CN107379995B - Electric automobile quick charging system and method - Google Patents

Electric automobile quick charging system and method Download PDF

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Publication number
CN107379995B
CN107379995B CN201710649348.7A CN201710649348A CN107379995B CN 107379995 B CN107379995 B CN 107379995B CN 201710649348 A CN201710649348 A CN 201710649348A CN 107379995 B CN107379995 B CN 107379995B
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voltage
control module
charging
pulse
synchronous inverter
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CN107379995A (en
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刘其辉
张怡冰
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North China Electric Power University
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North China Electric Power University
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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
    • B60L53/00—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
    • B60L53/10—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles characterised by the energy transfer between the charging station and the vehicle
    • B60L53/11—DC charging controlled by the charging station, e.g. mode 4
    • 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
    • B60L53/00—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
    • B60L53/20—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles characterised by converters located in the vehicle
    • 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
    • H02J7/02—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from ac mains by converters
    • H02J7/04—Regulation of charging current or voltage
    • H02J7/06—Regulation of charging current or voltage using discharge tubes or semiconductor devices
    • 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
    • B60L2210/00—Converter types
    • B60L2210/10—DC to DC converters
    • B60L2210/14—Boost converters
    • 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
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/40—Drive Train control parameters
    • B60L2240/54—Drive Train control parameters related to batteries
    • B60L2240/547—Voltage
    • 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
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/00711—Regulation of charging or discharging current or voltage with introduction of pulses during the charging process
    • 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
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries
    • 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
    • Y02T10/7072—Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
    • 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
    • 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
    • Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02T90/10—Technologies relating to charging of electric vehicles
    • Y02T90/14—Plug-in electric vehicles

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)

Abstract

The invention provides a quick charging system and a quick charging method for an electric automobile, which comprise the following steps: the device comprises a stability control module, a synchronous inverter, a pulse control module and a direct current converter; the synchronous inverter is connected with a power grid and used for rectifying three-phase alternating-current voltage of the power grid into first voltage; the direct current converter is connected with the synchronous inverter and used for converting the first voltage into a second voltage; the pulse control module is connected with the direct current converter and used for controlling the direct current converter to charge a power battery of the electric automobile in a pulse charging mode, wherein the power battery is provided with charging current through second voltage; the stabilization control module is connected with the synchronous inverter and used for controlling the first voltage output by the synchronous inverter to be kept unchanged in the charging process of the power battery. According to the invention, the synchronous inverter is controlled through the stable control module, so that the problem of instantaneous power fluctuation in the pulse charging process is solved, and the adverse effect on the power quality of a power grid is greatly reduced.

Description

Electric automobile quick charging system and method
Technical Field
The invention relates to the technical field of electric automobile charging, in particular to a quick electric automobile charging system and method.
Background
The existing charging modes of the electric automobile are mainly divided into two types, one type is a conventional charging mode, and the conventional charging mode comprises constant-current charging, constant-voltage charging and staged charging; the other type is a quick charging mode, and the quick charging mode comprises a pulse charging mode, an intermittent charging mode, a variable current charging mode and the like. Along with the continuous development of electric automobile, the trip demand that can more satisfy people for conventional charging mode is compared to the quick charge technique, makes things convenient for people's use.
In practical applications, the pulse charging method in the fast charging is most widely used. The charging system can effectively shorten the charging time of the electric automobile, but in a charging period, large instantaneous power fluctuation can be generated, although the duration is short, the influence of the charging system on a power grid cannot be ignored, and if a traditional quick charging system is adopted, the current of the power grid can be changed rapidly, and the adverse effect on the quality of electric energy can be generated.
Disclosure of Invention
In view of the above, the present invention provides a system and a method for rapidly charging an electric vehicle, which control a synchronous inverter through a stable control module, so as to stabilize the instantaneous power fluctuation problem during pulse charging and greatly reduce the adverse effect on the power quality of a power grid.
