A ring-distributed hybrid energy storage and in-flight wireless energy replenishment system

Abstract

This application relates to the field of wireless power transfer technology and discloses a ring-shaped distributed hybrid energy storage and in-flight wireless power replenishment system, including a ground-based transmitting base station and an airborne receiving terminal. The airborne receiving terminal includes multiple circumferentially distributed fan-shaped battery compartments, each integrating an antenna array, hybrid energy storage, and a control routing module. The control routing module adjusts the antenna input impedance according to the battery status: switching to a matched state to absorb microwave energy when charging is needed; and switching to a total reflection mismatch state when fully charged or in a faulty state, using the increased radar cross-section to reflect pilot signals for identification by the ground base station and to form an energy null trap. The hybrid energy storage module uses supercapacitors to smooth power pulsations in time-division duplex mode. The system employs a microcapsule phase change fluid loop for thermal management. This invention achieves on-demand energy distribution without the need for an independent communication link, improving the stability of energy transfer and the system's thermal safety.

Description

Technical Field

[0001] This invention relates to the field of wireless power transmission technology, specifically to a ring-shaped distributed hybrid energy storage and in-flight wireless power replenishment system. Background Technology

[0002] High-altitude long-endurance aircraft have significant applications in fields such as communication relay, Earth observation, and environmental monitoring. However, limited by the energy density of existing chemical batteries and the diurnal cycling limitations of solar cells, achieving sustained endurance for these aircraft has become a key bottleneck restricting the development of this technology. Microwave wireless power transfer technology, which transmits microwave beams from a high-power ground-based base station to an airborne receiving terminal, provides continuous power replenishment to the aircraft and is an effective way to address range anxiety.

[0003] However, in practical applications, in-flight wireless power transfer technology faces multiple technical challenges. Existing microwave transmission systems typically treat the receiver as a single load node. However, when the aircraft uses a ring or distributed receiver array, due to changes in fuselage attitude and differences in battery pack consistency, receiver modules in different locations often operate at different states of charge. Traditional control methods rely on independent communication links to upload battery status data, which the ground base station then uses to adjust beam pointing. This approach not only increases the bandwidth pressure and latency of the communication system but also makes it difficult to achieve microsecond-level beam response in high-speed dynamic scenarios, easily leading to beam misalignment and projecting high-power energy onto already fully charged areas, posing a risk of battery overcharging.

[0004] Furthermore, to achieve flexible beam scanning and target tracking, modern microwave transmission systems often employ phased array architectures or time-division duplex operation, resulting in a significant pulse characteristic in the energy arriving at the airborne receiver. Existing airborne power management architectures mostly use rectifier circuits to directly charge the chemical batteries, lacking effective power smoothing mechanisms. High-frequency power pulsations generate substantial voltage ripple on the DC bus, leading to side reactions within the battery, accelerating battery aging, and reducing the cycle life of the energy storage system.

[0005] Meanwhile, the high-altitude environment is characterized by low air pressure and thin air, resulting in extremely low convective heat dissipation efficiency. Microwave rectifier devices generate heat loss under high power input. Without efficient thermal management measures, heat can easily accumulate locally in the rectifier array, causing the diode junction temperature to rise. This not only reduces rectification efficiency but can also lead to thermal breakdown of the device in severe cases, threatening the operational safety of the aircraft. Existing heat dissipation solutions are mostly designed for ground or low-altitude dense atmospheric environments, making it difficult to meet the dual requirements of lightweight design and efficient heat dissipation for high-altitude aircraft. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a ring-shaped distributed hybrid energy storage and in-flight wireless energy replenishment system. This system solves the problem that existing long-endurance aircraft are limited by battery energy density, making it difficult to break through the bottleneck of endurance. Furthermore, traditional wireless energy transmission technologies suffer from problems such as beam alignment difficulties, low energy transmission efficiency, thermal effects caused by high-power microwaves, and large power supply voltage ripple in dynamic transmission scenarios.

[0007] To achieve the above objectives, this invention provides the following technical solution: a ring-shaped distributed hybrid energy storage and in-flight wireless energy replenishment system, comprising a ground-based transmitting base station for establishing a microwave link and an airborne receiving terminal. The ground-based transmitting base station is equipped with a millimeter-wave phased array for transmitting microwave energy beams and performing beam scanning. The airborne receiving terminal is integrated into the aircraft and includes multiple physically isolated sector-shaped battery compartments distributed circumferentially. Each sector-shaped battery compartment integrates an antenna array module, a hybrid energy storage module, and a control routing module. The antenna array module is laid on the outer skin surface of the sector-shaped battery compartment, used to receive microwave energy beams and convert them into DC power, and has adjustable input impedance. The hybrid energy storage module is electrically connected to the antenna array module and includes a lithium-sulfur battery pack and a supercapacitor pack. The control routing module is electrically connected to each sector-shaped battery compartment, used to collect battery status and generate a global state vector, control the antenna array module to switch between impedance matching and impedance mismatch states, and adjust the absorption or reflection characteristics of the sector-shaped battery compartments for microwave energy beams.

[0008] Furthermore, the ground-based transmission base station also includes a beam controller for performing channel state awareness and adaptive transmission. During the pilot sounding time slot, the beam controller calculates the spatial orientation and impedance state of each sector electronic compartment based on the amplitude differences of the echo signals received by the millimeter-wave phased array. During the power transmission time slot, the beam controller generates a beamforming weight vector based on the calculation results, controlling the millimeter-wave phased array to ensure that the high-energy region of the transmitted beam covers the impedance-matched region and forms an energy null in the impedance-mismatched region.

[0009] Furthermore, the control routing module executes impedance control logic based on state feedback. When the state of charge of the lithium-sulfur battery pack in the sector-shaped battery compartment is below a preset threshold and the temperature is normal, the control routing module controls the corresponding antenna array module to switch to a conjugate-matched state, making the voltage reflection coefficient approach zero. When the state of charge of the lithium-sulfur battery pack in the sector-shaped battery compartment is above the preset threshold or a fault occurs, the control routing module controls the corresponding antenna array module to switch to a total reflection mismatch state, making the voltage reflection coefficient approach one. The antenna array module in the total reflection mismatch state increases the radar cross-section through a high reflection coefficient, using the reflected signal as a passive state identifier for the ground transmitting base station to identify the current area as a non-charging target area.

[0010] Furthermore, the hybrid energy storage module employs an electrical topology designed for pulse power smoothing. The supercapacitor bank is directly connected in parallel to the internal DC bus at the antenna array module output for voltage clamping. The lithium-sulfur battery pack is connected to the internal DC bus via a bidirectional DC-DC converter that responds to low-frequency power commands according to a frequency decoupling strategy. The ground-based transmitting base station and the airborne receiving terminal are configured for energy exchange in time-division duplex mode. In this mode, during the arrival of microwave pulses in the power transmission time slot, the supercapacitor bank utilizes its low impedance characteristics to absorb instantaneous power peaks, limiting the voltage ripple of the internal DC bus within a preset range; during pilot detection time slots or beam scanning gaps, the supercapacitor bank releases charge to the internal DC bus to maintain power continuity.

[0011] Furthermore, the antenna array module employs a multilayer dielectric substrate and microstrip patch antenna elements integrated thereon. Each microstrip patch antenna element is connected in series with the rectifier circuit via an impedance modulation circuit. The impedance modulation circuit includes a PIN diode, and the control routing module modulates the input impedance by adjusting the bias voltage applied to the PIN diode to change the equivalent reactance of the RF path.

