CN210780553U - Bidirectional DC-DC converter based on LLC resonance - Google Patents
Bidirectional DC-DC converter based on LLC resonance Download PDFInfo
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- CN210780553U CN210780553U CN201921422444.9U CN201921422444U CN210780553U CN 210780553 U CN210780553 U CN 210780553U CN 201921422444 U CN201921422444 U CN 201921422444U CN 210780553 U CN210780553 U CN 210780553U
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Abstract
The embodiment of the utility model discloses a two-way DC-DC converter based on LLC resonance, which comprises a high-pressure side bridge circuit unit, a resonance network unit, a transformer unit and a low-pressure side bridge circuit unit; the resonant network unit comprises a first path and a second path, and is respectively provided with a first switch unit and a second switch unit; one end of the high-voltage side bridge type circuit unit is connected with the high-voltage end, and the other end of the high-voltage side bridge type circuit unit is connected with one end of the resonant network unit; the other end of the resonant network unit is connected with the primary side of the transformer unit; the secondary side of the transformer unit is connected with one end of the low-voltage side bridge type circuit unit; the other end of the low-voltage side bridge circuit unit is connected with the low-voltage end. In the embodiment, one path is selected by the two switch units to participate in resonance, and the path which does not participate in resonance does not generate extra current so as to avoid additional loss.
Description
Technical Field
The utility model relates to a power electronics technical field especially relates to a two-way DC-DC converter based on LLC resonance.
Background
At present, a bidirectional DC-DC converter is a typical one-machine multi-purpose device and is widely applied to micro-grids, photovoltaics and energy storage systems. With the development of technology, higher requirements are put on a bidirectional DC-DC converter, and the most important requirement is the improvement of efficiency. The technology of the bidirectional DC-DC converter represented by full-bridge phase shift is mature gradually, but the technology also has more and more disadvantages, wherein the harsh implementation condition of the soft switch is the main short board of the converter.
An LLC resonant high-transformation-ratio high-power bidirectional DCDC converter with publication number CN206180852U is shown in FIG. 1, the topological form of the converter is LLLC, LLC resonance occurs during operation, and when current flows from a low-voltage side to a high-voltage side, an inductor Lr, an inductor Lm and a capacitor Cr resonate, so that zero-voltage switching-on of switching tubes S1-S4 and zero-current switching-on and zero-current switching-off of switching tubes S5-S8 are realized; when current flows from the high-voltage side to the low-voltage side, the inductor Lr, the inductor Lm2 and the capacitor Cr resonate, so that zero-voltage switching-on of the switching tubes S5-S8 and zero-current switching-on and zero-current switching-off of the switching tubes S1-S4 are realized. This leads to the following disadvantages:
1) when current flows from the low-voltage side to the high-voltage side, the inductor Lm2 does not participate in resonance, but additionally generates current to form additional loss; on the same principle, when the current flows from the high-voltage side to the low-voltage side, Lm does not participate in resonance, and additional loss is formed;
2) the devices Lr, Lm2, Cr of the resonant tank circuit are disposed on the low voltage side, and the current flowing through the resonant device is larger than when the resonant device is placed on the high voltage side, and the resonator device generates more heat and generates more loss.
SUMMERY OF THE UTILITY MODEL
An embodiment of the utility model provides a two-way DC-DC converter based on LLC resonance aims at solving and has the great problem of loss that the resonance device generates heat among the high-power two-way DCDC converter of current high transformation ratio.
On the one hand, the utility model provides a two-way DC-DC converter based on LLC resonance, this two-way DC-DC converter based on LLC resonance includes high pressure side bridge circuit unit, resonant network unit, transformer unit and low pressure side bridge circuit unit; the resonant network unit comprises a first path and a second path, wherein the first path is provided with a first switch unit, and the second path is provided with a second switch unit;
one end of the high-voltage side bridge circuit unit is connected with a high-voltage end, and the other end of the high-voltage side bridge circuit unit is connected with one end of the resonant network unit;
the other end of the resonant network unit is connected with the primary side of the transformer unit;
the secondary side of the transformer unit is connected with one end of the low-voltage side bridge type circuit unit;
the other end of the low-voltage side bridge circuit unit is connected with a low-voltage end;
the high-voltage side bridge circuit unit is used for converting direct current at a high-voltage end into alternating current;
the resonance network unit is used for keeping the voltage of the alternating current output by the high-voltage side bridge circuit unit constant to obtain constant voltage;
the transformer unit is used for reducing the constant voltage output by the resonant network unit to obtain reduced voltage alternating current;
and the low-voltage side bridge type circuit unit is used for converting the step-down alternating current to obtain step-down direct current.
