Direct-current bus voltage spike suppression method and device and light storage air conditioning system

Abstract

The invention provides a direct-current bus voltage spike suppression method and device and a light storage air conditioning system, and relates to the field of air conditioners. The method comprises the following steps: acquiring a bus voltage value and a voltage change slope on a direct-current bus under the condition that a peak exists in the voltage of the direct-current bus of the optical storage air conditioning system; and according to the bus voltage value and the voltage change slope, the charging current or the discharging current of an energy storage system in the light storage air conditioning system is controlled, so that the peak of the direct-current bus voltage is reduced. The peak of the direct-current bus voltage is absorbed by controlling the charge and discharge current of the energy storage system, so that on one hand, the problem of the bus peak caused by switching-in or switching-out of the photovoltaic equipment is solved, and the cost problem caused by selecting a relatively large bus capacitor is reduced; the problem of bus peak caused by shutdown of the compressor can be solved without additionally adding a discharge loop, and the overall cost of the system can also be reduced.

Description

Technical Field

[0001] The present disclosure relates to the field of air conditioning, and in particular to a method and device for suppressing a DC bus voltage spike, and a photovoltaic energy storage air conditioning system. Background Art

[0002] In the photovoltaic energy storage air conditioning system, when the photovoltaic equipment is switched on or off, or when the compressor is shut down, the bus voltage will spike. If the bus voltage spike is too large, it will have a certain impact on the photovoltaic energy storage air conditioning system.

[0003] In the related art, the voltage level of the bus voltage is increased to suppress the damage of voltage spikes to the photovoltaic storage air conditioning system. Alternatively, a discharge circuit is added to the DC bus to reduce the voltage spike when the compressor stops. The discharge circuit discharges the bus energy through a resistor to reduce the bus voltage, but the addition of the discharge circuit cannot solve the peak problem of photovoltaic equipment switching in and out when the photovoltaic storage air conditioning system is running. Summary of the invention

[0004] A technical problem to be solved by the present disclosure is to provide a method, device and photovoltaic air-conditioning system for suppressing DC bus voltage spikes, which can suppress DC bus voltage spikes without adding additional discharge circuits or increasing the bus withstand voltage to improve the system's peak tolerance.

[0005] According to one aspect of the present disclosure, a method for suppressing a DC bus voltage spike is proposed, comprising: when a DC bus voltage spike exists in a photovoltaic energy storage air conditioning system, obtaining a bus voltage value and a voltage change slope on the DC bus; and controlling a charging current or a discharging current of an energy storage system in the photovoltaic energy storage air conditioning system according to the bus voltage value and the voltage change slope, so as to reduce a DC bus voltage spike.

[0006] In some embodiments, controlling the charging current of the energy storage system in the photovoltaic air-conditioning system according to the bus voltage value and the voltage change slope includes: when the bus voltage value is greater than a voltage threshold at which there is no spike in the DC bus voltage, calculating the charging current increment of the energy storage system according to the voltage change slope; and controlling the charging current of the energy storage system according to the charging current increment.

[0007] In some embodiments, controlling the charging current of the energy storage system according to the charging current increment includes: increasing the charging current of the energy storage system when the charging current increment is a positive value; maintaining the charging current of the energy storage system when the charging current increment is zero; and reducing the charging current of the energy storage system when the charging current increment is a negative value.

[0008] In some embodiments, calculating the charging current increment of the energy storage system according to the voltage change slope includes: calculating a first tilt angle corresponding to the voltage change slope, the first tilt angle ranges from -90° to 90°; calculating a first ratio of the first tilt angle to the 90° angle; and obtaining the charging current increment according to the product of the first ratio and the maximum charging increment threshold.

[0009] In some embodiments, controlling the discharge current of the energy storage system in the photovoltaic air-conditioning system according to the bus voltage value and the voltage change slope includes: when the bus voltage value is less than a voltage threshold at which there is no spike in the DC bus voltage, calculating the discharge current increment of the energy storage system according to the voltage change slope; and controlling the discharge current of the energy storage system according to the discharge current increment.

[0010] In some embodiments, controlling the discharge current of the energy storage system according to the discharge current increment includes: increasing the discharge current of the energy storage system when the discharge current increment is a positive value; maintaining the discharge current of the energy storage system when the discharge current increment is zero; and reducing the discharge current of the energy storage system when the discharge current increment is a negative value.

