This chapter presents control methods applied in the operation of the series loaded series resonant (SLSR) power converters in a most efficient operation zone. The choice of the control method is affected by the objective to guarantee suitably the efficiency, being this method in the same time, relatively easy to apply. The first part of the chapter compares three basic principles of regulation: frequency mode (FM), pulse width mode (PWM), and their combination (PWM/FM). Finally, a new method for instantaneous regulation is developed. The proposed technique consists of a simplified observation of a state variable value to limit each portion of supplied energy, depending on the requirement for power in each half period. The result of this regulation is comparable to the current mode (CM) control applied to the hard-switching power converters. The viability of this new regulation method is demonstrated by simulations of its analogue circuit implementations and experimentally proved. The circuit is also prepared for the changes in the magnetic coupling (contactless energy transfer).