[0012] Furthermore, the system also includes a thermal management module for dissipating the heat generated by the high-power microwave conversion. The thermal management module comprises a fluid loop running through the fan-shaped electronic compartment and a micro-circulation pump. The fluid loop is filled with microcapsule phase change fluid containing phase change capsule particles suspended in a base fluid, with the phase change temperature of the capsule particles set between 40°C and 50°C. The internal components of the fan-shaped electronic compartment have a stacked heat conduction structure, consisting of an antenna array module, a microchannel liquid cooling plate, and a hybrid energy storage module, from the outside in. The microchannel liquid cooling plate is connected to the fluid loop and is used to transfer the heat generated by the antenna array module to the microcapsule phase change fluid. The non-transparent skin surface of the fan-shaped electronic compartment is provided with a radiative heat dissipation surface to radiate the heat from the microcapsule phase change fluid flowing through it to the external environment.

[0013] Furthermore, the ground-based transmitting base station and the airborne receiving terminal are configured to operate collaboratively based on a superframe structure. Each superframe contains a pilot detection time slot and a power transmission time slot. Before the power transmission time slot begins, the control routing module pre-triggers the sector-shaped battery compartments with charging needs to enter impedance matching mode, and simultaneously instructs the hybrid energy storage module to enter energy absorption mode to avoid the impact of hardware response delay on energy reception efficiency.

[0014] This invention provides a ring-shaped distributed hybrid energy storage and in-flight wireless power replenishment system. It offers the following advantages:

[0015] 1. This invention establishes a passive feedback loop based on physical layer radio frequency characteristics through the impedance modulation mechanism of the antenna array. When the fan-shaped battery compartment does not need to be charged or malfunctions, the control system switches the antenna to a total reflection mismatch state. By using the increased radar cross section to reflect the pilot signal, the ground transmitting base station can automatically identify and avoid non-target areas at the physical layer. By establishing an additional two-way communication link, energy can be delivered accurately on demand, reducing system communication overhead and preventing overcharging and thermal damage to fully charged batteries or faulty nodes from the source.

[0016] 2. This invention adopts a hybrid energy storage architecture that combines lithium-sulfur batteries and supercapacitors, effectively solving the problems of intermittency and pulsation in microwave energy transmission under time-division duplex mode. It utilizes the power density advantage of supercapacitors to absorb the instantaneous peak energy of the power transmission time slot and fill the power supply gap in the pilot detection time slot, limiting the voltage ripple of the internal DC bus to a safe range. At the same time, with the help of a frequency decoupling control strategy, the lithium-sulfur battery only responds to the smoothed low-frequency power command, avoiding the impact of large ripple current on the battery plates, thereby extending the service life of the high-energy-density battery.

[0017] 3. This invention establishes a closed-loop thermal management system based on microcapsule phase change fluid, which adapts to the heat dissipation requirements in the thin atmosphere at high altitudes. Through a stacked structure, the heat generated by the antenna array is quickly transferred to the microchannel liquid cooling plate. By utilizing the latent heat absorption characteristics of the microcapsule phase change process, the rectifier device is maintained to operate within a constant temperature range, avoiding the efficiency reduction or thermal breakdown of the rectifier diode due to temperature rise. In addition, the radiative heat dissipation surface of the non-transparent skin is used to directly dissipate waste heat to the external cold space, ensuring the thermal stability of the system under continuous high-power microwave irradiation. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall architecture of the present invention;

[0019] Figure 2 This is a schematic diagram of the millimeter-wave phased array architecture of the ground transmission base station of the present invention;

[0020] Figure 3 This is a simulation diagram of the sector impedance state and energy reception distribution of the present invention;

[0021] Figure 4 This is a comparison diagram of DC bus voltage ripple suppression in the hybrid energy storage system of the present invention.

[0022] Figure 5 This is a comparison chart of the temperature rise curves of the thermal management system of the present invention.

[0023] Among them, 100 is the ground transmission base station; 110 is the millimeter-wave phased array; 120 is the beam controller; 200 is the airborne receiving terminal; 210 is the fan-shaped battery compartment; 300 is the hybrid energy storage module; 310 is the lithium-sulfur battery pack; 320 is the supercapacitor pack; 400 is the antenna array module; 500 is the thermal management module; and 600 is the control routing module. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Please see the appendix Figure 1 This invention provides a ring-shaped distributed hybrid energy storage and in-flight wireless power replenishment system, comprising:

[0026] Ground-based transmission base station 100 is installed on a fixed facility on the ground surface and is used to transmit millimeter-wave microwave energy beams. It has beam scanning, channel detection and adaptive beamforming functions.

[0027] The airborne receiving terminal 200 is integrated into the aircraft's ring structure and is used to receive microwave energy and store and distribute electrical energy. It includes multiple physically isolated fan-shaped electrical compartments 210.

[0028] The hybrid energy storage module 300, integrated inside the fan-shaped battery compartment 210, includes a lithium-sulfur battery pack 310 and a supercapacitor pack 320, for providing basic energy storage and instantaneous power throughput.

[0029] Antenna array module 400, laid on the outer skin surface of the aircraft corresponding to the fan-shaped electronic compartment 210, includes impedance modulation circuitry, used to convert space microwave energy into DC power and adjust port impedance.

[0030] The thermal management module 500 is a closed fluid pipeline that runs through the fan-shaped electrical compartment 210, including a circulation pump and a radiant heat dissipation surface, used to maintain the operating temperature of the components.

[0031] The control routing module 600 is electrically connected to the fan-shaped battery compartment 210 and the antenna array module 400, and is used to collect status data, generate charging strategies and control impedance modulation.

[0032] A radio electromagnetic wave link is established between the ground transmitting base station 100 and the airborne receiving terminal 200 for contactless energy exchange. Twelve fan-shaped electrical compartments 210 are evenly distributed along the circumference of the aircraft within the airborne receiving terminal 200. A flame-retardant and heat-insulating layer is installed between adjacent fan-shaped electrical compartments 210.

[0033] The ground-based base station 100 includes a millimeter-wave phased array 110 and a beam controller 120. The millimeter-wave phased array 110 consists of a two-dimensional radio frequency transceiver array. The beam controller 120 is connected to the millimeter-wave phased array 110 and performs channel estimation algorithms and beam weight calculations.

[0034] The system operates collaboratively based on a time-division duplex mechanism, cyclically switching between pilot detection time slots and power transmission time slots. The control routing module 600 periodically collects the state of charge, temperature, and health data of the lithium-sulfur battery packs 310 within the sector-shaped battery compartment 210, generating a global state vector containing the charging needs of each sector. Based on this vector, the control routing module 600 adjusts the input impedance of the corresponding antenna array module 400: for sector-shaped battery compartments 210 with charging needs and normal temperature, its input impedance is adjusted to a conjugate-matched state; for sector-shaped battery compartments 210 without charging needs or with malfunctions, its input impedance is adjusted to a total reflection mismatched state.

[0035] Ground-based base station 100 transmits a low-power omnidirectional sounding signal during the pilot sounding time slot. Millimeter-wave phased array 110 receives the echo signal from airborne receiving terminal 200. Because antenna array modules 400 in different sectors exhibit different reflection coefficients, the echo signal carries information about the position and impedance status of each sector. Beam controller 120 processes the echo signal, inverts the spatial distribution and energy reception requirements of each sector's electronic compartment 210, calculates the beamforming weight vector, ensuring the transmitted beam's energy focus covers the impedance matching region and forms an energy null in the impedance mismatch region. Subsequently, ground-based base station 100 loads the beamforming weight vector during the power transmission time slot and transmits a high-power microwave energy beam. During this period, airborne receiving terminal 200 locks all antenna array modules 400 to a matched state, converts the microwave energy into pulsating DC power, smooths it via hybrid energy storage module 300, and stores it in lithium-sulfur battery pack 310. Simultaneously, thermal management module 500 continuously removes system heat.