[0011] In some embodiments, controlling the discharge current of the energy storage system according to the discharge current increment includes: calculating a second inclination angle corresponding to the voltage change slope, the second inclination angle ranges from -90° to 90°; calculating a second ratio of the second inclination angle to the -90° angle; and obtaining the discharge current increment according to the product of the second ratio and the maximum discharge increment threshold.

[0012] In some embodiments, the energy storage system includes a first energy storage device having a charge and discharge rate greater than a predetermined rate.

[0013] In some embodiments, the first energy storage device comprises a lithium titanate energy storage device.

[0014] In some embodiments, when the energy storage system further includes a second energy storage device having a charge and discharge rate less than or equal to a predetermined charge and discharge rate, if it is detected that the power grid is off-grid, the second energy storage device is scheduled to discharge; and if a spike in the DC bus voltage is detected, the first energy storage device is called to charge or discharge.

[0015] According to another aspect of the present disclosure, a DC bus voltage spike suppression device is also proposed, including: a processing module, configured to obtain the bus voltage value and the voltage change slope on the DC bus when there is a spike in the DC bus voltage of the photovoltaic energy storage air-conditioning system; and a control module, configured to control the charging current or discharging current of the energy storage system in the photovoltaic energy storage air-conditioning system according to the bus voltage value and the voltage change slope, so as to reduce the peak of the DC bus voltage.

[0016] According to another aspect of the present disclosure, a DC bus voltage spike suppression device is also proposed, including: a memory; and a processor coupled to the memory, the processor being configured to execute the DC bus voltage spike suppression method as described above based on instructions stored in the memory.

[0017] According to another aspect of the present disclosure, a solar-storage air-conditioning system is also proposed, comprising: the above-mentioned DC bus voltage peak suppression device.

[0018] According to another aspect of the present disclosure, a computer-readable storage medium is further provided, on which computer program instructions are stored, and when the instructions are executed by a processor, the above-mentioned DC bus voltage spike suppression method is implemented.

[0019] According to another aspect of the present disclosure, a computer program product is also proposed, including a computer program or instructions, and when the computer program or instructions are executed by a processor, the above-mentioned DC bus voltage spike suppression method is implemented.

[0020] In the disclosed embodiment, the peak of the DC bus voltage is absorbed by controlling the charging and discharging current of the energy storage system. On the one hand, the problem of bus spikes caused by the switching on or off of photovoltaic equipment is solved, and the cost problem caused by selecting a larger bus capacitor is reduced. On the other hand, since the problem of bus spikes caused by compressor shutdown can be solved without adding an additional discharge circuit, the overall cost of the system can also be reduced.

[0021] Other features and advantages of the present disclosure will become apparent from the following detailed description of exemplary embodiments of the present disclosure with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0023] The present disclosure may be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:

[0024] Figure 1 It is a flowchart diagram of some embodiments of the DC bus voltage spike suppression method disclosed in the present invention;

[0025] Figure 2 It is a structural schematic diagram of some embodiments of the solar energy storage air conditioning system disclosed in the present invention;

[0026] Figure 3 A schematic diagram of the change of the DC bus voltage amplitude disclosed in the present invention;

[0027] Figure 4 Schematic diagram of the flow chart of other embodiments of the DC bus voltage spike suppression method disclosed in the present invention;

[0028] Figure 5 Schematic diagram of the flow chart of other embodiments of the DC bus voltage spike suppression method disclosed in the present invention;

[0029] Figure 6 Schematic diagram of the flow chart of other embodiments of the DC bus voltage spike suppression method disclosed in the present invention;

[0030] Figure 7 It is a schematic diagram of the structure of some embodiments of the DC bus voltage spike suppression device disclosed in the present invention;

[0031] Figure 8 Schematic diagram of the structure of some other embodiments of the DC bus voltage spike suppression device disclosed in the present invention. DETAILED DESCRIPTION

[0032] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present disclosure unless otherwise specifically stated.

[0033] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0034] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0035] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0036] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0037] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0038] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0039] The present disclosure provides a DC bus voltage spike suppression solution, which does not require an additional discharge circuit, nor does it require additional bus voltage withstand to improve the system peak tolerance. Instead, the energy storage system is used to absorb the DC bus voltage spike of the photovoltaic storage air conditioning system, thereby reducing the selection of the bus voltage withstand. The solution of the present disclosure will be introduced below using a specific embodiment as an example.

[0040] Figure 1 The flowchart of some embodiments of the DC bus voltage spike suppression method disclosed in the present invention is shown in FIG. 1 , which is performed by a DC bus voltage spike suppression device, such as a control circuit. The embodiment includes steps S11-S12.

