A star chain type double-gun direct current pile capable of multi-machine parallel charging

Abstract

The utility model relates to electric automobile charging facility technical field discloses a kind of double-gun direct current piles of star chain type multiple machine parallel charging, including pile body, ac input unit, rectifier module group, direct current output unit, first charging gun and second charging gun, it is characterized by: the ac input unit includes the moulded case circuit breaker and ac contactor connected in turn, for accessing and controlling three-phase ac power supply;The rectifier module group is constituted by four independent rectifier modules in parallel, and its input end is accessed three-phase ac power through the ac contactor, and its output end accesses the direct current output unit.In the utility model, through the synergic working of power distribution controller, bus contactor group and parallel interface unit, the power of multiple direct current piles is integrated into a unified power sharing pool, and the controller can intelligently and dynamically allocate power from the pool according to the real-time demand of the connected vehicle, greatly improving the utilization rate and overall operation efficiency of the charging pile.

Description

Technical Field

[0001] This utility model relates to the field of electric vehicle charging facilities technology, and in particular to a star-chain type dual-gun DC charging pile that can be used for parallel charging of multiple units. Background Technology

[0002] With the development of battery technology, electric vehicles are demanding increasingly faster charging speeds. Traditional integrated DC charging piles have limited power, making it difficult to meet the needs of high-power fast charging. Multi-unit parallel DC charging piles can combine the power of multiple charging piles for output, greatly improving the charging speed and meeting the fast charging requirements of electric vehicles. Using independent ventilation modules increases the overall reliability of the charging pile, improves the overall protection level, and also solves the noise problem.

[0003] Firstly, traditional integrated DC charging stations are typically designed with fixed configurations and power outputs, resulting in poor flexibility. They cannot intelligently and dynamically adjust to the actual charging needs of vehicles. When encountering vehicles with low charging power requirements, this leads to wasted power. For example, if a vehicle requiring only 50kW of charging power is connected to a 150kW integrated charging station, the excess 100kW power remains idle, reducing the utilization rate of the charging station. Conversely, when encountering vehicles with high power demands, the charging station cannot meet their requirements, resulting in slow charging speeds and poor adaptability. This reduces customer satisfaction with the charging station and decreases the revenue of charging station operators. With the development of electric vehicle technology and users' increasing demands for charging speed, this power limitation is becoming increasingly apparent, affecting the practicality and market competitiveness of charging stations.

[0004] Secondly, traditional integrated DC charging piles use conventional air-cooled modules, which have densely packed internal components and limited heat dissipation space, resulting in low heat dissipation efficiency. Under high load operation or high temperature environments, overheating is prone to occur, affecting the service life and operational stability of the equipment and increasing the probability of failure.

[0005] More importantly, increasing the overall power of traditional integrated DC charging piles requires large-scale modifications to the entire device, and even replacement of core components. This is not only complex but also incurs high upgrade costs. Moreover, during the upgrade process, the charging pile cannot provide charging services normally, affecting operational efficiency. Utility Model Content

[0006] To overcome the above shortcomings, this utility model provides a star-chain type dual-gun DC charging pile that can be connected in parallel for multiple units. It aims to improve the existing technology where increasing the overall power of traditional integrated DC charging piles requires large-scale modification of the entire equipment, or even replacement of core components, which is not only complicated to operate but also generates high upgrade costs.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a star-chain type dual-gun DC charging pile that can be charged in parallel with multiple units, including a pile body, an AC input unit, a rectifier module group, a DC output unit, a first charging gun and a second charging gun. The AC input unit includes a molded case circuit breaker and an AC contactor connected in sequence, which are used to connect to and control a three-phase AC power supply. The rectifier module group consists of four independent rectifier modules connected in parallel. Its input terminal is connected to three-phase AC power through the AC contactor, and its output terminal is connected to the DC output unit. The DC output unit includes a DC output high voltage box, a DC output copper busbar disposed inside the high voltage box, and a busbar contactor group and a gun line output contactor group disposed on the DC output copper busbar. The DC pile is also equipped with a parallel interface unit, which includes a set of parallel contactors. The input end of the parallel contactor is connected to the DC bus between the bus contactor group and the gun line output contactor group, and its output end is led to the external parallel connection terminal on the pile body. The charging pile also includes a power distribution controller, which is connected to the protocol conversion board of multiple rectifier modules and the first and second charging guns via a CAN bus, and is electrically connected to the drive coils of the AC contactor, the bus contactor group, the gun line output contactor group and the parallel contactor via control lines, for controlling the on and off of each contactor according to the charging needs of the vehicle.

[0008] The above technical solution enables the construction of an intelligent power distribution system with a power distribution controller at its core, which greatly improves the power utilization rate and operational flexibility of charging equipment. It can accurately and dynamically distribute power within a single charging pile and among multiple charging piles according to vehicle demand, thereby effectively solving the contradiction between high-power fast charging demand and low equipment utilization. At the same time, the modular parallel design provides charging stations with smooth and low-cost power expansion capabilities.

