CN117767762A - Automatic two-way DCDC circuit that flow equalizes - Google Patents
Automatic two-way DCDC circuit that flow equalizes Download PDFInfo
- Publication number
- CN117767762A CN117767762A CN202311820681.1A CN202311820681A CN117767762A CN 117767762 A CN117767762 A CN 117767762A CN 202311820681 A CN202311820681 A CN 202311820681A CN 117767762 A CN117767762 A CN 117767762A
- Authority
- CN
- China
- Prior art keywords
- network
- transformer
- resonant
- switch
- switching
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- HEZMWWAKWCSUCB-PHDIDXHHSA-N (3R,4R)-3,4-dihydroxycyclohexa-1,5-diene-1-carboxylic acid Chemical compound O[C@@H]1C=CC(C(O)=O)=C[C@H]1O HEZMWWAKWCSUCB-PHDIDXHHSA-N 0.000 title claims abstract description 45
- 230000005284 excitation Effects 0.000 claims abstract description 69
- 230000002457 bidirectional effect Effects 0.000 claims abstract description 43
- 239000003990 capacitor Substances 0.000 claims description 37
- 238000001914 filtration Methods 0.000 claims 1
- 230000000694 effects Effects 0.000 abstract description 6
- 238000010586 diagram Methods 0.000 description 13
- 230000005669 field effect Effects 0.000 description 6
- 239000000463 material Substances 0.000 description 3
- 229910044991 metal oxide Inorganic materials 0.000 description 3
- 150000004706 metal oxides Chemical class 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000012937 correction Methods 0.000 description 2
- 238000002955 isolation Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- 239000004743 Polypropylene Substances 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- -1 polypropylene Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
Landscapes
- Dc-Dc Converters (AREA)
Abstract
The invention relates to a bidirectional DCDC circuit capable of automatically equalizing current, which comprises: the transformer module is arranged on the independent excitation inductance, the first resonant network and the first switching network on the first side of the transformer module, and the second resonant network, the third switching network and the series-parallel switching network on the second side of the transformer module. According to the invention, the independent excitation inductance is connected in parallel to one side of the transformer module, on one hand, the independent excitation inductance has the same effect as the equivalent excitation inductance of the traditional nonideal transformer, so that the switching frequency variation range is wider, the regulation and control capability is stronger and more accurate, when the LLC circuit works, the peak current flowing through the excitation inductance discharges the junction capacitance of a switching tube in a switching network to be opened to 0 in dead time, zero voltage opening of the LLC circuit is realized, and on the other hand, the automatic current sharing of the first resonant network and the second resonant network in a parallel state can be realized by adding the independent excitation inductance.
Description
Technical Field
The invention relates to the field of new energy, such as an optical storage grid-connected system and a V2G (Vehicle-to-grid) system, in particular to an automatic current sharing bidirectional DCDC circuit.
Background
Energy and environmental problems have become two of the most important issues facing mankind at the present stage. The green and efficient utilization of energy has become the key point of research and application in various countries. With the rapid development of new energy industry at present, the bidirectional power electronic conversion technology is more important. The bidirectional converter is applied to an energy storage system to a great extent, and the impedance of two resonant cavities in a parallel state is inconsistent due to errors of device consistency, production process and the like in the traditional isolation type bidirectional direct current conversion topology, so that the two resonant cavities are not equalized. The current active current sharing method needs to monitor and adjust the working frequency or the duty ratio of each resonant network in real time to realize the same impedance, thereby realizing the relative current sharing, having the defects of low current sharing precision, complex control, poor reliability and the like, and further affecting the performance index and the reliability of the product.
Disclosure of Invention
The invention aims to solve the technical problem that the bidirectional DCDC circuit capable of automatically equalizing current can realize automatic current equalization in a parallel state.
The technical scheme adopted for solving the technical problems is as follows: a bidirectional DCDC circuit for automatic current sharing is constructed, comprising: the transformer module is provided with an independent excitation inductor, a first resonant network and a first switching network which are arranged on a first side of the transformer module, and a second resonant network, a third switching network and a series-parallel switching network which are arranged on a second side of the transformer module;
the first end and the second end of the first switch network are connected with the first end and the second end of the first direct current network, the third end and the fourth end of the first switch network are connected with the first end and the second end of the transformer module through the first resonance network, the independent excitation inductance is connected between the first end and the second end of the transformer module so that the equivalent excitation inductance of the transformer module is connected with the independent excitation inductance in parallel, the third end and the fourth end of the transformer module are connected with the third end and the fourth end of the third switch network through the second resonance network, the first end of the third switch network is connected with the first end of the second direct current network and the first end of the series-parallel switch network, the second end of the third switch network is connected with the second end of the series-parallel switch network, the fifth end and the sixth end of the transformer module are connected with the third end and the fourth end of the fourth switch network through the third resonance network, and the first end of the fourth switch network is connected with the third end of the series-parallel switch network and the fourth end of the series-parallel switch network; when the working direction is from the first direct current network to the second direct current network or from the second direct current network to the first direct current network, the resonance currents of the second resonance network and the third resonance network are equal.
In the automatic current equalizing bidirectional DCDC circuit, the transformer module comprises a first transformer and a second transformer, wherein the first transformer and the second transformer are identical ideal transformers, a first side first end of the first transformer is connected with a first end of the transformer module, a first side second end of the first transformer is connected with a first side first end of the second transformer, and a first side second end of the second transformer is connected with a second end of the transformer module; the independent excitation inductor is connected between a first side first end of the first transformer and a first side second end of the second transformer so as to be connected in parallel with the series excitation inductors of the first transformer and the second transformer; the first end and the second end of the second side of the second transformer are respectively a fifth end and a sixth end of the transformer module.
