Multi-peak maximum power searching method, power equipment and computer readable storage medium

Abstract

The invention relates to a multi-peak maximum power searching method. An initial global maximum power point is recorded in a default maximum power point tracking mode of a single-peak curve. And then determining whether a PV curve of the photovoltaic module has multi-peak output or not through comparison of input current, performing further power point search on a preset voltage region given by the input voltage to obtain a local maximum power point under the condition that the existence of the multi-peak output is determined, and finally determining a global maximum power point. Therefore, under the condition that multi-peak output occurs in the photovoltaic module, the scanning time of the output of the photovoltaic module is reduced, the global maximum power point of the output of the photovoltaic module is determined more quickly, and the power generation efficiency of the photovoltaic module is improved.

Description

Technical Field

[0001] The present application belongs to the field of power electronics technology, and in particular relates to a multi-peak maximum power search method, power equipment, and computer-readable storage medium. Background Art

[0002] Photovoltaic (PV) arrays are often susceptible to uneven sunlight due to obstruction by buildings, trees, and clouds. Furthermore, PV cell aging and component damage can also be attributed to uneven sunlight. Uneven sunlight directly alters the output characteristics of the PV array, causing its PV curve (voltage-power curve) to exhibit multiple peaks. This renders traditional maximum power point tracking (MPPT) methods ineffective, leading to a significant drop in PV array output power, reduced power generation efficiency, and severe power loss. This also increases the difficulty of fault detection. Summary of the Invention

[0003] The purpose of this application is to provide a multi-peak maximum power search method, power equipment and computer-readable storage medium, aiming to solve the problem that the traditional maximum power point tracking method fails when the photovoltaic module has multi-peak output.

[0004] In a first aspect, an embodiment of the present application provides a multi-peak maximum power search method, comprising:

[0005] Setting the input voltage setting of the photovoltaic module to a first input voltage setting, and gradually increasing the input current setting limit to a preset maximum input current to search for an initial global maximum power point; wherein the first input voltage setting is less than the open-circuit voltage of the photovoltaic module;

[0006] Obtaining a first input current corresponding to the first input voltage;

[0007] Setting the input voltage given as a second input voltage given, and obtaining a second input current corresponding to the second input voltage given, wherein the second input voltage given is less than the first input voltage given;

[0008] When the difference between the second input current and the first input current is greater than or equal to a preset difference, adjusting the input voltage setting by a preset voltage adjustment step size within a preset voltage range to perform power search and obtain a local maximum power point, wherein the first input voltage setting and the second input voltage setting are within the preset voltage range;

[0009] A global maximum power point is determined according to the initial global maximum power point and the local maximum power point.

[0010] In one embodiment, after setting the input voltage reference to a second input voltage reference and obtaining a second input current corresponding to the second input voltage reference, the method further includes:

[0011] When the difference between the second input current and the first input current is smaller than a preset difference, the initial global maximum power point is determined to be the current global maximum power point.

[0012] In one embodiment, a lower limit value of the preset voltage range is less than or equal to the second input voltage setting, and an upper limit value of the preset voltage range is greater than the first input voltage setting.

[0013] In one embodiment, the step of adjusting the input voltage within the preset voltage region with a preset voltage adjustment step to perform power search and obtain a local maximum power point includes:

[0014] Setting the input voltage to the lower limit of the preset voltage range, and gradually increasing it with the preset voltage adjustment step size until it reaches the upper limit of the preset voltage range, and determining the maximum input power of the photovoltaic module during the input voltage adjustment process as the local maximum power point; or

[0015] The initial value of the given input voltage is set as the upper limit value of the preset voltage range, and the preset voltage adjustment step is gradually reduced to the lower limit value of the preset voltage range, and the maximum power point searched during the given input voltage adjustment process is determined as the local maximum power point.

[0016] In one embodiment, the first input voltage is set between 75% and 85% of the open circuit voltage, and the second input voltage is set between 40% and 50% of the open circuit voltage.

[0017] In one embodiment, the step of gradually increasing the input current limit to a preset maximum input current to search for an initial global maximum power point includes:

[0018] performing a limiting process on the output of the input voltage loop of the photovoltaic module to obtain the input current setting;

[0019] The amplitude limiting value of the amplitude limiting process is gradually increased from 0 to the preset maximum input current.

[0020] In one embodiment, determining the global maximum power point according to the initial global maximum power point and the local maximum power point includes:

[0021] A larger value between the initial global maximum power point and the local maximum power point is determined as the global maximum power point.

