Intelligent charging pile core module based on VIENNA structure, electric energy quality treatment method, system and equipment and storage medium

Abstract

The invention discloses an intelligent charging pile core module based on a VIENNA structure, an electric energy quality management method, system and equipment and a storage medium, and belongs to the field of electric power system energy storage equipment.The intelligent charging pile core module based on the VIENNA structure comprises the steps that an integrated power conversion unit is constructed, the power conversion unit adopts a VIENNA rectifier topology, three-phase alternating current is converted into direct current, and the direct current is converted into direct current; a harmonic suppression structure linked with the control interface is arranged; state information in the operation process is collected and serves as input of the control strategy module; based on the state information, a modulation control instruction is generated in the control strategy module to drive the switching action of the power conversion unit; on the basis of the modulation control instruction, the switch control is executed, meanwhile, the direct-current side midpoint potential of the power conversion unit is synchronously adjusted, and the distribution of direct-current bus capacitor voltage is controlled; and identifying the current operation condition according to the state information, switching to a control template corresponding to the operation condition in the control strategy module, and generating a modulation control instruction.

Description

Technical Field

[0001] This invention relates to the field of power electronic conversion technology, specifically to a core module of a smart charging pile based on the VIENNA structure, as well as a power quality management method, system, device, and storage medium. Background Technology

[0002] Currently, smart charging piles generally use two-level PWM rectifiers as the core of AC / DC conversion, paired with independent active filters for harmonic mitigation. In this scheme, the two-level rectifier achieves power conversion through high-frequency switching; however, due to topology limitations, its output voltage has a high harmonic content, requiring an external LC filter to suppress electromagnetic interference, leading to increased system size and cost. Simultaneously, the active filter dynamically compensates for grid harmonics based on instantaneous reactive power theory; however, because the charging pile and active filter use a separate control architecture, their dynamic responses are mismatched, easily causing harmonic amplification or compensation lag. In terms of control strategy, traditional PI regulators rely on linearized models, making it difficult to adapt to the wide load range of charging piles or grid voltage distortion conditions, easily resulting in regulation overshoot or oscillation. Furthermore, the independent active filter requires additional system capacity and suffers significant losses under light loads. With the increasing demand for high-power fast charging, the limitations of this scheme in terms of efficiency, cost, and dynamic performance are becoming increasingly prominent.

[0003] Existing power quality management solutions for charging piles based on two-level rectifiers and independent active power filters have significant technical limitations: their fixed-parameter PI control strategy struggles to adapt to dynamic operating conditions during charging, leading to insufficient or over-compensation of harmonics when the load changes abruptly or the grid voltage distorts; design methods relying on simplified linear models cannot accurately characterize the nonlinear characteristics of power electronic devices and system coupling effects, resulting in significant deviations between actual compensation effects and theoretical expectations; the discrete architecture of the active power filter exhibits response delays, failing to suppress harmonics in a timely manner during transient processes such as charging start-up and shutdown; furthermore, the lack of a collaborative optimization mechanism between the rectifier and the active power filter not only increases additional system capacity requirements but also leads to efficiency degradation under light load conditions. These shortcomings are particularly pronounced in high-power fast charging and high-proportion renewable energy integration scenarios, severely restricting the effectiveness of power quality management and operational efficiency of charging piles.

[0004] To address the problems of rigid control strategies, insufficient model adaptability, lag response, and lack of collaborative optimization in existing charging pile power quality management solutions, especially given the increased harmonic content and complex dynamic characteristics of the grid due to high-power fast charging and high proportion of renewable energy grid connection, the traditional discrete architecture of two-level rectifier + active filter struggles to simultaneously meet the dual requirements of efficient power conversion and high-quality harmonic mitigation. To solve these technical challenges, this invention proposes a smart charging pile core module based on the VIENNA structure and a power quality management method. Summary of the Invention

[0005] To address the aforementioned technical issues, a core module for a smart charging pile based on the VIENNA structure and a power quality management method are proposed. This includes constructing an integrated power conversion unit, which adopts a VIENNA rectifier topology to convert three-phase AC power into DC power, and setting a harmonic suppression structure linked to the control interface.

[0006] Collect status information during operation and use it as input to the control strategy module;

[0007] Based on the state information, modulation control commands are generated in the control strategy module to drive the switching action of the power conversion unit.

[0008] Based on modulation control commands, while executing switching control, the DC side midpoint potential of the power conversion unit is synchronously adjusted to control the distribution of DC bus capacitor voltage.

[0009] Based on the status information, the current operating condition is identified, and the control strategy module switches to the control template corresponding to the operating condition, and the modulation control command is regenerated.

[0010] As a preferred embodiment of the core module of a smart charging pile based on the VIENNA structure and the power quality management method described in this invention, the integrated power conversion unit adopts a VIENNA rectifier topology to convert three-phase AC power into DC power, and includes a harmonic suppression structure linked to the control interface.

