V2g bi-directional charging and discharging pile and charging and discharging control method, device and system thereof

Abstract

The application discloses a V2G bidirectional charge-discharge pile and a charge-discharge control method, device and system thereof, and relates to the technical field of electric vehicle charging. The method comprises the following steps: in the charging mode, a power module is controlled to convert alternating current from a power grid into direct current to charge a battery of a vehicle, and zero sequence circulating current compensation is performed during the charging process. The zero sequence circulating current compensation comprises the following steps: based on a circulating current error of a total zero sequence circulating current value of each AC / DC bidirectional converter and a target circulating current value, a compensation voltage allocated to each AC / DC bidirectional converter is adjusted to offset a voltage difference between each AC / DC bidirectional converter, which generates a zero sequence circulating current. By introducing the circulating current error based on the total zero sequence circulating current value and the target circulating current value to adjust the compensation voltage, the application can actively offset the voltage difference between each AC / DC bidirectional converter, which generates a zero sequence circulating current, and effectively suppress the zero sequence circulating current.

Description

Technical Field

[0001] This application relates to the field of electric vehicle charging technology, specifically to a V2G bidirectional charging and discharging pile and its charging and discharging control method, device and system. Background Technology

[0002] With the continuous increase in the number of various new energy vehicles (ordinary cars, mining vehicles, engineering vehicles, etc.), the demand for charging piles, as a key supporting facility, is becoming increasingly urgent. However, traditional charging piles have a single function, only providing basic charging services, which is insufficient to meet the requirements of modern charging networks for intelligence, high power, and bidirectional energy interaction. Accordingly, high-power DC fast charging and V2G (Vehicle-to-Grid) technology have been applied to charging piles, and they have two core development directions in the industry: on the one hand, the battery capacity of electric vehicles is constantly increasing, which puts forward higher requirements for charging power and speed; on the other hand, V2G technology enables electric vehicles to participate in grid peak shaving and frequency regulation as distributed energy storage units, realizing bidirectional energy interaction between vehicles and the grid.

[0003] The core task of V2G bidirectional charging and discharging piles based on high-power DC fast charging and V2G technology includes converting AC power from the power grid into DC power that can be directly used by electric vehicles and controlling the charging process. This is mainly achieved by multiple power modules responsible for converting AC power to DC power and regulating the voltage / current.

[0004] However, in high-power charging scenarios, a zero-sequence circulating current problem exists when multiple power modules operate in parallel. Specifically, the zero-sequence circulating current is caused by the asymmetry (including a zero-sequence component) in the output voltage of multiple parallel power modules. For example, power module A outputs 310V and module B outputs 309V. Due to the voltage difference, an additional circulating current will be generated between them. This current is called the zero-sequence circulating current. It does not pass through the charging gun but only flows between the modules, causing the modules to heat up and reduce efficiency.

[0005] Zero-sequence circulating current is one of the key technical bottlenecks of V2G bidirectional charging and discharging piles, which seriously affects their performance and charging efficiency. Moreover, unlike the zero-sequence circulating current involved in ordinary power grids, the zero-sequence circulating current involved in V2G bidirectional charging and discharging piles is prone to changes in phase and amplitude due to the presence of bidirectional power flow, posing a greater challenge to zero-sequence circulating current suppression and control. Summary of the Invention

[0006] The purpose of this application is to provide a V2G bidirectional charging and discharging pile and its charging and discharging control method, device and system, so as to at least partially solve the above-mentioned technical problems.

[0007] To achieve the above objectives, the first aspect of this application provides a charging and discharging control method for a V2G bidirectional charging and discharging pile. The V2G bidirectional charging and discharging pile is configured with multiple power modules connected in parallel and a main control module for performing power control. The multiple power modules include at least an AC / DC bidirectional converter with a three-phase Vienna PFC topology and a DC / DC bidirectional converter with a DAB-ISOP topology. The charging and discharging control method is executed by the main control module and includes: in charging mode, controlling the power module to convert AC power from the grid into DC power to charge the vehicle's battery, and performing zero-sequence circulating current compensation during the charging process, wherein the zero-sequence circulating current compensation includes: adjusting the compensation voltage allocated to each AC / DC bidirectional converter in the zero-sequence circulating current path based on the circulating current error between the total zero-sequence circulating current value of the zero-sequence circulating current path formed by multiple AC / DC bidirectional converters connected in parallel, so as to offset the voltage difference between the zero-sequence circulating current generated between the AC / DC bidirectional converters, wherein the total zero-sequence circulating current value of the zero-sequence circulating current path is the sum of the measured zero-sequence currents of each AC / DC bidirectional converter in the zero-sequence circulating current path; and in discharging mode, controlling the power module to invert the DC power from the vehicle's battery into AC power to feed into the grid.

[0008] Through the above technical solution, the embodiments of this application introduce a circulating current error based on the total zero-sequence circulating current value and the target circulating current value to adjust the compensation voltage, which can actively offset the voltage difference of zero-sequence circulating current generated between each AC / DC bidirectional converter, effectively suppress the zero-sequence circulating current formed by the neutral point connection of the three-phase Vienna PFC topology, improve the current sharing characteristics of parallel modules, reduce circulating current loss and heat generation, and support smooth switching of V2G bidirectional charging and discharging modes.

[0009] In this embodiment, adjusting the compensation voltage allocated to each AC / DC bidirectional converter in the zero-sequence circulating current path includes: inputting the circulating current error to a preset linear controller to output a total compensation voltage value to offset the voltage difference; and allocating the total compensation voltage value to each AC / DC bidirectional converter according to the real-time operating conditions of each AC / DC bidirectional converter to obtain a corresponding compensation voltage, wherein the compensation voltage is mapped to the duty cycle correction amount of the corresponding AC / DC bidirectional converter to adjust the PWM signal used to drive the switching transistor of the AC / DC bidirectional converter.

[0010] Through this preferred technical solution, the embodiments of this application calculate the total compensation voltage value by a preset linear controller (such as a PR or PI controller), allocate the compensation voltage according to the real-time operating conditions of each AC / DC bidirectional converter, and then map the compensation voltage to the duty cycle correction amount to adjust the PWM signal, thereby realizing refined and dynamic compensation for zero-sequence circulating current and improving the adaptability and engineering feasibility of compensation.

[0011] In this embodiment of the application, the method further includes performing current sharing control during the charging process. The current sharing control includes: correcting the output current of the corresponding power module based on the current error between the real-time output current of each power module and the average output current of all power modules.

[0012] Through this preferred technical solution, the embodiments of this application correct the module output current based on the error between the real-time output current and the average output current of each power module, thereby achieving current sharing control when multiple modules are connected in parallel. This avoids the problem of some modules being overloaded while others are lightly loaded, and improves the system power utilization, reliability, and stability in high-power charging scenarios.

[0013] In this embodiment, the method further includes switching between trickle charging, constant current charging, and constant voltage charging during the charging process based on the vehicle's battery voltage. The switching includes: performing trickle charging when the battery voltage is less than a set low-voltage threshold; performing constant current charging when the battery voltage is greater than or equal to the low-voltage threshold and less than a set constant-voltage threshold; and performing constant voltage charging when the battery voltage is equal to or greater than the constant-voltage threshold, and stopping charging if the battery voltage is greater than the constant-voltage threshold for more than a preset safety time or the voltage difference between the two exceeds a preset safety tolerance range. During the switch from constant current charging to constant voltage charging, the final current value of the constant current charging stage is used as the starting reference current of the constant-voltage charging stage.

