TWI792772B - Energy storage system and method of controlling power thereof - Google Patents

Abstract

An energy storage system is coupled to a power grid through a transformer, and the transformer converts a first power of the power grid and a second power at a low-voltage side of the transformer. The energy storage system includes a power conditioning system, a battery pack, a potential transformer, a current transformer, and a first control module. The power conditioning system converts the second power and a third power for charging or discharging the battery pack. The potential transformer detects a first voltage at a high-voltage side of the transformer, and the current transformer detects the first current flowing through the high-voltage side. The first control module controls the power conditioning system based on the first voltage and the first current of the power grid and a second voltage and a second current of the power conditioning system to adjust the second power to a target power that meets the demand of the power conditioning system or the power grid.

Description

Energy storage system and its power control method

The present invention relates to an energy storage system and its power control method, in particular to an energy storage system with precise power control function and its power control method.

In recent years, with the rapid development of the green energy industry, the power system is no longer a single system that supplies power to loads. More and more subsystems such as backup or renewable energy have been added to construct a complete power system. Among them, due to the increasing shortage of power resources, during the peak period of power consumption, if the power consumption is too large, the cost will increase day by day, so the demand for energy storage systems is also increasing. At the same time, the power of energy storage systems The requirements for the accuracy of regulation are getting higher and higher, so as to effectively improve the stability of power grid operation. However, under the premise of precision requirements, the energy storage system must be equipped with an appropriate detection device to assist the controller of the energy storage system in regulation and increase the ability of precise operation of electric energy.

However, the path from the energy storage system to the grid usually exceeds hundreds of meters, so if precise control is to be performed, the loss on the path must not be ignored. However, the path of power transmission is usually long, and besides the impedance, the path also includes capacitive reactance and inductive reactance which cannot be ignored. Therefore, even if an impedance measurement device is installed, the measurement result will still be inaccurate due to the too long path of power transmission, and There are often signal distortions, resulting in the fact that even if the power has been fine-tuned as much as possible, the adjusted power is still not accurate enough to meet the needs of the power system.

Therefore, how to design an energy storage system with precise power regulation function and its power regulation method, so that even if the power transmission is affected by the loss on the transmission path, the target power finally adjusted by the power regulation system is still not affected by the power transmission. Deviation due to the influence of wear and tear is a major topic of research that the author of this case wants to study.

In order to solve the above problems, the present invention provides an energy storage system with the function of precise power regulation to overcome the problems of the prior art. Therefore, the energy storage system of the present invention is coupled to the grid through a transformer. The transformer includes a high-voltage side and a low-voltage side. The high-voltage side is coupled to the grid, and the transformer is used to convert the first power of the grid and the second power of the low-voltage side. The energy storage system includes a power conditioning system, a battery pack, a voltage comparator, a current comparator, and a first control module. The power conditioning system includes a first terminal and a second terminal, and the first terminal is coupled to the low-voltage side. The battery pack is coupled to the second end, and the power conditioning system is used to convert the second power and the third power for charging and discharging the battery pack. The voltage comparator is coupled to the high voltage side and used for detecting the first voltage of the high voltage side. The current comparator is coupled to the high voltage side and used for detecting the first current of the high voltage side. The first control module is coupled to the power conditioning system, the voltage comparator and the current comparator, and is used for detecting the second voltage and the second current of the first end, and controlling the power conditioning system accordingly. Wherein, the first control module controls the power adjustment system to adjust the second power to the target power based on the first voltage, the first current, the second voltage and the second current.

In order to solve the above problems, the present invention provides a power regulation method of an energy storage system to overcome the problems of the prior art. Therefore, the power control method of the present invention is based on the grid, the transformer to the power The power conditioning system is regulated by regulating the loss on the path of the first end of the system. The transformer is coupled to the grid through the high-voltage side, and the transformer is coupled to the power conditioning system through the low-voltage side to convert the first power of the grid and the second power of the low-voltage side. The power regulation method includes the following steps: (a) detecting the first voltage and the first current of the high voltage side. (b) Detecting a second voltage and a second current at the first terminal. (c) calculating the first electric power through the first voltage and the first current, and calculating the second electric power through the second voltage and the second current. (d) calculating an error amount in response to the loss based on the first power and the second power, and controlling the power adjustment system to adjust the second power to the target power based on the error amount.

