Energy storage device and power supply method thereof

Abstract

The application relates to an energy storage device and a power supply method thereof. The energy storage device comprises a battery module, a power conversion circuit, a sensing circuit and a control circuit. The battery module provides a direct current voltage. The power conversion circuit converts the direct current voltage into an alternating output voltage. The sensing circuit senses the current and voltage of the output terminal of the power conversion circuit. The control circuit controls the power conversion circuit to reduce the alternating output voltage to a preset voltage in a preset period, and controls the power conversion circuit to output a surge voltage from the preset voltage, so that the power conversion circuit enters a surge generation period. The control circuit determines whether to close the energy storage device according to whether the output terminal of the power conversion circuit generates a surge current in the surge generation period. The energy storage device can accurately determine whether a load has been removed from the energy storage device, and automatically closes the energy storage device when the load is removed from the energy storage device, thereby effectively reducing power loss.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power supply devices, and in particular to an energy storage device and a power supply method thereof. BACKGROUND

[0002] An energy storage system stores electric energy in an internal battery. When a load is needed, a DC / DC converter or a DC / AC inverter converts the DC power stored in the battery into AC power required by the load. In the process of power conversion, power consumption is inevitable. Even when the energy storage system is not connected to a load, as long as the power conversion unit is working, power consumption will occur, and continuous power consumption will deplete the battery power. For example, when the user has finished using the load and removes the load, but does not turn off the output of the energy storage system, the power conversion unit in the energy storage system continues to operate. After a period of time, if the power consumption of the power conversion unit depletes the battery energy, when the user wants to use it next time, the battery will have no power to supply to the user. SUMMARY

[0003] Therefore, to solve the above problems, the present application provides an energy storage device and a power supply method thereof, which can accurately determine whether a load has been removed from the energy storage device and automatically turn off the energy storage device when the load is removed, thereby effectively reducing power loss.

[0004] An energy storage device, comprising:

[0005] a battery module providing a DC voltage;

[0006] a power conversion circuit coupled to the battery module, converting the DC voltage into an AC output voltage to provide the AC output voltage to an output terminal of the power conversion circuit to supply power to a load;

[0007] a sensing circuit coupled to the output terminal of the power conversion circuit, sensing the current and voltage of the output terminal of the power conversion circuit; and

[0008] a control circuit coupled to the power conversion circuit and the sensing circuit, controlling the power conversion circuit to reduce the AC output voltage to a preset voltage for a preset period, controlling the power conversion circuit to switch from outputting the preset voltage to outputting a surge voltage, so that the power conversion circuit enters a surge generation period, and the control circuit determines whether to turn off the energy storage device according to whether a surge current is generated at the output terminal of the power conversion circuit in the surge generation period.

[0009] In one embodiment, the surge current is generated in response to the equivalent capacitance of the load.

[0010] In one of the embodiments, the starting point of the surge generation period corresponds to the point in time when the AC output voltage reaches the peak voltage.

[0011] In one of the embodiments, the preset period is 1 / 4 of the cycle of the AC output voltage.

[0012] In one of the embodiments, the voltage value of the preset voltage is 0.

[0013] In one of the embodiments, the control circuit determines whether the output terminal of the power conversion circuit generates the surge current according to whether the current sensed by the sensing circuit is greater than a preset current.

[0014] In one of the embodiments, the control circuit controls the surge voltage generated by the power conversion circuit to be 1.1-1.2 times the normal peak voltage of the AC output voltage during the surge generation period.

[0015] In one of the embodiments, the control circuit controls the power conversion circuit to normally generate the AC output voltage after the end of the surge generation period.

[0016] A power supply method of an energy storage device, the energy storage device comprising a battery module and a power conversion circuit, the power conversion circuit converting a direct current voltage provided by the battery module into an alternating current output voltage to supply the alternating current output voltage to an output terminal of the power conversion circuit to power a load, the power supply method of the energy storage device comprising:

[0017] sensing the current and voltage of the output terminal of the power conversion circuit;

[0018] controlling the power conversion circuit to reduce the alternating current output voltage in a preset period to a preset voltage;

[0019] controlling the power conversion circuit to output a surge voltage from the preset voltage, so that the power conversion circuit enters a surge generation period; and

[0020] determining whether to shut down the energy storage device according to whether the output terminal of the power conversion circuit generates a surge current during the surge generation period.

[0021] In one of the embodiments, the surge current is generated in response to the equivalent capacitance of the load.

[0022] In one of the embodiments, the starting point of the surge generation period corresponds to the point in time when the AC output voltage reaches the peak voltage.

[0023] In one of the embodiments, the preset period is 1 / 4 of a cycle of the AC output voltage.

