DZW75-48/50(50II) high frequency conversion circuit

The high-frequency converter adopts a full-bridge structure. The IGBTs on the four arms are driven by four mutually isolated drivers. Their working power supply is 300V. Under the action of the driving pulse, the high-frequency switching tubes on the two diagonals take turns. It is turned on or off at the same time, so that high-frequency pulse voltage is obtained at the primary and secondary sides of the main transformer to achieve high-frequency conversion of DC/AC. When the driving pulses 1# and 4# are at positive potential at the same time, IGBT1 and IGBT4 are turned on at the same time. At this time, the driving pulses of IGBT2 and IGBT3 are both at negative potential and are reliably cut off. Current will flow through the primary of main transformer T, and the current The direction is from terminal 1 to terminal 2, and the primary induced voltage is set to a positive pulse with an amplitude of about 300V. When the driving pulses 2# and 3# are at positive potential at the same time, IGBT2 and IGBT3 are turned on at the same time. At this time, the driving pulses of IGBT1 and IGBT4 are at negative potential at the same time and are reliably cut off. The primary side of the main transformer T will have reverse current flowing through it. , that is, flowing from terminal 2 to terminal 1, the primary induced voltage is a negative pulse with an amplitude of about 300V. In this way, as the driving pulse changes, a positive and negative alternating pulse voltage is generated on the primary side of the main transformer T (correspondingly also on the secondary side of T), and a positive and negative alternating high-frequency pulse current flows, as shown in the figure below. Show.