In the automatic current-sharing bidirectional DCDC circuit, the first resonant network comprises a first resonant inductor and a first resonant capacitor; the first end of the first resonant capacitor is connected with the fourth end of the first switch network, and the second end of the first resonant capacitor is connected with the first side second end of the second transformer.
In the bidirectional DCDC circuit with automatic current sharing, the second resonant network comprises a second resonant inductor and a second resonant capacitor; the first end of the second resonant capacitor is connected with the second end of the second side of the first transformer, and the second end of the second resonant capacitor is connected with the fourth end of the second switch network; the third resonant network comprises a third resonant inductor and a third resonant capacitor; the first end of the third resonant capacitor is connected with the second end of the second side of the second transformer, the second end of the third resonant capacitor is connected with the third end of the third switching network, and the first end of the third resonant capacitor is connected with the second end of the second side of the second transformer, and the second end of the third resonant capacitor is connected with the fourth end of the third switching network.
In the automatic current sharing bidirectional DCDC circuit, the turns ratio of the first transformer to the second transformer is 1: n, wherein N is a positive integer greater than 1; when the working direction is from the first direct current network to the second direct current network, the resonance currents of the second resonance network and the third resonance network are automatically equalized to N times of the first side current of the first transformer; when the working direction is from the second direct current network to the first direct current network, the resonance currents of the second resonance network and the third resonance network are automatically equalized to the sum of the second side current of the first transformer and the equivalent resonance current of the independent excitation inductor on the second side of the first transformer.
In the bidirectional DCDC circuit for automatic current sharing, the series-parallel switching network comprises a first switch, a second switch and a third switch, wherein a fixed contact of the first switch is connected with a second end of the series-parallel switching network, a moving contact of the first switch is connected with a third end of the series-parallel switching network, a fixed contact of the second switch is connected with a first end of the series-parallel switching network, a moving contact of the second switch is connected with a third end of the series-parallel switching network, and a fixed contact of the third switch is connected with a second end of the series-parallel switching network and a moving contact of the third switch is connected with a fourth end of the series-parallel switching network; when the first switch is opened and the second switch and the third switch are closed, the second resonant network and the third resonant network are connected in parallel; when the first switch is closed and the second switch and the third switch are opened, the second resonant network and the third resonant network are connected in series.
In the bidirectional DCDC circuit for automatic current sharing, the first switching network, the second switching network and the third switching network respectively comprise switching tube networks formed by four switching tubes; when the working direction is from the second direct current network to the first direct current network, the switching frequencies of the switching tubes of the second switching network and the third switching network are in the same phase.
In the bidirectional DCDC circuit with automatic current sharing, the invention further comprises a first direct current filter network; the first direct current filter network is connected between the first direct current network and the first switching network.
In the bidirectional DCDC circuit for automatic current sharing according to the present invention, the bidirectional DCDC circuit further includes a second dc filter network and a third dc filter network, wherein the second dc filter network is connected between the second dc network and the second switching network, and the third dc filter network is connected between the second dc network and the third switching network.
According to the invention, the independent excitation inductance is connected in parallel to one side of the transformer module, on one hand, the independent excitation inductance has the same effect as the equivalent excitation inductance of the traditional nonideal transformer, so that the switching frequency variation range is wider, the regulation and control capability is stronger and more accurate, when the LLC circuit works, the peak current flowing through the excitation inductance discharges the junction capacitance of a switching tube in a switching network to be opened to 0 in dead time, zero voltage opening of the LLC circuit is realized, and on the other hand, the automatic current sharing of the first resonant network and the second resonant network in a parallel state can be realized by adding the independent excitation inductance.
Drawings
The invention will be further described with reference to the accompanying drawings and examples, in which:
FIG. 1 is a schematic block diagram of a bidirectional DCDC circuit with automatic current sharing according to the present invention;
FIG. 2 is a schematic circuit diagram of a preferred embodiment of the automatic current sharing bi-directional DCDC circuit of the present invention;
FIG. 3 is an equivalent circuit diagram of the automatic current sharing bidirectional DCDC circuit shown in FIG. 2 when operating in the forward direction;
FIG. 4 is a schematic diagram of the current during forward operation of the auto-equalizing bi-directional DCDC circuit shown in FIG. 2;
FIG. 5 is an equivalent circuit diagram of the automatic current sharing bidirectional DCDC circuit shown in FIG. 2 when operating in reverse;
fig. 6 is a schematic diagram of the current flow of the automatic current sharing bidirectional DCDC circuit shown in fig. 2 when operating in reverse.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
The invention relates to a bidirectional DCDC circuit capable of automatically equalizing current, which comprises: the transformer module is provided with an independent excitation inductor, a first resonant network and a first switching network which are arranged on a first side of the transformer module, and a second resonant network, a third switching network and a series-parallel switching network which are arranged on a second side of the transformer module; the first end and the second end of the first switch network are connected with the first end and the second end of the first direct current network, the third end and the fourth end of the first switch network are connected with the first end and the second end of the transformer module through the first resonance network, the independent excitation inductance is connected between the first end and the second end of the transformer module so that the equivalent excitation inductance of the transformer module is connected with the independent excitation inductance in parallel, the third end and the fourth end of the transformer module are connected with the third end and the fourth end of the third switch network through the second resonance network, the first end of the third switch network is connected with the first end of the second direct current network and the first end of the series-parallel switch network, the second end of the third switch network is connected with the second end of the series-parallel switch network, the fifth end and the sixth end of the transformer module are connected with the third end and the fourth end of the fourth switch network through the third resonance network, and the first end of the fourth switch network is connected with the third end of the series-parallel switch network and the fourth end of the series-parallel switch network; when the working direction is from the first direct current network to the second direct current network or from the second direct current network to the first direct current network, the resonance currents of the second resonance network and the third resonance network are equal.
