Electric compressor system and cooling method thereof

Abstract

The invention relates to the technical field of aviation equipment, in particular to an electric gas compressor system and a cooling method thereof.The electric gas compressor system comprises a heat insulation cover and further comprises a gas compressor, a motor, a turbine, a first heat exchanger and a second heat exchanger which are fixed in the heat insulation cover; the outlet is communicated with a hot side runner inlet of the second heat exchanger; a hot side runner outlet of the second heat exchanger is communicated with an inner cavity of a shell of the motor through a cooling air channel, and the cavity is communicated with an airflow inlet of the turbine; the air compressor, the motor, the turbine and the two-stage heat exchanger are integrated in the heat insulation cover, open type cooling circulation without an external cold source is constructed, self-cooling of the motor and a bearing is achieved, a relatively low-temperature environment is built in the heat insulation cover, and the problem that an existing electric air compressor generally lacks effective self-cooling capacity, and the service life of the air compressor is prolonged is solved. And active heat management cannot be carried out on heat-sensitive parts such as motor windings and bearings by utilizing own airflow.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aviation equipment, and in particular to an electric compressor system and a cooling method thereof. BACKGROUND

[0002] The electric compressor system is a power device driven by an electric motor to rotate a compressor impeller, pressurize and supply airflow to onboard equipment, and is widely used in high-altitude and high-Mach number aircraft to provide stable air source for engine accessories, environmental control systems, electronic cabins or sealed cavities. For example, a compressor structure with an embedded coaxial motor is disclosed in the prior art (authorized publication number CN205779789U).

[0003] However, under high-altitude and high-Mach number flight conditions, the ram air stagnation temperature can reach 900 K or more, and the internal working environment of the electric compressor is extremely harsh after the electric compressor inhales and compresses the air. The existing electric compressor generally lacks effective self-cooling capability and cannot actively manage the heat of heat-sensitive components such as motor windings and bearings using its own airflow. SUMMARY

[0004] Therefore, the present application provides an electric compressor system and a cooling method thereof, which integrates a compressor, a motor, a turbine and two-stage heat exchangers in a heat shield to build an open cooling cycle without external cooling sources, realize self-cooling of the motor and bearings, and create a relatively low-temperature environment in the heat shield, solving the problem that the existing electric compressor generally lacks effective self-cooling capability and cannot actively manage the heat of heat-sensitive components such as motor windings and bearings using its own airflow.

[0005] The technical solution of the present application is as follows: On the one hand, the present application provides an electric compressor system comprising a heat shield, and further comprising a compressor, a motor, a turbine, a first heat exchanger and a second heat exchanger fixed inside the heat shield, wherein, The impeller of the compressor, the rotor of the motor and the impeller of the turbine are coaxially connected to form a coaxial rotor assembly; The cold side flow passage inlet of the first heat exchanger is in communication with a ram air inlet provided on the heat shield, and the outlet is in communication with the airflow inlet of the compressor; The hot side flow passage inlet of the first heat exchanger is in communication with the outlet flow path of the compressor, and the outlet is in communication with the hot side flow passage inlet of the second heat exchanger; The hot side flow passage outlet of the second heat exchanger is in communication with the internal cavity of the motor shell through a cooling gas passage, and the cavity is in communication with the airflow inlet of the turbine; The gas flow outlet of the turbine is communicated with the cold side flow channel inlet of the second heat exchanger, the cold side flow channel outlet of the second heat exchanger is communicated with the inside of the heat shield, and the heat shield is provided with an exhaust port.

[0006] On the basis of the above technical scheme, preferably, the outlet flow path of the compressor comprises a main flow path and a branch flow path, wherein, The main flow path penetrates through the heat shield and is used for supplying gas to downstream equipment; The branch flow path is communicated with the hot side flow channel of the first heat exchanger.

[0007] On the basis of the above technical scheme, preferably, the first heat exchanger and the second heat exchanger are both cross-flow air-air heat exchangers.