[0011] Configure the input inductor to limit the rate of rise of the input current and form a continuous current path;

[0012] By setting up series-connected positive and negative bus capacitors, a three-level output structure is formed, creating a node interface for DC midpoint adjustment.

[0013] The power conversion unit is modulated and controlled using a three-level space vector pulse width modulation method. Based on the modulation command output by the control strategy module, the input AC current is dynamically shaped.

[0014] As a preferred embodiment of the core module of a smart charging pile based on the VIENNA structure and the power quality management method described in this invention, the step of collecting status information during operation and using it as input to the control strategy module includes:

[0015] The effective values ​​and phase information of the three-phase voltage and three-phase current on the input side are obtained to determine the power factor relationship between the input current and voltage.

[0016] Monitor the total harmonic distortion rate of the input current and extract the amplitude information of several specific harmonic components;

[0017] The instantaneous values ​​of the DC bus voltage and the neutral point-to-ground voltage are obtained, and the voltage ripple amplitude is calculated for use in neutral point potential regulation and control.

[0018] As a preferred embodiment of the core module of a smart charging pile based on the VIENNA structure and the power quality management method described in this invention, the step of generating modulation control commands in the control strategy module based on state information to drive the switching action of the power conversion unit includes:

[0019] In the control strategy module, a prediction structure based on a discrete state-space model is constructed to predict the changing trends of input current, voltage, and bus voltage over multiple future sampling periods.

[0020] Based on the error between the prediction results and the reference command, an objective function is defined and online rolling optimization is performed to generate the modulation reference quantity for the current cycle.

[0021] Based on the modulation reference value, a sliding mode surface function and a reaching law are constructed, and the output value of the control command is dynamically corrected according to the actual control error change rate.

[0022] The modified control commands are mapped to power conversion unit switching control quantities to adjust the modulation duty cycle of each phase bridge arm of the rectifier.

[0023] As a preferred embodiment of the core module of a smart charging pile based on the VIENNA structure and the power quality management method described in this invention, the step of synchronously adjusting the DC side midpoint potential of the power conversion unit while executing switch control based on modulation control commands, and controlling the distribution of the DC bus capacitor voltage, includes:

[0024] A disturbance observer is constructed based on the deviation between the measured value of the midpoint potential and the desired equilibrium point to estimate the equivalent disturbance that causes the potential imbalance.

[0025] A voltage equalization adjustment signal is generated based on the disturbance amount, and the adjustment signal is superimposed on the original modulation control command. In the superposition control, a combination of redundant small vectors or zero vectors with midpoint adjustment capability is adopted to change the midpoint current injection path.

[0026] By allocating the duration of different vector actions within the modulation period, the charge balance of the positive and negative bus capacitors on the DC side is adjusted.

[0027] As a preferred embodiment of the core module of a smart charging pile based on the VIENNA structure and the power quality management method described in this invention, the step of identifying the current operating condition based on status information, switching to the control template corresponding to the operating condition in the control strategy module, and regenerating modulation control commands includes,

[0028] Receive charging parameter information and obtain the target charging mode instruction for the current charging stage;

[0029] Analyze the real-time voltage waveform and frequency information of the input power grid to identify whether there is voltage distortion, drop or frequency deviation;

[0030] Based on the charging parameter information and the power grid status information, select the corresponding control template from the preset control strategy template library and load the control parameter structure of the selected template;

[0031] The control target setpoint is recalculated to match the current operating conditions, and modulation control commands are generated in combination with the status information.

[0032] As a preferred embodiment of the core module of a smart charging pile based on the VIENNA structure and the power quality management method described in this invention, the regeneration of modulation control commands includes:

[0033] After identifying changes in operating conditions, the modulation parameter output of the previous control template is maintained for several control cycles, and the state variables and control targets in the target control template are initialized synchronously.

[0034] Based on the difference between the target reference values ​​between the two control templates, a modulation transition curve is constructed, and the modulation control command is gradually and smoothly adjusted within a preset transition period.

[0035] The power conversion unit is controlled to respond cycle by cycle by updating the modulation control command, so as to complete the seamless switching of the working mode on the physical control path.

[0036] Another objective of this invention is to provide a core module for intelligent charging piles and a power quality management system based on the VIENNA structure. This invention addresses the problems of response lag, unstable modulation control, midpoint potential offset imbalance, and power quality disturbances in existing charging pile systems during multi-condition switching. It proposes a power conversion and management method based on a three-level VIENNA rectifier topology, fusion model predictive control, and adaptive sliding mode control strategy. Furthermore, it achieves modulation control, midpoint adjustment, and soft switching of control templates through the division of labor and collaboration among system modules, thereby improving the overall control stability and output quality.

[0037] As a preferred embodiment of the core module of the intelligent charging pile based on the VIENNA structure and the power quality management system described in this invention, it is characterized by including a power conversion execution module, a status information acquisition module, a control strategy module, and a pattern recognition and scheduling module.