According to the invention, the independent excitation inductance is connected in parallel to one side of the transformer module, on one hand, the independent excitation inductance has the same effect as the equivalent excitation inductance of the traditional nonideal transformer, so that the switching frequency variation range is wider, the regulation and control capability is stronger and more accurate, when the LLC circuit works, the peak current flowing through the excitation inductance discharges the junction capacitance of a switching tube in a switching network to be opened to 0 in dead time, zero voltage opening of the LLC circuit is realized, and on the other hand, the automatic current sharing of the first resonant network and the second resonant network in a parallel state can be realized by adding the independent excitation inductance.
Fig. 1 is a schematic block diagram of an automatic current sharing bidirectional DCDC circuit of the present invention. As shown in fig. 1, the bidirectional DCDC circuit for automatic current sharing includes: a transformer module 100, an independent excitation inductance 600, a first resonant network 210 and a first switching network 310 disposed at a first side of the transformer module 100, and a second resonant network 220, a third resonant network 230, a third switching network 330 and a series-parallel switching network 400 disposed at a second side of the transformer module 100.
The first and second ends of the first switching network 310 are connected to the first and second ends of the first dc network 510, the third and fourth ends are connected to the first and second ends of the transformer module 100 through the first resonant network 210, the independent excitation inductance 600 is connected between the first and second ends of the transformer module 100 such that the equivalent excitation inductance of the transformer module 100 is connected in parallel with the independent excitation inductance 600, the third and fourth ends of the transformer module 100 are connected to the third and fourth ends of the third switching network 330 through the second resonant network 220, the first end of the third switching network 330 is connected to the first end of the second dc network 520 and the first end of the series-parallel switching network 400, the second end is connected to the first end of the series-parallel switching network 400, the fifth and sixth ends of the transformer module 100 are connected to the third and fourth ends of the fourth switching network through the third resonant network 230, and the fourth end of the fourth switching network is connected to the fourth end of the series-parallel switching network 400. When the working direction is from the first dc network 510 to the second dc network 520 or from the second dc network 520 to the first dc network 510, the resonant currents of the second resonant network 220 and the third resonant network 230 are equal.
In a preferred embodiment of the invention, the transformer module preferably comprises two transformer units connected in series on one side, each transformer unit may comprise at least one transformer. For example, the transformer module may include a first transformer and a second transformer, where the first transformer and the second transformer are ideal high-frequency isolation transformers, the magnetic core is made of high-permeability material (commonly used ferrite), the exciting inductance is relatively infinite, and the turns and the turn ratio are the same. Therefore, the inductance value of the parallel connection of the equivalent excitation inductance of the first transformer and the second transformer and the independent excitation inductance is close to the inductance value of the independent excitation inductance in a wireless manner.
In a preferred embodiment of the present invention, the first resonant network 210, the second resonant network 220 and the third resonant network 230 may be LC resonant networks, and these LC resonant networks and the independent exciting inductor 600 are connected in series to form an LLC circuit, and the independent exciting inductor has the same effect as the equivalent exciting inductor of the conventional non-ideal transformer, so that the switching frequency variation range is wider, the regulation capability is stronger and more accurate, and when the LLC circuit works, the peak current flowing through the exciting inductor discharges the junction capacitance of the switching tube in the switching network to be turned on to 0 in the dead time, so as to realize zero voltage turn-on of the LLC circuit.
In a preferred embodiment of the present invention, the first switching network 310, the second switching network 320 and the third switching network 330 each comprise a switching tube network of four switching tubes. The switching transistors constituting the first switching network 310 may include metal-oxide semiconductor field effect transistors, insulated gate bipolar transistors, power transistors, insulated gate field effect transistors, gate turn-off thyristors or thyristors, and the like. The switching transistors constituting the second switching network 320 and the third switching network 330 may also include metal-oxide semiconductor field effect transistors, insulated gate bipolar transistors, power transistors, insulated gate field effect transistors, gate turn-off thyristors, or the like.
In a preferred embodiment of the present invention, the series-parallel switching network 400 may include any suitable switching device, such as a single pole single throw switch, a single pole double throw switch, a relay switch, etc., to implement the parallel or series connection of the second resonant network 220 and the third resonant network 230.
In a preferred embodiment of the present invention, the first dc network 510 and the second dc network 520 may be a battery module, a single-phase active power factor correction circuit, or a three-phase active power factor correction circuit.
As shown in fig. 1, the bidirectional DCDC circuit with automatic current sharing according to the present invention is in a forward operation mode when the operation direction is from the first dc network 510 to the second dc network 520, i.e. the first dc network 510 is used as an input terminal and the second dc network 520 is used as an output terminal; the reverse operation mode is performed when the operation direction is from the second dc network 520 to the first dc network 510, i.e. when the first dc network 510 is used as an output and the second dc network 520 is used as an input. When operating in the reverse mode, the switching frequencies of the switching tubes of the second switching network 320 must be in phase, and the switching frequencies of the switching tubes of the second switching network 330 must also be in phase.