[0008] On the basis of the above technical scheme, preferably, a spiral air channel is arranged on the shell of the motor, and a communication hole is arranged on the side of the cavity, wherein, One end of the spiral air channel is communicated with the cavity through the communication hole, and the other end is communicated with the gas flow inlet of the turbine.

[0009] On the basis of the above technical scheme, preferably, the compressor is arranged at the front end of the shell of the motor, and the turbine is arranged at the rear end of the shell of the motor, wherein, The front end and the rear end of the shell of the motor are both provided with shaft holes, One end of the rotor of the motor extends into the shell of the compressor through the shaft hole at the front end, and the other end extends into the shell of the turbine through the shaft hole at the rear end; Radial bearings are arranged in the two shaft holes, and the radial bearings are arranged on the rotor of the motor; An axial sealing disc is arranged in the shaft hole at the front end, and is used for sealing the cooperation gap between the rotor of the motor and the shaft hole; The radial bearings have bearing clearances, and the gas flow in the cavity flows into the inside of the shell of the turbine through the bearing clearances of the radial bearings at the rear end.

[0010] On the basis of the above technical scheme, preferably, a thrust bearing is coaxially arranged at the front end of the impeller of the turbine, wherein, The thrust bearing is sleeved on the outer periphery of the rotor of the motor, and the front end of the thrust bearing abuts against the rear end of the shell of the motor; The thrust bearing has a bearing clearance, and the shaft hole at the rear end is communicated with the inside of the shell of the turbine through the bearing clearance of the thrust bearing.

[0011] On the basis of the above technical scheme, preferably, an annular flow guide cavity is coaxially arranged on the shell of the turbine along the circumference of the impeller of the turbine, wherein, The ring-shaped flow guide cavity is provided with an opening at the front end, forming an air inlet of the turbine; The inner ring of the ring-shaped flow guide cavity is provided with a plurality of flow guide holes in the circumferential direction, and the airflow in the ring-shaped flow guide cavity is injected to the impeller of the turbine through the flow guide holes.

[0012] In another aspect, the application also provides a cooling method of an electric turbocharger system, applied to the electric turbocharger system, comprising the following steps: S1, ram air enters the cold side flow channel of the first heat exchanger through the ram air inlet on the heat shield, and then enters the compressor for pressurization; S2, part of the exhaust gas of the compressor is introduced into the hot side flow channel of the first heat exchanger, and exchanges heat with the ram air in the cold side flow channel of the first heat exchanger to preliminarily cool the ram air; S3, the preliminarily cooled airflow is introduced into the hot side flow channel of the second heat exchanger, and exchanges heat with the cold side airflow from the turbine exhaust to deeply cool the airflow; S4, the deeply cooled airflow is introduced into the cavity inside the motor through the cooling gas passage to cool the components inside the motor; S5, the cooled airflow is guided to enter the turbine to expand and do work; S6, the low-temperature airflow discharged from the turbine is introduced into the cold side flow channel of the second heat exchanger to cool the airflow in the hot side flow channel of the second heat exchanger, and then is discharged into the heat shield and is discharged through the exhaust port.

[0013] On the basis of the above technical scheme, preferably, the cooling gas passage is provided with a control valve for adjusting the cooling gas flow entering the motor.

[0014] On the basis of the above technical scheme, preferably, the opening degree of the control valve is adjusted according to the motor temperature or the bearing temperature: When the bearing temperature is lower than a preset lower limit T1, the opening degree is reduced to reduce the cooling gas flow, so that the bearing temperature rises; When the bearing temperature is higher than a preset upper limit T2, the opening degree is increased to increase the cooling gas flow, so that the bearing temperature is reduced; When the motor temperature exceeds a safety threshold TS, the speed of the motor is reduced, so that the motor temperature falls below the safety threshold TS.

[0015] The electric turbocharger system and the cooling method thereof have the following beneficial effects: By integrating the compressor, motor, turbine and two-stage heat exchanger inside the heat shield, an open cooling circulation system is constructed without relying on external cold sources. The system uses compressor exhaust to drive the cooling process, and recovers the cold energy of the low-temperature exhaust gas after the turbine expansion work, achieving efficient self-cooling of the motor winding, bearing and other key components. At the same time, the cooled exhaust gas is discharged into the heat shield, forming a low-temperature microenvironment inside the shield relative to the external environment, effectively isolating the high-temperature ram air brought by high Mach number flight, significantly improving the self-cooling effect and overall reliability of the system.

