Voltage converter and method of operating the same, energy storage converter and computer readable storage medium

Abstract

This application provides a voltage converter and its operating method, an energy storage converter, and a computer-readable storage medium, belonging to the field of energy storage. The voltage converter includes a four-switch buck-boost circuit and a controller. The first terminal of the four-switch buck-boost circuit is connected to a battery module, and the second terminal is connected to an electrical device. The controller is connected to the four-switch buck-boost circuit and configured to acquire the input voltage at the first terminal and control the four-switch buck-boost circuit to switch according to the input voltage at the first terminal, thereby controlling the output voltage at the second terminal. This application reduces the switching losses of the voltage converter in high-voltage scenarios with a wide output voltage range of liquid metal batteries.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, specifically to a voltage converter and its operating method, an energy storage converter, and a computer-readable storage medium. Background Technology

[0002] Liquid metal batteries (LMBs) are characterized by a wide output voltage range. When used in energy storage, their application can affect the operation of inverters in the system, thus impacting the overall efficiency of the energy storage system. Therefore, a voltage converter is typically required between the LMB and the inverter to convert the wide output voltage range of the LMB. However, in high-voltage scenarios with the wide output voltage range of LMBs, the voltage converter suffers from significant switching losses. Summary of the Invention

[0003] This application provides a voltage converter and its operating method, an energy storage converter, and a computer-readable storage medium for reducing switching losses in high-voltage scenarios with a wide output voltage range of liquid metal batteries.

[0004] In a first aspect, embodiments of this application provide a voltage converter, including a four-switch buck-boost circuit and a controller. A first terminal of the four-switch buck-boost circuit is connected to a battery assembly, and a second terminal is connected to an electrical device. The controller is connected to the four-switch buck-boost circuit and configured to acquire the input voltage at the first terminal and control the four-switch buck-boost circuit to perform switching conversions based on the input voltage at the first terminal, thereby controlling the voltage output at the second terminal. Specifically, corresponding to an input voltage in a first voltage range, the four-switch buck-boost circuit performs a hard-switching boost conversion to control the second terminal to output a first voltage; corresponding to an input voltage in a second voltage range, the four-switch buck-boost circuit performs a soft-switching buck conversion to control the second terminal to output a first voltage; corresponding to an input voltage in a third voltage range, the second terminal directly outputs the input voltage. The first, second, and third voltage ranges are continuous, with the third voltage range between the first and second voltage ranges; the first voltage is between the maximum value in the first voltage range and the minimum value in the second voltage range.

[0005] In this embodiment, when the input voltage is in the low-voltage first voltage range, the four-switch buck-boost circuit can perform hard-switching boost conversion under the control of the controller, thereby significantly reducing control complexity and hardware cost, and making losses controllable. When the input voltage is in the high-voltage second voltage range, the four-switch buck-boost circuit can perform soft-switching buck conversion under the control of the controller, avoiding the high losses and high voltage stress of high-voltage hard switching, thereby optimizing the problem of large switching losses. When the input voltage is in the medium-voltage third voltage range, the four-switch buck-boost circuit can perform pass-through topology conversion under the control of the controller, thereby eliminating switching losses and significantly improving energy transfer efficiency.

[0006] In one possible embodiment, the four-switch buck-boost circuit includes a first switch, a second switch, a third switch, a fourth switch, and an inductor. The first terminal of the first switch is connected to the first terminal of the four-switch buck-boost circuit; the second terminal of the first switch is connected to the first terminal of the second switch and the first terminal of the inductor; the second terminal of the second switch is grounded; the first and second terminals of the third switch are connected; the second terminal of the third switch is connected to the second terminal of the inductor and the first terminal of the fourth switch; and the second terminal of the fourth switch is connected to the second terminal of the second switch.

[0007] In one possible embodiment, corresponding to the input voltage in the first voltage range, the controller keeps the first switch on, keeps the second switch off, and controls the third and fourth switches to alternately turn on and off, with the third and fourth switches not turning on simultaneously, forming a hard-switching boost converter. The fourth switch is directly turned off from the on state, and the inductor current rapidly commutates from the fourth switch to the third switch. The voltage across the fourth switch rises rapidly to the output voltage, resulting in a significant voltage-current overlap region and substantial turn-off losses. During the turn-on process, the fourth switch is driven to turn on before the voltage across it drops to zero, thus current and voltage coexist at the moment of turn-on, generating turn-on losses. The third switch, as a synchronous rectifier, also exhibits a voltage-current overlap region during turn-on and turn-off, generating hard-switching losses. Since the voltage stress on the switches in the first voltage range is much lower than in the second voltage range, the absolute value of the hard-switching losses is relatively small, significantly reducing control complexity and hardware costs. This achieves an optimal balance between engineering implementation difficulty, reliability, and efficiency while ensuring acceptable efficiency.