When the series-parallel switching network 400 controls the second resonant network 220 and the third resonant network 230 to be connected in series, the current of the series circuit is necessarily equalized. And at this time, the second resonant network 220 and the third resonant network 230 adopt the same LC resonant network, so that when the second resonant network 220 and the third resonant network 230 are connected in series, the second resonant network 220 and the third resonant network 230 can realize relative voltage equalizing under the condition of relatively balanced loop impedance.
When the series-parallel switching network 400 controls the second resonant network 220 and the third resonant network 230 to be connected in parallel, the automatic current sharing of the second resonant network 220 and the third resonant network 230 can be realized by adopting the bidirectional DCDC circuit for automatic current sharing of the present invention even if the loop impedance of the two resonant cavities is inconsistent due to poor consistency of device parameters, different PCB loops, control circuit errors, etc.
When the working direction is from the first dc network 510 to the second dc network 520, the resonant currents of the second resonant network 220 and the third resonant network 230 are automatically equalized to a multiple of the first side current of the transformer module. This is because the relationship of the current on both sides of the transformer module depends on the turns ratio of the transformer module. The resonant currents of the second resonant network 220 and the third resonant network 230 on the second side of the transformer module are automatically equalized to a multiple of the current on the first side of the transformer module, the specific multiple depending on the turns ratio of the transformer module.
When the working direction is from the second dc network 520 to the first dc network 510, the resonant currents of the second resonant network 220 and the third resonant network 230 are automatically equalized to the sum of the second side current of the transformer module and the equivalent resonant current of the independent exciting inductance 600 at the second side of the transformer module. This is because the independent excitation inductance 600 will be equivalent to the second side of the transformer module. And the relationship of the currents on both sides of the transformer module depends on the turns ratio of the transformer module. The resonant currents of the second resonant network 220 and the third resonant network 230 on the second side of the transformer module are automatically equalized to the sum of the second side current of the transformer module and the equivalent resonant current of the independent excitation inductance 600 on the second side of the transformer module.
Therefore, in the invention, the independent excitation inductance is connected in parallel at one side of the transformer module, on one hand, the independent excitation inductance has the same effect as the equivalent excitation inductance of the traditional nonideal transformer, so that the change range of the switching frequency is wider, the regulation and control capability is stronger and more accurate, when the LLC circuit works, the peak current flowing through the excitation inductance discharges the junction capacitance of a switching tube in the switching network to be opened to 0 in dead time, zero voltage opening of the LLC circuit is realized, and on the other hand, the automatic current sharing of the first resonant network and the second resonant network in the parallel state can be realized by adding the independent excitation inductance.
Fig. 2 is a schematic circuit diagram of a preferred embodiment of the automatic current sharing bidirectional DCDC circuit of the present invention, as can be seen in conjunction with fig. 1-2, comprising: a transformer module 100, an independent excitation inductance 600, a first resonant network 210 and a first switching network 310 disposed at a first side of the transformer module 100, and a second resonant network 220, a third resonant network 230, a third switching network 330 and a series-parallel switching network 400 disposed at a second side of the transformer module 100. The first and second ends of the first switching network 310 are connected to the first and second ends of the first dc network 510, the third and fourth ends are connected to the first and second ends of the transformer module 100 through the first resonant network 210, the independent excitation inductance 600 is connected between the first and second ends of the transformer module 100 such that the equivalent excitation inductance of the transformer module 100 is connected in parallel with the independent excitation inductance 600, the third and fourth ends of the transformer module 100 are connected to the third and fourth ends of the third switching network 330 through the second resonant network 220, the first end of the third switching network 330 is connected to the first end of the second dc network 520 and the first end of the series-parallel switching network 400, the second end is connected to the first end of the series-parallel switching network 400, the fifth and sixth ends of the transformer module 100 are connected to the third and fourth ends of the fourth switching network through the third resonant network 230, and the fourth end of the fourth switching network is connected to the fourth end of the series-parallel switching network 400. When the working direction is from the first dc network 510 to the second dc network 520 or from the second dc network 520 to the first dc network 510, the resonant currents of the second resonant network 220 and the third resonant network 230 are equal.
In the preferred embodiment shown in fig. 2, the bidirectional DCDC circuit for automatic current sharing further includes a first dc filter network, a second dc filter network, and a third dc filter network, wherein the first dc filter network is connected between the first dc network 510 and the first switching network 310, the second dc filter network is connected between the second dc network 520 and the second switching network 320, and the third dc filter network is connected between the second dc network 520 and the third switching network 330.
In the preferred embodiment shown in fig. 2, the transformer module 100 includes a transformer T1 and a transformer T2. The transformer T1 and the transformer T2 are identical ideal transformers, and the turns ratio of the transformer T1 to the transformer T2 is 1: n, where N is a positive integer greater than 1. Specifically, the equivalent inductance of the transformer T1 and the transformer equivalent excitation inductance of the transformer T2 connected in parallel with the independent excitation inductance 600 approaches the inductance of the independent excitation inductance 600 infinitely. The transformer T1 and the transformer T2 are the same type of transformers with the same number of turns and the same turn ratio, the magnetic core is made of high-permeability materials (common ferrite), and the excitation inductance is relatively infinite. Technically, it appears that the transformers T1, T2 are not air-gapped, including but not limited to.
The first end of the first side of the transformer T1 is connected to the first end of the transformer module 100, the second end of the first side of the transformer T2 is connected to the first end of the first side of the transformer T2, and the second end of the first side of the transformer T2 is connected to the second end of the transformer module 100. The independent exciting inductance 600 is connected between the first side first end of the transformer T1 and the first side second end of the transformer T2 so as to be connected in parallel with the series exciting inductances of the transformer T1 and the transformer T2. The first end and the second end of the second side of the transformer T1 are the third end and the fourth end of the transformer module 100, respectively, and the first end and the second end of the second side of the transformer T2 are the fifth end and the sixth end of the transformer module 100, respectively.
