The entire circuit of the frequency converter consists of AC to DC to AC to filtering sections, hence it outputs pure sine wave voltages and currents, closely resembling an ideal AC power supply. It can produce any grid voltage and frequency worldwide.
The inverter is composed of circuits such as AC-to-DC-to-AC (modulated wave). The standard name for the inverter should be variable frequency speed controller. Its output voltage waveform is a pulse square wave, with a high harmonic content. The voltage and frequency change proportionally at the same time, and cannot be adjusted separately, which does not meet the requirements of AC power sources. In principle, it cannot be used as a power supply source and is generally only used for the speed regulation of three-phase asynchronous motors. 400Hz power supply
