A power switching method, device and multi-power supply system

Abstract

The present invention discloses a power switching method, device and multi-power supply system. The method is applied to a multi-power supply system, wherein the multi-power supply system includes an AC power supply, a DC power supply and an energy storage power supply, and the method includes: obtaining a power switching instruction; wherein the power switching instruction includes a power switching direction; and according to the power switching direction, controlling the energy storage power supply to perform voltage transition during the power switching process. The present invention can realize flexible switching of power supplies, avoid large fluctuations in bus voltage in a short period of time during power switching, and ensure stable operation of the multi-power supply system.

Description

Technical Field

[0001] The present invention relates to the field of electronic power technology, and in particular to a power switching method, device and a multi-power supply system. Background Art

[0002] At present, multi-power supply systems (such as AC / DC hybrid power inverters) all involve power switching. When the DC power supply is switched to the AC power supply, the bus voltage suddenly decreases, causing the speed of the downstream motor to decrease significantly, which may cause the motor to shut down in severe cases; and when the AC power supply is switched to the DC power supply, the DC bus voltage suddenly increases, which is easy to generate a large impact current, causing damage to the bus capacitor. At the same time, other electronic components in the system will be affected by voltage and current shocks, which will also affect their service life. In summary, whether the DC power supply is switched to the AC power supply, or the AC power supply is switched to the DC power supply, it will cause the bus voltage to fluctuate to a large extent in a short period of time, affecting the stable operation of the system.

[0003] In view of the problem that during power switching of a multi-power supply system in the prior art, the DC bus voltage fluctuates greatly in a short period of time, affecting the stable operation of the system, no effective solution has been proposed so far. Summary of the invention

[0004] A power switching method is provided in an embodiment of the present invention to solve the problem in the prior art that during the power switching process of a multi-power supply system, the DC bus voltage fluctuates greatly in a short period of time, affecting the stable operation of the system.

[0005] In order to solve the above technical problems, the present invention provides a power switching method, which is applied to a multi-power supply system, wherein the multi-power supply system includes an AC power supply, a DC power supply, and an energy storage power supply. The method includes:

[0006] Obtaining a power switching instruction; wherein the power switching instruction includes a power switching direction;

[0007] According to the power switching direction, the energy storage power supply is controlled to perform voltage transition during the power switching process.

[0008] Furthermore, if the power switching direction is switching from an AC power source to a DC power source, controlling the energy storage power source to perform a voltage transition during the power switching process includes:

[0009] After obtaining the power switching instruction, controlling the energy storage power supply to be turned on and perform voltage transition;

[0010] After the voltage transition is completed, controlling the DC power supply to be turned on;

[0011] After a first preset time period, the energy storage power supply is controlled to be disconnected.

[0012] Further, controlling the energy storage power supply to be turned on and perform voltage transition includes:

[0013] Controlling the energy storage power supply to be turned on and controlling the supply voltage of the energy storage power supply to be a first preset voltage; wherein the first preset voltage is less than a preset DC bus voltage;

[0014] The supply voltage output by the energy storage power supply is controlled to gradually increase to a second preset voltage according to a preset step size; wherein the second preset voltage is greater than the preset DC bus voltage and less than the supply voltage of the DC power supply.

[0015] Furthermore, the multi-power supply system further includes a rectifier circuit. After controlling the energy storage power supply to be turned on and perform voltage transition, the method further includes:

[0016] After the second preset time period, the rectification control signal of the rectification circuit is turned off.

[0017] Furthermore, if the power switching direction is switching from a DC power supply to an AC power supply, controlling the energy storage power supply to perform a voltage transition during the power switching process includes:

[0018] After obtaining the power switching instruction, controlling the energy storage power supply to be turned on and controlling the supply voltage of the energy storage power supply to be a third preset voltage; wherein the third preset voltage is less than a preset DC bus voltage;

[0019] After a third preset time period, the DC power supply is controlled to be disconnected and the energy storage power supply is controlled to perform voltage transition;

[0020] After completing the fourth preset time period of voltage transition, the energy storage power supply is controlled to be disconnected.

