Ripple component extraction method, ripple signal suppression method, ripple component extraction device, and power equipment

Abstract

This application discloses a method for ripple component extraction, a method for ripple signal suppression, a device for ripple component extraction, and power equipment. The method includes: inputting a target bus voltage signal and an instantaneous angular frequency into an SOGI filter for processing, so that the SOGI filter outputs an instantaneous in-phase component and an instantaneous quadrature component; controlling a PI controller based on an instantaneous feedback quantity to perform closed-loop control of the instantaneous angular frequency; and when the instantaneous angular frequency converges to the target angular frequency, the SOGI filter outputs the instantaneous in-phase component of the target angular frequency. This application uses a software approach to extract ripple components, eliminating the need for additional hardware circuitry, which is beneficial for miniaturizing the energy storage system and reducing hardware costs. The instantaneous feedback quantity provides the PI controller with the tracking direction and magnitude of the true angular frequency of the ripple component, ensuring that the instantaneous angular frequency output by the PI controller converges accurately and reliably to the target angular frequency, thereby adaptively extracting the ripple component to be solved.

Description

Technical Field

[0001] This application relates to the field of power equipment technology, and in particular to a ripple component extraction method, a ripple signal suppression method, a ripple component extraction device, and power equipment. Background Technology

[0002] Energy storage systems consist of DC-DC converters and power conversion systems (PCS). The high-voltage bus of the DC-DC converter is susceptible to the operating conditions of the power conversion system, easily generating ripple components. The frequency of these ripple components varies with the load type and grid frequency, severely impacting the control performance of the energy storage system. Related technologies extract the ripple component from the bus voltage signal using a bandpass filter circuit, and then extract the DC component based on the ripple component and the bus voltage signal. However, this approach requires additional hardware circuitry, increasing system size and cost, and has low reliability, making it difficult to meet the stable operation requirements of high-performance energy storage systems. Summary of the Invention

[0003] One objective of this application is to provide a ripple component extraction method, a ripple signal suppression method, a ripple component extraction device, and a power equipment, thereby improving the situation where the system size and cost are too large due to the need to add hardware circuits to extract ripple components in related technologies.

[0004] In a first aspect, embodiments of this application provide a method for extracting ripple components, comprising: acquiring a target bus voltage signal, the target bus voltage signal including a ripple component to be solved; inputting the target bus voltage signal and the instantaneous angular frequency output by the PI controller of the target loop to the SOGI filter of the target loop for processing, so that the SOGI filter outputs an instantaneous in-phase component and an instantaneous quadrature component, the initial instantaneous angular frequency being a preset value; controlling the PI controller to perform closed-loop control of the instantaneous angular frequency fed back to the SOGI filter based on the instantaneous feedback quantity, so that the instantaneous angular frequency converges to the target angular frequency, the instantaneous feedback quantity being determined based on the instantaneous error between the instantaneous quadrature component and the SOGI filter, the instantaneous error being the difference between the ripple component to be solved and the instantaneous in-phase component; when the instantaneous angular frequency converges to the target angular frequency, the SOGI filter outputs the instantaneous in-phase component of the target angular frequency based on the target angular frequency fed back by the PI controller.

[0005] Optionally, the PI controller is controlled to perform closed-loop control of the instantaneous angular frequency fed back to the SOGI filter based on the instantaneous feedback quantity, including: determining the proportional term at the current moment based on the product of the instantaneous feedback quantity and the proportional coefficient; determining the integral term at the current moment based on the cumulative feedback value and the integral coefficient; the cumulative feedback value is the sum of all instantaneous feedback quantities from the initial moment to the current moment; and determining the instantaneous angular frequency of the PI controller at the current moment based on the sum of the instantaneous angular frequency, the proportional term, and the integral term at the initial moment.

[0006] Optionally, the target bus voltage signal and the instantaneous angular frequency output by the PI controller of the target loop are input to the SOGI filter of the target loop for processing, so that the SOGI filter outputs an instantaneous in-phase component, including: determining the first in-phase resonant component of the sine waveform based on the instantaneous angular frequency output by the PI controller and the amplitude of the ripple component to be solved; determining the instantaneous correction amplitude based on the instantaneous difference of the angular frequency and the amplitude of the ripple component to be solved, wherein the instantaneous difference of the angular frequency is the difference between the target angular frequency and the instantaneous angular frequency; determining the first in-phase correction component of the cosine waveform based on the instantaneous angular frequency output by the PI controller and the instantaneous correction amplitude; and determining the instantaneous in-phase component based on the sum of the first in-phase resonant component and the first in-phase correction component.

[0007] Optionally, the target bus voltage signal and the instantaneous angular frequency output by the PI controller of the target loop are input to the SOGI filter of the target loop for processing, so that the SOGI filter outputs an instantaneous quadrature component, including: determining the second in-phase resonant component of the cosine waveform based on the instantaneous angular frequency output by the PI controller and the amplitude of the ripple component to be solved; determining the instantaneous correction amplitude based on the instantaneous difference of angular frequencies and the amplitude of the ripple component to be solved, wherein the instantaneous difference of angular frequencies is the difference between the target angular frequency and the instantaneous angular frequency; determining the first quadrature correction component of the sine waveform based on the instantaneous angular frequency output by the PI controller and the instantaneous correction amplitude; and determining the instantaneous quadrature component based on the difference between the second in-phase resonant component and the first quadrature correction component.

[0008] Optionally, determining the instantaneous correction amplitude based on the instantaneous difference of angular frequency and the amplitude of the ripple component to be solved includes: determining the first product result of the instantaneous difference of angular frequency and the amplitude of the ripple component to be solved; determining the second product result of the preset damping coefficient of the state equation of the instantaneous angular frequency output by the PI controller and the output result of the SOGI filter at each moment; and determining the instantaneous correction amplitude at each moment based on the quotient of the first product result and the second product result.

[0009] Optionally, the instantaneous feedback quantity is determined based on the instantaneous quadrature component and the instantaneous error of the SOGI filter, and is: the instantaneous feedback quantity is the product of the instantaneous quadrature component and the instantaneous error of the SOGI filter.

[0010] In a second aspect, embodiments of this application provide a ripple signal suppression method, comprising: acquiring an original bus voltage signal; performing high-frequency noise filtering on the original bus voltage signal using a preset low-pass filter to obtain a target bus voltage signal; extracting the ripple component of the target bus voltage signal using the aforementioned ripple component extraction method; and determining the DC component in the original bus voltage signal based on the difference between the target bus voltage signal and the ripple component.

[0011] In a third aspect, embodiments of this application provide a ripple component extraction device, including a signal acquisition module and an SOGI filter module and a closed-loop control module that interact and constitute a target loop. The signal acquisition module is used to acquire a target bus voltage signal, which includes a ripple component to be solved. The SOGI filter module is used to output an instantaneous in-phase component and an instantaneous quadrature component based on the target bus voltage signal and the instantaneous angular frequency output by the closed-loop control module. The closed-loop control module is used to perform closed-loop control of the instantaneous angular frequency fed back to the SOGI filter module based on the instantaneous feedback quantity, so that the instantaneous angular frequency converges to the target angular frequency. The instantaneous feedback quantity is determined based on the instantaneous error between the instantaneous quadrature component and the SOGI filter. The instantaneous error is the difference between the ripple component to be solved and the instantaneous in-phase component. When the instantaneous angular frequency output by the PI controller converges to the target angular frequency, the SOGI filter module outputs an instantaneous in-phase component of the target angular frequency based on the target angular frequency fed back by the PI controller.

[0012] In a fourth aspect, embodiments of this application provide a power device including a memory and a processor. The memory is connected to the processor, and the processor is used to execute one or more computer programs stored in the memory. When the processor executes one or more computer programs, it causes the power device to implement the above-described ripple component extraction method or the above-described ripple signal suppression method.

[0013] In a fifth aspect, embodiments of this application provide a computer-readable storage medium storing a computer program, the computer program including program instructions, which, when executed by a processor, cause the processor to perform the above-described ripple component extraction method or the above-described ripple signal suppression method.