The first resonant network 210 includes a resonant inductance Lr1 and a resonant capacitance Cr1. The second resonant network 220 includes a resonant inductance Lr2 and a resonant capacitance Cr2. The third resonant network 230 includes a resonant inductance Lr3 and a resonant capacitance Cr3. The first switching network 310 includes switching tubes Q1-Q4, the second switching network 320 includes switching tubes Q5-Q8, and the third switching network 330 includes switching tubes Q9-Q12. The first direct current filter network, the second direct current filter network and the third direct current filter network respectively comprise filter capacitors C1-C3. The series-parallel switching network 400 includes a switch K1, a switch K2, and a switch K3.
In the preferred embodiment shown in fig. 2, the switching transistors Q1-Q12 comprise metal-oxide semiconductor field effect transistors, insulated gate bipolar transistors, power transistors, insulated gate field effect transistors, gate turn-off thyristors or thyristors, etc. The filter capacitors C2 and C3 are capacitors of the same model, and relative voltage equalizing in a series mode is achieved. Preferably, the filter capacitors C1-C3 may be electrolytic capacitors or polypropylene capacitors.
As shown in fig. 2, the first end of the resonant inductor Lr1 is connected to the third end of the first switching network 310 (i.e., the second end of the switching tube Q1 and the first end of the switching tube Q2), the second end is connected to the first side first end of the transformer T1 and the first end of the independent excitation inductor 600, the first end of the resonant capacitor Cr1 is connected to the fourth end of the first switching network 310 (i.e., the second end of the switching tube Q3 and the first end of the switching tube Q4), and the second end is connected to the first side second end of the transformer T2. The first ends of the switching tube Q1 and the switching tube Q3 are the first ends of the first switching network 310, and are respectively connected to the first end of the filter capacitor C1 and the positive electrode of the first dc network 510. The second ends of the switching tube Q2 and the switching tube Q4 are the second ends of the first switching network 310, and are respectively connected to the second end of the filter capacitor C1 and the negative electrode of the first dc network 510. The first end of the resonant inductor Lr2 is connected to the first end of the second side of the transformer T1, the second end is connected to the third end of the second switching network 320 (i.e., the second end of the switching tube Q7 and the first end of the switching tube Q8), the first end of the resonant capacitor Cr2 is connected to the second end of the second side of the transformer T1, and the second end is connected to the fourth end of the second switching network 320 (i.e., the second end of the switching tube Q5 and the first end of the switching tube Q6). The first ends of the switching tube Q5 and the switching tube Q7 are the first ends of the second switching network 320, which are respectively connected to the first end of the filter capacitor C2, the positive electrode of the second dc network 520, and the first end of the series-parallel switching network 400 (i.e., the fixed contact of the switch K2). The second ends of the switching tube Q6 and the switching tube Q8 are the second ends of the second switching network 320, which are respectively connected to the second end of the filter capacitor C2 and the second end of the series-parallel switching network 400 (i.e. the fixed contacts of the switch K1 and the switch K3). The first end of the resonant inductor Lr3 is connected to the first end of the second side of the transformer T2, the second end is connected to the third end of the third switching network 330 (i.e., the second end of the switching tube Q11 and the first end of the switching tube Q12), and the first end of the resonant capacitor Cr3 is connected to the second end of the second side of the transformer T2, and the second end is connected to the fourth end of the third switching network 330 (i.e., the second end of the switching tube Q9 and the first end of the switching tube Q10). The first ends of the switching tube Q9 and the switching tube Q11 are the first ends of the third switching network 320, which are respectively connected to the first end of the filter capacitor C3 and the third ends of the series-parallel switching network 400 (i.e., the moving contacts of the switch K1 and the switch K2). The second ends of the switching tube Q10 and the switching tube Q12 are the second ends of the third switching network 330, which are respectively connected to the second end of the filter capacitor C3 and the fourth end of the series-parallel switching network 400 (i.e. the moving contact of the switch K3). The switch K1 is opened, and when the switch K2 and the switch K3 are closed, the second resonant network 220 and the third resonant network 230 are connected in parallel; the second resonant network 220 and the third resonant network 230 are connected in series when the switch K1 is closed and the switch K2 and the switch K3 are open.
The turns ratio of the transformer T1 to the transformer T2 is 1: n, where N is a positive integer greater than 1. When the working direction is from the first dc network 510 to the second dc network 520, the resonant currents of the second resonant network 220 and the third resonant network 230 are automatically equalized to N times the first side current of the transformer T1. When the working direction is from the second dc network 520 to the first dc network 510, the resonant currents of the second resonant network 220 and the third resonant network 230 are automatically equalized to the sum of the second side current of the transformer T1 and the equivalent resonant current of the independent exciting inductance 600 at the second side of the transformer T1.
In the present invention, in the parallel mode, even if there is a difference in loop impedance between the second resonant network 220 and the third resonant network 230, the resonant current magnitudes of the second resonant network 220 and the third resonant network 230 may be automatically the same.
To better illustrate the principles of the present invention, the automatic current sharing bi-directional DCDC circuit shown in fig. 3-6 will be described below. Wherein, fig. 3 is an equivalent circuit diagram of the automatic current sharing bidirectional DCDC circuit shown in fig. 2 when working in the forward direction; FIG. 4 is a schematic diagram of the current during forward operation of the auto-equalizing bi-directional DCDC circuit shown in FIG. 2; FIG. 5 is an equivalent circuit diagram of the automatic current sharing bidirectional DCDC circuit shown in FIG. 2 when operating in reverse; fig. 6 is a schematic diagram of the current flow of the automatic current sharing bidirectional DCDC circuit shown in fig. 2 when operating in reverse.
