Power system, power converter and control method of power converter

Abstract

The invention discloses a power system, a power converter and a control method of the power converter, and belongs to the technical field of power systems. The input ends of the direct-current conversion circuits are connected with at least one direct-current string, the output ends of the direct-current conversion circuits are connected into a direct-current bus in parallel, the input ends of the inverter circuits are connected with the direct-current bus, and the direct-current string comprises at least one power converter. DC output ends of the power converters are connected in series with an input end of the DC conversion circuit; the power converter is used for acquiring the current output power corresponding to the current output current under the condition that the current output current is greater than or equal to the limiting current threshold value, and controlling the input voltage of the power converter based on the current output power and the limiting current range of the power converter; and the inverter circuit is used for performing maximum power point tracking under the condition that the output voltage of the direct-current string is smaller than the maximum power point voltage value and the sum of the output power of the direct-current string is smaller than the output power threshold value.

Description

Technical Field

[0001] The present application belongs to the technical field of power systems, and in particular, relates to a power system, a power converter, and a control method for the power converter. Background Art

[0002] In power systems, multiple optimizers are mostly connected in series to work with inverters to achieve maximum power point tracking control of multiple power sources. For a single optimizer, it is necessary to limit the output current when overcurrent occurs to keep the current within the normal range.

[0003] The current limiting method of the optimizer currently used is voltage and current dual loop control, with the voltage loop serving as the given value of the current loop. If the output current needs to be limited, the output upper limit of the voltage loop is limited. This method will cause large fluctuations in the output voltage of the optimizer, which may cause a sudden drop, resulting in poor operational stability of the power system. Summary of the invention

[0004] 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 power system, a power converter and a control method of the power converter, which can ensure that the series-connected multiple power converters can output power continuously and stably as a whole, and ensure the stable operation of the entire power system.

[0005] In a first aspect, the present application provides a power system, comprising:

[0006] Inverter and at least one DC string;

[0007] The inverter includes at least one DC conversion circuit, a DC bus and an inverter circuit, the DC conversion circuit input end is connected to at least one DC string, the output ends of each DC conversion circuit are connected to the DC bus in parallel, the inverter circuit input end is connected to the DC bus, the DC string includes at least one power converter, the power converter includes a DC input end and a DC output end, the DC input end is used to connect to a DC power source, and the DC output end of each power converter in the DC string is connected in series to the input end of the DC conversion circuit;

[0008] The power converter is used to obtain the current output power corresponding to the current output current when the current output current is greater than or equal to the current limiting threshold, and control the input voltage of the power converter itself based on the current output power and the current limiting range of the power converter;

[0009] The inverter circuit is used to perform maximum power point tracking when the output voltage of the DC string is less than the maximum power point voltage value and the sum of the output powers of the DC strings is less than the output power threshold.

[0010] According to the power system of the present application, the two ends of multiple power converters connected in series are respectively connected to the two ends of the inverter, and each power converter is connected to a DC power supply. When the power converter detects that its own output current is greater than or equal to the limiting current threshold, it enters the current limiting state, and controls its own input voltage through the current output power and the limiting current range. The inverter can adjust the output power of multiple power converters, and the power converter performs derating control based on the current output power corresponding to the limiting current threshold as the reference parameter. The control of the input voltage is stable and controllable, the inverter can cooperate with the power converter to perform power adjustment, and the system operation has high stability.

[0011] According to one embodiment of the present application, the limiting current range includes a starting boundary value and an ending boundary value. When the current output current is greater than or equal to the limiting current threshold, the power converter is used to determine the ending output power corresponding to the ending boundary value based on the current output power, and control its own input voltage based on the starting boundary value, the ending boundary value, the current output power and the ending output power.

[0012] According to one embodiment of the present application, the starting boundary value is equal to the limiting current threshold.

[0013] According to one embodiment of the present application, the power converter is used to determine a first function point with the starting boundary value and the current output power, determine a second function point with the ending boundary value and the ending output power, determine a derating control line with the first function point and the second function point, and control its own input voltage according to the derating control line.

[0014] According to an embodiment of the present application, the derating control line is a linear function line.

[0015] According to one embodiment of the present application, the inverter circuit is used to increase the output current of the DC string when the power converter controls the input voltage of the power converter itself based on the current output power and the limiting current range of the power converter, and the sum of the output powers of the DC strings is greater than or equal to the output power threshold.

[0016] In a second aspect, the present application provides a power converter, the power converter comprising a DC input terminal and a DC output terminal, the DC input terminal being used to connect a DC power supply, a plurality of the power converters being connected to form a DC string, the DC output terminal of each of the power converters in the DC string being connected in series to an input terminal of a DC conversion circuit of an inverter;

[0017] Among them, the power converter is used to obtain the current output power corresponding to the current output current when the current output current is greater than or equal to the limiting current threshold, and control the input voltage of the power converter itself based on the current output power and the limiting current range of the power converter.

[0018] According to the power converter of the present application, the two ends of multiple power converters connected in series are respectively connected to the two ends of the inverter, and each power converter is connected to a DC power supply. When the power converter detects that its own output current is greater than or equal to the limiting current threshold, it enters the current limiting state, and controls its own input voltage through the current output power and the limiting current range. The inverter can adjust the output power of multiple power converters, and the power converter performs derating control based on the current output power corresponding to the limiting current threshold as a reference parameter. The control of the input voltage is stable and controllable, the inverter can cooperate with the power converter to perform power adjustment, and the system operation has high stability.

