Power control apparatus and method

A method of modulating a respective second signal in each of a second secondary winding and a third secondary winding of a power control apparatus having a magnetic core comprising a first limb, a second limb, and a third limb, wherein the first limb, the second limb and the third limb are each arc-shaped limbs, wherein each limb is arranged around a central axis, and each limb has a first end and a second end, wherein the first ends of the limbs are mutually connected at a first position along the central axis, and the second end of the limbs are mutually connected at a second position along the central axis, wherein a primary winding is arranged around the first limb, the primary winding is electrically coupled to a first AC power supply having a first phase and the first AC power supply induces a first signal in the primary winding, the second secondary winding is arranged around the second limb, and the third secondary winding is arranged around the third limb, the second secondary winding is electrically coupled to a second load, the third secondary winding is electrically coupled to a third load, the power control apparatus further having a first voltage source converter having an AC connection and a DC connection, and a second voltage source converter having an AC connection and a DC connection, wherein either the AC connection of the first voltage source converter is electrically coupled to the primary winding, or the power control apparatus comprises a modulation winding arranged around the first limb and the AC connection of the first voltage source converter is electrically coupled to the modulation winding arranged around the first limb, and wherein either the AC connection of the second voltage source converter is electrically coupled to each of the second secondary winding and the third secondary winding, or the power control apparatus comprises a respective modulation winding arranged around each of the second and third limb and the AC connection of the second voltage source converter is electrically coupled to each of the modulation windings arranged around each of the second and third limbs,

• the method comprising:
• receiving data associated with parameters of a first signal in the primary winding;
• comparing the parameters of the first signal to parameters of a respective reference signal for each of the second secondary winding and the third secondary winding;
• determining a harmonisation signal which, when applied to the first limb, causes the respective second signal in each of the second secondary winding and the third secondary winding to approximate the respective reference signal;
• and
• causing application of the harmonisation signal to the first limb using the first voltage source converter.