Maximum power tracking method, device, controller and system of photovoltaic power generation system

Abstract

The embodiment of the invention provides a maximum power tracking method, device, controller and system of a photovoltaic power generation system. The method comprises the following steps: determining photovoltaic polling cycle time of a photovoltaic power generation system; wherein the photovoltaic polling cycle time represents the time for all the photovoltaic strings to complete one-time maximum power tracking processing; acquiring current information of the energy storage battery acquired by a current measuring device; and according to the photovoltaic polling cycle time and the current information, performing maximum power tracking processing on each photovoltaic string. According to the method, the maximum power tracking processing of the multi-path photovoltaic string can be completed on the basis of reducing the hardware usage amount, and the hardware cost is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of photovoltaic power generation, and particularly to a maximum power point tracking method, device, controller and system for a photovoltaic power generation system. Background Art

[0002] With the wide application of energy storage batteries, a new type of photovoltaic power generation system combining photovoltaic and energy storage has attracted attention. Since the output power of photovoltaic cells in a photovoltaic string is affected by factors such as temperature and sunlight intensity, at different ambient temperatures and light intensities, the photovoltaic cells can output different powers when operating at different output voltages. Therefore, in a photovoltaic power generation system, in order to enable the photovoltaic cells to operate at the maximum output power point, the photovoltaic power generation system must adjust the operating point of the photovoltaic cells according to the current light intensity and ambient temperature, and this adjustment process is called "Maximum Power Point Tracking (MPPT)".

[0003] In the prior art, a voltage measuring device and a current measuring device are connected to the output end of the photovoltaic cells to obtain the output power of the photovoltaic cells, and then the output power of the photovoltaic cells is adjusted according to a specific control algorithm until the maximum power point is reached.

[0004] However, in the above method, when the photovoltaic power generation system includes multiple photovoltaic cell inputs, multiple voltage measuring devices and multiple current measuring devices need to be connected to the output ends of the multiple photovoltaic cell strings, resulting in a high hardware cost. Summary of the Invention

[0005] Embodiments of the present application provide a maximum power point tracking method, device, controller and system for a photovoltaic power generation system, which can reduce the usage amount of measuring devices and lower the hardware cost.

[0006] In a first aspect, an embodiment of the present application provides a maximum power point tracking method for a photovoltaic power generation system, and the method is applied to a maximum power point tracking MPPT controller in the photovoltaic power generation system; the photovoltaic power generation system further includes an energy storage battery, a current measuring device and at least one photovoltaic string; the energy storage battery is electrically connected to each photovoltaic string through the current measuring device; the method includes:

[0007] Determine the photovoltaic polling cycle time of the photovoltaic power generation system; wherein, the photovoltaic polling cycle time represents the time for all photovoltaic strings to complete a maximum power point tracking process;

[0008] Obtain the current information of the energy storage battery collected by the current measuring device;

[0009] Perform maximum power point tracking processing on each photovoltaic string according to the photovoltaic polling cycle time and the current information.

[0010] In a possible implementation manner, the step of performing maximum power point tracking processing on each of the photovoltaic strings according to the photovoltaic polling cycle time and the current information includes:

[0011] Determining power perturbation information of each of the photovoltaic strings according to the current information; wherein, the power perturbation information characterizes the power perturbation direction of the photovoltaic string;

[0012] Performing maximum power point tracking processing on each of the photovoltaic strings according to the photovoltaic polling cycle time and each of the power perturbation information.

[0013] In a possible implementation manner, the photovoltaic power generation system further includes a voltage measuring device, and the voltage measuring device is connected in parallel with the energy storage battery; the photovoltaic polling cycle time includes at least one photovoltaic polling moment;

[0014] The step of determining power perturbation information of each of the photovoltaic strings according to the current information includes:

[0015] Obtaining voltage information of the energy storage battery collected by the voltage measuring device;

[0016] Determining the input power of the energy storage battery at the i-th photovoltaic polling moment according to the current value at the i-th photovoltaic polling moment in the current information and the voltage value at the i-th photovoltaic polling moment in the voltage information;

[0017] Determining the power perturbation information of the (i - 1)-th photovoltaic string according to the input power of the energy storage battery at the i-th photovoltaic polling moment and the input power of the energy storage battery at the (i - 1)-th photovoltaic polling moment.

[0018] In a possible implementation manner, the photovoltaic polling cycle time includes at least one photovoltaic polling moment; the step of performing maximum power point tracking processing on each of the photovoltaic strings according to the photovoltaic polling cycle time and each of the power perturbation information includes:

[0019] At the i-th photovoltaic polling moment, performing power perturbation processing on the i-th photovoltaic string according to the power perturbation information of the i-th photovoltaic string.

[0020] In a possible implementation manner, the photovoltaic power generation system further includes at least one MPPT converter; each of the photovoltaic strings is electrically connected to the current measuring device through each of the MPPT converters; the method further includes:

[0021] At the i-th photovoltaic polling moment, controlling the i-th MPPT converter to perform power perturbation processing on the i-th photovoltaic string according to the power perturbation information of the i-th photovoltaic string.

[0022] In a possible implementation, determining the photovoltaic polling cycle time of the photovoltaic power generation system includes:

[0023] Determining the photovoltaic polling cycle time according to the performance parameters of the MPPT controller.