When the operation direction is from the first dc network 510 to the second dc network 520, the operation is in the forward mode, and when the operation direction is from the second dc network 520 to the first dc network 510, the operation is in the reverse mode. In the reverse mode, the switching frequencies of the switching transistors Q5, Q8, Q9, Q12 must be in phase, and the switching frequencies of Q6, Q7, Q10, Q11 must be in phase.
In the automatic current sharing bidirectional DCDC circuit of the present invention, when in the forward output low voltage state, i.e. the operation direction is from the first dc network 510 to the second dc network 520, as shown in fig. 3-4. Switch K1 is open, switch K2, switch K3 is closed. The second resonant network 220 and the third resonant network 230 are in parallel connection, when the circuit is in operation, exciting current only flows through the independent exciting inductance 600, and the equivalent exciting inductance poles of the transformers T1 and T2Large and thus equivalent to no excitation current flowing. As shown in fig. 4, the first side current I of the transformer T1 T Resonant current I of first resonant network 210 Lr1 Excitation current I of independent excitation inductance 600 Lm . Since the second resonant network 220 and the second resonant network 230 are located at the second side of the transformer T1 and the second side of the transformer T2, respectively. Since the current on both sides of the transformer is related to the turns ratio, i.e. the current on the second side must be N times the current on the first side (N is the transformer turns ratio in fig. 3). The current of the second resonant network 220 and said third resonant network must be equal to N times the first side current IT of the transformer T1. Therefore, both parallel resonant networks must share current during forward power flow.
Further, when the loop impedance difference between the second resonant network 220 and the third resonant network 230 is large due to the inconsistent resonance parameters, the current of the second resonant network 220 and the third resonant network must be equal to N times the first side current IT of the transformer T1 because IT is known that the current of both sides of the transformer is only related to the turns ratio regardless of the difference between the second resonant network 220 and the third resonant network 230 according to the above formula. Therefore, both parallel resonant networks must share current during forward power flow. Therefore, the invention can still realize automatic current sharing under the unbalanced impedance of the two parallel resonance networks, and solves a series of problems affecting performance and reliability, such as insufficient derating of devices, thermal runaway and the like caused by unbalanced current sharing.
In the automatic current sharing bidirectional DCDC circuit of the present invention, when in the reverse output low voltage state, i.e. the operation direction is from the second dc network 520 to the first dc network 510, as shown in fig. 5-6. When the working direction is from the second dc network 520 to the first dc network 510, the equivalent circuit diagram is shown in fig. 5 after converting the inductance Lm of the independent excitation inductor 600 to the second resonant network 220 and the third resonant network 230, where the magnitude of the inductance Lm of the independent excitation inductor 600 after the equivalent in the second resonant network 220 and the third resonant network 230 is 2×lm/(N2). As can be seen from the foregoing equation, regardless of the difference between the second resonant network 220 and the third resonant network 230,the current on both sides of the transformer is only related to the turns ratio, so the current of the second resonant network 220 and said third resonant network must be equal to N times the current on the first side of the transformer T1, so we can get N times the current on the second side of both transformers T1 and T2 as the current on the first side of the transformer T1, i.e. it is written as I T1 . As can be seen from fig. 6, the resonant current I of the second resonant network 220 Lr2 ＝I Lmequal +I T1 Resonant current I of third resonant network 230 Lr3 ＝I Lmequal +I T1 Wherein I Lmequal The equivalent currents of the inductance of the independent excitation inductor 600 in the second resonant network 220 and the third resonant network 230 are represented, and the ratio is necessarily equal. It can be seen that the resonant current value I of the second resonant network 220 and the third resonant network 230 at the time of reverse power flow Lr2 And I Lr3 Also necessarily equal, i.e. the values of the resonant currents I of the second resonant network 220 and of said third resonant network 230 Lr2 And I Lr3 Automatic current sharing is the second side current I of the transformer T1 T1 (I T1 ＝NI t ，I t A first side current of the transformer T1) and an equivalent resonant current I of the independent excitation inductance at a second side of the first transformer Lmequal And (3) summing. Since the inductance of the independent excitation inductor 600 is equal to the equivalent current of the second resonant network 220 and the third resonant network 230, it can also be expressed as the resonant current value I of the second resonant network 220 and the third resonant network 230 Lr2 And I Lr3 Automatic current sharing is the second side current I of the transformer T1 T1 (I T1 ＝NI t ，I t A first side current of the transformer T1) and an equivalent resonant current I of the independent excitation inductance at a second side of the second transformer Lmequal And (3) summing.