[0014] The embodiments of this application achieve the following technical effects: The embodiments of this application use software to extract ripple components, eliminating the need for additional hardware circuitry, which facilitates the miniaturization of the energy storage system and reduces hardware costs. Simultaneously, the embodiments of this application construct instantaneous feedback quantities based on instantaneous orthogonal components and instantaneous errors. These instantaneous feedback quantities provide the PI controller with the tracking direction and magnitude of the true angular frequency of the ripple components, enabling the instantaneous angular frequency output by the PI controller to accurately and reliably converge adaptively to the target angular frequency. The SOGI filter, based on the target angular frequency fed back by the PI controller, outputs an instantaneous in-phase component consistent with the ripple components, thereby adaptively completing the extraction or reconstruction of the ripple components to be solved. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A schematic diagram of the system architecture of an energy storage system provided in this application embodiment;

[0017] Figure 2 A flowchart illustrating a ripple component extraction method provided in an embodiment of this application;

[0018] Figure 3 An SOGI filter provided in this application embodiment Bode plot of the function;

[0019] Figure 4 An SOGI filter provided in this application embodiment Bode plot of the function;

[0020] Figure 5 A waveform diagram of a raw bus voltage signal provided for an embodiment of this application;

[0021] Figure 6 A waveform diagram illustrating the acquisition of the DC component provided in an embodiment of this application;

[0022] Figure 7 A flowchart illustrating a ripple signal suppression method provided in an embodiment of this application;

[0023] Figure 8 This is a schematic diagram of the structure of a ripple component extraction device provided in an embodiment of this application;

[0024] Figure 9This is a schematic diagram of the structure of a ripple signal suppression device provided in an embodiment of this application;

[0025] Figure 10 This is a schematic diagram of the structure of a power device provided in an embodiment of this application. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0027] It should be noted that, unless there is a conflict, the various features in the embodiments of this application can be combined with each other, all of which are within the protection scope of this application. Furthermore, although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than the module division in the device or the order in the flowchart. Moreover, the terms "first," "second," and "third" used in this application do not limit the data or execution order, but only distinguish identical or similar items with essentially the same function and effect.

[0028] Energy storage systems consist of DC-DC converters and energy storage inverters. Bus voltage control is one of the key technologies to ensure the stable operation of energy storage systems. When the energy storage inverter operates at different frequencies and under different loads, ripple components will be introduced into the bus, which will seriously affect the control performance of the DC-DC converter of the energy storage system.

[0029] The generation mechanism of ripple components is closely related to the operating mode of the energy storage converter. When the energy storage converter is operating with a full-wave load, the frequency of the ripple component is twice the power frequency of the energy storage converter. For example, when the energy storage converter operates at 50Hz, the bus voltage will generate a 100Hz ripple component. When the energy storage converter is operating with a half-wave load, the frequency of the ripple component is the same as the power frequency of the energy storage converter. More complexly, the operating frequency of the energy storage converter is not fixed; it may operate at different frequencies such as 50Hz or 60Hz depending on the power grid standards of different regions, making the frequency characteristics of the ripple component uncertain. Furthermore, other types of harmonic interference exist in the energy storage system, further exacerbating the fluctuations in the bus voltage.

[0030] The main method for suppressing ripple in related technologies is through hardware-based filtering of ripple components. As mentioned earlier, this technique suppresses ripple components by increasing the capacity of the bus filter capacitor. However, this approach has significant limitations: on the one hand, large-capacity bus capacitors significantly increase the system's size, weight, and cost; on the other hand, the limited lifespan of the bus capacitors reduces the system's reliability.

[0031] Therefore, this application adopts a software filtering method, using a second-order generalized integrator (SOGI) to adaptively track the instantaneous angular frequency of the ripple component. Based on the tracked instantaneous angular frequency, a signal consistent with the ripple component is reconstructed, thereby completing the extraction of the ripple component. Then, the extracted ripple component is subtracted from the target bus voltage signal to obtain the DC component. This approach can effectively suppress the ripple component of the target bus voltage signal without hardware modifications, thereby obtaining a relatively accurate and reliable DC component.

[0032] The following embodiments of this application provide an energy storage system. Please refer to... Figure 1 The energy storage system 100 includes a battery pack 11, a DC-DC converter 12, a DC bus 13, a bus capacitor 14, an energy storage converter 15, a voltage detection circuit 16, and a microcontroller 17.

[0033] Battery pack 11 is used to provide power or store power.

[0034] The DC-DC converter 12 is electrically connected to the battery pack 11 and is used to boost or buck the power supplied by the battery pack 11. Alternatively, it can receive the power transmitted by the energy storage converter 15 and boost or buck the power transmitted by the energy storage converter 15 to obtain boosted or bucked power, and then transmit the boosted or bucked power to the battery pack 11 for storage.

[0035] The DC bus 13 is electrically connected between the DC-DC converter 12 and the energy storage converter 15, and the bus capacitor 14 is also electrically connected to the DC bus 13. The DC bus 13 is used to transmit the DC bus voltage.

[0036] The bus capacitor 14 stores energy based on the DC bus voltage and applies voltage to the energy storage converter 15.

[0037] The energy storage converter 15 can rectify the AC power from the grid into DC power, which is then transmitted to the DC-DC converter 12 via the DC bus 13. The DC-DC converter 12 performs step-up and step-down processing on the DC power to obtain processed DC power, which is then transmitted to the battery pack 11 for storage. Alternatively, the energy storage converter 15 can also invert the DC bus voltage based on the DC bus voltage of the bus capacitor 14 into AC power, which is then transmitted to the load to drive the load.

[0038] The voltage detection circuit 16 is electrically connected to the DC bus 13 and is used to sample the original bus voltage signal. The voltage detection circuit 16 can be a circuit with voltage sampling function composed of a single resistor or a resistor network, or it can be a voltage sensor or an ADC sampling circuit, etc.

[0039] The microcontroller 17 is electrically connected to the DC-DC converter 12, the energy storage converter 15, and the voltage detection circuit 16, respectively. It processes the original bus voltage signal according to the ripple component extraction method or ripple signal suppression method described in the various embodiments below, in order to suppress the ripple component and obtain a reliable and accurate DC component. Then, based on the feedback of the DC component, the microcontroller 17 can reliably and accurately control the operating state of the DC-DC converter 12 or the energy storage converter 15, which is beneficial to the reliable and safe operation of the energy storage system 100.

[0040] To explain in detail the extraction principle of ripple components provided in the embodiments of this application, please refer to the following. Figure 2 This application provides a method for extracting ripple components, which extracts ripple components through steps S21 to S24, as detailed below:

[0041] Step S21: Obtain the target bus voltage signal, which includes the ripple component to be solved.

[0042] The target bus voltage signal is composed of a DC component and a ripple component to be solved. As mentioned earlier, the voltage detection circuit performs voltage sampling on the DC bus to obtain the original bus voltage signal. This original bus voltage signal is the bus voltage signal before filtering. The original bus voltage signal contains not only the DC component and the ripple component to be solved, but also random high-frequency noise.

[0043] In this embodiment, the original bus voltage signal is set as follows: Original bus voltage signal The expression is shown in Formula 1:

[0044] Formula 1

[0045] Where k is the sampling time, It is a pure DC component. For ripple components, It is random high-frequency noise.

[0046] In this application embodiment, Formula 2 is used as the mathematical expression for the ripple component, as shown below:

[0047] Formula 2

[0048] If the influence of harmonic order is not considered, the mathematical expression of the ripple component in this embodiment is updated to the mathematical expression of the fundamental component, as shown in Formula 3:

[0049] Formula 3

[0050] in, Where N is the sampling period, N is the total harmonic order, and n is the harmonic order. Let n be the amplitude of the nth harmonic. The initial phase of the nth harmonic. Let ω be the angular frequency of the fundamental component, and A be the amplitude of the fundamental component.

[0051] The mathematical expression for the angular frequency of the fundamental component is: , The frequency of the fundamental component is 50Hz or 60Hz, depending on the operating mode of the energy storage converter. The corresponding full-wave frequencies are 100Hz or 120Hz, respectively.

