CN2706955Y - Boost type active staggered parallel soft switch DC-DC converter - Google Patents

Abstract

The boost type active interleaved parallel soft switch DC-DC converter of the utility model includes two coupled inductors, two freewheeling diodes, two power switch tubes, the drain of the first power switch tube and the second two The anode of the pole tube is connected to one end of the second inductor, the drain of the second power switch tube is connected to the anode of the first diode and one end of the first inductor, and the other end of the first inductor is connected to the other end of the second inductor A series circuit composed of the first capacitor and the first auxiliary switch tube is connected in parallel to the first power switch tube, and a series circuit composed of the second capacitor and the second auxiliary switch tube is connected in parallel to the second power switch tube. The utility model has few additional components, simple structure, no additional detection, no energy loss components in the circuit, can improve the efficiency of the step-up interleaved parallel circuit, and has no voltage overshoot when the power switch tube is turned off during the commutation process.

Description

Step-up Active Interleaved Parallel Soft Switching DC-DC Converter

technical field

The utility model relates to a DC-DC converter. Specifically, it is a step-up active interleaved parallel soft-switching DC-DC converter.

Background technique

A conventional step-up (Boost) interleaved parallel DC-DC converter includes two inductors L1, L2, two freewheeling diodes D1, D2, two power switch tubes S1, S2, and the drain of the first power switch tube S1 The pole is connected with the anode of the second diode D2 and one end of the second inductor L2, the drain of the second power switch tube S2 is connected with the anode of the first diode D1 and one end of the first inductor L1, and the first inductor L1 The other end of is connected to the other end of the second inductor L2. This step-up interleaved parallel DC-DC converter generally works as a hard switch, and the switching loss is relatively large. In recent years, some soft switching circuits have been studied successively. There are two main types: one is to add active and passive components to the converter to realize the soft switching of power devices; the other is to add a passive snubber circuit with resistance , its energy loss is large, and the energy is consumed on the resistance during operation, resulting in a decrease in circuit efficiency.

Contents of the invention

The purpose of the utility model is to provide a step-up active interleaved parallel soft-switching DC-DC converter with few additional components, simple structure, low cost and no energy loss.

The technical solution of the utility model is that the step-up active interleaved parallel soft switch DC-DC converter includes two coupled inductors, two freewheeling diodes, two power switch tubes, and the drain of the first power switch tube The pole is connected to the anode of the second diode and one end of the second inductor, the drain of the second power switch tube is connected to the anode of the first diode and one end of the first inductor, and the other end of the first inductor is connected to the second The other end of the inductance is connected, which is characterized in that a series circuit composed of the first capacitor and the first auxiliary switch tube is connected in parallel with the first power switch tube, wherein the first auxiliary switch tube is in the same direction as the first power switch tube, and the first capacitor It is connected to the junction of the first power switch tube and the second inductor; a series circuit composed of the second capacitor and the second auxiliary switch tube is connected in parallel to the second power switch tube, wherein the second auxiliary switch tube is in the same direction as the second power switch tube , and the second capacitor is connected to the junction of the second power switch tube and the first inductor.

When working, the leakage inductance of the two coupled inductors is used to realize the zero-current turn-on of the first power switch tube and the second power switch tube and the soft turn-off of the first and second freewheeling diodes; the first power switch tube and the second power switch tube When the two power switch tubes are turned off, due to the existence of the first capacitor and the second capacitor, the zero-voltage turn-off of the first power switch tube and the second power switch tube is realized. At the same time, the first and second capacitors collect the energy in each switching cycle, and finally transfer it to the load, realizing the lossless operation of the absorbing circuit. During the whole switching period, by controlling the gate pulses of the first and second auxiliary switching tubes, the first and second auxiliary switching tubes can be turned on and off with zero voltage.

The boost type active interleaved parallel soft-switching DC-DC converter of the utility model utilizes the leakage inductance of the coupling inductor to realize the soft switching of the power switch tube without additional inductive elements, so that there are few additional elements, simple structure and low cost. Low, no additional detection circuit, no energy loss components in the circuit, which can improve the efficiency of the step-up interleaved parallel circuit, and during the commutation process, there is no voltage overshoot when the power switch tube is turned off, and no current when the freewheeling diode is turned on overshoot.

Description of drawings

Figure 1 is a circuit diagram of a step-up active interleaved parallel soft-switching DC-DC converter.

