A single-stage multi-port converter DC side current ripple suppression method, device and storage medium

Abstract

The application discloses a single-stage multi-port converter DC side current ripple suppression method and device and a storage medium. The method comprises the following steps: obtaining an initial three-phase sinusoidal modulation wave according to three-phase voltage and current on the AC side of the converter; obtaining a battery current control value according to a DC side photovoltaic voltage and current; obtaining an asymmetric carrier according to the DC side photovoltaic voltage and an energy storage battery voltage; obtaining an actual battery current value according to the initial three-phase sinusoidal modulation wave and the asymmetric carrier, and performing iteration according to the error between the actual value and the control value to obtain a zero sequence component when the error is less than an error tolerance; injecting the zero sequence component into the initial three-phase sinusoidal modulation wave to obtain an improved modulation wave; and intersecting the improved modulation wave with the asymmetric carrier to obtain a converter PWM driving signal. The application realizes DC side current ripple suppression and power distribution between the photovoltaic and the energy storage battery through a zero sequence component injection method, and has the characteristics of remarkable ripple suppression effect and low implementation cost.

Description

Technical Field

[0001] This invention belongs to the field of control technology for power electronic converters, and in particular relates to a method, device and storage medium for suppressing DC side current ripple in a single-stage multi-port converter. Background Technology

[0002] With the escalating global energy crisis and environmental pollution, grid-connected power generation from renewable energy sources (photovoltaics, wind power, etc.) has begun to develop rapidly. However, considering that renewable energy power generation, especially photovoltaic power generation, is susceptible to natural conditions and suffers from intermittency and uncertainty, its power generation circuit topology and control methods are still being improved. Existing research has found that using integrated photovoltaic energy storage systems can effectively avoid problems such as fluctuations in photovoltaic output.

[0003] In recent years, a single-stage multi-port converter structure has gradually emerged in the research of integrated photovoltaic and energy storage systems. This structure can simultaneously connect photovoltaic units, energy storage batteries, and the AC grid through a single-stage converter, and has advantages such as high integration, high efficiency, low switching losses, and low voltage harmonics, making it the primary choice for efficient power conversion.

[0004] In the research of single-stage multi-port converters, Chinese invention patent CN110601583A proposes a converter structure with a three-port distributed photovoltaic energy storage hybrid structure. This converter adopts a single-star topology and includes an energy storage medium section, a power stage section, and an LCL filter section. This invention circuit has advantages such as simple structure, dispatchability, and good grid-connected power quality. However, this invention only includes the structural topology and does not explain its specific modulation method. If it is modulated according to a three-level converter, there will be AC ​​current ripple on the photovoltaic energy storage side, which will affect the internal resistance, temperature, capacity, and other physical quantities of the battery, and thus affect the battery's service life. At the same time, the output power distribution between the photovoltaic and energy storage sides is uneven and the ratio of photovoltaic to energy storage power is difficult to change, which cannot solve the randomness problem of photovoltaic power generation.

[0005] Chinese invention patent CN115765509A proposes a power distribution method for a dual-DC-port asymmetric three-level grid-connected inverter. This invention designs a dynamically adjustable control parameter p for the DC port output power and generates a modulation wave correction component through this parameter. This component is injected into the original three-phase modulation wave as a zero-sequence component to form an asymmetric modulation wave signal. This modulation method can realize real-time power distribution between the two DC ports of photovoltaic energy storage, but it still does not solve the problem of DC side current ripple.

[0006] Chinese invention patent CN119298634A discloses a method and system for suppressing DC-side capacitor current ripple in a coupled three-level inverter. The invention employs VSVPWM (Virtual Space Vector Pulse Width Modulation), and designs a controller based on a deadbeat control method according to the DC-side capacitor voltage deviation to achieve independent capacitor voltage control, thereby designing a switching sequence to suppress capacitor current ripple. However, although single-stage multi-port converters have the same topology as three-level inverters, the battery is connected at the inverter midpoint, allowing for arbitrary selection of the battery voltage. The photovoltaic voltage is no longer equal to twice the battery voltage, and the battery connection also enables the inverter midpoint to output power. Therefore, this method is no longer suitable for single-stage multi-port converters, and a method for suppressing DC-side ripple in single-stage multi-port converters urgently needs further research. Summary of the Invention

[0007] The purpose of this invention is to provide a method, device, and storage medium for suppressing DC-side current ripple in a single-stage multi-port converter. The method achieves DC-side current ripple suppression and power distribution between the photoelectric storage device through zero-sequence component injection, and features significant ripple suppression effect and low implementation cost.