Therefore, in this embodiment, by adding the independent exciting inductor 600 and the ideal transformers T1 and T2, automatic current sharing of the second resonant network 220 and the third resonant network 230 in the parallel state is achieved, which is beneficial to balancing the device current stress, thermal stress and the like of the two-path parallel resonant network, improving performance indexes, improving reliability and the like. In the invention, the independent excitation inductance Lm is connected in parallel with two ends of ideal transformers T1, T2. The independent excitation inductance Lm has the same effect as the equivalent excitation inductance of the traditional nonideal transformer, so that the switching frequency change range is wider, and the regulation and control capability is stronger and more accurate. When the LLC circuit works, the peak current flowing through the exciting inductor discharges the junction capacitance of the switching tube to be turned on to 0 in dead time, so that zero-voltage turn-on of the LLC circuit is realized. When the switch K1 is closed and the switches K2 and K3 are opened, the capacitors C2 and C3 are the same type of capacitors, so that the relative voltage equalizing can be realized under the condition that the loop impedances of the two series networks of the second resonant network 220 and the third resonant network 230 are relatively balanced. When the second resonant network 220 and the third resonant network 230 have inconsistent loop impedance due to poor consistency of device parameters, different PCB loops, control circuit errors, etc. The circuit can realize automatic current sharing. Specifically, the current of the second resonant network 220 and the third resonant network must be equal to N times the first side current IT of the transformer T1 when the operation direction is from the first dc network 510 to the second dc network 520. When the working direction is from the second dc network 520 to the first dc network 510, the resonant currents of the second resonant network 220 and the third resonant network 230 are equal to the sum of the equivalent current of the independent exciting inductance 600 in the second resonant network 220 or the third resonant network 230 and the first side current of the transformer T1 by N times. Therefore, the automatic current-sharing bidirectional DCDC circuit realizes the bidirectional flow of the energy of the direct current power supply network in real time, can still realize automatic current sharing under the condition of different impedance of the parallel resonance network, and can realize relative voltage sharing under the serial state.
While the invention has been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (9)
1. An automatic current sharing bidirectional DCDC circuit, comprising: the transformer module is provided with an independent excitation inductor, a first resonant network and a first switching network which are arranged on a first side of the transformer module, and a second resonant network, a third switching network and a series-parallel switching network which are arranged on a second side of the transformer module;
the first end and the second end of the first switch network are connected with the first end and the second end of the first direct current network, the third end and the fourth end of the first switch network are connected with the first end and the second end of the transformer module through the first resonance network, the independent excitation inductance is connected between the first end and the second end of the transformer module so that the equivalent excitation inductance of the transformer module is connected with the independent excitation inductance in parallel, the third end and the fourth end of the transformer module are connected with the third end and the fourth end of the third switch network through the second resonance network, the first end of the third switch network is connected with the first end of the second direct current network and the first end of the series-parallel switch network, the second end of the third switch network is connected with the second end of the series-parallel switch network, the fifth end and the sixth end of the transformer module are connected with the third end and the fourth end of the fourth switch network through the third resonance network, and the first end of the fourth switch network is connected with the third end of the series-parallel switch network and the fourth end of the series-parallel switch network;
when the working direction is from the first direct current network to the second direct current network or from the second direct current network to the first direct current network, the resonance currents of the second resonance network and the third resonance network are equal.
2. The auto-equalizing bidirectional DCDC circuit of claim 1, wherein said transformer module comprises a first transformer and a second transformer, said first transformer and said second transformer being identical ideal transformers, a first side first end of said first transformer being connected to a first end of said transformer module, a first side second end being connected to a first side first end of said second transformer, a first side second end of said second transformer being connected to a second end of said transformer module; the independent excitation inductor is connected between a first side first end of the first transformer and a first side second end of the second transformer so as to be connected in parallel with the series excitation inductors of the first transformer and the second transformer; the first end and the second end of the second side of the second transformer are respectively a fifth end and a sixth end of the transformer module.
3. The automatic current sharing bidirectional DCDC circuit of claim 2, wherein said first resonant network includes a first resonant inductance and a first resonant capacitance; the first end of the first resonant capacitor is connected with the fourth end of the first switch network, and the second end of the first resonant capacitor is connected with the first side second end of the second transformer.
4. The automatic current sharing bidirectional DCDC circuit of claim 3, wherein said second resonant network includes a second resonant inductance and a second resonant capacitance; the first end of the second resonant capacitor is connected with the second end of the second side of the first transformer, and the second end of the second resonant capacitor is connected with the fourth end of the second switch network;
the third resonant network comprises a third resonant inductor and a third resonant capacitor; the first end of the third resonant capacitor is connected with the second end of the second side of the second transformer, the second end of the third resonant capacitor is connected with the third end of the third switching network, and the first end of the third resonant capacitor is connected with the second end of the second side of the second transformer, and the second end of the third resonant capacitor is connected with the fourth end of the third switching network.
5. The automatic current sharing bidirectional DCDC circuit of claim 4, wherein the turns ratio of the first transformer and the second transformer is 1: n, wherein N is a positive integer greater than 1;
when the working direction is from the first direct current network to the second direct current network, the resonance currents of the second resonance network and the third resonance network are automatically equalized to N times of the first side current of the first transformer;
when the working direction is from the second direct current network to the first direct current network, the resonance currents of the second resonance network and the third resonance network are automatically equalized to the sum of the second side current of the first transformer and the equivalent resonance current of the independent excitation inductor on the second side of the first transformer.
6. The automatic current sharing bidirectional DCDC circuit of any of claims 2-5, wherein the series-parallel switching network includes a first switch, a second switch, and a third switch, wherein a fixed contact of the first switch is connected to a second end of the series-parallel switching network, a moving contact is connected to a third end of the series-parallel switching network, a fixed contact of the second switch is connected to a first end of the series-parallel switching network, a moving contact is connected to a third end of the series-parallel switching network, a fixed contact of the third switch is connected to a second end of the series-parallel switching network, and a moving contact is connected to a fourth end of the series-parallel switching network; when the first switch is opened and the second switch and the third switch are closed, the second resonant network and the third resonant network are connected in parallel; when the first switch is closed and the second switch and the third switch are opened, the second resonant network and the third resonant network are connected in series.
