DC / DC wave sending method and device of photovoltaic power supply equipment in MPPT mode

Abstract

The invention discloses a DC / DC wave sending method and device of photovoltaic power supply equipment in an MPPT mode. The method comprises the following steps: constructing a photovoltaic cell simulation source; adjusting a second-stage direct-current topology in the photovoltaic equipment to output different output voltages, and adjusting load power to trigger switching to an MPPT (Maximum Power Point Tracking) mode; after switching, determining an effective wave sending parameter when peak power is reached according to the adjusted wave sending parameter of the switch tube adopting open-loop wave sending in the second-stage direct current topology; fitting the effective wave sending parameters corresponding to the same output voltage and different peak powers, and updating the effective wave sending parameters corresponding to the same output voltage; and performing relation function fitting based on the effective wave sending parameters corresponding to the updated output voltage to obtain a mathematical model mapping the relation between the output voltage and the effective wave sending parameters. Therefore, the problems that the tracking precision of the maximum power point and the stability of power supply equipment are affected and the reliability and the service life of related devices are reduced due to the fact that an existing control loop adopts complete closed-loop control are solved.

Description

Background Art

[0002] With the continuous rise of new energy, especially photovoltaic energy, MPPT (Maximum Power Point Tracking) technology helps people maximize the utilization of photovoltaic energy. Most of the topologies of existing photovoltaic DC-DC (Direct Current to Direct Current) power supply devices are Boost+DC / DC topologies. As Figure 1 shown, Boost is the first-stage DC topology, also known as the DC buck-boost topology, and the DC / DC topology is the second-stage DC topology.

[0003] The control loop of the photovoltaic DC-DC power supply device has an input voltage loop and a bus voltage loop of the first-stage DC topology, as well as an output voltage loop, an output current loop, and a power loop of the second-stage DC topology. Among them: the input voltage loop is used to control the input voltage V in of the first-stage DC topology, and the input current of the first-stage DC topology is I in ; the bus voltage loop is used to control the bus voltage V bus of the first-stage DC topology, that is, the output voltage of the first-stage DC topology; the output voltage loop of the second-stage DC topology is used to control the output voltage V o of the device, the output current loop is used to control the output current I o of the device, and the power loop is used to control the output power of the device, etc.

[0004] Since the above control loop adopts a fully closed-loop control, in the MPPT mode, when tracking the maximum power point, the switching frequency and duty cycle of the switching tube in the loop of the second-stage DC topology change at all times. These rapid changes will be coupled to the first-stage DC topology, thereby having a certain impact on the input voltage, and finally affecting the tracking accuracy of the maximum power point and the stability of the power supply device operation.

[0005] When switching back and forth between the MPPT mode and the non-MPPT mode, the current in the second-stage DC topology will be too large instantaneously during the control loop switching, which may affect the normal operation of the device and reduce the reliability and lifespan of related components. Summary of the Invention

[0006] The purpose of this application is to provide a DC / DC wave generation method and device for a photovoltaic power supply device in the MPPT mode, which is used to solve the problems existing in the existing control loop adopting a fully closed-loop control, such as affecting the tracking accuracy of the maximum power point, the stability of the power supply device operation, and reducing the reliability and lifespan of related components.

[0007] In a first aspect, an embodiment of the present application provides a DC / DC wave generation method for a photovoltaic power supply device in the MPPT mode. The method includes:

[0008] Construct a photovoltaic cell simulation source;

[0009] Based on the photovoltaic cell simulation source, adjust the output voltage of the second-stage DC topology in the photovoltaic device, and adjust the load power according to the different peak powers of the photovoltaic cell simulation source to trigger a switch to the MPPT mode;

[0010] When switching to the MPPT mode, determine the effective wave generation parameters when the output power of the photovoltaic cell simulation source reaches the peak power according to the wave generation parameters of the switching tubes that use open-loop wave generation in the adjusted second-stage DC topology;

[0011] Fit the effective wave generation parameters corresponding to the same output voltage and different peak powers respectively, and update the fitted effective wave generation parameters to the effective wave generation parameters corresponding to the same output voltage;

[0012] Based on the updated effective wave generation parameters corresponding to different output voltages respectively, perform a relationship function fitting to obtain a mathematical model that maps the relationship between the output voltage and the effective wave generation parameters, so as to determine the DC / DC wave generation parameters of the photovoltaic power supply device in the MPPT mode based on the mathematical model.

[0013] In some possible embodiments, after determining the effective wave generation parameters when the output power of the photovoltaic cell simulation source reaches the peak power, it further includes:

[0014] Determine the output power according to the current output voltage and output current of the second-stage DC topology, or determine the input power according to the current input voltage and input current of the first-stage DC topology in the photovoltaic device;

[0015] The fitting of the effective wave generation parameters corresponding to the same output voltage and different peak powers respectively includes:

[0016] When it is determined that the different effective wave generation parameters corresponding to the same output voltage and different peak powers do not meet the fitting requirements, segment the corresponding input power or output power, and the different effective wave generation parameters corresponding to the same output voltage and different peak powers in the same input / output power segment meet the fitting requirements;

[0017] Fit the different effective wave generation parameters corresponding to the same output voltage and different peak powers in the same input / output power segment into one effective wave generation parameter;

[0018] Based on the updated effective wave generation parameters corresponding to different output voltages respectively, perform a relationship function fitting to obtain a mathematical model that maps the relationship between the output voltage and the effective wave generation parameters, including:

[0019] For the effective wave generation parameters corresponding to different updated output voltages under the same input / output power range, perform relationship function fitting to obtain a mathematical model that maps the output voltage to the effective wave generation parameters under each input / output power range.

[0020] In some possible embodiments, adjusting the output voltages of the second-stage DC topology in the photovoltaic device and adjusting the load power according to the different peak powers of the photovoltaic cell simulation source to trigger a switch to the MPPT mode includes:

[0021] Adjust the load power to a peak power and keep it unchanged, and perform a round of output voltage adjustment based on the voltage adjustment range of the output voltage;

[0022] Each time the output voltage is adjusted, trigger a switch to the MPPT mode;

[0023] Each time a round of output voltage adjustment is completed, when it is determined that a round of adjustment of the load power is not completed, perform an adjustment of the load power and trigger the next round of output voltage adjustment;

[0024] Among them, a round of output voltage adjustment is completed by increasing or decreasing the output voltage within the voltage adjustment range according to the set voltage adjustment amplitude, and a round of load power adjustment is completed by increasing or decreasing the load power within the peak power adjustment range according to the set power adjustment amplitude.

[0025] In some possible embodiments, the voltage adjustment range and the power adjustment range are determined in the following manner:

[0026] Determine the maximum input voltage when the photovoltaic device is operating normally;

[0027] Determine the voltage adjustment range of the output voltage according to the maximum input voltage;

[0028] Determine the peak power adjustment range based on the specifications of the photovoltaic device.

[0029] In some possible embodiments, according to the wave generation parameters of the switching tubes using open-loop wave generation in the adjusted second-stage DC topology, determine the effective wave generation parameters when the output power of the photovoltaic cell simulation source reaches the peak power, including:

[0030] Monitor the output voltage of the first-stage DC topology in the photovoltaic device when switching to the MPPT mode;

[0031] If the difference between the output voltage of the first-stage DC topology and the set voltage is greater than the set threshold, adjust the wave generation parameters of the switching tubes using open-loop wave generation in the second-stage DC topology;

[0032] When it is determined that the difference is not greater than the set threshold, the current wave generation parameter is determined as the effective wave generation parameter when the output power of the photovoltaic cell simulation source reaches the peak power.

[0033] In some possible embodiments, curve fitting of the relationship function is performed based on the effective wave generation parameters corresponding to different updated output voltages, including:

[0034] Based on the effective wave generation parameters corresponding to different updated output voltages, when it is determined that the difference between the effective wave generation parameters corresponding to adjacent output voltages is greater than the set threshold, the adjacent output voltages are divided into different voltage segments;

[0035] Based on the effective wave generation parameters corresponding to different output voltages in each voltage segment, the relationship function between different output voltages and the effective wave generation parameters in this voltage segment is curve-fitted.

[0036] In some possible embodiments, curve fitting of the relationship function is performed based on the effective wave generation parameters corresponding to different updated output voltages, including:

[0037] Based on the effective wave generation parameters corresponding to different updated output voltages, corresponding weights are set for the effective wave generation parameters corresponding to different output voltages;

[0038] According to the set weights, curve fitting of the effective wave generation parameters corresponding to different output voltages is performed.