The main purpose and function of the present invention is that the energy storage system directly transmits the voltage and current signals of the high-voltage side of the grid to the energy storage system by directly connecting the high-precision current comparator and voltage comparator on the high-voltage side of the grid without The power loss converted by the high and low voltage power equipment makes even if the power transmission is affected by the loss on the transmission path, the target power finally adjusted by the power conditioning system is still not affected by the power transmission loss and will not be deviated, so that it can still provide The power required by the energy storage system.

In order to further understand the technology, means and effects that the present invention adopts to achieve the predetermined purpose, please refer to the following detailed description and accompanying drawings of the present invention. It is believed that the purpose, characteristics and characteristics of the present invention can be obtained from this in depth and For specific understanding, however, the accompanying drawings are provided for reference and illustration only, and are not intended to limit the present invention.

1, 1': power system

100: Grid

10. 10-1~10-n: Transformer

12: High voltage side

14: Low pressure side

20. 20-1~20-n: energy storage system

22: Power conditioning system

22A: first end

22B: second end

222: AC-DC Converter

24: battery pack

242: battery

244:Battery management system

26: Current ratio

28: Pressure comparator

50: The first control module

52: Error calculation unit

54: Control unit

56:Signal modulation unit

60: Second control module

200: load

300: Renewable Energy

P1: First Power

V1: first voltage

I1: first current

P2: Second Power

V2: second voltage

I2: second current

P2': target power

P3: Third Power

Sv: voltage signal

Si: current signal

X: Loss

Er: error amount

Cc: control command

Sc: control signal

Cv: contract capacity

Ca: actual power consumption

M: Margin

(S100)~(S400): Steps

Fig. 1 is a circuit block diagram of the first embodiment of the power system with the function of precise power regulation of the present invention; Fig. 2 is a schematic diagram of the loss of the path impedance of the present invention; Fig. 3 is a control block diagram of the first control module of the present invention; Fig. 4 is a schematic diagram of the power regulation of the power system by the energy storage system of the present invention; Fig. 5 is a second embodiment of the power system with precise power regulation function of the present invention Circuit block diagram; and FIG. 6 is a method flow chart of the power regulation method of the energy storage system of the present invention.

Hereby, the technical content and detailed description of the present invention are described as follows in conjunction with the drawings: please refer to FIG. 1, which is a circuit block diagram of the first embodiment of the power system with the power precision control function of the present invention. The power system 1 includes a transformer 10 and an energy storage system 20 (20 - 1 in FIG. 1 indicates one of a plurality of energy storage systems 20 ), and the transformer 10 includes a high voltage side 12 and a low voltage side 14 . The high voltage side 12 of the transformer 10 is coupled to the grid 100 , and the low voltage side 14 is coupled to the energy storage system 20 . In addition to the energy storage system 20, the power system 1 also includes other loads 200 that can use electricity, or renewable energy sources 300 that supply electricity (indicated by dotted lines), but the technical features of the present invention focus on the energy storage system 20, so The load 200 and the renewable energy source 300 will not be described in detail here.

The energy storage system 20 is a bidirectional power supply system, and its operation mode includes a charging mode in which the energy storage system 20 is charged by the grid 100 and a feeding mode in which the energy storage system 20 feeds power to the grid 100 . The transformer 10 is mainly used as the first power P1 (the voltage can usually be thousands of volts) of the grid 100 on the high voltage side 12 and the second power P2 (the voltage can usually be several thousand volts) of the energy storage system 20 on the low voltage side 14 . 100V) performs bidirectional conversion, and the power transmission direction is determined according to the operation mode of the power system 1 . The energy storage system 20 includes a power conditioning system 22 (PCS; power conditioning system), a battery pack 24, a current comparator 26, a comparator The transformer 28, the first control module 50, and the second control module 60, and the energy storage system 20 is mainly based on the operation mode of the power system 1 to precisely regulate the second power P2.

