New topology for harmonic-free, dynamic VAr compensator using unidirectional power switches

This paper presents a new and simple topology for reactive power compensators. It is based on a branch of binary scaled capacitors, and a special and simple switching device, implemented with one thyristor, and one antiparallel diode. During the off state, the capacitors remain charged at the peak voltage. When connected, they are switched on when the line voltage reaches its peak value. The main characteristics of this new topology are: (1) it does not generate harmonics; (2) it is simpler and less expensive compared with other topologies using electronic VAr compensators; (3) it can compensate reactive power cycle by cycle; (4) it does not require force commutated switches; and (5) inrush problems during connection and/or disconnection are avoided, allowing a dynamic compensation of reactive power. The paper analyzes the circuit proposed, the way it works and the results obtained under operation