Operation control method and device of power converter, inverter, medium and product

Abstract

The invention relates to an operation control method and device of a power converter, an inverter, a medium and a product. The method comprises the following steps: when the power converter operates in a burst mode, judging whether the current direct-current voltage of a direct-current side circuit connected with the power converter meets an operation control condition or not; if it is determined that the operation control condition is met, the operation process of the burst mode is controlled; wherein the operation process is controlled by stopping the burst mode or adjusting the output power of the power converter. The method can ensure the stable operation of the system where the power converter is located.

Description

Technical Field

[0001] The present application relates to the field of circuit control technology, and in particular to an operation control method, device, inverter, medium and product of a power converter. Background Art

[0002] Power converter is a commonly used power conversion device. Some power converters can convert direct current into alternating current. Taking the conversion of photovoltaic direct current into alternating current as an example, under low light conditions, the AC output of the power converter is small, the efficiency of the power converter is reduced, and the current distortion rate increases. If the power converter works in burst mode (also called Burst mode), various problems caused by insufficient light intensity can be reduced.

[0003] However, when the power converter operates in the burst mode, the DC voltage fluctuation may easily cause the working efficiency of the power converter to decrease, thereby affecting the stability of the operation of the system in which the power converter is located. Summary of the invention

[0004] Based on this, it is necessary to provide a power converter operation control method, device, inverter, medium and product that can ensure stable operation of the system in which the power converter is located in order to solve the above technical problems.

[0005] In a first aspect, the present application provides an operation control method of a power converter. The method comprises:

[0006] When the power converter is operating in the burst mode, determining whether a current DC voltage of a DC side circuit connected to the power converter satisfies an operating control condition;

[0007] If it is determined that the operation control condition is met, the operation process of the burst mode is controlled; wherein controlling the operation process includes stopping the burst mode or adjusting the output power of the power converter.

[0008] In one of the embodiments, the operation control condition includes a power adjustment condition; the power adjustment condition is determined by a voltage fluctuation range; judging whether a current DC voltage of a DC side circuit connected to a power converter satisfies the operation control condition, including: if the current DC voltage does not belong to the voltage fluctuation range, determining that the current DC voltage satisfies the power adjustment condition; controlling the operation process of the burst mode, including: adjusting the output power of the power converter.

[0009] In one embodiment, the voltage fluctuation range is determined by:

[0010] Determine the average DC voltage of the DC side circuit during the historical operation stage; determine the voltage fluctuation range based on the average DC voltage and the preset fluctuation voltage.

[0011] In one embodiment, the output power of the power converter is adjusted, including: determining a reference control power according to a difference between a current DC voltage and an interval endpoint voltage of a voltage fluctuation interval; and adjusting the output power of the power converter according to the reference control power.

[0012] In one of the embodiments, the operation control condition includes a burst mode exit condition, which is determined by a first protection threshold and a second protection threshold, and the first protection threshold is less than the second protection threshold; judging whether a current DC voltage of a DC side circuit connected to a power converter satisfies the operation control condition, including: if the current DC voltage is less than the first protection threshold or greater than the second protection threshold, determining that the current DC voltage satisfies the burst mode exit condition; and controlling the operation process of the burst mode, including: stopping the burst mode.

[0013] In one of the embodiments, the operation control condition further includes a power adjustment condition, and the power adjustment condition is determined by a voltage fluctuation interval; the voltage fluctuation interval is between a first protection threshold and a second protection threshold.

[0014] In one of the embodiments, the method further includes: when the power converter operates in burst mode, at a preset operating time, determining a current capacitance value of a DC side capacitor in the power converter; determining whether the attenuation degree of the DC side capacitor reaches a target attenuation degree based on the current capacitance value of the DC side capacitor; if the target attenuation degree is reached, stopping the burst mode.

[0015] In one of the embodiments, determining whether the attenuation degree of the DC side capacitor reaches the target attenuation degree based on the current capacitance value of the DC side capacitor includes: determining the capacitance difference between the current capacitance value of the DC side capacitor and the initial capacitance value; wherein the initial capacitance value is the capacitance value when the DC side capacitor is not in use; if the capacitance difference is greater than a preset capacitance difference threshold, determining that the attenuation degree of the DC side capacitor reaches the target attenuation degree.

[0016] In one of the embodiments, the method further includes: when the power converter operates in the burst mode, determining the current output power of the DC side circuit; if the current output power of the DC side circuit is greater than a preset power threshold, stopping the burst mode.

[0017] In one of the embodiments, before the power converter operates in burst mode, the method also includes: determining that the current output power of the DC side circuit is not greater than a preset power threshold; determining whether an entry condition is met based on the current DC voltage of the DC side circuit; if the entry condition is met, controlling the power converter to operate in burst mode.

[0018] In one of the embodiments, determining whether the entry condition is met based on the current DC voltage of the DC side circuit includes: determining that the current DC voltage of the DC side circuit belongs to a first voltage interval within a preset duration, and then determining that the entry condition is met.

[0019] In a second aspect, the present application also provides an operation control device for a power converter. The device comprises:

[0020] A judgment module, used for judging whether a current DC voltage of a DC side circuit connected to the power converter satisfies an operation control condition when the power converter operates in a burst mode;

[0021] A control module is used to control the operation process of the burst mode if it is determined that the operation control condition is met; wherein controlling the operation process includes stopping the burst mode or adjusting the output power of the power converter.

[0022] In one embodiment, the operation control condition includes a power adjustment condition; the power adjustment condition is determined by the voltage fluctuation range; the judgment module is specifically used to:

[0023] If the current DC voltage does not belong to the voltage fluctuation range, it is determined that the current DC voltage meets the power adjustment condition;

[0024] The control module is specifically used to adjust the output power of the power converter.

[0025] In one of the embodiments, the device further includes an interval determination module, configured to:

[0026] Determine the average DC voltage of the DC side circuit during the historical operation stage; determine the voltage fluctuation range based on the average DC voltage and the preset fluctuation voltage.

[0027] In one of the embodiments, the control module is specifically used to: determine a reference control power according to a difference between a current DC voltage and an interval endpoint voltage of a voltage fluctuation interval; and adjust the output power of the power converter according to the reference control power.

[0028] In one of the embodiments, the operation control condition includes a burst mode exit condition, the burst mode exit condition is determined by a first protection threshold and a second protection threshold, the first protection threshold is less than the second protection threshold;

[0029] The judgment module is specifically used to: if the current DC voltage is less than the first protection threshold or greater than the second protection threshold, determine that the current DC voltage meets the burst mode exit condition;

[0030] The control module is specifically used to: stop the burst mode.

[0031] In one of the embodiments, the operation control condition further includes a power adjustment condition, and the power adjustment condition is determined by a voltage fluctuation interval; the voltage fluctuation interval is between a first protection threshold and a second protection threshold.

[0032] In one of the embodiments, the device also includes a capacitance detection module, which is used to: when the power converter operates in burst mode, determine the current capacitance value of the DC side capacitor in the power converter at a preset operating time; determine whether the attenuation degree of the DC side capacitor reaches the target attenuation degree based on the current capacitance value of the DC side capacitor; if the target attenuation degree is reached, stop the burst mode.