[0036] See attached document Figure 2 The core component of the ground-based base station 100 is a millimeter-wave phased array 110. The millimeter-wave phased array 110 adopts an active electronically scanned array (AESA) architecture, including multiple radio frequency antenna elements distributed in a two-dimensional plane and their corresponding radio frequency transceiver components. In this embodiment, the operating frequency band of the millimeter-wave phased array 110 is selected as the Ka band (e.g., 28 GHz) or the W band (e.g., 94 GHz) to balance the low-loss characteristics of the atmospheric transmission window with the directional accuracy of the high-gain beam. Each radio frequency antenna element contains an independent radiating patch or waveguide slot, and their physical spacing is set to half the operating wavelength to avoid grating lobe interference and achieve wide-angle scanning capability.

[0037] The radio frequency (RF) transceiver assembly is the key hardware for achieving flexible beam control. Each RF transceiver assembly integrates a low-noise amplifier (LNA), a high-power amplifier (HPA), a digitally controlled phase shifter, and a digitally controlled attenuator. The LNA is used to pre-amplify the weak echo signal in receive mode to improve the signal-to-noise ratio; the HPA is used to amplify the microwave signal to a predetermined power level in transmit mode. The digitally controlled phase shifter and digitally controlled attenuator are controlled by digital commands from the beam controller 120 to adjust the phase and amplitude of the RF signal passing through the assembly, respectively. By precisely controlling the phase distribution of each RF antenna element in the two-dimensional array, the millimeter-wave phased array 110 can change the equiphase surface of the synthesized beam without mechanical rotation, thereby achieving rapid electronic scanning of the transmit or receive beam in space.

[0038] To enable the reuse of energy transmission and target detection functions, the hardware architecture of the millimeter-wave phased array 110 supports rapid state switching in time division duplex (TDD) mode.

[0039] Specifically, during the pilot detection time slot, the beam controller 120 issues an omnidirectional detection command to all RF transceiver components. At this time, the phase values ​​of each digitally controlled phase shifter are set to a randomly distributed or specified wide-beam phase codebook, resulting in a wide-coverage quasi-omnidirectional radiation pattern in the synthesized beam. Simultaneously, the high-power amplifier is in low-gain or bypass mode, and the transmit power is limited to a safe level in the milliwatt range. Subsequently, the system quickly switches to receive mode, using a low-noise amplifier to receive the echo signal from the airborne receiving terminal 200.

[0040] Subsequently, upon receiving the echo signal, the beam controller 120 extracts the spatial spectrum information and amplitude characteristics of the echo signal by executing a digital beamforming (DBF) algorithm or analog beamforming network processing. For a multi-channel receiving architecture, the beam controller 120 uses the phase difference of the received signals from each channel to estimate the signal's angle of arrival using a conventional MUSIC algorithm or ESPRIT algorithm, thereby determining the spatial orientation of the airborne sector-shaped electronic bay 210. Simultaneously, the beam controller 120 detects the amplitude intensity of the echo signal, identifying impedance mismatch regions exhibiting high reflection characteristics and impedance matching regions exhibiting low reflection characteristics. The specific beamforming algorithm and signal detection principle can be implemented using well-known techniques by those skilled in the art, and will not be elaborated upon here.

[0041] Upon entering the power transmission time slot, the beam controller 120 calculates the optimal beamforming weight vector based on the inverted target position and impedance state. The weight vector contains the optimal amplitude and phase configuration data for each array element. After calculation, the beam controller 120 loads the weight vector in parallel into the registers of all RF transceiver components.

[0042] Next, each RF transceiver component adjusts the phase delay of its internal numerically controlled phase shifter and the attenuation of its numerically controlled attenuator according to the loaded weight data. Simultaneously, the high-power amplifier is activated to either the saturation operating region or the high-efficiency linear region. At this point, the electromagnetic waves synthesized by the array undergo constructive interference in space, forming a high-gain narrow beam pointing towards the fan-shaped electronic compartment 210. The energy density of this narrow beam reaches its peak in the target region, while in non-target regions or impedance mismatch regions, phase cancellation forms an energy null point to suppress sidelobe leakage.

[0043] The ground-based transmission base station adopts a time-division duplex mechanism, which divides a single working cycle into pilot detection time slots and power transmission time slots. Through the logical scheduling of the beam controller, it cycles between radar detection mode and power transmission mode.

[0044] First, during the pilot detection time slot, the beam controller directs the millimeter-wave phased array to operate in low-power detection mode. The beam controller generates a set of orthogonal pilot sequences or linear frequency-modulated continuous wave signals, which are radiated into space in an omnidirectional or wide-beam configuration via the RF transceiver components. At this time, the transmit power is limited to a milliwatt-level safety threshold to prevent excessively high induced voltages from occurring if the airborne impedance is not locked.

[0045] After transmitting the detection signal, the ground-based base station switches to receiving mode to collect the echo signal from the airborne receiving terminal. Because different sectors of the airborne receiving terminal adjust the input impedance of their antenna ports according to their own charging needs, the echo signal carries the electromagnetic scattering characteristics of the corresponding sector. Specifically, sectors in a charging demand state exhibit low reflection characteristics (i.e., smaller echo amplitude) due to impedance matching, while sectors in a rejection state exhibit high reflection characteristics (i.e., larger echo amplitude) due to impedance mismatch.

[0046] Next, the beam controller performs channel estimation and state calculation on the received echo signals. The beam controller uses spatial spectrum estimation techniques to determine the angle of arrival and spatial azimuth of all sectors, and identifies the state of each sector based on the amplitude differences of the echo signals. The beam controller identifies azimuths exhibiting high reflectivity as non-target areas, and azimuths exhibiting low reflectivity or only structural scattering as target areas. Based on the identified spatial angles, the beam controller reconstructs the spatial channel state information corresponding to each sector.

[0047] Based on the channel state information matrix and node classification results, the beam controller executes an adaptive beamforming algorithm to calculate the optimal transmit weight vector for the power transmission time slot. This calculation process is modeled as a constrained convex optimization problem, the objective of which is to maximize the received power pointing towards the target node while satisfying the power leakage constraints at non-target nodes and the total transmit power constraint of the base station. The mathematical expression of this optimization problem is as follows:

[0048] ;

[0049] ;

[0050] ;

[0051] in, This represents the beamforming weight vector to be solved, which contains the complex weights of each element in the millimeter-wave phased array; This represents the set of target nodes identified as having a charging need. This represents the set of non-target nodes identified as not requiring charging or experiencing malfunctions. Indicates the ground transmission base station to the number The downlink spatial channel vector of each target node (determined by the angle of arrival and array manifold). Indicates the ground transmission base station to the number Downlink spatial channel vectors of non-target nodes; This represents the conjugate transpose operation; This represents the maximum allowable leakage power threshold for non-target nodes, which is set to a minimum value to form a null trap; This indicates the maximum transmission power of the ground-based base station.

[0052] Then, the beam controller uses a semidefinite relaxation algorithm or a zero-forcing precoding algorithm to solve the above optimization problem and obtain the optimal weight vector.

[0053] Finally, upon entering the power transmission time slot, the beam controller loads the calculated optimal weight vector into each phase shifter and attenuator of the millimeter-wave phased array and activates the high-power amplifier. At this point, the electromagnetic waves radiated by the millimeter-wave phased array superimpose in space to form a shaped beam. The high-energy region of the main lobe of this beam precisely covers the azimuth of the target node set, while forming deep nulls in the azimuth of non-target node sets, thereby achieving on-demand energy distribution and interference suppression at the physical layer.

[0054] The annular equipment bay constitutes the physical body of the airborne receiving terminal, and its design follows the integrated principle of aerodynamic stealth and electromagnetic compatibility.

[0055] The annular equipment bay, in its macroscopic geometry, presents itself as a closed ring or an annular streamline structure attached to the edge of the aircraft fuselage. This structure is conformally designed to the aerodynamic shape of the aircraft, maintaining the streamlined continuity of the aircraft surface to minimize aerodynamic drag. The outer skin of the annular equipment bay is made of a low-dielectric-constant, low-dielectric-loss transmissive composite material, such as quartz fiber-reinforced resin matrix composites, ensuring that microwave energy can penetrate the skin with low loss to reach the internal antenna array.

