Bus soft start control method, circuit and device of energy storage inverter system

Abstract

The invention provides a bus soft start control method, circuit and device of an energy storage inverter system. The energy storage inverter system comprises a first bus connected between a photovoltaic module and an inverter module and a second bus connected between an energy storage module and the inverter module, and a resonant conversion module is connected between the energy storage module and the second bus; the method comprises the following steps: pre-charging the second bus before the resonant conversion module is started; and after the pre-charging of the second bus is finished, the resonant conversion module is started. According to the scheme, the resonant conversion module is controlled to be started after the second bus is pre-charged, so that the situation that the difference value between the output voltage of the resonant conversion module and the voltage of the second bus is too large, so that the impact overcurrent is too large, and the energy storage inverter system is damaged is avoided.

Description

Technical Field

[0001] This application relates to the field of control of energy storage inverter systems, and in particular to a bus soft start control method, circuit and device for energy storage inverter systems. Background Technology

[0002] Some energy storage inverter systems require connection to energy storage batteries for charging and discharging. The energy storage battery side typically employs a two-stage topology consisting of a resonant converter and a DC-DC converter. The bus connected to the resonant converter has capacitance; directly turning on the resonant converter can result in an excessively large output start-up current, potentially damaging components in the energy storage inverter system.

[0003] Currently, some solutions typically employ slow-start strategies to achieve a gradual start-up of the resonant converter; however, this approach still cannot prevent damage to the energy storage inverter system from excessive inrush current. Summary of the Invention

[0004] This application provides a bus soft-start control method, circuit, and device for an energy storage inverter system to avoid damage to the energy storage inverter system caused by excessive inrush current.

[0005] In a first aspect, this application provides a bus soft-start control method for an energy storage inverter system. The energy storage inverter system includes a first bus connected between a photovoltaic module and an inverter module, a second bus connected between an energy storage module and an inverter module, and a resonant converter module connected between the energy storage module and the second bus. The method includes: pre-charging the second bus before the resonant converter module is turned on; and turning on the resonant converter module after the pre-charging of the second bus is completed.

[0006] In one possible implementation, the second bus is pre-charged before the resonant converter module is turned on, including: after power-on, acquiring the voltage of the first bus; when the voltage of the first bus is greater than a first preset value, pre-charging the second bus based on the voltage of the first bus; the first preset value is obtained based on the voltage gain of the resonant converter module and the voltage of the energy storage module; when the voltage of the first bus is not greater than the first preset value, pre-charging the second bus based on the voltage provided by the auxiliary source.

[0007] In one possible implementation, when the second bus is pre-charged based on the voltage provided by the auxiliary source, the resonant conversion module is activated after the pre-charging of the second bus is completed. Specifically, this includes: activating the conversion module after the pre-charging of the second bus is completed to perform voltage equalization on the first bus and the second bus; and activating the resonant conversion module after the equalization is completed.

[0008] In one possible implementation, activating the conversion module to perform voltage balancing on the first bus and the second bus includes: calculating a first absolute value of the difference between the voltage of the second bus after pre-charging and the target pre-charging voltage; if the first absolute value is less than a preset error value, activating the conversion module to charge the first bus through the conversion module until the voltage of the first bus reaches a second preset value; the second preset value is obtained based on the first preset value and a preset voltage margin; calculating a second absolute value of the difference between the voltage of the first bus after charging and the second preset value; if the second absolute value is less than the preset error value, the first bus charges the second bus through the conversion module until the voltage of the second bus reaches the first preset value.

[0009] In one possible implementation, after the equalization is completed and the resonant converter module is turned on, the following steps are also included: calculating the third absolute value of the difference between the voltage of the first bus and the voltage of the second bus after the equalization is completed; if the third absolute value is less than a preset error value, then the electrical connection between the first bus and the inverter module is turned on.

[0010] In one possible implementation, the method further includes: if the first absolute value is not less than the preset error value, the second absolute value is not less than the preset error value, and the third absolute value is not less than the preset error value, a pre-charge error is reported.

[0011] In one possible implementation, the method further includes: when the second bus is pre-charged based on the voltage of the first bus, the pre-charging of the second bus is determined to be completed when the voltage of the second bus reaches a first preset value; when the second bus is pre-charged based on the voltage provided by the auxiliary source, the pre-charging of the second bus is determined to be completed when the voltage of the second bus reaches a third preset value; the third preset value is obtained based on the voltage of the auxiliary source and the voltage of the first bus after power-on.

[0012] Secondly, this application provides a bus soft-start control circuit for an energy storage inverter system, comprising: a first bus, a second bus, a resonant converter module, and a conversion module; one end of the first bus is used to connect to a photovoltaic module, and the other end of the first bus is used to connect to an inverter module; one end of the second bus is connected to one end of the resonant converter module, and the other end of the second bus is used to connect to the inverter module; the other end of the resonant converter module is used to connect to an energy storage module; the conversion module is connected between the first bus and the second bus, wherein the conversion module is turned on before the resonant converter module is turned on to precharge the second bus; wherein the resonant converter module is turned on after the precharging of the second bus is completed.

[0013] In one possible implementation, the circuit further includes: a selection module; the selection module includes a first terminal, a second terminal, and a third terminal; the first terminal is connected to the inverter module and the auxiliary power source, the second terminal is connected to the other end of the first bus, and the third terminal is connected to the other end of the second bus; the selection module is used to connect the first terminal to the second terminal after power-on, when the voltage of the first bus is greater than a first preset value, so as to conduct the conductive path between the other end of the first bus and the inverter module, and supply power to the inverter module.

[0014] In one possible implementation, a conversion module is configured to be activated after the first end of the selection module is connected to the second end, so as to perform voltage equalization on the first bus and the second bus and precharge the second bus.

[0015] In one possible implementation, the resonant converter module is used to be turned on after the pre-charging of the second bus is completed.

[0016] In one possible implementation, the circuit further includes: an auxiliary power source; the selection module is also configured to connect the first terminal to the third terminal when the voltage of the first bus is not greater than a first preset value, so as to precharge the second bus through the auxiliary power source.

[0017] In one possible implementation, the conversion module is also used to turn on after the second bus has been pre-charged by the auxiliary source, so as to perform voltage equalization of the first bus and the second bus by the conversion module.

[0018] In one possible implementation, the selection module includes a single-pole double-throw switch; the common terminal of the single-pole double-throw switch is connected as the first terminal to the auxiliary power source and the inverter module, the normally closed terminal of the single-pole double-throw switch is connected as the second terminal to the other end of the first bus, and the normally open terminal of the single-pole double-throw switch is connected as the third terminal to the other end of the second bus; when the voltage of the first bus is greater than a first preset value, the first terminal is connected to the second terminal; when the voltage of the first bus is not greater than the first preset value, the first terminal is connected to the third terminal.

[0019] In one possible implementation, the auxiliary power source includes an AC power supply and a battery; the AC power supply and the battery are respectively connected to the first terminal and the inverter module.

[0020] In one possible implementation, the circuit further includes: a first diode, a second diode, and a third diode; the first diode is disposed in the connection path between the AC power supply and the first terminal, the anode of the first diode is connected to the AC power supply, and the cathode of the first diode is connected to the first terminal; the second diode is disposed in the connection path between the battery and the first terminal, the anode of the second diode is connected to the battery, and the cathode of the second diode is connected to the first terminal; the anode of the third diode is connected to the photovoltaic module, and the cathode of the third diode is connected to one end of the first busbar.

[0021] In one possible implementation, the circuit further includes: a fourth diode and a first current limiting module; the positive terminal of the fourth diode is connected to the other end of the first bus, and the negative terminal of the fourth diode is connected to the first end of the first current limiting module; the second end of the first current limiting module is connected to the second end.

[0022] In one possible implementation, the circuit further includes: a second current limiting module;

[0023] The first end of the second current limiting module is connected to the third end, and the second end of the second current limiting module is connected to the second bus.

[0024] Thirdly, this application provides a bus soft-start control device for an energy storage inverter system. The energy storage inverter system includes a first bus connected between a photovoltaic module and an inverter module, and a second bus connected between an energy storage module and an inverter module. A resonant converter module is connected between the energy storage module and the second bus. The device includes: a pre-charge module for pre-charging the second bus before the resonant converter module is turned on; and an activation module for turning on the resonant converter module after the pre-charging of the second bus is completed.

[0025] Fourthly, embodiments of this application provide an electronic device, including: a memory and a processor;

[0026] The memory stores computer-executed instructions;

[0027] The processor executes computer execution instructions stored in the memory, causing the processor to perform the first aspect and / or various possible implementations of the first aspect as described above.

[0028] Fifthly, embodiments of this application provide a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the first aspect and / or various possible implementations of the first aspect.

[0029] Sixthly, embodiments of this application provide a computer program product, including a computer program that, when executed by a processor, implements the first aspect and / or various possible implementations of the first aspect.

[0030] This application provides a bus soft-start control method, circuit, and device for an energy storage inverter system. The energy storage inverter system includes a first bus connected between a photovoltaic module and an inverter module, and a second bus connected between the energy storage module and the inverter module. A resonant converter module is connected between the energy storage module and the second bus. By pre-charging the second bus before the resonant converter module is turned on, the voltage of the second bus connected to the resonant converter module is increased. After the pre-charging of the second bus is completed, the resonant converter module is then turned on. This avoids the risk of damage to the components of the energy storage inverter system caused by excessive inrush current during capacitor charging of the second bus after the resonant converter module is turned on. Attached Figure Description

[0031] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0032] Figure 1 An example of an energy storage inverter system architecture diagram;

[0033] Figure 2 An exemplary flowchart of a bus soft-start control method for an energy storage inverter system is shown.

[0034] Figure 3 This is a schematic diagram of the architecture of an example energy storage inverter system in this application;

[0035] Figure 4 An exemplary flowchart of a bus soft-start control method for an energy storage inverter system is shown.

[0036] Figure 5 An exemplary flowchart of a bus soft-start control method for an energy storage inverter system is shown.

[0037] Figure 6 An exemplary flowchart of a bus soft-start control method for an energy storage inverter system is shown.

[0038] Figure 7 This is a flowchart illustrating a bus soft-start control method for an energy storage inverter system, as an example of this application.

[0039] Figure 8 This is a schematic diagram of the bus soft-start control circuit of an energy storage inverter system as an example of this application.

[0040] Figure 9 An exemplary schematic diagram of a bus soft-start control device for an energy storage inverter system is shown.

[0041] Figure 10 The diagram above illustrates the structure of an electronic device.

[0042] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0043] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0044] It should be noted that the brief descriptions of terms in this application are only for the convenience of understanding the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise stated, these terms should be understood in their ordinary and common meaning. The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar or related objects or entities, and do not necessarily mean to limit a specific order or sequence, unless otherwise indicated. It should be understood that such terms can be used interchangeably where appropriate, for example, to be implemented in an order other than those given in the illustrations or descriptions of the embodiments of this application. The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application, are intended to be omnipresent but not exclusive. For example, a product or device that comprises a series of components is not necessarily limited to those components that are explicitly listed, but may include other components that are not explicitly listed or are inherent to such products or devices. The term "module" as used in this application refers to any known or subsequently developed hardware, software, firmware, artificial intelligence, fuzzy logic, or combination of hardware and / or software code capable of performing the functions associated with that element.

[0045] Some energy storage inverter systems require connection to low-voltage energy storage batteries for charging and discharging. The battery side of the energy storage unit typically employs a two-stage topology consisting of a resonant converter and a DC-DC converter, such as... Figure 1 As shown, Figure 1This is an example of an energy storage inverter system architecture. The resonant energy storage inverter system includes a photovoltaic module, a Maximum Power Point Tracking (MPPT) module, a large DC bus (with a large capacitance), an inverter module, an energy storage module, a resonant DC-DC converter, and a DC-DC converter. For the resonant DC-DC converter, during the first few switching cycles after startup, the resonant cavity line impedance is low, and the DC bus capacitance is large. The peak startup current of the resonant cavity may reach more than five times the normal operating current. Excessive startup current may damage the components of the energy storage inverter system.

[0046] Currently, some solutions typically employ soft-start strategies, such as variable frequency soft start, variable duty cycle soft start, and variable frequency + variable duty cycle soft start, to achieve a slow start-up of the resonant converter. However, in some cases, this approach may not completely prevent damage to the energy storage inverter system from excessive inrush current.

[0047] The bus soft-start control method, circuit, and device for an energy storage inverter system provided in this application aim to solve the above-mentioned technical problems of the prior art. The bus soft-start control method, circuit, and device for an energy storage inverter system provided in this application include a first bus connected between a photovoltaic module and an inverter module, and a second bus connected between an energy storage module and an inverter module. A resonant converter module is connected between the energy storage module and the second bus. By pre-charging the second bus before the resonant converter module is turned on, the voltage of the second bus connected to the resonant converter module is increased. After the pre-charging of the second bus is completed, the resonant converter module is then turned on. This avoids the risk of damage to various components of the energy storage inverter system caused by excessive inrush current when the capacitor of the second bus is charged after the resonant converter module is turned on.

[0048] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0049] Example 1

[0050] Figure 2 An exemplary flowchart illustrates a bus soft-start control method for an energy storage inverter system. The energy storage inverter system includes a first bus connected between a photovoltaic module and an inverter module, a second bus connected between an energy storage module and an inverter module, and a resonant converter module connected between the energy storage module and the second bus. The method includes:

[0051] Step 101: Before turning on the resonant converter module, pre-charge the second bus.

[0052] Step 102: After the pre-charging of the second busbar is completed, turn on the resonant conversion module.

