Duty ratio adjusting method and charging equipment

Abstract

The invention discloses a duty ratio adjusting method and charging equipment, and the method comprises the steps: adjusting a first duty ratio to be gradually increased according to a target duty ratio and the output voltage of a power supply when the charging equipment is determined to be loaded, the first duty ratio is greater than or equal to the target duty ratio and / or the output voltage of the power supply is less than or equal to the minimum output voltage of the power supply; adjusting the first duty ratio according to the output power of the power supply and the disturbance direction when the first duty ratio is disturbed; generating a maximum output current according to the output voltage of the charging equipment and the maximum output voltage of the charging equipment; generating a second duty ratio according to the maximum output current and a first output current of the charging equipment; and determining a third duty ratio according to the minimum value of the adjusted first duty ratio and the adjusted second duty ratio, and setting the first duty ratio as the third duty ratio. Through the mode, the working stability and reliability of the photovoltaic module can be improved, and the maximum power of the photovoltaic module can be tracked more reliably.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of duty cycle regulation, and in particular to a duty cycle regulation method and a charging device. Background Art

[0002] When the output voltage of the photovoltaic module matches the operating voltage range of the energy storage device, the energy storage device can be directly connected to the photovoltaic module for use. When the voltage output by the photovoltaic module exceeds the voltage range required for the energy storage device to work safely or effectively, a charging device is required to adjust the output voltage of the photovoltaic module. This charging device usually has a step-down function that can adjust the voltage generated by the photovoltaic module to a level suitable for the energy storage device to accept. Summary of the invention

[0003] The embodiments of the present application provide a duty cycle adjustment method and a charging device, which can improve the stability and reliability of the operation of a photovoltaic module and can more reliably track the maximum power of the photovoltaic module.

[0004] In a first aspect, an embodiment of the present application provides a duty cycle adjustment method for adjusting a first duty cycle of a first pulse width modulation signal applied to a charging device, wherein the charging device is connected to a power supply, and the method comprises: when determining that the charging device is loaded, performing the following steps: adjusting the first duty cycle to gradually increase according to a target duty cycle and an output voltage of the power supply until the first duty cycle is greater than or equal to the target duty cycle and / or the output voltage of the power supply is less than or equal to the minimum output voltage of the power supply; adjusting the first duty cycle according to the output power of the power supply and the disturbance direction when the first duty cycle is disturbed, wherein when the average value of the output power of the current adjustment cycle decreases relative to the average value of the output power of the previous adjustment cycle, the disturbance direction is the first direction, and the duration of the adjustment cycle is the duration of adjusting the first duty cycle once; generating a maximum output current of the charging device according to the output voltage of the charging device and the maximum output voltage of the charging device; generating a second duty cycle according to the maximum output current and the first output current of the charging device; determining a third duty cycle according to the minimum value of the adjusted first duty cycle and the second duty cycle, and setting the first duty cycle to the third duty cycle.

[0005] In one or more embodiments, the step of adjusting the first duty cycle to gradually increase according to the target duty cycle and the output voltage of the power supply includes: in each adjustment cycle, when the first duty cycle is less than the target duty cycle and the output voltage of the power supply is greater than the minimum output voltage, adjusting the first duty cycle to be the sum of the first duty cycle and the first preset increase value, so as to adjust the first duty cycle to gradually increase.

[0006] In one or more embodiments, after executing the step of adjusting the first duty cycle to the sum of the first duty cycle and the first preset increase value, the method also includes: when the average value of the output power of the current adjustment cycle is greater than the recorded maximum power, the average value of the output power of the current adjustment cycle is recorded as the maximum power, and the adjusted first duty cycle is recorded as the first duty cycle corresponding to the maximum power.

[0007] In one or more embodiments, before executing the step of adjusting the first duty cycle to gradually increase according to the target duty cycle and the output voltage of the power supply until the first duty cycle is greater than or equal to the target duty cycle and / or the output voltage of the power supply is less than or equal to the minimum output voltage of the power supply, the method also includes: determining whether the preliminary adjustment process of the first duty cycle has been completed; if not, executing the step of adjusting the first duty cycle to gradually increase according to the target duty cycle and the output voltage of the power supply until the first duty cycle is greater than or equal to the target duty cycle and / or the output voltage of the power supply is less than or equal to the minimum output voltage of the power supply; if so, executing the step of adjusting the first duty cycle according to the output power of the power supply and the disturbance direction when the first duty cycle is disturbed; after executing the step of adjusting the first duty cycle to gradually increase according to the target duty cycle and the output voltage of the power supply until the first duty cycle is greater than or equal to the target duty cycle and / or the output voltage of the power supply is less than or equal to the minimum output voltage of the power supply, the method also includes: determining that the preliminary adjustment process of the first duty cycle has been completed; and recording the adjusted first duty cycle as the first duty cycle corresponding to the maximum power.

[0008] In one or more embodiments, the method further includes: determining a preset target value according to 1 / K, a ratio of an output voltage of the charging device to an input voltage of the charging device, wherein K is greater than 0 and less than 1.

[0009] In one or more embodiments, the step of adjusting the first duty cycle according to the output power of the power supply and the disturbance direction when the first duty cycle is disturbed includes: when it is determined that the disturbance direction of the current adjustment cycle is the first direction, recording the average value of the output power of the current adjustment cycle as the maximum power, and adjusting the direction of the disturbance amount of the first duty cycle to be in the reverse direction, and adjusting the disturbance direction not to be the first direction.

[0010] In one or more embodiments, the step of adjusting the first duty cycle according to the output power of the power supply and the disturbance direction when the first duty cycle is disturbed includes: when it is determined that the disturbance direction of the current adjustment cycle is not the first direction, executing the following steps: if the average value of the output power of the current adjustment cycle is less than the recorded maximum power, or the current value of the output voltage of the charging device is less than the minimum output voltage, then adjusting the disturbance direction to the first direction; if the average value of the output power of the current adjustment cycle is greater than or equal to the recorded maximum power, and the current value of the output voltage of the charging device is greater than or equal to the minimum output voltage, then recording the average value of the output power of the current adjustment cycle as the maximum power, and adjusting the duty cycle to the sum of the current value and the disturbance amount.

[0011] In one or more embodiments, after executing the step of adjusting the first duty cycle according to the output power of the power supply and the disturbance direction when the first duty cycle is disturbed, the method also includes: when the first duty cycle is greater than the maximum duty cycle, adjusting the disturbance direction to the first direction and setting the first duty cycle to the maximum duty cycle.

[0012] In one or more embodiments, after executing the step of adjusting the first duty cycle according to the output power of the power supply and the disturbance direction when the first duty cycle is disturbed, the method also includes: when the first duty cycle is less than the maximum duty cycle and the first duty cycle is less than the minimum duty cycle, adjusting the disturbance direction to the first direction and setting the first duty cycle to the minimum duty cycle.

[0013] In one or more embodiments, a maximum output current of the charging device is generated based on the output voltage of the charging device and the maximum output voltage of the charging device, including: performing PI adjustment on the difference between the output voltage of the charging device and the maximum output voltage to generate the maximum output current; and a first duty cycle is generated based on the maximum output current and the first output current of the charging device, including: performing PI adjustment on the difference between the maximum output current and the first output current to generate a second duty cycle.

[0014] In the second aspect, an embodiment of the present application provides a charging device, including: a charging circuit, connected to a power supply, and configured to output a bus voltage based on the voltage output by the power supply; a first control unit, connected to the charging circuit, and used to adjust the duty cycle of a first pulse width modulation signal applied to the charging device, including: at least one processor and a memory; the memory is coupled to the processor, and the memory is used to store instructions or programs, and when the instructions or programs are executed by at least one processor, the at least one processor executes the duty cycle adjustment method as above.

