A multi-module energy storage converter system and a control method thereof

Abstract

This invention relates to the field of energy storage converter technology, and discloses a multi-module energy storage converter system and its control method. A sampling module is used to collect the current signal on the high-voltage side of the power conversion module. A control module is connected to each power conversion module and each sampling module, and is used to dynamically adjust the switching sequence output to the corresponding power conversion module based on the current signal collected by each sampling module. A support module is used to provide a low-impedance path for the high-frequency circulating current between the high-voltage sides of the power conversion modules, thereby suppressing the high-frequency circulating current component in the current signal collected by the sampling module. This invention, by connecting the sampling module in series on the bus between the power conversion module and the support module, and utilizing the support module to provide a low-impedance path for the circulating current between the high-voltage side modules, ensures that the sampled signal does not contain a circulating current component, avoiding interference from the circulating current to the control system and ensuring the stability of the closed-loop control.

Description

Technical Field

[0001] This invention relates to the field of energy storage converter technology, and more specifically to a multi-module energy storage converter system and its control method. Background Technology

[0002] In the field of residential energy storage and charging piles, multi-module parallel DC / DC converter topologies are commonly used to adapt to the needs of large-capacity battery cells and various output scenarios. Existing current sampling schemes mainly include battery-side sampling, high-voltage-side output sampling, and transformer secondary-side sampling.

[0003] In the aforementioned multi-module parallel energy storage converter system, the current sampling scheme directly affects the system's control accuracy and stability. Existing sampling methods mainly include: sampling the DC current after the electrolytic capacitor on the battery side, sampling the high-frequency current between each arm of the parallel full-bridge on the battery side and the capacitor, sampling the output current at the rear end of the high-voltage side bus support capacitor, and sampling by connecting a sensor in series on the secondary side of the transformer high-voltage winding.

[0004] Battery-side sampling faces challenges such as high cost due to low voltage and high current, complex printed circuit board (PCB) layout, and difficulty in distinguishing active current from high-frequency circulating current components between modules, resulting in poor control accuracy and inaccurate power calculation. While high-voltage-side output sampling offers high power calculation accuracy, it cannot monitor charging current during soft-start, easily leading to overcharging of the bus voltage. Furthermore, the coupling of high-frequency circulating current in the sampled signal can create positive feedback, exacerbating system oscillations. Transformer secondary-side sampling is affected by high-frequency magnetic flux changes and parasitic parameters, causing current waveform distortion, and its detection sensitivity is insufficient during soft-start. Summary of the Invention

[0005] In view of this, the present invention provides a multi-module energy storage converter system and its control method to solve the problem that the high-voltage side current sampling is easily affected by high-frequency circulating current interference, resulting in poor control accuracy in the prior art.

[0006] In a first aspect, the present invention provides a multi-module energy storage converter system, comprising: multiple power conversion modules, multiple sampling modules, multiple support modules, and a control module, wherein the low-voltage sides of each power conversion module are connected in parallel, and the high-voltage sides of each power conversion module are interconnected; each support module is connected in parallel between the positive and negative busbars of the high-voltage side of a power conversion module; each sampling module is connected in series on one of the busbars between a power conversion module and a support module, and the sampling module is used to collect the current signal of the high-voltage side of the power conversion module; the control module is connected to each power conversion module and each sampling module, and the control module is used to dynamically adjust the switching sequence output to the corresponding power conversion module based on the current signal collected by each sampling module; the support module is used to provide a low-impedance path for the high-frequency circulating current between the high-voltage sides of the power conversion modules, so as to suppress the high-frequency circulating current component in the current signal collected by the sampling module.

[0007] The multi-module energy storage converter system provided by this invention connects the sampling module in series on the bus between the power conversion module and the support module. Utilizing the support module's large-capacitance capacitor characteristic, its impedance to high-frequency signals is significantly lower than other paths, providing a dedicated low-impedance path for the high-frequency circulating current. This allows the high-frequency circulating current to preferentially flow through the support module rather than the sampling module, thereby decoupling the sampling signal from the high-frequency circulating current. This ensures the sampling signal accurately reflects the active current of each module, providing precise feedback to the controller and ensuring stable and reliable current closed-loop control. Simultaneously, the sampling node is located between the support module and the power conversion module. The common-mode voltage change at this node is gradual, reducing the requirements for isolation and anti-interference capabilities of the sampling circuit. Low-cost sampling components can be used for current detection, simplifying PCB layout and hardware design.