7. The automatic current sharing bidirectional DCDC circuit of any of claims 2-5, wherein said first switching network, said second switching network and said third switching network each comprise a switching tube network of four switching tubes; when the working direction is from the second direct current network to the first direct current network, the switching frequencies of the switching tubes of the second switching network and the third switching network are in the same phase.
8. The automatic current sharing bidirectional DCDC circuit of any of claims 2-5, further comprising a first dc filtering network; the first direct current filter network is connected between the first direct current network and the first switching network.
9. The automatic current sharing bidirectional DCDC circuit of any of claims 2-5, further comprising a second dc filter network and a third dc filter network, said second dc filter network connected between said second dc network and said second switching network, said third dc filter network connected between said second dc network and said third switching network.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311820681.1A CN117767762A (en) | 2023-12-27 | 2023-12-27 | Automatic two-way DCDC circuit that flow equalizes |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311820681.1A CN117767762A (en) | 2023-12-27 | 2023-12-27 | Automatic two-way DCDC circuit that flow equalizes |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117767762A true CN117767762A (en) | 2024-03-26 |
Family
ID=90310414
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311820681.1A Pending CN117767762A (en) | 2023-12-27 | 2023-12-27 | Automatic two-way DCDC circuit that flow equalizes |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117767762A (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110138239A (en) * | 2019-05-20 | 2019-08-16 | 深圳市优优绿能电气有限公司 | A kind of wide scope invariable power converter circuit |
| CN110995008A (en) * | 2019-12-06 | 2020-04-10 | 深圳市优优绿能电气有限公司 | Wide-range constant-power bidirectional direct-current converter |
| CN112366950A (en) * | 2020-11-02 | 2021-02-12 | 湖南大学 | Electrodeless control series/parallel bidirectional power circuit and control method thereof |
| CN113541493A (en) * | 2021-07-15 | 2021-10-22 | 深圳市优优绿能电气有限公司 | Ultra-high-power wide-range constant-power converter |
| WO2022142278A1 (en) * | 2020-12-30 | 2022-07-07 | 深圳市优优绿能电气有限公司 | Ultra-wide-range high-power converter circuit |
| CN116995937A (en) * | 2023-09-26 | 2023-11-03 | 深圳市永联科技股份有限公司 | Series-parallel switching circuit for bidirectional power conversion |
-
2023
- 2023-12-27 CN CN202311820681.1A patent/CN117767762A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110138239A (en) * | 2019-05-20 | 2019-08-16 | 深圳市优优绿能电气有限公司 | A kind of wide scope invariable power converter circuit |
| CN110995008A (en) * | 2019-12-06 | 2020-04-10 | 深圳市优优绿能电气有限公司 | Wide-range constant-power bidirectional direct-current converter |
| CN112366950A (en) * | 2020-11-02 | 2021-02-12 | 湖南大学 | Electrodeless control series/parallel bidirectional power circuit and control method thereof |
| WO2022142278A1 (en) * | 2020-12-30 | 2022-07-07 | 深圳市优优绿能电气有限公司 | Ultra-wide-range high-power converter circuit |
| CN113541493A (en) * | 2021-07-15 | 2021-10-22 | 深圳市优优绿能电气有限公司 | Ultra-high-power wide-range constant-power converter |
| CN116995937A (en) * | 2023-09-26 | 2023-11-03 | 深圳市永联科技股份有限公司 | Series-parallel switching circuit for bidirectional power conversion |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104753152A (en) | Constant current-constant voltage composite topological sensing type charging system | |
| CN109245542A (en) | A kind of symmetrical power converter circuit topological structure and its control method | |
| CN111490683A (en) | Trajectory control method for double-transformer series resonance double-active bridge DC-DC converter topology | |
| CN103081319A (en) | Common mode noise reduction appartus and method | |
| CN111464040B (en) | DCDC framework applicable to different input power grids and control method thereof | |
| Haldi et al. | A 3.5 kW wireless charger for electric vehicles with ultra high efficiency | |
| CN111082665A (en) | Bidirectional LLC direct-current transformer submodule based on centralized multiphase transformer | |
| CN112202344B (en) | Bidirectional direct-current converter with wide voltage range and adaptive switching function | |
| CN110266194B (en) | Bidirectional DC-DC converter with symmetrical resonant cavities | |
| CN111682787A (en) | Single-stage three-phase AC/DC converter based on isolation converter module and method | |
| CN112928919B (en) | Isolated high-frequency resonant DC-DC converter with wide output voltage range and method | |
| CN112290802B (en) | Ultra-wide gain range adjusting method of L-LLC resonant converter | |
| CN206117480U (en) | High -low pressure switching circuit of LLC transform output | |
| CN111786566A (en) | Control circuit for wide voltage range output of charging pile | |
| CN210780552U (en) | Bidirectional DC-DC converter with symmetrical resonant cavity | |
| CN113726173B (en) | Multiport direct current power electronic transformer | |
| CN100571006C (en) | Superconducting energy storage bidirectional three-level soft switch DC/DC converter and control method thereof | |
| CN108306514A (en) | A kind of DC-DC converter of fuel cell | |
| CN111262463B (en) | Inversion topological structure of micro-inversion system | |
| CN116345912A (en) | Three-level hybrid module type direct-current transformer | |
| CN112054685A (en) | Electric energy router and control method thereof | |
| CN117767762A (en) | Automatic two-way DCDC circuit that flow equalizes | |
| CN106208084A (en) | A kind of dynamic electric voltage recovery device and intelligent control method thereof | |
| CN105262336A (en) | Two-phase staggered magnetic integration boost converter without right half plane zero-point | |
| CN209402248U (en) | A kind of integrated difference E class rectifier of magnetic |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |