dde23 integration time and step size problems

I am trying to solve solve this delayed equation system using dde23.

H1=x(1);
H11=x(2);
%H1
y(1)=k1*(1+(Z1(2)/q11)^(N))^(-1)-c1*H1- 2*a11*(H1)^2+2*b11*H11;
%H11
y(2) =a11*H1*H1-b11*H11-c11*H11;

This type of system produce oscillations in H1 and H11. The problem is that under certain conditions (the parameter "b11" very big) it takes almost infinit time to solve the equation. The step size of the solver becomes smaller and smaller but the solver never reaches to an end and stop integration.

I tried to set de abstol and reltol in very low values but this doesnt improoves very much the integration time.

Is there a way that I can limitate the minstep size? Or a way to improve the code so that the solver could integrate the system?

Thank you very much.