Control method and device of inverter system and inverter system

Abstract

The present application discloses a control method, device and inverter system of an inverter system, which belongs to the field of inverters. The control method of the inverter system includes: obtaining target electrical parameters corresponding to target objects in capacitors and neutral lines, the target electrical parameters including at least one of the capacitor ripple voltage, the load information corresponding to each phase line of the inverter system and the detection signal of the neutral line; based on the target threshold and the target electrical parameters, executing the control logic corresponding to the target electrical parameters to reduce the target electrical parameters. The control method of the inverter system of the present application can effectively control the target electrical parameters within a reasonable range, reduce the shutdown frequency of the inverter system, ensure the normal operation of the inverter system, extend the service life of the inverter system, and improve the user experience by executing the control logic corresponding to the target electrical parameters to reduce the target electrical parameters when the target electrical parameters corresponding to the capacitor or the neutral line are abnormal.

Description

Technical Field

[0001] The present application belongs to the field of inverters, and in particular, relates to a control method and device for an inverter system, and an inverter system. Background Art

[0002] For multi-level inverter circuits, multiple bus capacitors are connected in series between the positive and negative busbars. In the related art, during the operation of the inverter circuit, the capacitors in the inverter circuit lack effective self-protection methods. Affected by factors such as load changes, it is easy to cause the ripple voltage of the bus capacitor to exceed the specification requirements, causing the capacitor life to decay or fail; and cause the detection signal value to increase abnormally, causing risks such as overcurrent and overheating, thereby affecting the service life of the inverter circuit. Summary of the invention

[0003] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a control method, device and inverter system of an inverter system, which can effectively control the target electrical parameters within a reasonable range, thereby reducing the shutdown frequency of the inverter system, ensuring the normal operation of the inverter system, extending the service life of the inverter system, and improving the user experience.

[0004] In a first aspect, the present application provides a control method for an inverter system, wherein the inverter system comprises a plurality of capacitors connected in series, wherein the plurality of capacitors connected in series are connected between a positive bus and a negative bus, and a neutral point between the plurality of capacitors connected in series is connected to a neutral line of the inverter system; the method comprises:

[0005] Acquire target electrical parameters corresponding to the target objects in the capacitor and the neutral line, wherein the target electrical parameters include at least one of the capacitor ripple voltage of the capacitor, the load information corresponding to each phase line of the inverter system, and a detection signal of the neutral line; the detection signal is a signal for characterizing the magnitude of the neutral line current of the neutral line;

[0006] Based on the target threshold and the target electrical parameter, a control logic corresponding to the target electrical parameter is executed to reduce the target electrical parameter.

[0007] According to the control method of the inverter system of the present application, by executing the control logic corresponding to the target electrical parameters to reduce the target electrical parameters when the target electrical parameters corresponding to the capacitor or the neutral line are abnormal, the target electrical parameters can be effectively controlled within a reasonable range, thereby reducing the shutdown frequency of the inverter system, ensuring the normal operation of the inverter system, extending the service life of the inverter system, improving the user experience, and being suitable for a wide range of inverter scenarios.

[0008] According to an embodiment of the present application, when the target electrical parameter includes at least one of the capacitor ripple voltage and load information corresponding to each phase line of the inverter system, the target threshold includes a first threshold; and based on the target threshold and the target electrical parameter, executing a control logic corresponding to the target electrical parameter to reduce the target electrical parameter includes:

[0009] When the capacitor ripple voltage exceeds the first threshold and / or when it is determined based on the load information that the loads of the phases are unbalanced, the bus voltage of the inverter system is increased to reduce the target electrical parameter.

[0010] According to one embodiment of the present application, the step of increasing the bus voltage of the inverter system to reduce the target electrical parameter includes:

[0011] Increasing the bus voltage of the inverter system until the newly acquired capacitor ripple voltage does not exceed the first threshold;

[0012] or,

[0013] Based on a first correlation between the change in the capacitor ripple voltage and the bus voltage, determining to reduce the capacitor ripple voltage to a first target value of the bus voltage corresponding to the first threshold; the first correlation is predetermined;

[0014] increasing the bus voltage to the first target value;

[0015] or,

[0016] Determining a first PI control target based on an operating parameter of the inverter system and a reference value of a capacitor ripple voltage;

[0017] Based on the first PI control target, increasing the bus voltage of the inverter system;

[0018] or,

[0019] In a case where the capacitor ripple voltage is greater than a reference value of the capacitor ripple voltage, increasing the bus voltage of the inverter system based on a first rate;

[0020] When the capacitor ripple voltage is not greater than a reference value of the capacitor ripple voltage, the bus voltage of the inverter system is reduced based on a second rate.

[0021] According to one embodiment of the present application, the step of increasing the bus voltage of the inverter system to reduce the target electrical parameter includes:

[0022] Without triggering bus voltage derating and / or overvoltage protection of the inverter system, the bus voltage of the inverter system is increased to reduce the target electrical parameter.

[0023] According to an embodiment of the present application, the capacitor ripple voltage is obtained based on the following steps:

[0024] Obtaining the actual ripple voltage of each capacitor within a target period;

[0025] A maximum value among the multiple actual ripple voltages, or an average value corresponding to the multiple actual ripple voltages, is determined as the capacitor ripple voltage.

[0026] According to an embodiment of the present application, when the target electrical parameter includes the capacitor ripple voltage, the target threshold includes a second threshold; and based on the target threshold and the target electrical parameter, executing a control logic corresponding to the target electrical parameter to reduce the target electrical parameter includes:

[0027] When the capacitor ripple voltage exceeds the second threshold, an output electrical signal of the inverter system is reduced, where the output electrical signal includes an output current or an output power.

[0028] According to one embodiment of the present application, reducing the output electrical signal of the inverter system includes:

[0029] reducing the output electrical signal of the inverter system until the newly acquired capacitor corresponding to the capacitor ripple voltage does not exceed the second threshold;

[0030] or,

[0031] Based on a second correlation relationship between the change in the capacitor ripple voltage and the output electrical signal of the inverter system, determining to reduce the capacitor ripple voltage to a second target value of the output electrical signal corresponding to the second threshold; the second correlation relationship is predetermined;

[0032] reducing the output electrical signal to the second target value;

[0033] or,

[0034] Determining a second PI control target based on an operating parameter of the inverter system and a reference value of a capacitor ripple voltage;

[0035] Based on the second PI control target, reducing the output electrical signal of the inverter system;

[0036] or,

[0037] When the capacitor ripple voltage is greater than a reference value of the capacitor ripple voltage, reducing the output electrical signal of the inverter system based on a third rate;

[0038] In a case where the capacitor ripple voltage is not greater than a reference value of the capacitor ripple voltage, the output electrical signal of the inverter system is increased based on a fourth rate.

[0039] According to an embodiment of the present application, when the target electrical parameter includes the capacitor ripple voltage, the target threshold includes a third threshold; and based on the target threshold and the target electrical parameter, executing a control logic corresponding to the target electrical parameter to reduce the target electrical parameter includes:

[0040] When the capacitor ripple voltage exceeds the third threshold, the inverter system is controlled to shut down; the third threshold is greater than the first threshold and the third threshold is greater than the second threshold.

[0041] According to an embodiment of the present application, the target threshold is dynamically adjusted based on at least one of a temperature of the inverter system and a temperature of a neutral terminal.

[0042] According to one embodiment of the present application, the target threshold is dynamically adjusted based on at least one of the temperature of the inverter system and the temperature of the neutral terminal, including:

[0043] When the temperature is greater than a first temperature threshold, reducing the target threshold;

[0044] When the temperature is less than a second temperature threshold, the target threshold is increased; wherein the second temperature threshold is less than the first temperature threshold.

[0045] According to an embodiment of the present application, when the target electrical parameter includes the detection signal of the neutral line, the target threshold includes a fourth threshold; and based on the target threshold and the target electrical parameter, executing a control logic corresponding to the target electrical parameter to reduce the target electrical parameter includes:

[0046] When the detection signal exceeds the fourth threshold, the output electrical signal of the inverter system is reduced to reduce the detection signal, where the output electrical signal includes an output current or an output power.

[0047] According to an embodiment of the present application, when the target electrical parameter includes the detection signal of the neutral line, the target threshold includes a fifth threshold; and based on the target threshold and the target electrical parameter, executing a control logic corresponding to the target electrical parameter to reduce the target electrical parameter includes:

[0048] When the detection signal exceeds the fifth threshold, the inverter system is controlled to shut down; the fifth threshold is greater than the fourth threshold

[0049] In a second aspect, the present application provides a control device for an inverter system, wherein the inverter system includes a plurality of capacitors connected in series, wherein the plurality of capacitors connected in series are connected between positive and negative busbars, and a neutral point between the plurality of capacitors connected in series is connected to a neutral line of the inverter system; the device includes:

[0050] A first processing module is used to obtain target electrical parameters corresponding to the target object in the capacitor and the neutral line, wherein the target electrical parameters include at least one of the capacitor ripple voltage of the capacitor, the load information corresponding to each phase line of the inverter system, and the detection signal of the neutral line; the detection signal is a signal for characterizing the magnitude of the neutral line current of the neutral line;

[0051] The second processing module is used to execute a control logic corresponding to the target electrical parameter based on the target threshold and the target electrical parameter to reduce the target electrical parameter.

[0052] According to the control device of the inverter system of the present application, by executing the control logic corresponding to the target electrical parameters to reduce the target electrical parameters when the target electrical parameters corresponding to the capacitor or the neutral line are abnormal, the target electrical parameters can be effectively controlled within a reasonable range, thereby reducing the shutdown frequency of the inverter system, ensuring the normal operation of the inverter system, extending the service life of the inverter system, improving the user experience, and being suitable for a wide range of inverter scenarios.

[0053] In a third aspect, the present application provides an inverter system based on the control method of the inverter system according to the first aspect, comprising:

[0054] An inverter circuit, wherein the inverter circuit is connected to a DC voltage via positive and negative bus bars;

[0055] A plurality of capacitors connected in series, wherein the plurality of capacitors connected in series are connected between the positive and negative busbars, and a neutral point between the plurality of capacitors connected in series is connected to a neutral line of the inverter system;

[0056] At least one phase line, the output end of the inverter circuit is connected to the at least one phase line.

[0057] In a fourth aspect, the present application provides a non-transitory computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the control method of the inverter system as described in the first aspect above.

[0058] In a fifth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the control method of the inverter system as described in the first aspect above.

[0059] The above one or more technical solutions in the embodiments of the present application have at least one of the following technical effects:

[0060] By executing the control logic corresponding to the target electrical parameters to reduce the target electrical parameters when the target electrical parameters corresponding to the capacitor or the neutral line are abnormal, the target electrical parameters can be effectively controlled within a reasonable range, thereby reducing the shutdown frequency of the inverter system, ensuring the normal operation of the inverter system, extending the service life of the inverter system, and improving the user experience. It is suitable for a wide range of inverter scenarios.

[0061] Furthermore, by controlling the inverter system to shut down when the capacitor ripple voltage exceeds the third threshold, it is possible to add a bottom-line protection measure to shut down the inverter system for protection when other adjustment measures fail due to inverter abnormality, thereby reducing the safety risks caused by abnormal operation and extending the service life of the inverter system.

[0062] Furthermore, by dynamically adjusting the target threshold based on the temperature of the inverter system and / or the temperature of the neutral terminal, adaptive adjustment of the threshold can be achieved, thereby improving the precision, accuracy and flexibility of the inverter system control.

[0063] Furthermore, by determining the maximum value of multiple actual ripple voltages, or the average value corresponding to multiple actual ripple voltages as the capacitor ripple voltage as a subsequent inverter system control indicator, it has better representativeness, can improve the precision and accuracy of control, greatly reduce the frequency of inverter system shutdown due to faults, extend the service life of the inverter system, and improve user experience.

[0064] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0066] Figure 1 is a flow chart of a control method of an inverter system provided in an embodiment of the present application;

[0067] Figure 2 It is one of the principle schematic diagrams of the control method of the inverter system provided in the embodiment of the present application;

[0068] Figure 3 This is the second principle schematic diagram of the control method of the inverter system provided in the embodiment of the present application;

[0069] Figure 4 This is the third principle schematic diagram of the control method of the inverter system provided in the embodiment of the present application;

[0070] Figure 5 This is the fourth principle schematic diagram of the control method of the inverter system provided in the embodiment of the present application;

[0071] Figure 6 is a structural schematic diagram of a control device of an inverter system provided in an embodiment of the present application;

[0072] Figure 7 It is one of the structural schematic diagrams of the inverter system provided in the embodiment of the present application;

[0073] Figure 8 This is the second structural schematic diagram of the inverter system provided in the embodiment of the present application;

[0074] Fig. 9 This is the third structural schematic diagram of the inverter system provided in the embodiment of the present application;

[0075] Fig.10 is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application;

[0076] Fig.11 This is the fifth principle schematic diagram of the control method of the inverter system provided in the embodiment of the present application;

[0077] Fig.12 This is the fourth structural diagram of the inverter system provided in the embodiment of the present application;

[0078] Fig.13 This is the fifth structural diagram of the inverter system provided in the embodiment of the present application;

[0079] Fig.14 This is the sixth structural diagram of the inverter system provided in the embodiment of the present application. DETAILED DESCRIPTION

[0080] The following will be combined with the drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of this application.

[0081] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0082] In the following, in combination with the accompanying drawings, the control method of the inverter system, the control device of the inverter system, the electronic device and the readable storage medium provided in the embodiments of the present application are described in detail through specific embodiments and their application scenarios.

[0083] The control method of the inverter system may be applied to a terminal, and may be specifically executed by hardware or software in the terminal.

[0084] The control method of the inverter system provided in the embodiment of the present application, the execution subject of the control method of the inverter system may be an electronic device or a functional module or functional entity in the electronic device that can implement the control method of the inverter system. The electronic devices mentioned in the embodiment of the present application include but are not limited to mobile phones, tablet computers, computers, cameras and wearable devices, etc. The control method of the inverter system provided in the embodiment of the present application is described below by taking the electronic device as the execution subject as an example.

[0085] like Figure 1 As shown, the control method of the inverter system includes: step 110 and step 120.

[0086] like Figure 7 As shown, the inverter system includes a plurality of capacitors (bus capacitors) connected in series, and the plurality of capacitors connected in series are connected between the positive and negative bus bars.

[0087] The neutral point between the plurality of capacitors connected in series is connected to the neutral line of the inverter system.

[0088] The number of capacitors may be 2, 4, 6 or other numbers.

[0089] Figure 8 An example of a circuit structure with two capacitors connected in series is shown. Fig. 9 An example circuit structure of four capacitors connected in series is shown.

[0090] The inverter system may be a single-phase inverter system or a multi-phase inverter system.

[0091] The control method of the inverter system can be applied to multi-level inverters, including but not limited to: three-level inverters, five-level inverters and other multi-level inverters, wherein the two-phase bridge arm inverter of the three-level inverter is as follows: Fig.13 and Fig.14 As shown, the schematic diagram of the single-phase bridge arm of the five-level inverter is as follows Fig. 9 shown.

[0092] Step 110: acquiring target electrical parameters corresponding to target objects in the capacitor and the neutral line, wherein the target electrical parameters include at least one of a capacitor ripple voltage of the capacitor, load information corresponding to each phase line of the inverter system, and a detection signal of the neutral line;

[0093] In this step, the target object may be any one of a capacitor and a neutral line.

[0094] When the target object is a capacitor, the target electrical parameter includes at least one of a capacitor ripple voltage of the capacitor and load information corresponding to each phase line of the inverter system.

[0095] In the actual implementation process, each capacitor corresponds to an actual ripple voltage in each cycle.

[0096] The actual ripple voltage is the difference between the maximum voltage and the minimum voltage of the bus capacitor in the same cycle.

[0097] In a three-level inverter, the actual ripple voltage is half the bus ripple voltage.

[0098] The capacitor ripple voltage is a representative value of an actual ripple voltage corresponding to a capacitor included in the inverter system within any target period.

[0099] For example, the actual ripple voltage of any capacitor among the multiple capacitors within the target period may be used as the capacitor ripple voltage of the inverter system within the target period.

[0100] In some embodiments, the capacitor ripple voltage may be obtained based on the following steps:

[0101] Obtain the actual ripple voltage of each capacitor in the target cycle;

[0102] A maximum value among the multiple actual ripple voltages, or an average value corresponding to the multiple actual ripple voltages, is determined as the capacitor ripple voltage.

[0103] In this embodiment, for an inverter system including multiple bus capacitors, the actual ripple voltage of each capacitor in the same cycle can be obtained respectively, and then the maximum value is screened from the multiple actual ripple voltages, and the maximum value is determined as the capacitor ripple voltage of the inverter system in the cycle.

[0104] Alternatively, an average value may be calculated for a plurality of actual ripple voltages, and the calculated average value may be determined as the capacitor ripple voltage of the inverter system in the period.

[0105] According to the control method of the inverter system provided in the embodiment of the present application, by determining the maximum value of multiple actual ripple voltages, or the average value corresponding to multiple actual ripple voltages as the capacitor ripple voltage as a subsequent inverter system control indicator, it has better representativeness, can improve the precision and accuracy of control, greatly reduce the frequency of shutdown of the inverter system due to faults, extend the service life of the inverter system, and improve user experience.

[0106] The load information may include, but is not limited to: the corresponding power and current of each phase of the inverter system.

[0107] The load information is used to determine whether the phases of the inverter system are balanced.

[0108] like Figure 2 The following is a schematic diagram of capacitor ripple voltage when the output of a three-phase inverter system is unbalanced.

[0109] When the target object is the center line, the target electrical parameter includes: a detection signal.

[0110] The detection signal is a signal used to characterize the magnitude of the neutral line current of the neutral line.

[0111] In some embodiments, the detection signal may include: neutral current or temperature information associated with the neutral current.

[0112] The temperature information associated with the neutral current is used to reflect the magnitude of the neutral current.

[0113] The temperature information associated with the neutral current may include: the temperature of the neutral terminal or the temperature of the balancing bridge, etc.

[0114] The temperature information associated with the neutral current is consistent with the change trend of the neutral current; for example, the larger the neutral current is, the higher the temperature associated with it is; and the smaller the neutral current is, the lower the temperature associated with it is.

[0115] The neutral current may be directly collected by arranging sensors, or may be indirectly calculated through phase currents, which is not limited in the present application.

[0116] Temperature information associated with the neutral current can be acquired through sensors.

[0117] Step 120 : Based on the target threshold and the target electrical parameter, execute a control logic corresponding to the target electrical parameter to reduce the target electrical parameter.

[0118] In this step, the target threshold is a trigger value used to determine whether measures need to be taken to reduce the target electrical parameter.

[0119] The target threshold may include one or more thresholds, and the specific value of the target threshold may be customized based on the user.

[0120] In some embodiments, the target threshold may include at least one of a first threshold, a second threshold, a third threshold, a fourth threshold, and a fifth threshold.

[0121] Different thresholds are used to execute different control logics.

[0122] In the actual execution process, a corresponding relationship may be established in advance between each threshold and the control logic corresponding to the threshold.

[0123] The value of each threshold can be customized by the user.

[0124] Among them, the first threshold should be smaller than the third threshold; the second threshold should be smaller than the third threshold.

[0125] The fourth threshold should be smaller than the fifth threshold.

[0126] In some embodiments, the target threshold may be dynamically adjusted based on at least one of a temperature of the inverter system and a temperature of the neutral terminal.

[0127] In this embodiment, the temperature of the inverter system can be obtained by performing arithmetic operations on the temperatures of each device or some of the devices in the inverter system; for example, the maximum value of the temperatures of each device can be used as the temperature of the inverter system, or the average value of the temperatures of all or some of the devices can be taken as the temperature of the inverter system, etc.

[0128] The temperature of the neutral terminal is the temperature at the neutral output terminal of the inverter system. The temperature of the neutral terminal may be a temperature used to reflect the neutral current.

[0129] The target threshold value can be adaptively adjusted based on the temperature of the inverter system or the temperature of the neutral terminal. However, during the adjustment process, the relative size relationship between the corresponding threshold values ​​should be kept unchanged.

[0130] According to the control method of the inverter system provided in the embodiment of the present application, the size of the target threshold is dynamically adjusted based on the temperature of the inverter system and / or the temperature of the neutral terminal, which can achieve adaptive adjustment of the threshold, thereby improving the precision, accuracy and flexibility of the inverter system control.

[0131] In some embodiments, the target threshold is dynamically adjusted based on at least one of the temperature of the inverter system and the temperature of the neutral terminal, which may include:

[0132] When the temperature is greater than a first temperature threshold, reducing the target threshold;

[0133] When the temperature is less than a second temperature threshold, the target threshold is increased; wherein the second temperature threshold is less than the first temperature threshold.

[0134] In this embodiment, the first temperature threshold is a larger temperature threshold, and the second temperature threshold is a lower temperature threshold.

[0135] The first temperature threshold and the second temperature threshold may be user-defined.

[0136] For example, when it is judged that the temperature of the inverter system is high (such as greater than the first temperature threshold), the first threshold, the second threshold and the third threshold are reduced; when it is judged that the temperature of the inverter system is low (such as less than the second temperature threshold), the first threshold, the second threshold and the third threshold are increased.

[0137] When the temperature of the neutral terminal is high, the fourth threshold and / or the fifth threshold are lowered; when the temperature of the neutral terminal is low, the fourth threshold and / or the fifth threshold are increased.

[0138] However, it should be noted that no matter how the first threshold, the second threshold and the third threshold are adjusted, the first threshold must be less than the third threshold, and the second threshold must be less than the third threshold; and the fifth threshold must be kept greater than the fourth threshold.

[0139] By comparing the target electrical parameter with the target threshold, it can be determined whether the current operating condition data of the target object corresponding to the target electrical parameter is likely to exceed the specification.

[0140] In some embodiments, for example, when the inverter system is a multi-phase inverter system, it is also possible to determine whether the current operating condition data of the target object corresponding to the target electrical parameter is likely to exceed the specification based on the load information.

[0141] When it is determined that the current operating condition data of the target object may exceed the specifications, based on the target object, the control logic corresponding to the target object is determined, and the inverter system is adjusted based on the control logic to reduce the target electrical parameters corresponding to the target object, thereby minimizing the possibility of the operating condition data of the target object exceeding the specifications.

[0142] It can be understood that, when the target object is a capacitor, reducing the target electrical parameter may be manifested as reducing the capacitor ripple voltage of the capacitor.

[0143] In the actual implementation process, the capacitor ripple voltage of the capacitor can be reduced by adjusting the bus voltage, triggering inverter derating, or controlling the inverter system to shut down.

[0144] In the case where the target object is the neutral line, a reduction in the target electrical parameter may manifest as a reduction in the detection signal.

[0145] In actual implementation, the detection signal can be reduced by triggering inverter derating or controlling the inverter system to shut down.

[0146] During the research and development process, the inventors discovered that in the related technologies, the control of capacitor ripple voltage or neutral current is usually carried out by performing a fault shutdown after identifying that the capacitor ripple voltage exceeds the specification; however, this method will directly cause the inverter to shut down, affecting the user experience.

[0147] In the present application, by real-time detection of the target electrical parameters corresponding to the capacitor or the neutral line, and executing the control logic corresponding to the target electrical parameters to reduce the target electrical parameters when the target parameters are abnormal, the target electrical parameters can be effectively controlled within a reasonable range, reducing the shutdown frequency caused by abnormalities, thereby reducing the shutdown frequency of the inverter system; in addition, by controlling the target parameters within a reasonable range, the failure risk of capacitors, etc. can also be reduced, ensuring the normal operation of the inverter system, extending the service life of the inverter system, and improving the user experience.

[0148] According to the control method of the inverter system provided in the embodiment of the present application, by executing the control logic corresponding to the target electrical parameters to reduce the target electrical parameters when the target electrical parameters corresponding to the capacitor or the neutral line are abnormal, the target electrical parameters can be effectively controlled within a reasonable range, thereby reducing the shutdown frequency of the inverter system, ensuring the normal operation of the inverter system, extending the service life of the inverter system, improving the user experience, and being applicable to a wide range of inverter scenarios.

[0149] The control logic corresponding to the capacitor and the neutral line is explained below respectively.

[0150] 1. Control logic corresponding to capacitor

[0151] In some embodiments, when the target electrical parameter includes at least one of a capacitor ripple voltage and load information corresponding to each phase line of the inverter system, the target threshold includes a first threshold, and step 120 may include:

[0152] When the capacitor ripple voltage exceeds a first threshold value and / or when it is determined based on the load information that the loads of the phases are unbalanced, the bus voltage of the inverter system is increased to reduce the target electrical parameter.

[0153] In this embodiment, the first threshold is less than the capacitance specification.

[0154] The first threshold may be user-defined or adaptively adjusted based on the temperature of the inverter system.

[0155] When the output of each phase is unbalanced, such as when the off-grid is unbalanced with load or the grid-connected three-phase power is unbalanced, the capacitor ripple voltage becomes larger, and there is a possibility that the capacitor ripple voltage exceeds the capacitor specification.

[0156] In the actual implementation process, it is possible to directly determine whether the loads of each phase of the inverter system are balanced based on the load information;

[0157] For example, for a multi-phase inverter system, the maximum current and the minimum current in the phase current of each phase can be obtained, and whether the load is balanced is determined by judging the difference between the maximum current and the minimum current. When the difference is small, it can be approximately considered that the load is balanced, in which case there is no need to change the capacitor ripple voltage; when the difference is large, it is considered that the load is unbalanced, in which case the capacitor ripple voltage needs to be reduced.

[0158] In some embodiments, it can also be determined by the size of the capacitor ripple voltage.

[0159] For example, when the capacitor ripple voltage is not greater than the first threshold, it is considered that the possibility of the capacitor ripple voltage exceeding the capacitor specification is low, and in this case, the capacitor ripple voltage does not need to be changed; and when the capacitor ripple voltage is greater than the first threshold, it is considered that there is a certain possibility that the capacitor ripple voltage may exceed the capacitor specification, and in this case, the capacitor ripple voltage needs to be reduced. The capacitor ripple voltage can be reduced by increasing the bus voltage of the inverter system.

[0160] like Figure 3 As shown, at time t1, the capacitor ripple voltage exceeds the first threshold Ur1a, and the inverter system raises the operating bus voltage from Udc1 to Udc2; then the capacitor ripple voltage decreases and reaches a steady state at time t2.

[0161] In some embodiments, after increasing the bus voltage of the inverter system, the method may further include:

[0162] When the capacitor ripple voltage is less than the sixth threshold, the bus voltage is reduced.

[0163] In this embodiment, the sixth threshold is smaller than the first threshold.

[0164] The sixth threshold may be based on user customization.

[0165] Continue to refer Figure 3At time t1, the capacitor ripple voltage (i.e., half bus ripple) exceeds the first threshold Ur1a, and the inverter system raises the operating bus voltage from Udc1 to Udc2, increasing ΔUdc; then the capacitor ripple voltage decreases and reaches a steady state at time t2, keeping the bus voltage unchanged at Udc2; when the capacitor ripple voltage further decreases due to reasons such as load reduction, after it is less than the sixth threshold Ur1b at time t3, the control logic of raising the bus voltage is exited, and the bus voltage decreases.

[0166] The principle of increasing the bus voltage of the inverter system to reduce the target electrical parameters is described below.

[0167] like Fig.12 As shown, assuming that the current A-phase output current is Ia and is positive, the output voltage command is Ua and is positive, the inverter switching period is T, the positive and negative bus capacitors C1 / C2 voltages are Upos and Uneg respectively, and the capacitance is C; then the output duty cycle is:

[0168]

[0169] That is, within the switching cycle T, the output high level time is:

[0170]

[0171] When the output is high level, the upper tube Sa1 and the horizontal tube Sa3 are turned on, the lower tube Sa4 and the horizontal tube Sa2 are turned off, and the current loop is: positive bus capacitor C1~upper tube Sa1~inverter inductor La~load~bus midpoint O.

[0172] In this process, ignoring the charging process of the bus capacitor by the external voltage, the current flows out from the positive electrode of the positive bus capacitor and then flows back to the negative electrode, that is, the positive bus is discharged, and the discharge amount is:

[0173]

[0174] In the switching period T, the output zero level time is:

[0175]

[0176] When the output is zero level, the cross tubes Sa2 and Sa3 are turned on, and the upper tube Sa1 and the lower tube Sa4 are turned off. At this time, the current loop is: bus midpoint O~cross tube~cross tube~inverter inductor La~load~bus midpoint O.

[0177] During this process, neither the positive nor negative bus capacitors are discharged to the outside.

[0178] It can be seen that in the above process, the positive bus capacitor discharges ΔQ only when the output is high. According to the relationship between capacitor voltage and quantity, the change in the positive bus capacitor voltage caused by discharge is:

[0179]

[0180] Substituting in, the positive bus capacitor voltage change during the switching cycle is:

[0181]

[0182] It can be seen that the voltage change of the positive bus capacitor is inversely proportional to the voltage Upos of the positive bus capacitor. The higher the voltage, the smaller the voltage change.

[0183] Based on the above inference, it can be seen that the higher the bus voltage, the smaller the capacitor ripple voltage under the same output conditions.

[0184] The specific implementation method of increasing the bus voltage of the inverter system is described below.

[0185] First, test and adjust

[0186] In some embodiments, increasing the bus voltage of the inverter system to reduce the target electrical parameter may include:

[0187] The bus voltage of the inverter system is increased until the newly acquired capacitor ripple voltage does not exceed the first threshold.

[0188] In this embodiment, while increasing the bus voltage of the inverter system, the capacitor ripple voltage can be collected in real time until the capacitor ripple voltage does not exceed the first threshold, then the bus voltage is stopped from being increased, and the bus voltage is controlled to maintain the current value unchanged.

[0189] Second, adjustment based on preset relationships

[0190] In some embodiments, increasing the bus voltage of the inverter system to reduce the target electrical parameter may include:

[0191] Based on a first correlation between a change in the capacitor ripple voltage and the bus voltage, determining to reduce the capacitor ripple voltage to a first target value of the bus voltage corresponding to a first threshold; the first correlation is predetermined;

[0192] The bus voltage is increased to a first target value.

[0193] In this embodiment, the first association relationship is predetermined and can be expressed as a relational expression or a relational table.

[0194] Taking the first correlation as an example, a relationship between the change in capacitor ripple voltage and the bus voltage can be established in advance based on test data. In actual application, the difference between the capacitor ripple voltage and the first threshold is calculated, and the difference is substituted into the relationship to obtain the first target value corresponding to the bus voltage when the capacitor ripple voltage is reduced to the first threshold, so as to increase the bus voltage to the first target value.

