Improved topological structure based on BOOST and LLC power topology

Abstract

The utility model discloses an improved topological structure based on BOOST and LLC power topology, which comprises a switching circuit, a full-bridge LLC bridge arm and a main switching tube which are connected in parallel with the input end of the switching circuit, and a first inductor connected with the full-bridge LLC bridge arm, and the output end of the switching circuit is connected with a transformer through a first filter capacitor and a second inductor. The secondary side of the transformer is connected in parallel with a switching tube assembly and a third filter capacitor; according to the utility model, the efficiency upper limit of the two-stage power topology architecture can be improved, the output power of the BOOST circuit is reduced by half, the use of power devices can be reduced, the cost is saved, the weight and the size of an inductor can be effectively reduced, the weight and the size of a DC / DC converter can be obviously reduced, the gain of a full-bridge LLC resonant cavity is ensured, and the output power of the two-stage power topology architecture is improved. And the stability of the output voltage of the DC / DC converter under the working condition of low input voltage is ensured.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of DC / DC converter, concretely is an improved topology structure based on BOOST and LLC power topology. BACKGROUND

[0002] With the development of power electronics technology, in order to adapt to wide range voltage input, there are isolation requirements scene, at present, most in the industry adopts two-stage power topology architecture;In recent years, with the iteration of technology, the mainstream direction of secondary power is developed to high power density and high efficiency.

[0003] At present, in the secondary power industry, the traditional two-stage topology architecture used by high-power DC / DC converter is limited by power device parameters, circuit design, etc., and its theoretical design upper limit efficiency is basically around 96.5%, with the development of market competition, many power manufacturers have given different technical schemes, aiming at developing high-power and high-efficiency modules, two-stage power topology has natural disadvantages compared with single-stage topology efficiency index, but it has greater advantages in adapting to input voltage scene. SUMMARY

[0004] The utility model discloses a kind of improved topology structure based on BOOST and LLC power topology, to solve the problem raised in the above background technology.

[0005] To achieve the above object, the utility model provides the following technical scheme: an improved topology structure based on BOOST and LLC power topology, including switching circuit, full-bridge LLC bridge arm and main switch tube parallelly connected with the input end of switching circuit, and the inductor of one, the output end of switching circuit is connected with transformer by first filter capacitor, secondary inductor, the secondary side of the transformer is parallelly connected with switch tube assembly and third filter capacitor, main switch tube, the input end of inductor of one and full-bridge LLC bridge arm connects output input voltage.

[0006] Further, the switching circuit is composed of switch tube Q3, switch tube Q4, switch tube Q5 and switch tube Q6, the switch tube Q5 is connected together with switch tube Q6, switch tube Q3 is connected together with switch tube Q4, and capacitor C2 is connected in parallel between the free end of switch tube Q3 and switch tube Q4.

[0007] Further, the full-bridge LLC bridge arm includes first switch tube, second switch tube and diode D1, the first switch tube is connected together with second switch tube, and the common connection end of first switch tube and second switch tube is connected with inductor of one, and diode D1 is connected in parallel across second switch tube.

[0008] Further, the switch tube assembly is composed of a third switch tube and a fourth switch tube, input ends of the third switch tube and the fourth switch tube being connected at a secondary side of the transformer.

[0009] The utility model discloses beneficial effect is: improve the efficiency upper limit of two -stage power topology framework, and the output power of BOOST circuit has reduced half, and power device use can also reduce and save the cost with it, can effectively reduce inductance weight and volume, then to DC / DC converter weight and volume all have obvious reduction, guarantee full -bridge LLC resonant cavity's gain simultaneously, ensure the stability of DC / DC converter output voltage under the working condition of low input voltage. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 It is the principle block diagram of the utility model.

[0011] In the drawing: 1 - first inductance, 2 main switch tube, 3 second switch tube, 4 first switch tube, 5 switching circuit, 6 first filter capacitor, 7 second inductance, 8 transformer, 9 third switch tube, 10 fourth switch tube, 11 third filter capacitor. DETAILED DESCRIPTION

[0012] The technical scheme in the embodiments of the utility model will be described clearly and completely below in combination with the drawings in the embodiments of the utility model, and obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by the person skilled in the art without creative labor belong to the range of protection of the utility model.

[0013] Please refer to Figure 1The utility model provides a technical scheme, an improved topology based on BOOST and LLC power topology, including switching circuit 5, with switching circuit 5 input parallel full -bridge LLC bridge arm and main switch tube 2, and with full -bridge LLC bridge arm connection primary inductance 1, the output of switching circuit 5 is connected with transformer 8 through first filter capacitance 6, secondary inductance 7, the secondary side of this transformer 8 is parallel with switch tube assembly and third filter capacitance 11, and the input of main switch tube 2, primary inductance 1 and full -bridge LLC bridge arm is connected output input voltage, switching circuit 5 is composed of switch tube Q3, switch tube Q4, switch tube Q5 and switch tube Q6, and switch tube Q5 is connected together with switch tube Q6, switch tube Q3 is connected together with switch tube Q4, and parallel capacitor C2 between the free end of switch tube Q3 and switch tube Q4, switch tube assembly is composed of third switch tube 9 and fourth switch tube 10, and the input of third switch tube 9 and fourth switch tube 10 is connected in transformer 8 secondary side position, and third switch tube 9 can be marked as switch tube Q7, fourth switch tube 10 can be marked as switch tube Q8, main switch tube 2 can be marked switch tube Q9, and secondary inductance 7 can be marked as L2.

