ENERGY STORAGE SYSTEM AND POWER SUPPLY METHOD THEREOF
An energy storage system and a power supply method thereof are provided. First and second energy storage devices are connected in series between an AC power source and a load. When the AC power source is normal, the AC power source is used to charge the first energy storage device and provided to the second energy storage device for charging. When the AC power source is abnormal, an output of the first energy storage device is switched from the AC power source to a first energy storage power source, and the second energy storage device is disabled from using the first energy storage power source for charging. A power source provided by the first energy storage device or a second energy storage power source provided by the second energy storage circuit is output to the load according to a power supply state of the first energy storage device.
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This application claims the priority benefit of Taiwan application serial no. 110104890, filed on Feb. 9, 2021. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.
TECHNICAL FIELDThe disclosure relates to a power supply apparatus, and more particularly to an energy storage system and a power supply method thereof.
BACKGROUNDIn order to ensure stable operation of electrical equipment, a power supply apparatus with dual input power sources is commonly adopted to supply power to the electrical equipment. A power supply apparatus with dual input power sources is commonly provided with an automatic transfer switch (ATS) that automatically switches the power supply source of the electrical equipment from the main input power source to the backup input power source when the main input power source is abnormal, so as to prevent the electrical equipment from failing to operate due to power supply interruption, thereby making the electrical equipment reliable.
Although the backup input power source can solve power supply problems of the electrical equipment, the power capacity of the backup input power source is generally limited, so the time during which the backup input power source can provide power to the electrical equipment is limited as well. Therefore, how to increase the power capacity of the backup input power source to extend the power supply time of the backup input power source has become an issue for people of ordinary skills in the art to work on.
SUMMARYThe disclosure provides an energy storage system and a power supply method thereof, which can effectively increase the total discharge capacity of the energy storage system and greatly extend the power supply time.
An energy storage system according to an embodiment of the disclosure includes a first energy storage device and a second energy storage device. The input terminal of the first energy storage device is coupled to an AC power source. The second energy storage device and the first energy storage device are connected in series between the AC power source and a load. The input terminal and output terminal of the second energy storage device are respectively coupled to the input terminal of the first energy storage device and the load. The first energy storage device includes a first energy storage circuit, a first switching circuit, and a first control circuit. The first energy storage circuit is coupled to the AC power source and uses the AC power source for charging. The first switching circuit is coupled to the first energy storage circuit, the input terminal and output terminal of the first energy storage device. The first control circuit is coupled to the first energy storage circuit, the first switching circuit, and the input terminal of the first energy storage device, controlling the first switching circuit to switch between outputting the AC power source and outputting a first energy storage power source provided by the first energy storage circuit to the output terminal of the first energy storage device according to whether the AC power source is abnormal. The second energy storage device and the first energy storage device are connected in series between the AC power source and the load. The input terminal and output terminal of the second energy storage device are respectively coupled to the output terminal of the first energy storage device and the load. The second energy storage device includes a second energy storage circuit, a second switching circuit, and a second control circuit. The second energy storage circuit is coupled to the input terminal of the second energy storage device and uses the AC power source provided by the first energy storage device for charging. The second switching circuit is coupled to the second energy storage circuit, the input terminal and output terminal of the second energy storage device. The second control circuit is coupled to the second energy storage circuit, the second switching circuit, and the input terminal of the second energy storage device, controlling the second switching circuit to switch between outputting a power source provided by the first energy storage device and outputting a second energy storage power source provided by the second energy storage circuit to the load according to a power supply state of the first energy storage device.
The disclosure further provides a power supply method of an energy storage system. The energy storage system includes a first energy storage device and a second energy storage device connected in series between an AC power source and a load. The power supply method of the energy storage system includes the following steps. It is detected whether the AC power source is abnormal. If the AC power source is normal, the first energy storage device is charged by using the AC power source, and the AC power source is provided to the second energy storage device for charging. If the AC power source is abnormal, an output of the first energy storage device is switched from the AC power source to a first energy storage power source, and the second energy storage device is disabled from using the first energy storage power source for charging. A power source provided by the first energy storage device or a second energy storage power source provided by the second energy storage circuit is output to the load according to a power supply state of the first energy storage device.