[0015] The beneficial effects of the present application are as follows: the duty cycle adjustment method of the embodiment of the present application is used to adjust the first duty cycle of the first pulse width modulation signal applied to the charging device, and the charging device is connected to the power supply. When the power supply is a photovoltaic module and it is determined that the charging device is loaded, firstly, according to the preset target duty cycle and the output voltage of the power supply, the first duty cycle is adjusted to gradually increase, that is, the first duty cycle is pulled up at a slower growth rate at the beginning, so as not to cause the abnormal situation that the output voltage of the photovoltaic module is continuously pulled down, which is conducive to improving the stability of the photovoltaic module and providing stable power supply; then, the first duty cycle is adjusted according to the output power of the power supply and the disturbance direction of the first duty cycle. At this time, under the condition of stable power supply of the photovoltaic module, the maximum power of the photovoltaic module can be tracked more reliably according to the output power and the disturbance direction. At the same time, according to the output voltage of the charging device and the maximum output voltage of the charging device, the maximum output current of the charging device is generated, and according to the maximum output current and the first output current of the charging device, the second duty cycle is generated, which can realize the constant voltage and current limiting functions. Finally, the third duty cycle is determined according to the minimum value of the adjusted first duty cycle and the second duty cycle, and the first duty cycle is set to the third duty cycle. This enables the charging device to simultaneously have the functions of constant voltage, current limiting and tracking the maximum power of the photovoltaic module, which is beneficial to improving the stability and reliability of the photovoltaic module. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] One or more embodiments are exemplarily described by the figures in the accompanying drawings, which are not intended to limit the embodiments. Elements with the same reference numerals in the drawings represent similar elements.

[0017] Figure 1 This is a schematic diagram of a charging control system provided in an embodiment of the present application. Figure 1 ; Figure 2 This is a schematic diagram of a charging control system provided in an embodiment of the present application. Figure 2 ; Figure 3 This is a schematic diagram of a charging control system provided in an embodiment of the present application. Figure 3 ; Figure 4 The process of the duty cycle adjustment method provided in the embodiment of the present application is Figure 1 ; Figure 5 The embodiment of this application provides Figure 4 A schematic diagram of an implementation of step S420 shown in FIG. Figure 6 The process of the duty cycle adjustment method provided in the embodiment of the present application is Figure 2 ; Figure 7 The embodiment of this application provides Figure 4A schematic diagram of an implementation of step S430 shown in FIG. Figure 8 The embodiment of this application provides Figure 4 A schematic diagram of another implementation of step S430 shown in FIG. Fig. 9 The embodiment of the present application provides that after the execution is completed Figure 4 A flowchart of steps further performed after step S430 shown in FIG. Fig.10 This is an embodiment of the present application Figure 4 A schematic diagram of an implementation of step S440 and step S450 shown in FIG. Fig.11 The embodiment of the present application provides Fig.10 Schematic diagram of the control method corresponding to the steps shown; Fig.12 The process of the duty cycle adjustment method of the embodiment of the present application is Figure 3 ; Fig.13 The process of the duty cycle adjustment method provided in the embodiment of the present application is Figure 4 ; Fig.14 The embodiment of this application provides Fig.13 A schematic diagram of an implementation of step S1310 shown in FIG. Fig.15 This is a step of setting a preset duty cycle provided in an embodiment of the present application; Fig.16 This is a method for determining AC component, peak value and frequency provided in an embodiment of the present application; Fig.17 is a schematic diagram of a control method of an energy storage device provided in an embodiment of the present application; Fig.18 The embodiment of this application provides Fig.13 A schematic diagram of an implementation of step S1340 shown in FIG. Fig.19 The embodiment of this application provides Fig.18 A schematic diagram of an implementation of step S1830 is shown in FIG. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and in detail in combination with the drawings 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. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0019] It should be noted that, when an element is described as being “connected to” another element, it may be directly connected to the other element, or one or more intervening elements may exist therebetween.

[0020] In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as there is no structural conflict between them.

[0021] Please refer to Figure 1 , Figure 1 A schematic diagram of an application scenario provided in an embodiment of the present application. The application scenario is a charging control system 100. The charging control system 100 includes a charging device 10, an energy storage device 20 and a power source 30.

[0022] The power source 30 is used to provide a continuous and stable voltage and current. In some embodiments, the power source 30 is a photovoltaic module, which is a functional unit that can independently output direct current formed by connecting multiple single solar cells in series or in parallel, and after being packaged and protected. The photovoltaic module is used to directly convert sunlight energy into electrical energy.

[0023] The energy storage device 20 is a device for storing electrical energy or other forms of energy and releasing it when needed. The energy storage device 20 inputs the bus voltage VBUS and the second pulse width modulation (PWM) signal. The energy storage device 20 is used to store energy based on the bus voltage VBUS in response to the second pulse width modulation signal. In a specific embodiment, the energy storage device 20 boosts or bucks the bus voltage VBUS in response to the second pulse width modulation signal, and stores energy based on the boosted or bucked voltage.

[0024] The charging device 10 is a device connected to the energy storage device 20 and provides electric energy to the energy storage device 20. In some embodiments, the charging device 10 inputs a first pulse width modulation signal, and converts the voltage output by the power supply 30 into a bus voltage VBUS in response to the first pulse width modulation signal, wherein the connection line between the charging device 10 and the energy storage device 20 is a bus. In a specific embodiment, the charging device 10 steps down the voltage output by the power supply 30 in response to the first pulse width modulation signal to obtain the bus voltage VBUS.

[0025] In some embodiments, Figure 2As shown, the charging device 10 includes a charging circuit 11 and a first control unit 12. The charging circuit 11 is used to step down the voltage output by the power supply 30 in response to the first pulse width modulation signal to obtain the bus voltage VBUS. The first control unit 12 is used to output the first pulse width modulation signal. The first control unit 12 can be a microcontroller unit (MCU) or a digital signal processing (DSP) controller.

[0026] The energy storage device 20 includes an energy storage circuit 21 and a second control unit 22. The energy storage circuit 21 is used to boost or buck the bus voltage VBUS in response to the second pulse width modulation signal, and store energy based on the boosted or bucked voltage. The second control unit 22 is used to output the second pulse width modulation signal. The second control unit 22 can be a microcontroller unit (MCU) or a digital signal processing (DSP) controller.

[0027] Figure 3 The circuit structure of the charging circuit 11 and the first control unit 12 is shown as an example. Figure 3 As shown, the charging circuit 11 includes a first NMOS transistor Q1, a first diode D1, a first inductor L1 and a first capacitor C1. The gate of the first NMOS transistor Q1 inputs a first pulse width modulation signal, the source of the first NMOS transistor Q1 is respectively connected to the cathode of the first diode D1 and the first end of the first inductor L1, the drain of the first NMOS transistor Q1 is connected to the positive electrode of the power source 30, the second end of the first inductor L1 is respectively connected to the first end of the first capacitor C1 and the positive electrode of the energy storage device 20, and the anode of the first diode D1 is respectively connected to the negative electrode of the power source 30, the second end of the first capacitor C1 and the negative electrode of the energy storage device 20.

[0028] Specifically, the first NMOS transistor Q1 is turned on or off in response to the first pulse width modulation signal to step down the output voltage of the power source 30 and obtain the bus voltage VBUS, which is input to the energy storage device 20 .

[0029] The first control unit 12 includes at least one processor 121 and a memory 122, wherein the memory 122 may be built in the first control unit 12 or may be external to the first control unit 12. The memory 122 may also be a remotely set memory connected to the first control unit 12 via a network.

[0030] The memory 122, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer executable programs and modules. The memory 122 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created according to the use of the terminal, etc. In addition, the memory 122 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device. In some embodiments, the memory 122 may optionally include a memory remotely arranged relative to the processor 121, and these remote memories may be connected to the terminal via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0031] The processor 121 performs various functions of the terminal and processes data by running or executing software programs and / or modules stored in the memory 122, and calling data stored in the memory 122, thereby monitoring the terminal as a whole, for example, implementing the steps performed by the charging device 10 in the duty cycle adjustment method in any embodiment of the present application.

[0032] The processor 121 may be one or more, Figure 3 In the figure, a processor 121 is taken as an example. The processor 121 and the memory 122 may be connected via a bus or other means. The processor 121 may include a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a controller, a field programmable gate array (FPGA) device, etc. The processor 121 may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration.

