A bidirectional ac-dc and unidirectional dc hybrid charging pile and inversion discharging method

Abstract

The application discloses a bidirectional AC / DC and unidirectional DC mixed charging pile and an inversion discharging method, which comprises a control system and a charging module; the charging module is in communication with the control system through a CAN bus, the charging module comprises a plurality of unidirectional DC modules and a plurality of bidirectional AC / DC modules; the bidirectional AC / DC modules are in pairs, the power of a single bidirectional AC / DC module is half of the power of a unidirectional DC module; the bidirectional AC / DC modules and the unidirectional DC modules are connected in parallel on the CAN bus; the charging module is connected with an EPS and emergency loads at an input end, and connected with a plurality of charging guns at an output end. The application mixes and controls the traditional unidirectional DC module and the bidirectional AC / DC module, expands the single charging function of the charging pile to vehicles, has the reverse discharging function of the new energy vehicle through the charging pile, realizes the V2L discharging function, saves the equipment cost, expands the equipment function, and greatly improves the resource utilization of the charging pile infrastructure.

Description

Technical Field

[0001] This invention belongs to the field of electric vehicle charging piles, and relates to a charging pile with bidirectional AC / DC and unidirectional DC hybrid charging and an inverter discharge method. Background Technology

[0002] With the popularization of new energy vehicles and the dense deployment of basic charging facilities, electric buses are gradually replacing fuel buses, and the number of new energy private cars is also rapidly increasing. Based on this, traditional AC charging has been gradually replaced by DC fast charging because of its slow charging speed. Only fast charging can meet people's fast-paced lifestyle.

[0003] On the one hand, there is a surge in the number of new energy electric vehicles, and on the other hand, there is a demand for high-power charging, which will further increase the pressure on the power grid. The introduction of peak-valley-flat electricity pricing and the implementation of "orderly electricity use" strategies in various regions also reflect the pressure on the power grid. New energy electric buses and private cars, equipped with DC fast charging, can be completely transformed into mobile backup power and energy storage devices, thus realizing the V2L (Vehicle to Load) function. Electric vehicles can be flexibly used as energy storage devices, enabling bidirectional energy interaction and emergency power supply with the power grid or electrical loads.

[0004] However, most of the charging piles currently in use are traditional unidirectional DC charging piles, which can only charge electric vehicles. To achieve V2L functionality, the entire pile needs to be replaced with bidirectional AC charging piles, which is too expensive and not conducive to the development of enterprises and the electric vehicle industry. Summary of the Invention

[0005] The purpose of this invention is to overcome the drawback of the high cost of replacing a unidirectional DC charging pile with a bidirectional AC charging pile in the prior art. It provides a charging pile that combines bidirectional AC / DC and unidirectional DC charging with an inverter discharge method, which saves equipment costs while expanding equipment functions and greatly improves the resource utilization rate of charging pile infrastructure.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] A charging pile that combines bidirectional AC / DC and unidirectional DC charging, including a control system and a charging module;

[0008] The charging module is connected to the control system via a CAN bus. The charging module includes multiple unidirectional DC modules and several bidirectional AC / DC modules. The bidirectional AC / DC modules are grouped in pairs, and the power of a single bidirectional AC / DC module is half the power of a unidirectional DC module. Both the bidirectional AC / DC modules and the unidirectional DC modules are connected in parallel on the CAN bus.

[0009] The charging module's input end is connected to an EPS and an emergency load, while the charging module's output end is connected to multiple charging guns.

[0010] Preferably, both the unidirectional DC module and the bidirectional AC / DC module are connected to a common AC bus on the AC side. On the DC side, the unidirectional DC modules are connected to the ring power distribution unit independently in sequence; the bidirectional AC / DC modules are connected in parallel in pairs and then connected to the ring power distribution unit as a group.