Specifically, the power conditioning system 22 includes a first end 22A and a second end 22B, the first end 22A is coupled to the low-voltage side 14 , and the second end 22B is coupled to the battery pack 24 . The power conditioning system 22 is a bidirectional conversion device, which may include a bidirectional AC-DC converter 222 for bidirectionally converting the second power P2 and the third power P3 for charging and discharging the battery pack 24 . The voltage comparator 28 is coupled to the high voltage side 12 and is used for detecting the first voltage V1 of the high voltage side 12 and correspondingly providing a voltage signal Sv. The current comparator 26 is also coupled to the high voltage side 12 and used for detecting the first current I1 of the high voltage side 12 and correspondingly providing a current signal Si. Wherein, the voltage comparator 28 may be a CL0.3 voltage comparator, and the current comparator 26 may be a CL0.3 current comparator. The magnification of the voltage comparator 28 and the current comparator 26 is more than 100 times (that is, the turn ratio is more than 100:1), which has a high-precision detection function. The battery pack 24 includes a plurality of batteries 242 and a battery management system 244 , and the batteries 242 are coupled to the second terminal 22B and the battery management system 244 . The battery 242 is used to receive the third power P3 for charging, or provide the third power P3 to the power conditioning system 22 for discharging. The battery management system 244 is used to monitor the power of the battery 242 , which may include monitoring the voltage, current and power of the battery 242 , and may also control current sharing, charging or discharging.

The second control module 60 is coupled to the power conditioning system 22 and the battery pack 24, and is used to set the operation mode of the power conditioning system 22 and the battery pack 24 and the parameters corresponding to the operation mode, so that the power conditioning system 22 is based on the operation mode and parameters The magnitude and transmission direction of the second electric power P2 are adjusted. When the second control module 60 sets the power conditioning system 22 and the battery pack 24 to operate in the charging mode and provides corresponding parameters, the power conditioning system 22 converts the second power P2 to charge the battery pack 24 based on the charging mode and the corresponding parameters . On the contrary, it operates in the feeding mode, and the power conditioning system 22 converts the second electric power P2 to feed the grid 100 based on the feeding mode and corresponding parameters. Wherein, the second control module 60 can be a grid control Site Controller, whose function is to collect information such as relay, power conditioning system 22, and battery 242, and send it to the cloud through the network, so that users can monitor the operating status and control the energy storage system 20 remotely, and No need to attend the case in person. The second control module 60 can control the operation mode of the power conditioning system 22 and set parameters of different functions accordingly. The power conditioning system 22 calculates how much energy should be provided and performs regulation through the operation mode and parameters set by the second control module 60 . It is worth mentioning that a more detailed description of the control method will be further explained later.

The first control module 50 is coupled to the power conditioning system 22, the voltage comparator 28 and the current comparator 26, and is used to control the power conditioning system 22 to adjust the size of the second power P2 according to the voltage signal Sv and the current signal Si, so as to Make the second electric power P2 satisfy the demand of the grid 100 or the battery pack 24 . It is worth mentioning that the first control module 50 can be built into the power conditioning system 22 or can be an independent control module. Further, please refer to FIG. 2 which is a schematic diagram of the loss of the path impedance of the present invention, and refer to FIG. 1 for the combination. In the charging mode or feeding mode, the second electric power P2 must deduct the invalid loss X before generating the power required by the grid 100 (feeding) or the energy storage system 20 (charging). Specifically, due to the path impedance on the path from the grid 100, the transformer 10 to the energy storage system 20 (usually including the auxiliary power loss of the power system 1, cable loss, or the copper loss and iron loss of the transformer 10, etc.), the path impedance Not only will it cause power loss in power transmission, but the capacitive or inductive equivalent impedance on the path will also cause distortion of the power, especially in the case of large power transmission, the phenomenon of distortion will be aggravated.

