Energy storage system control method, control device and energy storage system

Abstract

The present invention discloses a control method, a control device and an energy storage system, and relates to the field of energy storage technology. The energy storage system includes a distributed power supply, an energy storage device, a load, a control device and a switch device, and the control method includes: obtaining multiple first voltage detection signals output by multiple first voltage detection circuits, and confirming the output voltage of each distributed power supply according to the multiple first voltage detection signals; responding to the power demand of multiple loads, and confirming the power supply voltage of each load according to the power demand; confirming the load corresponding to the power supply voltage according to the output voltage of each distributed power supply, and outputting the corresponding switch conduction signal to the switch device, so that the output voltage of the distributed power supply supplies power to the corresponding load; wherein the voltage difference between the output voltage of the distributed power supply and the power supply voltage of the corresponding load is within a preset voltage difference range. The present invention aims to reduce the loss of electric energy in the energy storage system.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technology, and in particular to a control method, a control device and an energy storage system. Background Art

[0002] In an energy storage system with distributed power sources, the electric energy generated by the distributed power sources is usually output to the energy storage device, the load and the power grid respectively. However, distributed power sources are usually composed of solar photovoltaic panels, wind turbines, small hydropower stations, etc., and the voltage they output is often unstable. Taking solar photovoltaic panels as an example, the voltage they output is affected by many uncontrollable factors such as light and temperature. Whether it is an energy storage device, a load, or a power grid, a stable input voltage is required. Therefore, in the prior art, a voltage conversion circuit is often used to ensure the stability of the output voltage. However, this method will result in higher losses, especially when the difference between the output voltage and the supply voltage is large, and the effective use of electric energy cannot be ensured. Summary of the invention

[0003] The main purpose of the present invention is to provide a control method for an energy storage system, aiming to reduce the loss of electric energy in the energy storage system.

[0004] To achieve the above-mentioned purpose, the energy storage system includes a plurality of distributed power sources, an energy storage device, a plurality of loads, a control device and a plurality of switch devices, the output ends of the plurality of distributed power sources are electrically connected to the input ends of the plurality of switch devices in a one-to-one correspondence, the control device is electrically connected to the plurality of distributed power sources, the energy storage device, the plurality of loads and the controlled ends of the plurality of switch devices respectively, the output ends of the plurality of switch devices are electrically connected to the plurality of loads in a one-to-one correspondence and are connected to the energy storage device; each of the distributed power sources includes a first voltage detection circuit; the control method includes:

[0005] Acquire a plurality of first voltage detection signals output by a plurality of the first voltage detection circuits, and confirm the output voltage of each of the distributed power sources according to the plurality of first voltage detection signals;

[0006] Responding to power demands of the plurality of loads, and determining a supply voltage of each of the loads according to the power demands;

[0007] According to the output voltage of each of the distributed power sources, a load corresponding to the power supply voltage is determined, and a corresponding switch conduction signal is output to the switch device, so that the output voltage of the distributed power source supplies power to the corresponding load;

[0008] Wherein, a voltage difference between an output voltage of the distributed power supply and a supply voltage of a corresponding load is within a preset voltage difference range.

[0009] In one embodiment, the step of confirming a load corresponding to a power supply voltage according to the output voltage of each of the distributed power sources specifically includes:

[0010] The output voltage of each of the distributed power sources is divided into a plurality of levels, and the supply voltage of each of the loads is divided into a plurality of levels corresponding to the output voltage of each of the distributed power sources one by one;

[0011] Wherein, a difference between a maximum voltage value and a minimum voltage value between each level of the output voltage of each of the distributed power sources and a corresponding level of the power supply voltage of each of the loads is less than a preset difference.

[0012] In one embodiment, the energy storage system further includes a voltage conversion device, the output voltage of the distributed power supply includes a DC output voltage and an AC output voltage, the power supply voltage of each load includes a DC power supply voltage and an AC power supply voltage, and the step of confirming a load corresponding to the power supply voltage according to the output voltage of each distributed power supply specifically includes:

[0013] Determine a load corresponding to a power supply voltage type according to the type of output voltage of each of the distributed power sources;

[0014] When the type of the output voltage of each of the distributed power sources does not correspond to the type of the power supply voltage of each of the loads, the voltage conversion device is controlled to perform voltage conversion on the output voltage of the distributed power source and output it to the load or the energy storage device.

[0015] In one embodiment, a switch device is provided between the energy storage device and the load, and two ends of the switch device are electrically connected to the energy storage device and the load respectively. After the step of responding to the power demand of the plurality of loads and confirming the power supply voltage of each load according to the power demand, the method further includes:

[0016] When it is confirmed that the difference between the output voltage of the distributed power supply and the power supply voltage of the load is greater than a preset voltage difference range, confirm the output voltage of the energy storage device and output a corresponding switch conduction signal to the switch device so that the output voltage of the energy storage device supplies power to the corresponding load;

[0017] The voltage conversion device is controlled to perform voltage conversion on the output voltage of the distributed power source, and a corresponding switch conduction signal is output to the switch device, so that the output voltage of the distributed power source is used to charge the energy storage device.