In the bidirectional DC-DC converter based on LLC resonance of the present invention, the first switch unit is turned off when current flows from the high-voltage end to the low-voltage end, and the second switch unit is turned on when current flows from the high-voltage end to the low-voltage end;
the first switch unit is switched on when current flows from the low-voltage end to the high-voltage end, and the second switch unit is switched off when current flows from the low-voltage end to the high-voltage end.
In the bidirectional DC-DC converter based on LLC resonance of the present invention, the resonant network unit includes a first inductor, a second inductor, a third inductor, and a first capacitor; the first switch unit is a first four-quadrant switch; the second switch unit is a second four-quadrant switch; the first inductor, the second inductor, the first four-quadrant switch and the first capacitor form a first path of the resonant network unit; the first inductor, the third inductor, the second four-quadrant switch and the first capacitor form a second path of the resonant network unit;
one end of the first inductor is connected with the high-voltage side bridge circuit unit, and the other end of the first inductor is connected with the primary side of the transformer unit;
one end of the second inductor is connected with the high-voltage side bridge circuit unit, and the other end of the second inductor is connected with one end of the first four-quadrant switch;
one end of the third inductor is connected with the primary side of the transformer unit, and the other end of the third inductor is connected with one end of the second four-quadrant switch;
the other end of the first four-quadrant switch is connected with the high-voltage side bridge type circuit unit;
the other end of the second four-quadrant switch is connected with the primary side of the transformer unit;
one end of the first capacitor is connected with the high-voltage side bridge type circuit unit, and the other end of the first capacitor is connected with the primary side of the transformer unit.
In the bidirectional DC-DC converter based on LLC resonance of the present invention, the first four-quadrant switch includes a first MOS transistor, a second MOS transistor, and a first relay;
the grid electrode of the first MOS tube is connected with the grid electrode of the second MOS tube, the source electrode of the first MOS tube is connected with one end of the first capacitor, and the drain electrode of the first MOS tube is connected with the source electrode of the second MOS tube;
the drain electrode of the second MOS tube is connected with one end of the second inductor;
one end of the first relay is connected with the source electrode of the first MOS tube, and the other end of the first relay is connected with the drain electrode of the second MOS tube.
In the bidirectional DC-DC converter based on LLC resonance of the present invention, the second four-quadrant switch includes a third MOS transistor, a fourth MOS transistor, and a second relay;
the grid electrode of the third MOS tube is connected with the grid electrode of the fourth MOS tube, the source electrode of the third MOS tube is connected with one end of the first capacitor, and the drain electrode of the third MOS tube is connected with the source electrode of the fourth MOS tube;
the drain electrode of the fourth MOS tube is connected with one end of the third inductor;
one end of the second relay is connected with the source electrode of the third MOS tube, and the other end of the second relay is connected with the drain electrode of the fourth MOS tube.
In the bidirectional DC-DC converter based on LLC resonance of the present invention, the high-side bridge circuit unit includes a first switch tube, a second switch tube, a third switch tube, and a fourth switch tube;
one end of the first switch tube is connected with the high-voltage end, and the other end of the first switch tube is connected with one end of the second switch tube;
the other end of the second switch tube is connected with the high-voltage end; the first switching tube and the second switching tube are connected in series to form a first bridge arm, and the middle point of the first bridge arm is a first network point; the first network point is connected with one end of the first inductor;
one end of the third switching tube is connected with the high-voltage end, and the other end of the third switching tube is connected with one end of the fourth switching tube;
the other end of the fourth switching tube is connected with the high-voltage end; the third switching tube and the fourth switching tube are connected in series to form a second bridge arm, and the middle point of the second bridge arm is a second network point; the second network point is connected with one end of the first capacitor.