Therefore, after the power provided by the grid 100 or the energy storage system 20 (ie, the first power P1 or the second power P2 ) passes through the path impedance, in addition to power loss, the power will also be distorted (the sum of the two is called is the loss X) of the path impedance. Therefore, if only the voltage and current signals of the second power P2 are detected on the low-voltage side 14, and the corresponding control is performed accordingly, the power regulation of the energy storage system 20 will be affected due to the loss caused by the path impedance. , resulting in insufficient power regulation of the energy storage system 20 Accurate, so that there is still a gap between the power required by the energy storage system 20 and the actually measured second power P2 (conversely, the same is true for the first power P1). On the contrary, since the voltage comparator 28 and the current comparator 26 are detection devices, they are not used for the transmission of large power, so the capacitive or inductive equivalent impedances such as copper loss and iron loss are extremely low (compared with the transformer 10 ), the detected signal is less likely to be distorted, and is suitable for providing the energy storage system 20 to precisely regulate the second electric power P2.

Furthermore, in addition to detecting the second voltage V2 and the second current I2 of the first terminal 22A through the detection unit (not shown), the first control module 50 also passes through the voltage comparator 28 and the current comparator. 26 to detect the first voltage V1 and the first current I1 of the high voltage side 12, and control the power conditioning system 22 accordingly. Specifically, the first control module 50 controls the power adjustment system 22 to adjust the second power P2 to the target power P2' based on the first voltage V1, the first current I1, the second voltage V2 and the second current I2. In the charging mode, the target power P2' is the power required by the power conditioning system 22 after the loss of the path impedance, and in the feed mode, the target power P2' is the power that still meets the power grid 100 after the loss of the path impedance. demanded electricity.

For example, assuming that the first power P1 demanded by the grid 100 requires 10VA (volt-ampere; the unit represents AC power), the second control module 60 sets the operation mode of the power conditioning system 22 and the battery pack 24 to the feed mode, and provides corresponding parameters. The power conditioning system 22 converts the second power P2 corresponding to 10VA to feed the grid 100 based on the feeding mode and corresponding parameters. At this time, it is assumed that the loss of the path impedance is 2VA, so that the first power P1 actually received by the grid 100 is only 8VA, which does not meet the power demanded by the grid 100 . At this time, the first control module 50 knows that the first electric power P1 actually received by the grid 100 is only 8VA by receiving the voltage signal Sv and the current signal Si, and detects the second voltage V2 and the second voltage of the first terminal 22A. According to the current I2, it is known that the power conditioning system 22 provides the second power P2 corresponding to 10VA. Then, the first control module 50 adjusts the power conditioning system by controlling the power conditioning system 22 The second electric power P2 output by 22 is 12VA. However, the loss of the path impedance is not a linear change, and the product of volt-ampere will be different due to the adjustment of the current. Therefore, assuming that the path impedance loss under this condition is 2.2VA, the first power P1 actually received by the grid 100 is 9.8VA, which still does not meet the power demanded by the grid 100 . Thereafter, the first control module 50 will repeatedly adjust until the second power P2 is adjusted to the target power P2', which meets the 10VA power required by the grid 100.

On the other hand, since in actual conditions, the path between the grid 100 and the energy storage system 20 may be very long, from the source (such as but not limited to power companies, general substations, etc.) to the terminal (energy storage system 20) is mostly will exceed hundreds of meters (indicated by dashed lines in Fig. 1). Therefore, it is very difficult to measure the impedance of the path to calculate the loss and adjust the second power P2 precisely accordingly. The reason is that it is very difficult to set up the impedance measurement circuit on such a long path, and the measurement result is not accurate enough due to the limitation of the long distance. Therefore, through the precise control method of the present invention, the second power P2 can be accurately controlled to adjust the second power P2 to the target power P2' without additionally installing an impedance measurement circuit on the power system 1 .