[0018] In one embodiment, the energy storage device includes a second voltage detection circuit, and the control method further includes:

[0019] Acquire a second voltage detection signal output by a second voltage detection device, and confirm the storage power of the energy storage device according to the second voltage detection signal;

[0020] When the stored power of the energy storage device is higher than a first preset power, outputting a corresponding switch conduction signal to the switch device to upload the electric energy higher than the preset power to the power grid;

[0021] When the stored power of the energy storage device is lower than the second preset power, a corresponding switch-off signal is output to the switch device to stop the power output of the energy storage device.

[0022] In one embodiment, the energy storage device further includes a temperature detection circuit, a refrigeration device and a heating device, and the control method further includes:

[0023] Obtaining a temperature detection signal output by a temperature detection circuit, and confirming the ambient temperature of the energy storage device according to the temperature detection signal;

[0024] When the ambient temperature corresponding to the temperature detection signal is higher than a first preset temperature, controlling the refrigeration device to operate until the ambient temperature is lower than the first preset temperature;

[0025] When the ambient temperature corresponding to the temperature detection signal is lower than the second preset temperature, the heating device is controlled to operate until the ambient temperature is higher than the first preset temperature.

[0026] The present invention also proposes a control device, comprising: a memory, a processor, and a control program for an energy storage system stored in the memory and running on the processor, wherein the control program is configured to implement the steps of a control method for an energy storage system as described in any one of the above items.

[0027] The present invention also provides an energy storage system, which includes the control device as described above.

[0028] In one embodiment, the energy storage system includes a plurality of distributed power sources, an energy storage device, a plurality of loads, a plurality of switch devices, and a grid interface;

[0029] The output ends of the plurality of distributed power sources are electrically connected to the control device and the plurality of switch devices in a one-to-one correspondence, and the distributed power sources are used for energy conversion and outputting electric energy;

[0030] Two ends of the energy storage device are electrically connected to the switch device respectively, and the energy storage device is used to store electrical energy and output it when needed;

[0031] The controlled ends of the plurality of switch devices are electrically connected to the control device respectively, and the switch devices are used to switch on or off the paths connecting the two ends of the switch devices according to the switch control signals output by the control device;

[0032] The grid interface is electrically connected to the switch device, and the grid interface is used to access a grid.

[0033] The technical solution of the present invention obtains the output voltage of different distributed power sources by setting a voltage detection circuit, and obtains the power demand of different loads to confirm the power supply voltage corresponding to different loads, and compares whether the voltage difference between the output voltage of different distributed power sources and the power supply voltage of different loads is within the preset voltage difference range, thereby selecting the corresponding circuit between the distributed power source and the load. The control device controls the switch device of the corresponding circuit by outputting a switch conduction signal, so that the closing of the switch device conducts the path between the corresponding distributed power source and the load, thereby realizing the reasonable selection and setting of the circuit between the distributed power source and the load, and effectively reducing the problem of large energy loss of the distributed power source in the energy storage system due to voltage conversion when charging the energy storage device and supplying power to the load. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0035] Figure 1 A schematic flow chart of a control method for an energy storage system of the present invention;

[0036] Figure 2 A schematic diagram of a flow chart of an embodiment of a control method for an energy storage system of the present invention;

[0037] Figure 3 A schematic flow chart of another embodiment of a control method for an energy storage system of the present invention;

[0038] Figure 4 The figure is a flow chart of another embodiment of the control method of the energy storage system of the present invention.

[0039] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of 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] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0042] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0043] In an energy storage system with distributed power sources, the electric energy generated by the distributed power sources is usually output to the energy storage device, the load and the power grid respectively. However, distributed power sources are usually composed of solar photovoltaic panels, wind turbines, small hydropower stations, etc., and the voltage they output is often unstable. Taking solar photovoltaic panels as an example, the voltage they output is affected by many uncontrollable factors such as light and temperature. Whether it is an energy storage device, a load, or a power grid, a stable input voltage is required. Therefore, in the prior art, a voltage conversion circuit is often used to ensure the stability of the output voltage. However, this method will result in higher losses, especially when the difference between the output voltage and the supply voltage is large, and the effective use of electric energy cannot be ensured.

[0044] Therefore, reference Figure 1 The present invention provides a control method for an energy storage system, wherein the energy storage system comprises a plurality of distributed power sources, an energy storage device, a plurality of loads, a control device and a plurality of switch devices, wherein the output ends of the plurality of distributed power sources are electrically connected to the input ends of the plurality of switch devices in a one-to-one correspondence, the control device is electrically connected to the plurality of distributed power sources, the energy storage device, the plurality of loads and the controlled ends of the plurality of switch devices respectively, the output ends of the plurality of switch devices are electrically connected to the plurality of loads in a one-to-one correspondence and are connected to the energy storage device; each of the distributed power sources comprises a first voltage detection circuit; the control method comprises:

[0045] Step S100: acquiring a plurality of first voltage detection signals output by a plurality of the first voltage detection circuits, and confirming the output voltage of each of the distributed power sources according to the plurality of first voltage detection signals;

[0046] Step S200: responding to power demands of the plurality of loads and confirming the supply voltage of each load according to the power demands;

[0047] Step S300: according to the output voltage of each of the distributed power sources, confirm the load corresponding to the power supply voltage, and output the corresponding switch conduction signal to the switch device, so that the output voltage of the distributed power source supplies power to the corresponding load;

[0048] Wherein, a voltage difference between an output voltage of the distributed power supply and a supply voltage of a corresponding load is within a preset voltage difference range.

