CN117895555A - Electric automobile fills electric pile that possesses trouble electric wire netting and supports and emergent power supply function - Google Patents
Electric automobile fills electric pile that possesses trouble electric wire netting and supports and emergent power supply function Download PDFInfo
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Abstract
The application relates to an electric automobile charging pile with fault power grid supporting and emergency power supply functions. The processor of the electric automobile charging pile is used for realizing the following steps: in response to detecting a power grid fault, determining a current reference value of a converter of the electric vehicle charging pile based on a current vector angle; and adopting a follow-up control strategy, and carrying out fault current distribution based on the current reference value. The electric vehicle charging pile can automatically adjust the control strategy and the output current when the power grid fails, and enhance the power grid voltage supporting capability of the electric vehicle charging pile.
Description
Technical Field
The application relates to the technical field of electric power, in particular to an electric automobile charging pile with fault power grid supporting and emergency power supply functions.
Background
Currently, more and more electric automobile charging piles start to provide discharge auxiliary services for supporting reliable power supply of a power distribution network, and the adverse problem that system strength and inertia are reduced is solved. However, the distribution network is usually located at the tail end of the power system, the operation environment is complex, short-circuit fault occurrence is frequent, and if the electric vehicle charging pile does not have the power grid fault ride through capability, the charging equipment and the electric vehicle can be damaged under the condition of power grid fault or current abnormality.
Common electric automobile charging pile current generally adopts a following-net type charging control strategy, and most of the common electric automobile charging pile current does not have short-time fault ride-through capability, and can be blocked and stopped during faults.
Disclosure of Invention
Accordingly, it is necessary to provide an electric vehicle charging pile with a fault grid support and emergency power supply function, in order to solve the above-mentioned problems.
In a first aspect, the application provides an electric vehicle charging pile with fault grid support and emergency power supply functions, which comprises a processor, wherein the processor is used for realizing the following steps:
in response to detecting a power grid fault, determining a current reference value of a converter of the electric vehicle charging pile based on a current vector angle;
And adopting a follow-up control strategy, and carrying out fault current distribution based on the current reference value.
In one embodiment, the current vector angle is determined using the steps of:
Detecting line impedance of the electric automobile charging pile to obtain the ratio of line reactance and line resistance of the electric automobile charging pile;
based on the ratio, a current vector angle is determined.
In one embodiment, line impedance detection is performed on an electric vehicle charging pile to obtain a ratio of line reactance and line resistance of the electric vehicle charging pile, including:
Injecting current with preset frequency into a line to be tested;
Measuring a voltage response caused by the injected current using a voltage sensor at a voltage response location of the line; the voltage response includes impedance information of the line;
calculating the impedance of the line to be measured at a preset frequency based on the current and voltage responses; wherein, the impedance is the ratio of the phase and the amplitude of the voltage and the current;
and according to the impedance value, the ratio of the line reactance and the line resistance of the line to be tested is obtained.
In one embodiment, determining the current vector angle based on the ratio includes:
When (when) When determining that the current vector angle is/> ;
When (when) When determining that the current vector angle is/> ;
When (when) When determining that the current vector angle is/> And/> related to the specific gravity of the line inductance and the resistance of the electric automobile charging pile;
Wherein X is the line reactance, R is the line resistance, Is the ratio of the line reactance to the line resistance; /(I) Is the current vector angle.
In one embodiment, determining a current reference value of a current transformer of an electric vehicle charging pile based on a current vector angle includes:
The d-axis current reference value and the q-axis current reference value of the current transformer are determined based on the current vector angle by adopting the following expression:
Wherein,, For the current vector angle,/> D-axis current reference value output by the voltage loop; /(I) A q-axis current reference value output for the voltage loop; i max maximum allowable current amplitude preset for electric automobile charging pile converter,/> Is the d-axis current reference value of the converter,/> Is the q-axis current reference value of the current transformer.
In one embodiment, the processor is further configured to implement the steps of:
and in response to the detection of the recovery of the power grid fault or the detection of the reclosing failure of the power grid fault, adopting a grid-structured control strategy to control the current of the electric vehicle charging pile.
In a second aspect, the application further provides a control method for the charging pile of the electric automobile, which comprises the following steps:
in response to detecting a power grid fault, determining a current reference value of a converter of the electric vehicle charging pile based on a current vector angle;
And adopting a follow-up control strategy, and carrying out fault current distribution based on the current reference value.
