Power supply control method, device, controller, grid-connected power generation system and storage medium

Abstract

The present invention provides a power supply control method, device, controller, grid-connected power generation system and storage medium. Applied to a grid-connected power generation system for supplying power to the grid, the method includes: monitoring the three-phase output current value and three-phase output voltage value of an inverter in the grid-connected power generation system; if it is monitored that the three-phase output current value and three-phase output voltage value meet the first condition or the second condition, controlling the inverter to be in a pulse locking state so that the reverse peak voltage of the switching tube in the inverter does not exceed a given reverse peak voltage. The present invention can reduce the reverse peak voltage of the switching tube.

Description

Technical Field

[0001] The present invention relates to the field of power supply control technology, and in particular to a power supply control method, device, controller, grid-connected power generation system and storage medium. Background Art

[0002] Photovoltaic (PV) is a clean grid-connected power generation technology that is widely used in all walks of life. Usually, a PV power generation system is connected to the grid to supply power. However, the inventors have found that when the grid voltage drops and recovers from the drop state, the bus voltage in the PV power generation system may rise, causing the reverse peak voltage of some switch tubes of the inverter in the PV power generation system to exceed the standard, increasing the risk of device failure and easily leading to safety accidents. Summary of the invention

[0003] The embodiments of the present invention provide a power supply control method, device, controller, grid-connected power generation system and storage medium to solve the problem that when a voltage drop occurs in the power grid and recovers from the drop state, the bus voltage in the grid-connected power generation system may be increased, causing the reverse peak voltage of some switching tubes of the inverter in the grid-connected power generation system to exceed the standard, increasing the risk of device failure and easily causing safety accidents.

[0004] In a first aspect, the present invention provides a power supply control method, which is applied to a grid-connected power generation system for supplying power to a power grid, the method comprising:

[0005] When the power grid recovers from a drop to a normal state, the three-phase output current value and the three-phase output voltage value of the inverter in the grid-connected power generation system are obtained;

[0006] If the three-phase output current value and the three-phase output voltage value meet the first condition or the second condition, the inverter is controlled to be in a pulse locking state so that the reverse peak voltage of the switch tube in the inverter does not exceed the given reverse peak voltage.

[0007] In a possible implementation manner, after controlling the inverter to be in a pulse blocking state, the method further includes:

[0008] After the first time period, the pulse blocking of the inverter is released.

[0009] In one possible implementation, the first condition includes: within a first number of consecutive switching cycles, there are two phases in the inverter whose product of voltage and current values ​​is less than zero, and for the phase whose product of voltage and current values ​​is less than zero, the ratio of the output current value of the phase to the corresponding standard output current value is greater than a first preset ratio.

[0010] In a possible implementation, the second condition includes: within a second number of consecutive switching cycles, the product of the voltage value and the current value of one phase in the inverter is less than zero, and for the phase where the product of the voltage value and the current value is less than zero, the ratio of the output current value of this phase to the corresponding standard output current value of this phase is greater than a second preset ratio; the first preset ratio is less than the second preset ratio.

[0011] In a possible implementation, before monitoring the three-phase output current values and three-phase output voltage values of the inverter in the grid-connected power generation system, the method further includes:

[0012] Obtaining the output voltage value of the power supply module in the grid-connected power generation system;

[0013] Correspondingly, if it is monitored that the three-phase output current values and three-phase output voltage values satisfy the first condition or the second condition, controlling the inverter to be in a pulse locking state includes:

[0014] If the output voltage value of the power supply module is greater than a first preset voltage value, and the three-phase output current values and three-phase output voltage values satisfy the first condition or the second condition, then controlling the inverter to be in a pulse locking state.

[0015] In a second aspect, an embodiment of the present invention provides a control device, which is applied to a grid-connected power generation system for supplying power to the grid. The control device includes:

[0016] An acquisition module, configured to monitor the three-phase output current values and three-phase output voltage values of the inverter in the grid-connected power generation system;

[0017] A control module, configured to control the inverter to be in a pulse locking state if it is monitored that the three-phase output current values and three-phase output voltage values satisfy the first condition or the second condition, so that the reverse peak voltage of the switching tube in the inverter does not exceed a given reverse peak voltage.