[0014] Through this preferred technical solution, the embodiments of this application automatically switch between three stages of trickle charging, constant current charging, and constant voltage charging based on the battery voltage. When switching from constant current to constant voltage, the final current value is used as the starting reference current for the constant voltage stage, which realizes a smooth transition of the three-stage charging, avoids the current / voltage jump at the moment of switching, and helps to extend battery life and improve charging safety.

[0015] A second aspect of this application provides a control device, comprising: a memory configured to store instructions; and a processor configured to retrieve the instructions from the memory and, when executing the instructions, to implement any of the above-described charge / discharge control methods.

[0016] Through this technical solution, the embodiments of this application provide a control device with a memory and processor storing instructions, which can execute the above-mentioned charging and discharging control method, and provide a programmable and integrable hardware platform foundation for realizing zero-sequence circulating current compensation, current sharing control, three-stage charging and V2G bidirectional control.

[0017] In this embodiment of the application, the control device is an STM32F103RCT6 microcontroller capable of running the FreeRTOS real-time operating system.

[0018] Through this preferred technical solution, the embodiment of this application uses an STM32F103RCT6 microcontroller capable of running the FreeRTOS real-time operating system as the control device. It utilizes a preemptive task scheduling architecture to achieve multi-task parallel processing, ensuring that the protection logic response time is ≤10ms. Furthermore, it leverages its rich peripheral interfaces (CAN, RS485, SPI, ADC, etc.) to meet the high real-time communication and control requirements of the charging pile with the vehicle BMS, power module, energy meter, display screen, etc.

[0019] A third aspect of this application provides a V2G bidirectional charging and discharging station, comprising: a plurality of power modules connected in parallel, wherein the plurality of power modules include a DC / DC bidirectional converter employing a DAB-ISOP topology and an AC / DC bidirectional converter employing a three-phase Vienna PFC topology, wherein the DC / DC bidirectional converter and the AC / DC bidirectional converter employ silicon carbide MOSFET power devices; and a main control module for performing power control, wherein the main control module is configured to integrate any of the above-mentioned control devices.

[0020] Through this technical solution, the embodiments of this application achieve high efficiency (AC / DC charging mode ≥95.5%), high power density, and wide voltage range (supporting 200-1000Vdc) bidirectional charging and discharging functions by cascading a three-phase Vienna PFC topology AC / DC bidirectional converter with a DAB-ISOP topology and cooperating with silicon carbide MOSFET power devices. The parallel power module design provides redundancy, fault tolerance, and flexible expansion capability, and the integrated control device of the main control module enables the engineering implementation of zero-sequence circulating current compensation and current sharing control.

[0021] In this embodiment, the V2G bidirectional charging and discharging pile further includes: a communication module configured with multiple interface circuits and a wireless communication unit, the multiple interface circuits including a CAN interface circuit, an RS485 interface circuit, an Ethernet interface circuit, and a display interface circuit; a human-machine interaction module configured to realize human-machine interaction; an energy metering module configured to perform energy detection on the V2G bidirectional charging and discharging pile and provide energy detection results to the main control module; and a safety protection module configured with an overcurrent protection unit, an overvoltage / undervoltage protection unit, an overtemperature protection unit, an insulation monitoring unit, a reverse connection protection unit, an anti-islanding protection unit, and / or an emergency stop switch.

[0022] Through this preferred technical solution, the embodiments of this application integrate a communication module (CAN, RS485, Ethernet, wireless), a human-machine interaction module, an energy metering module, and multiple safety protection modules (overcurrent, overvoltage / undervoltage, overtemperature, insulation monitoring, reverse connection protection, anti-islanding protection, emergency stop switch), constructing a complete V2G bidirectional charging and discharging pile functional system, realizing interconnection and interoperability with vehicle BMS, power grid EMS, and cloud platform, and providing multi-level, hardware and software collaborative safety assurance.

[0023] A fourth aspect of this application provides a control system based on V2G bidirectional charging and discharging piles, comprising: any of the aforementioned V2G bidirectional charging and discharging piles; and a cloud platform, a vehicle BMS, and a power grid EMS communicating with the V2G bidirectional charging and discharging piles. The communication protocol stack between the V2G bidirectional charging and discharging piles and the vehicle BMS includes the GB / T 27930 protocol, the ISO 15118-20 V2G protocol, and the J1939 protocol stack, and the V2G bidirectional charging and discharging piles communicate bidirectionally with the cloud platform via the OCPP 2.0.1 protocol.

[0024] Through this technical solution, the embodiments of this application construct a complete control system including V2G bidirectional charging and discharging piles, a cloud platform, a vehicle BMS, and a power grid EMS. It adopts GB / T 27930, ISO 15118-20 V2G protocols and J1939 protocol stacks to communicate with the vehicle BMS, and adopts OCPP 2.0.1 protocol to communicate with the cloud platform, achieving full-stack communication protocol compatibility. This ensures the interconnection and interoperability between charging piles and different brand vehicle models and different operator platforms, and provides standardized support for V2G scheduling, remote monitoring, and protocol expansion.

[0025] In this embodiment of the application, the vehicle is a mining vehicle.

[0026] Through this preferred technical solution, the embodiments of this application apply the above-mentioned control system to mining vehicles, which can realize a number of mining area-specific functions, transforming mining vehicles from "energy-consuming equipment" into "mobile energy storage units", supporting peak shaving and valley filling, frequency regulation, etc. of the mining area microgrid, and significantly improving the economic efficiency of mine electricity use, power supply reliability and mining machine uptime efficiency.

[0027] Other features and advantages of the embodiments of this application will be described in detail in the following detailed description section. Attached Figure Description

[0028] The accompanying drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the following detailed description to explain the embodiments of this application, but do not constitute a limitation on the embodiments of this application. In the drawings: Figure 1The schematic diagram illustrates a flow chart of a charging and discharging control method for a V2G bidirectional charging and discharging pile according to an embodiment of this application; Figure 2 A schematic diagram illustrating the flow sharing control according to an embodiment of this application is shown. Figure 3 This schematic diagram illustrates a structural block diagram of a control device according to an embodiment of the present application; Figure 4 This illustration schematically shows a functional structure diagram of a V2G bidirectional charging and discharging pile according to an embodiment of this application; Figure 5 The schematic diagram illustrates the functional structure of a control system for a V2G-based bidirectional charging and discharging pile according to an embodiment of this application; Figure 6 The schematic diagram illustrates the structure of a control system based on a hierarchical modular design according to an embodiment of this application; and Figure 7 The illustration shows a schematic diagram of the process for high-power intelligent DC fast charging and V2G bidirectional charging and discharging control of mining vehicles according to an embodiment of this application. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for illustration and explanation of the embodiments of this application and are not intended to limit the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0030] It should be noted that the acquisition, transmission, storage, use, and processing of data in the technical solution of this application all comply with relevant laws and regulations. In the embodiments of this application, certain existing industry solutions such as software, components, and models may be mentioned. These should be considered exemplary, intended only to illustrate the feasibility of implementing the technical solution of this application, and do not imply that the applicant has already used or necessarily used such solutions.