[0024] In a possible implementation, determining the photovoltaic polling cycle time according to the performance parameters of the MPPT controller includes:

[0025] Determining the photovoltaic polling cycle time according to the performance parameters of the MPPT controller and the total number corresponding to each photovoltaic string.

[0026] In a second aspect, an embodiment of the present application provides a maximum power tracking device for a photovoltaic power generation system. The device is applied to a maximum power point tracking (MPPT) controller in the photovoltaic power generation system. The photovoltaic power generation system further includes a storage battery, a current measurement device, and at least one photovoltaic string. The storage battery is electrically connected to each photovoltaic string through the current measurement device. The device includes:

[0027] A determination module, configured to determine the photovoltaic polling cycle time of the photovoltaic power generation system, where the photovoltaic polling cycle time represents the time for all photovoltaic strings to complete a maximum power tracking process;

[0028] An acquisition module, configured to acquire the current information of the storage battery collected by the current measurement device;

[0029] A processing module, configured to perform maximum power tracking processing on each photovoltaic string according to the photovoltaic polling cycle time and the current information.

[0030] In a possible implementation, the processing module is specifically configured to: determine the power perturbation information of each photovoltaic string according to the current information, where the power perturbation information represents the power perturbation direction of the photovoltaic string; and perform maximum power tracking processing on each photovoltaic string according to the photovoltaic polling cycle time and each power perturbation information.

[0031] In a possible implementation manner, a voltage measurement device is further included in the photovoltaic power generation system, and the voltage measurement device is connected in parallel with the energy storage battery; the photovoltaic polling cycle time includes at least one photovoltaic polling moment; the processing module is specifically configured to: obtain the voltage information of the energy storage battery collected by the voltage measurement device; determine the input power of the energy storage battery at the i-th photovoltaic polling moment according to the current value at the i-th photovoltaic polling moment in the current information and the voltage value at the i-th photovoltaic polling moment in the voltage information; determine the power perturbation information of the (i - 1)-th photovoltaic string according to the input power of the energy storage battery at the i-th photovoltaic polling moment and the input power of the energy storage battery at the (i - 1)-th photovoltaic polling moment.

[0032] In a possible implementation manner, the photovoltaic polling cycle time includes at least one photovoltaic polling moment; the processing module is further specifically configured to: at the i-th photovoltaic polling moment, perform power perturbation processing on the i-th photovoltaic string according to the power perturbation information of the i-th photovoltaic string.

[0033] In a possible implementation manner, at least one MPPT converter is further included in the photovoltaic power generation system; each photovoltaic string is electrically connected to the current measurement device through each MPPT converter; the processing module is further specifically configured to: at the i-th photovoltaic polling moment, control the i-th MPPT converter to perform power perturbation processing on the i-th photovoltaic string according to the power perturbation information of the i-th photovoltaic string.

[0034] In a possible implementation manner, the determining module is specifically configured to: determine the photovoltaic polling cycle time according to the performance parameters of the MPPT controller.

[0035] In a possible implementation manner, the determining module is specifically configured to: determine the photovoltaic polling cycle time according to the performance parameters of the MPPT controller and the total number corresponding to each photovoltaic string.

[0036] In a third aspect, an embodiment of the present application provides a maximum power point tracking (MPPT) controller, and the MPPT controller is applied to a photovoltaic power generation system; an energy storage battery, a current measurement device, and at least one photovoltaic string are further included in the photovoltaic power generation system; the energy storage battery is electrically connected to each photovoltaic string through the current measurement device;

[0037] The MPPT controller includes: a memory, a processor;

[0038] The memory stores computer execution instructions;

[0039] The processor executes the computer-executable instructions stored in the memory, such that the processor performs the above first aspect and / or various possible implementation manners of the first aspect.

[0040] In a fourth aspect, an embodiment of the present application provides a photovoltaic power generation system, which includes a maximum power point tracking (MPPT) controller, a storage battery, a current measurement device, and at least one photovoltaic string; the storage battery is electrically connected to each of the photovoltaic strings through the current measurement device, and the MPPT controller is configured to implement the above first aspect and / or various possible implementation manners of the first aspect.

[0041] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium, in which computer-executable instructions are stored, and when the computer-executable instructions are executed by a processor, they are used to implement the above first aspect and / or various possible implementation manners of the first aspect.

[0042] In a sixth aspect, an embodiment of the present application provides a computer program product, including a computer program, and when the computer program is executed by a processor, it implements the above first aspect and / or various possible implementation manners of the first aspect.

