CN112994150A - Overcurrent and overvoltage fault protection system and method for V2G charging pile - Google Patents
Overcurrent and overvoltage fault protection system and method for V2G charging pile Download PDFInfo
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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
- H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
- H02J7/00302—Overcharge protection
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60L55/00—Arrangements for supplying energy stored within a vehicle to a power network, i.e. vehicle-to-grid [V2G] arrangements
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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
- H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
- H02J7/00308—Overvoltage protection
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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
- H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
- H02J7/0031—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits using battery or load disconnect circuits
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/72—Electric energy management in electromobility
Abstract
The invention discloses an overcurrent and overvoltage fault protection system and method based on a V2G charging pile. The overcurrent and overvoltage fault protection system is integrated into the V2G charging pile through an overcurrent and overvoltage protection module. The two types of protection adopt modular design, and each phase of the microgrid side protection module consists of a power electronic device IGBT and a current-limiting voltage-limiting high-resistance part, and the three phases are total. The automobile side protection module consists of an anti-series power electronic device IGBT and a current-limiting voltage-limiting high-resistance part, and the two parts are shared. Each phase or each pole of the micro-grid side and the automobile side is formed by connecting two power electronic devices IGBT in series in a reverse direction and then connecting the power electronic devices IGBT in parallel with a current-limiting voltage-limiting high resistance to form an overcurrent and overvoltage fault protection system module. Protection of a microgrid side: the overcurrent and overvoltage protection module is connected in series in the main circuit system at the side of the microgrid to form a protection circuit; automobile side protection: the over-current and over-voltage protection module is connected in series on a direct-current positive and negative main circuit which is interconnected with the direct current of the automobile to form a protection circuit.
Description
Technical Field
The invention belongs to the technical field of Vehicle-to-Grid (V2G) automobile charging piles, and particularly relates to an overcurrent and overvoltage fault protection system and method for a V2G charging pile, which are suitable for various charging piles to achieve the function of quickly protecting a micro-Grid side and an automobile energy storage unit against overvoltage and overcurrent.
Background
Along with electric automobile charging technology matures gradually in recent years, energy density of an electric automobile energy storage unit is larger and larger, sales volume and market share of electric automobiles are promoted rapidly, and meanwhile, electric automobile charging pile manufacturing enterprises are driven to develop vigorously. According to the data organized by Ministry of public Security and the institutes of the warp and university industries, the quantity of new energy vehicles in China is 417 thousands of vehicles and the fuel vehicles are multiplied by the speed by 6 months in 2020. The latest research finds that most of the electric automobiles are in a parking idle state in one day, more than 90% of the electric automobiles only run for 1 hour each day, and enough electric automobiles are connected to a power grid after the electric automobiles are popularized and used for regulation and control of an intelligent power grid.
The electric automobile is charged by absorbing energy from the power grid in the electricity consumption valley period, the electric energy of the electric automobile energy storage unit is fed back to the power grid in the electricity consumption peak period, the peak clipping and valley filling effects are achieved on the power grid, and therefore the V2G vehicle-grid interconnection technology plays a vital role. Compared with the charging of the traditional electric automobile, the V2G charging pile technology has great advantages and wide application prospects.
V2G fills electric pile and conventional electric pile and all utilizes mechanical circuit breaker to accomplish when realizing fault protection such as overcurrent, excessive pressure, when little electric wire netting, car energy storage unit and fill electric pile inside when breaking down, detecting element detects the trouble and uploads to the controller, the controller issues protection action instruction and gives mechanical circuit breaker, the inside action mode of circuit breaker belongs to magnetic release mechanical type protection, mechanical protection has certain error and action time delay, conventional circuit breaker protection action time delay is at tens of milliseconds at the utmost.
A fault may have propagated and caused an irreversible accident at a protection delay of the order of milliseconds or even tens of milliseconds. For example, the electric automobile spontaneously ignites due to long-time overcurrent and overvoltage, and the micro-grid causes other loads to stop running due to tripping of a superior switch due to a subordinate fault. Along with the popularization increase of charging piles and electric vehicles, similar safety accidents can increase day by day.