[0008] To achieve the above objectives, the solution of the present invention is:

[0009] A method for suppressing DC-side current ripple in a single-stage multi-port converter includes,

[0010] Based on the three-phase AC voltage and current of the single-stage multi-port converter, the initial three-phase sinusoidal modulation wave is obtained; based on the DC photovoltaic voltage and current, the battery current control value is obtained; based on the DC photovoltaic voltage and energy storage battery voltage, the asymmetric carrier wave is obtained.

[0011] Based on the initial three-phase sinusoidal modulation wave and asymmetric carrier wave, the actual value of the battery current is obtained, and the difference between the actual value of the battery current and the battery current control value is calculated. The error is then iterated to obtain the zero-sequence component corresponding to the error being less than the error tolerance.

[0012] The zero-sequence component is injected into the initial three-phase sinusoidal modulation wave to obtain the improved modulation wave;

[0013] The improved modulation wave is intersected with the asymmetric carrier wave to obtain the converter PWM drive signal.

[0014] The initial three-phase sinusoidal modulation wave is obtained based on the three-phase voltage and current on the AC side of the single-stage multi-port converter, including:

[0015] The three-phase voltage and current on the AC side of the single-stage multi-port converter were obtained by sampling.

[0016] The initial three-phase sinusoidal modulation wave is obtained by performing dual closed-loop control on the three-phase voltage and current;

[0017] Among them, the battery current control value is obtained based on the DC-side photovoltaic voltage and current, including,

[0018] The DC-side photovoltaic voltage and current of the converter were obtained through sampling.

[0019] The photovoltaic voltage and current are processed by MPPT (Maximum Power Point Tracking) and DC-side power control to obtain the battery current control value.

[0020] Among them, the asymmetric carrier wave is obtained based on the DC-side photovoltaic voltage and the energy storage battery voltage, including:

[0021] The asymmetric carrier boundary is obtained according to the following formula. ,

[0022]

[0023] in, This refers to the photovoltaic voltage on the DC side of the converter. This refers to the voltage of the DC-side energy storage battery in the converter.

[0024] In a single-stage multi-port converter, the asymmetric carrier consists of two triangular carriers with equal frequency, same phase, but different ranges, based on the asymmetric carrier boundary line. Set the carrier range as , This results in an asymmetric carrier wave.

[0025] The actual battery current value is obtained based on the initial three-phase sinusoidal modulation wave and the asymmetric carrier wave, including:

[0026] Based on the initial three-phase sinusoidal modulation wave and asymmetric carrier boundary line To establish the relationship between battery current and modulation wave,

[0027]

[0028] in, This represents the average value of the battery current in each phase over one switching cycle. represent Three phases; The initial value for the zero-order component. This refers to the three-phase current on the AC side.

[0029] The sum of the three-phase battery currents gives the actual battery current of the multi-port converter. ,

[0030] .

[0031] Specifically, based on the initial three-phase sinusoidal modulation wave and combined with the asymmetric carrier boundary line of the single-stage multi-port converter, the actual battery current value is obtained. The difference between the actual battery current value and the battery current control value is calculated, and the resulting error is iterated to obtain the zero-sequence component corresponding to when the error is less than the error tolerance. This includes...

[0032] Step A: Determine if the difference between the current maximum and minimum values ​​is greater than the error tolerance. If it is, continue with the following steps using the current zero-order component; otherwise, use the current zero-order component as the final zero-order component. Here, the zero-order component is defined. , , These are the current iteration's maximum and minimum values, respectively.

[0033] Step B: Combine the current initial value of the zero-sequence component with the initial three-phase sinusoidal modulation wave and the asymmetric carrier boundary line to obtain the actual value of the battery current.

[0034] Step C: Obtain the error between the actual battery current value and the battery current control value. When the error is greater than 0, adjust the current... Update as the maximum value of the iteration; otherwise, update the current value. Update the minimum value of the iteration; return to step A.

[0035] In step C, obtaining the error between the actual battery current value and the battery current control value includes,

[0036] Constructing the error function ,in, This is the battery current control value. This represents the average value of the battery current in each phase over one switching cycle. represent Three phases.

[0037] The improved modulation wave is intersected with the asymmetric carrier wave to obtain the converter PWM drive signal, including:

[0038] The improved modulation wave is combined with an asymmetric carrier, and the converter PWM drive signal is obtained by using a carrier-based pulse width modulation (CBPWM) algorithm.

[0039] A control device based on a method for suppressing DC-side current ripple in a single-stage multi-port converter includes a memory, a processor, and a program stored in the memory; when the processor executes the program, it implements the method described above.

[0040] A storage medium having a program stored thereon; when the program is executed, it implements the method described above.

[0041] By adopting the above solution, the present invention has the following beneficial effects compared with the prior art:

[0042] 1. The DC-side current ripple suppression method for a single-stage multi-port converter proposed in this invention obtains a specific zero-sequence component through iterative calculation and injects the zero-sequence component into the initial modulation wave, thereby changing the duty cycle of the PWM drive signal to form an improved three-phase modulation wave. This controls the single-stage multi-port converter and effectively suppresses the ripple of the DC output current at both ends of the photovoltaic and energy storage terminals without changing the AC output, thus avoiding the reduction in the lifespan of the energy storage battery due to ripple.

[0043] 2. The DC-side current ripple suppression method for single-stage multi-port converter proposed in this invention can not only suppress the AC current ripple at the DC terminals of the photovoltaic and energy storage systems, but also achieve accurate power distribution at the photovoltaic and energy storage ports by directly controlling the battery output current value. Attached Figure Description

[0044] Figure 1 This is a topology diagram of the single-stage multi-port converter system of the present invention;

[0045] Figure 2 This is a control block diagram of the DC-side current ripple suppression strategy based on zero-sequence component injection of the present invention;

[0046] Figure 3 This is a schematic diagram of the principle of asymmetric carrier waveform formation;

[0047] Figure 4 This is a schematic diagram illustrating the construction of the mathematical expression for battery current;

[0048] Figure 5 This is a flowchart of the zero-sequence component calculation in an embodiment of the present invention;

[0049] Figure 6 This is an experimental waveform diagram of the converter system of the present invention without DC-side ripple suppression control;

[0050] Figure 7 This is an experimental waveform diagram of the converter system of the present invention when it has DC-side ripple suppression control;

[0051] Wherein: H, L, and N are the DC input terminals of the converter; H is the photovoltaic connection; L is the battery connection; and N is the negative terminal connection of both power sources; A, B, and C are the grid-connected terminals of the converter; and G is the grid neutral point. For converter filter inductance, Its corresponding equivalent impedance; The equivalent inductance on the AC power grid side; , For DC-side photovoltaic and battery voltages; , For photovoltaics and batteries; , , The sampled three-phase AC voltage on the grid side; , , The sampled three-phase AC current on the power grid side; , , This refers to the three-phase voltage on the grid-connected side. Detailed Implementation

[0052] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0053] It is worth noting that although the following detailed description of this embodiment represents only one specific implementation of the invention. In fact, the invention encompasses a variety of possible embodiments, which may have various variations and optimizations. Based on the technical principles and methods disclosed in this invention, those skilled in the art can derive other implementation schemes without inventive modifications, and all such schemes should be considered within the scope of protection of this invention.

[0054] For ease of description, the relevant technical terms appearing in the specific implementation method will be explained first:

[0055] MPPT (Maximum Power Point Tracking): Maximum Power Point Tracking;

[0056] CBPWM (Carrier-based Pulse Width Modulation): Carrier pulse width modulation.

[0057] This embodiment provides a method for suppressing DC-side current ripple in a single-stage multi-port converter. This method is applicable to one or more single-stage multi-port converters and includes the following steps:

[0058] The DC side samples the photovoltaic voltage and current, and determines the control value of the battery current through MPPT tracking and DC side power control; it samples the three-phase output voltage and current of the AC side of the converter, and obtains the initial reference sinusoidal modulation wave through dual closed-loop control.

[0059] The DC-side photovoltaic voltage and energy storage battery voltage of the grid-connected converter are sampled to form an asymmetric carrier wave.

[0060] Based on the sampled three-phase current, initial modulation wave, battery current control value and converter asymmetric carrier wave, the zero-sequence voltage component is formed by iterative calculation.

[0061] The zero-sequence voltage component is injected into the initial three-phase modulation wave to obtain an improved modulation wave;

[0062] By combining the aforementioned asymmetric carrier wave with the improved modulation wave, a drive signal for the converter is generated, thereby achieving AC ripple suppression of the DC-side current while simultaneously realizing the distribution of photovoltaic and energy storage power.

[0063] like Figure 1 As shown, the converter structure constructed in this embodiment is a dual-DC-port T-type three-level grid-connected converter. The upper port H is connected to the photovoltaic system, the middle port L is connected to the battery, and the lower port N is the negative bus of both power sources. The DC side is connected to the AC side through a T-type three-phase bridge arm, and the AC side is connected through a filter inductor. and its equivalent impedance Grid connection was later achieved. This is the equivalent inductance on the grid side.

[0064] like Figure 2 As shown, after the converter starts up, the photovoltaic voltage can be obtained by sampling the DC side photovoltaic and energy storage battery voltages of the converter. and energy storage voltage And thereby obtain the upper and lower boundaries of the asymmetric carrier. , The calculation formula is as follows:

[0065]

[0066] Photovoltaic voltage on the DC side of the converter and current The battery current control value is determined by sampling, MPPT tracking, and DC-side power control. The three-phase voltage is obtained by sampling the AC side voltage and current of the converter. and three-phase current The initial reference sinusoidal modulation wave is obtained by performing dual closed-loop control on the three-phase AC voltage and current. Define zero-order components The initial value, and compared with the reference sinusoidal modulated wave. The three-phase current obtained from sampling Asymmetric carrier boundary line and battery current control value By combining these calculations, the corresponding battery currents are determined and summed to obtain the actual battery current value. ; Set the current control value The error function is obtained by subtracting this current value. ,in accordance with Iterate over the value until... If the value is less than the error limit, then the zero-sequence voltage component to be injected is calculated. , zero-order component Injected into the reference sinusoidal modulated wave Improved modulation wave obtained After CBPWM modulation, the converter is driven to achieve DC-side current ripple suppression. Specifically, the modulation waveform is improved. The range should be [-1, 1].

[0067] like Figure 3 The diagram shown illustrates the principle of asymmetric carrier waveform formation, where the photovoltaic voltage is sampled. Battery voltage Then, the boundary between asymmetric up and down carriers was calculated. Based on the different numerical relationships between the two DC voltages, they can be divided into , , Three scenarios. Asymmetric carriers consist of two triangular carriers with equal frequencies, identical phases, but unequal ranges. Their carrier ranges are as follows: , The modulated wave and the asymmetric carrier can generate the control signal for the IGBT in the multi-port converter under asymmetric conditions.

[0068] like Figure 4 The diagram shows the construction of the mathematical expression for battery current. When the modulated wave is at the asymmetric carrier boundary... Above, when the modulated wave is greater than the carrier wave, the circuit is connected to the photovoltaic side. , When the modulated wave is less than the carrier wave, the circuit connects to the battery side. , When the circuit is turned on, the battery discharges; when the modulated wave is at the asymmetric carrier boundary... When the modulated wave is greater than the carrier wave, the circuit connects to the battery side. , When the circuit is on, the battery charges; when the modulated wave is less than the carrier wave, the circuit connects to the negative terminal of the DC source. , Conduction.

[0069] Based on the average switching model, the average value of the midpoint current of a phase in the inverter over one switching cycle is equal to the product of the instantaneous value of the AC current in that phase and the duty cycle of the circuit connection midpoint within one switching cycle. From this model, the relationship between the battery current and the modulation wave can be constructed. The expressions for the duty cycle of each phase connected to the battery side are as follows:

[0070]

[0071] From the duty cycle expression, the average value of the battery current during each phase over the switching cycle can be obtained as follows:

[0072]

[0073] In the formula, In this embodiment, the three-phase modulation wave in the average switching model is the improved three-phase modulation wave after superimposing the zero-sequence component. represent Three phases; The sampled three-phase alternating current; This is the boundary line between asymmetric carrier waves; This represents the average value of the battery current in each phase over one switching cycle.