[0031] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0032] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0033] Before introducing the embodiments of this application, some of the terms involved will be introduced here so that those skilled in the art can more clearly understand the embodiments of this application.

[0034] 1. Three-phase Vienna PFC (Power Factor Correction) topology: This is essentially a unidirectional three-level boost rectifier, specifically designed to convert three-phase AC to DC. While converting current, the three-phase Vienna PFC topology achieves: an input current close to a sine wave; a power factor close to 1 (typically >0.99); and extremely low total harmonic distortion (THD) (typically <5%). The three-phase Vienna PFC topology features high efficiency, low component stress, no bridge arm shoot-through risk, and unidirectional transmission, making it suitable for high-power DC fast charging.

[0035] In the AC / DC converter based on a three-phase Vienna PFC in this embodiment, the midpoint of the DC bus capacitor is directly connected to the neutral line (N line) of the power grid. This topology allows the zero-sequence component of the three-phase input current to form a closed loop through the filter inductor, power switch, and the midpoint of the bus capacitor, thereby creating a zero-sequence circulating current path within the system. This circulating current does not participate in forward power transfer but leads to uneven current distribution between power modules, increases additional losses, and causes module heating and decreased efficiency.

[0036] 2. DAB (Dual Active Bridge) - ISOP (Input-Series Output-Parallel) topology, also known as DAB-ISOP topology. The DAB-ISOP topology is a combined structure of a bidirectional isolated DC / DC converter used to achieve bidirectional energy transfer between the high-voltage and low-voltage sides, while meeting the requirements of high-voltage input and high-current output through modular combination. DAB has the following advantages: 1) Inherently supports bidirectional power transfer; 2) Enables zero-voltage switching (ZVS) with low switching losses; 3) Symmetrical structure and relatively simple control.

[0037] 3. Zero-sequence circulation mathematical model.

[0038] This application establishes a mathematical model for the zero-sequence circulating current of multiple AC / DC bidirectional converters connected in parallel. This zero-sequence circulating current mathematical model describes that the total zero-sequence circulating current value of the zero-sequence circulating current path formed by multiple AC / DC bidirectional converters connected in parallel is the sum of the measured zero-sequence currents of each AC / DC bidirectional converter in the zero-sequence circulating current path. Thus, the main control module first reads the AC-side three-phase current sampling values ​​from each AC / DC bidirectional converter via the CAN bus, for example, denoted as (i... ai i bi i ci Then, calculate the measured zero-sequence current i for each converter. 0i = (i ai + i bi +i ci ) / 3, and finally calculate the total zero-sequence circulation value i cir = Σ(i 0i ).

[0039] 4. Current sharing control: This refers to ensuring that each power module connected in parallel bears the same output current (or is distributed proportionally), thereby avoiding overload of individual modules and idleness of other modules.

[0040] Figure 1 The schematic diagram illustrates a flow chart of a charging and discharging control method for a V2G bidirectional charging and discharging pile according to an embodiment of this application. The V2G bidirectional charging and discharging pile is configured with multiple power modules connected in parallel and a main control module for performing power control. The multiple power modules include at least an AC / DC bidirectional converter using a three-phase Vienna PFC topology. The charging and discharging control method is executed by the main control module.

[0041] like Figure 1 As shown, the charge and discharge control method of this application embodiment may include the following steps S100 and S200.

[0042] Step S100: In charging mode, the power module is controlled to convert AC power from the grid into DC power to charge the vehicle's battery. Zero-sequence circulating current compensation is performed during the charging process. This zero-sequence circulating current compensation includes adjusting the compensation voltage allocated to each AC / DC bidirectional converter in the zero-sequence circulating current path based on the circulating current error between the total zero-sequence circulating current value and the target circulating current value, to offset the voltage difference that generates zero-sequence circulating current between the individual AC / DC bidirectional converters. As mentioned above, the total zero-sequence circulating current value of the zero-sequence circulating current path is the sum of the measured zero-sequence currents of each AC / DC bidirectional converter in the zero-sequence circulating current path.

[0043] In a preferred embodiment, adjusting the compensation voltage allocated to each AC / DC bidirectional converter in the zero-sequence circulating current path includes: inputting the circulating current error to a preset linear controller to output a total compensation voltage value for offsetting the voltage difference; and allocating the total compensation voltage value to each AC / DC bidirectional converter according to the real-time operating conditions of each AC / DC bidirectional converter to obtain a corresponding compensation voltage, which is mapped to the duty cycle correction amount of the corresponding AC / DC bidirectional converter to adjust the PWM signal used to drive the switching transistor of the AC / DC bidirectional converter.

[0044] The preset linear controller is either a PR (Proportional-Resonant) controller or a PI (Proportional-Integral) controller.

[0045] For this preferred embodiment, for example, the target circulating current value is 0, and the total zero-sequence circulating current value i is obtained as described above. cir Next, the circulation error Δi is further calculated. cir = 0 - i cir The circulation error Δi cirThe input quasi-PR controller calculates the total compensation voltage value V_comp based on preset control coefficients (Kp, Kr_1, Kr_3), where Kp, Kr_1, and Kr_3 are the proportional coefficient, fundamental resonant coefficient, and third harmonic resonant coefficient of the PR controller, respectively. Based on the real-time operating conditions (such as output power and temperature) of each AC / DC bidirectional converter (hereinafter referred to as a module), the total compensation voltage value V_comp is allocated to each module. For the i-th module, its allocated compensation voltage is ΔV_i = α_i * V_comp, where α_i is the allocation coefficient (equal by default for all modules, adjustable to 0 in case of an anomaly). The compensation voltage ΔV_i is mapped to a duty cycle correction: ΔD_i = ΔV_i / V_bus (V_bus is the DC bus voltage). ΔD_i is then superimposed on the duty cycle command Di_i_old of the original SVPWM modulation wave for the module: Di_i_new = Di_i_old + ΔD_i. The corrected PWM signal D_i_new drives the switching transistors of the power module (e.g., silicon carbide MOSFETs), directly changing the voltage output of each module and actively canceling the voltage difference that generates zero-sequence circulating current.

[0046] In another preferred embodiment, for the charging mode, current sharing control is further performed during the charging process, wherein the current sharing control includes: correcting the output current of the corresponding power module based on the current error between the real-time output current of each power module and the average output current of all power modules.

[0047] For example, such as Figure 2 As shown, flow sharing control may include the following steps S110-S160.

[0048] Step S110, Current Acquisition: The main control module acquires the output current (I1, I2, … In) of each module in real time through the current sensors inside each power module.

[0049] Step S120, Average current calculation: The main control module calculates the average current I_avg = (I1+I2+…+In) / n.

[0050] Step S130, Error Calculation: For the i-th power module, calculate its current error ΔIi = I_avg - Ii.

[0051] Step S140, PI regulation: Input ΔIi into the PI regulator, and the PI regulator outputs a correction amount ΔIref_i for a current reference value.

[0052] Here, the correction amount ΔIref_i can also be subjected to amplitude limiting.

[0053] Step S150, Instruction issuance: The main control module sends the corrected current reference value Iref_i = Ibase + ΔIref_i to the corresponding power module via the CAN bus, where Ibase is the reference current.

[0054] Step S160, Module Response: The power module adjusts the phase shift angle of its internal AC / DC bidirectional converter according to the received Iref_i, changes the equivalent output voltage of the power module, and then adjusts the output current of the power module so that its output current approaches the average current.