[0008] In one optional implementation, each power conversion module includes at least one low-voltage conversion unit, one high-voltage conversion unit, and one isolation unit. The input terminals of each low-voltage conversion unit are connected in parallel and then connected in parallel to the low-voltage sides of other power conversion modules. The output terminal of each low-voltage conversion unit is connected to the input terminal of the high-voltage conversion unit through the isolation unit. The output terminal of the high-voltage conversion unit is interconnected with the high-voltage sides of other power conversion modules. Both the low-voltage conversion unit and the high-voltage conversion unit are used to perform power conversion based on corresponding switching sequences.

[0009] In one optional implementation, the control module includes: an operational amplifier conditioning unit, a low-pass filter unit, and a main control unit. The operational amplifier conditioning unit is connected to each sampling module and the low-pass filter unit, and is used to perform proportional operation conditioning on the current signals collected by each sampling module. The low-pass filter unit is connected to the main control unit and is used to perform low-pass filtering on the conditioned current signals. The main control unit is connected to each power conversion module and is used to dynamically adjust the switching sequence output to the corresponding power conversion module based on the filtered current signals.

[0010] In one alternative implementation, the support module includes a support capacitor.

[0011] In one optional implementation, the system further includes: a plurality of absorption modules, wherein one end of each absorption module is connected to the bus between the corresponding power conversion module and the sampling module, and the other end is connected to the bus between the corresponding power conversion module and the support module. The absorption module is used to absorb the high-frequency ripple on the high-voltage side of the power conversion module.

[0012] In one alternative implementation, the absorption module includes an absorption capacitor.

[0013] In one optional implementation, the system further includes: multiple series drive switches and multiple parallel drive switches, wherein the high-voltage sides of each power conversion module are connected through the series drive switches and the parallel drive switches; each series drive switch and each parallel drive switch is used to switch the switch state based on the drive signal of the control module, so that the multi-module energy storage converter system outputs different levels of DC bus voltage.

[0014] The multi-module energy storage converter system provided by this invention, by setting series and parallel drive switches and controlling them under the control module, can flexibly switch the connection state between the high-voltage sides of each power conversion module according to the application scenario, realize the free reconfiguration of high voltage and low voltage, adapt to different load types, and improve the versatility and scenario adaptability of the system. At the same time, the switching process is coordinated with the current closed-loop control of the control module to ensure that the sampled signal does not contain circulating current components before and after the output mode switching, ensuring that the system can operate stably in different working modes.

[0015] Secondly, the present invention provides a control method for a multi-module energy storage converter system, applied to the control module of the multi-module energy storage converter system of the first aspect above or any corresponding embodiment thereof. The method includes: acquiring current signals collected by each sampling module; comparing the current signals with a reference current to obtain an error signal; and generating a switching sequence of the corresponding power conversion module after compensating and adjusting the error signal.

[0016] The control method for a multi-module energy storage converter system provided by this invention acquires a sampling signal on the bus connected in series between the power conversion module and the support module. This sampling signal naturally does not contain a circulating current component because the support module provides a low-impedance path for the high-frequency circulating current. This ensures that the error signal accurately reflects the active current deviation of each module. The switching sequence generated by compensating and adjusting based on this error signal can precisely control the output current of each power conversion module, avoiding the control oscillation problem caused by circulating current coupling in traditional schemes, and ensuring the stability and reliability of the closed-loop control system. At the same time, this method can independently adjust each module and is easily extended to a multi-module parallel system to achieve precise control and protection at the module level.

[0017] In one optional implementation, the process of obtaining an error signal by comparing the current signal with a reference current includes: subtracting the current signal collected by each sampling module from the corresponding reference current to obtain the corresponding current error signal.

[0018] In one optional implementation, the process of generating a switching sequence for the corresponding power conversion module after compensating and adjusting the error signal includes: performing proportional-integral adjustment on the error signal and outputting a modulation signal for the corresponding power conversion module; and performing pulse width modulation and filtering on the modulation signal to generate a switching sequence for the corresponding power conversion module. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a first configuration diagram of a multi-module energy storage converter system according to an embodiment of the present invention; Figure 2 This is a second configuration diagram of a multi-module energy storage converter system according to an embodiment of the present invention; Figure 3 This is a composition diagram of the control module according to an embodiment of the present invention; Figure 4 This is a detailed circuit diagram of a multi-module energy storage converter system according to an embodiment of the present invention; Figure 5 This is a high-frequency circulating current path diagram of a multi-module energy storage converter system according to an embodiment of the present invention; Figure 6 This is a flowchart illustrating the control method of a multi-module energy storage converter system according to an embodiment of the present invention; Figure 7This is a schematic diagram of the control strategy of the control module according to an embodiment of the present invention; Figure 8 This is a composition diagram of the control device for a multi-module energy storage converter system according to an embodiment of the present invention; Figure 9 This is a schematic diagram of the hardware structure of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] It is understood that before using the technical solutions disclosed in the various embodiments of the present invention, users should be informed of the types, scope of use, and usage scenarios of the personal information involved in the present invention and their authorization should be obtained in accordance with relevant laws and regulations through appropriate means.

[0023] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0024] Under the same capacity requirements, large-capacity cells exhibit lower total series voltage and higher output current compared to small-capacity cells. For this application, a parallel DC-DC topology is often used, such as multiple full-bridge DC-DC converters connected in parallel on the low-voltage side and a single full-bridge structure on the high-voltage side, or multiple DC-DC converters connected in parallel to the same battery bank. Furthermore, to adapt to different output scenarios, the high and low output voltages on the high-voltage side are reconfigured according to the paired single-phase or three-phase inverter to meet the voltage bus range required by the single-phase or three-phase inverter. For this application, a multi-independent DC-DC topology is often used. The voltage across the battery side (BAT+~BAT-) is relatively low, and each independent bus capacitor is connected in series and parallel to the total output (VBUS+~VBUS-) through a controllable switching device.

[0025] This embodiment provides a multi-module energy storage converter system, such as Figure 1As shown, the system includes: multiple power conversion modules 1, multiple sampling modules 2, multiple support modules 3, and a control module 4. The low-voltage sides of each power conversion module 1 are connected in parallel, and the high-voltage sides of each power conversion module 1 are interconnected. Each support module 3 is connected in parallel between the positive and negative busbars of the high-voltage side of a power conversion module 1. Each sampling module 2 is connected in series on one of the busbars between a power conversion module 1 and a support module 3. The sampling module 2 is used to acquire the current signal from the high-voltage side of the power conversion module 1. The support module 3 is used to provide a low-impedance path for the high-frequency circulating current between the high-voltage sides of the power conversion modules 1, thereby suppressing the high-frequency circulating current component in the current signal acquired by the sampling module 2.

[0026] For example, Figure 1 Taking two power conversion modules 1 as an example, the number of sampling modules 2 and support modules 3 matches the number of power conversion modules 1.

[0027] Specifically, Figure 1 In this configuration, multiple power conversion modules 1 are connected in parallel on their low-voltage sides and interconnected on their high-voltage sides, forming a multi-module parallel structure. A support module 3 is connected in parallel between the positive and negative buses on the high-voltage side of each power conversion module 1. This support module 3 can use large-capacitance components, utilizing their low impedance to high-frequency signals to create a dedicated flow loop with significantly lower impedance than other paths for high-frequency circulating current. A sampling module 2 is connected in series on one of the buses between each power conversion module 1 and its corresponding support module 3 to collect the current signal on the high-voltage side of that power conversion module 1. When the high-voltage sides of each power conversion module 1 are interconnected, the high-frequency circulating current generated between the modules flows along the impedance path. Since the impedance of the support module 3 is much lower than other paths, the high-frequency circulating current preferentially flows through the support module 3. The sampling module 2, connected in series on the bus between the power conversion module 1 and the support module 3, is located outside the circulating current path. Therefore, the current signal collected by the sampling module 2 does not contain the high-frequency circulating current component and only reflects the active current of the power conversion module 1, providing accurate feedback to the control module 4.

[0028] Optionally, Figure 1 In this system, the high-voltage sides of each power conversion module 1 are interconnected through a series drive switch K1 and a parallel drive switch (K2, K3). When the series drive switch is closed, the high-voltage sides of each power conversion module 1 are connected in series, and when the parallel drive switch is closed, the high-voltage sides of each power conversion module 1 are connected in parallel. By switching the state of each drive switch, the system can flexibly output different levels of DC bus voltage, such as the bus voltage corresponding to a single phase or a three-phase phase, 350V-550V for single phase and 700-950V for three phase, to adapt to different application scenarios.

[0029] Figure 1In this system, the control module 4 is connected to each power conversion module 1 and each sampling module 2. The control module 4 is used to dynamically adjust the switching sequence output to the corresponding power conversion module 1 based on the current signal collected by each sampling module 2.

[0030] Specifically, Figure 1 In this system, sampling module 2 is connected in series on the bus between power conversion module 1 and support module 3. Since support module 3 provides a low-impedance path for high-frequency circulating current, the current signal acquired by sampling module 2 does not contain high-frequency circulating current components, reflecting only the active current of power conversion module 1. After acquiring the current signals from each sampling module 2, control module 4 compares them with a preset reference current to obtain an error signal. This error signal is then compensated using proportional-integral (PI) and other methods to generate a corresponding modulation signal. Finally, after pulse width modulation, a switching sequence is formed and output to the corresponding power conversion module 1 to adjust its output current. Because the feedback signal does not contain circulating current components, the closed-loop regulation of control module 4 is not affected by circulating current interference, avoiding the positive feedback oscillation problem caused by circulating current coupling in traditional schemes. This ensures stable output current and good current sharing effect for each power conversion module 1, resulting in reliable system operation.

[0031] The multi-module energy storage converter system provided in this embodiment connects the sampling module in series on the bus between the power conversion module and the support module. Utilizing the support module's large-capacitance capacitor characteristic, its impedance to high-frequency signals is significantly lower than other paths, providing a dedicated low-impedance path for the high-frequency circulating current. This allows the high-frequency circulating current to preferentially flow through the support module rather than the sampling module, thereby decoupling the sampling signal from the high-frequency circulating current. This ensures the sampling signal accurately reflects the active current of each module, providing precise feedback to the controller and ensuring stable and reliable current closed-loop control. Simultaneously, the sampling node is located between the support module and the power conversion module. The common-mode voltage change at this node is gradual, reducing the requirements for isolation and anti-interference capabilities of the sampling circuit. Low-cost sampling components can be used for current detection, simplifying PCB layout and hardware design.

[0032] In some alternative implementations, such as Figure 2 As shown, each power conversion module 1 includes at least one low-voltage conversion unit 11, a high-voltage conversion unit 12, and an isolation unit 13. The input terminals of each low-voltage conversion unit 11 are connected in parallel and then connected in parallel to the low-voltage side of other power conversion modules 1. The output terminal of each low-voltage conversion unit 11 is connected to the input terminal of the high-voltage conversion unit 12 through the isolation unit 13. The output terminal of the high-voltage conversion unit 12 is interconnected with the high-voltage side of other power conversion modules 1. Both the low-voltage conversion unit 11 and the high-voltage conversion unit 12 are used for power conversion based on corresponding switching sequences.

[0033] Specifically, Figure 2In this system, control module 4 is connected to each low-voltage conversion unit 11 and high-voltage conversion unit 12, sending the switching sequence to the control terminals of the corresponding low-voltage conversion unit 11 and high-voltage conversion unit 12. The input terminals of each low-voltage conversion unit 11 are connected in parallel to the low-voltage side of other power conversion modules 1, sharing the same battery cell to achieve current shunting on the low-voltage side and reduce the current stress on individual modules. The output terminals of each low-voltage conversion unit 11 are connected to the input terminals of the high-voltage conversion unit 12 through isolation unit 13. Isolation unit 13 provides electrical isolation and energy transmission, ensuring system safety and reliability. The output terminals of the high-voltage conversion units 12 are interconnected with the high-voltage sides of other power conversion modules 1, allowing for series or parallel output as needed. Both low-voltage conversion units 11 and high-voltage conversion units 12 are equipped with switching devices that receive the corresponding switching sequences output by control module 4, performing high-frequency switching based on the switching sequences to achieve energy conversion. The low-voltage conversion unit 11 converts the DC power supplied by the battery into high-frequency AC power, which is then transmitted to the high-voltage conversion unit 12 via the isolation unit 13. The high-voltage conversion unit 12 then converts the high-frequency AC power into the required DC power and outputs it to the load, thus completing the transfer and conversion of energy from the low-voltage side to the high-voltage side.

[0034] In some alternative implementations, such as Figure 3 As shown, the control module 4 includes: an operational amplifier conditioning unit 41, a low-pass filter unit 42, and a main control unit 43. The operational amplifier conditioning unit 41 is connected to each sampling module 2 and the low-pass filter unit 42, and is used to perform proportional operation conditioning on the current signals collected by each sampling module 2. The low-pass filter unit 42 is connected to the main control unit 43, and is used to perform low-pass filtering on the conditioned current signals. The main control unit 43 is connected to each power conversion module 1, and is used to dynamically adjust the switching sequence output to the corresponding power conversion module 1 based on the filtered current signals.

[0035] Specifically, the operational amplifier conditioning unit 41 is connected to each sampling module 2 and the low-pass filter unit 42, receiving the current signal collected by the sampling modules 2. Since the sampling modules 2 are connected in series on the bus between the power conversion module 1 and the support module 3, the current signal they collect no longer contains high-frequency circulating current components and only reflects the active current. The operational amplifier conditioning unit 41 performs proportional operation conditioning on this signal, amplifying the weak signal to an amplitude range suitable for subsequent processing. The low-pass filter unit 42 is connected to the main control unit 43, further low-pass filtering the conditioned current signal to filter out any residual high-frequency switching noise, ensuring that the feedback signal entering the main control unit 43 is pure and smooth. The main control unit 43 is connected to each power conversion module 1, and dynamically adjusts the switching sequence output to the corresponding power conversion module 1 based on the comparison result between the filtered current signal and the reference current. Since the feedback signal does not contain circulating current components, the closed-loop regulation of the main control unit 43 is precise and stable, avoiding the control oscillation problem caused by circulating current coupling in traditional schemes, ensuring that the output current of each power conversion module 1 accurately follows the given value, achieving excellent current sharing effect and dynamic response.

[0036] In some alternative implementations, such as Figure 4 As shown, it also includes: multiple absorption modules, wherein the support module includes: support capacitors (Ce1, Ce2), and the absorption module includes: absorption capacitors (Cf1, Cf2). One end of each absorption capacitor is connected to the bus between the corresponding power conversion module 1 and the sampling module 2, and the other end is connected to the bus between the corresponding power conversion module 1 and the support capacitor. The absorption capacitor is used to absorb the high-frequency ripple on the high-voltage side of the power conversion module 1.

[0037] Specifically, refer to Figure 4 and Figure 5Sampling module 2 is connected in series at the connection point between the absorption capacitor and the support capacitor. The absorption capacitor has a small capacitance and excellent high-frequency characteristics. It is used to absorb the high-frequency switching ripple generated by the switching of the high-voltage side switching devices of power conversion module 1, so that the common-mode voltage change at the sampling node is smooth and there is no large dv / dt change. This greatly reduces the isolation difficulty of the sampling signal and allows for current detection using low-cost sampling elements. The support capacitor has a large capacitance and its impedance characteristic is 1 / (j*w*Ce), while the impedance characteristic of the absorption capacitor is 1 / (j*w*Cf). Since the capacitance of the support capacitor is much larger than that of the absorption capacitor, the impedance of the support capacitor is much smaller than that of the absorption capacitor. This provides a low-impedance path for the high-frequency circulating current (Ic1#, Ic2#) between the high-voltage sides of power conversion module 1, causing the high-frequency circulating current to flow preferentially through the support capacitor rather than sampling module 2. Sampling module 2 is connected in series at the connection point between the absorption capacitor and the support capacitor, located outside the circulating current path. Therefore, the acquired current signals (Io1#, Io2#) do not contain high-frequency circulating current components, reflecting only the active current. Simultaneously, the support capacitor acts as a bus voltage support when a sudden load is applied, ensuring stable dynamic response of the system. Thus, the inner current loop will not amplify minute high-frequency circulating currents that could cause system oscillations, achieving electrical isolation between the sampling signal and the high-frequency circulating current, ensuring stable and reliable closed-loop control.

[0038] In some alternative implementations, such as Figure 4 As shown, it also includes: multiple series drive switches K1 and multiple parallel drive switches (K2, K3), wherein the high-voltage sides of each power conversion module are connected through series drive switches and parallel drive switches; each series drive switch and each parallel drive switch is used to switch the switch state based on the drive signal of the control module, so that the multi-module energy storage converter system outputs different levels of DC bus voltage.

[0039] Specifically, Figure 4In this system, when the system needs to adapt to the bus voltage level required by a single-phase inverter (e.g., requiring a low-voltage DC bus voltage of 350V-550V), the control module 4 outputs a drive signal to close the parallel drive switches K2 and K3 and open the series drive switch K1. The high-voltage side output terminals of each power conversion module 1 are connected in parallel to jointly output the voltage range required for a single-phase inverter, meeting the needs of single-phase loads or single-phase grid connection. When the system needs to adapt to the bus voltage level required by a three-phase inverter (e.g., requiring a high-voltage DC bus voltage of 700V-950V), the control module 4 outputs a drive signal to close the series drive switch K1 and open the parallel drive switches K2 and K3. The high-voltage side output terminals of each power conversion module 1 are connected in series to the DC bus of the three-phase inverter, providing the required high bus voltage for the three-phase inverter. Through the flexible switching of the series and parallel drive switches by the control module 4, the system can be freely reconfigured between high and low voltage without changing the hardware topology, greatly improving the system's adaptability to different scenarios. Meanwhile, this switching process works in conjunction with the current sampling of sampling module 2 and the circulating current suppression function of support module 3 to ensure that the sampled signal does not contain high-frequency circulating current components in different output modes, thus ensuring that the system can achieve stable closed-loop control in single-phase or three-phase operating modes.

[0040] Optionally, Figure 4 In this process, each drive switch can be a relay, contactor, semiconductor switching device, or a combination thereof.

[0041] This embodiment provides a control method for a multi-module energy storage converter system, applicable to the control module of a multi-module energy storage converter system as described in the above embodiment or any corresponding implementation, such as... Figure 6 As shown, the method includes: Step S1: Acquire the current signals collected by each sampling module.

[0042] Specifically, the sampling module is connected in series on the bus between the power conversion module and the support module. Since the support module provides a low impedance path for the high-frequency circulating current, the sampling signal does not contain the high-frequency circulating current component and only reflects the active current of each power conversion module, providing accurate feedback for closed-loop control.

[0043] Step S2: After comparing the current signal with the reference current, the error signal is obtained.

[0044] refer to Figure 7 The process of obtaining an error signal by comparing the current signal with the reference current Iref includes: subtracting the current signal collected by each sampling module from the corresponding reference current to obtain the corresponding current error signal.

[0045] Specifically, the Io1#_1 obtained after the current signal Io1# is conditioned by an operational amplifier and low-pass filtered is compared with the reference current Iref to obtain the current error signal of each power conversion module. This error signal truly reflects the deviation between the actual output current and the target current.

[0046] Step S3: After compensating and adjusting the error signal, generate the switching sequence of the corresponding power conversion module.

[0047] The process of generating the switching sequence of the corresponding power conversion module after compensating and adjusting the error signal includes: Step S31: After performing proportional-integral adjustment on the error signal, output the modulation signal corresponding to the power conversion module.

[0048] Step S32: After pulse width modulation and filtering of the modulation signal, the switching sequence of the corresponding power conversion module is generated.

[0049] Specifically, the error signal passes through a proportional-integral (PI) regulator. The proportional element quickly responds to the deviation, and the integral element eliminates the steady-state error, enabling the modulation signal to accurately compensate for the current deviation. Then, through a KPWM stage, the modulation signal is compared with the carrier wave to generate a pulse sequence with an adjustable duty cycle. This pulse width modulation signal then drives the switching devices in the power conversion module to turn on and off, in the inductor (corresponding to...) Figure 7 A continuous output current is generated in the 1 / sL link (in the circuit), thereby dynamically adjusting the output current of each module to form a complete current closed-loop control loop. Since the sampled signal does not contain circulating current components, the error signal truly reflects the active current deviation. The proportional-integral regulation, pulse width modulation, and filtering links are not affected by circulating current interference, avoiding the positive feedback oscillation problem caused by circulating current coupling in traditional schemes. This ensures the stability and dynamic response performance of the closed-loop control. Each module can be adjusted independently, making it easy to achieve module-level current sharing and protection.