[0021] Further, controlling the energy storage power supply to perform voltage transition includes:

[0022] Controlling the supply voltage of the energy storage power supply to gradually decrease to a fourth preset voltage according to a preset step length;

[0023] Among them, the fourth preset voltage is greater than the uncontrolled rectifier voltage value in the multi-power supply system, and the uncontrolled rectifier voltage is the effective voltage value output by the rectifier circuit in the multi-power supply system after the rectifier control signal of the rectifier circuit is turned off.

[0024] Furthermore, before obtaining the power switching instruction, the method further includes:

[0025] Detecting whether a fault occurs in the multi-power supply system;

[0026] If yes, then enter the fault handling procedure;

[0027] If not, a predetermined power supply is controlled to be turned on, and then a power switching instruction is triggered.

[0028] The present invention also provides a power switching device, which is applied to a multi-power supply system, wherein the multi-power supply system includes an AC power supply, a DC power supply, and an energy storage power supply. The device includes:

[0029] An instruction acquisition module, used to acquire a power switching instruction; wherein the power switching instruction includes a power switching direction;

[0030] The execution module is used to control the voltage transition of the energy storage power supply during the power switching process according to the power switching direction.

[0031] The present invention also provides a multi-power supply system, including an AC power supply, a DC power supply, an energy storage power supply, and the above-mentioned power supply switching device.

[0032] The present invention also provides a computer-readable storage medium on which a computer program is stored, and the program implements the power switching method when executed by a processor.

[0033] By applying the technical solution of the present invention, when power switching is performed, the voltage transition of the energy storage power supply during the power switching process is controlled according to the direction of the power switching, so as to reduce the DC bus voltage fluctuation during the power switching process, thereby realizing flexible power switching, avoiding large fluctuations in the DC bus voltage in a short period of time during the power switching process, and ensuring the stable operation of the multi-power supply system. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a circuit structure diagram of a multi-power supply system according to an embodiment of the present invention;

[0035] Figure 2 is a flow chart of a power switching method according to an embodiment of the present invention;

[0036] Figure 3 is a flow chart of a power switching method according to another embodiment of the present invention;

[0037] Figure 4 is a structural diagram of a power switching device according to an embodiment of the present invention;

[0038] Figure 5 is a structural diagram of a power switching device according to another embodiment of the present invention;

[0039] Figure 6 FIG. 4 is a structural block diagram of a multi-power supply system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0042] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0043] It should be understood that, although the terms first, second, third, etc. may be used to describe the preset durations in the embodiments of the present invention, these preset durations should not be limited to these terms. These terms are only used to distinguish different preset durations. For example, without departing from the scope of the embodiments of the present invention, the first preset duration may also be referred to as the third preset duration, and similarly, the third preset duration may also be referred to as the first preset duration.

[0044] As used herein, the words "if" and "if" may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0045] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0046] The optional embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0047] Example 1

[0048] This embodiment provides a power switching method, which is applied to a multi-power supply system. Figure 1 is a circuit structure diagram of a multi-power supply system according to an embodiment of the present invention, such as Figure 1 As shown, the multi-power supply system includes an AC power supply 2, a DC power supply 3, an energy storage power supply 4, and also includes a rectifier circuit 51 composed of IGBT1~IGBT6, and an inverter circuit 52 composed of IGBT7~IGBT12. Two DC busbars are connected between the rectifier circuit 51 and the inverter circuit 52. A plurality of bus capacitors C and a first resistor R and a second resistor R2 connected in series are bridged between the two DC busbars. A first switch K1 is provided between the AC power supply 2 and the rectifier circuit 51 for controlling the on and off of the AC power supply 2. The DC power supply 3 is connected to the above-mentioned DC busbar through the second switch K2, and the on and off of the DC power supply 3 is controlled by closing or opening the second switch K2. The energy storage power supply 4 is connected to the above-mentioned DC busbar through the third switch K3, and the on and off of the energy storage power supply 4 is controlled by closing or opening the third switch K3.

[0049] The multi-power supply system further includes a charging circuit 6, which is arranged between the AC power supply 2 and the DC bus, and is used to charge the bus capacitor C between the two DC buses to increase the DC bus voltage. One end of the inverter circuit 52 is connected to the rectifier circuit 51, and the other end is connected to the motor.