Disclosure of Invention
In order to solve the defects in the prior art, the invention aims to provide an overcurrent and overvoltage fault protection system and method for a V2G charging pile, wherein the overcurrent and overvoltage fault protection system for the V2G charging pile is utilized to reduce the fault current to A level within microsecond level of faults such as overcurrent and overvoltage and clamp overvoltage, so that the fault range is narrowed rapidly. The defects that the fault is enlarged due to long time delay of the protection action of the mechanical circuit breaker and the main contact is adhered when the fault heavy current and high voltage are cut off can be completely overcome. The protection action delay is shortened, the fault range is reduced, and the breaker cuts off fault small current in safe voltage when encountering faults, so that the reliability and the safety of the micro-grid, the V2G charging pile and the electric automobile are improved.
The invention adopts the following technical scheme. The invention provides a V2G charging pile overcurrent and overvoltage fault protection system in a first aspect, which is arranged in a V2G charging pile and comprises: a micro-grid side mechanical breaker and an automobile side direct current mechanical breaker, which are characterized in that,
Further comprising: the system comprises a microgrid side overcurrent and overvoltage fault protection module and an automobile side overcurrent and overvoltage fault protection module;
the microgrid side overcurrent and overvoltage protection module is arranged on a microgrid side main circuit between a microgrid to which the V2G charging pile is connected and the AC/DC bidirectional converter;
the automobile side protection module is arranged on an automobile side main loop between the DC input/output of the DC/DC bidirectional isolation type converter and the DC mechanical breaker;
the microgrid side overcurrent and overvoltage fault protection module and the automobile side overcurrent and overvoltage fault protection module are respectively controlled by independent drive plates.
Preferably, each phase of the microgrid-side overcurrent and overvoltage protection module is formed by connecting at least two IGBTs in series in an anti-parallel mode and then connecting the IGBTs in parallel with a current-limiting and voltage-limiting high resistor, and the three phases are connected in series into a main circuit on the microgrid side as an integral unit.
Preferably, the IGBT parameters of the microgrid-side protection module are expressed by the following formulas (1) and (2),
in the formula:
Ug_IGBTrepresenting the IGBT rated voltage of the microgrid-side protection module,
Upwhich is indicative of an extreme fault voltage,
UNACrepresenting the peak value of the phase voltage on the microgrid side,
UDCrepresenting the maximum direct current voltage of the charging side of the conventional automobile;
in the formula:
Ig_IGBTrepresenting the rated current of the IGBT of the microgrid-side protection module,
INACRepresents the effective value of the maximum phase current on the micro-grid side,
a denotes a first safety margin constant,
p denotes the V2G charging pile power rating,
ULrepresenting the microgrid side line voltage.
Preferably, each stage of the direct-current positive and negative poles of the automobile side protection module is formed by connecting at least two IGBTs in series in the reverse direction and then connecting the IGBTs in parallel with the current-limiting voltage-limiting high resistor, and the two poles are shared and are connected into an automobile side main loop in series as an integral unit.
Preferably, the IGBT parameters of the car side protection module are expressed by the following formulas (3) and (4),
Uc_IGBT>Up (3)
in the formula:
Uc_IGBTindicating the IGBT rated voltage of the car side protection module,
Upwhich is indicative of an extreme fault voltage,
Ic_IGBTrepresenting the rated current of the IGBT of the automobile network side protection module,
INDCrepresents the maximum effective value of the direct current on the direct current side,
beta represents a second safety margin constant,
p denotes the V2G charging pile power rating,
UDCrepresents the maximum direct current voltage of the charging side of the conventional automobile.