[0019] In a third aspect, the present application provides a control method for a power converter, wherein the power converter comprises a DC input terminal and a DC output terminal, wherein the DC input terminal is used to connect a DC power supply, wherein a plurality of the power converters are connected to form a DC string, wherein the DC output terminal of each of the power converters in the DC string is connected in series to the input terminal of a DC conversion circuit of an inverter, wherein the method comprises:

[0020] When the current output current of the power converter is greater than or equal to the current limiting threshold, obtaining the current output power corresponding to the current output current;

[0021] Based on the current output power and a current limit range of the power converter, an input voltage of the power converter is controlled.

[0022] According to the control method of the power converter of the present application, the two ends of multiple power converters connected in series are respectively connected to the two ends of the inverter, and each power converter is connected to a DC power supply. When the power converter detects that its own output current is greater than or equal to the limiting current threshold, it enters the current limiting state, and controls its own input voltage through the current output power and the limiting current range. The inverter can adjust the output power of multiple power converters, and the power converter performs derating control based on the current output power corresponding to the limiting current threshold as the reference parameter. The control of the input voltage is stable and controllable, the inverter can cooperate with the power converter to perform power adjustment, and the system operation has high stability.

[0023] According to one embodiment of the present application, the limiting current range includes a starting boundary value and an ending boundary value, and the controlling the input voltage of the power converter based on the current output power and the limiting current range of the power converter includes:

[0024] Based on the current output power, the termination output power corresponding to the termination boundary value of the limiting current range is determined, and based on the starting boundary value of the limiting current range, the termination boundary value, the current output power and the termination output power, the input voltage of the power converter is controlled.

[0025] According to one embodiment of the present application, the starting boundary value is equal to the limiting current threshold.

[0026] According to one embodiment of the present application, the controlling the input voltage of the power converter based on the starting boundary value of the limiting current range, the ending boundary value, the current output power and the ending output power includes:

[0027] A first function point is determined by the starting boundary value and the current output power, a second function point is determined by the ending boundary value and the ending output power, a derating control line is determined by the first function point and the second function point, and the input voltage of the power converter is controlled according to the derating control line.

[0028] According to an embodiment of the present application, the derating control line is a linear function line.

[0029] In a fourth aspect, the present application provides an inverter, the inverter comprising at least one DC conversion circuit, a DC bus and an inverter circuit, the DC conversion circuit input end is connected to at least one DC string, each DC conversion circuit output end is connected to the DC bus in parallel, the inverter circuit input end is connected to the DC bus, the DC string comprises at least one power converter, the power converter comprises a DC input end and a DC output end, the DC input end is used to connect to a DC power supply, and the DC output end of each power converter in the DC string is connected in series to the input end of the DC conversion circuit;

[0030] Wherein, the power converter is used to obtain the current output power corresponding to the current output current when the current output current is greater than or equal to the limiting current threshold, and control the input voltage of the power converter itself based on the current output power and the limiting current range of the power converter;

[0031] The inverter circuit is used to perform maximum power point tracking when the output voltage of the DC string is less than the maximum power point voltage value and the sum of the output powers of the DC strings is less than an output power threshold.

[0032] According to the inverter of the present application, the two ends of multiple power converters connected in series are respectively connected to the two ends of the inverter, and each power converter is connected to a DC power supply. When the power converter detects that its own output current is greater than or equal to the limiting current threshold, it enters the current limiting state, and controls its own input voltage through the current output power and the limiting current range. The inverter can adjust the output power of multiple power converters, and the power converter performs derating control based on the current output power corresponding to the limiting current threshold as a reference parameter. The control of the input voltage is stable and controllable, the inverter can cooperate with the power converter to perform power regulation, and the system operation has high stability.

[0033] In a fifth aspect, the present application provides a control method for an inverter, wherein the inverter comprises at least one DC conversion circuit, a DC bus and an inverter circuit, wherein the DC conversion circuit input end is connected to at least one DC string, and each DC conversion circuit output end is connected to the DC bus in parallel, and the inverter circuit input end is connected to the DC bus, and the DC string comprises at least one power converter, and the power converter comprises a DC input end and a DC output end, and the DC input end is used to connect a DC power supply, and the DC output end of each power converter in the DC string is connected in series to the input end of the DC conversion circuit, and the method comprises:

[0034] When the power converter obtains the current output power corresponding to the current output current, the input voltage of the power converter itself is controlled based on the current output power and the limiting current range of the power converter, and the maximum power point tracking is performed when the output voltage of the DC string is less than the maximum power point voltage value and the sum of the output powers of the DC strings is less than the output power threshold.

[0035] According to the control method of the inverter of the present application, the two ends of multiple power converters connected in series are respectively connected to the two ends of the inverter, and each power converter is connected to a DC power supply. When the power converter detects that its own output current is greater than or equal to the limiting current threshold, it enters the current limiting state, and controls its own input voltage through the current output power and the limiting current range. The inverter can adjust the output power of multiple power converters, and the power converter performs derating control based on the current output power corresponding to the limiting current threshold as a reference parameter. The control of the input voltage is stable and controllable, the inverter can cooperate with the power converter to adjust the power, and the system operation has high stability.

[0036] In a sixth aspect, the present application provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the control method of the power converter as described in the third aspect above is implemented.

[0037] In a seventh 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 power converter as described in the third aspect above.

[0038] In an eighth 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 power converter as described in the third aspect above.

[0039] 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

[0040] 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:

[0041] Figure 1 is a schematic diagram of the structure of the power system provided in the embodiment of the present application;

[0042] Figure 2 is a schematic diagram of the structure of a DC string provided in an embodiment of the present application;

[0043] Figure 3 is a schematic diagram of the structure of the inverter provided in an embodiment of the present application;

[0044] Figure 4 is a schematic diagram of a derating control line provided in an embodiment of the present application;

[0045] Figure 5 It is one of the flow charts of the control method of the power converter provided in the embodiment of the present application;

[0046] Figure 6 This is a second flow chart of a method for controlling a power converter provided in an embodiment of the present application;

[0047] Figure 7 This is the third flow chart of the power converter control method provided in the embodiment of the present application.