Please refer to FIG. 3, which is a control block diagram of the first control module of the present invention, and refer to FIGS. 1-2 for complex cooperation. The first control module 50 includes an error calculation unit 52 , a control unit 54 and a signal modulation unit 56 . The control unit 54 is coupled to the error calculation unit 52 and the signal modulation unit 56, the error calculation unit 52 is coupled to the first end 22A (through the detection unit), the voltage comparator 28 and the current comparator 26, and the signal modulation unit 56 is coupled to the power Regulating system 22. The error calculation unit 52 calculates the first power P1 based on the signal corresponding to the first voltage V1 and the first current I1, and calculates the second power P2 based on the signal corresponding to the second voltage V2 and the second current I2. Then, the error calculation unit 52 calculates an error amount Er in response to the loss X based on the first electric power P1 and the second electric power P2. The control unit 54 receives the error amount Er, and calculates the error amount Er to calculate the target voltage and target current, so as to provide the control command Cc corresponding to the target power P2' to the signal regulator. Control unit 56. The signal modulation unit 56 receives the control command Cc, and based on the control command Cc modulates the control signal Sc in response to the target power to the power conditioning system 22 (the bidirectional AC-DC converter 222 inside the power conditioning system), so that the first control module 50 Based on the error amount Er, the power regulating system 22 is controlled to adjust the second power P2 to the target power P2 ′ (that is, to adjust the second voltage V2 and the second current I2 to the target voltage and target current).

It is worth mentioning that in one embodiment of the present invention, the first control module 50 is a programmable controller (that is, written into the control software), but it is not limited thereto, the first control module 50 can also be a combination The logic controller may be composed of circuits. In addition, the control unit 54 can calculate the target power P2' through, for example but not limited to, an iterative calculation method, but it is not limited thereto. Any calculation method that can calculate the final required modulated power value should be included in the scope of this embodiment.

Please refer to FIG. 4 , which is a schematic diagram of the power regulation of the power system by the energy storage system of the present invention, and refer to FIGS. 1-3 for complex cooperation. For example, the parameters set by the second control module 60 include the contracted capacity Cv of the grid 100. When the actual electricity consumption Ca of the grid 100 exceeds the contracted capacity Cv, the power management unit (such as a power plant or a power company, etc.) Additional electricity charges may apply. When the actual electricity consumption Ca is below the contracted capacity Cv, the basic fee will be charged accordingly. Therefore, the power conditioning system 22 will obtain the contracted capacity Cv and the actual power consumption Ca of the grid 100 according to the parameters provided by the second control module 60 . Then adjust the size of the second power P2 based on the contracted capacity Cv, the actual power consumption Ca of the grid 100, and the stored energy of the battery pack 24, so as to adjust the first power P1 so that the actual power consumption Ca is lower than the contracted capacity Cv .

Taking Fig. 4 as an example, the vertical axis represents the capacity of the power grid 100 (the unit is VA), the horizontal axis represents the time (taking a day as an example), and the curve represents the actual power consumption Ca of a specific unit (such as a company, factory building, etc.) in a day . It can be seen from Figure 4 that the actual electricity consumption Ca of a specific unit in a day is higher at 9~11 o'clock and 13~17 o'clock peak, which exceeds the contracted capacity Cv and may be charged additional electricity charges by the power management unit. Therefore, at 9 o'clock to 11 o'clock and 13 o'clock to 17 o'clock, the power conditioning system 22 adjusts the amount of the second power P2 fed to the grid 100 based on the contracted capacity Cv, the actual power consumption Ca of the grid 100, and the stored energy of the battery pack 24. Size, in order to provide the first power P1 to cut the additional power consumption at 9~11 o'clock and 13~17 o'clock. On the other hand, at 0-9 o'clock and 17-0 o'clock, due to possibly abnormal working hours, the actual power consumption Ca is lower than the contracted capacity Cv. Therefore, the power conditioning system 22 adjusts the size of the second electric power P2 for charging the battery pack 24 based on the contracted capacity Cv, the actual power consumption Ca of the grid 100, and the stored energy of the battery pack 24, so as to make up for the power consumed by the battery pack 24 during discharge. electricity. Under the general structure of the power system 1, the main system of the energy storage system 20 must precisely regulate the first power P1 and the third power P3 to meet the power demanded by the grid 100 and the battery pack 24, and avoid the energy storage system 20 from feeding After electricity or charging, due to the loss X of the path impedance, the actual power consumption Ca is still higher than the contracted capacity Cv.