[0009] As a further description of the above technical solution: The busbar contactor group includes multiple sets of DC output contactors for controlling the outputs of the multiple rectifier modules to be combined on the DC output copper busbar. The gun line output contactor group includes a first gun output contactor group for controlling the on / off state of the first charging gun and a second gun output contactor group for controlling the on / off state of the second charging gun. The rectifier module group consists of four 60kW independent duct rectifier modules connected in parallel, and its output terminal is connected to the high-voltage wall terminal of the DC output high voltage box through positive and negative wires.

[0010] The above technical solution employs four 60kW modules connected in parallel, ensuring the hardware foundation for a high power output of 240kW. This achieves modular power stacking, while the independent air duct design ensures efficient heat dissipation and physical isolation of each module under high load, effectively avoiding thermal interference and improving the long-term operational reliability, stability, and protection level of the entire pile. It also creates conditions for reducing operating noise.

[0011] As a further description of the above technical solution: The busbar contactor group includes three sets of DC output contactors. The switching on and off of the DC output contactors is used to divide the DC output copper busbar into four segments and control whether the output of each rectifier module can be combined.

[0012] The above technical solution transforms the DC copper busbar into a series of flexibly programmable power buses, enabling dynamic combination and intelligent allocation of the output power of the four rectifier modules within a single charging pile. This allows for various power distribution modes, from equal output to centralized power supply, between the two charging guns, based on the charging needs of different vehicles, greatly improving the power utilization efficiency of a single charging pile and its adaptability to charging scenarios.

[0013] As a further description of the above technical solution: The parallel interface unit includes a set of parallel contactors, namely a positive parallel contactor and a negative parallel contactor, and the external parallel connection terminals include a first reserved connection point, a second reserved connection point, a third reserved connection point and a fourth reserved connection point.

[0014] The above technical solution constitutes a universal hardware interface for electrical interconnection between multiple DC charging piles. This structure enables the DC power buses of each DC pile to quickly form a network through cross-connection, forming a unified shared power pool, thereby realizing cross-pile integration and flexible expansion of charging pile power resources.

[0015] As a further description of the above technical solution: The input terminal of the positive parallel contactor is led out from before the positive fuse of the first gun output contactor group, and the output terminal is connected to the first reserved wiring point. The input terminal of the negative parallel contactor is led out from before the negative shunt of the second gun output contactor group, and the output terminal is connected to the third reserved wiring point.

[0016] Through the above technical solution: the input terminal of the positive parallel contactor K9 is set before the positive fuse of the first output contactor group, so that the parallel output circuit is also protected by the fuse, effectively preventing the impact of fault current when the external line is short-circuited. At the same time, the input terminal of the negative parallel contactor K10 is set before the negative shunt of the second output contactor group, ensuring that the parallel current flowing in or out through K10 can be accurately measured by the shunt, thereby realizing the measurability and controllability of parallel power. This design provides reliable current feedback information for the power distribution controller to perform precise power scheduling while ensuring the electrical safety of the system.

[0017] As a further description of the above technical solution: The second reserved wiring point is led out from the copper busbar between the positive contactor of the second gun output contactor group and the corresponding positive contactor in the busbar contactor group, and the fourth reserved wiring point is led out from the copper busbar between the negative contactor of the second gun output contactor group and the corresponding negative contactor in the busbar contactor group.

[0018] Through the above technical solution, the reserved connection points XT13-2 and XT13-4 are precisely led to the key nodes of the DC bus of the second charging gun, so that the parallel power input from the outside can be directly fed into the DC bus network of this pile. This allows the external power to either directly power the second charging gun through the second gun contactor or be fed back into the bus through the busbar for use by the first charging gun. This greatly enhances the flexibility and path diversity of the external power scheduling within this pile, while keeping this part of the current within the monitoring range of the metering and protection system, providing a structural foundation for building an efficient and reliable bidirectional power interaction network.

[0019] As a further description of the above technical solution: The AC input unit also includes a first branch circuit and a second branch circuit. The first branch circuit is connected in sequence to a miniature circuit breaker and a surge protector, and is led out from the input terminal of the molded case circuit breaker to protect against grid impact and lightning instantaneous current. The second branch circuit is led out from the input terminal of the molded case circuit breaker and is connected in sequence to a residual current device and an auxiliary power supply. The auxiliary power supply is an AC / DC switching power supply module, which is used to convert single-phase AC power into DC power to supply power to the power distribution controller and the pile control system.

[0020] The above technical solution, employing a first branch circuit and a second branch circuit, jointly constructs an auxiliary protection system for the charging pile. The first branch circuit provides lightning and surge protection at the grid-side inlet, effectively suppressing transient overvoltages from the grid and ensuring the safe operation of downstream power modules. The second branch circuit provides an independent, safe, and stable low-voltage DC power supply for the control system, ensuring reliable operation of the power distribution controller and various low-voltage electrical appliances under various operating conditions. The two circuits work together to comprehensively improve the electrical safety and operational reliability of the entire charging pile from two dimensions: resisting external grid disturbances and ensuring the stability of the internal control center.