[0055] Thus, for step S100, a dual parallel current sharing control strategy of "digital current sharing + circulating current compensation" is implemented, which can dually control the amplitude balance and waveform quality of the output current of multiple parallel power modules, ensuring the stable operation of multiple modules.

[0056] In another preferred embodiment, the charging mode further includes switching between trickle charging, constant current charging, and constant voltage charging during the charging process based on the vehicle's battery voltage. For example, the switching is performed under the following conditions: 1) Trickle charging is performed when the battery voltage is lower than the set low-voltage threshold. The low-voltage threshold is typically set to 60%-70% of the vehicle battery pack's rated voltage. This is intended to wake the battery with a small current and avoid damaging it with a large current surge.

[0057] 2) When the battery voltage is greater than or equal to the low-voltage threshold and less than the set constant-voltage threshold, constant-current charging is performed. The constant-voltage threshold is typically set to 80%-90% of the vehicle battery pack's rated voltage. In this case, the battery is charged quickly with the maximum permissible current to shorten the charging time.

[0058] 3) When the battery voltage is equal to or greater than the constant voltage threshold, constant voltage charging is performed. The main control module controls the output voltage of the power module to stabilize at the set charging voltage, at which point the charging current will naturally decrease. This stage involves gradually reducing the current to fully charge the battery, avoiding overcharging. Furthermore, if the battery voltage is greater than the constant voltage threshold for more than a preset safe time, or if the voltage difference between the two exceeds a preset safe tolerance range, charging is stopped, and the main control module can report an overvoltage fault.

[0059] The main control module determines the corresponding charging current or charging voltage based on the demand current and demand voltage messages sent by the vehicle BMS, and sends corresponding instructions to the power module.

[0060] Specifically, during the switch from constant current charging to constant voltage charging, the final current value of the constant current charging stage is used as the starting reference current of the constant voltage charging stage. From the perspective of the control algorithm, this is equivalent to using the current controller's output state value at the current moment as the initial state value of the voltage controller in the next stage, avoiding output jumps at the moment of switching and achieving a disturbance-free switching.

[0061] In step S200, in discharge mode, the power module is controlled to invert the DC power from the vehicle's battery into AC power and feed it into the power grid.

[0062] For example, step S200 may include the following discharge control sub-steps: receiving scheduling instructions from the grid EMS (Energy Management System) or cloud platform to obtain the discharge power target value P_target; sending a discharge request to the vehicle BMS (Battery Management System) to confirm that the battery is allowed to discharge; the main control module controls the AC / DC bidirectional converter to operate in inverter mode, inverting the battery DC power to AC power and feeding it into the grid; using a dq coordinate system dual closed-loop control algorithm to adjust the inverter output power in real time to track the target value; executing multiple safety protections such as anti-islanding protection, overcurrent protection, and overtemperature protection; monitoring the battery SOC status, and stopping discharge when the SOC drops to the user-set minimum allowable value. The dq coordinate system dual closed-loop control algorithm is one of the most classic control strategies in the field of power electronics (especially three-phase AC system control), and its details will not be elaborated here.

[0063] Through steps S100-S200 above, especially step S100, this embodiment of the application combines a three-phase Vienna PFC topology with V2G bidirectional charging and discharging functionality. Addressing the inherent zero-sequence circulating current problem of this topology, a compensation voltage regulation mechanism based on circulating current error is introduced, effectively suppressing zero-sequence circulating current between parallel power modules. This embodiment fills the technical gap in the V2G field for active compensation control of zero-sequence circulating current in three-phase Vienna PFC topologies, enabling the efficient, low-harmonic, and low-cost three-phase Vienna PFC topology to be applicable to V2G bidirectional charging and discharging scenarios. Furthermore, this embodiment helps improve the current sharing characteristics when power modules are connected in parallel, increasing system efficiency and reliability, and reducing additional losses, heat generation, and electromagnetic interference caused by circulating current, enabling stable output of high-power (≥150kW) DC fast charging.

[0064] In summary, the embodiments of this application do not simply superimpose the characteristics of the three-phase Vienna PFC topology, the zero-sequence circulating current active compensation algorithm, and the parallel current sharing control algorithm, but rather achieve deep synergistic adaptation with V2G bidirectional charging and discharging conditions, overcoming the inherent biases and defects of the prior art. Specifically, this involves the following aspects of synergy: 1. Synergy between the characteristics of the three-phase Vienna PFC topology and the zero-sequence circulating current active compensation algorithm.

[0065] The Vienna PFC topology has a "physical defect" because the midpoint of the DC bus is directly connected to the N line, forming a zero-sequence loop path. However, the zero-sequence loop path of the Vienna PFC topology is deterministic and fixed, unlike the non-fixed zero-sequence loop path of other topologies, which facilitates accurate modeling.

[0066] Therefore, this application embodiment establishes an accurate mathematical model of the zero-sequence circulating current path, and based on this mathematical model, calculates the compensation voltage in real time through a PR controller, etc., to directly offset the voltage difference causing the circulating current. That is, this application embodiment transforms the "physical defect" of the Vienna PFC topology into a "model advantage" (accurate modeling), enabling the compensation algorithm to offset the circulating current in a feedforward manner, rather than passively suppressing it.

[0067] 2. Synergy between zero-sequence circulating active compensation algorithm and parallel flow sharing control algorithm.

[0068] In the examples of this application, an RP controller is used to execute the zero-sequence circulating current active compensation algorithm, and a PI controller is used to execute the parallel current sharing control strategy. By using different controller types and control objectives, the two algorithms can work in parallel without interfering with each other. Furthermore, the zero-sequence circulating current active compensation algorithm is responsible for "waveform quality," while the current sharing control is responsible for "amplitude equalization," forming a dual parallel control strategy that can perform dual control on the amplitude equalization and waveform quality of the output current.

[0069] 3. Topology characteristics and V2G bidirectional charging and discharging conditions.

[0070] There is a technical bias in the existing technology: the three-phase Vienna PFC is a unidirectional topology, which is not suitable for V2G bidirectional scenarios. The embodiments of this application retain the Vienna PFC topology to take advantage of its high efficiency, low harmonics and low cost. On the other hand, it adopts a topology cascade of "Vienna PFC + DAB-ISOP" to realize the V2G bidirectional charging and discharging function through the bidirectional power transmission feature of DAB-ISOP.

[0071] Example 2 Figure 3The schematic diagram illustrates a structural block diagram of a control device according to an embodiment of this application. The control device may include: a memory configured to store instructions; and a processor configured to retrieve instructions from the memory and, when executing the instructions, to implement the charge-discharge control method of Embodiment 1 described above.

[0072] Preferably, the control device is an STM32F103RCT6 microcontroller capable of running the FreeRTOS real-time operating system.

[0073] In this example, the control device is preferably configured using an STM32F103RCT6 chip, which can be used as the main control module for building a V2G bidirectional charging and discharging pile. The STM32F103RCT6 chip (64 pins, 256KB Flash, 48KB RAM) has an ARM Cortex-M3 core with a 72MHz clock speed and can run the FreeRTOS real-time operating system. It achieves parallel processing through multi-task scheduling, handling asynchronous events such as communication protocol parsing, user interaction, and fault monitoring that may be involved in Example 1. The system task division is shown in the table below:

[0074] It should be noted that in charging control systems involving personal safety or high real-time requirements, a preemptive scheduling strategy should be adopted to ensure that the protection logic can be executed in a timely manner.