[0039] In some possible embodiments, after obtaining the mathematical model mapping the relationship between the output voltage and the effective wave generation parameter, it further includes:

[0040] When it is determined that the photovoltaic device for testing enters the MPPT mode, the current output voltage of the photovoltaic device for testing is collected;

[0041] According to the mathematical model, the effective wave generation parameter corresponding to the current output voltage is determined;

[0042] According to the determined effective wave generation parameter, control the second-stage DC topology in the photovoltaic device for testing to generate waves in an open-loop wave generation manner;

[0043] Detect the difference between the output voltage of the first-stage DC topology in the photovoltaic device for testing and the set voltage, and detect the peak power tracking accuracy of open-loop wave generation using the mathematical model according to the difference.

[0044] In some possible embodiments, the wave generation parameters of the adjusted open-loop wave generation include:

[0045] Wave generation frequency, wave generation variable duty ratio, or wave generation phase misalignment angle.

[0046] Second aspect, an embodiment of the present application provides a DC / DC wave generation method for a photovoltaic power supply device in the MPPT mode. The method includes:

[0047] When it is determined that the photovoltaic power supply device enters the MPPT mode, collect the current output voltage of the photovoltaic power supply device;

[0048] According to the mathematical model that maps the output voltage to the effective wave generation parameters provided by the first aspect above, determine the effective wave generation parameters corresponding to the current output voltage;

[0049] According to the effective wave generation parameters, the second-stage DC topology generates waves in an open-loop wave generation manner.

[0050] In some possible embodiments, the method further includes:

[0051] Determine the current output power according to the current output voltage and output current of the second-stage DC topology, or determine the current input power according to the current input voltage and input current of the first-stage DC topology;

[0052] Determining the effective wave generation parameters corresponding to the current output voltage according to the mathematical model that maps the output voltage to the effective wave generation parameters includes:

[0053] Determine the current input power segment where the current input power is located, or the current output power segment where the current output power is located. According to the mathematical model that maps the output voltage to the effective wave generation parameters under each input / output power segment, determine the effective wave generation parameters corresponding to the current input / output power segment.

[0054] Third aspect, another embodiment of the present application further provides a DC / DC wave generation device for an MPPT photovoltaic power supply device in the MPPT mode, including:

[0055] A simulation device construction module for constructing a photovoltaic cell simulation source;

[0056] A device parameter adjustment module for adjusting the output voltage of the second-stage DC topology in the photovoltaic device based on the photovoltaic cell simulation source, and adjusting the load power according to different peak powers of the photovoltaic cell simulation source to trigger the switch to the MPPT mode;

[0057] A wave generation parameter determination module for, when switching to the MPPT mode, determining the effective wave generation parameters when the output power of the photovoltaic cell simulation source reaches the peak power according to the wave generation parameters of the switching tube that uses open-loop wave generation in the adjusted second-stage DC topology;

[0058] A wave generation parameter fitting module, configured to fit the effective wave generation parameters corresponding to the same output voltage and different peak powers respectively, and update the fitted effective wave generation parameters to the effective wave generation parameters corresponding to the same output voltage;

[0059] A mathematical model construction module, configured to perform relationship function fitting based on the updated effective wave generation parameters corresponding to different output voltages respectively, to obtain a mathematical model that maps the relationship between the output voltage and the effective wave generation parameters, so as to determine the wave generation parameters of the DC / DC in the MPPT mode of the photovoltaic power supply device based on the mathematical model.

[0060] In a fourth aspect, an embodiment of the present application further provides a DC / DC wave generation device of a photovoltaic power supply device in the MPPT mode, including at least one processor; and a memory communicatively connected to the at least one processor; wherein, the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor, so that the at least one processor can execute any DC / DC wave generation method of the photovoltaic power supply device in the MPPT mode provided by the embodiment of the present application.

[0061] In a fifth aspect, an embodiment of the present application further provides a photovoltaic power supply device, including:

[0062] A photovoltaic cell;

[0063] A first-stage DC topology, connected to the photovoltaic cell, including an input voltage loop for controlling the input voltage of the first-stage DC topology and a bus voltage loop for controlling the output voltage of the first-stage DC topology;

[0064] A second-stage DC topology, connected to the first-stage DC topology, including a switching tube for controlling the output voltage, output current, and power;

[0065] An open-loop wave generation control module, connected to the switching tube of the second-stage DC topology, configured to collect the output voltage of the second-stage DC topology, obtain wave generation parameters by using the mathematical model constructed by the method provided in the first aspect above, and control the switching tube in the second-stage DC topology by using the wave generation parameters.

[0066] In a sixth aspect, another embodiment of the present application further provides a computer storage medium, where the computer storage medium stores a computer program, and the computer program is used to cause a computer to execute any DC / DC wave generation method of the photovoltaic power supply device in the MPPT mode provided by the embodiment of the present application.

[0067] The DC / DC wave generation method of the photovoltaic power supply device provided by the embodiment of the present application in the MPPT mode. The switching tubes in the second-stage DC topology of the photovoltaic power supply device adopt an open-loop wave generation method, and the wave generation parameters are obtained based on the pre-constructed mathematical model of DC / DC wave generation in the MPPT mode, which is beneficial to improving the smooth switching between the MPPT state and the non-MPPT state of the module, and can improve the stability of the module operating in the MPPT mode, as well as the maximum power point tracking speed and accuracy. This solves the problems existing in the existing control loop using full closed-loop control, which affect the tracking accuracy of the maximum power point, the stability of the power supply device operation, and reduce the reliability and service life of related devices.

[0068] Other features and advantages of the present application will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by implementing the present application. The objectives and other advantages of the present application can be achieved and obtained by the structures specifically pointed out in the written specification, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced below. Obviously, the drawings introduced below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0070] Figure 1 Schematic diagram of the structure of a photovoltaic DC-DC power supply device in the related art;

[0071] Figure 2 Schematic diagram of a PV curve showing the relationship between the output power and the open-circuit voltage of the photovoltaic cell simulation source of a photovoltaic DC-DC power supply device;

[0072] Figure 3 Flowchart of the DC / DC wave generation method of the photovoltaic power supply device in the MPPT mode according to an embodiment of the present disclosure;

[0073] Figure 4 Detailed flowchart diagram of the DC / DC wave generation method of the photovoltaic power supply device in the MPPT mode according to an embodiment of the present disclosure;

[0074] Figure 5 PV schematic diagram corresponding to different peak powers according to an embodiment of the present disclosure;

[0075] Figure 6a Function curve diagram of the wave generation frequency and the output voltage corresponding to the first voltage segment in the low power section according to an embodiment of the present disclosure;

[0076] Figure 6bFunction curve of the wave generation frequency corresponding to the second voltage segment in the low power segment and the output voltage according to an embodiment of the present disclosure;

[0077] Figure 7a Function curve of the wave generation frequency corresponding to the first voltage segment in the high power segment and the output voltage according to an embodiment of the present disclosure;

[0078] Figure 7b Function curve of the wave generation frequency corresponding to the second voltage segment in the high power segment and the output voltage according to an embodiment of the present disclosure;

[0079] Figure 8 Flowchart of the DC / DC wave generation method of the photovoltaic power supply device in the MPPT mode according to another embodiment of the present disclosure;

[0080] Figure 9a Schematic structural diagram of the photovoltaic power supply device according to an embodiment of the present disclosure;

[0081] Figure 9b Schematic structural diagram of the photovoltaic power supply device adopting the Boost+LLC module;

[0082] Figure 10 Schematic structural diagram of the DC / DC wave generation device of the photovoltaic power supply device in the MPPT mode according to an embodiment of the present disclosure;

[0083] Figure 11 Schematic structural diagram of the DC / DC wave generation device of the photovoltaic power supply device in the MPPT mode according to another embodiment of the present disclosure. Detailed implementation manners

[0084] To further illustrate the technical solutions provided by the embodiments of the present application, the following will be described in detail in combination with the accompanying drawings and specific implementation manners. Although the embodiments of the present application provide the method operation steps as shown in the following embodiments or drawings, more or fewer operation steps may be included in the method based on routine or non-creative labor. In the steps where there is no necessary causal relationship logically, the execution order of these steps is not limited to the execution order provided by the embodiments of the present application. When the method is actually processed or executed by the control device, it can be executed according to the method shown in the embodiments or drawings.