[0021] As a further description of the above technical solution: The power distribution controller is also connected to a human-machine interface screen via an RS232 communication line for parameter setting and status display, and is connected to a card reader via another independent RS232 communication line for processing charging transactions.

[0022] Through the aforementioned technical means, an independent RS232 communication channel can be configured for the power distribution controller to connect to the human-machine interface screen and the card reader respectively, thus constructing a functionally decoupled and stable dual human-machine interface. This not only realizes intelligent management of real-time monitoring of charging status and flexible configuration of equipment parameters, but also completes a complete commercial service closed loop from user identity authentication, charging control to fee settlement. This not only improves the user's operating experience and transparency, but also provides technical support for the unmanned operation and commercial application of charging piles.

[0023] This utility model has the following beneficial effects: 1. This utility model integrates the power of multiple DC charging piles into a unified power sharing pool through the coordinated work of a power distribution controller, a bus contactor group, and a parallel interface unit. The controller can intelligently and dynamically allocate power from the pool according to the real-time needs of the connected vehicles, solving the problem of power waste when facing vehicles with low power demand and insufficient capacity when facing vehicles with high power demand in traditional fixed power charging piles, thereby greatly improving the utilization rate and overall operating efficiency of charging piles.

[0024] 2. This utility model allows charging operators to connect multiple charging piles in parallel to form a network according to business growth needs through simple cable connections, smoothly increasing the total output power of the site. This avoids the high cost and construction complexity of replacing the entire charging pile or core components to upgrade the power in traditional solutions, and realizes on-demand expansion and rapid deployment. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a star-chain type dual-gun DC charging pile that can be connected in parallel for multiple units, as proposed in this utility model. Figure 2 A schematic diagram of the human-computer interaction display architecture for a star-chain type dual-gun DC charging pile that can be connected in parallel for multiple units, as proposed in this utility model; Figure 3 This is a schematic diagram of the system architecture of a star-chain type dual-gun DC charging pile that can be connected in parallel for multiple units, as proposed in this utility model. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0027] Reference Figures 1-3 The present invention provides an embodiment of a star-chain type dual-gun DC charging pile that can be charged in parallel with multiple units, including a pile body, an AC input unit, a rectifier module group, a DC output unit, a first charging gun and a second charging gun. The AC input unit includes a molded case circuit breaker and an AC contactor connected in sequence for connecting and controlling a three-phase AC power supply. The rectifier module group consists of four independent rectifier modules connected in parallel. Its input terminal is connected to three-phase AC power through an AC contactor, and its output terminal is connected to a DC output unit. The DC output unit includes a DC output high voltage box, a DC output copper busbar installed inside the high voltage box, and a busbar contactor group and a gun line output contactor group installed on the DC output copper busbar; DC piles are also equipped with a parallel interface unit, which includes a set of parallel contactors. The input end of the parallel contactor is connected to the DC bus between the bus contactor group and the gun line output contactor group, and its output end is led to the external parallel connection terminal on the pile body. The charging pile also includes a power distribution controller. The power distribution controller communicates with multiple rectifier modules and the protocol conversion board of the first and second charging guns via a CAN bus. It is also electrically connected to the drive coils of AC contactors, busbar contactor groups, gun line output contactor groups, and parallel contactors via control lines. It is used to control the on / off state of each contactor according to the charging needs of the vehicle. Specifically, the physical structure of a dual-gun DC power supply mainly includes the pile body and integrated AC input unit, rectifier module group, DC output unit, parallel interface unit, and power distribution controller. The 380V three-phase AC power supply is first connected to the AC input unit. The core of this unit is a molded case circuit breaker with a rated current of 125A and a three-phase AC contactor. The molded case circuit breaker serves as the main switch and short-circuit protection element; its lower input terminal is connected to the power grid, and its upper output terminal is connected to the input terminal of the AC contactor. When the coil of the AC contactor is energized and engages... Three-phase AC power is delivered to the connecting copper busbar through its output terminal. The electrical energy is distributed to the rectifier module group via the copper busbar. In this embodiment, the rectifier module group consists of four