In a third aspect, the present application further provides an electric vehicle charging pile control device, including:
The current reference value determining module is used for determining a current reference value of a converter of the electric vehicle charging pile based on a current vector angle in response to the detection of the power grid fault;
and the current distribution module is used for distributing fault current based on the current reference value by adopting a follow-up grid type control strategy.
In a fourth aspect, the present application also provides a computer readable storage medium having stored thereon a computer program which when executed by a processor performs the steps of the method described above.
In a fifth aspect, the application also provides a computer program product comprising a computer program which, when executed by a processor, implements the steps of the method described above.
According to the electric vehicle charging pile with the fault power grid supporting and emergency power supply functions, the current reference value of the converter of the electric vehicle charging pile is determined based on the current vector angle by responding to the detection of the power grid fault; by adopting the follow-up grid type control strategy, fault current distribution is carried out based on the current reference value, so that the control strategy and the output current can be automatically adjusted when the power grid fails, and the fault power grid voltage supporting capacity of the electric vehicle charging pile is enhanced.
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In order to more clearly illustrate the embodiments of the present application or the technical solutions in the related art, the drawings that are required to be used in the embodiments or the related technical descriptions will be briefly described, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.
Fig. 1 is a schematic flow chart of a method for controlling a charging pile of an electric vehicle according to an embodiment;
FIG. 2 is a flow chart illustrating determining a current vector angle in one embodiment;
FIG. 3 is a schematic flow chart of a circuit impedance detection of an electric vehicle charging pile to obtain a ratio of a circuit reactance and a circuit resistance of the electric vehicle charging pile in one embodiment;
FIG. 4 is a system operation flow chart of a method for controlling a charging pile of an electric vehicle according to another embodiment;
FIG. 5 is a control block diagram of an electric vehicle charging pile grid in one embodiment;
Fig. 6 is a fault grid support control diagram of an electric vehicle charging pile in one embodiment;
Fig. 7 is a block diagram illustrating a structure of an electric car charging pile control device according to an embodiment.
Detailed Description
The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.
In order to solve the problem that a conventional electric vehicle charging pile is locked and stopped when a power grid fails, in one embodiment, an electric vehicle charging pile with a fault power grid supporting and emergency power supply function is provided, the electric vehicle charging pile comprises a processor, as shown in fig. 1, the processor can be used for realizing the following steps:
And 102, responding to the detection of the power grid fault, and determining a current reference value of a converter of the electric vehicle charging pile based on the current vector angle.
The power grid fault can be a power grid voltage drop fault, or can be a situation that current is abnormal due to abnormal connection with a power grid, an electric vehicle charging pile is over-current, and the like. Under the condition of power grid faults or current anomalies, the charging of the electric automobile can be switched to be synchronous with the grid, and the current reference value of the converter of the charging pile of the electric automobile is determined according to the current vector angle.
Wherein the current vector angle is used to indicate the directional angle of the current vector with respect to a reference axis (e.g., d-axis or q-axis). In a three-phase alternating current system, the current vector is typically represented by a complex number, having an amplitude and a phase angle. The netlike dq axis is the coordinate system used in the power system to describe a three-phase ac motor. It is a mathematical tool for converting the electrical quantity of a three-phase ac motor into dq-axis variables in rectangular coordinates for analysis and control. In the grid dq-axis coordinate system, the d-axis (straight axis) corresponds to the magnetic field axis of the motor, and the q-axis (orthogonal axis) is perpendicular to the d-axis. The d-axis is generally aligned with the magnetic field direction of the motor, while the q-axis is perpendicular to the magnetic field. By transforming the electrical quantities (e.g. current, voltage) of the three-phase motor into the dq coordinate system, analysis and control can be more conveniently performed.
Further, a current reference value of the current transformer of the electric vehicle charging pile can be determined based on the current vector angle. Illustratively, the d-axis current reference value and the q-axis current reference value are determined in a grid dq-axis coordinate system.
And 104, performing fault current distribution based on the current reference value by adopting a follow-up network type control strategy.
Specifically, the following-grid control is a control of the load-side inverter to change the load current in accordance with a change in the grid voltage. The core idea of the follow-net control is to consider the inverter as a load and realize the control of the inverter by simulating the response of the load to the power grid. In the follow-up control, the output voltage and frequency of the inverter are determined by the power grid voltage and frequency, and the inverter only needs to adjust the output current according to the change of the power grid voltage and frequency.
