Circuit, fan system, and transformer for power conversion

A fan system, comprising:

• a gas inlet portion configured to introduce an external gas;
• a plasma generation device, which is configured to generate plasma and an electric field for driving the plasma to make a directional movement, such that the external gas introduced from the gas inlet portion makes a directional movement following the plasma, wherein the plasma generation device is configured to be driven by a circuit, or the plasma generation device is configured to receive an output signal with superimposed direct current and alternating current output by the circuit;
• and
• a gas purifying unit, which is configured to purify the external gas passing through the plasma generation device to reduce a concentration of ozone ions in the external gas.

A transformer, comprising:

• a core;
• a primary coil wound around the core;
• an electrical insulating skeleton provided with a plurality of grooves in a direction perpendicular to an axis of the core;
• and
• secondary coils sequentially wound in series in each of the plurality of grooves.