[0085] Such as Figure 1As shown in the figure, the photovoltaic DC-DC power supply device includes a photovoltaic cell, a first-stage DC topology, and a second-stage DC topology. Different lighting performances result in different peak powers output by the photovoltaic cell. The peak power of the photovoltaic cell fluctuates within a certain range under the influence of light and temperature. When the power of the load connected to the second-stage DC topology is greater than the output power of the photovoltaic cell, it triggers a switch to the MPPT mode, and the peak power tracking is performed by adjusting the switching tubes in the second-stage DC topology.

[0086] As Figure 2 shown, when the maximum open-circuit voltage Voc output by the photovoltaic cell is determined, if the light intensity and temperature are determined, then the peak power P mp output by the photovoltaic cell is determined. When the light intensity and the maximum open-circuit voltage Voc are determined, if the load power is not less than the peak power of the current photovoltaic cell, it will trigger the MPPT mode. At this time, it is necessary to adjust the switching tubes of the first-stage and second-stage DC topologies to change the output power of the photovoltaic cell simulation source and perform peak power tracking.

[0087] In view of the problems in the related technology that the control loop adopts a fully closed-loop control, which affects the tracking accuracy of the maximum power point, the stability of the power supply device operation, reduces the reliability and service life of related devices. This application proposes a photovoltaic power supply device, a DC / DC wave generation method and device under the MPPT mode, and a mathematical model construction method.

[0088] Other features and advantages of this application will be described in the subsequent specification, and part of them will become obvious from the specification, or be understood by implementing this application. The purpose and other advantages of this application can be realized and obtained through the structures specifically pointed out in the written specification, claims, and drawings.

[0089] The embodiment of this application provides a DC / DC wave generation method of a photovoltaic power supply device under the MPPT mode. The switching tubes of the second-stage DC topology of the photovoltaic power supply device adopt an open-loop wave generation method. In order to obtain the wave generation parameters for tracking the peak power, it is necessary to pre-construct a mathematical model that maps the relationship between different output voltages and effective wave generation parameters. During peak power tracking, the output voltage of the second-stage DC topology is collected, and the wave generation parameters are obtained by querying the mathematical model of DC / DC wave generation under the MPPT mode. As Figure 3 shown, the DC / DC wave generation method of the photovoltaic power supply device in the embodiment of this application under the MPPT mode includes:

[0090] Step 301, construct a photovoltaic cell simulation source;

[0091] In the process of constructing the mathematical model of DC / DC wave generation in MPPT mode, by virtually modeling photovoltaic cells with different lighting performances, photovoltaic cell simulation sources with different lighting performances are obtained. As mentioned above, under different lighting performances, the maximum open-circuit voltage and peak power of the corresponding photovoltaic cell simulation sources are different. The above lighting performances can include, but are not limited to, light intensity, light temperature, etc. For a photovoltaic cell simulation source, if the maximum open-circuit voltage is set, the output voltage fluctuates within a corresponding range, and the peak power also fluctuates within a corresponding range under the influence of lighting performance. The process of virtually modeling the photovoltaic cell can adopt the solutions of related technologies and will not be elaborated here.

[0092] Step 302: Based on the photovoltaic cell simulation source, adjust the output voltage of the second-stage DC topology in the photovoltaic device, and adjust the load power according to the different peak powers of the photovoltaic cell simulation source to trigger the switch to MPPT mode;

[0093] The first-stage DC topology structure of the photovoltaic device is the same as the prior art, that is, a DC buck-boost topology is adopted. The control loop includes an input voltage loop for controlling the input voltage of the first-stage DC topology and a bus voltage loop for controlling the output voltage of the first-stage DC topology. The input voltage of the first-stage DC topology is stably followed by the given input voltage through the input voltage loop, and the output voltage of the first-stage DC topology is stabilized at the given output voltage through the bus voltage loop. The wave generation method of the first-stage DC topology remains unchanged, and the wave generation method of related technologies can be used for wave generation, which will not be elaborated here.

[0094] The switching tubes in the second-stage DC topology structure of the photovoltaic device use an open-loop wave generation method for wave generation. The switching tubes are specifically used to adjust the output current and output voltage of the second-stage DC topology, affecting the output power of the photovoltaic cell simulation source. The connection position of the switching tubes in the second-stage DC topology is the prior art and will not be elaborated here.

[0095] When the power of the DC load is not less than the output power of the photovoltaic cell simulation source, trigger the switch to MPPT mode. In the embodiment of the present application, by adjusting the load power, the load power is made not less than the output power of the current photovoltaic cell simulation source, thereby triggering the entry into MPPT mode. For any photovoltaic cell simulation source, the peak power should fluctuate within the input power range where the corresponding photovoltaic device operates normally, so that the peak power adjustment range can be determined, and the load power can be adjusted to the peak power to trigger the entry into MPPT mode.

[0096] Step 303: When switching to MPPT mode, determine the effective wave generation parameters when the output power of the photovoltaic cell simulation source reaches the peak power according to the wave generation parameters of the switching tubes using open-loop wave generation in the adjusted second-stage DC topology;

[0097] When entering the MPPT mode, the wave generation parameters of the switching tubes of the second-stage DC topology that enable the photovoltaic cell simulation source to reach the peak power are related to the output voltage. To obtain the wave generation parameters that enable the output power of the photovoltaic cell simulation source to reach the peak power for the current output voltage, it is necessary to continuously adjust the wave generation parameters and check whether the peak power is tracked.

[0098] The wave generation parameters of the open-loop wave generation adjusted in this embodiment include, but are not limited to, the wave generation frequency, the wave generation variable duty cycle, or the wave generation phase misalignment angle, or a combination thereof. Specifically, it can be any one of the wave generation parameters. The adjustment method can be to set a given value that will not prevent the device from starting and driving the load under the current working conditions and has fault protection. Based on the given value, continuously adjust the wave generation parameters until the output power of the photovoltaic cell simulation source reaches the peak power.

[0099] In this embodiment, according to the wave generation parameters of the switching tubes that adopt open-loop wave generation in the adjusted second-stage DC topology, determining the effective wave generation parameters when the output power of the photovoltaic cell simulation source reaches the peak power includes:

[0100] Monitor the output voltage of the first-stage DC topology in the photovoltaic device when switching the MPPT mode;

[0101] If the difference between the output voltage of the first-stage DC topology and the set voltage is greater than the set threshold, adjust the wave generation parameters of the switching tubes that adopt open-loop wave generation in the second-stage DC topology;

[0102] When it is determined that the difference is not greater than the set threshold, determine the current wave generation parameters as the effective wave generation parameters when the output power of the photovoltaic cell simulation source reaches the peak power.

[0103] The above set voltage should enable the photovoltaic device to work properly under various working conditions, and there is a certain margin considering device errors.

[0104] If the output voltage of the first-stage DC topology is close to the set voltage and the output power of the photovoltaic cell simulation source reaches the peak power, the current wave generation parameters are also the effective wave generation parameters.

[0105] Step 304, fit the effective wave generation parameters corresponding to the same output voltage and different peak powers respectively, and update the fitted effective wave generation parameters as the effective wave generation parameters corresponding to the same output voltage;

[0106] Step 305, perform a relationship function fitting based on the updated effective wave generation parameters corresponding to different output voltages respectively, to obtain a mathematical model that maps the relationship between the output voltage and the effective wave generation parameters, so as to determine the wave generation parameters of the DC / DC in the photovoltaic power supply device in the MPPT mode based on the mathematical model.

[0107] In the embodiment of the present application, the photovoltaic cell simulation source is used to simulate the output of photovoltaic cells with different light performance, and the wave generation parameters corresponding to different output voltages of the photovoltaic device when reaching different peak powers are obtained. Since the wave generation parameters are directly related to the output voltage, the output voltage is used as the input variable and the wave generation parameters are used as the output variables. In order to obtain the relationship function between the output variable and the input variable, the effective wave generation parameters corresponding to the same output voltage and different peak powers are fitted to obtain a fitted effective wave generation parameter, and the fitted effective wave generation parameter is updated as the effective wave generation parameter corresponding to the same output voltage. Based on the updated effective wave generation parameters corresponding to different output voltages, a relationship function is fitted to obtain a mathematical model mapping the output voltage and the effective wave generation parameters, so as to determine the wave generation parameters of the DC / DC in the MPPT mode of the photovoltaic power supply device based on the mathematical model.

[0108] When fitting the effective wave generation parameters corresponding to the same output voltage and different peak powers into one effective wave generation parameter, it involves fitting multiple obtained effective wave generation parameters under the same input voltage. In the embodiment of the present application, when fitting, the fluctuation range of multiple effective wave generation parameters will be judged. If the fluctuation range is within the set range, it is considered to meet the fitting requirements, otherwise it is considered not to meet the fitting requirements.

[0109] In the implementation process, one factor affecting whether the fitting requirements are met is the output power of the second-level DC topology or the input power of the first-level DC topology. In the embodiment of the present application, after determining the effective wave generation parameters when the output power of the photovoltaic cell simulation source reaches the peak power, it further includes:

[0110] Determine the output power according to the current output voltage and output current of the second-level DC topology, or determine the input power according to the current input voltage and input current of the first-level DC topology in the photovoltaic device.

[0111] The fitting of the effective wave generation parameters corresponding to the same output voltage and different peak powers in this embodiment includes:

[0112] When it is determined that the different effective wave generation parameters corresponding to the same output voltage and different peak powers do not meet the fitting requirements, the corresponding input power or output power is segmented, and the different effective wave generation parameters corresponding to the same output voltage and different peak powers in the same input / output power segment meet the fitting requirements;

[0113] Fit the different effective wave generation parameters corresponding to the same output voltage and different peak powers in the same input / output power segment into one effective wave generation parameter;

[0114] Based on the updated effective wave generation parameters corresponding to different output voltages, a relationship function is fitted to obtain a mathematical model mapping the output voltage and the effective wave generation parameters, including:

[0115] For the updated effective wave generation parameters corresponding to different output voltages under the same input / output power range, perform a relational function fitting to obtain a mathematical model that maps the output voltage to the effective wave generation parameters under each input / output power range.

[0116] In this way, for the same output voltage, if the input / output power segments where the corresponding input / output power is located are different, the mathematical models of the relationship between the mapped output voltage and the effective wave generation parameters are different.

[0117] The voltage adjustment range and power adjustment range of the embodiments of the present application are determined in the following manner: determine the maximum input voltage when the photovoltaic device operates normally; determine the voltage adjustment range of the output voltage according to the maximum input voltage; determine the peak power adjustment range based on the specifications of the photovoltaic device. The specific determination method can be determined using the prior art according to the relevant parameters of the circuit and will not be elaborated in detail here.

[0118] As described above, in order to obtain the sampling points of the input variables and output variables, the embodiments of the present application continuously change the output voltage and peak power to obtain as many sampling points as possible. Each time it triggers and enters the MPPT mode, it can be understood as one sampling. In this embodiment, different output voltages are adjusted for the second-stage DC topology in the photovoltaic device, and the load power is adjusted according to the different peak powers of the photovoltaic cell simulation source to trigger the switching to the MPPT mode, including:

[0119] Adjust the load power to a peak power and keep it unchanged, and perform a round of output voltage adjustment based on the voltage adjustment range of the output voltage;

[0120] Each time the output voltage is adjusted, trigger a switch to the MPPT mode;

[0121] When it is determined that a round of adjustment of the load power is not completed after each round of output voltage adjustment, perform an adjustment of the load power and trigger the next round of output voltage adjustment;

[0122] Among them, a round of output voltage adjustment is completed by increasing or decreasing the output voltage within the voltage adjustment range according to the set voltage adjustment amplitude, and a round of load power adjustment is completed by increasing or decreasing the load power within the peak power adjustment range according to the set power adjustment amplitude.

[0123] By continuously adjusting the peak power within the peak power adjustment range according to the set power adjustment amplitude, and adjusting the output voltage within the voltage adjustment range according to the set voltage adjustment amplitude, sampling at the sampling points can be achieved. When adjusting the peak power, it can be adjusted from the minimum value to the maximum value, or from the maximum value to the minimum value. The output voltage adjustment can be adjusted from the minimum value to the maximum value, or from the maximum value to the minimum value. The specific adjustment method is not limited to this, and it can also be adjusted from any peak power and any output voltage. In addition, in the above method, the output voltage is adjusted first, and after completing one round of output voltage adjustment, the load power is adjusted. It is also possible to adjust the load power first, and after completing one round of load power adjustment, then adjust the output voltage.

[0124] The following gives the specific process of first adjusting the output voltage and then adjusting the load power after completing one round of output voltage adjustment, which specifically includes:

[0125] Step 1, set the maximum open-circuit voltage V of the photovoltaic cell simulation source oc_max , the maximum open-circuit voltage V oc_max The setting should be based on the maximum input voltage of the photovoltaic device. Then set the peak power on the output power curve of the photovoltaic cell simulation source to P mp_min , P mp_min is the minimum input power that satisfies the normal operation of the photovoltaic device. Adjust the load power to be equal to P mp_min , so that the MPPT mode can be triggered after power-on.

[0126] Step 2.1, power on and start the photovoltaic cell simulation source. Before loading, adjust the output voltage of the photovoltaic device to the lowest output voltage within the voltage adjustment range through the controller of the photovoltaic cell simulation source Vo_min , then set a suitable given value of the wave generation parameter for open-loop wave generation for the switching tube in the second-stage DC topology, and then load.

[0127] Step 2.2, after loading, trigger to enter the MPPT mode, monitor the bus voltage V of the first-stage DC topology bus , and judge the difference between V bus and a certain set voltage V bus_set . If the difference is large, adjust the wave generation parameter of the switching tube in the second-stage DC topology through the controller of the photovoltaic cell simulation source until V bus = V bus_set or when the two are relatively close, it is determined that the peak power is tracked, and record the current wave generation parameter of the second-stage DC topology, the input voltage V of the first-stage DC topology in or the output voltage V of the second-stage DC topology o , and the input current I of the first-stage DC topology in or the output current I of the second-stage DC topologyo , the input power P is calculated in or the output power P o .

[0128] The above V bus_se The setting of t needs to consider that the module can work normally under test conditions and actual working conditions. At the same time, on this basis, the difference in V caused by the parameter error of the device should also be considered as a margin bus .

[0129] Step 2.3, adjust the output voltage of the photovoltaic device, that is, the output voltage of the second-stage DC topology, to V o_min +ΔV step , and repeat Step 2.1 and Step 2.2 until V o_min +ΔV step is equal to the maximum output voltage V within the voltage adjustment range o_max ;

[0130] The above ΔV step is set according to the required peak power tracking accuracy. The smaller ΔV step , the higher the peak power tracking accuracy

[0131] Step 2.4, adjust the peak power on the output power curve of the photovoltaic cell simulation source to P mp_min +ΔP step , and repeat Step 2.1 to Step 2.3 until P mp_min +ΔP step is equal to the maximum value P of the peak power adjustment range mp_max , that is, P mp_min +ΔP step =P mp_max .

[0132] The above P step is set according to the required peak power tracking accuracy. The smaller P step , the higher the peak power tracking accuracy

[0133] Based on the above process, the acquisition of sampling points can be completed. Analyze and process the obtained sampling point data, fit multiple sampling points corresponding to the same output voltage into one sampling point, and perform curve fitting on the output voltage and the wave generation parameters based on the fitted sampling points to obtain the corresponding relationship function. Due to certain limitations in the wave generation of the switching tubes in the second-stage DC topology, for the same wave generation parameters, the bus voltage shows different performances under different input or output powers. Therefore, during the fitting process, power segmentation can be performed based on the above method, and curve fitting is performed based on the sampling points in different power segments. In addition, during the curve fitting process, if it is found that there are significant changes in the effective wave generation parameters corresponding to the fitting before and after a certain output voltage, in order to make the mathematical model more accurately reflect the real situation, the output voltage can be segmented for curve fitting processing.

[0134] This embodiment performs relationship function fitting based on the effective wave generation parameters corresponding to different updated output voltages, including:

[0135] Based on the effective wave generation parameters corresponding to different updated output voltages, when it is determined that the difference between the effective wave generation parameters corresponding to adjacent output voltages is greater than the set threshold, the adjacent output voltages are divided into different voltage segments;

[0136] Based on the effective wave generation parameters corresponding to different output voltages in each voltage segment, fit the relationship function between different output voltages and effective wave generation parameters in this voltage segment.

[0137] By performing curve fitting on the input / output power segmentation and output voltage segmentation, it is possible to prevent sudden changes in the wave generation parameters during working condition changes, which may cause sudden changes in the current or voltage within the two-stage DC topology, affecting the current or voltage stress of the switching tubes and the stable operation of the equipment.

[0138] In the process of the above curve fitting in this application embodiment, in order to make the wave generation parameters corresponding to a certain output voltage more accurate, weighted processing can be considered. Relationship function fitting is performed based on the effective wave generation parameters corresponding to different updated output voltages, including:

[0139] Based on the effective wave generation parameters corresponding to different updated output voltages, set corresponding weights for the effective wave generation parameters corresponding to different output voltages;

[0140] According to the set weights, perform relationship function fitting on the effective wave generation parameters corresponding to different output voltages.

[0141] In order to verify the tracking accuracy of the peak power of the constructed mathematical model, after obtaining the mathematical model that maps the output voltage and the effective wave generation parameters in this embodiment, it further includes:

[0142] When it is determined that the photovoltaic device for testing enters the MPPT mode, collect the current output voltage of the photovoltaic device for testing;

[0143] According to the mathematical model, determine the effective wave generation parameter corresponding to the current output voltage;

[0144] According to the determined effective wave generation parameter, control the second-stage DC topology in the photovoltaic device for testing to generate waves in an open-loop wave generation manner;

[0145] Detect the difference between the output voltage of the first-stage DC topology in the photovoltaic device for testing and the set voltage, and detect the peak power tracking accuracy of open-loop wave generation using the mathematical model according to the difference.

[0146] If the difference between the output voltage of the first-stage DC topology and the set voltage, it is considered that the tracking accuracy meets the requirements.

[0147] Taking the topology of the photovoltaic power supply device as the Boost+LLC (resonant converter) module as an example, the following gives the specific DC / DC wave generation method flow of the photovoltaic power supply device in the MPPT mode, as Figure 4 shown, specifically including:

[0148] Step 400, in the Boost+LLC software, set the wave generation method of the switching tube in the LLC module to open-loop wave generation, and control the wave generation frequency of the switching tube in the LLC module through the host computer. Since there is a certain relationship between the wave generation duty cycle and the wave generation frequency, the host computer can only adjust the wave generation frequency to achieve the synchronous change of the wave generation frequency and the duty cycle of the switching tube in the LLC module;

[0149] Step 401, set the maximum open-circuit voltage V oc_max of the photovoltaic cell simulation source, the load power P mp Adopt the lowest peak power P mp_min , the PV curve of the lowest peak power P mp_min is specifically as Figure 5 shown, for example, V oc_max =400V, P mp_min =350w;

[0150] Step 402, the analog DC load selects the CV (Constant Voltage) mode, and adjusts the output voltage of the photovoltaic power supply device to the lowest output voltage V o_min , for example, V o_min is 38V;

[0151] Step 403, power on and start the photovoltaic cell simulation source, but the switching tube in the LLC module does not generate waves;

[0152] Step 404, before the photovoltaic cell simulation source is loaded, set the wave generation frequency for the switching tubes in the LLC module through the background host computer to adopt the maximum wave generation frequency f llc_max ;

[0153] Step 405, connect the load in CV mode, that is, connect the DC load. Since the load power of the DC load is adjusted to the peak power, trigger to enter the MPPT mode;

[0154] Step 406, set the given bus voltage V bus_set of the first-stage DC topology, for example, V bus_set = 400V;

[0155] Step 407, adjust the wave generation frequency of the switching tubes in the LLC module and monitor the bus voltage V bus of the first-stage DC topology;

[0156] If V bus is greater than V bus_set , then appropriately reduce the wave generation frequency f llc of the switching tubes in the LLC module through the host computer control until V bus = 400V or is close to 400V.

[0157] Step 408, determine whether the difference between V bus and V bus_set is less than the set threshold. If so, execute Step 409; otherwise, return to execute Step 407;

[0158] Step 409, record the wave generation frequency f llc , output voltage V o , output current I o , and calculate the output power P o , and power down the photovoltaic cell simulation source;

[0159] Step 410, determine whether the output voltage V o reaches the maximum output voltage V o_max , for example, V o_max is 58V. If so, execute Step 412; otherwise, execute Step 411;

[0160] Step 411, adjust the output voltage V o to V o + ΔV step , where ΔV step = 2V, and return to Step 403;

[0161] Step 412, determine whether the load power P mp is adjusted to the maximum peak power P mp_max , for example, P mp_maxis 4000W. If step 414 is executed, otherwise step 413 is executed;

[0162] Step 413: Adjust the load power P of the photovoltaic cell simulation source mp to P mp +ΔP step , as specifically shown in Figure 5 the PV curve shown. Here, ΔP step = 200W, and return to step 402;

[0163] Step 414: After processing the data recorded in step 409, perform curve fitting to obtain a mathematical model for determining the wave generation parameters of the DC / DC in the MPPT mode of the photovoltaic power supply device for subsequent wave generation.

[0164] Specifically, the wave generation frequencies corresponding to different output voltages can be weighted and curve fitting can be performed to obtain a relationship function. During the curve fitting process, the input / output power can be segmented according to the above implementation manner to obtain the relationship function expression of f llc with respect to V o under different input or output power segments. For example, Figure 6a and Figure 6b are the curves fitted in the low power segment, and Figure 7a and Figure 7b are the curves fitted in the high power segment.

[0165] During the curve fitting process, it is found that the f llc corresponding to the output voltage before and after 52V changes greatly, and the curve fitted in this way will deviate greatly from the test points. Therefore, the curve is divided into two segments for fitting. For the low power segment, as shown in Figure 6a , a curve is fitted for the output voltage less than 52V, and as shown in Figure 6b , another curve is fitted for the output voltage greater than or equal to 52V. For the high power segment, as shown in Figure 7a , a curve is fitted for the output voltage less than 52V, and as shown in Figure 7b , another curve is fitted for the output voltage greater than or equal to 52V. In this way, the fitted curve is found to be more accurate after back-calculating and verifying the test point data.

[0166] After the curve fitting in the embodiment of the present application is completed, a mathematical model for DC / DC wave generation in the MPPT mode is obtained. The photovoltaic device is tested under different output voltages P mp and different output voltage conditions. During the test, observe whether the working point on the photovoltaic cell simulation source is stable and whether the maximum power point tracking accuracy meets the requirements. Check whether the input voltage of the first-stage DC topology has oscillations and whether the bus voltage is close to 400V through the oscilloscope, so as to determine the tracking accuracy of the peak power.

[0167] In the embodiments of the present application, for the switching of different output power segments and the switching of different output voltage segments V o resulting in a large change in f llc at the points with large changes, a gradual change processing of the wave - generating frequency is performed. For example, when switching from one working state to another, if f llc needs to be switched from 70 kHz to 120 kHz, during the switching process, the speed of switching from 70 kHz to 120 kHz needs to be slowed down instead of suddenly changing from 70 kHz to 120 kHz.

[0168] After the above - mentioned process, through tests under various working conditions, the maximum power point tracking accuracy is above 99.5%, and it can operate stably for a long time.

[0169] Based on the same inventive concept, the embodiments of the present application provide a DC / DC wave - generating method for a photovoltaic power supply device in the MPPT mode, as Figure 8 shown, the method includes:

[0170] Step 801, when it is determined that the photovoltaic power supply device enters the MPPT mode, collect the current output voltage of the photovoltaic power supply device;

[0171] Step 802, according to the mathematical model that maps the relationship between the output voltage and the effective wave - generating parameters constructed by the above - mentioned method, determine the effective wave - generating parameters corresponding to the current output voltage;

[0172] Step 803, according to the effective wave - generating parameters, the second - stage DC topology performs wave - generating in an open - loop wave - generating manner.

[0173] In one or more possible embodiments, the method further includes:

[0174] Determine the current output power according to the current output voltage and output current of the second - stage DC topology, or determine the current input power according to the current input voltage and input current of the first - stage DC topology;

[0175] Determining the effective wave - generating parameters corresponding to the current output voltage according to the mathematical model that maps the relationship between the output voltage and the effective wave - generating parameters includes:

[0176] Determine the current input power segment where the current input power is located, or the current output power segment where the current output power is located. According to the mathematical model that maps the relationship between the output voltage and the effective wave - generating parameters in each input / output power segment, determine the effective wave - generating parameters corresponding to the current input / output power segment.

[0177] Under different working conditions, after the power supply module enters the MPPT mode, the second-stage DC topology is equivalent to a converter with a fixed turns ratio, which is determined by the gain coefficient corresponding to the wave generation of the current second-stage DC topology and the transformer's own turns ratio. And this gain coefficient is determined by the current input and output powers and the output voltage. These two variables are relatively stable in the photovoltaic scenario, making the control simpler and the tracking of the maximum power point more stable.