[0050] In the above-mentioned multi-power supply system, when the DC power supply 3 is switched to the AC power supply 2, the bus voltage suddenly decreases, causing the rear motor speed to decrease significantly, thereby causing the motor to shut down; and when the AC power supply 2 is switched to the DC power supply 3, the DC bus voltage suddenly increases, which is easy to generate a large impact current, causing damage to the bus capacitor C. At the same time, other electronic components in the system are also affected by voltage and current shocks, which will also affect their service life. In summary, whether the DC power supply 3 is switched to the AC power supply 2, or the AC power supply 2 is switched to the DC power supply 3, it will cause the bus voltage to fluctuate to a large extent in a short period of time, affecting the stable operation of the system.

[0051] In order to solve the above problem, this embodiment provides a power switching method. Figure 2 is a flow chart of a power switching method according to an embodiment of the present invention. Figure 2 As shown, the method includes:

[0052] S101, obtaining a power switching instruction; wherein the power switching instruction includes a power switching direction.

[0053] In specific implementation, the power switching direction includes switching from AC power to DC power, and switching from DC power to AC power. The above power switching instruction can come from the user's operation, or the power switching conditions can be pre-set. When the conditions are met, the power switching instruction is automatically generated.

[0054] S102, according to the power switching direction, controlling the energy storage power source to perform voltage transition during the power switching process.

[0055] In the two situations of switching from AC power to DC power and from DC power to AC power, the energy storage power supply is controlled to transition from low to high or from high to low voltage during the power switching process, so as to reduce the DC bus voltage fluctuation during the power switching process.

[0056] The power switching method of this embodiment controls the voltage transition of the energy storage power supply during the power switching process according to the direction of the power switching when performing power switching, so as to reduce the DC bus voltage fluctuation during the power switching process, and can realize flexible switching of power supplies, avoid large fluctuations in the DC bus voltage in a short period of time during the power switching process, and ensure the stable operation of the multi-power supply system.

[0057] Example 2

[0058] This embodiment provides another power switching method, in order to avoid the bus voltage from rising sharply in a short time when switching from AC power to DC power, if the power switching direction is switching from AC power to DC power, controlling the energy storage power supply to perform voltage transition during the power switching process, including: after obtaining the power switching instruction, controlling the energy storage power supply to be connected and perform voltage transition; after completing the voltage transition, controlling the DC power supply to be connected; after the first preset time, the power supply voltage of the DC power supply reaches a stable state, and controlling the energy storage power supply to be disconnected. Wherein, in order to ensure that the DC bus voltage rises smoothly, controlling the energy storage power supply to be connected and perform voltage transition, including: controlling the energy storage power supply to be connected and controlling the power supply voltage of the energy storage power supply to be a first preset voltage; wherein the first preset voltage is less than the preset DC bus voltage; controlling the power supply voltage output by the energy storage power supply to gradually rise to a second preset voltage according to a preset step length; wherein the second preset voltage is greater than the preset DC bus voltage and less than the power supply voltage of the DC power supply, the above operations, through the transition effect of the energy storage power supply, ensure that the power supply rises slowly when the power supply switches from AC power to DC power.

[0059] The above-mentioned multi-power supply system also includes a rectifier circuit. In order to avoid the DC bus voltage from feeding back to the power grid (i.e., AC power supply 2), after controlling the energy storage power supply to be turned on and performing voltage transition, the above-mentioned method also includes: after a second preset time period, turning off the rectification control signal of the rectifier circuit, so that the rectifier circuit is in an uncontrolled rectification state, and using the diode in the IGBT switch tube of the rectifier circuit for rectification.