[0049] It is understandable that in the energy storage system, the electric energy output by the distributed power source will be supplied to the load first. When the load cannot fully digest the electric energy output by the distributed power source, the distributed power source will output the excess electric energy to the energy storage device to achieve power supply when the electric energy output by the distributed power source cannot meet the load demand, or when the distributed power source does not output electric energy. In addition, in the energy storage system, when both the energy storage device and the distributed power source cannot meet the power demand of the load, it is also possible to obtain electric energy from the grid by connecting to the grid, on the one hand to supply power to the load, and on the other hand to charge the energy storage device. The above series of adjustments are realized by the control device in the energy storage system, which realizes the input and output of electric energy by controlling the corresponding switching device, thereby ensuring the maximum utilization of electric energy.

[0050] In this embodiment, multiple distributed power sources can be implemented by any one or more of the power generation devices such as solar photovoltaic panels, wind turbines, etc. Among them, take solar photovoltaic panels as an example. Solar photovoltaic panels are mainly composed of multiple photovoltaic cells, which are usually silicon-based, and the silicon material can be single crystal silicon or polycrystalline silicon. When sunlight shines on the photovoltaic panel, the photons therein will excite the electrons in the semiconductor material, causing them to transition from the valence band to the conduction band, thereby generating free electrons. The electron-hole pairs generated near the PN junction will be separated by the built-in electric field, the electrons move to the N-type layer, and the holes move to the P-type layer. After the external circuit connects the two layers, the electrons can flow in the external circuit to form a current. This is the process of photovoltaic panels generating direct current. The power generation of solar photovoltaic panels is affected by many factors, such as solar radiation intensity, weather, temperature, installation angle, etc. This also leads to the output characteristics of solar photovoltaic panels being a nonlinear curve, and the relationship between its voltage and current changes with changes in factors such as light intensity and temperature. Among them, for a single photovoltaic cell, its open circuit voltage is usually between 0.4V and 0.7V. When multiple cells are connected in series to form a photovoltaic module or panel, its total voltage will be the sum of the voltages of each cell. For example, a common photovoltaic module may be composed of 36, 54, 60, 72 or 96 cells in series, and the corresponding open circuit voltage is about 18V, 27V, 30V, 36V or 48V respectively. Therefore, the expected output voltage of the solar photovoltaic panel can be set according to actual needs. Among them, in order to realize the detection of the output voltage of the distributed power supply, a voltage divider circuit, a differential amplifier circuit, a comparator circuit, etc. can be used. Among them, the voltage divider circuit divides the voltage by connecting two or more resistors in series, and proportionally reduces the voltage to be measured to the input range suitable for the measuring instrument (such as ADC). For example, two resistors are used in series, and the measurement point is located between the two resistors. The voltage drop calculated by Ohm's law is a part of the voltage to be measured. The differential amplifier circuit is suitable for the need to accurately measure the potential difference between two points in the circuit, especially when there is common-mode voltage interference, the differential amplifier circuit is very useful. The differential amplifier has two input terminals, which are respectively connected to the positive and negative terminals of the voltage to be measured, and can effectively suppress common-mode noise, amplify differential-mode signals, and improve measurement accuracy. The output voltage of the distributed circuit can be effectively detected by using a voltage detection circuit, so that the control device can perform corresponding control according to the first voltage detection signal.

[0051] In this embodiment, different loads have different power requirements in different time periods, such as lighting fixtures, variable frequency air conditioners, etc. The brightness of lighting fixtures can be adjusted by a dimmer, which means that in different time periods, such as noon, early morning and evening, the output brightness can be changed by adjusting the power supply voltage to achieve energy saving. Among them, the lighting fixture can control the on or off of the lamp through its self-set control program, or it can be triggered by the user or remotely controlled to turn the lamp on or off. The change of its brightness is controlled by its own system, and the power demand signal is output to the control device of the energy storage system. The control device confirms the power supply voltage required by the lighting fixture at this time through the power demand signal, so that the control device can perform the corresponding control action.

[0052] It is understandable that the voltage type output by the distributed power source may include both DC voltage and AC voltage. Among them, the output voltage of the distributed power source is also different. Therefore, the energy storage system also includes a voltage conversion device to convert the voltage output by the distributed power source so as to directly meet the power demand of the load. However, in the voltage conversion device, the greater the voltage difference between the input voltage and the output voltage, the greater the loss caused during the conversion process.