In another aspect of the invention, the invention provides a V2G charging pile overcurrent and overvoltage fault protection method based on the V2G charging pile overcurrent and overvoltage fault protection system, which is characterized in that,
if a fault occurs on the side of the microgrid or between the side of the microgrid and the AC/DC bidirectional converter, the IGBT of the overcurrent and overvoltage protection module on the side of the microgrid is locked and disconnected or desaturated and disconnected at a microsecond level, and the current-limiting voltage-limiting high-resistance switching system is adopted;
If a fault occurs on the automobile side or between the automobile side and the AC/DC bidirectional converter, the IGBT of the automobile side protection module is locked and disconnected or desaturated and disconnected at microsecond level, and the current-limiting voltage-limiting high-resistance input system is adopted.
Preferably, when an overcurrent and overvoltage fault occurs at the microgrid side, an IGBT drive board of the microgrid side overcurrent and overvoltage protection module receives a protection instruction and is switched off in a microsecond-level locking mode, and the current-limiting and voltage-limiting high-resistance switching system is used for limiting fault current and clamping fault voltage and then the microgrid side mechanical circuit breaker is used for protecting action and completely switching off the fault system.
Preferably, when a short-circuit fault occurs between the microgrid side and the AC/DC bidirectional converter, the IGBT drive board of the microgrid side overcurrent and overvoltage protection module enables the IGBT to be directly desaturated and turned off without any protection instruction, the current-limiting voltage-limiting high-resistance switching system is used for limiting a short-circuit current, the whole process detects that the effect of limiting the fault current from a short circuit is less than a first set time, and then the microgrid side mechanical circuit breaker is used for protecting and completely turning off the fault system.
Preferably, when an overcurrent and overvoltage fault occurs at the automobile side, the IGBT drive board of the automobile side protection module receives a protection instruction and is switched off in a microsecond-level locking mode, and the current-limiting voltage-limiting high-resistance switching system is used for limiting the fault current and clamping the fault voltage, and then the direct-current mechanical circuit breaker at the automobile side performs protection action and the fault system is switched off completely.
Preferably, when a short-circuit fault of one kind occurs between the automobile side and the DC/DC bidirectional isolation type converter, the IGBT drive board of the automobile side protection module enables the IGBT to be directly desaturated and turned off without any protection instruction, the current-limiting voltage-limiting high-resistance switching system is used for limiting short-circuit current of one kind, the whole process detects that the effect of the short-circuit of one kind to the limiting fault current is less than second set time, and then the automobile side direct-current mechanical circuit breaker is used for protecting action and the fault system to be thoroughly turned off.
Compared with the prior art, the overcurrent and overvoltage fault protection system for the V2G charging pile has the advantages that the influence caused by overcurrent and overvoltage faults can be reduced to the minimum range, and the mechanical breaker can be reliably turned off under the conditions of safe voltage and small current. When the V2G charging pile and the peripheral system have overcurrent, short circuit or overvoltage faults, the IGBT is used for locking, limiting the current and voltage at microsecond level, limiting the fault current at A level and clamping the fault voltage at the same time, so that the defects of fault expansion caused by long protection action delay of the mechanical breaker, fault heavy current cutting, main contact adhesion of the mechanical breaker at high voltage, operation overvoltage generated by cutting off the heavy current and the like can be completely overcome. The probability of reliability, the stability reduction accident of V2G charging pile, little electric wire netting, electric automobile in the interconnection process can be improved.
Drawings
Fig. 1 is a schematic diagram of a topology structure of a V2G charging pile including an overcurrent and overvoltage protection module according to the present invention;
FIG. 2 is a schematic diagram of a micro-grid side overcurrent and overvoltage protection module topology and wiring according to the present invention;
FIG. 3 is a schematic diagram of the topological structure and wiring of the automobile side overcurrent and overvoltage protection module according to the present invention; (ii) a
FIG. 4 is a schematic waveform of one type of short circuit desaturation protection of the IGBT drive board of the present invention;
10-a microgrid side protection module;
11-microgrid-side fault point;
12-point of failure between microgrid side and AC/DC converter;
20-AC/DC bidirectional converter;
a 30-DC/DC bidirectional isolation type converter;
40-a vehicle side protection module;
41-fault point between automobile side and DC/DC converter;
42-vehicle side failure point;
50-an electric vehicle;
QF 1-microgrid-side mechanical breaker;
QF 2-automotive side direct current mechanical breaker;
l1-filter reactor;
RC-resistance-capacitance absorber.