[0033] Figure 3 A circuit structure of the energy storage circuit 21 and the second control unit 22 is also exemplarily shown. Figure 3As shown, the energy storage circuit 21 includes a second NMOS transistor Q2, a third NMOS transistor Q3, a second diode D2, a third diode D2, a second inductor L2, a first capacitor C1, a second capacitor C2 and a battery B1. Among them, one of the gate of the second NMOS transistor Q2 and the gate of the third NMOS transistor Q3 inputs the second pulse width modulation signal, and the other inputs the low level signal, the source of the second NMOS transistor Q2 is respectively connected to the cathode of the second diode D2 and the first end of the second inductor L2, the drain of the second NMOS transistor Q2 is connected to the charging circuit 11, the second end of the second inductor L2 is respectively connected to the drain of the third NMOS transistor Q3 and the anode of the third diode D2, the cathode of the third diode D2 is respectively connected to the first end of the second capacitor C2 and the positive electrode of the battery B1, and the anode of the second diode D2 is respectively connected to the source of the third switch tube Q3, the second end of the second capacitor C2, the negative electrode of the battery B1 and the charging device 11.

[0034] Specifically, one of the second NMOS transistor Q2 and the third NMOS transistor Q3 is turned on or off in response to the second pulse width modulation signal, and the other remains off to boost or buck the bus voltage VBUS, and charge the battery B1 based on the boosted or bucked voltage to store energy.

[0035] The second control unit 22 includes at least one processor 221 and a memory 222, wherein the memory 222 may be built in the second control unit 22 or may be external to the second control unit 22. The memory 222 may also be a remotely set memory connected to the second control unit 22 via a network.

[0036] The memory 222, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer executable programs and modules. The memory 222 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, at least one application required for a function; the data storage area may store data created according to the use of the terminal, etc. In addition, the memory 222 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device. In some embodiments, the memory 222 may optionally include a memory remotely arranged relative to the processor 221, and these remote memories may be connected to the terminal via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0037] The processor 221 performs various functions of the terminal and processes data by running or executing software programs and / or modules stored in the memory 222, and calling data stored in the memory 222, thereby monitoring the terminal as a whole, for example, implementing the steps performed by the energy storage device 20 in the duty cycle adjustment method in any embodiment of the present application.

[0038] The processor 221 may be one or more, Figure 3 A processor 221 is taken as an example. The processor 221 and the memory 222 may be connected via a bus or other means. The processor 221 may include a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a controller, a field programmable gate array (FPGA) device, etc. The processor 221 may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration.

[0039] Please refer to Figure 4 , Figure 4 Flow chart of the duty cycle adjustment method provided in the embodiment of the present application. The duty cycle adjustment method is used to adjust the duty cycle (referred to as the first duty cycle D1) of a first pulse width modulation signal applied to a charging device, wherein the charging device is connected to a power source. In some embodiments, the charging device here can be Figure 1-Figure 3 The structure shown in the figure is implemented, and the specific implementation process has been described in detail in the above embodiment, which will not be repeated here. Figure 4 As shown, the duty cycle adjustment method includes the following steps: Step S410: Determine whether the charging device is loaded.

[0040] The embodiment of the present application also provides a step of determining whether the charging device 10 is loaded, that is, the duty cycle adjustment method further includes the following steps: obtaining the output current (i.e., the first output current) and the output voltage of the charging device 10; if the duration of the output current being equal to 0 is greater than the preset duration, then determining that the charging device 10 is unloaded; if the output current is greater than 0, and the output voltage of the charging device 10 sampled in the current sampling cycle is greater than the output voltage of the charging device 10 sampled in the previous sampling cycle, then determining that the charging device 10 is loaded. In some embodiments, the preset duration is configured as the product of the ratio of the preset maximum value (i.e., the maximum duty cycle) of the first duty cycle D1 to the first preset increase value and the adjustment period.

[0041] When it is determined that the charging device is loaded, subsequent steps S420 to S430 are executed.

[0042] Step S420: According to the target duty cycle and the output voltage of the power supply, the first duty cycle is adjusted to gradually increase until the first duty cycle is greater than or equal to the target duty cycle and / or the output voltage of the power supply is less than or equal to the minimum output voltage of the power supply.

[0043] The target duty cycle is a preset target value of the duty cycle, which can be set according to the actual application scenario. In some embodiments, the target duty cycle is determined according to 1 / K, the ratio of the output voltage of the charging device to the input voltage of the charging device (that is, the output voltage of the power supply), where K is greater than 0 and less than 1. Figure 3 The circuit structure of the charging device 10 shown, when it works in continuous conduction mode (Continuous Conduction Mode, CCM), the ratio of the output voltage of the charging device 10 to the input voltage is equal to the first duty cycle D1, and the target duty cycle is determined by 1 / K of the ratio. When the first duty cycle D1 is greater than or equal to the target duty cycle and / or the output voltage of the power supply 30 is less than or equal to the minimum output voltage, the first duty cycle D1 can be close to the duty cycle corresponding to the target maximum power, so as to facilitate the subsequent rapid tracking to the target maximum power. The target maximum power is the maximum value of the average value of the output power of one adjustment cycle. In a specific embodiment, when the power supply 30 is a photovoltaic module, K is set to 0.8.

[0044] Specifically, after the charging device 10 starts to operate, according to the target duty cycle and the output voltage of the power supply 30 (here, it refers to the actual output voltage of the power supply 30), the first duty cycle D1 is adjusted to gradually increase (it can be understood that when the first duty cycle D1 is adjusted to gradually increase, the current value of the first duty cycle D1 is adjusted), wherein, the first duty cycle D1 can be increased by reducing the increase rate of the first duty cycle D1, that is, the first duty cycle D1 is pulled up at a slower growth rate at the beginning, so that in the process of adjusting the first duty cycle D1, there will be no over-adjustment of the first duty cycle D1, thereby not causing over-adjustment of the output voltage of the power supply 30, and not causing the abnormal situation that the output voltage of the power supply 30 is continuously pulled down. When the power supply 30 is a photovoltaic module, it is beneficial to improve the stability of the photovoltaic module to provide stable power supply. Secondly, the target duty cycle can also be set according to experience to be close to the first duty cycle D1 corresponding to the target maximum power, and then, after the process of adjusting the first duty cycle D1 to gradually increase is completed, the first duty cycle D1 corresponding to the target maximum power can be quickly adjusted.

[0045] It can be understood that after the charging device 10 starts to operate, when the output voltage of the power supply 30 is greater than its minimum value (i.e., the minimum output voltage that the power supply 30 can output during normal operation), it is determined that the power supply 30 can provide voltage normally. In this case, it is only necessary to adjust the first duty cycle D1 to gradually increase according to the target duty cycle. Of course, in the process of adjusting the first duty cycle D1 to gradually increase, as long as the output voltage of the power supply 30 is less than or equal to its minimum value to determine that the power supply 30 cannot provide voltage normally, the first duty cycle D1 should be stopped from being adjusted to gradually increase, so as to prevent the abnormal situation that the output voltage of the power supply 30 continues to be pulled down.

[0046] In some embodiments, Figure 5 As shown, the specific implementation process of step S420 includes the following steps: Step S510: In each adjustment cycle, when the first duty cycle is less than the target duty cycle and the output voltage of the power supply is greater than the minimum output voltage, the first duty cycle is adjusted to be the sum of the first duty cycle and the first preset increase value, so as to adjust the first duty cycle to gradually increase.

[0047] The first preset increase value is the increase value of the preset first duty cycle D1, which can be set according to the actual application scenario. The first preset increase value is the increase value of each adjustment cycle. The larger the first preset increase value, the faster the growth rate of the first duty cycle D1; conversely, the smaller the first preset increase value, the slower the growth rate of the first duty cycle D1. The first preset increase values ​​of different adjustment cycles can be the same or different.