independent duct rectifier modules with a rated power of 60kW connected in parallel. The AC input terminal of each rectifier module obtains three-phase AC power from the copper busbar through three wires (L1, L2, L3) and converts it into DC power efficiently. The DC output terminal of each rectifier module is connected to the high-voltage wall terminal of the DC output high-voltage box in the DC output unit through two positive wires and two negative wires. Inside the DC output high-voltage box, DC power from each rectifier module is collected onto the DC output copper busbar via internal wires. To achieve flexible power distribution, a busbar contactor group and a gun line output contactor group are installed on the DC output copper busbar. In this embodiment, the busbar contactor group includes three high-power DC contactors, which can be labeled KZ1-KZ4, KZ2-KZ5, and KZ3-KZ6. The on / off states of these contactors electrically divide the DC output copper busbar into four segments, thereby controlling whether the output of the four rectifier modules is independently output to different guns, or partially or fully output to different guns. The currents from the components are combined to form a larger power output source. The gun output contactor group includes a first gun output contactor group (including positive contactor 1K1 and negative contactor 1K2) that controls the on / off state of the first charging gun, and a second gun output contactor group (including positive contactor 2K1 and negative contactor 2K2) that controls the on / off state of the second charging gun. The power output from the module is combined, passes through the positive fuse, and is then closed by the corresponding gun output contactor to deliver electrical energy to the electric vehicle battery. Finally, it returns to the rectifier module through the negative shunt and contactor to form a complete charging circuit. To achieve parallel operation of multiple machines, this embodiment adds a parallel interface unit. The core of this unit is a set of parallel contactors, including a positive parallel contactor K9 and a negative parallel contactor K10. The input terminal of the positive parallel contactor K9 is led out from the copper busbar before the positive fuse of the first output contactor group 3. The input terminal of the negative parallel contactor K10 is led out from the copper busbar before the negative shunt of the second output contactor group. The output terminals of K9 and K10 are respectively led to the XT13-1 and XT13-3 terminals on the pile body for external parallel connection. In addition, reserved connection points XT13-2 and XT13-4 are respectively led out on the copper busbars before the positive fuse and negative shunt of the second gun output contactor group. When the two machines are interconnected, the XT13-1, XT13-2, XT13-3, and XT13-4 terminals of the first pile are connected to the corresponding XT13-2, XT13-1, XT13-4, and XT13-3 terminals of the second pile. At this time, the power of the two piles is connected end to end through the K9 and K10 contactors to form a "power ring", that is, a shared power pool. The power distribution controller (main control board ZK) is the brain of the entire system. Its power supply is provided by an auxiliary power source, which obtains single-phase AC power from the L1 and N bars of the molded case circuit breaker via a leakage current protector and converts it to 12V DC power. The power distribution controller's collaborative control functions are as follows: it communicates with the four rectifier modules via the CAN bus to obtain their operating status and maximum output capacity; simultaneously, it communicates with the protocol conversion boards of the first and second charging guns via the CAN bus to obtain the BMS charging demand parameters of the connected vehicle; and it directly controls the coils of the AC contactors, all contactors in the busbar contactor group, all contactors in the gun-line output contactor group, and the drive coils of the parallel contactors K9 and K10 through the control circuit. The program calculates the optimal power distribution scheme based on real-time vehicle demand and the status of each module, and physically implements the scheme by controlling the closing and opening of the contactors. For example, when only one vehicle is charging, the combiner contactor can be controlled to combine the power of all four modules to that vehicle. When multiple vehicles are connected in parallel, it can control the closing of K9 and K10 to feed the surplus power of this charging station into the power loop for use by vehicles at other charging stations, or extract power from the loop to meet the excess demand of vehicles at this charging station. The power distribution controller is also connected to the human-machine interface screen (for parameter setting and status display) and the card reader (for processing charging transactions) via RS232 communication lines. At the same time, the signals from components such as the emergency stop button and the light panel are also connected to the controller. To ensure reliable system operation, a branch protection circuit is also provided on the AC input side. This circuit is led out from the input terminal of the molded case circuit breaker, passes through a miniature circuit breaker in sequence, and is connected to the surge protector to discharge instantaneous current caused by grid impact and lightning strike. In addition, the cooling fans of the entire pile are controlled by the controller through intermediate relays to ensure effective heat dissipation in the independent air duct.