[0011] An inverter discharge method for a charging pile that combines bidirectional AC / DC and unidirectional DC power supply includes the following processes:

[0012] S1, the control system sets all bidirectional AC / DC modules for module DIP address recognition via broadcast;

[0013] S2, after the vehicle connects to one of the bidirectional AC / DC modules via the charging gun, the bidirectional AC / DC modules in that group are online, and the control system obtains the number of bidirectional AC / DC modules that are online in that group;

[0014] S3, the control system receives the number of replies from the bidirectional AC / DC modules, and then sets a relatively fixed group number based on the address of the online bidirectional AC / DC modules;

[0015] S4, after all bidirectional AC / DC modules with set group numbers respond to the group number in sequence, the control system queries the current group number of the online bidirectional AC / DC modules for verification and confirmation;

[0016] S5, the control system checks whether the current group number of all bidirectional AC / DC modules is consistent with the setting in S1. If they are inconsistent, it returns to S1. If they are consistent, it queries the number of bidirectional AC / DC modules in each group according to the group number.

[0017] S6, the control system compares the sum of the number of bidirectional AC / DC modules in all groups with the total number of bidirectional AC / DC modules obtained by the control system in S1. If the two match, the system parameters are configured. If the numbers do not match, the system returns to S1.

[0018] S7: After the parameters are configured, periodically query the total number of bidirectional AC / DC modules in the system. If the total number changes, return to S1 to reconfigure.

[0019] Preferably, in S4, the control system waits for the bidirectional AC / DC module to reply with the group number setting command; if the response times out, it returns to S1.

[0020] Preferably, the control system waits to query all online bidirectional AC / DC module group numbers, and returns to S1 if the timeout occurs.

[0021] Furthermore, the timeout period is 5 seconds.

[0022] Preferably, in S6, the parameter configuration includes the number of bidirectional AC / DC modules, module ID, module group number, module rated power, rated voltage, and rated current.

[0023] Preferably, in S1, the UPS provides power to the control system, and the control system is powered on.

[0024] Preferably, during inverter discharge, only the bidirectional AC / DC module is scheduled to operate, while the unidirectional DC module is stopped from being used.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] This invention combines a traditional unidirectional DC module with a bidirectional AC / DC module for hybrid control, expanding the charging pile's single-vehicle charging function to include reverse discharge capability for new energy vehicles. Based on the charging pile's fundamental charging functions, it achieves V2L discharge functionality, providing a feasible foundation for integrated photovoltaic, energy storage, charging, and discharging systems. This integrated charging and discharging capability, combined with the high-power charging characteristics of the DC charging pile, enables flexible peak-shaving and valley-filling effects, saving equipment costs while expanding equipment functionality. This significantly improves the resource utilization rate of charging piles as infrastructure. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the charging pile of the present invention, which combines bidirectional AC / DC and unidirectional DC charging.

[0028] Figure 2 This is a flowchart of the dynamic configuration process for inverter discharge of the charging pile according to the present invention;

[0029] Figure 3 This is a control flowchart of the control system of the present invention for the module;

[0030] Figure 4 This is a schematic diagram of the electrical circuit of the charging pile of the present invention. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0032] It should be noted that the terms “front,” “back,” “left,” “right,” “up,” and “down” used in the following description refer to the directions shown in the attached diagram, while the terms “inside” and “outside” refer to the directions toward or away from the geometric center of a specific component, respectively.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0034] like Figure 1 As shown, this is a charging pile that combines a bidirectional AC / DC module and a unidirectional DC module as described in this invention.

[0035] The charging system is composed of bidirectional AC / DC modules, which are replaced by unidirectional DC modules. The bidirectional AC / DC modules are grouped in pairs, and the power of a single bidirectional AC / DC module is half that of a unidirectional DC module.

[0036] The charging module is connected to the control system via a CAN bus, and both the bidirectional AC / DC module and the unidirectional DC module are connected in parallel on the CAN bus.

[0037] In terms of power connection: the unidirectional DC module and the bidirectional AC / DC module share a common AC bus on the AC side. On the DC side: the unidirectional DC module is connected to the ring power distribution unit independently in sequence; the bidirectional AC / DC module is connected in pairs in parallel and then connected to the ring power distribution unit as a group.

[0038] In terms of communication connectivity: The CMU (Central Control Unit) communicates and controls all modules and the PCU (Circular Distribution Unit) via the CAN1 bus. The CMU also communicates and controls each charging or charging / discharging unit via the CAN2 bus.