[0053] Specifically, Figure 3 This is a schematic diagram of the architecture of an example energy storage inverter system of this application; as shown Figure 3 As shown, the complete architecture of the energy storage inverter system includes a photovoltaic module, an MPPT module, a first bus (equivalent to a large DC bus), an energy storage module, a second bus (equivalent to a small DC bus), a resonant converter module, a conversion module, and an inverter module. The first bus connects the photovoltaic module and the inverter module, the second bus connects the energy storage module and the inverter module (including the inverter module), and the resonant converter module connects the energy storage module and the second bus. The inverter module supplies power to the energy storage inverter system itself. For example, during the initial startup of the energy storage inverter system, the photovoltaic module's light intensity is weak. When the energy storage module needs to be activated for charging and discharging, to avoid generating a large voltage when the resonant converter module connected to the energy storage module is activated, resulting in a large voltage difference between the second bus and the energy storage module, causing excessive inrush current and damage to components of the energy storage inverter system, such as switching transistors, the second bus is first pre-charged until its voltage reaches the target value. After the pre-charging of the second bus is completed, the resonant converter module is activated to start the energy storage module's charging and discharging. For example, the purpose of pre-charging is because there is a capacitor on the second bus. If the voltage difference is too large, directly turning on the resonant converter to charge the capacitor would result in an excessive inrush current, damaging the devices. The capacitance of the first bus is greater than that of the second bus. In this example, by pre-charging the second bus, the voltage difference between the resonant converter module and the second bus is reduced after the pre-charging is completed, thus avoiding the impact of excessive current on the energy storage inverter system and preventing damage to the various devices in the energy storage inverter system.

[0054] Optional, Figure 4 An exemplary flowchart illustrates a bus soft-start control method for an energy storage inverter system; before the resonant converter module is turned on, the second bus is pre-charged, including:

[0055] Step 201: After power-on, obtain the voltage of the first bus;

[0056] Step 202: When the voltage of the first bus is greater than the first preset value, the second bus is pre-charged based on the voltage of the first bus; the first preset value is obtained based on the voltage gain of the resonant converter module and the voltage of the energy storage module.

[0057] Step 203: When the voltage of the first busbar is not greater than the first preset value, precharge the second busbar based on the voltage provided by the auxiliary source.

[0058] Specifically, after the energy storage inverter system is powered on, the voltage of the first bus after power-on is acquired. When the voltage of the first bus is greater than a first preset value, the second bus is pre-charged based on the voltage of the first bus. The first preset value is obtained based on the voltage gain of the resonant converter module and the voltage of the energy storage power supply. For example, the voltage of the first bus after power-on is represented as V. BUS1 The first preset value is represented as M×V BAT M is the voltage gain of the resonant converter module, V BAT The voltage of the energy storage module is used. When the voltage of the first bus is not greater than a first preset value, the second bus is pre-charged based on the voltage provided by the auxiliary power source. In this example, by determining whether the voltage of the first bus is greater than the preset value, different pre-charging strategies are selected to pre-charge the second bus. This avoids the impact of excessive current on the energy storage inverter system while improving the startup efficiency of the energy storage inverter system.

[0059] Optional, Figure 5 An exemplary flowchart illustrates a bus soft-start control method for an energy storage inverter system. When the second bus is pre-charged based on the voltage provided by the auxiliary source, the resonant converter module is activated after the pre-charging of the second bus is completed. Specifically, this includes:

[0060] Step 301: After the pre-charging of the second busbar is completed, the conversion module is turned on to perform voltage balancing on the first busbar and the second busbar.

[0061] Step 302: After the equalization is completed, turn on the resonance transformation module.

[0062] Specifically, when the voltage of the first bus is not greater than a preset value after power-on, the voltage provided by the auxiliary power source is used to pre-charge the second bus. After the pre-charging of the second bus is completed, the conversion module is turned on to equalize the voltages of the first and second buses. After the voltage equalization of the first and second buses is completed, the resonant conversion module is turned on. This further avoids excessive current generation caused by an excessive voltage difference between the first and second buses after the conversion module is turned on, which could damage the components of the energy storage inverter system.

[0063] Optional, Figure 6 An exemplary flowchart illustrates a bus soft-start control method for an energy storage inverter system; activating the conversion module to perform voltage balancing on the first and second buses includes:

[0064] Step 401: Calculate the first absolute value of the difference between the voltage of the second bus after pre-charging and the target voltage of pre-charging; if the first absolute value is less than the preset error value, then activate the conversion module so that the second bus charges the first bus through the conversion module until the voltage of the first bus reaches the second preset value; the second preset value is obtained based on the first preset value and the preset voltage margin.

[0065] Step 402: Calculate the second absolute value of the difference between the voltage of the first bus after charging and the second preset value. If the second absolute value is less than the preset error value, the first bus charges the second bus through the conversion module until the voltage of the second bus reaches the first preset value.

[0066] Specifically, firstly, the first absolute value of the difference between the sampled voltage value of the second bus after pre-charging and the target pre-charging voltage value for the second bus is calculated; if the first absolute value is less than a preset error value, the conversion module is activated; for example, the target pre-charging voltage value for the second bus is max(V BUS1 ,U1), where V BUS1 U1 is the voltage of the first bus after power-on, U2 is the voltage provided by the auxiliary power source, and the sampling voltage at the end of the pre-charge of the second bus is represented as V. bus1 If ABS(V) bus1 -max(V BUS1 ,U1)) <V 误差 , where V 误差 If a preset error value is specified, the conversion module is activated, allowing the second bus to charge the first bus via the conversion module. This causes the first bus voltage to increase until it reaches a second preset value. The second preset value is derived from the first preset value and a preset voltage margin. For example, the second preset value is represented as M*V. BAT +V 裕量 , where V 裕量 This represents the preset voltage margin, where M is the voltage gain of the resonant converter module. In practical applications, the preset voltage margin is set based on empirical values, and is generally greater than the preset error value. After charging the voltage of the first bus to the second preset value, the second absolute value of the difference between the charged voltage of the first bus and the second preset value is calculated again. If the second absolute value is less than the preset error value, i.e., ABS(V) BUS2 -M*V BAT -V 裕量 ) <V 误差 V BUS2This represents the sampled voltage value of the first bus after charging, with ABS indicating the calculation of the absolute value. Then, the first bus, through the conversion module, charges the second bus until its voltage reaches a first preset value. In practical applications, the voltage balancing process between the first and second buses is a pre-charging process of the first bus to the second bus. This completes the voltage balancing of the first and second buses, preventing excessive voltage difference between them, which could lead to excessive inrush current and damage to the energy storage inverter system.

[0067] Optionally, after the equalization is complete and the resonant transformation module is activated, the following may also be included:

[0068] After the equalization is completed, the third absolute value of the difference between the voltage of the first bus and the voltage of the second bus is calculated. If the third absolute value is less than the preset error value, the electrical connection between the first bus and the inverter module is turned on.

