An inverter power supply that undergoes AC→DC→AC conversion is known as a variable frequency power supply. It differs from the variable frequency speed control used for motor speed regulation and also from the standard AC voltage regulator. The primary function of a variable frequency power supply is to convert the existing AC grid power into a stable, pure sine wave power supply at the required frequency. Ideal AC power is characterized by stable frequency, stable voltage, zero internal resistance, and a pure sine wave voltage waveform (no distortion). Variable frequency power supplies are very close to ideal AC power, which is why more and more advanced and developed countries are using them as standard power supplies to provide a good power supply environment for electrical appliances and facilitate objective evaluation of their technical performance.