[0022] In one embodiment, the method further comprises:

[0023] After determining the global maximum power point, the input voltage is set to a voltage value corresponding to the global maximum power point, and a preset maximum power tracking algorithm is executed.

[0024] In a second aspect, an embodiment of the present application further provides an electric power device, comprising a DC converter, a memory, a processor, and a computer program stored in the memory and runnable on the processor, wherein the DC converter comprises a first end and a second end, the first end being used to connect a photovoltaic component, the second end being used to connect a DC bus, the DC bus being used to connect one or more of a battery module, a load, and an inverter, and the processor implementing the steps of the multi-peak maximum power search method described above when executing the computer program.

[0025] In a third aspect, an embodiment of the present application further provides a computer-readable storage medium, which stores a computer program, and when the computer program is executed by a controller, the steps of the above method can be implemented.

[0026] Compared with the related art, the embodiments of the present application have the following advantages: first, power statistics are performed based on a first input voltage setting less than an open circuit and gradually releasing the input current setting from the limit to a preset maximum input current to obtain an initial global maximum power point; then, the input voltage setting is set to a second output voltage setting less than the first input voltage setting and the second input current at this time is obtained; when the difference between the second input current and the first input current corresponding to the first input voltage setting is greater than or equal to the preset difference, it indicates that there is a significant current fluctuation to the left of the initial global maximum power point, which conforms to the characteristics of a multi-peak curve; at this time, the input voltage setting is adjusted within the preset voltage region of the photovoltaic module to search for a multi-peak power point, obtain a local maximum power point, and finally determine the global maximum power point based on the magnitude of the initial global maximum power point and the local maximum power point. In this way, when the photovoltaic module has multi-peak output, the scanning time of the photovoltaic module output can be reduced, the global maximum power point of the photovoltaic module output can be determined more quickly, and the power generation efficiency of the photovoltaic module can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of a single-peak PV curve output by a photovoltaic module according to an embodiment of the present application;

[0028] Figure 2 A schematic diagram of a multi-peak PV curve output by a photovoltaic module according to an embodiment of the present application;

[0029] Figure 3A block diagram of the MPPT circuit provided in one embodiment of the present application;

[0030] Figure 4 A flowchart of a multi-peak maximum power search method provided in one embodiment of the present application;

[0031] Figure 5 A schematic diagram of a multi-peak IV curve output by a photovoltaic module according to an embodiment of the present application;

[0032] Figure 6 A schematic diagram of a multi-peak PV curve output by a photovoltaic module according to an embodiment of the present application;

[0033] Figure 7 A schematic diagram of a single-peak IV curve output by a photovoltaic module according to an embodiment of the present application;

[0034] Figure 8 A schematic diagram of a single-peak PV curve output by a photovoltaic module according to an embodiment of the present application;

[0035] Figure 9 Schematic diagram of multi-peak IV curve and multi-peak PV curve output by a photovoltaic module provided in one embodiment of the present application;

[0036] Figure 10 A schematic diagram of a voltage curve for a multi-peak maximum power search according to an embodiment of the present application;

[0037] Figure 11 Schematic diagram of a single-peak IV curve and a single-peak PV curve output by a photovoltaic module provided in one embodiment of the present application;

[0038] Figure 12 A schematic diagram of a multi-peak maximum power search curve provided in an embodiment of the present application;

[0039] Figure 13 A structural block diagram of a multi-peak maximum power search device provided in one embodiment of the present application;

[0040] Figure 14 A schematic diagram of the structure of an electric power device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0041] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0042] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0043] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0044] The following will describe some embodiments with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features therein may be combined with each other.

[0045] With the development of solar photovoltaic technology, photovoltaic systems are widely used in scenarios such as home energy storage. The power of photovoltaic modules (i.e., photovoltaic cell arrays) varies with factors such as sunlight conditions. Therefore, by tracking the peak power of photovoltaic modules, it is possible to ensure that the modules output at maximum power.

[0046] However, due to differences in the location of PV panels in different households, the sunlight conditions in the installation area, and factors such as shadows, aging PV panels, and unclean panels, the PV curve of PV panels often has multiple peaks. This renders traditional maximum power point tracking (MPPT) methods ineffective, causing a significant drop in PV output power, resulting in severe power loss, reduced power generation efficiency, increased power generation costs, and increased difficulty in fault detection.

[0047] For example, see Figure 1 When the sunlight intensity and operating temperature are constant, the PV curve of the photovoltaic module shows a single peak phenomenon. When the light intensity is unstable or the photovoltaic module is partially shaded, please refer to Figure 2 , the PV curve of the photovoltaic module will show multiple peaks. For multi-peak curves, traditional maximum power point tracking algorithms are prone to violent fluctuations during the tracking process of the maximum power point. They are also prone to stopping tracking at the local optimum, becoming trapped in the local optimum and unable to accurately determine the true maximum power point, resulting in low power generation efficiency of the photovoltaic module.

[0048] Based on this, the present application provides a multi-peak maximum power search method, which can effectively determine the global maximum power point even when a photovoltaic module has a multi-peak curve.

[0049] It is understandable that the multi-peak maximum power search method provided by the present application can be applied to an MPPT circuit or an electronic device provided with an MPPT circuit. For example, see Figure 3 , Figure 3 1 is a structural block diagram of an MPPT circuit 10 that applies the multi-peak maximum power search method provided in an embodiment of the present application.

[0050] like Figure 3 As shown, the photovoltaic module 20 and the load 30 are connected via an MPPT circuit 10. The MPPT circuit 10 includes a DC / DC converter unit 110, a processor 120, and a pulse width modulation (PWM) controller 130. The processor 120 continuously detects changes in the current or voltage of the photovoltaic module 20 and outputs a control signal to the PWM controller 130 based on the changes. The PWM controller 130 adjusts the duty cycle of the PWM signal of the DC / DC converter unit 110, thereby adjusting the input voltage of the DC / DC converter unit 110 (i.e., the output voltage of the photovoltaic module 20). Since the photovoltaic module 20 and the DC / DC converter unit 110 can be considered as linear circuits in a short period of time, as long as the equivalent resistance of the DC / DC converter unit 110 is always equal to the internal resistance of the photovoltaic module 20 while adjusting the input voltage of the DC / DC converter unit 110, the maximum output of the photovoltaic module 20 can be achieved, thus realizing the MPPT function of the photovoltaic module 20. The DC / DC conversion unit 110 may be composed of a buck circuit, a boost circuit, or a buck-boost circuit, which is not limited in this application.

[0051] The photovoltaic assembly 20 includes a photovoltaic cell array. The photovoltaic cell array converts light energy into electrical energy to output direct current to the MPPT circuit 10. It is understandable that the present application does not limit the connection method of the photovoltaic cell array in the photovoltaic assembly 20. For example, in some embodiments, the photovoltaic cell array in the photovoltaic assembly 20 can be connected in series, in parallel, or first in series and then in parallel. The load 30 can be various types of DC power loads. In some embodiments, the MPPT circuit 10 or the load 30 further includes an AC / DC conversion unit, which is connected between the DC / DC conversion unit 110 and the AC load, thereby converting the DC power output by the DC / DC conversion unit into AC / DC and outputting AC power to power the AC load.

[0052] In some embodiments, the PWM controller 130 and the processor 120 are independently configured. In some embodiments, the PWM controller 130 may also be integrated into the processor 120.

[0053] See also Figure 4 , Figure 4 This is a flow chart of a multi-peak maximum power search method provided in one embodiment of the present application. It is understandable that the multi-peak maximum power search method can be executed by the processor 120 in the MPPT circuit 10. The multi-peak maximum power search method includes the following steps:

[0054] In step S110 , the input voltage setting of the photovoltaic module is set to a first input voltage setting, and the input current setting limit is gradually increased to a preset maximum input current to search for an initial global maximum power point; wherein the first input voltage setting is less than the open circuit voltage of the photovoltaic module.

[0055] Please refer to Figure 5 、 Figure 6 、 Figure 7 as well as Figure 8 . Figure 5 FIG. 1 is a schematic diagram of a multi-peak IV curve (current-voltage curve) of a photovoltaic module in one embodiment of the present application. Figure 6 Shown Figure 5 Schematic diagram of the multi-peak PV curve corresponding to the IV curve shown. Figure 7 FIG. 1 is a schematic diagram of a single-peak IV curve (current-voltage curve) of a photovoltaic module in an embodiment of the present application. Figure 8 Shown Figure 7 Schematic diagram of the multi-peak PV curve corresponding to the IV curve shown.

[0056] from Figure 5 and Figure 6 It can be seen that when the PV curve is a multi-peak curve, the multi-peak IV curve always presents a step-like decreasing trend. Figure 7 and Figure 8 It can be seen that when the PV curve is unimodal, the unimodal IV curve does not exhibit this phenomenon. For example, analyzing a common monocrystalline silicon photovoltaic module, its FF (fill factor) is typically around 0.8. FF is defined as FF = (Vmp * Imp) / (Voc * Isc), where Vmp and Imp are the maximum power point voltage and maximum power point current of the photovoltaic module 20, respectively; Voc and Isc are the open-circuit voltage and short-circuit current of the photovoltaic module, respectively. Therefore, for a unimodal curve, the maximum power point of the photovoltaic module is typically around 80% * Voc.