[0075] The task scheduling architecture is based on the FreeRTOS real-time operating system and adopts a preemptive scheduling strategy to ensure that the logic response time is ≤10ms.

[0076] Furthermore, the STM32F103RCT6 chip integrates a rich set of peripheral interfaces, including 2 CAN communication interfaces, 3 USART interfaces, 2 SPI interfaces, 3 12-bit ADCs, and multiple GPIOs. The specific interface allocation for this chip is shown in the table below:

[0077] In summary, when the control device of this application embodiment is used as the main control unit of the V2G bidirectional charging and discharging pile, it can run the FreeRTOS real-time operating system. Through multi-task scheduling and rich interface design, it can realize functions such as GB / T 27930 protocol parsing, power module parallel current sharing, V2G bidirectional charging and discharging control, fault protection, LVGL display, OCPP cloud communication and RS485 meter reading.

[0078] Example 3 Figure 4 The diagram schematically illustrates the functional structure of a V2G bidirectional charging and discharging pile according to an embodiment of this application. Figure 4As shown, the V2G bidirectional charging and discharging station includes: multiple power modules connected in parallel, wherein the multiple power modules include a DC / DC bidirectional converter using a DAB-ISOP topology and an AC / DC bidirectional converter using a three-phase Vienna PFC topology, and the DC / DC bidirectional converter and the AC / DC bidirectional converter use silicon carbide MOSFET power devices (SiCMOSFET); and a main control module for performing power control, wherein the main control module is configured to integrate the control device of Embodiment 2.

[0079] For details regarding the main control module, please refer to Embodiment 2; it will not be repeated here.

[0080] This design employs a topology with multiple power modules connected in parallel, enabling flexible power expansion through modular design. The AC / DC bidirectional converter and the DC / DC bidirectional converter are described in detail below.

[0081] (1) AC / DC bidirectional converter: The three-phase Vienna PFC topology is adopted to convert the three-phase AC power into a stable DC bus voltage. This topology uses SiC MOSFETs and utilizes the high voltage withstand, low on-resistance and high-speed switching characteristics of silicon carbide material to achieve high-frequency and high-efficiency energy conversion. The AC / DC bidirectional converter can include multiple protection mechanisms such as over-temperature protection, over-voltage protection, under-voltage protection and over-current protection.

[0082] (2) DC / DC bidirectional converter: adopts DAB (dual active bridge) topology, and achieves high voltage and high current output by connecting the primary side in series and the output in parallel. While maintaining system reliability and efficiency, it breaks through the physical bottleneck of voltage level and current capacity of a single converter.

[0083] In the example, referring to Embodiment 1, parallel current sharing control is performed on the parallel power modules: a digital current sharing control strategy is adopted, the main control module collects the output current of each module in real time, and adjusts the current reference value of each module through the PI regulator to realize the current sharing control between modules; for non-isolated AC / DC topology, a zero-sequence circulating current mathematical model is established, and circulating current between modules is eliminated through circulating current compensation control.

[0084] Further reference Figure 4 The V2G bidirectional charging and discharging pile may further include: a communication module configured to have multiple interface circuits and a wireless communication unit; a human-machine interaction module configured to realize human-machine interaction; an energy metering module configured to perform energy detection on the V2G bidirectional charging and discharging pile and provide energy detection results to the main control module; and a safety protection module configured to have an overcurrent protection unit, an overvoltage / undervoltage protection unit, an overtemperature protection unit, an insulation monitoring unit, a reverse connection protection unit, an anti-islanding protection unit, and / or an emergency stop switch.

[0085] The communication module includes multiple interface circuits such as CAN interface circuit, RS485 interface circuit, Ethernet interface circuit, and display interface circuit, while the wireless communication unit includes a 4G wireless module and a 5G wireless module. In this example, the interface circuits are designed as follows: (1) CAN interface circuit: An ISO1050 isolated CAN transceiver is used to realize isolated communication between the CAN controller and the CAN bus. The CAN interface circuit includes a TVS diode for bus surge protection, a common-mode choke for common-mode noise suppression, and a 120Ω terminating resistor. The CAN communication network between the charging pile and the vehicle BMS adopts the CAN2.0B communication protocol.

[0086] (2) RS485 interface circuit: The ADM2483 isolated RS485 transceiver chip is used to communicate with the electricity meter and read accurate electricity data.

[0087] (3) Ethernet interface circuit: The LAN8720A PHY chip is used and connected to the MAC controller of STM32 through the RMII interface to realize 10 / 100M Ethernet communication.

[0088] (4) Display interface: The touch screen is connected via an SPI interface to realize the human-computer interaction interface.

[0089] Furthermore, strong and weak current isolation was designed for the interface circuit, including: the relay drive circuit uses optocouplers to achieve strong and weak current isolation, ensuring that the weak current control part is protected from strong current interference. Thus, the current sampling signal is sent to the main control module (STM32 ADC) after being conditioned by the operational amplifier. The power supply ground of the sampling resistor is strictly shared with the ADC reference voltage to prevent systematic deviations in the measurement.

[0090] The human-computer interaction module is equipped with a touch screen, RFID reader, emergency stop button and status indicator lights.

[0091] For the electricity metering module, a three-phase smart electricity meter can be used.

[0092] Regarding the safety protection module, it should be noted that it is used during bidirectional charging and discharging to implement safety protection functions such as overcurrent protection, overvoltage / undervoltage protection, overtemperature protection, insulation monitoring, reverse connection protection, and anti-islanding protection. In the example, the multi-level safety protection implemented in V2G discharge mode is shown in the table below:

[0093] In summary, the V2G bidirectional charging and discharging pile provided in Embodiment 3 of this application has at least the following advantages: (1) By adopting a three-phase Vienna PFC topology and a DAB-ISOP topology cascaded AC / DC+DC / DC architecture, and in conjunction with silicon carbide MOSFET power devices, a bidirectional charging and discharging function with high efficiency, high power density and wide voltage range adaptability is realized.

[0094] (2) The parallel design of multiple power modules provides redundancy and fault tolerance as well as flexible expansion capability.

[0095] (3) The main control module can integrate control strategies such as zero-sequence circulating current compensation, smooth switching between charging and discharging, and dq dual closed-loop control, which significantly improves the dynamic performance and stability of the system.

[0096] (4) The communication module supports multiple interfaces such as CAN, RS485, Ethernet and wireless, realizing seamless interaction with vehicle BMS, power grid EMS and cloud platform.

[0097] (5) The safety protection module covers overcurrent, overvoltage, overtemperature, insulation monitoring, anti-islanding, reverse connection protection and emergency stop switch, and constructs a complete hardware and software collaborative safety system.

[0098] Example 4 Figure 5 This diagram schematically illustrates the functional structure of a control system for a V2G-based bidirectional charging and discharging pile according to an embodiment of this application. Figure 5 As shown, the control system includes: the V2G bidirectional charging and discharging pile described in Embodiment 3; and a cloud platform, vehicle BMS, and power grid EMS that communicate with the V2G bidirectional charging and discharging pile.

