Apparatus and associated methods involve a controllable supply adapted for controlling switch phasing and pulse width to substantially equalize power in adjacent quadrants of a sinusoidal source voltage waveform to regulate reactive power drawn from the source. In an illustrative example, the supply may, in some embodiments, deliver power to a load at a level responsive to a commanded input signal. In some examples, the power supplied to the load may be adjusted according to the command input signal to a selected value within an operating range. In some examples, the operating range may include a portion or all of 0 to 100% of rated load. Various embodiments may be adapted to supply unipolar or bipolar load excitation. In some embodiments, high power factor may be maintained over a substantial range of commanded power to the load. Certain embodiments may enhance supply efficiency by capturing and recycling inductive load energy.