Real time optimisation of active filter energy savings

Due to advances in power electronics, many loads now draw a nonsinusoidal or distorted current from the supply. For the same real power, the kVA level for the harmonic load is greater than the equivalent sinusoidal load. Therefore the industrial user of harmonic loads has a greater energy cost. To reduce the distortion drawn from the power system, a shunt active filtering system has been developed. A relationship for determining the savings made from active filtering is derived and this savings function has been implemented in an intelligent controller using a TMS320C30 Digital Signal Processor. The simplex method is used to determine the optimum operating point, taking into account supply current distortion and the cost of energy. The active filter is thus able to determine its own operating point (DC bus voltage and average switching frequency) which maximises savings within a given set of constraints