Based on the above, according to the embodiments of the disclosure, the first energy storage device and the second energy storage device are connected in series between the AC power source and the load. When the AC power source is normal, the first energy storage device may be charged by using the AC power source, and the AC power source may be provided to the second energy storage device for charging. When the AC power source is abnormal, the output of the first energy storage device may be switched from the AC power source to the first energy storage power source, and the second energy storage device may be disabled from using the first energy storage power source for charging. In addition, the power source provided by the first energy storage device or the second energy storage power source provided by the second energy storage circuit is output to the load according to the power supply state of the first energy storage device. This way, by connecting the first energy storage device and the second energy storage device in series between the AC power source and the load and adjusting the power supply of the first energy storage device and the second energy storage device according to the power supply state of the AC power source, the total discharge capacity of the energy storage system may be effectively increased, and the power supply time may be greatly extended.
The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure.
Reference will now be made in detail to the present preferred embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
The first energy storage circuit 106 may use the power provided by the AC power source 118 for charging. According to whether the power supply condition of the AC power source 118 is abnormal, the first control circuit 110 may control the first switching circuit 108 to switch between outputting the AC power source 118 and outputting a first energy storage power source (which is also an AC power source) provided by the first energy storage circuit 106 to the output terminal of the first energy storage device 102. A power supply abnormality of the AC power source 118 may result from an abnormal voltage or an abnormal frequency of the AC power source 118. Due to such abnormality, the AC power source 118 may be unable to be supplied normally. According to the power supply state of the output terminal of the first energy storage device 102, the second control circuit 116 of the second energy storage device 104 may switch between outputting a power source provided by the first energy storage device 102 and outputting a second energy storage power source provided by the second energy storage circuit 114 to the load 120 to supply the load 120 with the power required for the load 120 to operate.
In more detail, when the power supply condition of the AC power source 118 is normal, the first energy storage device 102 is in a bypass mode. The AC power source 118 provided by the first energy storage device 102 may serve to supply power to the load 120 while charging the second energy storage circuit 114. When the first control circuit 110 detects that the AC power source 118 is abnormal, the first energy storage device 102 enters a battery mode. At the time, the first control circuit 110 may control the first switching circuit 108 to switch an output of the first energy storage device 102 to the first energy storage power source provided by the first energy storage circuit 106 to continuously supply power to the load 120. In order to prevent the first energy storage power source provided by the first energy storage circuit 106 from being provided to the second energy storage circuit 114, the first control circuit 110 may control the first energy storage circuit 106 to output the first energy storage power source that conforms to a first preset signal characteristic during a first preset period to notify the second energy storage device 104 that the current power supply source is the first energy storage circuit 106. Since the second energy storage device 104 has stored the first preset signal characteristic in advance, the second energy storage device 104 may disable the second energy storage circuit 114 from using the power source provided by the first energy storage device 102 for charging when detecting that the power source provided by the first energy storage device 102 conforms to the first preset signal characteristic during the first preset period.
The first preset signal characteristic includes a first preset frequency change rule, which is a preset power source frequency change sequence and may, for example, serve to switch multiple frequency values of the power source provided by the first energy storage device according to a first sequence during the first preset period, where each frequency value is maintained for a corresponding period of time. For example,
Correspondingly, the steps of the second energy storage device 104 determining whether the power source provided by the first energy storage device 102 conforms to the first preset signal characteristic during the first preset period may be as shown in
It should be noted that the frequency adjustment values of the power source included in the first preset signal characteristic and the length of cycles during which the adjusted frequency of the power source is maintained are merely described as examples. In other embodiments, the number of times of frequency adjustment, the adjusted frequency values, the change sequence of frequency values, and the length of cycles during which the frequency is maintained are not limited to the above example. For example, the change sequence of frequency values may be, for example, →62 Hz→61 Hz→60 Hz→59 Hz→58 Hz→60 Hz, and the length of cycles during which each frequency is maintained may be, for example, 5 cycles, 5 cycles, 10 cycles, 6 cycles, 5 cycles, and 5 cycles in sequence.