[0048] Reference numerals:

[0049] Power system 100, DC string 120, power converter 121, DC power source 122, inverter 130,

[0050] DC conversion circuit 131 , DC bus 132 , inverter circuit 133 . DETAILED DESCRIPTION

[0051] 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.

[0052] 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.

[0053] Component-level power electronic devices (MLPE) such as optimizers can control their input voltage to operate near the maximum power point of the connected power source, but will not control their output voltage. The output of the optimizer is connected to the PV bus of the inverter. While the inverter controls the PV bus voltage, it indirectly controls the PV bus current, that is, the optimizer output current. For a single optimizer, it is necessary to limit the output current when overcurrent occurs to keep the current running within the normal range.

[0054] For power systems, most of them use multiple optimizers in series, in conjunction with inverters, to achieve maximum power point tracking control of multiple power sources. In a power system, when multiple optimizers are connected in series, and one or more of the multiple optimizers in series need to limit the output current, the inverter input power will not change significantly due to the full power output of other optimizers. Since the inverter controls the PV bus, the inverter input current basically does not change, and the output current of the optimizer cannot be controlled in the power system.

[0055] The power system 100 of the embodiment of the present application is used to implement current limiting control of the power converter 121. The power system 100, the power converter 121, the control method of the power converter 121, the electronic device and the readable storage medium provided in the embodiment of the present application are described in detail below with reference to the accompanying drawings through specific embodiments and their application scenarios.

[0056] like Figure 1 As shown, the power system 100 of the embodiment of the present application includes an inverter 130 and at least one DC string 120 .

[0057] like Figure 3As shown, the inverter 130 includes at least one DC conversion circuit 131, a DC bus 132 and an inverter circuit 133. The input end of the DC conversion circuit 131 is connected to at least one DC string 120, the output ends of each DC conversion circuit 131 are connected in parallel to the DC bus 132, and the input end of the inverter circuit 133 is connected to the DC bus 132. Figure 2 As shown, the DC string 120 includes at least one power converter 121, and the power converter 121 includes a DC input end and a DC output end. The DC input end is used to connect to a DC power source 122, and the DC output end of each power converter 121 in the DC string 120 is connected in series to the input end of the DC conversion circuit 131.

[0058] For example, the power system 100 includes a DC string 120, the DC string 120 includes multiple power converters 121, the DC output end of each power converter 121 in the DC string 120 is connected in series to the input end of the DC conversion circuit 131, and the inverter circuit 133 of the inverter 130 performs maximum power point tracking on the DC string 120, which can improve the efficiency and flexibility of the maximum power point tracking of the DC string 120.

[0059] For another example, the power system 100 includes multiple DC strings 120, each DC string 120 includes multiple power converters 121, and the multiple DC strings 120 are connected in parallel to the input end of the DC conversion circuit 131. The inverter circuit 133 of the inverter 130 tracks the maximum power point of the multiple DC strings 120, which can ensure the power generation efficiency of the power system 100 and is suitable for different lighting scenarios.

[0060] It should be noted that the power system 100 may include multiple DC conversion circuits 131 , the number of DC strings 120 connected to the input end of each DC conversion circuit 131 may be different, and the output ends of the multiple DC conversion circuits 131 are connected in parallel to the DC bus 132 .

[0061] The DC conversion circuit 131 is used to perform voltage conversion and other transformations on the DC power output by the DC string 120, the DC bus 132 is used to transmit the electric energy output by the DC conversion circuit 131 to the inverter circuit 133, and the inverter circuit 133 is used to convert the DC power input through the DC bus 132 into AC power.

[0062] The power converter 121 is used to convert the voltage, current, power, etc. output by the DC power supply 122. The DC power supply 122 is an energy storage device or energy conversion device for outputting direct current.

[0063] In this embodiment, the energy conversion device may be a photovoltaic module, and accordingly, the power converter 121 may be a photovoltaic optimizer.

[0064] In this embodiment, the positive output terminal of one power converter 121 can be connected to the negative output terminal of another power converter 121, and the positive output terminal of the connected power converter 121 can be connected to the negative output terminal of the next power converter 121, thereby obtaining a DC string 120.

[0065] For example, there are power converter 121a, power converter 121b and power converter 121c, the positive output terminal of power converter 121a is connected to the negative output terminal of power converter 121b, and the positive output terminal of power converter 121b is connected to the negative output terminal of power converter 121c.

[0066] For example, the power system 100 includes an inverter 130 and a DC string 120, multiple power converters 121 are connected in series, each power converter 121 is connected to a DC power source 122, and the DC output end of each power converter 121 in the DC string 120 is connected in series to the input end of the inverter 130.

[0067] In this embodiment, the power converter 121 is used to obtain the current output power corresponding to the current output current when the current output current is greater than or equal to the limiting current threshold, and control the input voltage of the power converter 121 itself based on the current output power and the limiting current range of the power converter 121.

[0068] The current output current is the current output by the power converter 121 at the current moment, and the current limiting threshold is the upper limit of the output current of the power converter 121 during normal operation.

[0069] In this embodiment, the limiting current threshold may be determined according to the rated current of the DC power source 122 connected to the power converter 121 and the operating parameters of the power converter 121 itself.

[0070] In this embodiment, the current at the output end of the power converter 121 is acquired in real time, and when the current output current reaches the current limiting threshold, the power converter 121 can be controlled to enter a current limiting state.

[0071] The current limiting state is a state in which the output current of the power converter 121 is limited so that the output current of the power converter 121 no longer increases or decreases slowly.

