Limit Cycles Bifurcations for a Class of 3-Dimensional Quadratic Systems

Our work is concerned with the Hopf bifurcation for a class of 3-dimensional quadratic symmetric vector field. By making use of singular values methods and computing carefully, we give the expressions of the first four focal values of the two singular point that system has. Both singular symmetric points can become fine foci of fourth order at the same time. Moreover, we obtain that from each one can bifurcate 4 small limit cycles under a certain coefficients’ perturbed condition, consequently, at most eight limit cycles can appear by simultaneous Hopf bifurcation.