Based on the current reference value obtained in the previous step and the frequency value obtained by using phase-locked loop calculation, fault current distribution can be performed on the converter.
According to the electric vehicle charging pile with the fault power grid supporting and emergency power supply functions, a current reference value of a converter of the electric vehicle charging pile is determined based on a current vector angle in response to detection of a power grid fault; and a grid following control strategy is adopted, fault current distribution is carried out based on a current reference value, and if the power grid temporarily fails in a short time, the electric vehicle charging pile can ensure that the power grid is not disconnected and can carry out maximized quantitative power output at the same time so as to support the rapid recovery of the fault power grid.
In one embodiment, as shown in FIG. 2, the following steps may be used to determine the current vector angle:
s202, line impedance detection is carried out on the electric automobile charging pile, and the ratio of the line reactance and the line resistance of the electric automobile charging pile is obtained.
Wherein Reactance (REACTANCE) refers to the ability of the circuit to store and release electromagnetic energy, generally represented by the symbol X, in ohms (Ω). The value of the reactance depends on the capacitive or inductive properties of the circuit element, the magnitude of which is related to the speed of current change in the circuit. The effect of reactance is smaller when the current changes slower, and more pronounced when the current changes faster. Resistance (Resistance) refers to the degree to which the flow of electrons in a circuit is impeded, and is generally indicated by the symbol R in ohms (Ω).
S204, determining the current vector angle based on the ratio.
Specifically, the line may appear inductive, resistive, or a combination of both for different line reactance to line resistance ratios. The inductance is used to adjust the electrical characteristics of the line by adding an inductive element to the grid line. The resistance is the electrical characteristic of the line regulated by adding a resistive element in the grid line. For different ratios, the corresponding settings of the power grid lines are different, and the corresponding current vector angles are different. For example, when the line appears inductive, the current vector angle may be And outputting reactive current to support the electric vehicle charging pile converter under the condition of grid voltage drop so as to support the grid voltage. When the circuit shows resistance, the current vector angle can be adjusted to support the electric automobile charging pile converter to output active current to support the power grid voltage under the power grid voltage drop situation.
In one embodiment, determining the current vector angle based on the ratio may include:
When (when) When determining that the current vector angle is/> ;
When (when) When determining that the current vector angle is/> ;
When (when) When determining that the current vector angle is/> And/> related to the specific gravity of the line inductance and the resistance of the electric automobile charging pile;
Wherein X is the line reactance, R is the line resistance, Is the ratio of the line reactance to the line resistance; /(I) Is the current vector angle.
Specifically, when when the power grid line appears to be inductive, the current reference vector angle/>, is set And the electric automobile charging pile converter outputs reactive current to support the power grid voltage under the power grid voltage drop situation. When/> When the power grid line appears to be constitutive, the current reference vector angle/> And the electric automobile charging pile converter outputs active current to support the power grid voltage under the power grid voltage drop situation. When/> When it is required to set/>, according to the specific gravity of line sensitivity and resistance .
In the electric vehicle charging pile with the fault power grid supporting and emergency power supplying functions, the current vector angle is determined based on the ratio of the line reactance and the line resistance of the electric vehicle charging pile, the active and reactive components of the output current of the electric vehicle charging pile in the power grid fault current limiting mode are determined according to the power grid line inductance ratio in the power grid fault, the fault power grid voltage supporting capacity of the electric vehicle charging pile is enhanced, and the better power grid fault voltage supporting capacity can be provided in a self-adaptive mode according to the power grid line condition.
In one embodiment, as shown in fig. 3, the line impedance detection is performed on the electric vehicle charging pile to obtain a ratio of a line reactance and a line resistance of the electric vehicle charging pile, which may include the following steps:
Step 302, current with preset frequency is injected into the line to be tested.
Specifically, a current source or an injection transformer may be used to inject a current of a known frequency into the line under test to generate a relevant parameter in the line under test, and to measure and calculate the relevant characteristic parameter.
Step 304, measuring voltage response caused by injected current by using a voltage sensor at a voltage response position of the line; the voltage response includes impedance information of the line.
