The utility model discloses a broad width pressure regulating subassembly that frequency transformer keeps apart, including first converter, second converter and power frequency isolation transformer, input voltage inserts power frequency isolation transformer's high -pressure side winding, power frequency isolation transformer's low tension side winding is respectively with first, the second converter is connected, the first output of first converter is as output voltage's one end, the second output of first converter and the second output of second converter are connected, the first output of second converter is as output voltage's the other end, input voltage US and offset voltage UC1, UC2 carries out the vector stack, produce output voltage U0. The utility model discloses contactless, stepless, the sinusoidal wave power electronic voltage regulator of broad width, the stabiliser that have that frequency transformer keeps apart, be applicable to single, the three -phase system of different capacity grades, high performance -price ratio, etc.