[0056] In terms of internal topology, the annular equipment compartment is physically divided circumferentially by several rigid partitions distributed radially. In this embodiment, there are 12 rigid partitions, which uniformly divide the annular space into 12 independent sector-shaped electrical compartments 210. The rigid partitions are made of high-temperature resistant, high-specific-strength materials, such as titanium alloys or carbon fiber reinforced polyether ether ketone (PEEK) composite materials, and are attached with aerogel insulation felt or ceramic fiber boards. This structural configuration achieves dual isolation between adjacent sector-shaped electrical compartments 210: firstly, mechanical isolation, preventing battery expansion or mechanical damage in one compartment from affecting adjacent compartments; secondly, thermal isolation, whereby when a battery thermal runaway occurs in one sector, the rigid partitions can block the lateral spread of heat to adjacent sectors, confining the fault to a single physical partition.

[0057] For the longitudinal section of a single sector-shaped battery compartment 210, its internal components adopt a stacked integrated architecture, including, from the outside in, an energy harvesting layer, a thermal management structure layer, and an energy storage layer. The energy harvesting layer is closely attached to the inner side of the outer wave-transparent skin and houses the impedance adaptive rectifier antenna array 400. The thermal management structure layer is located in the middle and consists of a microchannel liquid cooling plate. This liquid cooling plate serves as both the heat exchange interface of the heat sink and a mounting substrate, providing mechanical support for the inner and outer components. The energy storage layer is located on the innermost side and contains a lithium-sulfur battery pack 310 and a supercapacitor module 320. Both the energy harvesting layer and the energy storage layer are pressed onto the opposite surfaces of the microchannel liquid cooling plate using a high thermal conductivity interface material, forming a stacked double-sided heat exchange structure to ensure efficient heat dissipation on both sides.

[0058] Furthermore, each sector-shaped electrical compartment 210, as an independent modular unit, is fixed to the main load-bearing frame of the aircraft via standardized mechanical and electrical interfaces. The DC output busbar of each sector-shaped electrical compartment 210 is connected in series with an independent high-voltage solid-state circuit breaker or mechanical contactor, and converges to the central power management center of the aircraft via a high-voltage busbar. Communication lines are connected to the control routing module 600 via fiber optic cables or shielded twisted-pair cables. This modular layout allows the control system to control the corresponding circuit breaker to physically disconnect the connection of that sector in the event of an irreversible failure in a sector-shaped electrical compartment 210, without affecting the normal operation of the remaining 11 sectors or the overall aerodynamic balance of the aircraft.

[0059] The airborne receiving terminal adopts a hybrid topology architecture of distributed microgrid and centralized bus in terms of electrical connection. Each sector electrical compartment 210 is constructed as an independent DC microgrid node in electrical logic.

[0060] Within the internal electrical circuitry of a single sector-shaped electrical compartment 210, the DC output of the impedance-adaptive rectifier antenna array 400 is connected to the input of a primary filter circuit. The output of the primary filter circuit is connected to the internal DC bus. The supercapacitor module 320 is directly connected across this internal DC bus, forming a parallel connection with the output circuit of the impedance-adaptive rectifier antenna array 400. This parallel topology allows the supercapacitor module 320 to directly clamp voltage fluctuations on the internal DC bus and maintain bus voltage stability through discharge during microwave power transmission intervals.

[0061] Meanwhile, the lithium-sulfur battery pack 310 is connected to the internal DC bus via a bidirectional DC-DC converter. The bidirectional DC-DC converter integrates power semiconductor switching devices and energy storage inductors for voltage conversion and power flow control. When receiving high-power microwaves, the bidirectional DC-DC converter operates in buck mode, converting the high-voltage energy on the internal DC bus into a low-voltage, high-current suitable for the charging characteristics of the lithium-sulfur battery pack 310. When the aircraft's main load experiences peak power demand, the bidirectional DC-DC converter operates in boost mode, assisting the supercapacitor module 320 in outputting power. Simultaneously, the bidirectional DC-DC converter employs a voltage loop control strategy, adjusting the charging and discharging current of the lithium-sulfur battery pack to dynamically maintain the voltage of the internal DC bus at a preset unified reference voltage value, providing a voltage reference for subsequent multi-module parallel operation.

[0062] The power balance inside the sector-shaped electrical compartment 210 follows Kirchhoff's current law and the law of conservation of energy. (Definition of the first...) Each fan-shaped electrical compartment is at a constant time The node power balance equations are as follows:

[0063] ;

[0064] in, This represents the instantaneous power injected into the internal DC bus by the rectifier antenna array. This indicates the power absorbed (positive for charging) or released (negative for discharging) by the supercapacitor module; This indicates the power flowing to the lithium-sulfur battery pack via the bidirectional DC-DC converter; This indicates the load power output of this sector to the external airborne main high-voltage bus; This indicates the power loss during circuit conversion.

[0065] In terms of global electrical integration, the outputs of the 12 sector-shaped electrical bays 210 are connected in parallel to the aircraft's ring-shaped main high-voltage bus via high-voltage contactors or solid-state circuit breakers. The ring-shaped main high-voltage bus supplies power to the aircraft's electric propulsion system and avionics system. To suppress circulating currents in the parallel system, the output control of each sector-shaped electrical bay 210 adopts a droop control strategy, that is, fine-tuning the voltage setpoint of the internal DC bus according to the magnitude of the output current, thereby achieving automatic power distribution among the sectors. Each connection point between the sector-shaped electrical bay 210 and the ring-shaped main high-voltage bus is equipped with a current sensor and a fuse protection device. When the control routing module 600 detects an internal short circuit or voltage abnormality in a sector-shaped electrical bay 210, it controls the corresponding high-voltage contactor to disconnect, physically disconnecting it from the ring-shaped main high-voltage bus.

[0066] Finally, regarding the communication and control topology, the local controllers within each sector-shaped electrical compartment 210 are connected to the control routing module 600 via a fiber optic communication network. Fiber optic media was chosen to provide complete electromagnetic interference (EMI) immunity in strong microwave radiation environments, ensuring that the bit error rate of voltage sampling data, temperature data, and impedance control command transmission meets aerospace-grade safety standards.

[0067] The impedance adaptive rectifier antenna array 400 is manufactured using multilayer microwave integrated circuit technology. Its physical form is designed as a flexible conformal structure to closely fit the external aerodynamic surface of the aircraft's annular equipment bay.

[0068] The impedance-adaptive rectifier antenna array 400 is based on a multilayer dielectric substrate. This substrate is composed of a low-dielectric-constant, low-loss-tangential RF laminate, such as a liquid crystal polymer (LCP) or polytetrafluoroethylene (PTFE) ceramic composite material. Vertically, the substrate is divided into a radiating layer, a circuit layer, and a ground shielding layer. The radiating layer is located on the outermost side, directly facing free space; the circuit layer is located in the middle, encapsulating active devices; and the ground shielding layer is located on the innermost side, used to isolate RF signals from interference with internal electronic equipment.

[0069] Two-dimensional periodically distributed microstrip patch antenna elements are fabricated on the surface of the radiating layer using photolithography and etching processes. These microstrip patch antenna elements are designed for circular polarization reception, specifically achieved by employing chamfered square patches or orthogonal dual-feed structures, enabling the receiving antenna to respond to incident microwaves in any polarization direction. The physical spacing between each microstrip patch antenna element is set to be less than the operating wavelength to suppress grating lobe effects and improve the effective aperture efficiency of the array.