[0053] In this embodiment, the voltage values ​​output by different production equipment in the distributed power supply are obtained by obtaining the voltage detection circuit, and the power supply voltage required by the load is determined by obtaining the power demand of the load. The control device obtains the first voltage detection signal and the power supply voltage of the load to confirm the path between the corresponding production equipment and the corresponding load, so as to output the corresponding switch conduction signal, and then conduct the path between the corresponding production equipment and the load. Among them, the power supply equipment and the load can be realized by using a gating circuit. For example, there are production equipment A, production equipment B, and production equipment C in the distributed power supply, and the voltage value corresponding to the voltage detection signal obtained by the output voltage detection end of the production equipment A, production equipment B, and production equipment C at a certain moment is 10V, 32V, and 48V, and the power supply voltage required by the load at this time is 12V, then the 10V production equipment A is preferentially selected, and it is powered by the voltage conversion device. Because at this time, the voltage difference between the output voltage of the production equipment A and the power supply voltage required by the load is the smallest, which makes the loss caused by the voltage conversion device during voltage conversion smaller than that of the production equipment B and the production equipment C, thereby avoiding energy waste. It is understandable that the charging voltage of the energy storage device has greater flexibility than directly supplying power to the load. Therefore, the energy storage device B and the energy storage device C can supply power to other loads with corresponding power supply voltages, or charge the energy storage device. Similarly, in the energy storage system, the energy storage device can also be charged by selecting the corresponding energy storage device. Further, take the energy storage device as a solar photovoltaic panel as an example. By setting solar photovoltaic panel battery groups in different parallel connections, different solar photovoltaic panel battery groups can output different output voltage levels under the same lighting conditions. For example, under certain specific conditions, the output voltage of the first solar photovoltaic panel battery group is 18V; the output voltage of the second solar photovoltaic panel battery group is 27V; and the output voltage of the third solar photovoltaic panel battery group is 36V. If the power supply voltage of a load is 20V, the first solar photovoltaic panel battery group can be used for power supply first, and the output voltage of 18V can be converted to 20V for power supply through the voltage conversion device. When the external lighting conditions change, the output voltage of the first solar photovoltaic panel battery group becomes 12V, and the output voltage of the second solar photovoltaic panel battery group is 19V. At this time, the control device can detect the first voltage signal and output a corresponding switch conduction signal to the switch device, so that the output voltage of the second solar photovoltaic panel supplies power to the load, so as to minimize the difference between the output voltage of the distributed power source and the power supply voltage of the load, thereby reducing excessive loss of electric energy during voltage conversion. The range of the preset voltage difference can be reasonably set according to the type of distributed power source and the type of load.

[0054] In this embodiment, the output voltage of different distributed power sources is obtained by setting a voltage detection circuit, and the power demand of different loads is obtained to confirm the power supply voltage corresponding to different loads, and the voltage difference between the output voltage of different distributed power sources and the power supply voltage of different loads is compared to see whether it is within the preset voltage difference range, and then the corresponding circuit between the distributed power source and the load is selected. The control device controls the switch device of the corresponding circuit by outputting a switch conduction signal, so that the closing of the switch device conducts the path between the corresponding distributed power source and the load, thereby realizing the reasonable selection and setting of the circuit between the distributed power source and the load, and effectively reducing the problem of large power loss of the distributed power source due to voltage conversion.

[0055] refer to Figure 2 In one embodiment of the present invention, the step of confirming the load corresponding to the power supply voltage according to the output voltage of each of the distributed power sources specifically includes:

[0056] Step S310: dividing the output voltage of each of the distributed power sources into a plurality of levels, and dividing the supply voltage of each of the loads into a plurality of levels corresponding to the output voltage of each of the distributed power sources one by one;

[0057] Wherein, a difference between a maximum voltage value and a minimum voltage value between each level of the output voltage of each of the distributed power sources and a corresponding level of the power supply voltage of each of the loads is less than a preset difference.

[0058] It should be understood that in the energy storage system, the distributed power supply usually includes a variety of different power generation equipment, and the number and output voltage of different power generation equipment are also different; the load also usually includes a variety of different power consumption equipment, and the corresponding power supply voltage of different power consumption equipment is also different. Among them, the hierarchical division setting is performed for the power generation equipment with different output voltages in the distributed power supply, for example, the distributed power supply with an output voltage of 0 to 10V is divided into the first level, the distributed power supply with an output voltage of 10V to 20V is divided into the second level, and the distributed power supply with an output voltage of 20V to 30V is divided into the third level, etc. The corresponding hierarchical division setting is performed for the power consumption equipment with different power supply voltages in the load, for example, the load with a power supply voltage of 0 to 10V is divided into the first level, the load with a power supply voltage of 10V to 20V is divided into the second level, and the load with a power supply voltage of 20V to 30V is divided into the third level, etc. It can be understood that, for the distributed power supply and the load in the corresponding level, the voltage difference between the output voltage of the distributed power supply and the supply voltage of the load is always controlled within the preset difference range, that is, the voltage difference is always controlled within 10V. This hierarchical setting effectively avoids the voltage difference between the output voltage of the distributed power supply and the supply voltage of the load being too large, resulting in excessive loss of electric energy during the voltage conversion process. Among them, the division of levels and the setting of the preset difference can be set according to actual conditions, and the division of levels can also be unevenly divided, for example, the first level is 0 to 10V, the second level is 10V to 15V, etc.

[0059] Furthermore, the energy storage system further includes a voltage conversion device, the output voltage of the distributed power supply includes a DC output voltage and an AC output voltage, the power supply voltage of each load includes a DC power supply voltage and an AC power supply voltage, and the step of confirming the load corresponding to the power supply voltage according to the output voltage of each distributed power supply specifically includes:

[0060] Step S320: determining a load corresponding to a power supply voltage type according to the type of output voltage of each of the distributed power sources;

[0061] Step S330: When the type of the output voltage of each of the distributed power sources does not correspond to the type of the power supply voltage of each of the loads, control the voltage conversion device to perform voltage conversion on the output voltage of the distributed power source and output it to the load or the energy storage device.

[0062] It is understandable that the output voltage of a distributed power source usually includes a DC voltage and an AC voltage, and the supply voltage of the load also includes a DC voltage and an AC voltage. Therefore, in the energy storage system, the voltage conversion device usually includes a rectifier circuit, an inverter circuit, a boost circuit, a buck circuit, etc., so as to achieve the matching between the output voltage of the distributed power source and the supply voltage of the load. It should be understood that the boost circuit converts the input lower DC voltage into a higher DC voltage, and its loss mainly comes from switching loss, conduction loss, diode loss and inductor loss; the buck circuit converts the input higher DC voltage into a lower DC voltage, and its loss mainly comes from switching loss, conduction loss, inductor loss and output capacitor loss; the inverter circuit converts DC power into AC power, and its loss mainly comes from switching loss, conduction loss, filter loss and harmonic loss; the rectifier circuit converts AC power into DC power, and its loss mainly comes from diode loss, filter loss and harmonic loss. Further, the inverter circuit is generally considered to have the largest loss. Specifically, the inverter circuit usually requires a higher switching frequency to generate a smooth sine wave, which results in higher switching losses. In addition, the waveform output by the inverter usually contains more harmonic components, and these harmonic currents will generate additional losses when passing through the load. In addition, the inverter output needs to pass through a filter to improve the waveform quality, and the components in the filter will also generate losses. Furthermore, the design of the inverter is usually more complex than the boost or buck circuit, involving more components, each of which may introduce losses. Therefore, the boost circuit and the buck circuit mainly involve the conversion of DC to DC, usually operate at a lower frequency, and the switching loss is relatively small. Although the rectifier circuit also involves the conversion of AC to DC, since it usually only requires simple diode rectification, the loss is smaller than that of the inverter circuit. The control device confirms the type of output voltage of the distributed power supply and thus confirms the load corresponding to the power supply voltage. For example, if the output voltage of the distributed power supply is AC voltage, a load corresponding to the power supply voltage of AC voltage is selected to avoid the loss caused by the operation of the rectifier circuit; if the output voltage of the distributed power supply is DC voltage, a load corresponding to the power supply voltage of DC voltage is selected to avoid the loss caused by the operation of the inverter circuit. Among them, it is necessary to consider whether the output voltage of the corresponding type of distributed power supply and the supply voltage of the load are at the same level, and whether the voltage difference is greater than the preset difference, so as to confirm the relationship between the loss caused by the large-scale buck-boost of the corresponding type and the loss caused by the small-scale inverter rectification of different types, so as to further confirm the voltage conversion method. Furthermore, in the energy storage system, there is a situation where the output voltage of some distributed power supplies does not correspond to the type of the output voltage of the load. At this time, the control device is required to control the voltage conversion device to realize the conversion of the output voltage of the distributed power supply and output it to the load, so as to reduce the loss caused by the distributed power supply to the load under the premise of ensuring diversified power supply.

[0063] It is understandable that the essence of the energy storage device is a device for storing electrical energy, and what is stored inside it is DC electrical energy. Therefore, the charging voltage of the energy storage device must be charged with a DC voltage. When the output voltage of the distributed power supply has two output voltages, DC voltage and AC voltage, the DC output voltage is preferably selected to charge the energy storage device to avoid the additional loss caused by the AC voltage during the rectification process.

[0064] In one embodiment of the present invention, a switch device is provided between the energy storage device and the load, and two ends of the switch device are electrically connected to the energy storage device and the load respectively. After the step of responding to the power demand of the plurality of loads and confirming the power supply voltage of each load according to the power demand, the method further includes:

[0065] When it is confirmed that the difference between the output voltage of the distributed power supply and the power supply voltage of the load is greater than a preset voltage difference range, confirm the output voltage of the energy storage device and output a corresponding switch conduction signal to the switch device so that the output voltage of the energy storage device supplies power to the corresponding load;

[0066] The voltage conversion device is controlled to perform voltage conversion on the output voltage of the distributed power source, and a corresponding switch conduction signal is output to the switch device, so that the output voltage of the distributed power source is used to charge the energy storage device.