[0033] In one embodiment, the capacitance detection module is specifically used to: determine the capacitance difference between the current capacitance value and the initial capacitance value of the DC side capacitor; wherein the initial capacitance value is the capacitance value when the DC side capacitor is not in use; if the capacitance difference is greater than a preset capacitance difference threshold, it is determined that the attenuation degree of the DC side capacitor reaches the target attenuation degree.

[0034] In one of the embodiments, the device further includes a power detection module, which is used to: determine the current output power of the DC side circuit when the power converter operates in burst mode; if the current output power of the DC side circuit is greater than a preset power threshold, stop the burst mode.

[0035] In one of the embodiments, the device also includes a condition determination module, which is used to: before the power converter operates in burst mode, determine that the current output power of the DC side circuit is not greater than a preset power threshold; determine whether an entry condition is met based on the current DC voltage of the DC side circuit; if the entry condition is met, control the power converter to operate in burst mode.

[0036] In one of the embodiments, the condition determination module is specifically used to: determine that the current DC voltage of the DC side circuit belongs to the first voltage interval within a preset duration, and then determine that the entry condition is met.

[0037] In a third aspect, the present application further provides an inverter, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of any one of the methods described in the first aspect when executing the computer program.

[0038] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any one of the methods described in the first aspect above.

[0039] In a fifth aspect, the present application further provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, the steps of any one of the methods described in the first aspect are implemented.

[0040] The operation control method, device, inverter, medium and product of the power converter described above can determine whether the current DC voltage of the DC side circuit connected to the power converter meets the operation control conditions when the power converter is running in the burst mode; if it is determined that the operation control conditions are met, the operation process of the burst mode is controlled; wherein, the control of the operation process includes stopping the burst mode or adjusting the output power of the power converter. In this way, by setting the operation control conditions, the power converter can determine that the output of the current DC voltage has an impact on the system when it is determined that the operation control conditions are not met according to the current DC voltage of the DC side circuit. At this time, the process of the power converter running based on the burst mode is controlled in time to ensure the stable operation of the power converter and prevent the current DC voltage fluctuation and other conditions from affecting the efficiency of the power converter and causing the stability of the system where the power converter is located to decrease. wherein, the control of the operation process of the power converter includes stopping the burst mode or adjusting the output power of the power converter, which can not only ensure the stable operation of the power converter, but also improve the flexibility of the power converter control. Among them, it can be understood that if the burst mode is directly exited without meeting the operation control conditions, because the burst mode is exited when the working efficiency of the power converter is low, even if it is switched to other modes of operation, the working efficiency of the power converter will still be low within a certain period of time. The operation control method provided in the present application can not only realize the control method of stopping the burst mode, but also realize the control method of adjusting the output power of the power converter; based on this, the working efficiency of the power converter can be improved in time, not only avoiding the frequent switching of the working mode of the power converter, but also ensuring that the working efficiency of the power converter is restored to a higher value as soon as possible, effectively ensuring the stability of the operation of the power converter and the system in which it is located. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 is an application environment diagram of a power converter in one embodiment;

[0043] Figure 2 is a flow chart of an operation control method of a power converter in one embodiment;

[0044] Figure 3A schematic diagram of a flow chart for determining a voltage fluctuation range in one embodiment;

[0045] Figure 4 A schematic diagram of a process for adjusting the output power of a power converter in one embodiment;

[0046] Figure 5 A schematic diagram of the corresponding relationship between a DC voltage fluctuation process and a preset voltage threshold in an embodiment;

[0047] Figure 6 is a flow chart of determining whether to stop the burst mode according to the current capacitance value in one embodiment;

[0048] Figure 7 A schematic diagram of DC voltage comparison in different scenarios in an embodiment;

[0049] Figure 8 A schematic diagram of a flow chart for determining the attenuation degree of a DC side capacitor in one embodiment;

[0050] Fig. 9 A schematic diagram of a flow chart of controlling a power converter to enter a burst mode in one embodiment;

[0051] Fig.10 A schematic diagram of a correspondence between another DC voltage fluctuation process and a preset voltage threshold in an embodiment;

[0052] Fig.11 is a schematic flow chart of the operation process of a power converter in one embodiment;

[0053] Fig.12 FIG. 4 is a structural block diagram of an operation control device of a power converter in an embodiment. DETAILED DESCRIPTION

[0054] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. It should be understood that many specific details are set forth in the following description to facilitate a full understanding of the present application, but the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0055] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0056] It will be understood that “at least one” means one or more, and “plurality” means two or more.

[0057] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0058] Power converters are power conversion devices used to convert electrical energy from one form to another to achieve energy transmission and control under different power requirements. Power converters can be micro inverters, energy storage converters, etc. For example, a micro inverter can convert DC direct current into AC alternating current. The DC end (input) of the micro inverter is connected to a DC source (such as a photovoltaic module), and the AC end (output) of the power converter can be connected to an AC grid and an AC device.

[0059] Take the micro inverter that converts photovoltaic DC power into AC power as an example. Under low light conditions, the AC power output of the micro inverter is small, the efficiency of the micro inverter is reduced, and the current distortion rate is increased. If the micro inverter works in burst mode, it can reduce various problems caused by insufficient light intensity.

[0060] The burst mode is an intermittent operation mode that achieves the purpose of outputting a relatively high current when the power of the photovoltaic module is low by accumulating energy in the DC side capacitor, thereby improving the working efficiency of the micro inverter.

[0061] However, when operating in burst mode, the voltage of the DC side capacitor in the micro inverter will fluctuate greatly, resulting in a series of effects such as reduced MPPT (Maximum Power Point Tracking) efficiency of the micro inverter, which in turn affects the stability of the operation of the system in which the micro inverter is located.

[0062] In view of this, an embodiment of the present application provides an operation control method for a power converter, which can determine whether to exit the burst mode or adjust the output power of the power converter in a timely manner according to the current DC voltage of the DC side circuit during the operation of the power converter in the burst mode, so as to reduce the impact of DC voltage fluctuations caused by the burst mode on the operation stability of the system where the power converter is located based on these two control methods, and prevent the system from shutting down incorrectly and reducing power generation.

[0063] It should be noted that the execution subject of the embodiment of the present application may be a power converter. Optionally, the execution subject of the method may also be an operation control device of the power converter, and the operation control device of the power converter may be implemented as part or all of the power converter by software, hardware, or a combination of software and hardware; for example, the power converter includes a control component, and the operation control device of the power converter is deployed in the control component to execute the operation control method. Among them, the power converter can operate in burst mode and other modes to convert electrical energy from one form to another. In other words, the operation control method of the power converter provided in the embodiment of the present application can be used for various types of power converters that can work in burst mode. Optionally, the power converter may be an inverter (DC / AC) for converting direct current into alternating current, such as a micro inverter, which is not fully illustrated here. Optionally, in an exemplary application scenario, such as Figure 1 In the application environment schematic diagram shown in FIG. 1 , the first end of the power converter is connected to a DC side circuit, which is, for example, a circuit including a photovoltaic panel PV; the second end of the power converter is connected to a power grid; the power converter at least includes Figure 1 The DC side capacitor Cpv and the DC / AC module are shown. The power converter is used to convert the DC power generated by the photovoltaic panel into AC power. In the following method embodiments, the execution subject is the power converter for explanation.