[0038] The power conversion execution module receives modulation control commands and drives the switching action of the power conversion unit. Based on the three-level VIENNA rectifier topology, it realizes the energy conversion of three-phase AC to DC. During the energy conversion process, it synchronously adjusts the DC side midpoint potential according to the control commands to control the dynamic balance of the positive and negative capacitor voltages of the DC bus, thereby achieving stable control of the midpoint offset.

[0039] The status information acquisition module collects key electrical parameters during system operation, including input three-phase voltage and current, total harmonic distortion, DC output voltage, current and neutral-to-ground voltage. The collected status information characterizes grid fluctuations, power quality status and the degree of balance in the power conversion process, and serves as real-time feedback input for the control strategy module.

[0040] The control strategy module receives state information input, executes a composite control logic of model predictive control and adaptive sliding mode control, constructs an objective function based on the predictive model, and generates modulation control reference quantities through rolling optimization.

[0041] The pattern recognition and scheduling module receives charging stage parameters and grid operation status information output by the battery management system, identifies the current operating condition, selects the corresponding template from the preset control strategy template library according to the operating condition type, and performs control parameter initialization and smooth transition calculation of reference target quantity after the template is loaded. It works with the control strategy module to complete the continuous switching of working mode and real-time update of control commands.

[0042] A computer device includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of the core module of a smart charging pile based on the VIENNA structure and the power quality management method.

[0043] A computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the core module of a smart charging pile based on the VIENNA structure and the power quality management method described above.

[0044] The beneficial effects of this invention are as follows: Based on the three-level topology of the VIENNA rectifier, combined with a composite strategy of MPC and sliding mode control, integrated and coordinated optimization of power conversion and harmonic mitigation is achieved. By sensing the grid harmonic state and load characteristics in real time and dynamically adjusting control parameters, the system can accurately suppress the 6k±1st characteristic harmonic, maintain the midpoint potential balance, and maintain unity power factor operation under wide voltage range and dynamic load conditions, thus improving overall efficiency. This solution innovatively adopts an intelligent voltage equalization algorithm and a multi-mode switching mechanism. Compared with traditional solutions, it not only eliminates the hardware redundancy of independent active filters and reduces losses, but also supports V2G bidirectional energy interaction, effectively improving the adaptability of charging piles to high-proportion renewable energy grids, and providing key technical support for clean energy consumption and grid supply-demand balance. Attached Figure Description

[0045] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is an overall flowchart of a smart charging pile core module based on the VIENNA structure and a power quality management method provided in one embodiment of the present invention. Detailed Implementation

[0047] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0048] Example 1, referring to Figure 1 This is the first embodiment of the present invention, which provides a core module for a smart charging pile based on the VIENNA structure and a power quality management method, including:

[0049] S1. Construct an integrated power conversion unit. The power conversion unit adopts the VIENNA rectifier topology to convert three-phase AC power into DC power and is equipped with a harmonic suppression structure linked to the control interface.

[0050] Configure the input inductor to limit the rate of rise of the input current and form a continuous current path;

[0051] By setting up series-connected positive and negative bus capacitors, a three-level output structure is formed, creating a node interface for DC midpoint adjustment.

[0052] The power conversion unit is modulated and controlled using a three-level space vector pulse width modulation method. Based on the modulation command output by the control strategy module, the input AC current is dynamically shaped.

[0053] The specific structure of the VIENNA topology. Further, the three-phase, three-level VIENNA rectifier topology in step 1 specifically includes the following power conversion main circuit: at least one set of three-phase input inductors, multiple power switching devices, at least two series-connected DC bus support capacitors, a high-frequency isolation transformer (for achieving electrical isolation and voltage level matching, especially in situations requiring isolation), and an intelligent voltage equalization unit / circuit integrated into or closely cooperating with the main circuit to assist in achieving DC side midpoint potential balance. These components together constitute the physical basis for achieving efficient power conversion and integrated harmonic suppression.

[0054] Preferred Power Switching Devices. As a preferred technical solution, the power switching devices in the power conversion main circuit employ wide-bandgap semiconductor devices. SiC or GaN devices are used because they offer advantages such as higher voltage ratings, lower on-resistance, faster switching speeds, superior high-temperature characteristics, and lower drive losses. These advantages significantly improve the overall conversion efficiency, switching frequency, and power density of the VIENNA rectifier, and enhance the system's dynamic response performance, making them one of the key technical supports for achieving the beneficial effects described in this invention.

[0055] The modulation strategy is further specified. More specifically, the power conversion main circuit achieves high-efficiency AC / DC conversion and active harmonic suppression through an advanced three-level modulation strategy. Preferably, this modulation strategy is three-phase three-level space vector pulse width modulation (SVPWM) technology. SVPWM technology can effectively reduce switching losses, reduce input current ripple and output voltage ripple, and improve the utilization rate of DC bus voltage by optimizing the selection and action time of the switching vectors, and provides more control degrees of freedom for achieving precise current control and midpoint potential balance control. Alternatively, other efficient three-level modulation techniques, such as carrier interleaving modulation technology, can be used to achieve similar technical effects.