[0016] By setting a spiral air duct on the motor housing and communicating with the motor cavity through a communication hole, the cooling gas flows along the spiral path in the motor housing, prolonging the heat exchange path and enhancing the cooling uniformity of the motor housing, effectively suppressing the formation of local hot spots and improving the safety and stability of the motor operation.

[0017] By arranging the compressor at the front end of the motor and the turbine at the rear end of the motor, and setting shaft holes with radial bearings at the front and rear ends of the motor housing, the front end is configured with an axial sealing disc to block the intrusion of high-temperature gas, and the rear end uses the radial bearing gap to guide the cooling gas into the turbine. This structure not only realizes a compact coaxial layout, but also builds a reliable cooling gas flow channel from the motor cavity to the turbine, while ensuring the rotor support and sealing performance. In addition, a thrust bearing is provided at the front end of the turbine impeller, which is sleeved on the outer periphery of the rotor and abuts against the rear end of the motor housing. Not only does it bear the axial load, but its bearing gap also serves as a channel for cooling gas to enter the turbine, realizing an integrated design of structure bearing and gas flow passage, simplifying the flow channel structure and improving the compactness and reliability of the system.

[0018] By setting an annular flow guide cavity on the turbine housing and injecting gas flow into the impeller through the circumferentially distributed flow guide holes, the circumferential uniformity and flow stability of the turbine inlet gas are improved, and the turbine expansion work efficiency is improved. This not only enhances the energy recovery capability of the entire cooling cycle, but also further optimizes the thermal management and power output performance of the system, ensuring the efficient and stable operation of the electric compressor system under high Mach number flight conditions. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0020] Figure 1 is a structural schematic diagram of an electric compressor system of the present application; Figure 2 isFigure 1 Schematic diagram of a local structure Figure 3 This is a diagram showing the direction of airflow. Figure 4 For flow control diagrams; In the diagram: 1. Heat shield; 2. Compressor; 3. Motor; 4. Turbine; 5. First heat exchanger; 6. Second heat exchanger; 7. Cooling air passage; 8. Control valve; 31. Radial bearing; 32. Axial sealing disc; 33. Thrust bearing; 101. Ram air inlet; 102. Exhaust port; 201. Main flow path; 202. Branch flow path; 301. Cavity; 302. Spiral air passage; 303. Shaft hole; 401. Annular guide cavity; 3011. Connecting hole; 4011. Guide hole. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0022] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0023] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0025] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0026] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. Additionally, examples of various specific processes and materials are provided in this invention; however, those skilled in the art will recognize the applicability of other processes and / or the use of other materials.

[0027] like Figures 1-4 As shown, an electric compressor system of the present invention includes a heat shield 1, and a compressor 2, a motor 3, a turbine 4, a first heat exchanger 5, and a second heat exchanger 6 fixed inside the heat shield 1. The impeller of the compressor 2, the rotor of the motor 3, and the impeller of the turbine 4 are coaxially connected to form a coaxial rotor assembly, achieving a compact structure and efficient power transmission.

[0028] The first heat exchanger 5 and the second heat exchanger 6 are both any one of the cross-flow air-air heat exchangers in the prior art, which is a device using air as a heat exchange medium to realize heat energy recovery by transferring the heat of high-temperature air to low-temperature air. The cold side flow passage of the first heat exchanger 5 is in communication with the ram air inlet 101 arranged on the heat shield 1 at one end and in communication with the airflow inlet of the air compressor 2 at the other end. The hot side flow passage of the first heat exchanger 5 is in communication with the outlet flow path of the air compressor 2 at one end and in communication with the hot side flow passage of the second heat exchanger 6 through a pipeline at the other end. The hot side flow passage outlet of the second heat exchanger 6 is in communication with the internal cavity 301 of the shell of the motor 3 through the cooling gas passage 7, and the cavity 301 is in communication with the airflow inlet of the turbine 4. The airflow outlet of the turbine 4 is in communication with the cold side flow passage of the second heat exchanger 6, and the cold side flow passage outlet of the second heat exchanger 6 is in communication with the inside of the heat shield 1, which is provided with an exhaust port 102 for discharging excess gas.