[0052] The value of N is typically in the range of 1 to 5, which can cover the main interference components that have a significant impact on the DC component. It can be understood that in the target bus voltage signal, the fundamental component is the dominant component with the largest amplitude, the highest energy, and the most serious impact on control. The harmonic components of the second harmonic, third harmonic, and higher orders have a relatively weak impact on the DC component. Therefore, the embodiments of this application mainly focus on the extraction of the fundamental component, that is: the ripple component extracted in the embodiments of this application is actually the fundamental component.

[0053] The embodiments of this application can use hardware filtering or software digital filtering to perform high-frequency filtering on the original bus voltage signal, thereby obtaining the target bus voltage signal.

[0054] In some embodiments, the energy storage system further includes a low-pass filter circuit. In the embodiments of the present application, the original bus voltage signal is input into the low-pass filter circuit, so that the low-pass filter circuit filters high-frequency noise from the original bus voltage signal, filters out the random high-frequency noise included in the original bus voltage signal, and thus obtains the target bus voltage signal. The cut-off frequency of the low-pass filter circuit is greater than the highest frequency of the ripple component. Exemplarily, the cut-off frequency is 1 kHz, and the highest frequency of the ripple component is 300 Hz. When the cut-off frequency of the low-pass filter circuit is set to 1 kHz, the low-pass filter circuit can effectively filter out random high-frequency noise, but will not attenuate the ripple component, and maximally retains the characteristic information of the ripple component, so that the complete ripple component can be reconstructed in subsequent steps, which is beneficial to obtaining an accurate and reliable DC component.

[0055] In some other embodiments, in the embodiments of the present application, a first-order infinite impulse response low-pass filter (First-Order Infinite Impulse Response Low-Pass Filter, First-Order IIR LPF) is used to filter high-frequency noise from the original bus voltage signal, filter out the random high-frequency noise included in the original bus voltage signal, and thus obtain the target bus voltage signal.

[0056] The discrete-domain transfer function of the first-order infinite impulse response low-pass filter is as shown in Formula Four:

[0057] Formula Four

[0058] Among them, the mathematical expression of the filtering coefficient a is as shown in Formula Five:

[0059] Formula Five

[0060] Among them, is the cut-off frequency, and the filtering coefficient a satisfies the condition of 0 < a < 1 to ensure the stability of the first-order infinite impulse response low-pass filter. In practical applications, the sampling frequency is usually set to more than 100 times the frequency of the ripple component to ensure sufficient sampling accuracy.

[0061] The mathematical expression of the difference equation of the first-order infinite impulse response low-pass filter is as shown in Formula Six:

[0062] Formula Six

[0063] is the target bus voltage signal at the k-th sampling moment, is the original bus voltage signal at the k-th sampling moment, This is the target bus voltage signal at time k-1.

[0064] As shown in Formula 6, the first-order infinite impulse response low-pass filter performs recursive iterative calculations to weight and fuse the original bus voltage signal at the k-th sampling time (i.e., the current bus sampling signal) with the target bus voltage signal at the (k-1)-th sampling time (i.e., the historical filtered output signal), effectively reducing the instantaneous fluctuations of random high-frequency noise, while preserving the low-frequency ripple component and DC component to the greatest extent.

[0065] After the original bus voltage signal is filtered by high-frequency noise, the target bus voltage signal can be approximately expressed as:

[0066] Formula 7

[0067] By combining Equations 1 and 7, we can see that: random high-frequency noise It is significantly attenuated, while the DC component and ripple components It was completely preserved.

[0068] Step S22: Input the target bus voltage signal and the instantaneous angular frequency output by the PI controller of the target loop to the SOGI filter of the target loop for processing, so that the SOGI filter outputs instantaneous in-phase components and instantaneous quadrature components, and the instantaneous angular frequency at the initial moment is a preset value.

[0069] The target loop is a loop that tracks the angular frequency of the ripple component to be solved in order to reconstruct the ripple component. The target loop includes an SOGI (Second-Order Generalized Integrator) filter and a PI controller (Proportional-Integral Controller).

[0070] The SOGI filter is a signal processing structure specifically designed for bandpass filtering and orthogonalization of periodic signals. It has advantages such as simple structure, convenient parameter design, and good frequency selectivity. In the embodiments of this application, the SOGI filter can not only extract the instantaneous orthogonal component with the same frequency as the ripple component, but also track the frequency change of the ripple component through an adaptive control mechanism, and output a component with the same frequency and phase as the ripple component.

[0071] The transfer function of the SOGI filter is:

[0072] Formula 8

[0073] Formula Nine

[0074] The function is the transfer function of the instantaneous in-phase component, which can output the component that is in phase and frequency with the ripple component to be solved. The function is the transfer function of the instantaneous orthogonal component, which can output a component that has the same frequency as the ripple component to be solved but is 90° out of phase.

[0075] When the frequency is 50Hz, the frequency domain response of the SOGI filter is plotted using a Bode plot, where, Bode plot of the function as follows Figure 3 As shown, Bode plot of the function as follows Figure 4 As shown.

[0076] like Figure 3 and Figure 4 As shown, when the frequency of the ripple component to be solved is 50Hz, the SOGI filter can track and output a signal that is in phase and frequency with the ripple component to be solved (equivalent to extracting the ripple component), and can also output a signal that is in phase and frequency with the ripple component to be solved but 90° out of phase.

[0077] As mentioned earlier, the operating frequency of the energy storage converter is not fixed; it operates at different frequencies, such as 50Hz and 60Hz, depending on the power grid standards of different regions. This results in uncertainty in the frequency characteristics of the ripple component. When the frequency of the changed ripple component deviates significantly from 50Hz, and the SOGI filter still filters at 50Hz, the frequency of the changed ripple component falls within... Bode plot of the function and The fast decay region of the Bode plot of the function, combined with Figure 3 It can be seen that the frequency of the changed ripple component deviates significantly from 50Hz. The Bode plot of the function shows a significant drop in amplitude and a severe phase deviation from 0°, making it impossible to track the output signal that is consistent with or close to the changed ripple component. Combined with... Figure 4 It can also be seen that, The amplitude of the Bode plot of the function decays rapidly to 0, and the phase deviates significantly from -90°, making it impossible to generate an instantaneous orthogonal component that matches the changed ripple component.

[0078] In this embodiment of the application, when the frequency of the changed ripple component deviates significantly from 50Hz, the PI controller continuously corrects the deviation, so that the SOGI filter can still track and output a signal that is consistent with or close to the changed ripple component, which is equivalent to being able to extract the changed ripple component.

[0079] The continuous-domain state equation of the SOGI filter is:

[0080] Formula 10

[0081] Formula Eleven

[0082] in, The ripple component (i.e., the fundamental component) to be solved after high-frequency noise filtering is given. To be the instantaneous in-phase component that is in phase and has the same frequency as the ripple component to be solved, To be an instantaneous orthogonal component that has the same frequency as the ripple component to be solved but lags behind it by 90° in phase, Here, k is the estimated angular frequency (i.e., the instantaneous angular frequency), and k is the preset damping coefficient. Typically, k = 2. , =0.707, in order to ensure system stability and fast response.

[0083] After the original bus voltage signal is filtered by high-frequency noise, the ripple component to be solved is obtained. The pure fundamental component is expressed mathematically as shown in Formula XII:

[0084] Formula 12

[0085] Where A is the amplitude of the ripple component to be solved. For the initial phase, Let be the true angular frequency (i.e., the target angular frequency) of the ripple component to be solved, where .

[0086] This concludes the introduction to the architecture and mathematical expression of the SOGI filter. It can be understood that the SOGI filter here can be a hardware circuit built from various logic devices to form a SOGI filtering function, or a software module that can implement the SOGI filtering function.

[0087] The PI controller tracks the true angular frequency of the ripple component in real time, based on the error between the ripple component to be solved and the instantaneous in-phase component tracked by the SOGI filter. This allows the angular frequency output by the PI controller to gradually converge to the true angular frequency of the ripple component. The PI controller and the SOGI filter work together to form a target loop with negative feedback closed-loop control, adaptively tracking the true angular frequency of the ripple component, enabling the SOGI filter to output an in-phase component consistent with the ripple component.

[0088] A PI controller consists of a proportional term and an integral term. The proportional term responds quickly to errors and rapidly adjusts the estimated angular frequency, while the integral term continuously corrects accumulated errors, eliminating static errors and ensuring that the estimated angular frequency is closely approximated or matches the true angular frequency. It can be understood that the PI controller here can be a hardware circuit with PI control functionality built from various logic devices, or a software module capable of implementing PI control.

[0089] The instantaneous angular frequency is the estimated angular frequency output by the PI controller after performing a frequency tracking operation at each time step. For example, after the PI controller performs a frequency tracking operation at time k, it obtains the estimated angular frequency at time k. The estimated angular frequency at time k Let be the instantaneous angular frequency at time k. After the PI controller performs frequency tracking operation at time k+1, it obtains the estimated angular frequency at time k+1. The estimated angular frequency at time k+1 Let be the instantaneous angular frequency at time k+1. And so on, without further explanation.

[0090] The instantaneous in-phase component is the in-phase component output by the SOGI filter after performing the filtering operation at each time step, and the instantaneous quadrature component is the quadrature component output by the SOGI filter after performing the filtering operation at each time step. For example, after performing the filtering operation at time k, the SOGI filter produces the in-phase component at time k. Orthogonal components at time k The SOGI filter performs the filtering operation at time k+1, and obtains the in-phase component at time k+1. Orthogonal components at time k+1 And so on, without going into detail here.

[0091] As shown in Formula 7, the target bus voltage signal contains both a DC component and a ripple component. When the SOGI filter receives the target bus voltage signal and the instantaneous angular frequency output by the PI controller, since both the frequency and angular frequency of the DC component are 0, and the SOGI filter's... functions and All functions are second-order resonant bandpass transfer functions. The bandpass characteristic determines that the SOGI filter only has a resonant amplification effect on the frequency of the ripple component, exhibiting strong attenuation characteristics for the DC component and high-frequency harmonics. Therefore, the DC component will be suppressed by the SOGI filter, while the ripple component will pass. The SOGI filter will not output the DC component and will output the ripple component to be solved. Perform filtering.

[0092] The SOGI filter outputs instantaneous in-phase and instantaneous quadrature components based on the target bus voltage signal and the instantaneous angular frequency output by the PI controller. The initial instantaneous angular frequency is a preset value; that is, when the target loop begins tracking the true angular frequency of the ripple component to be solved, the PI controller defaults to using the preset value as the initial instantaneous angular frequency and feeds it back to the SOGI filter.

[0093] The preset value can be customized by the designer based on engineering experience. In some embodiments, the preset value is associated with the power frequency of the energy storage system. For example, the power frequency of the energy storage converter is 100Hz or 120Hz, and the true angular frequency (i.e., the target angular frequency) of the ripple component to be solved usually fluctuates around the angular frequency corresponding to 50Hz or 60Hz. The energy storage system calculates the angular frequency corresponding to 50Hz or 60Hz and feeds it back to the SOGI filter as the preset value. The PI controller does not need to perform many convergence steps and can quickly converge the instantaneous angular frequency to the target angular frequency. This also enables the SOGI filter to quickly output an instantaneous in-phase component with the same frequency as the ripple component to be solved, quickly completing the extraction of the ripple component to be solved. This helps improve the extraction efficiency of the ripple component to be solved, helps the energy storage system quickly suppress the ripple component, and obtains an accurate and reliable DC component for implementing a reliable control strategy.

[0094] Step S23: Control the PI controller to perform closed-loop control of the instantaneous angular frequency fed back to the SOGI filter based on the instantaneous feedback quantity, so that the instantaneous angular frequency converges to the target angular frequency.

[0095] The instantaneous feedback quantity serves as the input to the PI controller, driving the instantaneous angular frequency output by the PI controller to converge to the target angular frequency. The instantaneous feedback quantity is determined based on the instantaneous quadrature component and the instantaneous error of the SOGI filter, where the instantaneous error is the difference between the ripple component to be solved and the instantaneous in-phase component.

[0096] The mathematical expression for instantaneous error is:

[0097] Formula Thirteen

[0098] in, For instantaneous error, Let be the ripple component to be solved. It is an instantaneous in-phase component.

[0099] In some embodiments, the instantaneous feedback quantity is the product of the instantaneous quadrature component and the instantaneous error of the SOGI filter. Specifically, the mathematical expression for the instantaneous feedback quantity is:

[0100] Formula Fourteen

[0101] in, For instantaneous feedback quantity, These are instantaneous orthogonal components.

[0102] instantaneous error This reflects the difference between the ripple component to be solved and the instantaneous in-phase component, but when the instantaneous angular frequency is not equal to the target angular frequency, the instantaneous error... It is actually a high-frequency AC signal, and high-frequency AC signals have positive and negative half-cycles.

[0103] If instantaneous error Inconsistent instantaneous orthogonal components When multiplying, the integral term of the PI controller cannot effectively cancel the error corresponding to the AC signal. Therefore, in this case, although the proportional term of the PI controller can convert the instantaneous angular frequency... Closer to the true angular frequency The difference exists, but as mentioned above, the integral term cannot effectively cancel out the error corresponding to the high-frequency AC signal. Therefore, the final result is: the instantaneous angular frequency output by the PI controller. It can never converge to the true angular frequency. This causes the instantaneous angular frequency output by the PI controller to... At true angular frequency It fluctuates repeatedly in the vicinity.

[0104] If instantaneous error and instantaneous orthogonal components Multiplication actually results in the instantaneous error being multiplied. The signal conversion process results in a DC signal for the instantaneous feedback quantity obtained by multiplication. Since there are no positive or negative half-cycles, the integral term of the PI controller continuously accumulates the error based on this instantaneous feedback. Then, leveraging the rapid adjustment of the proportional term, the instantaneous angular frequency output by the PI controller is determined. It can converge to the true angular frequency. Therefore, the instantaneous feedback provides the PI controller with the tracking direction and magnitude of the true angular frequency of the ripple component, thus enabling the PI controller to output the instantaneous angular frequency. It can accurately and reliably adaptively converge to the true angular frequency. This is beneficial for improving the extraction accuracy of ripple components.

[0105] Step S24: When the instantaneous angular frequency converges to the target angular frequency, the SOGI filter outputs the instantaneous angular frequency as the instantaneous in-phase component of the target angular frequency based on the target angular frequency fed back by the PI controller.

[0106] The target angular frequency is the true angular frequency of the ripple component to be solved, and the instantaneous angular frequency is the instantaneous in-phase component of the target angular frequency, which is the component that is consistent with the ripple component to be solved. When the SOGI filter outputs the instantaneous in-phase component of the target angular frequency based on the target angular frequency fed back by the PI controller, the SOGI filter has extracted or reconstructed the ripple component.

[0107] This application embodiment uses software to extract ripple components, eliminating the need for additional hardware circuitry. This facilitates the miniaturization of the energy storage system and reduces hardware costs. Furthermore, this application embodiment constructs an instantaneous feedback quantity based on instantaneous orthogonal components and instantaneous errors. This instantaneous feedback quantity provides the PI controller with the tracking direction and magnitude of the true angular frequency of the ripple components, enabling the instantaneous angular frequency output by the PI controller to accurately and reliably converge adaptively to the target angular frequency. The SOGI filter, based on the target angular frequency fed back by the PI controller, outputs an instantaneous in-phase component consistent with the ripple components, thereby adaptively completing the extraction or reconstruction of the ripple components to be solved.

[0108] Regardless of the type of ripple component encountered in the embodiments of this application, the embodiments of this application can adaptively track the target angular frequency of the ripple component and reconstruct an instantaneous in-phase component consistent with the ripple component based on the target angular frequency of the ripple component. Therefore, the ripple component extraction method provided by the embodiments of this application has strong compatibility and robustness.