[0024] In one of the embodiments, the preset voltage is 0.

[0025] In one of the embodiments, whether the output terminal of the power conversion circuit generates the surge current is determined according to whether the current of the output terminal of the power conversion circuit is greater than a preset current.

[0026] In one of the embodiments, the surge voltage generated by the power conversion circuit during the surge generation period is controlled to be 1.1-1.2 times of the normal peak voltage of the AC output voltage.

[0027] In one of the embodiments, the power conversion circuit is controlled to normally generate the AC output voltage after the end of the surge generation period.

[0028] The above energy storage device and the power supply method thereof provide a DC voltage by a battery module; a power conversion circuit coupled to the battery module converts the DC voltage into an AC output voltage to provide the AC output voltage to an output terminal of the power conversion circuit to supply power to a load; a sensing circuit coupled to the output terminal of the power conversion circuit senses the current and voltage of the output terminal of the power conversion circuit; and a control circuit coupled to the power conversion circuit and the sensing circuit controls the power conversion circuit to reduce the AC output voltage to a preset voltage for a preset period, controls the power conversion circuit to output a surge voltage from the preset voltage, and makes the power conversion circuit enter a surge generation period, and the control circuit determines whether to shut down the energy storage device according to whether the output terminal of the power conversion circuit generates a surge current during the surge generation period; thus, it can be accurately determined whether the load has been removed from the energy storage device, and the energy storage device can be automatically shut down when the load is removed from the energy storage device, thereby effectively reducing power loss. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0030] Figure 1 The structural schematic block diagram of the energy storage device in one embodiment;

[0031] Figure 2 The structural schematic diagram of the DC-AC inverter in one embodiment;

[0032] Figures 3A-4B Fig. 2 is a graph showing the variation of AC output voltage and current in one embodiment;

[0033] Figure 5 Fig. 4 is a flowchart showing the power supply method of the energy storage device in one embodiment.

[0034] BRIEF DESCRIPTION OF DRAWINGS

[0035] BRIEF DESCRIPTION OF DRAWINGS 100: energy storage device, 102: battery module, 104: control circuit, 106: power conversion circuit, 108: sensing circuit, 110: load, 112: DC / DC conversion circuit, 114: DC / AC inverter, 210: voltage conversion switch circuit, 211-214: voltage conversion switch, 220: inductor-capacitor circuit, VAC: AC output voltage, VDC: DC voltage, I1: current, VR: reference voltage, CL: equivalent capacitance, C1: output capacitance, L1: inductor, S502-S508: power supply method steps of the energy storage device. DETAILED DESCRIPTION

[0036] For the purpose of the present application, the following description will be made with reference to the accompanying drawings. In the drawings, embodiments of the present application are shown. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0038] As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising", or "includes" and / or "including" when used in this specification, specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

[0039] Figure 1 Fig. 1 is a schematic diagram of an energy storage device according to an embodiment of the present application. Please refer to Figure 1The energy storage device 100 can be a power supply device for supplying power to the load 110. The energy storage device 100 includes a battery module 102, a control circuit 104, a power conversion circuit 106, and a sensing circuit 108; the battery module 102 is coupled to the power conversion circuit 106, the power conversion circuit 106 is coupled to the control circuit 104, and the output terminal of the power conversion circuit 106 is coupled to the sensing circuit 108 and the load 110 external to the energy storage device 100; the control circuit 104 is coupled to the sensing circuit 108.

[0040] The power conversion circuit 106 converts the DC voltage provided by the battery module 102 into an AC output voltage VAC, which is then supplied to the output of the power conversion circuit 106 to power the load 110. Furthermore, the power conversion circuit 106 can be configured as follows: Figure 1 As shown, the system includes a DC / DC converter 112 and a DC / AC inverter 114. The DC / DC converter 112 is coupled to the battery module 102, the control circuit 104, and the DC / AC inverter 114. The DC / AC inverter 114 is coupled to the control circuit 104. The DC / DC converter 112 converts the DC voltage provided by the battery module 102 into a DC voltage VDC and provides the DC voltage VDC to the DC / AC inverter 114. The DC / DC converter 112 may be, for example, a boost converter, but is not limited thereto. The DC / AC inverter 114 converts the DC voltage VDC into an AC output voltage VAC. The sensing circuit 108 senses the AC output voltage VAC and the current I1 at the output of the power conversion circuit 106 and provides the sensing results to the control circuit 104.