[0043] The maximum power tracking method, device, controller, and system for the photovoltaic power generation system provided by the embodiments of the present application set a current measurement device on the side of the storage battery in the photovoltaic power generation system, and electrically connect the storage battery to all the photovoltaic strings through the current measurement device; the MPPT controller uses a photovoltaic polling cycle time, and performs maximum power tracking processing on all the photovoltaic strings according to the photovoltaic polling cycle time and the current information of the storage battery collected by the current measurement device; furthermore, maximum power tracking processing of multiple photovoltaic strings can be completed on the basis of reducing the amount of hardware used, and the hardware cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0045] Figure 1 It is a schematic structural diagram of a photovoltaic power generation system based on multiple photovoltaic strings provided by the present application;

[0046] Figure 2 It is a schematic flowchart of a maximum power tracking method for a photovoltaic power generation system provided by an embodiment of the present application;

[0047] Figure 3 It is a schematic flowchart of another maximum power tracking method for a photovoltaic power generation system provided by an embodiment of the present application;

[0048] Figure 4 A schematic structural diagram of a photovoltaic power generation system provided by an embodiment of the present application;

[0049] Figure 5 A schematic diagram of the principle of a maximum power tracking process provided by an embodiment of the present application;

[0050] Figure 6 A schematic structural diagram of another photovoltaic power generation system provided by an embodiment of the present application;

[0051] Figure 7 A schematic structural diagram of a maximum power tracking device of a photovoltaic power generation system provided by an embodiment of the present application;

[0052] Figure 8 A schematic structural diagram of an MPPT controller provided by an embodiment of the present application.

[0053] Through the above-mentioned drawings, the specific embodiments of the present application have been shown, and there will be more detailed descriptions hereinafter. These drawings and textual descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. Specific Embodiments

[0054] Here, the exemplary embodiments will be described in detail, and their examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0055] It should be noted that the present application can be used in the field of photovoltaic power generation technology, and can also be used in any field other than the field of photovoltaic power generation technology. The application field of the present application is not limited.

[0056] With the wide application of energy storage batteries, new photovoltaic power generation systems combining photovoltaics and energy storage have received attention. Since the output power of photovoltaic cells in a photovoltaic string is affected by factors such as temperature and sunlight intensity, under different ambient temperatures and light intensities, the photovoltaic cells can output different powers when working at different output voltages. Therefore, in a photovoltaic power generation system, in order to make the photovoltaic cells work at the maximum output power point, maximum power point tracking is required.

[0057] In one example, Figure 1 A schematic structural diagram of a photovoltaic power generation system based on multiple photovoltaic strings provided by the present application, as Figure 1As shown in the figure, a photovoltaic power generation system includes multiple photovoltaic cells (photovoltaic string 1, photovoltaic string 2, …, photovoltaic string n), multiple direct current / direct current converters (Direct Current to Direct Current Converter, abbreviated as DC / DC converter), a storage battery, and an MPPT controller. The output end of each photovoltaic string is connected to a voltage measuring device and a current measuring device. Each current measuring device is electrically connected to the storage battery through each DC / DC converter. Based on the MPPT controller, the battery power of each photovoltaic cell is obtained by multiplying the voltage collected by the voltage measuring device and the current collected by the current measuring device, and then according to a specific control algorithm (perturbation observation or conductance increment), each DC / DC converter is controlled to adjust the output power of the corresponding photovoltaic string until the maximum power point is reached.

[0058] Combined with the above scenario, it can be seen that when there are multiple inputs of photovoltaic cells, voltage measuring devices and current measuring devices need to be installed for each photovoltaic cell, resulting in the technical problem of relatively high hardware costs.

[0059] The maximum power tracking method of the photovoltaic power generation system provided by this application sets a current measuring device on the side of the storage battery in the photovoltaic power generation system, and electrically connects the storage battery to all photovoltaic strings through the current measuring device. Using the photovoltaic polling cycle time, according to the photovoltaic polling cycle time and the current information of the storage battery collected by the current measuring device, maximum power tracking processing is performed on all photovoltaic strings, solving the technical problem of relatively high hardware costs.

[0060] The following uses specific embodiments to detail the technical solution of this application and how the technical solution of this application solves the above technical problems. These specific embodiments below can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of this application will be described below with reference to the drawings.

[0061] Figure 2 It is a schematic flow chart of a maximum power tracking method for a photovoltaic power generation system provided by an embodiment of this application. As Figure 2 shown, the method includes:

[0062] 201. Determine the photovoltaic polling cycle time of the photovoltaic power generation system; wherein, the photovoltaic polling cycle time represents the time for the photovoltaic power generation system to complete one maximum power tracking process.

[0063] Exemplarily, the execution subject of this embodiment may be a maximum power point tracking (MPPT) controller in a photovoltaic power generation system; the photovoltaic power generation system further includes a storage battery, a current measurement device such as a current sensor, and at least one photovoltaic string (photovoltaic string 1, photovoltaic string 2, …, photovoltaic string n); one end of the storage battery is electrically connected to one end of all photovoltaic strings through the current measurement device; the other end of the storage battery is directly electrically connected to the other end of all photovoltaic strings. Based on the MPPT controller, the preset photovoltaic polling cycle time of the photovoltaic power generation system is called; the photovoltaic polling cycle time represents the time for all photovoltaic strings in the photovoltaic power generation system to complete one maximum power tracking process; for example, the photovoltaic polling cycle time corresponding to the photovoltaic power generation system can be determined in advance through the photovoltaic cell parameters of all photovoltaic strings in the photovoltaic power generation system, such as 5 ms to 100 ms, and stored in the MPPT controller. When starting all photovoltaic strings to generate power, the photovoltaic polling cycle time is called for processing.

[0064] 202. Obtain the current information of the storage battery collected by the current measurement device.