[0072] For example, the limiting current threshold is 20A, and the output current of the power converter 121 is acquired in real time. When the current output current reaches the limiting current threshold 20A, the output current of the power converter 121 can be controlled not to increase any more.

[0073] In this step, the output current of the power converter 121 can be obtained in real time through the microcontroller unit (MCU) of the power converter 121, and the current output current is compared with the limiting current threshold. When it is determined that the current output current reaches the limiting current threshold, the MCU can control the power converter 121 to enter the current limiting state.

[0074] For example, the limiting current threshold is 20A, and the MCU obtains the output current of the corresponding power converter 121 in real time. When the current output current obtained by the MCU reaches the limiting current threshold 20A, the MCU can control the output current of the power converter 121 to no longer increase.

[0075] In this embodiment, when the current output current is greater than or equal to the limiting current threshold, the power converter 121 obtains the current output power corresponding to the current output current.

[0076] The current output power is the output power of the power converter 121 corresponding to the current output current when the power converter 121 outputs current at the current moment.

[0077] It should be noted that the current moment is the moment when the power converter 121 enters the current limiting state.

[0078] In this embodiment, when the power converter 121 enters the current limiting state, the power converter 121 controls the input voltage of the power converter 121 itself based on the current output power and the limiting current range of the power converter 121 .

[0079] The limiting current range may be a current range for controlling the output current of the power converter 121 itself after the power converter 121 enters a current limiting state.

[0080] In this embodiment, the limiting current range may be a preset fixed range, and the relationship between the output power and the output current of the power converter 121 after the power converter 121 enters the current limiting state may be determined based on the current output power and the limiting current range.

[0081] According to the relationship between the output power and the output current after the power converter 121 enters the current limiting state, the target output power corresponding to the target output current that causes the power converter 121 to exit the current limiting state is determined.

[0082] By controlling the input voltage of the power converter 121 itself, the output power of the power converter 121 is controlled to reach the target output power, so that the output current of the power converter 121 reaches the target output current, and the power converter 121 exits the current limiting state.

[0083] In this embodiment, the inverter circuit 133 is used to perform maximum power point tracking when the output voltage of the DC string 120 is less than the maximum power point voltage value and the sum of the output powers of the DC string 120 is less than the output power threshold.

[0084] In this embodiment, the inverter circuit 133 has a maximum power point tracking (MPPT) function, and can perform maximum power point tracking on the output power of the DC string 120 .

[0085] The maximum power point voltage value may be a voltage value corresponding to the maximum power point of the output power of the DC string 120 .

[0086] The output power threshold is a critical value. When the output power of the DC string 120 is less than the output power threshold, the inverter circuit 133 can identify that the output power of the DC string 120 decreases from the maximum power point.

[0087] In this embodiment, after the inverter circuit 133 recognizes that the output power of the DC string 120 drops from the maximum power point, the inverter circuit 133 may perform maximum power point tracking by increasing the output voltage of the DC string 120 .

[0088] In the related art, the current limiting method of the power converter is voltage and current dual loop control, where the voltage loop is used as the given value of the current loop. If the output current needs to be limited, the upper limit of the voltage loop output is limited. This method will cause the output voltage of multiple power converters in the power system to fluctuate greatly near the current limiting point. The current loop responds quickly. Since the series connection will make the current of multiple power converters the same, the current loop cannot effectively feedback, which will continuously reduce the corresponding duty cycle. The output voltage of the power converter fluctuates greatly and may drop suddenly, which will also affect the operation of the inverter and the operation stability of the power system is poor.

[0089] According to the power system 100 provided in the embodiment of the present application, the two ends of multiple power converters 121 connected in series are respectively connected to the two ends of the inverter 130, and each power converter 121 is connected to a DC power supply 122. When the power converter 121 detects that its own output current is greater than or equal to the limiting current threshold, it enters the current limiting state, and controls its own input voltage through the current output power and the limiting current range. The inverter 130 can adjust the output power of multiple power converters 121, and the power converter 121 performs derating control based on the current output power corresponding to the limiting current threshold as the reference parameter. The control of the input voltage is stable and controllable, the inverter 130 can cooperate with the power converter 121 to perform power adjustment, and the system operation has high stability.

[0090] In some embodiments, the limiting current range includes a starting boundary value and an ending boundary value. When the current output current is greater than or equal to the limiting current threshold, the power converter 121 is used to determine the ending output power corresponding to the ending boundary value based on the current output power, and control its own input voltage based on the starting boundary value, the ending boundary value, the current output power and the ending output power.

[0091] The starting boundary value is the current value corresponding to the starting point of the limited current range, and the ending boundary value is the current value corresponding to the ending point of the limited current range.

[0092] In this embodiment, the termination output power is the corresponding output power when the output current of the power converter 121 is the termination boundary value. The relationship between the current output power and the termination output power can be pre-set. After obtaining the current output power, the termination output power is determined based on the relationship between the current output power and the termination output power.

[0093] In this embodiment, the starting boundary value may correspond to the current output power, and the ending boundary value may correspond to the ending output power. The relationship between the output power and the output current of the power converter 121 within the limiting current range may be determined based on the starting boundary value, the ending boundary value, the current output power and the ending output power.

[0094] In this embodiment, the target output power corresponding to the target output current that causes the power converter 121 to exit the current limiting state is determined according to the relationship between the output power and the output current after the power converter 121 enters the current limiting state.

[0095] By controlling the input voltage of the power converter 121 itself, the output power of the power converter 121 is controlled to reach the target output power, so that the output current of the power converter 121 reaches the target output current, and the power converter 121 exits the current limiting state.