In the bidirectional DC-DC converter based on LLC resonance of the present invention, the low-voltage side bridge circuit unit includes a fifth switching tube, a sixth switching tube, a seventh switching tube, and an eighth switching tube;
one end of the fifth switching tube is connected with the low-voltage end, and the other end of the fifth switching tube is connected with one end of the sixth switching tube;
the other end of the sixth switching tube is connected with the low-voltage end; the fifth switching tube and the sixth switching tube are connected in series to form a third bridge arm, and the middle point of the third bridge arm is a third network point; the third network point is connected with the secondary side of the transformer unit;
one end of the seventh switching tube is connected with the low-voltage end, and the other end of the seventh switching tube is connected with one end of the eighth switching tube;
the other end of the eighth switching tube is connected with the low-voltage end; the seventh switching tube and the eighth switching tube are connected in series to form a fourth bridge arm, and the middle point of the fourth bridge arm is a fourth network point; the fourth network point is connected to the secondary side of the transformer unit.
In the bidirectional DC-DC converter based on LLC resonance of the present invention, the low-voltage side bridge circuit unit includes a fifth switching tube, a sixth switching tube, a second capacitor, and a third capacitor;
one end of the fifth switching tube is connected with the low-voltage end, and the other end of the fifth switching tube is connected with one end of the sixth switching tube;
the other end of the sixth switching tube is connected with the low-voltage end; the fifth switching tube and the sixth switching tube are connected in series to form a third bridge arm, and the middle point of the third bridge arm is a third network point; the third network point is connected with the secondary side of the transformer unit;
one end of the second capacitor is connected with the low-voltage end, and the other end of the second capacitor is connected with one end of the third capacitor;
the other end of the third capacitor is connected with the low-voltage end; the second capacitor and the third capacitor are connected in series to form a fourth bridge arm, and the middle point of the fourth bridge arm is a fourth network point; the fourth network point is connected to the secondary side of the transformer unit.
In the bidirectional DC-DC converter based on LLC resonance of the present invention, the high-voltage side is also connected to a fourth capacitor; and the low-voltage end is also connected with a fifth capacitor.
In the bidirectional DC-DC converter based on LLC resonance, the excitation inductance in the transformer unit is the inductance processed through the air gap process.
An embodiment of the utility model provides a two-way DC-DC converter based on LLC resonance sets up the resonant network unit in the high-pressure side, moreover the resonant network unit includes first route and second route, first route is provided with first switch unit, be provided with second switch unit on the second route, two above-mentioned switch units of accessible select one of them route to participate in the resonance, do not participate in the resonance not additionally produce electric current and avoid the additional loss all the way. And the resonant network unit is located the high-voltage end, makes the electric current that flows through the resonant network unit reduce to reduce and generate heat, and then reduce energy loss.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without any creative effort.
FIG. 1 is a schematic diagram of a circuit structure of a high-ratio high-power bidirectional DCDC converter with LLC resonance in the prior art;
fig. 2 is a schematic structural diagram of a bidirectional DC-DC converter based on LLC resonance according to an embodiment of the present invention;
fig. 3 is a schematic circuit structure diagram of a bidirectional DC-DC converter based on LLC resonance according to an embodiment of the present invention;
fig. 4 is a schematic circuit structure diagram of a first four-quadrant switch in a bidirectional DC-DC converter based on LLC resonance according to an embodiment of the present invention;
fig. 5 is a schematic circuit structure diagram of a second four-quadrant switch in the bidirectional DC-DC converter based on LLC resonance according to an embodiment of the present invention;
fig. 6 is a schematic circuit diagram of a bidirectional DC-DC converter based on LLC resonance according to another embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, of the embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Referring to fig. 2 and fig. 3, fig. 2 is a schematic structural diagram of a bidirectional DC-DC converter based on LLC resonance according to an embodiment of the present invention; fig. 3 is a schematic circuit structure diagram of a bidirectional DC-DC converter based on LLC resonance according to an embodiment of the present invention. As shown in fig. 2 and 3, the bidirectional DC-DC converter based on LLC resonance includes: a high-voltage side bridge circuit unit 11, a resonant network unit 12, a transformer unit 13, and a low-voltage side bridge circuit unit 14; the resonant network unit 12 includes a first path and a second path, the first path is provided with a first switch unit, and the second path is provided with a second switch unit;
one end of the high-voltage side bridge circuit unit 11 is connected with the high-voltage end 10, and the other end of the high-voltage side bridge circuit unit 11 is connected with one end of the resonant network unit 12;
the other end of the resonant network unit 12 is connected with one end of the transformer unit 13;
the other end of the transformer unit 13 is connected with one end of the low-voltage side bridge circuit unit 14;
the other end of the low-voltage side bridge circuit unit 14 is connected with a low-voltage end 15;
the high-voltage side bridge circuit unit 11 is used for converting direct current at a high-voltage end into alternating current;
a resonant network unit 12, configured to make a voltage of the alternating current output by the high-voltage side bridge circuit unit 11 constant to obtain a constant voltage;
the transformer unit 13 is used for reducing the constant voltage output by the resonant network unit 12 to obtain reduced-voltage alternating current;
and the low-voltage side bridge circuit unit 14 is used for converting the step-down alternating current to obtain step-down direct current.