[0008] In one possible embodiment, corresponding to the input voltage in the second voltage range, the controller controls the first, second, third, and fourth switches to alternately turn on and off. During a first time period, the first and fourth switches are turned on, while the second and third switches are turned off; during a second time period, the first and third switches are turned on, while the second and fourth switches are turned off; during a third time period, the second and third switches are turned on, while the first and fourth switches are turned off; and during a fourth time period, the second and fourth switches are turned on, while the first and third switches are turned off, thus forming a soft-switching buck converter. The negative inductor current maintained during the fourth time period is used to charge and discharge the junction capacitance of the switches during the dead time of switching. Before the first and fourth main switching transistors are turned on, their junction capacitances discharge to zero through the negative current of the inductor, reducing the voltage between the first and second terminals to zero, thus achieving zero-voltage turn-on. Similarly, before the second and third synchronous rectifier transistors are turned on, their junction capacitances also discharge through the inductor current, achieving zero-voltage turn-on. There is no voltage-current overlap region during the turn-on process of any of the switching transistors, eliminating turn-on losses, significantly reducing total switching losses, and ensuring the efficiency and reliability of the converter within the second voltage range of the input voltage. The first, second, third, and fourth time periods are performed cyclically.

[0009] In one possible embodiment, corresponding to the input voltage being in the third voltage range, the controller controls the first and third switches to turn on, while the second and fourth switches turn off, forming a switch-through topology conversion. During this process, all switches remain in a fixed state, with no high-frequency pulse width modulation (PWM) action, eliminating switching and drive losses; the inductor is short-circuited, eliminating inductor current ripple, and significantly reducing magnetic component losses and noise; the output voltage is essentially the same as the input voltage, eliminating the need for voltage regulation control, simplifying the control logic, minimizing system losses, improving converter efficiency and reliability, and avoiding unnecessary switching and energy transfer stages.

[0010] Secondly, this application provides an operation method for a voltage converter. The voltage converter includes a four-switch buck-boost circuit and a controller. The operation method includes: the controller acquiring the input voltage at the first terminal of the four-switch buck-boost circuit; corresponding to the input voltage being within a first voltage range; controlling the four-switch buck-boost circuit to perform hard-switching boost conversion; controlling the second terminal of the four-switch buck-boost circuit to output a first voltage; corresponding to the input voltage being within a second voltage range; controlling the four-switch buck-boost circuit to perform soft-switching buck conversion; controlling the second terminal to output the first voltage; corresponding to the input voltage being within a third voltage range; controlling the four-switch buck-boost circuit to perform a pass-through topology conversion; controlling the second terminal to directly output the input voltage. The first terminal of the four-switch buck-boost circuit is used to connect to a battery assembly, and the second terminal is used to connect to electrical equipment; the first voltage is between the maximum value in the first voltage range and the minimum value in the second voltage range.

[0011] Thirdly, embodiments of this application provide an energy storage converter, which includes a DC side, an AC side, an inverter, and the voltage converter mentioned in the first aspect above, wherein the DC side, the voltage converter, the inverter, and the AC side are connected in sequence.

[0012] Fourthly, embodiments of this application provide a computer-readable storage medium storing computer-executable instructions, which, when executed, can implement the operation method described in the second aspect above.