[0069] For example, after voltage balancing of the first bus and the second bus is completed, the third absolute value of the voltage difference between the first bus and the second bus after balancing is calculated. If the third absolute value is less than a preset error value, the electrical connection between the first bus and the inverter module is connected, and the first bus supplies power to the inverter module. For example, if ABS(V bus2 -V BUS3 ) <V 误差 Then the electrical connection between the first bus and the inverter module is established; where V bus2 V represents the voltage of the second bus after the equalization process is completed. BUS3 This indicates the voltage of the third bus after voltage equalization is complete. When the absolute value of the voltage difference between the first bus and the second bus after voltage equalization is determined to be less than a preset threshold, the electrical connection between the first bus and the inverter module is activated. When the light intensity of the photovoltaic module connected to the first bus is sufficiently strong, the photovoltaic module is connected to the first bus to supply power to the inverter module, reducing the power loss of the energy storage module.

[0070] Optionally, the method also includes:

[0071] If the first absolute value is not less than the preset error value, the second absolute value is not less than the preset error value, and the third absolute value is not less than the preset error value, a pre-charge error is reported.

[0072] Specifically, if the first absolute value, the second absolute value, and the third absolute value obtained from the aforementioned calculations are not less than the preset error value, a pre-charge error must be reported before proceeding to the next step. If the preset error value is not met, a pre-charge error is reported, and no operation is performed, awaiting maintenance; this further protects the energy storage inverter system and enhances its safety.

[0073] Optionally, the method also includes:

[0074] When the second bus is pre-charged based on the voltage of the first bus, the pre-charging of the second bus is determined to be completed when the voltage of the second bus reaches the first preset value.

[0075] When the second bus is pre-charged based on the voltage provided by the auxiliary source, the pre-charging of the second bus is determined to be completed when the voltage of the second bus reaches a third preset value; the third preset value is obtained based on the voltage of the auxiliary source and the voltage of the first bus after it is powered on.

[0076] Specifically, when the second bus is pre-charged based on the voltage of the first bus, the pre-charging of the second bus is considered complete when the voltage of the second bus reaches the aforementioned first preset value. When the second bus is pre-charged based on the voltage provided by the auxiliary power source, the pre-charging of the second bus is determined to be complete when the voltage of the second bus reaches the third preset value. The third preset value is obtained based on the voltage of the auxiliary power source and the voltage of the first bus after power-on, and is the aforementioned pre-charging target voltage value of the second bus, max(V). BUS1 U1).

[0077] Based on the examples above, Figure 7 This is a flowchart illustrating a bus soft-start control method for an energy storage inverter system, as exemplified in this application. Figure 7As shown, the system determines whether the voltage of the first bus after power-on is greater than a first preset value. If so, the conversion module is activated to raise the voltage of the second bus to the first preset value. It then determines whether the absolute value of the difference between the voltage sampling value of the second bus and the first preset value is less than a preset error value. If so, the resonant conversion module is activated, and the energy storage inverter system starts normal operation. If not, a pre-charge error is reported. If the voltage of the first bus after power-on is not greater than the first preset value, the auxiliary power source is activated to charge the second bus. The system then determines whether the absolute value of the difference between the voltage of the second bus after charging and the target voltage value is less than a preset error value. If so, the conversion module is activated to charge the first bus to a third preset value. Finally, it determines whether the absolute value of the difference between the sampling voltage of the first bus after charging and the third preset target charging value is less than a preset error value. If not, a pre-charge error is reported. If so, the first bus charges the second bus, charging the voltage of the second bus to the first preset value. The system checks whether the absolute value of the difference between the voltage sample value of the second bus and the first preset value is less than the preset error value. If yes, the resonant converter module is activated; otherwise, a pre-charge error is reported. It then checks whether the absolute value of the difference between the voltage of the first bus and the voltage of the second bus is less than the preset error value. If yes, the first bus supplies power to the inverter module, and the energy storage inverter system is activated; otherwise, a pre-charge error is reported. After reporting the pre-charge error, a 60-second wait is performed to check whether the absolute value of the difference between the voltage of the first bus and the voltage of the second bus is less than the preset error value. In practical applications, the waiting time can be set according to the actual situation; 60 seconds is only an example waiting time, and this application does not specify a specific waiting time. If yes, the first bus supplies power to the inverter module, and the energy storage inverter system operates normally; otherwise, the error is maintained, and maintenance is pending.

[0078] This embodiment provides a bus soft-start control method for an energy storage inverter system. The energy storage inverter system includes a first bus connected between a photovoltaic module and an inverter module, and a second bus connected between the energy storage module and the inverter module. A resonant converter module is connected between the energy storage module and the second bus. By pre-charging the second bus before the resonant converter module is turned on, the voltage of the second bus connected to the resonant converter module is increased. After the pre-charging of the second bus is completed, the resonant converter module is then turned on. This avoids the risk of excessive inrush current during capacitor charging of the second bus after the resonant converter module is turned on, which could damage the components of the energy storage inverter system.

[0079] Example 2

[0080] Figure 8 This is a schematic diagram of the bus soft-start control circuit of an energy storage inverter system as an example of this application; Figure 8 As shown, the control circuit includes: a first bus, a second bus, a resonant conversion module, and a conversion module;

[0081] One end of the first busbar is used to connect to the photovoltaic module, and the other end of the first busbar is used to connect to the inverter module; the inverter module is used to supply power to the energy storage inverter system.

[0082] One end of the second busbar is connected to one end of the resonant converter module, and the other end of the second busbar is used to connect to the inverter module; the other end of the resonant converter module is used to connect to the energy storage module.

[0083] The conversion module is connected between the first bus and the second bus. The conversion module is turned on before the resonant conversion module is turned on to precharge the second bus. The resonant conversion module is turned on after the second bus is precharged.

[0084] Specifically, refer to Figure 8 The control circuit of the energy storage inverter system includes a first bus, a second bus, a resonant converter module, and a conversion module. One end of the first bus is connected to the photovoltaic module, and the other end is connected to the inverter module. One end of the second bus is connected to one end of the resonant converter module, and the other end is connected to the inverter module. The other end of the resonant converter module is connected to the energy storage module. For example, the resonant converter module is a resonant DC-DC converter.

[0085] The conversion module is connected between the first bus and the second bus. The conversion module is activated before the resonant converter module is activated to pre-charge the second bus; exemplarily, the conversion module is a DC-DC converter. The resonant converter module is activated after the second bus pre-charging is complete. In this example, excessive voltage difference between the resonant converter module and the second bus is avoided, which could lead to excessive current and damage to the energy storage inverter system.

[0086] Reference Figure 8 The circuit also includes: a selection module; the selection module includes a first terminal a, a second terminal b, and a third terminal c;

[0087] The first terminal a is connected to the inverter module and the auxiliary power source, the second terminal b is connected to the other end of the first bus, and the third terminal c is connected to the other end of the second bus. The selection module is used to connect the first terminal to the second terminal after power-on when the voltage of the first bus is greater than the first preset value, so as to conduct the conductive path between the other end of the first bus and the inverter module and supply power to the inverter module.

[0088] Specifically, the control circuit further includes: a selection module; the selection module includes a first terminal a, a second terminal b, and a third terminal c; an exemplary selection module is a single-pole double-throw switch RY1; the first terminal a connects the inverter module and the auxiliary power source, wherein the auxiliary power source includes an AC power source and a battery (BAT) source. The second terminal b connects to the other end of the first bus, and the third terminal c connects to the other end of the second bus; the selection module is used to connect the first terminal to the second terminal after power-on, when the voltage of the first bus is greater than a first preset value, to conduct the conductive path between the other end of the first bus and the inverter module, thereby supplying power to the inverter module. For example, when the voltage of the first bus after power-on is greater than the first preset value, the first terminal a and the second terminal b of the selection module are connected. At this time, the conductive path between the first bus and the inverter module is completed, and the first bus supplies power to the inverter module, thereby improving the startup efficiency of the energy storage inverter system.

[0089] In this example, a selection module is configured to determine, based on the voltage value after the first bus is powered on, which terminal to connect to, in order to select whether the first bus or the auxiliary power source will serve as the second bus.

[0090] Optionally, a conversion module is provided to be activated after the first end of the selection module is connected to the second end, so as to perform voltage equalization on the first bus and the second bus and precharge the second bus.

[0091] Reference Figure 8 When the first terminal a of the selection module is connected to the second terminal b, the voltage of the first bus after power-on is greater than the first preset value. It is necessary to turn on the conversion module so that the voltage of the first bus and the second bus can be balanced through the turned-on conversion module, and the second bus can be pre-charged; thus avoiding damage to the energy storage inverter system due to excessive inrush current.

[0092] Optionally, the resonant conversion module is used to activate after the pre-charging of the second bus is completed.

[0093] Specifically, after the second busbar pre-charging is completed, and the voltages of the first and second buses are balanced, the resonant converter module is then turned on, thus avoiding the impact of excessive current on the resonant converter module.

[0094] Optionally, the circuit may also include: an auxiliary power source;

[0095] The selection module is also used to connect the first terminal to the third terminal when the voltage of the first bus is not greater than the first preset value, so as to precharge the second bus through the auxiliary power source.

[0096] Specifically, the control circuit of the energy storage inverter system also includes an auxiliary power source; the auxiliary power source includes an AC auxiliary power source and a BAT auxiliary power source, both of which can supply power to the grid and the inverter module. When the voltage on the first bus after power-on is not greater than a first preset value, the first terminal 'a' is connected to the third terminal 'c', connecting the auxiliary power source to the second bus to pre-charge the second bus. In this example, when the voltage on the first bus after power-on is not greater than the first preset value, the auxiliary power source is used to pre-charge the second bus, ensuring that the voltage difference between the second bus and the resonant converter module is not too large, thus protecting the energy storage inverter system from overcurrent damage.

[0097] Optionally, the conversion module is also used to turn on after the second bus has been pre-charged by the auxiliary power source, so as to perform voltage equalization of the first bus and the second bus through the conversion module.

[0098] Specifically, when the auxiliary power source needs to pre-charge the second bus, after the pre-charging is completed, the conversion module is activated to perform voltage balancing on the first and second buses. In this example, after pre-charging the second bus with the auxiliary power source, the conversion module is activated to perform voltage balancing on the first and second buses to ensure that the subsequent voltage difference between the first and second buses will not cause excessive current surges to the energy storage inverter system.

[0099] Optionally, the selection module includes a single-pole double-throw switch;

[0100] The common terminal of the single-pole double-throw switch is used as the first terminal to connect the auxiliary power source and the inverter module; the normally closed terminal of the single-pole double-throw switch is used as the second terminal to connect the other end of the first busbar; and the normally open terminal of the single-pole double-throw switch is used as the third terminal to connect the other end of the second busbar.

[0101] When the voltage of the first busbar is greater than the first preset value, the first terminal is connected to the second terminal; when the voltage of the first busbar is not greater than the first preset value, the first terminal is connected to the third terminal.

[0102] Specifically, the selected module is a single-pole double-throw (SPD) switch RY1. The common terminal of the SPD switch serves as the first terminal a, connecting the auxiliary power source and the inverter module. The normally closed terminal of the SPD switch serves as the second terminal b, connecting to the other end of the first busbar. The normally open terminal c of the SPD switch serves as the third terminal, connecting to the other end of the second busbar. When the voltage of the first busbar is greater than a first preset value, the first terminal a is connected to the second terminal b; when the voltage of the first busbar is not greater than the first preset value, the first terminal a is connected to the third terminal c. In this example, the connection state of the SPD switch is determined based on the voltage value of the first busbar, enabling the selection of different pre-charging methods for the second busbar, thus improving the startup efficiency of the energy storage inverter module.

[0103] Optional auxiliary power sources include AC power and batteries;

[0104] The AC power supply and battery are connected to the first terminal and the inverter module, respectively.

[0105] Specifically, the auxiliary power sources of the energy storage inverter system include an AC power auxiliary power source (AC auxiliary power source) and a battery auxiliary power source (BAT auxiliary power source); both the AC power source and the battery are connected to the first terminal a and the inverter module, respectively. For example, both the AC power source and the battery serve as auxiliary power sources to supply power to the inverter module; simultaneously, when the voltage of the first bus after power-on is not greater than a first preset value, the first terminal is connected to the third terminal c through the selection module to pre-charge the second bus.

[0106] Optionally, the circuit may also include: a first diode D2, a second diode D3, and a third diode D PV ;

[0107] The first diode D2 is disposed in the connection path between the AC power supply and the first terminal a. The positive terminal of the first diode D2 is connected to the AC power supply, and the negative terminal of the first diode D2 is connected to the first terminal a.

[0108] The second diode D3 is disposed in the connection path between the battery and the first terminal a. The positive terminal of the second diode D3 is connected to the battery, and the negative terminal of the second diode D3 is connected to the first terminal a.

[0109] Third diode D PV The positive terminal is connected to the photovoltaic module, and the third diode D PV The negative terminal is connected to one end of the first busbar.

[0110] Specifically, the circuit also includes a first diode D2, which is positioned in the connection path between the AC power supply and the first terminal a, with its anode connected to the AC power supply and its cathode connected to the first terminal a; a second diode D3 is positioned in the connection path between the battery and the first terminal a, with its anode connected to the battery and its cathode connected to the first terminal a; and a third diode D... PV The positive terminal is connected to the photovoltaic module, and the third diode D PV The negative terminal is connected to one end of the first busbar. The first diode, the second diode, and the third diode are all blocking diodes to ensure unidirectional current conduction.

[0111] Optionally, the circuit may also include: a fourth diode D1 and a first current limiting module;

[0112] The positive terminal of the fourth diode D1 is connected to the other end of the first busbar, and the negative terminal of the fourth diode D1 is connected to the first end of the first current limiting module.

[0113] The second end of the first current limiting module is connected to the second end b.

[0114] Specifically, the circuit also includes a fourth diode D1. The positive terminal of the fourth diode D1 is connected to the other end of the first busbar, and the negative terminal of the fourth diode D1 is connected to the first terminal of the first current limiting module. The second terminal of the second current limiting module is connected to the second terminal b of the selection module. The fourth diode also serves to ensure unidirectional current conduction. At the same time, the first current limiting module is used to limit excessive current and prevent overcurrent protection or damage to the energy storage inverter system.

[0115] Optionally, the circuit may also include: a second current limiting module;

[0116] The first end of the second current limiting module is connected to the third end c, and the second end of the second current limiting module is connected to the second bus.

[0117] Specifically, the circuit also includes a second current-limiting module; the first terminal of the second current-limiting module is connected to the third terminal c, and the second terminal of the second current-limiting module is connected to the second bus. Similarly, the second current-limiting module is used to limit excessive current and prevent overcurrent protection or damage to the energy storage inverter system.

[0118] Example 3

[0119] Figure 9 An exemplary schematic diagram of a bus soft-start control device for an energy storage inverter system is shown; the energy storage inverter system includes a first bus connected between a photovoltaic module and an inverter module, a second bus connected between an energy storage module and an inverter module, and a resonant converter module connected between the energy storage module and the second bus; the device includes:

[0120] The pre-charge module 21 is used to pre-charge the second bus before the resonant transformation module is turned on;

[0121] Module 22 is used to activate the resonant transformation module after the pre-charging of the second bus is completed.

[0122] Specifically, the complete architecture of an energy storage inverter system includes a photovoltaic module, an MPPT module, a first bus (equivalent to a large DC bus), an energy storage module, a second bus (equivalent to a small DC bus), a resonant converter module, a conversion module, and an inverter module. The first bus connects the photovoltaic module and the inverter module (including the inverter module in between), the second bus connects the energy storage module and the inverter module (including the inverter module in between), and the resonant converter module connects the energy storage module and the second bus. The inverter module supplies power to the energy storage inverter system itself. For example, during the initial startup of the energy storage inverter system, the photovoltaic module's light intensity is weak. When the energy storage module needs to be activated for charging and discharging, to avoid generating a large voltage when the resonant converter module connected to the energy storage module is activated, resulting in a large voltage difference between the second bus and the energy storage module, causing excessive inrush current and damage to components of the energy storage inverter system, such as switching transistors, the second bus is first pre-charged until its voltage reaches the target value. After the pre-charging of the second bus is completed, the resonant converter module is activated to start the energy storage module's charging and discharging. For example, the purpose of pre-charging is because there is a capacitor on the second bus. If the voltage difference is too large, directly turning on the resonant converter to charge the capacitor would result in an excessive inrush current, damaging the devices. The capacitance of the first bus is greater than that of the second bus. In this example, by pre-charging the second bus, the voltage difference between the resonant converter module and the second bus is reduced after the pre-charging is completed, thus avoiding the impact of excessive current on the energy storage inverter system and preventing damage to the various devices in the energy storage inverter system.

[0123] Optionally, the precharge module 21 is used for:

[0124] After power-on, obtain the voltage of the first bus;

[0125] When the voltage of the first bus is greater than the first preset value, the second bus is pre-charged based on the voltage of the first bus; the first preset value is obtained based on the voltage gain of the resonant converter module and the voltage of the energy storage module.

[0126] When the voltage of the first busbar is not greater than the first preset value, the second busbar is pre-charged based on the voltage provided by the auxiliary source.

[0127] Specifically, after the energy storage inverter system is powered on, the voltage of the first bus after power-on is acquired. When the voltage of the first bus is greater than a first preset value, the second bus is pre-charged based on the voltage of the first bus. The first preset value is obtained based on the voltage gain of the resonant converter module and the voltage of the energy storage power supply. For example, the voltage of the first bus after power-on is represented as V. BUS1 The first preset value is represented as M×V BAT M is the voltage gain of the resonant converter module, V BATThe voltage of the energy storage module is used. When the voltage of the first bus is not greater than a first preset value, the second bus is pre-charged based on the voltage provided by the auxiliary power source. In this example, by determining whether the voltage of the first bus is greater than the preset value, different pre-charging strategies are selected to pre-charge the second bus. This avoids the impact of excessive current on the energy storage inverter system while improving the startup efficiency of the energy storage inverter system.

[0128] Optionally, when the second bus is pre-charged based on the voltage provided by the auxiliary source, the activation module 22 is used to:

[0129] After the pre-charging of the second bus is completed, the conversion module is turned on to perform voltage balancing on the first and second buses;

[0130] After the equalization is completed, the resonance transformation module is activated.

[0131] Specifically, when the voltage of the first bus is not greater than a preset value after power-on, the voltage provided by the auxiliary power source is used to pre-charge the second bus. After the pre-charging of the second bus is completed, the conversion module is turned on to equalize the voltages of the first and second buses. After the voltage equalization of the first and second buses is completed, the resonant conversion module is turned on. This further avoids excessive current generation caused by an excessive voltage difference between the first and second buses after the conversion module is turned on, which could damage the components of the energy storage inverter system.

[0132] Optionally, the device further includes: an equalization module 23, which is used for:

[0133] Calculate the first absolute value of the difference between the voltage of the second bus after pre-charging and the target voltage of pre-charging; if the first absolute value is less than a preset error value, activate the conversion module so that the second bus charges the first bus through the conversion module until the voltage of the first bus reaches a second preset value; the second preset value is obtained based on the first preset value and a preset voltage margin.

[0134] Calculate the second absolute value of the difference between the voltage of the first bus after charging and the second preset value. If the second absolute value is less than the preset error value, the first bus charges the second bus through the conversion module until the voltage of the second bus reaches the first preset value.