[0067] In this embodiment, when the distributed power supply may not be able to output a power supply voltage that meets any load under a specific environment, the control device will output a switch conduction signal to the switch device to make the path between the energy storage device and the load conductive. Among them, a voltage conversion circuit may also be provided between the energy storage device and the load to achieve the power supply requirements of different loads. In addition, a multi-level output voltage may be provided for the energy storage device to avoid the problem of excessive loss during the voltage conversion process caused by excessive pressure difference between the output voltage and the power supply voltage. Specifically, take the distributed power supply as a solar photovoltaic panel or a wind turbine as an example. Solar photovoltaic panels can only generate electricity when there is light shining on the photovoltaic panel. Therefore, solar photovoltaic panels can only output voltage when the sun shines. Wind turbines need to drive the motor to work through the mechanical energy of the blades when there is wind in the corresponding direction, thereby outputting voltage. When there is no wind in the corresponding direction, the wind turbine will not be able to output voltage. Therefore, under such conditions, the power supply voltage required by the load needs to be supplied by the energy storage device to meet the power supply voltage required for the load to work.

[0068] It is understandable that the voltage output by the distributed power supply under certain conditions is in an unstable state. Therefore, the distributed power supply at this time cannot provide a stable power supply for the load. However, the charging voltage of the energy storage device is a more flexible range. Although the voltage output by the distributed power supply is unstable, the energy storage device can still be intermittently charged by the voltage conversion device. In addition, because of the wide charging range of the energy storage device, the output voltage of the distributed power supply can be effectively obtained. Therefore, when the output voltage of the distributed power supply does not meet the power supply voltage of the load, the control device can be used to control the switch device to achieve control of the path, so that the distributed power supply can power the energy storage device while the energy storage device is powering the load.

[0069] refer to Figure 3 In one embodiment of the present invention, the energy storage device includes a second voltage detection circuit, and the control method further includes:

[0070] Step S400: obtaining a second voltage detection signal output by a second voltage detection device, and confirming the storage power of the energy storage device according to the second voltage detection signal;

[0071] Step S500: when the stored power of the energy storage device is higher than a first preset power, outputting a corresponding switch conduction signal to the switch device to upload the electric energy higher than the preset power to the power grid;

[0072] Step S600: When the stored power of the energy storage device is lower than a second preset power, a corresponding switch-off signal is output to the switch device to stop the power output of the energy storage device.

[0073] In this embodiment, the second voltage detection circuit is used to detect the remaining power of the energy storage device, and outputs a second voltage detection signal to the control device, so that the control device confirms the current power of the energy storage device according to the second voltage detection signal. It is understandable that the electric energy output by the distributed power supply is not uniform. Therefore, the electric energy output by the distributed power supply in a certain period of time may not only meet the power supply of all loads, but also realize the continuous charging of the energy storage device. However, in the energy storage device, the electric energy that can be stored is limited. Therefore, the corresponding first preset power can be set. The first preset power can be set according to the actual situation of the distributed power supply, the energy storage device and the load. For example, the first preset power is 80% of the energy storage device, that is, the part of the energy storage device that is higher than 80% of the power will be controlled by the control device to control the switch device, so that the electric energy in the energy storage device is uploaded to the power grid, thereby avoiding the waste of electric energy generated by the distributed power supply. Further, a second preset power is also set in the control device. The second preset power is the protection power of the energy storage device. It is understandable that in order to ensure the service life of the energy storage device, it is usually necessary to ensure that the minimum power of the energy storage device is not lower than the protection power to avoid deep discharge of the energy storage device. Among them, deep discharge will damage the structure of the battery, causing the battery capacity to decay faster. Overcharging will also have an adverse effect on the battery, especially when it is in a fully charged state for a long time, which may cause an increase in internal pressure of the battery, decomposition of the electrolyte, and changes in the chemical composition of the battery, thereby affecting the battery life. Therefore, the setting of the first preset power and the second preset power can not only avoid the waste of electric energy, but also ensure the service life of the energy storage device.

[0074] refer to Figure 4 In one embodiment of the present invention, the energy storage device further includes a temperature detection circuit, a refrigeration device and a heating device, and the control method further includes:

[0075] Step S700: obtaining a temperature detection signal output by a temperature detection circuit, and confirming the ambient temperature of the energy storage device according to the temperature detection signal;

[0076] Step S800: When the ambient temperature corresponding to the temperature detection signal is higher than a first preset temperature, controlling the refrigeration device to operate until the ambient temperature is lower than the first preset temperature;

[0077] Step S900: When the ambient temperature corresponding to the temperature detection signal is lower than the second preset temperature, the heating device is controlled to operate until the ambient temperature is higher than the first preset temperature.

