Method, apparatus and system for analog control of line impedance dynamics

Abstract

The application provides a kind of line impedance dynamic characteristic simulation control method, device, system and storage medium.The method comprises: initializing virtual line impedance parameter and control parameter;Real-time acquisition of power electronic converter AC side current, and construct resistance, inductive impedance and capacitive impedance characteristic response channel, respectively generate corresponding equivalent voltage response component;According to the reference voltage and each equivalent voltage response component, generate reference voltage, control power electronic converter output, so that its port presents the steady state and transient state characteristic of target line impedance.Inductive impedance dynamic response is obtained according to the AC side current rate of change, and capacitive impedance dynamic response is obtained by capacitive impedance response link with approximate integral characteristic in target AC working frequency band and with limited gain in DC frequency band.The application can realize line impedance dynamic simulation by software algorithm, reduce hardware cost, and improve the flexibility of parameter configuration and simulation control.

Description

Technical Field

[0001] This invention relates to the field of power electronics and power system testing technology, and more particularly to a method, apparatus, system and storage medium for simulating and controlling the dynamic characteristics of line impedance. Background Technology

[0002] In long-distance power transmission with series compensation, the impedance parameters of the transmission line, such as resistance, inductance, and capacitance, significantly impact the operating characteristics of grid-connected equipment. To conduct thorough and realistic grid-connected testing of devices under test (DUTs) such as grid-connected inverters and renewable energy grid-connected equipment in a laboratory environment, it is often necessary to reproduce the external characteristics of the line impedance in a test platform, ensuring that the voltage and current relationships experienced by the DUT at its ports are consistent with when it is connected to a real transmission line. Especially under transient conditions such as grid faults and sudden load changes, the dynamic response performance of the DUT is a key evaluation criterion. This requires the test platform to not only reproduce the external characteristics of the line impedance under steady-state conditions at power frequency but also accurately reproduce the dynamic impedance characteristics of the line during transient processes.

[0003] The existing line impedance simulation schemes mainly include the following: Firstly, there is the circuit impedance simulation scheme based on physical passive components. This scheme directly uses physical passive components such as resistors, inductors, and capacitors to build the equivalent circuit of the circuit impedance. Its drawbacks are: physical passive components are bulky and occupy a large area; the component parameters are fixed once selected, making it difficult to adjust them flexibly in real time during the test, which limits complex test scenarios that require switching different impedance parameters; at the same time, high-power passive components are expensive, further increasing the hardware cost of the test platform.

[0004] Secondly, there is the impedance simulation scheme based on power electronic converters. This scheme utilizes power electronic converters in conjunction with corresponding control algorithms to reproduce the external characteristics of line impedance at the converter ports, thereby replacing some physical passive components. However, this type of scheme often has significant drawbacks in its specific control algorithms: when simulating line inductance characteristics, it is necessary to obtain dynamic response information related to the rate of change of current. Traditional direct differential algorithms are extremely sensitive to noise and easily amplify high-frequency switching noise, thereby compromising the control stability of the system; when simulating line capacitance, it involves the equivalent realization of the integral characteristics of the grid-side current. Traditional pure integral circuits are highly susceptible to the unavoidable DC bias component in the current sampling loop, which can cause integral drift or even integral explosion over time, leading to system malfunction.

[0005] Third, there is the limitation to impedance reproduction schemes based on power frequency steady-state conditions. This scheme often only focuses on reproducing the external impedance characteristics under power frequency steady-state conditions, lacking the ability to accurately simulate the transient processes and dynamic impedance characteristics of the line. Ultimately, this makes it difficult for the test system to reflect the true physical response that the device under test should experience during power grid faults or load changes.

[0006] Therefore, a new solution is needed. Summary of the Invention

[0007] This invention provides a method, device, system, and storage medium for simulating and controlling the dynamic characteristics of line impedance. It addresses the problems of fixed parameters, insufficient adjustment flexibility, and high hardware costs in existing line impedance simulation methods using physical passive devices. It also solves the problems of difficulty in accurately obtaining the dynamic response corresponding to different impedance characteristics in impedance simulation methods based on power electronic converters, and the difficulty in simultaneously reproducing the steady-state and transient dynamic characteristics of line impedance in existing solutions.

[0008] According to a first aspect of the present invention, a method for simulating and controlling the dynamic characteristics of line impedance is provided, the method comprising: Step S1: Initialize the virtual line impedance parameters and control parameters, wherein the virtual line impedance parameters include virtual resistance parameters, virtual inductance parameters and virtual capacitance parameters; Step S2: Real-time acquisition of AC side current of power electronic converter, and construction of resistance characteristic response channel, inductive impedance characteristic response channel and capacitive impedance characteristic response channel based on AC side current; Step S3: Based on the AC side current and the virtual resistance parameter in the virtual line impedance parameters, generate a resistance equivalent voltage response component corresponding to the target line resistance characteristics; Step S4: Obtain the dynamic response of the inductive impedance corresponding to the rate of change of the current based on the AC side current, and generate the inductive equivalent voltage response component corresponding to the inductive characteristics of the target line by combining the virtual inductance parameter in the virtual line impedance parameter. Step S5: Obtain the capacitive impedance dynamic response corresponding to the current integral based on the AC side current, and generate the capacitor equivalent voltage response component corresponding to the target line capacitance characteristics by combining the virtual capacitance parameter in the virtual line impedance parameter. Step S6: Generate a reference voltage based on the base reference voltage and the equivalent voltage response components of the resistor, the equivalent voltage response components of the inductor, and the equivalent voltage response components of the capacitor. Control the output of the power electronic converter according to the reference voltage so that the port of the power electronic converter exhibits the steady-state and transient characteristics of the target line impedance.