[0013] It should be understood that the technical effects of the methods in the second to fourth aspects can be referred to the first aspect, and the implementation methods of this application will not be described again here. Attached Figure Description

[0014] Figure 1 A schematic diagram of a voltage converter provided for an embodiment of this application; Figure 2 A schematic flowchart illustrating an operation method of a voltage converter provided in this application embodiment; Figure 3 A schematic diagram of the current flow direction of a four-switch buck-boost circuit under hard-switching boost operation during the inductor energy storage stage, provided for an embodiment of this application. Figure 4 A schematic diagram of the current flow direction of a four-switch buck-boost circuit in the inductor energy release boost stage under hard-switching boost operation, provided for an embodiment of this application. Figure 5 A waveform diagram of the inductor current in each mode under soft-switching condition of a four-switch buck-boost circuit provided for the embodiments of this application; Figure 6A schematic diagram of the current flow direction of a four-switch buck-boost circuit under the charging mode of soft-switching buck operation, provided for the embodiments of this application; Figure 7 A schematic diagram of the current flow direction of a four-switch buck-boost circuit in the power direct transmission mode under soft-switching buck operation, provided for an embodiment of this application. Figure 8 A schematic diagram of the current flow direction of a four-switch buck-boost circuit under the reset mode of soft-switching buck operation, provided for the embodiments of this application; Figure 9 A schematic diagram of the current flow direction of a four-switch buck-boost circuit in the freewheeling mode under soft-switching buck operation, provided for an embodiment of this application. Figure 10 A schematic diagram of the current flow of a four-switch buck-boost circuit in a through-type topology, provided for embodiments of this application; Figure 11 A schematic diagram of an energy storage converter provided for an embodiment of this application.

[0015] Figure reference numerals: 100, voltage converter; 110, four-switch buck-boost circuit; 200, energy storage converter; 210, DC side; 220, inverter; 230, AC side. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0017] The terms "first" and "second" used in the embodiments of this application are only used to distinguish features of the same type and should not be construed as indicating relative importance, quantity, order, etc.

[0018] The terms "exemplary" or "for example" used in the embodiments of this application are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0019] The term "connection" used in the embodiments of this application should be interpreted broadly. For example, it can refer to a physical direct connection or an indirect connection implemented through electronic devices, such as a connection implemented through resistors, inductors, capacitors or other electronic devices.

[0020] Liquid metal batteries (LMBs) are characterized by a wide output voltage range. When used in energy storage, their application can affect the operation of inverters in the system, thus impacting the overall efficiency of the energy storage system. Therefore, a voltage converter is typically required between the LMB and the inverter to convert the wide output voltage range of the LMB. However, in high-voltage scenarios with the wide output voltage range of LMBs, the voltage converter suffers from significant switching losses.

[0021] Therefore, this application provides a voltage converter. For example... Figure 1 As shown, the voltage converter 100 includes a controller (not shown) and a four-switch buck-boost circuit 110. A first terminal of the four-switch buck-boost circuit 110 is used to connect to a battery assembly, such as a liquid metal battery. A second terminal of the four-switch buck-boost circuit 110 is used to connect to an electrical device, such as an inverter.

[0022] Please continue to refer to Figure 1 The four-switch buck-boost circuit 110 includes a first switch S1, a second switch S2, a third switch S3, a fourth switch S4, an inductor L, and an input capacitor C. in and output capacitor C o In this circuit, the first terminal of the first switch S1 is connected to the first terminal of the four-switch buck-boost circuit 110, the second terminal of the first switch S1 is connected to the first terminal of the second switch S2, and the second terminal of the second switch S2 is grounded. Specifically, the first terminal of the first switch S1 is used to connect to the positive terminal of the liquid metal battery, and the negative terminal of the liquid metal battery can be grounded. That is to say, grounding the second terminal of the second switch S2 means that the second terminal of the second switch S2 is used to connect to the negative terminal of the liquid metal battery. Input capacitor C in The first terminal is connected to the first terminal of the first switching transistor S1, and the input capacitor C in The second terminal is connected to the second terminal of the second switching transistor S2.

[0023] The first terminal of the third switch S3 is connected to the second terminal of the four-switch buck-boost circuit 110. The second terminal of the third switch S3 is connected to the first terminal of the fourth switch S4. The second terminal of the fourth switch S4 is connected to the second terminal of the second switch S2. Specifically, the first terminal of the third switch S3 is connected to the positive input terminal of the inverter, and the second terminal of the fourth switch S4 is connected to the negative input terminal of the inverter. Output capacitor C o The first terminal is connected to the first terminal of the third switch S3, and the output capacitor C o The second terminal is connected to the second terminal of the fourth switch S4.

[0024] The first end of the inductor L is connected to the connection node of the first switch S1 and the second switch S2, and the second end of the inductor L is connected to the connection node of the third switch S3 and the fourth switch S4.