[0039] EPS and emergency loads are important loads for customers that cannot be powered off (such as control rooms). EPS is the customer's uninterruptible power supply, which can provide power to the customer's important loads for a period of time after the AC power grid fails. However, it cannot provide power for a long time. At this time, we use the vehicle to perform inverter discharge to provide AC power to the customer's important loads. If the power allows, it can also provide AC power to other loads of the customer.

[0040] For the two types of modules, control is handled independently, while module allocation and power distribution are uniformly scheduled. During charging, all modules participate in scheduling. During inverter discharge, only the bidirectional AC / DC modules are scheduled, while unidirectional DC modules are not used. Simultaneous charging and inverter discharge are not permitted in this system.

[0041] The terminal directly connected to the bidirectional AC / DC module is called the charging / discharging terminal. Considering the overall power loss of the equipment after a grid failure, the system needs emergency inverter discharge to ensure power supply. Therefore, the control system must have a backup uninterruptible power supply (UPS) to provide power after a grid failure. After the charging / discharging terminal receives DC power from the vehicle for the bidirectional AC / DC module, it performs inverter discharge to power the entire AC system.

[0042] like Figure 1 As shown, in this embodiment, based on a 360kW charging stack, 60kW unidirectional DC modules are replaced with bidirectional AC / DC modules to form a charging and discharging system that meets the 360kW charging requirement and can achieve 60kW inverter discharge. The 15kW bidirectional AC / DC modules are paired up to form a granular 30kW charging and discharging system.

[0043] Based on the traditional group charging system module configuration process combined with V2L application scenarios, the control system also faces the risk of restarting after a power outage on the AC grid side. After the control system restarts with UPS power, the system cannot identify available modules (including bidirectional AC / DC modules) due to the AC grid outage. At this point, only the vehicle can provide power to perform the inverter discharge function. Only after the vehicle acts as a power supply (DC) device on the DC side can the bidirectional AC / DC modules directly connected to it in the system operate, and only then can the control system identify available modules. After the inverter discharge, the AC side is powered on again, and the single-phase DC modules in the system, as well as the other bidirectional AC / DC modules not directly connected to it (the vehicle), begin to operate and join the system. Since the operating mode is inverter discharge, it is necessary to reconfigure the parameters of the newly added bidirectional AC / DC modules and incorporate power allocation and module scheduling for inverter discharge.

[0044] Figure 2 The diagram illustrates the dynamic configuration process of the bidirectional AC / DC module by the control system. Unlike the one-time configuration of traditional modules during the initial power-on phase, the bidirectional AC / DC module is dynamically configured because after a power outage, the system's charging / discharging terminal interacts with the vehicle (as a DC power supply device) and initially provides DC power to the bidirectional AC / DC module directly connected to that terminal. At this point, the system can only recognize one set of bidirectional AC / DC modules. After completing the module configuration and starting the inverter discharge, the inverter powers all modules in the system and adds them to the system. Therefore, the newly added modules also need to be configured accordingly; otherwise, the newly added modules will not be recognized by the control system. Thus, the bidirectional AC / DC module requires dynamic configuration.

[0045] Dynamic configuration process as follows Figure 2As shown, since the bidirectional AC / DC modules are grouped in pairs, in order to ensure the operability and stability of the system, the modules are set to use their own DIP switches as their addresses, and the bidirectional AC / DC modules 1# and 2# are set as group 11, and the bidirectional AC / DC modules 3# and 4# are set as group 12, which are connected to the addresses of the unidirectional DC modules from 1 to 10.

[0046] After configuring the bidirectional AC / DC modules, periodically check the number of modules in the system. If the number changes, reconfigure the bidirectional AC / DC modules. This ensures that newly added modules are recognized by the system and can participate in subsequent module control and invocation.

[0047] Instructions for dynamic configuration of bidirectional AC / DC modules during emergency inverter discharge:

[0048] 1. The UPS provides power to the control system. When the control system is powered on, it uses a broadcast method to set all bidirectional AC / DC modules for module DIP address identification.

