Abstract
M.Ing. (Electrical & Electronic Engineering)
Three single phase current fed converters operating in pwm mode, are combined as an
active power filter of 15 kVA.
The undesired limit cycle shown by the system is eliminated by feedback loop
compensation. Analog, computer and analytical models which predict remarkably similar
system responses are used to investigate the technique. The analytical model involves
describing function methods.
The losses in the converters are modelled, and used as a feedback reference to allow
losses in the system to be accurately covered from the supply.
The system behaves as an accurate, fast active filter for distortion in power networks.
Results illustrating this include the time and frequency response of the system for
different reference currents. This is shown for the computer simulation as well as the
practical system. Some more results include the response of the system to both a
balanced and an unbalanced set of references in the three phases. The last results
shown, illustrate the ability of the system to compensate a non-linear load.