Circulating-current reducing circuit and transformer unit

A transformer unit comprising:

• a first transformer device having a first primary coil on a primary side thereof, the first primary coil having a first impedance;
• a second transformer device that is connected to the first transformer device in parallel, the second transformer device having a second primary coil on a primary side thereof, the second primary coil having a second impedance;
• a controlling element configured to control supply timing of current to the first primary coil and the second primary coil;
• a first circuit that is connected between the controlling element and the first primary coil, the first circuit being connected to the first primary coil in series, the first circuit having a first rectifier element and a first resistance element;
• and
• a second circuit that is connected between the controlling element and the second primary coil, the second circuit being connected to the second primary coil in series, the second circuit having a second rectifier element and a second resistance element,
• wherein the first rectifier element and the first resistance element are connected in parallel to the second rectifier element and the second resistance element,
• wherein a resistance value of the first rectifier element and the first resistance element is lower than each of the first impedance and the second impedance, and
• a resistance value of the second rectifier element and the second resistance element is lower than each of the first impedance and the second impedance.

A circulating-current reducing circuit that is connected to a transformer unit to reduce circulating current occurring in the transformer unit,

• the transformer unit including:
• a first transformer device;
• a second transformer device that is connected to the first transformer device in parallel;
• and
• a controlling element that controls timing of supply of current to a first primary coil portion on a primary side of the first transformer device and a second primary coil portion on a primary side of the second transformer device,
• the circulating-current reducing circuit including:
• a first circuit that is connected in series only between one end of the first primary coil and a node of the controlling element, the first circuit having a first rectifier element and a first resistance element;
• and
• a second circuit that is connected in series only between one end of the second primary coil and the node of the controlling element, the second circuit having a second rectifier element and a second resistance element,
• wherein the first circuit is a first closed loop circuit by connecting the first rectifier element and the first resistance element in series, and the second circuit is a second closed loop circuit by connecting the second rectifier element and the second resistance element in series, and
• when the circulating current is generated between the first primary coil and the second primary coil, the first and second rectifier elements are configured to restrict a current flow direction of the circulating current and the first and second resistance elements are configured to consume the circulating current so that the first and second circuits are configured to reduce the circulating current flowing outside the first and second circuits.