  We analyze electron dynamics and topological properties of open double
quantum dots (DQDs) driven by circularly polarized ac-magnetic fields. In
particular we focus on the system symmetries which can be tuned by the
ac-magnetic field. Remarkably, we show that in the electron spin resonance
(ESR) configuration, where the magnetic fields in each dot oscillate with a
phase difference of $\pi$, charge localization occurs giving rise to transport
blocking at arbitrary intensities of the ac field. The conditions for charge
localization are obtained by means of Floquet theory and related with
quasienergies degeneracy. We also demonstrate that a topological phase
transition can be induced in the adiabatic regime for a phase difference of
$\pi$, either by tuning the coupling between dots or by modifying the intensity
of the driving magnetic field.