[0109] As mentioned above, the SOGI filter can output an instantaneous in-phase component based on the target bus voltage signal and the instantaneous angular frequency output by the PI controller. Specifically, in this embodiment, steps S221 to S224 control the SOGI filter to output the instantaneous in-phase component, as shown below:

[0110] Step S221: Based on the instantaneous angular frequency output by the PI controller and the amplitude of the ripple component to be solved, determine the first in-phase resonant component of the sine waveform.

[0111] For example, in this embodiment of the application, the first in-phase resonant component is output according to Formula Fifteen, as shown below:

[0112] Formula Fifteen

[0113] in, This is the first in-phase resonant component. Let be the amplitude of the ripple component to be solved. The instantaneous angular frequency output by the PI controller. This is the initial phase.

[0114] Step S222: Determine the instantaneous correction amplitude based on the instantaneous difference of angular frequency and the amplitude of the ripple component to be solved.

[0115] The instantaneous angular frequency difference is the difference between the target angular frequency (i.e., the true angular frequency of the ripple component to be solved) and the instantaneous angular frequency. In this embodiment, an amplitude conversion can be performed based on the instantaneous angular frequency difference and the amplitude of the ripple component to be solved, thereby obtaining the instantaneous corrected amplitude.

[0116] Determining the instantaneous correction amplitude based on the instantaneous difference of angular frequency and the amplitude of the target bus voltage signal includes the following steps: determining the first product result of the instantaneous difference of angular frequency and the amplitude of the ripple component to be solved; determining the second product result of the state equation of the instantaneous angular frequency output by the PI controller and the output result of the SOGI filter at each moment and the preset damping coefficient; and determining the instantaneous correction amplitude at each moment based on the quotient of the first product result and the second product result.

[0117] Specifically, this application embodiment illustrates the process of obtaining the instantaneous correction amplitude using Formula Sixteen, as shown below:

[0118] Formula Sixteen

[0119] in, For instantaneous correction amplitude, Let be the amplitude of the ripple component to be solved. This represents the instantaneous difference in angular frequency. This is the preset damping coefficient.

[0120] Step S223: Based on the instantaneous angular frequency and instantaneous correction amplitude output by the PI controller, determine the first in-phase correction component of the cosine waveform.

[0121] Specifically, a mathematical expression for the first in-phase correction component in this application embodiment is as follows:

[0122] Formula 17

[0123] in, This is the first in-phase correction component.

[0124] Step S224: Determine the instantaneous in-phase component based on the sum of the first in-phase resonant component and the first in-phase correction component.

[0125] Specifically, a mathematical expression for the instantaneous in-phase component in this application embodiment is as follows:

[0126] Formula 18

[0127] in, It is an instantaneous in-phase component.

[0128] At this point, the instantaneous angular frequency output by the PI controller... Not equal to the target angular frequency At that time, the mathematical expression of the SOGI filter with respect to the instantaneous in-phase component is shown in Formula 18.

[0129] As shown in Formula 18, when the PI controller continuously feeds back the instantaneous angular frequency... The SOGI filter is based on formula eighteen, combined with instantaneous angular frequency. It continuously tracks and outputs the instantaneous in-phase component at each moment. The instantaneous angular frequency fed back by the PI controller... It has converged to the target angular frequency. At that time, instantaneous difference of angular frequency The first in-phase correction component is 0, and the instantaneous in-phase component output by the SOGI filter is... That is, the mathematical construction of the instantaneous in-phase component output by the SOGI filter is consistent with the mathematical construction of the ripple component to be solved. This is equivalent to the SOGI filter having extracted or reconstructed a signal consistent with the ripple component to be solved.

[0130] As mentioned above, the SOGI filter can output instantaneous quadrature components based on the target bus voltage signal and the instantaneous angular frequency output by the PI controller. Specifically, in this embodiment, steps S225 to S228 control the SOGI filter to output instantaneous quadrature components, as shown below:

[0131] Step S225: Based on the instantaneous angular frequency output by the PI controller and the amplitude of the ripple component to be solved, determine the second in-phase resonant component of the cosine waveform.

[0132] For example, in this embodiment of the application, the second in-phase resonant component is output according to Formula Nineteen, as shown below:

[0133] Formula 19

[0134] in, This is the second in-phase resonant component.

[0135] Step S226: Determine the instantaneous correction amplitude based on the instantaneous difference of angular frequency and the amplitude of the ripple component to be solved.

[0136] The instantaneous angular frequency difference is the difference between the target angular frequency (i.e., the true angular frequency of the ripple component to be solved) and the instantaneous angular frequency. In this embodiment, an amplitude conversion can be performed based on the instantaneous angular frequency difference and the amplitude of the ripple component to be solved, thereby obtaining the instantaneous corrected amplitude.

[0137] Determining the instantaneous correction amplitude based on the instantaneous difference of angular frequency and the amplitude of the target bus voltage signal includes the following steps: determining the first product result of the instantaneous difference of angular frequency and the amplitude of the ripple component to be solved; determining the second product result of the state equation of the instantaneous angular frequency output by the PI controller and the output result of the SOGI filter at each moment and the preset damping coefficient; and determining the instantaneous correction amplitude at each moment based on the quotient of the first product result and the second product result.

[0138] Step S227: Based on the instantaneous angular frequency and instantaneous correction amplitude output by the PI controller, determine the first orthogonal correction component of the sine waveform.

[0139] Specifically, a mathematical expression for the first orthogonal correction component in this application embodiment is as follows:

[0140] Formula 20

[0141] in, This is the first orthogonal correction component; the instantaneous correction amplitude is... .

[0142] Step S228: Determine the instantaneous quadrature component based on the difference between the second in-phase resonant component and the first quadrature correction component.

[0143] Specifically, a mathematical expression for the instantaneous in-phase component in this application embodiment is as follows:

[0144] Formula 21

[0145] in, These are instantaneous orthogonal components.

[0146] At this point, the instantaneous angular frequency output by the PI controller... Not equal to the target angular frequency At that time, the mathematical expression of the SOGI filter with respect to the instantaneous orthogonal components is shown in Equation 21.

[0147] As shown in Formula 21, when the PI controller continuously feeds back the instantaneous angular frequency... The SOGI filter is based on formula twenty-one, combined with instantaneous angular frequency. It continuously tracks and outputs the instantaneous quadrature component at each moment. The instantaneous angular frequency fed back by the PI controller... It has converged to the target angular frequency. At that time, instantaneous difference of angular frequency The first orthogonal correction component is 0, and the instantaneous orthogonal component output by the SOGI filter is... That is, the instantaneous quadrature component of the SOGI filter output lags behind the phase of the ripple component to be solved by 90°.

[0148] In this embodiment, the SOGI filter is configured according to the mathematical expressions of Formula 18 and Formula 21. When the PI controller continuously feeds back the instantaneous angular frequency... The SOGI filter is based on the instantaneous angular frequency. It continuously tracks and outputs the instantaneous in-phase component and instantaneous quadrature component at each moment.

[0149] In this embodiment, based on the instantaneous in-phase component and instantaneous quadrature component at each moment, the ripple component to be solved is subtracted from the instantaneous in-phase component to obtain the instantaneous error. Then, the instantaneous error is multiplied by the instantaneous quadrature component to obtain the instantaneous feedback quantity. Finally, the instantaneous feedback quantity is input into the PI control for closed-loop control with respect to the instantaneous angular frequency.

[0150] Specifically, in this embodiment of the application, through steps S231 to S233, the PI controller is controlled to perform closed-loop control of the instantaneous angular frequency of the SOGI filter based on the instantaneous feedback quantity, as shown below:

[0151] Step S231: Determine the proportional term at the current moment based on the product of the instantaneous feedback quantity and the proportional coefficient.

[0152] For example, in this embodiment of the application, the proportional term for the current moment is output according to formula twenty-two, as shown below:

[0153] Formula 22

[0154] in, This is the proportion at the current moment. This is the proportionality coefficient. This represents the instantaneous feedback quantity at the current moment.

[0155] Step S232: Determine the integral term at the current moment based on the feedback cumulative value and the integral coefficient.

[0156] The cumulative feedback value is the sum of all instantaneous feedback quantities from the initial time to the current time. For example, in this embodiment, the integral term at the current time is output according to Formula 23, as shown below:

[0157] Formula 23

[0158] in, This is the integral term at the current moment. The integral coefficient is... This is for feedback of the cumulative value.

[0159] Step S233: Determine the instantaneous angular frequency of the PI controller at the current moment based on the sum of the instantaneous angular frequency, proportional term, and integral term at the initial moment.

[0160] For example, in this embodiment of the application, the instantaneous angular frequency at the current moment is output according to formula twenty-four, as shown below:

[0161] Formula 24

[0162] in, Let be the instantaneous angular frequency at the initial moment. Customized by the designer based on engineering experience, such as the instantaneous angular frequency at the initial moment. This refers to the angular frequency corresponding to 50Hz / 60Hz.

[0163] As shown in Formula 24, the architecture of a PI controller includes a preset term (i.e., the instantaneous angular frequency at the initial moment), a proportional term, and an integral term, among which the instantaneous feedback quantity... The tracking direction and tracking magnitude for the true angular frequency of the ripple component are provided for the proportional and integral terms, respectively.

[0164] Instantaneous angular frequency Not equal to the target angular frequency Instantaneous error Not equal to 0.

[0165] Instantaneous feedback quantity When it is positive, the proportional term can quickly respond to instantaneous feedback. Rapidly increase instantaneous angular frequency Meanwhile, the integral term continuously accumulates the error, and under the influence of the preset term, proportional term, and integral term, the instantaneous angular frequency output by the PI controller... It keeps increasing and getting closer to the target angular frequency. .

[0166] Instantaneous feedback quantity When it is negative, the proportional term can quickly respond to instantaneous feedback. Rapidly reduce instantaneous angular frequency Meanwhile, the integral term continuously reduces the error, and under the influence of the preset term, proportional term, and integral term, the instantaneous angular frequency output by the PI controller... Continuously reduce and continuously approach the target angular frequency .

[0167] Instantaneous angular frequency Equal to target angular frequency Instantaneous error Equal to 0, instantaneous feedback quantity When the value is 0, neither the proportional nor integral term of the PI controller has any adjustment, and the instantaneous angular frequency of the output is zero. Maintaining the target angular frequency This achieves frequency lock-in without steady-state error. Simultaneously, SOGI enters a resonant state, outputting instantaneous in-phase components. and instantaneous orthogonal components This completes the extraction or reconstruction of the ripple component to be solved.

[0168] As mentioned earlier, the output of the SOGI filter is represented by both Equation 18 and Equation 21, where Equation 18 is:

[0169]

[0170] Formula 21 is:

[0171]

[0172] To gain a deeper understanding of the origins of Formula 18 and Formula 21, the derivation process of Formula 18 and Formula 21 is explained in the following embodiments:

[0173] Based on the trigonometric identities, Formula XII is transformed as follows:

[0174] Formula 25

[0175] Expanding formula 25, we get formula 26:

[0176] Formula 26

[0177] because Equivalent to high-frequency oscillation Since the signal is a slowly varying signal, the following approximate equivalent processing can be performed:

[0178] Formula 27

[0179] Formula 28

[0180] Using formulas 27 and 28, we can simplify formula 26 to:

[0181] Formula 29

[0182] when At this time, the SOGI filter is in a resonant state, outputting ideal instantaneous in-phase and instantaneous quadrature components, as shown in Equations 30 and 31:

[0183] Formula 30

[0184] Formula 31

[0185] when When the SOGI filter output deviates from the ideal state, the SOGI filter output includes resonant components (first in-phase resonant component and second in-phase resonant component) and correction components (first in-phase correction component and first quadrature correction component), as shown in Equations 32 and 33:

[0186] Formula 32

[0187] Formula 33

[0188] This is the first in-phase resonant component. This is the first in-phase correction component. This is the second in-phase resonant component. This is the first orthogonal correction component.

[0189] By combining formulas 32, 33, 29, 10, and 11, the resonant component is eliminated, retaining only the lower-order terms of the correction component. The specific process is as follows:

[0190] for The state equations are:

[0191] From the left side of the state equation, we obtain Formula Thirty-Four:

[0192] Formula Thirty-Four

[0193] From the right side of the state equation, we obtain formula 35:

[0194] Formula thirty-five

[0195] Simplifying formula 35, we obtain formula 36:

[0196] Formula Thirty-Six

[0197] The left side of the state equation equals The right side of the state equation can be eliminated. The state equation for the first in-phase correction component is obtained, as shown in Equation 37:

[0198] Formula thirty-seven

[0199] Similarly, for The state equations are:

[0200] By applying the left-hand side of the state equation, we obtain Formula Thirty-Eight:

[0201] Formula 38

[0202] From the right side of the state equation, we obtain formula thirty-nine:

[0203] Formula 39

[0204] Simplifying formula 39, we get formula 40:

[0205] Formula 40

[0206] The left side of the state equation equals The right side of the state equation can be eliminated. The state equation for the first orthogonal corrected component is obtained, as shown in Equation 41:

[0207] Formula 41

[0208] because , for Since it is a slowly varying signal with respect to time t, the forms of the first in-phase correction component and the first quadrature correction component can be:

[0209] Formula 42

[0210] Formula 43

[0211] Based on formula 43, the first orthogonal correction component After differentiation and slow-varying approximation, and combining with formula 41, we have:

[0212] Formula 44

[0213] Due to the first orthogonal correction component The sin term in the equation is a higher-order minor quantity and can be ignored, therefore satisfying the condition. The equation, and then the first in-phase correction component Substituting into Formula 37, the first in-phase correction component... After differentiation and the slowly varying approximation, we have:

[0214] Formula 45

[0215] Eliminate the left and right sides of formula 45. Then, we obtained:

[0216] Formula 46

[0217] Simplifying formula 46, we get:

[0218] Formula 47

[0219] Engineering corrections are made to the coefficient C by introducing a damping term. By suppressing the amplitude of the correction component, we finally obtain:

[0220] Formula 48

[0221] Substituting formula 48 into formulas 42 and 43 respectively, we get:

[0222] Formula 49

[0223] Formula fifty

[0224] By combining formulas 49, 50, and their corresponding formulas, we can obtain formulas 18 and 21.

[0225] Combining formulas 29 and 18, and modifying formula 13, we have:

[0226] Formula 51

[0227] The instantaneous error of formula fifty-one and instantaneous orthogonal components Multiplying them together, ignoring higher-order terms, we get:

[0228] Formula 52

[0229] From formula 51, we can see that the instantaneous error For high-frequency AC signals, if instantaneous error Inconsistent instantaneous orthogonal components Multiply, because The frequency fluctuates between [-1, 1], which prevents the integral term of the PI controller from effectively canceling the error corresponding to the high-frequency AC signal, thus affecting the instantaneous angular frequency output of the PI controller. At true angular frequency It fluctuates repeatedly in the vicinity.

[0230] As can be seen from Formula 52, if the instantaneous error and instantaneous orthogonal components Multiplying, because Therefore, instantaneous feedback quantity It can provide a directional convergence direction for the integral term of the PI controller, so that the instantaneous angular frequency of the PI controller output is... It can accurately and reliably adaptively converge to the true angular frequency. .

[0231] Take one period for formula 52 The mean of is:

[0232] Formula 53

[0233] Instantaneous angular frequency Less than the target angular frequency Under the premise that, due to Therefore, the integral term of the PI controller will continuously accumulate, thus increasing the instantaneous angular frequency. until .

[0234] Instantaneous angular frequency Greater than the target angular frequency Under the premise that, due to Therefore, the integral term of the PI controller will continuously decrease, thus lowering the instantaneous angular frequency. until .

[0235] When the instantaneous angular frequency Equal to target angular frequency Under the premise that, at this time Substituting into Formula 18 and Formula 21, we can obtain the instantaneous in-phase component and the instantaneous quadrature component whose instantaneous angular frequency is equal to the target angular frequency.

[0236] At this moment, the instantaneous in-phase components With the ripple component to be solved Same frequency and phase, Since the value is 0, the target loop operates stably, achieving frequency locking.

[0237] Based on the extracted ripple component In conjunction with Formula 7, the embodiments of this application subtract the extracted ripple component from the target bus voltage signal. At this time, the ripple component in the target bus voltage signal The DC component has been suppressed, resulting in a pure DC component. .

[0238] To demonstrate the technical effects of the embodiments of this application, the embodiments of this application are combined with Figure 5 and Figure 6 This is explained in detail below:

[0239] Please see Figure 5 The voltage detection circuit samples the DC bus voltage to obtain the original bus voltage signal 51. For example... Figure 5 As shown, the shape of the original bus voltage signal 51 should be approximately a straight line under the premise of not being affected by ripple interference and random high-frequency noise interference. However, due to ripple interference and random high-frequency noise interference, the shape of the original bus voltage signal 51 is a sine wave.

[0240] Please see Figure 6In this embodiment, ripple extraction and ripple suppression are performed on the original bus voltage signal 51 to obtain DC component 52. The shape of DC component 52 is approximately a straight line, achieving the expected effect.

[0241] As another aspect of this application, this application provides a method for suppressing ripple signals. Please refer to... Figure 7 The ripple signal suppression method includes the following steps:

[0242] S71, acquire the original bus voltage signal.

[0243] The voltage detection circuit performs voltage sampling on the DC bus to obtain the original bus voltage signal.

[0244] S72 uses a preset low-pass filter to perform high-frequency noise filtering on the original bus voltage signal to obtain the target bus voltage signal.

[0245] Preset low-pass filters include hardware low-pass filter circuits or software first-order infinite impulse response low-pass filters.

[0246] S73, the ripple component of the target bus voltage signal is extracted using the ripple component extraction method described above.

[0247] S74, based on the difference between the target bus voltage signal and the ripple component, determines the DC component in the original bus voltage signal.

[0248] This application embodiment eliminates the need for additional hardware circuitry, enabling the extraction and suppression of ripple components via software. This facilitates the miniaturization of the energy storage system and reduces hardware costs. Furthermore, this application embodiment constructs an instantaneous feedback quantity based on instantaneous quadrature components and instantaneous errors. This instantaneous feedback quantity provides the PI controller with the tracking direction and magnitude of the true angular frequency of the ripple component, allowing the instantaneous angular frequency output by the PI controller to accurately and reliably converge adaptively to the target angular frequency. The SOGI filter, based on the target angular frequency fed back by the PI controller, outputs an instantaneous in-phase component consistent with the ripple component, thereby adaptively extracting or reconstructing the ripple component to be solved, and thus adaptively suppressing the ripple component to obtain an accurate and reliable DC component.

[0249] It should be noted that for technical details not described in detail in the embodiments of the ripple signal suppression method, please refer to the embodiments of the ripple component extraction method provided in this application.

[0250] It should be noted that in the above embodiments, there is no necessarily a certain order between the steps. Those skilled in the art can understand from the description of the embodiments of this application that the above steps may have different execution orders in different embodiments, that is, they may be executed in parallel or in turn, etc.

[0251] As another aspect of the embodiments of this application, this application provides a ripple component extraction device. The ripple component extraction device can be a software module, which includes several instructions stored in a memory. A processor can access the memory and execute the instructions to complete the ripple component extraction methods described in the various embodiments above.

[0252] Please see Figure 8 The ripple component extraction device 800 includes a signal acquisition module 81 and an SOGI filter module 82 and a closed-loop control module 83 that interact with each other and form a target loop.

[0253] The signal acquisition module 81 is used to acquire the target bus voltage signal, which includes the ripple component to be solved. The SOGI filter module 82 is used to output instantaneous in-phase and instantaneous quadrature components based on the target bus voltage signal and the instantaneous angular frequency output by the closed-loop control module. The closed-loop control module 83 is used to perform closed-loop control of the instantaneous angular frequency fed back to the SOGI filter module based on the instantaneous feedback quantity, so that the instantaneous angular frequency converges to the target angular frequency. The instantaneous feedback quantity is determined based on the instantaneous error between the instantaneous quadrature component and the SOGI filter, and the instantaneous error is the difference between the ripple component to be solved and the instantaneous in-phase component.

[0254] When the instantaneous angular frequency output by the PI controller converges to the target angular frequency, the SOGI filter module 82 outputs an instantaneous angular frequency that is the instantaneous in-phase component of the target angular frequency based on the target angular frequency fed back by the PI controller.

[0255] In some embodiments, the closed-loop control module 83 is specifically used to: determine the proportional term at the current moment based on the product of the instantaneous feedback quantity and the proportional coefficient at the current moment; determine the integral term at the current moment based on the cumulative feedback value and the integral coefficient; the cumulative feedback value is the sum of all instantaneous feedback quantities from the initial moment to the current moment; and determine the instantaneous angular frequency of the PI controller at the current moment based on the sum of the instantaneous angular frequency, the proportional term, and the integral term at the initial moment.

[0256] In some embodiments, the closed-loop control module 83 is further specifically configured to: determine the first in-phase resonant component of the sine waveform based on the instantaneous angular frequency output by the PI controller and the amplitude of the ripple component to be solved; determine the instantaneous correction amplitude based on the instantaneous difference of angular frequency and the amplitude of the ripple component to be solved, wherein the instantaneous difference of angular frequency is the difference between the target angular frequency and the instantaneous angular frequency; determine the first in-phase correction component of the cosine waveform based on the instantaneous angular frequency output by the PI controller and the instantaneous correction amplitude; and determine the instantaneous in-phase component based on the sum of the first in-phase resonant component and the first in-phase correction component.

[0257] In some embodiments, the closed-loop control module 83 is further specifically configured to: determine the second in-phase resonant component of the cosine waveform based on the instantaneous angular frequency output by the PI controller and the amplitude of the ripple component to be solved; determine the instantaneous correction amplitude based on the instantaneous difference of angular frequency and the amplitude of the ripple component to be solved, wherein the instantaneous difference of angular frequency is the difference between the target angular frequency and the instantaneous angular frequency; determine the first quadrature correction component of the sine waveform based on the instantaneous angular frequency output by the PI controller and the instantaneous correction amplitude; and determine the instantaneous quadrature component based on the difference between the second in-phase resonant component and the first quadrature correction component.

[0258] In some embodiments, the closed-loop control module 83 is further specifically configured to: determine the first product result of the instantaneous difference of angular frequency and the amplitude of the ripple component to be solved; determine the second product result of the preset damping coefficient of the state equation of the instantaneous angular frequency output by the PI controller and the output result of the SOGI filter at each moment; and determine the instantaneous correction amplitude at each moment based on the quotient of the first product result and the second product result.

[0259] In some embodiments, the instantaneous feedback quantity is the product of the instantaneous quadrature component and the instantaneous error of the SOGI filter.

[0260] As another aspect of the embodiments of this application, this application provides a ripple signal suppression device. The ripple signal suppression device can be a software module, which includes several instructions stored in a memory. A processor can access the memory, call the instructions, and execute them to complete the ripple signal suppression methods described in the various embodiments above.

[0261] Please see Figure 9 The ripple signal suppression device 900 includes a signal sampling module 91, a low-pass filter module 92, a ripple extraction module 93, and a DC extraction module 94.

[0262] The signal sampling module 91 is used to acquire the original bus voltage signal, the low-pass filtering module 92 is used to perform high-frequency noise filtering on the original bus voltage signal using a preset low-pass filter to obtain the target bus voltage signal, the ripple extraction module 93 is used to extract the ripple component of the target bus voltage signal using the above-mentioned ripple component extraction method, and the DC extraction module 94 is used to determine the DC component in the original bus voltage signal based on the difference between the target bus voltage signal and the ripple component.

[0263] It should be noted that the above-described ripple signal suppression device can execute the ripple signal suppression method provided in the embodiments of this application, and has the corresponding functional modules and beneficial effects of the method. Technical details not described in detail in the embodiments of the ripple signal suppression device can be found in the ripple signal suppression method provided in the embodiments of this application.

[0264] See Figure 10 , Figure 10 This is a schematic diagram of the structure of a power device provided in an embodiment of this application. The power device 101 includes one or more processors 102 and a memory 103. The memory 103 is connected to one or more processors 102, for example, via a bus.

[0265] Processor 102 is configured to support the power equipment in performing the corresponding functions in the methods described in the above method embodiments. The processor may be a central processing unit (CPU), a network processor (NP), a hardware chip, or any combination thereof. The aforementioned hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The aforementioned PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

[0266] Memory 103 is used to store program code, etc. Memory may include volatile memory (VM), such as random access memory (RAM); memory may also include non-volatile memory (NVM), such as read-only memory (ROM), flash memory, hard disk drive (HDD), or solid-state drive (SSD); memory may also include combinations of the above types of memory.

[0267] The memory 103 can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules, such as the program instructions / modules corresponding to the ripple component extraction method or ripple signal suppression method in the embodiments of this application. The processor executes the non-volatile software programs, instructions, and modules stored in the memory to perform various functional applications and data processing of the ripple component extraction method, ripple signal suppression method, ripple component extraction device, or ripple signal suppression device, thereby realizing the functions of each module or unit of the ripple component extraction method, ripple signal suppression method, ripple component extraction device, or ripple signal suppression device provided in the above method embodiments.

[0268] The memory 103 may include a program storage area and a data storage area, wherein the program storage area may store the operating system and application programs required for at least one function. The data storage area may store data created based on the use of the ripple component extraction device or the ripple signal suppression device. In some embodiments, the memory may optionally include memory remotely located relative to the processor, which can be connected to the ripple component extraction device or the ripple signal suppression device via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0269] The one or more modules are stored in the memory. When executed by the one or more processors, they perform the ripple component extraction method or ripple signal suppression method in any of the above method embodiments. For example, they perform the method steps described in the above method embodiments to realize the functions of the modules described in the above device embodiments.

[0270] This application also provides a computer-readable storage medium storing a computer program, the computer program including program instructions, which, when executed by a processor, cause the processor to perform the above-described method.

[0271] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0272] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the claims of this application shall still fall within the scope of this application.

Claims

1. A method for extracting ripple components, characterized in that, include: Acquire the target bus voltage signal, which includes the ripple component to be solved; The target bus voltage signal and the instantaneous angular frequency output by the PI controller of the target loop are input to the SOGI filter of the target loop for processing, so that the SOGI filter outputs instantaneous in-phase components and instantaneous quadrature components, and the instantaneous angular frequency at the initial moment is a preset value. The PI controller is controlled to perform closed-loop control of the instantaneous angular frequency fed back to the SOGI filter based on the instantaneous feedback quantity, so that the instantaneous angular frequency converges to the target angular frequency. The instantaneous feedback quantity is determined based on the instantaneous error between the instantaneous quadrature component and the SOGI filter. The instantaneous error is the difference between the ripple component to be solved and the instantaneous in-phase component. When the instantaneous angular frequency converges to the target angular frequency, the SOGI filter outputs the instantaneous in-phase component of the target angular frequency based on the target angular frequency fed back by the PI controller.

2. The extraction method according to claim 1, characterized in that, Controlling the PI controller to perform closed-loop control of the instantaneous angular frequency fed back to the SOGI filter based on the instantaneous feedback quantity includes: The proportional term at the current moment is determined by multiplying the instantaneous feedback quantity at the current moment with the proportional coefficient. Based on the cumulative feedback value and the integral coefficient, the integral term at the current moment is determined, wherein the cumulative feedback value is the sum of all the instantaneous feedback quantities from the initial moment to the current moment; The instantaneous angular frequency of the PI controller at the current moment is determined based on the sum of the instantaneous angular frequency, the proportional term, and the integral term at the initial moment.

3. The extraction method according to claim 1, characterized in that, The target bus voltage signal and the instantaneous angular frequency output by the PI controller of the target loop are input to the SOGI filter of the target loop for processing, so that the SOGI filter outputs an instantaneous in-phase component, including: Based on the instantaneous angular frequency output by the PI controller and the amplitude of the ripple component to be solved, the first in-phase resonant component of the sine waveform is determined. Based on the instantaneous difference in angular frequency and the amplitude of the ripple component to be solved, the instantaneous correction amplitude is determined, wherein the instantaneous difference in angular frequency is the difference between the target angular frequency and the instantaneous angular frequency; Based on the instantaneous angular frequency and the instantaneous correction amplitude output by the PI controller, the first in-phase correction component of the cosine waveform is determined; The instantaneous in-phase component is determined based on the sum of the first in-phase resonant component and the first in-phase correction component.

4. The extraction method according to claim 1, characterized in that, The target bus voltage signal and the instantaneous angular frequency output by the PI controller of the target loop are input to the SOGI filter of the target loop for processing, so that the SOGI filter outputs instantaneous quadrature components, including: Based on the instantaneous angular frequency output by the PI controller and the amplitude of the ripple component to be solved, the second in-phase resonant component of the cosine waveform is determined. Based on the instantaneous difference in angular frequency and the amplitude of the ripple component to be solved, the instantaneous correction amplitude is determined, wherein the instantaneous difference in angular frequency is the difference between the target angular frequency and the instantaneous angular frequency; Based on the instantaneous angular frequency and the instantaneous correction amplitude output by the PI controller, the first orthogonal correction component of the sine waveform is determined; The instantaneous quadrature component is determined based on the difference between the second in-phase resonant component and the first quadrature correction component.

5. The extraction method according to any one of claims 3 or 4, characterized in that, Based on the instantaneous difference in angular frequency and the amplitude of the ripple component to be solved, the instantaneous correction amplitude is determined, including: Determine the first product result of the instantaneous difference of the angular frequency and the amplitude of the ripple component to be solved; The second product of the state equation of the instantaneous angular frequency output by the PI controller and the output result of the SOGI filter at each moment is determined by the preset damping coefficient. The instantaneous correction magnitude at each moment is determined based on the quotient of the first product result and the second product result.

6. The extraction method according to any one of claims 1 to 4, characterized in that, The instantaneous feedback quantity is determined based on the instantaneous error between the instantaneous quadrature component and the SOGI filter, and is as follows: The instantaneous feedback quantity is the product of the instantaneous quadrature component and the instantaneous error of the SOGI filter.

7. A method for suppressing ripple signals, characterized in that, include: Obtain the raw bus voltage signal; The original bus voltage signal is filtered for high-frequency noise using a preset low-pass filter to obtain the target bus voltage signal. The ripple component of the target bus voltage signal is extracted using the ripple component extraction method as described in any one of claims 1 to 6. The DC component in the original bus voltage signal is determined based on the difference between the target bus voltage signal and the ripple component.

8. A ripple component extraction device, characterized in that, It includes a signal acquisition module, an SOGI filter module that interacts with each other and forms the target loop, and a closed-loop control module; The signal acquisition module is used to acquire the target bus voltage signal, which includes the ripple component to be solved. The SOGI filter module is used to output instantaneous in-phase components and instantaneous quadrature components based on the target bus voltage signal and the instantaneous angular frequency output by the closed-loop control module. The closed-loop control module is used to perform closed-loop control of the instantaneous angular frequency fed back to the SOGI filter module based on the instantaneous feedback quantity, so that the instantaneous angular frequency converges to the target angular frequency. The instantaneous feedback quantity is determined based on the instantaneous error between the instantaneous quadrature component and the SOGI filter. The instantaneous error is the difference between the ripple component to be solved and the instantaneous in-phase component. When the instantaneous angular frequency output by the PI controller converges to the target angular frequency, the SOGI filter module outputs the instantaneous in-phase component of the target angular frequency based on the target angular frequency fed back by the PI controller.

9. An electrical device, characterized in that, The device includes a memory and a processor, the memory being connected to the processor, the processor being configured to execute one or more computer programs stored in the memory, wherein, when executing the one or more computer programs, the processor causes the power equipment to implement the ripple component extraction method as described in any one of claims 1-6 or the ripple signal suppression method as described in claim 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, the computer program including program instructions, which, when executed by a processor, cause the processor to perform the ripple component extraction method as described in any one of claims 1-6 or the ripple signal suppression method as described in claim 7.

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