[0050] The control method for the multi-module energy storage converter system provided in this embodiment acquires a sampling signal on the bus connected in series between the power conversion module and the support module. This sampling signal naturally does not contain a circulating current component because the support module provides a low-impedance path for the high-frequency circulating current. This ensures that the error signal accurately reflects the active current deviation of each module. The switching sequence generated by compensating and adjusting based on this error signal can accurately control the output current of each power conversion module, avoiding the control oscillation problem caused by circulating current coupling in traditional schemes, and ensuring the stability and reliability of the closed-loop control system. At the same time, this method can independently adjust each module and is easily extended to a multi-module parallel system to achieve precise module-level control and protection.

[0051] This embodiment also provides a control device for a multi-module energy storage converter system. This device is used to implement the above embodiments and preferred embodiments, and details already described will not be repeated. As used below, the term "module" can be a combination of software and / or hardware that performs a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0052] This embodiment provides a control device for a multi-module energy storage converter system, such as... Figure 8 As shown, it includes: The acquisition module 801 is used to acquire the current signals collected by each sampling module.

[0053] The comparison module 802 is used to compare the current signal with the reference current to obtain an error signal.

[0054] The compensation module 803 is used to compensate and adjust the error signal and then generate the corresponding switching sequence of the power conversion module.

[0055] The control device for the multi-module energy storage converter system provided in this embodiment of the invention can execute the method provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects for executing the method. Further functional descriptions of the various modules and units are the same as those in the corresponding embodiments described above, and will not be repeated here. Figure 9 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention.

[0056] The following is a detailed reference. Figure 9 The diagram illustrates a structural schematic suitable for implementing an electronic device according to embodiments of the present invention. The electronic device may include a processor (e.g., a central processing unit, graphics processor, etc.) 001, which can perform various appropriate actions and processes according to a program stored in read-only memory (ROM) 002 or a program loaded from memory 008 into random access memory (RAM) 003. The RAM 003 also stores various programs and data required for the operation of the electronic device. The processor 001, ROM 002, and RAM 003 are interconnected via bus 004. An input / output (I / O) interface 005 is also connected to bus 004.

[0057] Typically, the following devices can be connected to I / O interface 005: input devices 006 including, for example, touchscreens, touchpads, keyboards, mice, cameras, microphones, accelerometers, gyroscopes, etc.; output devices 007 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; memory devices 008 including, for example, magnetic tapes, hard disks, etc.; and communication devices 009. Communication device 009 allows electronic devices to exchange data via wireless or wired communication with other devices. Although Figure 9 Electronic devices with various devices are shown, but it should be understood that it is not required to implement or have all of the devices shown, and more or fewer devices may be implemented or have instead.

[0058] In particular, according to embodiments of the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program carried on a non-transitory computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication device 009, or installed from memory 008, or installed from ROM 002. When the computer program is executed by processor 001, it performs the functions defined in the methods of the embodiments of the present invention.

[0059] Figure 9 The electronic device shown is merely an example and should not be construed as limiting the functionality and scope of use of the embodiments of the present invention.

[0060] This invention also provides a computer-readable storage medium. The methods described above according to embodiments of the invention can be implemented in hardware or firmware, or implemented as computer code that can be recorded on a storage medium, or implemented as computer code downloaded via a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and then stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code, which, when accessed and executed by the computer, processor, or hardware, implements the methods shown in the above embodiments.

[0061] A portion of this invention can be applied as a computer program product, such as computer program instructions, which, when executed by a computer, can invoke or provide the methods and / or technical solutions according to the invention through the operation of the computer. Those skilled in the art will understand that the forms in which computer program instructions exist in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Correspondingly, the ways in which computer program instructions are executed by a computer include, but are not limited to: the computer directly executing the instructions, or the computer compiling the instructions and then executing the corresponding compiled program, or the computer reading and executing the instructions, or the computer reading and installing the instructions and then executing the corresponding installed program. Here, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible to a computer.

