Self-adaptive online method for multiple direct-current charging piles

Abstract

The invention discloses a multi-direct-current charging pile self-adaptive online method, and belongs to the technical field of direct-current charging piles, and the method comprises the steps: connecting charging piles needing to be online, and setting an online mode; carrying out self-inspection on the online charging piles respectively; if self-inspection of the charging pile is normal, combined self-inspection is executed; executing a fault strategy when the charging pile passing the combined self-inspection fails; when the online power exceeds the gun line rated power of the charging gun, the maximum output power of the charging gun is limited; according to the multi-direct-current charging pile self-adaptive online method, when the current single-machine output power cannot meet the vehicle end requirement, whether an idle power supply module is used in an online pile or not is searched in a broadcast mode; after the online parameters are set, automatic broadcasting is carried out to construct the online topology, the single-machine output power is improved, the idle power module of the online charging pile is reasonably called on the basis of ensuring safe and reliable charging, and the charging efficiency is effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of DC charging piles, and in particular relates to a method for adaptively connecting multiple DC charging piles. Background Art

[0002] A DC charging station, as a charging device for electric vehicles, converts AC power into DC and delivers it to the vehicle battery at a higher power. Currently, to increase the output power of a single charging plug, DC charging stations primarily utilize a multi-module design. This stacking of power modules increases the rated power of each unit, thereby boosting the output of each charging plug. However, the charging process of electric vehicles is dynamic, and the power requested by the vehicle constantly changes as the battery SoC increases. To protect the battery and extend battery life, most electric vehicles currently switch from fast charging mode to slow charging mode when the battery SoC exceeds 80%, resulting in a decrease in power module utilization. To address this issue, various power distribution or flexible charging methods have been proposed, enabling the charging station to dynamically switch power modules based on the power requested by the vehicle at each plug.

[0003] Due to the uncertainty of charging pile usage, the utilization rate of charging piles varies at different times of the month and at different times of the day. Even large charging stations experience queues waiting for charging. However, in this situation of insufficient supply and demand, some charging piles often experience situations where some modules are dormant and not working because the vehicle is at the end of the charging phase and the requested power is low. At the same time, with the development of battery technology, vehicles that support higher charging power are becoming more common. However, the service life of a charging station after construction is generally around 10 years. Due to cost considerations, charging station service providers rarely upgrade existing facilities, unable to keep up with the charging power demand of the vehicle end. The charging pile power module is shut down at the end of the charging phase, resulting in low utilization rate and high cost of expanding existing charging piles. Therefore, it is necessary to develop a new adaptive connection method for multiple DC charging piles to solve the existing problems. Summary of the Invention

[0004] The object of the present invention is to provide a method for adaptively connecting multiple DC charging piles to solve the above-mentioned problems.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for adaptively connecting multiple DC charging piles, comprising:

[0006] A set of CAN communication lines, a set of output cables, and a set of joint contactors are added between the online charging piles. The online parameters are set through the human-machine interface (HMI interface) or remote control and sent to the SECC, which senses, builds, and maintains the online topology.

[0007] Based on the installation layout of charging piles at the charging station, a chain or ring connection structure is selected; a CAN communication line is added between the SECC of each charging pile to build an online communication topology; a set of combined contactors and output cables are added between each charging pile to build an online output topology and complete the electrical connection; a set of combined contactors and output cables includes two combined contactors and two output cables, and each cable requires a contactor;

[0008] Set the single-pile connection parameters through the HMI interface or remote control, including whether to enable the connection function, the connection topology, the maximum number of connections, and the current charging pile ID, and pass them to the SECC. The SECC then communicates with adjacent charging piles via the CAN line to build the topology.

[0009] The connected charging piles perform self-inspection respectively;

[0010] If the charging pile self-test is normal, a joint self-test will be performed;

[0011] Execute the fault strategy when a charging pile that has passed the joint self-test fails;

[0012] When the online power exceeds the rated power of the charging gun cable, the maximum output power of the charging gun is limited.

