CN112087012A - High-power charging system - Google Patents
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- CN112087012A CN112087012A CN201910513707.5A CN201910513707A CN112087012A CN 112087012 A CN112087012 A CN 112087012A CN 201910513707 A CN201910513707 A CN 201910513707A CN 112087012 A CN112087012 A CN 112087012A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
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Abstract
The invention provides a high-power charging system, comprising: the input end of the multi-winding power transformer is connected with an alternating current power supply, and the output end of the multi-winding power transformer is composed of a plurality of secondary coils of the power transformer; each winding converter is respectively connected with a group of secondary coils of the power transformer and consists of a non-isolated rectifier module and a non-isolated DC/DC conversion module, the input end of the non-isolated rectifier module is connected with the group of secondary coils of the power transformer, the output end of the non-isolated rectifier module is connected with the input end of the non-isolated DC/DC conversion module, and the output end of the non-isolated DC/DC conversion module is connected with the battery. The system adopts the power frequency multi-winding transformer to realize the electrical isolation between vehicles, has lower system cost compared with the high-frequency DC/DC isolation of the existing charging system, and simultaneously, the converter of the system adopts a non-isolated AC/DC converter and a non-isolated DC/DC converter, and has higher charging efficiency compared with the isolated DC/DC converter of the traditional charging system.
Description
Technical Field
The invention belongs to the technical field of charging of new energy automobiles, and particularly relates to a high-power charging system.
Background
At present, the field of new energy vehicles is rapidly developed, electric vehicles are gradually popularized, the requirement for charging the electric vehicles is gradually improved, and how to rapidly and stably charge the electric vehicles is a considerable problem.
The existing charging system of the new energy automobile obtains electricity from a 10kV power grid, 10kV is reduced into 380V three-phase alternating current through a transformer for converting 10kV into 380V, the alternating current is converted into direct current through an AC/DC converter in a charging module, and further an isolation type DC/DC converter provides isolation and voltage regulation functions to charge a battery. The power of a traditional charging module is often designed to be 10kW, 15kW, 30kW and the like, and when the electric vehicle needs high-power charging, the high-power charging is realized through the parallel connection of the charging modules.
With the increase of the requirement on ultra-high power charging of 350kW, 400kW and the like in the market, the traditional charging system needs more charging modules to be connected in parallel, and as the charging modules utilize isolated DC/DC converters, the requirement on system control by more charging modules in parallel is higher, and meanwhile, the cost of the system is lack of competitiveness due to excessive modules in parallel. Therefore, a charging system capable of realizing high-power charging and having low cost and high efficiency is needed.
Disclosure of Invention
In order to solve the problems, the invention provides a high-power charging system, which adopts a power frequency multi-winding transformer to realize electrical isolation between vehicles, can adopt a non-isolated DC/DC converter in a winding converter, and has lower cost and higher efficiency compared with the high-frequency DC/DC isolation of the existing charging system.
In an embodiment of the present invention, a high power charging system is provided, which includes: a multi-winding power transformer and a plurality of winding transformers, wherein,
the input end of the multi-winding power transformer is connected with an alternating current power supply, and the output end of the multi-winding power transformer comprises a plurality of secondary coils of the power transformer;
each winding converter is respectively connected with a group of secondary coils of the power transformer, each winding converter comprises a non-isolated rectifying module and a non-isolated DC/DC conversion module, the input end of each non-isolated rectifying module is connected with one group of secondary coils of the power transformer, the output end of each non-isolated rectifying module is connected with the input end of each non-isolated DC/DC conversion module, and the output end of each non-isolated DC/DC conversion module is connected with a battery and used for charging the battery.