[0070] Each microstrip patch antenna element is vertically interconnected to the intermediate circuit layer via metallized vias. Within the circuit layer, each antenna element is configured with an independent rectifier circuit. The core component of the rectifier circuit is a high-frequency rectifier diode, specifically a gallium arsenide (GaAs) or silicon carbide (SiC) Schottky barrier diode. The rectifier topology employs a single-transistor parallel rectifier circuit or a voltage doubler rectifier circuit.

[0071] An input matching network and an impedance modulation component are integrated in the front-end input path of the rectifier diode. The impedance modulation component physically manifests as a variable reactance element or an RF switching element, such as a PIN diode or a MEMS switch. This impedance modulation component is designed as a tunable branch of the input matching network or directly connected in series at the antenna feed point. One end of this component is connected to the RF transmission line, and the other end is connected to the drive interface of the control routing module 600 via a bias circuit. By changing the bias voltage of the PIN diode, the equivalent impedance value on the RF path can be physically changed, thereby switching the RF characteristics of the antenna port between conjugate matching and total reflection mismatch states.

[0072] An on-chip microstrip low-pass filter is arranged on the output path of the rectifier diode. The microstrip low-pass filter is composed of fan-shaped short-circuited stubs or open-circuited short lines, and its cutoff frequency is set slightly higher than the DC component to block the fundamental frequency and the high-order harmonic frequencies generated by rectification. The DC power after preliminary filtering is collected through the bus network and passes through the insulating holes on the grounding shield layer, and is finally transmitted to the board-level filter circuit and hybrid energy storage module 300 inside the fan-shaped power compartment 210.

[0073] In addition, to address the heat dissipation issue under high-power microwave irradiation, a high thermal conductivity heat dissipation via array is uniformly distributed in the multilayer dielectric substrate. The heat dissipation vias penetrate the entire thickness of the substrate, directly conducting the Joule heat generated by the Schottky diodes and impedance modulation components to the bottom metal substrate, and further thermally coupling to the thermal management module 500 inside the fan-shaped electrical compartment 210.

[0074] Impedance adaptive modulation mechanism is the core technology for airborne receiving terminals to achieve on-demand energy capture and physical layer state feedback. It controls the absorption rate and reflection coefficient of incident microwaves by dynamically adjusting the RF input impedance of the rectifier antenna port.

[0075] The impedance adaptive modulation circuit is embedded between the microstrip patch antenna element and the rectifier circuit. The PIN diode, as the core control element, exhibits distinctly different RF impedance characteristics depending on its bias current state. When a forward bias current is applied, the PIN diode is equivalent to a low-resistance resistor (conduction state); when a reverse bias voltage is applied, the PIN diode is equivalent to a small-capacitance capacitor (cutoff state).

[0076] When the battery pack inside the fan-shaped battery compartment is undercharged and the temperature is within a safe range, the local controller outputs an energy harvesting command. At this time, the impedance adaptive modulation circuit enters a conjugate matching state. By adjusting the duty cycle of the PIN diodes or the bias voltage of the varactor diodes in the matching network, the input impedance seen from the antenna port is adjusted. With the source impedance of the antenna itself A conjugate matching relationship is formed. At this point, the reflection coefficient of the entire system approaches zero, and the radio frequency energy passes through the interface to the maximum extent and enters the rectifier circuit, where it is converted into DC electrical energy for storage.

[0077] Conversely, when the battery pack within the sector-shaped battery compartment is fully charged, malfunctions, or the temperature exceeds a safety threshold, the local controller outputs an energy rejection command. At this time, the impedance adaptive modulation circuit switches to a total reflection mismatch state. The control circuit adjusts the input impedance by changing the bias conditions. The modulation is set to pure reactive properties (i.e., the real resistance approaches zero, and the imaginary reactance is at its maximum or minimum, corresponding to an open circuit or short circuit). In this state, microwaves incident on the antenna surface cannot enter subsequent circuits but are instead radiated back into free space by the antenna structure.

[0078] The effects of the impedance modulation process described above on energy transfer efficiency and scattering characteristics can be assessed through the voltage reflection coefficient. A quantitative description is provided. The characteristic impedance of the antenna is defined as... The modulated input impedance is The voltage reflection coefficient is calculated as follows:

[0079] ;

[0080] Based on this reflection coefficient, the load power entering the rectifier circuit With incident power The relationship between them follows the following transport equation:

[0081] ;

[0082] in, This represents the RF-DC conversion efficiency of the rectifier circuit. Under conjugate matching conditions, , making Reaching its maximum value; under total internal reflection mismatch, For a purely imaginary number, | This not only protects a fully charged battery from overcharging, but also This results in an increase in the antenna's cross-section (RCS), generating a high-intensity, directional reflected echo. This echo, acting as a passive physical layer beacon, is captured by the probe beam of the ground-based base station to identify the sector's non-recharging status.

[0083] Furthermore, to prevent frequent impedance oscillations when the battery voltage approaches the full charge threshold, a Schmitt trigger or hysteresis comparator algorithm is introduced into the impedance control logic. Specifically, the system sets two voltage thresholds: the charging cut-off voltage... and restore charging voltage Only when the battery voltage The impedance only switches to a mismatch state when the battery voltage is depleted. Only when the impedance returns to a matched state will it be restored.

[0084] In order to convert the pulsating DC power output from the rectifier antenna into a clean and stable DC power supply, and to cope with the transient energy impact that occurs in high-power microwave transmission, the airborne receiver terminal has set up a multi-stage filtering and buffering architecture between the rectifier array and the chemical cell.

[0085] First, the raw electrical energy output from the rectified antenna array enters the board-level RF filter circuit. The filter circuit employs a combination of lumped-parameter and distributed-parameter components. This is a low-pass filter topology. It consists of two parallel feedthrough capacitors and a series microstrip inductor or high-frequency ferrite bead. The feedthrough capacitors, utilizing their coaxial structure, provide an extremely low impedance path to ground at high frequencies, bypassing residual 28GHz or 94GHz fundamental and second harmonic components to the ground shield. The series-connected ferrite bead exhibits high resistance in the radio frequency band, further attenuating high-frequency noise through dissipation, ensuring that the residual radio frequency ripple voltage entering subsequent circuits is below the millivolt level.

[0086] Subsequently, the DC current, after being filtered to remove high-frequency ripple, enters the capacitor buffer layer, which is composed of a supercapacitor module 320. The supercapacitor module 320 is an electrochemical double-layer capacitor (EDLC) with high power density and long cycle life characteristics. In terms of electrical connection, the supercapacitor module 320 is directly connected between the positive and negative terminals of the internal DC bus, serving as an energy buffer unit for the DC bus.

[0087] The main function of the supercapacitor module 320 is to decouple the discreteness of microwave energy transmission from the continuity of battery charging. Because ground base stations employ time-division duplex or beam scanning mechanisms, the energy arriving at the airborne receiving terminal manifests as pulses on the time axis. When illuminated by a high-energy beam, the supercapacitor module 320 utilizes its fast response characteristics to rapidly absorb instantaneous power peaks exceeding the battery's throughput capacity, preventing DC bus voltage overshoot. When the beam moves away or is in a pilot time slot, the supercapacitor module 320 releases stored charge to the load or battery to fill the energy gap.

[0088] To ensure that DC bus voltage fluctuations are controlled within a safe range, the minimum total capacitance value of the supercapacitor module is... The design must satisfy energy conservation and ripple suppression criteria. The calculation is based on the following formula:

[0089] ;

[0090] in, This indicates the average load power of the sector-shaped electrical compartment; This indicates the maximum time gap for microwave power transmission (e.g., beam scan period or pilot time slot length). Indicates the maximum permissible transient voltage of the internal DC bus; This indicates the minimum permissible operating voltage of the internal DC bus.