[0013] Preferably, the connected charging piles perform self-tests separately, performing the following steps:

[0014] N i Indicates that the current charging pile is the i-th charging pile among the total N connected charging piles, with N ia represents the charging gun A of the i-th charging pile, with N ib represents the charging gun B of the i-th charging pile, with K ia_out Indicates N i The first output contactor of the charging gun A of the charging pile to the power module controls the power output of the power module to the charging gun A, with K i_m1m2 Indicates N i The parallel contactor between the power module M1 and the power module M2 of the charging pile controls the on and off of the adjacent power modules. First, all the output contactors and the parallel contactor are controlled to close and open in sequence, and the feedback signal of each contactor is read. When the feedback signal is consistent with the control state, the contactor action detection passes, otherwise the corresponding fault is triggered. Then close K ia_out The SECC of the i-th charging pile sends a discharge command to all the power modules of the pile, and reads whether the voltage of the meter of charging gun A is consistent with the voltage of the power module. If the values are consistent, the self-test of charging gun A passes, otherwise the fault is triggered; the same applies to charging gun B.

[0015] Preferably, if the self-test of the charging pile is normal, a joint self-test is performed, and the following steps are performed: the joint contactor between the two piles is controlled to close and open by the previous charging pile, and the contactor feedback signal is read; when the feedback signal is consistent with the control state, the contactor detection passes, otherwise the joint self-test fails; then the previous charging pile will close the joint contactor between its own right charging gun and the module of the next charging pile, and send a power module discharge command to the SECC of the next charging pile through the CAN line, and the next charging pile will wake up the first power module to discharge. The purpose of this process is to detect whether the cable between the two piles is normally connected; at this time, the previous charging pile will read the meter voltage of the right charging gun and compare it with the power module voltage. If the voltage is consistent, the joint self-test passes, otherwise the joint self-test fails; the control state is on and off.

[0016] Preferably, when a charging pile that has passed the joint self-inspection fails, the following steps are performed: the charging pile that currently fails will send fault information to the charging pile connected to the charging gun according to the location of the faulty charging gun, and at the same time set the online status of the link (output cable) to unavailable; the adjacent charging pile will also update its own online topology after receiving the fault information, and set the online status of the link to unavailable; when the fault of the faulty charging pile is restored, the charging pile will send charging gun information to the adjacent charging pile, and the adjacent charging pile will re-perform a joint self-inspection with the charging pile after receiving the information, and restore the online status of the link after the joint self-inspection passes.

[0017] Preferably, when the online power exceeds the rated power of the charging gun line, the following steps are performed: the OCPP limits the maximum output power of the charging gun according to the rated power of the charging gun line, and sends the limit value to the SECC; when the vehicle-side EVCC requests power greater than the rated power of the charging gun line, the power is output according to the maximum output power limit value of the charging gun.

[0018] Preferably, when constructing the topology: i_comb Indicates N i Charging pile and N i+1 The joint contactor between the charging piles; when N i When the charging pile passes the self-test and the online function is enabled, it sends a signal to N i+1 Charging pile N i+1 The power module of the charging pile; in the joint self-test phase, first close N ib Charging gun to N i+1a The joint contactor between the charging guns determines whether the joint contactor between the single piles can work normally; then close N ib Charging gun to N i+1a The joint contactor between the charging guns controls N i+1 The charging pile power module discharges, and N ib The meter of the charging gun reads the voltage data, N iThe charging pile SECC receives N through the CAN bus i+1 The power module discharge data sent by the charging pile SECC is compared with the data read by its own meter to determine whether the voltage is consistent, and finally complete the joint self-test.

[0019] Preferably, after the topology is established, when N i+1a When the charging gun fails, N i+1 The charging pile will transmit N i+1a Charging gun fault information is synchronized to N i Charging pile, at this time N i The charging pile will place itself N ib The charging gun node is offline. ib The charging gun will not charge N i+1 The charging pile calls the power module; similarly, when N ib When the charging gun fails, N i The charging pile will transmit N ib Charging gun fault information is synchronized to N i+1 Charging pile, N i+1 The charging pile will place itself N i+1a The charging gun node is offline. i+1a The charging gun will not charge N i Charging pile calling module;

[0020] When the fault is restored, N i Charging pile and N i+1 The charging pile will re-run the joint self-test and restore N after passing the self-test. ib Charging gun and N i+1a Charging gun node status.