[0057] Therefore, in this step, as can be seen from the step-wise decrease of the multi-peak curve, when searching / tracking from the right side of the multi-peak curve (i.e., near the open circuit), the first input voltage setting can be set to 75% to 85% of the open-circuit voltage (i.e., 75% * Voc to 85% * Voc), based on the default characteristic that the maximum power point of the single-peak curve is near 80% * Voc. On this basis, the input current setting limit is gradually increased to the preset maximum input current, and power statistics are performed to record the initial global maximum power point P1.

[0058] In this step, the upper limit of the input current is determined by the DC / DC conversion unit 110 , and the preset maximum input current may be the maximum current value that the DC / DC conversion unit 110 can support.

[0059] Step S120 , obtaining a first input current corresponding to a given first input voltage.

[0060] It can be understood that the first input current corresponding to the first input voltage setting refers to the input current of the photovoltaic module 20 after the loop stabilizes after the input current setting value is increased to the preset maximum input current. It can also be understood as the input current of the photovoltaic module 20 at the initial global maximum power P1. Here, loop stability means that the actual output voltage of the DC / DC converter unit 110 of the photovoltaic module 20 is stable at the first input voltage setting.

[0061] Comparison Figure 5 and Figure 7 It can be seen that the current of the multi-peak IV curve shows a step-like decreasing trend, and the current of the single-peak IV curve shows a decreasing trend only on the right side of the global maximum power point, and the current on the left side of the global maximum power point tends to be stable. Therefore, by obtaining the first input current corresponding to the first input voltage, and then comparing the input current corresponding to when the output voltage of the photovoltaic component 20 is less than the first input voltage with the first input current, it can be preliminarily determined whether the PV curve of the photovoltaic component 20 has multiple peaks.

[0062] Step S130: setting the input voltage reference to a second input voltage reference, and obtaining a second input current corresponding to the second input voltage reference, wherein the second input voltage reference is smaller than the first input voltage reference.

[0063] It can be understood that the second input current corresponding to the second input voltage setting also refers to the input current of the photovoltaic component 20 after the loop is stabilized after the input voltage setting is set to the second input voltage setting.

[0064] After completing the recording of the initial global maximum power point P1, it can be confirmed whether there is a power point larger than the initial global maximum power point P1 by searching to the left, where the left refers to a direction in the PV curve that is smaller than the first input voltage given, that is, the input voltage given is set to be smaller than the first input voltage given.

[0065] Taking the bimodal curve as an example, when the number of photovoltaic modules 20 that are blocked reaches about half of the total number, the global maximum power point is at 50% of the open-circuit voltage. Assuming that the number of blocked photovoltaic modules 20 reaches half of the total number, which is the lowest available condition, and taking into account a certain margin, the left search only needs to use about half of the open-circuit voltage of the photovoltaic modules 20 as the boundary value, and any value between this boundary value and the first input voltage setting is taken as the second input voltage setting. Exemplarily, the boundary value is directly taken as the second input voltage setting, for example, the second input voltage setting is set between 40% and 50% of the open-circuit voltage, and a typical value is 45%*Voc. In other examples, depending on the environmental conditions of the photovoltaic modules 20, the second input voltage setting can be set to a lower value than 45%*Voc, or a higher value than 45%*Voc.

[0066] The acquired second input voltage is given a corresponding second input current for comparison with the first input current to determine whether the PV curve of the photovoltaic assembly 20 has multiple peaks.

[0067] Step S140, when the difference between the second input current and the first input current is greater than or equal to the preset difference, the input voltage is adjusted within a preset voltage range with a preset voltage adjustment step to perform a power search and obtain a local maximum power point, wherein the first input voltage and the second input voltage are within the preset voltage range.

[0068] For example, the preset difference can be set to any value between 10%*Imp and 30%*Imp; typically, it is set to 20%*Imp. Figure 5 and Figure 6 The PV curve of the photovoltaic module 20 has multiple peaks, and the current at 45%*Voc is much larger than 20%*Imp. Therefore, when the difference between the second input current and the first input current is greater than or equal to the preset difference, it can be considered that the PV curve of the photovoltaic module 20 has multiple peaks; conversely, when the difference between the second input current and the first input current is less than the preset difference, it is considered that the PV curve of the photovoltaic module 20 does not have multiple peaks.