[0009] In some embodiments, the virtual line impedance parameters include virtual resistance parameters, virtual inductance parameters, and virtual capacitance parameters; the control parameters include response gain parameters, dynamic compensation parameters, and filter adjustment parameters for adjusting the equivalent response of the resistance, inductance, and capacitance characteristics.

[0010] In some embodiments, the same sampled quantity of the AC side current is input into mutually independent impedance characteristic response channels, which include resistive characteristic response channels, inductive impedance characteristic response channels, and capacitive impedance characteristic response channels, and each response channel generates a corresponding equivalent voltage response component.

[0011] In some embodiments, step S4 includes: Obtain the dynamic response of the inductive impedance corresponding to the rate of change of the AC side current; Based on the inductive impedance dynamic response and the virtual inductance parameters, an inductance equivalent voltage response component corresponding to the inductance characteristics of the target line is generated; wherein, the inductive impedance dynamic response is obtained by state estimation and / or rate of change calculation of the AC side current.

[0012] In some embodiments, obtaining the dynamic response of the inductive impedance includes: performing dynamic state estimation on the AC side current to obtain a response quantity characterizing the current change characteristics; and performing compensation correction based on the dynamic change trend of the response quantity to correct the phase deviation caused by sampling, calculation and control delays, thereby obtaining an inductive impedance dynamic response quantity that matches the inductance characteristics of the target line.

[0013] In some embodiments, step S5 includes: inputting the AC side current into a capacitive impedance response element that has approximately integral characteristics in the target AC operating frequency band and finite gain in the DC frequency band to obtain a capacitive impedance dynamic response quantity; and generating a capacitor equivalent voltage response component corresponding to the target line capacitance characteristics based on the capacitive impedance dynamic response quantity and the virtual capacitor parameters.

[0014] In some embodiments, step S6 includes: Generate a base reference voltage based on preset voltage parameters; A reference voltage for controlling the output of the power electronic converter is generated based on the base reference voltage and the equivalent voltage response components of the resistor, the inductor, and the capacitor.

[0015] According to a second aspect of the present invention, a simulation control device for dynamic characteristics of line impedance is also provided for implementing the method described above, characterized in that it comprises: The initialization module is used to initialize the virtual line impedance parameters and control parameters. The current acquisition module is used to acquire the AC side current of the power electronic converter in real time. The impedance characteristic response generation module is used to generate equivalent voltage response components corresponding to the resistance, inductance, and capacitance characteristics of the target line based on the AC side current. The impedance characteristic response generation module includes: The resistance characteristic response generation unit is used to generate a resistance equivalent voltage response component corresponding to the resistance characteristics of the target line based on the AC side current and the virtual resistance parameter in the virtual line impedance parameter. An inductive impedance response generation unit is used to obtain the dynamic response of inductive impedance based on the AC side current, and to generate an inductive equivalent voltage response component corresponding to the inductive characteristics of the target line based on the virtual inductance parameter in the virtual line impedance parameter. The capacitive impedance response generation unit is used to obtain the capacitive impedance dynamic response quantity through the equivalent integration element based on the AC side current, and to generate the capacitor equivalent voltage response component corresponding to the target line capacitance characteristics based on the virtual capacitance parameter in the virtual line impedance parameter. The control module is used to generate a reference voltage based on the base reference voltage and the equivalent voltage response components of the resistor, the equivalent voltage response components of the inductor, and the equivalent voltage response components of the capacitor, and to control the output of the power electronic converter based on the reference voltage so that the port of the power electronic converter exhibits the target line impedance characteristics.

[0016] According to a third aspect of the present invention, a simulation control system for dynamic characteristics of line impedance is also provided, comprising a memory, a processor, and a computer program stored in the memory and capable of running on the processor; when the processor executes the computer program, it implements the steps of the simulation control method for dynamic characteristics of line impedance as described above.

[0017] According to a fourth aspect of the present invention, a computer-readable storage medium is also provided, on which a computer program is stored, wherein the computer program, when executed by a processor, implements the steps of the simulation control method for the dynamic characteristics of line impedance as described above.

[0018] This invention relates to an equivalent response generation and reconstruction method based on line impedance characteristics. It transforms the impedance characteristics corresponding to line resistance, inductance, and capacitance into adjustable equivalent voltage response components. Through power electronic converter port control, it achieves digital reproduction of the target line impedance characteristics, enabling the port of the device under test to exhibit steady-state and transient impedance characteristics corresponding to the actual line. This invention does not rely on large-capacity physical resistors, inductors, and capacitors; it achieves flexible configuration and dynamic adjustment of line impedance parameters solely through control algorithms. This reduces the hardware complexity and construction cost of the test platform and improves the adaptability to test scenarios under different line impedance conditions. This invention addresses the dynamic response requirements corresponding to different impedance characteristics by constructing corresponding equivalent response generation mechanisms. The inductive impedance response is obtained through dynamic state estimation and compensation correction, while the capacitive impedance response is achieved through an equivalent integral element with integral characteristics. This reduces the impact of noise sensitivity and integral drift issues in traditional differential operations on the accuracy of impedance simulation, improving the accuracy and stability of reproducing the dynamic characteristics of line impedance. This invention employs an impedance characteristic response generation method based on single AC side current sampling to achieve multi-parameter collaborative simulation of resistance, inductance, and capacitance, reducing the need for additional sensors and hardware impedance components, and enhancing the flexibility and scalability of the line impedance simulation system. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort: Figure 1 This is a flowchart illustrating the simulation control method for dynamic characteristics of line impedance provided by the present invention. Figure 2 This is the overall system control block diagram of the simulation control method for dynamic characteristics of line impedance provided by the present invention; Figure 3 This is a detailed signal flow diagram of the simulation control method for dynamic characteristics of line impedance provided by the present invention; Figure 4 This is a schematic diagram of the transient waveforms of the voltages corresponding to the resistor, inductor, and capacitor during load switching provided by the present invention. Figure 5 This is a schematic diagram of the structure of the simulation control device for the dynamic characteristics of line impedance provided by the present invention; Figure 6 This is a schematic diagram of the physical structure of the electronic device provided by the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0021] Existing line impedance simulation technologies either rely on physical passive components, resulting in bulky size and fixed parameters that cannot be adjusted in real time, or when using power electronic converters in conjunction with traditional control algorithms, they suffer from high-frequency switching noise amplification due to pure differential circuits and integral drift and integral explosion due to pure integral circuits, or they are limited to the reproduction of power frequency steady-state external characteristics and lack the ability to simulate transient dynamic characteristics. Generally, it is difficult to accurately reproduce the real physical response of a line during transient changes without relying on bulky physical components.

