TWI829161B - Energy storage device and method thereof for supplying power - Google Patents

Abstract

An energy storage device and a method thereof for supplying power are provided. Control a power conversion circuit to lower an AC output voltage during a preset period to a preset voltage, control the power conversion circuit to change 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 an output terminal of the power conversion circuit generating a surge current during the surge generation period.

Description

Energy storage device and power supply method thereof

The present invention relates to a power supply device, and in particular, to an energy storage device and a power supply method thereof.

The energy storage system uses an internal battery to store electrical energy. When there is a load demand, the DC power stored in the battery is converted into the AC power required by the load through a power conversion unit (DC/DC converter, DC/AC inverter). In the process of electrical energy 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 continued power consumption will drain the battery energy. 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 inside the energy storage system continues to operate. After a period of time, if the power consumption of the power conversion unit will The battery energy is exhausted and when the user wants to use it next time, the battery will have no power for the user to use.

The present invention provides an energy storage device and a power supply method thereof, which can accurately determine whether the load has been removed from the energy storage device, and automatically shut down the energy storage device when the load is removed from the energy storage device, thereby effectively reducing power loss. .

The energy storage device of the present invention includes a battery module, a power conversion circuit, a sensing circuit and a control circuit. The battery module provides DC voltage. The power conversion circuit is coupled to the battery module, converts the DC voltage into an AC output voltage, and provides the AC output voltage to the output end of the power conversion circuit to power the load. The sensing circuit is coupled to the output end of the power conversion circuit and senses the current and voltage at the output end of the power conversion circuit. The control circuit is coupled to the power conversion circuit and the sensing circuit, controls the power conversion circuit to reduce the AC output voltage during a preset period to a preset voltage, and controls the power conversion circuit to change from outputting the preset voltage to outputting a surge voltage, thereby converting the power supply When the circuit enters the surge generation period, the control circuit determines whether to turn off the energy storage device based on whether the output end of the power conversion circuit generates a surge current during the surge generation period.

In an embodiment of the present invention, the above-mentioned surge current is generated in response to the equivalent capacitance of the load.

In an embodiment of the present invention, the starting time point of the above-mentioned surge generation period corresponds to the time point when the AC output voltage reaches the peak voltage.

In an embodiment of the present invention, the above-mentioned preset period is 1/4 cycle of the AC output voltage.

In an embodiment of the present invention, the voltage value of the above-mentioned preset voltage is close to 0.

In an embodiment of the present invention, the above control circuit determines whether a surge current is generated at the output end of the power conversion circuit based on whether the current sensed by the sensing circuit is greater than the preset current.

In one embodiment of the present invention, the control circuit controls the surge voltage generated by the power conversion circuit to be 1.1 to 1.2 times the normal peak voltage of the AC output voltage during the surge generation period.

In one embodiment of the present invention, the above control circuit controls the power conversion circuit to normally generate the AC output voltage after the surge generation period ends.

The invention also provides a power supply method for an energy storage device. The energy storage device includes a battery module and a power conversion circuit. The power conversion circuit converts the DC voltage provided by the battery module into an AC output voltage to provide the AC output voltage to the power supply. The output end of the conversion circuit supplies power to the load, and the power supply method of the energy storage device includes the following steps. Sensing the current and voltage at the output of the power conversion circuit. The power conversion circuit is controlled to reduce the AC output voltage for a preset period to a preset voltage. The power conversion circuit is controlled to change from outputting a preset voltage to outputting a surge voltage, so that the power conversion circuit enters a surge generation period. Whether to turn off the energy storage device is determined based on whether the output end of the power conversion circuit generates a surge current during the generation of the surge.

In an embodiment of the present invention, the above-mentioned surge current is generated in response to the equivalent capacitance of the load.

In an embodiment of the present invention, the starting time point of the above-mentioned surge generation period corresponds to the time point when the AC output voltage reaches the peak voltage.

In an embodiment of the present invention, the above-mentioned preset period is 1/4 cycle of the AC output voltage.

In an embodiment of the present invention, the voltage value of the above-mentioned preset voltage is close to 0.

In one embodiment of the present invention, the power supply method of the energy storage device includes determining whether a surge current is generated at the output end of the power conversion circuit based on whether the current sensed by the sensing circuit is greater than a preset current.

In one embodiment of the present invention, the surge 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 surge generation period.

In one embodiment of the present invention, the power supply method of the energy storage device includes controlling the power conversion circuit to normally generate the AC output voltage after the surge generation period ends.

Based on the above, embodiments of the present invention can control the power conversion circuit to reduce the AC output voltage during a preset period to a preset voltage, and control the power conversion circuit to change from outputting the preset voltage to outputting a surge voltage, so that the power conversion circuit enters the burst state. During the generation of the wave, and whether to turn off the energy storage device is judged based on whether the output end of the power conversion circuit generates a surge current during the generation of the surge. 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, thereby effectively reducing power loss.

In order to make the above-mentioned features and advantages of the present invention more obvious and easy to understand, embodiments are given below and described in detail with reference to the accompanying drawings.

Figure 1 is a schematic diagram of an energy storage device according to an embodiment of the present invention. Please refer to Figure 1 . The energy storage device 100 may be a power supply device used to power 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 end 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 .