In a first aspect, an embodiment of the present invention provides a fast charging system for an electric vehicle, including: the device comprises a stability control module, a synchronous inverter, a pulse control module and a direct current converter;
the synchronous inverter is connected with a power grid and used for rectifying three-phase alternating-current voltage of the power grid into first voltage and outputting the first voltage to the direct-current converter;
the direct current converter is connected with the synchronous inverter and is used for converting the first voltage into a second voltage, wherein the second voltage is smaller than the first voltage;
the pulse control module is connected with the direct current converter and is used for controlling the direct current converter to charge a power battery of the electric automobile in a pulse charging mode, wherein the power battery is provided with charging current through the second voltage;
the stability control module is connected with the synchronous inverter and used for measuring the actual voltage output by the synchronous inverter in the charging process of the power battery, calculating a driving signal of the synchronous inverter according to the difference value of the actual voltage and the first voltage, and controlling the synchronous inverter to output the first voltage through the driving signal.
With reference to the first aspect, an embodiment of the present invention provides a first possible implementation manner of the first aspect, where the pulse control module is further configured to set a charging current reference value;
when the current reference value is larger than 0, the pulse control module controls the direct current converter to perform positive pulse charging on the power battery;
when the current reference value is smaller than 0, the pulse control module controls the direct current converter to carry out negative pulse charging on the power battery;
when the current reference value is equal to 0, the pulse control module controls the direct current converter to stop charging the power battery.
With reference to the first possible implementation manner of the first aspect, an embodiment of the present invention provides a second possible implementation manner of the first aspect, where the pulse control module is further configured to measure an actual current of the dc converter, compare the actual current with the current reference value to obtain a pulse driving signal, and drive the dc converter by the pulse driving signal.
With reference to the first possible implementation manner of the first aspect, an embodiment of the present invention provides a third possible implementation manner of the first aspect, where the pulse control module is further configured to set a charging cycle, a positive and negative pulse charging current amplitude, and a ratio of positive and negative pulses of the power battery.
With reference to the first aspect, an embodiment of the present invention provides a fourth possible implementation manner of the first aspect, where the stabilization control module is further configured to calculate according to a difference between the actual voltage and the first voltage to obtain a virtual angle of the synchronous inverter, and obtain the driving signal by performing PWM control on the virtual angle and a virtual electromotive force of the synchronous inverter.
With reference to the first aspect, an embodiment of the present invention provides a fifth possible implementation manner of the first aspect, where the apparatus further includes a stabilizing circuit, connected to the synchronous inverter and the dc converter, respectively, and configured to output the stabilized first voltage to the dc converter.
With reference to the first aspect, an embodiment of the present invention provides a sixth possible implementation manner of the first aspect, where the stabilization control module includes an inertia control unit, and the inertia control unit is configured to provide inertia and damping for the synchronous inverter.
In a second aspect, an embodiment of the present invention further provides a method for quickly charging an electric vehicle, including:
rectifying the three-phase alternating-current voltage of the power grid into a first voltage through a synchronous inverter;
converting the first voltage into a second voltage through a direct current converter, wherein the second voltage is smaller than the first voltage;
controlling the direct current converter to charge the power battery in a pulse charging mode, wherein the power battery is provided with charging current through the second voltage;
in the charging process of the power battery, measuring the actual voltage output by the synchronous inverter, and obtaining a driving signal of the synchronous inverter by comparing the actual voltage with the first voltage;
and controlling the synchronous inverter to output the first voltage through the driving signal.
With reference to the second aspect, an embodiment of the present invention provides a first possible implementation manner of the second aspect, where the method further includes:
setting a charging current reference value;
when the current reference value is larger than 0, controlling the direct current converter to carry out positive pulse charging on the power battery;
when the current reference value is smaller than 0, controlling the direct current converter to carry out negative pulse charging on the power battery;
when the current reference value is equal to 0, the module controls the direct current converter to stop charging the power battery.