[0091] Given the relatively low rated voltage of individual supercapacitor cells, a supercapacitor module 320 is typically composed of multiple cells connected in series. The module integrates a voltage equalization circuit. When a cell's voltage exceeds the equalization threshold, the equalization circuit activates a bypass current to dissipate or transfer excess charge, ensuring that the terminal voltages of all cells connected in series remain consistent.

[0092] To achieve long-term storage with high energy density and fine regulation of the internal DC bus voltage, this embodiment employs high-energy-density lithium-sulfur battery technology combined with a bidirectional power flow control strategy.

[0093] The core component of the energy storage layer is the lithium-sulfur battery pack 310. The lithium-sulfur battery pack 310 is composed of several lithium-sulfur single cells connected in series and parallel. Its positive electrode material is a sulfur-carbon composite material, and its negative electrode material is a lithium metal sheet or lithium alloy, and its surface is coated with a solid electrolyte interface (SEI) protective film.

[0094] The lithium-sulfur battery pack 310 is connected to the internal DC bus via a bidirectional DC-DC converter. In terms of circuit topology, the bidirectional DC-DC converter employs an interleaved parallel half-bridge topology. This topology includes two or more parallel power branches, each consisting of an upper bridge arm switch, a lower bridge arm switch, and a filter inductor. Silicon carbide (SiC) MOSFETs are used as the switching transistors. The interleaved parallel control method ensures that the inductor current waveforms of each phase are phase-shifted, thereby reducing the total current ripple flowing to the battery side.

[0095] The operation of this bidirectional DC-DC converter is controlled by the PWM signal of the local controller, and it has two basic operating modes: buck charging and boost discharging. When the power output of the impedance adaptive rectifier antenna array 400 is greater than the load power, the converter operates in Buck mode to control the charging current; when the output power of the rectifier antenna is insufficient, the converter operates in Boost mode to support the internal DC bus.

[0096] To achieve rational power allocation in the hybrid energy storage system, the control system employs a frequency-based power decoupling strategy. The core logic of this strategy is that the supercapacitor module 320 naturally responds to high-frequency power fluctuations using its physical characteristics, while the lithium-sulfur battery pack 310 only responds to smoothed power commands after low-pass filtering. The control system collects the load current. and rectified output current A battery reference current is generated through a low-pass filter. The transfer function of this control algorithm is expressed as follows:

[0097] ;

[0098] in, For the Laplace operator; This is the time constant of the low-pass filter, and its value is set to range from 1 second to 10 seconds. To account for the compensation factor of the battery's state of charge (SOC). When When the converter switches to Boost mode; when At that time, the converter switches to Buck mode.

[0099] Based on the generated reference current The bidirectional DC-DC converter employs a dual closed-loop control architecture consisting of an inner current loop and an outer voltage loop. The outer voltage loop intervenes in Boost discharge mode, introducing a virtual impedance or droop control coefficient. This causes the voltage of the internal DC bus to decrease slightly as the output current increases, thus ensuring automatic load balancing when multiple sector-shaped battery cells are connected in parallel. Furthermore, the battery management system integrates a real-time coulomb efficiency estimation algorithm to dynamically correct the SOC estimate.

[0100] In terms of thermal safety, the power devices and inductors of the bidirectional DC-DC converter are all mounted close to the microchannel liquid cooling plate. When the monitored temperature exceeds a preset threshold, the control system forcibly reduces the reference current amplitude or directly shuts down the converter.

[0101] To address the high heat flux generated by high-power microwave rectification and the heat accumulation of lithium-sulfur battery packs during charging and discharging, this embodiment constructs a closed-loop active thermal management system.

[0102] The unified liquid cooling circuit runs through the entire fan-shaped battery compartment 210 in its physical layout. This circuit consists of micro-circulating pumps, liquid storage tanks, microchannel cold plate arrays, and skin heat exchangers connected in series or parallel. In terms of fluid path planning, the cryogenic working fluid first flows through the temperature-sensitive lithium-sulfur battery pack 310, then through the back heat dissipation layer of the impedance adaptive rectifier antenna array 400, and finally through the bidirectional DC-DC converter power module with the highest heat dissipation power density, thus achieving cascaded heat utilization.

[0103] The cooling medium circulating in the circuit is a phase change working fluid, specifically a microencapsulated phase change material (MPCM) suspension. This suspension uses deionized water or ethylene glycol aqueous solution as the base liquid, in which micron-sized phase change capsule particles are uniformly dispersed. The phase change temperature of the phase change core material is set between 40°C and 50°C.

[0104] A microchannel cold plate is integrated on the back of the impedance adaptive rectifier antenna array 400. When high-power microwave irradiation causes the temperature of the rectifier diodes to rise, the heat is conducted through the heat dissipation vias to the metal substrate of the microchannel cold plate and then transferred to the phase change working fluid flowing through the microchannel.

[0105] The endothermic process of phase change working fluids within microchannels comprises two stages: sensible heat absorption and latent heat absorption. Its maximum theoretical heat transfer capacity... The calculation model is shown below:

[0106] ;

[0107] in, The mass flow rate of the working fluid; This represents the mass fraction of the microcapsule particles. The specific heat capacity of the base liquid; The specific heat capacity of the capsule particles; and These are the fluid temperatures at the inlet and outlet of the microchannel, respectively. This refers to the latent heat of fusion of the phase change core material. When the working fluid reaches the phase change temperature, it can absorb a large amount of latent heat through phase change, achieving isothermal cooling.

[0108] Subsequently, the high-temperature working fluid, after absorbing heat, flows to the outer skin of the aircraft's annular equipment bay. An integrated heat exchanger on the inner side of the skin utilizes the strong convective cooling effect of the external airflow to dissipate heat into the atmosphere.

[0109] Finally, the micro-circulating pump driving the working fluid flow is regulated by the thermal management controller 500. The controller adjusts the pump speed using a PWM signal based on feedback from the temperature sensor.

[0110] This embodiment adopts a technical solution that combines passive radiative heat dissipation with active thermal-fluid coupling control.

[0111] A wide-band, high-emissivity thermal control coating is sprayed onto the non-transparent skin surface of the fan-shaped electrical compartment 210. This thermal control coating has a hemispherical emissivity higher than 0.85 in the atmospheric window band of 8 to 14 micrometers and the full infrared band. This design takes advantage of the environmental characteristics of the thin atmosphere and extremely low background temperature at high altitudes, dissipating waste heat directly into the cold black space through thermal radiation.

[0112] Radiant heat dissipation power Following the Stefan-Boltzmann law, the calculation model is as follows:

[0113] ;

[0114] in, The surface emissivity of the thermal control coating; It is the Stefan-Boltzmann constant; The effective area of ​​the radiative heat dissipation surface; The absolute temperature of the outer surface of the skin; The equivalent background temperature of the high-altitude environment; is the field factor.

[0115] The active thermal management layer employs a thermal-fluid coupling control strategy. The thermal management controller 500 receives temperature signals from the rectifier antenna array. Battery pack temperature signal and microwave receiving power signal Based on these inputs, the controller adjusts the rotational speed of the micro-circulating pump to compensate in real time for the effect of changes in the viscosity of the phase change working fluid caused by temperature variations on the flow resistance characteristics.

[0116] To address the pulsed nature of microwave power transmission, this embodiment employs a composite control algorithm based on power feedforward. When the airborne receiving terminal detects a power transmission synchronization signal from the ground base station, the controller increases the flow rate of the circulating pump in advance. The controller's flow rate command... The calculation formula is as follows:

[0117] ;

[0118] in, This is the difference between the current measured temperature and the set target temperature. and These are the proportional and integral coefficients, respectively. This is the feedforward gain coefficient; The predicted microwave received power at the next moment; The effective specific heat capacity of the phase change working fluid; To design the target temperature rise value.

[0119] In addition, the thermal management controller has built-in fail-safe logic. When a circulation pump failure is detected, the controller forcibly cuts off the main power path of the bidirectional DC-DC converter and uses passive radiative cooling to maintain standby mode.