[0018] In a possible implementation, the power supply control device further includes:

[0019] A first locking module, configured to release the pulse locking of the inverter after a first time period after controlling the inverter to be in a pulse locking state.

[0020] In a third aspect, the present invention provides a controller, including a memory and a processor. A computer program that can run on the processor is stored in the memory. When the processor executes the computer program, the steps of the power supply control method in the first aspect or any possible implementation manner of the first aspect are implemented.

[0021] In a fourth aspect, the present invention provides a grid-connected power generation system, including the controller in the third aspect above, and a PV module, a DC / DC converter, and an inverter connected in sequence; the PV module, the DC / DC converter, and the inverter are all controlled by the controller.

[0022] In a fifth aspect, the present invention provides a computer-readable storage medium storing a computer program, which when executed by a processor implements the steps of the power supply control method in the first aspect above or any possible implementation manner of the first aspect.

[0023] The embodiments of the present invention provide a power supply control method, device, controller, grid-connected power generation system and storage medium. By real-time monitoring whether the three-phase output current value and the three-phase output voltage value of the inverter in the grid-connected power generation system meet the first condition or the second condition, when the first condition or the second condition is met, the inverter pulse is accurately locked to reduce the reverse peak voltage of the switching tube; when the first condition or the second condition is not met, the inverter pulse is not controlled to be locked, so that the grid-connected power generation system can work normally. By monitoring the three-phase current value and the three-phase voltage value and combining the first condition and the second condition, not only the reverse peak voltage of the switching tube is reduced, the service life and working reliability of the switching tube are improved, and the risk of device failure is reduced, but also the normal operation of the inverter is not affected, and the working reliability of the grid-connected power generation system is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 is a schematic diagram of an application scenario provided by an embodiment of the present invention;

[0026] Figure 2 is a schematic diagram of a control loop provided by an embodiment of the present invention;

[0027] Figure 3 is a flowchart of the implementation of the power supply control method provided by an embodiment of the present invention;

[0028] Figure 4 is a schematic diagram of the structure of the control device provided by an embodiment of the present invention;

[0029] Figure 5 is a schematic diagram of the controller provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] In the following description, specific details such as specific system architectures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present invention. However, those skilled in the art should clearly understand that the present invention can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present invention.

[0031] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will be described through specific embodiments in conjunction with the accompanying drawings.

[0032] Refer to Figure 1 , which shows a schematic diagram of an application scenario provided by an embodiment of the present invention. As Figure 1 shown, the grid-connected power generation system may include a power supply module, a DC / DC converter, and an inverter connected in sequence. The power supply module is used to provide raw electrical energy and supply power to the grid through the DC / DC converter and the inverter. For example, the power supply module may be a PV module for converting light energy into electrical energy.

[0033] Figure 2 is a schematic diagram of a control loop provided by an embodiment of the present invention. This control loop is a feedback control loop for controlling Figure 1 the output of the inverter in. Among them, I_ref is the given current value, I_fdb is the actual current value, and U_grid is the current grid voltage. In addition, in order to ensure the stability of system control, it is generally necessary to set an LPF low-pass filter to filter the current grid voltage, that is, the LPF low-pass filter is necessary.

[0034] The inventor found that when using the control loop as Figure 2 shown to control the inverter in the grid-connected power generation system, during the process of the grid recovering from the droop state to the normal state, due to the existence of the LPF in this control loop, filtering takes time, which will cause the current grid voltage value to be higher than the calculated given voltage value, and then current backflow occurs in the inverter. Even more seriously, it may cause the reverse peak voltage of some switching tubes in the inverter to exceed the standard, which may damage the devices and easily cause safety accidents. Among them, the droop of the grid refers to the rapid decrease in the effective value of the grid voltage and maintaining it for a certain period of time. For example, it drops to 90%-10% of the rated value in the normal state, or drops to 0V and maintains for 10ms.

[0035] To solve the above problems, an embodiment of the present invention provides a power supply control method applied to a grid-connected power generation system that supplies power to the grid in parallel. Refer to Figure 3 , which shows a flowchart of the implementation of the power supply control method provided by an embodiment of the present invention. As Figure 3 shown, a power supply control method may include:

[0036] S101, Monitor the three-phase output current values and three-phase output voltage values of the inverter in the grid-connected power generation system.

[0037] Optionally, the grid-connected power generation system can be a PV power generation system. During the operation of the grid-connected power generation system, current reverse injection may occur. When current reverse injection occurs, the reverse peak voltage of the switching tube will increase and may exceed the standard. By monitoring the three-phase output current values and three-phase output voltage values of the inverter in the grid-connected power generation system in real time, it is possible to determine whether there is a phase with current reverse injection in the grid-connected power generation system, and then identify the phase with excessive reverse peak voltage.

[0038] Specifically, obtaining the three-phase output current values of the inverter in the grid-connected power generation system includes: obtaining the first-phase output current value of the inverter, obtaining the second-phase output current value of the inverter, and obtaining the third-phase output current value of the inverter.

[0039] Obtaining the three-phase output voltage values of the inverter in the grid-connected power generation system includes: obtaining the first-phase output voltage value of the inverter, obtaining the second-phase output voltage value of the inverter, and obtaining the third-phase output voltage value of the inverter.

[0040] S102, If the three-phase output current values and three-phase output voltage values meet the first condition or the second condition, then control the inverter to be in a pulse blocking state, so that the reverse peak voltage of the switching tube in the inverter does not exceed the given reverse peak voltage.

[0041] Optionally, the first condition or the second condition is a condition for judging whether the reverse peak of the inverter exceeds the standard. The given reverse peak voltage is the maximum reverse peak voltage that the switching tube can withstand by itself.

[0042] For each phase, the product of the output current value and output voltage value of this phase can be used to judge whether current reverse injection occurs in this phase, and then judge whether current reverse injection occurs in the inverter. The ratio of the output current value of this phase to the corresponding standard output current value of this phase can be used to judge the degree of current reverse injection in this phase, and then judge the degree of current reverse injection in the inverter. Combining the number of phases with current reverse injection in the inverter and the degree of current reverse injection can judge the reverse peak degree of the switching tube in the inverter.

[0043] Optionally, the first condition is a condition for when there are two phases with current reverse injection in the inverter and the degree of current reverse injection in these two phases is relatively large, resulting in the possible exceeding of the reverse peak voltage of the switching tube in the inverter. The second condition is a condition for when there is one phase with current reverse injection in the inverter and the degree of current reverse injection in this phase is relatively large, resulting in the possible exceeding of the reverse peak voltage of the switching tube in the inverter.

[0044] Optionally, controlling the inverter to be in a pulse blocking state means controlling all the switching tubes in the inverter to turn off, that is, controlling the duty cycle of all the switching tubes to be zero.

[0045] Optionally, after controlling the inverter to be in the pulse locking state, the pulse locking of the inverter can be released after a first duration, so that the inverter can work normally. The first duration is the shortest duration for eliminating the overshoot of the switch tube voltage peak, and can be determined according to the actual situation. For example, the first duration can be 3 ms.

[0046] In the embodiments of the present invention, by monitoring in real time whether the three-phase output current values and three-phase output voltage values of the inverter satisfy the first condition or the second condition, it is determined whether current reverse injection occurs in the inverter, and further whether the switch tube voltage peak exceeds the standard. When the switch tube voltage peak of the inverter exceeds the standard, the switch tube pulse locking of the inverter is controlled to reduce the reverse peak voltage of the switch tube; when the switch tube voltage peak of the inverter does not exceed the standard, the inverter is controlled not to be pulse locked, so that the grid-connected power generation system works normally. On the basis of achieving the purpose of protecting the device, the normal operation of the inverter is not affected, and the working reliability of the inverter and the safety of the grid-connected power generation system can be improved.

[0047] In some embodiments of the present invention, the first condition may include: within a first number of consecutive switching cycles, the product of the voltage value and the current value of two phases in the inverter is less than zero, and for the phase where the product of the voltage value and the current value is less than zero, the ratio of the output current value of this phase to the corresponding standard output current value of this phase is greater than a first preset ratio.

[0048] Optionally, by judging whether the product of the voltage value and the current value is less than zero within a first number of consecutive switching cycles, it can be judged whether current reverse injection occurs. For example, the first number can be three. The first number is specifically selected according to the actual situation.

[0049] Specifically, within a first number of consecutive switching cycles, the product of the voltage value and the current value of two phases in the inverter being less than zero may include:

[0050] The product of the current value and the voltage value of the first phase is less than zero, and the product of the current value and the voltage value of the second phase is less than zero; or, the product of the current value and the voltage value of the first phase is less than zero, and the product of the current value and the voltage value of the third phase is less than zero; or, the product of the current value and the voltage value of the second phase is less than zero, and the product of the current value and the voltage value of the third phase is less than zero.

[0051] Wherein, when the product of the current value and the voltage value of the first phase is less than zero, and the product of the current value and the voltage value of the second phase is less than zero: the ratio of the output current value of the first phase to the corresponding standard output current value of the first phase is greater than the first preset ratio, and the ratio of the output current value of the second phase to the corresponding standard output current value of the second phase is greater than the first preset ratio.

[0052] When the products of the current values and voltage values of the first phase are all less than zero, and the products of the current values and voltage values of the third phase are all less than zero: the ratios of the output current values of the first phase to the corresponding standard output current values of the first phase are all greater than a first preset ratio, and the ratios of the output current values of the third phase to the corresponding standard output current values of the third phase are all greater than the first preset ratio.

[0053] When the products of the current values and voltage values of the second phase are all less than zero, and the products of the current values and voltage values of the third phase are all less than zero: the ratios of the output current values of the second phase to the corresponding standard output current values of the third phase are all greater than a first preset ratio, and the ratios of the output current values of the third phase to the corresponding standard output current values of the third phase are all greater than the first preset ratio.

[0054] The first preset ratio can be 15% of the standard output current of each phase, and can be specifically set according to the actual situation.

[0055] In some embodiments of the present invention, the second condition may include: within a second number of consecutive switching cycles, there is a phase in the inverter where the product of the voltage value and the current value is less than zero, and for the phase where the product of the voltage value and the current value is less than zero, the ratio of the output current value of this phase to the corresponding standard output current value of this phase is greater than a second preset ratio.

[0056] Optionally, by judging whether the product of the voltage value and the current value is less than zero within a second number of consecutive switching cycles, it is also possible to judge whether current reverse injection occurs. The first number and the second number can be equal or not equal.

[0057] When the first number is equal to the second number, the monitoring efficiency can be improved by reducing the monitoring period. When the first number and the second number are not equal, the monitoring means can be set specifically to improve the monitoring accuracy. It can be specifically set according to the requirements of the monitoring time and the monitoring accuracy. For example, both the first number and the second number can be three, or the first number is three and the second number is six.

[0058] Specifically, within a second number of consecutive switching cycles, the situation that there is a phase in the inverter where the product of the voltage value and the current value is less than zero may include:

[0059] The products of the voltage values and current values of the first phase are all less than zero; or, the products of the voltage values and current values of the second phase are all less than zero; or, the products of the voltage values and current values of the third phase are all less than zero.

[0060] Among them, when the products of the voltage values and current values of the first phase are all less than zero: the ratios of the output current values of the first phase to the corresponding standard output current values of the first phase are all greater than the second preset ratio.

[0061] When the product of the voltage value and the current value of the second phase is less than zero: the ratio of the output current value of the second phase to the standard output current value corresponding to the second phase is greater than the second preset ratio.

[0062] When the product of the voltage value and the current value of the third phase is less than zero: the ratio of the output current value of the third phase to the standard output current value corresponding to the third phase is greater than the second preset ratio.