According to the high-power charging system, the power frequency multi-winding power transformer is adopted to realize the electrical isolation between vehicles, and the winding converter can adopt a non-isolated DC/DC converter, so that the high-power charging system is lower in high-frequency DC/DC isolation cost compared with the conventional charging system; in order to meet the requirement of ultra-high power charging, when a circuit is designed, a plurality of winding converters are required to be arranged on the secondary side of the transformer, and because the cost of each winding converter of the system is lower, the charging system can save a large amount of cost compared with the existing charging system; meanwhile, the converter of the system adopts a non-isolated AC/DC converter and a non-isolated DC/DC converter, and compared with an isolated DC/DC converter of a traditional charging system, the charging efficiency is higher.
Drawings
Fig. 1 is a schematic structural diagram of a high-power charging system according to an embodiment of the present invention.
Fig. 2 is a schematic diagram of a winding transformer structure according to an embodiment of the present invention.
Fig. 3 is a schematic diagram of a charging system of the prior art.
Fig. 4 is a schematic structural diagram of a high-power charging system according to a first embodiment of the present invention.
Fig. 5 is a schematic structural diagram of a high-power charging system according to a second embodiment of the present invention.
Fig. 6 is a schematic diagram of a winding transformer circuit according to a third embodiment of the present invention.
Fig. 7 is a schematic diagram of an expanded circuit structure of a winding transformer according to a third embodiment of the present invention.
The reference numbers illustrate:
101-multi-winding power transformer; 102-a winding transformer; 103-an alternating current power supply; 104-power transformer secondary winding; 105-a non-isolated rectifier module; 106-a non-isolated DC/DC conversion module; 107-battery; 108-a charging module; 109-vienna circuit; a 110-Buck circuit; 111-multiple-path staggered cascade type Buck circuit; 201-step-down transformer; 202-isolated charging module; d1, D2, D3, D4, D5, D6, D7, D8, D9, D10, D11, D12, D13, D14, D15, D16, D17-diodes; c1, C2, C3, C4, C5, C6-capacitance; s1, S2, S3, S4, S5, S6, S7, S8, S9 and S10-switch tube; l1, L2, L3-winding; l4, L5, L6, L7-inductors.
Detailed Description
In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Fig. 1 is a schematic structural diagram of a high-power charging system according to an embodiment of the present invention. As shown in fig. 1, the system includes: a multi-winding power transformer 101 and a plurality of winding transformers 102, wherein,
the input end of the multi-winding power transformer 101 is connected with an alternating current power supply 103, and the output end of the multi-winding power transformer is composed of a plurality of power transformer secondary coils 104;
each winding transformer 102 is connected to a respective set of power transformer secondary windings 104.
Further referring to fig. 2, a schematic diagram of the winding transformer is shown. As shown in fig. 2, the winding converter 102 is composed of a non-isolated rectifying module 105 and a non-isolated DC/DC converting module 106, an input end of the non-isolated rectifying module 105 is connected to a set of secondary windings 104 of the power transformer, an output end of the non-isolated rectifying module 105 is connected to an input end of the non-isolated DC/DC converting module 106, and an output end of the non-isolated DC/DC converting module 106 is connected to a battery 107.
In one embodiment, the ac power supply 103 connected to the input end of the multi-winding power transformer 101 is 10kV ac, and the ac power output from the output end is 630V.
The working process of the high-power charging system is as follows:
taking electricity from a 10kV medium-voltage power grid, converting the electricity into low-voltage three-phase alternating current through a multi-winding power transformer 101, and reducing the voltage into 630V three-phase alternating current for example;
the low-voltage three-phase alternating current is converted into direct-current voltage required by the battery of the electric vehicle through the non-isolated AC/DC converter and the non-isolated DC/DC converter, and the battery of the electric vehicle is charged.
The secondary side of the multi-winding power transformer 101 is designed in a multi-winding configuration to achieve electrical isolation between the windings. Here, after being electrically isolated, a non-isolated converter may be used as a whole in the winding converter 102.
Each secondary side is provided with a winding converter 102, and the winding converter 102 is composed of a non-isolated rectifying module 105 and a non-isolated DC/DC conversion module 106.