With reference to the first possible implementation manner of the second aspect, an embodiment of the present invention provides a second possible implementation manner of the second aspect, where the method further includes:
measuring the actual current of the direct current converter, and comparing the actual current with the current reference value to obtain a pulse driving signal;
and driving the direct current converter by the pulse driving signal.
The embodiment of the invention provides a system and a method for quickly charging an electric automobile, wherein the system comprises: the device comprises a stability control module, a synchronous inverter, a pulse control module and a direct current converter; the synchronous inverter is connected with a power grid and used for rectifying three-phase alternating-current voltage of the power grid into first voltage; the direct current converter is connected with the synchronous inverter and used for converting the first voltage into a second voltage; the pulse control module is connected with the direct current converter and used for controlling the direct current converter to charge a power battery of the electric automobile in a pulse charging mode, wherein the power battery is provided with charging current through second voltage; the stabilization control module is connected with the synchronous inverter and used for controlling the first voltage output by the synchronous inverter to be kept unchanged in the charging process of the power battery. The synchronous inverter is controlled through the stability control module, so that the problem of instantaneous power fluctuation in the pulse charging process is solved, and the adverse effect on the power quality of a power grid is greatly reduced.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic diagram of a rapid charging system for an electric vehicle according to an embodiment of the present invention;
fig. 2 is another schematic diagram of a rapid charging system for an electric vehicle according to an embodiment of the present invention;
fig. 3 is a circuit control diagram of a rapid charging system for an electric vehicle according to an embodiment of the present invention;
fig. 4 is a flowchart of a fast charging method for an electric vehicle according to a second embodiment of the present invention.
Icon:
10-a synchronous inverter; 20-a dc converter; 30-a stability control module; 40-a pulse control module; 50-stabilizing circuit.
Detailed Description
To make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some, but not all embodiments of the present invention. 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 invention.
At present, in practical application, a pulse charging mode in rapid charging can effectively shorten the charging time of an electric automobile, but in a charging period, large instantaneous power fluctuation can be generated, although the duration is short, the influence of the pulse charging mode on a power grid cannot be ignored, and if a traditional rapid charging system is adopted, the current of the power grid can be changed rapidly, and the adverse effect on the quality of electric energy can be generated. Based on the above, the electric vehicle rapid charging system and method provided by the embodiment of the invention control the synchronous inverter through the stable control module, so that the problem of instantaneous power fluctuation in the pulse charging process is solved, and the adverse effect on the power quality of a power grid is greatly reduced.
For the convenience of understanding the embodiment, the electric vehicle quick charging system disclosed in the embodiment of the present invention will be described in detail first.
The first embodiment is as follows:
fig. 1 is a schematic diagram of a rapid charging system for an electric vehicle according to an embodiment of the present invention.
Referring to fig. 1, the electric vehicle rapid charging system includes: a stabilization control module 30, a synchronous inverter 10, a pulse control module 40, and a dc converter 20;
a synchronous inverter 10 connected to a grid, for rectifying a three-phase ac voltage of the grid into a first voltage and outputting the first voltage to the dc converter 20;
a dc converter 20 connected to the synchronous inverter 10 for converting the first voltage into a second voltage, wherein the second voltage is smaller than the first voltage;
specifically, the synchronous inverter 10 includes a rectifier circuit for ac-dc conversion, and the dc converter 20 includes a current reversible type step-up/step-down converter circuit for dc-dc conversion. The synchronous inverter 10 is connected with a power grid and can rectify three-phase alternating-current voltage of the power grid into 600V direct-current voltage; the DC converter 20 converts the 600V DC voltage into 50V DC voltage, and is directly connected with a power battery of the electric automobile.