[0063] The first preset ratio can be less than the second preset ratio. The second preset ratio can be 30% of the standard output current of each phase.

[0064] Exemplarily, if it is monitored that the three-phase output current values and the three-phase output voltage values satisfy the first condition or the second condition, the inverter is controlled to be in a pulse locking state, reducing the reverse peak voltage of the switching tubes in the inverter, so that the reverse peak voltage of the switching tubes in the inverter does not exceed the given reverse peak voltage;

[0065] Wherein, the first condition includes: within three consecutive switching cycles, when the product of the current value and the voltage value of the first phase is less than zero, and the product of the current value and the voltage value of the second phase is less than zero: the ratio of the output current value of the first phase to the standard output current value corresponding to the first phase is greater than the first preset ratio, and the ratio of the output current value of the second phase to the standard output current value corresponding to the second phase is greater than the first preset ratio.

[0066] The second condition includes: within three consecutive switching cycles, the product of the voltage value and the current value of the first phase is less than zero, and the ratio of the output current value of the first phase to the standard output current value corresponding to the first phase is greater than the second preset ratio.

[0067] In some embodiments of the present invention, it is possible to judge whether current reverse injection occurs in the inverter by the number of phases in which the product of the output voltage value and the output current value is less than zero.

[0068] Exemplarily, for the first phase of the inverter, if the product of the output current value of the first phase and the output voltage value of the first phase is less than zero, it is determined that current reverse injection occurs in the first phase of the inverter. For the second phase of the inverter, if the product of the output current value of the second phase and the output voltage value of the second phase is less than zero, it is determined that current reverse injection occurs in the second phase of the inverter. For the third phase of the inverter, if the product of the output current value of the third phase and the output voltage value of the third phase is less than zero, it is determined that current reverse injection occurs in the third phase of the inverter. If current reverse injection occurs in at least one phase of the inverter, it is determined that current reverse injection occurs in the inverter.

[0069] The specific conditions for judging current reverse injection in the inverter can be selected according to the working reliability requirements of the inverter. For example, if the given reverse peak voltage of the switching tube in the inverter is relatively high, it can be selected that when current reverse injection occurs in all three phases of the inverter, it is determined that current reverse injection occurs in the inverter. If the given reverse peak voltage in the inverter is relatively low, it can be selected that when current reverse injection occurs in one phase of the inverter, it is determined that current reverse injection occurs in the inverter. By combining the given reverse peak voltage of the switching tube in the inverter to select the first condition, the number of pulse lockouts can be reduced as much as possible, and the maximum working reliability of the inverter can be ensured without exceeding the reverse peak voltage of the switching tube.

[0070] In some embodiments of the present invention, before obtaining the three-phase output current values and three-phase output voltage values of the inverter in the grid-connected power generation system, the power supply control method further includes:

[0071] Obtaining the output voltage value of the power supply module in the grid-connected power generation system;

[0072] Correspondingly, the "if it is monitored that the three-phase output current values and three-phase output voltage values meet the first condition or the second condition, then control the inverter to be in a pulse lockout state" in the above S102 may include:

[0073] If the output voltage value of the power supply module is greater than the first preset voltage value, and the three-phase output current values and three-phase output voltage values meet the first condition or the second condition, then control the inverter to be in a pulse lockout state.

[0074] Optionally, when the output voltage value of the power supply module is greater than the first preset voltage value and current reverse injection occurs in the inverter, the reverse peak voltage of the switching tube in the inverter will become higher. By adding the voltage determination of the PV module, the reverse peak voltage of the switching tube can be controlled more accurately and reliably to exceed the standard.

[0075] Optionally, when the output voltage value of the power supply module is the first preset voltage value, if current reverse injection occurs, the reverse peak voltage of the switching tube in the inverter is the given reverse peak voltage. The setting of the first preset voltage value can avoid misjudgment, and while ensuring that the reverse peak voltage of the switching tube does not exceed the standard, the pulse lockout time and number of times of the inverter are reduced as much as possible, and unnecessary protection is reduced. For example, the first preset voltage value can be 950V.