In an embodiment, the non-isolated rectifying module 105 may employ a non-isolated AC/DC converter, and the non-isolated DC/DC converting module 106 may employ a non-isolated DC/DC converter. The non-isolated AC/DC converter mainly realizes input current harmonic control, power factor control, and output voltage control, and the non-isolated DC/DC converter mainly realizes control of direct current voltage and current output to the battery 107.
In an embodiment, referring to fig. 3, a schematic diagram of a conventional charging system is shown. The existing charging system gets electricity from a 10kV power grid, and the electricity is converted into 380V alternating current through a step-down transformer 201 converting 10kV into 380V; the charging module is an isolated charging module 202, which converts AC/DC into direct current and then realizes isolation and voltage regulation through isolated DC/DC conversion.
According to the modularized design, each isolated charging module 202 comprises an AC/DC converter and an isolated DC/DC converter, and the power of each module is designed to be 15kW, 20kW, 30kW and the like. When high-power charging is needed, a plurality of modules can work in parallel. If ultra-high power charging requirements of 350kW, 400kW and the like are required, the charging system in FIG. 3 is utilized, the number of modules which need to be connected in parallel is very large, meanwhile, higher requirements are also put forward on the control of the modules which are connected in parallel, and each module needs an isolated DC/DC converter, so that the overall cost of the system is higher.
As can be seen from comparing fig. 1 and fig. 3, the high-power charging system proposed in the present application utilizes a multi-winding power transformer 101 to implement an electrical isolation function, whereas the existing charging system utilizes an isolation type DC/DC module isolation.
Although the efficiency of the step-down transformer is basically almost the same, in the high-power charging system of the present application, the converter of each winding converter 102 adopts a non-isolated topology, and compared with the isolated topology of fig. 3, the efficiency of the high-power charging system of the present application is higher than that of the existing system.
At the same capacity, the multi-winding power transformer 101 in fig. 1 does not increase cost much more than the step-down transformer 201 in fig. 3; compared with the isolated charging module 202 in fig. 3, the non-isolated DC/DC converter in the winding converter 102 of the present application has a non-isolated topology structure, and the non-isolated design of the present application has a lower cost and higher efficiency, and in summary, the overall cost of the system of the present application is lower than that of the system of fig. 3.
In one embodiment, the number of winding transformers 102 is the same as the number of secondary windings 104 of the power transformer.
The first embodiment is as follows:
fig. 4 is a schematic structural diagram of a high-power charging system according to a first embodiment of the present invention.
In order to meet the requirements of different power level designs, the present embodiment is further improved for the high-power charging system shown in fig. 1, and as shown in fig. 4, the present embodiment can be expanded to a multiple-winding power transformer 101 parallel topology. Although this design increases system cost, it also achieves different power charging requirements. According to the actual charging requirement, the design of one transformer, two transformers or more transformers can be adopted, and the application does not strictly limit the design.
Through the design of the secondary side multi-winding of the step-down transformer, electrical isolation among the windings is provided, each winding only charges one trolley at the same time, the requirement of isolation charging between the trolleys is met, and the vehicles are prevented from triggering grounding protection. Wherein,
the non-isolated AC/DC converter is used for controlling harmonic current (THD) and power factor, meets the requirements of a power grid on the THD and the power factor, and improves the utilization rate of equipment.
The non-isolated DC/DC converter is used for regulating output voltage and current so as to meet the requirements of the electric vehicle on voltage and current during charging.
Example two:
fig. 5 is a schematic structural diagram of a high-power charging system according to a second embodiment of the present invention.
As for the winding converter 102 on the secondary side of the multi-winding power transformer 101, a modular design may be adopted, specifically, as shown in fig. 5, the winding converter 102 includes a plurality of charging modules 108, the plurality of charging modules 108 are connected in series or in parallel, wherein each charging module 108 is composed of a non-isolated rectifier module and a non-isolated DC/DC conversion module, and such a design may reduce the cost of the system and facilitate maintenance.
When charging, the required number of charging modules 108 can be started according to the required power to realize stable charging of the battery and prevent over-high or over-low power; meanwhile, a certain number of charging modules 108 can rest under the condition of meeting the charging requirement, so that the loss of the system is reduced, and the use cost is saved.