[0025] The controller has at least one input terminal and four output terminals. One input terminal is connected to the first terminal of the four-switch buck-boost circuit 110, and the four output terminals are respectively connected to the control terminals of the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4. The controller is used to control the on / off state of the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4 based on the input voltage obtained from the first terminal of the four-switch buck-boost circuit 110.

[0026] The controller can employ different control strategies to control the switching on and off of the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4 based on the acquired input voltage; that is, different input voltages require different control strategies. In some examples, the controller may include a processing unit, which includes, but is not limited to, a central processing unit (CPU), a digital signal processor (DSP), a microcontroller unit (MCU), and a field-programmable gate array (FPGA).

[0027] This application provides an operating method for a voltage converter, which includes a four-switch buck-boost circuit and a controller. The controller can execute this operating method to optimize the problem of high switching losses in the four-switch buck-boost circuit. Figure 2 As shown, the operation method includes S110-S140, as follows: S110, The controller obtains the input voltage at the first terminal of the four-switch buck-boost circuit.

[0028] like Figure 1 As shown, the first terminal is used to connect to the battery assembly. The controller obtains the input voltage of the first terminal of the four-switch buck-boost circuit 110, which is also the terminal voltage of the battery assembly; that is, the voltage difference between the positive and negative terminals of the battery assembly. In some embodiments, the battery assembly can be composed of multiple cells connected in series and parallel. In some embodiments, the controller integrates an analog-to-digital converter (ADC), which can sample the input voltage; for example, the sampling frequency of the ADC can be once per second.

[0029] S120, corresponding to the input voltage being within the first voltage range, the controller performs hard-switching boost conversion by controlling the four-switch buck-boost circuit, and controls the second terminal of the four-switch buck-boost circuit to output the first voltage.

[0030] like Figure 1 As shown, the second terminal is used to connect to electrical equipment and supply power to it. When the input voltage is in the first voltage range, the controller controls the four-switch buck-boost circuit 110 to boost the input voltage; that is, the first voltage is greater than the maximum value of the first voltage range. In some examples, the first voltage range can be 200V-700V, and the first voltage is 750V.

[0031] Specifically, the controller can keep the first switch S1 continuously on, thereby directly electricalally connecting the positive terminal of the input voltage to the first terminal of the inductor L, forming a fixed conduction path. Simultaneously, the controller also keeps the second switch S2 continuously off, completely blocking the freewheeling path on the buck side, rendering the buck-side topology ineffective, and avoiding interference with the boost converter. Furthermore, the controller can alternately switch the third switch S3 and the fourth switch S4 according to the high-frequency PWM logic of the boost converter, where the fourth switch S4 is the main switch with a duty cycle (D), and the third switch S3 has a duty cycle of 1. The synchronous rectifier diode D is controlled by the controller to output the first voltage at the second terminal.

[0032] Combination Figure 1 In the four-switch buck-boost topology shown, during hard-switching boost conversion, the buck-side switches of the four-switch buck-boost circuit 110, including the first switch S1 and the second switch S2, serve only as fixed conduction paths. The boost-side switches of the four-switch buck-boost circuit 110, including the third switch S3, the fourth switch S4, the inductor L, and the output capacitor C, are... o Together, they constitute a boost converter, with a highly simplified topology and control logic, retaining only the core boost conversion function. Specifically, such as... Figure 3 and Figure 4 As shown, the controller controls the four-switch buck-boost circuit 110 to perform hard-switching boost conversion, including an inductor energy storage stage and an inductor energy release boost stage.

[0033] like Figure 3 As shown, during the inductor energy storage stage, the first switch S1 remains on, the second switch S2 remains off, the third switch S3 remains off, and the fourth switch S4 remains on. The current path is as follows: current flows from the positive terminal of the battery module through the first switch S1, the inductor L, and the fourth switch S4 back to the negative terminal of the input battery module. During this stage, the battery module charges the inductor L, and the inductor L stores energy.

[0034] like Figure 4As shown, during the inductor-driven energy release boost stage, the first switch S1 remains on, the second switch S2 remains off, the third switch S3 is on, and the fourth switch S4 is off. The current path is from the positive terminal of the battery module through the first switch S1, the inductor L, and the third switch S3 back to the negative terminal of the battery module. During this stage, the inductor L releases its stored energy, which is then superimposed on the voltage of the battery module, thereby achieving boost conversion.

