hi gill i like your work. i've only just started looking in to this it's very interesting. i just wanted to message regarding the harmonic frequencies. you do not need to create them they are created automatically as an effect of connecting a load to an alternating current you get frequencies develop that are multiples of the original frequency so if the original is 30khz you'll get 3x30khz 90khz
9x30khz 270khz and so on its quite in depth. perhaps research "harmonics in electrical power"