Control method of a converter and energy storage system

Abstract

The application provides a control method of a converter and an energy storage system. The method is applied to a bidirectional converter; a first port of the bidirectional converter is provided with a first capacitor, and a second port of the bidirectional converter is provided with a second capacitor; the control method comprises the following steps: obtaining a voltage effective value of the first port and a voltage effective value of the second port; if the voltage effective value of the first port is greater than a first preset voltage or the voltage effective value of the second port is greater than a second preset voltage, the bidirectional converter is controlled to alternately work in a first conversion state and a second conversion state until the voltage effective value of the first port is not greater than the first preset voltage and the voltage effective value of the second port is not greater than the second preset voltage. The application only controls the switching tube of the bidirectional converter to work alternately, continuously consumes the stored energy until the port voltage meets the requirement, and the control method is simple, and a separate discharge circuit is not needed, so that the circuit complexity is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power supply, in particular to a control method of a converter and an energy storage system. BACKGROUND

[0002] DC-DC converter is a kind of power electronic device that converts DC power into the required voltage of the load. It controls the on-off of the switch tube quickly, combines the energy storage and release of the energy storage element, cuts the constant DC voltage into a series of pulse voltage, and then gets the appropriate DC voltage through filtering. One end of the DC-DC converter is connected with the battery, and the other end is connected with the DC bus. When the system is turned off, the DC-DC converter is disconnected with the battery and the DC bus. When the system is restarted, the DC-DC converter is reconnected with the battery and the DC bus.

[0003] In the prior art, due to the existence of the energy storage element, the energy of the energy storage element cannot be released when the system is turned off, which will cause the switch between the DC-DC converter and the battery or the DC bus to be unable to close due to the excessive voltage difference. Therefore, a bleeder circuit needs to be arranged in the DC-DC converter to release the energy of the energy storage element, which increases the complexity of the circuit. SUMMARY

[0004] The embodiments of the present application provide a control method of a converter and an energy storage system to solve the problem of the prior art that a separate bleeder circuit needs to be arranged in the bidirectional converter due to the existence of the energy storage element, which increases the complexity of the circuit.

[0005] In a first aspect, the embodiments of the present application provide a control method of a converter, which is applied to a bidirectional converter; wherein a first port of the bidirectional converter is provided with a first capacitor, and a second port of the bidirectional converter is provided with a second capacitor; the control method comprises the following steps:

[0006] obtaining the effective value of the voltage of the first port and the effective value of the voltage of the second port;

[0007] if the effective value of the voltage of the first port is greater than a first preset voltage, or the effective value of the voltage of the second port is greater than a second preset voltage, then the bidirectional converter is controlled to alternately work in a first conversion state and a second conversion state until the effective value of the voltage of the first port is not greater than the first preset voltage, and the effective value of the voltage of the second port is not greater than the second preset voltage.

[0008] In a second aspect, the embodiments of the present application provide an energy storage system, which comprises a DC power supply and a bidirectional converter; wherein a first port of the bidirectional converter is provided with a first capacitor, and a second port of the bidirectional converter is provided with a second capacitor;

[0009] the first port of the bidirectional converter is connected with an external device, and the second port of the bidirectional converter is connected with the DC power supply;

[0010] When the bidirectional converter is in the bleeder state machine, the bidirectional converter applies the steps of the control method of the converter provided in the first aspect of the embodiment of the present application;

[0011] When the bidirectional converter exits the bleeder state machine, the bidirectional converter does not apply the steps of the control method of the converter provided in the first aspect of the embodiment of the present application;

[0012] The embodiment of the present application provides a control method of a converter and an energy storage system. The method is applied to a bidirectional converter; wherein a first port of the bidirectional converter is provided with a first capacitor, and a second port of the bidirectional converter is provided with a second capacitor; the control method comprises the following steps: obtaining a voltage effective value of the first port and a voltage effective value of the second port; if the voltage effective value of the first port is greater than a first preset voltage, or the voltage effective value of the second port is greater than a second preset voltage, then controlling the bidirectional converter to alternately work in a first conversion state and a second conversion state until the voltage effective value of the first port is not greater than the first preset voltage and the voltage effective value of the second port is not greater than the second preset voltage. In the embodiment of the present application, only by controlling the switching tube of the bidirectional converter to work alternately (alternately working in the first conversion state and the second conversion state), the energy stored in the energy storage element is continuously consumed until the port voltage meets the requirement, the control method is simple, a separate bleeder circuit does not need to be set, and the circuit complexity is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative labor.