[0048] In a specific embodiment, the first preset increase value is recorded as DA and remains unchanged, the target duty cycle is recorded as DT, the output voltage of the power supply 30 is recorded as VR, and the minimum output voltage of the power supply 30 is recorded as VRM. It is assumed that in the first adjustment cycle, D1<DT, and VR>VRM, then D1=D1+DA, the duty cycle increases for the first time, and the increased first duty cycle D1 is applied to the charging device 10, entering the second adjustment cycle; in the second adjustment cycle, D1<DT, and VR>VRM, then D1=D1+DA, the duty cycle increases for the second time, and the increased first duty cycle D1 is applied to the charging device 10, entering the third adjustment cycle; ...; and so on, until D1≥DT and / or VR≤VRM, the duty cycle adjustment stops, that is, step S420 stops. In some embodiments, after executing step S510 to adjust the first duty cycle to the sum of the first duty cycle and the first preset increase value, the duty cycle adjustment method also includes the following steps: when the average value of the output power of the current adjustment cycle is greater than the recorded maximum power, the average value of the output power of the current adjustment cycle is recorded as the maximum power, and the adjusted first duty cycle is recorded as the first duty cycle corresponding to the maximum power.

[0049] The recorded maximum power refers to the highest output power value recorded in all previous adjustment cycles since the charging device 10 started to operate. It can be understood that the maximum power is also obtained by the average value of the output power of one adjustment cycle. The adjusted first duty cycle D1 is the sum of the first duty cycle D1 and the first preset increase value.

[0050] Specifically, after each adjustment of the first duty cycle D1 to the sum of the first duty cycle D1 and the first preset increase value, the adjusted first duty cycle D1 is applied to the charging device 10, and the average value of the output power of the current adjustment cycle is determined. If the average value of the output power of the current adjustment cycle is greater than the recorded maximum power, the average value of the output power of the current adjustment cycle is recorded as the maximum power, so as to continuously update the maximum power in real time according to the actual application situation, which is helpful to find the target maximum power that the photovoltaic module can provide more quickly later.

[0051] In some embodiments, Figure 6 As shown, before executing step S420, the duty cycle adjustment method further includes the following steps: determining whether the preliminary adjustment process of the first duty cycle has been completed. If it is determined that the preliminary adjustment process of the first duty cycle has not been completed, step S420 is executed; if it is determined that the preliminary adjustment process of the first duty cycle has been completed, step S430 is executed. Correspondingly, after executing step S420, the duty cycle adjustment method further includes the following steps: determining that the preliminary adjustment process of the first duty cycle has been completed, and recording the adjusted first duty cycle as the first duty cycle corresponding to the maximum power.

[0052] Specifically, the preliminary adjustment process of the first duty cycle D1 refers to the process of gradually increasing the first duty cycle D1. The process is completed when the first duty cycle D1 is greater than or equal to the target duty cycle and / or the output voltage of the power supply 30 is less than or equal to the minimum output voltage; the process is not completed when the first duty cycle D1 is less than the target duty cycle and the output voltage of the power supply 30 is greater than the minimum output voltage. If the preliminary adjustment process of the first duty cycle D1 is not completed, step S420 is performed until the first duty cycle D1 is greater than or equal to the target duty cycle and / or the output voltage of the power supply 30 is less than or equal to the minimum output voltage. After that, it is determined that the preliminary adjustment process of the first duty cycle D1 is completed, and the adjusted first duty cycle D1 is recorded as the first duty cycle D1 corresponding to the maximum power. Thus, after the charging device 10 starts to operate, the first duty cycle D1 is adjusted to gradually increase according to the target duty cycle and the output voltage of the power source 30. In this process, the adjustment amplitude of the first duty cycle D1 is small, so that the growth rate of the first duty cycle D1 is slow, so that there will be no over-adjustment of the duty cycle, and the abnormal situation of the output voltage of the power source 30 continuously being pulled down will not occur. When the power source 30 is a photovoltaic module, it is beneficial to improve the stability of the photovoltaic module to provide stable power supply.

[0053] Afterwards, since it is determined in the current adjustment cycle that the preliminary adjustment of the first duty cycle D1 has been completed, step S430 is performed in the next adjustment cycle.

[0054] Step S430: Adjust the first duty cycle according to the output power of the power supply and the disturbance direction when the first duty cycle is disturbed, wherein when the average value of the output power in the current adjustment cycle decreases relative to the average value of the output power in the previous adjustment cycle, the disturbance direction is the first direction, and the duration of the adjustment cycle is the duration of adjusting the first duty cycle once.

[0055] The disturbance to the first duty cycle D1 refers to applying a disturbance amount (usually a small disturbance amount) to the first duty cycle D1, the disturbance amount is an increment or a decrement, and observing the change in the output (such as power, voltage, current, etc., in this embodiment, power is taken as an example) of the charging device 10 caused thereby. According to the result of the output response (i.e., the change in the output power of the power source 30), it is determined whether the actual disturbance direction is the first direction, and then it is determined whether to continue to adjust the first duty cycle D1, so as to gradually approach the optimal working point of the charging device 10.

[0056] In some embodiments, Figure 7 As shown, the specific implementation process of step S430 includes the following steps: Step S710: When it is determined that the disturbance direction of the current adjustment cycle is the first direction, the average value of the output power of the current adjustment cycle is recorded as the maximum power, and the direction of the disturbance amount for disturbing the first duty cycle is adjusted to the reverse direction, and the disturbance direction is adjusted not to the first direction.

[0057] Specifically, after the current disturbance direction is the first direction corresponding to the first duty cycle D1 of the current adjustment cycle applied to the charging device 10, the average value of the output power of the current adjustment cycle decreases relative to the average value of the output power of the previous adjustment cycle. And, at this time, the target maximum power may have been exceeded. In this case, the average value of the output power of the current adjustment cycle is recorded as the maximum power, and the direction of the disturbance amount of the disturbance of the first duty cycle D1 is adjusted to the reverse direction, in the expectation that the average value of the output power of the next adjustment cycle increases relative to the average value of the output power of the current adjustment cycle, thereby reapproaching the target maximum power.

[0058] It can be understood that the disturbance amount in the embodiment of the present application includes a direction and a value, that is, the disturbance amount can be a positive value or a negative value. For example, assuming that before executing step S710, the disturbance amount is a value greater than 0 (such as P1), disturbing the first duty cycle D1 means increasing the first duty cycle D1; and after executing step S710, the direction of the disturbance amount is adjusted to the reverse direction, then the disturbance amount is a value less than 0 (-P1), and disturbing the first duty cycle D1 means reducing the first duty cycle D1.

[0059] In some embodiments, Figure 8 As shown, the specific implementation process of step S430 includes the following steps: Step S810: Determine that the disturbance direction of the current adjustment cycle is not the first direction.

[0060] Among them, step S710 and step S810 can be either parallel steps or progressive steps. That is, when step S810 and step S710 are parallel steps, if the current disturbance direction is not the first direction, then step S810 to step S830 are executed; if the current disturbance direction is the first direction, then step S710 is executed. When step S710 and step S810 are progressive steps, step S710 is executed first, and since the disturbance direction has been adjusted to not be the first direction, steps S810 to step S830 are then executed.

[0061] When it is determined that the disturbance direction of the current adjustment period is not the first direction, step S820 and step S830 are executed.

[0062] Step S820: If the average value of the output power in the current adjustment period is less than the recorded maximum power, or the current value of the output voltage of the power supply is less than the minimum value, the disturbance direction is adjusted to the first direction.

[0063] Specifically, by the fact that the average value of the output power of the current adjustment cycle is less than the recorded maximum power, it can be determined that when the disturbance direction is not the first direction, after the disturbance, the average value of the output power of the current adjustment cycle is reduced relative to the average value of the output power of the previous adjustment cycle. In this case, the disturbance direction should be adjusted from not being the first direction to the first direction, so as to expect that the average value of the output power of the next adjustment cycle increases relative to the average value of the output power of the current adjustment cycle, thereby approaching the target maximum power.

[0064] By the fact that the current value of the output voltage of the power supply 30 is less than the minimum value, it can be determined that when the disturbance direction is not the first direction, after the disturbance, the current value of the output voltage of the current cycle will be less than its minimum value, and the power supply 30 cannot provide voltage normally. At this time, the disturbance direction should be adjusted from not being the first direction to the first direction, so as to expect that the power supply 30 can provide voltage normally in the next adjustment cycle, thereby preventing the abnormal situation that the output voltage of the power supply 30 continues to be pulled down.