Wherein, the resonant network unit 12 is arranged at the high-voltage side of the transformer unit 13, and according to the transformer equivalence principle, the transformation ratio of the transformer is n, and then the ratio of the high-voltage side circuit current to the low-voltage side circuit current is 1: n, under the condition that the frequency of the resonant circuit (namely the resonant network unit 12) is fixed, the capacitance values of the resonant inductance and the resonant capacitance are determined; when the resonant circuit is arranged on the high-voltage side, the current flowing through the resonant inductor and the resonant capacitor is only one n times that of the resonant circuit arranged on the low-voltage side, and the loss of the resonant circuit is also obviously reduced.
In addition, one of the two switch units respectively arranged on the two paths of the resonant network unit 12 is selected to participate in resonance, and the path which does not participate in resonance does not additionally generate current so as to avoid additional loss, so that the bidirectional DC-DC converter based on LLC resonance can realize soft switching in any direction.
Specifically, the first switch unit is turned off when current flows from the high-voltage end 10 to the low-voltage end 15, and the second switch unit is turned on when current flows from the high-voltage end 10 to the low-voltage end 15;
the first switch unit is turned on when current flows from the low voltage terminal 15 to the high voltage terminal 10, and the second switch unit is turned off when current flows from the low voltage terminal 15 to the high voltage terminal 10.
When the current flows from the high-voltage end 10 to the low-voltage end 15, the first switch unit is turned off, the second switch unit is turned on, only the second path of the first path and the second path included in the resonant network unit 12 is turned on, and the inductance element on the first path is separated from the loop circuit because the first path is not turned on, so that the loss caused by the current generated by the inductance can be reduced. When the current flows from the low-voltage end 15 to the high-voltage end 10, the first switch unit is turned on, the second switch unit is turned off, only the first path is turned on from the first path and the second path included in the resonant network unit 12, and the second path is separated from the loop circuit due to the fact that the inductive element on the second path is not turned on, so that loss caused by the current generated by the inductor can be reduced.
Referring to fig. 3, fig. 3 is a schematic circuit structure diagram of a bidirectional DC-DC converter based on LLC resonance according to an embodiment of the present invention. Specifically, as shown in fig. 3, the resonant network unit 12 includes a first inductor Lr, a second inductor Lm2, a third inductor Lm, a first capacitor Cr; the first switch unit is a first four-quadrant switch Q9; the second switch unit is a second four-quadrant switch Q10; the first inductor Lr, the second inductor Lm2, the first four-quadrant switch Q9, and the first capacitor Cr form a first path of the resonant network unit 12; the first inductor Lr, the third inductor Lm, the second four-quadrant switch Q10, and the first capacitor Cr form a second path of the resonant network unit 12;
one end of the first inductor Lr is connected to the high-voltage side bridge circuit unit 11, and the other end of the first inductor Lr is connected to the primary side of the transformer unit 13;
one end of the second inductor Lm2 is connected to the high-voltage bridge circuit unit 11, and the other end of the second inductor Lm2 is connected to one end of the first four-quadrant switch Q9;
one end of the third inductor Lm is connected to the primary side of the transformer unit 13, and the other end of the third inductor Lm is connected to one end of the second four-quadrant switch Q10;
the other end of the first four-quadrant switch Q9 is connected to the high-side bridge circuit unit 11;
the other end of the second four-quadrant switch Q10 is connected to the primary side of the transformer unit 13;
one end of the first capacitor Cr is connected to the high-voltage side bridge circuit unit 11, and the other end is connected to the primary side of the transformer unit 13.
Wherein, a four-quadrant switch is respectively arranged on the first path and the second path of the resonant network unit 12, and the LLLC resonant circuit topology with two four-quadrant switching tubes is different from the prior art in that:
(1) the particularity of the position of the four-quadrant switch;
(2) the four-quadrant switch can quickly play, is different from the prior art, and cannot bring the problem of current direction switching speed.