[0014] Figure 1 is a structure schematic diagram of a bidirectional converter provided by the embodiment of the present application;

[0015] Figure 2 is an implementation flowchart of a control method of a converter provided by the embodiment of the present application;

[0016] Figure 3 is a structure schematic diagram of a control device of a converter provided by the embodiment of the present application;

[0017] Figure 4 is a schematic diagram of a control terminal provided by the embodiment of the present application;

[0018] Figure 5 is a structure schematic diagram of a power supply system provided by the embodiment of the present application. DETAILED DESCRIPTION

[0019] In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular architectures, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known methods, devices, circuits, and

[0020] In order to make the objects, technical solutions and advantages of the present application clearer, the following will be described in conjunction with the specific embodiments and the accompanying drawings.

[0021] Referring to Figure 2 , it shows an implementation flowchart of a control method of a converter provided by an embodiment of the present application. The control method of the converter is applied to a bidirectional converter; wherein, referring to Figure 1 , the first port of the bidirectional converter is provided with a first capacitor C1, and the second port of the bidirectional converter is provided with a second capacitor C2;

[0022] The control method is described in detail as follows:

[0023] S101: obtaining the voltage effective value of the first port and the voltage effective value of the second port;

[0024] S102: if the voltage effective value of the first port is greater than a first preset voltage, or the voltage effective value of the second port is greater than a second preset voltage, then controlling the bidirectional converter to alternately work in a first conversion state and a second conversion state until the voltage effective value of the first port is not greater than the first preset voltage, and the voltage effective value of the second port is not greater than the second preset voltage.

[0025] The control method of the converter provided by the embodiment of the present application is applied to a bidirectional converter, and the switches inside the bidirectional converter are controlled to control the bidirectional converter to alternately work in a first conversion state and a second conversion state (for example, the boost state and the buck state of a direct current converter), so as to form a discharge path, so that the energy is continuously exchanged between the first capacitor C1 and the second capacitor C2. As the energy flows, a current path is formed, and energy is consumed. With the continuous exchange of energy between the first capacitor C1 and the second capacitor C2, the internal stored energy is continuously consumed by the internal devices (for example, the internal switches) of the bidirectional converter, until the port voltage meets the requirement.

[0026] The embodiment of the present application controls the two ports of the bidirectional converter to continuously exchange energy to consume the residual energy, without the need to set a separate discharge circuit, thereby greatly reducing the complexity of the circuit. Moreover, the control is performed by using the control logic itself, without the need to write a separate control logic, so that the control method is simple and effective, and the development cost is reduced.

[0027] It should be noted that the first preset voltage and the second preset voltage are safety voltages; when the first port and the second port are both connected to external devices through the switches, the preset voltage (the first preset voltage or the second preset voltage) can be determined by the pressure difference allowed to be closed by the corresponding switch. It is not limited here, and can be set according to actual application requirements.

[0028] In a possible embodiment, the bidirectional converter can be a bidirectional DCDC or a bidirectional ACDC.

[0029] The embodiment of the application is not limited to bidirectional DCDC. For bidirectional DCDC or bidirectional ACDC, both of them are usually provided with capacitors at two ports, and the left and right two ports are respectively connected to other devices. When the connection of the left and right two ports to the outside is cut off, there is no discharge path, and the energy stored in the first capacitor and the second capacitor has no place to discharge. Both types of bidirectional converters have the problem of energy having no place to discharge, and both have two working states and can work bidirectionally.

[0030] In a possible implementation, the bidirectional converter is a bidirectional DCDC, the first conversion state can be a boost state, and the second conversion state can be a buck state. Or, the first conversion state is a buck state, and the second conversion state is a boost state.

[0031] Further, the bidirectional converter is a bidirectional ACDC, the first conversion state can be an inverter state, and the second conversion state is a rectifier state. Or, the first conversion state is a rectifier state, and the second conversion state is an inverter state.

