CN203859684U

CN203859684U - Large-current half-bridge circuit

Info

Publication number: CN203859684U
Application number: CN201420253858.4U
Authority: CN
Inventors: 代杰仕; 吕剑
Original assignee: Xi'an Wei Electricity Electrical Technology Co Ltd
Current assignee: Xi'an Wei Electricity Electrical Technology Co Ltd
Priority date: 2014-05-16
Filing date: 2014-05-16
Publication date: 2014-10-01
Anticipated expiration: 2024-05-16

Abstract

The utility model discloses a large-current half-bridge circuit, and the circuit comprises two MOS tubes S1 and S2, which are in parallel connection with a power end. The drainage end of the MOS tube S1 is in parallel connection with a diode D1 and a capacitor Cs1. The drainage end of the MOS tube S2 is in parallel connection with a diode D2 and a capacitor Cs2. The source end of the MOS tube S1 is connected with an inductor Lk and the source end of the MOS tube S2 is connected with a capacitor Cb, and then is connected to the input end of a transformer. The output end of the transformer is in parallel connection with a pair of diode D3 and diode D4 in a reverse manner. The cathode of the diode D3 is connected with an inductor L1, and is connected with the dotted terminal of the secondary side of the transformer. The cathode of the diode D4 is connected with an inductor L2, and is also connected with a non-dotted terminal of the secondary side of the transformer. The inductor L1 and the inductor L2 are mutually connected, and then are connected with a set of capacitor C3 and a load RL which are in parallel connection. The outer end of the set of capacitor C3 and load RL is connected to a node of the diode D3 and the diode D4. The circuit provided by the utility model solves the problems in the prior art that the loss is high, the efficiency is low and the output power is low. The circuit reduces the energy consumption of a converter, and increases the power density.

Description

A kind of large electric current half-bridge circuit

Technical field

The utility model belongs to switch power technology field, relates to the half-bridge circuit of a kind of soft switch and the large electric current of secondary.

Background technology

DC/DC converter is exactly by the direct voltage of input, after high frequency chopping or high-frequency inversion, by rectification and filtering link, converts the direct voltage of required amplitude to.It is all widely used in fields such as household electrical appliance, Industry Control, communication, national defence, traffic.Half-bridge circuit topology, due to advantages such as its cost is low, easy realizations, is occupied critical role in numerous topologys.Conventional half-bridge topology has following two kinds:

1, conventional half bridge topology

Be illustrated in figure 1 conventional half bridge topology topology, the capacitor C1 being equated by capacitance and C2 form one group of bridge, and metal-oxide-semiconductor S1 and S2 form another group bridge, and D1 and D2 are the body diodes of metal-oxide-semiconductor, and Cs1 and Cs2 are the parasitic capacitances of metal-oxide-semiconductor; Two brachium pontis mid point connection transformer T1, after transformer, edge joint rectifier diode D3 and D4 form half-bridge circuit;

Its principle: this circuit drives two metal-oxide-semiconductors by the driving of a pair of complementation, S1 and S2 alternate conduction, at transformer, once survey and produce the positive negative pulse stuffing that an amplitude is Vi/2, and be transferred to secondary side by high frequency transformer, through rectifies, after energy storage inductor L1 and capacitor C3 filtering, power to the load;

Its feature: with respect to full-bridge circuit, this topology has only been used two metal-oxide-semiconductors, and cost is relatively low, owing to being two pipes, does not have the problem of break-make simultaneously, and its anti-unbalance ability is strong, less demanding for duty ratio, so the design of drive circuit is also relatively simple;

Shortcoming: because it is operated in hard switching state, the switching loss on metal-oxide-semiconductor is larger; It is half of input voltage that the transformer primary side of half-bridge circuit bears voltage, so its power output is relatively low, is not suitable for the application of high power load occasion.

2, asymmetry half-bridge circuit

In order to overcome the problems of hard switching circuit, Fig. 2 has proposed a kind of follow-on half-bridge topology, adds leakage inductance Lk in circuit, utilizes the parasitic capacitance of switching tube and the leakage inductance generation resonance of transformer, the no-voltage that realizes circuit is open-minded, to reduce the loss of circuit.