Detailed Description
The present application is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present application is not limited thereby.
As shown in fig. 1, the invention provides an overcurrent and overvoltage fault protection system for a V2G charging pile, which is arranged inside a V2G charging pile, and comprises: the system comprises a micro-grid side mechanical breaker QF1, a micro-grid side protection module 10, a filter reactor L1, a resistance-capacitance absorber RC, an AC/DC bidirectional converter 20, a DC/DC bidirectional isolation type converter 30, an automobile side protection module 40 and an automobile side direct current mechanical breaker QF 2.
The microgrid side overcurrent and overvoltage protection module is arranged on a microgrid side main circuit between a microgrid connected with the V2G charging pile and the AC/DC bidirectional converter 20; the automobile side protection module is arranged on an automobile side main loop between the direct current input and output of the DC/DC bidirectional isolation type converter 30 and the direct current mechanical breaker QF 2; the microgrid side overcurrent and overvoltage fault protection module and the automobile side overcurrent and overvoltage fault protection module are respectively controlled by independent drive plates.
As shown in fig. 2, each phase of the microgrid-side overcurrent and overvoltage protection module is formed by connecting at least two IGBTs in series in an anti-parallel manner and then connecting the IGBTs in parallel with a current-limiting and voltage-limiting high resistor, and the three phases are connected in series in a main circuit on the microgrid side as an integral unit. The microgrid-side protection module needs to be connected in series between a microgrid-side mechanical breaker QF1 and a filter reactor L1, and under normal conditions, an IGBT inside the microgrid-side protection module needs to bear normally transmitted alternating current and alternating voltage in the operation process of a V2G charging pile.
As a preferred aspect of the present invention, the skilled person can select the IGBT of the microgrid-side protection module in the following manner. The IGBT parameters of the microgrid-side protection module are expressed by the following formulas (1) and (2),
In the formula:
Ug_IGBTrepresenting the IGBT rated voltage of the microgrid-side protection module,
Upwhich is indicative of an extreme fault voltage,
UNACrepresenting the peak value of the phase voltage on the microgrid side,
UDCrepresenting the maximum direct current voltage of the charging side of the conventional automobile;
in the formula:
Ig_IGBTrepresenting the rated current of the IGBT of the microgrid-side protection module,
INACrepresents the effective value of the maximum phase current on the micro-grid side,
a denotes a first safety margin constant, which it will be understood that a person skilled in the art may configure according to safety requirements, a preferred but non-limiting embodiment being, a 1.5,
p denotes the V2G charging pile power rating,
ULrepresenting the microgrid side line voltage.
It should be noted that, when selecting the type, those skilled in the art can select the type according to the principle of selecting larger size or not selecting smaller size if there is no corresponding specification.
For an example of charging a 380V micro-grid system 750V automobile direct current input and output direct current pole in 30kW, the maximum phase current effective value at the micro-grid side is
If the first safety margin constant α is 1.5, α · INACWhen the model is selected, I is required for the rated current of the IGBT of the microgrid-side protection module, I is 1.5 × 46 ═ 69Ag_IGBTIs more than or equal to 69. The maximum AC voltage peak value borne by the IGBT in the whole charging and discharging process is
When the breakdown condition of a power electronic power device in the AC/DC conversion module is met, the peak value of the limiting voltage of an IGBT (insulated Gate Bipolar transistor) loaded in the micro-grid side power protection module is U p＝UNAC+UDC＝311+
When the model is selected, the rated voltage of the IGBT of the microgrid side protection module needs U (insulated gate bipolar translator) when 750 is 1061Vg_IGBT>1061V。
Based on the above calculation, 100A and 1700V IGBTs can be selected as IGBTs of the microgrid-side protection module, as shown in fig. 4, when a conventional IGBT meets a short-circuit condition under the coordination of driving, the IGBT can automatically detect and complete turn-off within 5 μ S within 4-5 times of rated current, and when the IGBT is loaded into the microgrid-side power protection module under the condition that a power electronic power device inside the AC/DC conversion module breaks down, the limit voltage peak value of the IGBT inside the microgrid-side power protection module is far lower than the voltage capability bearing range of the IGBTs, so that the IGBT has sufficient voltage bearing margin. The model of the current-limiting voltage-limiting high resistance can be directly selected on the market according to actual requirements, and is selective and wide.