[0064] In one embodiment, Figure 2 As shown, a method for controlling the operation of a power converter is provided, comprising the following steps:

[0065] Step 201 : when the power converter operates in the burst mode, it is determined whether the current DC voltage of the DC side circuit connected to the power converter meets the operation control condition.

[0066] Burst mode is an energy-saving working mode of the inverter. In this mode, the power converter does not operate continuously, but outputs power in the form of short pulses when needed. Exemplarily, an operating cycle includes a charging cycle and a discharging cycle; in an operating cycle, the power converter obtains energy transmitted by the DC side circuit during the charging cycle, and the energy is accumulated on the DC side capacitor; in the discharging cycle, the capacitor and the previous power converter or PV module provide energy to the subsequent circuit together, and output AC power. It can be seen that when working in burst mode, in multiple consecutive operating cycles, the power converter is in an operating mode in which charging and discharging are alternately performed.

[0067] The current DC voltage is the voltage of the DC power outputted by the DC side circuit to the power converter at the current moment. Since the power converter is connected to the DC side circuit, the current DC voltage of the DC side circuit can be detected. Figure 1 It can be known that the power converter includes a DC side capacitor, and the current DC voltage can be the current voltage across the DC side capacitor.

[0068] Since the power converter is affected by grid conditions and environmental conditions during operation in burst mode, the DC voltage of the DC side circuit will fluctuate as the charging cycle and discharging cycle of the power converter switch. Therefore, it is necessary to obtain the current DC voltage and determine whether the current DC voltage fluctuates too much based on the current DC voltage and operating control conditions, so as to determine whether the operation process of the power converter needs to be adjusted in time.

[0069] Among them, the power converter is deployed with an operation control condition. The operation control condition is determined according to at least one preset voltage threshold value related to the DC voltage of the DC side circuit. Therefore, it can be determined whether the operation control condition is met according to the current DC voltage. Optionally, some of the preset voltage threshold values ​​are fixed values ​​determined in advance by experiments; and another part of the preset voltage threshold values ​​are determined during the operation of the power converter.

[0070] Step 202: If it is determined that the operation control condition is met, the operation process of the burst mode is controlled.

[0071] Among them, if the operation control condition is met, it means that the current DC voltage fluctuation will cause the conversion performance of the power converter to be low, resulting in the working efficiency of the power converter being lower than the target working efficiency. At this time, by controlling the operation process of the burst mode, the fluctuation of the DC voltage is within the controllable voltage range.

[0072] Among them, the working efficiency of the power converter is the ratio of the output power to the input power, which represents the energy conversion efficiency of the power converter. Exemplarily, when the power converter is running based on the MPPT algorithm, it is necessary to adjust the working point according to the output characteristics of the PV component to achieve maximum power output. However, when the DC voltage fluctuates too much, it will make it difficult for the MPPT algorithm to accurately judge the actual working state of the PV component, resulting in algorithm failure or reduced efficiency. For example, when the PV component is stably operating at its maximum power point, the input power of the power converter is constant, while the output power of the power converter is transient, resulting in an instantaneous power imbalance problem between the input and output of the power converter. This imbalance is manifested on the output side of the PV component as a disturbance component in its output voltage. If the DC voltage fluctuates too much, this disturbance will be more obvious, thereby affecting the effect of the power decoupling link and reducing the efficiency of the MPPT.

[0073] Therefore, when the PV module is working stably at its maximum power point, it is necessary to ensure that the DC voltage fluctuation is within the controllable voltage range. At this time, the MPPT algorithm can accurately determine the actual working state of the PV module, thereby making accurate adjustments, thereby ensuring that the MPPT efficiency of the power converter is high.

[0074] Based on this, in the embodiment of the present application, the operation process of the power converter working in the burst mode can be precisely controlled in a timely manner based on the operation control conditions to ensure that the fluctuation of the DC voltage is within the controllable voltage range, thereby ensuring that the power converter has a high operating efficiency.

[0075] In the embodiment of the present application, controlling the operation process includes stopping the burst mode or adjusting the output power of the power converter.

[0076] That is, in an optional implementation method, when it is determined that the operating control conditions are met and it is determined that the fluctuation of the current DC voltage causes the working efficiency of the power converter to reach the first working efficiency, it is determined that it is not suitable to continue operating in the burst mode. Therefore, the power converter is controlled to stop operating in the burst mode to alleviate the fluctuation range of the current DC voltage, thereby timely reducing the risk of overvoltage and undervoltage faults in the DC side circuit and avoiding the reduction in power generation due to shutdown of the system where the power converter is located due to excessive voltage fluctuations.

[0077] Optionally, when the burst mode is stopped, that is, the power converter exits the burst mode, the power converter can be switched to operate in the normal mode. When operating in the normal mode, the power converter continuously performs the process of receiving direct current, converting the direct current into alternating current, and outputting the alternating current to the subsequent circuit. That is, in the normal mode, the power converter can continuously output alternating current.

[0078] In another optional implementation, when it is determined that the operation control condition is met, it is determined that the fluctuation degree of the current DC voltage causes the working efficiency of the power converter to be lower than the second working efficiency. The second working efficiency may be higher than the first working efficiency, that is, the burst mode may not be exited at this time, but the working efficiency of the power converter is still low. In order to make the fluctuation of the current DC voltage fall back to the controllable voltage range and ensure that the working efficiency of the power converter is high, the output power of the power converter may be adjusted at this time.

[0079] Exemplarily, the output power can be adjusted by reducing the current output power of the power converter. Thus, when the output power of the power converter is reduced, the energy absorbed by the power converter from the capacitor is reduced. Accordingly, the fluctuation range of the voltage on the DC side capacitor will become smaller, thereby falling back to a controllable voltage range.

[0080] Optionally, the degree of fluctuation of the current DC voltage when determining to perform the step of regulating the output power of the power converter is smaller than the degree of fluctuation of the current DC voltage when determining to perform the step of stopping the burst mode.

[0081] In the operation control method of the power converter, when the power converter is operated in the burst mode, it can be determined whether the current DC voltage of the DC side circuit connected to the power converter meets the operation control conditions; if it is determined that the operation control conditions are met, the operation process of the burst mode is controlled; wherein, the operation process is controlled including stopping the burst mode or adjusting the output power of the power converter. In this way, by setting the operation control conditions, the power converter can determine that the output of the current DC voltage has an impact on the system when it is determined that the operation control conditions are not met according to the current DC voltage of the DC side circuit. At this time, the process of the power converter running based on the burst mode is timely controlled to ensure the stable operation of the power converter and prevent the current DC voltage fluctuation and other conditions from affecting the efficiency of the power converter and causing the stability of the system where the power converter is located to decrease. wherein, the operation process of the power converter is controlled including stopping the burst mode or adjusting the output power of the power converter, which can not only ensure the stable operation of the power converter, but also improve the flexibility of the power converter control. Furthermore, it is understandable that if the burst mode is directly exited without satisfying the operating control conditions, because the burst mode is exited when the operating efficiency of the power converter is low, even if it is switched to other operating modes, the operating efficiency of the power converter will still be low within a certain period of time. The embodiment of the present application not only provides a control method for stopping the burst mode, but also provides a control method for adjusting the output power of the power converter. Based on this, the operating efficiency of the power converter can be improved in time, which not only avoids frequent switching of the operating mode of the power converter, but also ensures that the operating efficiency of the power converter is restored to a higher value as soon as possible.