[0096] In actual implementation, the output voltage of the power converter 121 can be controlled by a loop control method to increase the voltage control amount. The change of the voltage loop will affect the current loop, causing the output current of the power converter 121 to decrease, thereby reducing the output power of the power converter 121 to the target output power.

[0097] In this embodiment, by controlling the output voltage boost voltage control amount of the power converter 121, the output power of the power converter 121 can be controlled to stably decrease to the desired output power, thereby ensuring a higher output power while ensuring the safe operation of the power converter 121.

[0098] In some embodiments, the starting boundary value is equal to the limiting current threshold.

[0099] In this embodiment, the limiting current threshold is the starting boundary value of the limiting current range. When the current output current of the power converter 121 reaches the limiting current threshold, the power converter 121 begins to enter the current limiting state, and the output current of the power converter 121 enters the limiting current range.

[0100] It can be understood that the current output power is the power corresponding to the starting boundary value.

[0101] In this embodiment, the relationship between the output power and the output current of the power converter 121 within the current limiting range can be determined based on the current limiting threshold, the power corresponding to the starting boundary value, the ending boundary value and the ending output power.

[0102] According to the obtained relationship between the output power and the output current of the power converter 121 , the target output power corresponding to the target output current that causes the power converter 121 to exit the current limiting state is determined.

[0103] By controlling the input voltage of the power converter 121 itself, the output power of the power converter 121 can be controlled to reach the target output power, so that the output current of the power converter 121 reaches the target output current, and the power converter 121 can exit the current limiting state.

[0104] In some embodiments, the power converter 121 is used to determine a first function point with a starting boundary value and a current output power, determine a second function point with an ending boundary value and an ending output power, determine a derating control line with the first function point and the second function point, and control its own input voltage according to the derating control line.

[0105] Among them, the first function point is a function point determined in the two-dimensional function space by the starting boundary value and the current output power, the second function point is a function point determined in the two-dimensional function space by the ending boundary value and the ending output power, the derating control line is a function line passing through the first function point and the second function point, and the derating control line can be a curve or a straight line.

[0106] The derating control line may represent the relationship between the output power and the output current of the power converter 121 when the power converter 121 is in a current limiting state.

[0107] In this embodiment, the process of obtaining the derating control line is simple through the starting boundary value corresponding to the starting point of the limiting current range of the power converter 121 and the current output power, and the ending boundary value of the limiting current range and the ending output power. The obtained derating control line can accurately reflect the relationship between the output current and the output power of the power converter 121 in the current limiting state.

[0108] In this embodiment, the target output power corresponding to the target output current that causes the power converter 121 to exit the current limiting state is determined according to the derating control line.

[0109] By controlling the input voltage of the power converter 121 itself, the output power of the power converter 121 is controlled to reach the target output power, so that the output current of the power converter 121 reaches the target output current, and the power converter 121 exits the current limiting state.

[0110] In some embodiments, the derating control line is a linear function line.

[0111] For example, Figure 4 As shown, I 1 is the starting boundary value, I 2 is the termination boundary value, P 1 The current is I 1 The corresponding power at that time is the current output power, P 2 The current is I 2 The corresponding power when the output power is terminated, where P 2 =0.8×P 1 .

[0112] Then a linear function line can be fitted to obtain the derating function relationship P = f(I), and the target output current I 3 Substituting the derating function relationship P = f(I), we get the target output power P 3 .

[0113] In this embodiment, the first function point is determined by the starting boundary value and the current output power, and the second function point is determined by the ending boundary value and the ending output power. The derating control line of the linear function line can be determined by the first function point and the second function point.

[0114] According to the linear function line, the target output power corresponding to the target output current that causes the power converter 121 to exit the current limiting state can be determined. The functional relationship of the linear function line is simple. According to the linear function line, the process of controlling the input voltage of the power converter 121 is simple.

[0115] In some embodiments, the inverter circuit 133 is used to increase the output current of the DC string 120 when the power converter 121 controls the input voltage of the power converter 121 itself based on the current output power and the limiting current range of the power converter 121, and the sum of the output powers of the DC string 120 is greater than or equal to the output power threshold.

[0116] In this embodiment, due to MCU sampling errors, the triggering moments at which the power converters 121 in the DC string 120 enter the current limiting state may be different. When one power converter 121 in the DC string 120 enters the current limiting state, other power converters 121 may be on the verge of entering the current limiting state. However, at this time, the sum of the output powers of the DC string 120 may not change significantly and is still greater than or equal to the output power threshold.

[0117] The inverter circuit 133 can continue to increase the output current of the DC string 120, so that other power converters 121 that are on the verge of entering the current limiting state enter the current limiting state, so that the output power of the DC string 120 is reduced. The inverter circuit 133 can identify that the output power of the DC string 120 is less than the output power threshold.

[0118] After recognizing that the output power of the DC string 120 is less than the output power threshold, the inverter circuit 133 can control the output voltage of the DC string 120 and cooperate with the power converter 121 to perform power regulation, so that the power converter 121 in the DC string 120 that has entered the current limiting state exits the current limiting state.

[0119] After the power converter 121 of the DC string 120 exits the current limiting state, it can work normally and ensure the continuous power output of the DC string 120 .

[0120] The embodiment of the present application also provides a power converter 121 .

[0121] like Figure 2 As shown, the power converter 121 includes a DC input terminal and a DC output terminal. The DC input terminal is used to connect to a DC power source 122. Multiple power converters 121 are connected to form a DC string 120. The DC output terminal of each power converter 121 in the DC string 120 is connected in series to the input terminal of the DC conversion circuit 131 of the inverter 130.

[0122] Among them, the power converter 121 is used to obtain the current output power corresponding to the current output current when the current output current is greater than or equal to the limiting current threshold, and control the input voltage of the power converter 121 itself based on the current output power and the limiting current range of the power converter 121.