The precise control method of the feeding mode has been exemplified above, and the precise control method of the charging mode is exemplified here. Assume that the third power P3 required by the battery pack 24 needs 10W (Watt; the unit represents DC power), and the margin M between the actual power consumption Ca and the contracted capacity Cv is 10VA. The second control module 60 sets the operation mode of the power conditioning system 22 and the battery pack 24 to the charging mode, and provides corresponding parameters. The power conditioning system 22 intends to extract the second power P2 corresponding to 10W to charge the battery pack 24 based on the charging mode and corresponding parameters. At this time, assuming that the loss of the path impedance is 2VA, the first power P1 actually provided by the grid 100 is 12VA, so that the actual power consumption Ca of the grid 100 exceeds the contracted capacity Cv. At this time, the first control module 50 knows that the first power P1 actually provided by the grid 100 is 12VA by receiving the voltage signal Sv and the current signal Si, and detects the second voltage V2 and the second current of the first terminal 22A. I2 means that the power conditioning system 22 has received the second power P2 of 10VA. Then, in order to meet the fact that the actual power consumption Ca is lower than the contracted capacity Cv, and to avoid being charged by the power management unit for additional power consumption, Therefore, the first control module 50 adjusts the second power P2 received by the power conditioning system 22 to be 8VA by controlling the power conditioning system 22 . However, the loss of the path impedance is not a linear change, and the product of volt-ampere will be different due to the adjustment of the current. Therefore, assuming that the loss of the path impedance under this condition is 1.8VA, the first power P1 actually provided by the grid 100 is 9.8VA (the margin M still has 0.2VA), which still does not meet the power demanded by the power conditioning system 22 (this The demanded power is the actual power consumption Ca equal to the contract capacity Cv). Thereafter, the first control module 50 will repeatedly adjust until the second power P2 is adjusted to the target power P2', which satisfies the power demanded by the power regulation system 22 (that is, the margin M is close to 0).

Please refer to FIG. 5 , which is a circuit block diagram of the second embodiment of the power system with precise power regulation function according to the present invention. Refer to FIGS. 1-4 for complex cooperation. The difference between the power system 1' of this embodiment and the power system 1 in FIG. indicated by dashed lines). Each energy storage system 20 can share a single voltage comparator 28 to detect the first voltage V1, and respectively use the current comparator 26 to detect the respective first current I1. The second control module 60 is coupled to the power conditioning system 22 and the battery pack 24 of each energy storage system 20-1~20-n, and is used to set the operation mode of each power conditioning system 22 and the battery pack 24 and correspondingly The parameters of the operation mode enable each power regulation system 22 to adjust the size and transmission direction of the second power P2 based on the operation mode and parameters, and the size may be different. It is worth mentioning that in one embodiment of the present invention, the detailed circuit structure and operation method of the power system 1' in FIG. 5 are similar to those of the power system 1 in FIG.

Please refer to FIG. 6 , which is a flow chart of the power regulation method of the energy storage system of the present invention, and refer to FIGS. 1-5 for complex cooperation. The power regulation method of the energy storage system 20 is mainly to precisely regulate the second power P2 according to the operation mode of the power system 1 , and the power regulation method first includes detecting the first voltage and the first current at the high voltage side ( S100 ). A preferred implementation method is to detect the first voltage V1 of the high-voltage side 12 through the high-precision voltage comparator 28 to provide a voltage signal Sv accordingly, and to detect the first voltage V1 of the high-voltage side 12 through the high-precision current comparator 26. The first current I1 at the high voltage side 12 is measured to provide a current signal Si accordingly. Then, detect a second voltage and a second current at the first end (S200). A preferred implementation manner is to detect the second voltage V2 and the second current I2 of the first terminal 22A through a self-detection detection unit (not shown) of the power adjustment system 22 . Then, the first power is calculated by the first voltage and the first current, and the second power is calculated by the second voltage and the second current (S300). In a preferred embodiment, the error calculation unit 52 receives the voltage signal Sv and the current signal Si, and calculates the first power P1 based on the signals corresponding to the first voltage V1 and the first current I1. On the other hand, the error calculation unit 52 also receives the signal fed back from the first terminal 22A, and calculates the second power P2 based on the signals corresponding to the second voltage V2 and the second current I2.