Where the voltage responsive location may be at the other end of the line or other location of interest. At the voltage corresponding location, the voltage response caused by the injected current can be measured using a voltage sensor. The voltage response contains information about the impedance of the line. Specifically, in a circuit, the resistance and reactance may be combined to form a complex impedance, which is the impedance of the circuit to an ac power source, generally represented by the symbol Z in ohms (Ω). The complex impedance consists of resistance and reactance, the magnitude and phase angle of which depend on the circuit characteristics.
Step 306, calculating the impedance of the line to be measured at a preset frequency based on the current and voltage responses; wherein, the impedance is the ratio of the phase and the amplitude of the voltage and the current;
the impedance of the line at the injection frequency can be calculated using the relationship between the injection current and the measured voltage.
Step 308, according to the impedance value, the ratio of the line reactance and the line resistance of the line to be tested is obtained.
In general, the ratio of line reactance to line resistance of the line under test can be derived based on the impedance value using ohm's law in complex form.
In one specific example, the grid-side line resistance to reactance and its ratio can be calculated as follows:
the electric vehicle charging pile converter controller is used as a virtual current source or an external current source at a selected frequency, and a small-amplitude alternating current disturbance current i is injected into a power grid r=Ir*sin(ωr t), assuming an angular frequency of ω r frequencies around the fundamental frequency, such as 45Hz or 55Hz, are typically chosen to induce a voltage response at the converter outlet; at this time, the measured voltage v is detected by the converter controller c=Vc*sin(ωct+φc ) Measuring angular frequency omega c should be equal to omega r The initial phase is phi c The calculation can be performed by the following formula:
Line impedance measurement amplitude Z cThe method comprises the following steps:
The measured amplitudes of the line resistance Rc and the reactance Xc are respectively as follows:
Wherein i is r For injecting the instantaneous value of the alternating disturbance current, ir is the amplitude corresponding to the injected disturbance current, v c Measuring an instantaneous value of the voltage for the converter tap; vc is the amplitude corresponding to the measured voltage, zc is the measured amplitude of the line impedance.
Based on the above formula, the ratio of the line reactance and the line resistance of the line to be measured can be obtained.
In one embodiment, determining the current reference value of the current transformer of the electric vehicle charging pile based on the current vector angle may include:
The d-axis current reference value and the q-axis current reference value of the current transformer are determined based on the current vector angle by adopting the following expression:
Wherein,, For the current vector angle,/> D-axis current reference value output by the voltage loop; /(I) A q-axis current reference value output for the voltage loop; i max maximum allowable current amplitude preset for electric automobile charging pile converter,/> Is the d-axis current reference value of the converter,/> Is the q-axis current reference value of the current transformer.
In one embodiment, the processor may be further configured to implement the steps of:
and in response to the detection of the recovery of the power grid fault or the detection of the reclosing failure of the power grid fault, adopting a grid-structured control strategy to control the current of the electric vehicle charging pile.
Specifically, the electric automobile charging pile adopts a grid-structured control strategy under the condition of normal operation, and is replaced by a grid-following control strategy when the power grid fails, so that when the recovery of the power grid fails is detected, the electric automobile charging pile is replaced by the grid-structured control strategy, and the normal operation of the electric automobile charging pile is recovered.
In an actual application scene, after the fault is recovered or when the permanent fault occurs due to the power grid fault reclosing failure, the electric automobile charging pile is recovered to be in network construction control, the voltage source characteristic is kept, the emergency power supply support of the system is realized, and power is provided for the key load.
In order to further explain the scheme of the embodiment of the application, a specific example is used for describing, as shown in fig. 4, that the electric car charging pile is constructed to control operation in a network mode during normal operation, and a network construction control method is adopted to support inertia, phase jump power and the like for power grid operation so as to realize the support for stable operation of the power grid.
Detecting a circuit component of the circuit, calculating to obtain the ratio of the reactance and the resistance of the circuit, and further determining the angle of the current vector through the ratio . When the power grid fault detection operation detects the power grid fault (such as power grid voltage drop fault and overcurrent of the electric automobile charging pile), limiting the current reference value of the electric automobile charging pile converter current controller 、/> so as to achieve the purpose of current limiting. The current reference value is determined by using the current vector angle, so that fault current distribution is performed.
And then, when the power grid fails to recover or fails to reclose, the electric automobile charging pile recovers the network formation control operation again. And after the fault is recovered or when the fault reclosing failure occurs a permanent fault, recovering the grid-formed control of the electric automobile charging pile, maintaining the voltage source characteristic, realizing the emergency power supply support of the system and providing power for the key load.
