DC-DC converter with snubber circuit

Abstract

In order to achieve an object to reduce a surge voltage and suppress noise generation, the present invention provides a DC-DC converter with a snubber circuit, which boosts a voltage Vi of a DC power supply. The snubber circuit includes: a series circuit connected to both ends of a smoothing capacitor Co and including a snubber capacitor Cs and a snubber resistor Rs; a snubber diode Ds1 connected to a node at which the snubber capacitor Cs and the snubber resistor Rs are connected, and to a node at which a reactor Lr1 and an additional winding 1b of a transformer T1 are connected; and a snubber diode Ds2 connected to the node at which the snubber capacitor Cs and the snubber resistor Rs are connected, and to a node at which a reactor Lr2 and an additional winding 2b of a transformer T2 are connected.

Description

technical field [0001] The invention relates to a DC-DC converter with a snubber circuit composed of a step-up chopper circuit, in particular to a DC-DC converter with a snubber circuit suitable for electric vehicles. Background technique [0002] figure 1 It is a circuit configuration diagram of a conventional DC-DC converter described in Japanese Patent Application Laid-Open No. 2006-262601. The step-up DC-DC converter includes a DC power supply Vdc1 , a transformer T3 , a transformer T4 , a reactor L3 , a switch Q1 , a switch Q2 , a diode D3 , a diode D4 , a smoothing capacitor C1 , and a control circuit 100 . [0003] The transformer T3 has: a primary coil 5a (number of turns np), a booster coil 5b (number of turns np1) connected in series with the primary coil 5a, and a secondary coil 5c (number of turns ns) electromagnetically coupled to the primary coil 5a and the booster coil 5b. ). The transformer T4 has the same structure as the transformer T3, and has a primary...

AI Technical Summary

Problems solved by technology

[0017] However, even if the recovery loss of the diodes D3 and D4 can be suppressed, resonance occurs between the reactors La and Lb added to suppress the recovery loss and the capacitance of the depletion layers of the diodes D3 and D4 that are turned off and in the reverse blocking state. , because of this resonance will generate surge voltage and ringing

Therefore, noise that destroys components such as switches will be generated

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