[0035] S130, corresponding to the input voltage being within the second voltage range, the controller performs soft-switching step-down conversion by controlling the four-switch step-up / step-down circuit, and controls the second terminal of the four-switch step-up / step-down circuit to output the first voltage.

[0036] When the input voltage is in the second voltage range, the controller controls the four-switch buck-boost circuit 110 to step down the input voltage. That is, the first voltage is less than the minimum value of the second voltage range. In some examples, the second voltage range can be 1000V-1500V, and the first voltage is 750V.

[0037] Specifically, the controller can control the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4 to alternately turn on and off, so as to realize the soft-switching buck conversion of the four-switch buck-boost circuit 110. Among them, the second switch S2 and the third switch S3 are complementary synchronous rectifiers, and the first switch S1 and the fourth switch S4 are the main switches based on the timing of the four-sided inductor current. The four switches do not have a fixed continuous on or continuous off state.

[0038] The controller controls the four-switch buck-boost circuit 110 to perform soft-switching buck conversion, including charging mode, direct power transfer mode, reset mode and freewheeling mode timing, and the four modes are alternately turned on and off according to the timing pattern; by precisely controlling the time allocation of the four modes and the dead time of the switch drive, the inductor current forms a four-sided waveform containing the negative current range, which satisfies the zero-voltage switching (ZVS) realization conditions.

[0039] In the four modes of soft-switching buck converter, the inductor current waveforms at each stage are referenced. Figure 5 ;in, Figure 5 The horizontal axis represents time, and the vertical axis represents the inductor current flowing through inductor L. For example... Figure 5 As shown, during the charging mode in time period T1, the inductor current changes from... I ZVS The inductor current linearly rises to its peak value I1; in the direct power transfer mode during time period T2, the inductor current linearly rises from I1 to I2, but the rate of rise is slower than the rate of rise of the current during the charging mode; in the reset mode during time period T3, the inductor current linearly decreases from I2 to... I ZVSDuring the freewheeling mode in time period T4, the inductor current remains at... I ZVS constant.

[0040] Reference Figure 5 and Figure 6 In charging mode, the first switch S1 and the fourth switch S4 are turned on, while the second switch S2 and the third switch S3 are turned off. The current path is as follows: current flows from the positive terminal of the battery pack through the first switch S1, inductor L, and the fourth switch S4 back to the negative terminal of the input battery pack. The input voltage is applied across the inductor L, and the inductor current flows from the minimum negative current value. I ZVS The voltage rises linearly to its peak value I1. During this stage, the battery pack charges the inductor L, which stores magnetic field energy. The electrical device is powered by the output capacitor C. o powered by.

[0041] Reference Figure 5 and Figure 7 In the direct power transfer mode, the first switch S1 and the third switch S3 are turned on, while the second switch S2 and the fourth switch S4 are turned off. The current path is as follows: current flows from the positive terminal of the battery pack through the first switch S1, the inductor L, the third switch S3, and the electrical device back to the negative terminal of the input battery pack. The inductor voltage matches the input-output voltage difference, and the inductor current changes linearly from I1 to I2. During this stage, the inductor L directly transfers power to the electrical device and to the output capacitor C. o While charging, the inductor L continues to store magnetic field energy, achieving voltage reduction and energy transfer.

[0042] Reference Figure 5 and Figure 8 In reset mode, the second switch S2 and the third switch S3 are turned on, while the first switch S1 and the fourth switch S4 are turned off. The current path is as follows: current flows from inductor L through the second switch S2, the electrical equipment, and the third switch S3 back to inductor L. Inductor L releases magnetic field energy, and the inductor current linearly decreases from I2 to the minimum negative current value. I ZVS During this stage, inductor L continuously supplies power to the electrical equipment and output capacitor C. o Power supply to ensure continuous power transmission.

[0043] Reference Figure 5 and Figure 9 In freewheeling mode, the second switch S2 and the fourth switch S4 are turned on, while the first switch S1 and the third switch S3 are turned off. The current path is that the current flows from the inductor L through the second switch S2 and the fourth switch S4 back to the inductor L, forming a freewheeling loop. During this stage, the inductor current is maintained at... I ZVSThe current remains unchanged, providing the necessary negative current condition for the ZVS of the switching transistor in the next switching cycle. The electrical equipment is powered by the output capacitor C. o powered by.

