There are inverters on the market which take the incoming power, rectify it to produce DC, then use switching techniques to convert the DC into a pulse-width modulated AC signal of the desired frequency, which can then be filtered to get a smoother sine wave. Inverters are available in all sizes (depending on line voltage, output power capacity, etc.) from a wide variety of manufacturers.<br>If your 50 Hz power is driving a motor, use a variable speed drive.