[0178] The embodiment of the present application differentiates the wave generation modes of the second-stage DC topology of the photovoltaic power supply device in the MPPT mode and the non-MPPT mode. In the MPPT mode, the device reads variables (output voltage, input power, or output power) and generates waves according to the given mathematical model of DC / DC wave generation in the MPPT mode, making its maximum power point tracking accuracy and working efficiency higher.

[0179] The mathematical model of DC / DC wave generation in the MPPT mode of the embodiment of the present application is constructed by actual experimental tests, data analysis, and processing. The test sequence and step size can be changed according to the specifications and parameter accuracy requirements of the photovoltaic power supply device during the experimental test process. At the same time, various methods can be used for the data analysis and processing of the experimental results, and the errors that occur can be corrected to an acceptable range according to the actual working conditions in a timely manner, making the constructed mathematical model of DC / DC wave generation in the MPPT mode more accurate.

[0180] After the above-mentioned mathematical model of DC / DC wave generation in the MPPT mode is determined, a slow change strategy for the wave generation of the second-stage DC topology is added to make the photovoltaic DC-DC power supply device work more stably; through the above combination, the final wave generation strategy of the second-stage DC topology can effectively solve the deficiencies of using control loop closed-loop wave generation in the related art.

[0181] Based on the same inventive concept, the embodiment of the present application provides a photovoltaic power supply device, as Figure 9a shown, including:

[0182] A photovoltaic cell 901;

[0183] A first-stage DC topology 902, connected to the photovoltaic cell 901, including an input voltage loop for controlling the input voltage of the first-stage DC topology and a bus voltage loop for controlling the output voltage of the first-stage DC topology;

[0184] A second-stage DC topology 903, connected to the first-stage DC topology 902, including a switching tube 904 for controlling the output voltage, output current, and power;

[0185] The open-loop wave generation control module 905 is connected to the switching tubes of the second-stage DC topology, and is used to collect the output voltage of the second-stage DC topology, obtain the wave generation parameters by using the mathematical model of DC / DC wave generation in the MPPT mode constructed by the method provided in the above embodiment, and control the switching tubes in the second-stage DC topology by using the wave generation parameters.

[0186] As Figure 9b shown in the structural schematic diagram of a photovoltaic power supply device adopting a Boost+LLC module, where the input voltage Vin of the Boost module is sampled and compared with the given voltage Vinref, and the Boost driver uses a closed-loop control method according to the difference to control the switching tubes in the Boost module. The circuit of the Boost module and its switching tubes is of an existing structure and will not be elaborated here. For the LLC module, the open-loop wave generation control module includes a mathematical model curve calculation module and an LCC driver. Among them, the sampled output voltage Vo and output current Io are used for power calculation, and the calculated output power and the sampled Vo are input into the mathematical model curve calculation module to query the mathematical model of DC / DC wave generation in the MPPT mode to obtain the wave generation parameters. The obtained wave generation parameters are input into the LCC driver, and the LCC driver uses the wave generation parameters to control the switching tubes in the LLC module in an open-loop manner. As Figure 9b the circuit of the LLC module and its switching tubes in is of an existing structure and will not be elaborated here.

[0187] Based on the same inventive concept, the present application also provides a DC / DC wave generation device 100 of a photovoltaic power supply device in the MPPT mode, as Figure 10 shown, the device includes:

[0188] An analog device construction module 101, configured to construct a photovoltaic cell simulation source;

[0189] A device parameter adjustment module 102, configured to adjust different output voltages of the second-stage DC topology in the photovoltaic device based on the photovoltaic cell simulation source, and adjust the load power according to different peak powers of the photovoltaic cell simulation source to trigger a switch to the MPPT mode;

[0190] A wave generation parameter determination module 103, configured to, when switching to the MPPT mode, determine the effective wave generation parameters when the output power of the photovoltaic cell simulation source reaches the peak power according to the wave generation parameters of the switching tubes adopting open-loop wave generation in the adjusted second-stage DC topology;

[0191] A wave generation parameter fitting module 104, configured to fit the effective wave generation parameters corresponding to the same output voltage and different peak powers respectively, and update the fitted effective wave generation parameters to the effective wave generation parameters corresponding to the same output voltage;

[0192] The mathematical model construction module 105 is configured to perform relationship function fitting based on the effective wave generation parameters corresponding to different updated output voltages, obtain a mathematical model mapping the output voltage and the effective wave generation parameters, and determine the wave generation parameters of the DC / DC in the photovoltaic power supply device in the MPPT mode based on the mathematical model.

[0193] In some possible embodiments, after the wave generation parameter determination module determines the effective wave generation parameters when the output power of the photovoltaic cell simulation source reaches the peak power, it is further configured to:

[0194] Determine the output power according to the current output voltage and output current of the second-stage DC topology, or determine the input power according to the current input voltage and input current of the first-stage DC topology in the photovoltaic device;

[0195] The wave generation parameter fitting module fits the effective wave generation parameters corresponding to the same output voltage and different peak powers, including:

[0196] When it is determined that the different effective wave generation parameters corresponding to the same output voltage and different peak powers do not meet the fitting requirements, segment the corresponding input power or output power, and the different effective wave generation parameters corresponding to the same output voltage and different peak powers in the same input / output power segment meet the fitting requirements;

[0197] Fit the different effective wave generation parameters corresponding to the same output voltage and different peak powers in the same input / output power segment into one effective wave generation parameter;

[0198] The mathematical model construction module performs relationship function fitting based on the effective wave generation parameters corresponding to different updated output voltages, and obtains a mathematical model mapping the output voltage and the effective wave generation parameters, including:

[0199] Perform relationship function fitting on the effective wave generation parameters corresponding to different updated output voltages in the same input / output power segment, and obtain a mathematical model mapping the output voltage and the effective wave generation parameters in each input / output power segment.

[0200] As a possible embodiment, the device parameter adjustment module adjusts the output voltages output by the second-stage DC topology in the photovoltaic device, and adjusts the load power according to the different peak powers of the photovoltaic cell simulation source to trigger a switch to the MPPT mode, including:

[0201] Adjust the load power to a peak power and keep it unchanged, and perform a round of output voltage adjustment based on the voltage adjustment range of the output voltage;

[0202] Trigger a switch to the MPPT mode every time the output voltage is adjusted;

[0203] After each round of output voltage adjustment is completed, when it is determined that a round of load power adjustment has not been completed, perform a round of load power adjustment and trigger the next round of output voltage adjustment;

[0204] Among them, one round of output voltage adjustment is completed by increasing or decreasing the output voltage within the voltage adjustment range according to the set voltage adjustment amplitude, and one round of load power adjustment is completed by increasing or decreasing the load power within the peak power adjustment range according to the set power adjustment amplitude.

[0205] In one or more possible embodiments, the voltage adjustment range and the power adjustment range are determined in the following manner:

[0206] Determine the maximum input voltage when the photovoltaic device is operating normally;

[0207] Determine the voltage adjustment range of the output voltage according to the maximum input voltage;

[0208] Determine the peak power adjustment range based on the specifications of the photovoltaic device.

[0209] In one or more possible embodiments, the wave generation parameter determination module determines the effective wave generation parameters when the output power of the photovoltaic cell simulation source reaches the peak power according to the wave generation parameters of the switching tubes that adopt open-loop wave generation in the adjusted second-stage DC topology, including:

[0210] Monitor the output voltage of the first-stage DC topology in the photovoltaic device when switching the MPPT mode;

[0211] If the difference between the output voltage of the first-stage DC topology and the set voltage is greater than the set threshold, adjust the wave generation parameters of the switching tubes that adopt open-loop wave generation in the second-stage DC topology;

[0212] When it is determined that the difference is not greater than the set threshold, determine the current wave generation parameters as the effective wave generation parameters when the output power of the photovoltaic cell simulation source reaches the peak power.

[0213] In one or more possible embodiments, the mathematical model construction module performs relationship function fitting based on the updated effective wave generation parameters corresponding to different output voltages, including:

[0214] Based on the updated effective wave generation parameters corresponding to different output voltages, when it is determined that the difference between the effective wave generation parameters corresponding to adjacent output voltages is greater than the set threshold, divide the adjacent output voltages into different voltage segments;

[0215] Based on the effective wave generation parameters corresponding to different output voltages in each voltage segment, fit the relationship function between different output voltages and effective wave generation parameters in this voltage segment.