[0195] Third, PI regulation

[0196] In some embodiments, increasing the bus voltage of the inverter system to reduce the target electrical parameter may include:

[0197] Determining a first PI control target based on an operating parameter of the inverter system and a reference value of a capacitor ripple voltage;

[0198] Based on the first PI control target, the bus voltage of the inverter system is increased.

[0199] In this embodiment, the operating parameters are used to characterize the real-time operating conditions of the inverter system.

[0200] The operating parameters may include: bus voltage or temperature, etc.

[0201] The first PI control target may change accordingly based on the real-time operating conditions.

[0202] Fourth, gradient derating

[0203] In some embodiments, increasing the bus voltage of the inverter system to reduce the target electrical parameter may include:

[0204] In a case where the capacitor ripple voltage is greater than a reference value of the capacitor ripple voltage, increasing a bus voltage of the inverter system based on a first rate;

[0205] When the capacitor ripple voltage is not greater than a reference value of the capacitor ripple voltage, the bus voltage of the inverter system is reduced based on a second rate.

[0206] In this embodiment, the reference value of the capacitor ripple voltage may be user-defined.

[0207] The reference value of the capacitor ripple voltage may change accordingly with changes in the real-time operating conditions of the inverter system, such as changes based on bus voltage or temperature.

[0208] The specific values ​​of the first rate and the second rate can be customized based on the user, such as setting the first rate to 1V / s, 2V / s or other values, and setting the second rate to 0.1V / s, 0.2V / s or other values, etc., which are not limited in this application.

[0209] For example, when the capacitor ripple voltage Uact>the reference value Uref of the capacitor ripple voltage, the bus voltage of the inverter system is increased based on a first rate, such as increasing the bus voltage of the inverter system based on a rate of 1 V / s;

[0210] When the capacitor ripple voltage Uact is less than the reference value Uref of the capacitor ripple voltage, the bus voltage of the inverter system is reduced based on the second rate, such as reducing the bus voltage of the inverter system at a rate of 0.1V / s, and the cycle is repeated, so that the capacitor ripple voltage can be stably maintained near the reference value of the capacitor ripple voltage for a long time, thereby ensuring that the inverter output is maximized as much as possible.

[0211] According to the control method of the inverter system provided in the embodiment of the present application, by providing multiple bus voltage adjustment methods, the best method can be selected based on actual conditions, which has high flexibility and universality.

[0212] In some embodiments, increasing the bus voltage of the inverter system to reduce the target electrical parameter may include:

[0213] The bus voltage of the inverter system is increased to reduce the target electrical parameter without triggering bus voltage derating and / or overvoltage protection of the inverter system.

[0214] In this embodiment, in the process of increasing the bus voltage of the inverter system, it should also be ensured that the bus derating or overvoltage protection of the inverter system is not triggered due to the increase of the bus voltage.

[0215] According to the control method of the inverter system provided in the embodiment of the present application, by increasing the bus voltage of the inverter system to reduce the target electrical parameters while simultaneously satisfying the bus voltage derating and overvoltage protection of the inverter system without triggering it, the stable operation of the inverter system can be effectively guaranteed, and the user experience can be further improved.

[0216] In some embodiments, when the target electrical parameter includes a capacitor ripple voltage, the target threshold includes a second threshold, and step 120 may include:

[0217] When the capacitor ripple voltage exceeds the second threshold, the output electrical signal of the inverter system is reduced, and the output electrical signal includes output current or output power.

[0218] In this embodiment, the output electrical signal includes: output current or output power.

[0219] The second threshold is less than the capacitance specification.

[0220] The second threshold may be based on user customization.

[0221] In some embodiments, the second threshold may also be adaptively adjusted based on the temperature of the inverter system.

[0222] In the actual implementation process, when the capacitor ripple voltage exceeds the second threshold, the output current or output power of the inverter system is reduced to reduce the capacitor ripple voltage.

[0223] like Figure 4 As shown, at time t1, the capacitor ripple voltage rises to be higher than the second threshold Ur2a and starts to decrease in rating.

[0224] Taking the reduction of output current as an example, it starts to decrease from the initial value Imax1. At time t2, the adjustment reaches a steady state, the capacitor ripple voltage is no higher than the second threshold Ur2a, and the corresponding output current limit value reaches stability and no longer decreases. The inverter system uses this current as the maximum output current.

[0225] In some embodiments, after reducing the output electrical signal of the inverter system, the method may further include:

[0226] When the ripple voltage is less than the seventh threshold, the output electrical signal is increased to an initial value.

[0227] In this embodiment, the seventh threshold is smaller than the second threshold.

[0228] The seventh threshold may be user-defined.

[0229] The initial value is the output signal of the inverter system before derating.

[0230] Continue to refer Figure 4 At time t3, due to load reduction and other reasons, the capacitor ripple voltage decreases and is less than the seventh threshold Ur2b. At this time, it is no longer necessary to limit the output current derating, and the maximum output current limit is controlled to return to Imax1.

[0231] According to the control method of the inverter system provided in the embodiment of the present application, when the capacitor ripple voltage is high, the capacitor ripple voltage can be reduced by derating and / or adjusting the bus voltage of the inverter system, etc., with high adjustment precision and accuracy, and can effectively reduce the capacitor ripple voltage to a reasonable range, thereby extending the life of the capacitor and reducing the risk of capacitor failure, thereby extending the service life of the inverter system; in addition, it can also reduce the frequency of the inverter system shutting down due to faults, thereby improving the user experience.

[0232] The specific control method of inverter derating is described below.

[0233] First, test and adjust

[0234] In some embodiments, reducing the output electrical signal of the inverter system may include:

[0235] The output electrical signal of the inverter system is reduced until the capacitor ripple voltage corresponding to the newly acquired capacitor does not exceed the second threshold value.

[0236] In this embodiment, while reducing the output electrical signal of the inverter system, the capacitor ripple voltage can be collected in real time until the capacitor ripple voltage does not exceed the second threshold value, then the reduction of the output electrical signal of the inverter system is stopped, and the output electrical signal of the inverter system is controlled to maintain the current value unchanged.

[0237] Second, PI regulation

[0238] In some embodiments, reducing the output electrical signal of the inverter system may include:

[0239] Determining a second PI control target based on an operating parameter of the inverter system and a reference value of a capacitor ripple voltage;

[0240] Based on the second PI control target, the output electrical signal of the inverter system is reduced.

[0241] In this embodiment, the operating parameters are used to characterize the real-time operating conditions of the inverter system.

[0242] The operating parameters may include: bus voltage or temperature, etc.

[0243] The second PI control target can be changed based on the real-time operating conditions.

[0244] For example, a second PI control target of derating is set, and the second PI control target can change with the working conditions, such as following the corresponding changes of the bus voltage or temperature. For example, the reference value of the capacitor ripple voltage is set to Uref, and the difference can be calculated according to the capacitor ripple voltage reference value Uref and the actual feedback Uact (that is, the capacitor ripple voltage collected in real time), and then calculated by the PID controller to output the inverter current limit or power limit, wherein the transfer function of the PID controller is:

[0245]

[0246] in, is the proportional adjustment coefficient, is the integral adjustment coefficient, is the differential adjustment coefficient, is a complex variable.

[0247] Third, adjustment based on preset relationships

[0248] In some embodiments, reducing the output electrical signal of the inverter system may include:

[0249] Based on a second correlation between a change in the capacitor ripple voltage and an output electrical signal of the inverter system, determining to reduce the capacitor ripple voltage to a second target value of the output electrical signal corresponding to a second threshold; the second correlation is predetermined;

[0250] The output electrical signal is reduced to a second target value.

[0251] In this embodiment, the second association relationship is predetermined and can be expressed as a relational expression or a relational table.

