A device for generating an alternating radio-frequency electromagnetic field in a working area includes an applicator emitting the electromagnetic field, an oscillator providing an alternate voltage and electric current having a predetermined value and a predetermined frequency to the applicator, a power supply supplying a substantially DC voltage to the oscillator, and a control system controlling the electrical parameters of the AC voltage, the AC current and/or the frequency provided to the applicator by the oscillator. The control system includes an input port connected to the electric power network, a first electronic control connected to the input port and substantially instantaneously varying the electrical parameters and instantaneous control of the field emission power, and a second electronic control circuit regulating the operation of the oscillator. The first electronic circuit has an output connected to the power supply. A plant includes the device and a control method for the device.