[0065] Exemplarily, the current measurement device monitors the current information on one side of the storage battery in real time and transmits it to the MPPT controller. Based on the MPPT controller, the current information of the storage battery collected at the current measurement device can be received in real time.

[0066] For example, when starting the maximum power tracking process of the photovoltaic power generation system, the MPPT controller of the photovoltaic power generation system monitors the current value of the storage battery at each moment in real time through the current measurement device, or obtains the current change of the storage battery within the photovoltaic polling cycle time.

[0067] 203. Perform maximum power tracking processing on each photovoltaic string according to the photovoltaic polling cycle time and the current information.

[0068] Exemplarily, when starting the maximum power tracking process of the photovoltaic power generation system, the MPPT controller of the photovoltaic power generation system performs one maximum power tracking process on all photovoltaic strings within a determined photovoltaic polling cycle time based on a preset maximum power tracking algorithm (such as the perturbation observation method or the incremental conductance method) according to the current information of the storage battery.

[0069] For example, within each photovoltaic polling cycle time, based on the current information of the energy storage battery at the first moment within the photovoltaic polling cycle time, the magnitude of the current on one side of the energy storage battery is determined. Based on the increase and decrease of the input power of the photovoltaic modules, the increase and decrease of the power on the energy storage battery side are synchronously reflected. Therefore, the change in the current on one side of the energy storage battery can be used to reflect the power changes of all photovoltaic strings, such as getting larger or smaller. According to this change in current, through a preset maximum power point tracking method, all photovoltaic strings are subjected to one maximum power point tracking process one by one in a preset order; according to this photovoltaic polling cycle time, the maximum power point tracking process is continuously performed on all photovoltaic strings.

[0070] For another example, within each photovoltaic polling cycle time, based on the current information of the energy storage battery at the first moment within the photovoltaic polling cycle time, the magnitude of the current on one side of the energy storage battery is determined to reflect the output power of all photovoltaic strings. According to this magnitude of the current, through a preset maximum power point tracking method, all photovoltaic strings are simultaneously subjected to one maximum power point tracking process; according to this photovoltaic polling cycle time, the above maximum power point tracking process is continuously repeated.

[0071] In this embodiment, a method for maximum power point tracking of a photovoltaic power generation system is provided. The current measurement device is placed on one side of the energy storage battery. The current information of the energy storage battery collected by the current measurement device is used to reflect the power changes of each photovoltaic string, which can reduce the usage of sensors and lower costs; furthermore, in combination with the photovoltaic polling cycle time, maximum power point tracking processing is performed on each photovoltaic string according to this current information; furthermore, power tracking of multiple photovoltaic strings can be completed with fewer sensors.

[0072] Figure 3 For the flowchart of another method for maximum power point tracking of a photovoltaic power generation system provided by an embodiment of the present application, as Figure 3 shown, the method includes:

[0073] 301. Determine the photovoltaic polling cycle time according to the performance parameters of the MPPT controller.

[0074] Exemplarily, based on the MPPT controller, the pre-set performance parameters of the MPPT controller itself are obtained, such as including the maximum power point tracking efficiency, switching period, and response time information. The response time information includes dynamic response time, steady-state response time, and sampling frequency; according to the performance parameters of the MPPT controller, the photovoltaic polling cycle time corresponding to the performance parameters is determined.

[0075] In one example, step 301 includes: determining the photovoltaic polling cycle time according to the performance parameters of the MPPT controller and the total number corresponding to each photovoltaic string.

[0076] Exemplarily, after obtaining the performance parameters of the MPPT controller itself set in advance based on the MPPT controller, the total number of all photovoltaic strings set in advance in the photovoltaic power generation system is also obtained; based on a preset processing rule, the performance parameters of the MPPT controller and the total number of all photovoltaic strings can be analyzed to determine the photovoltaic polling cycle time corresponding to the performance parameters.

[0077] For example, based on the MPPT controller, the device performance parameters corresponding to each photovoltaic string in the photovoltaic power generation system can be obtained first, and then based on a preset processing rule, the performance parameters of the MPPT controller, the total number of all photovoltaic strings, and the device performance parameters corresponding to each photovoltaic string are analyzed to determine the photovoltaic polling cycle time corresponding to the performance parameters.

[0078] 302. Obtain the current information of the energy storage battery collected by the current measuring device.

[0079] Exemplarily, this step can refer to step 202 and will not be elaborated here.

[0080] 303. Determine the power disturbance information of each photovoltaic string according to the current information; wherein, the power disturbance information characterizes the power disturbance direction of the photovoltaic string.

[0081] Exemplarily, when starting the maximum power tracking process of the photovoltaic power generation system, based on a preset maximum power tracking algorithm (such as the perturbation observation method or the conductance increment method), according to the current information of the energy storage battery collected, the power situation corresponding to each photovoltaic string can be reflected. Furthermore, according to the current information, the power disturbance direction of each photovoltaic string is determined.

