DC power supply to the inverter is obtained from an existing power grid or from a rotary alternator through a rectifier or a battery, a fuel cell, a photovoltaic system or a magneto-hydrodynamic generator. The filter capacitor on the inverter input terminals provides a constant DC link voltage. The inverter is therefore a voltage source with adjustable frequency. The configuration of AC-DC converter and DC-AC inverter is called DC-link converter. Inverters can be broadly classified into two types, voltage source and current source