Example three:
the high power charging system shown in fig. 1, 2, 4 and 5, wherein the winding transformer 102 may be selected from a non-isolated three-phase AC/DC circuit plus a non-isolated DC/DC circuit. The non-isolated three-phase AC/DC circuit may be a Vienna (Vienna) circuit, and the non-isolated DC/DC circuit may be a Buck circuit.
Fig. 6 is a schematic diagram of a circuit structure of a winding transformer according to an embodiment. The circuit is composed of a vienna circuit 109 and a Buck circuit 110. When the modular design shown in fig. 5 is used, the charging module 108 can operate using the circuit shown in fig. 6, and a plurality of charging modules 108 can be connected in series or in parallel.
As shown in fig. 6, the vienna circuit 109 is mainly composed of three bridge arms; wherein,
the upper bridge arm of the first bridge arm is provided with two diodes D1 and D2 which are connected in the same direction, and the connection point between the two diodes is connected with the collector electrode of a switch tube S1;
the lower bridge arm of the first bridge arm is provided with two diodes D3 and D4 which are connected in the same direction, and the connection point between the two diodes is connected with the emitter stage of a switch tube S2;
the connection directions of the diodes D1, D2, D3 and D4 are the same, the cathode of the diode D1 is connected to the positive line of the battery 107, and the anode of the diode D4 is connected to the negative line of the battery 107;
the connection point between the two bridge arms is connected with a winding L1, and the winding L1 is connected with one phase of alternating current;
the connection point between the switch tube S1 and the switch tube S2 is connected with the connection point between the capacitor C1 and the capacitor C2, and the other ends of the capacitor C1 and the capacitor C2 are respectively connected with the two ends of the bridge arm.
The other two bridge arms are composed of diodes D5, D6, D7, D8, D9, D10, D11 and D12, switching tubes S3, S4, S5 and S6, and the connection relationship of the devices is the same as that of the first bridge arm; and the connection points between the upper bridge and the lower bridge of the two bridge arms are respectively connected with one phase of alternating current through windings L2 and L3.
Referring to fig. 6, the Buck circuit 110 is connected to the wiener circuit 109, and includes a capacitor C3, a capacitor C5, a switching tube S7, a diode D13, and an inductor L4; wherein,
the capacitor C3, the diode D13 and the capacitor C5 are connected in parallel with the battery 107; in the positive line of the battery 107, the collector of the switching tube S7 is connected to one end of the capacitor C3, the emitter is connected to the cathode of the diode D13, and the inductor L4 is connected to the cathode of the diode D13 and one end of the capacitor C5; one end of the capacitor C5 is connected to the anode of the diode D17, and the cathode of the diode D17 is connected to the positive electrode of the battery 107.
The Buck circuit 110 can be extended to a multiple interleaved Buck circuit, for example, as shown in fig. 7, the Buck circuit can be extended to a multiple interleaved cascade type Buck circuit 111 to utilize a three-level characteristic. Compared with the Buck circuit 110 shown in fig. 6, the multiple interleaved cascade Buck circuit 111 includes switching devices S8, S9, and S10, inductors S5, S6, and S7, diodes D14, D15, and D16, and capacitors C4 and C6.
In one embodiment, the midpoint of the wiener circuit 109 may be selectively connected or disconnected to the midpoint of the input of the multiple interleaved cascaded Buck circuit 111.
In the above embodiments, the switching tube may be a MOS, IGBT, SCR or other type of switching tube, which is not strictly limited in this application, and all switching tubes that can achieve the above functions are within the protection scope of this application.
The terms "first," "second," "third," and the like in the description and claims of this application and in the above-described drawings are used for distinguishing between different objects and not for describing a particular order.
