| CPC H02J 1/08 (2013.01) [B64D 47/00 (2013.01); B64D 2221/00 (2013.01); H02J 2203/20 (2020.01)] | 5 Claims |
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1. A distributed optimization control method for an aircraft energy system considering loss, comprising the following steps:
S1, based on characteristics of an actual near-space aircraft energy system and a near-space environment, establishing a multi-bus direct current (DC) microgrid system model for the actual near-space aircraft energy system according to Kirchhoff's law; and according to an input voltage and current data and an output voltage and current data of the actual near-space aircraft energy system, fitting a functional relationship between a loss power of a DC/DC converter and an output current of the actual near-space aircraft energy system, as shown in the following:
I−ID=GeV
IL=WeMeV
wherein V is a bus voltage, I is an output current of the DC/DC converter, ID is a load current, IL is a line current, Ge is a node conductance matrix, Me is a correlation matrix corresponding to an electrical network, elements of Me are −1, 0, 1, We is a diagonal coefficient matrix, and a diagonal element of We is an electrical transmission line conductance at a corresponding position of the correlation matrix;
S2, according to an energy scheduling requirement of the actual near-space aircraft energy system, establishing a system control target as follows:
 wherein Vi(t) is a bus voltage at time t, Ii(t) is an output current of the DC/DC converter at the time t, and Viref is a reference value of a bus voltage of an optical storage node i of the actual near-space aircraft energy system; and mi is a proportional coefficient of a current distribution;
the actual near-space aircraft energy system satisfies the following electrical inequality constraints:
 wherein V and V are an upper limit and a lower limit of the bus voltage, I and Ī are an upper limit and a lower limit of the output current of the DC/DC converter, IL is the line current, and IL is an upper limit of the line current;
a total loss of the DC/DC converter of an entire aircraft energy system PLossC is in a form of the following:
 wherein ai is a secondary loss coefficient of the DC/DC converter in the optical storage node i, bi is a primary loss coefficient of the DC/DC converter in the optical storage node i, ci is a loss constant term of the DC/DC converter in the optical storage node i; 1N=[1,1, . . . ,1]T is a unit column vector composed of N elements, and A=diag([a1, a2, . . . , aN]), b=[b1, b2, . . . , bN]T and c=[c1, c2, . . . , cN]T are loss coefficients of the DC/DC converter;
a total line loss of the entire aircraft energy system PLossL is as follows:
 wherein an operating loss o the entire near-space aircraft energy system is as follows:
PLoss=PLossC+PLossL
S3, according to the system control target, establishing an optimal scheduling problem of an aircraft energy system considering the operating loss as follows:
 wherein w1, w2, μ1, μ2>0 are weight coefficients of the system control target, and μ1+μ2=1; a current distribution error is Δl=(MGV+QID)T(MGV+QID), wherein
 and (⋅)T are transposed operations; and a voltage regulation error ΔV meets ΔV=(V−Vref)T(V−Vref), Vref=[V1ref, V2ref, . . . , VNref]T;
S4, based on a projection and a penalty, designing a distributed optimization control algorithm as follows:
 wherein
 (⋅) is a projection on a convex set ΩVi={Vi|Vi≤Vi≤Vl}, ∇(⋅) is a first derivative of a decision variable, sign(⋅) is a sign function, Ni is a set of neighbor nodes, wherein the neighbor nodes communicate directly with a local controller of the optical storage node i of the actual near-space aircraft energy system, IDi is a local load current of the optical storage node i of the actual near-space aircraft energy system, k1, k2, k>0 are controller gains, and αi, βi, γi, θij are controller auxiliary variables;wherein a penalty function ψ(x) is in a form of the following:
 wherein δ≥0 needs to be adjusted according to an actual operation.
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