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⛄ 内容介绍
为了提高短期光伏发电预测的准确性,文中采用深度置信网络(DBN)建立了各模型函数的预测模型.通过分析各模型函数的特征,建立了光伏发电模型的功率预测.传统的基于神经网络的功率预测难以训练多层网络,影响其预测精度.DBN采用无监督贪婪逐层训练算法构建了一个在回归预测分析中具有优异性能的多隐层网络结构,已成为深度学习领域的研究热点.DBN参数采用麻雀优化算法(SSA)优化,避免出现由随机初始化导致的局部最优解现象,从而提高了DBN网络预测性能.最后,案例测试显示了所提出模型的有效性.
⛄ 部分代码
function [fMin , bestX, Convergence_curve] = SSA(X, N, M, c, d, dim, fobj)
P_percent = 0.2; % 发现者的种群规模占总种群规模的百分比
pNum = round(N*P_percent); % 发现者数量20%
SD = pNum/2; % 警戒者数量10%
ST = 0.8; % 安全阈值
lb = c.*ones(1, dim); % 下限
ub = d.*ones(1,dim); % 上限
% 初始化
for i = 1:N
% X(i, :) = lb + (ub - lb) .* rand(1, dim);
fitness(i) = fobj(X(i, :));
end
pFit = fitness;
pX = X; % 与pFit相对应的个体最佳位置
[fMin, bestI] = min(fitness); % fMin表示全局最优解
bestX = X(bestI, :); % bestX表示全局最优位置
%% 迭代寻优
for t = 1 : M
[~, sortIndex] = sort(pFit); % 排序
[fmax, B] = max(pFit);
worst = X(B, :);
%% 发现者位置更新
r2 = rand(1);
if r2 < ST
for i = 1:pNum % Equation (3)
r1 = rand(1);
X(sortIndex(i), :) = pX(sortIndex(i), :)*exp(-(i)/(r1*M));
X(sortIndex(i), :) = Bounds(X(sortIndex(i), :), lb, ub);
fitness(sortIndex(i)) = fobj(X(sortIndex(i), :));
end
else
for i = 1:pNum
X(sortIndex(i), :) = pX(sortIndex(i), :)+randn(1)*ones(1, dim);
X(sortIndex(i), :) = Bounds(X(sortIndex(i), :), lb, ub);
fitness(sortIndex(i)) = fobj(X(sortIndex(i), :));
end
end
[~, bestII] = min(fitness);
bestXX = X(bestII, :);
%% 跟随者位置更新
for i = (pNum+1):N % Equation (4)
A = floor(rand(1, dim)*2)*2-1;
if i > N/2
X(sortIndex(i), :) = randn(1)*exp((worst-pX(sortIndex(i), :))/(i)^2);
else
X(sortIndex(i), :) = bestXX+(abs((pX(sortIndex(i), :)-bestXX)))*(A'*(A*A')^(-1))*ones(1, dim);
end
X(sortIndex(i), :) = Bounds(X(sortIndex(i), :), lb, ub);
fitness(sortIndex(i)) = fobj(X(sortIndex(i), :));
end
%% 警戒者位置更新
c = randperm(numel(sortIndex));
b = sortIndex(c(1:SD));
for j = 1:length(b) % Equation (5)
if pFit(sortIndex(b(j))) > fMin
X(sortIndex(b(j)), :) = bestX+(randn(1, dim)).*(abs((pX(sortIndex(b(j)), :) -bestX)));
else
X(sortIndex(b(j)), :) = pX(sortIndex(b(j)), :)+(2*rand(1)-1)*(abs(pX(sortIndex(b(j)), :)-worst))/(pFit(sortIndex(b(j)))-fmax+1e-50);
end
X(sortIndex(b(j)), :) = Bounds(X(sortIndex(b(j)), :), lb, ub);
fitness(sortIndex(b(j))) = fobj(X(sortIndex(b(j)), :));
end
for i = 1:N
% 更新个体最优
if fitness(i) < pFit(i)
pFit(i) = fitness(i);
pX(i, :) = X(i, :);
end
% 更新全局最优
if pFit(i) < fMin
fMin = pFit(i);
bestX = pX(i, :);
end
end
Convergence_curve(t) = fMin;
disp(['SSA: At iteration ', num2str(t), ' ,the best fitness is ', num2str(fMin)]);
end
%% 边界处理
function s = Bounds(s, Lb, Ub)
% 下界
temp = s;
I = temp < Lb;
temp(I) = Lb(I);
% 上界
J = temp > Ub;
temp(J) = Ub(J);
% 更新
s = temp;
⛄ 运行结果
⛄ 参考文献
[1]吴涛. 基于PSO优化VMD和深度信念网络的滚动轴承故障诊断研究.
[2]王新颖, 赵斌, 张瑞程,等. 基于IPSO-DBN的管道故障诊断方法[J]. 消防科学与技术, 2021, 040(002):263-267.
