We report remarkable multiferroic effects in polycrystalline Bi 2 Fe 4 O 9 . High-resolution X-ray diffraction shows that this compound has orthorhombic structure. Magnetic measurements confirm an antiferromagnetic transition around 260 K. A pronounced inverse S-shape anomaly in the loss tangent of dielectric measurement is observed near the Néel temperature. This feature shifts with the application of magnetic field. These anomalies are indicative of substantial coupling between the electric and magnetic orders in this compound.

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Distribution system possesses high resistance to reactance ratio and unbalanced load profile. Introduction of power electronic devices such as solar photovoltaic (PV) inverter in the distribution system leads to power imbalance and unregulated voltage profile at the point of common coupling (PCC) because these devices having low-voltage ride through feature remain connected to grid during fault and inject balanced current to unbalanced fault. Also, high PV integration may increase the voltage at PCC beyond its desired limit. To overcome such unbalanced conditions and to maintain voltage at PCC, a positive, negative and zero sequence-based current controller with reactive power compensation is proposed in this work. The sequence controller controls the sequence currents to their reference command. DC-link voltage regulator, reactive power compensator and PCC voltage regulator decide the references for sequence currents. The proposed reactive power compensator uses both positive sequence voltage at PCC and reactive power supplied by the filter capacitor to generate the reactive power reference value. Feedforward and feedback actions are involved in the controller to produce switching pulses for inverter. The proposed method is tested in OPAL-RT for real-time validation using IEEE 13 bus distribution system model and found to be accurate.

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