[0028] Reference Figures 1-3 The busbar contactor group includes multiple sets of DC output contactors, which are used to control the output of multiple rectifier modules to be combined on the DC output copper busbar. The gun line output contactor group includes a first gun output contactor group that controls the on / off state of the first charging gun, and a second gun output contactor group that controls the on / off state of the second charging gun. The rectifier module group consists of four 60kW independent duct rectifier modules connected in parallel, and its output terminal is connected to the high voltage wall terminal of the DC output high voltage box through positive and negative wires. Specifically, the rectifier module group is the core power source for this DC charging pile to achieve high power output. In this embodiment, four AC / DC rectifier modules with a rated power of 60kW are preferably used, working in parallel. This configuration of quantity and power level allows the theoretical maximum output power of a single pile to reach 240kW, which can meet the current mainstream electric vehicles' demand for high-power fast charging of 150kW and above when using a single gun. It also provides sufficient power redundancy for simultaneous fast charging with two guns. Each rectifier module is an independent and complete AC / DC conversion unit, which integrates PFC (Power Factor Correction) circuit and full-bridge LLC resonant converter. The core topology circuits, such as the rectifier, can efficiently convert the input 380V three-phase AC power into DC power with a voltage range of 200-750V or higher to adapt to electric vehicle batteries with different voltage platforms. The independent air duct design allows each rectifier module to have a physically isolated and dedicated heat dissipation air duct. Each air duct is equipped with an independent DC brushless cooling fan. During operation, cool air is drawn in from the independent air inlet on the side of the pile body, flows through the heat sink and power devices inside the module, and carries the heat directly to the outside of the pile body. This design avoids the "thermal short circuit" phenomenon of mutual interference of hot air flow between modules and heat accumulation in the traditional integrated air duct, and significantly improves the heat dissipation efficiency. In terms of electrical connections, the DC output terminal of each rectifier module is connected to the high-voltage wall-penetrating terminal of the DC output high-voltage box via two positive wires and two negative wires in a two-wire parallel connection. The purpose of the two-wire parallel connection is to carry the large current corresponding to the 60kW output of a single module, ensure that the temperature rise of the connection point is within a safe range, and improve the long-term electrical stability of the system. The high-voltage wall-penetrating terminal is made of high-performance insulating material, which not only enables reliable transmission of high voltage and high current, but also strictly isolates the high-voltage area inside the high-voltage box from the low-voltage area outside, ensuring the safety of operation and maintenance. In addition, all rectifier modules communicate with the power distribution controller in real time via the CAN bus. The controller sends output voltage and output current commands to each module through the bus, and collects the working status, operating parameters, fault codes and maximum output capacity of each module in real time. This communication and control mechanism is the basis for the power distribution controller to achieve precise and dynamic allocation of the entire "power pool".

[0029] Reference Figures 1-3 The busbar contactor group includes three sets of DC output contactors. The opening and closing of the DC output contactors are used to divide the DC output copper busbar into four sections and control whether the output of each rectifier module can be combined. Specifically, the busbar contactor group is a key actuator for realizing intelligent power distribution within a single pile and flexible output from multiple nozzles. Its core function is to physically reconstruct the connection mode of the DC busbar through different on / off combinations of the contactors, thereby achieving multiple working modes. The busbar contactor group consists of three sets of high-power DC contactors, each set containing one positive contactor and one negative contactor. For ease of description, they are labeled as the first set: positive contactor KZ1 and negative contactor KZ4, the second set: positive contactor KZ2 and negative contactor KZ, and the third set: positive contactor KZ3 and negative contactor KZ6. These contactors are directly installed on the DC output copper busbar inside the DC output high-voltage box. Their installation positions are carefully designed so that when all contactors are in the open state, the entire DC output copper busbar is divided into four mutually insulated copper busbar segments. Each copper busbar segment is connected to the output of a rectifier module. The power distribution controller can realize multiple power distribution modes by controlling the coordinated action of these three sets of contactors.

[0030] Reference Figures 1-3 The parallel interface unit includes a set of parallel contactors, including a positive parallel contactor and a negative parallel contactor, and external parallel connection terminals include a first reserved connection point, a second reserved connection point, a third reserved connection point and a fourth reserved connection point.

[0031] Specifically, the positive parallel contactor K9 has its input terminal precisely connected to the positive DC bus between the busbar contactor group and the first gun output contactor group (1K1), specifically on the copper busbar before the positive fuse of the first gun. Its output terminal is connected to the XT13-1 terminal of the external parallel connection terminal. The negative parallel contactor K10 has its input terminal precisely connected to the negative DC bus between the busbar contactor group and the second gun output contactor group (2K2), specifically on the copper busbar before the negative shunt of the second gun. Its output terminal is connected to the XT13-3 terminal of the external parallel connection terminal. When K9 and K10 are open, this charging station is an independent charging system. When they are closed, the DC bus of this charging station is connected to other charging stations through the XT13 terminal, and power can flow in or out. The four reserved connection points constitute a standardized parallel physical interface, defined as follows: XT13-1 is defined as the positive power output / input point of this pile, which is directly connected to the output terminal of K9 internally; XT13-2 is defined as the external positive power input / output point, which is directly led out from the positive bus between the second gun output contactor group (2K1) and the bus contactor group (KZ3) and is located before its positive fuse; XT13-3 is defined as the negative power output / input point of this pile, which is directly connected to the output terminal of K10 internally; and XT13-4 is defined as the external negative power input / output point. This terminal is directly led out from the negative busbar between the second gun output contactor group (2K2) and the busbar contactor group (KZ6), and is located before its negative shunt. When the two machines are interconnected, connect the XT13-1 terminal of the first pile to the XT13-2 terminal of the second pile, connect the XT13-2 terminal of the first pile to the XT13-1 terminal of the second pile, connect the XT13-3 terminal of the first pile to the XT13-4 terminal of the second pile, and connect the XT13-4 terminal of the first pile to the XT13-3 terminal of the second pile. At this time, the DC busbars of the two piles form a closed loop through contactors K9 and K10 and external cables. The combined ring DC bus, or power ring, allows the rectifier modules of two charging piles to jointly inject power into this ring network, forming a shared power pool. The power distribution controllers of each pile communicate through an interconnected CAN bus to coordinate the control of the K9, K10 contactors and other internal contactors of the pile. This enables intelligent scheduling and bidirectional flow of power within the ring network. For example, when the load of pile A is low, its surplus power can flow out through K9 and be transmitted to pile B with a higher load via cable. This parallel interface unit design allows charging station operators to smoothly increase the total charging power without large-scale modifications to the existing power grid, simply by adding charging piles and connecting cables.