[0032] Illustratively, the bidirectional DCDC can be an isolated bidirectional DCDC or a non-isolated bidirectional ACDC; the bidirectional ACDC can also be an isolated bidirectional ACDC or a non-isolated bidirectional ACDC;

[0033] Based on the architecture of the bidirectional ACDC, the bidirectional ACDC can also be an I-type three-level ACDC or a T-type three-level ACDC.

[0034] The circuit structure of the bidirectional DCDC and the bidirectional ACDC includes but is not limited to the above several structures. Any structure of the bidirectional DCDC or the bidirectional ACDC has a first capacitor C1 and a second capacitor C2, and can apply the above control method for energy discharge.

[0035] In a possible implementation, the bidirectional converter alternately works in the first conversion state and the second conversion state can be continuously alternately working in the first conversion state and the second conversion state, or intermittently alternately working in the first conversion state and the second conversion state, or other alternating modes.

[0036] The bidirectional converter alternately works in the first conversion state and the second conversion state to flow energy between the first capacitor C1 and the second capacitor C2, forming an energy consumption path, without being limited to a specific alternating manner, as long as a path for energy flow is formed.

[0037] More specifically, in one possible implementation, controlling the bidirectional converter to work in the first conversion state can include:

[0038] S1021: obtaining a voltage effective value of the second port at the current moment, and determining a first given voltage according to the voltage effective value of the second port at the current moment;

[0039] S1022: controlling the bidirectional converter to work in the first conversion state for a first preset time length with the first given voltage as an output voltage given value;

[0040] Controlling the bidirectional converter to work in the second conversion state can include:

[0041] S1023: obtaining a voltage effective value of the first port at the current moment, and determining a second given voltage according to the voltage effective value of the first port at the current moment;

[0042] S1024: controlling the bidirectional converter to work in the second conversion state for a second preset time length with the second given voltage as the output voltage given value;

[0043] Wherein, when the bidirectional converter works in the first conversion state, energy of the first capacitor C1 flows to the second capacitor C2; and when the bidirectional converter works in the second conversion state, energy of the second capacitor C2 flows to the first capacitor C1.

[0044] In one possible implementation, the voltage effective value of the second port at the current moment is less than the first given voltage, and the voltage effective value of the first port at the current moment is less than the second given voltage.

[0045] Reference Figure 1 When the bidirectional converter works in the first conversion state, energy flows from the first capacitor C1 to the second capacitor C2, and the output voltage given value of the loop control when the bidirectional converter works in the first conversion state should be higher than the voltage effective value of the current second capacitor C2, forming a pressure difference, so that energy can flow from the first capacitor C1 to the second capacitor C2. Similarly, the output voltage given value when the bidirectional converter works in the second conversion state is determined according to the voltage effective value of the first port.

[0046] Meanwhile, in the embodiment of the present application, each conversion state has a fixed time length, the alternating process is stable, and the control is simple.

[0047] For example, the first preset time length and the second preset time length can be the same, and the control method is simple.

[0048] But due to the different capacitances of the first port and the second port, the current is large in 3-5 charging cycles based on the capacitance characteristics, so the working time can be set to 3-5 charging cycles to ensure large current work and improve the efficiency of energy discharge.

[0049] In a possible implementation, the first preset time length can be in the range of 3R2C2-5R2C2, and the second preset time length can be in the range of 3R1C1-5R1C1.

[0050] Wherein, R1 is the equivalent charging resistance of the first capacitor C1, and C1 is the capacitance value of the first capacitor C1; R2 is the equivalent charging resistance of the second capacitor C2, and C2 is the capacitance value of the second capacitor C2.

[0051] When the bidirectional converter is a bidirectional DCDC, and the first conversion state is a step-down state and the second conversion state is a step-up state, the voltage of the first port is greater than the voltage of the second port, and the first preset time length can be greater than the second preset time length.