Specifically, a control block diagram of the network-structured control strategy is shown in fig. 5, where Power calculation is power calculation; the LPF is a Low PASS FILTER, low-pass filter; VSG control is Virtual synchronous generator control, virtual synchronous machine control; voltage control is Voltage control; CSA is Current Saturation Algorithm, current saturation algorithm; current control is Current control; SVPWM modulator is Space Vector Pulse Width Modulation, space vector pulse width modulator; DRIVE SIGNALS is a driving signal. Three-phase voltage of filter capacitor of net-structured electric vehicle charging pile is obtained through voltage sensor and current sensor by net-structured electric vehicle charging pile 、/>、/> Grid-connected point three-phase current/> 、/>、/> Three-phase current of filter inductor/> 、/>、/> And inputting the electric signals into a controller of the grid-structured electric vehicle charging pile. Three-phase voltage, grid-connected point three-phase current and filter inductance three-phase current at filter capacitor of grid-structured electric vehicle charging pile />、/>、/>,/>、/>、/>、/>、/>、/>, Performing dq transformation to obtain/> 、/>、/> D-axis component/> And q-axis component/> ,/>、/>、/> D-axis component/> And q-axis component/> ,/>、/>、/> D-axis component/> And q-axis component/> The calculation formula is as follows:
In the method, in the process of the invention, And controlling the phase angle output of the second-order power synchronous loop for networking.
By means of 、/>、/> D-axis component/> And q-axis component/> ,/>、/>、/> D-axis component/> And q-axis component/> the calculation network type electric vehicle charging pile converter real-time output active Pe and reactive power Qe are sent into a power synchronous control loop of the network type electric vehicle charging pile converter after passing through a low-pass filtering link, and the calculation formula is as follows:
In the method, in the process of the invention, Is the cut-off frequency of the low pass filter and s is the laplace operator. And the components except the cut-off frequency are restrained through low-pass filtering, so that the stability of the system is improved.
The second-order power synchronous control frequency domain expression of the network-structured electric vehicle charging pile is as follows:
In the method, in the process of the invention, Is an active power reference value,/> is a damping coefficient,/> Is virtual moment of inertia,/> To output the angular frequency,/> The rated angular frequency of the power grid.
Further, the impedance of the power grid line is measured by taking a current injection method as an example, and a current signal with a certain frequency is injected into one end of the line to be measured. This typically involves injecting a current of known frequency into the line under test using a current source or injection transformer. At the other end of the line, a voltage sensor is used to measure the voltage response caused by the injected current. This voltage response contains information about the impedance of the line. The impedance of the line at the injection frequency can be calculated using the relationship between the injection current and the measured voltage. This typically involves the use of ohm's law in complex form, where impedance is the ratio of the phase and amplitude of the voltage and current. Calculating the R reactance X ratio of the line resistance according to the measurement result .
Further, when a grid voltage drop fault occurs, the electric vehicle charging pile is subjected to overcurrent, the electric vehicle charging is switched to be synchronous with the grid, and the current reference value of the grid-structured electric vehicle charging pile current controller is limited 、/> . According to the obtained ratio of R reactance X of the line resistance/> Determining current reference vector angle/> . When/> The grid line appears as an inductively set current reference vector angle/> and the electric automobile charging pile outputs reactive current to support the power grid voltage under the power grid voltage drop situation. When/> The grid line appears as resistive set current reference vector angle/> And the electric automobile charging pile outputs active current to support the power grid voltage under the power grid voltage drop situation. When/> it is necessary to set/>, based on specific gravity of line inductance and resistance .
Specifically, in the current limiting algorithm, a current reference value of a current controller of the charging pile converter of the electric automobile 、/> The limiting strategy of (2) is as follows:
Wherein,, For the current vector angle,/> D-axis current reference value output by the voltage loop; /(I) A q-axis current reference value output for the voltage loop; i max maximum allowable current amplitude preset for electric automobile charging pile converter,/> Is the d-axis current reference value of the converter,/> Is the q-axis current reference value of the current transformer. I max The maximum allowable current amplitude preset for the electric automobile charging pile current transformer, which is usually the preset value in the current transformer, can be set to be 1.2 or 1.5 times of rated current replication.
