Control of a high-frequency rectifier

The quality of the electricity supply can be affected by the operation of power conversion equipment such as ac/dc rectifiers and ac/dc/ac converters. Power conversion equipment such as this is widely used in industrial, commercial and domestic applications and the number of applications that use power conversion equipment is rapidly increasing. The conventional power conversion systems that are implemented have been developed to supply the required waveform to the load without regard for the effect that this has on the supply. The operation of these systems can produce a large number of harmonics on the supply, which reduces the quality of the supply and causes problems such as an increase in losses and inefficient operation. Developments in power conversion equipment have included the introduction of conversion equipment which is capable of operating at high switching frequencies. This type of system can be operated in such a way as to produce minimal supply distortion. This thesis considers one such system and focuses on the control of the highfrequency rectifier for which a number of control strategies are presented. Rather than controlling the rectifier based on a cycle-by-cycle assessment of the system, these strategies consider the capability of the system based on the overall form of the system trajectories. An understanding of these trajectories has allowed the development of control strategies with a high speed of response