[0060] When switching from AC power to DC power, the bus voltage increases significantly in a short period of time. On the contrary, when switching from DC power to AC power, the DC bus voltage will decrease significantly in a short period of time, which may cause the motor to shut down in severe cases. Therefore, in order to avoid a significant decrease in the DC bus voltage in a short period of time, if the power switching direction is switching from DC power to AC power, the energy storage power supply is controlled to perform voltage transition during the power switching process, including: after obtaining the power switching instruction, the energy storage power supply is controlled to be connected and the supply voltage of the energy storage power supply is controlled to be the third preset voltage; wherein the third preset voltage is less than the preset DC bus voltage, and the first step of voltage reduction is completed; after the third preset time, the DC bus voltage reaches stability, the DC power supply is controlled to be disconnected and the energy storage power supply is controlled to perform voltage transition, and the second step of voltage reduction is completed; after the fourth preset time of voltage transition is completed, the DC bus voltage has reached stability, and the energy storage power supply is controlled to be disconnected. In order to ensure a slow transition of the DC bus voltage, the energy storage power supply is controlled to perform a voltage transition, including: controlling the supply voltage of the energy storage power supply to gradually decrease to a fourth preset voltage according to a preset step size; wherein the fourth preset voltage is greater than the uncontrolled rectifier voltage value in the multi-power supply system, and the uncontrolled rectifier voltage is an effective voltage value output by the rectifier circuit after the rectifier control signal of the rectifier circuit in the multi-power supply system is turned off. The above operation, through the transition effect of the energy storage power supply, ensures that the power supply slowly decreases when the power supply switches from a DC power supply to an AC power supply.

[0061] Before obtaining the power switching instruction and executing the instruction, it is necessary to ensure that the multi-power supply system is in normal operation, that is, each power supply can supply power normally. Therefore, before obtaining the power switching instruction, the above method also includes: detecting whether the multi-power supply system has a fault; if so, entering the fault handling procedure; if not, controlling the predetermined power supply to be turned on, and then triggering the acquisition of the power switching instruction.

[0062] Figure 3 is a flow chart of a power switching method according to another embodiment of the present invention. Figure 3 As shown, the method includes:

[0063] S1, detect whether the multi-power supply system fails; if yes, execute step S2, if not, execute step S3.

[0064] S2, enter the fault handling procedure.

[0065] S3, controlling a predetermined power supply to be turned on, and then triggering step S4.

[0066] When detecting an AC power failure, detect whether the voltage fluctuation amplitude and frequency of the power grid are normal. If normal, it indicates that the AC power can operate normally. If abnormal, it indicates that a fault occurs, and enter the corresponding fault handling procedure. If normal, control the predetermined power supply to be connected. When detecting a DC power failure, determine whether there is an abnormality such as voltage overvoltage or undervoltage, and a large voltage fluctuation. If yes, enter the fault handling procedure. If not, control the predetermined power supply to be connected. For example, if it is predetermined that an AC power supply is used, control the AC power supply to be connected, that is, control the first switch K1 to be closed, the rectifier circuit to start, adjust the DC bus voltage to a preset DC bus voltage Vdc (for example, the DC bus voltage Vdc=600V), and the second switch K2 and the third switch K3 are disconnected. If it is predetermined that a DC power supply is used, control the second switch K2 to be closed, the first switch K1 to be closed, the control signal of the rectifier circuit to be closed, and the rectifier circuit is in an uncontrolled rectifier state. The third switch K3 is disconnected, and then step S4 is triggered.

[0067] S4, obtaining a power switching instruction.

[0068] S5, determining the power switching direction in the power switching instruction, if the power switching direction is from AC power to DC power, executing step S6, if the power switching direction is from DC power to AC power, executing step S10.

[0069] S6, control the energy storage power supply to be turned on and control the supply voltage of the energy storage power supply to be a first preset voltage; wherein the first preset voltage is less than the preset DC bus voltage; after a second preset time T2, turn off the control signal of the rectifier circuit to put it in an uncontrolled rectifier state.

[0070] S7, controlling the supply voltage output by the energy storage power supply to gradually increase to a second preset voltage according to a preset step size; wherein the second preset voltage is greater than the preset DC bus voltage Vdc, and less than the supply voltage Vdcpower of the DC power supply.

[0071] S8, controls the DC power supply to be turned on.

[0072] S9, after the first preset time T1, the energy storage power supply is controlled to be disconnected, the switching from the AC power supply to the DC power supply is completed, and then the process returns to step S4.

