A turbocharger for a supercharged internal combustion engine; the turbocharger has: a turbine, which is provided with a shaft mounted in a rotatory manner; a compressor, which is provided with a shaft mounted in a rotatory manner and is mechanically independent from the shaft of the turbine; and a single electrical machine, which is interposed between the turbine and the compressor, and is provided with a first rotor, which is mechanically connected to the shaft of the turbine, and with a second rotor which is mechanically connected to the shaft of the compressor to work as an electromagnetic joint between the shaft of the turbine and the shaft of the compressor.