[0021] Preferably, when there are n charging piles online, P i Represents the rated power of the i-th charging pile. After completing the joint self-test, each online charging pile SECC reports the rated power to the OCPP. The sum of the reported rated powers is the maximum online power, that is,

[0022] Preferably, when the maximum online power exceeds the rated power of the charging gun line, the maximum power limit issued by OCPP includes:

[0023] P t Indicates the current maximum output power of N combined charging piles, expressed as P ia Indicates the maximum output power of the i-th charging pile gun A. When P t Greater than P ia When N i The charging pile will issue restrictions to SECC through OCPP, limiting N iaThe maximum charging power of the charging gun is P ia , when N ia The charging gun is inserted to start charging. If the vehicle's requested power is greater than P ia And N ia The output power that the charging gun can obtain through online connection is also greater than P ia , through the maximum power limit, N ia The output power of the charging gun will not exceed P ia , to prevent N ia The charging gun wire melted due to overload. The power is greater than P ia And N ia The output power that the charging gun can obtain through online connection is also greater than P ia , through the maximum power limit, N ia The output power of the charging gun will not exceed P ia , to prevent N ia The charging gun cable melted due to overload.

[0024] Preferably, when connected in a chain, a maximum of N-1 charging guns are supported to increase the output power by being connected simultaneously; when connected in a ring, a maximum of N charging guns are supported to increase the output power by being connected simultaneously.

[0025] The technical effects and advantages of the present invention are as follows: the adaptive online method for multiple DC charging piles, when the current output power of a single machine cannot meet the needs of the vehicle end, broadcasts to find whether there is an idle power module for use in the online pile; after the online parameters are set, it automatically broadcasts to build an online topology to improve the output power of the single machine; and supports any number of charging piles to be online and chain and ring topology switching. On the basis of the chain topology, only one set of contactors and output lines needs to be added, and the connection topology can be switched to a ring structure by setting it to a ring type through the HMI interface or remote control. On the basis of the ring topology, only the connection topology can be switched to a chain structure by setting it to a chain type through the HMI interface or remote control. When an online node is in an abnormal state, the abnormal state can be detected immediately and the node can be taken offline to avoid danger. At the same time, when the abnormal state is restored, After recovery, it can automatically restore the online status by performing a joint self-test again without human intervention; when the total online rated power exceeds the rated output power of the charging gun line, the maximum output power of the charging gun line is limited to avoid overheating and burning of the charging gun line; each charging pile can be connected by adding only one set of communication cables, one set of output cables and one set of relays to complete the online construction; the online parameters can be set through the HMI interface or remote control to freely control the number of connections and the online structure; and SECC adds an online self-test function and status sharing between charging piles to improve the reliability of the online function without human intervention; for the situation where the online power exceeds the gun line carrying capacity, OCPP intelligently limits the maximum output capacity of the charging gun to avoid it. On the basis of ensuring safe and reliable charging, the idle power modules of the online charging piles are reasonably called to effectively improve the charging efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the process of the present invention;

[0027] Figure 2 This is a schematic diagram of the chain electrical connection of the present invention;

[0028] Figure 3 This is a schematic diagram of the ring-type electrical connection of the present invention.

[0029] In the figure: 11, first output contactor; 12, second output contactor; 21, parallel contactor; 31, combined contactor. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] The present invention provides Figure 1 A method for adaptively connecting multiple DC charging piles is shown in the figure. The terms in the scheme are explained as follows:

[0032] EVCC stands for Electric Vehicle Communication Controller, which is used to communicate with external charging equipment (such as charging piles);

[0033] SECC stands for Supply Equipment Communication Controller and is used for vehicle-side communication, power scheduling, etc.

[0034] OCPP stands for Open Charge Point Protocol, which is used for communication between charging piles and backend management systems, and also communicates with SECC to implement charging control;

[0035] The output contactor includes: a first output contactor 11 and a second output contactor 12. The first output contactor 11 and the second output contactor 12 are used to control the on / off between the power module M1 and the power module M2 and the two charging guns A and B, respectively. ia_out and K ib_out express;

[0036] The parallel contactor 21 is used to control whether the power modules are connected in parallel. i_m1m2 express;

[0037] The combined contactor 31 is used to control whether the charging piles are connected to each other. i_comb express;

[0038] This embodiment is a method for connecting three two-stage charging piles, which specifically includes the following steps:

[0039] S1: The SECCs of the three charging piles are connected via CAN lines to build a CAN communication network. Each charging pile contains two charging guns and four power modules. The fourth power module of the previous charging pile is connected to the first power module of the next charging pile with a cable, and a set of contactors is added to the cable. Due to the ring connection, the fourth power module of the last charging pile will be connected to the first power module of the first charging pile, thus completing the electrical wiring. Figure 2 As shown, when connected in chain, it supports up to N-1 charging guns to increase output power at the same time; Figure 3 As shown in the figure, when connected in a ring, it supports up to N charging guns to increase the output power by connecting them simultaneously.