[0022] To address the aforementioned problems, this invention provides a simulation control method for the dynamic characteristics of line impedance. One implementation scheme is described below with reference to specific embodiments. In this method, the controller initializes virtual line impedance parameters and control parameters; it acquires the AC side current of the power electronic converter in real time, and constructs resistive characteristic response channels, inductive impedance characteristic response channels, and capacitive impedance characteristic response channels based on the same AC side current sampling quantity. The resistive characteristic response channel generates a resistive equivalent voltage response component based on the AC side current and virtual resistance parameters; the inductive impedance characteristic response channel obtains the inductive impedance dynamic response quantity corresponding to the rate of change of current based on the AC side current, and generates an inductive equivalent voltage response component based on virtual inductance parameters; the capacitive impedance characteristic response channel obtains the capacitive impedance dynamic response quantity corresponding to the current integral based on the AC side current, and generates a capacitive equivalent voltage response component based on virtual capacitance parameters. Further, a reference voltage is generated based on the base reference voltage and the aforementioned equivalent voltage response components, and the power electronic converter output is controlled to make its port exhibit the steady-state and transient characteristics of the target line impedance.

[0023] In the description of the embodiments of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. In the description of the embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly defined.

[0024] Figure 1 This is a flowchart illustrating the simulation control method for the dynamic characteristics of line impedance provided by the present invention, as shown below. Figure 1 As shown, the method includes the following steps S1-S6.

[0025] Step S1: Initialize the virtual line impedance parameters and control parameters.

[0026] Specifically, based on the series compensation test scenario simulated according to actual needs, virtual line impedance parameters are preset in the controller. These virtual line impedance parameters include virtual resistance parameters, virtual inductance parameters, and virtual capacitance parameters. In this embodiment, these parameters are represented by virtual resistance value Rvir, virtual inductance value Lvir, and virtual capacitance value Cvir, respectively. In one exemplary implementation, Rvir can be set to 0.8 ohms, Lvir to 4.8 millihenries, and Cvir to 370 microfarads. This invention does not limit the specific values ​​of each virtual line impedance parameter and can flexibly configure them according to the line conditions to be simulated.

[0027] Furthermore, the controller also presets control parameters, including response gain parameters, dynamic compensation parameters, and filter adjustment parameters for adjusting the equivalent response of the resistance, inductance, and capacitance characteristics. In one specific implementation of this embodiment, the dynamic compensation parameters may include the observer bandwidth ω0 of the improved linearly extended state observer and multi-point slope prediction phase lead compensation parameters (e.g., compensation gain K). comp (Slope prediction order M and prediction weight coefficients for each order), filter adjustment parameters may include the cutoff frequency f of the first-order low-pass filter. c Alternatively, the time constant τ can be set, and additionally, basic reference voltage parameters (such as angle θ and voltage amplitude V) can be set. base ).

[0028] It should be noted that since the above-mentioned virtual circuit impedance parameters and control parameters are all preset by the controller in software, each parameter can be flexibly adjusted in real time as needed during the test, thus overcoming the shortcomings of physical passive device parameters being fixed once selected and difficult to adjust in real time.

[0029] Step S2: Real-time acquisition of AC side current of power electronic converter, and construction of resistance characteristic response channel, inductive impedance characteristic response channel and capacitive impedance characteristic response channel based on AC side current.

[0030] Specifically, the system acquires the AC side current of the power electronic converter in real time through an AC side current sensor. In this embodiment, the output current signal i on the grid-connected side of the power electronic converter is used. g The AC side current, hereinafter referred to as the grid-side current, is used as the input information for impedance simulation. This invention only requires the acquisition of the AC side current to obtain the necessary input information for impedance simulation, eliminating the need for additional high-capacity physical impedance components.

[0031] Acquired AC side current signal i gThe same sample value is input to three independent response channels: a resistance response channel, an inductive impedance response channel, and a capacitive impedance response channel. Each response channel generates a corresponding equivalent voltage response component. In this embodiment, the three response channels are implemented as parallel resistance simulation branches, inductance simulation branches, and capacitance simulation branches. Each branch operates independently and in parallel, enabling the synchronous acquisition of the equivalent voltage response components corresponding to the resistance, inductance, and capacitance characteristics within the same control cycle.

[0032] It should be noted that the power electronic converter can be a grid-connected inverter or other types of power electronic conversion devices, and the present invention does not limit its specific topology.

[0033] Step S3: Based on the AC side current and the virtual resistance parameter in the virtual line impedance parameters, generate a resistance equivalent voltage response component corresponding to the target line resistance characteristics.