The pulse control module 40 is connected with the dc converter 20 and is used for controlling the dc converter 20 to charge the power battery of the electric vehicle in a pulse charging mode, wherein the charging current is provided for the power battery through the second voltage;
the bidirectional flow of energy is realized through a discharging process by a pulse charging mode, namely a positive and negative pulse quick charging mode, which comprises the charging process, a short-time discharging process and a charging stopping process; the short-time discharging and charging stopping process can eliminate the polarization phenomenon in the battery, reduce the gassing amount, break through the limitation that the current limit value of the battery is smaller and smaller in the charging process, improve the extreme value of the charging current of the battery, be beneficial to realizing the quick charging target of the electric automobile and improve the charging efficiency.
And the stabilization control module 30 is connected with the synchronous inverter 10, and is configured to measure an actual voltage output by the synchronous inverter 10 during a charging process of the power battery, calculate a driving signal of the synchronous inverter 10 according to a difference between the actual voltage and the first voltage, and control the synchronous inverter 10 to output the first voltage through the driving signal.
As shown in fig. 3, VT1～VT6Form a synchronous inverter 10, VT7And VT8The direct current converter 20 is formed, a stability control module 30 of the synchronous inverter 10 comprises four parts, namely a calculation module, an active control module, an inertia control module and a reactive control module, and the active control module is used for controlling to ensure the voltage on the direct current side to be stable; the inertia control module mainly aims at providing inertia and damping for a system, inhibiting power fluctuation and improving the stability of grid-connected exchange power; the purpose of the reactive power control module is to ensure the constant voltage of the grid-connected point of the rectification system.
The calculation module can calculate reactive power, electromagnetic power and virtual electromotive force. The specific calculation formulas are shown as (1), (2), (3) and (4):
Figure GDA0002732957180000071
Figure GDA0002732957180000072
Figure GDA0002732957180000073
Figure GDA0002732957180000074
wherein M isfifIs a virtual rotor flux linkage igFor grid current, the angle θ may be integrated from a virtual angular frequency ω, which may be obtained by an inertial control module. Q is the actual reactive power and e is the virtual EMF.
The purpose of the active control module is to ensure constant dc-side voltage, which module can obtain an active power command P for the synchronous inverter 10m。VrefIs a reference DC voltage value of the rectifier system, V is an actual measured value of the DC voltage of the rectifier system, KpIs a scaling factor. When the DC side voltage amplitude has an error with its reference value, i.e. Δ V ═ VrefWhen V, calculate Pm＝ΔV*KpTo obtain the actual active power instruction Pm。
The inertia control module simulates the rotor regulation process of the synchronous generator, and the mathematical model of the inertia control module is as the following formula (5):
Figure GDA0002732957180000081
Figure GDA0002732957180000082
wherein the electromagnetic torque TeAnd mechanical torque TmThis can be obtained from the following equation (6):
Pe＝Kpsinδ
Tm＝Pm/ω0
Te＝Pe/ω0 (6)
in the above model, ω0The power grid angular frequency is shown, omega is the virtual angular frequency of the synchronous inverter 10, and delta is the operation power angle; Δ ω is the angular frequency difference; j is a virtual inertia time constant and represents the magnitude of inertia contained in the system; t iseIs an electromagnetic torque, i.e. a torque corresponding to the power exchanged by the synchronous inverter 10 with the load; t ismIs a mechanical torque, i.e. a torque corresponding to the power exchanged by the synchronous inverter 10 with the grid; torque may be divided by power by ω0Thus obtaining the product. KdAs damping coefficient, KpIn order to synchronize the static power limits that the inverter 10 can exchange with the grid.
The inertia control module gives an actual active power instruction P in the control processmAnd electromagnetic power PeMaking a difference, dividing by the grid angular frequency omega0And obtaining a torque difference value. According to the formula
Figure GDA0002732957180000083
And (3) subtracting the torque difference value from the damping torque, dividing the difference by an inertia time constant J, and obtaining the virtual angular frequency omega through an integral link. The virtual angular frequency ω can be integrated to obtain the angle θ, as shown in fig. 3.