[0078] It is important to understand that the rate of chemical reactions occurring inside the energy storage device is greatly affected by temperature. At different temperatures, changes in reaction rates can result in different battery performance. Under high temperature conditions, the chemical reaction rate accelerates, which may lead to an increase in side reactions inside the energy storage device, thereby accelerating the aging and capacity decay of the energy storage device. Under low temperature conditions, the chemical reaction rate slows down, the charge and discharge efficiency of the energy storage device decreases, and the energy storage device may not be able to provide sufficient power output. Changes in temperature will also affect the internal impedance of the energy storage device, thereby affecting the charge and discharge efficiency of the energy storage device. Under high temperature conditions, the internal impedance of the energy storage device may increase, resulting in more heat generated during the charge and discharge process, further exacerbating the temperature rise of the energy storage device. Under low temperature conditions, the internal impedance of the energy storage device increases, especially under low temperature conditions, the viscosity of the electrolyte increases, the migration speed of lithium ions slows down, and the charge and discharge efficiency of the energy storage device decreases. Therefore, the energy storage device needs to operate within a suitable temperature range to ensure its performance, life and safety.

[0079] In this embodiment, the temperature detection circuit can be implemented by a detection circuit based on a thermistor, such as a resistor voltage divider circuit based on an NTC resistor or an NTC probe, or a resistor voltage divider circuit based on a PTC resistor or a PTC probe. Optionally, the temperature detection circuit can also be implemented by a temperature sensor, such as an infrared temperature sensor, a thermocouple temperature sensor, etc. Among them, there can be multiple temperature detection circuits, and multiple temperature detection circuits can be arranged at different positions in the energy storage device. The control device can determine multiple temperature values ​​according to multiple temperature detection signals, and calculate the actual ambient temperature through a preset temperature algorithm, such as an average value, a weighted calculation, etc., so as to improve the accuracy of the detection of the ambient temperature of the drawer. Further, the control device can confirm the current ambient temperature of the energy storage device through the temperature detection signal, so as to accurately control the temperature adjustment device so that the ambient temperature of the energy storage device is regulated. Specifically, when the temperature value corresponding to the temperature detection signal is higher than the first preset temperature value, the control device will confirm that the current temperature of the energy storage device is high, so as to control the refrigeration device to work, so as to reduce the ambient temperature of the energy storage device. When the temperature value corresponding to the temperature detection signal is lower than the second preset temperature value, the control device will confirm that the current temperature of the energy storage device is low, thereby controlling the heating device to work, so as to increase the ambient temperature of the energy storage device. Among them, the first preset temperature and the second preset temperature can be set according to the type of energy storage device. By controlling the operation of the temperature adjustment device by the control device, it is effectively ensured that the ambient temperature of the energy storage device is in a relatively stable state. Among them, the temperature adjustment device is also a load. Therefore, the temperature adjustment device can be powered by a distributed power supply.

[0080] The present invention also proposes a control device, the control device comprising: a memory, a processor, and a control program for an energy storage system stored in the memory and running on the processor, the control program being configured to implement the steps of the control method for the energy storage system as described in any one of the above. It is worth noting that since the control device of the present invention is based on the above-mentioned control method for the energy storage system, the embodiments of the control device of the present invention include all technical solutions of all embodiments of the above-mentioned control method for the energy storage system, and the technical effects achieved are also exactly the same, which will not be repeated here.

[0081] The present invention also proposes an energy storage system, which includes the control device as described above. It is worth noting that since the energy storage system of the present invention is based on the control device described above, the embodiments of the energy storage system of the present invention include all technical solutions of all embodiments of the control device described above, and the technical effects achieved are also exactly the same, which will not be repeated here.

[0082] In one embodiment of the present invention, the energy storage system includes a plurality of distributed power sources, an energy storage device, a plurality of loads, a plurality of switch devices, and a grid interface;

[0083] The output ends of the plurality of distributed power sources are electrically connected to the control device and the plurality of switch devices in a one-to-one correspondence, and the distributed power sources are used for energy conversion and outputting electric energy;

[0084] Two ends of the energy storage device are electrically connected to the switch device respectively, and the energy storage device is used to store electrical energy and output it when needed;

[0085] The controlled ends of the plurality of switch devices are electrically connected to the control device respectively, and the switch devices are used to switch on or off the paths connecting the two ends of the switch devices according to the switch control signals output by the control device;

[0086] The grid interface is electrically connected to the switch device, and the grid interface is used to access a grid.

[0087] In this embodiment, the distributed power source can be implemented by using power generation equipment such as solar photovoltaic panels, wind turbines, and small hydropower stations. The distributed power source generates electrical energy to power the load or charge the energy storage device. Among them, the output end of the distributed power source is electrically connected to the switching device, and the control device controls the conduction or disconnection of the switching device to achieve the output of the electrical energy generated by the distributed power source. The energy storage device can be set to use a battery of corresponding capacity according to the actual situation of the distributed power source, so as to achieve the storage of excess production capacity of the distributed power source and the supplement when the production capacity of the distributed power source does not meet the load.

