Power balance control method of distributed electric propulsion system

Abstract

The invention discloses a power balance control method for a distributed electric propulsion system, and the method is based on the system architecture of the distributed electric propulsion system, and the method comprises the steps: detecting the position and type of a fault when the distributed electric propulsion system with balanced power breaks down, and enables the output power of four storage battery packs to be unbalanced; the fault position comprises at least one of a storage battery pack BAT, a propulsion motor M, a propulsion motor controller C and a feeder line fault; executing power supply conversion control according to the detected fault position and type, and executing power balance control when the output power of the storage battery pack is unbalanced; according to the power balance control mode, electric energy dispatching between bus bars is achieved by adjusting a feeder change-over switch at the front end of a corresponding propulsion motor controller C, so that unbalance of output power of a storage battery pack is reduced or eliminated. According to the technical scheme provided by the invention, flexible electric energy dispatching is realized, and the problem of unbalanced output power of the storage battery pack is greatly reduced or even eliminated.

Description

Technical Field

[0001] The present invention relates to, but is not limited to, the technical field of distributed electric propulsion aircraft, and in particular to a power balance control method for a distributed electric propulsion system. Background Art

[0002] For a long time, due to the continuous growth of aviation transportation, aviation emissions of carbon oxides, nitrogen oxides, and noise have been increasing, and new power methods are needed. The use of electric propulsion technology can greatly reduce carbon oxides, nitrogen oxides, and noise emissions, and promote the realization of green environmental protection development goals. In addition, the use of electric propulsion technology can improve energy utilization efficiency and improve flight economy.

[0003] At present, the efficiency of turbofan engines in utilizing fuel energy is only about 40%, while the utilization rate of electric propulsion systems in utilizing electrical energy can exceed 70%, which means that the use of electric propulsion technology has the potential to improve the overall efficiency of the system, and can reduce fuel consumption, that is, improve flight economy. Thanks to the "scale-independent" nature (after a high-power electric motor is decomposed into several small-power electric motors, the power density and efficiency of the entire system remain basically unchanged), the distributed electric propulsion power system can integrate the aircraft power system into the aircraft aerodynamic layout, achieving the best fusion of aerodynamics, structure, and power to reduce weight and drag, thereby improving the efficiency of the entire aircraft.

[0004] At present, the research on electric propulsion aircraft is mainly focused on small-power centralized electric propulsion for general aviation. The research on distributed electric propulsion systems is still in the early theoretical and scaled-down ground test exploration stage, and the battery packs in the distributed electric propulsion system have the problem of unbalanced output power. Summary of the invention

[0005] Purpose of the present invention: In order to solve the above technical problems, an embodiment of the present invention provides a power balance control method for a distributed electric propulsion system to achieve flexible power scheduling and significantly reduce or even eliminate the problem of unbalanced output power of the battery group.

[0006] The technical solution of the present invention: An embodiment of the present invention provides a power balance control method for a distributed electric propulsion system, wherein the distributed electric propulsion system comprises: a left A channel (AL) and a right A channel (AR) symmetrically distributed on both sides of a distributed electric propulsion aircraft, and a left B channel (BL) and a right B channel (BR) symmetrically distributed, wherein the A channel is located inside the B channel, and the four channels include four bus bars (BL BUS, AL BUS, AR BUS, BR BUS), four battery packs (BL BAT, AL BAT, AR BAT, BR BAT), and a power supply unit (BAT). BAT), 4 main channel contactors (BLC, ALC, ARC, BR), 2 conversion channel contactors (BTC1, BTC2), 4n feeder transfer switches, 4n fuses, 4n propulsion motor controllers, 4n propulsion motors, 4n circuit breakers and 4n propellers, and a system control unit, wherein n is a positive integer greater than or equal to 1; wherein the battery pack in each channel is connected to the bus bar through a main channel contactor, the bus bar is powered by the battery pack, and the on-off state of the battery pack and the bus bar in each channel is controlled by the main channel contactor; the bus bar AL BUS of the left channel A and the bus bar AR BUS of the right channel A are connected through the conversion channel contactor BTC1, and the bus bar BL BUS of the left channel B is connected through the conversion channel contactor BTC2. BUS and the bus bar BRBUS of the right B channel are connected through the conversion channel contactor BTC2, and the on-off state between the two end buses connected thereto is controlled by each conversion channel contactor; in the left A channel (AL) and the left B channel (BL), each propulsion motor controller is selectively powered by BL BUS or AL BUS through a feeder conversion switch, and in the right A channel (AR) and the right B channel (BR), each propulsion motor controller is selectively powered by AR BUS or BR BUS through a feeder conversion switch, and a fuse for overcurrent protection is connected between the propulsion motor controller and the feeder conversion switch; the system control unit is respectively connected to each battery pack, each bus bar, each main channel contactor, each conversion channel contactor, and each feeder conversion switch;

[0007] The power balance control method of the distributed electric propulsion system includes:

[0008] When a power-balanced distributed electric propulsion system fails so that the output power of the four battery packs is unbalanced, the fault location and type are detected; the fault location includes: at least one of the battery pack BAT, the propulsion motor M, the propulsion motor controller C, and the feeder fault;

[0009] According to the detected fault location and type, power supply conversion control is performed, and power balancing control is performed when the output power of the battery pack is unbalanced; the power balancing control method is: by adjusting the feeder conversion switch at the front end of the corresponding propulsion motor controller C, power scheduling between the bus bars is achieved to reduce or eliminate the output power imbalance of the battery pack.

[0010] Optionally, in the power balance control method of the distributed electric propulsion system as described above, the power balance control method includes:

[0011] Step 1, obtaining the status of each component in the distributed electric propulsion system, including: the battery pack, the contactor, the feeder transfer switch, the propulsion motor, the propulsion motor controller, and the fault status of the feeder transfer switch, and determining whether power supply conversion control needs to be executed according to the status of each component in the system;

[0012] Step 2: When the power supply status of each component in the system changes, the power supply conversion control of the system is completed according to the power supply mode and power supply conversion form of the system;

[0013] Step 3, detecting the output status of the available battery packs and determining whether the output power of the battery packs is balanced;

[0014] Step 4, when it is determined in step 3 that the output power of the available battery packs is unbalanced, power balancing control is performed, including: by adjusting the feeder conversion switch, each available battery pack supplies power to the same number of propulsion motor controllers as much as possible, so that the available battery packs achieve power balance; when it is determined in step 3 that the output power of the available battery packs is balanced, power balancing control is skipped, and the status of each component in the system is updated, and a new round of power supply conversion control or power balancing control is performed.

[0015] Optionally, in the power balance control method of the distributed electric propulsion system as described above, in the distributed electric propulsion system, the battery pack BL BAT is connected to the bus bar BL BUS via the main channel contactor BLC; the battery pack AL BAT is connected to the bus bar AL BUS via the main channel contactor ALC; the battery pack AR BAT is connected to the bus bar AR BUS via the main channel contactor ARC; the battery pack BR ​​BAT is connected to the bus bar BR BUS via the main channel contactor BRC;

[0016] In the distributed electric propulsion system, the feeder conversion switch S1 controls whether the propulsion motor controller C1 is powered by the bus BL BUS or the bus AL BUS; the feeder conversion switch S7 controls whether the propulsion motor controller C7 is powered by the bus BL BUS or the bus AL BUS; the feeder conversion switch S6 controls whether the propulsion motor controller C6 is powered by the bus BL BUS or the bus AL BUS; the feeder conversion switch S4 controls whether the propulsion motor controller C4 is powered by the bus AL BUS or the bus BL BUS; the feeder conversion switch S10 controls whether the propulsion motor controller C10 is powered by the bus AL BUS or the bus BL BUS; the feeder conversion switch S5 controls whether the propulsion motor controller C5 is powered by the bus AL BUS or the bus BL BUS; the feeder conversion switch S3 controls whether the propulsion motor controller C3 is powered by the bus AR BUS or the bus BR BUS; the feeder conversion switch S9 controls whether the propulsion motor controller C9 is powered by the bus AR BUS. The feeder conversion switch S11 controls whether the propulsion motor controller C11 is powered by the bus bar AR BUS or the bus bar BR BUS; the feeder conversion switch S2 controls whether the propulsion motor controller C2 is powered by the bus bar BR BUS or the bus bar AR BUS; the feeder conversion switch S8 controls whether the propulsion motor controller C8 is powered by the bus bar BR BUS or the bus bar AR BUS; the feeder conversion switch S12 controls whether the propulsion motor controller C12 is powered by the bus bar BR BUS or the bus bar AR BUS.