[0069] In addition, the voltage adjustment step size is used to represent the voltage change step size of the input voltage of the DC / DC converter unit 110 compared to the initial global maximum power point. It is understood that the upper and lower limits of the preset voltage range are set according to the total proportion of the number of photovoltaic components 20 that are shaded under normal circumstances.

[0070] The power points of the MPPT circuit 10's input voltage reference during its change between the upper limit and the lower limit of the preset voltage range are continuously recorded, and the local maximum power point P2 is obtained when the steady state is reached. Specifically, the input voltage reference can be gradually adjusted from the upper limit of the preset voltage range to the upper limit with a preset voltage adjustment step size, or the input voltage reference can be gradually adjusted from the upper limit of the preset voltage range to the upper limit with a preset voltage adjustment step size, and each power point that jumps during the adjustment process is recorded, and finally the local maximum power point P2 is obtained.

[0071] Step S150 : determining a global maximum power point according to the initial global maximum power point and the local power points.

[0072] From the initial global maximum power point P1 and the local maximum power point P2, the larger power point is selected as the global maximum power point.

[0073] Based on the above-described multi-peak maximum power search method, for PV curves of PV modules 20 with multi-peak outputs, the location of their global maximum power point is not fixed due to varying shade conditions and variations in illumination under shade, and is typically subject to dynamic change. Therefore, an initial global maximum power point (P1) is recorded starting at the default maximum power point voltage of the single-peak curve. Subsequently, the presence of multi-peak output in the PV curve of the PV module 20 is confirmed by comparing the input current. If multi-peak output is confirmed, a further power point search is performed within a preset voltage region within the input voltage to obtain local maximum power points, and finally, the global maximum power point is determined. This reduces the scanning time for the PV module output when the PV module 20 exhibits multi-peak output, allowing for faster determination of the global maximum power point of the PV module output and improving the PV module's power generation efficiency.

[0074] In one embodiment, after step S130 , the method further includes: when the difference between the second input current and the first input current is less than a preset difference, determining the initial global maximum power point as the current global maximum power point.

[0075] As mentioned above, when the difference between the second input current and the first input current is less than the preset difference, it is considered that the PV curve of the photovoltaic component 20 does not have a multi-peak output, that is, the PV curve of the photovoltaic component 20 is a single-peak curve. Therefore, the initial global maximum power point P1 can be directly determined as the current global maximum power point, thereby saving computing resources.

[0076] In one embodiment, a lower limit value of the preset voltage region is less than or equal to the second given input voltage, and an upper limit value of the preset voltage region is greater than the first given input voltage.

[0077] In some scenarios, assuming that half of the total number of shaded photovoltaic modules 20 is the lowest available, the corresponding global maximum power point is approximately at 50%*Voc. Therefore, taking into account a certain margin, the lower limit of the preset voltage range can be set to 45%*Voc, and the value range of the second input voltage setting is between the lower limit of the preset voltage range and the first input voltage setting. In order to accurately confirm whether there are multiple peaks, the second input voltage setting can be directly set to the lower limit of the preset voltage range or close to the lower limit of the preset voltage range. Similarly, the upper limit of the preset voltage range is set to be greater than the first input voltage setting, so that the presence of multiple peaks can be accurately confirmed.

[0078] In one embodiment, the step S140 of adjusting the input voltage within a preset voltage range with a preset voltage adjustment step size to perform power search and obtaining the local maximum power point includes:

[0079] Setting the input voltage to the lower limit of a preset voltage range and gradually increasing it with a preset voltage adjustment step size until it reaches the upper limit of the preset voltage range, and determining the maximum input power of the photovoltaic module during the input voltage adjustment process as the local maximum power point; or

[0080] The initial value of the input voltage is set as the upper limit value of the preset voltage range, and is gradually reduced to the lower limit value of the preset voltage range with a preset voltage adjustment step size, and the maximum power point searched during the input voltage adjustment process is determined as the local maximum power point.

[0081] This embodiment provides two different methods for searching the local maximum power point P2: one method searches from the lower limit of the preset voltage range toward the upper limit of the preset voltage range, and the other method searches in the opposite direction. In other embodiments, other search methods may be used, such as searching from the middle of the preset voltage range toward both ends simultaneously.

[0082] In one embodiment, in step S110, gradually increasing the input current limit to a preset maximum input current to search for an initial global maximum power point includes:

[0083] The output of the input voltage loop of the photovoltaic module is limited to obtain the input current setting.

[0084] The limit value of the limit processing is gradually increased from 0 to the preset maximum input current.

[0085] The preset maximum input current can be arbitrarily set according to the rated input current of the DC / DC conversion unit 110. Gradually increasing the limit value of the limit process from 0 to the preset maximum input current is a process of searching for the initial global maximum power point P1.