[0041] like Figure 2 As shown, the photovoltaic storage air conditioning system includes a photovoltaic device 21, an energy storage system 22, an air conditioning DC interface 23 and an air conditioning motor 24, and also includes a rectifier power module unit 25 and a control circuit 26. The photovoltaic device 21 can output DC power to the DC bus, and the energy storage system can output DC power to the DC bus or absorb DC power on the DC bus by energy storage. The AC power output by the power grid 27 is converted into DC power through the rectifier power module unit 25 and output to the DC bus.

[0042] In step S11, when there is a spike in the DC bus voltage of the solar-energy storage air-conditioning system, the bus voltage value and the voltage change slope on the DC bus are obtained.

[0043] For example, Figure 3 As shown in the figure, when the DC bus voltage fluctuates, if an upward fluctuation is detected, it means that a photovoltaic device is connected or the compressor is shut down, causing a positive spike in the DC bus. Or if a downward fluctuation is detected, it means that the photovoltaic device is cut off, causing a negative spike in the DC bus.

[0044] In other words, when there is no spike in the DC bus voltage, the voltage threshold is V1. If the DC bus voltage V2 is detected to be greater than V1, it means that there is a positive spike in the bus voltage. If the DC bus voltage V2 is detected to be less than V1, it means that there is a negative spike in the bus voltage. Those skilled in the art should understand that the voltage threshold can be a single value or a range of values.

[0045] In some embodiments, the voltage change slope is the ratio of the difference between the bus voltage value at the current moment and the bus voltage value at the previous moment to time. A positive voltage change slope indicates that the voltage is increasing, a negative voltage change slope indicates that the voltage is decreasing, and a zero voltage change slope indicates that the DC bus voltage has reached a maximum peak value.

[0046] In step S12, the charging current or discharging current of the energy storage system in the solar-storage air-conditioning system is controlled according to the bus voltage value and the voltage change slope to reduce the peak of the DC bus voltage.

[0047] The energy storage system may be a first energy storage device having a charge and discharge rate greater than a predetermined rate, such as a lithium titanate energy storage device. The rapid charge and discharge capability of the lithium titanate energy storage device may be used to reduce voltage spikes.

[0048] If the power level of the photovoltaic air conditioning system is relatively small, a second energy storage device with a small charge and discharge rate can also be used to absorb voltage spikes. For example, the second energy storage device is a lithium iron phosphate energy storage system, thereby reducing costs.

[0049] In this embodiment, the peak of the DC bus voltage is absorbed by controlling the charging and discharging current of the energy storage system. On the one hand, the problem of bus spikes caused by the switching on or off of photovoltaic equipment is solved, and the cost problem caused by selecting a larger bus capacitor is reduced. On the other hand, since the problem of bus spikes caused by compressor shutdown can be solved without adding an additional discharge circuit, the overall system cost can also be reduced.

[0050] In some embodiments, step S12 is implemented, for example, as follows Figure 4 , Figure 4 1 is a flow chart of some other embodiments of the DC bus voltage spike suppression method disclosed in the present invention, including step S1211 and step S1212.

[0051] In step S1211, when the bus voltage value is greater than a voltage threshold at which the DC bus voltage does not have a spike, the charging current increment of the energy storage system is calculated according to the voltage change slope.

[0052] The bus voltage value is greater than the voltage threshold at which the DC bus voltage does not have a spike, indicating that a DC bus voltage spike exists at this time, and the DC bus voltage spike is caused by the access of the photovoltaic device or the shutdown of the compressor. The energy storage system needs to be charged to absorb the DC bus voltage spike.

[0053] If the voltage change slope is greater than zero, the voltage value of the DC bus voltage at the current moment is greater than the voltage value at the previous moment, and the charging current of the energy storage system needs to be increased to suppress the peak. Therefore, the charging current increment is a positive value; if the voltage change slope is less than zero, the voltage value of the DC bus voltage at the current moment is less than the voltage value at the previous moment, and the charging current of the energy storage system can be reduced. Therefore, the charging current increment is a negative value.

[0054] In some embodiments, a first tilt angle corresponding to the voltage change slope is calculated, and the first tilt angle ranges from -90° to 90°; a first ratio of the first tilt angle to the 90° angle is calculated; and the charging current increment is obtained based on the product of the first ratio and the maximum charging increment threshold.

[0055] For example, if the voltage change slope is 1, the first tilt angle is 45°, if the voltage change slope is 1.732, the first tilt angle is 60°. If the voltage change slope is -1, the first tilt angle is -45°, if the voltage change slope is -1.732, the first tilt angle is -60°.

[0056] In some embodiments, the maximum charging increment threshold is a slope angle of 90° corresponding to an increment Imax1 of 100% of the energy storage charging capacity. The first inclination angle is compared with 90° to obtain a first ratio, for example, if the first inclination angle is 45°, the first ratio is 1 / 2. The calculated charging current increment is 1 / 2 Imax1.

[0057] In this step, the charging current increment of the energy storage system is calculated according to the slope of the DC bus voltage change, which is convenient for the subsequent control of the charging current. The slope change of the bus voltage can also be adjusted by adjusting the charging current. When the voltage change slope is zero, it means that the rise of the bus voltage is suppressed by the charging action of the energy storage system, and the charging current increment is kept at zero at this time; when the voltage change slope is greater than zero, it means that the bus voltage is still rising, and the charging current increment is positive at this time, that is, the charging current is increased; when the voltage change slope is negative, it means that the bus voltage is decreasing, and the charging current increment is negative at this time, that is, the charging current is reduced. By calculating the charging current increment of the energy storage system and continuously adjusting the charging capacity of the energy storage system, the charging current of the energy storage system can be smoothly controlled.

[0058] In step S1212, the charging current of the energy storage system is controlled according to the charging current increment.

[0059] In this embodiment, the bus voltage value can be used to determine whether the energy storage system needs to be charged. The voltage change slope can be used to calculate the charging current increment of the energy storage system, thereby facilitating the control of the charging current of the energy storage system. By adjusting the charging capacity of the energy storage system, the energy storage system can smoothly absorb the DC bus voltage spike, reducing the impact on the photovoltaic storage air conditioning system.

[0060] In some embodiments, when the charging current increment is a positive value, the charging current of the energy storage system is increased; when the charging current increment is zero, the charging current of the energy storage system is maintained; and when the charging current increment is a negative value, the charging current of the energy storage system is reduced.

[0061] For example, when the voltage change slope is positive, the charging current increment is positive. If the voltage change slope is large, it means that the voltage spike is growing rapidly. At this time, the charging current needs to be increased to achieve rapid absorption of the voltage spike. If the voltage change slope is small, it means that the voltage spike is not growing rapidly, and the charging current can be increased slowly. When the voltage change slope is zero, the charging current increment is zero. The bus voltage rise is suppressed by the charging action, thereby maintaining the charging current of the energy storage system. When the voltage change slope is negative, the charging current increment is negative. If the absolute value of the voltage change slope is large, it means that the voltage drop is large. At this time, the charging current can be quickly reduced. If the absolute value of the voltage change slope is small, it means that the voltage drop is relatively stable. At this time, the charging current can be slowly reduced, thereby achieving stable control of the charging current of the energy storage system.

[0062] In some embodiments, step S12 is implemented, for example, as follows Figure 5 , Figure 5 1 is a flow chart of other embodiments of the DC bus voltage spike suppression method disclosed in the present invention, including step S1221 and step S1222.

[0063] In step S1221, when the bus voltage value is less than a voltage threshold at which the DC bus voltage does not have a peak, the discharge current increment of the energy storage system is calculated according to the voltage change slope.

[0064] The bus voltage value is less than the voltage threshold at which the DC bus voltage has no spike, indicating that there is a DC bus voltage spike at this time, and the DC bus voltage spike is caused by the photovoltaic device being cut off. The energy storage system needs to discharge to absorb the DC bus voltage spike.

[0065] If the voltage change slope is greater than zero, the voltage value of the DC bus voltage at the current moment is greater than the voltage value at the previous moment, which can reduce the discharge current of the energy storage system. Therefore, the discharge current increment is a negative value. If the voltage change slope is less than zero, the voltage value of the DC bus voltage at the current moment is less than the voltage value at the previous moment. At this time, the discharge current of the energy storage system needs to be increased to suppress the peak. Therefore, the discharge current increment is a positive value.

[0066] In some embodiments, a second tilt angle corresponding to the voltage change slope is calculated, and the second tilt angle ranges from -90° to 90°; a second ratio of the second tilt angle to the -90° angle is calculated; and the discharge current increment is obtained based on the product of the second ratio and the maximum discharge increment threshold.

[0067] For example, if the voltage change slope is 1, the second tilt angle is 45°, if the voltage change slope is 1.732, the second tilt angle is 60°, if the voltage change slope is -1, the second tilt angle is -45°, if the voltage change slope is -1.732, the second tilt angle is -60°.

[0068] In some embodiments, the maximum discharge increment threshold is -90°, and the slope angle corresponds to 100% of the energy storage discharge capacity increment Imax2. The obtained second inclination angle is compared with -90° to obtain a second ratio. For example, if the second inclination angle is 45°, the second ratio is 1 / 2. The calculated discharge current increment is 1 / 2 Imax2.

[0069] The maximum discharge increment threshold and the maximum charge increment threshold may be the same or different.

[0070] In this step, the discharge current increment of the energy storage system is calculated according to the slope of the DC bus voltage change, which is convenient for the subsequent control of the discharge current. The slope change of the bus voltage can also be adjusted by adjusting the discharge current. When the voltage change slope is zero, it means that the peak of the bus voltage is suppressed by the discharge action of the energy storage system, and the discharge current increment is kept at zero; when the voltage change slope is negative, it means that the bus voltage is rapidly decreasing, and the discharge current increment is positive, that is, the discharge current is increasing; when the voltage change slope is greater than zero, it means that the bus voltage is rising, and the discharge current increment is negative, that is, the discharge current is reduced. By calculating the discharge current increment of the energy storage system and continuously adjusting the discharge capacity of the energy storage system, the charging current of the energy storage system can be smoothly controlled.

[0071] In step S1222, the discharge current of the energy storage system is controlled according to the discharge current increment.

[0072] In this embodiment, the bus voltage value can be used to determine whether the energy storage system needs to discharge. The discharge current increment of the energy storage system can be calculated by the voltage change slope, so as to facilitate the control of the discharge current of the energy storage system. By adjusting the discharge capacity of the energy storage system, the energy storage system can smoothly absorb the DC bus voltage spike and reduce the impact on the photovoltaic storage air conditioning system.

[0073] In some embodiments, when the discharge current increment is a positive value, the discharge current of the energy storage system is increased; when the discharge current increment is zero, the discharge current of the energy storage system is maintained; and when the discharge current increment is a negative value, the discharge current of the energy storage system is reduced.

[0074] For example, when the voltage change slope is negative, the discharge current increment is positive. If the absolute value of the voltage change slope is large, it means that the bus voltage drops quickly. At this time, the discharge current needs to be increased to reduce the voltage spike. If the absolute value of the voltage change slope is small, it means that the bus voltage does not drop quickly, and the discharge current can be increased slowly. When the voltage change slope is zero, the discharge current increment is zero, indicating that the bus voltage drop is suppressed by the discharge action, thereby maintaining the discharge current of the energy storage system. When the voltage change slope is positive, the discharge current increment is negative. If the voltage change slope is large, it means that the bus voltage rises quickly. At this time, the discharge current of the energy storage system can be quickly reduced; if the voltage change slope is small, it means that the bus voltage changes slowly. At this time, the discharge current can be slowly reduced, thereby achieving smooth control of the discharge current of the energy storage system.

[0075] The above solution will be introduced below by taking a specific embodiment as an example. Figure 6 As shown, Figure 6 1 is a flow chart of some other embodiments of the DC bus voltage spike suppression method disclosed in the present invention, including steps S61-S66.

[0076] In step S61, it is detected whether a peak occurs in the DC bus voltage. If not, step S62 is executed; if so, step S63 is executed.

[0077] In step S62, the energy storage system is controlled according to the established energy storage charging and discharging logic.

[0078] In step S63, the voltage change slope is calculated.

[0079] In step S64, the inclination angle corresponding to the voltage variation slope is calculated.

[0080] For example, using the formula , and get the tilt angle , where the voltage change rate is k.

[0081] In step S65, the charge and discharge current increment is calculated according to the inclination angle.

[0082] In step S66, the energy storage system is dispatched to adjust the charging and discharging current according to the charging and discharging current increments.

[0083] When the photovoltaic device is connected, the DC bus voltage will rise. When the compressor stops, the bus voltage is affected by the motor back electromotive force and the voltage also rises. When the photovoltaic device is cut off, the DC bus voltage drops. In this embodiment, the energy storage system is dispatched by continuously detecting the DC bus voltage amplitude and calculating the voltage drop or rise, so that the DC bus voltage spike can be suppressed.

[0084] In some embodiments of the present disclosure, the energy storage system includes a first energy storage device having a charge and discharge rate greater than a predetermined rate.

[0085] In conventional energy storage systems, considering the cost issue, by configuring energy storage devices with high cost performance but low charge and discharge rates, the normal charging and discharging requirements can be met. After the power grid loses power, the energy storage system can respond to power the system. In this embodiment, a high-rate energy storage device, for example, a 6C-rate energy storage device, is used to achieve the problem of rapid power response.

[0086] In some embodiments, the first energy storage device comprises a lithium titanate energy storage device, which can achieve rapid charge and discharge, thereby achieving spike suppression.

[0087] In some embodiments, the energy storage system also includes a second energy storage device with a charge and discharge rate less than or equal to a predetermined rate. The second energy storage device includes a lithium iron phosphate energy storage device. The charge and discharge rate of the lithium iron phosphate energy storage device can reach 0.5C, which can meet the normal charging and discharging requirements.

[0088] If it is detected that the power grid is off-grid, the second energy storage device is dispatched to discharge, such as scheduling the lithium iron phosphate energy storage device to discharge; if a spike in the DC bus voltage is detected, the first energy storage device is called to charge or discharge, such as calling the lithium titanate energy storage device to charge or discharge.

[0089] The energy storage system is configured with different forms of energy storage devices. After the power grid is powered off, the cost-effective lithium iron phosphate energy storage device can respond to power the system and solve the problem of off-grid function. In the case of a spike in the DC bus voltage, the bus spike can be quickly offset by scheduling the charging or discharging of the lithium titanate energy storage device.

[0090] If the power level in the solar-storage air-conditioning system is small, the bus voltage spike can also be suppressed by charging and discharging the lithium iron phosphate energy storage device.

[0091] Figure 7 Schematic diagram of the structure of some embodiments of the DC bus voltage spike suppression device disclosed in the present invention, the embodiment includes a processing module 710 and a control module 720.

[0092] The processing module 710 is configured to obtain the bus voltage value and voltage change slope on the DC bus when there is a spike in the DC bus voltage of the solar energy storage air conditioning system, for example, by executing Figure 1 Step S11 is shown.

[0093] The control module 720 is configured to control the charging current or discharging current of the energy storage system in the solar energy storage air conditioning system according to the bus voltage value and the voltage change slope, so as to reduce the peak of the DC bus voltage. For example, Figure 1Step S12 is shown.

[0094] In some embodiments, when the bus voltage value is greater than a voltage threshold at which the DC bus voltage does not have a spike, the charging current increment of the energy storage system is calculated according to the voltage change slope; and the charging current size of the energy storage system is controlled according to the charging current increment.

[0095] For example, a first tilt angle corresponding to the voltage change slope is calculated, the first tilt angle ranges from -90° to 90°; a first ratio of the first tilt angle to the 90° angle is calculated; and a charging current increment is obtained based on the product of the first ratio and the maximum charging increment threshold.

[0096] When the charging current increment is a positive value, the charging current of the energy storage system is increased; when the charging current increment is zero, the charging current of the energy storage system is maintained; and when the charging current increment is a negative value, the charging current of the energy storage system is reduced.

[0097] In other embodiments, when the bus voltage value is less than a voltage threshold at which the DC bus voltage does not have a spike, the discharge current increment of the energy storage system is calculated according to the voltage change slope; and the discharge current size of the energy storage system is controlled according to the discharge current increment.

[0098] For example, calculate the second tilt angle corresponding to the voltage change slope, the second tilt angle ranges from -90° to 90°; calculate the second ratio of the second tilt angle to the -90° angle; and obtain the discharge current increment based on the product of the second ratio and the maximum discharge increment threshold.

[0099] When the discharge current increment is a positive value, the discharge current of the energy storage system is increased; when the discharge current increment is zero, the discharge current of the energy storage system is maintained; and when the discharge current increment is a negative value, the discharge current of the energy storage system is reduced.

[0100] In the above embodiment, the peak of the DC bus voltage is absorbed by controlling the charging and discharging current of the energy storage system. On the one hand, the problem of bus spikes caused by the switching on or off of the photovoltaic equipment is solved, and the cost problem caused by selecting a larger bus capacitor is reduced. On the other hand, since the problem of bus spikes caused by compressor shutdown can be solved without adding an additional discharge circuit, the overall system cost can also be reduced.