[0049] 2. After the vehicle connects to one of the bidirectional AC / DC modules via the charging gun, the bidirectional AC / DC module group becomes online, and the control system obtains the number of online bidirectional AC / DC modules in that group.

[0050] 3. The control system receives the number of replies from the bidirectional AC / DC modules, and then sets a relatively fixed group number based on the address of the online bidirectional AC / DC modules.

[0051] 4. The control system waits for the bidirectional AC / DC module to respond to the group number setting command. If the response times out after 5 seconds, it returns to step one. After all the bidirectional AC / DC modules with set group numbers respond to the group number in sequence, the control system queries the online bidirectional AC / DC modules to verify and confirm the current group number.

[0052] 5. The control system waits to query the group numbers of all online bidirectional AC / DC modules. If the timeout is 5 seconds, it returns to step one, confirms that the current group number of all bidirectional AC / DC modules is consistent with the setting, and then queries the number of bidirectional AC / DC modules in each group according to the group number.

[0053] 6. The control system compares the sum of the number of bidirectional AC / DC modules within all groups with the total number of bidirectional AC / DC modules obtained by the control system in step 1. If the two match, the system parameters are configured. If the numbers do not match, the process returns to step 1.

[0054] The parameter configuration includes: the number of bidirectional AC / DC modules, module ID, module group number, module rated power, rated voltage, rated current and other single module parameters as well as the parameters of the whole group.

[0055] 7. After the parameters are configured, periodically check the total number of bidirectional AC / DC modules in the system. If the total number changes, reconfigure and go back to step 1.

[0056] Figure 3 This is a flowchart illustrating the system's module control process. The TMU (Terminal Management Unit) in the diagram represents the system's charging and discharging terminal. It interacts with the vehicle's BMS (Battery Management System) to obtain vehicle charging needs or discharging limits, and then provides this information to the CMU (Central Management Unit). The CMU allocates modules and power based on the charging and discharging needs or discharging limits provided by the charging and discharging terminal. Based on the allocated modules and power, the CMU controls the corresponding modules to perform rectified output or inverted discharge.

[0057] like Figure 3 The control process of the module shown is divided into 5 stages, as described below:

[0058] 1. Standby phase: When the module is idle, it is in standby mode. In this state, it performs real-time detection to see if there is a module power-on command. Once a module power-on command is detected, it jumps to the second phase, the module parameter setting phase.

[0059] 2. Module parameter setting stage: Preset the module's operating mode (rectification or inversion) according to the system's rectification and inversion operating modes. Set the module's output voltage and output current limits. After the module reports that all settings have taken effect, proceed to the third stage: module startup.

[0060] 3. Module startup stage: The module's operating parameters have been successfully set in the previous stage. In this stage, the control module is powered on and runs according to the preset parameters. This stage requires monitoring the external DC side voltage or the AC side voltage in inverter mode to check whether the module has completed the output of the set parameters. After determining that the module is outputting normally, the fourth stage, the module operation stage, begins.

[0061] 4. Module Operation Phase: During the operation phase, the system will dynamically adjust the output power of the module in real time according to the charging requirements or discharge power limit information provided by the terminal, and detect in real time whether there is a command to shut down the module. Upon receiving the module shutdown command, it will immediately enter the fifth phase, the module shutdown phase.

[0062] 5. Module shutdown phase: Set the module to be shut down to turn off the module output, and monitor whether the external output voltage of the module has been completely turned off. After the module output is completely turned off, return to the first phase and enter the module standby state.

[0063] Figure 4 This is the electrical schematic diagram of the main circuit of the charging pile that combines bidirectional AC / DC modules and unidirectional DC modules according to this application. The main circuit includes an AC part and a DC output part.

[0064] Interaction section:

[0065] The main unit uses a three-phase five-wire power grid input, which transmits power to various units within the system after metering, lightning protection, and AC / DC power distribution. The main circuit electrical schematic diagram is shown above.

[0066] DC output section:

[0067] Four bidirectional modules, each with a power of 60kW, replace the original 11# & 12# 30kW power modules and participate in the power distribution of the group charging system.

[0068] During normal charging, all modules participate in power distribution, and the power distribution unit delivers the rectified electrical energy from the modules to each charging terminal.