[0086] For example, see Figure 9 and Figure 10 , Figure 9 The figure shows a schematic diagram of a multi-peak PV curve and an IV curve output by a photovoltaic module in one embodiment. Figure 10 Shown for Figure 9 The voltage variation diagram shown in the multi-peak curve during the multi-peak maximum power search is shown. Taking an open-circuit voltage of 172V as an example, the input voltage is first set to Voc*0.8=172V*0.8=137.6V (i.e., the first input voltage setting). Then, the limit value of the input voltage loop output is gradually increased (i.e., the limit value of the limit processing is gradually increased from 0 to the preset maximum input current). In this process, the power at 165V (120W) is found as the initial global maximum power point P1. Next, set the input voltage to 0.45*Voc, i.e., the second input voltage setting: 172V*0.45=77.4V. The current at 77.4V is 2.3A, which is 1.2 times greater than the current at Voc*0.8, i.e., 0.7A*1.2. Therefore, it can be assumed that the output of photovoltaic module 20 has multiple peaks between Voc*0.45 and Voc*0.8. At this point, gradually increase the input voltage from Voc*0.45 to Voc*0.85, and record the input power during this process. It is not difficult to find that the power at 123V is the local maximum power P2 of this segment, which is 123V*2.28A=282W. Comparing the initial global maximum power point P1 at 165V with the local maximum power P2 at 123V, it can be determined that the global maximum power in the global state occurs when the input voltage is 123V, completing the multi-peak search process.

[0087] For example, see Figure 11 and Figure 12 , Figure 11 FIG. 1 is a schematic diagram of a single-peak PV curve and an IV curve output by a photovoltaic module in one embodiment. Figure 10 Shown for Figure 9The voltage change diagram shown in the single-peak curve during the multi-peak maximum power search is shown. Taking an open-circuit voltage of 183V as an example, the input voltage is first set to Voc*0.8=183V*0.8=147V (i.e., the first input voltage setting). Then, the limit value of the input voltage loop output is gradually increased. In this process, the power at 147V (1064.88W) is found as the initial global maximum power point P1. Next, the input voltage setting is set to 0.45*Voc, i.e., the second input voltage setting is: 183V*0.45=82.35V. The current at 82.35V is 7.9A, which is less than the 7.33A*1.2 at Voc*0.8. It is assumed that the output of the photovoltaic module 20 does not have multiple peaks between Voc*0.45 and Voc*0.8. The initial global maximum power point P1 found is the global maximum power in the global state, and the entire multi-peak search process is completed.

[0088] In one embodiment, step S150 includes: determining the larger value of the initial global maximum power point and the local power point as the global maximum power point. Determining the power point with the larger value as the global maximum power point can improve power generation efficiency.

[0089] In one embodiment, after step S150 , after determining the global maximum power point, the input voltage is set to a voltage value corresponding to the global maximum power point, and a preset maximum power point tracking algorithm is executed.

[0090] It is understood that the preset maximum power point tracking algorithm can be any conventional MPPT tracking algorithm in the related art, such as the perturbation and observation method, the incremental conductance method, the constant voltage tracking method, etc., and this application does not limit this. Taking the perturbation and observation method as an example, after determining the global maximum power point, the voltage value corresponding to the global maximum power point is used as the input voltage given as the initial value of the maximum power point tracking algorithm. Perturbation observation is performed within a conventional perturbation step size, and the global maximum power point is quickly updated when the light changes, so that the MPPT circuit can always operate under high power generation efficiency conditions.

[0091] It is understood that the multi-peak maximum power search method provided in this application can be executed after each startup of the photovoltaic module, or can be executed periodically thereafter to quickly find the global maximum power point under the multi-peak curve when uneven illumination occurs. Each time the global maximum power point is updated, a conventional preset maximum power tracking algorithm is executed to achieve real-time maximum power tracking.

[0092] See also Figure 13 , an embodiment of the present application further provides a multi-peak maximum power search device, comprising:

[0093] An initial search unit 131 is configured to set the input voltage setting of the photovoltaic module to a first input voltage setting, and gradually increase the limit of the input current setting to a preset maximum input current to search for an initial global maximum power point; wherein the first input voltage setting is less than the open-circuit voltage of the photovoltaic module;

[0094] A first acquiring unit 132 is configured to acquire a first input current corresponding to the first input voltage;

[0095] A second acquiring unit 133 is configured to set the input voltage setting to a second input voltage setting, and acquire a second input current corresponding to the second input voltage setting, wherein the second input voltage setting is smaller than the first input voltage setting;

[0096] a local search unit 134 configured to, when a difference between the second input current and the first input current is greater than or equal to a preset difference, adjust the input voltage setting by a preset voltage adjustment step size within a preset voltage range to perform a power search and obtain a local maximum power point, wherein the first input voltage setting and the second input voltage setting are within the preset voltage range;

[0097] The determining unit 135 is configured to determine a global maximum power point according to the initial global maximum power point and the local maximum power point.