[0082] In one embodiment, since stopping the burst mode and adjusting the output power of the power converter are two different control processes, different operating control conditions are set for different control processes, so that the power converter can accurately determine which control process to execute based on the operating control conditions satisfied by the current DC voltage at this moment, thereby ensuring the accurate operation of the power converter.

[0083] The process of adjusting the output power of the power converter and the process of determining the operating control conditions corresponding to the control process are described below.

[0084] In one embodiment, determining whether a current DC voltage of a DC side circuit connected to a power converter satisfies an operation control condition includes: if the current DC voltage does not belong to a voltage fluctuation interval, determining that the current DC voltage satisfies a power adjustment condition. Controlling the operation process of the burst mode includes: adjusting the output power of the power converter.

[0085] The operation control condition includes a power adjustment condition. The power adjustment condition is determined by the voltage fluctuation range. The power converter can determine whether the current DC voltage of the DC side circuit does not belong to the voltage fluctuation range. If it is determined that it does not belong to the voltage fluctuation range, it is determined that the power adjustment condition is met. If the power adjustment condition is met, the output power of the power converter is adjusted.

[0086] Optionally, the voltage fluctuation interval is determined during the operation of the power converter, for example, the voltage fluctuation interval may be determined during the operation of the power converter in a burst mode.

[0087] Optionally, the voltage fluctuation range is determined before determining the current DC voltage. In other words, the current DC voltage is the DC voltage of the DC side circuit at the current operating moment, and the voltage fluctuation range can be determined based on the DC voltage of the historical operating stage before the current operating moment.

[0088] In the embodiment of the present application, a dynamic output power adjustment mechanism is provided to determine in real time whether the current DC voltage meets the power adjustment conditions, and to dynamically adjust the output power of the power converter in a timely manner when the power adjustment conditions are met. In this way, under the condition that the DC side circuit provides different current DC voltages, the current DC voltage can be guaranteed to fall back to the controllable voltage range without exiting the burst mode, so that the power converter can continue to operate normally in the burst mode. In addition, whether the power adjustment conditions are met can be determined based on the relationship between the current DC voltage and the voltage fluctuation range, so that the power converter can improve the efficiency of determining whether output power adjustment is required with low complexity.

[0089] In one embodiment, Figure 3 A schematic diagram of a process for determining a voltage fluctuation range is shown. The voltage fluctuation range is determined in the following manner:

[0090] Step 301, determining the average DC voltage of the DC side circuit in the historical operation stage.

[0091] Optionally, the historical operation stage includes multiple historical operation cycles before the current operation moment.

[0092] Optionally, the power converter samples the DC voltage of the DC side circuit at different operating moments. After each DC voltage is obtained, the DC voltage is stored. It can be understood that the DC voltages obtained before the current operating moment are all DC voltages sampled in the historical operating stage.

[0093] In an optional implementation, the power converter obtains each historical DC voltage sampled in n historical operation cycles before the current operation moment, calculates the average value of each historical DC voltage, and obtains the average DC voltage of the historical operation stage.

[0094] In another optional implementation, the power converter obtains each historical DC voltage sampled in n historical operation cycles before the current operation moment. For each historical operation cycle, the historical average DC voltage corresponding to the historical operation cycle is calculated based on each historical DC voltage sampled in the historical operation cycle. Thus, the historical average DC voltage corresponding to each historical operation cycle can be obtained, and the average value of each historical average DC voltage is calculated to obtain the average DC voltage of the above-mentioned historical operation stage.

[0095] Optional, n≥1.

[0096] Optionally, the n historical operation cycles are the n historical operation cycles closest to the current operation moment in time.

[0097] Optionally, the number of historical DC voltages sampled in the historical operation cycle is the same. That is, the power converter samples the current DC voltage once at a fixed interval, stores the current DC voltage, and determines whether the operation control condition is met based on the current DC voltage, and then determines whether to control the operation process.

[0098] Step 302: Determine a voltage fluctuation range according to the average DC voltage and a preset fluctuation voltage.

[0099] A preset fluctuating voltage is pre-deployed in the power converter, and the preset fluctuating voltage can be determined in advance through experiments.

[0100] For example, an experimental power converter for experiment is set in an experimental environment, and the preset fluctuating voltage is determined according to the DC side capacitance of the experimental power converter, the output power and output voltage of the experimental power converter, the working mode of the experimental power converter, etc.

[0101] Exemplarily, the preset fluctuating voltage may be 5 V. It is understandable that different preset fluctuating voltages may be set in different power converters according to requirements, which are not fully illustrated here.

[0102] In an optional implementation, the voltage fluctuation interval is determined according to the average DC voltage and the preset fluctuation voltage, including: taking the difference between the average DC voltage and the preset fluctuation voltage as the left interval endpoint voltage; taking the sum of the average DC voltage and the preset fluctuation voltage as the right interval endpoint voltage. The left interval endpoint voltage and the right interval endpoint voltage constitute the voltage fluctuation interval. For example, the average DC voltage is U dc_avg , the preset fluctuating voltage is △U, then the voltage at the left end of the interval is U pro_min =U dc_avg -ΔU; voltage at the right end of the interval U pro_max =U dc_avg +ΔU. The voltage fluctuation interval is a closed interval: [U pro_min ,U pro_max ].

[0103] It is understandable that, in the process of continuous operation of the power converter, as time goes by, the historical operation stage is continuously updated, so the average DC voltage of the historical operation stage is continuously updated, and the voltage fluctuation range is also continuously updated.

[0104] In the embodiment of the present application, the voltage fluctuation range is determined dynamically in real time according to the average DC voltage in the historical operation stage to obtain the power adjustment condition. In this way, the judgment result of whether the current DC voltage meets the power adjustment condition is real-time, and the output power of the power converter is adjusted according to this judgment result, so that the adjustment of the output power of the power converter matches the operation of the DC side circuit, so that the fluctuation of the DC voltage quickly falls back to the controllable voltage range, and the accuracy and precision of the entire adjustment process are guaranteed. In addition, since the voltage fluctuation range can be determined according to the average DC voltage and the preset fluctuation voltage in the historical operation stage, this method can accurately determine the voltage fluctuation range with low complexity, thereby ensuring the efficiency of the voltage fluctuation range update.

[0105] In one embodiment, Figure 4 A schematic diagram of a process for adjusting the output power of a power converter is shown. The output power of the power converter is adjusted, including:

[0106] Step 401 : determining a reference control power according to a difference between a current DC voltage and an interval endpoint voltage of a voltage fluctuation interval.

[0107] Here, the interval endpoint voltage includes the left interval endpoint voltage and the right interval endpoint voltage of the above-mentioned voltage fluctuation interval.

[0108] In an optional implementation, if the current DC voltage does not belong to the voltage fluctuation interval and is less than the left interval endpoint voltage, the reference control power is determined based on the difference between the left interval endpoint voltage of the voltage fluctuation interval and the current DC voltage.

[0109] In another optional implementation, if the current DC voltage does not belong to the voltage fluctuation interval and the current DC voltage is greater than the right interval endpoint voltage, the reference control power is determined according to the difference between the current DC voltage and the right interval endpoint voltage of the voltage fluctuation interval.