[0056] S2. Collect status information during operation and use it as input to the control strategy module.

[0057] The effective values ​​and phase information of the three-phase voltage and three-phase current on the input side are obtained to determine the power factor relationship between the input current and voltage.

[0058] Monitor the total harmonic distortion rate of the input current and extract the amplitude information of several specific harmonic components;

[0059] The instantaneous values ​​of the DC bus voltage and the neutral point-to-ground voltage are obtained, and the voltage ripple amplitude is calculated for use in neutral point potential regulation and control.

[0060] The power quality parameters and charging status parameters acquired in real time may include, but are not limited to: the instantaneous value, effective value, frequency, phase, and total harmonic distortion (THD) of the three-phase AC input voltage of the power grid; the instantaneous value, effective value, THD, and content or spectral distribution of harmonics of specific orders (e.g., 3rd, 5th, 7th, 11th, 13th, etc., 6k±1); the active power, reactive power, and apparent power on the input side, and the input power factor calculated accordingly; the instantaneous values ​​of the positive and negative DC bus voltages to ground, the average value of the total DC bus voltage, the ripple amplitude or ripple rate of the DC bus voltage; and the magnitude of the DC output current, etc. Comprehensive and accurate monitoring of these parameters provides detailed information for subsequent adaptive control.

[0061] S3. Based on the status information, a modulation control command is generated in the control strategy module to drive the switching action of the power conversion unit.

[0062] In the control strategy module, a prediction structure based on a discrete state-space model is constructed to predict the changing trends of input current, voltage, and bus voltage over multiple future sampling periods.

[0063] Based on the error between the prediction results and the reference command, an objective function is defined and online rolling optimization is performed to generate the modulation reference quantity for the current cycle.

[0064] Based on the modulation reference value, a sliding mode surface function and a reaching law are constructed, and the output value of the control command is dynamically corrected according to the actual control error change rate.

[0065] The modified control commands are mapped to power conversion unit switching control quantities to adjust the modulation duty cycle of each phase bridge arm of the rectifier.

[0066] In a preferred embodiment of the invention, generating modulation control commands in the control strategy module is a specific implementation mechanism of the hybrid control strategy. More specifically, in the hybrid control strategy combining model predictive control (MPC) and adaptive sliding mode control (SMC): the MPC unit, based on the established VIENNA rectifier system mathematical model, predicts the system state (such as input current, DC voltage, etc.) within a finite time step in each control cycle, and performs online rolling optimization of a series of control switching sequences to minimize a preset comprehensive cost function. This cost function comprehensively considers multiple control objectives, including the error of the input current tracking reference command, the harmonic content of the input current, the deviation of the grid-side power factor from the target value, and the deviation of the DC bus voltage from the set value.

[0067] The adaptive sliding mode control unit is designed with a specific sliding surface and a reaching law. Its function is to enhance the robustness of the system to parameter perturbations, external disturbances and unmodeled dynamics, and to ensure that the system state can quickly converge to the sliding surface and maintain sliding on it, thereby ensuring that the system has a fast dynamic response and good stability. In particular, when the system parameters change or there are uncertainties, it can adaptively adjust the control law to maintain performance.

[0068] The control objectives are specifically quantified. As the superior technical effect that this invention aims to achieve, the specific objectives of the adaptive cooperative control can be quantified as follows: through harmonic suppression control, the total harmonic distortion (THD) of the grid input current of the charging pile within its rated operating range is controlled at a low level; through reactive power compensation control, the input power factor on the grid side approaches unity power factor over a wide load range; and through DC voltage stabilization control, the fluctuation rate of the DC bus voltage is limited to a small allowable range under load abrupt changes or grid disturbances.

[0069] Hardware architecture of the adaptive control module. To meet the high real-time computing requirements of the aforementioned complex hybrid control strategies (especially the MPC algorithm), the adaptive control module preferably uses a high-performance digital signal processor (DSP) as its core processing unit. One specific implementation is a dual-DSP architecture, where one DSP may focus on executing the computationally intensive MPC algorithm, while the other DSP is responsible for tasks such as sliding mode control, low-level PWM modulation, data acquisition interface management, and communication with other modules. Alternatively, a heterogeneous computing architecture combining a field-programmable gate array (FPGA) and a DSP can be used, utilizing the FPGA for high-speed parallel processing and low-level logic control, while the DSP handles complex algorithm calculations and top-level strategy decisions.

[0070] In one optional embodiment of the invention, the modulation control command is generated in the control strategy module as follows: The control module first acquires the real-time value of the DC-side bus voltage through the acquisition module and compares it with the set target voltage value to calculate the voltage deviation. Then, the voltage error is proportionally and integrally calculated by the PI controller in the voltage outer loop, and a reference value signal for the input current is output. Next, the effective value of the acquired three-phase input current is compared with the reference value, and the PI controller in the current inner loop is adjusted to generate a modulation control signal.

