All the four ways of converting the parameters of electric energy: AC/AC, AC/DC, DC/DC, DC/AC may be regarded within the scope of common direct frequency conversion process, that is, as separate its modes, depending on the value of modulating frequency. Such a common process, for example, at zero value output frequency corresponds to the formation of different levles of the direct current, but the inverter mode is modelled by forming the output voltage from the direct current levels mentioned with the value variation of the modulating function. That new approach to the direct frequency common process analysis allows one to evolve new theoretical ideas concerning the generalisation of electric energy conversion and, consequently, on the basis of this generalisation, to create new conversion methods.