[0110] Optionally, a power relationship correspondence table is pre-deployed in the power converter; the power relationship correspondence table includes correspondences between multiple sets of voltage difference values ​​and candidate control powers. After determining the difference between the current DC voltage and the voltage at the end point of the voltage fluctuation interval, the power relationship correspondence table is queried according to the difference, and the candidate control power corresponding to the difference is used as the reference control power.

[0111] Step 402: adjust the output power of the power converter according to the reference control power.

[0112] Exemplarily, the determined reference control power is smaller than the current output power of the power converter, and the output power of the power converter may be adjusted to the value of the reference control power.

[0113] In the embodiment of the present application, the reference control power currently required is determined according to the current DC voltage and the voltage fluctuation range, and the current output power of the power converter is adaptively adjusted based on the reference control power to ensure that the current output power regulation of the power converter matches the degree of DC voltage fluctuation and the accuracy of the adjustment. Thus, by taking the protective measure of adjusting the output power, the power converter continues to operate stably in the burst mode, and transmits power to the power grid in an intermittent manner to maintain a high MPPT efficiency and reduce the current distortion rate.

[0114] The control process of stopping the burst mode and the judgment process of the operation control conditions corresponding to the control process are described below.

[0115] In one embodiment, determining whether a current DC voltage of a DC side circuit connected to a power converter satisfies an operation control condition includes: if the current DC voltage is less than a first protection threshold or greater than a second protection threshold, determining that the current DC voltage satisfies a burst mode exit condition. Controlling the operation process of the burst mode includes: stopping the burst mode.

[0116] The operation control condition further includes a burst mode exit condition, which is determined by a first protection threshold and a second protection threshold, and the first protection threshold is smaller than the second protection threshold.

[0117] Optionally, the first protection threshold and the second protection threshold are fixed values ​​determined in advance by experiments. They can be pre-deployed in the power converter. Exemplarily, in an experimental environment, multiple scenarios are provided in which the DC voltage detected by the experimental power converter is too large or too small, so that the experimental power converter needs to exit the burst mode. The first protection threshold and the second protection threshold are determined according to the DC voltage of the DC side circuit detected when exiting the burst mode in these scenarios.

[0118] It can be understood that if the current DC voltage is less than the first protection threshold, it indicates that the current DC voltage is too low, and if the current DC voltage is greater than the second protection threshold, it indicates that the current DC voltage is too high. If the current DC voltage is too low or too high, there is a risk of causing the power converter to shut down. Therefore, it is necessary to exit the burst mode in time.

[0119] In the embodiment of the present application, when the current DC voltage is less than the first protection threshold or greater than the second protection threshold, the burst mode is exited in time and the normal mode is switched. In the normal mode, the power converter needs to continuously output AC power, and the DC side capacitor will not continuously accumulate energy like the burst mode, so the energy accumulated by the DC side capacitor will be lower than that in the burst mode. When the energy is continuously converted, at this time, the energy accumulated by the DC side capacitor is reduced, the voltage on the DC side capacitor is reduced, and the current DC voltage is reduced, even if the risk of power converter failure shutdown caused by overvoltage and undervoltage is reduced, the power converter is prevented from shutting down. In this way, the power converter switches from the burst mode to the normal mode, and can operate normally and output AC power throughout the process, and will not reduce the power generation of the system where the power converter is located.

[0120] In one embodiment, as mentioned above, the operation control condition also includes a power adjustment condition, and the power adjustment condition is determined by a voltage fluctuation interval. Furthermore, the voltage fluctuation interval is between a first protection threshold and a second protection threshold.

[0121] Optional, such as Figure 5 A schematic diagram showing the correspondence between a DC voltage fluctuation process and a preset voltage threshold is shown. Here, the first protection threshold U exit_minThe voltage U at the left end of the voltage fluctuation interval is smaller than pro_min ; The second protection threshold U exit_max The voltage U at the right end of the voltage fluctuation interval is greater than pro_max .

[0122] It can be understood that if the current DC voltage is within the voltage fluctuation range, the power converter operates normally in the burst mode. Figure 5 As shown, the first protection threshold U exit_min and the left interval endpoint voltage U pro_min The voltage protection range is formed between the second protection threshold U exit_max and the voltage at the right end of the interval U pro_max Another voltage protection range is formed between the first protection threshold U exit_min and the second protection threshold U exit_max If the current DC voltage is within the voltage protection range, the output power of the power converter is adjusted to achieve undervoltage protection, and if the current DC voltage is within the exit range, the burst mode is stopped to achieve overvoltage exit.

[0123] Optionally, the values ​​of the first protection threshold and the left interval endpoint voltage may be negative values, depending on the operating conditions of the power converter, and are not specifically limited here.

[0124] Since the voltage fluctuation range is between the first protection threshold and the second protection threshold, when it is determined that the power adjustment condition is not met, that is, the current DC voltage is within the voltage fluctuation range, then the current DC voltage must also be between the first protection threshold and the second protection threshold, and does not meet the burst mode exit condition.

[0125] Therefore, optionally, it is possible to first determine whether the current DC voltage meets the power adjustment condition according to the voltage fluctuation range, and if it is determined that the power adjustment condition is met, determine whether the current DC voltage meets the burst mode exit condition. If it is determined that the current DC voltage does not meet the power adjustment condition, that is, the current DC voltage is within the voltage fluctuation range, the process of determining whether the current DC voltage meets the burst mode exit condition may not be performed, thereby reducing the computing power of the power converter.

[0126] As mentioned above, the power converter includes DC side capacitors, which will continue to age or become damaged during use. Since the fluctuation degree of the DC voltage is inversely proportional to the capacitance value of the DC side capacitor, if the DC side capacitor is aged or damaged, it will also cause excessive DC voltage fluctuations when the power converter operates in burst mode.

[0127] Therefore, the embodiment of the present application can also determine whether it is necessary to exit the burst mode in time according to the DC side capacitor to ensure the normal operation of the power converter. Optionally, the DC side capacitor in the power converter is a capacitor group composed of multiple capacitors, and the capacitance value of the DC side capacitor is the equivalent capacitance value of the multiple capacitors.

[0128] In one embodiment, Figure 6 A schematic diagram of a process for determining whether to stop the burst mode according to the current capacitance value is shown. The method further includes:

[0129] Step 601 : when the power converter operates in a burst mode, at a preset operating time, determining a current capacitance value of a DC link capacitor in the power converter.

[0130] Optionally, the preset operation time is the end time of the first operation cycle when the power converter is operated in the burst mode. That is, at the end of the first operation cycle, the current capacitance value is determined.

[0131] Optionally, the preset running time may also be the end time of any running cycle.

[0132] The maximum DC voltage U of the DC side circuit detected by the power converter in the first operation cycle can be used as the input voltage. H , minimum DC voltage U L , the total duration of the operation cycle T, the DC current I of the DC side circuit at the preset operation time pv and the DC voltage U at the preset operating time PV Determine the current capacitance value of the DC link capacitor.

[0133] Exemplarily, according to the circuit structure of the power converter: .

[0134] Then, the estimated value of the DC link capacitance is for: .

[0135] Therefore, the current capacitance value can be estimated according to the above formula: .

[0136] Step 602: Determine whether the attenuation degree of the DC link capacitor reaches the target attenuation degree according to the current capacitance value of the DC link capacitor.

