NOVELTY - The product has a main body comprising a double frequency ripple compensator, a low value capacitor to store energy, and a low value inductor to store energy. The ripple compensator comprises a cascade combination of a boost converter and a zeta converter. The ripple compensator is connected in series with the converter to reduce double frequency ripple. The low value capacitor is used as a film capacitor. The zeta converter is operated in a discontinuous conduction mode (DCM) to reduce switching losses. Boost converter switches (S1) are operated synchronously to reduce conduction losses.    USE - Product i.e. low frequency ripple reduction compensator, for reducing double grid frequency ripple for a battery charger application of an electric vehicle. Can also be used for grid connected interfaces for renewable energy e.g. solar PV, powering applications of an LED lighting system and power factor correction (PFC) applications.    ADVANTAGE - The product reduces double frequency ripple in a single phase system in an effective manner, provides a simple control unit, and reduces compensator size and weight. The ripple compensator is provided as a combination of the zeta and boost converters connected in series with the battery charger, so as to reduce an electrolytic capacitor value, thus enhancing life of the charger. The product has high efficiency, modular structure and low capacitor value, and provides compact and light double grid frequency ripple reducing technique for battery charger applications. The product avoids an active source for compensating double frequency power, and reduces weight of the system by avoiding need to utilize a low frequency transformer. The product provides the switch in the converter with low voltage stress, so that a MOSFET can be used for high frequency operation and can be switched synchronously to reduce conduction losses by replacing a diode by the MOSFET and switching the diode synchronously. The zeta converter is operated in a discontinuous conduction mode, so that the diodes are switched in a zero current condition, thus reducing switch losses. The product reduces current ripple and capacitor by 25 times approximately amount without reduction in frequency, reduces voltage ripple across the compensating capacitor, improves overall system efficiency, reduces cost of the compensating converters due to low value of components, and makes a control algorithm to be simple to implement.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for reducing grid frequency ripple for a battery charger application.    DESCRIPTION OF DRAWING(S) - The drawing shows a circuit diagram of a ripple reduction circuit.    Capacitors (C1-C3)    Diodes (D1, D2)    Inductors (L1, L2)    Boost converter switches (S1)