[0069] When the mains power fails, the vehicle-side inverter supplies power to the front end via the bidirectional module and powers the EPS. During normal charging, the N line of the power module is not connected to the system. During inverter discharge, KM1 is controlled to connect the N line to the system.

[0070] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0071] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this patent should not be determined by reference to the above description, but rather by reference to the foregoing claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the applicant has not considered that subject matter as part of the disclosed inventive subject matter.

Claims

1. An inverter discharge method for a charging pile that combines bidirectional AC / DC and unidirectional DC, characterized in that, The charging pile includes a control system and a charging module; The charging module is connected to the control system via a CAN bus. The charging module includes multiple unidirectional DC modules and several bidirectional AC / DC modules. The bidirectional AC / DC modules are grouped in pairs, and the power of a single bidirectional AC / DC module is half the power of a unidirectional DC module. Both the bidirectional AC / DC modules and the unidirectional DC modules are connected in parallel on the CAN bus. The charging module's input end is connected to an EPS and an emergency load, while the charging module's output end is connected to multiple charging guns. The inverter discharge method includes the following process: S1, the control system sets all bidirectional AC / DC modules for module DIP address recognition via broadcast; S2, after the vehicle connects to one of the bidirectional AC / DC modules via the charging gun, the bidirectional AC / DC modules in that group are online, and the control system obtains the number of bidirectional AC / DC modules that are online in that group; S3, the control system receives the number of replies from the bidirectional AC / DC modules, and then sets a relatively fixed group number based on the address of the online bidirectional AC / DC modules; S4, after all bidirectional AC / DC modules with set group numbers respond to the group number in sequence, the control system queries the current group number of the online bidirectional AC / DC modules for verification and confirmation; S5, the control system checks whether the current group number of all bidirectional AC / DC modules is consistent with the setting in S1. If they are inconsistent, it returns to S1. If they are consistent, it queries the number of bidirectional AC / DC modules in each group according to the group number. S6, the control system compares the sum of the number of bidirectional AC / DC modules in all groups with the total number of bidirectional AC / DC modules obtained by the control system in S1. If the two match, the system parameters are configured. If the numbers do not match, the system returns to S1. S7: After the parameters are configured, periodically query the total number of bidirectional AC / DC modules in the system. If the total number changes, return to S1 to reconfigure.

2. The inverter discharge method for a charging pile with bidirectional AC / DC and unidirectional DC hybrid operation according to claim 1, characterized in that, Both unidirectional DC modules and bidirectional AC / DC modules are connected to a common AC bus on the AC side. On the DC side, unidirectional DC modules are connected to the ring power distribution unit independently in sequence; bidirectional AC / DC modules are connected in pairs in parallel and then connected to the ring power distribution unit as a group.

3. The inverter discharge method for a charging pile with bidirectional AC / DC and unidirectional DC hybrid operation according to claim 1, characterized in that, In S4, the control system waits for the bidirectional AC / DC module to reply with the group number setting command. If the response times out, it returns to S1.

4. The inverter discharge method for a charging pile with bidirectional AC / DC and unidirectional DC hybrid operation according to claim 1, characterized in that, The control system waits to query all online bidirectional AC / DC module group numbers; if the timeout occurs, it returns to S1.

5. The inverter discharge method for a charging pile with bidirectional AC / DC and unidirectional DC hybrid charging as described in claim 3 or 4, characterized in that, The timeout period is 5 seconds.

6. The inverter discharge method for a charging pile with bidirectional AC / DC and unidirectional DC hybrid operation according to claim 1, characterized in that, In S6, the parameter configuration includes the number of bidirectional AC / DC modules, module ID, module group number, module rated power, rated voltage, and rated current.

7. The inverter discharge method for a charging pile with bidirectional AC / DC and unidirectional DC hybrid operation according to claim 1, characterized in that, In S1, the UPS provides power to the control system, and the control system is powered on.

8. The inverter discharge method for a charging pile with bidirectional AC / DC and unidirectional DC hybrid operation according to claim 1, characterized in that, During inverter discharge, only the bidirectional AC / DC modules are scheduled to operate, while the unidirectional DC modules are not used.

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