UPS circuit configuration incorporating buck-boost chopper circuit with two magnetically coupled coils

In recent years, UPS circuit configuration without a transformer has attracted special interest. In such UPS topology, the boost chopper circuit is very important for stepping up the battery voltage. Problems with conventional boost chopper circuits are that a high step-up ratio worsens efficiency, and that there is a voltage imbalance between the high side and the low side of DC link voltage. The circuit configuration proposed overcomes the shortcomings of the conventional circuit configuration by employing a buck-boost chopper circuit with two magnetically coupled coils.