[0074] Will The expression expands to:

[0075]

[0076] The sum of the three-phase battery currents equals the battery output current of the multi-port converter. :

[0077]

[0078] Battery output current Approaching the battery current control rating And based on this, an iterative method is used to solve for the zero-order component to be injected. This zero-sequence component injection enables DC-side current ripple suppression of the multi-port converter and power distribution between the photovoltaic and energy storage systems.

[0079] like Figure 5 The diagram shown is a flowchart of the zero-sequence component calculation in this embodiment. This embodiment specifically uses an iterative method to obtain the zero-sequence component to be injected, which includes the following steps:

[0080] Step 1: Set the iteration range of the zero-sequence component and set the maximum value. and minimum value and set The initial value is ;

[0081] Step 2, Judgment and Whether the difference is greater than the error tolerance is used as a condition for whether to continue iterating. If the difference is greater than the tolerance, it needs to be iterated again; if the difference is less than the tolerance, the result converges and can be used as the final value, which is then output after being limited to the range of [-0.5, 0.5].

[0082] Step 3: Determine the initial modulation wave based on the relationship established by the converter midpoint current calculation model. With zero-order components Is the sum greater than the asymmetric carrier boundary? Then, select the corresponding battery current expression and calculate the value of the three-phase battery current;

[0083] Step 4: Construct the error function The sum of the three-phase battery currents Controlled within the commanded value to achieve AC ripple suppression of DC-side current and power distribution between photovoltaic and energy storage systems. If , at this time Reassigned to Proceed to the next iteration; if Then at this time Reassigned to Then proceed to the next iteration.

[0084] In this invention, photovoltaic output power is tracked in real time through photovoltaic MPPT control. And based on photovoltaic output power With grid-side power DC-side power control is performed, and the power control module outputs a control value for the battery current to control the photovoltaic output power. Battery output power Grid-side power To achieve a balance between supply and demand.

[0085] To verify the effectiveness of the control method described in this invention, a specific example will be given. The main parameters of the dual DC port T-type three-level converter are as follows:

[0086] Photovoltaic port voltage ;

[0087] Battery port voltage ;

[0088] AC power grid line voltage RMS value ;

[0089] AC power grid frequency ;

[0090] Converter rated output power ;

[0091] Switching frequency ;

[0092] Filter inductor .

[0093] like Figure 6The figure shows the photovoltaic and battery current waveforms of a dual DC port T-type three-level converter without the control method of this invention. As can be seen from the figure, the current ripple on both DC sides is relatively large under this operating condition, with the photovoltaic side current ripple reaching 3.5A and the battery current ripple reaching 5.5A.

[0094] like Figure 7 The image shows the battery current control command value. The photovoltaic and battery current waveforms using the control method provided by this invention are obtained through... Figure 6 and Figure 7 The comparison shows that by adopting the control method for suppressing DC-side current ripple proposed in this invention, the AC current ripple on the DC side can be suppressed to within 0.2A, and the control of the battery current value also realizes the power distribution between photovoltaic and energy storage.

[0095] In this embodiment, the method described in this invention achieves the suppression of DC-side current ripple, thereby verifying the effectiveness of the current ripple suppression strategy of this invention.

[0096] This invention also provides a control device based on a method for suppressing DC-side current ripple in a single-stage multi-port converter, comprising a memory, a processor, and a program stored in the memory; the processor executes the program to implement the method described above.

[0097] This invention also provides a storage medium on which a program is stored; when the program is executed, it implements the method described above.

[0098] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

[0099] The above description is based on flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments. It should be emphasized that computer program instructions can be designed to implement each block of the flowcharts and / or block diagrams, as well as combinations of blocks in the flowcharts and / or block diagrams. These computer program instructions can run on a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing device to create a machine that, by executing the instructions of the processor of the computer or other programmable data processing device, implements the functionality of one or more blocks specified in the flowcharts and / or block diagrams.