Referring to fig. 3 and fig. 4, fig. 4 is a schematic circuit structure diagram of a first four-quadrant switch in a bidirectional DC-DC converter based on LLC resonance according to an embodiment of the present invention. Specifically, as shown in fig. 3 and 4, the first four-quadrant switch Q9 includes a first MOS transistor Q11, a second MOS transistor Q12, and a first relay D1;
the gate of the first MOS transistor Q11 is connected to the gate of the second MOS transistor Q12, the source of the first MOS transistor Q11 is connected to one end of the first capacitor Cr, and the drain of the first MOS transistor Q11 is connected to the source of the second MOS transistor Q12;
the drain of the second MOS transistor Q12 is connected to one end of the second inductor Lm 2;
one end of the first relay D1 is connected to the source of the first MOS transistor Q11, and the other end of the first relay D1 is connected to the drain of the second MOS transistor Q12.
One of the first four-quadrant switch Q9 has a circuit structure as shown in fig. 4, the first four-quadrant switch Q9 is composed of two MOS transistors and a relay, that is, a semiconductor device and the relay are connected in parallel, so that the on/off speed is high, and the four-quadrant on/off of current and voltage can be realized. The first four-quadrant switch Q9 also has the following features: firstly, the switching-on speed of an MOS transistor is close to that of a bridge circuit switching tube; and secondly, the relay is connected in parallel, so that the loss generated by the on-resistance of the MOS tube is reduced.
Referring to fig. 3 and fig. 5, fig. 5 is a schematic circuit structure diagram of a second four-quadrant switch in a bidirectional DC-DC converter based on LLC resonance according to an embodiment of the present invention. Specifically, as shown in fig. 3 and 5, the second four-quadrant switch Q10 includes a third MOS transistor Q13, a fourth MOS transistor Q14, and a second relay D2;
the gate of the third MOS transistor Q13 is connected to the gate of the fourth MOS transistor Q14, the source of the third MOS transistor Q13 is connected to one end of the first capacitor Cr, and the drain of the third MOS transistor Q13 is connected to the source of the fourth MOS transistor Q14;
the drain of the fourth MOS transistor Q14 is connected to one end of the third inductor Lm;
one end of the second relay D2 is connected to the source of the third MOS transistor Q13, and the other end of the second relay D2 is connected to the drain of the fourth MOS transistor Q14.
The circuit structure of the second four-quadrant switch Q10 is identical to that of the first four-quadrant switch Q9, and the beneficial effects achieved by the same.
Specifically, as shown in fig. 3, the high-side bridge circuit unit 11 includes a first switch Q1, a second switch Q2, a third switch Q3, and a fourth switch Q4;
one end of the first switch tube Q1 is connected to the high voltage terminal 10, and the other end of the first switch tube Q1 is connected to one end of the second switch tube Q2;
the other end of the second switching tube Q2 is connected with the high-voltage end 10; the first switch tube Q1 and the second switch tube Q2 are connected in series to form a first bridge arm, and the middle point of the first bridge arm is a first network point P1; the first network point P1 is connected to one end of the first inductor Lr;
one end of the third switching tube Q3 is connected to the high voltage terminal 10, and the other end of the third switching tube Q3 is connected to one end of the fourth switching tube Q4;
the other end of the fourth switching tube Q4 is connected with the high-voltage end 10; the third switching tube Q3 and the fourth switching tube Q4 are connected in series to form a second bridge arm, and the middle point of the second bridge arm is a second network point P2; the second network point P2 is connected to one end of the first capacitor Cr.
The high-voltage side bridge circuit unit 11 is configured to have the above-mentioned circuit structure including 4 switching tubes, so that direct current at the high-voltage side 11 can be effectively converted into alternating current to realize preliminary DC-AC conversion. The alternating current converted by the high-voltage side bridge circuit unit 11 is input to the resonant network unit 12 to be constant to obtain a constant voltage.
When the current flows from the HIGH-voltage end 10 to the low-voltage end 15, a square wave with the amplitude of V _ HIGH and the duty ratio of 50% exists between points P1 and P2, the Q9 is turned off, the Q10 is turned on, the second inductor Lm2 is separated from a loop, and the loss caused by the current generated by the Lm2 can be reduced. Similarly, when the current flows from the low-voltage side to the high-voltage side, the turn-off Q10 turns on the Q9, and the loss caused by the current generated by the third inductor Lm can be reduced.