[0014] In the embodiment, the full-bridge LLC bridge arm mentioned contains the first switch tube 4, the second switch tube 3 and the diode D1, the first switch tube 4 is connected together with the second switch tube 3, and the common connection end of the first switch tube 4 and the second switch tube 3 is connected with the primary inductance 1, and the diode D1 is connected in parallel across the second switch tube 3; the first switch tube 4 can be marked as switch tube Q1, the second switch tube 3 can be marked as switch tube Q2, and the primary inductance 1 can be marked as L1.

[0015] The improved topology based on the BOOST and LLC power topology. Taking the 270V input voltage scenario as an example, the DC / DC converter should be able to output rated power of 6kW in the input voltage range of 200V-330V, and should have the ability of 1.5 times overload and twice overload. Compared with the traditional BOOST+full-bridge LLC power topology architecture, the power devices of the two-stage converter should be selected and the magnetic components should be designed according to twice the rated power. In the embodiment, the improved power topology architecture is adopted, and the BOOST circuit is connected to only half of the bridge arm of the full-bridge LLC, i.e. under the rated output power condition, the output power of BOOST is only half of that of the traditional topology architecture. In summary, the BOOST loss is reduced by half, and the power output is reduced by half, so the power devices can be reduced, saving cost, and the inductance weight and volume can be effectively reduced. In the embodiment, the full-bridge LLC converter control still adopts the traditional PFM control, and there is no special control requirement. The BOOST circuit control is changed, which mainly includes two working modes: when the output input voltage is higher than 270V, the switch tube Q9 is turned on; the converter only works in full-bridge LLC; when the output voltage is lower than 265V, the switch tube Q9 is turned off, and the BOOST circuit starts to work, and the average value of the BOOST input voltage and the output voltage is always kept around 265V. In this way, the gain of the full-bridge LLC resonant cavity can be guaranteed, and the stability of the output voltage of the DC / DC converter under low input voltage condition can be ensured.

[0016] In summary, the improved topology based on the BOOST and LLC power topology improves the upper limit of the two-stage power topology architecture by improving the circuit structure from the power topology angle. The theoretical efficiency of the improved topology in the embodiment is improved by about 0.3%-0.5% compared with the traditional topology for the DC / DC converter with power above 1kW. The improved topology based on the BOOST and LLC power topology has obvious improvement in efficiency index, and the output power of the BOOST circuit is reduced by half, which significantly reduces the weight and volume of the DC / DC converter.

[0017] The technical features of the above embodiments can be combined arbitrarily. In order to make the description simple, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present disclosure.

[0018] The above examples only express the preferred embodiments of the utility model, the description is more specific and detailed, but can not therefore be understood as the restriction of the utility model patent scope; it should be pointed out that for ordinary skilled person in the art, under the premise of not departing from the utility model concept, still can make several deformation and improvement, these all belong to the protection scope of the utility model; in the utility model, unless another explicit provision and limitation, the term "installation", "link", "connection", "fix" and so on term should do broad sense understanding, for example, can be fixed connection, also can be detachable connection, or integrated; can be mechanical connection; can be direct connection, also can pass through intermediate medium indirectly connect, can be two element inside's intercommunication or two element's interaction relationship.

[0019] Although the embodiments of the utility model have been shown and described, for ordinary skilled person in the art, can understand that these embodiments can be changed, modified, replaced and changed in multiple ways without departing from the principles and spirits of the utility model, the scope of the utility model is defined by the appended claims and its equivalents.

Claims

1. An improved topology based on BOOST and LLC power topology, characterized in that: The application relates to a switching circuit, a full-bridge LLC bridge arm and a main switch tube connected in parallel with the input end of the switching circuit, and a No. 1 inductor connected with the full-bridge LLC bridge arm, wherein the output end of the switching circuit is connected with a transformer through a first filter capacitor and a No. 2 inductor, the secondary side of the transformer is connected in parallel with a switch tube assembly and a third filter capacitor, the input end of the main switch tube, the No. 1 inductor and the full-bridge LLC bridge arm is connected with an output input voltage.

2. The improved topology based on the BOOST and LLC power topology of claim 1, wherein: The switching circuit is composed of a switch tube Q3, a switch tube Q4, a switch tube Q5 and a switch tube Q6, the switch tube Q5 and the switch tube Q6 are connected together, the switch tube Q3 and the switch tube Q4 are connected together, and a capacitor C2 is connected in parallel between the free ends of the switch tube Q3 and the switch tube Q4.

3. The improved topology based on the BOOST and LLC power topology of claim 1, wherein: The full-bridge LLC bridge arm comprises a first switch tube, a second switch tube and a diode D1, the first switch tube and the second switch tube are connected together, the common connection end of the first switch tube and the second switch tube is connected with the No. 1 inductor, and the diode D1 is connected in parallel across the second switch tube.

4. The improved topology based on the BOOST and LLC power topology of claim 1, wherein: The switch tube assembly is composed of a third switch tube and a fourth switch tube, the input ends of the third switch tube and the fourth switch tube are connected at the position of the secondary side of the transformer.

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