Its principle: main switch is two complementary power MOSFETs (S1 and S2) of controlling, and the time of switching tube S1 and S2 conducting is respectively D and 1-D.Lk is transformer primary side leakage inductance, with parasitic capacitance C1 and the C2 resonance of switching tube, for the no-voltage of power switch tube S 1 and S2, opens and creates conditions.S ₁during conducting, forward voltage is born on the former limit of transformer, secondary winding N ₂₁work, diode D ₃conducting, switching tube S ₂with diode D ₄turn-off S ₂during conducting, reverse voltage is born on the former limit of transformer, auxiliary winding N ₂₂work, diode D ₄conducting, switching tube S ₁with diode D ₃turn-off;

Its feature: soft switch semi-bridge circuit realized to a great extent switch no-voltage open-minded, reduced loss, greatly improve operating frequency and power output, reduce electromagnetic interference.

Shortcoming: power output is lower, seldom applies in high power load occasion.

Utility model content

The purpose of this utility model is to provide a kind of efficiently large electric current half-bridge circuit, has solved the problem that the loss existing in prior art is large, efficiency is low, power output is little.

The purpose of this utility model realizes by following technical proposals.

A kind of large electric current half-bridge circuit, comprise the metal-oxide-semiconductor S1 and the metal-oxide-semiconductor S2 that are connected in power supply E end in parallel, the source termination power E of the drain terminal of described metal-oxide-semiconductor S1 and metal-oxide-semiconductor S2, the drain terminal of described metal-oxide-semiconductor S1 be connected in parallel a diode D1 and capacitor C s1, the drain terminal of metal-oxide-semiconductor S2 be connected in parallel a diode D2 and capacitor C s2; Described metal-oxide-semiconductor S1 source connects after an inductance L k and metal-oxide-semiconductor S2 source meet a capacitor C b and accesses transformer input, transformer output be connected in parallel diode D3 and the diode D4 of a pair of reverse access; Described diode D3 negative electrode connects an inductance L 1, and be connected with transformer secondary Same Name of Ends, described diode D4 negative electrode connects an inductance L 2, and be connected with transformer secondary non-same polarity, described inductance L 1 is connected capacitor C 3 and the load RL of one group of parallel connection again after interconnecting with inductance L 2, capacitor C 3 in parallel and the other end of load RL are connected to the anode node of diode D3 and diode D4.

Further, described diode D1 and diode D2 are parasitic diode.

Further, described capacitor C s1 and capacitor C s2 are parasitic capacitance.

The beneficial effects of the utility model are:

1, reduce transducer loose, increasing power density;

Thereby 2, improve output current and improve power output.

Accompanying drawing explanation

Fig. 1 is conventional half bridge topology figure;

Fig. 2 is soft switch semi-bridge circuit diagram;

Fig. 3 doubly flows rectifying half bridge circuit diagram.

Embodiment

Below in conjunction with drawings and Examples, the utility model is described in further details.

As shown in Figure 3, this large electric current half-bridge circuit, comprise the metal-oxide-semiconductor S1 and the metal-oxide-semiconductor S2 that are connected in power supply E end in parallel, the source termination power E of the drain terminal of described metal-oxide-semiconductor S1 and metal-oxide-semiconductor S2, the drain terminal of metal-oxide-semiconductor S1 be connected in parallel a diode D1 and capacitor C s1, the drain terminal of metal-oxide-semiconductor S2 be connected in parallel a parasitic diode D2 and parasitic capacitance Cs2; Described metal-oxide-semiconductor S1 source connects after an inductance L k and metal-oxide-semiconductor S2 source meet a capacitor C b and accesses transformer input, transformer output be connected in parallel diode D3 and the diode D4 of a pair of reverse access; Described diode D3 negative electrode connects an inductance L 1, and be connected with transformer secondary Same Name of Ends, described diode D4 negative electrode connects an inductance L 2, and be connected with transformer secondary non-same polarity, described inductance L 1 is connected capacitor C 3 and the load RL of one group of parallel connection again after interconnecting with inductance L 2, capacitor C 3 in parallel and the other end of load RL are connected to the anode of diode D3, and are connected with the anode of diode D4.