[0029] In the structure, the outlet flow path of the air compressor 2 includes a main flow path 201 and a branch flow path 202. The main flow path 201 penetrates through the heat shield 1 to provide a pressurized air source to the downstream equipment. The branch flow path 202 is in communication with the hot side flow passage of the first heat exchanger 5 to guide part of the exhaust gas of the air compressor 2 to the first heat exchanger 5 as the air source of the cooling cycle.

[0030] As shown in the dashed arrows in FIG. 1, Figure 1 Figure 1 During system operation, the ram air enters the air compressor 2 through the ram air inlet 101, the cold side flow passage of the first heat exchanger 5, and the hot side flow passage of the second heat exchanger 6 in sequence to be pressurized and discharged. The exhaust gas is divided into two paths. One path is output to the downstream equipment through the main flow path 201, and the other path enters the hot side flow passage of the first heat exchanger 5 through the branch flow path 202 to exchange heat with the ram air passing through the cold side flow passage of the first heat exchanger 5, thereby achieving preliminary cooling of the branch exhaust gas.

[0031] The pre-cooled airflow continues to flow through the hot side flow passage of the second heat exchanger 6, where it is subjected to secondary heat exchange with the low-temperature airflow from the turbine 4 exhaust, thereby achieving deep cooling. Subsequently, the low-temperature airflow enters the cavity 301 of the motor 3 through the cooling gas passage 7 to effectively cool the heat-sensitive components such as motor windings and bearings. The heat-exchanged airflow enters the turbine 4 to expand and do work, and is discharged at a reduced temperature and flows into the cold side flow passage of the second heat exchanger 6 to cool the hot side airflow of the second heat exchanger 6 as a cold source, thereby completing the cold energy recovery. Finally, the low-temperature exhaust gas is discharged into the heat shield 1, part of which is retained in the shield, and part of which is discharged through the exhaust port 102 to carry out the system heat.

[0032] ​Since the temperature of the gas discharged by the turbine 4 is lower than the temperature of ram air in the external high-Mach flight environment, the gas can create a relatively low-temperature microenvironment in the cover after being discharged into the cover, which not only helps to maintain the low-temperature operation state of the motor 3, bearings and other components, but also further improves the utilization efficiency of cold energy, so that the entire system realizes efficient and reliable self-cooling circulation under the condition of no external cold source.

[0033] On the basis of the above structure, the shell of the motor 3 is provided with a spiral air channel 302 in a sandwich structure, which is used for actively cooling the motor shell itself. The side of the cavity 301 is provided with a communication hole 3011, one end of the spiral air channel 302 communicates with the cavity 301 through the communication hole 3011, and the other end communicates with the airflow inlet of the turbine 4.

[0034] In operation, the cooling gas in the cavity 301 enters the spiral air channel 302 through the communication hole 3011 and flows along the spiral air channel 302 in a spiral path, and finally flows into the airflow inlet of the turbine 4.

[0035] The spiral air channel 302 as a sandwich flow channel around the shell of the motor 3 significantly prolongs the heat exchange path between the cooling gas and the shell, so that heat can be carried away more uniformly in the axial and circumferential directions, effectively avoiding the formation of hot spots in the local area of the motor shell due to poor heat dissipation. Therefore, not only the heat management capability of the motor 3 shell itself is improved, but also the cooling uniformity of the winding and internal components is enhanced, thereby significantly improving the operation safety and long-term stability of the motor 3 under high heat load conditions.

[0036] On the basis of the above structure, the compressor 2 is arranged at the front end of the shell of the motor 3, and the turbine 4 is arranged at the rear end of the shell of the motor 3, and the three are coaxially integrated to form a front-rear symmetrical coaxial rotor structure, which is beneficial to the compactness of the system and the efficient transmission of power.