Wherein the control of the system after the current limiting strategy is adopted is shown in fig. 6. In the figure Z is the phase angle output of the phase-locked loop f For fault short-circuit resistance, omega 0 For the output angular frequency.
Open loop transfer function of phase locked loop The frequency domain expression of (2) is:
In the method, in the process of the invention, Is a proportional parameter of a phase-locked loop PI controller,/> S is the laplace operator of the transfer function, which is an integral parameter of the phase-locked loop controller.
Further, after the fault is recovered or when the grid fault reclosing fails to generate a permanent fault, the electric automobile charging pile is recovered to form a grid for control, the voltage source characteristic is maintained, the emergency power supply support of the system is realized, and power is provided for the key load.
The electric vehicle charging pile with the fault power grid supporting and emergency power supply functions provided by the embodiment of the application has the fault power grid supporting and emergency power supply functions, the voltage supporting capacity of the fault power grid of the electric vehicle charging pile is enhanced by determining the active and reactive components of the output current of the electric vehicle charging pile in the fault current limiting mode of the power grid according to the power grid line resistance-inductance ratio in the power grid fault, and the better power grid fault voltage supporting capacity can be provided in a self-adaptive manner according to the power grid condition. And when the power grid fault reclosing fails, the electric vehicle charging pile exits the fault current limiting mode to be in network construction control, and the external characteristics are represented by voltage source control, so that the electric vehicle charging pile can serve as a voltage source to supply power for a key load when the power grid fault loses power, and the electric vehicle charging pile supports the power grid emergency power supply function.
Specifically, when electric automobile fills electric pile normal operating: the electric automobile charging pile is a network control voltage source; during a fault: the electric automobile charging pile starts a fault current limiting mode to quickly support a power grid; failure of reclosing/loss of power from the grid: the fault current limiting mode exiting the CSA (Current Saturation Algorithm ) is conventional networking control, where the external characteristic is voltage source, and no additional control is required, as shown in fig. 5.
It should be understood that, although the steps in the flowcharts related to the embodiments described above are sequentially shown as indicated by arrows, these steps are not necessarily sequentially performed in the order indicated by the arrows. The steps are not strictly limited to the order of execution unless explicitly recited herein, and the steps may be executed in other orders. Moreover, at least some of the steps in the flowcharts described in the above embodiments may include a plurality of steps or a plurality of stages, which are not necessarily performed at the same time, but may be performed at different times, and the order of the steps or stages is not necessarily performed sequentially, but may be performed alternately or alternately with at least some of the other steps or stages.
Based on the same inventive concept, the embodiment of the application also provides a control method of the electric automobile charging pile, which comprises the following steps:
in response to detecting a power grid fault, determining a current reference value of a converter of the electric vehicle charging pile based on a current vector angle;
And adopting a follow-up control strategy, and carrying out fault current distribution based on the current reference value.
In one embodiment, the current vector angle is determined using the steps of:
Detecting line impedance of the electric automobile charging pile to obtain the ratio of line reactance and line resistance of the electric automobile charging pile;
based on the ratio, a current vector angle is determined.
In one embodiment, line impedance detection is performed on an electric vehicle charging pile to obtain a ratio of line reactance and line resistance of the electric vehicle charging pile, including:
Injecting current with preset frequency into a line to be tested;
Measuring a voltage response caused by the injected current using a voltage sensor at a voltage response location of the line; the voltage response includes impedance information of the line;
calculating the impedance of the line to be measured at a preset frequency based on the current and voltage responses; wherein, the impedance is the ratio of the phase and the amplitude of the voltage and the current;
and according to the impedance value, the ratio of the line reactance and the line resistance of the line to be tested is obtained.
In one embodiment, determining the current vector angle based on the ratio includes:
When (when) When determining that the current vector angle is/> ;
When (when) When determining that the current vector angle is/> ;
When (when) When determining that the current vector angle is/> And/> related to the specific gravity of the line inductance and the resistance of the electric automobile charging pile;
Wherein X is the line reactance, R is the line resistance, Is the ratio of the line reactance to the line resistance; /(I) Is the current vector angle.
