Abstract: The present invention provides a transformer, which is applied to the technical field of power transmission and distribution, the transformer comprising an iron core, body windings, and a semi-conductive layer, the body windings being sleeved on a core post of the iron core, and the semi-conductive layer being correspondingly provided with the body windings. Auxiliary circuits are connected to the body windings, the auxiliary circuits and preset positions of the body windings have equal potentials, and an equipotential connection point of the semi-conductive layer is provided by the auxiliary circuits. After the semi-conductive layer is connected to the auxiliary circuits, the effect of balancing the electric field distribution of a winding can be achieved.

Abstract: Provided is a bridge cascade system, which includes at least one phase unit and a driving unit for the phase unit. The phase unit includes N bridge topologies cascaded on alternating current AC sides. The driving unit includes one driving power supply circuit, multiple bootstrap power supply circuits and 2N driving circuits. In the phase unit, the driving circuits are powered by the driving power supply circuit directly or through corresponding bootstrap power supply circuits. The driving circuits are configured to provide driving signals for corresponding switch transistors in the phase unit. In this way, one driving power supply is matched with multiple bootstrap power supply circuits, realizing power supply to the driving circuits corresponding to the switch transistors of all bridge topologies, which reduces the difficulty in designing the driving power supply for the bridge cascade system and reduces cost for the system.

Abstract: Provided is a bridge cascade system, which includes at least one phase unit and a driving unit for the phase unit. The phase unit includes N bridge topologies cascaded on alternating current AC sides. The driving unit includes one driving power supply circuit, multiple bootstrap power supply circuits and 2N driving circuits. In the phase unit, the driving circuits are powered by the driving power supply circuit directly or through corresponding bootstrap power supply circuits. The driving circuits are configured to provide driving signals for corresponding switch transistors in the phase unit. In this way, one driving power supply is matched with multiple bootstrap power supply circuits, realizing power supply to the driving circuits corresponding to the switch transistors of all bridge topologies, which reduces the difficulty in designing the driving power supply for the bridge cascade system and reduces cost for the system.

Abstract: An electric vehicle drive system, a backup power supply device and a backup power supply method for an electric vehicle drive system are provided. The method includes: converting a voltage on a high voltage DC bus of an electric vehicle into a backup input voltage; determining whether a low voltage battery in the electric vehicle drive system has power supply abnormity; and determining the backup input voltage to be an input voltage of a low voltage power supply circuit in the electric vehicle drive system, in a case that the low voltage battery has power supply abnormity.

Abstract: An electric vehicle drive system, a backup power supply device and a backup power supply method for an electric vehicle drive system are provided. The method includes: converting a voltage on a high voltage DC bus of an electric vehicle into a backup input voltage; determining whether a low voltage battery in the electric vehicle drive system has power supply abnormity; and determining the backup input voltage to be an input voltage of a low voltage power supply circuit in the electric vehicle drive system, in a case that the low voltage battery has power supply abnormity.