[0065] Step S830: If the average value of the output power of the current adjustment cycle is greater than or equal to the recorded maximum power, and the current value of the output voltage of the power supply is greater than or equal to the minimum value, the average value of the output power of the current adjustment cycle is recorded as the maximum power, and the first duty cycle is adjusted to the sum of the first duty cycle and the disturbance amount.

[0066] By the output voltage of the power supply 30 being greater than or equal to the minimum output voltage, it can be determined that the power supply 30 can maintain normal voltage supply. At the same time, by the average value of the output power of the current adjustment cycle being greater than or equal to the recorded maximum power, it can be determined that when the disturbance direction is not the first direction, after the disturbance, the average value of the output power of the current adjustment cycle is increased relative to the average value of the output power of the previous adjustment cycle. In this case, the disturbance direction should be kept unchanged, and the first duty cycle D1 should continue to be disturbed, that is, the first duty cycle D1 is adjusted to the sum of the first duty cycle D1 and the disturbance amount to approach the target maximum power.

[0067] In some embodiments, the absolute value of the disturbance amount is greater than the first preset increase value. Thus, after the charging device 10 starts to operate, the first duty cycle D1 is initially increased at a slower growth rate to prevent the abnormal situation that the output voltage of the photovoltaic module continues to decrease; thereafter, the first duty cycle D1 is disturbed at a faster disturbance rate to quickly approach the target maximum power.

[0068] In some embodiments, Fig. 9 As shown, after executing step S430, the duty cycle adjustment method further includes the following steps: Step S910: when the first duty cycle is greater than the maximum duty cycle, adjusting the disturbance direction to the first direction, and setting the first duty cycle to the maximum duty cycle.

[0069] Step S920: when the first duty cycle is smaller than the maximum duty cycle and the first duty cycle is smaller than the minimum duty cycle, adjusting the disturbance direction to the first direction and setting the first duty cycle to the minimum duty cycle.

[0070] Among them, the maximum duty cycle is the upper limit value of the preset duty cycle, and the minimum duty cycle is the lower limit value of the preset duty cycle. The two can be set based on the actual application scenario, and the minimum duty cycle is smaller than the maximum duty cycle. By setting the maximum duty cycle, it is possible to prevent the output voltage or current of the charging device 10 from exceeding the tolerable range due to the first duty cycle D1 being too high, thereby preventing the abnormal situation of the charging device 10 being damaged. By setting the minimum duty cycle, it is possible to prevent the charging device 10 from entering an undesirable working state (such as too low output power or too low efficiency, etc.), thereby ensuring that the charging device 10 operates within a safe and efficient range.

[0071] Specifically, if the first duty cycle D1 is greater than the maximum duty cycle, it is determined that the first duty cycle D1 of the current adjustment cycle is too large. At this time, the first duty cycle D1 is set to the maximum duty cycle. At the same time, the disturbance direction is adjusted to the first direction so that step S710 can be executed in the next adjustment cycle. According to the above description, it can be known that the target power maximum value can be re-approached by executing step S710. In summary, it is achieved that the first duty cycle D1 is adjusted to approach the target power maximum value under the premise of ensuring that the first duty cycle D1 is less than or equal to the maximum duty cycle.

[0072] If the first duty cycle D1 is less than the minimum duty cycle, it is determined that the first duty cycle D1 of the current adjustment cycle is too small. At this time, the first duty cycle D1 is set to the minimum duty cycle. At the same time, the disturbance direction is adjusted to the first direction so that step S710 can be performed in the next adjustment cycle to re-approach the target power maximum value. In summary, it is achieved that the duty cycle is adjusted to approach the target power maximum value under the premise of ensuring that the first duty cycle D1 is greater than the minimum duty cycle.

[0073] Afterwards, step S440 to step S450 are executed.

[0074] Step S440: generating a maximum output current of the charging device according to the output voltage of the charging device and the maximum output voltage of the charging device.

[0075] Step S450: generating a second duty cycle according to the maximum output current and the first output current of the charging device.

[0076] Specifically, according to step S440 and step S450, the constant voltage and current limiting functions can be realized.

[0077] In some embodiments, Fig.10 As shown, the specific implementation process of step S440 and step S450 includes the following steps: Step S1010: performing PI regulation on the difference between the output voltage of the charging device and the maximum output voltage to generate the maximum output current.

[0078] Step S1020: performing PI regulation on the difference between the maximum output current and the first output current to generate a second duty cycle.

[0079] The specific implementation process is as follows Fig.11 A PI adjustment is performed based on the difference VOUT_ER between the maximum output voltage VOUT_REF and the output voltage VOUT_FB of the charging device to obtain the maximum output current IOUT_REF, and then a PI adjustment is performed based on the difference IOUT_ER between the maximum output current IOUT_REF and the first output current IOUT_FB to obtain the second duty cycle D2.

[0080] In some embodiments, for Fig.11 The control method shown can also add a limiting unit to limit the corresponding parameters. For example, after performing PI adjustment on the difference VOUT_ER, the maximum output current IOUT_REF can be limited, and then the difference IOUT_ER between the limited maximum output current IOUT_REF and the first output current IOUT_FB can be PI adjusted.

[0081] Step S460: Determine a third duty cycle according to the minimum value of the adjusted first duty cycle and the second duty cycle, and set the first duty cycle as the third duty cycle.

[0082] Specifically, the adjusted first duty cycle D1 is the first duty cycle D1 after executing step S910 and step S920. The adjusted first duty cycle D1 is compared with the second duty cycle D2 to obtain the minimum value between the two, and the minimum value is the third duty cycle D3. The first duty cycle D1 is set to the third duty cycle D3, that is, the third duty cycle D3 is applied to the charging device 10, so that the charging device 10 has the functions of constant voltage, current limiting and tracking the maximum target power.

[0083] Understandably, if only Fig.11In the control method described above, when the photovoltaic energy is weak, the output current of the charging device 10 can never reach the maximum value, that is, the current IOUT_REF and the current IOUT_FB are always unequal, and the difference IOUT_ER always exists. Based on the PI regulation, the second duty cycle D2 will continue to increase in an attempt to increase the output current of the charging device 10. The output voltage of the charging device 10 will be continuously lowered accordingly, and may be lower than the minimum operating voltage of the charging device 10. The charging device 10 cannot work normally, and cannot track the maximum power of the photovoltaic module.

[0084] By adopting the control method provided by the present application, on the one hand, when the charging device 10 is loaded and operates normally, the second duty cycle D2 is usually greater than the adjusted first duty cycle D1, that is, the adjusted first duty cycle D1 is directly applied to the charging device 10, wherein, in the process of adjusting the first duty cycle D1, the first duty cycle D1 is pulled up at a slower growth rate at the beginning, so that the abnormal situation of the output voltage of the photovoltaic module continuously being pulled down will not occur, which is conducive to improving the stability of the operation of the photovoltaic module to provide stable power supply; thereafter, when the photovoltaic module is stably powered, the maximum power of the photovoltaic module can be more reliably tracked according to the output power and the disturbance direction. On the other hand, when the charging device 10 is loaded and an abnormality occurs, such as an abnormality such as an over-limit current, in this case, the second duty cycle D2 is usually smaller and smaller than the adjusted first duty cycle D1, so as to achieve the constant voltage and current limiting functions, so that the charging device 10 can maintain stable and reliable operation.

[0085] Please refer to Fig.12 , Fig.12 This is a flow chart of a duty cycle adjustment method provided by another embodiment of the present application. Fig.12 As shown, at the beginning of the adjustment cycle, it is determined whether the charging device 10 is loaded. When the charging device 10 is loaded, it is determined whether the target duty cycle has not been set. If the target duty cycle has not been set, the target duty cycle is determined according to 1 / K of the ratio of the output voltage of the charging device 10 to the input voltage of the charging device 10, and it is determined that the target duty cycle has been set. If the target duty cycle has been set, it is determined whether the preliminary adjustment process of the first duty cycle D1 is not completed.