[0137] As the DC side capacitor is continuously used, the capacitance value decreases continuously, that is, the DC side capacitor is continuously attenuated, so it can be determined whether the attenuation reaches the target attenuation level according to the current capacitance value. Figure 7A schematic diagram of DC voltage comparison in different scenarios is shown. It can be seen that when the DC side capacitor in the power converter is a normal capacitor that has not reached the target attenuation level, the DC voltage fluctuation amplitude of the DC side circuit is small, and when the DC side capacitor in the power converter is an aged capacitor that has reached the target attenuation level, the DC voltage fluctuation amplitude of the DC side circuit is large.

[0138] Optionally, the target attenuation degree is represented by a preset capacitance value or a preset capacitance value range.

[0139] Step 603: If the target attenuation level is reached, the burst mode is stopped.

[0140] If the target attenuation level is reached, it indicates that the current capacitance value has attenuated excessively, which will have a significant impact on the DC voltage of the DC side circuit. Therefore, the burst mode needs to be stopped to avoid these impacts in time.

[0141] In the embodiment of the present application, the current capacitance value of the DC side capacitor is determined to determine whether the DC side capacitor is attenuated too much, and the burst mode is exited in time. In this way, it is possible to avoid excessive fluctuations in the DC voltage due to a reduction in the capacitance, thereby causing overvoltage, undervoltage, and the like, and also reduce the impact on the MPPT tracking efficiency of the power converter, thereby ensuring the working performance of the power converter. It can be understood that on the basis of setting the operating control conditions, the attenuation degree of the DC side capacitor is combined to determine whether to stop the burst mode, so that the control process of the power converter is more comprehensive, and the stability of the power converter in the burst mode is also ensured.

[0142] In one embodiment, Figure 8 A schematic diagram of a process for determining the attenuation degree of a DC side capacitor is shown. According to the current capacitance value of the DC side capacitor, determining whether the attenuation degree of the DC side capacitor reaches the target attenuation degree includes:

[0143] Step 801, determining a capacitance difference between a current capacitance value and an initial capacitance value of a DC link capacitor.

[0144] The initial capacitance value is the capacitance value when the DC side capacitor is not in use. The power converter is pre-deployed with the initial capacitance value.

[0145] Step 802: If the capacitance difference is greater than a preset capacitance difference threshold, it is determined that the attenuation degree of the DC link capacitance reaches a target attenuation degree.

[0146] A preset capacitance difference threshold is pre-deployed in the power converter. The calculated capacitance difference is compared with the preset capacitance difference threshold. If it is greater than the preset capacitance difference threshold, it means that the DC side capacitance is excessively attenuated and reaches the target attenuation level.

[0147] In the embodiment of the present application, based on the initial capacitance value and the preset capacitance difference threshold, the power converter can accurately and efficiently determine whether the DC side capacitance reaches the target attenuation level, and the flexibility of the power converter operation control is improved.

[0148] In one embodiment, the method further includes: when the power converter operates in the burst mode, determining the current output power of the DC side circuit; if the current output power of the DC side circuit is greater than a preset power threshold, stopping the burst mode.

[0149] The current output power of the DC side circuit may refer to the output power of the DC side circuit at the current operating moment.

[0150] The current output power of the DC side circuit is compared with the preset power threshold. When it is determined that the current output power of the DC side circuit is greater than the preset power threshold, it means that the current power is large enough and there is no need to operate in burst mode to ensure the output power. Therefore, it is necessary to exit the burst mode. At this time, the power converter can be converted to work in normal mode to ensure normal power generation.

[0151] Optionally, if it is determined that the current output power of the DC side circuit is greater than the preset power threshold, the current output power is continuously detected to see if it is greater than the preset power threshold. If the current output power of the DC side circuit is greater than the preset power threshold within the first continuous duration, the burst mode is stopped. It is understandable that at a certain moment, the DC voltage suddenly changes greatly, and at this time the output power of the DC side circuit is greater than the preset power threshold. If the DC voltage drops at the next moment, the output power also drops to less than the preset power threshold. Considering this situation, in an embodiment of the present application, when it is determined that the current output power of the DC side circuit is greater than the preset power threshold within the first continuous duration, the burst mode is stopped, which can avoid the occurrence of an erroneous switching of the operating mode of the power converter due to the instantaneous increase in the output power of the DC side circuit, and ensure the stability of the operating mode of the switching power converter.

[0152] The control process of the power converter in the burst mode is described above. In addition, in order to ensure the stable operation of the power converter in the burst mode and avoid switching back and forth between the burst mode and the normal mode, an entry condition is also set to ensure that the power converter is controlled to enter the burst mode under a stable environment.

[0153] In one embodiment, Fig. 9 A schematic diagram of a process for controlling a power converter to enter a burst mode is shown. The method further includes:

[0154] Step 901: determine whether the current output power of the DC side circuit is not greater than a preset power threshold.

[0155] Before the power converter operates in the burst mode, during the operation of the power converter, the current output power of the DC side circuit is determined and compared with a preset power threshold.

[0156] Optionally, before operating in the burst mode, the power converter may operate in the normal mode, that is, it is determined that the current output power of the DC side circuit is not greater than a preset power threshold when the power converter operates in the normal mode.

[0157] If it is determined that the current output power of the DC side circuit is not greater than the preset power threshold, then prepare to enter the burst mode.

[0158] Step 902: Determine whether an entry condition is met according to the current DC voltage of the DC side circuit.

[0159] An entry condition is pre-deployed in the power converter. Optionally, the entry condition is determined by a predetermined first voltage interval.

[0160] Exemplarily, if the current DC voltage of the DC side circuit belongs to the first voltage interval, it is determined that the entry condition is met.

[0161] Step 903: If the entry condition is met, the power converter is controlled to operate in the burst mode.

[0162] That is, when it is determined that the current output power of the DC side circuit is not greater than the preset power threshold, the burst mode is prepared to be entered. At this time, if it is determined that the entry condition is still met, the burst mode is formally entered, and the power converter is controlled to operate in the burst mode.

[0163] It can be understood that if the power converter is controlled to operate in burst mode only when it is determined that the current output power of the DC side circuit is not greater than the preset power threshold, then, combined with the above processing of stopping the burst mode when the current output power of the DC side circuit is greater than the preset power threshold, it can be seen that if the current output power of the DC side circuit fluctuates above and below the preset power threshold, the power converter will be continuously switched between entering and exiting the burst mode, resulting in unstable operation of the power converter, which may cause failure of the power converter, resulting in reduced power generation, and affecting the overall stable operation of the system in which the power converter is located.

[0164] In the embodiment of the present application, before entering the burst mode, it is first determined whether the current output power of the DC side circuit is lower than the preset power threshold, and whether the current DC voltage is within the first voltage interval. Based on this, whether to start the operation burst mode is determined based on the output power and the DC voltage. Compared with determining whether to enter the burst mode only based on the output power, it can more accurately and effectively control the power converter to enter the burst mode under appropriate circumstances, avoid frequent switching of the power converter operation mode, and improve the stability of the power converter operation.

[0165] In one embodiment, determining whether the entry condition is met according to the current DC voltage of the DC side circuit includes: determining that the current DC voltage of the DC side circuit belongs to a first voltage interval within a preset duration, and then determining that the entry condition is met.

