Aircraft electrical systems use a three-phase, 400 HZ, AC Bus supplied by engine driven generators. In an effort to simplify and improve the production of AC power for aircraft and to eliminate the need for hydromechanical constant-speed drive (CSD), a number of systems have been devised for producing 400 HZ three-phase electric power using electronic circuitry. This has been made possible by some of the major advances in solid-state technology developed in recent years. One of these systems is a DC-Link converter, which has a variable input frequency but a constant output frequency. This offer a viable alternative to the CSD as means of providing a constant frequency power supply from an aircraft generator. The ease of replacement and repair, the reduction in servicing needs, and the ability to locate the components of the electrical systems through the aircraft all combine to bring about a considerable reduction in the maintenance time required. This thesis discusses aircraft generating systems, variable speed constant frequency systems (VSCF) and the principle of the static frequency converter. The operation and design of a 1 KVA three-phase PWM inverter and its associated control circuitry to produce 400 HZ AC is described in detail. Finally a design of a power harmonic filter is given.