Finally, an error amount in response to loss is calculated based on the first power and the second power, and the power adjustment system is controlled based on the error amount to adjust the second power to the target power ( S400 ). A preferred embodiment is that the error calculation unit 52 calculates the error amount Er corresponding to the loss X of the path impedance based on the first power P1 and the second power P2, and the control unit 54 calculates the error amount Er to provide the corresponding target The control command Cc of the power P2 ′ is sent to the signal modulation unit 56 . The signal modulation unit 56 receives the control command Cc, and modulates the control signal Sc in response to the target power to the power conditioning system 22 based on the control command Cc, so that the first control module 50 controls the power conditioning system 22 to convert the second power to the power conditioning system 22 based on the error amount Er. P2 is adjusted to the target power P2' (that is, the second voltage V2 and the second current I2 are adjusted to the target voltage and target current). It is worth mentioning that, in one embodiment of the present invention, the detailed power regulation method of the energy storage system 20 can refer to FIGS. 1-5 and their corresponding descriptions, and will not be repeated here.

To sum up, the main purpose and effect of the present invention is that the energy storage system directly transmits the voltage and current signals of the high voltage side of the grid to the energy storage system by directly connecting the high-precision current comparator and voltage comparator on the high voltage side of the grid. Medium and no longer through the power consumption of high and low voltage power equipment conversion, so that even if the power transmission is affected by the loss on the transmission path, the final adjustment target of the power conditioning system The power remains unaffected by power transmission losses, allowing it to still provide enough power to meet the needs of the energy storage system.

However, the above description is only a detailed description and drawings of preferred embodiments of the present invention, but the features of the present invention are not limited thereto, and are not intended to limit the present invention. The entire scope of the present invention should be applied for as follows The scope of the patent shall prevail, and all embodiments that conform to the spirit of the patent scope of the present invention and its similar changes shall be included in the scope of the present invention, and any person familiar with the art can easily think of it in the field of the present invention Changes or modifications can be covered by the scope of the following patents in this case.

1: Power system

100: Grid

10:Transformer

12: High voltage side

14: Low pressure side

20: Energy storage system

22: Power conditioning system

22A: first end

22B: second end

222: AC-DC Converter

24: battery pack

242: battery

244:Battery management system

26: Current ratio

28: Pressure comparator

50: The first control module

60: Second control module

200: load

300: Renewable Energy

P1: First Power

V1: first voltage

I1: first current

P2: Second Power

V2: second voltage

I2: second current

P2': target power

P3: Third Power

Sv: voltage signal

Si: current signal

Claims (16)