[0044] After the above four modes are completed, the next switching cycle begins, and the above process is repeated. The time allocation of the four modes can be dynamically adjusted according to the input and output voltages and the load to ensure that the inductor current is always a four-sided waveform, which meets the ZVS implementation requirements.

[0045] Combination Figure 1 The four-switch buck-boost topology shown retains the complete four-switch buck-boost circuit 110 structure in the above switching state. By utilizing the four-mode timing modulation of the four-sided inductor current control strategy, the converter is equivalent to a buck four-switch converter with ZVS capability. It retains the core buck conversion function and achieves zero-voltage turn-on of all switches through the negative current range of the inductor current, eliminating the high switching losses caused by hard switching.

[0046] S140, corresponding to the input voltage being in the third voltage range, the controller performs a pass-through topology transformation by controlling the four-switch buck-boost circuit, and controls the second terminal of the four-switch buck-boost circuit to directly output the input voltage.

[0047] When the input voltage is within the third voltage range, the controller controls the four-switch buck-boost circuit 110 to directly output the input voltage. That is, the output voltage equals the input voltage. In some examples, the third voltage range can be 700V-1000V, and the output voltage can be 700V-1000V. For instance, when the input voltage is 800V, the voltage output from the second terminal of the four-switch buck-boost circuit 110 is also 800V; when the input voltage is 900V, the voltage output from the second terminal of the four-switch buck-boost circuit 110 is also 900V.

[0048] Specifically, such as Figure 10 As shown, the controller can continuously turn on the first switch S1 to directly electrically connect the positive terminal of the battery module to the inductor L, and continuously turn on the third switch S3 to directly electrically connect the inductor L to the positive terminal of the output voltage. Simultaneously, the controller also continuously turns off the second switch S2 to block the buck freewheeling path, and continuously turns off the fourth switch S4 to block the boost freewheeling path, thereby controlling the second terminal to directly output the input voltage.

[0049] Combination Figure 1The four-switch buck-boost topology shown, during the pass-through topology transformation, has the first switch S1 and the third switch S3 simultaneously turned on, while the second switch S2 and the fourth switch S4 are simultaneously turned off, directly connecting the input and output sides. The current path is as follows: current flows directly from the positive terminal of the battery pack through the first switch S1, inductor L, and the third switch S3 to the electrical device and back to the negative terminal of the battery pack. During this stage, inductor L is short-circuited, with no high-frequency switching action, serving only as an electrical path for power transmission.

[0050] It should be understood that the execution of S120-S140 in the embodiments of this application has no order and can be performed one at a time.

[0051] This application also provides an energy storage converter, which can be applied in an energy storage system to convert direct current (DC) to alternating current (AC). For example, during off-peak hours, the energy storage converter can absorb AC power from the grid and convert it into DC power to charge the battery modules. During peak hours, the energy storage converter can convert the DC power released by the battery modules into AC power to supply power to the loads in the grid. This achieves peak shaving and valley filling to ensure real-time balance between power supply and demand.

[0052] like Figure 11 As shown, the energy storage converter 200 includes a DC side 210, an inverter 220, an AC side 230, and as shown in the figure. Figure 1 The voltage converter 100 shown has a DC side terminal 210, an inverter 220, and an AC side terminal 230 connected in sequence. The voltage converter 100 can achieve the following during operation: Figure 2 The operating method is shown.

[0053] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed, can achieve the following: Figure 2 The operating method is shown.

[0054] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the descriptions of each implementation method in the above embodiments have different focuses. For any part not described in detail in a certain implementation method, please refer to the corresponding process in the aforementioned implementation methods, which will not be repeated here.

[0055] This application provides a voltage converter and its operating method, an energy storage converter, and a computer-readable storage medium. The voltage converter 100 obtains the input voltage from the first terminal of a four-switch buck-boost circuit 110 via a controller. When the input voltage is within a low-voltage first voltage range, the four-switch buck-boost circuit 110 can perform hard-switching boost conversion under the control of the controller, thereby significantly reducing control complexity and hardware cost, and making losses controllable. When the input voltage is within a high-voltage second voltage range, the four-switch buck-boost circuit 110 can perform soft-switching buck conversion under the control of the controller, avoiding the high losses and high voltage stress of high-voltage hard switching, thus optimizing the problem of large switching losses. When the input voltage is within a medium-voltage third voltage range, the four-switch buck-boost circuit 110 can perform direct conversion under the control of the controller, thereby eliminating switching losses and significantly improving energy transmission efficiency.