[0017] Optionally, in the power balance control method of the distributed electric propulsion system as described above, the state information of the four battery packs, and the on-off states of the corresponding four main channel contactors and two conversion channel contactors form 16 power supply states of the distributed electric propulsion system and form 64 power supply conversion modes;

[0018] The power supply logic table of the distributed electric propulsion system is:

[0019]

[0020]

[0021] The 64 power supply conversion modes include the following bidirectional conversions: 1) State 1 <—> State 2;

[0022] 2) State 1 <—> State 3;

[0023] 3) State 1 <—> State 4;

[0024] 4) State 1 <—> State 5;

[0025] 5) State 2 <—> State 6;

[0026] 6) State 2 <—> State 7;

[0027] 7) State 2 <—> State 8;

[0028] 8) State 3 <—> State 6;

[0029] 9) State 3 <—> State 9;

[0030] 10) State 3 <—> State 10;

[0031] 11) State 4 <—> State 7;

[0032] 12) State 4 <—> State 9;

[0033] 13) State 4 <—> State 11;

[0034] 14) State 5 <—> State 8;

[0035] 15) State 5 <—> State 10;

[0036] 16) State 5 <—> State 11;

[0037] 17) State 6 <—> State 12;

[0038] 18) State 6 <—> State 13;

[0039] 19) State 7 <—> State 12;

[0040] 20) State 7 <—> State 14;

[0041] 21) State 8 <—> State 13;

[0042] 22) State 8 <—> State 14;

[0043] 23) State 9 <—> State 12;

[0044] 24) State 9 <—> State 15;

[0045] 25) State 10 <—> State 13;

[0046] 26) State 10 <—> State 15;

[0047] 27) State 11 <—> State 14;

[0048] 28) State 11 <—> State 15;

[0049] 29) State 12 <—> State 16;

[0050] 30) State 13 <—> State 16;

[0051] 31) State 14 <—> State 16;

[0052] 32)State 15<—>State 16.

[0053] Optionally, in the power balance control method of the distributed electric propulsion system as described above, in step 4, the distributed electric propulsion system performs power balance control by using an ant colony algorithm, and the ant colony algorithm design method includes:

[0054] S1, the objective function for designing the battery pack for power balance control of distributed electric propulsion system to minimize the cost of powering the motor is:

[0055] Among them, Cost i,j represents the cost of the i-th battery pack to perform the j-th task, N represents the total number of available battery packs, num i Represents the number of motors powered by the i-th battery pack.

[0056] S2, determine the constraints of the objective function, including: battery pack load capacity constraints, power balance constraints, propulsion motor constraints,

[0057] Optionally, in the power balance control method of the distributed electric propulsion system as described above, the constraints in S2 are:

[0058] 1) Battery pack load capacity constraint: Each available battery pack can only power up to 6 propulsion motors, that is, 1≤num i ≤6;

[0059] Among them, num i Indicates the number of motors powered by the i-th battery pack.

[0060] 2) Power balance constraint: To ensure power balance, the difference in the number of propulsion motors corresponding to each battery pack should not be greater than 1, that is:

[0061] num a -num b ≤1, a=(1,2,...,N), b=(1,2,...,N) and a≠b;

[0062] 3) Propulsion motor constraints: A propulsion motor can only be powered by one battery pack, that is: And a≠b;

[0063] Among them, task aRepresents the set of motors powered by the ath battery pack. b represents the set of motors powered by the bth battery pack;

[0064] 4) Constraints on the power supply capacity of the battery pack: Based on the different states of the two conversion channel contactors, the power supply capacity of each battery pack to each propulsion motor is obtained as follows:

[0065]

[0066] ability i Indicates the ability of the i-th battery pack to supply power to the 12 propulsion motors. 1 indicates that the battery pack can supply power to the motor, and 0 indicates that it cannot supply power. Ability1, Ability2, Ability3, and Ability4 represent BLBAT power supply capability, AL BAT power supply capability, AR BAT power supply capability, and BR BAT power supply capability, respectively.

[0067] 5) Limit the power supply cost of the propulsion motor:

[0068] Under different working conditions, the cost of each battery pack supplying power to each propulsion motor is as follows:

[0069]

[0070] Among them, Cost1, Cost2, Cost3, and Cost4 respectively represent: BL BAT is the motor power supply cost, AL BAT is the motor power supply cost, AR BAT is the motor power supply cost, and BR BAT is the motor power supply cost. When BTC2=0, it means that when BTC2 is disconnected, combined with the power supply capacity constraint of the battery pack, the battery pack provides the power supply cost for the motors it can power in order.

[0071] Optionally, in the power balance control method of the distributed electric propulsion system as described above, the manner of implementing power balance control based on the designed ant colony algorithm includes:

[0072] Step 51, collecting the power supply status of each battery pack and each propulsion motor, and updating the status of the battery pack and the propulsion motor;

[0073] Step 52, initializing parameters: the number of available battery packs is N, the number of available propulsion motors is M, and the parameters related to the ant colony algorithm, such as the total number of ants is ant_num, and the maximum number of iterations is NC_max; initializing the taboo table of each ant to be empty, the taboo table is used to record the propulsion motors that each ant has selected in the current path, so as to avoid the ant from repeating the path;

[0074] Step 53, randomly selecting an unpowered available propulsion motor for ant k from the M propulsion motors, calculating the transfer probability, and selecting a propulsion motor that can be powered for the battery pack;

[0075] Step 54, update the taboo table to record the propulsion motors that ant k has selected. Repeat step 3 until all ants have no propulsion motors to choose from, and then end the tour; that is, exit the loop of step 54 and step 53, and execute step 55;

[0076] Step 55, determine whether the current power distribution satisfies the above constraints. If so, calculate the objective function value of the power distribution result of each ant and record the optimal power supply result of this iteration, that is, obtain the propulsion motor corresponding to each available battery pack, and update the pheromone. The specific pheromone update expression is shown in the following formula; otherwise, return to step 53;

[0077] Step 56: If the number of iterations NC reaches the maximum value NC_max, the optimal power supply result is output and the algorithm ends; otherwise, NC=NC+1, and the process returns to step 3.

[0078] Optionally, in the power balance control method of the distributed electric propulsion system as described above, in step 53, the calculation formula for calculating the transfer probability of the ant from the i-th available battery pack to the selected unpowered j-th propulsion motor is as follows:

[0079]

[0080] Among them, τ ij (t) represents the pheromone concentration value from the i-th battery pack to the j-th motor, η ij (t) is the heuristic function, and the inverse of the cost of the battery pack to power the motor is selected as the heuristic function. α is the pheromone heuristic factor, which indicates the importance of the pheromone left on the path passed by the ant. β is the expected heuristic factor, which indicates the importance of the heuristic information left by the ant when transferring the node. Allowed represents the set of nodes that have not been visited.

[0081] Beneficial effects of the present invention: A power balancing control method for a distributed electric propulsion system provided by an embodiment of the present invention is based on the system architecture of the distributed electric propulsion system. When a fault occurs in the power-balanced distributed electric propulsion system, causing the output power of four battery groups to be unbalanced, the fault location and type are detected; the fault location includes: battery group BAT, propulsion motor M, propulsion motor controller C, and at least one of the feeder faults; according to the detected fault location and type, power supply conversion control is performed, and power balancing control is performed when the battery group output power is unbalanced; wherein, the power balancing control method is: by adjusting the feeder conversion switch at the front end of the corresponding propulsion motor controller C, the power scheduling between the bus bars is realized to reduce or eliminate the imbalance in the output power of the battery group. In the embodiment of the present invention, a feeder conversion switch is used between the propulsion motor controller and the bus bar, and a bus bar is selected for power supply through the feeder conversion switch to achieve control of the output power balance of the battery pack. Compared with the traditional power supply conversion control, the added power balance control scheme enables the electric propulsion system to achieve flexible power scheduling by adjusting the feeder conversion switches at the front end of each propulsion motor controller when a battery, propulsion motor, or controller fails, thereby significantly reducing or even eliminating the output power imbalance of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0082] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0083] Figure 1 It is a schematic diagram of the layout of various components of the distributed electric propulsion system on an aircraft in an embodiment of the present invention;

[0084] Figure 2 Schematic diagram of the system architecture of a distributed electric propulsion system for executing a power conversion control method in an embodiment of the present invention;

[0085] Figure 3 A schematic diagram of a power supply state conversion relationship of a distributed electric propulsion system in an embodiment of the present invention;

[0086] Figure 4 A flow chart of a power balance control method for a distributed electric propulsion system provided by an embodiment of the present invention;

[0087] Figure 5 An algorithm flow chart of a power balance control method in a power balance control method for a distributed electric propulsion system provided in an embodiment of the present invention;

[0088] Figure 6 This is a control flow chart of the transition from state No. 1 to state No. 2 in an embodiment of the present invention.

[0089] Figure 7 This is a control flow chart of the transition from state No. 2 to state No. 8 in an embodiment of the present invention.

[0090] Figure 8 This is a control flow chart of the transition from state No. 16 to state No. 13 in an embodiment of the present invention.

[0091] Fig. 9 This is a control flow chart of the transition from state No. 13 to state No. 6 in an embodiment of the present invention. DETAILED DESCRIPTION

[0092] In order to make the purpose, technical solution and advantages of the present invention more clear, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other arbitrarily without conflict.

[0093] The above background technology has already explained that the use of electric propulsion technology can improve energy utilization efficiency and flight economy, and explains the advantages of distributed electric propulsion power systems in aircraft power systems. However, the current research on distributed electric propulsion systems is in the early theoretical and scaled-down ground test exploration stage, and the battery packs in the distributed electric propulsion system have the problem of unbalanced output power.

[0094] In order to solve the above problems, an embodiment of the present invention provides a power balance control method for a distributed electric propulsion system. Compared with traditional power supply conversion control, a power balance control strategy is added. When a battery, propulsion motor, or controller fails, the distributed electric propulsion system can achieve flexible power scheduling by adjusting the feeder conversion switches at the front end of each propulsion motor controller, thereby significantly reducing or even eliminating the output power imbalance of the battery group.

[0095] The present invention provides the following specific embodiments which can be combined with each other. The same or similar concepts or processes may not be described in detail in some embodiments.

[0096] Figure 1 It is a schematic diagram of the layout of various components of the distributed electric propulsion system on an aircraft in an embodiment of the present invention; Figure 2 FIG. 1 is a schematic diagram of the system architecture of a distributed electric propulsion system for executing a power conversion control method in an embodiment of the present invention. Figure 1 and Figure 2As shown, the distributed electric propulsion system in the embodiment of the present invention includes: two A channels (including the left A channel AL and the right A channel AR) and two B channels (including the left B channel BL and the right B channel BR) symmetrically distributed on both sides of the distributed electric propulsion aircraft, the A channel is located on the inner side of the B channel, that is, there are 4 channels in the system, and these 4 channels include 4 bus bars (BL BUS, AL BUS, AR BUS, BR BUS), 4 battery packs (BL BAT, AL BAT, AR BAT, BR BAT), 4 main channel contactors (BLC, ALC, ARC, BR), 2 conversion channel contactors (BTC1, BTC2), 4n feeder transfer switches, 4n fuses, 4n propulsion motor controllers, 4n propulsion motors, 4n propellers, and a system control unit, where n is a positive integer greater than or equal to 1.

[0097] like Figure 1 and Figure 2 The structure shown in the figure, the names of the channels and components in the distributed electric propulsion system in the embodiment of the present invention are defined as follows:

[0098] 1) Channels: The two A channels include: the left A channel (i.e., channel AL) and the right A channel (i.e., channel AR); the two B channels include: the left B channel (i.e., channel BL) and the right B channel (i.e., channel BR); wherein the two B channels are outside the two A channels;

[0099] 2) Bus: 4 bus bars include: bus BL BUS, bus AL BUS, bus AR BUS, bus BR BUS;

[0100] 3) Battery pack: 4 battery packs include: battery pack BL BAT, battery pack AL BAT, battery pack ARBAT, battery pack BR ​​BAT;

[0101] 4) Main channel contactor: 4 main channel contactors include: main channel contactor BLC, main channel contactor ALC, main channel contactor ARC, main channel contactor BRC;

[0102] 5) Conversion channel contactor: Two conversion channel contactors are defined as follows: AL BUS and AR BUS are connected through conversion channel contactor BTC1, and BL BUS and BR BUS are connected through conversion channel contactor BTC2;

[0103] 6) Feeder transfer switches: 12 feeder transfer switches include: feeder transfer switch S1, feeder transfer switch S2, feeder transfer switch S3, feeder transfer switch S4, feeder transfer switch S5, feeder transfer switch S6, feeder transfer switch S7, feeder transfer switch S8, feeder transfer switch S9, feeder transfer switch S10, feeder transfer switch S11, feeder transfer switch S12;

[0104] 7) Fuse: 12 fuses include: fuse F1, fuse F2, fuse F3, fuse F4, fuse F5, fuse F6, fuse F7, fuse F8, fuse F9, fuse F10, fuse F11, fuse F12; in this specific implementation scheme, each bus bar is connected to 3 fuses respectively, and is connected to 3 propulsion motor controllers through 3 fuses respectively;

[0105] 8) Propulsion motor controller: 12 propulsion motor controllers include: propulsion motor controller C1, propulsion motor controller C2, propulsion motor controller C3, propulsion motor controller C4, propulsion motor controller C5, propulsion motor controller C6, propulsion motor controller C7, propulsion motor controller C8, propulsion motor controller C9, propulsion motor controller C10, propulsion motor controller C11, propulsion motor controller C12;

[0106] 9) Propulsion motor: 12 propulsion motors include: propulsion motor M1, propulsion motor M2, propulsion motor M3, propulsion motor M4, propulsion motor M5, propulsion motor M6, propulsion motor M7, propulsion motor M8, propulsion motor M9, propulsion motor M10, propulsion motor M11, propulsion motor M12;

[0107] 10) Propellers: 12 propellers include: propeller P1, propeller P2, propeller P3, propeller P4, propeller P5, propeller P6, propeller P7, propeller P8, propeller P9, propeller P10, propeller P11, propeller P12;

[0108] 10) System control unit: The system control unit is connected to each contactor, each feeder transfer switch, each fuse and propulsion motor controller respectively.

[0109] In the embodiment of the present invention, the specific connection structure inside the distributed electric propulsion system is:

[0110] 1) Connection relationship between battery pack and bus bar:

[0111] The battery pack BL BAT is connected via the main channel contactor BLC and the bus bar BL BUS; the battery pack AL BAT is connected via the main channel contactor ALC and the bus bar AL BUS; the battery pack AR BAT is connected via the main channel contactor ARC and the bus bar AR BUS; the battery pack BR ​​BAT is connected via the main channel contactor BRC and the bus bar BR BUS; Figure 1 and Figure 2 shown.

[0112] 2) Connection relationship between each bus bar:

[0113] The bus bar AL BUSS is connected to the bus bar AR BUS through the conversion channel contactor BTC1; the bus bar BL BUS is connected to the bus bar BR BUS through the conversion channel contactor BTC2; Figure 2 shown.

[0114] 3) Connection relationship between feeder transfer switch, fuse and propulsion motor controller;

[0115] Each propulsion motor controller Ci is connected to the corresponding feeder transfer switch Si through the corresponding fuse Fi, i = 1 to 12; in the left channel A (AL) and the left channel B (BL), the feeder transfer switches S1, S7, S6, S4, S10 and S5 are connected to BLBUS and AL BUS respectively; in the right channel A (AR) and the right channel B (BR), the feeder transfer switches S3, S9, S11, S2, S8 and S12 are connected to BR BUS and AR BUS respectively. Based on the above connection relationship, the working principle of the feeder transfer switch and the fuse is:

[0116] The feeder transfer switch S1 controls whether the propulsion motor controller C1 is powered by the bus BL BUS or the bus ALBUS, and the fuse F1 is used for overcurrent protection; the feeder transfer switch S7 controls whether the propulsion motor controller C7 is powered by the bus BL BUS or the bus AL BUS, and the fuse F7 is used for overcurrent protection; the feeder transfer switch S6 controls whether the propulsion motor controller C6 is powered by the bus BL BUS or the bus AL BUS, and the fuse F6 is used for overcurrent protection; the feeder transfer switch S4 controls whether the propulsion motor controller C4 is powered by the bus AL BUS or the bus BL BUS, and the fuse F4 is used for overcurrent protection; the feeder transfer switch S10 controls whether the propulsion motor controller C10 is powered by the bus AL BUS or the bus BL BUS, and the fuse F10 is used for overcurrent protection; the feeder transfer switch S5 controls whether the propulsion motor controller C5 is powered by the bus ALBUS or the bus BL The feeder transfer switch S3 controls whether the propulsion motor controller C3 is powered by the bus bar AR BUS or the bus bar BR BUS, and the fuse F3 is used as an overcurrent protection; the feeder transfer switch S9 controls whether the propulsion motor controller C9 is powered by the bus bar AR BUS or the bus bar BR BUS, and the fuse F9 is used as an overcurrent protection; the feeder transfer switch S11 controls whether the propulsion motor controller C11 is powered by the bus bar AR BUS or the bus bar BR BUS, and the fuse F11 is used as an overcurrent protection; the feeder transfer switch S2 controls whether the propulsion motor controller C2 is powered by the bus bar BR BUS or the bus bar AR BUS, and the fuse F2 is used as an overcurrent protection; the feeder transfer switch S8 controls whether the propulsion motor controller C8 is powered by the bus bar BR BUS or the bus bar AR BUS, and the fuse F8 is used as an overcurrent protection; the feeder transfer switch S12 controls whether the propulsion motor controller C12 is powered by the bus bar BR BUS or the bus bar AR BUS power supply, fuse F12 is used for overcurrent protection. Figure 2 shown.

[0117] 4) The power supply principle of each bus bar for each propulsion motor controller in each propulsion system is:

[0118] The propulsion motor controller C1 converts the high-voltage direct current provided by the bus bar into three-phase alternating current to power the propulsion motor M1; the propulsion motor controller C6 converts the high-voltage direct current provided by the bus bar into three-phase alternating current to power the propulsion motor M6; the propulsion motor controller C7 converts the high-voltage direct current provided by the bus bar into three-phase alternating current to power the propulsion motor M7; the propulsion motor controller C4 converts the high-voltage direct current provided by the bus bar into three-phase alternating current to power the propulsion motor M4; the propulsion motor controller C5 converts the high-voltage direct current provided by the bus bar into three-phase alternating current to power the propulsion motor M5; the propulsion motor controller C10 converts the high-voltage direct current provided by the bus bar into three-phase alternating current to power the propulsion motor M10; The propulsion motor controller C3 converts the high-voltage direct current provided by the bus bar into three-phase alternating current to power the propulsion motor M3; the propulsion motor controller C9 converts the high-voltage direct current provided by the bus bar into three-phase alternating current to power the propulsion motor M9; the propulsion motor controller C11 converts the high-voltage direct current provided by the bus bar into three-phase alternating current to power the propulsion motor M11; the propulsion motor controller C2 converts the high-voltage direct current provided by the bus bar into three-phase alternating current to power the propulsion motor M2; the propulsion motor controller C8 converts the high-voltage direct current provided by the bus bar into three-phase alternating current to power the propulsion motor M8; the propulsion motor controller C12 converts the high-voltage direct current provided by the bus bar into three-phase alternating current to power the propulsion motor M12. Figure 2 Shown

[0119] 5) Mechanical and driving relationships between propulsion motors and propellers in each propulsion system:

[0120] The propulsion motor M1 generates a pulling force by mechanically connecting the propeller P1; the propulsion motor M6 generates a pulling force by mechanically connecting the propeller P6; the propulsion motor M7 generates a pulling force by mechanically connecting the propeller P7; the propulsion motor M4 generates a pulling force by mechanically connecting the propeller P5; the propulsion motor M10 generates a pulling force by mechanically connecting the propeller P10; the propulsion motor M3 generates a pulling force by mechanically connecting the propeller P3; the propulsion motor M9 generates a pulling force by mechanically connecting the propeller P9; the propulsion motor M11 generates a pulling force by mechanically connecting the propeller P11; the propulsion motor M2 generates a pulling force by mechanically connecting the propeller P2; the propulsion motor M8 generates a pulling force by mechanically connecting the propeller P8; the propulsion motor M12 generates a pulling force by mechanically connecting the propeller P12. Figure 2 shown.

[0121] It should be noted that the redundancy design of the distributed electric propulsion system in the embodiment of the present invention is required to meet the system safety requirements, including the following requirements:

[0122] 1) A single battery pack has the ability to output 50% of the system's required power, which means that the normal output of any two battery packs can meet the system's maximum power requirement;

[0123] 2) The power stored in the four battery packs can meet the power demand of the aircraft for two flights, that is, the power stored in any two battery packs can meet the power demand of the aircraft for a single flight;

[0124] 3) The ability of a single propulsion motor to output 10% of the system power requirement when operating at rated status, that is, any 10 propulsion motors operating normally can meet the flight power requirement;

[0125] 4) It has the function of completing power supply conversion according to the status of the battery pack.

[0126] The power supply logic of the distributed electric propulsion system is shown in Table 1 below:

[0127] Table 1 Power supply logic table of distributed electric propulsion system

[0128]

[0129]

[0130] As shown in the power supply logic table 1 above, the distributed electric propulsion system in this specific implementation scheme has 16 power supply states and 64 power supply conversion modes, such as Figure 3 As shown, it is a schematic diagram of the power supply state conversion relationship of the distributed electric propulsion system in an embodiment of the present invention.

[0131] 1) State 1 <—> State 2;

[0132] 2) State 1 <—> State 3;

[0133] 3) State 1 <—> State 4;

[0134] 4) State 1 <—> State 5;

[0135] 5) State 2 <—> State 6;

[0136] 6) State 2 <—> State 7;

[0137] 7) State 2 <—> State 8;

[0138] 8) State 3 <—> State 6;

[0139] 9) State 3 <—> State 9;

[0140] 10) State 3 <—> State 10;

[0141] 11) State 4 <—> State 7;

[0142] 12) State 4 <—> State 9;

[0143] 13) State 4 <—> State 11;

[0144] 14) State 5 <—> State 8;

[0145] 15) State 5 <—> State 10;

[0146] 16) State 5 <—> State 11;

[0147] 17) State 6 <—> State 12;

[0148] 18) State 6 <—> State 13;

[0149] 19) State 7 <—> State 12;

[0150] 20) State 7 <—> State 14;

[0151] 21) State 8 <—> State 13;

[0152] 22) State 8 <—> State 14;

[0153] 23) State 9 <—> State 12;

[0154] 24) State 9 <—> State 15;

[0155] 25) State 10 <—> State 13;

[0156] 26) State 10 <—> State 15;

[0157] 27) State 11 <—> State 14;

[0158] 28) State 11 <—> State 15;

[0159] 29) State 12 <—> State 16;

[0160] 30) State 13 <—> State 16;

[0161] 31) State 14 <—> State 16;

[0162] 32)State 15<—>State 16.

[0163] for Figure 1 and Figure 2 For the distributed electric propulsion system shown in the figure, when the battery pack BAT, propulsion motor M, propulsion motor controller C and feeder fail, an unbalanced state of the battery pack output power may be caused. By adjusting the feeder conversion switches at the front end of each propulsion motor controller C, flexible power scheduling can be achieved, which can greatly reduce or even eliminate the imbalance of the battery pack output power.

[0164] The power balance control method of the distributed electric propulsion system provided by the embodiment of the present invention includes:

[0165] When a power-balanced distributed electric propulsion system fails so that the output power of the four battery packs is unbalanced, the fault location and type are detected; the fault location includes: at least one of the battery pack BAT, the propulsion motor M, the propulsion motor controller C, and the feeder fault;

[0166] According to the detected fault location and type, power supply conversion control is performed, and power balancing control is performed when the output power of the battery pack is unbalanced; the power balancing control method is: by adjusting the feeder conversion switch at the front end of the corresponding propulsion motor controller C, power scheduling between the bus bars is achieved to reduce or eliminate the output power imbalance of the battery pack.

[0167] It should be noted that in the embodiment of the present invention, the function of the conversion channel contactors BTC1 and BTC2 is power supply conversion control; the main function of the feeder transfer switches S1~S12 is battery pack power balance control, taking into account power supply conversion control (such as in the conversion control of power supply modes 8 and 9).

[0168] Figure 4 Flow chart of the power balance control method of the distributed electric propulsion system provided by the embodiment of the present invention. Figure 4 As shown, the power balance control method of the distributed electric propulsion system provided by the embodiment of the present invention specifically includes the following steps:

[0169] Step 1: Obtain the status of each component in the distributed electric propulsion system, including: battery pack, contactor, feeder transfer switch, propulsion motor, propulsion motor controller, feeder transfer switch fault conditions, and determine whether power supply conversion control needs to be executed according to the status of each component in the system;

[0170] Step 2: When the power supply status of each component in the system changes, the power supply conversion control of the system is completed according to the power supply mode (1 to 16) and the power supply conversion form of the system; that is, the above-mentioned 32*2 conversion forms.

[0171] Step 3: Detect the output status of the available battery pack and determine whether the output power of the battery pack is balanced;

[0172] Step 4: When the output power of the available battery groups is unbalanced, power balancing control is performed, including: by adjusting the feeder conversion switch, each available battery group can supply power to the same number of propulsion motor controllers as much as possible, so that the available battery groups achieve power balance; when the output power of the available battery groups is balanced, the power balancing control is skipped, and the status of each component in the system is updated, and a new round of power supply conversion control or power balancing control is performed.

[0173] In one implementation of an embodiment of the present invention, a method for implementing power balance control based on an ant colony algorithm is provided.

[0174] The objective function for designing a battery pack for distributed electric propulsion system power balance control to minimize the cost of powering the motor is:

[0175] The above formula is calculated for all available battery packs, and the number of motors powered by each battery pack may be different;

[0176] Among them, Cost i,j represents the cost of the i-th battery pack to perform the j-th task, N represents the total number of available battery packs, num i Represents the number of motors powered by the i-th battery pack.

[0177] Design the constraints for the above objective function, including:

[0178] 1) Battery pack load capacity constraint: Each available battery pack can only power up to 6 propulsion motors.

[0179] 1≤num i ≤6;

[0180] Among them, num i Indicates the number of motors powered by the i-th battery pack.

[0181] 2) Power balance constraint: To ensure power balance, the difference in the number of propulsion motors corresponding to each battery pack should not be greater than 1, that is:

[0182] num a -num b ≤1, a=(1,2,...,N), b=(1,2,...,N) and a≠b;

[0183] 3) Propulsion motor constraints: A propulsion motor can only be powered by one battery pack, that is:

[0184] And a≠b;

[0185] Among them, task a Represents the set of motors powered by the a-th battery pack. b Represents the set of motors powered by the bth battery pack.

[0186] 4) Constraints on the power supply capacity of the battery pack: Depending on the status of the conversion channel contactors (BTC1 and BTC2), the propulsion motors that the battery pack can power are different. The specific power supply capacity is:

[0187]

[0188] ability i It represents the ability of the i-th battery pack to supply power to 12 propulsion motors. 1 means that the battery pack can supply power to the motor, and 0 means that it cannot supply power. Ability1, Ability2, Ability3, and Ability4 represent BLBAT power supply capacity, AL BAT power supply capacity, AR BAT power supply capacity, and BR BAT power supply capacity, respectively.

[0189] 5) Limit the power supply cost of the propulsion motor:

[0190] Under different working conditions, the cost of each battery pack supplying power to each propulsion motor is as follows:

[0191]

[0192] Among them, Cost1, Cost2, Cost3, and Cost4 respectively represent: BL BAT is the motor power supply cost, AL BAT is the motor power supply cost, AR BAT is the motor power supply cost, and BR BAT is the motor power supply cost. When BTC2=0, it means that when BTC2 is disconnected, combined with the power supply capacity constraint of the battery pack, the battery pack provides the power supply cost for the motors it can power in order.

[0193] like Figure 5 As shown, it is an algorithm flow chart of the power balance control method in the power balance control method of the distributed electric propulsion system provided by the embodiment of the present invention. The method of implementing power balance control based on the ant colony algorithm includes the following steps:

[0194] Step 1: Collect the power supply status of each battery pack and each propulsion motor, and update the status of the battery pack and propulsion motor; the status in this step refers to the switching between 0 and 1.

[0195] Step 2: Initialize parameters: the number of available battery packs is N, the number of available propulsion motors is M, and the parameters related to the ant colony algorithm, such as the total number of ants is ant_num, the maximum number of iterations is NC_max, etc. Initialize the taboo table of each ant to be empty. The taboo table is used to record the propulsion motors that each ant has selected in the current path to prevent the ant from repeating the path.

[0196] It should be noted that in the ant colony algorithm, each ant seeks the path with the minimum cost. If it is empty, it means that the path has not been sought.

[0197] Step 3: Randomly select an unpowered available propulsion motor for ant k (selected from M propulsion motors), calculate the transfer probability, and select a propulsion motor that can be powered for the battery pack. The transfer probability calculation formula for the ant to transfer from the i-th available battery pack to the selected unpowered j-th propulsion motor is as follows:

[0198]

[0199] Among them, τ ij (t) represents the pheromone concentration value from the i-th battery pack to the j-th motor, η ij (t) is the heuristic function, and the inverse of the cost of the battery pack to power the motor is selected as the heuristic function. α is the pheromone heuristic factor, which indicates the importance of the pheromone left on the path passed by the ant. β is the expected heuristic factor, which indicates the importance of the heuristic information left by the ant when transferring the node. Allowed represents the set of nodes that have not been visited.

[0200] Step 4: Update the taboo table to record the propulsion motors that ant k has selected. Repeat step 3 until all ants have no propulsion motors to choose from, and then end the tour; that is, exit the loop from step 4 to step 3 and execute step 5.

[0201] Step 5: Determine whether the current power distribution meets the above constraints. If so, calculate the objective function value of the power distribution result for each ant and record the optimal power supply result for this iteration, that is, obtain the propulsion motor corresponding to each available battery pack, update the pheromone, and the specific pheromone update expression is shown in the following formula; otherwise, return to step 3. It should be noted that "optimal" means that the superposition cost of all available battery packs is the smallest.

[0202] τ ij (t+1)=(1-ρ)τ ij (t)+Δτ ijk (t+1);

[0203]

[0204] Among them, Δτ ijk (t) represents the amount of information left by the kth ant on the path in this cycle; Q is the pheromone intensity, which affects the convergence speed of the algorithm to a certain extent; L k Indicates the search length of the kth ant in this cycle.

[0205] Step 6: If the number of iterations NC reaches the maximum value NC_max, the optimal power supply result is output and the algorithm ends; otherwise NC=NC+1, and the algorithm returns to step 3.

[0206] The power balancing control method of a distributed electric propulsion system provided in an embodiment of the present invention is based on the system architecture of the distributed electric propulsion system. When a fault occurs in a power-balanced distributed electric propulsion system, causing the output power of four battery groups to be unbalanced, the fault location and type are detected; the fault location includes: battery group BAT, propulsion motor M, propulsion motor controller C, and at least one of the feeder faults; according to the detected fault location and type, power supply conversion control is performed, and power balancing control is performed when the output power of the battery group is unbalanced; wherein the power balancing control method is: by adjusting the feeder conversion switch at the front end of the corresponding propulsion motor controller C, electric energy scheduling between the bus bars is realized to reduce or eliminate the output power imbalance of the battery group. In the embodiment of the present invention, a feeder conversion switch is used between the propulsion motor controller and the bus bar, and a bus bar is selected for power supply through the feeder conversion switch to achieve control of the output power balance of the battery pack. Compared with the traditional power supply conversion control, the added power balance control scheme enables the electric propulsion system to achieve flexible power scheduling by adjusting the feeder conversion switches at the front end of each propulsion motor controller when a battery, propulsion motor, or controller fails, thereby significantly reducing or even eliminating the output power imbalance of the battery pack.

[0207] The implementation of the power balance control method of the distributed electric propulsion system provided by the embodiment of the present invention is described as follows through an implementation example:

[0208] Implementation examples;

[0209] This implementation example provides a power balance control method for a distributed electric propulsion system. A possible implementation example of the power balance control method is:

[0210] The layout diagram of each component on the aircraft is as follows Figure 1 shown.

[0211] Figure 2 This is a single-line diagram of the high-voltage DC propulsion system architecture of the distributed electric propulsion aircraft. The voltage of the battery packs BL BAT, AL BAT, AR BAT, and BR BAT is 450-660V, and the rated power of a single propulsion motor is 15kW.

[0212] The distributed electric propulsion system provided by the present invention has 16 power supply states, and there are 64 power supply conversion modes between the 16 power supply states, such as Figure 3 Shown is the power supply conversion diagram of the high-voltage direct current propulsion system of the distributed electric propulsion aircraft.

[0213] The above 16 power supply modes can be divided into 5 categories:

[0214] Category 1: Powered by 4 battery packs, serial number 16;

[0215] Category 2: Powered by 3 battery packs, serial numbers 12, 13, 14, 15;

[0216] Category 3: Powered by 2 battery groups: No. 6, 7, 8, 9, 10, 11; No. 6, 7, 10, 11 have similar control methods and can be divided into 1 group; No. 8, 9 have similar control methods and can be divided into 1 group;

[0217] Category 4: 1 battery pack for power supply: serial numbers 2, 3, 4, 5;

[0218] Category 5: Powered by 0 battery packs: Serial number 1.

[0219] The following example illustrates the power supply conversion control process:

[0220] (1) The system power supply conversion control process of sequence number 1->sequence number 2 is as follows Figure 6 As shown. First, initialize contactors BTC1 and BTC2 to the disconnected state. Then determine whether BR BAT is available. If not, return to power supply state 1 and wait for system status update; if available, close BRC. If the BR BUS is without power within the given delay time, mark the fault according to the BRC auxiliary contact state and return to power supply state 1; if the BR BUS is powered within the given delay time, close BTC2. If the BL BUS is powered within the given delay time, the power supply transfer is completed and the power supply state 2 is locked; if the BL BUS is without power within the given delay time, mark the fault according to the BTC2 auxiliary contact state, the power supply transfer is completed, and the power supply state 2 is locked.

[0221] (2) The system power supply conversion control process from sequence number 2 to sequence number 8 is as follows Figure 7 As shown. First, disconnect the contactor BTC2. If BTC2 cannot be disconnected within the given delay time, mark the BTC2 failure to disconnect and return to power supply state 2. If BTC2 is normally disconnected within the given delay time, control the feeder transfer switches S3, S9, and S11 to be powered by BR BUS and close BLC. On the one hand, after a fixed delay, mark the feeder transfer switch fault according to the power supply status of the propulsion motor controllers C3, C9, and C11; on the other hand, if the BL BUS has no power within the given delay time, mark the fault according to the BLC auxiliary contact status and return to power supply state 2; if the BL BUS has power within the given delay time, control the feeder transfer switches S4, S5, and S10 to be powered by BL BUS. After a fixed delay, mark the feeder transfer switch fault according to the power supply status of the propulsion motor controllers C4, C5, and C10. At this point, the power supply conversion is completed and the power supply state 6 is locked.

[0222] (3) The system power supply conversion control process of sequence number 16->sequence number 13 is as follows Figure 8As shown. First, disconnect the contactor ALC. If ALC cannot be disconnected within the given delay time, the ALC cannot be disconnected fault is marked and the state 16 is returned and locked. If ALC is disconnected within the given delay time, the contactor BTC1 is closed. If the AL BUS has power within the given delay time, the power supply conversion is completed and the power supply state 13 is locked; if the AL BUS has no power within the given delay time, the fault is marked according to the state of the BTC1 auxiliary contact, and then the feeder transfer switches S4, S5, and S10 are controlled to be powered by the BL BUS. After a fixed delay, the feeder transfer switch fault is marked according to the power supply status of the propulsion motor controllers C4, C5, and C10. At this point, the power supply conversion is completed and the power supply state 13 is locked.

[0223] (4) The system power supply conversion control process of sequence number 13->sequence number 6 is as follows Fig. 9 As shown. First, disconnect the contactor BLC. If the BL BUS still has power beyond the given delay time, mark the BLC unable to disconnect fault, return to power supply state 13 and lock the state; if the BL BUS has no power within the given delay time, close the contactor BTC2. If BTC2 is closed within the given time, the power supply transfer is completed and the power supply state 6 is locked; if BTC2 cannot be closed beyond the given delay time, mark the fault according to the BTC2 auxiliary contact state, the power supply transfer is completed, and the power supply state 6 is locked.

[0224] The following is an example of the power balance control method in this implementation example:

[0225] (1) Power supply state of sequence number 16, at this time all battery packs are available, and contactors BTC1 and BTC2 are disconnected. Assume that the system state at this time is as shown in the following table:

[0226]

[0227] According to the system power supply logic, the system power supply status at this time is: BL BAT supplies power to C1 through BL BUS; AL BAT supplies power to C4, C5 and C10 through AL BUS; AR BAT supplies power to C3, C9 and C11 through AR BUS; BR BAT supplies power to C2, C8 and C12 through BR BUS.

[0228] The present invention provides a power balance control method, and the control process is as follows:

[0229] Control the feeder transfer switch S4 so that C4 is powered by BL BUS;

[0230] Control other feeder transfer switches to their default states (control feeder transfer switch S1 so that C1 is powered by BL BUS; control feeder transfer switches S5 and S10 so that C5 and C10 are powered by AL BUS; control feeder transfer switches S3, S9 and S11 so that C3, C9 and C11 are powered by AR BUS; control feeder transfer switches S2, S8 and S12 so that C2, C8 and C12 are powered by BR BUS).