[0252] Taking the second association relationship as a relationship table as an example, a relationship table between the capacitor ripple voltage and the output electrical signal of the inverter system under different working conditions (such as different temperatures) can be established in advance based on theoretical calculations or test data, as shown in Table 1.

[0253] In actual application, by comparing and interpolating with the data in the table, the corresponding inverter current limit can be obtained to limit the inverter output current.

[0254] When the current capacitor ripple voltage is 30V, according to the relationship table, the output current limit of the inverter system is 30A.

[0255] For another example, when the current capacitor ripple voltage is 40V, linear interpolation is performed according to the relationship table, and it can be obtained that the output current limit of the inverter system is 20A.

[0256] Table 1

[0257]

[0258] Fourth, gradient derating

[0259] In some embodiments, reducing the output electrical signal of the inverter system may include:

[0260] When the capacitor ripple voltage is greater than a reference value of the capacitor ripple voltage, reducing the output electrical signal of the inverter system based on a third rate;

[0261] When the capacitor ripple voltage is not greater than a reference value of the capacitor ripple voltage, the output electrical signal of the inverter system is increased based on a fourth rate.

[0262] In this embodiment, the reference value of the capacitor ripple voltage is greater than the second threshold.

[0263] The reference value of the capacitor ripple voltage may change accordingly with changes in the real-time operating conditions of the inverter system, such as changes based on bus voltage or temperature.

[0264] The specific values ​​of the third rate and the fourth rate can be based on user customization, such as setting the third rate to 1A / s, 2A / s or other values, and setting the fourth rate to 0.1A / s, 0.2A / s or other values, etc., which are not limited in this application.

[0265] For example, when the capacitor ripple voltage Uact>the reference value Uref of the capacitor ripple voltage, the output current or output power limit of the inverter system is reduced based on the third rate, such as reducing the output current limit of the inverter system based on a speed of 1 A / s;

[0266] When the capacitor ripple voltage Uact is less than the reference value Uref of the capacitor ripple voltage, the output current or output power limit of the inverter system is increased based on the fourth rate, such as increasing the output current limit of the inverter system at a rate of 0.1A / s, and the cycle is repeated, so that the capacitor ripple voltage can be stably maintained near the reference value of the capacitor ripple voltage for a long time, thereby ensuring that the inverter output is maximized as much as possible.

[0267] According to the control method of the inverter system provided in the embodiment of the present application, by providing multiple derating methods, the best method can be selected based on actual conditions, which has high flexibility and universality.

[0268] In some embodiments, when the target electrical parameter includes a capacitor ripple voltage, the target threshold includes a third threshold, and step 120 may include:

[0269] When the capacitor ripple voltage exceeds a third threshold, the inverter system is controlled to shut down; the third threshold is greater than the first threshold and the third threshold is greater than the second threshold.

[0270] In this embodiment, the third threshold is greater than the first threshold and the third threshold is greater than the second threshold.

[0271] The third threshold may be slightly less than the capacitance specification.

[0272] In the actual implementation process, when it is determined that the capacitor ripple voltage exceeds the third threshold, if the capacitor ripple voltage cannot be effectively controlled within a reasonable range by raising the bus voltage of the inverter system or derating the inverter, the inverter system shutdown protection is triggered and the inverter does not output externally.

[0273] According to the control method of the inverter system provided in the embodiment of the present application, by controlling the inverter system to shut down when the capacitor ripple voltage exceeds the third threshold value, it is possible to add a bottom-line protection measure to shut down the inverter system for protection when other adjustment measures fail in the case of inverter abnormality, thereby reducing the safety risks caused by abnormal operation and extending the service life of the inverter system.

[0274] 2. Control logic corresponding to the center line

[0275] In some embodiments, when the target electrical parameter includes a detection signal of a neutral line, the target threshold includes a fourth threshold; step 120 may include:

[0276] When the detection signal exceeds a fourth threshold, the output electrical signal of the inverter system is reduced to reduce the detection signal.

[0277] In this embodiment, the detection signal may include: neutral current or temperature information associated with the neutral current.

[0278] The output electrical signal may include: output current or output power.

[0279] The fourth threshold may be based on user customization.

[0280] It should be noted that the fourth threshold should be consistent with the category of the detection signal.

[0281] In some embodiments, the fourth threshold may include a first sub-threshold or a second sub-threshold, wherein the first sub-threshold is of current type and is used to determine the neutral current; and the second sub-threshold is of temperature type and is used to determine temperature information associated with the neutral current.

[0282] In actual implementation, when the detection signal exceeds the fourth threshold, the inverter system is derated, such as reducing the output current or output power of the inverter system to reduce the detection signal.

[0283] The specific adjustment method is similar to the derating adjustment method corresponding to the capacitor, and will not be described in detail in this application.

[0284] In some embodiments, after reducing the output electrical signal of the inverter system, the method may further include:

[0285] When the detection signal is less than the eighth threshold, the output electrical signal of the inverter system is increased to an initial value.

[0286] In this embodiment, the eighth threshold is smaller than the fourth threshold.

[0287] like Figure 5 As shown, at time t1, since the N-line current (i.e., the neutral line current) rises above the fourth threshold value Ira, the derating starts to decrease;

[0288] Taking the reduction of output current as an example, it starts to decrease from the initial value Imax1. At time t2, the adjustment reaches a steady state, the N-line current is no higher than the first sub-threshold Ira, and the corresponding output current limit value reaches stability and no longer decreases. The inverter uses this current as the maximum output current. At time t3, due to reasons such as load reduction, the N-line current decreases and is less than the eighth threshold Irb. At this time, there is no need to limit the output current derating, and the output maximum current limit returns to Imax1.

[0289] According to the control method of the inverter system provided in the embodiment of the present application, by reducing the output current or output power of the inverter system to reduce the detection signal when the detection signal exceeds the fourth threshold, the detection signal can be effectively reduced to a reasonable range with high control precision and accuracy, thereby extending the service life of the inverter system.

[0290] In some embodiments, when the target electrical parameter includes a detection signal of a neutral line, the target threshold includes a fifth threshold; step 120 may include:

[0291] When the detection signal exceeds a fifth threshold, the inverter system is controlled to shut down; the fifth threshold is greater than the fourth threshold.

[0292] In this embodiment, the fifth threshold is greater than the fourth threshold.

[0293] The fifth threshold may be based on user customization.

[0294] In the actual implementation process, when the detection signal exceeds the fifth threshold, the inverter system is controlled to shut down.

[0295] It can be understood that in some embodiments, when the detection signal exceeds the fourth threshold, the output current or output power of the inverter system can be reduced first to reduce the detection signal. If the output current or output power of the inverter system still cannot be reduced to a reasonable range, the inverter system can be controlled to shut down.

[0296] The above embodiment is described below by taking the case where the detection signal is temperature information associated with the neutral current as an example.

[0297] In actual implementation, the neutral current may not be adjusted directly, but the neutral current protection may be achieved by derating the temperature information that can reflect the neutral current.

[0298] For example, the neutral current may be indirectly controlled by controlling temperature information associated with the neutral current. The larger the neutral current, the higher the associated temperature; the smaller the neutral current, the lower the associated temperature.

[0299] like Fig.11As shown, at time t1, the temperature reflecting the neutral current (such as the temperature of the neutral terminal or the balancing bridge temperature) rises to above the second sub-threshold Tra, so the output current limit begins to be reduced from the initial value Imax1. At time t2, the adjustment reaches a steady state, the temperature is not higher than the second sub-threshold Tra, the corresponding output current limit value reaches stability and no longer decreases, and the inverter uses this current as the maximum output current; at time t3, due to reasons such as load reduction, the temperature decreases and is less than the ninth threshold Trb. At this time, there is no need to reduce the output current, and the output maximum current limit returns to Imax1; in the process, since the neutral current is related to the temperature, the neutral current can be indirectly limited to not exceed the set value by controlling the temperature.