Detailed ways

Referring to Figure 1, the step-up active interleaved parallel soft-switching DC-DC converter includes two phase-coupled inductors L1, L2, two freewheeling diodes D1, D2, two power switch tubes S1, S2, the first power The drain of the switching tube S1 is connected to the anode of the second diode D2 and one end of the second inductor L2, and the drain of the second power switching tube S2 is connected to the anode of the first diode D1 and one end of the first inductor L1 , the other end of the first inductance L1 is connected to the other end of the second inductance L2, which is characterized in that a series circuit composed of the first capacitor C1 and the first auxiliary switch S3 is connected in parallel with the first power switch tube S1, wherein the first auxiliary switch tube S3 The switching tube S3 is in the same direction as the first power switching tube S1, and the first capacitor C1 is connected to the junction of the first power switching tube S1 and the second inductor L2; the second power switching tube S2 is connected in parallel by the second capacitor C2 and the second A series circuit formed by the auxiliary switching tube S4, wherein the second auxiliary switching tube S4 is in the same direction as the second power switching tube S2, and the second capacitor C2 is connected to the junction of the second power switching tube S2 and the first inductor L1.

There are four commutation situations in the step-up active interleaved parallel soft-switching DC-DC converter, that is, the commutation between the first power switch S1 and the first freewheeling diode D1 and the commutation between the first power switch S1 and the second The commutation between the freewheeling diodes D2; the commutation between the second power switch S2 and the second freewheeling diode D2 and the commutation between the second power switch S2 and the first freewheeling diode D1. Due to the symmetry of the circuit structure, only taking the commutation process of the first power switch tube S1 as an example, the analysis is as follows:

The commutation process in which the first power switch S1 is turned on and the first freewheeling diode D1 is turned off:

Before commutation, the circuit is in a stable working state where the first power switch tube S1 is turned off and the first freewheeling diode D1 is freewheeling. When the first power switch S1 is turned on, due to the leakage inductance of the coupled inductors L1 and L2, the current of the first power switch S1 rises linearly from zero with a certain slope, that is, the first power switch S1 realizes zero current turn-on , and at the same time the current value of the first freewheeling diode D1 decreases linearly with the same slope from the input current until the first freewheeling diode D1 is turned off. In this way, the reverse recovery current of the first freewheeling diode D1 is zero, which greatly reduces the reverse recovery loss caused by the first freewheeling diode D1. After the first freewheeling diode D1 is turned off, the second capacitor C2 starts to resonate with the leakage inductance of the coupling inductors L1 and L2 via the body diode of the second auxiliary switching transistor S4 until the voltage on the second capacitor C2 drops to zero. Afterwards, the circuit enters into a stable operation state in which the first power switch tube S1 is turned on.

The commutation process in which the first power switch S1 is turned off and the second freewheeling diode D2 is turned on:

Before the first power switch S1 is turned off, the first auxiliary switch S3 is turned on, because before the first auxiliary switch S3 is turned on, the first power switch S1 has been turned on, so that the first auxiliary switch S3 achieves zero The voltage is turned on. After the first power switch tube S1 is turned off, the input current charges the first capacitor C1 through the first auxiliary switch tube S3, and the tube voltage of the first power switch tube S1 rises from zero, that is, the zero voltage of the first power switch tube S1 is realized. voltage off. When the voltage of the first capacitor C1 is charged to be equal to the voltage of the upper output capacitor terminal, the second freewheeling diode D2 is naturally turned on. After the first power switch S1 is turned off, the first auxiliary switch S3 is turned off. Because the voltage across the first capacitor C1 is the output voltage, the first auxiliary switch S3 realizes zero-voltage turn-off. The circuit enters a steady state where the load current is output through the second freewheeling diode D2.

Claims (1)

1. The step-up active interleaved parallel soft-switching DC-DC converter includes two phase-coupled inductors (L1, L2), two freewheeling diodes (D1, D2), and two power switch tubes (S1, S2) , the drain of the first power switch (S1) is connected to the anode of the second diode (D2) and one end of the second inductor (L2), the drain of the second power switch (S2) is connected to the first diode The anode of the tube (D1) is connected to one end of the first inductance (L1), and the other end of the first inductance (L1) is connected to the other end of the second inductance (L2). It is characterized in that the first power switch tube (S1) A series circuit composed of the first capacitor (C1) and the first auxiliary switch tube (S3) is connected in parallel, wherein the first auxiliary switch tube (S3) is in the same direction as the first power switch tube (S1), and the first capacitor (C1) Connected to the junction of the first power switch tube (S1) and the second inductor (L2); a series circuit composed of the second capacitor (C2) and the second auxiliary switch tube (S4) is connected in parallel to the second power switch tube (S2) , wherein the second auxiliary switching tube (S4) is in the same direction as the second power switching tube (S2), and the second capacitor (C2) is connected to the junction of the second power switching tube (S2) and the first inductor (L1).

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