[0034] Specifically, the resistance characteristic response channel is based on Ohm's law, combining the real-time acquired AC side current signal ig with preset virtual resistance parameters to generate the resistance equivalent voltage response component v. R In this embodiment, the virtual resistance parameter is expressed as the virtual resistance value R. vir This means that, therefore, v R = i g ·R vir The equivalent voltage response component v of the resistor R It can also be called virtual resistance voltage drop.

[0035] Since the resistance characteristic response channel in this embodiment only involves algebraic multiplication of current and virtual resistance value, and does not involve differentiation or integration, the generated resistance equivalent voltage response component v R It can quickly reflect changes in the AC side current waveform. Under transient operating conditions such as load switching, v R It can change synchronously with the change of AC side current.

[0036] Step S4: Obtain the dynamic response of the inductive impedance corresponding to the rate of change of the current based on the AC side current, and generate the inductive equivalent voltage response component corresponding to the inductive characteristics of the target line by combining the virtual inductance parameter in the virtual line impedance parameter.

[0037] Specifically, when simulating the inductive characteristics of a line, it is necessary to obtain the dynamic response of the inductive impedance corresponding to the rate of change of the AC side current, and generate the equivalent voltage response component of the inductance by combining it with preset virtual inductance parameters. The dynamic response of the inductive impedance can be obtained by state estimation and / or rate of change calculation of the AC side current. When it is necessary to correct the phase deviation caused by sampling, calculation, and control delays, compensation and correction can also be performed based on the dynamic trend of the response quantity characterizing the current change.

[0038] In this embodiment, the dynamic response of the inductive impedance is specifically realized through a current rate of change estimate, which is obtained by using a modified linear extended state observer (LESO) to dynamically estimate the AC side current. Compared to the direct differential method, this embodiment obtains the response characteristic representing the current change through state observation, thereby reducing the impact of amplified high-frequency switching noise.

[0039] Furthermore, to compensate for the phase lag caused by the state observation process and digital control delay, this embodiment performs multi-point slope prediction phase advance compensation based on the dynamic change trend of the current change rate estimate, and generates the inductor equivalent voltage response component based on the compensated inductive impedance dynamic response and virtual inductance parameters.

[0040] In some implementations, step S4 further includes the following sub-steps.

[0041] First, the grid-side current ig is input into an improved linear expansion state observer for state observation, and the output is a current estimate and a current differential estimate. Specifically, the grid-side current ig is used as the input to the improved linear expansion state observer, and the state observation is performed according to the discrete form of the improved linear expansion state observer. The output includes a current estimate (denoted as z1) and a current differential estimate (denoted as z). 2raw The state variables are as follows: The differential estimate of the current z. 2raw As a specific implementation of the dynamic response of inductive impedance, it is used to characterize the rate of change of AC current. Compared with the traditional pure differential circuit, the state observation method can obtain the current change rate information while reducing the impact of high-frequency noise amplification.

[0042] Secondly, based on the current differential estimate at the current sampling time and at least one historical sampling time, multi-point slope prediction phase advance compensation is performed to obtain the compensated current differential estimate. Specifically, factors such as observer bandwidth ω0, sampling, calculation, and control delays may affect the current differential estimate z. 2rawTo address the phase deviation, this implementation introduces a point-slope linear compensation (PLC) phase lead compensation algorithm to compensate and correct based on the dynamic change trend of the response quantity.

[0043] The core idea of ​​multi-point slope prediction phase lead compensation is to calculate the dynamic change trend of the current differential estimate at the current sampling time and the historical sampling time, and then extrapolate it linearly forward to compensate for the phase deviation caused by the state estimation and digital control process, so that the obtained dynamic response of inductive impedance matches the inductive characteristics of the target line.

[0044] Let the current discrete sampling time be k, and the sampling period be T. s The original estimate of the current differential term in the LESO observation output is z. 2raw The specific discretization formula for phase lead compensation using multi-point slope prediction is as follows: where, z comp For the process PLC The final output value of the current differential term after phase lead compensation by the algorithm:

[0045] In some implementations, the multi-point slope prediction employs M-order slope prediction, where M is the order of the historical sampling points selected for slope prediction. The value of M can be balanced between compensation accuracy and high-frequency noise suppression; for example, M = 1 or M is a higher order. When using M-order slope prediction, the prediction weight coefficient W of each order of slope can be used... i The prediction weighting coefficient W can be flexibly controlled to adjust the phase lead angle. i The value of W is positively correlated with the observer bandwidth ω0 and the inherent control delay of the system. This can be achieved by adjusting the prediction weight coefficient W. i This allows for flexible control of the phase lead angle.

[0046] Specifically, when using first-order slope prediction (i.e., M=1), the compensation formula can be simplified to a two-point linear extrapolation form. Let the current discrete sampling time be k, and the sampling period be T. s The improved linear extended state observer output current differential estimate is z. 2raw The compensated differential estimate of the current satisfies the following equation:

[0047] Among them, z comp (k) represents the compensated differential estimate of the current; z 2raw (k) represents the differential estimate of the current output at the current sampling time k; z 2raw (k 1) is the previous sampling time k 1. The differential estimate of the output current; K comp To compensate for the gain (i.e., to compensate for the lead gain), the compensation gain K is adjusted. comp The phase lead angle can be flexibly controlled.

[0048] Third, an inductor equivalent voltage response component is generated based on the compensated differential current estimate and the virtual inductance value. Specifically, the compensated differential current estimate z... comp With the preset virtual inductance value L vir By combining these methods, the equivalent voltage response component v of the inductor can be calculated. L (In this embodiment, it is also referred to as virtual inductance voltage drop).

