cooling pump 2, main generator cooling pump 3, and rectifier cooling pump 4 to cool these components.

[0026] By simplifying the generator's functions, reducing its size, and lowering its weight based on the traditional layout, the problem of installing a high-power generator on the accessory housing can be solved. However, an external rectifier and cooling oil pump are still required. The specific solution is as follows.

[0027] a) Simplify generator functions

[0028] The generator retains the stator and rotor components, but no longer integrates the rectifier and cooling pump. It only retains the components that convert mechanical energy into electrical energy, retains the necessary oil cooling system, and reduces the size and weight of the generator by reducing the size of the internal cooling oil tank.

[0029] b) External rectifier and cooling pump

[0030] The generator rectifier and cooling pump are moved externally and are no longer integrated into the generator. These components are not directly related to the generator's function of converting mechanical energy into electrical energy, so they can be separated from the generator and not installed on the accessory housing.

[0031] c) The cooling pump is driven by a permanent magnet motor inside the generator.

[0032] Originally, the internal cooling pump of the generator rotated synchronously with the generator rotor and was a mechanical pump. The external cooling pump is now driven by an electric motor. To synchronize with the generator, the electric motor is powered by a permanent magnet motor inside the generator. The frequency change of the AC output of the permanent magnet motor is synchronized with the change in generator speed. Therefore, the speed changes of the electric motor cooling pump 7 and cooling pump 6 driven by the permanent magnet motor are synchronized with the speed change of the drive shaft cooling pump 4. The electric motor cooling pump 7 uses a permanent magnet motor. The main generator cooling pump 3 is for a megawatt-class generator. The main generator cooling pump 3 uses multi-winding technology to reduce the power of a single rectifier bridge in the rectifier cooling pump 4. The voltage of the main generator cooling pump 3 has been increased from 115 volts to 500 volts. The cooling medium for cooling pump 6 is lubricating oil or liquid nitrogen.

[0033] like Figure 2 As shown, in the distributed three-stage generator system of this invention, the three-stage AC generator only includes a permanent magnet motor cooling pump 1, an exciter cooling pump 2, a main generator cooling pump 3, and a drive shaft cooling pump 4. The rectifier and cooling pumps are separated and integrated into the generator rectifier and cooling assembly, including a rectifier cooling pump 5, a cooling pump 6, and a motor cooling pump 7. In the three-stage AC generator, the drive shaft cooling pump 4 drives the permanent magnet motor cooling pump 1, the exciter cooling pump 2, and the main generator cooling pump 3, which convert mechanical energy into alternating current. In the generator rectifier and cooling assembly, the rectifier cooling pump 5 receives AC power from the three-stage generator and rectifies it into DC power to supply power to the electrical equipment; the motor cooling pump 7 receives frequency-converted AC power from the permanent magnet motor cooling pump 1 and drives the cooling pump 6 to rotate; the cooling pump 6 provides circulating cooling oil to the permanent magnet motor cooling pump 1, the exciter cooling pump 2, the main generator cooling pump 3, and the rectifier cooling pump 4 through cooling pipes to cool and reduce the temperature of these components.

[0034] Compared to traditional airborne generators, the distributed three-stage generator system externalizes the rectifier cooling pumps 5 and 6. The three-stage generator mounted on the accessory housing retains only the permanent magnet cooling pump 1, exciter cooling pump 2, main generator cooling pump 3, and drive shaft cooling pump 4, while retaining the function of converting mechanical energy into electrical energy. This simplification significantly reduces the generator's size and weight. Larger-power generators can be installed on accessory housings with size and weight limitations.

[0035] The external generator rectifier and cooling assembly receives the multiphase AC power supplied by the generator, and rectifies it into high-voltage DC power through the rectifier cooling pump 5 to supply power to the high-power equipment on the air.

[0036] The external cooling pump 6 is driven by the electric motor cooling pump 7. The electrical energy that drives the electric motor cooling pump 7 comes from the permanent magnet motor cooling pump 1 in the three-stage generator. The frequency of the AC power output by the permanent magnet motor cooling pump 1 is linearly related to the speed of the generator. The speed of the electric motor cooling pump 7 is also linearly related to the frequency of the AC power. Therefore, the speed of the cooling pump 6 is synchronized with that of the generator, which is the same as the speed of the mechanical cooling pump originally integrated inside the generator.

[0037] By simplifying generator functions and using external rectifiers and cooling pumps, the size and weight of the generator can be reduced. This allows for the installation of a more powerful generator within the limited space of the accessory housing, providing greater electrical power to the aircraft and laying the foundation for the development of multi-electric and electric propulsion technologies for aircraft. A functional block diagram of the distributed generator is shown below. Figure 2 .

[0038] Megawatt-class generators represent the future of power system development. They represent more than just increased power and voltage; traditional generator technology will face greater challenges and require new design approaches.

[0039] The above description is merely a specific embodiment of the present invention, providing a detailed description of the invention. Parts not covered herein are conventional techniques. However, the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. The structure of a distributed airborne megawatt-class high-voltage DC generator, characterized in that, include: Three-stage alternator and external components; The three-stage alternator is mounted on the accessory housing, while external components are installed inside the main unit, outside the accessory housing. The three-stage AC generator includes: a drive shaft (4) and a permanent magnet motor (1), an exciter (2), and a main generator (3) sequentially mounted on the drive shaft (4); the drive shaft (4) drives the permanent magnet motor (1), the exciter (2), and the main generator (3); The external components include: a rectifier (5), a cooling pump (6), and a motor (7); The rectifier (5) receives AC power from the main generator (3) and rectifies it into DC power to supply power to the electrical equipment; the motor (7) receives AC power from the permanent magnet (1) and drives the cooling pump (6) to rotate; the cooling pump (6) provides circulating cooling oil to the permanent magnet (1), exciter (2), main generator (3) and rectifier (5) through the cooling pipeline to cool these components.

2. The structure of a distributed airborne megawatt-level high-voltage DC generator as described in claim 1, characterized in that, External components are integrated into the generator rectifier and cooling components.

3. The structure of a distributed airborne megawatt-level high-voltage DC generator as described in claim 1, characterized in that, The speed changes of the motor (7) and cooling pump (6) driven by the permanent magnet motor (1) are synchronized with the speed changes of the transmission shaft (4).

4. The structure of a distributed airborne megawatt-level high-voltage DC generator as described in claim 1, characterized in that, The electric motor (7) is a permanent magnet motor.

5. The structure of a distributed airborne megawatt-level high-voltage DC generator as described in claim 1, characterized in that, The main generator (3) is a megawatt-class generator.

6. The structure of a distributed airborne megawatt-level high-voltage DC generator as described in claim 1, characterized in that, The main generator (3) adopts multi-winding technology.

7. The structure of a distributed airborne megawatt-level high-voltage DC generator as described in claim 1, characterized in that, The voltage of the main generator (3) is 500 volts.

8. The structure of a distributed airborne megawatt-level high-voltage DC generator as described in claim 1, characterized in that, The cooling medium of the cooling pump (6) is lubricating oil or liquid nitrogen.

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