Original edge clamp circuit of DC converter

Abstract

The utility model provides a primary side clamping circuit of a direct current converter. An anti-leakage capacitance is arranged between connections of the clamped point which is in the middle of a resonant inductance and a transformer, and the clamping diode, so as to cut off the release or bypass channel from a blocking capacitance through the clamping diode. Therefore, the transformer can be effectively prevented from working in magnetic biasing state under the conditions that the clamping performance is basically constant when the voltages of the positive and negative bus-bars are balanced, the voltages of the positive and negative input bus-bars are different, or driving pulses widths of positive and negative half-cycle from the switching tube are inconsistent, so that the reliability of the whole circuit is promoted, the current stress of the clamping diode is reduced. The clamping performances of two terminal voltages of the transformer and the both terminal voltages of the transformer secondary side rectifier diode are improved.

Description

technical field [0001] The invention relates to a primary side clamping circuit of a DC converter. Background technique [0002] The topology of the three-level DC / DC clamping circuit that has been published is shown in Fig. 1 and Fig. 2 . VC+ and VC- are positive and negative DC voltage sources respectively, Q1~Q4 are switching tubes, D1~D4 are anti-parallel diodes, D7~D8 are clamping diodes, D9~D10 are freewheeling diodes, D5~D6 are output rectifier diodes , Cb is a DC blocking capacitor, Lr is a resonant inductor, T1 is a transformer, Lf is an output inductor, Cf is an output capacitor, and R1 is a load. In Figure 1, D7 and D8 are connected between Lr and T1 to form a clamping circuit, and the voltage at both ends of the transformer T1 is clamped at VC+ and VC-; in Figure 2, the clamping circuit is composed of D1, D7, D8, D4 and Composed of Lr and T1. [0003] Since the three-level DC / DC input is composed of positive and negative DC voltage sources VC+ and VC-, in prac...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a primary side clamping circuit of a DC converter, to solve the problem that the clamping circuit topology in the prior art described above will provide a discharge channel for the DC blocking capacitor Cb under certain working conditions, causing the transformer T1 bias magnetic saturation, and then lead to the problem of damage to the switch tube

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