[0082] For example, within the photovoltaic polling cycle time 1, according to the current information of the energy storage battery at the first moment within the photovoltaic polling cycle time 1, the current magnitude on the side of the energy storage battery is determined to reflect the output power situation of the photovoltaic string. According to this current magnitude, through a preset maximum power tracking method, the first maximum power tracking process is performed on photovoltaic string 1, and the control of other photovoltaic strings remains unchanged; within the photovoltaic polling cycle time 2, according to the current information of the energy storage battery at the first moment within the photovoltaic polling cycle time 2, the current change situation on the side of the energy storage battery is determined to reflect the output power change situation of photovoltaic string 1, such as getting larger or smaller. According to this current change situation, the next power disturbance direction of photovoltaic string 1 can be determined. Among them, within the photovoltaic polling cycle time (millisecond level), the voltage on the side of the energy storage battery can be considered constant, and the power change on the side of the photovoltaic string can be reflected through the current change situation of the energy storage battery, so that only one current sensor is needed.

[0083] In one example, the photovoltaic power generation system further includes a voltage measuring device, which is connected in parallel with the energy storage battery; the photovoltaic polling cycle time includes at least one photovoltaic polling moment; step 303 includes the following steps:

[0084] The first step is to obtain the voltage information of the energy storage battery collected by the voltage measuring device.

[0085] The second step is to determine the input power of the energy storage battery at the i-th photovoltaic polling moment according to the current value at the i-th photovoltaic polling moment in the current information and the voltage value at the i-th photovoltaic polling moment in the voltage information.

[0086] The third step is to determine the power perturbation information of the (i - 1)-th photovoltaic string according to the input power of the energy storage battery at the i-th photovoltaic polling moment and the input power of the energy storage battery at the (i - 1)-th photovoltaic polling moment.

[0087] Exemplarily, Figure 4 is a schematic structural diagram of a photovoltaic power generation system provided by an embodiment of the present application. As Figure 4 shown, the photovoltaic power generation system further includes a voltage measuring device, which is connected in parallel with the energy storage battery; the photovoltaic power generation system further includes at least one MPPT converter; each photovoltaic string is connected in parallel with each MPPT converter, one end of each MPPT converter is electrically connected to the current measuring device, and the other end of each MPPT converter is electrically connected to the energy storage battery. The photovoltaic polling cycle time includes at least one photovoltaic polling moment; for example, a photovoltaic polling cycle time Tpv parameter value includes a plurality of photovoltaic polling moments, and there is a small time slice between every two photovoltaic polling moments. Within a photovoltaic polling cycle time, the MPPT controller can obtain the voltage information of the energy storage battery in real time through the voltage measuring device, including the voltage value of the energy storage battery at each photovoltaic polling moment. The MPPT controller can obtain the current information of the energy storage battery in real time through the current measuring device, including the current value of the energy storage battery at each photovoltaic polling moment. For each photovoltaic polling moment within each photovoltaic polling cycle time, the MPPT controller determines the input power of the energy storage battery at the i-th photovoltaic polling moment according to the current value at the i-th photovoltaic polling moment and the voltage value at the i-th photovoltaic polling moment, by multiplying the voltage value and the current value, and obtains the input power of the energy storage battery at the (i - 1)-th photovoltaic polling moment. The input power of the energy storage battery at the i-th photovoltaic polling moment and the input power of the energy storage battery at the (i - 1)-th photovoltaic polling moment are compared to obtain the power change situation of the energy storage battery, so as to reflect the power change situation of the (i - 1)-th photovoltaic string. Based on a preset maximum power tracking method (perturbation observation method or conductance increment method), the power perturbation information of the (i - 1)-th photovoltaic string can be determined, that is, the next power perturbation direction of the (i - 1)-th photovoltaic string.

[0088] 304. Perform maximum power point tracking processing on each photovoltaic string according to the photovoltaic polling cycle time and each power disturbance information.

[0089] Exemplarily, the MPPT controller completes the maximum power point tracking processing on all photovoltaic strings within the photovoltaic polling cycle time according to the power disturbance direction of each photovoltaic string.

[0090] For example, within each photovoltaic polling cycle time, perform maximum power point tracking processing on each photovoltaic string simultaneously according to the power disturbance direction of each photovoltaic string; or, within one photovoltaic polling cycle time, perform maximum power point tracking processing on each photovoltaic string in sequence according to a preset order according to the power disturbance direction of each photovoltaic string.

[0091] In one example, the photovoltaic polling cycle time includes at least one photovoltaic polling moment; step 304 includes: at the i-th photovoltaic polling moment, perform power disturbance processing on the i-th photovoltaic string according to the power disturbance information of the i-th photovoltaic string.

[0092] Specifically, the photovoltaic polling cycle time includes at least one photovoltaic polling moment. For example, the photovoltaic polling cycle time is divided into multiple time slices, and the first moment of each time slice is each photovoltaic polling moment. Within one photovoltaic polling cycle time, at the i-th photovoltaic polling moment, the MPPT controller performs power disturbance processing on the i-th photovoltaic string according to the power disturbance direction of the i-th photovoltaic string.