An energy storage system is coupled to a grid through a transformer, the transformer includes a high-voltage side and a low-voltage side, the high-voltage side is coupled to the grid, and the transformer is used to convert a first power of the grid and the low-voltage side A second electric power, the energy storage system includes: a power conditioning system, including a first terminal and a second terminal, the first terminal is coupled to the low-voltage side; a battery pack, coupled to the second terminal, and The power conditioning system is used to convert the second power and a third power for charging and discharging the battery pack; a voltage comparator, coupled to the high voltage side, and used to detect a first voltage of the high voltage side; a a current comparator coupled to the high voltage side and used to detect a first current on the high voltage side; and a first control module coupled to the power regulation system, the voltage comparator and the current comparator, and used to detect a second voltage and a second current of the first terminal, and control the power conditioning system accordingly; wherein, the first control module is based on the first voltage, the first current, the second The voltage and the second current control the power adjustment system to adjust the second power to a target power. The energy storage system according to claim 1, wherein the path from the power grid to the power conditioning system includes a path impedance; the target power is the power that still meets the demand of the power conditioning system after passing through a loss in the path impedance, or After passing through the losses, the power that still satisfies the needs of the grid. The energy storage system according to claim 1, wherein the first control module includes: an error calculation unit coupled to the first terminal, the voltage comparator and the current comparator; a control unit coupled to the error a calculation unit; and a signal modulation unit coupled to the control unit and the power conditioning system; wherein, the error calculation unit calculates the first power based on the first voltage and the first current, and based on the second voltage and the The second current calculates the second power based on the first power and the second power calculating an error amount; the control unit calculates the error amount to obtain a control command corresponding to the target power, and the signal modulation unit modulates a control signal corresponding to the target power to the power conditioning system based on the control command , so as to adjust the second electric power to the target electric power. The energy storage system as described in claim 1 further includes: a second control module, coupled to the power conditioning system and the battery pack, and used to set an operation mode and a corresponding operation mode of the power conditioning system and the battery pack A parameter in the operation mode; wherein, the power conditioning system adjusts the magnitude and transmission direction of the second power based on the operation mode and the parameter. The energy storage system as described in claim 4, wherein when the second control module sets the operation mode to a feeding mode, the power conditioning system converts the second power pair based on the feeding mode and the corresponding parameter The grid feeds power; when the second control module sets the operation mode as a charging mode, the power conditioning system converts the second power to charge the battery pack based on the charging mode and the corresponding parameters. The energy storage system as described in claim 4, wherein the parameter includes a contracted capacity of the power grid, and the power conditioning system adjusts the first power condition based on the contracted capacity, an actual power consumption of the power grid, and a stored energy of the battery pack 2. The size of the electric power. The energy storage system as claimed in claim 1, wherein the battery pack includes: a plurality of batteries, coupled to the second end, and used to receive or provide the third power; and a battery management system, coupled to the batteries , and is used to perform a power monitoring on the batteries. The energy storage system according to claim 1, wherein the power conditioning system includes a bidirectional AC-DC converter, and the bidirectional AC-DC converter is used for bidirectionally converting the second power and the third power. The energy storage system as claimed in item 1, wherein the multiplier ratio of the pressure comparator and the current comparator is more than 100 times. A power regulation method for an energy storage system, which regulates the power regulation system based on a loss on the path from a power grid, a transformer to a first end of the power regulation system, the transformer is coupled to the power grid through a high-voltage side, And the transformer is coupled to the power conditioning system through a low-voltage side to convert a first power of the grid and a second power of the low-voltage side; the power regulation method includes the following steps: detecting a first power of the high-voltage side voltage and a first current; detect a second voltage and a second current of the first terminal; calculate the first power through the first voltage and the first current, and use the second voltage and the second calculating the second power; and calculating an error amount in response to the loss based on the first power and the second power, and controlling the power adjustment system to adjust the second power to a target power based on the error amount. The power regulation method as described in Claim 10, further comprising the following steps: calculating the error amount to obtain a control command corresponding to the target power; and modulating a control signal corresponding to the target power based on the control command , and adjust the second power to the target power through the control signal. The power regulating method as described in claim 10, wherein the energy storage system includes a battery pack coupled to the power regulating system, and the power regulating method further includes the following steps: converting the second electric power and charging the battery pack A third electric power is discharged. The power control method as described in claim 12 further includes the following steps: Setting an operation mode of the power conditioning system and the battery pack and a parameter corresponding to the operation mode; and adjusting the magnitude and transmission direction of the second electric power based on the operation mode and the parameter. The power regulation method as described in claim 13, further comprising the following steps: setting the power regulation system and the battery pack to operate in a feeding mode; and converting the second power pair based on the feeding mode and the corresponding parameter The grid feeds. The power regulation method as described in claim 13, further comprising the steps of: setting the power regulation system and the battery pack to operate in a charging mode; and converting the second power to the battery based on the charging mode and the corresponding parameters group charging. The power regulation method as described in claim 13 further includes the following steps: adjusting the size of the second power based on the contracted capacity, an actual capacity of the grid, and a stored energy of the battery pack.

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