[0088] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A control method for an energy storage system, wherein the energy storage system comprises a plurality of distributed power sources, an energy storage device, a plurality of loads, a control device, a voltage conversion device and a plurality of switch devices, characterized in that: The output ends of the plurality of distributed power sources are electrically connected to the input ends of the plurality of switch devices in one-to-one correspondence, the control device is electrically connected to the plurality of distributed power sources, the energy storage device, the plurality of loads, and the controlled ends of the plurality of switch devices respectively, the output ends of the plurality of switch devices are electrically connected to the plurality of loads in one-to-one correspondence, and are connected to the energy storage device; each of the distributed power sources includes a first voltage detection circuit; A switch device is provided between the energy storage device and the load, and two ends of the switch device are electrically connected to the energy storage device and the load respectively; the control method comprises: Acquire a plurality of first voltage detection signals output by a plurality of the first voltage detection circuits, and confirm the output voltage of each of the distributed power sources according to the plurality of first voltage detection signals; Responding to power demands of the plurality of loads, and determining a supply voltage of each of the loads according to the power demands; According to the output voltage of each of the distributed power sources, a load corresponding to the power supply voltage is determined, and a corresponding switch conduction signal is output to the switch device, so that the output voltage of the distributed power source supplies power to the corresponding load; Wherein, the voltage difference between the output voltage of the distributed power supply and the supply voltage of the corresponding load is within a preset voltage difference range; The step of confirming the load corresponding to the power supply voltage according to the output voltage of each of the distributed power sources specifically includes: The output voltage of each of the distributed power sources is divided into a plurality of levels, and the supply voltage of each of the loads is divided into a plurality of levels corresponding to the output voltage of each of the distributed power sources one by one; Wherein, the difference between the maximum voltage value and the minimum voltage value between each level of the output voltage of each of the distributed power sources and the corresponding level of the power supply voltage of each of the loads is less than a preset difference; When it is confirmed that the difference between the output voltage of the distributed power supply and the power supply voltage of the load is greater than a preset voltage difference range, confirm the output voltage of the energy storage device and output a corresponding switch conduction signal to the switch device so that the output voltage of the energy storage device supplies power to the corresponding load; The voltage conversion device is controlled to perform voltage conversion on the output voltage of the distributed power source, and a corresponding switch conduction signal is output to the switch device, so that the output voltage of the distributed power source is used to charge the energy storage device.

2. The method according to claim 1, characterized in that The energy storage system further includes a voltage conversion device, the output voltage of the distributed power source includes a DC output voltage and an AC output voltage, the power supply voltage of each load includes a DC power supply voltage and an AC power supply voltage, and the step of confirming a load corresponding to the power supply voltage according to the output voltage of each distributed power source specifically includes: Determine a load corresponding to a power supply voltage type according to the type of output voltage of each of the distributed power sources; When the type of the output voltage of each of the distributed power sources does not correspond to the type of the power supply voltage of each of the loads, the voltage conversion device is controlled to perform voltage conversion on the output voltage of the distributed power source and output it to the load or the energy storage device.

3. The method according to claim 1, characterized in that The energy storage device includes a second voltage detection circuit, and the control method further includes: Acquire a second voltage detection signal output by a second voltage detection device, and confirm the storage power of the energy storage device according to the second voltage detection signal; When the stored power of the energy storage device is higher than a first preset power, outputting a corresponding switch conduction signal to the switch device to upload the electric energy higher than the preset power to the power grid; When the stored power of the energy storage device is lower than the second preset power, a corresponding switch-off signal is output to the switch device to stop the power output of the energy storage device.

4. The method according to claim 3, characterized in that The energy storage device further includes a temperature detection circuit, a refrigeration device and a heating device, and the control method further includes: Acquire a temperature detection signal output by a temperature detection circuit, and confirm the ambient temperature of the energy storage device according to the temperature detection signal; When the ambient temperature corresponding to the temperature detection signal is higher than a first preset temperature, controlling the refrigeration device to operate until the ambient temperature is lower than the first preset temperature; When the ambient temperature corresponding to the temperature detection signal is lower than the second preset temperature, the heating device is controlled to operate until the ambient temperature is higher than the first preset temperature.

5. A control device, characterized in that: The control device includes: a memory, a processor, and a control program of the energy storage system stored in the memory and running on the processor, wherein the control program is configured to implement the steps of the control method of the energy storage system according to any one of claims 1 to 4.

6. An energy storage system, characterized in that: The energy storage system comprises the control device as claimed in claim 5.

7. The energy storage system according to claim 6, characterized in that: The energy storage system includes multiple distributed power sources, energy storage devices, multiple loads, multiple switch devices, and a grid interface; The output ends of the plurality of distributed power sources are electrically connected to the control device and the plurality of switch devices in a one-to-one correspondence, and the distributed power sources are used for energy conversion and outputting electric energy; Two ends of the energy storage device are electrically connected to the switch device respectively, and the energy storage device is used to store electrical energy and output it when needed; The controlled ends of the plurality of switch devices are electrically connected to the control device respectively, and the switch devices are used to switch on or off the paths connecting the two ends of the switch devices according to the switch control signals output by the control device; The grid interface is electrically connected to the switch device, and the grid interface is used to access a grid.

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