[0071] To enhance the adaptability of this PI structure to grid disturbances, a voltage feedforward channel is introduced into the modulation path. Based on real-time monitoring of the grid voltage phase and amplitude, it compensates for potential input current distortions in advance, thereby improving the speed and stability of current control. Finally, this control signal is input to the PWM modulation unit to drive the switching of the power devices inside the VIENNA rectifier, realizing the rectification control of the three-phase AC input.

[0072] Although the current embodiment does not employ the state prediction capability of model predictive control and the robust compensation mechanism of sliding mode control, it still constitutes a complete control chain from state information acquisition and modulation control command generation to power conversion execution to a certain extent, and can achieve the response to the basic modulation control target of the rectifier.

[0073] However, compared to the preferred embodiment of the present invention, the scheme has several performance disadvantages. First, since the PI regulation structure is a linear control method, it has a slow response speed and limited control accuracy when facing nonlinear dynamic problems such as load changes, grid disturbances, or midpoint voltage deviation. Second, the scheme does not integrate a feedback regulation mechanism for the midpoint potential in the control strategy, and compensation is required through an external voltage equalization loop, making it difficult to guarantee the overall midpoint voltage stability of the system. Third, traditional PI control is difficult to coordinate the synergy between multiple objective control requirements (such as THD suppression, power factor optimization, and voltage stability), and cannot achieve the comprehensive cost function optimization modulation process constructed in the preferred embodiment of the present invention.

[0074] Therefore, the optional embodiments are suitable for low-to-medium power charging scenarios with low control accuracy requirements, sensitive structural costs, or limited hardware resources. However, in situations where high dynamic performance and multi-objective coordinated control are required, the composite control strategy described in the preferred embodiments of the present invention is more suitable.

[0075] S4. Based on modulation control commands, while executing switching control, the DC side midpoint potential of the power conversion unit is synchronously adjusted to control the distribution of DC bus capacitor voltage.

[0076] A disturbance observer is constructed based on the deviation between the measured value of the midpoint potential and the desired equilibrium point to estimate the equivalent disturbance that causes the potential imbalance.

[0077] A voltage equalization adjustment signal is generated based on the disturbance amount, and the adjustment signal is superimposed on the original modulation control command. In the superposition control, a combination of redundant small vectors or zero vectors with midpoint adjustment capability is adopted to change the midpoint current injection path.

[0078] By allocating the duration of different vector actions within the modulation period, the charge balance of the positive and negative bus capacitors on the DC side is adjusted.

[0079] In a preferred embodiment of the present invention, synchronous adjustment of the DC-side midpoint potential of the power conversion unit is performed as follows:

[0080] Maintaining DC-side midpoint potential balance is crucial for the stable and efficient operation of a three-level VIENNA rectifier, as it involves maintaining the voltage balance of the two series-connected bus capacitors on the DC side (i.e., midpoint potential balance). This invention specifically incorporates a midpoint potential balancing module. During VIENNA rectifier operation, this module implements a dynamic voltage equalization algorithm to monitor and actively adjust the midpoint current distribution of the three-level topology in real time. This effectively eliminates midpoint potential shifts caused by factors such as asymmetrical three-phase grid voltages, sudden load changes, or inconsistent power device parameters, thereby ensuring the stability and symmetry of the DC bus voltage. This step complements the DC voltage stability objective, jointly guaranteeing high-quality output power.

[0081] A dynamic voltage equalization algorithm that adjusts the midpoint current in a three-level topology in real time to maintain midpoint potential balance can be specifically a smart voltage equalization algorithm based on a disturbance observer. This algorithm estimates the equivalent disturbance that causes midpoint potential imbalance by constructing a disturbance observer and generates a compensation control signal accordingly. Alternatively, it can be a voltage equalization algorithm based on redundant switch state selection. That is, in modulation strategies such as SVPWM, certain redundant small vectors or zero vectors with the same output line voltage but different effects on the midpoint current are used to actively adjust the injection or outflow of midpoint charge. In addition, it can also be a voltage equalization algorithm based on injecting a zero-sequence voltage component with a specific amplitude and phase into the modulation signal.

[0082] The integration method of the midpoint potential balancing module. The function of the midpoint potential balancing module is preferably deeply integrated with the power switching device drive control logic of the VIENNA rectifier main circuit. Specifically, the midpoint potential balancing control command directly acts on the PWM modulator. By fine-tuning the duty cycle or switching trigger timing of the two active switching devices on each phase bridge arm, or adjusting the duration of different switching states, precise control of the current flowing into or out of the DC bus midpoint is achieved, thereby achieving dynamic balance of the midpoint potential. This integration method has a fast response speed and requires no additional power balancing circuit.