[0056] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A voltage converter, characterized by It includes a four-switch buck-boost circuit and a controller. The first terminal of the four-switch buck-boost circuit is used to connect to the battery pack, and the second terminal of the four-switch buck-boost circuit is used to connect to the electrical equipment. The controller is connected to the four-switch buck-boost circuit, and the controller is configured to: Obtain the input voltage at the first terminal; Corresponding to the input voltage in the first voltage range, the four-switch buck-boost circuit is controlled to perform hard-switching boost conversion, thereby controlling the second terminal to output the first voltage. Corresponding to the input voltage in the second voltage range, the four-switch buck-boost circuit is controlled to perform soft-switching buck conversion, thereby controlling the second terminal to output the first voltage. The first voltage is between the maximum value of the first voltage range and the minimum value of the second voltage range.

2. The voltage converter of claim 1, wherein, The controller is also configured to: Corresponding to the input voltage being in the third voltage range, the second terminal is controlled to directly output the input voltage; The first voltage range, the second voltage range, and the third voltage range are continuous, and the third voltage range is located between the first voltage range and the second voltage range.

3. Voltage converter according to claim 2, characterized in that The four-switch buck-boost circuit includes a first switch, a second switch, a third switch, a fourth switch, and an inductor; wherein, The first terminal of the first switching transistor is connected to the first terminal; The second terminal of the first switching transistor is connected to the first terminal of the second switching transistor and the first terminal of the inductor, respectively. The second terminal of the second switching transistor is grounded; The first end of the third switching transistor is connected to the second end; The second terminal of the third switch is connected to the first terminal of the fourth switch and the second terminal of the inductor, respectively. The second end of the fourth switch is connected to the second end of the second switch.

4. The voltage converter of claim 3, wherein, The controller is further configured to: control the first switch to remain on, control the second switch to remain off, and control the third and fourth switches to alternately turn on and off, corresponding to the input voltage in a first voltage range; The third switch and the fourth switch are not turned on at the same time.

5. The voltage transformer of claim 3, wherein The controller is also configured to control the first switch, the second switch, the third switch, and the fourth switch to alternately turn on and off in a second voltage range corresponding to the input voltage; in During the first time period, the first switch and the fourth switch are turned on, while the second switch and the third switch are turned off. During the second time period, the first switch and the third switch are turned on, while the second switch and the fourth switch are turned off. During the third time period, the second and third switches are turned on, while the first and fourth switches are turned off. During the fourth time period, the second and fourth switching transistors are turned on, while the first and third switching transistors are turned off. The first time period, the second time period, the third time period, and the fourth time period are repeated cyclically.

6. The voltage transformer of claim 3, wherein, The controller is also configured to: control the first switch and the third switch to be turned on, and the second switch and the fourth switch to be turned off, corresponding to the input voltage being in the third voltage range.

7. A method of operating a voltage converter, characterized by, The voltage converter includes a four-switch buck-boost circuit, and the operation method includes: Obtain the input voltage at the first terminal of the four-switch buck-boost circuit, the first terminal being used to connect to the battery assembly; Corresponding to the input voltage in the first voltage range, the four-switch buck-boost circuit is controlled to perform hard-switching boost conversion, and the second terminal of the four-switch buck-boost circuit is controlled to output the first voltage. The second terminal is used to connect to the electrical equipment. Corresponding to the input voltage in the second voltage range, the four-switch buck-boost circuit is controlled to perform soft-switching buck conversion, thereby controlling the second terminal to output the first voltage. The first voltage is between the maximum value of the first voltage range and the minimum value of the second voltage range.

8. The operation method of the voltage converter according to claim 7, characterized in that, The operation method further includes: Corresponding to the input voltage being in the third voltage range, the four-switch buck-boost circuit is controlled to perform a pass-through topology transformation, thereby controlling the second terminal to directly output the input voltage.

9. An energy storage converter, characterized in that, It includes a DC side, an AC side, an inverter, and a voltage converter as described in any one of claims 1-6, wherein the DC side, the voltage converter, the inverter, and the AC side are connected in sequence.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed, enable the operation method described in claim 7 or 8.

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