[0073] In specific implementation, after determining that the power switching direction is from AC power to DC power, the third switch K3 is controlled to close, the energy storage power supply is turned on, and the power supply voltage Vst = 0.99Vdc is output; after the second preset time T2, the rectification control is turned off, and the rectification circuit is in an uncontrolled rectification state to ensure that the DC bus voltage will not be fed back to the AC power grid and cause interference to the power grid. The energy storage power supply voltage Vst is controlled to slowly increase to equal to 0.99*DC power supply voltage Vdcpower (for example, DC power supply voltage Vdcpower = 750V), and then the second switch K2 is controlled to close to turn on the DC power supply. After the first preset time T1, the third switch K3 is controlled to be disconnected to enter the DC power supply mode.

[0074] S10, controlling the energy storage power supply to be turned on and controlling the supply voltage of the energy storage power supply to be a third preset voltage; wherein the third preset voltage is less than the preset DC bus voltage Vdc.

[0075] S11, after a third preset time T3, the second switch K2 is controlled to be turned off, so that the DC power supply is disconnected.

[0076] S12, controlling the supply voltage of the energy storage power supply to gradually decrease to a fourth preset voltage according to a preset step size; wherein the fourth preset voltage is greater than the uncontrolled rectifier voltage value Vdcdioe in the multi-power supply system, and the uncontrolled rectifier voltage Vdcdioe is the effective voltage value output by the rectifier circuit in the multi-power supply system after the rectifier control signal of the rectifier circuit is turned off.

[0077] S13, after completing the fourth preset time T4 of voltage transition, controlling the energy storage power supply to be disconnected, completing the switching from the DC power supply to the AC power supply, and then returning to step S4.

[0078] In specific implementation, after determining that the power switching direction is from DC power to AC power, first control the third K3 to close, and output the supply voltage Vst = 0.99 * preset DC bus voltage Vdc. After the third preset time T3, control the second switch K2 to disconnect, and at the same time control the supply voltage Vst of the energy storage power supply to slowly drop to the fourth preset voltage V4, wherein the fourth preset voltage V4 = 1.1 * uncontrolled rectifier voltage value Vdcdioe (for example, uncontrolled rectifier voltage value Vdcdioe = 537V). After the preset time T4, control the third switch K3 to disconnect and enter the AC power supply mode.

[0079] The power switching method of this embodiment realizes the flexible transition of bus voltage during AC / DC power switching, improves the reliability of the multi-power supply system, and at the same time reduces the impact of current shock on components during the power switching process, increases the service life of components, and reduces the manpower and material costs of frequent replacement of components.

[0080] Example 3

[0081] This embodiment provides a power switching device, Figure 4 is a structural diagram of a power switching device according to an embodiment of the present invention, such as Figure 4 As shown, the device includes: an instruction acquisition module 10, which is used to acquire a power switching instruction; wherein the power switching instruction includes a power switching direction.

[0082] In specific implementation, the power switching direction includes switching from AC power to DC power, and switching from DC power to AC power. The above power switching instruction can come from the user's operation, or the power switching conditions can be pre-set. When the conditions are met, the power switching instruction is automatically generated.

[0083] The execution module 20 is used to control the voltage transition of the energy storage power source during the power source switching process according to the power source switching direction.

[0084] In the two situations of switching from AC power to DC power and from DC power to AC power, the energy storage power supply is controlled to transition from low to high or from high to low voltage during the power switching process, so as to reduce the DC bus voltage fluctuation during the power switching process.

[0085] The power switching device of this embodiment, when performing power switching, executes the module 20 to control the voltage transition of the energy storage power supply during the power switching process according to the direction of the power switching, so as to reduce the DC bus voltage fluctuation during the power switching process, and can realize flexible switching of power supply, avoid large fluctuations in the DC bus voltage in a short period of time during the power switching process, and ensure the stable operation of the multi-power supply system.