As shown in fig. 3, each stage of the dc positive and negative poles of the car side protection module is formed by connecting at least two IGBTs in series in reverse and then in parallel with a current-limiting voltage-limiting high resistance, and the common two poles are connected in series to a car side main loop as an integral unit. The vehicle-side protection module needs to be connected in series between the DC/DC bidirectional isolated converter 30 and the direct-current mechanical switch. Under normal conditions, the IGBT inside the automobile test protection module needs to bear normally transmitted direct current and direct voltage in the operation process of the V2G charging pile.
As a preferred aspect of the present invention, the IGBT selection of the vehicle-side protection module may be performed by those skilled in the art in the following manner.
The IGBT parameters of the car side protection module are expressed by the following equations (3) and (4),
Uc_IGBT>Up (3)
in the formula:
Uc_IGBTIGBT rating for presentation of automotive side protection moduleThe voltage is applied to the surface of the substrate,
Upwhich is indicative of an extreme fault voltage,
Ic_IGBTrepresenting the rated current of the IGBT of the automobile network side protection module,
INDCrepresents the maximum effective value of the direct current on the direct current side,
beta denotes a second safety margin constant, to be understood that the person skilled in the art can configure the first safety margin constant according to safety requirements, a preferred but non-limiting embodiment being, beta is 1.5,
p denotes the V2G charging pile power rating,
UDCrepresents the maximum direct current voltage of the charging side of the conventional automobile.
It should be noted that, when selecting the type, those skilled in the art can select the type according to the principle of selecting larger size or not selecting smaller size if there is no corresponding specification.
Similarly, for example, a 380V micro-grid system 750V automobile direct current input and output direct current of a 30kW charging pile is used, and the maximum direct current effective value on the direct current side is
If the second safety margin constant β is 1.5, β · INDCWhen the model is selected, the IGBT rated current of the automobile network side protection module needs I c_IGBTNot less than 60A. The maximum direct current voltage peak value borne by the IGBT in the whole charging and discharging process is less than 750V.
Based on the above calculation, 100A and 1700V IGBTs can be selected as IGBTs of the microgrid-side protection module, as shown in fig. 4, when a conventional IGBT meets a short-circuit condition under the matching of driving, the IGBT can automatically detect and complete turn-off within 5 μ S within 4-5 times of rated current, and when a DC/DC power internal power electronic power device breaks down, the maximum voltage peak value of the IGBT loaded inside the direct-current side power protection module is 750V, which is far lower than the voltage capability bearing range of the IGBT, and has sufficient voltage bearing margin. The model of the current-limiting and voltage-limiting high resistance can be directly selected and selected in the market according to actual requirements and is wide.
The invention also discloses a V2G charging pile overcurrent and overvoltage fault protection method based on the V2G charging pile overcurrent and overvoltage fault protection system,
when the automobile obtains electric energy from a power grid, the V2G charging pile is connected into a micro-grid system, a power grid side mechanical breaker QF1 is closed, an IGBT in a micro-grid side protection module is conducted, the micro-grid conducts a filter wave reactor L1 to uncontrollably charge the AC/DC bidirectional converter 20, after the uncontrolled charge is completed, the AC/DC bidirectional converter 20 is unlocked, the direct-current voltage of a direct-current support capacitor is controlled in a target range, the DC/DC bidirectional isolation type converter 30 establishes voltage required by charging of the electric automobile 50 according to an instruction, the direct-current mechanical breaker QF2 is closed, the automobile side protection module is conducted at the same time, and the electric automobile 50 is charged.