[0037] The front end and the rear end of the shell of the motor 3 are provided with shaft holes 303, one end of the rotor of the motor 3 extends into the shell of the compressor 2 through the shaft hole 303 at the front end, and the other end extends into the shell of the turbine 4 through the shaft hole 303 at the rear end. Radial bearings 31 are installed in the two shaft holes 303, and the radial bearings 31 are arranged on the rotor of the motor 3 for supporting the high-speed rotation of the rotor and maintaining the coaxial stability of the rotor.

[0038] An axial sealing disc 32 is arranged in the shaft hole 303 at the front end, which is used to seal the fitting gap between the rotor of the motor 3 and the shaft hole 303, effectively preventing the leakage of high-temperature pressurized gas in the compressor 2 into the internal cavity 301 of the motor 3, and ensuring the thermal safety of the internal environment of the motor 3.

[0039] The radial bearing 31 retains a bearing play, on one hand, the cooling air flow enters the bearing interior, and the bearing raceway and cage are directly cooled, and the friction temperature rise is reduced. On the other hand, the play of the rear end radial bearing 31 is used as a guide channel of the cooling air flow, so that the cooling gas in the cavity 301 can flow into the turbine 4 smoothly through the play to participate in work. Thus, the structure realizes reliable support of the rotor and sealing of the front end, and at the same time, a cooling air flow path from the cavity 301 of the motor 3 to the impeller area in the interior of the turbine 4 shell through the play of the rear end bearing is constructed, the three functions of mechanical support, thermal sealing and air flow guide are highly integrated, and the compactness, cooling efficiency and operation reliability of the system are improved.

[0040] On the basis of the above structure, the impeller front end of the turbine 4 is coaxially provided with a thrust bearing 33, the thrust bearing 33 is sleeved on the outer periphery of the rotor of the motor 3, and the front end thereof abuts against the rear end of the shell of the motor 3, for bearing the axial thrust of the rotor assembly, and ensuring the stability of rotation.

[0041] The thrust bearing 33 retains a designed play in structure, the play is communicated with the rear end shaft hole 303, and cooperates with the bearing play of the rear end radial bearing 31 to jointly form a micro-scale cooling air flow channel from the cavity 301 of the motor 3 to the impeller area in the interior of the turbine 4 shell. The cooling gas sequentially passes through the play of the radial bearing 31 and the play of the thrust bearing 33 through the cavity 301, and flows into the turbine 4 stably, so as to realize effective cooling and air flow guide of the bearing area.

[0042] Thus, the radial bearing 31 and the thrust bearing 33 bear the functions of radial support and axial positioning of the rotor respectively, and the internal designed plays thereof jointly form the cooling air flow channel, and have the dual functions of mechanical bearing and air flow guide, so as to realize the integrated design of “bearing-flow guide”. The structure effectively cools the bearing area, and does not need to additionally set an independent cooling flow channel, so that the system layout is significantly simplified, the space utilization is improved, and the reliability of the cooling path and the integration of the overall structure are enhanced.

[0043] On the basis of the above structure, the shell of the turbine 4 is coaxially provided with an annular flow guide cavity 401 along the circumference of the impeller. The front end of the annular flow guide cavity 401 is provided with an air inlet, and the annular flow guide cavity 401 constitutes the air inlet of the turbine 4. Meanwhile, the inner ring wall of the annular flow guide cavity 401 is uniformly distributed with a plurality of flow guide holes 4011 along the circumference. After the cooling air flow enters the annular flow guide cavity 401, the cooling air flow is accelerated and uniformly injected to each blade inlet of the turbine 4 impeller through the flow guide holes 4011.

[0044] The structure rectifies the airflow entering the impeller area, improves the circumferential uniformity and flow stability of the intake air, effectively suppresses local vortex and flow separation, and reduces flow loss. Thus, the expansion work efficiency of the turbine 4 is improved, not only enhancing the ability of waste gas energy recovery in the cooling cycle, but also further optimizing the overall thermal management performance of the system, ensuring the efficient and stable operation of the electric compressor system under extreme conditions such as high Mach number flight.