In one embodiment, determining a current reference value of a current transformer of an electric vehicle charging pile based on a current vector angle includes:
The d-axis current reference value and the q-axis current reference value of the current transformer are determined based on the current vector angle by adopting the following expression:
Wherein,, For the current vector angle,/> D-axis current reference value output by the voltage loop; /(I) A q-axis current reference value output for the voltage loop; i max maximum allowable current amplitude preset for electric automobile charging pile converter,/> Is the d-axis current reference value of the converter,/> Is the q-axis current reference value of the current transformer.
In one embodiment, the method further comprises:
and in response to the detection of the recovery of the power grid fault or the detection of the reclosing failure of the power grid fault, adopting a grid-structured control strategy to control the current of the electric vehicle charging pile.
Based on the same inventive concept, the embodiment of the application also provides an electric vehicle charging pile control device for realizing the electric vehicle charging pile control method. The implementation scheme of the device for solving the problem is similar to that described in the above method, so the specific limitation in the embodiment of the electric vehicle charging pile control device or devices provided below may refer to the limitation of the electric vehicle charging pile control method hereinabove, and will not be repeated herein.
In an exemplary embodiment, as shown in fig. 7, there is provided an electric car charging pile control device 800 including:
The current reference value determining module 801 is configured to determine, in response to detecting a power grid fault, a current reference value of a current transformer of the electric vehicle charging pile based on a current vector angle;
The current distribution module 802 is configured to perform fault current distribution based on the current reference value by adopting a following-net type control strategy.
In one embodiment, the device further comprises an angle determining module for:
Detecting line impedance of the electric automobile charging pile to obtain the ratio of line reactance and line resistance of the electric automobile charging pile;
based on the ratio, a current vector angle is determined.
In one embodiment, the angle determination module is further configured to:
Injecting current with preset frequency into a line to be tested;
Measuring a voltage response caused by the injected current using a voltage sensor at a voltage response location of the line; the voltage response includes impedance information of the line;
calculating the impedance of the line to be measured at a preset frequency based on the current and voltage responses; wherein, the impedance is the ratio of the phase and the amplitude of the voltage and the current;
and according to the impedance value, the ratio of the line reactance and the line resistance of the line to be tested is obtained.
In one embodiment, the angle determination module is further configured to:
When (when) When determining that the current vector angle is/> ; /(I)
When (when) When determining that the current vector angle is/> ;
When (when) When determining that the current vector angle is/> And/> related to the specific gravity of the line inductance and the resistance of the electric automobile charging pile;
Wherein X is the line reactance, R is the line resistance, Is the ratio of the line reactance to the line resistance; /(I) Is the current vector angle.
In one embodiment, the current reference value determination module is further configured to:
The d-axis current reference value and the q-axis current reference value of the current transformer are determined based on the current vector angle by adopting the following expression:
Wherein,, For the current vector angle,/> D-axis current reference value output by the voltage loop; /(I) A q-axis current reference value output for the voltage loop; i max maximum allowable current amplitude preset for electric automobile charging pile converter,/> Is the d-axis current reference value of the converter,/> Is the q-axis current reference value of the current transformer.
In one embodiment, the method further comprises:
and the recovery module is used for carrying out current control on the electric vehicle charging pile by adopting a network construction control strategy in response to the detection of the recovery of the power grid fault or the detection of the reclosing failure of the power grid fault.
All or part of each module in the electric automobile charging pile control device can be realized by software, hardware and a combination thereof. The above modules may be embedded in hardware or may be independent of a processor in the computer device, or may be stored in software in a memory in the computer device, so that the processor may call and execute operations corresponding to the above modules.
In one embodiment, a computer readable storage medium is provided, having stored thereon a computer program which, when executed by a processor, implements the steps of the method described above.
In an embodiment, a computer program product is provided comprising a computer program which, when executed by a processor, implements the steps of the method described above.
Those skilled in the art will appreciate that implementing all or part of the above described methods may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed, may comprise the steps of the embodiments of the methods described above. Any reference to memory, database, or other medium used in embodiments provided herein may include at least one of non-volatile and volatile memory. The nonvolatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high density embedded nonvolatile memory, resistive random access memory (ReRAM), magneto-resistive random access memory (Magnetoresistive Random Access Memory, MRAM), ferroelectric memory (Ferroelectric Random Access Memory, FRAM), phase change memory (PHASE CHANGE memory, PCM), graphene memory, and the like. Volatile memory can include random access memory (Random Access Memory, RAM) or external cache memory, and the like. By way of illustration, and not limitation, RAM can be in various forms such as static random access memory (Static Random Access Memory, SRAM) or dynamic random access memory (Dynamic Random Access Memory, DRAM), etc. The databases referred to in the embodiments provided herein may include at least one of a relational database and a non-relational database. The non-relational database may include, but is not limited to, a blockchain-based distributed database, and the like. The processor referred to in the embodiments provided in the present application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic unit, a data processing logic unit based on quantum computing, or the like, but is not limited thereto.