[0083] In one optional embodiment of the present invention, synchronous adjustment of the DC-side midpoint potential of the power conversion unit is as follows:

[0084] The DC-side midpoint-to-ground voltage is sampled at fixed time intervals by the status information acquisition module to calculate the current midpoint potential deviation and compare it with a set voltage deviation threshold. When the deviation exceeds the threshold, the control strategy module triggers a "voltage equalization adjustment cycle." During this cycle, a bias switching mode for a specific duration is forcibly applied to one or two phase arms of the power conversion unit. This can be achieved by simultaneously turning on the upper and lower arms for a short period or applying unequal duty cycles to manually adjust the charging state difference of the positive and negative bus capacitors, thereby restoring the midpoint potential towards the set reference direction.

[0085] To prevent this adjustment behavior from interfering with the main power control task, the control strategy module temporarily suppresses the main modulation task (i.e., freezes or linearly scales the original modulation signal) during the entire adjustment cycle, and then resumes normal PWM modulation operation after the voltage equalization adjustment is completed.

[0086] The current approach still constitutes a closed-loop path of "acquisition → judgment → control → execution" within the system framework of this invention, and does not require the introduction of complex real-time disturbance observers or vector modulation mapping units, making it suitable for application environments with limited hardware resources or those that need to maintain a traditional driver architecture.

[0087] S5. Identify the current operating condition based on the status information, switch to the control template corresponding to the operating condition in the control strategy module, and regenerate the modulation control command.

[0088] Receive charging parameter information and obtain the target charging mode instruction for the current charging stage;

[0089] Analyze the real-time voltage waveform and frequency information of the input power grid to identify whether there is voltage distortion, drop or frequency deviation;

[0090] Based on the charging parameter information and the power grid status information, select the corresponding control template from the preset control strategy template library and load the control parameter structure of the selected template;

[0091] The control target setpoint is recalculated to match the current operating conditions, and modulation control commands are generated in combination with the status information.

[0092] After identifying changes in operating conditions, the modulation parameter output of the previous control template is maintained for several control cycles, and the state variables and control targets in the target control template are initialized synchronously.

[0093] Based on the difference between the target reference values ​​between the two control templates, a modulation transition curve is constructed, and the modulation control command is gradually and smoothly adjusted within a preset transition period.

[0094] The power conversion unit is controlled to respond cycle by cycle by updating the modulation control command, so as to complete the seamless switching of the working mode on the physical control path.

[0095] Example 2 is the second embodiment of the present invention, which provides a core module for a smart charging pile based on the VIENNA structure and a power quality management method. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through experiments.

[0096] Through the above description of Method A (this invention) and Method B (prior art), it is clear that the two differ fundamentally in their technical approaches, core components, control concepts, and the final technical effects they achieve. A direct comparison will follow to further highlight the innovativeness of this invention and its significant beneficial effects.

[0097] Core topology: Method A uses a three-level VIENNA rectifier, integrating AC / DC conversion and main harmonic suppression functions into a single topology; Method B relies on a traditional two-level rectifier and has an external active power filter (APF).

[0098] Harmonic mitigation mechanisms: Method A uses the low harmonic characteristics of the VIENNA topology itself and advanced control algorithms to actively shape and control the input current waveform at its source; Method B, on the other hand, uses an APF to generate a compensation current after harmonics are generated for "end-of-pipe mitigation".

[0099] Core control strategies: Method A adopts a composite adaptive control strategy based on model predictive control (MPC) and adaptive sliding mode control (SMC), emphasizing multi-objective collaborative optimization and strong adaptability to nonlinear and time-varying systems; Method B mostly adopts a linear control strategy based on PI controllers, with each part of the control being relatively independent.

[0100] System integration and complexity: Method A is a highly integrated integrated design scheme, which significantly simplifies the system hardware configuration; Method B is a functionally discrete combination scheme, with a complex system structure and a large number of components.

[0101] Optimization goals and concepts: Method A pursues global synergistic optimization of multiple goals such as power conversion efficiency, harmonic suppression, power factor, DC voltage quality, and neutral point potential balance; Method B is usually a local optimization or simple coordination of each functional unit (rectification, filtering), lacking overall consideration at the system level.

[0102] Table 1. Comparison of Features

[0103]

[0104]

[0105] A comparison of the key issues addressed and a summary of the beneficial effects:

[0106] As can be seen from the comparison in the table above, Method A of the present invention exhibits significant advantages over the prior art Method B in almost all key performance indicators. This is not a simple functional addition or local improvement, but rather stems from a reconstruction at the system architecture level and an innovation in control concepts. Traditional Method B can be regarded as a physical superposition of "rectification function" and "filtering function," while Method A of the present invention is a "system reconstruction" of the entire power conversion and power quality management system. This reconstruction enables the system to exhibit "emergent performance" that is not available through single component optimization or simple functional superposition.

[0107] It is particularly worth emphasizing the comprehensive efficiency evaluation formula proposed in this invention:

[0108] η = η conv ·(1-k THDi ·THDi)·(1-k Vripple ·V ripple ).