[0123] According to the power converter 121 provided in the embodiment of the present application, the two ends of the multiple power converters 121 connected in series are respectively connected to the two ends of the inverter 130, and each power converter 121 is connected to a DC power supply 122. When the power converter 121 detects that its own output current is greater than or equal to the limiting current threshold, it enters the current limiting state, and controls its own input voltage through the current output power and the limiting current range. The inverter 130 can adjust the output power of the multiple power converters 121, and the power converter 121 performs derating control based on the current output power corresponding to the limiting current threshold as the reference parameter. The control of the input voltage is stable and controllable. The inverter 130 can cooperate with the power converter 121 to perform power adjustment, and the system operation has high stability.

[0124] The embodiment of the present application also provides a control method for the power converter 121 .

[0125] The control method of the power converter 121 may be applied to a terminal, and may be specifically executed by hardware or software in the terminal.

[0126] The terminal includes, but is not limited to, a portable communication device such as a mobile phone or tablet computer with a touch-sensitive surface (e.g., a touch screen display and / or a touch pad). It should also be understood that in some embodiments, the terminal may not be a portable communication device, but a desktop computer with a touch-sensitive surface (e.g., a touch screen display and / or a touch pad).

[0127] In the following various embodiments, a terminal including a display and a touch-sensitive surface is described. However, it should be understood that the terminal may include one or more other physical user interface devices such as a physical keyboard, a mouse and a joystick.

[0128] The control method of the power converter 121 provided in the embodiment of the present application, the execution subject of the control method of the power converter 121 can be an electronic device or a functional module or functional entity in the electronic device that can implement the control method of the power converter 121. 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 power converter 121 provided in the embodiment of the present application is described below using the electronic device as an execution subject as an example.

[0129] In an embodiment of the present application, the power converter 121 includes a DC input terminal and a DC output terminal. The DC input terminal is used to connect to a DC power source 122. Multiple power converters 121 are connected to form a DC string 120. The DC output terminal of each power converter 121 in the DC string 120 is connected in series to the input terminal of the DC conversion circuit 131 of the inverter 130.

[0130] like Figure 5As shown, the control method of the power converter 121 includes: step 510 and step 520.

[0131] Step 510 : When the current output current of the power converter 121 is greater than or equal to the current limiting threshold, obtain the current output power corresponding to the current output current.

[0132] Step 520 : Control the input voltage of the power converter 121 based on the current output power and the current limit range of the power converter 121 .

[0133] According to the control method of the power converter 121 provided in the embodiment of the present application, the two ends of the multiple power converters 121 connected in series are respectively connected to the two ends of the inverter 130, and each power converter 121 is connected to a DC power supply 122. When the power converter 121 detects that its own output current is greater than or equal to the limiting current threshold, it enters the current limiting state, and controls its own input voltage through the current output power and the limiting current range. The inverter 130 can adjust the output power of the multiple power converters 121, and the power converter 121 performs derating control based on the current output power corresponding to the limiting current threshold as the reference parameter. The control of the input voltage is stable and controllable, the inverter 130 can cooperate with the power converter 121 to perform power adjustment, and the system operation has high stability.

[0134] In some embodiments, Figure 6 As shown, the limiting current range includes a starting boundary value and an ending boundary value. Based on the current output power and the limiting current range of the power converter 121, the input voltage of the power converter 121 is controlled, including:

[0135] Step 610: Based on the current output power, determine the termination output power corresponding to the termination boundary value of the limiting current range, and control the input voltage of the power converter 121 based on the starting boundary value, the termination boundary value, the current output power and the termination output power of the limiting current range.

[0136] In some embodiments, the starting boundary value is equal to the limiting current threshold.

[0137] In some embodiments, Figure 7 As shown, based on the starting boundary value, the ending boundary value, the current output power and the ending output power of the limiting current range, the input voltage of the power converter 121 is controlled, including:

[0138] Step 710, determine the first function point with the starting boundary value and the current output power, determine the second function point with the ending boundary value and the ending output power, determine the derating control line with the first function point and the second function point, and control the input voltage of the power converter 121 according to the derating control line.

[0139] In some embodiments, the derating control line is a linear function line.

[0140] The control method of the power converter 121 provided in the embodiment of the present application may be executed by a control device of the power converter 121. In the embodiment of the present application, the control device of the power converter 121 executing the control method of the power converter 121 is taken as an example to illustrate the control device of the power converter 121 provided in the embodiment of the present application.

[0141] The embodiment of the present application also provides a control device for the power converter 121 .

[0142] In the embodiment of the present application, the power converter 121 includes a DC input terminal and a DC output terminal. The DC input terminal is used to connect to a DC power source 122. The DC output terminals of multiple power converters 121 are connected in series to the input terminal of a DC conversion circuit 131 of an inverter 130.

[0143] The control device of the power converter 121 includes:

[0144] An acquisition module, used for acquiring a current output power corresponding to the current output current when the current output current of the power converter 121 is greater than or equal to the current limiting threshold;

[0145] The processing module is used to control the input voltage of the power converter 121 based on the current output power and the limited current range of the power converter 121 .

[0146] According to the control device of the power converter 121 provided in the embodiment of the present application, the two ends of the multiple power converters 121 connected in series are respectively connected to the two ends of the inverter 130, and each power converter 121 is connected to a DC power supply 122. When the power converter 121 detects that its own output current is greater than or equal to the limiting current threshold, it enters the current limiting state, and controls its own input voltage through the current output power and the limiting current range. The inverter 130 can adjust the output power of the multiple power converters 121. The power converter 121 performs derating control based on the current output power corresponding to the limiting current threshold as the reference parameter. The control of the input voltage is stable and controllable. The inverter 130 can cooperate with the power converter 121 to perform power adjustment, and the system operation has high stability.