[0032] Reference Figures 1-3The input terminal of the positive parallel contactor is led out from before the positive fuse of the first gun output contactor group, and the output terminal is connected to the first reserved connection point. The input terminal of the negative parallel contactor is led out from before the negative shunt of the second gun output contactor group, and the output terminal is connected to the third reserved connection point.

[0033] Specifically, the connection strategy of the positive parallel contactor K9 is as follows: the input terminal of K9 is not arbitrarily connected to any position on the positive busbar, but is specifically led out from the copper busbar behind the positive contactor 1K1 of the first gun output contactor group, but before its positive fuse FU1. This connection point is located after the gun output contactor 1K1, ensuring that the opening and closing of K9 is not affected by the state of 1K1. Even if the first gun is not charged and 1K1 is open, as long as the system allows, K9 can still close, bringing the positive power of this pile into the parallel network for use by other piles. The connection point is located before the positive fuse FU1, which makes the power path led out by K9 protected by the total output fuse of this pile. When extreme faults such as short circuits occur in the positive line of the parallel network, the fuse of this pile can quickly cut off the fault current, prevent the accident from escalating, and ensure the safety of the equipment of this pile. At the same time, it also avoids the internal protection devices of this pile from malfunctioning due to external faults. The connection strategy for the negative parallel contactor K10 is as follows: the input terminal of K10 is specifically led out from the rear end of the negative contactor 2K2 of the second-pole output contactor group, but before its negative shunt SH2, on the copper busbar. Similar to K9, this connection point ensures the independent operation of K10, unaffected by the on / off state of the second-pole charging state 2K2. The shunt is a sensor used to accurately measure the charging current. Placing the input terminal of K10 before the shunt ensures that all current flowing through or into K10 is detected and measured by the shunt of this pile. This guarantees that the power distribution controller can obtain accurate total output / input current data, including inter-pile power exchange, for... The precise control of the algorithm provides a real basis. If connected after the shunt, the current of mutual assistance between piles cannot be monitored, leading to inaccurate control. K9 and K10, as a pair, jointly control the connection between this pile and the external parallel network. Their on / off state is decided uniformly by the power distribution controller. Specifically, when the controller determines that this pile has surplus power available for output, it will close K9 and K10 to push the power to the parallel network. When the controller determines that this pile needs to obtain additional power from the outside, it will also close K9 and K10 to draw power from the parallel network. When this pile operates independently or the parallel network does not require power interaction, K9 and K10 will be disconnected, allowing this pile to operate as an independent system.

[0034] Reference Figures 1-3The second reserved wiring point is led out from the copper busbar between the positive contactor of the second gun output contactor group and the corresponding positive contactor in the busbar contactor group. The fourth reserved wiring point is led out from the copper busbar between the negative contactor of the second gun output contactor group and the corresponding negative contactor in the busbar contactor group.

[0035] Specifically, XT13-2 and XT13-4, as two other key terminals for external parallel connection, work in conjunction with the aforementioned XT13-1 and XT13-3 to form a complete circuit for bidirectional power flow. Terminal XT13-2 is electrically and precisely connected to the positive copper busbar between the input terminal of the positive contactor 2K1 in the second gun output contactor group and the output terminal of the positive contactor KZ3 in the busbar contactor group, which is responsible for upstream busing. This connection point is also located before the positive fuse FU2 in the second gun. As an input point, when power from other piles is transmitted to XT13-2 of this pile via cables, the power can be directly supplied to the second charging gun via the 2K1 contactor (if it is closed), or injected in reverse into the DC bus of this pile via the KZ3 contactor (if it is closed), thereby supplying the first charging gun or supplementing the power of the rectifier module of this pile. This design allows the externally input power to have the highest scheduling flexibility within this pile. As an output point, when this pile needs to output power, this point can also serve as one of the power outflow paths. Terminal XT13-4 is electrically and precisely connected to the negative copper busbar between the input terminal of the negative contactor 2K2 in the second gun output contactor group and the output terminal of the corresponding negative contactor KZ6 in the busbar contactor group. This connection point is also located before the negative shunt SH2 in the second gun. Current measurement is consistent with the design principle of K10. Placing XT13-4 before shunt SH2 ensures that all positive current flowing into or out of XT13-2, and its corresponding return current, can be accurately measured by the same shunt SH2, maintaining the integrity of the system's total current monitoring. At the same time, it provides a corresponding, monitored negative return path for the positive current flowing into XT13-2, forming a complete negative current channel together with XT13-3.