When an automobile releases electric energy to a microgrid, the direct current mechanical breaker QF2 is closed, an IGBT in the automobile side protection module is conducted, the DC/DC bidirectional isolation type converter 30 charges a direct current support capacitor of the AC/DC bidirectional converter 20, when the voltage of the direct current support capacitor reaches a target value, an AC/DC inversion unit of the AC/DC bidirectional converter 20 is unlocked, alternating current voltage with required amplitude and frequency is output, the microgrid side protection module is conducted, the grid side mechanical breaker QF1 is closed, and electric energy is transmitted to the microgrid through L1.
As shown in fig. 2, if a fault occurs at the microgrid side or between the microgrid side and the AC/DC bidirectional converter 20, that is, the fault point is a microgrid side fault point 11 or a fault point 12 between the microgrid side and the AC/DC converter, the IGBT of the microgrid side overcurrent and overvoltage protection module is locked and disconnected or desaturated and disconnected at the microsecond level, and the current-limiting, voltage-limiting and high-resistance switching system is used; more specifically:
when overcurrent and overvoltage faults occur on the side of the microgrid, an IGBT drive board of the microgrid side overcurrent and overvoltage protection module receives a protection instruction and is switched off in a microsecond-level locking mode, and the current-limiting voltage-limiting high-resistance switching system is used for limiting fault current and clamping fault voltage, and then a microgrid side mechanical breaker QF1 protects actions and completely switches off the fault system.
When a short-circuit fault of the same type occurs between the microgrid side and the AC/DC bidirectional converter 20, the IGBT drive board of the microgrid side overcurrent and overvoltage protection module enables the IGBT to be directly desaturated and turned off without any protection instruction, the current-limiting voltage-limiting high-resistance switching system is used for limiting a short-circuit current of the same type, the effect of the short-circuit of the same type to the fault-limiting current is detected in the whole process to be less than a first set time, and then the microgrid side mechanical breaker QF1 protects the action and the fault system to be thoroughly turned off.
As shown in fig. 3, if a fault occurs on the automobile side or between the automobile side and the DC/DC bidirectional isolated converter 30, that is, the fault point is an automobile side fault point 42 or a fault point 41 between the automobile side and the DC/DC converter, the IGBT of the automobile side protection module is locked and disconnected or desaturated and disconnected at microsecond level, and the current-limiting, voltage-limiting and high-resistance system is put into operation. More specifically:
when an overcurrent and overvoltage fault occurs on the automobile side, the IGBT drive board of the automobile side protection module receives a protection instruction and is switched off in a microsecond-level locking mode, the current-limiting voltage-limiting high-resistance switching system is used for limiting fault current and clamping fault voltage, and then the automobile side direct-current mechanical circuit breaker QF2 protects actions and completely switches off the fault system.
When a short-circuit fault of one kind occurs between the automobile side and the DC/DC bidirectional isolation type converter 30, the IGBT drive board of the automobile side protection module enables the IGBT to be directly desaturated and shut down under the condition that no protection instruction exists, the current-limiting voltage-limiting high-resistance switching system is used for limiting short-circuit current of one kind, the effect of limiting the fault current from one kind of short circuit is detected in the whole process to be less than second set time, and then the automobile side direct current mechanical breaker QF2 protects the action and the fault system to be thoroughly disconnected.
The V2G charging pile mainly comprises a power electronic device, a filter inductor, a direct current supporting capacitor and an RC filter absorption loop, wherein the power electronic device in the V2G charging pile belongs to the weakest device, the power electronic device is easy to receive static electricity and magnetic field interference generated by switching on and off of an inverter to generate faults, overvoltage and overcurrent borne by the power electronic device are always in microsecond level, a conventional mechanical breaker receives a protection instruction and finally breaks in millisecond level, the power electronic device can be damaged early and cannot achieve the effect of protecting the power electronic device, the conventional mechanical breaker can only protect the filter inductor, the direct current supporting capacitor and other devices, and the charging pile cannot meet the requirements of V2G on protection rapidity, reliability and accuracy.