[0076] In some embodiments of the present invention, after monitoring the three-phase output current values and three-phase output voltage values of the inverter in the grid-connected power generation system, the power supply control method further includes:

[0077] If it is detected that the three-phase output current values and three-phase output voltage values meet the first condition, the second condition or the third condition, then control the inverter to be in a pulse lockout state so that the reverse peak voltage of the switching tube in the inverter does not exceed the given reverse peak voltage.

[0078] The third condition may include:

[0079] In a third number of consecutive switching cycles, the products of the three-phase voltage values ​​and the three-phase current values ​​of the inverter are all less than zero, and for each phase, the ratio of the output current value of the phase to the corresponding standard output current value is greater than a third preset ratio. The third preset ratio is less than the first preset ratio.

[0080] Exemplarily, the control process of the power supply control method of the embodiment of the present invention is as follows:

[0081] Obtain the output voltage value of the power supply module, and obtain the three-phase output voltage value and three-phase output current value of the inverter.

[0082] If the output voltage value of the power supply module is greater than 950V, and two of the three phases of the inverter have "the product of the output current value and the output voltage value is less than zero" in three consecutive switching cycles, and "the ratio of the output current value of the phase whose product is less than zero to the standard output current value of the phase is greater than 0.15", then the control inverter is in a pulse locking state for 3ms, and then the pulse locking state is released.

[0083] If the output voltage value of the power supply module is greater than 950V, and one of the three phases of the detection inverter has "the product of the output current value and the output voltage value is less than zero" in three consecutive switching cycles, and "the ratio of the output current value of this phase to the standard output current value of this phase is greater than 0.3", then the control inverter is in a pulse locking state for 3ms, and then the pulse locking state is released.

[0084] Through the above control, the reverse peak voltage of the switch tube in the inverter can be optimized by 50V. For example, if the given reverse peak voltage of the switch tube is 630V, if pulse blocking is not performed, the reverse peak voltage of the switch tube may reach 650V. After pulse blocking, the reverse peak voltage of the switch tube can be optimized to 600V, which can greatly improve the service life of the switch tube.

[0085] The embodiment of the present invention monitors the output voltage of the power supply module and the three-phase output voltage and three-phase output current of the inverter in real time, and controls the inverter pulse lockout according to the three-phase output current and three-phase output voltage, thereby reducing the reverse peak voltage of the switch tube. At the same time, it can reduce the lockout time and number of the inverter, reduce misjudgment, extend the service life of the device, and improve the working reliability of the grid-connected power generation system.

[0086] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0087] The following is an embodiment of the device of the present invention. For details not described in detail, reference may be made to the corresponding method embodiment above.

[0088] Figure 4 The structural schematic diagram of the control device provided by the embodiment of the present invention is shown. For the convenience of description, only the parts related to the embodiment of the present invention are shown and are described in detail as follows:

[0089] As Figure 4 shown, the control device 20 is applied to a grid-connected power generation system that supplies power to the grid and may include:

[0090] An acquisition module, configured to monitor the three-phase output current value and the three-phase output voltage value of the inverter in the grid-connected power generation system;

[0091] A control module, configured to control the inverter to be in a pulse locking state if it is monitored that the three-phase output current value and the three-phase output voltage value meet the first condition or the second condition, so that the reverse peak voltage of the switching tube in the inverter does not exceed the given reverse peak voltage.

[0092] In some embodiments of the present invention, the control device 20 may further include: a first locking module, configured to release the pulse locking of the inverter after a first duration after controlling the inverter to be in the pulse locking state.

[0093] In some embodiments of the present invention, the first condition includes:

[0094] In the first number of consecutive switching cycles, the product of the voltage value and the current value of two phases in the inverter is less than zero, and for the phase where the product of the voltage value and the current value is less than zero, the ratio of the output current value of this phase to the corresponding standard output current value of this phase is greater than a first preset ratio.