According to the high-power charging system, the power frequency multi-winding transformer is adopted to realize electrical isolation between vehicles, and the winding converter can adopt a non-isolated DC/DC converter, so that the high-power charging system is lower in high-frequency DC/DC isolation cost compared with the existing charging system; in order to meet the requirement of ultra-high power charging, when a circuit is designed, a plurality of winding converters are required to be arranged on the secondary side of the transformer, and because the cost of each winding converter of the system is lower, the charging system can save a large amount of cost compared with the existing charging system; meanwhile, the converter of the system adopts a non-isolated AC/DC converter and a non-isolated DC/DC converter, and compared with an isolated DC/DC converter of a traditional charging system, the charging efficiency is higher.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention, and it should be understood that the above-mentioned embodiments are only examples of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. A high power charging system, the system comprising: a multi-winding power transformer and a plurality of winding transformers, wherein,
the input end of the multi-winding power transformer is connected with an alternating current power supply, and the output end of the multi-winding power transformer comprises a plurality of secondary coils of the power transformer;
each winding converter is respectively connected with a group of secondary coils of the power transformer, each winding converter comprises a non-isolated rectifying module and a non-isolated DC/DC conversion module, the input end of each non-isolated rectifying module is connected with one group of secondary coils of the power transformer, the output end of each non-isolated rectifying module is connected with the input end of each non-isolated DC/DC conversion module, and the output end of each non-isolated DC/DC conversion module is connected with a battery and used for charging the battery.
2. The high power charging system of claim 1, comprising a plurality of multi-winding power transformers; wherein,
the multiple multi-winding power transformers are connected in parallel, the input end of the multiple multi-winding power transformers is connected to the alternating current power supply, and the output end of the multiple multi-winding power transformers is provided with multiple secondary coils of the power transformers respectively.
3. The high power charging system of claim 1, wherein the number of winding transformers is the same as the number of secondary windings of the power transformer.
4. The high-power charging system according to claim 1, wherein the winding converter comprises a plurality of charging modules, and the plurality of charging modules are connected in series or in parallel, wherein each charging module comprises a non-isolated rectifying module and a non-isolated DC/DC converting module.
5. The high-power charging system according to claim 1, wherein the input end of the multi-winding power transformer is connected with an AC power supply of 10kV AC, and the output end of the multi-winding power transformer is connected with an AC power supply of 630V.
6. The high-power charging system according to claim 1 or 4, wherein the non-isolated rectifying module is formed by a three-phase Vienna circuit or a three-phase high-frequency PWM rectifying circuit.
7. The high-power charging system according to claim 1 or 4, wherein the non-isolated DC/DC conversion module is formed by a Buck conversion circuit.
8. The high power charging system of claim 6, wherein the three-phase Vienna circuit comprises three legs; wherein,
the upper bridge arm of each bridge arm is provided with two diodes which are connected in the same direction, and the connection point between the two diodes is connected with the collector electrode of the first switching tube;
the lower bridge arm of each bridge arm is provided with two diodes which are connected in the same direction, and the connection point between the two diodes is connected with the emitter stage of the second switching tube;
a connecting point between the two bridge arms is connected with a winding, and the winding is connected with one phase of alternating current;
and the other end of the first capacitor and the other end of the second capacitor are respectively connected with the two ends of each bridge arm.
9. The high power charging system of claim 7, wherein the Buck converter circuit is composed of a third capacitor, a fourth capacitor, a first diode, a third switch tube and a first inductor; wherein,
the third capacitor, the first diode and the fourth capacitor are connected with the battery in parallel, on the circuit of the positive electrode of the battery, the collector electrode of the third switching tube is connected with one end of the third capacitor, the emitter electrode of the third switching tube is connected with the cathode of the first diode, and the first inductor is connected with the cathode of the first diode and one end of the fourth capacitor.
10. The high-power charging system according to claim 8 or 9, wherein the switching tube is a MOS switching tube, an IGBT switching tube or an SCR switching tube.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201910513707.5A CN112087012A (en) | 2019-06-14 | 2019-06-14 | High-power charging system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910513707.5A CN112087012A (en) | 2019-06-14 | 2019-06-14 | High-power charging system |
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Application publication date: 20201215 |