Active power filter using sliding mode control and p-q theory based reference values

In this paper a shunt three phase active power filter with reference values based on p-q theory, using sliding mode control, is presented. The nonlinear load is composed either of a capacitive and an inductive, or just an inductive component. The filter is analyzed and the mathematical model of the inverter, the state equations of the power system, the sliding mode control with the existence conditions and the stability of the system are determined. For the realization of sliding mode control of the three-phase inverter connected in parallel, when the nonlinear load has a capacitive component, a compensating capacitor is needed, parallel with the active filter. The reference values for the filter are obtained using the instantaneous real and imaginary power theory. The expected results are confirmed by experimentations.