Moreover, when the second control circuit 116 detects that the first energy storage device 102 stops providing the power source, such as when the first energy storage circuit 106 runs out of power, the second control circuit 116 may enter the battery mode and control the second energy storage circuit 114 to provide the second energy storage power source to the load 120 through the second switching circuit 112 to extend the time of the energy storage system supplying power to the load 120.
When the first control circuit 110 determines that the AC power source 118 returns to normal from an abnormal state, the first control circuit 110 may control the first switching circuit 108 to switch the output of the first energy storage device 102 to the AC power source 118, and control the first energy storage circuit 106 to output the first energy storage power source that conforms to a second preset signal characteristic during a second preset period before the output of the first energy storage device 102 is switched to the AC power source 118. Similarly, the second energy storage device 104 has also stored the second preset signal characteristic in advance. Similarly, the second preset signal characteristic may include a second preset frequency change rule. The second preset frequency change rule may, for example, serve to switch multiple frequency values of the power source provided by the first energy storage device according to a second sequence during the second preset period, where each of the frequency values is maintained for a corresponding period of time. It should be noted that the second preset frequency change rule included in the second preset signal characteristic is different from the first preset frequency change rule included in the first preset signal characteristic. That is, the first preset signal characteristic is different from the second preset signal characteristic.
For example,
Correspondingly, the steps of the second energy storage device 104 determining whether the power source provided by the first energy storage device 102 conforms to the second preset signal characteristic during the second preset period may be as shown in
The first battery 704 and the second battery 712 may be configured to store electric power. The first conversion circuit 702 and the second conversion circuit 710 may be controlled by the first controller 708 and the second controller 716 respectively to convert the electric power stored in the first battery 704 and the second battery 712 to AC power source, and respectively adopt the converted AC power source as the first energy storage power source and the second energy storage power source. The first charging circuit 706 may be controlled by the first controller 708 to charge the first battery 704 by using the AC power source 118. The second charging circuit 714 may be controlled by the second controller 716 to charge the second battery 712 by using the AC power source 118 provided by the first energy storage device 102. In more detail, the first controller 708 and the second controller 716 may further detect the power storage states of the first battery 704 and the second battery 712 respectively, and control the charging and discharging of the first battery 704 and the second battery 712 according to the power storage states of the first battery 704 and the second battery 712 to extend the service lives of the first battery 704 and the second battery 712. In addition, the first controller 708 may further determine whether the AC power source 118 is abnormal according to the first detecting signal provided by the first detecting circuit 602, and control the first switching circuit 108 to switch between outputting the AC power source 118 and outputting the first energy storage power source provided by the first conversion circuit 702 to the output terminal of the first energy storage device 102 according to whether the AC power source 118 is abnormal. The second controller 716 may further determine the power supply state of the first energy storage device 102 according to the second detecting signal provided by the second detecting circuit 604, and control the second switching circuit 112 to switch between outputting the power source provided by the first energy storage device 102 and outputting the second energy storage power source provided by the second conversion circuit 710 to the load 120 according to the power supply state of the first energy storage device 102. Since the technical means of the first controller and the second controller are similar to the technical means of the first control circuit 110 and the second control circuit 116 described above, the same technical means will not be repeated in the following.