[0036] Reference Figures 1-3 The AC input unit also includes a first branch circuit and a second branch circuit. The first branch circuit is connected in sequence to a miniature circuit breaker and a surge protector, and is led out from the input terminal of the molded case circuit breaker to protect against grid impact and lightning instantaneous current. The second branch circuit is led out from the input terminal of the molded case circuit breaker and is connected in sequence to a residual current device and an auxiliary power supply. The auxiliary power supply is an AC / DC switching power supply module, which is used to convert single-phase AC power into DC power to supply power to the power distribution controller and the pile control system.

[0037] Specifically, the first branch circuit, as a parallel branch of the main power circuit, is directly led out from the input terminal of the molded case circuit breaker on the grid side. Thus, even if the molded case circuit breaker is disconnected due to fault or maintenance, this protection circuit can still be directly connected to the grid to provide uninterrupted protection. In the circuit, the live wires (L1, L2, L3) and the neutral wire (N) are first connected to a three-phase miniature circuit breaker. The main function of this miniature circuit breaker is not to interrupt the large current of the main circuit, but to serve as a backup protection device when the surge protector itself is in operation. It can promptly disconnect the faulty surge protector from the grid to prevent the accident from escalating. After passing through the miniature circuit breaker, the line is immediately connected to the surge protector. The surge protector usually uses nonlinear components such as varistors (MOV) or gas discharge tubes. When a momentary overvoltage occurs on the line due to lightning strike or the start-up and shutdown of large equipment, the surge protector will instantly reduce its impedance to an extremely low level, quickly discharging the huge surge current to the ground (PE line), thereby clamping the voltage on the line within a safe range and protecting expensive equipment such as downstream rectifier modules from impact. The second branch circuit provides an independent, protected AC power supply to the control system. It draws a single live wire (L1) and a neutral wire (N) from the input of the molded case circuit breaker. The circuit first passes through a double-pole residual current device (RCD), which monitors leakage current in the power supply circuit. If leakage occurs in the auxiliary power supply or subsequent control circuit due to insulation damage or other reasons, and the leakage current exceeds a set threshold, the power supply can be quickly cut off to prevent electric shock. After passing through the RCD, the single-phase AC power is sent to the input of the auxiliary power supply, which is an AC / DC switching power supply module. Its function is to convert the input 220V single-phase AC power... It converts and provides multiple stable, isolated low-voltage DC power supplies, with a typical output of +12V / several A, used to power all low-voltage electrical units such as power distribution controllers, relay / contactor coils, cooling fans, indicator boards, etc. +5V or +3.3V may power the controller core board or other logic circuits. The second branch circuit provides the premise for the normal operation of the power distribution controller, ensuring that even when the main power circuit is not working (such as when no vehicle is charging), the control system can still standby, communicate, display, and respond to start commands. The introduction of the leakage current protector adds crucial safety protection to this constant power supply circuit.

[0038] Reference Figures 1-3 The power distribution controller is also connected to the human-machine interface screen via an RS232 communication line for parameter setting and status display, and is connected to a card reader via another independent RS232 communication line for processing charging transactions.

[0039] Specifically, the human-machine interface screen is typically a high-brightness, wide-viewing-angle LCD touchscreen, installed in a prominent position on the front door of the pile for easy observation and operation by users. It is connected to the power distribution controller via an independent RS232 serial communication line. The RS232 protocol is widely used in the field of industrial human-machine interfaces due to its simple structure, strong anti-interference ability, and reliable transmission. To ensure the stability of long-distance transmission, an RS232 to RS485 signal conversion module can be built into or connected to the controller and screen. The power distribution controller acts as the host and is responsible for sending the dynamic data to be displayed to the screen, including but not limited to grid voltage, output current / voltage, charged amount, charging time, real-time power, status of each rectifier module, network connection status, fault alarm information, etc. At the same time, the controller receives user commands triggered by screen touch events, such as starting charging, stopping charging, selecting charging mode, switching system language, querying historical records, and configuring parameters in operator mode. The card reader is typically a card reader module that supports IC cards or RFID cards. It is also installed at the front door of the charging station for convenient card swiping by users. It is connected to the power distribution controller via a separate RS232 communication line. This physical channel isolation avoids mutual interference with the screen communication, improving the security and reliability of transaction data. In idle state, the screen prompts the user to swipe their card. When the user brings a valid charging card close to or inserts it into the card reader, the card reader reads the information on the card and transmits it to the power distribution controller via the RS232 line. The controller verifies the card information to confirm its validity and whether the balance is sufficient. After successful verification, the controller prompts the user to proceed with the next operation on the screen. Only after the user confirms the start, the controller controls the corresponding contactor to close, starting the charging process and simultaneously initiating the internal billing program to deduct the fee from the card balance in real time. When charging is finished, the controller controls the contactor to open, stopping billing, and displays detailed information about the charging (such as the amount consumed and the final balance) on the screen, completing a full transaction loop.