[0086] If the preliminary adjustment process of the first duty cycle D1 is not completed, the process of gradually increasing the first duty cycle D1 is performed according to the target duty cycle and the output voltage of the power supply 30. The specific implementation process is as follows: First, it is determined whether the first duty cycle D1 is smaller than the target duty cycle, and whether the output voltage of the power supply 30 is greater than the minimum output voltage.

[0087] If the first duty cycle D1 is less than the target duty cycle, and the output voltage of the power supply 30 is greater than the minimum output voltage, the first duty cycle D1 is adjusted to be the sum of the first duty cycle D1 and the first preset increase value. Next, determine whether the average value of the output power of the current adjustment cycle is greater than the recorded maximum power. If the average value of the output power of the current adjustment cycle is greater than the recorded maximum power, the average value of the output power of the current adjustment cycle is recorded as the maximum power, and the adjusted first duty cycle D1 is recorded as the first duty cycle D1 corresponding to the maximum power, and the current adjustment cycle ends. If the average value of the output power of the current adjustment cycle is less than or equal to the recorded maximum power, the current adjustment cycle ends.

[0088] If the first duty cycle D1 is greater than or equal to the target duty cycle, and / or the output voltage of the power supply 30 is less than or equal to the minimum output voltage, it is determined that the preliminary adjustment process of the first duty cycle D1 has been completed, and the adjusted first duty cycle D1 is recorded as the first duty cycle D1 corresponding to the maximum power, and the current adjustment cycle ends.

[0089] If the preliminary adjustment process of the first duty cycle D1 is completed, the process of adjusting the first duty cycle D1 is performed according to the first output power and the disturbance direction when the first duty cycle D1 is disturbed. The specific implementation process is as follows: First, determine whether the disturbance direction of the current adjustment cycle is the first direction. If the disturbance direction of the current adjustment cycle is the first direction, the average value of the output power of the current adjustment cycle is recorded as the maximum power, and the direction of the disturbance amount that disturbs the first duty cycle D1 is adjusted to be reverse, and the disturbance direction is adjusted not to the first direction. If the disturbance direction of the current adjustment cycle is not the first direction, determine whether the average value of the output power of the current adjustment cycle is less than the recorded maximum power and determine whether the output voltage of the power supply 30 is less than the minimum output voltage. If the average value of the output power of the current adjustment cycle is less than the recorded maximum power, or the output voltage of the power supply 30 is less than the minimum output voltage, adjust the disturbance direction to the first direction. If the average value of the output power of the current adjustment cycle is greater than or equal to the recorded maximum power, and the output voltage of the power supply 30 is greater than or equal to the minimum output voltage, the average value of the output power of the current adjustment cycle is recorded as the maximum power, and the first duty cycle D1 is adjusted to be the sum of the first duty cycle D1 and the disturbance amount.

[0090] After that, it is determined whether the first duty cycle D1 is greater than the maximum duty cycle. If the first duty cycle D1 is greater than the maximum duty cycle, the perturbation direction is adjusted to the first direction, and the first duty cycle D1 is set to the maximum duty cycle, and the current adjustment period ends. If the first duty cycle D1 is less than or equal to the maximum duty cycle, it is further determined whether the first duty cycle D1 is less than the minimum duty cycle. If the first duty cycle D1 is less than the minimum duty cycle, the perturbation direction is adjusted to the first direction, and the first duty cycle D1 is set to the minimum duty cycle, and the current adjustment period ends. If the first duty cycle D1 is greater than or equal to the minimum duty cycle, the current adjustment period ends.

[0091] In summary, the first duty cycle D1 corresponding to the maximum power is obtained. In this process, after the start of the current adjustment period, first, according to the target duty cycle and the output voltage of the power supply 30, the first duty cycle D1 is adjusted to gradually increase. Then, by reducing the rate of increase of the first duty cycle D1, the first duty cycle D1 can be raised at a slower growth rate at the beginning. Thus, during the process of adjusting the first duty cycle D1, there will be no over-adjustment of the first duty cycle D1, so there will be no over-adjustment of the output voltage of the power supply 30, and there will be no abnormal situation where the output voltage of the power supply 30 is continuously pulled down. When the power supply 30 is a photovoltaic module, it is beneficial to improve the working stability of the photovoltaic module to stably supply power. Secondly, the target duty cycle can also be set according to experience to be close to the first duty cycle D1 corresponding to the target maximum power. Then, after the process of gradually increasing the first duty cycle D1 is completed, the first duty cycle D1 corresponding to the target maximum power can be quickly adjusted. Furthermore, in the subsequent adjustment process, by applying a perturbation amount to the first duty cycle D1 and adjusting the first duty cycle D1 in real time according to the perturbation direction and the output power of the power supply 30, the approximation of the target maximum power can be achieved, and the perturbation rate is fast and the adjustment time is short.

[0092] At the same time, for the charging device 10, a constant output voltage needs to be maintained and the maximum output current needs to be limited. Based on this, the charging device 10 also adopts Fig.11 the control method shown to obtain the second duty cycle D2 corresponding to the constant voltage and current limiting function, and the operation period for obtaining the second duty cycle D2 using this control method is Tn.

[0093] The operation period of the foregoing method for obtaining the first duty cycle D1 is Tm (i.e., the foregoing adjustment period), and Tm < Tn. After the two duty cycles are obtained, a comparison needs to be made, and the smaller of the two duty cycles is applied to the charging device 10. Thus, the charger 10 simultaneously has the functions of constant voltage and current limiting and tracking the maximum target power.

[0094] It should be noted that the steps shown as Figure 5-Figure 11 are all executed by the charging device 10.

[0095] In the above embodiments, all the method steps are performed when the charging device 10 is loaded. When the charging device 10 is not loaded (i.e., no-load), the charging device 10 only needs to maintain a constant output voltage and needs to limit the maximum output current. Based on this, when the charging device 10 is no-load, it can be used Fig.11 The control method shown is used to obtain the second duty cycle D2 of the first pulse width modulation signal. The second duty cycle D2 is applied to the charging device 10.

[0096] like Fig.13 As shown, the duty cycle adjustment method also includes the following steps: Step S1310: the energy storage device generates a disturbance signal corresponding to the maximum bus voltage.

[0097] Among them, the maximum bus voltage is the upper limit value of the preset bus voltage, which can be set based on the actual application scenario. The maximum bus voltage is determined according to the maximum input voltage allowed to be input by the energy storage device 20, and the maximum bus voltage can be set to be less than or equal to the maximum input voltage allowed to be input by the energy storage device 20. When the voltage input to the energy storage device 20 does not exceed the maximum input voltage, the energy storage device 20 will not be damaged by overvoltage, and irreversible damage to its internal circuits and other components can be avoided.

[0098] The disturbance signal corresponding to the maximum bus voltage means that the maximum bus voltage and the disturbance signal have a preset mapping relationship, and based on the maximum bus voltage and the mapping relationship, the disturbance signal corresponding to the maximum bus voltage can be obtained. Of course, if the disturbance signal is determined first, the maximum bus voltage corresponding to the disturbance signal can also be determined based on the disturbance signal and the mapping relationship.

[0099] In some embodiments, Fig.14 As shown, the specific implementation process of step S1310 includes the following steps: Step S1410: the energy storage device determines the frequency or peak value corresponding to the maximum bus voltage.

[0100] Specifically, the frequency (or peak value) corresponding to the maximum bus voltage means that the maximum bus voltage and the frequency (or peak value) have a preset mapping relationship, and based on the maximum bus voltage and the mapping relationship, the frequency (or peak value) corresponding to the maximum bus voltage can be obtained. Of course, if the frequency (or peak value) is determined first, the maximum bus voltage corresponding to the frequency (or peak value) can also be determined based on the frequency (or peak value) and the mapping relationship.

[0101] Step S1420: The energy storage device generates a disturbance signal according to the frequency or peak value.

[0102] In some embodiments, the specific implementation process of the energy storage device generating a disturbance signal according to the frequency is: the energy storage device generates the disturbance signal according to the product of the sine value corresponding to the frequency and the preset duty cycle.