[0099] The communication protocol stack between the V2G bidirectional charging and discharging pile and the vehicle BMS includes the GB / T 27930 protocol, the ISO 15118-20 V2G protocol, and the J1939 protocol stack. Furthermore, the V2G bidirectional charging and discharging pile communicates bidirectionally with the cloud platform via the OCPP 2.0.1 protocol. Each protocol stack adopts a modular design, supporting dynamic loading and version updates. The protocol configuration of this embodiment helps solve problems such as insufficient compatibility of communication protocols between existing charging pile equipment and cloud operation platforms, poor modularity and configurability of the charging pile motherboard's protocol stack, and difficulty in quickly adapting communication protocols when charging standards are upgraded or new functions are added. The application of these protocols will be specifically described above with examples, and will not be repeated here.

[0100] In the example, such as Figure 6 As shown, a layered modular design is used to construct the control system of the V2G bidirectional charging and discharging pile. Figure 6 As shown, the order from bottom to top includes at least the following levels: (1) External equipment layer: including vehicle BMS, AC power grid EMS, vehicle power battery pack, smart energy meter, etc.

[0101] (2) Human-Machine Interface Layer: Includes a touch screen display, RFID reader, emergency stop button, and status indicator lights. The human-machine interface is built on an STM32F103 microcontroller and LVGL graphics library. It uses a 7-inch TFT color touch screen with a resolution of 800×480 and connects via an SPI interface. The UI includes a main interface, charging parameter interface, V2G mode interface, fault alarm interface, and settings interface, displaying real-time information such as charging pile operating mode, charging / discharging voltage / current / power, SOC, cumulative power, and fault information.

[0102] (3) Power conversion layer: includes AC / DC bidirectional converter and DC / DC bidirectional converter. The AC / DC section adopts a three-phase Vienna PFC topology, which can effectively reduce the voltage stress of power devices, has a higher switching frequency, and improves the power density of the system; the DC / DC section adopts a DAB-ISOP topology to achieve high-efficiency bidirectional energy conversion.

[0103] (4) Main control layer: The main control module is built based on the STM32F103 microcontroller, adopts the ARM Cortex-M3 core, runs the FreeRTOS real-time operating system, and achieves parallel processing through multi-task scheduling.

[0104] (5) Communication network layer: includes CAN bus communication network, Ethernet communication network, 4G / 5G wireless communication network and RS485 bus network.

[0105] (6) Cloud platform layer: Configure a charging station management system located in the cloud to control multiple charging piles in the charging station.

[0106] Building upon this foundation, this example achieves full-stack communication protocol compatibility, including modular integration of multiple protocol stacks such as GB / T 27930, ISO15118, OCPP 2.0.1, and J1939. This ensures interoperability with different vehicle brands and operator platforms, and provides excellent protocol scalability. The protocol stacks involved are described in detail below.

[0107] (1) GB / T 27930 Protocol Stack. This example implements the GB / T 27930 charging communication protocol at the vehicle communication level. The charging pile motherboard establishes a connection with the vehicle BMS through the CAN bus, following the standard message format and communication process. The communication process includes the handshake stage, parameter configuration stage, charging stage, fault handling, and charging end.

[0108] (2) J1939 Protocol Stack. The system implements the J1939 protocol stack based on CAN2.0B, and fully defines the physical layer, data link layer, network layer, and application layer. The protocol stack supports multi-frame transmission, address declaration, parameter group number parsing, error handling, and dual CAN channel redundancy switching.

[0109] (3) ISO 15118 V2G communication protocol. To realize the V2G bidirectional charging and discharging function, this example implements the ISO 15118 V2G communication protocol stack, including plug & charge automatic authentication, V2G bidirectional power transmission negotiation, dynamic charging scheduling and secure communication.

[0110] (4) OCPP communication protocol. At the cloud communication level, the system implements the OCPP 2.0.1 communication protocol to support standardized communication between the charging pile and the charging station management system, including status reporting, remote control, local caching and breakpoint resume, and security mechanisms.

[0111] In this example, the system of this application embodiment is applied to the mining field. That is, a large number of electric heavy trucks, loaders, and other mining vehicles are used as distributed energy storage resources to participate in grid frequency regulation, thereby transforming these mining vehicles from simple "energy-consuming devices" into "mobile energy storage units." Specifically, as... Figure 7 As shown, this example implements high-power intelligent DC fast charging and V2G bidirectional charging and discharging control for mining vehicles through the following steps S1-S8.

[0112] Step S1: System initialization.

[0113] After the charging pile is powered on, the main control chip (using automotive-grade / industrial-grade MCUs, such as STM32G4 or Infineon TC series, adaptable to wide temperature ranges of -40℃ to 85℃ and strong vibration environments in mining areas) performs system initialization, including clock configuration, peripheral initialization, FreeRTOS kernel startup, adaptive identification of the mining power grid (diesel generator grid, photovoltaic energy storage microgrid, or weak grid), initialization of the mining communication protocol stack, and mining self-test of the power module (which can be enhanced with functions such as emergency stop and safety circuit self-test, insulation resistance detection, explosion-proof cavity air pressure monitoring, and cooling fan dustproof self-cleaning detection). After the self-test passes, the system enters standby mode and reports the "ready" status to the host computer (mining area dispatch center).

[0114] Step S2, vehicle connection detection and handshake.

[0115] When a mining vehicle connects to a charging station via a charging gun (or a high-power pantograph / connector for mining, such as Mennekes or SBX series), the main control chip detects the connection status and auxiliary power supply status, while also checking whether the connector locking mechanism is in place. Due to the significant vibrations in the mining area, a dual "mechanical + electronic" verification system is employed.

[0116] After connection confirmation, the system initiates a handshake process: it prioritizes the GB / T 27930 standard handshake; if no response is received within a timeout period, it switches to the pre-configured private CAN protocol of the mining area. Upon successful handshake, it reads the mining area parameters sent by the miner's BMS. It should be noted that in addition to standard parameters, it also needs to obtain specific parameters such as the miner's maximum allowable discharge rate (energy feedback may be limited during heavy-load downhill runs in the mining area), the battery pack's explosion-proof rating, and the miner's current operating condition (loaded / unloaded / climbing / downhill). If the handshake fails, the system reports "protocol mismatch" through the mining area scheduling network and guides the operator to manually match the protocol via the human-machine interface.

[0117] Step S3: Parameter configuration and charging preparation.

[0118] The system receives battery parameter messages from the mining machine's BMS, parses parameters such as battery type, rated capacity, rated total voltage (supporting 800V~1500V high-voltage platforms), current SOC, required voltage, and required current. Based on the battery parameters and the charging pile's capacity (maximum output power up to 600kW~1.2MW), it calculates the maximum charging power that can be provided and sends the configuration parameters to the BMS for confirmation. It should be noted that if the current power of the mining area's microgrid is limited (e.g., insufficient photovoltaic output or diesel generator overload), the system automatically adjusts the maximum promised power and notifies the mining machine's BMS.

[0119] Step S4: Determine the working mode.