The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The foregoing examples illustrate only a few embodiments of the application and are described in detail herein without thereby limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of the application should be assessed as that of the appended claims.
Claims (10)
1. The utility model provides an electric automobile fills electric pile that possesses trouble electric wire netting support and emergent power supply function which characterized in that includes the treater, the treater is used for realizing the following step:
In response to detecting a power grid fault, determining a current reference value of a converter of the electric vehicle charging pile based on a current vector angle;
And adopting a follow-up control strategy, and carrying out fault current distribution based on the current reference value.
2. The electric vehicle charging pile according to claim 1, characterized in that the current vector angle is determined using the steps of:
Detecting line impedance of the electric automobile charging pile to obtain the ratio of line reactance and line resistance of the electric automobile charging pile;
And determining the current vector angle based on the ratio.
3. The electric vehicle charging pile according to claim 2, wherein the detecting the line impedance of the electric vehicle charging pile to obtain a ratio of a line reactance and a line resistance of the electric vehicle charging pile comprises:
Injecting current with preset frequency into a line to be tested;
measuring a voltage response caused by the injected current using a voltage sensor at a voltage response location of the line; the voltage response includes impedance information of the line;
calculating the impedance of the line to be measured at a preset frequency based on the current and the voltage response; wherein, the impedance is the ratio of the phase and the amplitude of the voltage and the current;
And obtaining the ratio of the line reactance to the line resistance of the line to be tested according to the impedance value.
4. The electric vehicle charging stake of claim 2, characterized in that the determining the current vector angle based on the ratio includes:
When (when) When determining that the current vector angle is/> ;
When (when) When determining that the current vector angle is/> ;
When (when) When determining that the current vector angle is/> And/> Related to the specific gravity of the line inductance and the resistance of the electric automobile charging pile;
Wherein X is the line reactance, R is the line resistance, Is the ratio of the line reactance to the line resistance; /(I) Is the current vector angle.
5. The electric vehicle charging pile according to any one of claims 1 to 4, wherein determining the current reference value of the current transformer of the electric vehicle charging pile based on the current vector angle comprises:
The d-axis current reference value and the q-axis current reference value of the current transformer are determined based on the current vector angle by adopting the following expression:
Wherein,, For the current vector angle,/> D-axis current reference value output by the voltage loop; /(I) A q-axis current reference value output for the voltage loop; i max maximum allowable current amplitude preset for electric automobile charging pile converter,/> Is the d-axis current reference value of the converter,/> Is the q-axis current reference value of the current transformer.
6. The electric vehicle charging stake of claim 1, wherein the processor is further configured to implement the steps of:
And in response to the detection of the recovery of the power grid fault or the detection of the reclosing failure of the power grid fault, adopting a network construction control strategy to control the current of the electric automobile charging pile.
7. The method for controlling the charging pile of the electric automobile is characterized by comprising the following steps of:
In response to detecting a power grid fault, determining a current reference value of a converter of the electric vehicle charging pile based on a current vector angle;
And adopting a follow-up control strategy, and carrying out fault current distribution based on the current reference value.
8. An electric vehicle charging pile control device, characterized in that the device comprises:
The current reference value determining module is used for determining a current reference value of the current transformer of the electric vehicle charging pile based on a current vector angle in response to the detection of the power grid fault;
And the current distribution module is used for distributing fault current based on the current reference value by adopting a follow-up grid type control strategy.
9. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, implements the steps of the method of claim 7.
10. A computer program product comprising a computer program, characterized in that the computer program realizes the steps of the method of claim 7 when being executed by a processor.
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| CN202410276301.0A CN117895555A (en) | 2024-03-12 | 2024-03-12 | Electric automobile fills electric pile that possesses trouble electric wire netting and supports and emergent power supply function |
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| CN202410276301.0A CN117895555A (en) | 2024-03-12 | 2024-03-12 | Electric automobile fills electric pile that possesses trouble electric wire netting and supports and emergent power supply function |
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