In summary, according to the embodiments of the disclosure, the first energy storage device and the second energy storage device are connected in series between the AC power source and the load. When the AC power source is normal, the first energy storage device is charged by using the AC power source, and the AC power source may be provided to the second energy storage device for charging. When the AC power source is abnormal, the output of the first energy storage device may be switched from the AC power source to the first energy storage power source, and the second energy storage device may be disabled from using the first energy storage power source for charging. In addition, the power source provided by the first energy storage device or the second energy storage power source provided by the second energy storage circuit is output to the load according to the power supply state of the first energy storage device. This way, by connecting the first energy storage device and the second energy storage device in series between the AC power source and the load and adjusting the power supply of the first energy storage device and the second energy storage device according to the power supply state of the AC power source, the total discharge capacity of the energy storage system may be effectively increased, and the power supply time may be greatly extended. Moreover, multiple energy storage devices may be connected in series according to the power demand, instead of being limited to two energy storage devices. In addition, in some embodiments, the frequency of the power source provided by the first energy storage device may be adjusted to notify the changes of the power supply source to the second energy storage device. Therefore, no additional communication line is required.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the disclosure without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims and their equivalents.
Claims
1. An energy storage system, comprising:
- a first energy storage device, having an input terminal coupled to an AC power source and comprising: a first energy storage circuit, which is coupled to the AC power source and uses the AC power source for charging; a first switching circuit, which is coupled to the first energy storage circuit and the input terminal and an output terminal of the first energy storage device; and a first control circuit, which is coupled to the first energy storage circuit, the first switching circuit, and the input terminal of the first energy storage device, and, according to whether the AC power source is abnormal, controls the first switching circuit to switch between outputting the AC power source and outputting a first energy storage power source provided by the first energy storage circuit to the output terminal of the first energy storage device; and
- a second energy storage device, connected in series with the first energy storage device between the AC power source and a load, having an input terminal and an output terminal respectively coupled to the output terminal of the first energy storage device and the load, and comprising: a second energy storage circuit, which is coupled to the input terminal of the second energy storage device and uses the AC power source provided by the first energy storage device for charging; a second switching circuit, which is coupled to the second energy storage circuit, and the input terminal and the output terminal of the second energy storage device; and a second control circuit, which is coupled to the second energy storage circuit, the second switching circuit, and the input terminal of the second energy storage device, and, according to a power supply state of the first energy storage device, controls the second switching circuit to switch between outputting a power source provided by the first energy storage device and outputting a second energy storage power source provided by the second energy storage circuit to the load.
2. The energy storage system according to claim 1, wherein the first control circuit, when detecting that the AC power source is abnormal, controls the first switching circuit to switch an output of the first energy storage device to the first energy storage power source, and controls the first energy storage circuit to output the first energy storage power source that conforms to a first preset signal characteristic during a first preset period, and the second control circuit, when detecting that the power source provided by the first energy storage device conforms to the first preset signal characteristic, disables the second energy storage circuit from using the power source provided by the first energy storage device for charging.
3. The energy storage system according to claim 2, wherein the first control circuit, when determining that the AC power source returns to normal, controls the first switching circuit to switch the output of the first energy storage device to the AC power source, and controls the first energy storage circuit to output the first energy storage power source that conforms to a second preset signal characteristic during a second preset period before the output of the first energy storage device is switched to the AC power source.
4. The energy storage system according to claim 3, wherein the second control circuit, when the power source output by the first energy storage device conforms to the second preset signal characteristic, enables the second energy storage circuit to use the power source provided by the first energy storage device for charging.
5. The energy storage system according to claim 3, wherein the first preset signal characteristic is different from the second preset signal characteristic.
6. The energy storage system according to claim 3, wherein the first preset signal characteristic comprises a first preset frequency change rule, and the second preset signal characteristic comprises a second preset frequency change rule.
7. The energy storage system according to claim 6, wherein the first preset frequency change rule serves to switch a plurality of frequency values of the power source provided by the first energy storage device according to a first sequence during the first preset period, wherein each of the frequency values is maintained for a corresponding period of time.
8. The energy storage system according to claim 6, wherein the second preset frequency change rule serves to switch a plurality of frequency values of the power source provided by the first energy storage device according to a second sequence during the second preset period, wherein each of the frequency values is maintained for a corresponding period of time.