[0103] The sine value corresponding to the frequency can be expressed as: sinθ, and θ=2π*Freq*T, where Freq is the frequency, T is the preset duration, and the preset duration can be determined based on the operation cycle when the energy storage device 20 performs the duty cycle adjustment method. For example, in a specific implementation, T is set to T=t*Ts, where Ts is the operation cycle and t is a coefficient greater than zero. Then, the disturbance signal is: DutyS*sinθ, where DutyS is the preset duty cycle.

[0104] In some embodiments, the preset duty cycle can be set by Fig.15 The steps shown are implemented. Fig.15 As shown, the duty cycle adjustment method also includes the following steps: Step S1510: the energy storage device determines the AC component according to the bus voltage.

[0105] Step S1520: The energy storage device determines a peak value according to the AC component.

[0106] The bus voltage in step S1510 refers to the bus voltage after the disturbance signal acts on the fourth duty cycle D4 of the second pulse width modulation signal, and the bus voltage at this time includes a DC component and an AC component.

[0107] Fig.16 The example shows a method in which the energy storage device determines the DC component, AC component, peak value and frequency according to the bus voltage. Fig.16As shown, the bus voltage VBUS is filtered by a low-pass filter unit to generate a DC component VBUS_DC; the difference between the bus voltage VBUS and the DC component VBUS_DC is calculated to obtain the AC component VBUS_AC; the AC component VBUS_AC is passed through a phase-locked loop based on a second-order generalized integrator to obtain the peak VBUS_A and the frequency VBUS_F. The second-order generalized integrator phase-locked loop (SOGI-PLL) is a phase-locked loop technology used in power systems and can be used to extract the frequency and peak value of the voltage. Among them, the second-order generalized integrator (SOGI) can decompose the input signal into an in-phase component and an orthogonal component. In the SOGI-PLL, the orthogonal signal generated by the SOGI is sent to the control part of the phase-locked loop (PLL). On the one hand, the control part can calculate the peak value obtained by the orthogonal signal; on the other hand, the control part uses a proportional integral (PI) controller to adjust the output of the local oscillator so that its frequency is synchronized with the voltage, thereby obtaining the frequency.

[0108] Step S1530: the energy storage device generates a preset duty cycle according to the maximum AC component and the peak value, so that the AC component is less than or equal to the maximum AC component.

[0109] The maximum AC component is the maximum value of the preset AC component, which can be set according to the actual application scenario. By controlling the actual value of the AC component to be less than or equal to the maximum AC component, it can be ensured that after the disturbance signal acts on the fourth duty cycle D4 of the second pulse width modulation signal, the change of the bus voltage is within an acceptable range (for example, the change will not cause damage to the energy storage device and the charging device), so as to ensure the stable operation of the energy storage device 20 and the charging device 10.

[0110] In a specific embodiment, the specific implementation steps of step S1530 are: the energy storage device performs PI adjustment on the difference between the maximum AC component and the peak value to generate a preset duty cycle. Through PI adjustment, the difference can be gradually reduced, and the preset duty cycle gradually increases. When the difference is reduced to 0, the preset duty cycle reaches the maximum value, and the peak value of the AC component is equal to the maximum AC component. It can be seen that the actual value of the AC component remains less than or equal to the maximum AC component, which is conducive to ensuring the stable operation of the energy storage device 20 and the charging device 10.

[0111] In some embodiments, after generating the preset duty cycle, the duty cycle adjustment method further includes the following steps: limiting the preset duty cycle. Then the specific implementation process of the energy storage device generating the disturbance signal according to the frequency is: the energy storage device generates the disturbance signal according to the product of the sine value corresponding to the frequency and the preset duty cycle after limiting.

[0112] Step S1320: the energy storage device applies the disturbance signal to the fourth duty cycle of the second pulse width modulation signal, so that the bus voltage includes a DC component and an AC component corresponding to the disturbance signal.

[0113] The fourth duty cycle D4 of the disturbance signal acting on the second pulse width modulation signal refers to combining the disturbance signal with the fourth duty cycle D4, and the specific combination method can be set according to the actual application scenario. And the fourth duty cycle D4 is updated according to the result of the combination, that is, the updated fourth duty cycle D4 is the result of the combination. The updated fourth duty cycle D4 is applied to the switch tube in the energy storage device 20, and then the bus voltage VBUS will include a DC component and an AC component corresponding to the disturbance signal.

[0114] In some embodiments, the duty cycle adjustment method further includes the following steps: the energy storage device performs PI adjustment on the difference between the preset given value of the bus voltage and the actual value of the bus voltage to generate the maximum value of the input current of the energy storage device; the energy storage device performs PI adjustment on the difference between the maximum value of the input current and the actual value of the input current to generate a fourth duty cycle of the second pulse width modulation signal. At the same time, the specific implementation process of step S1320 includes the following steps: the energy storage device superimposes the disturbance signal with the fourth duty cycle of the second pulse width modulation signal.

[0115] Fig.17 The control method of the energy storage device 20 is shown as an example. Fig.17 As shown, the energy storage device 20 performs PI regulation on the difference VIN_ER between the preset given value VIN_REF of the bus voltage and the actual value VIN_FB of the bus voltage to generate the maximum value IIN_REF of the input current of the energy storage device 20; the energy storage device 20 performs PI regulation on the difference IIN_ER between the maximum value IIN_REF of the input current and the actual value IIN_FB of the input current to generate the fourth duty cycle D4 of the second pulse width modulation signal.

[0116] At the same time, the energy storage device 20 performs PI regulation on the difference VD_ER between the preset maximum value VD_REF and the peak value VD_FB of the AC component to generate a preset duty cycle DutyS. According to the product of the sine value sinθ corresponding to the frequency and the preset duty cycle DutyS, a disturbance signal DutyS*sinθ is generated.

[0117] Finally, the fourth duty cycle D4 is superimposed on the disturbance signal DutyS*sinθ to generate a duty cycle DutyA. DutyA is the duty cycle of the updated second pulse width modulation signal. DutyA is applied to the switch tube in the energy storage device 20. After that, the bus voltage VBUS includes a DC component and an AC component corresponding to the disturbance signal.

[0118] In some embodiments, for Fig.17 In the control method shown, a limiting unit may be added to limit the corresponding parameters. For example, after the difference VIN_ER is PI-adjusted, the maximum value IIN_REF of the input current may be limited, and then the difference IIN_ER between the maximum value IIN_REF of the input current after limiting and the actual value IIN_FB of the input current may be PI-adjusted. For another example, after the difference IIN_ER is PI-adjusted, the fourth duty cycle D4 may be limited. For another example, after the fourth duty cycle D4 is superimposed with the disturbance signal DutyS*sinθ, the duty cycle DutyA may be limited, and then the limited duty cycle DutyA may be applied to the switch tube in the energy storage device 20.

[0119] Step S1330: The charging device determines the AC component according to the bus voltage.

[0120] The bus voltage here is a bus voltage including a DC component and an AC component corresponding to the disturbance signal. Since the charging device 10 is connected to the bus, the charging device 10 can obtain the bus voltage, and then obtain the AC component from the bus voltage.

[0121] In some embodiments, the specific implementation process of step S1330 includes the following steps: filtering the bus voltage to obtain a DC component; and determining an AC component based on the difference between the bus voltage and the DC component.

[0122] Specific examples include Fig.16 As shown, the bus voltage VBUS is filtered by a low-pass filtering unit to generate a DC component VBUS_DC; the difference between the bus voltage VBUS and the DC component VBUS_DC is calculated to obtain the AC component VBUS_AC.

[0123] Step S1340: the charging device controls the voltage output by the charging device according to the AC component, so that the voltage output by the charging device is less than or equal to the maximum bus voltage.

[0124] Specifically, since the AC component has a mapping relationship with the disturbance component, and the disturbance component has a mapping relationship with the maximum bus voltage, the AC component has a mapping relationship with the maximum bus voltage. Then, the charging device 10 determines the AC component, and accordingly determines the maximum bus voltage. On this basis, the charging device 10 can control its output voltage to be less than or equal to the maximum bus voltage. It can be seen that for different energy storage devices, the charging device can ensure that the output voltage does not exceed the maximum input voltage allowed by the energy storage device, so that the charging device can be compatible with different energy storage devices.

