CN213185889U - BUCK converter and equipment - Google Patents

Abstract

The utility model discloses a BUCK converter and equipment. The utility model discloses an introduce coupling inductance component, including primary winding, secondary winding, excitation inductance and leakage inductance etc. through the branch road of the formation of secondary winding and third diode, the excitation inductance sets up with first switch tube, primary winding, leakage inductance, the relation of connection of second switch tube and other components for excitation inductance current stress is low and the voltage stress of third diode is little, and this stress between them can be along with duty cycle reduction and increase, consequently the utility model discloses a BUCK converter can be applicable to at big duty cycle, the little occasion of required excitation inductance, can effectively reduce the loss, but wide application in power conversion technical field.

Description

BUCK converter and equipment

Technical Field

The utility model belongs to the technical field of the power conversion technique and specifically relates to a BUCK converter and equipment.

Background

In a BUCK converter, the application of zero voltage soft switching technology can effectively reduce switching losses and improve converter efficiency. For example, by active clamp zero voltage soft switching techniques, quasi-resonant zero voltage soft switching techniques, zero voltage transfer soft switching, and the like. The existing synchronous rectification buck converter is provided with an inductor, a capacitor, a switching device, a load connected in parallel with the capacitor and the like, the inductor, a resonant capacitor used in a resonant process and the like, and the stress of the inductor current and the voltage stress of the switching device are high and the loss is large under the condition of large duty ratio.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical problem, the utility model aims to provide a: a BUCK converter and an apparatus are provided.

The utility model adopts the technical proposal that: a BUCK converter, comprising: the circuit comprises a coupling inductance element, a first capacitor, a second capacitor, a third capacitor, a first diode, a second diode, a third diode, a first switch tube, a second switch tube and a power supply, wherein the coupling inductance element comprises a primary coil, a secondary coil, an excitation inductance and a leakage inductance;

a collector of the second switch tube is connected with an emitter of the first switch tube, one end of the leakage inductor, a cathode of the first diode and one end of the first capacitor, and an emitter of the second switch tube is connected with an anode of the first diode, the other end of the first capacitor and an anode of the third diode;

the non-dotted terminal of the secondary coil is connected with the anode of the power supply and the collector of the first switching tube, the dotted terminal of the secondary coil is connected with the cathode of the third diode, and the anode of the third diode is connected with the cathode of the power supply;

the other end of the leakage inductor is connected with one end of the excitation inductor and the homonymous end of the primary coil, the other end of the excitation inductor is connected with the non-homonymous end of the primary coil and one end of a third capacitor, the other end of the third capacitor is connected with the negative electrode of the power supply, and the third capacitor is used for being connected with a load in parallel;

the collector of the first switch tube is connected with the cathode of the second diode, the emitter of the first switch tube is connected with the anode of the second diode, and the second capacitor is connected with the second diode in parallel.

The utility model also provides an equipment, include the BUCK converter with the load.

The utility model has the advantages that: by introducing the coupling inductance element, the coupling inductance element comprises a primary coil, a secondary coil, an excitation inductance, a leakage inductance and the like, the connection relation between the excitation inductance and the first switching tube, the primary coil, the leakage inductance and the second switching tube is set through a branch formed by the secondary coil and the third diode, so that the current stress of the excitation inductance is low, the voltage stress of the third diode is small, and the stresses of the excitation inductance and the primary coil and the leakage inductance are increased along with the reduction of the duty ratio.

Drawings

Fig. 1 is a schematic diagram of a BUCK converter according to the present invention;

FIG. 2 is a schematic diagram of the variation of parameters in the operation process of the BUCK converter of the present invention.

Detailed Description

In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The terms "first," "second," "third," and the like in the description and claims of this application and in the drawings are used solely to distinguish one from another and are not used to describe a particular sequence. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

The invention will be further explained and explained with reference to the drawings and the embodiments in the following description.

Referring to fig. 1, an embodiment of the present invention provides a BUCK converter suitable for a small excitation inductive current and a large duty ratio, including a coupling inductive element, a first capacitor C1, a second capacitor C2, a third capacitor C3, a first diode D1, a second diode D2, a third diode D3, a first switch tube S₁A second switch tube S₂And a power supply V_inWherein the coupling inductance element comprises a primary coil N1, a secondary coil N2 and an excitation inductance L_mAnd leakage inductance L_r；

The second switch tube S₂Collector electrode of the first switch tube S₁Emitter of, said leakage inductance L_rOne terminal, the cathode of the first diode D1, one terminal of the first capacitor C1, and the second switch tube S₂Is connected with the anode of the first diode D1, the other end of the first capacitor C1 and the anode of the third diode D3;

the non-homonymous end of the secondary coil N2 is connected with the power supply V_inAnd the first switching tube S₁The dotted terminal of the secondary winding N2 is connected to the cathode of the third diode D3, and the anode of the third diode D3 is connected to the power source V_inThe negative electrode of (1);

the leakage inductance L_rThe other end is connected with the excitation inductor L_mOne end and the dotted end of the primary coil N1, the excitation inductance L_mThe other end of the primary coil N1 is connected with a non-dotted terminal of the primary coil N1 and one end of the third capacitor C3, and the other end of the third capacitor C3 is connected with the power supply V_inThe third capacitor C3 is used for being connected in parallel with the load R;

the first switch tube S₁Is connected to the cathode of the second diode D2, the first switching tube S₁Is connected to the anode of the second diode D2, and the second capacitor C2 is connected in parallel with the second diode D2.