[0120] Four operating modes are defined: AC / DC charging mode, DC / AC grid-connected inverter mode, off-grid inverter mode, and bidirectional operation mode. AC / DC charging mode, simply referred to as charging mode, is a conventional fast charging mode suitable for replenishing energy during miner standby or intermittent operation. DC / AC grid-connected inverter mode and off-grid inverter mode are collectively referred to as discharging mode, where the miner acts as a mobile energy storage device to discharge energy to the grid when the mining area's power grid requires support. In addition to the above four operating modes, energy feedback mode and operation coordination mode can also be included. Energy feedback mode refers to the automatic switching to regenerative braking mode when the miner is under heavy load and downhill conditions, feeding back the converted electrical energy to the mining area's power grid or energy storage system (no manual selection is required; it is automatically identified by the miner's BMS and charging pile). Operation coordination mode refers to the dynamic adjustment of charging and discharging power based on mining area dispatch instructions during loading / unloading waiting periods, achieving peak shaving and valley filling with "waiting as service."

[0121] Furthermore, the system comprehensively determines the operating mode based on user selection, instructions from the mining area dispatch center, and the current operating status of the mining machine. Once the operating mode is determined, the system reports the current mode and expected power to the mining area dispatch center.

[0122] Step S5, charging control.

[0123] In the example, the following charging control sub-step is executed: 1) Multi-module collaborative control: The main control chip sends voltage and current settings to each parallel power module via the CAN bus to start power output.

[0124] 2) Dynamic power tracking: Real-time acquisition of output voltage, output current and battery status information sent by BMS, superimposed with mine power grid load monitoring; when the mine power grid frequency fluctuates or the voltage drops, it automatically reduces power to avoid impacting the weak power grid.

[0125] 3) Three-stage charging strategy: Automatically switches between three stages: trickle charging, constant current charging, and constant voltage charging, and optimizes the switching threshold for each stage for large-capacity batteries (200kWh~800kWh) of mining machines.

[0126] 4) Multi-module parallel current sharing control: The current sharing algorithm ensures that the output current of each module is balanced, especially when the miner is charging with high current, the current sharing algorithm avoids local overheating.

[0127] 5) Charging process monitoring: Real-time monitoring of charging status and safety parameters; when an abnormality is detected, charging is immediately stopped and the fault is reported to the mine dispatch center.

[0128] 6) Charging complete: When the BMS sends a charging stop message or detects that the battery is fully charged, it executes the power-off sequence according to the mine safety regulations, stops power output, and ends the charging process.

[0129] Step S6, discharge control.

[0130] Perform the following discharge control sub-steps: 1) Conventional V2G Discharge: Receives scheduling instructions from the power grid EMS or cloud platform to obtain the discharge power target value P_target; sends a discharge request to the mining machine BMS to confirm that the battery SOC is higher than the minimum allowable value set in the mining area (usually 30%, higher than 20% for civilian vehicles, to reserve sufficient energy for mining operations), thus allowing discharge; the main control chip controls the AC / DC bidirectional converter to work in inverter mode, inverting the battery DC power to AC power and feeding it into the power grid; adopts a dq coordinate system dual closed-loop control algorithm to adjust the inverter output power in real time to track the target value; executes multiple safety protections such as anti-islanding protection, overcurrent protection, and overtemperature protection; monitors the SOC status, and stops discharging when the SOC drops to the minimum allowable value set by the user.

[0131] 2) Heavy-load downhill energy feedback mode: When the mining machine BMS detects that the vehicle is in a heavy-load downhill condition and the braking resistor starts to consume energy, the energy feedback mode is automatically triggered; the charging pile receives the energy fed back by the mining machine and feeds the DC power back to the DC bus in the mining area or the vehicle-mounted energy storage system; the control algorithm switches from "constant current charging" to "constant power feedback" to track the changes in the mining machine's braking power in real time; if the DC bus voltage in the mining area exceeds the safety threshold (such as 1050V), the unloading circuit (braking resistor) is automatically switched on to consume the excess energy.

[0132] 3) Isolated / Black Start Support Mode: When the mining area microgrid is disconnected from the main grid due to a fault (isolated operation), mining machines with V2G functionality can act as black start power sources to support critical loads in the mining area. At this time, the charging piles operate in VF (voltage / frequency) source mode, establishing the voltage and frequency reference (380V / 50Hz) for the mining area microgrid; other mining machines can connect to the same microgrid for charging, forming a temporary microgrid for "mining machine mutual support".

[0133] Step S7: Process monitoring and fault handling.

[0134] Throughout the charging and discharging process, the system monitors the following parameters in real time and executes corresponding fault handling strategies: 1) Overcurrent fault: Cut off power output within 1ms and report the fault location to the mine dispatch center at the same time.

[0135] 2) Overvoltage / undervoltage fault: Immediately stop power transmission. If the voltage of the mining area power grid is abnormal, automatically switch to island protection mode.

[0136] 3) Overheating fault: First reduce power and run. If the temperature continues to rise, stop the machine and start the cooling fan for a delayed cooling period.

[0137] 4) Insulation fault: The high-voltage circuit is cut off and an alarm is triggered, which triggers the "leakage interlock" in the mine safety regulations and requires manual reset.

[0138] 5) Communication failure: If the communication fails after 3 attempts, stop charging and discharging and notify the miner operator to check the connection.

[0139] 6) Vibration exceeding limits: The system detects collision or overturning conditions using an acceleration sensor. If the collision or overturning of the mining machine is detected, the high voltage is cut off and the contactor is locked within 100ms.

[0140] 7) Emergency stop signal: Unconditionally cuts off all power output.

[0141] Step S8: Data reporting and settlement.

[0142] After charging and discharging are completed, the main control chip reads the cumulative charging / discharging amount from the energy meter, calculates the cost, and generates a charging / discharging record. This record may include: miner number, operator ID, start and end time, charging amount, discharging amount, microgrid frequency / voltage fluctuation records, and fault event logs. Furthermore, the system reports the charging / discharging record to the cloud platform via Ethernet / 4G network, while simultaneously storing the record in local Flash memory as a backup. The cloud platform is equipped with a mine production scheduling system, which automatically updates the miner's "energy status" based on the charging / discharging record, allowing the scheduling system to optimize mine truck operation plans, such as prioritizing miners with sufficient power for long-distance transportation tasks.

[0143] In summary, the control system for V2G bidirectional charging and discharging piles in this application has the following advantages: I. High-efficiency bidirectional energy conversion. Specifically, employing SiC power devices and an optimized DAB topology, the AC / DC charging efficiency reaches over 95.5%, with round-trip efficiency losses lower than the industry average, significantly reducing energy waste and heat dissipation burden during high-power charging (600kW~1.2MW) of mining rigs. The system supports a wide voltage range of 200-1000Vdc, adapting to mainstream 800V / 1500V high-voltage platforms for mining rigs, and is compatible with various batteries and vehicle models.

[0144] II. Intelligent V2G Dispatch Capability. Standardized V2G bidirectional power transmission is achieved through the ISO 15118-20 protocol, supporting mining machines as mobile energy storage units to participate in peak shaving, frequency regulation, and demand response in the mining area microgrid. Mining machines can provide support to the mining area power grid during standby, loading waiting, and nighttime shutdown periods. Specific applications include, but are not limited to, peak shaving and valley filling, energy feedback during heavy load downhill runs, and support for islanded / black start operations. This transforms mining machines from "pure cost centers" into "profitable mobile energy storage assets," improving the economics of electricity use in mines.