[0045] The above structure forms a completely self-sustaining open cooling cycle, which does not rely on external cold sources to achieve efficient self-cooling of the motor 3 and bearings and recovery and utilization of turbine 4 exhaust cooling capacity.

[0046] The cooling method specifically includes the following steps: S1, ram air enters the cold side flow channel of the first heat exchanger 5 through the ram air inlet 101 on the heat shield 1, and then enters the compressor 2 for pressurization.

[0047] S2, part of the exhaust gas of the compressor 2 is introduced into the hot side flow channel of the first heat exchanger 5, and exchanges heat with the ram air in the cold side flow channel of the first heat exchanger 5 to preliminarily cool.

[0048] S3, the preliminarily cooled gas flow is introduced into the hot side flow channel of the second heat exchanger 6, and exchanges heat with the cold side gas flow from the turbine 4 exhaust to deeply cool.

[0049] S4, the deeply cooled gas flow is introduced into the cavity 301 inside the motor 3 through the cooling gas passage 7 to cool the components inside the motor 3.

[0050] S5, the cooled gas flow is guided into the turbine 4 to expand and work.

[0051] S6, the low-temperature gas flow discharged from the turbine 4 is introduced into the cold side flow channel of the second heat exchanger 6 to cool the gas flow in the hot side flow channel of the second heat exchanger 6, and then is discharged into the heat shield 1 and is discharged through the exhaust port 102.

[0052] In this method, the direction of the gas flow is as shown in Figure 3 The specific process is as follows: The ram air passes through the cold side flow channel of the first heat exchanger 5 (i.e. the compressor end radiator) to reach the compressor 2, and is discharged after being pressurized by the impeller of the compressor 2.

[0053] The pressurized exhaust gas is divided at the outlet flow path of the compressor 2: part of the exhaust gas is supplied to the downstream equipment through the main flow path 201, and the other part of the exhaust gas enters the hot side flow channel of the first heat exchanger 5 through the branch flow path 202, and exchanges heat with the ram air in the cold side flow channel to preliminarily cool.

[0054] After initial cooling, the airflow exits from the hot side channel of the first heat exchanger 5 and then enters the hot side channel of the second heat exchanger 6 (i.e., the turbine-end radiator in the figure), where it undergoes secondary heat exchange with the low-temperature exhaust gas from the turbine 4, completing deep cooling. The deeply cooled airflow then enters the internal cavity 301 of the motor 3 through the cooling air channel 7.

[0055] Inside the motor 3, the cooling airflow is further divided: one part of the airflow flows through the rotor, stator, and other components, then enters the annular guide cavity 401 through the spiral air passage 302, and is then accelerated by the guide hole 4011 and sprayed onto the impeller of the turbine 4. Another part of the airflow cools the radial bearing 31 and the thrust bearing 33 through the micro-scale cooling airflow channel, and then merges into the turbine 4 (impeller area). A small amount of airflow leaks into the heat shield 1 due to assembly gaps and other reasons.

[0056] Turbine 4 expands the incoming airflow to perform work, expelling low-temperature exhaust gas. This low-temperature exhaust gas flows in from the cold-side inlet of the second heat exchanger 6, cooling the airflow in the hot-side inlet of the second heat exchanger 6, thereby achieving heat recovery. Finally, the gas that has undergone heat recovery flows out from the cold-side outlet of the second heat exchanger 6, enters the interior of the heat shield 1, and is discharged through the exhaust port 102.

[0057] In the above method, the opening degree of control valve 8 is adjusted in a closed loop according to the motor temperature td or the bearing temperature tz to ensure that the system can achieve thermal safety operation while meeting the aerodynamic performance requirements.

[0058] like Figure 4 As shown, under specific operating conditions, the electric compressor system must meet the following operating constraints: the outlet flow rate is not lower than the set value mi, the pressure ratio is not lower than the set value PRi, the motor temperature td cannot exceed TS, and the bearing temperature tz must be maintained within the preset operating range [T1, T2] to ensure the stability of the bearing temperature and the reliability of the structure.