[0086] Example 4

[0087] This embodiment provides another power switching device. Figure 5 FIG. 1 is a structural diagram of a power switching device according to another embodiment of the present invention. Figure 5As shown, in order to avoid a substantial increase in bus voltage in a short period of time when switching from AC power to DC power, the execution module 20 includes: a first execution unit 201, which is used to control the energy storage power supply to be connected and perform voltage transition when the power switching direction is switching from AC power to DC power; after completing the voltage transition, control the DC power supply to be connected; after a first preset time, the power supply voltage of the DC power supply reaches a stable state, and the energy storage power supply is controlled to be disconnected. Wherein, in order to ensure a smooth increase in the DC bus voltage, the energy storage power supply is controlled to be connected and the voltage transition is performed, including: controlling the energy storage power supply to be connected and controlling the power supply voltage of the energy storage power supply to be a first preset voltage; wherein the first preset voltage is less than the preset DC bus voltage; controlling the power supply voltage output by the energy storage power supply to gradually increase to a second preset voltage according to a preset step length; wherein the second preset voltage is greater than the preset DC bus voltage and less than the power supply voltage of the DC power supply.

[0088] The above-mentioned multi-power supply system also includes a rectifier circuit. In order to avoid the DC bus voltage from feeding back to the power grid, the first execution unit 201 is also used to: after controlling the energy storage power supply to be connected and performing voltage transition for a second preset time, turn off the rectification control signal of the rectifier circuit, so that the rectifier circuit is in an uncontrolled rectification state, and use the diode in the IGBT switch tube of the rectifier circuit for rectification.

[0089] When switching from AC power to DC power, the bus voltage increases significantly in a short time. On the contrary, when switching from DC power to AC power, the DC bus voltage will decrease significantly in a short time, which may cause the motor to stop in serious cases. Therefore, in order to avoid the DC bus voltage from decreasing significantly in a short time, the execution module 20 also includes: a second execution unit 202, which is used to control the energy storage power supply to be connected and control the supply voltage of the energy storage power supply to be a third preset voltage when the power switching direction is switching from DC power to AC power; wherein the third preset voltage is less than the preset DC bus voltage, and the first step of voltage reduction is completed; after the third preset time, the DC bus voltage reaches stability, the DC power supply is controlled to be disconnected and the energy storage power supply is controlled to perform voltage transition, and the second step of voltage reduction is completed; after the fourth preset time of the voltage transition is completed, the DC bus voltage has reached stability, and the energy storage power supply is controlled to be disconnected. In order to ensure a slow transition of the DC bus voltage, the energy storage power supply is controlled to perform a voltage transition, including: controlling the supply voltage of the energy storage power supply to gradually decrease to a fourth preset voltage according to a preset step size; wherein the fourth preset voltage is greater than an uncontrolled rectifier voltage value in the multi-power supply system, and the uncontrolled rectifier voltage is an effective voltage value output by the rectifier circuit in the multi-power supply system after the rectifier control signal of the rectifier circuit is turned off.

[0090] Before obtaining the power switching instruction and executing the instruction, it is necessary to ensure that the multi-power system is in normal operation, that is, each power supply can supply power normally. Therefore, the above-mentioned power switching device also includes: a detection module 30, which includes a detection unit 301, which is used to detect whether the multi-power supply system fails; a first trigger unit 302, which is used to trigger the entry of a fault handling program when a fault occurs in the multi-power supply system; a second trigger unit 303, which is used to control a predetermined power supply to be connected when no fault occurs in the multi-power supply system, and then trigger the acquisition of the power switching instruction.

[0091] Example 5

[0092] This embodiment provides a multi-power supply system. Figure 6 is a structural block diagram of a multi-power supply system according to an embodiment of the present invention. Figure 6 As shown, the multi-power supply system includes: an AC power supply 2, a DC power supply 3, an energy storage power supply 4, a frequency converter 5 composed of a rectifier circuit 51 and an inverter circuit 52, a motor, and also includes the power switching device 1 in the above embodiment.

[0093] like Figure 6 As shown, the power switching device 1 establishes communication connections with the AC power supply 2, the DC power supply 3, the energy storage power supply 4, and the inverter 5 to realize the above-mentioned power switching and fault detection functions. It is used to realize flexible switching of power supplies, avoid large fluctuations in bus voltage in a short period of time during power switching, and ensure stable operation of the multi-power supply system.