[0231] Finally, the system power supply status is: BL BAT supplies power to C1 and C4 through BL BUS; AL BAT supplies power to C5 and C10 through AL BUS; AR BAT supplies power to C3, C9 and C11 through AR BUS; BR BAT supplies power to C2, C8 and C12 through BR BUS. The output power of batteries BL BAT and AL BAT is balanced. The output power of batteries AR BAT and BR BAT is also in a balanced state.

[0232] (2) Power supply status of sequence number 13, at this time AL BAT is unavailable, contactor BTC1 is closed, and AR BAT supplies power to AL BUS. Assume that the system status at this time is as shown in the following table:

[0233]

[0234] According to the system power supply logic, the system power supply status at this time is: BL BAT supplies power to C1, C6 and C7 through BL BUS; AR BAT supplies power to C3, C9 and C11 through AR BUS, and AR BAT supplies power to AL BUS and C4, C5 and C10 through BTC1; BR BAT supplies power to C2, C8 and C12 through BR BUS.

[0235] Using the power balance control method provided by the present invention, the control process is:

[0236] Control the feeder transfer switch S4 so that C4 is powered by BL BUS;

[0237] Control the feeder transfer switch S11 so that C11 is powered by the BR BUS.

[0238] Control other feeder transfer switches to their default states (control feeder transfer switches S5 and S10 so that C5 and C10 are powered by AL BUS; control feeder transfer switches S3 and S9 so that C3 and C9 are powered by AR BUS).

[0239] Finally, the system power supply status is: BL BAT supplies power to C1, C4, C6 and C7 through BL BUS; AR BAT supplies power to C3 and C9 through ARBUS, and supplies power to C5 and C10 through AL BUS; BR BAT supplies power to C2, C8, C11 and C12 through BR BUS. The output power of the batteries BL BAT, AR BAT and BR BAT is balanced.

[0240] (3) The power supply state of sequence number 8, at this time, AL BAT and AR BAT are unavailable, contactors BTC1 and BTC2 are disconnected, and feeder transfer switches S4, S5 and S10 are controlled so that C4, C5 and C10 are powered by BL BUS, and feeder transfer switches S3, S9 and S11 are controlled so that C3, C9 and C11 are powered by BR BUS. At this time, the left and right channels form two independent power supply channels, which cannot dispatch electric energy to each other, and do not meet the conditions for carrying out power balance control. Similarly, the power supply state of sequence number 9 does not meet the conditions for carrying out power balance control.

[0241] (4) Power supply status of sequence number 6, at this time BL BAT and AL BAT are unavailable, contactors BTC1 and BTC2 are closed, AR BAT supplies power to AL BUS, and BR BAT supplies power to BL BUS. Assume that the system status at this time is as shown in the following table:

[0242]

[0243] According to the system power supply logic, the system power supply status at this time is: BR BAT supplies power to C2, C8 and C12 through BR BUS, and BR BAT supplies power to BL BUS and C1 through BTC2; AR BAT supplies power to C3, C9 and C11 through AR BUS, and ARBAT supplies power to AL BUS and C4, C5 and C10 through BTC1.

[0244] Using the power balance control method provided by the present invention, the control process is:

[0245] Control the feeder transfer switch S4 so that C4 is powered by BL BUS;

[0246] Control other feeder transfer switches to their default states (control feeder transfer switch S1 so that C1 is powered by BL BUS; control feeder transfer switches S5 and S10 so that C5 and C10 are powered by AL BUS; control feeder transfer switches S3, S9 and S11 so that C3, C9 and C11 are powered by AR BUS; control feeder transfer switches S2, S8 and S12 so that C2, C8 and C12 are powered by BR BUS).

[0247] BR BAT supplies power to C2, C8 and C12 through BR BUS, and BR BAT supplies power to C1 and C4 through BL BUS; ARBAT supplies power to C3, C9 and C11 through AR BUS, and AR BAT supplies power to C5 and C10 through AL BUS. The output power of the battery AR BAT and BR BAT is balanced.

[0248] Although the embodiments disclosed in the present invention are as above, the contents are only embodiments adopted to facilitate understanding of the present invention and are not intended to limit the present invention. Any technician in the field to which the present invention belongs can make any modifications and changes in the form and details of implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A power balance control method for a distributed electric propulsion system, characterized in that: The distributed electric propulsion system comprises: a left A channel (AL) and a right A channel (AR) symmetrically distributed on both sides of the distributed electric propulsion aircraft, and a left B channel (BL) and a right B channel (BR) symmetrically distributed, wherein the A channel is located inside the B channel, and the four channels include four bus bars (BLBUS, AL BUS, AR BUS, BR BUS), four battery packs (BL BAT, AL BAT, AR BAT, BR BAT), 4 main channel contactors (BLC, ALC, ARC, BR), 2 conversion channel contactors (BTC1, BTC2), 4n feeder transfer switches, 4n fuses, 4n propulsion motor controllers, 4n propulsion motors, 4n circuit breakers and 4n propellers, and a system control unit, wherein n is a positive integer greater than or equal to 1; wherein the battery pack in each channel is connected to the bus bar through a main channel contactor, the bus bar is powered by the battery pack, and the on-off state of the battery pack and the bus bar in each channel is controlled by the main channel contactor; the bus bar AL BUS of the left channel A and the bus bar AR BUS of the right channel A are connected through the conversion channel contactor BTC1, and the bus bar BL BUS of the left channel B and the bus bar BR of the right channel B are connected through the conversion channel contactor BTC1. The BUS is connected through a conversion channel contactor BTC2, and each conversion channel contactor controls the on-off state between the two end buses connected thereto; in the left A channel (AL) and the left B channel (BL), each propulsion motor controller is selectively powered by BLBUS or AL BUS through a feeder conversion switch, and in the right A channel (AR) and the right B channel (BR), each propulsion motor controller is selectively powered by AR BUS or BR BUS through a feeder conversion switch, and a fuse for overcurrent protection is connected between the propulsion motor controller and the feeder conversion switch; the system control unit is respectively connected to each battery pack, each bus bar, each main channel contactor, each conversion channel contactor, and each feeder conversion switch; The power balance control method of the distributed electric propulsion system includes: When a power-balanced distributed electric propulsion system fails so that the output power of the four battery packs is unbalanced, the fault location and type are detected; the fault location includes: at least one of the battery pack BAT, the propulsion motor M, the propulsion motor controller C, and the feeder fault; According to the detected fault location and type, power supply conversion control is performed, and power balancing control is performed when the output power of the battery pack is unbalanced; the power balancing control method is: by adjusting the feeder conversion switch at the front end of the corresponding propulsion motor controller C, power scheduling between the bus bars is achieved to reduce or eliminate the output power imbalance of the battery pack.

2. The power balance control method of a distributed electric propulsion system according to claim 1, characterized in that: The power balance control method comprises: Step 1, obtaining the status of each component in the distributed electric propulsion system, including: the battery pack, the contactor, the feeder transfer switch, the propulsion motor, the propulsion motor controller, and the fault status of the feeder transfer switch, and determining whether power supply conversion control needs to be executed according to the status of each component in the system; Step 2: When the power supply status of each component in the system changes, the power supply conversion control of the system is completed according to the power supply mode and power supply conversion form of the system; Step 3, detecting the output status of the available battery packs and determining whether the output power of the battery packs is balanced; Step 4, when it is determined in step 3 that the output power of the available battery packs is unbalanced, power balancing control is performed, including: by adjusting the feeder conversion switch, each available battery pack supplies power to the same number of propulsion motor controllers as much as possible, so that the available battery packs achieve power balance; when it is determined in step 3 that the output power of the available battery packs is balanced, power balancing control is skipped, and the status of each component in the system is updated, and a new round of power supply conversion control or power balancing control is performed.