[0059] After the system is powered on, motor 3 starts to increase its speed. During the speed increase process, the outlet flow rate and pressure ratio of compressor 2 are monitored in real time. When the outlet flow rate and pressure ratio of compressor 2 meet the requirements, it is then determined whether the motor temperature td is greater than TS and whether the bearing temperature tz is between [T1, T2]. When the above conditions are met, the motor speed n is kept basically unchanged and the system enters steady-state operation.

[0060] When the motor temperature td exceeds the safety threshold TS, it indicates that motor 3 is at risk of overheating. At this time, the system automatically reduces the motor speed n to reduce heat generation and cause the motor temperature td to drop back to normal. TS Next, ensure the safety of electrical components.

[0061] When the bearing temperature tz is lower than the preset lower limit T1, it means that the cooling is excessive, which may cause freezing and blockage. At this time, the opening of the control valve 8 is reduced, the cooling gas flow is reduced, and the bearing temperature tz is raised to the normal working range.

[0062] When the bearing temperature tz is higher than the preset upper limit T2, the opening of the control valve 8 is increased, the cooling gas flow is increased, and the cooling of the bearing area is strengthened, so that the temperature is reduced until it falls within the range of [T1, T2].

[0063] The control strategy combines the aerodynamic performance constraints and the thermal management requirements, and realizes the safe, efficient and adaptive operation of the electric compressor system in the extreme thermal environment such as high Mach flight, by adjusting the opening of the control valve 8 and the coordinated control of the motor speed.

[0064] In order to realize intelligent regulation and control of the cooling process, the control valve 8 is arranged on the cooling gas passage 7 for dynamically adjusting the cooling gas flow into the cavity 301 of the motor 3. The shell and the internal key parts (such as windings, front and rear bearing areas) of the motor 3 are provided with temperature sensors for real-time monitoring of the operating temperature. Each temperature sensor and the control valve 8 are connected to the central control system (such as the aircraft central control console) of the aircraft through cables. After receiving the temperature signal, the central control system sends adjustment instructions to the control valve 8 according to the preset control logic, realizes closed-loop control of the cooling flow, and ensures that the motor 3 operates efficiently and stably within the safe temperature range.

[0065] The above only describes the preferred embodiments of the present application, and does not limit the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An electric compressor system, characterized in that: The system includes a heat shield (1), and also includes a compressor (2), a motor (3), a turbine (4), a first heat exchanger (5), and a second heat exchanger (6) fixed inside the heat shield (1), wherein, The impeller of the compressor (2), the rotor of the motor (3), and the impeller of the turbine (4) are coaxially connected to form a coaxial rotor assembly; The cold side flow channel inlet of the first heat exchanger (5) is connected to the ram air inlet (101) provided on the heat insulation cover (1), and the outlet is connected to the airflow inlet of the compressor (2); The inlet of the hot side flow channel of the first heat exchanger (5) is connected to the outlet flow channel of the compressor (2), and the outlet is connected to the inlet of the hot side flow channel of the second heat exchanger (6). The hot side flow channel outlet of the second heat exchanger (6) is connected to the internal cavity (301) of the motor (3) through the cooling gas channel (7), and the cavity (301) is connected to the airflow inlet of the turbine (4); The airflow outlet of the turbine (4) is connected to the cold side flow channel inlet of the second heat exchanger (6), the cold side flow channel outlet of the second heat exchanger (6) is connected to the interior of the heat insulation cover (1), and the heat insulation cover (1) is provided with an exhaust port (102).

2. The electric compressor system as described in claim 1, characterized in that: The outlet flow path of the compressor (2) includes a main flow path (201) and a branch flow path (202), wherein, The main flow path (201) extends out of the heat insulation cover (1) and is used to supply gas to downstream equipment; The branch path (202) is connected to the hot side flow channel of the first heat exchanger (5).

3. The electric compressor system as described in claim 1, characterized in that: Both the first heat exchanger (5) and the second heat exchanger (6) are cross-flow air-to-air heat exchangers.