In the reactive control module, Q is shown in FIG. 3refFor a given reactive reference value, Q is the actual reactive power, VmIs a reference output voltage, emFor the output voltage of the virtual synchronous machine system, KqFor the reactive-voltage regulation coefficient, the parameter K is related to the response speed of the voltage control loop, the smaller K, the faster the response speed. Reference output voltage VmAnd output voltage e of virtual synchronous machine systemmMake a differenceIs multiplied by KqAnd the excitation regulation process of the grid-connected control system is adopted. After excitation regulation and integration links, a virtual rotor flux linkage M is obtainedfif. And the virtual electromotive force e can be obtained through the calculation module.
Further, the pulse control module 40 is further configured to set a charging current reference value;
when the current reference value is greater than 0, the pulse control module 40 controls the direct current converter 20 to perform positive pulse charging on the power battery;
when the current reference value is less than 0, the pulse control module 40 controls the direct current converter 20 to perform negative pulse charging on the power battery;
when the current reference value is equal to 0, the pulse control module 40 controls the dc converter 20 to stop charging the power battery.
Further, the pulse control module 40 is further configured to measure an actual current of the dc converter 20, compare the actual current with a current reference value to obtain a pulse driving signal, and drive the dc converter 20 through the pulse driving signal.
Further, the pulse control module 40 is further configured to set a charging period of the power battery, a positive and negative pulse charging current amplitude, and a ratio of positive and negative pulses.
Specifically, the control process of the dc converter 20 is as follows:
step one, as shown in fig. 1, setting a charging period of the electric vehicle, a positive and negative pulse charging current amplitude and a ratio of positive and negative pulses according to an actual power battery requirement.
And step two, after the setting is finished, the electric automobile starts to be charged. When the charging is started, the pulse control module 40 gives a charging current reference value I*. When I is*>When 0, charging the power battery for positive pulse; when I is*When the charging time is equal to 0, the charging is stopped, and the power battery is not charged or discharged; when I is*<And when 0, the negative pulse is charged, and the power battery is discharged. As shown in FIG. 3, the current I is measured from the DC converter 20, and the current reference value I*Making difference, inputting the difference value into PI controller, making ratio with triangular carrier wave, and inputtingThe pulse driving signal of 0 or 1 is obtained in the comparator and then transmitted to VT7And VT8In this case, the operation of the dc converter 20 is controlled.
Further, the stabilization control module 30 is further configured to calculate according to a difference between the actual voltage and the first voltage to obtain a virtual angle of the synchronous inverter 10, and obtain a driving signal by performing PWM control on the virtual angle and the virtual electromotive force of the synchronous inverter 10.
Specifically, the control process of the synchronous inverter 10 is as follows:
step one, VrefV is a reference DC voltage value (i.e. the first voltage) of the synchronous inverter 10, V is an actual measured value of the DC voltage of the synchronous inverter 10, KpIs a scaling factor. When the DC side voltage amplitude has an error with its reference value, i.e. Δ V ═ VrefWhen V is lower than Pm＝ΔV*KpCalculating to obtain the actual active power Pm。
Step two, the actual active power PmAnd the electromagnetic power P obtained by the calculation moduleeMaking a difference, dividing by the grid angular frequency omega0And obtaining a torque difference value. According to the formula
Figure GDA0002732957180000101
And (3) subtracting the torque difference value from the damping torque, dividing the difference by an inertia time constant J, and obtaining the virtual angular frequency omega through an integral link. The angle theta can be obtained through an integration link.
Step three, referring to the output voltage VmAnd output voltage e of virtual synchronous machine systemmTaking the difference, multiplying by KqAnd performing excitation adjustment process of the virtual synchronous machine system. To be given a reactive reference QrefMaking difference with the actual reactive power Q obtained by the calculation module, and obtaining the virtual rotor flux linkage M after excitation regulation and integration linksfif. And then the virtual electromotive force e can be obtained through a calculation module.