3. The power balance control method of a distributed electric propulsion system according to claim 2, characterized in that: In the distributed electric propulsion system, the battery pack BL BAT is connected to the bus bar BL BUS via the main channel contactor BLC; the battery pack AL BAT is connected to the bus bar AL BUS via the main channel contactor ALC; the battery pack AR BAT is connected to the bus bar AR BUS via the main channel contactor ARC; the battery pack BR ​​BAT is connected to the bus bar BR BUS via the main channel contactor BRC; In the distributed electric propulsion system, the feeder conversion switch S1 controls whether the propulsion motor controller C1 is powered by the bus BLBUS or the bus AL BUS; the feeder conversion switch S7 controls whether the propulsion motor controller C7 is powered by the bus BL BUS or the bus AL BUS; the feeder conversion switch S6 controls whether the propulsion motor controller C6 is powered by the bus BL BUS or the bus AL BUS; the feeder conversion switch S4 controls whether the propulsion motor controller C4 is powered by the bus AL BUS or the bus BL BUS; the feeder conversion switch S10 controls whether the propulsion motor controller C10 is powered by the bus AL BUS or the bus BL BUS; the feeder conversion switch S5 controls whether the propulsion motor controller C5 is powered by the bus AL BUS or the bus BL BUS; the feeder conversion switch S3 controls whether the propulsion motor controller C3 is powered by the bus AR BUS or the bus BR BUS; the feeder conversion switch S9 controls whether the propulsion motor controller C9 is powered by the bus AR BUS The feeder conversion switch S11 controls whether the propulsion motor controller C11 is powered by the bus bar AR BUS or the bus bar BR BUS; the feeder conversion switch S2 controls whether the propulsion motor controller C2 is powered by the bus bar BR BUS or the bus bar AR BUS; the feeder conversion switch S8 controls whether the propulsion motor controller C8 is powered by the bus bar BR BUS or the bus bar AR BUS; the feeder conversion switch S12 controls whether the propulsion motor controller C12 is powered by the bus bar BR BUS or the bus bar AR BUS.

4. The power balance control method of a distributed electric propulsion system according to claim 3, characterized in that: The status information of the four battery packs, and the on / off status of the corresponding four main channel contactors and two conversion channel contactors, form 16 power supply states of the distributed electric propulsion system and 64 power supply conversion modes; The power supply logic table of the distributed electric propulsion system is: The 64 power supply conversion modes include the following bidirectional conversions: 1) State 1 <—> State 2; 2) State 1 <—> State 3; 3) State 1 <—> State 4; 4) State 1 <—> State 5; 5) State 2 <—> State 6; 6) State 2 <—> State 7; 7) State 2 <—> State 8; 8) State 3 <—> State 6; 9) State 3 <—> State 9; 10) State 3 <—> State 10; 11) State 4 <—> State 7; 12) State 4 <—> State 9; 13) State 4 <—> State 11; 14) State 5 <—> State 8; 15) State 5 <—> State 10; 16) State 5 <—> State 11; 17) State 6 <—> State 12; 18) State 6 <—> State 13; 19) State 7 <—> State 12; 20) State 7 <—> State 14; 21) State 8 <—> State 13; 22) State 8 <—> State 14; 23) State 9 <—> State 12; 24) State 9 <—> State 15; 25) State 10 <—> State 13; 26) State 10 <—> State 15; 27) State 11 <—> State 14; 28) State 11 <—> State 15; 29) State 12 <—> State 16; 30) State 13 <—> State 16; 31) State 14 <—> State 16; 32)State 15<—>State 16.

5. The power balance control method of a distributed electric propulsion system according to claim 4, characterized in that: In step 4, the distributed electric propulsion system performs power balance control by using an ant colony algorithm, and the ant colony algorithm design method includes: S1, the objective function for designing the battery pack for power balance control of distributed electric propulsion system to minimize the cost of powering the motor is: Among them, Cost i,j represents the cost of the i-th battery pack to perform the j-th task, N represents the total number of available battery packs, num i Represents the number of motors powered by the i-th battery pack. S2, determine the constraints of the objective function, including: battery pack load capacity constraints, power balance constraints, and propulsion motor constraints.

6. The power balance control method of a distributed electric propulsion system according to claim 5, characterized in that: The constraints in S2 are: 1) Battery pack load capacity constraint: Each available battery pack can only power up to 6 propulsion motors, that is, 1≤num i ≤6; Among them, num i Indicates the number of motors powered by the i-th battery pack. 2) Power balance constraint: To ensure power balance, the difference in the number of propulsion motors corresponding to each battery pack should not be greater than 1, that is: num a -num b ≤ 1, a = (1, 2,..., N), b = (1, 2,..., N) and a ≠ b; 3) Propulsion motor constraints: A propulsion motor can only be powered by one battery pack, that is: a=(1,2,...,N),b=(1,2,...,N) and a≠b; Among them, task a Represents the set of motors powered by the ath battery pack. b represents the set of motors powered by the bth battery pack; 4) Constraints on the power supply capacity of the battery pack: Based on the different states of the two conversion channel contactors, the power supply capacity of each battery pack to each propulsion motor is obtained as follows: ability i Indicates the ability of the i-th battery pack to supply power to the 12 propulsion motors. 1 indicates that the battery pack can supply power to the motor, and 0 indicates that it cannot supply power. Ability1, Ability2, Ability3, and Ability4 represent BL BAT power supply capability, AL BAT power supply capability, AR BAT power supply capability, and BR BAT power supply capability, respectively. 5) Limit the power supply cost of the propulsion motor: Under different working conditions, the cost of each battery pack supplying power to each propulsion motor is as follows: Among them, Cost1, Cost2, Cost3, and Cost4 respectively represent: BL BAT is the motor power supply cost, AL BAT is the motor power supply cost, AR BAT is the motor power supply cost, and BR BAT is the motor power supply cost. When BTC2=0, it means that when BTC2 is disconnected, combined with the power supply capacity constraint of the battery pack, the battery pack provides the power supply cost for the motors it can power in order.

7. The power balance control method of a distributed electric propulsion system according to claim 6, characterized in that: The methods of realizing power balance control based on the designed ant colony algorithm include: Step 51, collecting the power supply status of each battery pack and each propulsion motor, and updating the status of the battery pack and the propulsion motor; Step 52, initializing parameters: the number of available battery packs is N, the number of available propulsion motors is M, and the parameters related to the ant colony algorithm, such as the total number of ants is ant_num, and the maximum number of iterations is NC_max; initializing the taboo table of each ant to be empty, the taboo table is used to record the propulsion motors that each ant has selected in the current path, so as to avoid the ant from repeating the path; Step 53, randomly selecting an unpowered available propulsion motor for ant k from the M propulsion motors, calculating the transfer probability, and selecting a propulsion motor that can be powered for the battery pack; Step 54, update the taboo table to record the propulsion motors that ant k has selected. Repeat step 3 until all ants have no propulsion motors to choose from, and then end the tour; that is, exit the loop of step 54 and step 53, and execute step 55; Step 55, determine whether the current power distribution satisfies the above constraints. If so, calculate the objective function value of the power distribution result of each ant and record the optimal power supply result of this iteration, that is, obtain the propulsion motor corresponding to each available battery pack, and update the pheromone. The specific pheromone update expression is shown in the following formula; otherwise, return to step 53; Step 56: If the number of iterations NC reaches the maximum value NC_max, the optimal power supply result is output and the algorithm ends; otherwise, NC=NC+1, and the process returns to step 3.

8. The power balance control method of a distributed electric propulsion system according to claim 7, characterized in that: In step 53, the calculation formula for calculating the transfer probability of the ant from the i-th available battery pack to the selected j-th propulsion motor that is not powered is as follows: Among them, τ ij (t) represents the pheromone concentration value from the i-th battery pack to the j-th motor, η ij (t) is the heuristic function, and the inverse of the cost of the battery pack to power the motor is selected as the heuristic function. α is the pheromone heuristic factor, which indicates the importance of the pheromone left on the path passed by the ant. β is the expected heuristic factor, which indicates the importance of the heuristic information left by the ant when transferring the node. Allowed represents the set of nodes that have not been visited.

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