Specifically, as shown in fig. 3, as a first embodiment of the bidirectional DC-DC converter based on LLC resonance, the low-side bridge circuit unit 14 includes a fifth switching tube Q5, a sixth switching tube Q6, a seventh switching tube Q7, and an eighth switching tube Q8;
one end of the fifth switching tube Q5 is connected to the low voltage terminal 15, and the other end of the fifth switching tube Q5 is connected to one end of the sixth switching tube Q6;
the other end of the sixth switching tube Q6 is connected to the low voltage terminal 15; the fifth switching tube Q5 and the sixth switching tube Q6 are connected in series to form a third bridge arm, and the middle point of the third bridge arm is a third network point P3; the third network point P3 is connected to the secondary side of the transformer unit 13;
one end of the seventh switch tube Q7 is connected to the low voltage terminal 15, and the other end of the seventh switch tube Q7 is connected to one end of the eighth switch tube Q8;
the other end of the eighth switching tube Q8 is connected to the low voltage terminal 15; the seventh switching tube Q7 and the eighth switching tube Q8 are connected in series to form a fourth bridge arm, and the middle point of the fourth bridge arm is a fourth network point P4; the fourth network point P4 is connected to the secondary side of the transformer unit 13.
The low-voltage side bridge circuit unit 14 is configured to have the above-mentioned circuit structure including 4 switching tubes, so that the step-down AC output from the transformer unit 13 can be effectively converted into step-down DC and output from the low-voltage terminal 15, so as to implement final AC-DC conversion.
Specifically, as shown in fig. 6, as a second embodiment of the bidirectional DC-DC converter based on LLC resonance, the low-side bridge circuit unit 14 includes a fifth switch Q5, a sixth switch Q6, a second capacitor C3, and a third capacitor C4;
one end of the fifth switching tube Q5 is connected to the low voltage terminal 15, and the other end of the fifth switching tube Q5 is connected to one end of the sixth switching tube Q6;
the other end of the sixth switching tube Q6 is connected to the low voltage terminal 15; the fifth switching tube Q5 and the sixth switching tube Q6 are connected in series to form a third bridge arm, and the middle point of the third bridge arm is a third network point P3; the third network point P3 is connected to the secondary side of the transformer unit 13;
one end of the second capacitor C3 is connected with the low voltage end 15, and the other end of the second capacitor C3 is connected with one end of the third capacitor C4;
the other end of the third capacitor C4 is connected with the low-voltage end 15; the second capacitor C3 and the third capacitor C4 are connected in series to form a fourth bridge arm, and the middle point of the fourth bridge arm is a fourth network point P4; the fourth network point P4 is connected to the secondary side of the transformer unit 13.
In the second embodiment of the bidirectional DC-DC converter based on LLC resonance, the difference from the first embodiment is that the second capacitor C3 is connected in series with the third capacitor C4 to form the fourth leg. That is, in the first embodiment of the bidirectional DC-DC converter based on LLC resonance, each of the four legs of the first leg to the fourth leg consists of two switching tubes. In the second embodiment, each of the three first to third arms is composed of two switching tubes, and the fourth arm is composed of two capacitors. In the specific implementation, in addition to the two embodiments, the following embodiments are also provided:
in the third embodiment, the first bridge arm, the third bridge arm and the fourth bridge arm are all composed of two switching tubes, and the second bridge arm is composed of two capacitors.
In the fourth embodiment, the second bridge arm, the third bridge arm and the fourth bridge arm are all composed of two switching tubes, and the first bridge arm is composed of two capacitors.
In the fifth embodiment, the first bridge arm, the second bridge arm and the fourth bridge arm are all composed of two switching tubes, and the third bridge arm is composed of two capacitors.
In the sixth embodiment, the first bridge arm and the third bridge arm are both composed of two switching tubes, and the second bridge arm and the fourth bridge arm are both composed of two capacitors.
In the seventh embodiment, the second bridge arm and the fourth bridge arm are both composed of two switching tubes, and the first bridge arm and the third bridge arm are both composed of two capacitors.