4. The electric compressor system as described in claim 1, characterized in that: The motor (3) housing is provided with a spiral air passage (302), and the cavity (301) side is provided with a connecting hole (3011), wherein, One end of the spiral air passage (302) is connected to the cavity (301) via the connecting hole (3011), and the other end is connected to the airflow inlet of the turbine (4).

5. The electric compressor system as described in claim 1, characterized in that: The compressor (2) is located at the front end of the housing of the motor (3), and the turbine (4) is located at the rear end of the housing of the motor (3). The motor (3) has shaft holes (303) at both the front and rear ends of its housing. One end of the rotor of the motor (3) extends into the housing of the compressor (2) through the shaft hole (303) at the front end, and the other end extends into the housing of the turbine (4) through the shaft hole (303) at the rear end. Radial bearings (31) are installed in both of the shaft holes (303), and the radial bearings (31) are located on the rotor of the motor (3); An axial sealing disc (32) is provided in the shaft hole (303) at the front end to seal the fitting gap between the rotor of the motor (3) and the shaft hole (303); The radial bearing (31) has bearing clearance, and the airflow in the cavity (301) flows into the housing of the turbine (4) through the bearing clearance of the radial bearing (31) at the rear end.

6. The electric compressor system as described in claim 5, characterized in that: The impeller front end of the turbine (4) is coaxially provided with a thrust bearing (33), wherein, The thrust bearing (33) is sleeved on the outer periphery of the rotor of the motor (3), and its front end abuts against the rear end of the housing of the motor (3). The thrust bearing (33) has bearing clearance, and the rear shaft hole (303) is connected to the inside of the turbine (4) housing through the bearing clearance of the thrust bearing (33).

7. The electric compressor system as described in claim 1, characterized in that: An annular guide cavity (401) is coaxially arranged on the casing of the turbine (4) along the circumference of the impeller, wherein, The annular guide cavity (401) has an opening at its front end, forming the airflow inlet of the turbine (4); The inner ring of the annular guide cavity (401) is provided with a plurality of guide holes (4011) along the circumferential direction. The airflow in the annular guide cavity (401) is injected into the impeller of the turbine (4) through the guide holes (4011).

8. A cooling method for an electric compressor system, using the electric compressor system as described in any one of claims 1-7, characterized in that: Includes the following steps: S1. The ram air enters the cold side flow channel of the first heat exchanger (5) through the ram air inlet (101) on the heat insulation cover (1), and then enters the compressor (2) for pressurization; S2. Part of the exhaust gas from the compressor (2) is introduced into the hot side channel of the first heat exchanger (5) to exchange heat with the ram air in the cold side channel of the first heat exchanger (5) and thus achieve initial cooling. S3. The pre-cooled airflow is introduced into the hot side channel of the second heat exchanger (6) to exchange heat with the cold side airflow from the exhaust of the turbine (4) for deep cooling. S4. The deeply cooled airflow is introduced into the cavity (301) inside the motor (3) through the cooling air channel (7) to cool the components inside the motor (3); S5. Guide the cooled airflow into the turbine (4) to expand and do work; S6. The low-temperature airflow discharged from the turbine (4) is introduced into the cold side channel of the second heat exchanger (6) to cool the airflow in the hot side channel of the second heat exchanger (6), and then discharged into the heat shield (1) and discharged through the exhaust port (102).

9. A cooling method for an electric compressor system as described in claim 8, characterized in that: The cooling air passage (7) is equipped with a control valve (8) for regulating the flow rate of cooling air entering the motor (3).

10. A cooling method for an electric compressor system as described in claim 9, characterized in that: The opening degree of the control valve (8) is adjusted according to the motor temperature or bearing temperature: When the bearing temperature is below the preset lower limit, reduce the opening to reduce the cooling air flow and allow the bearing temperature to rise again. When the bearing temperature exceeds the preset upper limit, the opening is increased to increase the cooling air flow, thereby reducing the bearing temperature. When the motor temperature exceeds the safety threshold, reduce the speed of the motor (3) to bring the motor temperature back below the safety threshold.

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