According to the method of controlling a switching converter of this disclosure, the following operations are carried out: :
regulation of the output power to be delivered to the at least one resonant load is obtained adjusting the common switching frequency of all said PWM control signals and the phase displacement of all said PWM control signals, wherein said step of adjusting the phase displacement is carried out by adjusting a time delay between the turning-on of diagonal switches of said two half-bridge switching stages connecting said resonant load, within the same switching period. The phase displacement is carried out until hard-switching working conditions for said half-bridge switching stages are met, and wherein when said hard switching working conditions are met the method further comprises the step of adjusting the common switching frequency of all said PWM control signals to thereby prevent hard-switching working conditions.
The control method of this disclosure is particularly suitable for being used in multi-stage inverters according to this disclosure, comprising more than three half-bridge switching stages.