9. The energy storage system according to claim 1, wherein the second control circuit, when detecting that the first energy storage device stops providing the power source, controls the second energy storage circuit to provide the second energy storage power source to the load through the second switching circuit.
10. The energy storage system according to claim 1, wherein the first control circuit comprises:
- a first detecting circuit, which is coupled to the input terminal of the first energy storage device and detects the AC power source to generate a first detecting signal, wherein the first control circuit determines whether the AC power source is abnormal according to the first detecting signal.
11. The energy storage system according to claim 1, wherein the second control circuit comprises:
- a second detecting circuit, which is coupled to the input terminal of the second energy storage device and detects the power source provided by the first energy storage device to generate a second detecting signal, wherein the second control circuit determines the power supply state of the first energy storage device according to the second detecting signal.
12. A power supply method of an energy storage system, wherein the energy storage system comprises a first energy storage device and a second energy storage device connected in series between an AC power source and a load, and the power supply method of the energy storage system comprises:
- detecting whether the AC power source is abnormal;
- if the AC power source is normal, charging the first energy storage device by using the AC power source and providing the AC power source to the second energy storage device for charging;
- if the AC power source is abnormal, switching an output of the first energy storage device from the AC power source to a first energy storage power source and disabling the second energy storage device from using the first energy storage power source for charging; and
- outputting a power source provided by the first energy storage device or a second energy storage power source provided by the second energy storage circuit to the load according to a power supply state of the first energy storage device.
13. The power supply method of the energy storage system according to claim 12, comprising:
- when detecting that the AC power source is abnormal, controlling the first energy storage device to output the first energy storage power source that conforms to a first preset signal characteristic during a first preset period;
- detecting whether the power source provided by the first energy storage device conforms to the first preset signal characteristic;
- if the power source provided by the first energy storage device does not conform to the first preset signal characteristic, outputting the power source provided by the first energy storage device to the load and charging the second energy storage device by using the power source provided by the first energy storage device; and
- if the power source provided by the first energy storage device conforms to the first preset signal characteristic, outputting the power source provided by the first energy storage device to the load and disabling the second energy storage device from using the power source provided by the first energy storage device for charging.
14. The power supply method of the energy storage system according to claim 13, wherein when it is detected that the AC power source returns to normal, the output of the first energy storage device is switched to the AC power source, and the first energy storage device is controlled to output the first energy storage power source that conforms to a second preset signal characteristic during a second preset period before the output of the first energy storage device is switched to the AC power source.
15. The power supply method of the energy storage system according to claim 14, comprising:
- when the power source output by the first energy storage device conforms to the second preset signal characteristic, enabling the second energy storage device to use the power source provided by the first energy storage device for charging.
16. The power supply method of the energy storage system according to claim 13, wherein the first preset signal characteristic is different from the second preset signal characteristic.
17. The power supply method of the energy storage system according to claim 13, wherein the first preset signal characteristic comprises a first preset frequency change rule, and the second preset signal characteristic comprises a second preset frequency change rule.
18. The power supply method of the energy storage system according to claim 17, wherein the first preset frequency change rule serves to switch a plurality of frequency values of the power source provided by the first energy storage device according to a first sequence during the first preset period, wherein each of the frequency values is maintained for a corresponding period of time.
19. The power supply method of the energy storage system according to claim 17, wherein the second preset frequency change rule serves to switch a plurality of frequency values of the power source provided by the first energy storage device according to a second sequence during the second preset period, wherein each of the frequency values is maintained for a corresponding period of time.
20. The power supply method of the energy storage system according to claim 12, comprising:
- when it is detected that the first energy storage device stops providing the power source, controlling the second energy storage device to provide the second energy storage power source to the load.
Type: Application
Filed: Jun 1, 2021
Publication Date: Aug 11, 2022
Applicant: Merry Electronics(Shenzhen) Co., Ltd. (ShenZhen)
Inventors: Yung-Hsiang Liu (Taichung), Wei-Kang Liang (Taichung), Yu-Kai Wang (Taichung)
Application Number: 17/335,092