[0101] In some embodiments, the energy storage system includes a first energy storage device with a charge and discharge rate greater than a predetermined rate, that is, the energy storage system includes an energy storage device with a high charge and discharge rate, such as a lithium titanate energy storage device.

[0102] In some embodiments, the energy storage system also includes a second energy storage device with a charge and discharge rate less than or equal to a predetermined charge and discharge rate, such as a lithium iron phosphate energy storage device. The control module 720 is also configured to schedule the second energy storage device to discharge if it is detected that the power grid is off-grid, such as scheduling the lithium iron phosphate energy storage device to discharge; and if a spike in the DC bus voltage is detected, call the first energy storage device to charge or discharge, such as calling the lithium titanate energy storage device to charge or discharge.

[0103] In the above embodiment, after the power grid is powered off, the cost-effective lithium iron phosphate energy storage device can respond to power the system and solve the problem of off-grid function. In the case of a spike in the DC bus voltage, the bus spike can be quickly offset by scheduling the charging or discharging of the lithium titanate energy storage device.

[0104] Figure 8 Schematic diagram of the structure of some other embodiments of the DC bus voltage spike suppression device disclosed in the present invention, the DC bus voltage spike suppression device 800 includes a memory 810 and a processor 820. The memory 810 may be a disk, a flash memory or any other non-volatile storage medium. The memory 810 is used to store the instructions in the above embodiments. The processor 820 is coupled to the memory 810 and may be implemented as one or more integrated circuits, such as a microprocessor or a microcontroller. The processor 820 is used to execute the instructions stored in the memory.

[0105] In some embodiments, the processor 820 is coupled to the memory 810 via a BUS 830. The DC bus voltage spike suppression device 800 can also be connected to an external storage device 850 via a storage interface 840 to call external data, and can also be connected to a network or another computer system (not shown) via a network interface 860, which will not be described in detail here.

[0106] In this embodiment, by storing data instructions in a memory and then processing the instructions through a processor, it is possible to suppress DC bus voltage spikes through charging and discharging of the energy storage system without adding an additional discharge circuit or increasing the bus voltage resistance to improve the system's peak tolerance.

[0107] In some other embodiments of the present disclosure, a photovoltaic storage air conditioning system is provided, the photovoltaic storage air conditioning system comprising the DC bus voltage spike suppression device in the above embodiment, the DC bus voltage spike suppression device is, for example, a control circuit or a controller, wherein the DC bus voltage spike suppression device has been described in detail in the above embodiment and will not be further described here. The photovoltaic storage air conditioning system can solve the bus voltage spike caused by the photovoltaic equipment when it is put into operation or removed, and can also solve the voltage spike brought to the bus when the compressor suddenly stops.

[0108] In other embodiments, a computer-readable storage medium stores computer program instructions, which implement the steps of the method in the above-mentioned embodiment when the instructions are executed by the processor. It should be understood by those skilled in the art that the embodiments of the present disclosure can be provided as methods, devices, or computer program products. Therefore, the present disclosure can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present disclosure can take the form of a computer program product implemented on one or more computer-usable non-transient storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0109] In some embodiments, a computer program product is protected, including a computer program or an instruction, which implements the above method when the computer program or instruction is executed by a processor. The computer program product includes a computer program carried on a computer-readable medium, and the computer program contains program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through a communication device, or installed from a storage device, or installed from a ROM. When the computer program is executed by the CPU, the above functions defined in the method of the embodiment of the present disclosure are executed.

[0110] The present disclosure is described with reference to flowcharts and / or block diagrams of methods, devices (systems) and computer program products according to embodiments of the present disclosure. It should be understood that each process and / or block in the flowchart and / or block diagram and the combination of processes and / or blocks in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0111] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0112] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0113] So far, the present disclosure has been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed here.

[0114] The method and apparatus of the present disclosure may be implemented in many ways. For example, the method and apparatus of the present disclosure may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above order of steps for the method is for illustration only, and the steps of the method of the present disclosure are not limited to the order specifically described above, unless otherwise specifically stated. In addition, in some embodiments, the present disclosure may also be implemented as a program recorded in a recording medium, which includes machine-readable instructions for implementing the method according to the present disclosure. Therefore, the present disclosure also covers a recording medium storing a program for executing the method according to the present disclosure.

[0115] Although some specific embodiments of the present disclosure have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A method for suppressing a DC bus voltage spike, comprising: When there is a spike in the DC bus voltage of the solar-storage air-conditioning system, the bus voltage value and voltage change slope on the DC bus are obtained; as well as According to the bus voltage value and the voltage change slope, the charging current or discharging current of the energy storage system in the photovoltaic energy storage air conditioning system is controlled to reduce the peak of the DC bus voltage.