[0300] According to the control method of the inverter system provided in the embodiment of the present application, by controlling the inverter system to shut down when the detection signal exceeds the fifth threshold value, it is possible to add a bottom-line protection measure to shut down the inverter system for protection when other adjustment measures fail in the case of inverter abnormality, thereby reducing the safety risks caused by abnormal operation and extending the service life of the inverter system.

[0301] The control method of the inverter system provided in the embodiment of the present application may be executed by a control device of the inverter system. In the embodiment of the present application, the control device of the inverter system executing the control method of the inverter system is taken as an example to illustrate the control device of the inverter system provided in the embodiment of the present application.

[0302] An embodiment of the present application also provides a control device for an inverter system.

[0303] The inverter system includes a plurality of capacitors connected in series, wherein the plurality of capacitors connected in series are connected between positive and negative busbars, and a neutral point between the plurality of capacitors connected in series is connected to a neutral line of the inverter system.

[0304] like Figure 6 As shown, the control device of the inverter system includes: a first processing module 610 and a second processing module 620 .

[0305] The first processing module 610 is used to obtain target electrical parameters corresponding to target objects in the capacitor and the neutral line, where the target electrical parameters include at least one of the capacitor ripple voltage, the load information corresponding to each phase line of the inverter system, and the detection signal of the neutral line; the detection signal is a signal used to characterize the magnitude of the neutral line current of the neutral line;

[0306] The second processing module 620 is used to execute a control logic corresponding to the target electrical parameter based on the target threshold and the target electrical parameter to reduce the target electrical parameter.

[0307] According to the control device of the inverter system provided in the embodiment of the present application, by executing the control logic corresponding to the target electrical parameters to reduce the target electrical parameters when the target electrical parameters corresponding to the capacitor or the neutral line are abnormal, the target electrical parameters can be effectively controlled within a reasonable range, thereby reducing the shutdown frequency of the inverter system, ensuring the normal operation of the inverter system, extending the service life of the inverter system, and improving the user experience.

[0308] In some embodiments, when the target electrical parameter includes at least one of a capacitor ripple voltage and load information corresponding to each phase line of the inverter system, the target threshold includes a first threshold; the second processing module 620 may also be used to:

[0309] When the capacitor ripple voltage exceeds a first threshold value and / or when it is determined based on the load information that the loads of the phases are unbalanced, the bus voltage of the inverter system is increased to reduce the target electrical parameter.

[0310] In some embodiments, the second processing module 620 may also be used to:

[0311] Increasing the bus voltage of the inverter system until the newly acquired capacitor ripple voltage does not exceed a first threshold;

[0312] or,

[0313] Based on a first correlation between a change in the capacitor ripple voltage and the bus voltage, determining to reduce the capacitor ripple voltage to a first target value of the bus voltage corresponding to a first threshold; the first correlation is predetermined;

[0314] increasing the bus voltage to a first target value;

[0315] or,

[0316] Determining a first PI control target based on an operating parameter of the inverter system and a reference value of a capacitor ripple voltage;

[0317] Based on the first PI control target, increasing the bus voltage of the inverter system;

[0318] or,

[0319] In a case where the capacitor ripple voltage is greater than a reference value of the capacitor ripple voltage, increasing a bus voltage of the inverter system based on a first rate;

[0320] When the capacitor ripple voltage is not greater than a reference value of the capacitor ripple voltage, the bus voltage of the inverter system is reduced based on a second rate.

[0321] In some embodiments, the second processing module 620 may also be used to:

[0322] The bus voltage of the inverter system is increased to reduce the target electrical parameter without triggering bus voltage derating and / or overvoltage protection of the inverter system.

[0323] In some embodiments, the apparatus may further include a third processing module, configured to:

[0324] Obtain the actual ripple voltage of each capacitor in the target cycle;

[0325] A maximum value among the multiple actual ripple voltages, or an average value corresponding to the multiple actual ripple voltages, is determined as the capacitor ripple voltage.

[0326] In some embodiments, when the target electrical parameter includes a capacitor ripple voltage, the target threshold includes a second threshold; the second processing module 620 may also be used to:

[0327] When the capacitor ripple voltage exceeds the second threshold, the output electrical signal of the inverter system is reduced, and the output electrical signal includes output current or output power.

[0328] In some embodiments, the second processing module 620 may also be used to:

[0329] reducing the output electrical signal of the inverter system until the capacitor ripple voltage corresponding to the newly acquired capacitor does not exceed a second threshold value;

[0330] or,

[0331] Based on a second correlation between a change in the capacitor ripple voltage and an output electrical signal of the inverter system, determining to reduce the capacitor ripple voltage to a second target value of the output electrical signal corresponding to a second threshold; the second correlation is predetermined;

[0332] reducing the output electrical signal to a second target value;

[0333] or,

[0334] Determining a second PI control target based on an operating parameter of the inverter system and a reference value of a capacitor ripple voltage;

[0335] Based on the second PI control target, reducing the output electrical signal of the inverter system;

[0336] or,

[0337] When the capacitor ripple voltage is greater than a reference value of the capacitor ripple voltage, reducing the output electrical signal of the inverter system based on a third rate;

[0338] When the capacitor ripple voltage is not greater than a reference value of the capacitor ripple voltage, the output electrical signal of the inverter system is increased based on a fourth rate.

[0339] In some embodiments, when the target electrical parameter includes a capacitor ripple voltage, the target threshold includes a third threshold; the second processing module 620 may also be used to:

[0340] When the capacitor ripple voltage exceeds a third threshold, the inverter system is controlled to shut down; the third threshold is greater than the first threshold and the third threshold is greater than the second threshold.

[0341] In some embodiments, the apparatus may further include a fourth processing module for dynamically adjusting the target threshold based on at least one of a temperature of the inverter system and a temperature of the neutral terminal.

[0342] In some embodiments, the fourth processing module may also be used to:

[0343] When the temperature is greater than a first temperature threshold, reducing the target threshold;

[0344] When the temperature is less than a second temperature threshold, the target threshold is increased; wherein the second temperature threshold is less than the first temperature threshold.

[0345] In some embodiments, when the target electrical parameter includes a detection signal of a neutral line, the target threshold includes a fourth threshold; the second processing module 620 may also be used to:

[0346] When the detection signal exceeds a fourth threshold, the output electrical signal of the inverter system is reduced to reduce the detection signal, and the output electrical signal includes an output current or an output power.

[0347] In some embodiments, when the target electrical parameter includes a detection signal of a neutral line, the target threshold includes a fifth threshold; the second processing module 620 may also be used to:

[0348] When the detection signal exceeds a fifth threshold, the inverter system is controlled to shut down; the fifth threshold is greater than the fourth threshold.

[0349] The control device of the inverter system in the embodiment of the present application may be an electronic device or a component in the electronic device, such as an integrated circuit or a chip. The electronic device may be a terminal or other devices other than a terminal. Exemplarily, the electronic device may be a mobile phone, a tablet computer, a laptop computer, a PDA, a vehicle-mounted electronic device, a mobile Internet device (Mobile Internet Device, MID), an augmented reality (augmented reality, AR) / virtual reality (virtual reality, VR) device, a robot, a wearable device, an ultra-mobile personal computer (ultra-mobile personal computer, UMPC), a netbook or a personal digital assistant (personal digital assistant, PDA), etc. It may also be a server, a network attached storage (Network Attached Storage, NAS), a personal computer (personal computer, PC), a television (television, TV), a teller machine or a self-service machine, etc., which is not specifically limited in the embodiment of the present application.

[0350] The control device of the inverter system in the embodiment of the present application may be a device having an operating system. The operating system may be an Android operating system, an IOS operating system, or other possible operating systems, which are not specifically limited in the embodiment of the present application.