The overcurrent and overvoltage fault protection system for the V2G charging pile can reduce the influence caused by overcurrent and overvoltage faults to the minimum range, and ensures that the mechanical breaker is reliably turned off under the conditions of safe voltage and small current. When the V2G charging pile and the peripheral system have overcurrent, short circuit or overvoltage faults, the IGBT is used for locking, limiting the current and voltage at microsecond level, limiting the fault current at A level and clamping the fault voltage at the same time, so that the defects of fault expansion caused by long protection action delay of the mechanical breaker, fault heavy current cutting, main contact adhesion of the mechanical breaker at high voltage, operation overvoltage generated by cutting off the heavy current and the like can be completely overcome. The probability of reliability, the stability reduction accident of V2G charging pile, little electric wire netting, electric automobile in the interconnection process can be improved.
The present applicant has described and illustrated embodiments of the present invention in detail with reference to the accompanying drawings, but it should be understood by those skilled in the art that the above embodiments are merely preferred embodiments of the present invention, and the detailed description is only for the purpose of helping the reader to better understand the spirit of the present invention, and not for limiting the scope of the present invention, and on the contrary, any improvement or modification made based on the spirit of the present invention should fall within the scope of the present invention.
Claims (10)
1. The utility model provides a V2G fills electric pile overcurrent overvoltage fault protection system, sets up inside V2G fills electric pile, includes: a micro-grid side mechanical breaker (QF1) and an automobile side direct current mechanical breaker (QF2), characterized in that,
further comprising: the system comprises a microgrid side overcurrent and overvoltage fault protection module and an automobile side overcurrent and overvoltage fault protection module;
the microgrid side overcurrent and overvoltage protection module is arranged on a microgrid side main circuit between a microgrid to which the V2G charging pile is connected and the AC/DC bidirectional converter (20);
the automobile side protection module is arranged on an automobile side main loop between the direct current input and output of the DC/DC bidirectional isolation type converter (30) and the direct current mechanical breaker (QF 2);
the microgrid side overcurrent and overvoltage fault protection module and the automobile side overcurrent and overvoltage fault protection module are respectively controlled by independent drive plates.
2. The V2G charging post overcurrent overvoltage fault protection system of claim 1,
each phase of the microgrid side overcurrent and overvoltage protection module is formed by connecting at least two IGBTs in series in an anti-series mode and then connecting the IGBTs in parallel with a current-limiting voltage-limiting high resistor, and three phases are formed in total and are connected into a main circuit on the microgrid side in series as an integral unit.
3. The V2G charging post overcurrent overvoltage fault protection system of claim 2,
The IGBT parameters of the microgrid-side protection module are expressed by the following formulas (1) and (2),
in the formula:
Ug_IGBTrepresenting the IGBT rated voltage of the microgrid-side protection module,
Upwhich is indicative of an extreme fault voltage,
UNACrepresenting the peak value of the phase voltage on the microgrid side,
UDCrepresenting the maximum direct current voltage of the charging side of the conventional automobile;
in the formula:
Ig_IGBTrepresenting the rated current of the IGBT of the microgrid-side protection module,
INACrepresents the effective value of the maximum phase current on the micro-grid side,
a denotes a first safety margin constant,
p denotes the V2G charging pile power rating,
ULrepresenting the microgrid side line voltage.
4. The V2G charging post overcurrent and overvoltage fault protection system of any one of claims 1 to 3,
each stage of the direct-current positive electrode and the direct-current negative electrode of the automobile side protection module is formed by connecting two IGBTs in series in a reverse direction and then connecting the IGBTs in parallel with a current-limiting voltage-limiting high resistor, and the direct-current positive electrode and the direct-current negative electrode of the automobile side protection module share two electrodes and are connected into an automobile side main loop in series as.
5. The V2G charging post overcurrent overvoltage fault protection system of claim 4,
the IGBT parameters of the car side protection module are expressed by the following equations (3) and (4),
Uc_IGBT>Up (3)
in the formula:
Uc_IGBTindicating the IGBT rated voltage of the car side protection module,
Upwhich is indicative of an extreme fault voltage,
Ic_IGBTRepresenting the rated current of the IGBT of the automobile network side protection module,
INDCrepresents the maximum effective value of the direct current on the direct current side,
beta represents a second safety margin constant,
p denotes the V2G charging pile power rating,
UDCrepresents the maximum direct current voltage of the charging side of the conventional automobile.