[0147] In some embodiments, the limiting current range includes a starting boundary value and an ending boundary value, and the processing module is used to determine the ending output power corresponding to the ending boundary value of the limiting current range based on the current output power, and control the input voltage of the power converter 121 based on the starting boundary value, the ending boundary value, the current output power and the ending output power of the limiting current range.

[0148] In some embodiments, the starting boundary value is equal to the limiting current threshold.

[0149] In some embodiments, the processing module is used to determine a first function point with a starting boundary value and a current output power, determine a second function point with an ending boundary value and an ending output power, determine a derating control line with the first function point and the second function point, and control the input voltage of the power converter 121 according to the derating control line.

[0150] In some embodiments, the derating control line is a linear function line.

[0151] The control device of the power converter 121 in the embodiment of the present application can be an electronic device, or a component in the electronic device, such as an integrated circuit or a chip. The electronic device can be a terminal, or other devices other than a terminal. Exemplarily, the electronic device can be a tablet computer, a notebook computer, an ultra-mobile personal computer (ultra-mobile personal computer, UMPC), a server, a network attached storage (Network Attached Storage, NAS), a personal computer (personal computer, PC), etc., which is not specifically limited in the embodiment of the present application.

[0152] The control device of the power converter 121 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.

[0153] The control device of the power converter 121 provided in the embodiment of the present application can achieve Figure 5-Figure 7 To avoid repetition, the various processes implemented by the method embodiment are not described here.

[0154] The embodiment of the present application also provides an inverter 130 .

[0155] like Figure 3 As shown, the inverter 130 includes at least one DC conversion circuit 131, a DC bus 132 and an inverter circuit 133. The input end of the DC conversion circuit 131 is connected to at least one DC string 120. The output ends of each DC conversion circuit 131 are connected in parallel to the DC bus 132. The input end of the inverter circuit 133 is connected to the DC bus 132. The DC string 120 includes at least one power converter 121. The power converter 121 includes a DC input end and a DC output end. The DC input end is used to connect to the DC power supply 122. The DC output end of each power converter 121 in the DC string 120 is connected in series to the input end of the DC conversion circuit 131.

[0156] The power converter 121 is used to obtain the current output power corresponding to the current output current when the current output current is greater than or equal to the current limiting threshold, and control the input voltage of the power converter 121 itself based on the current output power and the current limiting range of the power converter 121;

[0157] The inverter circuit 133 is used to perform maximum power point tracking when the output voltage of the DC string 120 is less than the maximum power point voltage value and the sum of the output powers of the DC string 120 is less than the output power threshold.

[0158] According to the inverter 130 of the present application, the two ends of multiple power converters 121 connected in series are respectively connected to the two ends of the inverter 130, and each power converter 121 is connected to a DC power supply 122. When the power converter 121 detects that its own output current is greater than or equal to the limiting current threshold, it enters the current limiting state, and controls its own input voltage through the current output power and the limiting current range. The inverter 130 can adjust the output power of multiple power converters 121, and the power converter 121 performs derating control based on the current output power corresponding to the limiting current threshold as a reference parameter. The control of the input voltage is stable and controllable. The inverter 130 can cooperate with the power converter 121 to perform power adjustment, and the system operation has high stability.

[0159] The embodiment of the present application also provides a control method of the inverter 130 .

[0160] The inverter 130 includes at least one DC conversion circuit 131, a DC bus 132 and an inverter circuit 133. The input end of the DC conversion circuit 131 is connected to at least one DC string 120. The output ends of each DC conversion circuit 131 are connected in parallel to the DC bus 132. The input end of the inverter circuit 133 is connected to the DC bus 132. The DC string 120 includes at least one power converter 121. The power converter 121 includes a DC input end and a DC output end. The DC input end is used to connect to a DC power source 122. The DC output end of each power converter 121 in the DC string 120 is connected in series to the input end of the DC conversion circuit 131.

[0161] The control method of the inverter 130 includes:

[0162] When the power converter 121 obtains the current output power corresponding to the current output current, the input voltage of the power converter 121 itself is controlled based on the current output power and the limiting current range of the power converter 121, and the maximum power point tracking is performed when the output voltage of the DC string 120 is less than the maximum power point voltage value and the sum of the output powers of the DC string 120 is less than the output power threshold.

[0163] According to the control method of the inverter 130 of the present application, the two ends of multiple power converters 121 connected in series are respectively connected to the two ends of the inverter 130, and each power converter 121 is connected to a DC power supply 122. When the power converter 121 detects that its own output current is greater than or equal to the limiting current threshold, it enters the current limiting state, and controls its own input voltage through the current output power and the limiting current range. The inverter 130 can adjust the output power of multiple power converters 121, and the power converter 121 performs derating control based on the current output power corresponding to the limiting current threshold as a reference parameter. The control of the input voltage is stable and controllable. The inverter 130 can cooperate with the power converter 121 to perform power adjustment, and the system operation has high stability.

[0164] In some embodiments, the embodiments of the present application also provide an electronic device, including a processor, a memory, and a computer program stored in the memory and executable on the processor. When the program is executed by the processor, the various processes of the control method embodiment of the above-mentioned power converter 121 are implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0165] 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.

[0166] 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 power converter 121 are implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0167] 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.

[0168] The embodiment of the present application further provides a computer program product, including a computer program, which implements the control method of the power converter 121 when executed by a processor.

[0169] 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.

[0170] 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 control method embodiment of the above-mentioned power converter 121, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0171] 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.

[0172] 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.

[0173] 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.

[0174] 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.

[0175] 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.