[0093] For example, Figure 5 is a schematic diagram of the principle of a maximum power point tracking process provided by an embodiment of the present application, as Figure 4 、 5As shown, the photovoltaic power generation system includes n photovoltaic strings. Within a photovoltaic polling cycle time Tpv, there are n photovoltaic polling moments. At the 1st photovoltaic polling moment, the current information of the energy storage battery collected by the current measurement device and the voltage information of the energy storage battery collected by the voltage measurement device can be used to record the current power P1 at the 1st photovoltaic polling moment. Based on the relationship between this P1 and the current power P at the nth photovoltaic polling moment in the previous photovoltaic polling cycle time Tpv, such as whether the power increases or decreases, to reflect the next power disturbance direction of the photovoltaic string n, and according to the power disturbance direction of the photovoltaic string 1 determined in the previous photovoltaic polling cycle time Tpv, perform power disturbance on the photovoltaic string 1; at the 2nd photovoltaic polling moment, the current information of the energy storage battery collected by the current measurement device and the voltage information of the energy storage battery collected by the voltage measurement device can be used to record the current power P2 at the 2nd photovoltaic polling moment. Based on the relationship between this P2 and the current power P1 at the 1st photovoltaic polling moment in this photovoltaic polling cycle time Tpv, such as whether the power increases or decreases, to reflect the power disturbance direction of the photovoltaic string 1 in the next photovoltaic polling cycle time Tpv, and according to the power disturbance direction of the photovoltaic string 2 determined in the previous photovoltaic polling cycle time Tpv, perform power disturbance on the photovoltaic string 2; at the 3rd photovoltaic polling moment, the current information of the energy storage battery collected by the current measurement device and the voltage information of the energy storage battery collected by the voltage measurement device can be used to record the current power P3 at the 3rd photovoltaic polling moment. Based on the relationship between this P3 and the current power P2 at the 2nd photovoltaic polling moment in this photovoltaic polling cycle time Tpv, such as whether the power increases or decreases, to reflect the power disturbance direction of the photovoltaic string 2 in the next photovoltaic polling cycle time Tpv, and according to the power disturbance direction of the photovoltaic string 3 determined in the previous photovoltaic polling cycle time Tpv, perform power disturbance on the photovoltaic string 3; according to the above process, until at the nth photovoltaic polling moment, the current information of the energy storage battery collected by the current measurement device and the voltage information of the energy storage battery collected by the voltage measurement device can be used to record the current power P n , according to this P n and the current power P n-1 at the (n - 1)th photovoltaic polling moment in this photovoltaic polling cycle time Tpv, such as whether the power increases or decreases, to reflect the power disturbance direction of the photovoltaic string n - 1 in the next photovoltaic polling cycle time Tpv, and according to the power disturbance direction of the photovoltaic string n determined in the previous photovoltaic polling cycle time Tpv, perform power disturbance on the photovoltaic string n. The photovoltaic polling cycle time is adopted. Only one photovoltaic string is subjected to maximum power tracking at each photovoltaic polling moment, and the control of other photovoltaic strings remains unchanged. It is possible to complete the power tracking of multiple photovoltaic strings with fewer sensors.

[0094] In one example, the photovoltaic power generation system further includes at least one MPPT converter; each photovoltaic string is electrically connected to the current measuring device through each MPPT converter; step 304 further includes: at the i-th photovoltaic polling moment, according to the power perturbation information of the i-th photovoltaic string, controlling the i-th MPPT converter to perform power perturbation processing on the i-th photovoltaic string.

[0095] Exemplarily, Figure 6 FIG. is a schematic structural diagram of another photovoltaic power generation system provided by an embodiment of the present application. As Figure 6 shown, the photovoltaic power generation system further includes at least one MPPT converter; each photovoltaic string is connected in parallel with each MPPT converter. One end of each MPPT converter is electrically connected to the current measuring device, and the other end of each MPPT converter is electrically connected to the energy storage battery. Within each photovoltaic polling cycle time, at the i-th photovoltaic polling moment, maximum power tracking is performed on only one photovoltaic string at a time, and the control of other photovoltaic MPPT converters remains unchanged. Therefore, within the time of Tpv / n, the power change situation on the energy storage battery side reflects the power change situation of this photovoltaic string. According to the traditional maximum power tracking method (perturbation observation method or conductance increment method), the control direction of this photovoltaic string can be determined. The MPPT controller can control the i-th MPPT converter to perform power perturbation processing on the i-th photovoltaic string in accordance with the power perturbation direction of the i-th photovoltaic string by sending a control signal to the i-th MPPT converter according to the power perturbation direction of the i-th photovoltaic string.

[0096] In this embodiment, on the basis of the above embodiment, on the one hand, the voltage measuring device and the current measuring device are placed on the energy storage battery side, reducing the number of sensors used and lowering the cost; on the other hand, a photovoltaic polling cycle is adopted, and maximum power tracking is performed on only a single photovoltaic string in each small time slice, so that maximum power tracking of multiple photovoltaic strings can be completed with fewer sensors.

[0097] Figure 7 FIG. is a schematic structural diagram of a maximum power tracking device of a photovoltaic power generation system provided by an embodiment of the present application. As Figure 7 shown, the device is applied to a maximum power point tracking MPPT controller in a photovoltaic power generation system; the photovoltaic power generation system further includes an energy storage battery, a current measuring device, and at least one photovoltaic string; the energy storage battery is electrically connected to each photovoltaic string through the current measuring device; the device includes:

[0098] A determination module 401, configured to determine the photovoltaic polling cycle time of the photovoltaic power generation system; wherein, the photovoltaic polling cycle time represents the time for all photovoltaic strings to complete one maximum power tracking process;

[0099] An acquisition module 402, configured to acquire current information of an energy storage battery collected by a current measurement device;

[0100] A processing module 403, configured to perform maximum power point tracking processing on each photovoltaic string according to a photovoltaic polling cycle time and the current information.