[0049] Through the above compensation calculations, this embodiment can reduce the high-frequency noise sensitivity of the direct differential method while compensating for the phase deviation caused by the delay in state observation, sampling, calculation and control, thereby improving the reproduction effect of the inductor equivalent voltage response component on the dynamic characteristics of the target line inductance.

[0050] To further illustrate its implementation, the pseudocode for the inductor-based analog control logic combining first-order multi-point slope prediction (M=1) with an improved linear extended state observer is given below: Algorithm: Dynamic Simulation and Phase Compensation of Line Inductance Input: Real-time acquired grid-side current i g [k]; Output: Inductor equivalent voltage response component vL[k].

[0051] Initialization (executed once at startup): (1) Initialize the parameters of the improved linear extension state observer: observer bandwidth ω0, virtual inductance value L vir ; (2) Clear the history buffer and improve the internal state buffer of the linear expansion state observer.

[0052] Main loop (executed in the interrupt service routine corresponding to each sampling period Ts): (1) Extract the differential estimate of the current: z 2raw [k] ← LESO(i g [k]); (2) Phase lead compensation: z comp [k] ← z 2raw [k] + K comp ·(z 2raw [k] z 2raw [k 1]); (3) Generation of voltage response components: v L [k] ← L vir ·z comp [k]; (4) State update: z 2raw [k 1] ← z 2raw [k].

[0053] Step S5: Obtain the capacitive impedance dynamic response corresponding to the current integral based on the AC side current, and generate the capacitor equivalent voltage response component corresponding to the target line capacitance characteristics by combining the virtual capacitance parameter in the virtual line impedance parameter.

[0054] Specifically, when simulating the line capacitance characteristics, it is necessary to obtain the dynamic response of the capacitive impedance corresponding to the integral of the AC side current, and generate the equivalent voltage response component of the capacitor by combining it with preset virtual capacitor parameters. In order to take into account both the integral characteristics in the target AC operating frequency band and the stability in the DC frequency band, a capacitive impedance response element that has approximately integral characteristics in the target AC operating frequency band and finite gain in the DC frequency band can be used.

[0055] In this embodiment, a first-order low-pass filter is used to construct the capacitive impedance response circuit to obtain the dynamic response of the capacitive impedance. The capacitive impedance response circuit exhibits an approximate integral characteristic in the target AC operating frequency band and maintains a finite gain in the DC frequency band, thereby achieving an equivalent transformation of the AC side current integral characteristic and suppressing the infinite accumulation of DC bias.

[0056] First, construct the transfer function of the first-order low-pass filter: ; In the formula, s is the Laplace operator, and τ is the time constant of the first-order low-pass filter. The system sets the cutoff frequency f of the first-order low-pass filter. c Set to an extremely low value (e.g., 0.5 Hz), and configure the time constant τ = 1 / (2πf) accordingly. c ).

[0057] In the actual operation logic of the algorithm, when the system operates in the target AC working frequency band (e.g., 50 Hz power frequency) and satisfies τω When the signal is in the DC band, the frequency domain characteristics of the first-order low-pass filter are approximately HLPF(s) ≈ 1 / (τs), thus exhibiting an approximate integral characteristic. When the signal is in the DC band, the gain of the first-order low-pass filter remains at a finite value, thereby avoiding the infinite accumulation of the DC bias signal and reducing the impact of integral drift or integral saturation on the dynamic response of the capacitive impedance.

[0058] Furthermore, based on the capacitive impedance dynamic response and preset virtual capacitance parameters, a capacitor equivalent voltage response component corresponding to the capacitance characteristics of the target line is generated. Specifically, in this embodiment, a gain compensation coefficient G is set after the first-order low-pass filter. comp Based on the capacitive impedance dynamic response and the virtual capacitance parameter C vir Gain compensation is performed to generate the capacitor equivalent voltage response component. In some implementations, the gain compensation coefficient is: ; Where τ is the time constant of the first-order low-pass filter, and C vir This is the virtual capacitance value.

[0059] Specifically, within each control cycle, the controller will collect the AC side current signal i in real time. g The capacitive impedance response circuit is input and processed by a first-order low-pass filter to obtain the capacitive impedance dynamic response. Subsequently, based on the capacitive impedance dynamic response and the virtual capacitance parameter C... vir Through the gain compensation coefficient G comp Gain compensation is performed to generate the capacitor equivalent voltage response component v corresponding to the capacitance characteristics of the target line. C (In this embodiment, it is also referred to as virtual capacitor voltage drop). Its complete signal processing frequency domain mathematical model can be expressed as:

[0060] In this way, the capacitive impedance response circuit approximately exhibits integral characteristics within the target AC operating frequency band and maintains limited gain in the DC frequency band. Under transient conditions such as load switching, the equivalent voltage response component vC of the capacitor can maintain a continuous and smooth transition, and reduce the risk of integral drift caused by DC bias.

[0061] Step S6: Based on the base reference voltage and the equivalent voltage response components of the resistor, the equivalent voltage response components of the inductor, and the equivalent voltage response components of the capacitor, a reference voltage is generated, and the output of the power electronic converter is controlled according to the reference voltage so that the port of the power electronic converter exhibits the steady-state and transient characteristics of the target line impedance.

[0062] Specifically, in some implementations, step S6 further includes the following sub-steps.

[0063] First, a base reference voltage is generated based on preset voltage parameters. Specifically, the system generates the base reference voltage based on preset grid frequency and rated voltage amplitude V. base This generates the corresponding frequency and phase information (e.g., angle θ), and based on this, generates the basic open-loop reference voltage v. base The reference voltage is used to characterize the base voltage of the power grid to which the object under test should be connected.