[0135] Specifically, firstly, the first absolute value of the difference between the sampled voltage value of the second bus after pre-charging and the target pre-charging voltage value for the second bus is calculated; if the first absolute value is less than a preset error value, the conversion module is activated; for example, the target pre-charging voltage value for the second bus is max(V BUS1 ,U1), where V BUS1 U1 is the voltage of the first bus after power-on, U2 is the voltage provided by the auxiliary power source, and the sampling voltage at the end of the pre-charge of the second bus is represented as V.bus1 If ABS(V) bus1 -max(V BUS1 ,U1)) <V 误差 , where V 误差 If a preset error value is specified, the conversion module is activated, allowing the second bus to charge the first bus via the conversion module. This causes the first bus voltage to increase until it reaches a second preset value. The second preset value is derived from the first preset value and a preset voltage margin. For example, the second preset value is represented as M*V. BAT +V 裕量 , where V 裕量 This represents the preset voltage margin, where M is the voltage gain of the resonant converter module. In practical applications, the preset voltage margin is set based on empirical values, and is generally greater than the preset error value. After charging the voltage of the first bus to the second preset value, the second absolute value of the difference between the charged voltage of the first bus and the second preset value is calculated again. If the second absolute value is less than the preset error value, i.e., ABS(V) BUS2 -M*V BAT -V 裕量 ) <V 误差 V BUS2 This represents the sampled voltage value of the first bus after charging, with ABS indicating the calculation of the absolute value. Then, the first bus, through the conversion module, charges the second bus until its voltage reaches a first preset value. In practical applications, the voltage balancing process between the first and second buses is a pre-charging process of the first bus to the second bus. This completes the voltage balancing of the first and second buses, preventing excessive voltage difference between them, which could lead to excessive inrush current and damage to the energy storage inverter system.

[0136] Optionally, the device further includes: a computing module 24, which is used for:

[0137] After the equalization is completed, the third absolute value of the difference between the voltage of the first bus and the voltage of the second bus is calculated. If the third absolute value is less than the preset error value, the electrical connection between the first bus and the inverter module is turned on.

[0138] For example, after voltage balancing of the first bus and the second bus is completed, the third absolute value of the voltage difference between the first bus and the second bus after balancing is calculated. If the third absolute value is less than a preset error value, the electrical connection between the first bus and the inverter module is connected, and the first bus supplies power to the inverter module. For example, if ABS(V bus2 -V BUS3 ) <V 误差 Then the electrical connection between the first bus and the inverter module is established; where V bus2V represents the voltage of the second bus after the equalization process is completed. BUS3 This indicates the voltage of the third bus after voltage equalization is complete. When the absolute value of the voltage difference between the first bus and the second bus after voltage equalization is determined to be less than a preset threshold, the electrical connection between the first bus and the inverter module is activated. When the light intensity of the photovoltaic module connected to the first bus is sufficiently strong, the photovoltaic module is connected to the first bus to supply power to the inverter module, reducing the power loss of the energy storage module.

[0139] Optionally, the device further includes: an alarm module 25, which is used for:

[0140] If the first absolute value is not less than the preset error value, the second absolute value is not less than the preset error value, and the third absolute value is not less than the preset error value, a pre-charge error is reported.

[0141] Specifically, if the first absolute value, the second absolute value, and the third absolute value obtained from the aforementioned calculations are not less than the preset error value, a pre-charge error must be reported before proceeding to the next step. If the preset error value is not met, a pre-charge error is reported, and no operation is performed, awaiting maintenance; this further protects the energy storage inverter system and enhances its safety.

[0142] Optionally, the device further includes: a determining module 26, which is used for:

[0143] When the second bus is pre-charged based on the voltage of the first bus, the pre-charging of the second bus is determined to be completed when the voltage of the second bus reaches the first preset value.

[0144] When the second bus is pre-charged based on the voltage provided by the auxiliary source, the pre-charging of the second bus is determined to be completed when the voltage of the second bus reaches a third preset value; the third preset value is obtained based on the voltage of the auxiliary source and the voltage of the first bus after it is powered on.

[0145] Specifically, when the second bus is pre-charged based on the voltage of the first bus, the pre-charging of the second bus is considered complete when the voltage of the second bus reaches the aforementioned first preset value. When the second bus is pre-charged based on the voltage provided by the auxiliary power source, the pre-charging of the second bus is determined to be complete when the voltage of the second bus reaches the third preset value. The third preset value is obtained based on the voltage of the auxiliary power source and the voltage of the first bus after power-on, and is the aforementioned pre-charging target voltage value of the second bus, max(V). BUS1 U1).

[0146] This embodiment provides a bus soft-start control device for an energy storage inverter system. The energy storage inverter system includes a first bus connected between the photovoltaic module and the inverter module, and a second bus connected between the energy storage module and the inverter module. A resonant converter module is connected between the energy storage module and the second bus. By pre-charging the second bus before the resonant converter module is turned on, the voltage of the second bus connected to the resonant converter module is increased. After the pre-charging of the second bus is completed, the resonant converter module is then turned on. This avoids the risk of damage to the components of the energy storage inverter system caused by excessive inrush current when the capacitor of the second bus is charged after the resonant converter module is turned on.

[0147] Example 4

[0148] Figure 10 The diagram above illustrates the structure of an electronic device, which includes:

[0149] The device includes a processor 291 and a memory 292; it may also include a communication interface 293 and a bus 294. The processor 291, memory 292, and communication interface 293 can communicate with each other via the bus 294. The communication interface 293 can be used for information transmission. The processor 291 can invoke logical instructions stored in the memory 292 to execute the methods described in the example above.

[0150] Furthermore, the logic instructions in the aforementioned memory 292 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium.

[0151] The memory 292, as a computer-readable storage medium, can be used to store software programs and computer-executable programs, such as program instructions / modules corresponding to the methods in the embodiments of this application. The processor 291 executes functional applications and data processing by running the software programs, instructions, and modules stored in the memory 292, that is, it implements the methods in the above method examples.

[0152] The memory 292 may include a program storage area and a data storage area. 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 terminal device. Furthermore, the memory 292 may include high-speed random access memory and may also include non-volatile memory.

[0153] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the method in any of the embodiments.

[0154] This application also provides a computer program product, including a computer program that, when executed by a processor, is used to implement the method in any of the embodiments.

[0155] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily essential to this application.

[0156] It should be further noted that although the steps in the flowchart are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowchart may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the sub-steps or stages of other steps.

[0157] It should be understood that the above-described device embodiments are merely illustrative, and the device of this application can also be implemented in other ways. For example, the division of units / modules in the above embodiments is only a logical functional division, and there may be other division methods in actual implementation. For example, multiple units, modules, or components may be combined, or integrated into another system, or some features may be ignored or not executed.

[0158] Furthermore, unless otherwise specified, the functional units / modules in the various embodiments of this application can be integrated into one unit / module, or each unit / module can exist physically separately, or two or more units / modules can be integrated together. The integrated units / modules described above can be implemented in hardware or as software program modules.

[0159] When integrated units / modules are implemented in hardware, the hardware can be digital circuits, analog circuits, etc. The physical implementation of the hardware structure includes, but is not limited to, transistors, memristors, etc. Unless otherwise specified, the processor can be any suitable hardware processor, such as a CPU, GPU, FPGA, DSP, and ASIC, etc. Unless otherwise specified, the storage unit can be any suitable magnetic or magneto-optical storage medium, such as Resistive Random Access Memory (RRAM), Dynamic Random Access Memory (DRAM), Static Random Access Memory (SRAM), Enhanced Dynamic Random Access Memory (EDRAM), High-Bandwidth Memory (HBM), Hybrid Memory Cube (HMC), etc.