[0095] In some embodiments of the present invention, the second condition includes:

[0096] In the second number of consecutive switching cycles, the product of the voltage value and the current value of one phase in the inverter is less than zero, and for the phase where the product of the voltage value and the current value is less than zero, the ratio of the output current value of this phase to the corresponding standard output current value of this phase is greater than a second preset ratio; the first preset ratio is less than the second preset ratio.

[0097] In some embodiments of the present invention, the control device 20 may further include:

[0098] A second locking module, configured to obtain the output voltage value of the power supply module in the grid-connected power generation system before monitoring the three-phase output current value and the three-phase output voltage value of the inverter in the grid-connected power generation system;

[0099] Correspondingly, the control module is further configured to control the inverter to be in a pulse locking state if the output voltage value of the power supply module is greater than the first preset voltage value and the three-phase output current value and the three-phase output voltage value satisfy the first condition or the second condition.

[0100] Figure 5 is a schematic diagram of the controller provided by an embodiment of the present invention. As Figure 5 shown, the controller 30 of this embodiment includes: a processor 300 and a memory 301, and a computer program 302 that can run on the processor 300 is stored in the memory 301. When the processor 300 executes the computer program 302, the steps in the above-mentioned embodiments of each power supply control method are implemented, for example Figure 3 the S101 to S102 shown. Alternatively, when the processor 300 executes the computer program 302, the functions of each module / unit in the above-mentioned device embodiments are implemented, for example Figure 4 the functions of the modules / units 201 to 202 shown.

[0101] Exemplarily, the computer program 302 can be divided into one or more modules / units. One or more modules / units are stored in the memory 301 and executed by the processor 300 to complete the present invention. One or more modules / units can be a series of computer program instruction segments capable of performing specific functions, and this instruction segment is used to describe the execution process of the computer program 302 in the controller 30. For example, the computer program 302 can be divided into Figure 4 the modules / units 201 to 202 shown.

[0102] The controller 30 can be a DSP chip or a single-chip microcomputer chip, and can also be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The controller 30 may include, but is not limited to, a processor 300 and a memory 301. Those skilled in the art can understand that Figure 5 is only an example of the controller 30, and does not constitute a limitation on the controller 30. It may include more or fewer components than shown in the figure, or combine certain components, or different components. For example, the controller may further include input / output devices, network access devices, buses, etc.

[0103] The so-called processor 300 may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor, or the processor may also be any conventional processor, etc.

[0104] The memory 301 may be an internal storage unit of the controller 30, such as the hard disk or memory of the controller 30. The memory 301 may also be an external storage device of the controller 30, such as a plug-in hard disk equipped on the controller 30, a Smart Media Card (SMC), a Secure Digital (SD) card, a Flash Card, etc. Further, the memory 301 may also include both the internal storage unit of the controller 30 and the external storage device. The memory 301 is used to store computer programs and other programs and data required by the controller. The memory 301 may also be used to temporarily store data that has been output or is to be output.

[0105] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above division of each functional unit and module is used as an example. In actual applications, the above functions can be allocated to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit. In addition, the specific names of each functional unit and module are only for the convenience of mutual distinction and do not limit the protection scope of this application. The specific working processes of the units and modules in the above system can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0106] The embodiment of the present invention also provides a grid-connected power generation system, including the above-mentioned controller 30 and a power supply module, a DC / DC converter, and an inverter connected in sequence; wherein, the power supply module, the DC / DC converter, and the inverter are all controlled by the controller.

[0107] Optionally, the power supply module can be a PV module.

[0108] In the above embodiments, the descriptions of the various embodiments have their own emphases. For the parts not detailed or recorded in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0109] Those of ordinary skill in the art can realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0110] In the embodiments provided by the present invention, it should be understood that the disclosed device / controller and method can be implemented in other ways. For example, the device / controller embodiments described above are merely illustrative. For example, the division of modules or units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the device or unit can be in electrical, mechanical or other forms.

[0111] The units described as separate components may or may not be physically separated. The components shown as units may or may not be physical units, that is, they can be located in one place, or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0112] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated units can be implemented in the form of hardware or in the form of software functional units.