[0064] Secondly, based on the base reference voltage and the equivalent voltage response components of the resistor, the inductor, and the capacitor, a reference voltage for controlling the output of the power electronic converter is generated. Specifically, in this embodiment, the system uses the base reference voltage v base The equivalent voltage response components (resistive equivalent voltage response component v) calculated from the three response channels R Inductor equivalent voltage response component v L and the equivalent voltage response component of the capacitor v C The final reference voltage command (v) is synthesized on demand. ref This invention does not impose restrictions on the specific synthesis method and symbol conventions of each equivalent voltage response component, which can be determined according to the series impedance relationship and direction convention of the simulated line.

[0065] Subsequently, the reference voltage command v ref The signal is fed into the underlying pulse width modulation (PWM) module, which controls the output of the power electronic converter according to the reference voltage, so that the port of the power electronic converter exhibits the steady-state and transient characteristics of the target line impedance.

[0066] The following is combined Figure 2 An implementation method for the overall system control of the present invention will be described. For example... Figure 2 As shown, the system acquires the AC side current i through an AC side current sensor. g The same sample value is sent to the resistive characteristic response channel, the inductive impedance characteristic response channel, and the capacitive impedance characteristic response channel, respectively. In this specific implementation, the inductive impedance characteristic response channel includes an improved linear expansion state observer and a multi-point slope prediction phase lead compensation module, while the capacitive impedance characteristic response channel includes a first-order low-pass filter and a gain compensation module. The resistive equivalent voltage response component v output by the three response channels is... R Inductor equivalent voltage response component v L and the equivalent voltage response component of the capacitor v C With the base reference voltage v base Synthetic reference voltage v ref Finally, the power electronic converter outputs the signal through a pulse width modulation module.

[0067] The following is combined Figure 3 The overall signal flow of this invention will be explained. For example... Figure 3 As shown, the signal flow of the present invention can be divided into the following three stages: In the signal acquisition and parameter preset stage, the system first acquires the AC side current i of the power electronic converter in real time through the AC side current sensor. gSimultaneously, the controller presets virtual line impedance parameters required for the test scenario, including virtual resistance parameters, virtual inductance parameters, and virtual capacitance parameters, which are respectively represented by R in this embodiment. vir L vir And C vir This indicates that the angle θ and voltage amplitude V used to generate the base reference voltage can also be set. base Parameters such as these.

[0068] During the parallel generation stage of impedance characteristic response, the acquired AC side current signal i g The same sample value is input into three independent response channels: resistive characteristic response channel, inductive impedance characteristic response channel, and capacitive impedance characteristic response channel. Specifically, the inductive impedance characteristic response channel obtains the dynamic response value characterizing the rate of change of current through an improved linear expansion state observer, and performs compensation correction through multi-point slope prediction, combined with the virtual inductance parameter L. vir Generate inductor equivalent voltage response component v L The capacitive impedance characteristic response channel obtains the dynamic response of the capacitive impedance through a capacitive impedance response stage composed of a first-order low-pass filter, and then uses the dynamic response of the capacitive impedance and the virtual capacitance parameter C as the basis for the response. vir Gain compensation is performed to generate the capacitor equivalent voltage response component v. C The resistance characteristic response channel will control the AC side current i g With virtual resistance parameter R vir Combined, the resistive equivalent voltage response component vR is generated.

[0069] In the reference voltage synthesis and output stage, the system generates a base reference voltage v based on preset voltage parameters. base Subsequently, the base reference voltage is compared with the resistance equivalent voltage response component v generated by the three response channels mentioned above. R Inductor equivalent voltage response component v L and the equivalent voltage response component of the capacitor v C On-demand synthesis of reference voltage command v ref The power electronic converter output is controlled according to the reference voltage, so that its port exhibits the steady-state and transient characteristics of the target line impedance.

[0070] The following is combined Figure 4 The transient response performance of a specific embodiment of the present invention is described to verify the simulation effect of transient and steady-state characteristics of line impedance. In an exemplary test scenario, the load of the power electronic converter is switched from 10 ohms to 20 ohms, and R is set at this time. vir = 0.8 ohms, L vir = 4.8 millihenries, C vir = 370 microfarads. Figure 4The resistive equivalent voltage response component v is shown during load switching. R Inductor equivalent voltage response component v L and the equivalent voltage response component of the capacitor v C The waveform.

[0071] according to Figure 4 It can be seen that during the steady-state operation phase, the inductor equivalent voltage response component v in this embodiment... L The equivalent voltage response component of the capacitor, v C Relative to the equivalent voltage response components v of the resistor R It presents a phase relationship corresponding to the characteristics of the target inductance and capacitance; after load switching, the steady-state amplitude of each equivalent voltage response component changes accordingly with the change of AC side current.

[0072] During the transient process of load switching: the resistive equivalent voltage response component v R It responds quickly to changes in AC current; the inductive impedance characteristic response channel obtains the dynamic response of inductive impedance corresponding to the rate of change of current through state estimation and performs compensation and correction to generate the corresponding inductor equivalent voltage response component v. L The capacitive impedance characteristic response channel generates a capacitive equivalent voltage response component v through a response element that has approximately integral characteristics in the target AC operating frequency band and finite gain in the DC frequency band. C This ensures that the transient changes remain continuous and smooth.

[0073] In another exemplary test scenario, the load is switched from 15 ohms to 30 ohms, causing a change in the AC side current amplitude. Correspondingly, the resistive equivalent voltage response component v... R The inductor's equivalent voltage response component v adjusts with changes in current. L The transient response corresponding to the rate of change of current, and the equivalent voltage response component of the capacitor, v. C The waveform results demonstrate the dynamic response corresponding to the current integral. These results further show that this embodiment can simultaneously reproduce the steady-state and transient characteristics of the target line impedance.