Step four, the angle theta and the virtual electromotive force e are transmitted to a PWM control link to obtain VT1～VT6Of the synchronous inverter 10And (5) operating.
Further, as shown in fig. 2, the power supply further includes a stabilizing circuit 50, which is connected to the synchronous inverter 10 and the dc converter 20, respectively, and is configured to output a first stable voltage to the dc converter 20. Such as the capacitor C in fig. 31Its function is to stabilize the output voltage of the synchronous inverter 10.
Further, the stability control module 30 includes an inertial control unit for providing inertia and damping to the synchronous inverter 10.
In the embodiment of the invention, during the positive and negative pulse charging and discharging process of the synchronous inverter 10, the current on the side of the power grid is not changed and basically remains unchanged in the negative pulse stage. Although the power fluctuates instantaneously in the negative pulse charging process of the battery, the inertia damping link of the synchronous inverter 10 has an inhibiting effect on the fluctuation of the power and effectively eliminates the fluctuation of the instantaneous power, so that the impact of the negative pulse charging process on a power grid can be effectively inhibited, and the adverse effect of the quick charging process of the electric automobile on the power quality of the power grid is reduced.
Example two:
fig. 4 is a flowchart of a fast charging method for an electric vehicle according to a second embodiment of the present invention.
Referring to fig. 4, the method for rapidly charging an electric vehicle includes:
step S101, rectifying the three-phase alternating-current voltage of the power grid into a first voltage through a synchronous inverter;
step S102, converting the first voltage into a second voltage through a direct current converter, wherein the second voltage is smaller than the first voltage;
step S103, controlling the direct current converter to charge the power battery in a pulse charging mode, wherein the power battery is provided with charging current through second voltage;
step S104, in the charging process of the power battery, measuring the actual voltage output by the synchronous inverter, and obtaining a driving signal of the synchronous inverter by comparing the actual voltage with the first voltage;
step S105, controlling the synchronous inverter to output the first voltage by the driving signal.
Further, still include:
setting a charging current reference value;
when the current reference value is greater than 0, controlling the direct current converter to carry out positive pulse charging on the power battery;
when the current reference value is less than 0, controlling the direct current converter to carry out negative pulse charging on the power battery;
when the current reference value is equal to 0, the module controls the direct current converter to stop charging the power battery.
Further, still include:
measuring the actual current of the direct current converter, and comparing the actual current with a current reference value to obtain a pulse driving signal;
the dc converter is driven by a pulsed drive signal.
The electric vehicle quick charging method provided by the embodiment of the invention has the same technical characteristics as the electric vehicle quick charging system provided by the embodiment, so that the same technical problems can be solved, and the same technical effects can be achieved.
The embodiment of the invention provides a system and a method for quickly charging an electric automobile, wherein the system comprises: the device comprises a stability control module, a synchronous inverter, a pulse control module and a direct current converter; the synchronous inverter is connected with a power grid and used for rectifying three-phase alternating-current voltage of the power grid into first voltage; the direct current converter is connected with the synchronous inverter and used for converting the first voltage into a second voltage; the pulse control module is connected with the direct current converter and used for controlling the direct current converter to charge a power battery of the electric automobile in a pulse charging mode, wherein the power battery is provided with charging current through second voltage; the stabilization control module is connected with the synchronous inverter and used for controlling the first voltage output by the synchronous inverter to be kept unchanged in the charging process of the power battery. The synchronous inverter is controlled through the stability control module, so that the problem of instantaneous power fluctuation in the pulse charging process is solved, and the adverse effect on the power quality of a power grid is greatly reduced.
In addition, in the description of the embodiments of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units is only one logical division, and there may be other divisions when actually implemented, and for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection of devices or units through some communication interfaces, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.