[0166] That is, when it is determined that the current output power of the DC side circuit is not greater than the preset power threshold, and it is determined that the current DC voltage of the DC side circuit is in the first voltage interval, the current DC voltage of the DC side circuit is continuously detected within the preset duration to see whether it continues to belong to the first voltage interval. If so, it is determined that the entry condition is met.

[0167] Optionally, within a preset duration, the current output power of the DC side circuit is also not greater than a preset power threshold.

[0168] Optionally, before the power converter operates in the burst mode, it may determine whether the current output power of the DC side circuit is not greater than a preset power threshold after each fixed time interval.

[0169] Optionally, the first voltage interval is within the voltage fluctuation interval. Fig.10 As shown, the voltage U at the left end of the voltage fluctuation interval pro_min The left interval endpoint voltage U is smaller than the first voltage interval in_min ; The voltage U at the right end of the voltage fluctuation interval pro_max Greater than the right interval endpoint voltage U of the first voltage interval in_max .

[0170] It can be seen that if the DC voltage belongs to the first voltage interval for the preset duration, it indicates that the current DC voltage is relatively stable. Entering the burst mode when the current DC voltage and the current output power of the DC side circuit are relatively stable can avoid the frequent switching of the operating mode of the power converter due to instantaneous DC voltage fluctuations or output power fluctuations, thereby ensuring the effectiveness of the power converter switching to the burst mode. In this way, while improving the efficiency of the power converter operating in the burst mode, the DC voltage fluctuation is within a controllable range. By setting the first voltage interval, it is possible to prevent problems such as overvoltage or undervoltage from occurring as soon as the burst mode is entered, thereby ensuring stable operation.

[0171] For ease of understanding, the following describes the operation control method of the power converter using a complete embodiment. Fig.11 , which shows a flow chart of the operation process of a power converter.

[0172] When the power converter is running in the normal mode, it is determined whether the current output power of the DC side circuit is not greater than the preset power threshold. If it is determined that the current output power of the DC side circuit is not greater than the preset power threshold, it is determined whether the current DC voltage of the DC side circuit belongs to the first voltage interval [U in_min , U in_max ], if so, it is determined that the entry condition is met, and the power converter is controlled to operate in the burst mode. When the power converter is operating in the burst mode, it is determined whether the current DC voltage of the DC side circuit connected to the power converter does not belong to the [U exit_min , U exit_max ], if so, exit the burst mode. And at a preset operating time, determine the capacitance difference between the current capacitance value and the initial capacitance value of the DC side capacitor in the power converter, if the capacitance difference is greater than a preset capacitance difference threshold, exit the burst mode. And, determine whether the current output power of the DC side circuit is greater than a preset power threshold, if so, exit the burst mode. And, determine whether the current DC voltage does not belong to the voltage fluctuation interval [U pro_min , U pro_max ], the output power of the power converter is adjusted. The reference control power is determined according to the difference between the current DC voltage and the voltage at the end point of the voltage fluctuation interval; and the output power of the power converter is adjusted according to the reference control power.

[0173] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0174] Based on the same inventive concept, the embodiment of the present application also provides a power converter operation control device for implementing the above-mentioned power converter operation control method. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above-mentioned method, so the specific limitations in the embodiments of the operation control device of one or more power converters provided below can refer to the limitations of the power converter operation control method above, and will not be repeated here.

[0175] In one embodiment, Fig.12 As shown, a power converter operation control device is provided, and the power converter operation control device 1200 includes: a judgment module 1201 and a control module 1202, wherein:

[0176] A judgment module 1201 is used to judge whether a current DC voltage of a DC side circuit connected to the power converter meets an operation control condition when the power converter operates in a burst mode;

[0177] The control module 1202 is used to control the operation process of the burst mode if it is determined that the operation control condition is met; wherein controlling the operation process includes stopping the burst mode or adjusting the output power of the power converter.

[0178] In one embodiment, the operation control condition includes a power adjustment condition; the power adjustment condition is determined by the voltage fluctuation range; the judgment module 1201 is specifically used to:

[0179] If the current DC voltage does not belong to the voltage fluctuation range, it is determined that the current DC voltage meets the power adjustment condition;

[0180] The control module 1202 is specifically used to adjust the output power of the power converter.

[0181] In one embodiment, the apparatus further includes an interval determination module, configured to:

[0182] Determine the average DC voltage of the DC side circuit during the historical operation stage; determine the voltage fluctuation range based on the average DC voltage and the preset fluctuation voltage.

[0183] In one embodiment, the control module 1202 is specifically used to: determine a reference control power according to a difference between a current DC voltage and an interval endpoint voltage of a voltage fluctuation interval; and adjust the output power of the power converter according to the reference control power.

[0184] In one embodiment, the operation control condition includes a burst mode exit condition, the burst mode exit condition is determined by a first protection threshold and a second protection threshold, the first protection threshold is less than the second protection threshold;

[0185] The judgment module 1201 is specifically used to: if the current DC voltage is less than the first protection threshold or greater than the second protection threshold, determine that the current DC voltage meets the burst mode exit condition;

[0186] The control module 1202 is specifically used to stop the burst mode.

[0187] In one embodiment, the operation control condition further includes a power adjustment condition, and the power adjustment condition is determined by a voltage fluctuation interval; the voltage fluctuation interval is between a first protection threshold and a second protection threshold.

[0188] In one embodiment, the device also includes a capacitance detection module, which is used to: when the power converter operates in burst mode, determine the current capacitance value of the DC side capacitor in the power converter at a preset operating time; determine whether the attenuation degree of the DC side capacitor reaches the target attenuation degree based on the current capacitance value of the DC side capacitor; if the target attenuation degree is reached, stop the burst mode.

[0189] In one embodiment, the capacitance detection module is specifically used to: determine the capacitance difference between the current capacitance value and the initial capacitance value of the DC side capacitor; wherein the initial capacitance value is the capacitance value when the DC side capacitor is not in use; if the capacitance difference is greater than a preset capacitance difference threshold, it is determined that the attenuation degree of the DC side capacitor reaches the target attenuation degree.

[0190] In one embodiment, the device further includes a power detection module for: determining the current output power of the DC side circuit when the power converter operates in burst mode; and stopping the burst mode if the current output power of the DC side circuit is greater than a preset power threshold.

[0191] In one embodiment, the device also includes a condition determination module, which is used to: before the power converter operates in burst mode, determine that the current output power of the DC side circuit is not greater than a preset power threshold; determine whether the entry condition is met based on the current DC voltage of the DC side circuit; if the entry condition is met, control the power converter to operate in burst mode.

[0192] In one embodiment, the condition determination module is specifically used to: determine that the current DC voltage of the DC side circuit belongs to the first voltage interval within a preset duration, and then determine that the entry condition is met.

[0193] Each module in the operation control device of the power converter can be implemented in whole or in part by software, hardware and a combination thereof. Each module can be embedded in or independent of the processor in the power converter in the form of hardware, or can be stored in the memory in the power converter in the form of software, so that the processor can call and execute the operations corresponding to each module.

[0194] In one embodiment, an inverter is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the following steps are implemented:

[0195] When the power converter operates in burst mode, it is determined whether the current DC voltage of the DC side circuit connected to the power converter meets the operation control conditions; if it is determined that the operation control conditions are met, the operation process of the burst mode is controlled; wherein, controlling the operation process includes stopping the burst mode or adjusting the output power of the power converter.