[0074] The following describes the simulation control device for the dynamic characteristics of line impedance provided by the present invention. The device described below and the method described above can be referred to in correspondence.

[0075] Figure 5 This is a schematic diagram of the structure of the simulation control device for the dynamic characteristics of line impedance provided by the present invention. Figure 5 As shown, the device includes an initialization module 510, a current acquisition module 520, an impedance characteristic response generation module 530, and a control module 540. The impedance characteristic response generation module 530 includes a resistance characteristic response generation unit 531, an inductive impedance response generation unit 532, and a capacitive impedance response generation unit 533.

[0076] Initialization module 510 is used to initialize virtual line impedance parameters and control parameters; The current acquisition module 520 is used to acquire the AC side current of the power electronic converter in real time. Impedance characteristic response generation module 530 is used to generate equivalent voltage response components corresponding to the resistance, inductance and capacitance characteristics of the target line according to the AC side current. The resistance characteristic response generation unit 531 is used to generate a resistance equivalent voltage response component corresponding to the resistance characteristics of the target line based on the AC side current and the virtual resistance parameter in the virtual line impedance parameter. The inductive impedance response generation unit 532 is used to obtain the dynamic response of inductive impedance based on the AC side current, and generate an inductive equivalent voltage response component corresponding to the inductive characteristics of the target line based on the virtual inductance parameter in the virtual line impedance parameter. The capacitive impedance response generation unit 533 is used to obtain the capacitive impedance dynamic response quantity through the equivalent integration link based on the AC side current, and to generate the capacitor equivalent voltage response component corresponding to the target line capacitor characteristics based on the virtual capacitor parameters in the virtual line impedance parameters. The control module 540 is used to generate a reference voltage based on the base reference voltage and the equivalent voltage response components of the resistor, the equivalent voltage response components of the inductor, and the equivalent voltage response components of the capacitor, and to control the output of the power electronic converter based on the reference voltage so that the port of the power electronic converter presents the target line impedance characteristics.

[0077] In one specific implementation, the three response generation units in the impedance characteristic response generation module 530 can be respectively implemented as a resistance simulation branch, an inductance simulation branch, and a capacitance simulation branch, and receive the same sample quantity of the AC side current; the initialization module 510 can also set response gain parameters, dynamic compensation parameters, filter adjustment parameters, and basic reference voltage parameters.

[0078] In one specific implementation, the inductive impedance response generation unit 532 can perform dynamic state estimation by inputting the AC side current into the improved linear expansion state observer, output the current differential estimate, and perform multi-point slope prediction phase lead compensation based on the dynamic change trend of the current differential estimate to obtain the compensated inductive impedance dynamic response quantity, and then combine it with the virtual inductance value to generate the inductance equivalent voltage response component.

[0079] In one specific implementation, the capacitive impedance response generation unit 533 can use a first-order low-pass filter to construct a capacitive impedance response loop with approximate integral characteristics in the target AC operating frequency band and finite gain in the DC frequency band, so as to obtain the capacitive impedance dynamic response quantity; and generate the capacitor equivalent voltage response component by gain compensation based on the capacitive impedance dynamic response quantity and the virtual capacitance value.

[0080] Figure 6 An example of an electronic device physical structure for implementing the dynamic characteristics of line impedance in the present invention is provided. For instance... Figure 6 As shown, the electronic device may include a processor 610, a communications interface 620, a memory 630, and a communication bus 640, wherein the processor 610, the communications interface 620, and the memory 630 communicate with each other via the communication bus 640. The memory 630 may store a computer program that can run on the processor 610; when the processor 610 executes the computer program, it implements the simulation control method for the dynamic characteristics of line impedance as described in the above embodiments of the present invention. Taking the method corresponding to claim 1 as an example, it may include: Step S1: Initialize the virtual line impedance parameters and control parameters, wherein the virtual line impedance parameters include virtual resistance parameters, virtual inductance parameters and virtual capacitance parameters; Step S2: Real-time acquisition of AC side current of power electronic converter, and construction of resistance characteristic response channel, inductive impedance characteristic response channel and capacitive impedance characteristic response channel based on AC side current; Step S3: Based on the AC side current and the virtual resistance parameter in the virtual line impedance parameters, generate a resistance equivalent voltage response component corresponding to the target line resistance characteristics; Step S4: Obtain the dynamic response of the inductive impedance corresponding to the rate of change of the current based on the AC side current, and generate the inductive equivalent voltage response component corresponding to the inductive characteristics of the target line by combining the virtual inductance parameter in the virtual line impedance parameter. Step S5: Obtain the capacitive impedance dynamic response corresponding to the current integral based on the AC side current, and generate the capacitor equivalent voltage response component corresponding to the target line capacitance characteristics by combining the virtual capacitance parameter in the virtual line impedance parameter. Step S6: Generate a reference voltage based on the base reference voltage and the equivalent voltage response components of the resistor, the equivalent voltage response components of the inductor, and the equivalent voltage response components of the capacitor. Control the output of the power electronic converter according to the reference voltage so that the port of the power electronic converter exhibits the steady-state and transient characteristics of the target line impedance.

[0081] Furthermore, the logic instructions in the aforementioned memory 630 can be implemented as software functional units and used as independent software products, and can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention can be implemented through a computer-readable storage medium storing a computer program, which, when executed by a processor, can implement the aforementioned analog control method for dynamic characteristics of line impedance. The storage medium may include a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, or other media capable of storing program code.

[0082] In one alternative implementation of the software product, the computer program may be stored on a non-transitory computer-readable storage medium and, when executed by a processor, cause the computer to perform the above-described simulation control method for the dynamic characteristics of line impedance; this implementation does not affect the technical scope of the above-described computer-readable storage medium embodiments.

