Use of multilevel inverter for elimination of harmonics in high voltage systems

In this paper five level multilevel inverter based shunt active power filter is presented. Active power filters (APF) are effective to reduce harmonics due to non-linear loads in low voltage system. But its use in high and medium voltage system is limited due to semiconductor rating constraints. In high voltage system high rating transformer is required with APF which causes high cost and bulky system. But application of multilevel inverter in active filters effectively reduces harmonics in high voltage system without use of transformer. The signal reference is generated by using p-q theory considering loss component of APF by comparing dc capacitor voltages with reference dc voltage. Carrier phase shifted pulse width modulation scheme is implemented to generate switching signals. Simulated results prove the effective elimination of harmonics with multilevel inverter in high power system.