[0101] In a possible implementation manner, the processing module 403 is specifically configured to: determine power perturbation information of each photovoltaic string according to the current information, where the power perturbation information characterizes the power perturbation direction of the photovoltaic string; and perform maximum power point tracking processing on each photovoltaic string according to the photovoltaic polling cycle time and each power perturbation information.

[0102] In a possible implementation manner, the photovoltaic power generation system further includes a voltage measurement device, and the voltage measurement device is connected in parallel with the energy storage battery; the photovoltaic polling cycle time includes at least one photovoltaic polling moment; the processing module 403 is specifically configured to: acquire voltage information of the energy storage battery collected by the voltage measurement device; determine the input power of the energy storage battery at the i-th photovoltaic polling moment according to the current value at the i-th photovoltaic polling moment in the current information and the voltage value at the i-th photovoltaic polling moment in the voltage information; and determine the power perturbation information of the (i - 1)-th photovoltaic string according to the input power of the energy storage battery at the i-th photovoltaic polling moment and the input power of the energy storage battery at the (i - 1)-th photovoltaic polling moment.

[0103] In a possible implementation manner, the photovoltaic polling cycle time includes at least one photovoltaic polling moment; the processing module 403 is further specifically configured to: perform power perturbation processing on the i-th photovoltaic string according to the power perturbation information of the i-th photovoltaic string at the i-th photovoltaic polling moment.

[0104] In a possible implementation manner, the photovoltaic power generation system further includes at least one MPPT converter; each photovoltaic string is electrically connected to the current measurement device through each MPPT converter; the processing module 403 is further specifically configured to: control the i-th MPPT converter to perform power perturbation processing on the i-th photovoltaic string according to the power perturbation information of the i-th photovoltaic string at the i-th photovoltaic polling moment.

[0105] In a possible implementation manner, the determination module 401 is specifically configured to: determine the photovoltaic polling cycle time according to the performance parameters of the MPPT controller.

[0106] In a possible implementation manner, the determination module 401 is specifically configured to: determine the photovoltaic polling cycle time according to the performance parameters of the MPPT controller and the total number corresponding to each photovoltaic string.

[0107] The device in this embodiment can execute the technical solutions in the above method, and the specific implementation process and technical principle are the same, which will not be elaborated here.

[0108] Figure 8 The following is a schematic structural diagram of an MPPT controller provided by an embodiment of the present application. As Figure 8 shown, the MPPT controller includes: a memory 501 and a processor 502; the memory 501 is a memory for storing executable instructions of the processor 502.

[0109] Among them, the processor 502 is configured to execute the method provided in the above embodiment.

[0110] The MPPT controller further includes a receiver 503 and a transmitter 504. The receiver 503 is used to receive instructions and data sent by other devices, and the transmitter 504 is used to send instructions and data to external devices.

[0111] For the specific implementation process of the processor, reference may be made to the above method embodiment. The implementation principle and technical effects are similar, and will not be elaborated here in this embodiment.

[0112] In the above embodiment, it should be understood that the processor may be a central processing unit (Central Processing Unit, abbreviated as CPU), or other general-purpose processors, digital signal processors (Digital Signal Processor, abbreviated as DSP), application specific integrated circuits (Application Specific Integrated Circuit, abbreviated as ASIC), etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The steps of the method disclosed in combination with the invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules in the processor.

[0113] An embodiment of the present application further provides a photovoltaic power generation system, which includes a maximum power point tracking MPPT controller, a storage battery, a current measurement device, and at least one photovoltaic string; the storage battery is electrically connected to each photovoltaic string through the current measurement device, and the MPPT controller is used to execute the technical solution in the above embodiment.

[0114] An embodiment of the present application further provides a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions run on a computer, the computer is caused to execute the technical solution in the above embodiment.

[0115] The above-readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory, electrically erasable programmable read-only memory, erasable programmable read-only memory, programmable read-only memory, read-only memory, magnetic memory, flash memory, magnetic disk or optical disk. The readable storage medium can be any available medium accessible by a general-purpose or special-purpose computer.

[0116] An exemplary readable storage medium is coupled to the processor, enabling the processor to read information from the readable storage medium and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can be located in an application-specific integrated circuit. Of course, the processor and the readable storage medium can also exist as discrete components in a device.

[0117] The embodiments of the present application also provide a computer program product. The computer program product includes a computer program stored in a computer-readable storage medium. At least one processor can read the computer program from the computer-readable storage medium, and when at least one processor executes the computer program, the technical solutions in the above embodiments can be implemented.

[0118] If the function is implemented in the form of 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 technical solution of the present invention, in essence, or the part that contributes to the prior art or a part of this technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods in the various embodiments of the present invention. The foregoing storage medium includes: USB flash drive, mobile hard disk, read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk, etc., which can store program codes.