[0098] In some embodiments, the determining unit 135 is further configured to determine the initial global maximum power point as the current global maximum power point when the difference between the second input current and the first input current is less than a preset difference.

[0099] In some embodiments, an upper limit value of the voltage region is greater than the first input voltage.

[0100] In some embodiments, the local search unit 134 includes:

[0101] a first search module, configured to set the input voltage to a lower limit of the preset voltage range, gradually increase the input voltage with the preset voltage adjustment step size until it reaches an upper limit of the preset voltage range, and determine the maximum input power of the photovoltaic module during the input voltage adjustment process as a local maximum power point;

[0102] The second search module is used to set the initial value of the given input voltage as the upper limit value of the preset voltage range, and gradually reduce the preset voltage adjustment step to the lower limit value of the preset voltage range, and determine the maximum power point searched during the given input voltage adjustment process as the local maximum power point.

[0103] In some embodiments, the first input voltage is set between 75% and 85% of the open circuit voltage, and the second input voltage is set between 40% and 50% of the open circuit voltage.

[0104] In some embodiments, the initial search unit 131 includes:

[0105] The amplitude limiting module is used to perform amplitude limiting processing on the output of the input voltage loop of the photovoltaic component to obtain the input current setting; and gradually increase the amplitude limiting value of the amplitude limiting processing from 0 to the preset maximum input current.

[0106] In some embodiments, the determining unit 135 is specifically configured to: determine a larger value between the initial global maximum power point and the local maximum power point as the global maximum power point.

[0107] In some embodiments, an execution unit is further included, which is used to set the input voltage to a voltage value corresponding to the global maximum power point after determining the global maximum power point, and execute a preset maximum power tracking algorithm.

[0108] For the specific implementation of the multi-peak maximum power search device and the description of related beneficial effects, please refer to the description of the specific embodiment of the multi-peak maximum power search method mentioned above, which will not be repeated here.

[0109] See also Figure 3 and 14 An embodiment of the present application further provides an electric power device 100 including a DC converter (i.e., a DC / DC conversion unit) 110, a memory 102, a processor 120, and a computer program 103 stored in the memory 102 and executable on the processor 120. The DC converter 110 includes a first end and a second end, the first end being used to connect to a photovoltaic component 20, and the second end being used to connect to a DC bus, the DC bus being used for one or more of a battery module, a load 30, and an inverter. The DC converter 110 is also connected to the processor 120. When the processor 120 executes the computer program 103, the steps of the multi-peak maximum power search method described above are implemented.

[0110] It is understandable that the power device 100 may be a separate power device, or may be a battery pack having battery modules, or an energy storage device including a plurality of battery packs having battery modules.

[0111] Those skilled in the art will understand that Figure 14 This is merely an example of the power device 100 and does not constitute a limitation on the power device 100 . The power device 100 may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, it may also include input and output devices, network access devices, etc.

[0112] The processor 120 may be a central processing unit (CPU), or may be other general-purpose controllers, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The general-purpose controller may be a microcontroller or any conventional controller.

[0113] In some embodiments, the memory 102 may be an internal storage unit of the power device 100 or the energy storage device, such as a hard disk or memory of the power device 100 or the energy storage device. In other embodiments, the memory 102 may also be an external storage device of the power device 100 or the energy storage device, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. equipped on the power device 100 or the energy storage device. Furthermore, the memory 102 may also include both an internal storage unit of the power device 100 or the energy storage device and an external storage device. The memory 102 is used to store an operating system, an application program, a boot loader (Boot Loader), data, and other programs. The memory 102 may also be used to temporarily store data that has been output or is to be output.

[0114] The embodiment of the present application further provides a computer-readable storage medium, which stores a computer program 103. When the computer program 103 is executed by the processor 120, it can implement the steps in the above-mentioned various method embodiments.

[0115] An embodiment of the present application provides a computer program product, which, when executed on a computer, enables the computer to execute the steps in the above-mentioned various method embodiments.