[0109] Where, η conv Here, THDi represents the traditional power conversion efficiency, THDi is the total harmonic distortion rate of the input current, Vripple is the DC bus voltage ripple rate, and kTHDi and kVripple are the corresponding compensation factors. The strategic significance of this formula lies in its internalization of power quality indicators (such as harmonics and ripple) into an evaluation of the system's overall "effective output" capability. Traditional scheme B, even with its simple conversion efficiency η... conv While acceptable, its overall efficiency η is inevitably significantly affected because it is usually accompanied by a high THDi (when APF compensation is not ideal) or requires an additional APF to reduce THDi (APF itself has losses). The method of this invention, through VIENNA topology and advanced control, not only strives for a higher η... conv More importantly, it achieves extremely low THDi and excellent Vripple control. Therefore, even in some extreme cases, η conv Compared to traditional methods (and in fact, often even higher due to integration and device advantages), the overall efficiency η of this invention will also be significantly better than that of traditional methods. This formula provides a more comprehensive and scientific quantitative benchmark for evaluating and comparing the true effectiveness of different power quality management solutions, perfectly matching the core theme of this invention, "Power Quality Management Method," and theoretically proving that integrated design can still achieve an improvement in overall efficiency by improving power quality indicators after eliminating the inherent losses of independent active filters.

[0110] In summary, the technical solution of this invention, through the deep integration of topology reconstruction and advanced control algorithms, not only effectively overcomes many bottlenecks of existing technical solutions in terms of harmonic suppression, dynamic response, system efficiency, cost and volume, but also shows great potential in terms of intelligence, grid adaptability and future functional expansion (such as V2G), providing an efficient, compact, intelligent and economical innovative solution for the field of smart charging piles.

[0111] Example 3 is the third embodiment of the present invention, which differs from the previous two embodiments in that:

[0112] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0113] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0114] More specific examples of computer-readable media (a non-exhaustive list) include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0115] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0116] Example 4 is the fourth embodiment of the present invention. This embodiment provides a core module for a smart charging pile based on the VIENNA structure and a power quality management system, including a power conversion execution module, a status information acquisition module, a control strategy module, and a pattern recognition and scheduling module.

[0117] The power conversion execution module receives modulation control commands and drives the switching action of the power conversion unit. Based on the three-level VIENNA rectifier topology, it realizes the energy conversion of three-phase AC to DC. During the energy conversion process, it synchronously adjusts the DC side midpoint potential according to the control commands to control the dynamic balance of the positive and negative capacitor voltages of the DC bus, thereby achieving stable control of the midpoint offset.

[0118] The status information acquisition module collects key electrical parameters during system operation, including input three-phase voltage and current, total harmonic distortion, DC output voltage, current and neutral-to-ground voltage. The collected status information characterizes grid fluctuations, power quality status and the degree of balance in the power conversion process, and serves as real-time feedback input for the control strategy module.

[0119] The control strategy module receives state information input, executes a composite control logic of model predictive control and adaptive sliding mode control, constructs an objective function based on the predictive model, and generates modulation control reference quantities through rolling optimization.

[0120] The pattern recognition and scheduling module receives charging stage parameters and grid operation status information output by the battery management system, identifies the current operating condition, selects the corresponding template from the preset control strategy template library according to the operating condition type, and performs control parameter initialization and smooth transition calculation of reference target quantity after the template is loaded. It works with the control strategy module to complete the continuous switching of working mode and real-time update of control commands.

[0121] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A core module for a smart charging pile based on the VIENNA structure and a method for power quality management, characterized in that: include, An integrated power conversion unit is constructed, which adopts the VIENNA rectifier topology to convert three-phase AC power into DC power, and is equipped with a harmonic suppression structure linked to the control interface. Collect status information during operation and use it as input to the control strategy module; Based on the state information, modulation control commands are generated in the control strategy module to drive the switching action of the power conversion unit. Based on modulation control commands, while executing switching control, the DC side midpoint potential of the power conversion unit is synchronously adjusted to control the distribution of DC bus capacitor voltage. Based on the status information, the current operating condition is identified, and the control strategy module switches to the control template corresponding to the operating condition, and the modulation control command is regenerated.

2. The core module of a smart charging pile based on the VIENNA structure and the power quality management method as described in claim 1, characterized in that: An integrated power conversion unit is constructed, which adopts a VIENNA rectifier topology to convert three-phase AC power into DC power, and includes a harmonic suppression structure linked to the control interface. Configure the input inductor to limit the rate of rise of the input current and form a continuous current path; By setting up series-connected positive and negative bus capacitors, a three-level output structure is formed, creating a node interface for DC midpoint adjustment. The power conversion unit is modulated and controlled using a three-level space vector pulse width modulation method. Based on the modulation command output by the control strategy module, the input AC current is dynamically shaped.