[0100] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0101] It is important to note that in this invention, terms such as "comprising" and "including" are used only to distinguish one entity or operation from another, and do not necessarily indicate any actual relationship or order between these entities or operations. Furthermore, the use of the terms "comprising," "including," or variations thereof is intended to cover non-exclusive inclusion, that is, including not only the listed elements but also other elements not expressly listed, or elements that are inherent to the process, method, article, or apparatus. Unless otherwise specified, the use of the phrase "comprising one..." to define an element does not exclude the possibility of the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0102] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0103] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for suppressing DC-side current ripple in a single-stage multi-port converter, characterized in that: include, Based on the three-phase AC voltage and current of the single-stage multi-port converter, the initial three-phase sinusoidal modulation wave is obtained; based on the DC photovoltaic voltage and current, the battery current control value is obtained; based on the DC photovoltaic voltage and energy storage battery voltage, the asymmetric carrier wave is obtained. Based on the initial three-phase sinusoidal modulation wave and asymmetric carrier wave, the actual value of the battery current is obtained, and the difference between the actual value of the battery current and the battery current control value is calculated. The error is then iterated to obtain the zero-sequence component corresponding to the error being less than the error tolerance. The zero-sequence component is injected into the initial three-phase sinusoidal modulation wave to obtain the improved modulation wave; The improved modulation wave is intersected with the asymmetric carrier wave to obtain the converter PWM drive signal; The actual battery current value is obtained based on the initial three-phase sinusoidal modulation wave and the asymmetric carrier wave, including: Based on the initial three-phase sinusoidal modulation wave and asymmetric carrier boundary line To establish the relationship between battery current and modulation wave, ， in, This represents the average value of the battery current in each phase over one switching cycle. represent Three phases; The initial value for the zero-order component. This refers to the three-phase current on the AC side. The sum of the three-phase battery currents gives the actual battery current of the multi-port converter. , ； The actual battery current value is subtracted from the controlled battery current value. The resulting error is iterated to obtain the zero-sequence component when the error is less than the error tolerance. This includes... Step A: Determine if the difference between the current maximum and minimum values ​​is greater than the error tolerance. If it is, continue with the following steps using the current zero-order component; otherwise, use the current zero-order component as the final zero-order component. Here, the zero-order component is defined. , , These are the current iteration's maximum and minimum values, respectively. Step B: Combine the current initial value of the zero-sequence component with the initial three-phase sinusoidal modulation wave and the asymmetric carrier boundary line to obtain the actual value of the battery current. Step C: Obtain the error between the actual battery current value and the battery current control value. When the error is greater than 0, adjust the current... Update as the maximum value of the iteration; otherwise, update the current value. Update the minimum value of the iteration; return to step A.

2. The method as described in claim 1, characterized in that: Based on the three-phase AC voltage and current of the single-stage multi-port converter, the initial three-phase sinusoidal modulation wave is obtained, including: The three-phase voltage and current on the AC side of the single-stage multi-port converter were obtained by sampling. The initial three-phase sinusoidal modulation wave is obtained by performing dual closed-loop control on the three-phase voltage and current; Based on the DC-side photovoltaic voltage and current, the battery current control value is obtained, including: The DC-side photovoltaic voltage and current of the converter were obtained through sampling. The photovoltaic voltage and current are tracked by MPPT and DC-side power control to obtain the battery current control value.

3. The method as described in claim 1, characterized in that: Based on the DC-side photovoltaic voltage and the energy storage battery voltage, an asymmetric carrier wave is obtained, including: The asymmetric carrier boundary is obtained according to the following formula. , ， in, This refers to the photovoltaic voltage on the DC side of the converter. This refers to the voltage of the DC-side energy storage battery in the converter. Based on asymmetric carrier boundary Set the carrier range as , This results in an asymmetric carrier wave.

4. The method as described in claim 1, characterized in that: In step C, obtaining the error between the actual battery current value and the battery current control value includes, Constructing the error function ,in, This is the battery current control value. This represents the average value of the battery current in each phase over one switching cycle. represent Three phases.

5. The method as described in claim 1, characterized in that: The improved modulation wave is intersected with the asymmetric carrier wave to obtain the converter PWM drive signal, including: The improved modulation wave is combined with an asymmetric carrier wave, and the converter PWM drive signal is obtained by using the CBPWM modulation algorithm.

6. A control device based on a method for suppressing DC-side current ripple in a single-stage multi-port converter, comprising a memory, a processor, and a program stored in the memory; characterized in that: When the processor executes the program, it implements the method as described in any one of claims 1 to 5.

7. A storage medium having a program stored thereon; characterized in that: When the program is executed, it implements the method as described in any one of claims 1 to 5.

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