[0196] In one embodiment, the operating control conditions include power adjustment conditions; the power adjustment conditions are determined by the voltage fluctuation range; the processor also implements the following steps when executing the computer program: if the current DC voltage does not belong to the voltage fluctuation range, it is determined that the current DC voltage meets the power adjustment conditions; and the output power of the power converter is adjusted.

[0197] In one embodiment, the processor further implements the following steps when executing the computer program:

[0198] Determine the average DC voltage of the DC side circuit during the historical operation stage; determine the voltage fluctuation range based on the average DC voltage and the preset fluctuation voltage.

[0199] In one embodiment, the processor further implements the following steps when executing the computer program:

[0200] The reference control power is determined according to the difference between the current DC voltage and the voltage at the end point of the voltage fluctuation interval; and the output power of the power converter is adjusted according to the reference control power.

[0201] In one embodiment, the operation control condition includes a burst mode exit condition, the burst mode exit condition is determined by a first protection threshold and a second protection threshold, and the first protection threshold is less than the second protection threshold; when the processor executes the computer program, the following steps are further implemented:

[0202] If the current DC voltage is less than the first protection threshold or greater than the second protection threshold, it is determined that the current DC voltage meets the burst mode exit condition; and the burst mode is stopped.

[0203] In one embodiment, the operation control condition further includes a power adjustment condition, and the power adjustment condition is determined by a voltage fluctuation interval; the voltage fluctuation interval is between a first protection threshold and a second protection threshold.

[0204] In one embodiment, the processor further implements the following steps when executing the computer program:

[0205] When the power converter operates in the burst mode, at a preset operating time, the current capacitance value of the DC side capacitor in the power converter is determined; based on the current capacitance value of the DC side capacitor, it is determined whether the attenuation degree of the DC side capacitor reaches the target attenuation degree; if the target attenuation degree is reached, the burst mode is stopped.

[0206] In one embodiment, the processor further implements the following steps when executing the computer program:

[0207] Determine a capacitance difference between a current capacitance value and an initial capacitance value of a DC side capacitor, wherein the initial capacitance value is a capacitance value when the DC side capacitor is not in use; if the capacitance difference is greater than a preset capacitance difference threshold, determine that the attenuation degree of the DC side capacitor reaches a target attenuation degree.

[0208] In one embodiment, the processor further implements the following steps when executing the computer program:

[0209] When the power converter operates in the burst mode, the current output power of the DC side circuit is determined; if the current output power of the DC side circuit is greater than a preset power threshold, the burst mode is stopped.

[0210] In one embodiment, the processor further implements the following steps when executing the computer program:

[0211] Determine that the current output power of the DC side circuit is not greater than a preset power threshold; determine whether an entry condition is met based on the current DC voltage of the DC side circuit; if the entry condition is met, control the power converter to operate in a burst mode.

[0212] In one embodiment, the processor further implements the following steps when executing the computer program:

[0213] If it is determined that the current DC voltage of the DC side circuit belongs to the first voltage interval within the preset duration, it is determined that the entry condition is met.

[0214] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0215] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0216] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0217] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0218] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for controlling the operation of a power converter, characterized in that: The method comprises: When the power converter is operating in the burst mode, determining whether a current DC voltage of a DC side circuit connected to the power converter satisfies an operation control condition; If it is determined that the operation control condition is met, the operation process of the burst mode is controlled; wherein controlling the operation process includes stopping the burst mode or adjusting the output power of the power converter.

2. The method according to claim 1, characterized in that The operation control condition includes a power adjustment condition; the power adjustment condition is determined by the voltage fluctuation range; Determining whether a current DC voltage of a DC side circuit connected to the power converter satisfies an operation control condition, comprising: if the current DC voltage does not belong to the voltage fluctuation range, determining that the current DC voltage satisfies the power adjustment condition; The controlling of the operation process of the burst mode includes: adjusting the output power of the power converter.

3. The method according to claim 2, characterized in that The voltage fluctuation range is determined by: Determining an average DC voltage of the DC side circuit during a historical operation stage; The voltage fluctuation range is determined according to the average DC voltage and the preset fluctuation voltage.

4. The method according to claim 2, characterized in that: The step of adjusting the output power of the power converter comprises: Determining a reference control power according to a difference between the current DC voltage and an interval endpoint voltage of the voltage fluctuation interval; The output power of the power converter is adjusted according to the reference control power.

5. The method according to claim 1, characterized in that The operation control condition includes a burst mode exit condition, the burst mode exit condition is determined by a first protection threshold and a second protection threshold, the first protection threshold is less than the second protection threshold; Determining whether a current DC voltage of a DC side circuit connected to the power converter satisfies an operation control condition, comprising: if the current DC voltage is less than the first protection threshold or greater than the second protection threshold, determining that the current DC voltage satisfies the burst mode exit condition; The controlling the operation process of the burst mode includes: stopping the burst mode.

6. The method according to claim 5, characterized in that The operation control condition also includes a power adjustment condition, and the power adjustment condition is determined by the voltage fluctuation range; The voltage fluctuation interval is between the first protection threshold and the second protection threshold.

7. The method according to any one of claims 1 to 6, characterized in that: The method further comprises: When the power converter is operated in the burst mode, at a preset operating time, determining a current capacitance value of a DC link capacitor in the power converter; Determining whether the attenuation degree of the DC link capacitor reaches a target attenuation degree according to the current capacitance value of the DC link capacitor; If the target attenuation level is reached, the burst mode is stopped.

8. The method according to claim 7, characterized in that The determining, according to the current capacitance value of the DC link capacitor, whether the attenuation degree of the DC link capacitor reaches the target attenuation degree includes: Determine a capacitance difference between a current capacitance value and an initial capacitance value of the DC link capacitor; wherein the initial capacitance value is a capacitance value when the DC link capacitor is not in use; If the capacitance difference is greater than a preset capacitance difference threshold, it is determined that the attenuation degree of the DC link capacitance reaches the target attenuation degree.

9. The method according to any one of claims 1 to 6, characterized in that: The method further comprises: When the power converter operates in a burst mode, determining a current output power of the DC side circuit; If the current output power of the DC side circuit is greater than a preset power threshold, the burst mode is stopped.

10. The method according to any one of claims 1 to 6, characterized in that: Before the power converter operates in the burst mode, the method further comprises: Determining that the current output power of the DC side circuit is not greater than a preset power threshold; Determining whether an entry condition is met according to a current DC voltage of the DC side circuit; If the entry condition is met, the power converter is controlled to operate in the burst mode.

11. The method according to claim 10, characterized in that The determining whether an entry condition is met according to the current DC voltage of the DC side circuit includes: If it is determined that the current DC voltage of the DC side circuit belongs to the first voltage interval within a preset duration, it is determined that the entry condition is met.

12. An operation control device for a power converter, characterized in that: The device comprises: A judgment module, used for judging whether a current DC voltage of a DC side circuit connected to the power converter satisfies an operation control condition when the power converter operates in a burst mode; A control module is used to control the operation process of the burst mode if it is determined that the operation control condition is met; wherein controlling the operation process includes stopping the burst mode or adjusting the output power of the power converter.

13. An inverter, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 11 are implemented.

14. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 11 are implemented.

15. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 11 are implemented.

Images