Wherein, the first embodiment is suitable for high-power occasions; the second embodiment to the seventh embodiment are suitable for a low power occasion to reduce the product cost.
Specifically, as shown in fig. 3, the high voltage terminal 10 is further connected to a fourth capacitor C1; the low voltage terminal 15 is also connected to a fifth capacitor C2.
The high-voltage terminal 10 and the low-voltage terminal 15 are both connected to a capacitor for filtering to filter the noise interference to the circuit.
Specifically, the excitation inductance in the transformer unit 15 is an inductance processed by an air gap process.
The excitation inductance in the transformer unit 15 is designed to approach 0 by using an air gap process, so that the transformation effect is improved.
It can be seen that, in this embodiment, the resonant network unit is disposed on the high-voltage side, and the resonant network unit includes a first path and a second path, where the first path is provided with a first switch unit, and the second path is provided with a second switch unit, and one of the paths can be selected by the two switch units to participate in resonance, and one of the paths that does not participate in resonance does not generate extra current, so as to avoid additional loss. And the resonant network unit is located the high-voltage end, makes the electric current that flows through the resonant network unit reduce to reduce and generate heat, and then reduce energy loss.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope of the present invention, and these modifications or replacements should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A bidirectional DC-DC converter based on LLC resonance is characterized by comprising a high-voltage side bridge circuit unit, a resonance network unit, a transformer unit and a low-voltage side bridge circuit unit; the resonant network unit comprises a first path and a second path, wherein the first path is provided with a first switch unit, and the second path is provided with a second switch unit;
one end of the high-voltage side bridge circuit unit is connected with a high-voltage end, and the other end of the high-voltage side bridge circuit unit is connected with one end of the resonant network unit;
the other end of the resonant network unit is connected with the primary side of the transformer unit;
the secondary side of the transformer unit is connected with one end of the low-voltage side bridge type circuit unit;
the other end of the low-voltage side bridge circuit unit is connected with a low-voltage end;
the high-voltage side bridge circuit unit is used for converting direct current at a high-voltage end into alternating current;
the resonance network unit is used for keeping the voltage of the alternating current output by the high-voltage side bridge circuit unit constant to obtain constant voltage;
the transformer unit is used for reducing the constant voltage output by the resonant network unit to obtain reduced voltage alternating current;
and the low-voltage side bridge type circuit unit is used for converting the step-down alternating current to obtain step-down direct current.
2. The LLC resonance based bidirectional DC-DC converter according to claim 1, wherein said first switching unit is turned off when current flows from said high voltage side to said low voltage side, and said second switching unit is turned on when current flows from said high voltage side to said low voltage side;
the first switch unit is switched on when current flows from the low-voltage end to the high-voltage end, and the second switch unit is switched off when current flows from the low-voltage end to the high-voltage end.
3. The LLC resonance-based bidirectional DC-DC converter of claim 1, wherein said resonant network unit includes a first inductor, a second inductor, a third inductor, a first capacitor; the first switch unit is a first four-quadrant switch; the second switch unit is a second four-quadrant switch; the first inductor, the second inductor, the first four-quadrant switch and the first capacitor form a first path of the resonant network unit; the first inductor, the third inductor, the second four-quadrant switch and the first capacitor form a second path of the resonant network unit;
one end of the first inductor is connected with the high-voltage side bridge circuit unit, and the other end of the first inductor is connected with the primary side of the transformer unit;
one end of the second inductor is connected with the high-voltage side bridge circuit unit, and the other end of the second inductor is connected with one end of the first four-quadrant switch;
one end of the third inductor is connected with the primary side of the transformer unit, and the other end of the third inductor is connected with one end of the second four-quadrant switch;
the other end of the first four-quadrant switch is connected with the high-voltage side bridge type circuit unit;
the other end of the second four-quadrant switch is connected with the primary side of the transformer unit;
one end of the first capacitor is connected with the high-voltage side bridge type circuit unit, and the other end of the first capacitor is connected with the primary side of the transformer unit.
4. The LLC resonance based bidirectional DC-DC converter according to claim 3, wherein said first four quadrant switch comprises a first MOS transistor, a second MOS transistor, a first relay;
the grid electrode of the first MOS tube is connected with the grid electrode of the second MOS tube, the source electrode of the first MOS tube is connected with one end of the first capacitor, and the drain electrode of the first MOS tube is connected with the source electrode of the second MOS tube;
the drain electrode of the second MOS tube is connected with one end of the second inductor;
one end of the first relay is connected with the source electrode of the first MOS tube, and the other end of the first relay is connected with the drain electrode of the second MOS tube.