[0040] S2: Power on all charging piles that need to be connected. After powering on, each charging pile will perform self-test.

[0041] S21. Sequentially close the output contactor of the charging pile and the parallel contactor 21, and detect the contactor feedback status to determine whether the contactor is working properly. When the feedback status is inconsistent with the control status, the fault severity will be classified according to the contactor level. When the output contactor is abnormal, the charging gun status will be set to unavailable. When the parallel contactor 21 is abnormal, the contactor status will be set to unavailable, which will not affect the charging gun's availability.

[0042] S22: Close the first output contactor 11 and all parallel contactors 21 connecting charging gun A to the power module, control the power module to discharge, read the meter voltage of charging gun A, and compare the power module voltage with the meter voltage. If the voltages match, charging gun A passes the self-test; if the voltages do not match, charging gun A fails the self-test and triggers a fault. All contactors are then disconnected. Charging gun B repeats the above process. After the charging pile completes its self-test, the power module goes into sleep mode.

[0043] S3: OCPP transmits the connection parameters to SECC via the network cable, informing SECC whether to enable the connection function, the maximum number of connections, and the ID of the charging pile. When the connection function is enabled, the SECCs of two adjacent charging piles will share their self-test status via the CAN line. Figure 3 Taking the charging pile 1 and the charging pile 2 as an example, when the charging gun B of the charging pile 1 passes the self-test and the charging gun A of the charging pile 2 passes the self-test, step S4 is executed, otherwise the joint self-test fails.

[0044] S4: Charging gun 1 controls its combined contactor 31 to close and open, and reads the feedback signal from combined contactor 31. If the feedback signal matches the control state, the combined contactor 31 actuation test passes; otherwise, the combined self-test fails. Charging pile 1 then closes its combined contactor 31 and sends a power module discharge command to the SECC of charging pile 2 via the CAN line, which wakes up the power module and discharges. At this point, charging pile 1 reads the meter data from charging gun B and compares it with the power module data. If the data matches, the combined self-test passes; otherwise, the combined self-test fails.

[0045] In one embodiment, if the charging pile passes the joint self-test, the following steps are performed:

[0046] S5: Each charging pile's SECC accumulates the rated power of the charging pile that passes the joint self-test and reports the power to the central controller, which updates the maximum power on the HMI interface to the online power. If the online power exceeds the rated power of the charging gun line, the central controller will limit the maximum output power of the charging gun to the rated power of the gun line.

[0047] In one embodiment, if charging gun B of the online charging pile 2 starts charging, the following steps are performed:

[0048] The SECC of charging pile 2 establishes communication with the vehicle-side EVCC to negotiate charging parameters. When the remaining output power of charging pile 2 is greater than the EVCC's required power, the online power module will not be called. When the remaining output power of charging pile 2 is less than the EVCC's required power, the SECC will read the status of charging gun A of charging pile 2 and the status of charging gun B of charging pile 1. If the status of charging gun A of charging pile 2 or charging gun B of charging pile 1 is unavailable, it means that the online link from charging pile 2 to charging pile 1 is unavailable. The SECC will then read the status of charging gun A of charging pile 3. If the status of charging gun A is unavailable, it means that the online link from charging pile 2 to charging pile 3 is unavailable, and the online output has failed. The maximum output power of charging gun B of charging pile 2 is the remaining output power of charging pile 2. If one of the links is available, charging gun B of charging pile 2 will notify the SECC on the link of the additional power request according to this link until the vehicle-side required power is met. If both links are available, the SECC of charging pile 2 will follow the shortest path principle and give priority to calling the power module closest to charging gun B until the power demand of the vehicle is met.

[0049] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for adaptively connecting multiple charging piles, characterized by: include: Connect the charging station that needs to be connected and set the online mode; The connected charging piles perform self-inspection respectively; If the charging pile self-test is normal, a joint self-test will be performed; Execute the fault strategy when a charging pile that has passed the joint self-test fails; When the online power exceeds the rated power of the charging gun cable, the maximum output power of the charging gun is limited.