6. A V2G charging pile overcurrent and overvoltage fault protection method based on the V2G charging pile overcurrent and overvoltage fault protection system of any one of claims 1 to 5,
if a fault occurs at the side of the microgrid or between the side of the microgrid and the AC/DC bidirectional converter (20), the IGBT of the overcurrent and overvoltage protection module at the side of the microgrid is locked and disconnected at a microsecond level or is disconnected after desaturation, and the current-limiting, voltage-limiting and high-resistance input system is used;
if a fault occurs on the automobile side or between the automobile side and the AC/DC bidirectional converter (20), the IGBT of the automobile side protection module is locked and disconnected or desaturated and disconnected at microsecond level, and the current-limiting voltage-limiting high-resistance input system is adopted.
7. The V2G charging post overcurrent overvoltage fault protection method of claim 6,
when overcurrent and overvoltage faults occur on the microgrid side, an IGBT drive board of the microgrid side overcurrent and overvoltage protection module receives a protection instruction and is switched off in a microsecond-level locking mode, and the current-limiting voltage-limiting high-resistance switching system is used for limiting fault current and clamping fault voltage, and then a microgrid side mechanical breaker (QF1) performs protection action and the fault system is switched off completely.
8. The V2G charging post overcurrent overvoltage fault protection method of claim 7,
when a short-circuit fault occurs between the microgrid side and the AC/DC bidirectional converter (20), the IGBT driving board of the microgrid side overcurrent and overvoltage protection module enables the IGBT to be directly desaturated and shut down under the condition that no protection instruction exists, the current-limiting voltage-limiting high-resistance switching system is used for limiting a short-circuit current, the effect of the first class of short circuit to the limitation of the fault current is detected in the whole process to be less than a first set time, and then the protection action of the microgrid side mechanical breaker (QF1) and the fault system are thoroughly disconnected.
9. The V2G charging post overcurrent overvoltage fault protection method of claim 6,
when an overcurrent and overvoltage fault occurs on the automobile side, the IGBT drive board of the automobile side protection module receives a protection instruction and is switched off in a microsecond-level locking mode, the current-limiting voltage-limiting high-resistance switching system is used for limiting fault current and clamping fault voltage, and then the automobile side direct-current mechanical breaker (QF2) performs protection action and the fault system is switched off completely.
10. The V2G charging post overcurrent overvoltage fault protection method of claim 9,
when a short-circuit fault of one kind occurs between the automobile side and the DC/DC bidirectional isolation type converter (30), the IGBT drive board of the automobile side protection module enables the IGBT to be directly desaturated and shut down under the condition that no protection instruction exists, the current-limiting voltage-limiting high-resistance switching system is used for limiting short-circuit current of one kind, the time from the detection of one kind of short circuit to the action of limiting the fault current is shorter than second set time in the whole process, and then the protection action of the automobile side direct current mechanical breaker (QF2) and the fault system are thoroughly disconnected.
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| US20160257216A1 (en) * | 2014-06-12 | 2016-09-08 | King Fahd University Of Petroleum And Minerals | Autonomous charging management system for electric vehicles |
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- 2021-02-05 CN CN202110170118.9A patent/CN112994150A/en active Pending
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|---|---|---|---|---|
| CN103731017A (en) * | 2013-12-26 | 2014-04-16 | 北京四方继保自动化股份有限公司 | Short-circuit protection system of energy-storage bidirectional converter |
| US20160257216A1 (en) * | 2014-06-12 | 2016-09-08 | King Fahd University Of Petroleum And Minerals | Autonomous charging management system for electric vehicles |
| CN104617796A (en) * | 2015-03-06 | 2015-05-13 | 南京南瑞继保电气有限公司 | Modular AC/DC converter and inverter topology |
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