[0351] The control device of the inverter system provided in the embodiment of the present application can achieve Figures 1 to 5 To avoid repetition, the various processes implemented by the method embodiment are not described here.

[0352] An embodiment of the present application also provides an inverter system based on the control method of the inverter system described in any of the above embodiments.

[0353] like Figure 7 As shown, the inverter system includes: an inverter circuit, a plurality of capacitors connected in series and at least one phase line.

[0354] Among them, the inverter circuit is connected to the DC voltage through the positive and negative bus bars.

[0355] A plurality of capacitors connected in series are connected between the positive and negative busbars, and a neutral point between the plurality of capacitors connected in series is connected to a neutral line of the inverter system.

[0356] The number of capacitors may be 2, 4, 6 or other numbers.

[0357] Figure 8 An example circuit structure of two capacitors connected in series is shown.

[0358] Fig. 9 An example circuit structure of four capacitors connected in series is shown.

[0359] The output end of the inverter circuit is connected to at least one phase line.

[0360] The inverter system may be a single-phase inverter system or a multi-phase inverter system.

[0361] The inverter system may be a multi-level inverter, including but not limited to: a three-level inverter, a five-level inverter, and other multi-level inverters.

[0362] Fig. 9 An example of a single-phase bridge arm schematic of a five-level inverter is shown.

[0363] Fig.13 and Fig.14 A schematic diagram of a two-phase bridge arm inverter of a three-level inverter is illustrated respectively.

[0364] The inverter system is adjusted based on the control method of the inverter system described in any of the above embodiments, which will not be described in detail in this application.

[0365] According to the inverter system provided in the embodiment of the present application, by executing the control logic corresponding to the target electrical parameters to reduce the target electrical parameters when the target electrical parameters corresponding to the capacitor or the neutral line are abnormal, the target electrical parameters can be effectively controlled within a reasonable range, thereby reducing the shutdown frequency of the inverter system, ensuring the normal operation of the inverter system, extending the service life of the inverter system, and improving the user experience.

[0366] In some embodiments, Fig.10 As shown, an embodiment of the present application further provides an electronic device 1000, including a processor 1001, a memory 1002, and a computer program stored in the memory 1002 and executable on the processor 1001. When the program is executed by the processor 1001, each process of the control method embodiment of the above-mentioned inverter system is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be described here.

[0367] It should be noted that the electronic devices in the embodiments of the present application include the mobile electronic devices and non-mobile electronic devices mentioned above.

[0368] An embodiment of the present application also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the various processes of the control method embodiment of the above-mentioned inverter system are implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0369] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory ROM, a random access memory RAM, a magnetic disk or an optical disk.

[0370] An embodiment of the present application also provides a computer program product, including a computer program, which implements the control method of the inverter system when executed by a processor.

[0371] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory ROM, a random access memory RAM, a magnetic disk or an optical disk.

[0372] An embodiment of the present application further provides a chip, which includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the various processes of the above-mentioned inverter system control method embodiment, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0373] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0374] It should be noted that, in this article, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0375] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a computer software product, which is stored in a storage medium (such as ROM / RAM, a disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0376] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

[0377] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0378] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A control method for an inverter system, characterized in that: The inverter system includes a plurality of capacitors connected in series, the plurality of capacitors connected in series are connected between positive and negative busbars, a neutral point between the plurality of capacitors connected in series is connected to a neutral line of the inverter system, and an output end of the inverter system is connected to at least one phase line; the method includes: Acquire a target electrical parameter corresponding to the center line target object, wherein the target electrical parameter includes a detection signal of the center line; the detection signal is a signal used to characterize the magnitude of the center line current of the center line; Based on the target threshold and the target electrical parameter, executing a control logic corresponding to the target electrical parameter to reduce the target electrical parameter; The target threshold is dynamically adjusted based on at least one of a temperature of the inverter system and a temperature of a neutral terminal; In a case where the target electrical parameter includes the detection signal of the midline, the target threshold includes a fourth threshold; and based on the target threshold and the target electrical parameter, executing a control logic corresponding to the target electrical parameter to reduce the target electrical parameter comprises: When the detection signal exceeds the fourth threshold, reducing the output electrical signal of the inverter system to reduce the detection signal, the output electrical signal including output current or output power; The other end of the neutral line of the inverter system is grounded and connected to the output end of the phase line; Reducing the detection signal by triggering inverter derating; After reducing the output electrical signal of the inverter system, the method further includes: when the detection signal is not higher than the fourth threshold value and not lower than the eighth threshold value, controlling the output electrical signal to remain unchanged; when the detection signal is lower than the eighth threshold value, increasing the output electrical signal of the inverter system to an initial value; the initial value is the output electrical signal of the inverter system before the derating is performed; The eighth threshold is smaller than the fourth threshold.

2. The control method of the inverter system according to claim 1, characterized in that: The target threshold is dynamically adjusted based on at least one of a temperature of the inverter system and a temperature of a neutral terminal, including: When the temperature is greater than a first temperature threshold, reducing the target threshold; When the temperature is less than a second temperature threshold, the target threshold is increased; wherein the second temperature threshold is less than the first temperature threshold.

3. The control method of the inverter system according to claim 1, characterized in that: In the case where the target electrical parameter includes the detection signal of the center line, the target threshold value includes a fifth threshold value; The executing, based on the target threshold and the target electrical parameter, a control logic corresponding to the target electrical parameter to reduce the target electrical parameter comprises: When the detection signal exceeds the fifth threshold, controlling the inverter system to shut down; The fifth threshold is greater than the fourth threshold.

4. A control device for an inverter system, characterized in that: The inverter system includes a plurality of capacitors connected in series, the plurality of capacitors connected in series are connected between positive and negative busbars, a neutral point between the plurality of capacitors connected in series is connected to a neutral line of the inverter system, and an output end of the inverter system is connected to at least one phase line; the device includes: A first processing module is used to obtain a target electrical parameter corresponding to the center line target object, wherein the target electrical parameter includes a detection signal of the center line; the detection signal is a signal used to characterize the magnitude of the center line current of the center line; A second processing module, configured to execute a control logic corresponding to the target electrical parameter to reduce the target electrical parameter based on the target threshold and the target electrical parameter; The target threshold is dynamically adjusted based on at least one of a temperature of the inverter system and a temperature of a neutral terminal; In the case where the target electrical parameter includes the detection signal of the neutral line, the target threshold includes a fourth threshold; and the second processing module is further configured to: When the detection signal exceeds the fourth threshold, reducing the output electrical signal of the inverter system to reduce the detection signal, the output electrical signal including output current or output power; The other end of the neutral line of the inverter system is grounded and connected to the output end of the phase line; The second processing module is further used to: reduce the detection signal by triggering inverter derating; The second processing module is further configured to: after reducing the output electrical signal of the inverter system, further include: when the detection signal is not higher than the fourth threshold value and not lower than the eighth threshold value, control the output electrical signal to remain unchanged; when the detection signal is lower than the eighth threshold value, increase the output electrical signal of the inverter system to an initial value; the initial value is the output electrical signal of the inverter system before the derating is performed; The eighth threshold is smaller than the fourth threshold.

5. An inverter system based on the control method of the inverter system according to any one of claims 1 to 3, characterized in that: include: An inverter circuit, wherein the inverter circuit is connected to a DC voltage via positive and negative bus bars; A plurality of capacitors connected in series, wherein the plurality of capacitors connected in series are connected between the positive and negative busbars, and a neutral point between the plurality of capacitors connected in series is connected to a neutral line of the inverter system; at least one phase line, the output end of the inverter circuit being connected to the at least one phase line; The other end of the neutral line of the inverter system is grounded and connected to the output end of the phase line.

6. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the control method of the inverter system as claimed in any one of claims 1 to 3 is implemented.

7. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the control method of the inverter system according to any one of claims 1 to 3 is implemented.

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