3. The core module of a smart charging pile based on the VIENNA structure and the power quality management method as described in claim 2, characterized in that: The collected status information during the operation process will be used as input to the control strategy module, including: The effective values ​​and phase information of the three-phase voltage and three-phase current on the input side are obtained to determine the power factor relationship between the input current and voltage. Monitor the total harmonic distortion rate of the input current and extract the amplitude information of several specific harmonic components; The instantaneous values ​​of the DC bus voltage and the neutral point-to-ground voltage are obtained, and the voltage ripple amplitude is calculated for use in neutral point potential regulation and control.

4. The core module of a smart charging pile based on the VIENNA structure and the power quality management method as described in claim 3, characterized in that: The process of generating modulation control commands in the control strategy module based on state information to drive the switching action of the power conversion unit includes: In the control strategy module, a prediction structure based on a discrete state-space model is constructed to predict the changing trends of input current, voltage, and bus voltage over multiple future sampling periods. Based on the error between the prediction results and the reference command, an objective function is defined and online rolling optimization is performed to generate the modulation reference quantity for the current cycle. Based on the modulation reference value, a sliding mode surface function and a reaching law are constructed, and the output value of the control command is dynamically corrected according to the actual control error change rate. The modified control commands are mapped to power conversion unit switching control quantities to adjust the modulation duty cycle of each phase bridge arm of the rectifier.

5. The core module of a smart charging pile based on the VIENNA structure and the power quality management method as described in claim 4, characterized in that: The method based on modulation control commands, while executing switching control, synchronously adjusts the DC-side midpoint potential of the power conversion unit to control the distribution of the DC bus capacitor voltage, including: A disturbance observer is constructed based on the deviation between the measured value of the midpoint potential and the desired equilibrium point to estimate the equivalent disturbance that causes the potential imbalance. A voltage equalization adjustment signal is generated based on the disturbance amount, and the adjustment signal is superimposed on the original modulation control command. In the superposition control, a combination of redundant small vectors or zero vectors with midpoint adjustment capability is adopted to change the midpoint current injection path. By allocating the duration of different vector actions within the modulation period, the charge balance of the positive and negative bus capacitors on the DC side is adjusted.

6. The core module of a smart charging pile based on the VIENNA structure and the power quality management method as described in claim 5, characterized in that: The step of identifying the current operating condition based on status information, switching to the control template corresponding to the operating condition in the control strategy module, and regenerating the modulation control command includes: Receive charging parameter information and obtain the target charging mode instruction for the current charging stage; Analyze the real-time voltage waveform and frequency information of the input power grid to identify whether there is voltage distortion, drop or frequency deviation; Based on the charging parameter information and the power grid status information, select the corresponding control template from the preset control strategy template library and load the control parameter structure of the selected template; The control target setpoint is recalculated to match the current operating conditions, and modulation control commands are generated in combination with the status information.

7. The core module of a smart charging pile based on the VIENNA structure and the power quality management method as described in claim 6, characterized in that: The regenerated modulation control command includes After identifying changes in operating conditions, the modulation parameter output of the previous control template is maintained for several control cycles, and the state variables and control targets in the target control template are initialized synchronously. Based on the difference between the target reference values ​​between the two control templates, a modulation transition curve is constructed, and the modulation control command is gradually and smoothly adjusted within a preset transition period. The power conversion unit is controlled to respond cycle by cycle by updating the modulation control command, so as to complete the seamless switching of the working mode on the physical control path.

8. A core module for a smart charging pile based on a VIENNA structure and a power quality management system, employing the core module for a smart charging pile based on a VIENNA structure and the power quality management method as described in any one of claims 1 to 7, characterized in that, It includes: a power conversion execution module, a status information acquisition module, a control strategy module, and a pattern recognition and scheduling module. The power conversion execution module receives modulation control commands and drives the switching action of the power conversion unit. Based on the three-level VIENNA rectifier topology, it realizes the energy conversion of three-phase AC to DC. During the energy conversion process, it synchronously adjusts the DC side midpoint potential according to the control commands to control the dynamic balance of the positive and negative capacitor voltages of the DC bus, thereby achieving stable control of the midpoint offset. The status information acquisition module collects key electrical parameters during system operation, including input three-phase voltage and current, total harmonic distortion, DC output voltage, current and neutral-to-ground voltage. The collected status information characterizes grid fluctuations, power quality status and the degree of balance in the power conversion process, and serves as real-time feedback input for the control strategy module. The control strategy module receives state information input, executes a composite control logic of model predictive control and adaptive sliding mode control, constructs an objective function based on the predictive model, and generates modulation control reference quantities through rolling optimization. The pattern recognition and scheduling module receives charging stage parameters and grid operation status information output by the battery management system, identifies the current operating condition, selects the corresponding template from the preset control strategy template library according to the operating condition type, and performs control parameter initialization and smooth transition calculation of reference target quantity after the template is loaded. It works with the control strategy module to complete the continuous switching of working mode and real-time update of control commands.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the core module of the smart charging pile based on the VIENNA structure and the power quality management method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the core module of the smart charging pile based on the VIENNA structure and the power quality management method as described in any one of claims 1 to 7.

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