[0120] The energy management system collects the status parameters of the energy source, storage, and load in real time and maps them into standardized power demand commands.

[0121] The status acquisition layer obtains DC bus voltage, branch current, and key point temperature through a sensor network. All analog signals are processed by a low-pass filter and then sent to the control core for discretization sampling.

[0122] After acquiring the raw data, the system enters the state estimation stage. This embodiment uses the extended Kalman filter (EKF) algorithm, combined with the second-order RC equivalent circuit model of the battery, to correct the state of charge (SOC) and state of health (SOH) of the lithium-sulfur battery pack in real time.

[0123] Subsequently, the demand mapping logic categorizes the loads into three types: Level 1 critical loads, Level 2 adjustable loads, and Level 3 elastic loads. The controller aggregates the power consumption of each load in real time and, combined with the charging needs of the energy storage units, calculates the total power demand. .

[0124] Total power demand The calculation formula is as follows:

[0125] ;

[0126] in, The baseline power consumption for a Level 1 critical load; Peak power consumption for level 2 and level 3 loads; The load enable factor; For the estimated conversion efficiency of the back-end DC-DC converter; The target state of charge of the battery; This is the currently estimated state of charge; This refers to the rated capacity of the battery pack. This is the charging power conversion factor.

[0127] Finally, the controller will calculate the... Compared to the maximum available output power of current microwave rectified antenna arrays The comparison is performed to generate the final power allocation command, which is then adjusted. The coefficient enables load shedding or derating to ensure that the DC bus voltage remains above the safe threshold.

[0128] The system employs a framed transmission mechanism, dividing the time axis into consecutive superframes. Each superframe consists of a synchronization pilot time slot, a power transmission time slot, a communication telemetry time slot, and a guard interval.

[0129] The synchronization controller of the airborne receiver terminal executes the time slot synchronization logic. Upon receiving the rising edge of the synchronization pilot signal transmitted from the ground, the local clock counter is reset and begins counting. The synchronization controller uses a sliding window averaging algorithm to predict the precise arrival time of the next frame's power transmission time slot. and end time .

[0130] Based on the synchronized timing reference, the energy management system performs beam scheduling request calculations. The airborne terminal needs to request a suitable power transmission duty cycle from the ground station based on its own load requirements and energy storage status. (Request duty cycle) The calculation formula is as follows:

[0131] ;

[0132] in, This is the predicted average power consumption of the current airborne equipment; To meet the charging power requirements of battery packs and supercapacitors; This is the estimated peak received power within the power transmission time slot under the current link path loss. This refers to the conversion efficiency of the rectified antenna array at the current input power density. This is the safety margin coefficient.

[0133] Subsequently, the calculations were obtained The real-time GPS / BeiDou coordinates or beam alignment deviation angle of the airborne terminals are encapsulated in a communication telemetry frame and sent to the ground control station. The ground station performs spatiotemporal joint arbitration based on requests from multiple airborne terminals. If the ground station approves the request, it will confirm the allocated time slot length and starting offset in the control signaling of the next frame. At this time, the airborne energy management system generates an energy receiving window signal.

[0134] Before the energy receiving window opens, the energy management system triggers the impedance adaptive adjustment network to switch it to a high-power matching state, and simultaneously instructs the bidirectional DC-DC converter to enter energy absorption mode. This pre-triggering mechanism eliminates hardware response delay.

[0135] After the power transmission time slot ends and the system enters the protection interval, it automatically performs state maintenance and mode switching. At this time, the rectifier antenna array has no microwave input, and the energy management system instructs the supercapacitor module to enter the discharge mode to fill the energy gap in the non-transmission time slot and maintain the voltage stability of the DC bus.

[0136] Specific application example: Long-endurance microwave power replenishment system for near-space stratospheric airships

[0137] Application scenarios and basic system configuration:

[0138] This embodiment applies the ring-shaped distributed hybrid energy storage and in-flight wireless energy replenishment system to a stratospheric communication airship codenamed "Sky Sentinel-I".

[0139] The system parameters are configured as follows:

[0140] Airborne receiver terminal 200: A ring-shaped receiving system with a diameter of 30 meters is conformally installed at the largest diameter (equatorial plane) in the middle of the airship.

[0141] The compartmentalized structure is divided into 12 physically isolated sector-shaped electrical compartments (numbered S1-S12) along the circumference, with each sector covering a 30-degree angle.

[0142] Antenna configuration: 28GHz (Ka band) circularly polarized rectified antenna array.

[0143] Energy storage configuration: Each sector is equipped with a 2kWh lithium-sulfur battery pack (energy density 400Wh / kg) and a 50Wh supercapacitor module.

[0144] Thermal management: Microencapsulated phase change fluid (MPCM) with a phase change temperature of 45℃ is used.

[0145] Ground transmission base station 100: Deployed on the plateau, with a peak transmission power of 100kW, and adopts a 4096-element millimeter-wave phased array.

[0146] Operating mechanism: It adopts TDD mode with a duty cycle of 20% (2ms pilot detection, 8ms power transmission).

[0147] Workflow and dynamic response demonstration:

[0148] Step 1: Attitude Sensing and Impedance Adaptive Modulation. Assume the airship's attitude changes due to airflow, causing sectors S4, S5, and S6 to face the ground base station, while S3 and S7 are at the beam edge. The control routing module detects that the SOC of batteries S4-S6 is below 40% and generates a charging command.

[0149] Target sector (S4-S6): The system adjusts its impedance to a "conjugate matched state".

[0150] Corresponding diagram: as shown Figure 3 As shown, the voltage reflection coefficients (line graph, right axis) of sectors S4, S5, and S6 drop below 0.1 (close to 0), indicating that they are in a state of full absorption; the corresponding received power (bar graph, left axis) increases, with the power of sector S5, which is directly in the center, reaching a peak of about 100W, while the power of sectors S4 and S6 on both sides is about 70W.

[0151] Non-target sectors (S3, S7 and others): The system adjusts them to "total reflection mismatch state".

[0152] Corresponding diagram: as shown Figure 3As shown, the reflection coefficients (line graph) of edge sectors S3 and S7 and the back-facing sector remain around 0.95 (close to 1), exhibiting high-impedance total reflection characteristics; the corresponding received power (bar graph) is suppressed to below 5W. This differs from traditional schemes where inefficient reception often exists at the beam edges. This system completely cuts off the ineffective energy paths at the edges and back through active mismatch.

[0153] Step 2: Pilot Detection and Beamforming. The ground base station transmits low-power pilot signals. Since S4-S6 are in a matched state (small echo), while S3, S7, etc. are in a mismatched state (large echo), the beam controller calculates S4-S6 as the target area based on the echo difference and generates a high-gain narrow beam weight that only covers these three sectors.

[0154] Step 3: Pulse transmission and hybrid energy storage buffering. The ground base station enters the power transmission time slot and transmits microwave pulses.

[0155] Pulse characteristics: such as Figure 4 As shown by the dashed line (microwave input pulse), microwave energy is injected in the form of pulses, and the high-level duration is approximately 20% of the entire cycle (in accordance with TDD settings).

[0156] Voltage regulation effect:

[0157] Traditional solution ( Figure 4 (Thick solid line): marked as "Traditional battery powered (large ripple)". During the arrival of the microwave pulse, due to the lack of fast buffering, the DC bus voltage fluctuates with the power pulse. As shown in the figure, the voltage is pulled up to about 272V, exhibiting sawtooth fluctuations at the same frequency as the pulse.

[0158] The present invention solution ( Figure 4 (Thin solid line): labeled "Hybrid Energy Storage of This Invention (Low Ripple)". The supercapacitor module inside the S5 utilizes its low impedance characteristics to instantly absorb power peaks (arrow in the diagram "Supercapacitor Clamping Effect"). As shown in the figure, the DC bus voltage is firmly clamped at the 270V baseline, the voltage curve is smooth and flat, and the ripple amplitude is visually less than 2%, ensuring a clean power supply to the downstream load.