2. The method for adaptively connecting multiple charging piles according to claim 1, characterized in that: The charging piles that need to be connected include: The SECC of each charging pile that needs to be connected is connected via a CAN communication line; A set of joint contactors and output cables are respectively provided between the charging piles; Any charging pile sets the charging pile connection parameters, and after the settings are completed, they are sent to the SECC of the connected charging pile.

3. The method for adaptively connecting multiple charging piles according to claim 2, characterized in that: The online parameters include: Whether the online function is enabled, the online topology, the maximum number of connections, and the current charging pile ID.

4. The method for adaptively connecting multiple charging piles according to claim 1, characterized in that: The online modes include: The ring structure includes: all charging piles involved in the connection are connected in series to form a closed loop structure; The chain structure includes: all charging piles involved in the connection are connected in series.

5. The method for adaptively connecting multiple charging piles according to claim 4, characterized in that: All the charging piles involved in the connection are connected in series to form a closed-loop structure, including: each power module of each charging pile is connected in parallel, the last power module of the first charging pile is connected to the first power module of the second charging pile, the remaining charging piles are connected in sequence, and the last power module of the last charging pile is connected to the first power module of the first charging pile.

6. The method for adaptively connecting multiple charging piles according to claim 1, characterized in that: The self-test of the online charging piles includes: closing and opening all contactors of the charging piles in sequence, detecting the feedback status of all contactors, and judging whether all contactors are working normally. When the feedback status is consistent with the control status, the contactor action detection is successful; When the feedback status is inconsistent with the control status, the fault type will be analyzed according to the contactor type.

7. The method for adaptively connecting multiple charging piles according to claim 6, characterized in that: When the feedback state is inconsistent with the control state, the fault type will be analyzed according to the contactor type, including: When the output contactor is abnormal, the charging gun connected to the output contactor is unavailable; When the parallel contactor between the power modules is abnormal, the parallel contactor status is set to unavailable; Close the output contactor and parallel contactor to control the power module to discharge. Read and compare the power module discharge voltage and the meter voltage reading. If the power module discharge voltage and the meter voltage reading are consistent, the charging cable connected to the power module and the meter is discharging normally. When the discharge voltage of the power module is inconsistent with the voltage reading of the charging gun meter, the charging gun connected to the meter is set to unavailable. After the detection is completed, the power module is put into sleep mode and all contactors are disconnected.

8. The method for adaptively connecting multiple charging piles according to claim 1, characterized in that: If the charging pile self-test is normal, performing the joint self-test includes: The charging pile controls the closing and opening of the combined contactor and reads the combined contactor feedback signal; When the feedback signal is consistent with the control state, the combined contactor test passes, otherwise the combined self-test fails; the charging pile closes the combined contactor and sends a discharge signal to the other charging pile connected to the combined contactor via the CAN communication line. The charging pile that receives the discharge signal wakes up the power module connected to the sending discharge signal to discharge; The charging pile that sends the discharge signal reads the meter voltage data of its own charging gun and compares it with the voltage data of the power module that receives the discharge signal. If the meter voltage data is consistent with the power module voltage data, the joint self-test passes, otherwise the joint self-test fails.

9. The method for adaptively connecting multiple charging piles according to claim 1, characterized in that: When a charging pile that has passed the joint self-test fails, executing the fault strategy includes: the currently failed charging pile will send fault information to the charging pile connected to the charging gun according to the location of the failed charging gun, and at the same time set the link status between the failed charging gun and the connected charging pile to unavailable; The charging pile that receives the fault information updates its own connection topology and sets the connection status of the link between the faulty charging gun and the charging pile to unavailable; When the fault of the faulty charging pile is restored, the restored charging pile will send charging gun fault recovery information to the connected charging pile. The charging pile that receives the charging gun fault recovery information will re-perform a joint self-test. After the joint self-test passes, the link online status will be restored.

10. The method for adaptively connecting multiple charging piles according to claim 1, characterized in that: When the online power exceeds the rated power of the charging gun line, limiting the maximum output power of the charging gun includes: OCPP limits the maximum output power of the charging gun according to the rated power of the charging gun line, and sends the limit value to SECC. When the vehicle-side EVCC requests power greater than the rated power of the charging gun line, the charging gun is output according to the maximum output power limit value.

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