The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a non-volatile computer-readable storage medium executable by a processor. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
Finally, it should be noted that: the above-mentioned embodiments are only specific embodiments of the present invention, which are used for illustrating the technical solutions of the present invention and not for limiting the same, and the protection scope of the present invention is not limited thereto, although the present invention is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: any person skilled in the art can modify or easily conceive the technical solutions described in the foregoing embodiments or equivalent substitutes for some technical features within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the embodiments of the present invention, and they should be construed as being included therein. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (6)

1. The utility model provides an electric automobile quick charge system which characterized in that includes: the system comprises a stability control module, a synchronous inverter, a pulse control module and a direct current converter, wherein the stability control module comprises an inertia control unit; the inertia control unit is used for providing inertia and damping for the synchronous inverter;
the synchronous inverter is connected with a power grid and used for rectifying three-phase alternating-current voltage of the power grid into first voltage and outputting the first voltage to the direct-current converter;
the direct current converter is connected with the synchronous inverter and is used for converting the first voltage into a second voltage, wherein the second voltage is smaller than the first voltage;
the pulse control module is connected with the direct current converter and is used for controlling the direct current converter to charge a power battery of the electric automobile in a pulse charging mode, wherein the pulse charging mode is a positive and negative pulse quick charging mode and comprises charging, short-time discharging and charging stopping processes; wherein the power battery is provided with a charging current through the second voltage;
the stability control module is connected with the synchronous inverter and used for measuring the actual voltage output by the synchronous inverter in the charging process of the power battery, calculating a driving signal of the synchronous inverter according to the difference value of the actual voltage and the first voltage, and controlling the synchronous inverter to output the first voltage through the driving signal;
the stability control module also comprises an active control module and a reactive control module, and the active control module is used for controlling to ensure the voltage on the direct current side to be stable; the reactive control module aims to ensure the constant voltage of a grid-connected point of the rectification system;
the mathematical model applied in the process of simulating the rotor regulation of the synchronous generator is as follows:
Figure FDA0002732957170000011
Figure FDA0002732957170000012
the electromagnetic torque Te and the mechanical torque Tm are obtained from the following equations:
Pe＝Kpsinδ
Tm＝Pm/ω0
Te＝Pe/ω0
in the above model, ω0The angular frequency of the power grid is, omega is the virtual angular frequency of the synchronous inverter (10), and delta omega is the angular frequency difference; delta is an operation power angle; j is a virtual inertia time constant and represents the magnitude of inertia contained in the system; te is electromagnetic torque; tm is mechanical torque; kd is the damping coefficient, KpIs the static power limit that the synchronous inverter can exchange with the grid; pm is the actual active power command, and Pe is the electromagnetic power.
2. The electric vehicle quick charging system of claim 1, wherein the pulse control module is further configured to set a charging current reference value;
when the current reference value is larger than 0, the pulse control module controls the direct current converter to perform positive pulse charging on the power battery;
when the current reference value is smaller than 0, the pulse control module controls the direct current converter to carry out negative pulse charging on the power battery;
when the current reference value is equal to 0, the pulse control module controls the direct current converter to stop charging the power battery.
3. The rapid electric vehicle charging system of claim 2, wherein the pulse control module is further configured to measure an actual current of the dc converter, compare the actual current with the current reference value to obtain a pulse driving signal, and drive the dc converter with the pulse driving signal.
4. The electric vehicle quick charging system of claim 2, wherein the pulse control module is further configured to set a charging cycle, a positive and negative pulse charging current amplitude, and a positive and negative pulse ratio of the power battery.
5. The electric vehicle quick charging system according to claim 1, wherein the stabilization control module is further configured to calculate according to a difference between the actual voltage and the first voltage to obtain a virtual angle of the synchronous inverter, and obtain the driving signal by performing PWM control on the virtual angle and a virtual electromotive force of the synchronous inverter.
6. The rapid charging system for electric vehicles according to claim 1, further comprising a stabilizing circuit connected to the synchronous inverter and the dc converter, respectively, for outputting the stabilized first voltage to the dc converter.
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