[0216] In one or more possible embodiments, the mathematical model construction module performs relationship function fitting based on the updated effective wave generation parameters corresponding to different output voltages, including:

[0217] Based on the updated effective wave generation parameters corresponding to different output voltages, set corresponding weights for the effective wave generation parameters corresponding to different output voltages;

[0218] According to the set weights, perform relationship function fitting on the effective wave generation parameters corresponding to different output voltages.

[0219] In one or more possible embodiments, after the mathematical model construction module obtains the mathematical model mapping the relationship between the output voltage and the effective wave generation parameters, it is further used for:

[0220] When it is determined that the photovoltaic device for testing enters the MPPT mode, collect the current output voltage of the photovoltaic device for testing;

[0221] According to the mathematical model, determine the effective wave generation parameters corresponding to the current output voltage;

[0222] According to the determined effective wave generation parameters, control the second - stage DC topology in the photovoltaic device for testing to generate waves in an open - loop wave generation manner;

[0223] Detect the difference between the output voltage of the first - stage DC topology in the photovoltaic device for testing and the set voltage, and detect the peak power tracking accuracy of the open - loop wave generation using the mathematical model according to the difference.

[0224] In one or more possible embodiments, the wave generation parameters of the adjusted open - loop wave generation include:

[0225] Wave generation frequency, wave generation variable duty cycle, or wave generation phase - shift angle.

[0226] After introducing the DC / DC wave generation method and device of the photovoltaic power supply device in the MPPT mode according to the exemplary embodiments of the present application, next, the DC / DC wave generation device of the photovoltaic power supply device in the MPPT mode according to another exemplary embodiment of the present application is introduced.

[0227] Those skilled in the art can understand that various aspects of the present application can be implemented as a system, a method, or a program product. Therefore, various aspects of the present application can be specifically implemented in the following forms, namely: a complete hardware implementation, a complete software implementation (including firmware, microcode, etc.), or an implementation combining hardware and software aspects, which can be collectively referred to as "circuit", "module", or "system" here.

[0228] In some possible embodiments, the DC / DC wave generating device of the photovoltaic power supply device according to the present application in the MPPT mode may include at least one processor and at least one memory. Among them, the memory stores program codes, and when the program codes are executed by the processor, the processor executes the steps in the DC / DC wave generating method of the photovoltaic power supply device according to various exemplary embodiments of the present application described above in this specification.

[0229] The following will refer to Figure 11 to describe the DC / DC wave generating device 110 of the photovoltaic power supply device in the MPPT mode according to this embodiment of the present application. Figure 11 The shown DC / DC wave generating device 110 of the photovoltaic power supply device in the MPPT mode is only an example and should not bring any limitation to the functions and usage scope of the embodiments of the present application.

[0230] As Figure 11 shown, the DC / DC wave generating device 110 of the photovoltaic power supply device in the MPPT mode is presented in the form of a general electronic device. The components of the DC / DC wave generating device 110 of the photovoltaic power supply device in the MPPT mode may include but are not limited to: the above-mentioned at least one processor 111, the above-mentioned at least one memory 112, and a bus 113 connecting different system components (including the memory 112 and the processor 111).

[0231] The bus 113 represents one or more of several types of bus structures, including a memory bus or a memory controller, a peripheral bus, a processor, or a local bus using any bus structure in a variety of bus structures.

[0232] The memory 112 may include a readable medium in the form of a volatile memory, such as a random access memory (RAM) 1121 and / or a cache memory 1122, and may further include a read-only memory (ROM) 1123.

[0233] The memory 112 may further include a program / utility 1125 having a set (at least one) of program modules 1124. Such program modules 1124 include but are not limited to: an operating system, one or more application programs, other program modules, and program data. The implementation of a network environment may be included in each or some combination of these examples.

[0234] The DC / DC wave generation device 110 of the photovoltaic power supply device in the MPPT mode can also communicate with one or more external devices 114 (such as keyboards, pointing devices, etc.), and can also communicate with one or more devices that enable users to interact with the mathematical model construction device 130 for wave generation in the MPPT mode of the DC / DC, and / or communicate with any device (such as routers, modems, etc.) that enables the DC / DC wave generation device 110 of the photovoltaic power supply device to communicate with one or more other electronic devices in the MPPT mode. Such communication can be carried out through the input / output (I / O) interface 115. Moreover, the DC / DC wave generation device 110 of the photovoltaic power supply device in the MPPT mode can also communicate with one or more networks (such as local area networks (LANs), wide area networks (WANs), and / or public networks, such as the Internet) through the network adapter 116. As shown in the figure, the network adapter 116 communicates with other modules for the DC / DC wave generation device 110 of the photovoltaic power supply device in the MPPT mode through the bus 113. It should be understood that although not shown in the figure, other hardware and / or software modules can be combined with the DC / DC wave generation device 110 of the photovoltaic power supply device in the MPPT mode, including but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID systems, tape drives, and data backup storage systems, etc.

[0235] In some possible implementation manners, various aspects of a DC / DC wave generation method for a photovoltaic power supply device in the MPPT mode provided by the present application can also be implemented in the form of a program product, which includes program code. When the program product runs on a computer device, the program code is used to cause the computer device to execute the steps of a DC / DC wave generation method for a photovoltaic power supply device according to various exemplary embodiments described above in this specification.

[0236] The program product can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples (non-exhaustive list) of the readable storage medium include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0237] A program product for DC / DC commutation of a photovoltaic power supply device in the MPPT mode according to an embodiment of the present application may be a portable compact disc read-only memory (CD-ROM) and include program code, and may run on an electronic device. However, the program product of the present application is not limited thereto. In this document, a readable storage medium may be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0238] A readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, in which the readable program code is carried. Such a propagated data signal may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the foregoing. A readable signal medium may also be any readable medium other than a readable storage medium, which can send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0239] The program code contained on a readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wired, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0240] The program code for performing the operations of the present application may be written in any combination of one or more programming languages, including object-oriented programming languages such as Java, C++, etc., and also including conventional procedural programming languages such as the "C" language or similar programming languages. The program code may be executed entirely on the user's electronic device, partially on the user's device, executed as a stand-alone software package, partially on the user's electronic device and partially on a remote electronic device, or entirely on a remote electronic device or server. In the case of a remote electronic device, the remote electronic device may be connected to the user's electronic device through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external electronic device (e.g., connected through the Internet using an Internet service provider).

[0241] It should be noted that although several units or subunits of the apparatus are mentioned in the above detailed description, such a division is merely exemplary and not mandatory. In fact, according to the embodiments of the present application, the features and functions of the two or more units described above may be embodied in one unit. Conversely, the features and functions of one unit described above may be further divided and embodied by multiple units.

[0242] In addition, although the operations of the method of the present application are described in a specific order in the drawings, this does not require or imply that these operations must be performed in that specific order, or that all of the shown operations must be performed to achieve the desired result. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step for execution, and / or one step may be decomposed into multiple steps for execution.

[0243] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memory, CD-ROM, optical memory, etc.) that contain computer-usable program code.

[0244] The present application is described with reference to the flowcharts and block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and block diagrams, as well as the combination of flows and blocks in the flowcharts and block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processors of general-purpose computers, special-purpose computers, embedded processors, or other programmable data processing devices to generate a machine, such that the instructions executed by the processors of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one or more of the flows Figure 1 or blocks.

[0245] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including instruction means that implement the functions specified in Figure 1 one or more of the flows Figure 1 or blocks.

[0246] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are performed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one or more of the flows Figure 1 or blocks.

[0247] Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications once they learn the basic creative concepts. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present application.

[0248] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims

1. A DC / DC wave generation method for a photovoltaic power supply device in MPPT mode, characterized in that, The method includes: Constructing a photovoltaic cell simulation source; Based on the photovoltaic cell simulation source, adjusting the output voltage of the second-stage DC topology in the photovoltaic device, and adjusting the load power according to different peak powers of the photovoltaic cell simulation source to trigger a switch to the MPPT mode; When switching to the MPPT mode, according to the wave generation parameters of the switch tubes using open-loop wave generation in the adjusted second-stage DC topology, determining the effective wave generation parameters when the output power of the photovoltaic cell simulation source reaches the peak power; Fitting the effective wave generation parameters corresponding to the same output voltage and different peak powers respectively, and updating the fitted effective wave generation parameters to the effective wave generation parameters corresponding to the same output voltage; Based on the effective wave generation parameters corresponding to different updated output voltages respectively, performing a relationship function fitting to obtain a mathematical model mapping the output voltage and the effective wave generation parameters, so as to determine the wave generation parameters of the DC / DC in the photovoltaic power supply device in the MPPT mode based on the mathematical model.