[0160] If the integrated unit / module is implemented as a software program module and sold or used as an independent product, it can be stored in a computer-readable storage device (CMD). Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a memory 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 of the various embodiments of this application. The aforementioned memory includes various media capable of storing program code, such as a USB flash drive, read-only memory (ROM), random access memory (RAM), portable hard drive, magnetic disk, or optical disk.

[0161] In the above embodiments, the descriptions of each embodiment have their own emphasis. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments. The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0162] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0163] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A bus soft-start control method for an energy storage inverter system, characterized in that, The energy storage inverter system includes a first busbar connected between a photovoltaic module and an inverter module, and a second busbar connected between an energy storage module and an inverter module, wherein a resonant converter module is connected between the energy storage module and the second busbar; the method includes: Before the resonant transformation module is turned on, the second bus is pre-charged; After the pre-charging of the second bus is completed, the resonant conversion module is turned on.

2. The method according to claim 1, characterized in that, The pre-charging of the second bus before the resonant conversion module is turned on includes: After power-on, obtain the voltage of the first bus; When the voltage of the first bus is greater than a first preset value, the second bus is pre-charged based on the voltage of the first bus; the first preset value is obtained based on the voltage gain of the resonant converter module and the voltage of the energy storage module. When the voltage of the first busbar is not greater than the first preset value, the second busbar is pre-charged based on the voltage provided by the auxiliary source.

3. The method according to claim 2, characterized in that, When the second bus is pre-charged based on the voltage provided by the auxiliary source, the step of activating the resonant conversion module after the pre-charging of the second bus is completed specifically includes: After the pre-charging of the second bus is completed, the conversion module is turned on to perform voltage balancing on the first bus and the second bus; After the equalization is completed, the resonant transformation module is activated.

4. The method according to claim 3, characterized in that, The activation conversion module, for voltage balancing of the first bus and the second bus, includes: Calculate the first absolute value of the difference between the voltage of the second bus after pre-charging and the target voltage of pre-charging; if the first absolute value is less than a preset error value, then activate the conversion module so that the second bus charges the first bus through the conversion module until the voltage of the first bus reaches a second preset value; the second preset value is obtained based on the first preset value and a preset voltage margin. Calculate the second absolute value of the difference between the voltage of the first bus after charging and the second preset value. If the second absolute value is less than the preset error value, the first bus charges the second bus through the conversion module until the voltage of the second bus reaches the first preset value.

5. The method according to claim 4, characterized in that, After the equalization process is completed and the resonant transformation module is activated, the process further includes: After the equalization is completed, the third absolute value of the difference between the voltage of the first bus and the voltage of the second bus is calculated. If the third absolute value is less than the preset error value, the electrical connection between the first bus and the inverter module is turned on.

6. The method according to claim 5, characterized in that, The method further includes: If the first absolute value is not less than the preset error value, the second absolute value is not less than the preset error value, and the third absolute value is not less than the preset error value, a pre-charge error is reported.

7. The method according to any one of claims 2-6, characterized in that, The method further includes: When the second bus is pre-charged based on the voltage of the first bus, the pre-charging of the second bus is determined to be completed when the voltage of the second bus reaches the first preset value. When the second bus is pre-charged based on the voltage provided by the auxiliary source, the pre-charging of the second bus is determined to be completed when the voltage of the second bus reaches a third preset value; the third preset value is obtained based on the voltage of the auxiliary source and the voltage of the first bus after it is powered on.

8. A bus soft-start control circuit for an energy storage inverter system, characterized in that, include: First busbar, second busbar, resonant transformation module, and conversion module; One end of the first busbar is used to connect to the photovoltaic module, and the other end of the first busbar is used to connect to the inverter module; One end of the second busbar is connected to one end of the resonant converter module, and the other end of the second busbar is used to connect to the inverter module; the other end of the resonant converter module is used to connect to the energy storage module. The conversion module is connected between the first bus and the second bus. The conversion module is turned on before the resonant conversion module is turned on to precharge the second bus. The resonant conversion module is turned on after the precharging of the second bus is completed.

9. The circuit according to claim 8, characterized in that, The circuit further includes a selection module; the selection module includes a first terminal, a second terminal, and a third terminal. The first end is connected to the inverter module and the auxiliary power source, the second end is connected to the other end of the first bus, and the third end is connected to the other end of the second bus. The selection module is used to connect the first end to the second end after power-on when the voltage of the first bus is greater than a first preset value, so as to conduct the conductive path between the other end of the first bus and the inverter module and supply power to the inverter module.

10. The circuit according to claim 9, characterized in that, The conversion module is used to activate after the first end of the selection module is connected to the second end, so as to perform voltage balancing on the first bus and the second bus and pre-charge the second bus.

11. The circuit according to claim 10, characterized in that, The resonant transformation module is used to be turned on after the pre-charging of the second bus is completed.

12. The circuit according to claim 9, characterized in that, The selection module includes a single-pole double-throw switch; The common terminal of the single-pole double-throw switch is used as the first terminal to connect the auxiliary power source and the inverter module; the normally closed terminal of the single-pole double-throw switch is used as the second terminal to connect the other end of the first busbar; and the normally open terminal of the single-pole double-throw switch is used as the third terminal to connect the other end of the second busbar. When the voltage of the first busbar is greater than the first preset value, the first end is connected to the second end; when the voltage of the first busbar is not greater than the first preset value, the first end is connected to the third end.

13. The circuit according to claim 12, characterized in that, The auxiliary power source includes an AC power supply and a battery; the circuit also includes: a first diode, a second diode, and a third diode; The first diode is disposed in the connection path between the AC power supply and the first terminal, with the anode of the first diode connected to the AC power supply and the cathode of the first diode connected to the first terminal. The second diode is disposed in the connection path between the battery and the first terminal, with the positive terminal of the second diode connected to the battery and the negative terminal of the second diode connected to the first terminal; The positive terminal of the third diode is connected to the photovoltaic module, and the negative terminal of the third diode is connected to one end of the first busbar.

14. The circuit according to claim 9, characterized in that, The circuit also includes: a fourth diode and a first current limiting module; The positive terminal of the fourth diode is connected to the other end of the first busbar, and the negative terminal of the fourth diode is connected to the first end of the first current limiting module. The second end of the first current limiting module is connected to the second end.

15. The circuit according to any one of claims 9-14, characterized in that, The circuit also includes: a second current limiting module; The first end of the second current limiting module is connected to the third end, and the second end of the second current limiting module is connected to the second bus.

16. A bus soft-start control device for an energy storage inverter system, characterized in that, The energy storage inverter system includes a first busbar connected between a photovoltaic module and an inverter module, and a second busbar connected between the energy storage module and the inverter module. A resonant converter module is connected between the energy storage module and the second busbar. The pre-charge module is used to pre-charge the second bus before the resonant transformation module is turned on; the turn-on module is used to turn on the resonant transformation module after the pre-charging of the second bus is completed.

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