[0052] In another possible implementation, the control of the bidirectional converter working in the first conversion state can include:

[0053] S1025: Control the bidirectional converter to work in the first conversion state;

[0054] S1026: Real-time acquisition of the voltage effective value of the first port;

[0055] S1027: If the change rate of the voltage effective value of the first port is less than the first preset change rate, control the bidirectional converter to exit the first conversion state;

[0056] The control of the bidirectional converter working in the second conversion state includes:

[0057] S1028: Control the bidirectional converter to work in the second conversion state;

[0058] S1029: Real-time acquisition of the voltage effective value of the second port;

[0059] S1030: If the change rate of the voltage effective value of the second port is less than the second preset change rate, control the bidirectional converter to exit the second conversion state.

[0060] In the control method of S1021-S1024, the output voltage is given constant in two conversion states, but as the work goes on, the input voltage drop becomes smaller and smaller, the current also becomes smaller and smaller, and the device energy consumption also decreases, so it is meaningless to continue working in the conversion state.

[0061] For example, when the bidirectional converter works in the first conversion state, as the work goes on, the rate of change of the voltage effective value of the first port is less than the first preset rate of change, which indicates that the energy flow is already very small, and it is not very meaningful to continue to maintain the first conversion state, and the second conversion state can be switched. Similarly, when the rate of change of the voltage effective value of the second port is detected to be less than the second preset rate of change, the first conversion state is switched, so that the energy flow is more efficient, and the speed of energy consumption is improved.

[0062] It should be noted that the first preset rate of change and the second preset rate of change can be different, and can be determined according to the port capacitance. For example, the bidirectional converter is a bidirectional DCDC, the first conversion state is a buck state, and the second conversion state is a boost state. Then the voltage of the second capacitor C2 is higher, and the voltage of the first capacitor C1 is lower, and the first preset rate of change can be greater than the second preset rate of change.

[0063] In a possible implementation, the method of controlling the bidirectional converter to work in the first conversion state can further include:

[0064] S1031: Obtain the voltage effective value of the second port once every preset number of PWM periods, and determine the third given voltage corresponding to this time according to the voltage effective value of the second port obtained this time, and adjust the output given of the bidirectional converter working in the first conversion state to the third given voltage corresponding to this time;

[0065] The method of controlling the bidirectional converter to work in the second conversion state can further include:

[0066] S1032: Obtain the voltage effective value of the first port once every preset number of PWM periods, and determine the fourth given voltage corresponding to this time according to the voltage effective value of the first port obtained this time, and adjust the output given of the bidirectional converter working in the second conversion state to the fourth given voltage corresponding to this time.

[0067] For example, when in the first conversion state, as the loop control runs, the difference between the voltage effective value of the second port and the output voltage given value becomes smaller and smaller, and the current also becomes smaller and smaller. Based on this, in the embodiment of the application, the output voltage given value can be dynamically adjusted according to the voltage effective value of the port, so that the voltage effective value of the port and the output voltage given value always maintain a large difference, the rate of energy flow is improved, and the speed of energy discharge is improved.

[0068] In a possible implementation, the bidirectional DC-DC converter can be a flying capacitor type buck-boost converter.

[0069] It should be understood that the magnitude of the serial number of each step in the above embodiments does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0070] The following is an apparatus embodiment of the present application. For details not described in detail, reference can be made to the corresponding method embodiments described above.

[0071] Figure 3 The structure of the control device of the converter provided by the embodiment of the present application is shown in the schematic diagram. The above device is applied to a bidirectional converter; wherein, referring to Figure 1 , the first port of the bidirectional converter is provided with a first capacitor C1, and the second port of the bidirectional converter is provided with a second capacitor C2; for the convenience of description, only the part related to the embodiment of the present application is shown, and the details are as follows:

[0072] As Figure 3 shown, the control device of the converter comprises:

[0073] The voltage acquisition module 21 is configured to acquire the voltage effective value of the first port and the voltage effective value of the second port;

[0074] The alternating control module 22 is configured to control the bidirectional converter to alternately work in the first conversion state and the second conversion state if the voltage effective value of the first port is greater than the first preset voltage, or the voltage effective value of the second port is greater than the second preset voltage, until the voltage effective value of the first port is not greater than the first preset voltage, and the voltage effective value of the second port is not greater than the second preset voltage.