[0125] In some embodiments, Fig.18As shown, the specific implementation process of step S1340 includes the following steps: Step S1810: The charging device determines the frequency corresponding to the AC component according to the AC component.

[0126] Step S1820: The charging device determines the maximum bus voltage according to the frequency.

[0127] Step S1830: the charging device controls the second duty cycle according to the maximum bus voltage to control the voltage output by the charging device to be less than or equal to the maximum bus voltage.

[0128] For the embodiment in which the energy storage device generates a disturbance signal according to the product of the sine value corresponding to the frequency and the preset duty cycle, first, the Fig.16 In the manner shown, the AC component VBUS_AC is passed through a phase-locked loop based on a second-order generalized integrator to obtain a frequency VBUS_F; then, the maximum bus voltage corresponding to the frequency is determined according to the frequency and the mapping relationship (i.e., the mapping relationship between the maximum bus voltage and the frequency). On this basis, the charging device 10 can control the second duty cycle D2 according to the maximum bus voltage to control the voltage output by the charging device 10 to be less than or equal to the maximum bus voltage.

[0129] In some embodiments, Fig.19 As shown, the specific implementation process of step S1830 includes the following steps: Step S1910: The charging device performs PI regulation on the difference between the maximum bus voltage and the actual value of the bus voltage to generate the maximum output current of the charging device.

[0130] Step S1920: The charging device performs PI regulation on the difference between the maximum output current and the actual value of the output current to generate a second duty cycle.

[0131] Specific control process such as Fig.11 At this time, the maximum output voltage VOUT_REF corresponds to the maximum bus voltage, the output voltage VOUT_FB of the charging device corresponds to the actual value of the bus voltage, the maximum output current IOUT_REF corresponds to the maximum output current of the charging device, and the first output current IOUT_FB corresponds to the actual value of the output current.

[0132] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

[0133] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them. Under the idea of ​​the present application, the technical features in the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order. It should be understood by ordinary technicians in this field that they can still modify the technical solutions recorded in the above embodiments, or replace some of the technical features by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A duty cycle adjustment method, characterized in that: For adjusting a first duty cycle of a first pulse width modulation signal applied to a charging device, the charging device being connected to a power source, the method comprising: When determining that the charging device is loaded, perform the following steps: According to the target duty cycle and the output voltage of the power supply, adjusting the first duty cycle to gradually increase until the first duty cycle is greater than or equal to the target duty cycle and / or the output voltage of the power supply is less than or equal to the minimum output voltage of the power supply; adjusting the first duty cycle according to the output power of the power supply and the disturbance direction when the first duty cycle is disturbed, wherein when the average value of the output power in the current adjustment cycle decreases relative to the average value of the output power in the previous adjustment cycle, the disturbance direction is the first direction, and the duration of the adjustment cycle is the duration of adjusting the first duty cycle once; generating a maximum output current of the charging device according to the output voltage of the charging device and the maximum output voltage of the charging device; generating a second duty cycle according to the maximum output current and the first output current of the charging device; A third duty cycle is determined according to a minimum value between the adjusted first duty cycle and the second duty cycle, and the first duty cycle is set as the third duty cycle.

2. The method according to claim 1, characterized in that The step of adjusting the first duty cycle to gradually increase according to the target duty cycle and the output voltage of the power supply comprises: In each of the adjustment cycles, when the first duty cycle is less than the target duty cycle and the output voltage of the power supply is greater than the minimum output voltage, the first duty cycle is adjusted to be the sum of the first duty cycle and a first preset increase value, so as to adjust the first duty cycle to gradually increase.

3. The method according to claim 2, characterized in that After executing the step of adjusting the first duty cycle to the sum of the first duty cycle and a first preset increase value, the method further includes: When the average value of the output power in the current adjustment cycle is greater than the recorded maximum power, the average value of the output power in the current adjustment cycle is recorded as the maximum power, and the adjusted first duty cycle is recorded as the first duty cycle corresponding to the maximum power.

4. The method according to any one of claims 1 to 3, characterized in that: Before executing the step of adjusting the first duty cycle to gradually increase according to the target duty cycle and the output voltage of the power supply until the first duty cycle is greater than or equal to the target duty cycle and / or the output voltage of the power supply is less than or equal to the minimum output voltage of the power supply, the method further includes: determining whether a preliminary adjustment process of the first duty cycle has been completed; If not, the step of adjusting the first duty cycle to gradually increase according to the target duty cycle and the output voltage of the power supply is performed until the first duty cycle is greater than or equal to the target duty cycle and / or the output voltage of the power supply is less than or equal to the minimum output voltage of the power supply is performed; If yes, performing the step of adjusting the first duty cycle according to the output power of the power supply and the disturbance direction when the first duty cycle is disturbed; After executing the step of adjusting the first duty cycle to gradually increase according to the target duty cycle and the output voltage of the power supply until the first duty cycle is greater than or equal to the target duty cycle and / or the output voltage of the power supply is less than or equal to the minimum output voltage of the power supply, the method further includes: Determining that a preliminary adjustment process of the first duty cycle has been completed; The adjusted first duty cycle is recorded as the first duty cycle corresponding to the maximum power.

5. The method according to claim 1, characterized in that The method further comprises: The target duty cycle is determined according to 1 / K, which is a ratio of the output voltage of the charging device to the input voltage of the charging device, where K is greater than 0 and less than 1.

6. The method according to claim 1, characterized in that The step of adjusting the first duty cycle according to the output power of the power supply and the disturbance direction when the first duty cycle is disturbed includes: When it is determined that the disturbance direction of the current adjustment cycle is the first direction, the average value of the output power of the current adjustment cycle is recorded as the maximum power, and the direction of the disturbance amount for disturbing the first duty cycle is adjusted to the reverse direction, and the disturbance direction is adjusted not to the first direction.

7. The method according to claim 1 or 6, characterized in that: The step of adjusting the first duty cycle according to the output power of the power supply and the disturbance direction when the first duty cycle is disturbed includes: When it is determined that the disturbance direction of the current adjustment period is not the first direction, the following steps are performed: If the average value of the output power in the current adjustment cycle is less than the recorded maximum power, or the current value of the output voltage of the power supply is less than the minimum output voltage, then adjusting the disturbance direction to the first direction; If the average value of the output power in the current adjustment cycle is greater than or equal to the recorded maximum power, and the current value of the output voltage of the power supply is greater than or equal to the minimum output voltage, the average value of the output power in the current adjustment cycle is recorded as the maximum power, and the first duty cycle is adjusted to the sum of the first duty cycle and the disturbance amount.

8. The method according to claim 1, characterized in that After executing the step of adjusting the first duty cycle according to the output power of the power supply and the disturbance direction when the first duty cycle is disturbed, the method further includes: When the first duty cycle is greater than the maximum duty cycle, the disturbance direction is adjusted to the first direction, and the first duty cycle is set to the maximum duty cycle.

9. The method according to claim 1, characterized in that: After executing the step of adjusting the first duty cycle according to the output power of the power supply and the disturbance direction when the first duty cycle is disturbed, the method further includes: When the first duty cycle is smaller than the maximum duty cycle and the first duty cycle is smaller than the minimum duty cycle, the disturbance direction is adjusted to the first direction, and the first duty cycle is set to the minimum duty cycle.

10. The method according to claim 1, characterized in that The step of generating the maximum output current of the charging device according to the output voltage of the charging device and the maximum output voltage of the charging device comprises: performing PI regulation on a difference between an output voltage of the charging device and the maximum output voltage to generate the maximum output current; The step of generating a first duty cycle according to the maximum output current and the first output current of the charging device includes: A PI regulation is performed on a difference between the maximum output current and the first output current to generate the second duty cycle.

11. A charging device, characterized in that: include: A charging circuit connected to a power source and configured to output a bus voltage based on a voltage output by the power source; A first control unit, connected to the charging circuit, for adjusting a duty cycle of a first pulse width modulation signal applied to the charging device, comprising: at least one processor and memory; The memory is coupled to the processor, and the memory is used to store instructions or programs. When the instructions or programs are executed by the at least one processor, the at least one processor executes the duty cycle adjustment method as described in any one of claims 1-10.

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