[0145] III. High-Reliability Multi-Module Parallel Current Sharing. Through digital current sharing control strategies and zero-sequence circulating current suppression algorithms, the system effectively solves the problems of uneven current sharing and circulating current when multiple power modules are connected in parallel, achieving stable output of high-power (≥150kW) DC fast charging. The current sharing technology avoids single-module overload and extends the service life of power modules in the high-temperature and dusty environment of mining areas.

[0146] IV. Full-Stack Communication Protocol Compatibility: The system implements modular integration of multiple protocol stacks, including GB / T 27930, ISO 15118, OCPP 2.0.1, and J1939, ensuring interoperability with different vehicle brands and operator platforms, and possessing excellent protocol expansion capabilities. Multi-protocol compatibility avoids redundant investment in building multiple charging facilities in mining areas due to the mixed vehicle brands; it also facilitates deep coupling between the mining area's EMS and dispatch systems, achieving collaborative optimization of the "mining machine-charging pile-grid" system.

[0147] V. High Real-Time Performance and Security: Based on the FreeRTOS real-time operating system, the task scheduling architecture adopts a preemptive scheduling strategy, ensuring a protection logic response time of ≤10ms. The system features multiple protections including over-temperature, over-voltage, under-voltage, over-current, and insulation monitoring, making it adaptable to harsh environments such as high humidity and dust, with a design life of up to 10 years.

[0148] VI. Rich Human-Machine Interaction Experience and Remote Operation and Maintenance: A high-performance embedded graphical interface built on STM32 and LVGL provides a smooth interactive experience, supporting touch control, real-time data visualization, and remote monitoring and management, enhancing user convenience. Data is uploaded to the mining area dispatch center via 4G / 5G or the mining area's industrial Ethernet ring network, supporting remote start / stop, parameter configuration, and OTA upgrades. The rich human-machine interaction experience reduces operator training costs; the icon-based interface requires no specialized knowledge to operate, while remote operation and maintenance reduces the need for on-site maintenance manpower, making it particularly suitable for high-altitude and remote mines.

[0149] This application also provides a machine-readable storage medium storing instructions that cause a machine to perform the charge / discharge control method described in Embodiment 1.

[0150] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0151] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0152] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0153] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0154] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0155] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0156] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0157] It should also be noted that 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. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0158] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A charging and discharging control method based on V2G bidirectional charging and discharging piles, characterized in that, The V2G bidirectional charging and discharging station is configured with multiple power modules connected in parallel and a main control module for power control. The multiple power modules include at least an AC / DC bidirectional converter using a three-phase Vienna PFC topology and a DC / DC bidirectional converter using a DAB-ISOP topology. The charging and discharging control method is executed by the main control module and includes: In charging mode, the power module is controlled to convert AC power from the grid into DC power to charge the vehicle's battery, and zero-sequence circulating current compensation is performed during the charging process. This zero-sequence circulating current compensation includes: adjusting the compensation voltage allocated to each AC / DC bidirectional converter in the zero-sequence circulating current path based on the circulating current error between the total zero-sequence circulating current value and the target circulating current value of the zero-sequence circulating current path formed by multiple AC / DC bidirectional converters connected in parallel, to offset the voltage difference between the AC / DC bidirectional converters that generate zero-sequence circulating current. The total zero-sequence circulating current value of the zero-sequence circulating current path is the sum of the measured zero-sequence currents of each AC / DC bidirectional converter in the zero-sequence circulating current path. In discharge mode, the power module is controlled to invert the DC power from the vehicle's battery into AC power and feed it into the power grid.

2. The charging and discharging control method according to claim 1, characterized in that, The adjustment of the compensation voltage allocated to each AC / DC bidirectional converter in the zero-sequence loop includes: The circulating current error is input to a preset linear controller to output a total compensation voltage value used to offset the voltage difference; and Based on the real-time operating conditions of each AC / DC bidirectional converter, the total compensation voltage value is allocated to each AC / DC bidirectional converter to obtain a corresponding compensation voltage. This compensation voltage is mapped to the duty cycle correction amount of the corresponding AC / DC bidirectional converter to adjust the PWM signal used to drive the switching transistor of the AC / DC bidirectional converter.

3. The charging and discharging control method according to claim 1, characterized in that, It also includes current sharing control during the charging process, wherein the current sharing control includes: correcting the output current of the corresponding power module based on the current error between the real-time output current of each power module and the average output current of all power modules.

4. The charging and discharging control method according to claim 1, characterized in that, It also includes switching between trickle charging, constant current charging, and constant voltage charging during the charging process based on the vehicle's battery voltage, including: When the battery voltage is lower than the set low-voltage threshold, the trickle charging is performed; When the battery voltage is greater than or equal to the low-voltage threshold and less than the set constant-voltage threshold, the constant-current charging is performed; and When the battery voltage is equal to or greater than the constant voltage threshold, constant voltage charging is performed, and if the battery voltage is greater than the constant voltage threshold for a period of time exceeding a preset safe time or the voltage difference between the two exceeds a preset safe tolerance range, then charging is stopped. In the process of switching from constant current charging to constant voltage charging, the final current value of the constant current charging stage is used as the starting reference current of the constant voltage charging stage.

5. A control device, characterized in that, include: The memory is configured to store instructions; as well as The processor is configured to retrieve the instructions from the memory and, when executing the instructions, to implement the charge / discharge control method according to any one of claims 1 to 4.

6. The control device according to claim 5, characterized in that, The control device is an STM32F103RCT6 microcontroller capable of running the FreeRTOS real-time operating system.

7. A V2G bidirectional charging and discharging pile, characterized in that, include: Multiple power modules connected in parallel, wherein the multiple power modules include a DC / DC bidirectional converter using a DAB-ISOP topology and an AC / DC bidirectional converter using a three-phase Vienna PFC topology, and wherein the DC / DC bidirectional converter and the AC / DC bidirectional converter employ silicon carbide MOSFET power devices; and A main control module for performing power control, wherein the main control module is configured to integrate the control device as described in claim 5 or 6.

8. The V2G bidirectional charging and discharging pile according to claim 7, characterized in that, Also includes: The communication module is configured to have multiple interface circuits and a wireless communication unit, the multiple interface circuits including a CAN interface circuit, an RS485 interface circuit, an Ethernet interface circuit and a display interface circuit; The human-computer interaction module is configured to enable human-computer interaction. The power metering module is configured to detect power consumption of the V2G bidirectional charging and discharging pile and provide the power consumption detection results to the main control module. as well as The safety protection module is configured with an overcurrent protection unit, an overvoltage / undervoltage protection unit, an overtemperature protection unit, an insulation monitoring unit, a reverse connection protection unit, an anti-islanding protection unit, and / or an emergency stop switch.

9. A control system for a V2G bidirectional charging and discharging pile, characterized in that, include: The V2G bidirectional charging and discharging pile as described in claim 7 or 8; and The cloud platform, vehicle battery management system (BMS), and power grid energy management system (EMS) that communicate with the V2G bidirectional charging and discharging pile; The communication protocol stack between the V2G bidirectional charging and discharging pile and the vehicle BMS includes the GB / T 27930 protocol, the ISO15118-20 V2G protocol, and the J1939 protocol stack. The V2G bidirectional charging and discharging pile communicates bidirectionally with the cloud platform via the OCPP 2.0.1 protocol.

10. The control system according to claim 9, characterized in that, The vehicle in question is a mining vehicle.

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