[0159] Step 4: As high-power rectification continues (test duration 600 seconds), the thermal management system is activated.

[0160] Risks of traditional solutions: such as Figure 5 As shown by the dashed line, in the thin atmosphere at an altitude of 20km, the device temperature rises approximately linearly with time, exceeding the device's safety limit of 80℃ at about 300 seconds, posing a risk of overheating and burnout.

[0161] Effects of the invention: such as Figure 5 As shown by the solid line:

[0162] 0-200 seconds: Temperature rises with power injection.

[0163] 200 seconds later (phase transition point): When the temperature reaches 45℃ (phase transition temperature), the curve shows a clear inflection point and enters the "phase transition isothermal plateau region".

[0164] Steady-state maintenance: By utilizing the latent heat absorption of the MPCM working fluid, the temperature of the core device was locked below 50°C for the remaining 400 seconds, which is far below the safety threshold, verifying the thermal stability of the system under long-term high-power operation.

[0165] Experimental Verification Summary

[0166] Comparative analysis based on the attached data:

[0167] Energy space management capabilities (attached) Figure 3 The system achieves digital on-demand energy allocation, with S5 peak receiving power reaching 100W, while the power of adjacent mismatched sectors is suppressed to below 5W, resulting in an extremely high signal-to-noise ratio.

[0168] Power quality (with appendix) Figure 4 ): The hybrid energy storage architecture eliminates voltage fluctuations caused by TDD, reducing voltage ripple from visible fluctuations in traditional solutions to near-zero fluctuations (<2%).

[0169] Thermal survivability (with appendix) Figure 5 Phase change thermal management reduces the core temperature limit from >80℃ (runaway) of traditional air cooling and locks it at 50℃ (safe), supporting the system's long-endurance operation.

Claims

1. A ring-shaped distributed hybrid energy storage and in-flight wireless power replenishment system, characterized in that, include: The ground-based transmission base station (100) is equipped with a millimeter-wave phased array (110) for transmitting microwave energy beams and performing beam scanning; An airborne receiving terminal (200) is integrated into the aircraft and includes multiple physically isolated sector-shaped electronic bays (210) distributed circumferentially. Each of the aforementioned sector-shaped electrical compartments (210) integrates: The antenna array module (400) is laid on the surface of the outer skin and is used to receive the microwave energy beam and convert it into DC power, and has an adjustable input impedance; The hybrid energy storage module (300), electrically connected to the antenna array module (400), includes a lithium-sulfur battery pack (310) and a supercapacitor pack (320). The control routing module (600) is electrically connected to each of the fan-shaped battery compartments (210) and is used to collect battery status and generate a global state vector, control the antenna array module (400) to switch between impedance matching state and impedance mismatch state, and adjust the absorption or reflection characteristics of the fan-shaped battery compartments (210) for the microwave energy beam.

2. The ring-shaped distributed hybrid energy storage and in-flight wireless power replenishment system according to claim 1, characterized in that, The ground transmission base station (100) also includes a beam controller (120), which is used for: During the pilot detection time slot, based on the amplitude difference of the echo signal received by the millimeter-wave phased array (110), the spatial orientation and impedance state of each of the sector-shaped electric cells (210) are inverted and calculated. During the power transmission time slot, a beamforming weight vector is generated based on the solution results, and the millimeter-wave phased array (110) is controlled to make the energy focus of the transmitted beam cover the region in the impedance matching state and form an energy null trap in the region in the impedance mismatch state.

3. The ring-shaped distributed hybrid energy storage and in-flight wireless power replenishment system according to claim 1, characterized in that, The impedance control logic of the control routing module (600) is as follows: When the state of charge of the lithium-sulfur battery pack (310) in the fan-shaped battery compartment (210) is lower than a preset threshold and the temperature is normal, the corresponding antenna array module (400) is controlled to switch to the conjugate matching state so that the voltage reflection coefficient approaches zero. When the state of charge of the lithium-sulfur battery pack (310) in the fan-shaped battery compartment (210) is higher than a preset threshold or a fault occurs, the corresponding antenna array module (400) is controlled to switch to the total reflection mismatch state, so that the voltage reflection coefficient approaches one.

4. The ring-shaped distributed hybrid energy storage and in-flight wireless power replenishment system according to claim 3, characterized in that, The antenna array module (400) in the total reflection mismatch state increases the radar cross section by having a high reflection coefficient, and serves as a passive physical layer beacon to reflect pilot signals so that the ground transmitting base station (100) can identify the current area as a non-charging target area.

5. The ring-shaped distributed hybrid energy storage and in-flight wireless power replenishment system according to claim 1, characterized in that, The electrical topology of the hybrid energy storage module (300) is as follows: the supercapacitor group (320) is directly connected in parallel to the internal DC bus at the output end of the antenna array module (400) for clamping voltage; The lithium-sulfur battery pack (310) is connected to the internal DC bus via a bidirectional DC converter, which responds to low-frequency power commands according to a frequency decoupling strategy.

6. The ring-shaped distributed hybrid energy storage and in-flight wireless power replenishment system according to claim 5, characterized in that, The ground-based transmitting base station (100) and the airborne receiving terminal (200) are configured to perform energy exchange in time-division duplex mode, and the supercapacitor bank (320) is used for: During the arrival of microwave pulses in the power transmission time slot, the instantaneous power peak is absorbed by utilizing the low impedance characteristics, thus limiting the voltage ripple of the internal DC bus to a preset range. During pilot detection time slots or beam scanning gaps, charge is released to the internal DC bus to maintain power supply continuity.

7. The ring-shaped distributed hybrid energy storage and in-flight wireless power replenishment system according to claim 1, characterized in that, The antenna array module (400) includes a multilayer dielectric substrate and microstrip patch antenna units integrated thereon, and each microstrip patch antenna unit is connected in series with an impedance modulation circuit to the rectifier circuit. The impedance modulation circuit includes a PIN diode, and the control routing module (600) modulates the input impedance by adjusting the bias voltage applied to the PIN diode to change the equivalent reactance of the radio frequency path.

8. The ring-shaped distributed hybrid energy storage and in-flight wireless power replenishment system according to claim 1, characterized in that, It also includes a thermal management module (500), which includes a fluid loop and a micro circulation pump that runs through the sector-shaped electrical compartment (210); The fluid circuit is filled with microcapsule phase change fluid, which contains phase change capsule particles suspended in a base fluid, and the phase change temperature of the phase change capsule particles is set between 40°C and 50°C.

9. A ring-shaped distributed hybrid energy storage and in-flight wireless power replenishment system according to claim 8, characterized in that, The internal components of the fan-shaped battery compartment (210) are stacked, and from the outside to the inside are the antenna array module (400), the microchannel liquid cooling plate and the hybrid energy storage module (300). The microchannel liquid cooling plate is connected to the fluid circuit and is used to transfer the heat generated by the antenna array module (400) to the microcapsule phase change fluid; The non-transparent skin surface of the fan-shaped electrical compartment (210) is provided with a radiative heat dissipation surface for radiating the heat of the microcapsule phase change fluid flowing through it to the external environment.

10. A ring-shaped distributed hybrid energy storage and in-flight wireless power replenishment system according to claim 1, characterized in that, The ground-based transmitting base station (100) and the airborne receiving terminal (200) are configured to operate collaboratively based on a superframe structure, with each superframe containing a pilot detection time slot and a power transmission time slot; Before the power transmission time slot begins, the control routing module (600) pre-triggers the sector battery compartment (210) with charging needs to enter the impedance matching state, and simultaneously instructs the hybrid energy storage module (300) to enter the energy absorption mode.

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