[0083] In another aspect, the present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the above-mentioned simulation control method for dynamic characteristics of line impedance.

[0084] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0085] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A simulation control method for the dynamic characteristics of line impedance, characterized in that, include: Step S1: Initialize the virtual line impedance parameters and control parameters, wherein the virtual line impedance parameters include virtual resistance parameters, virtual inductance parameters and virtual capacitance parameters; Step S2: Real-time acquisition of AC side current of power electronic converter, and construction of resistance characteristic response channel, inductive impedance characteristic response channel and capacitive impedance characteristic response channel based on AC side current; Step S3: Based on the AC side current and the virtual resistance parameter in the virtual line impedance parameters, generate the resistance equivalent voltage response component corresponding to the target line resistance characteristics; Step S4: Obtain the dynamic response of the inductive impedance corresponding to the rate of change of the current based on the AC side current, and generate the inductive equivalent voltage response component corresponding to the inductive characteristics of the target line by combining the virtual inductance parameter in the virtual line impedance parameter. Step S5: Obtain the capacitive impedance dynamic response corresponding to the current integral based on the AC side current, and generate the capacitor equivalent voltage response component corresponding to the target line capacitance characteristics by combining the virtual capacitance parameter in the virtual line impedance parameter. Step S6: Generate a reference voltage based on the base reference voltage and the equivalent voltage response components of the resistor, the equivalent voltage response components of the inductor, and the equivalent voltage response components of the capacitor. Control the output of the power electronic converter according to the reference voltage so that the port of the power electronic converter exhibits the steady-state and transient characteristics of the target line impedance.

2. The method according to claim 1, characterized in that, The virtual line impedance parameters include virtual resistance parameters, virtual inductance parameters, and virtual capacitance parameters; the control parameters include response gain parameters, dynamic compensation parameters, and filter adjustment parameters used to adjust the equivalent response of the resistance, inductance, and capacitance characteristics.

3. The method according to claim 1, characterized in that, The same sampled value of the AC side current is input into independent impedance characteristic response channels, including resistive impedance characteristic response channel, inductive impedance characteristic response channel and capacitive impedance characteristic response channel, and each response channel generates a corresponding equivalent voltage response component.

4. The method according to claim 1, characterized in that, Step S4 includes: Obtain the dynamic response of the inductive impedance corresponding to the rate of change of the AC side current; Based on the inductive impedance dynamic response and the virtual inductance parameters, an inductance equivalent voltage response component corresponding to the inductance characteristics of the target line is generated; wherein, the inductive impedance dynamic response is obtained by state estimation and / or rate of change calculation of the AC side current.

5. The method according to claim 4, characterized in that, The acquisition of the dynamic response of the inductive impedance includes: performing dynamic state estimation on the AC side current to obtain a response quantity characterizing the current change characteristics; and performing compensation and correction based on the dynamic change trend of the response quantity to correct the phase deviation caused by sampling, calculation and control delays, thereby obtaining an inductive impedance dynamic response quantity that matches the inductive characteristics of the target line.

6. The method according to claim 1, characterized in that, Step S5 includes: inputting the AC side current into a capacitive impedance response element that has approximately integral characteristics in the target AC operating frequency band and finite gain in the DC frequency band to obtain a capacitive impedance dynamic response quantity; and generating a capacitor equivalent voltage response component corresponding to the target line capacitance characteristics based on the capacitive impedance dynamic response quantity and the virtual capacitor parameters.

7. The method according to claim 1, characterized in that, Step S6 includes: Generate a base reference voltage based on preset voltage parameters; A reference voltage for controlling the output of the power electronic converter is generated based on the base reference voltage and the equivalent voltage response components of the resistor, the inductor, and the capacitor.

8. A simulation control device for the dynamic characteristics of line impedance, used to implement the method according to any one of claims 1 to 7, characterized in that, include: The initialization module is used to initialize the virtual line impedance parameters and control parameters. The current acquisition module is used to acquire the AC side current of the power electronic converter in real time. The impedance characteristic response generation module is used to generate equivalent voltage response components corresponding to the resistance, inductance, and capacitance characteristics of the target line based on the AC side current. The impedance characteristic response generation module includes: The resistance characteristic response generation unit is used to generate a resistance equivalent voltage response component corresponding to the resistance characteristics of the target line based on the AC side current and the virtual resistance parameter in the virtual line impedance parameter. An inductive impedance response generation unit is used to obtain the dynamic response of inductive impedance based on the AC side current, and to generate an inductive equivalent voltage response component corresponding to the inductive characteristics of the target line based on the virtual inductance parameter in the virtual line impedance parameter. The capacitive impedance response generation unit is used to obtain the capacitive impedance dynamic response quantity through the equivalent integration element based on the AC side current, and to generate the capacitor equivalent voltage response component corresponding to the target line capacitance characteristics based on the virtual capacitance parameter in the virtual line impedance parameter. The control module is used to generate a reference voltage based on the base reference voltage and the equivalent voltage response components of the resistor, the equivalent voltage response components of the inductor, and the equivalent voltage response components of the capacitor, and to control the output of the power electronic converter based on the reference voltage so that the port of the power electronic converter exhibits the target line impedance characteristics.

9. A simulation control system for the dynamic characteristics of line impedance, characterized in that, Includes a memory, a processor, and a computer program stored in the memory and capable of running on the processor; When the processor executes the computer program, it implements the steps of the simulation control method for the dynamic characteristics of line impedance as described in 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 simulation control method for the dynamic characteristics of line impedance as described in any one of claims 1 to 7.

Images