[0041] The control circuit 104 controls the power conversion circuit 106 to reduce the AC output voltage VAC during a preset period to a preset voltage, and controls the power conversion circuit 106 to switch from outputting the preset voltage to outputting a surge voltage, thus putting the power conversion circuit 106 into a surge generation period. The control circuit 104 determines whether to shut down the energy storage device 100 based on whether a surge current is generated at the output terminal of the power conversion circuit 106 during the surge generation period. For example, if a surge current is generated during the surge generation period, it means that the load 110 is not connected to the energy storage device 100, so the control circuit 104 does not need to shut down the energy storage device 100. If no surge current is generated during the surge generation period, it means that the load 110 has been removed from the energy storage device 100, and the control circuit 104 can shut down the energy storage device 100. For example, it can stop the operation of each circuit in the energy storage device 100, or make the energy storage device 100 only operate the necessary circuits with the power required to restore normal operation, so as to reduce power consumption and save energy loss of the battery module 102.

[0042] Since the inrush current generated during the inrush generation period can reflect the presence of the load 110 even when the input capacitance of the load 110 is small, the presence or absence of the load can be accurately determined by determining whether the inrush current is generated during the inrush generation period, and the power storage device 100 can be automatically turned off when the load is removed from the power storage device, thereby effectively reducing power loss.

[0043] Figure 2 is a schematic diagram of a DC-to-AC inverter according to an embodiment of the present application. The DC-to-AC inverter 114 of the power conversion circuit 106 can include, for example, a voltage conversion switching circuit 210 and an inductor-capacitor circuit 220 as shown in Figure 2 The voltage conversion switching circuit 210 is coupled to the inductor-capacitor circuit 220. The inductor-capacitor circuit 220 is coupled to the equivalent capacitance CL of the load 110. In detail, the voltage conversion switching circuit 210 can include voltage conversion switches 211 to 214, and the inductor-capacitor circuit 220 can include an inductor LI and an output capacitor CI. The voltage conversion switches 211 to 214 can be configured as a full-bridge circuit, in which the voltage conversion switches 211 and 212 are connected in series between the DC voltage VDC and a reference voltage VR, and the voltage conversion switches 213 and 214 are connected in series between the DC voltage VDC and the reference voltage VR. The inductor LI is coupled between the common node of the voltage conversion switches 211 and 212 and one end of the equivalent capacitance CL of the load 110, and the other end of the equivalent capacitance CL of the load 110 is coupled to the common node of the voltage conversion switches 213 and 214.

[0044] The voltage conversion switching circuit 210 can receive the DC voltage VDC and generate an AC output voltage VAC on the output capacitor CI by switching the conduction states of the voltage conversion switches 211 to 214 under the control of the control circuit 104. In detecting the load 110, the voltage conversion switches 211 to 214 are controlled by the control circuit 104 to reduce the AC output voltage VAC to a predetermined voltage for a predetermined period, and then enter an inrush generation period to output an inrush voltage. The start point of the inrush generation period corresponds to the point in time at which the AC output voltage VAC reaches a peak voltage. The peak value of the inrush voltage generated by the power conversion circuit 106 during the inrush generation period can be, for example, 1.1 to 1.2 times the normal peak voltage of the AC output voltage VAC, but is not limited thereto. After the end of the inrush generation period, the power conversion circuit 106 normally generates the AC output voltage VAC, i.e., a sine wave having a fixed amplitude.

[0045] For example, as shown in Figure 3AAs shown, the control circuit 104 can control the voltage conversion switches 211-214 to reduce the voltage value of the AC output voltage VAC to near 0 during the time point B to the time point C (a preset period), and to output a surge voltage during the time point C to the time point D (a surge generation period). The preset period is 1 / 4 of the period of the AC output voltage VAC, but is not limited thereto. In the case where the load 110 is coupled to the energy storage device 100, the sensing circuit 108 can sense the current I1 flowing through the load 110 during the time point C to the time point D. Figure 3A As shown, the control circuit 104 can control the voltage conversion switches 211-214 to reduce the voltage value of the AC output voltage VAC to near 0 during the time point B to the time point C (a preset period), and to output a surge voltage during the time point C to the time point D (a surge generation period). The preset period is 1 / 4 of the period of the AC output voltage VAC, but is not limited thereto. In the case where the load 110 is coupled to the energy storage device 100, the sensing circuit 108 can sense the current I1 flowing through the load 110 during the time point C to the time point D.

