This document discusses strategies for eliminating harmonics in inverter AC power supplies. It begins by defining harmonics as frequencies that are integer multiples of the fundamental power system frequency, which are generated by non-linear loads. Several harmonic elimination strategies are described, including passive filters, line reactors, isolation transformers, transformer connections, and pulse width modulation techniques. Pulse width modulation can minimize specific harmonics by controlling the pulse width and number. Higher pulse numbers can eliminate more harmonics. The document concludes that eliminating harmonics is important to protect electronic devices and equipment from failures caused by harmonic distortion.