[0113] When the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, to implement all or part of the processes in the above-described embodiment methods of the present invention, it can also be completed by a computer program instructing relevant hardware. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above-described various power supply control method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file, or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disc, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0114] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A power supply control method, characterized in that, Applicable to a grid-connected power generation system for supplying power to a power grid, the power supply control method comprises: Monitoring the three-phase output current value and the three-phase output voltage value of the inverter in the grid-connected power generation system; If it is monitored that the three-phase output current value and the three-phase output voltage value meet the first condition or the second condition, the inverter is controlled to be in a pulse locking state so that the reverse peak voltage of the switch tube in the inverter does not exceed a given reverse peak voltage; The first condition includes: In a first number of continuous switching cycles, the inverter has two phases whose voltage and current products are less than zero, and for a phase whose voltage and current products are less than zero, a ratio of an output current value of the phase to a corresponding standard output current value is greater than a first preset ratio; The second condition includes: Within a second number of consecutive switching cycles, there is a phase in the inverter whose product of voltage and current is less than zero, and for the phase whose product of voltage and current is less than zero, the ratio of the output current value of the phase to the corresponding standard output current value is greater than a second preset ratio; the first preset ratio is less than the second preset ratio.

2. The power supply control method according to claim 1, characterized in that, After controlling the inverter to be in a pulse blocking state, the method further includes: After a first period of time, the pulse blocking of the inverter is released.

3. The power supply control method according to claim 1 or 2, characterized in that, Before monitoring the three-phase output current value and the three-phase output voltage value of the inverter in the grid-connected power generation system, the method further includes: Obtaining an output voltage value of a power supply module in the grid-connected power generation system; Correspondingly, if it is monitored that the three-phase output current value and the three-phase output voltage value meet the first condition or the second condition, the inverter is controlled to be in a pulse blocking state, including: If the output voltage value of the power supply module is greater than the first preset voltage value, and the three-phase output current value and the three-phase output voltage value meet the first condition or the second condition, the inverter is controlled to be in a pulse locking state.

4. A power supply control device, characterized in that, Applicable to a grid-connected power generation system for supplying power to a power grid, the power supply control device comprises: An acquisition module, used for monitoring the three-phase output current value and the three-phase output voltage value of the inverter in the grid-connected power generation system; A control module, configured to control the inverter to be in a pulse blocking state if it is monitored that the three-phase output current value and the three-phase output voltage value meet the first condition or the second condition, so that the reverse peak voltage of the switch tube in the inverter does not exceed a given reverse peak voltage; The first condition includes: In a first number of continuous switching cycles, the inverter has two phases whose voltage and current products are less than zero, and for a phase whose voltage and current products are less than zero, a ratio of an output current value of the phase to a corresponding standard output current value is greater than a first preset ratio; The second condition includes: Within a second number of consecutive switching cycles, there is a phase in the inverter whose product of voltage and current is less than zero, and for the phase whose product of voltage and current is less than zero, the ratio of the output current value of the phase to the corresponding standard output current value is greater than a second preset ratio; the first preset ratio is less than the second preset ratio.

5. The power supply control device according to claim 4, characterized in that, The power supply control device also includes: The first locking module is configured to release the pulse locking of the inverter after a first duration after controlling the inverter to be in the pulse locking state.

6. A controller, comprising a memory and a processor, wherein a computer program that can run on the processor is stored in the memory, characterized in that, When the processor executes the computer program, the steps of the power supply control method according to any one of claims 1 to 3 above are implemented.

7. A grid-connected power generation system, characterized in that, It includes a controller according to claim 6, and a PV module, a DC / DC converter, and an inverter connected in sequence; the PV module, the DC / DC converter, and the inverter are all controlled by the controller.

8. A computer-readable storage medium, the computer-readable storage medium stores a computer program, characterized in that, When the computer program is executed by a processor, the steps of the power supply control method according to any one of claims 1 to 3 above are implemented.

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