[0046] As shown, the control circuit 104 can control the voltage conversion switches 211-214 to reduce the voltage value of the AC output voltage VAC to near 0 during the time point B to the time point C (a preset period), and to output a surge voltage during the time point C to the time point D (a surge generation period). The preset period is 1 / 4 of the period of the AC output voltage VAC, but is not limited thereto. In the case where the load 110 is coupled to the energy storage device 100, the sensing circuit 108 can sense the current I1 flowing through the load 110 during the time point C to the time point D. Figure 3A As shown, the control circuit 104 can control the voltage conversion switches 211-214 to reduce the voltage value of the AC output voltage VAC to near 0 during the time point B to the time point C (a preset period), and to output a surge voltage during the time point C to the time point D (a surge generation period). The preset period is 1 / 4 of the period of the AC output voltage VAC, but is not limited thereto. In the case where the load 110 is coupled to the energy storage device 100, the sensing circuit 108 can sense the current I1 flowing through the load 110 during the time point C to the time point D.

[0047] It is noted that, Figure 3A The preset period is set to the time point B to the time point C in the negative half cycle of the AC output voltage VAC in the embodiment, but is not limited thereto in other embodiments. In other embodiments, the start time and the end time of the preset period can be set arbitrarily. For example, in Figure 3B The preset period can also be set to the time point B to the time point C in the positive half cycle of the AC output voltage VAC in the embodiment, and the same effect of generating the surge current reacting to the equivalent capacitance CL can be achieved. In addition, the preset period is not limited to 1 / 4 of the period of the AC output voltage VAC in other embodiments, and the designer can set the time length of the preset period according to actual needs. In addition, the voltage value of the AC output voltage VAC in the preset period is not limited to near 0, and can also be set to 0 or other voltage values.

[0048] In addition, in the case where the load 110 is not coupled to the energy storage device 100, the sensing circuit 108 can sense the current I1 flowing through the load 110 during the time point C to the time point D. Figure 4A In addition, in the case where the load 110 is not coupled to the energy storage device 100, the sensing circuit 108 can sense the current I1 flowing through the load 110 during the time point C to the time point D. 4BAs shown, the control circuit 104 also controls the voltage conversion switches 211-214 to reduce the voltage value of the AC output voltage VAC from time point B to time point C (a preset period) to near 0, and to output a surge voltage from time point C to time point D (a surge generation period). However, since the load 110 is not coupled to the energy storage device 100, the output end of the DC-AC inverter 114 is in an open circuit state, and thus no surge current is generated at the output end of the DC-AC inverter 114 from time point C to time point D. Therefore, the control circuit 104 can determine that the load 110 is not coupled to the energy storage device 100, and can turn off the energy storage device 100 to reduce power consumption and save the energy loss of the battery module 102.

[0049] Figure 5 A flowchart of a power supply method of an energy storage device according to an embodiment of the present application is shown. The energy storage device includes a battery module and a power conversion circuit. The power conversion circuit converts a DC voltage provided by the battery module into an AC output voltage, and provides the AC output voltage to an output end of the power conversion circuit to supply power to a load. The AC output voltage can be generated on an output capacitor coupled to the output end of the power conversion circuit, for example. The power conversion circuit can include a DC-DC conversion circuit and a DC-AC inverter, and the DC-AC inverter includes an output capacitor. As shown in the above embodiment, the power supply method of the power supply device can include the following steps.

[0050] First, the current and voltage of the output terminal of the power conversion circuit are sensed (step S502). Further, the AC output voltage can be obtained by, for example, first boosting a DC voltage via a control DC-DC conversion circuit, and then controlling a DC-AC inverter to convert the boosted DC voltage. Next, the power conversion circuit is controlled to reduce the AC output voltage to a preset voltage during a preset period (step S504). The preset period can be, for example, 1 / 4 of a cycle of the AC output voltage, and the preset voltage can be, for example, close to 0, but is not limited thereto. Then, the power conversion circuit is controlled to change from outputting the preset voltage to outputting a surge voltage, so that the power conversion circuit enters a surge generation period (step S506). The starting time point of the surge generation period can correspond to the time point at which the AC output voltage reaches a peak voltage, for example. The surge voltage generated by the power conversion circuit during the surge generation period can be, for example, 1.1-1.2 times the normal peak voltage of the AC output voltage, but is not limited thereto. Subsequently, it is determined whether to turn off the energy storage device according to whether a surge current is generated at the output terminal of the power conversion circuit during the surge generation period (step S508). The surge current is generated in response to the equivalent capacitance of the load, so that whether the load is coupled to the energy storage device can be determined by determining whether the surge current is generated. For example, whether the surge current is generated at the output terminal of the power conversion circuit can be determined according to whether the current sensed by the sensing circuit is greater than a preset current, so as to determine whether to turn off the energy storage device. In addition, the power conversion circuit can be controlled to normally generate the AC output voltage after the end of the surge generation period.