Referring to FIG. 2, the pulse signal includes, but is not limited to, the pulse signal S shown in the figure₁、S₂And the adjustment can be carried out according to actual requirements.

The following detailed description describes the specific working process of the present invention:

1、(t₁～t₂) At t₁Before the moment, the first switch tube S₁On, the third diode D3 is turned on and its current i_D1Decrease (current of leakage inductance Lr)

Increase at t₁Time, leakage inductance voltage V_LrDecrease i_D1Decreasing to zero, the third diode D3 is then turned off. Leakage inductance L_rAnd an excitation inductance L_mBy charging, the excitation current remains unchanged.

2、(t₂～t₃) At t₂At any moment, the first switch tube S is turned off₁When the second capacitor starts to charge, the second switch tube S₂Parallel C1 begins to discharge, S₂Voltage between collector and emitter (collector and emitter)

Begins to fall while the voltage v across the third diode D3_D1And decreases.

3、(t₃～t₄) At t₃At the moment, the voltage v across the third diode D3_D1Reduced to zero and conducted, exciting inductance L_mVoltage across

Fixed due to clamping effect

(where N is the turn ratio of the secondary coil to the primary coil of the coupling inductance element) in parallel with S₁、S₂Capacitance at both ends and L_rResonance, first capacitor voltage

And continues to decrease.

4、(t₄～t₅) At t₄When the temperature of the water is higher than the set temperature,

reduced to zero, the collector-emitter (collector-emitter) current is conducted through the first diode D1, ensuring S₂Zero voltage turn on, flowing through S₂Current of

Increase, eliminate S₂Reverse recovery of (3). Flow through leakage inductance L_rCurrent of

Decrease to t₅Time of day

Reduced to minimum current

To eliminate S₂Can further ensure

NV_out-V_in>0; the third diode D3 is turned on and the current i_D1And is increased.

5、(t₅～t₆) At t₅Time of day, S₂Turn-off, collector (collector and emitter) voltage

Increase from zeroZero voltage turn-off is achieved (by the first capacitor C1),

to give S₂Charging the parallel C1 to generate a resonance process, and connecting the parallel C1 to the first S₁、S₂Capacitance and leakage inductance L at both ends_rAnd (4) resonating.

6、(t₆～t₇) At t₆At the moment of time, the time of day,

rises to v_in，S₁Current of

Flows through the anti-parallel diode (second diode D2) and the leakage inductance L_rIncrease in current, V_in+N(V_in-V_out)>0，

Is increased and at t₆The time instant increases to zero. At this stage S₁The switch-on can be realized by zero voltage; the current flowing through the third diode D3 decreases.

7、(t₇～t₈) At t₇Time of day, S₁Current of

Starting from negative to positive, to t₈At that point, the current in the third diode D3 decreases to zero and the entire switching cycle ends.

The present embodiment also provides an apparatus including the BUCK converter and the load.

While the preferred embodiments of the present invention have been described, the present invention is not limited to the above embodiments, and those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and such equivalent modifications or substitutions are intended to be included within the scope of the present invention as defined by the appended claims.

Claims (2)

1. A BUCK converter, comprising: the circuit comprises a coupling inductance element, a first capacitor, a second capacitor, a third capacitor, a first diode, a second diode, a third diode, a first switch tube, a second switch tube and a power supply, wherein the coupling inductance element comprises a primary coil, a secondary coil, an excitation inductance and a leakage inductance;

a collector of the second switch tube is connected with an emitter of the first switch tube, one end of the leakage inductor, a cathode of the first diode and one end of the first capacitor, and an emitter of the second switch tube is connected with an anode of the first diode, the other end of the first capacitor and an anode of the third diode;

the non-dotted terminal of the secondary coil is connected with the anode of the power supply and the collector of the first switching tube, the dotted terminal of the secondary coil is connected with the cathode of the third diode, and the anode of the third diode is connected with the cathode of the power supply;

the other end of the leakage inductor is connected with one end of the excitation inductor and the homonymous end of the primary coil, the other end of the excitation inductor is connected with the non-homonymous end of the primary coil and one end of a third capacitor, the other end of the third capacitor is connected with the negative electrode of the power supply, and the third capacitor is used for being connected with a load in parallel;

the collector of the first switch tube is connected with the cathode of the second diode, the emitter of the first switch tube is connected with the anode of the second diode, and the second capacitor is connected with the second diode in parallel.

2. An apparatus, characterized by: comprising the BUCK converter according to claim 1 and the load.

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