Wherein, diode D1 and diode D2 are parasitic diode, and capacitor C s1 and capacitor C s2 are parasitic capacitance.

This main circuit switch is two complementary power MOSFETs (S1 and S2) of controlling, the duty ratio of S1 and S2 is respectively D and 1-D, D1, D2 are respectively the body diode of S1 and S2, resonant capacitance CS1 and CS2 are the parasitic capacitances of S1 and S2, the voltage source of capacitance Cb during as switching tube S2 conducting, depressor T is equivalent to a leakage inductance Lk of ideal transformer series connection, the transformer primary side number of turn is N1, the secondary number of turn is N2, adopt and doubly flow rectification, with Ultrafast recovery diode D3 and D4, output inductor L1 and L2, filter capacitor C3 and load RL.

Operation principle of the present utility model:

1, after switching tube S1 turn-offs, leakage inductance Lk and Cs1 and Cs2 resonance, transformer leakage inductance electric current flows through Cs1 and Cs2, make the voltage linear of capacitor C s1 increase, the voltage linear of capacitor C s2 declines, and when capacitor C s2 voltage drop arrives zero, the body diode D2 conducting of S2 arrives zero by the voltage clamping on S2, now opening S2, just to realize no-voltage open-minded, after S2 opens, under bearing on transformer secondary, just, secondary current forms loop by L2, C3 and RL, D3, L2 energy storage, inductance L 1 releases energy by D3;

2, switching tube S ₂after shutoff, circuit restarts to enter the capacitor charge and discharge stage, and transformer primary side electric current flows through Cs1 and Cs2, the voltage linear of capacitor C s1 is declined, the voltage linear of capacitor C s2 rises, and when Cs1 voltage drop arrives zero, the body diode D1 conducting of S1 arrives zero by the voltage clamping on S1, now opening S1, just to realize no-voltage open-minded, after S1 opens, just lower negative on transformer secondary, secondary current forms loop by L1, C3 and RL, D4, L1 energy storage, L2 releases energy by D4.

Feature of the present utility model is:

1, switching tube is realized soft switch by the resonance of leakage inductance and parasitic capacitance, thereby has reduced switching loss, raises the efficiency;

2, secondary adopts and doubly to flow commutation technique, due to arbitrary filter inductance electric current be output load current half, thereby increased output current, improve power output;

3, doubly flowing rectification is by the crisscross parallel of two inductance, and the voltage on two output inductors and the current and phase difference flowing through are 180 °.Realized the mutual partial offset of the ripple current on filter inductance, therefore the ripple of load current is less.

The foregoing is only a kind of execution mode of the present utility model, it not whole or unique execution mode, the conversion of any equivalence that those of ordinary skills take technical solutions of the utility model by reading the utility model specification, is claim of the present utility model and contains.

Claims

1. a large electric current half-bridge circuit, comprise the metal-oxide-semiconductor S1 and the metal-oxide-semiconductor S2 that are connected in power supply E end in parallel, the source termination power E of the drain terminal of described metal-oxide-semiconductor S1 and metal-oxide-semiconductor S2, it is characterized in that: the drain terminal of described metal-oxide-semiconductor S1 be connected in parallel a diode D1 and capacitor C s1, the drain terminal of metal-oxide-semiconductor S2 be connected in parallel a diode D2 and capacitor C s2; Described metal-oxide-semiconductor S1 source connects after an inductance L k and metal-oxide-semiconductor S2 source meet a capacitor C b and accesses transformer input, transformer output be connected in parallel diode D3 and the diode D4 of a pair of reverse access; Diode D3 negative electrode connects an inductance L 1, and be connected with transformer secondary Same Name of Ends, diode D4 negative electrode connects an inductance L 2, and be connected with transformer secondary non-same polarity, inductance L 1 is connected capacitor C 3 and the load RL of one group of parallel connection again after interconnecting with inductance L 2, capacitor C 3 in parallel and the other end of load RL are connected to the anode node of diode D3 and diode D4.

2. a kind of large electric current half-bridge circuit according to claim 1, is characterized in that: described diode D1 and diode D2 are parasitic diode.

3. a kind of large electric current half-bridge circuit according to claim 1, is characterized in that: described capacitor C s1 and capacitor C s2 are parasitic capacitance.