[0116] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application can implement all or part of the processes in the above-mentioned method embodiments by using computer program 103 to instruct the relevant hardware. The computer program 103 can be stored in a computer-readable storage medium. When executed by processor 120, the computer program 103 can implement the steps of each of the above-mentioned method embodiments. The computer program 103 includes computer program 103 code, which can be in source code form, object code form, executable file, or some intermediate form. The computer-readable medium can at least include: any entity or device capable of carrying the computer program 103 code to the camera / terminal device, a recording medium, computer memory 102, ROM (Read-Only Memory), RAM (Random Access Memory), CD-ROM (Compact Disc Read-Only Memory), magnetic tape, floppy disk, and optical data storage device. The computer-readable storage medium mentioned in this application may be a non-volatile storage medium, in other words, a non-transitory storage medium.

[0117] It should be understood that all or part of the steps for implementing the above embodiments may be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the steps may be implemented in the form of a computer program 103 product. The computer program 103 product includes one or more computer instructions. The computer instructions may be stored in the computer-readable storage medium described above.

[0118] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0119] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0120] In the embodiments provided in this application, it should be understood that the disclosed devices / electronic devices and methods can be implemented in other ways. For example, the device / electronic device embodiments described above are merely schematic. For example, the division of modules or units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0121] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0122] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A multi-peak maximum power search method, characterized in that: include: Setting the input voltage setting of the photovoltaic module to a first input voltage setting, and gradually increasing the input current setting limit to a preset maximum input current to search for an initial global maximum power point; wherein the first input voltage setting is less than the open-circuit voltage of the photovoltaic module; Obtaining a first input current corresponding to the first input voltage; Setting the input voltage given as a second input voltage given, and obtaining a second input current corresponding to the second input voltage given, wherein the second input voltage given is less than the first input voltage given; When the difference between the second input current and the first input current is greater than or equal to a preset difference, adjusting the input voltage setting by a preset voltage adjustment step size within a preset voltage range to perform power search and obtain a local maximum power point, wherein the first input voltage setting and the second input voltage setting are within the preset voltage range; A global maximum power point is determined according to the initial global maximum power point and the local maximum power point.

2. The method according to claim 1, wherein After setting the input voltage reference to a second input voltage reference and acquiring a second input current corresponding to the second input voltage reference, the method further includes: When the difference between the second input current and the first input current is smaller than a preset difference, the initial global maximum power point is determined to be the current global maximum power point.

3. The method according to claim 2, wherein A lower limit value of the preset voltage range is less than or equal to the second input voltage setting, and an upper limit value of the preset voltage range is greater than the first input voltage setting.

4. The method according to claim 1, wherein The step of adjusting the input voltage within the preset voltage range with a preset voltage adjustment step to perform power search and obtain a local maximum power point includes: Setting the input voltage to the lower limit of the preset voltage range, and gradually increasing it with the preset voltage adjustment step size until it reaches the upper limit of the preset voltage range, and determining the maximum input power of the photovoltaic module during the input voltage adjustment process as the local maximum power point; or The initial value of the given input voltage is set as the upper limit value of the preset voltage range, and the preset voltage adjustment step is gradually reduced to the lower limit value of the preset voltage range, and the maximum power point searched during the given input voltage adjustment process is determined as the local maximum power point.

5. The method according to claim 1, wherein The first input voltage is set between 75% and 85% of the open circuit voltage, and the second input voltage is set between 40% and 50% of the open circuit voltage.

6. The method according to claim 1, wherein The step of gradually increasing the input current limit to a preset maximum input current to search for an initial global maximum power point includes: performing a limiting process on the output of the input voltage loop of the photovoltaic module to obtain the input current setting; The amplitude limiting value of the amplitude limiting process is gradually increased from 0 to the preset maximum input current.

7. The method according to claim 1, wherein The determining of the global maximum power point according to the initial global maximum power point and the local maximum power point includes: A larger value between the initial global maximum power point and the local maximum power point is determined as the global maximum power point.

8. The method according to any one of claims 1 to 7, wherein: The method further comprises: After determining the global maximum power point, the input voltage is set to a voltage value corresponding to the global maximum power point, and a preset maximum power tracking algorithm is executed.

9. An electric power device, characterized in that: The method comprises a DC converter, a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the DC converter comprises a first end and a second end, the first end being used to connect to a photovoltaic module, the second end being used to connect to a DC bus, the DC bus being used to connect to one or more of a battery module, a load, and an inverter, and wherein when the processor executes the computer program, the steps of the multi-peak maximum power search method according to any one of claims 1 to 8 are implemented.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, which, when executed by a controller, can implement the steps of the multi-peak maximum power search method according to any one of claims 1 to 8.

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