[0176] 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 power system, characterized in that: include: Inverter and at least one DC string; The inverter comprises at least one DC conversion circuit, a DC bus and an inverter circuit, the DC conversion circuit input end is connected to at least one DC string, the output ends of each DC conversion circuit are connected to the DC bus in parallel, the inverter circuit input end is connected to the DC bus, the DC string comprises at least one power converter, the power converter comprises a DC input end and a DC output end, the DC input end is used to connect to a DC power source, and the DC output end of each power converter in the DC string is connected in series to the input end of the DC conversion circuit; Wherein, the power converter is used to obtain the current output power corresponding to the current output current when the current output current is greater than or equal to the limiting current threshold, and control the input voltage of the power converter itself based on the current output power and the limiting current range of the power converter; The inverter circuit is used to perform maximum power point tracking when the output voltage of the DC string is less than the maximum power point voltage value and the sum of the output powers of the DC strings is less than an output power threshold.

2. The power system according to claim 1, characterized in that: The limiting current range includes a starting boundary value and an ending boundary value. When the current output current is greater than or equal to the limiting current threshold, the power converter is used to determine the ending output power corresponding to the ending boundary value based on the current output power, and control its own input voltage based on the starting boundary value, the ending boundary value, the current output power and the ending output power.

3. The power system according to claim 2, characterized in that: The starting boundary value is equal to the limiting current threshold.

4. The power system according to claim 2, characterized in that: The power converter is used to determine a first function point with the starting boundary value and the current output power, determine a second function point with the ending boundary value and the ending output power, determine a derating control line with the first function point and the second function point, and control its own input voltage according to the derating control line.

5. The power system according to claim 4, characterized in that: The derating control line is a linear function line.

6. The power system according to any one of claims 1 to 5, characterized in that: The inverter circuit is used to increase the output current of the DC string when the power converter controls the input voltage of the power converter itself based on the current output power and the limiting current range of the power converter, and the sum of the output powers of the DC strings is greater than or equal to the output power threshold.

7. A power converter, characterized in that: The power converter comprises a DC input terminal and a DC output terminal, wherein the DC input terminal is used to connect a DC power source, and a plurality of the power converters are connected to form a DC string, wherein the DC output terminal of each power converter in the DC string is connected in series to the input terminal of the DC conversion circuit of the inverter; Among them, the power converter is used to obtain the current output power corresponding to the current output current when the current output current is greater than or equal to the limiting current threshold, and control the input voltage of the power converter itself based on the current output power and the limiting current range of the power converter.

8. A control method for a power converter, characterized in that: The power converter comprises a DC input terminal and a DC output terminal, wherein the DC input terminal is used to connect a DC power supply, and a plurality of the power converters are connected to form a DC string, wherein the DC output terminal of each power converter in the DC string is connected in series to the input terminal of a DC conversion circuit of an inverter, and the method comprises: When the current output current of the power converter is greater than or equal to the current limiting threshold, obtaining the current output power corresponding to the current output current; Based on the current output power and a current limit range of the power converter, an input voltage of the power converter is controlled.

9. The control method of the power converter according to claim 8, characterized in that: The limiting current range includes a starting boundary value and an ending boundary value, and the controlling the input voltage of the power converter based on the current output power and the limiting current range of the power converter includes: Based on the current output power, the termination output power corresponding to the termination boundary value of the limiting current range is determined, and based on the starting boundary value of the limiting current range, the termination boundary value, the current output power and the termination output power, the input voltage of the power converter is controlled.

10. The control method of the power converter according to claim 9, characterized in that: The starting boundary value is equal to the limiting current threshold.

11. The control method of the power converter according to claim 9, characterized in that: The step of controlling the input voltage of the power converter based on the starting boundary value of the limiting current range, the ending boundary value, the current output power, and the ending output power comprises: A first function point is determined by the starting boundary value and the current output power, a second function point is determined by the ending boundary value and the ending output power, a derating control line is determined by the first function point and the second function point, and the input voltage of the power converter is controlled according to the derating control line.

12. The control method of the power converter according to claim 11, characterized in that: The derating control line is a linear function line.

13. An inverter, characterized in that: The inverter includes at least one DC conversion circuit, a DC bus and an inverter circuit, the DC conversion circuit input end is connected to at least one DC string, the output ends of each DC conversion circuit are connected to the DC bus in parallel, the inverter circuit input end is connected to the DC bus, the DC string includes at least one power converter, the power converter includes a DC input end and a DC output end, the DC input end is used to connect to a DC power supply, and the DC output end of each power converter in the DC string is connected in series to the input end of the DC conversion circuit; Wherein, the power converter is used to obtain the current output power corresponding to the current output current when the current output current is greater than or equal to the limiting current threshold, and control the input voltage of the power converter itself based on the current output power and the limiting current range of the power converter; The inverter circuit is used to perform maximum power point tracking when the output voltage of the DC string is less than the maximum power point voltage value and the sum of the output powers of the DC strings is less than an output power threshold.

14. A control method for an inverter, characterized in that: The inverter comprises at least one DC conversion circuit, a DC bus and an inverter circuit, the DC conversion circuit input end is connected to at least one DC string, each DC conversion circuit output end is connected to the DC bus in parallel, the inverter circuit input end is connected to the DC bus, the DC string comprises at least one power converter, the power converter comprises a DC input end and a DC output end, the DC input end is used to connect to a DC power supply, the DC output end of each power converter in the DC string is connected in series to the input end of the DC conversion circuit, and the method comprises: When the power converter obtains the current output power corresponding to the current output current, the input voltage of the power converter itself is controlled based on the current output power and the limiting current range of the power converter, and the maximum power point tracking is performed when the output voltage of the DC string is less than the maximum power point voltage value and the sum of the output powers of the DC strings is less than the output power threshold.

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