2. The DC bus voltage spike suppression method according to claim 1, wherein: The controlling of the charging current of the energy storage system in the photovoltaic energy storage air conditioning system according to the bus voltage value and the voltage change slope comprises: When the bus voltage value is greater than a voltage threshold at which the DC bus voltage does not have a spike, calculating a charging current increment of the energy storage system according to the voltage change slope; and The charging current of the energy storage system is controlled according to the charging current increment.

3. The DC bus voltage spike suppression method according to claim 2, wherein: The controlling the charging current of the energy storage system according to the charging current increment comprises: When the charging current increment is a positive value, increasing the charging current of the energy storage system; When the charging current increment is zero, maintaining the charging current of the energy storage system; and When the charging current increment is a negative value, the charging current of the energy storage system is reduced.

4. The DC bus voltage spike suppression method according to claim 2, wherein: Calculating the charging current increment of the energy storage system according to the voltage change slope includes: Calculating a first tilt angle corresponding to the voltage change slope, wherein the first tilt angle ranges from -90° to 90°; Calculating a first ratio of the first tilt angle to an angle of 90°; and The charging current increment is obtained according to the product of the first ratio and the maximum charging increment threshold.

5. The DC bus voltage spike suppression method according to claim 1, wherein: The controlling of the discharge current of the energy storage system in the photovoltaic energy storage air conditioning system according to the bus voltage value and the voltage change slope comprises: When the bus voltage value is less than a voltage threshold value at which the DC bus voltage does not have a peak, calculating a discharge current increment of the energy storage system according to the voltage change slope; and The discharge current of the energy storage system is controlled according to the discharge current increment.

6. The DC bus voltage spike suppression method according to claim 5, wherein: The controlling the discharge current of the energy storage system according to the discharge current increment comprises: When the discharge current increment is a positive value, increasing the discharge current of the energy storage system; When the discharge current increment is zero, maintaining the discharge current of the energy storage system; and When the discharge current increment is a negative value, the discharge current of the energy storage system is reduced.

7. The DC bus voltage spike suppression method according to claim 5, wherein: The controlling the discharge current of the energy storage system according to the discharge current increment comprises: Calculating a second tilt angle corresponding to the voltage change slope, where the second tilt angle ranges from -90° to 90°; Calculating a second ratio of the second tilt angle to the -90° angle; and The discharge current increment is obtained according to the product of the second ratio and the maximum discharge increment threshold.

8. The method for suppressing a DC bus voltage spike according to any one of claims 1 to 7, wherein: The energy storage system includes a first energy storage device with a charge and discharge rate greater than a predetermined rate.

9. The method for suppressing a DC bus voltage spike according to claim 8, wherein: The first energy storage device includes a lithium titanate energy storage device.

10. The DC bus voltage spike suppression method according to claim 8, wherein: In the case where the energy storage system further includes a second energy storage device with a charge / discharge rate less than or equal to the predetermined charge / discharge rate, If it is detected that the power grid is disconnected, dispatching the second energy storage device to discharge; and If a peak is detected in the DC bus voltage, the first energy storage device is called to charge or discharge.

11. A DC bus voltage spike suppression device, comprising: The processing module is configured to obtain a bus voltage value and a voltage change slope on the DC bus when a DC bus voltage of the photovoltaic energy storage air conditioning system has a spike; as well as The control module is configured to control the charging current or discharging current of the energy storage system in the photovoltaic energy storage air conditioning system according to the bus voltage value and the voltage change slope, so as to reduce the peak of the DC bus voltage.

12. A DC bus voltage spike suppression device, comprising: Memory; as well as A processor coupled to the memory, wherein the processor is configured to execute the DC bus voltage spike suppression method according to any one of claims 1 to 10 based on instructions stored in the memory.

13. A solar energy storage air conditioning system, comprising: The DC bus voltage spike suppression device as claimed in claim 11 or 12.

14. A computer-readable storage medium having computer program instructions stored thereon, wherein when the instructions are executed by a processor, the DC bus voltage spike suppression method according to any one of claims 1 to 10 is implemented.

15. A computer program product, comprising a computer program or an instruction, wherein when the computer program or the instruction is executed by a processor, the method for suppressing a DC bus voltage spike according to any one of claims 1 to 10 is implemented.

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