[0075] In a possible implementation, the alternating control module 22 can comprise:

[0076] The first given voltage determination unit is configured to acquire the voltage effective value of the second port at the current moment, and determine the first given voltage according to the voltage effective value of the second port at the current moment;

[0077] The first loop control unit is configured to control the bidirectional converter to work in the first conversion state for a first preset time length with the first given voltage as the output voltage given value;

[0078] The second given voltage determination unit is configured to acquire the voltage effective value of the first port at the current moment, and determine the second given voltage according to the voltage effective value of the first port at the current moment;

[0079] The second loop control unit is configured to control the bidirectional converter to work in the second conversion state for a second preset time length with the second given voltage as the output voltage given value;

[0080] Wherein, when the bidirectional converter works in the first conversion state, the energy of the first capacitor C1 flows to the second capacitor C2; when the bidirectional converter works in the second conversion state, the energy of the second capacitor C2 flows to the first capacitor C1.

[0081] In a possible implementation, the voltage effective value of the second port at the current moment is less than the first given voltage, and the voltage effective value of the first port at the current moment is less than the second given voltage.

[0082] In a possible implementation, the alternating control module 22 can include:

[0083] a third loop control unit configured to control the bidirectional converter to work in the first conversion state;

[0084] a third voltage acquisition unit configured to acquire the voltage effective value of the first port in real time;

[0085] a first mode switching unit configured to control the bidirectional converter to exit the first conversion state if the rate of change of the voltage effective value of the first port is less than the first preset rate of change;

[0086] a fourth loop control unit configured to control the bidirectional converter to work in the second conversion state;

[0087] a fourth voltage acquisition unit configured to acquire the voltage effective value of the second port in real time;

[0088] a second mode switching unit configured to control the bidirectional converter to exit the second conversion state if the rate of change of the voltage effective value of the second port is less than the second preset rate of change.

[0089] In a possible implementation, the alternating control module 22 can further include:

[0090] a first given adjustment unit configured to acquire the voltage effective value of the second port once every preset number of PWM periods, and determine the third given voltage corresponding to this time according to the voltage effective value of the second port acquired this time, and adjust the output given of the bidirectional converter working in the first conversion state to the third given voltage corresponding to this time;

[0091] a second given adjustment unit configured to acquire the voltage effective value of the first port once every preset number of PWM periods, and determine the fourth given voltage corresponding to this time according to the voltage effective value of the first port acquired this time, and adjust the output given of the bidirectional converter working in the second conversion state to the fourth given voltage corresponding to this time.

[0092] In a possible implementation, the bidirectional converter can be a bidirectional direct current converter, the first conversion state can be a boost state, and the second conversion state can be a buck state.

[0093] In a possible implementation, the bidirectional DC converter can be a flying capacitor type buck-boost converter.

[0094] Figure 4 is a schematic diagram of a control terminal provided by an embodiment of the present application. As shown in Figure 4 the control terminal 3 of this embodiment includes a processor 30 and a memory 31. The memory 31 is configured to store a computer program 32, and the processor 30 is configured to invoke and run the computer program 32 stored in the memory 31 to perform the steps in the control method embodiments of the various converters described above, such as Figure 2 steps S101-S102 shown in Figure 3 Alternatively, the processor 30 is configured to invoke and run the computer program 32 stored in the memory 31 to implement the functions of the various modules / units in the various device embodiments described above, such as the functions of the modules 21-22 shown in

[0095] For example, the computer program 32 can be divided into one or more modules / units, one or more of which are stored in the memory 31 and executed by the processor 30 to complete the present application. One or more modules / units can be a series of computer program instruction segments capable of completing a specific function, which are used to describe the execution process of the computer program 32 in the control terminal 3. For example, the computer program 32 can be divided into Figure 3 modules / units 21-22 shown in

[0096] The control terminal 3 can be a desktop computer, a notebook, a palm computer, a cloud server, and the like. The control terminal 3 can include, but is not limited to, the processor 30, the memory 31. Those skilled in the art can understand that Figure 4 the control terminal 3 is merely an example and does not constitute a limitation on the control terminal 3, and can include more or fewer components than those shown, or combine certain components, or different components, for example, the terminal can also include input / output devices, network access devices, buses, and the like.

[0097] The processor 30 can be a central processing unit (CPU), and can also be other general-purpose processors, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0098] The memory 31 can be an internal storage unit of the terminal 3, for example, a hard disk or a memory of the terminal 3. The memory 31 can also be an external storage device of the terminal 3, for example, a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the terminal 3. Further, the memory 31 can include both the internal storage unit and the external storage device of the terminal 3. The memory 31 is used to store computer programs and other programs and data required by the terminal. The memory 31 can also be used to temporarily store data that has been output or is to be output.

[0099] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above functional units and modules is exemplified, and in actual application, the above functions can be completed by different functional units and modules according to needs, that is, the internal structure of the device is 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 one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit, and the integrated unit can be realized in the form of hardware or in the form of software functional unit. In addition, the specific names of each functional unit and module are only for easy distinction, and do not limit the protection scope of the present application. The specific working process of the units and modules in the above system can refer to the corresponding process in the foregoing method embodiments, which will not be described here.

[0100] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described or recorded in detail in a certain embodiment can be referred to the relevant description of other embodiments.

[0101] Those skilled in the art can understand that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0102] In the embodiments provided by the present application, it should be understood that the disclosed apparatus / terminal and method can be implemented in other ways. For example, the apparatus / terminal embodiments described above are merely schematic. For example, the division of the modules or units is merely a logical function division, and there can be another division manner in actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed coupling or direct coupling or communication connection between the units can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or in other forms.

[0103] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e. can be located in one place, or can be distributed on a plurality of network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiments.

[0104] In addition, each functional unit in each embodiment of the present application can be integrated into a processing unit, or each unit can exist physically independently, or two or more units can be integrated into one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0105] The integrated module / unit, if implemented in the form of a software function unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on such an understanding, all or part of the processes in the above-mentioned embodiment methods can also be completed by a computer program instructing related hardware, and 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-mentioned various method embodiments can be implemented. The computer program includes computer program code, which can be in the form of source code, object code, an executable file, or some intermediate form. The computer-readable medium can include any entity or device capable of carrying computer program code, a recording medium, a U disk, a mobile hard disk, a magnetic disk, an optical disk, a computer memory, a read-only memory (Read-Only Memory, ROM), a random access memory (Random Access Memory, RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0106] Corresponding to the above-mentioned embodiments, with reference to Figure 5 The embodiment of the present application also provides an energy storage system, comprising: a direct current power supply and a bidirectional converter; wherein a first port of the bidirectional converter is provided with a first capacitor C1, and a second port of the bidirectional converter is provided with a second capacitor C2;

[0107] The first port of the bidirectional converter is connected with an external device, and the second port of the bidirectional converter is connected with the direct current power supply;

[0108] When the bidirectional converter is in the bleeder state machine, the bidirectional converter applies the steps of the converter control method provided in the above-mentioned embodiments;

[0109] When the bidirectional converter exits the bleeder state machine, the bidirectional converter does not apply the steps of the converter control method provided in the above-mentioned embodiments;

[0110] When the bidirectional converter is applied to the energy storage system, the bleeder state machine is set, and when the bidirectional converter is in the bleeder state machine, the control method in the above-mentioned embodiments is executed to perform energy bleeder, otherwise it is not executed, so as to avoid the existence of intersection with other control logics when the bidirectional converter is in the non-state bleeder machine, and affect the execution of normal work.

[0111] In a possible implementation, the bidirectional converter can be a bidirectional direct current converter, and the direct current power supply can be a battery.

[0112] In a possible implementation, the energy storage system can further comprise a switch;

[0113] The first port of the bidirectional converter is connected with an external device through the switch;

[0114] After the steps of the control method of the converter provided by the above embodiments are performed on the bidirectional converter, the switch is closed.

[0115] In the embodiment of the present application, the first port is connected with the external device through the switch, and the control method in the above embodiment is used for energy discharge, so that the switch cannot be closed when the pressure difference between the two sides of the switch is too large, and the robustness and safety of the power supply system are improved.