[0062] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A multi-module energy storage inverter system, characterized by, include: Multiple power conversion modules, multiple sampling modules, multiple support modules, and control modules, among which, The low-voltage side of each power conversion module is connected in parallel, and the high-voltage side of each power conversion module is connected to each other. Each of the support modules is connected in parallel between the positive and negative busbars on the high-voltage side of one of the power conversion modules; Each of the sampling modules is connected in series on one of the busbars between a power conversion module and a support module. The sampling module is used to collect the current signal on the high-voltage side of the power conversion module. The control module is connected to each of the power conversion modules and each of the sampling modules. The control module is used to dynamically adjust the switching sequence output to the corresponding power conversion module based on the current signal collected by each sampling module. The support module is used to provide a low-impedance path for the high-frequency circulating current between the high-voltage side of the power conversion module, so as to suppress the high-frequency circulating current component in the current signal acquired by the sampling module.

2. The multi-module energy storage inverter system of claim 1, wherein, Each of the power conversion modules includes: at least one low-voltage conversion unit, one high-voltage conversion unit, and one isolation unit, wherein... The input terminals of each low-voltage conversion unit are connected in parallel and then connected in parallel to the low-voltage side of other power conversion modules. The output terminal of each low-voltage conversion unit is connected to the input terminal of the high-voltage conversion unit through the isolation unit. The output terminal of the high-voltage conversion unit is interconnected with the high-voltage side of other power conversion modules; Both the low-voltage conversion unit and the high-voltage conversion unit are used to perform power conversion based on the corresponding switching sequence.

3. The multi-module energy storage inverter system of claim 1, wherein, The control module includes: an operational amplifier conditioning unit, a low-pass filter unit, and a main control unit, wherein... The operational amplifier conditioning unit is connected to each of the sampling modules and the low-pass filter unit. The operational amplifier conditioning unit is used to perform proportional operation conditioning on the current signals collected by each sampling module. The low-pass filter unit is connected to the main control unit, and the low-pass filter unit is used to perform low-pass filtering on the conditioned current signal. The main control unit is connected to each of the power conversion modules, and the main control unit is used to dynamically adjust the switching sequence output to the corresponding power conversion module based on the filtered current signal.

4. The multi-module energy storage inverter system of claim 1, wherein, The support module includes: a support capacitor.

5. The multi-module energy storage converter system according to claim 1, characterized in that, Also includes: Multiple absorption modules, among which, One end of each absorption module is connected to the bus between the corresponding power conversion module and the sampling module, and the other end is connected to the bus between the corresponding power conversion module and the support module. The absorption module is used to absorb the high-frequency ripple on the high-voltage side of the power conversion module.

6. The multi-module energy storage converter system according to claim 5, characterized in that, The absorption module includes an absorption capacitor.

7. The multi-module energy storage converter system according to claim 1, characterized in that, Also includes: Multiple series drive switches and multiple parallel drive switches, among which, The high-voltage sides of each of the power conversion modules are connected through the series drive switch and the parallel drive switch; Each of the series drive switches and each of the parallel drive switches are used to switch the switch state based on the drive signal of the control module, so that the multi-module energy storage converter system outputs different levels of DC bus voltage.

8. A control method for a multi-module energy storage converter system, characterized in that, The method, applied to a control module in a multi-module energy storage converter system according to any one of claims 1 to 7, comprises: Acquire the current signals collected by each sampling module; The error signal is obtained by comparing the current signal with the reference current. After compensating and adjusting the error signal, a switching sequence for the corresponding power conversion module is generated.

9. The control method for the multi-module energy storage converter system according to claim 8, characterized in that, The process of comparing the current signal with the reference current to obtain the error signal includes: The current error signal is obtained by subtracting the current signal collected by each sampling module from the corresponding reference current.

10. The control method for the multi-module energy storage converter system according to claim 8, characterized in that, The process of generating the switching sequence of the corresponding power conversion module after compensating and adjusting the error signal includes: After performing proportional-integral adjustment on the error signal, the corresponding modulation signal of the power conversion module is output. After pulse width modulation and filtering of the modulated signal, the switching sequence of the corresponding power conversion module is generated.

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