[0119] Those of ordinary skill in the art can understand that all or part of the steps of implementing the above method embodiments can be completed by hardware related to program instructions. The foregoing program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps including the above method embodiments; and the foregoing storage medium includes: ROM, RAM, magnetic disk, or optical disk, etc., which can store program codes.

[0120] Finally, it should be noted that: those skilled in the art will readily conceive of other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention, which follow the general principles of the present invention and include common general knowledge or conventional technical means in the technical field not disclosed in the present invention. It is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present invention is only limited by the appended claims.

Claims

1. A maximum power tracking method for a photovoltaic power generation system, characterized in that: The method is applied to a maximum power point tracking MPPT controller in a photovoltaic power generation system; the photovoltaic power generation system also includes an energy storage battery, a current measuring device and at least one photovoltaic string; the energy storage battery is electrically connected to each photovoltaic string through the current measuring device; the method includes: Determine the photovoltaic polling cycle time of the photovoltaic power generation system; wherein the photovoltaic polling cycle time represents the time for all photovoltaic strings to complete a maximum power tracking process; Acquiring current information of the energy storage battery collected by the current measuring device; According to the photovoltaic polling cycle time and the current information, maximum power tracking processing is performed on each photovoltaic string.

2. The method according to claim 1, characterized in that The performing maximum power tracking processing on each photovoltaic string according to the photovoltaic polling cycle time and the current information includes: Determine the power disturbance information of each photovoltaic string according to the current information; wherein the power disturbance information represents the power disturbance direction of the photovoltaic string; According to the photovoltaic polling cycle time and each of the power disturbance information, a maximum power tracking process is performed on each of the photovoltaic strings.

3. The method according to claim 2, characterized in that The photovoltaic power generation system also includes a voltage measuring device, which is connected in parallel with the energy storage battery; the photovoltaic polling cycle time includes at least one photovoltaic polling time; The step of determining the power disturbance information of each photovoltaic string according to the current information includes: Acquiring voltage information of the energy storage battery collected by the voltage measuring device; Determine the input power of the energy storage battery at the i-th photovoltaic polling moment according to the current value at the i-th photovoltaic polling moment in the current information and the voltage value at the i-th photovoltaic polling moment in the voltage information; The power disturbance information of the i-1 th photovoltaic string is determined according to the input power of the energy storage battery at the i-th photovoltaic polling moment and the input power of the energy storage battery at the i-1 th photovoltaic polling moment.

4. The method according to claim 2, characterized in that: The photovoltaic polling cycle time includes at least one photovoltaic polling time; the maximum power tracking processing of each photovoltaic string according to the photovoltaic polling cycle time and each power disturbance information includes: At the i-th photovoltaic polling time, power disturbance processing is performed on the i-th photovoltaic string according to the power disturbance information of the i-th photovoltaic string.

5. The method according to claim 4, characterized in that The photovoltaic power generation system further includes at least one MPPT converter; each photovoltaic string is electrically connected to the current measuring device through each MPPT converter; and the method further includes: At the i-th photovoltaic polling moment, according to the power disturbance information of the i-th photovoltaic string, the i-th MPPT converter is controlled to perform power disturbance processing on the i-th photovoltaic string.

6. The method according to any one of claims 1 to 5, characterized in that Determining the photovoltaic polling cycle time of the photovoltaic power generation system includes: The photovoltaic polling cycle time is determined according to the performance parameters of the MPPT controller.

7. The method according to claim 6, characterized in that Determining the photovoltaic polling cycle time according to the performance parameters of the MPPT controller includes: The photovoltaic polling cycle time is determined according to the performance parameters of the MPPT controller and the total number of photovoltaic strings.

8. A maximum power tracking device for a photovoltaic power generation system, characterized in that: The device is applied to a maximum power point tracking MPPT controller in a photovoltaic power generation system; the photovoltaic power generation system also includes an energy storage battery, a current measuring device and at least one photovoltaic string; the energy storage battery is electrically connected to each photovoltaic string through the current measuring device; the device includes: A determination module, used to determine the photovoltaic polling cycle time of the photovoltaic power generation system; wherein the photovoltaic polling cycle time represents the time for all photovoltaic strings to complete a maximum power tracking process; An acquisition module, used to acquire the current information of the energy storage battery collected by the current measuring device; A processing module is used to perform maximum power tracking processing on each photovoltaic string according to the photovoltaic polling cycle time and the current information.

9. A maximum power point tracking MPPT controller, characterized in that: The MPPT controller is applied to a photovoltaic power generation system; the photovoltaic power generation system further comprises an energy storage battery, a current measuring device and at least one photovoltaic string; the energy storage battery is electrically connected to each photovoltaic string through the current measuring device; The MPPT controller includes: a memory and a processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory, so that the processor performs the method according to any one of claims 1 to 7.

10. A photovoltaic power generation system, characterized in that: The photovoltaic power generation system includes a maximum power point tracking MPPT controller, an energy storage battery, a current measuring device and at least one photovoltaic string; the energy storage battery is electrically connected to each of the photovoltaic strings through the current measuring device; the MPPT controller is used to implement the method described in any one of claims 1-7.

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