[0116] The above embodiments are only used to illustrate the technical solutions of the present application, but not limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A control method for a converter, characterized in that, The method is applied to a bidirectional converter; wherein a first capacitor is provided at the first port of the bidirectional converter, and a second capacitor is provided at the second port of the bidirectional converter; the control method includes: Obtain the effective voltage value of the first port and the effective voltage value of the second port; If the effective voltage value of the first port is greater than the first preset voltage, or the effective voltage value of the second port is greater than the second preset voltage, then the bidirectional converter is controlled to alternately operate in the first conversion state and the second conversion state until the effective voltage value of the first port is not greater than the first preset voltage and the effective voltage value of the second port is not greater than the second preset voltage. The control of the bidirectional converter to operate in the first conversion state includes: Obtain the effective voltage value of the second port at the current moment, and determine the first given voltage based on the effective voltage value of the second port at the current moment; The first given voltage is used as the output voltage given value to control the bidirectional converter to operate in the first conversion state for a first preset duration; Controlling the bidirectional converter to operate in the second conversion state includes: Obtain the effective voltage value of the first port at the current moment, and determine the second given voltage based on the effective voltage value of the first port at the current moment; The second given voltage is used as the output voltage given value to control the bidirectional converter to operate in the second conversion state for a second preset duration; Wherein, when the bidirectional converter operates in the first conversion state, the energy of the first capacitor flows to the second capacitor; when the bidirectional converter operates in the second conversion state, the energy of the second capacitor flows to the first capacitor; or The control of the bidirectional converter to operate in the first conversion state includes: The bidirectional converter is controlled to operate in the first conversion state; The effective voltage value of the first port is obtained in real time; If the rate of change of the effective voltage value at the first port is less than the first preset rate of change, then the bidirectional converter is controlled to exit the first conversion state. Controlling the bidirectional converter to operate in the second conversion state includes: Control the bidirectional converter to operate in the second conversion state; The effective voltage value of the second port is obtained in real time; If the rate of change of the effective voltage value at the second port is less than the second preset rate of change, then the bidirectional converter is controlled to exit the second conversion state.

2. The control method for the converter according to claim 1, characterized in that, The effective voltage value of the second port at the current moment is less than the first given voltage, and the effective voltage value of the first port at the current moment is less than the second given voltage.

3. The control method for the converter according to claim 1, characterized in that, The method of controlling the bidirectional converter to operate in the first conversion state further includes: At a preset number of PWM cycles, the effective voltage value of the second port is acquired once, and the third given voltage corresponding to this time is determined based on the effective voltage value of the second port acquired this time. The output given of the bidirectional converter operating in the first conversion state is adjusted to the third given voltage corresponding to this time. The method of controlling the bidirectional converter to operate in the second conversion state further includes: Every preset number of PWM cycles, the effective voltage value of the first port is acquired once, and the corresponding fourth given voltage is determined based on the acquired effective voltage value of the first port. The output given of the bidirectional converter operating in the second conversion state is adjusted to the corresponding fourth given voltage.

4. The control method for the converter according to any one of claims 1 to 3, characterized in that, The bidirectional converter is a bidirectional DC-DC converter, with the first conversion state being a boost state and the second conversion state being a buck state.

5. The control method for the converter according to claim 4, characterized in that, The bidirectional DC-DC converter is a flying capacitor type buck-boost converter.

6. An energy storage system, characterized in that, include: A DC power supply and a bidirectional converter; wherein, a first capacitor is provided at the first port of the bidirectional converter, and a second capacitor is provided at the second port of the bidirectional converter; The first port of the bidirectional converter is connected to an external device, and the second port of the bidirectional converter is connected to the DC power supply. When the bidirectional converter is in the bleed state machine, the bidirectional converter applies the steps of the control method of the converter as described in any one of claims 1 to 5; When the bidirectional converter exits the discharge state machine, the bidirectional converter does not apply the steps of the control method of the converter as described in any one of claims 1 to 5.

7. The energy storage system according to claim 6, characterized in that, The bidirectional converter is a bidirectional DC-DC converter, and the DC power source is a battery.

8. The energy storage system according to claim 7, characterized in that, The energy storage system also includes: a switch; The first port of the bidirectional converter is connected to the external device via the switch; After executing the steps of the control method of the bidirectional converter on the bidirectional converter, the switch is controlled to close.

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