[0094] Example 6

[0095] This embodiment provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the power switching method in the above embodiment is implemented.

[0096] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0097] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0098] Finally, it should be noted that 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A power switching method, applied to a multi-power supply system, wherein the multi-power supply system includes an AC power supply, a DC power supply, and an energy storage power supply, characterized in that: The method comprises: Obtaining a power switching instruction; wherein the power switching instruction includes a power switching direction; According to the power switching direction, the voltage transition of the energy storage power supply during the power switching process is controlled; if the power switching direction is switching from an AC power supply to a DC power supply, the voltage transition of the energy storage power supply during the power switching process is controlled, including: after obtaining a power switching instruction, controlling the energy storage power supply to be turned on and controlling the supply voltage of the energy storage power supply to be a first preset voltage; wherein the first preset voltage is less than a preset DC bus voltage; controlling the supply voltage output by the energy storage power supply to gradually increase to a second preset voltage according to a preset step length; wherein the second preset voltage is greater than the preset DC bus voltage and less than the supply voltage of the DC power supply.

2. The method according to claim 1, characterized in that If the power switching direction is switching from an AC power source to a DC power source, controlling the energy storage power source to perform a voltage transition during the power switching process also includes: After the voltage transition is completed, controlling the DC power supply to be turned on; After a first preset time period, the energy storage power supply is controlled to be disconnected.

3. The method according to claim 2, characterized in that The multi-power supply system further includes a rectifier circuit. After controlling the energy storage power supply to be turned on and perform voltage transition, the method further includes: After the second preset time period, the rectification control signal of the rectification circuit is turned off.

4. The method according to claim 1, characterized in that If the power switching direction is switching from a DC power supply to an AC power supply, controlling the energy storage power supply to perform a voltage transition during the power switching process includes: After obtaining the power switching instruction, controlling the energy storage power supply to be turned on and controlling the supply voltage of the energy storage power supply to be a third preset voltage; wherein the third preset voltage is less than a preset DC bus voltage; After a third preset time period, the DC power supply is controlled to be disconnected and the energy storage power supply is controlled to perform voltage transition; After completing the fourth preset time period of voltage transition, the energy storage power supply is controlled to be disconnected.

5. The method according to claim 4, characterized in that Controlling the energy storage power supply to perform voltage transition includes: Controlling the supply voltage of the energy storage power supply to gradually decrease to a fourth preset voltage according to a preset step length; Among them, the fourth preset voltage is greater than the uncontrolled rectifier voltage value in the multi-power supply system, and the uncontrolled rectifier voltage is the effective voltage value output by the rectifier circuit in the multi-power supply system after the rectifier control signal of the rectifier circuit is turned off.

6. The method according to claim 1, characterized in that Before obtaining the power switching instruction, the method further includes: Detecting whether a fault occurs in the multi-power supply system; If yes, then enter the fault handling procedure; If not, a predetermined power supply is controlled to be turned on, and then a power switching instruction is triggered.

7. A power switching device, applied to a multi-power supply system, wherein the multi-power supply system includes an AC power supply, a DC power supply, and an energy storage power supply, characterized in that: The device comprises: An instruction acquisition module, used to acquire a power switching instruction; wherein the power switching instruction includes a power switching direction; An execution module is used to control the voltage transition of the energy storage power supply during the power switching process according to the power switching direction, so as to reduce the DC bus voltage fluctuation during the power switching process; if the power switching direction is switching from an AC power supply to a DC power supply, control the voltage transition of the energy storage power supply during the power switching process, including: after obtaining a power switching instruction, control the energy storage power supply to be turned on and control the supply voltage of the energy storage power supply to be a first preset voltage; wherein the first preset voltage is less than a preset DC bus voltage; control the supply voltage output by the energy storage power supply to gradually increase to a second preset voltage according to a preset step length; wherein the second preset voltage is greater than the preset DC bus voltage and less than the supply voltage of the DC power supply.

8. A multi-power supply system, including an AC power supply, a DC power supply, and an energy storage power supply, characterized in that: Also includes the power switching device as described in claim 7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

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