[0051] It should be understood that, although Figure 5 the steps in the flowcharts of the above embodiments are displayed in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, the execution of these steps is not strictly limited in sequence, and these steps can be executed in other sequences. Moreover, Figure 5 at least part of the steps in the above embodiments can include multiple sub-steps or multiple stages, which are not necessarily executed at the same time, but can be executed at different times. The execution sequence of these sub-steps or stages is not necessarily sequential, but can be executed in rotation or alternation with at least part of other steps or sub-steps or stages of other steps. It should be noted that the above different embodiments can be combined with each other.

[0052] In summary, the embodiments of the present application can control the power conversion circuit to reduce the AC output voltage to a preset voltage during a preset period, control the power conversion circuit to switch from outputting the preset voltage to outputting a surge voltage, so that the power conversion circuit enters a surge generation period, and determine whether to turn off the energy storage device according to whether a surge current is generated at the output end of the power conversion circuit during the surge generation period. In this way, it can be accurately determined whether the load has been removed from the energy storage device, and the energy storage device can be automatically turned off when the load is removed from the energy storage device, so that power loss can be effectively reduced.

[0053] The technical features of the above-described embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, but as long as the combinations of the technical features do not contradict each other, they should be considered within the scope of the present disclosure.

[0054] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent application scope. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the patent protection scope of the present application should be subject to the appended claims.

Claims

1. An energy storage device, characterized by, The application includes: a battery module providing a DC voltage; a power conversion circuit coupled to the battery module, converting the DC voltage to an AC output voltage to provide the AC output voltage to an output terminal of the power conversion circuit to power a load; a sensing circuit coupled to the output terminal of the power conversion circuit, sensing current and voltage of the output terminal of the power conversion circuit; and a control circuit coupled to the power conversion circuit and the sensing circuit, controlling the power conversion circuit to reduce the AC output voltage to a preset voltage for a preset period, controlling the power conversion circuit to output a surge voltage from outputting the preset voltage, so that the power conversion circuit enters a surge generation period, and the control circuit determines whether to shut down the energy storage device according to whether a surge current is generated at the output terminal of the power conversion circuit during the surge generation period.

2. The energy storage device of claim 1, wherein, The surge current is generated in response to the equivalent capacitance of the load.

3. The energy storage device of claim 1, wherein, The starting time point of the surge generation period corresponds to the time point when the AC output voltage reaches the peak voltage.

4. The energy storage device of claim 1, wherein, The preset period is 1 / 4 of the cycle of the AC output voltage.

5. The energy storage device of claim 1, wherein, The voltage value of the preset voltage is 0.

6. The energy storage device of claim 1, wherein, The control circuit determines whether the surge current is generated at the output terminal of the power conversion circuit according to whether the current sensed by the sensing circuit is greater than a preset current.

7. The energy storage device of claim 1, wherein, The control circuit controls the surge voltage generated by the power conversion circuit during the surge generation period to be 1.1-1.2 times the normal peak voltage of the AC output voltage.

8. The energy storage device of claim 1, wherein, The control circuit controls the power conversion circuit to normally generate the AC output voltage after the end of the surge generation period.

9. A power supply method of an energy storage device, the energy storage device including a battery module and a power conversion circuit, the power conversion circuit converting a DC voltage provided by the battery module to an AC output voltage to provide the AC output voltage to an output terminal of the power conversion circuit to power a load, the power supply method of the energy storage device including: sensing current and voltage of the output terminal of the power conversion circuit; controlling the power conversion circuit to reduce the AC output voltage to a preset voltage for a preset period; controlling the power conversion circuit to output a surge voltage from outputting the preset voltage, so that the power conversion circuit enters a surge generation period; and determining whether to shut down the energy storage device according to whether a surge current is generated at the output terminal of the power conversion circuit during the surge generation period.

10. The power supply method according to claim 9, wherein The surge current is generated in response to the equivalent capacitance of the load.

11. The power supply method according to claim 9, wherein The starting time point of the surge generation period corresponds to the time point when the AC output voltage reaches the peak voltage.

12. The power supply method of claim 9, wherein, The preset period is 1 / 4 of the cycle of the AC output voltage.

13. The power supply method of claim 9, wherein The voltage value of the preset voltage is 0.

14. The power supply method of claim 9, wherein The control circuit determines whether the surge current is generated at the output terminal of the power conversion circuit according to whether the current sensed by the sensing circuit is greater than a preset current.

15. The power supply method of claim 9, wherein, The inrush voltage generated by the power conversion circuit is controlled to be 1.1 to 1.2 times the normal peak voltage of the AC output voltage during the inrush generation period.

16. The power supply method of claim 9, wherein The power conversion circuit is controlled to normally generate the AC output voltage after the end of the inrush generation period.

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