[0040] Working principle: The system uses a power distribution controller as its intelligent core. First, the three-phase AC power is converted into DC power by the rectifier module group. Then, through the dynamic network composed of the bus contactor group in the pile, a shared power pool inside the single pile is formed on the DC bus. The controller obtains the charging requirements and module status of the vehicle's BMS in real time via the CAN bus, dynamically controls the busbar and gun output contactors, and accurately distributes the power in the power pool to the two guns. Through the parallel contactors (K9, K10) and standardized terminals (XT13-1 to XT13-4) in the parallel interface unit, the DC buses of multiple charging piles are cross-connected to form a cross-pile power ring network. Finally, the controllers of each charging pile make collaborative decisions through the interconnected CAN bus to achieve real-time scheduling and sharing of power on a global scale, thereby maximizing the overall charging efficiency and resource utilization.

[0041] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A star-chain type dual-gun DC charging station capable of charging multiple units in parallel, comprising a station body, an AC input unit, a rectifier module group, a DC output unit, a first charging gun and a second charging gun, characterized in that: The AC input unit includes a molded case circuit breaker and an AC contactor connected in sequence, used to connect to and control a three-phase AC power supply. The rectifier module group consists of four independent rectifier modules connected in parallel. Its input terminal is connected to three-phase AC power through the AC contactor, and its output terminal is connected to the DC output unit. The DC output unit includes a DC output high voltage box, a DC output copper busbar disposed inside the high voltage box, and a busbar contactor group and a gun line output contactor group disposed on the DC output copper busbar. The DC pile is also equipped with a parallel interface unit, which includes a set of parallel contactors. The input end of the parallel contactor is connected to the DC bus between the bus contactor group and the gun line output contactor group, and its output end is led to the external parallel connection terminal on the pile body. The charging pile also includes a power distribution controller, which is connected to the protocol conversion board of multiple rectifier modules and the first and second charging guns via a CAN bus, and is electrically connected to the drive coils of the AC contactor, the bus contactor group, the gun line output contactor group and the parallel contactor via control lines, for controlling the on and off of each contactor according to the charging needs of the vehicle.

2. The star-chain type dual-gun DC charging pile with multiple units in parallel as described in claim 1, characterized in that: The busbar contactor group includes multiple sets of DC output contactors for controlling the outputs of the multiple rectifier modules to be combined on the DC output copper busbar. The gun line output contactor group includes a first gun output contactor group for controlling the on / off state of the first charging gun and a second gun output contactor group for controlling the on / off state of the second charging gun. The rectifier module group consists of four 60kW independent duct rectifier modules connected in parallel, and its output terminal is connected to the high-voltage wall terminal of the DC output high voltage box through positive and negative wires.

3. The star-chain type dual-gun DC charging pile with multiple units in parallel as described in claim 1, characterized in that: The busbar contactor group includes three sets of DC output contactors. The switching on and off of the DC output contactors is used to divide the DC output copper busbar into four segments and control whether the output of each rectifier module can be combined.

4. The star-chain type dual-gun DC charging pile with multiple units in parallel as described in claim 2, characterized in that: The parallel interface unit includes a set of parallel contactors, namely a positive parallel contactor and a negative parallel contactor, and the external parallel connection terminals include a first reserved connection point, a second reserved connection point, a third reserved connection point and a fourth reserved connection point.

5. A star-chain type dual-gun DC charging pile with multiple units in parallel as described in claim 4, characterized in that: The input terminal of the positive parallel contactor is led out from before the positive fuse of the first gun output contactor group, and the output terminal is connected to the first reserved wiring point. The input terminal of the negative parallel contactor is led out from before the negative shunt of the second gun output contactor group, and the output terminal is connected to the third reserved wiring point.

6. A star-chain type dual-gun DC charging pile with multiple units in parallel as described in claim 4, characterized in that: The second reserved wiring point is led out from the copper busbar between the positive contactor of the second gun output contactor group and the corresponding positive contactor in the busbar contactor group, and the fourth reserved wiring point is led out from the copper busbar between the negative contactor of the second gun output contactor group and the corresponding negative contactor in the busbar contactor group.

7. A star-chain type dual-gun DC charging pile with multiple units in parallel as described in claim 1, characterized in that: The AC input unit also includes a first branch circuit and a second branch circuit. The first branch circuit is connected in sequence to a miniature circuit breaker and a surge protector, and is led out from the input terminal of the molded case circuit breaker to protect against grid impact and lightning instantaneous current. The second branch circuit is led out from the input terminal of the molded case circuit breaker and is connected in sequence to a residual current device and an auxiliary power supply. The auxiliary power supply is an AC / DC switching power supply module, which is used to convert single-phase AC power into DC power to supply power to the power distribution controller and the pile control system.

8. A star-chain type dual-gun DC charging pile with multiple units in parallel as described in claim 1, characterized in that: The power distribution controller is also connected to a human-machine interface screen via an RS232 communication line for parameter setting and status display, and is connected to a card reader via another independent RS232 communication line for processing charging transactions.

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