5. The LLC resonance based bidirectional DC-DC converter according to claim 4, wherein said second four quadrant switch comprises a third MOS transistor, a fourth MOS transistor, a second relay;
the grid electrode of the third MOS tube is connected with the grid electrode of the fourth MOS tube, the source electrode of the third MOS tube is connected with one end of the first capacitor, and the drain electrode of the third MOS tube is connected with the source electrode of the fourth MOS tube;
the drain electrode of the fourth MOS tube is connected with one end of the third inductor;
one end of the second relay is connected with the source electrode of the third MOS tube, and the other end of the second relay is connected with the drain electrode of the fourth MOS tube.
6. The LLC resonance based bidirectional DC-DC converter as claimed in claim 3, wherein said high side bridge circuit unit comprises a first switch tube, a second switch tube, a third switch tube, a fourth switch tube;
one end of the first switch tube is connected with the high-voltage end, and the other end of the first switch tube is connected with one end of the second switch tube;
the other end of the second switch tube is connected with the high-voltage end; the first switching tube and the second switching tube are connected in series to form a first bridge arm, and the middle point of the first bridge arm is a first network point; the first network point is connected with one end of the first inductor;
one end of the third switching tube is connected with the high-voltage end, and the other end of the third switching tube is connected with one end of the fourth switching tube;
the other end of the fourth switching tube is connected with the high-voltage end; the third switching tube and the fourth switching tube are connected in series to form a second bridge arm, and the middle point of the second bridge arm is a second network point; the second network point is connected with one end of the first capacitor.
7. The LLC resonance-based bidirectional DC-DC converter according to claim 6, wherein said low side bridge circuit unit comprises a fifth switching tube, a sixth switching tube, a seventh switching tube, an eighth switching tube;
one end of the fifth switching tube is connected with the low-voltage end, and the other end of the fifth switching tube is connected with one end of the sixth switching tube;
the other end of the sixth switching tube is connected with the low-voltage end; the fifth switching tube and the sixth switching tube are connected in series to form a third bridge arm, and the middle point of the third bridge arm is a third network point; the third network point is connected with the secondary side of the transformer unit;
one end of the seventh switching tube is connected with the low-voltage end, and the other end of the seventh switching tube is connected with one end of the eighth switching tube;
the other end of the eighth switching tube is connected with the low-voltage end; the seventh switching tube and the eighth switching tube are connected in series to form a fourth bridge arm, and the middle point of the fourth bridge arm is a fourth network point; the fourth network point is connected to the secondary side of the transformer unit.
8. The LLC resonance-based bidirectional DC-DC converter according to claim 6, wherein said low side bridge circuit unit comprises a fifth switching tube, a sixth switching tube, a second capacitor, a third capacitor;
one end of the fifth switching tube is connected with the low-voltage end, and the other end of the fifth switching tube is connected with one end of the sixth switching tube;
the other end of the sixth switching tube is connected with the low-voltage end; the fifth switching tube and the sixth switching tube are connected in series to form a third bridge arm, and the middle point of the third bridge arm is a third network point; the third network point is connected with the secondary side of the transformer unit;
one end of the second capacitor is connected with the low-voltage end, and the other end of the second capacitor is connected with one end of the third capacitor;
the other end of the third capacitor is connected with the low-voltage end; the second capacitor and the third capacitor are connected in series to form a fourth bridge arm, and the middle point of the fourth bridge arm is a fourth network point; the fourth network point is connected to the secondary side of the transformer unit.
9. The LLC resonance-based bidirectional DC-DC converter according to claim 1, wherein said high voltage terminal is further connected to a fourth capacitor; and the low-voltage end is also connected with a fifth capacitor.
10. The LLC resonance-based bidirectional DC-DC converter as claimed in any one of claims 1-9, wherein the excitation inductance in said transformer unit is an inductance processed by an air gap process.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2023221212A1 (en) * | 2022-05-18 | 2023-11-23 | 深圳深源技术能源有限公司 | High-frequency isolated bidirectional converter |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2023221212A1 (en) * | 2022-05-18 | 2023-11-23 | 深圳深源技术能源有限公司 | High-frequency isolated bidirectional converter |
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