2. The method according to claim 1, wherein After determining the effective wave generation parameters when the output power of the photovoltaic cell simulation source reaches the peak power, it further includes: Determining the output power according to the current output voltage and output current of the second-stage DC topology, or determining the input power according to the current input voltage and input current of the first-stage DC topology in the photovoltaic device; Fitting the effective wave generation parameters corresponding to the same output voltage and different peak powers respectively, including: When it is determined that the different effective wave generation parameters corresponding to the same output voltage and different peak powers do not meet the fitting requirements, segmenting the corresponding input power or output power, and the different effective wave generation parameters corresponding to the same output voltage and different peak powers in the same input / output power segment meet the fitting requirements; Fitting the different effective wave generation parameters corresponding to the same output voltage and different peak powers in the same input / output power segment into one effective wave generation parameter; Based on the effective wave generation parameters corresponding to different updated output voltages respectively, performing a relationship function fitting to obtain a mathematical model mapping the output voltage and the effective wave generation parameters, including: Performing a relationship function fitting on the effective wave generation parameters corresponding to different updated output voltages respectively in the same input / output power segment to obtain a mathematical model mapping the output voltage and the effective wave generation parameters in each input / output power segment.

3. The method according to claim 1, wherein Adjusting the output voltage of the second-stage DC topology in the photovoltaic device to be different, and adjusting the load power according to different peak powers of the photovoltaic cell simulation source to trigger a switch to the MPPT mode, including: Adjusting the load power to a peak power and keeping it unchanged, and performing a round of output voltage adjustment based on the voltage adjustment range of the output voltage; Triggering a switch to the MPPT mode every time the output voltage is adjusted; When it is determined that a round of adjustment of the load power is not completed after each round of adjustment of the output voltage, performing an adjustment of the load power once and triggering the next round of output voltage adjustment; Among them, one round of output voltage adjustment is completed by increasing or decreasing the output voltage within the voltage adjustment range according to the set voltage adjustment amplitude, and one round of load power adjustment is completed by increasing or decreasing the load power within the peak power adjustment range according to the set power adjustment amplitude.

4. The method according to any one of claims 1 to 3, characterized in that, The voltage adjustment range and the power adjustment range are determined in the following manner: Determine the maximum input voltage when the photovoltaic device is operating normally; Determine the voltage adjustment range of the output voltage according to the maximum input voltage; Determine the peak power adjustment range based on the specifications of the photovoltaic device.

5. The method according to any one of claims 1 to 3, characterized in that, According to the wave generation parameters of the switching tube using open-loop wave generation in the adjusted second-stage DC topology, determine the effective wave generation parameters when the output power of the photovoltaic cell simulation source reaches the peak power, including: Monitor the output voltage of the first-stage DC topology in the photovoltaic device when switching to the MPPT mode; If the difference between the output voltage of the first-stage DC topology and the set voltage is greater than the set threshold, adjust the wave generation parameters of the switching tube using open-loop wave generation in the second-stage DC topology; When it is determined that the difference is not greater than the set threshold, determine the current wave generation parameters as the effective wave generation parameters when the output power of the photovoltaic cell simulation source reaches the peak power.

6. The method according to any one of claims 1 to 3, characterized in that Based on the effective wave generation parameters corresponding to different updated output voltages, perform relationship function fitting, including: Based on the effective wave generation parameters corresponding to different updated output voltages, when it is determined that the difference between the effective wave generation parameters corresponding to adjacent output voltages is greater than the set threshold, divide the adjacent output voltages into different voltage segments; Based on the effective wave generation parameters corresponding to different output voltages in each voltage segment, fit the relationship function between the different output voltages and the effective wave generation parameters in this voltage segment.

7. The method according to claim 3, characterized in that, Based on the effective wave generation parameters corresponding to different updated output voltages, perform relationship function fitting, including: Based on the effective wave generation parameters corresponding to different updated output voltages, set corresponding weights for the effective wave generation parameters corresponding to different output voltages; According to the set weights, perform relationship function fitting on the effective wave generation parameters corresponding to different output voltages.

8. The method according to claim 1, wherein After obtaining the mathematical model mapping the output voltage and the effective wave generation parameters, it further includes: When it is determined that the photovoltaic device for testing enters the MPPT mode, collect the current output voltage of the photovoltaic device for testing; According to the mathematical model, determine the effective wave generation parameters corresponding to the current output voltage; According to the determined effective wave generation parameters, control the second-stage DC topology in the photovoltaic device for testing to generate waves in an open-loop wave generation manner; Detect the difference between the output voltage of the first-stage DC topology in the photovoltaic device for testing and the set voltage, and detect the peak power tracking accuracy of open-loop wave generation using the mathematical model according to the difference.

9. The method according to claim 1, wherein The wave generation parameters of the adjusted open-loop wave generation include: Wave generation frequency, wave generation variable duty cycle, or wave generation phase misalignment angle.

10. A DC / DC wave - generating method of a photovoltaic power supply device in the MPPT mode, characterized in that, The method includes: When it is determined that the photovoltaic power supply device enters the MPPT mode, collect the current output voltage of the photovoltaic power supply device; According to the mathematical model mapping the output voltage and the effective wave generation parameters constructed by any one of the methods in claims 1 to 9, determine the effective wave generation parameters corresponding to the current output voltage; According to the effective wave generation parameters, the second - stage DC topology generates waves in an open - loop wave generation mode.

11. The method according to claim 10, wherein It further includes: Determining the current output power according to the current output voltage and output current of the second - stage DC topology, or determining the current input power according to the current input voltage and input current of the first - stage DC topology; According to the mathematical model mapping the relationship between the output voltage and the effective wave generation parameters, determining the effective wave generation parameters corresponding to the current output voltage, including: Determining the current input power segment where the current input power is located, or the current output power segment where the current output power is located, and determining the effective wave generation parameters corresponding to the current input / output power segment according to the mathematical model of the relationship between the mapped output voltage and the effective wave generation parameters under each input / output power segment.

12. A DC / DC wave generation device of a photovoltaic power supply device in the MPPT mode, characterized in that, It includes: A simulation device construction module for constructing a photovoltaic cell simulation source; A device parameter adjustment module for adjusting the output voltage of the second - stage DC topology in the photovoltaic device based on the photovoltaic cell simulation source, and adjusting the load power according to different peak powers of the photovoltaic cell simulation source to trigger the switch to the MPPT mode; A wave generation parameter determination module for, when switching to the MPPT mode, determining the effective wave generation parameters when the output power of the photovoltaic cell simulation source reaches the peak power according to the wave generation parameters of the switching tube adopting open - loop wave generation in the adjusted second - stage DC topology; A wave generation parameter fitting module for fitting the effective wave generation parameters corresponding to the same output voltage and different peak powers respectively, and updating the fitted effective wave generation parameters as the effective wave generation parameters corresponding to the same output voltage; A mathematical model construction module for performing relationship function fitting based on the updated effective wave generation parameters corresponding to different output voltages respectively, to obtain a mathematical model mapping the relationship between the output voltage and the effective wave generation parameters, so as to determine the wave generation parameters of the DC / DC in the photovoltaic power supply device in the MPPT mode based on the mathematical model.

13. A DC / DC wave generating device of a photovoltaic power supply device in the MPPT mode, characterized in that, It includes at least one processor; and a memory communicatively connected to the at least one processor; wherein, the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method according to any one of claims 1 - 11.

14. A photovoltaic power supply device, characterized in that, It includes: Photovoltaic cells; A first - stage DC topology connected to the photovoltaic cells, including an input voltage loop for controlling the input voltage of the first - stage DC topology and a bus voltage loop for controlling the output voltage of the first - stage DC topology; A second - stage DC topology connected to the first - stage DC topology, including switching tubes for controlling the output voltage, output current, and power; An open - loop wave generation control module connected to the switching tubes of the second - stage DC topology, for collecting the output voltage of the second - stage DC topology, obtaining wave generation parameters by using the mathematical model constructed by any one of the methods according to claims 1 - 11, and controlling the switching tubes in the second - stage DC topology by using the wave generation parameters.

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