The power conversion circuit 106 can convert the DC voltage provided by the battery module 102 into the AC output voltage VAC to provide the AC output voltage VAC to the output end of the power conversion circuit 106 to power the load 110 . Furthermore, the power conversion circuit 106 may include a DC/DC converter 112 and a DC/AC inverter (DC/AC inverter) 114 as shown in FIG. 1 . The DC/DC converter 112 is coupled to the battery module. Group 102, control circuit 104 and DC/AC inverter 114. The DC/AC inverter 114 is coupled to the control circuit 104 . The DC-DC conversion circuit 112 can convert the DC voltage provided by the battery module 102 into the DC voltage VDC, and provide the DC voltage VDC to the DC-AC inverter 114 . The DC-DC conversion circuit 112 may be, for example, a boost converter, but is not limited thereto. The DC-AC inverter 114 can convert the DC voltage VDC into the AC output voltage VAC. The sensing circuit 108 can sense the AC output voltage VAC and the current I1 at the output end of the power conversion circuit 106, and provide the sensing results to the control circuit 104.

The control circuit 104 can control the power conversion circuit 106 to reduce the AC output voltage VAC during a preset period to a preset voltage, and control the power conversion circuit 106 to change from outputting the preset voltage to outputting a surge voltage, so that the power conversion circuit 106 enters the burst state. During the wave generation, the control circuit 104 determines whether to turn off the energy storage device 100 based on whether the output terminal of the power conversion circuit 106 generates a surge current during the wave generation. For example, when a surge current is generated during a surge, it means that the load 110 is connected to the energy storage device 100, so the control circuit 104 does not need to turn off the energy storage device 100. In the case where no surge current is generated during the surge generation, 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 each circuit in the energy storage device 100. operation, or the energy storage device 100 only uses the power required to restore normal operation to operate necessary circuits, so as to reduce power consumption and save energy loss of the battery module 102 .

Even when the input capacitance of the load 110 is small, the surge current generated during the surge generation can still reflect the presence of the load 110. Therefore, by determining whether the surge current is generated during the passing surge generation, it is possible to accurately determine whether the surge current is generated during the surge generation. Determine whether the load has been removed from the energy storage device, and then automatically shut down the energy storage device 100 when the load is removed from the energy storage device, effectively reducing power loss.

FIG. 2 is a schematic diagram of a DC-AC inverter according to an embodiment of the present invention. The implementation of the DC-AC inverter 114 of the power conversion circuit 106 may be, for example, as shown in FIG. 2 , including a voltage conversion switch circuit 210 and an inductor-capacitor circuit 220. The voltage conversion switch 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 switch circuit 210 may include voltage conversion switches 211~214, the inductor-capacitance circuit 220 may include an inductor L1 and an output capacitor C1, and the voltage conversion switches 211~214 may be configured as a full-bridge circuit, in which the voltage conversion switch 211 and 212 are connected in series between the DC voltage VDC and the reference voltage VR. The voltage conversion switches 213 and 214 are connected in series between the DC voltage VDC and the reference voltage VR. The inductor L1 is coupled to the common contact of the voltage conversion switches 211 and 212. One end of the equivalent capacitance CL of the load 110 and the other end of the equivalent capacitance CL of the load 110 are coupled to the common contact of the voltage conversion switches 213 and 214 .

The voltage conversion switch circuit 210 can receive the DC voltage VDC and is controlled by the control circuit 104 to switch the conduction states of the voltage conversion switches 211 to 214 to generate the AC output voltage VAC on the output capacitor C1. When detecting the load 110, the voltage conversion switches 211~214 are controlled by the control circuit 104 to reduce the AC output voltage VAC to a preset voltage during a preset period, and then enter the surge generation period to output a surge voltage, where The starting time point of the surge generation period corresponds to the time point when the AC output voltage VAC reaches the peak voltage. The peak value of the surge voltage generated by the power conversion circuit 106 during the surge generation period may be, for example, 1.1 of the normal peak voltage of the AC output voltage VAC. ~1.2 times, but not limited to this. After the surge generation period ends, the power conversion circuit 106 normally generates the AC output voltage VAC, that is, generates a sine wave with a fixed amplitude.

For example, as shown in FIG. 3A , the control circuit 104 can control the voltage conversion switches 211 to 214 to reduce the voltage value of the AC output voltage VAC from time point B to time point C (preset period) to close to 0, and at time Point C to time point D (during the surge generation period) are converted into output surge voltage. The preset period is 1/4 cycle of the AC output voltage VAC, but is not limited to this. When the load 110 is coupled to the energy storage device 100, the sensing circuit 108 can sense the surge current at time point C to time point D as shown in FIG. 3A. The control circuit 104 may, for example, determine whether a surge current is generated at the output end of the power conversion circuit based on whether the current sensed by the sensing circuit 108 is greater than a preset current. After the surge generation period ends, the power conversion circuit 106 resumes generating the normal AC output voltage VAC (for example, the AC output voltage VAC from time point D to time point E).

It can be seen from FIG. 3A that although in the period other than time point C to time point D, the sensing circuit 108 cannot sense the current I1 because the equivalent capacitance CL of the load 110 is too small. Making the DC/AC inverter 114 output a surge voltage can generate a surge current that reflects the equivalent capacitance CL, so that the load 110 is judged to be coupled to the energy storage device 100 based on the generation of the surge current.

It is worth noting that in the embodiment of FIG. 3A , the preset period is set to time point B to time point C in the negative half cycle of the AC output voltage VAC. However, this is not limited to other embodiments. In other embodiments, , the start time and end time of the preset period can be set arbitrarily. For example, in the embodiment of FIG. 3B , the preset period can also be set to time point B to time point C in the positive half cycle of the AC output voltage VAC. This can also achieve the purpose of generating a surge current that reflects the equivalent capacitance CL. Effect. In addition, in other embodiments, the preset period is not limited to 1/4 cycle of the AC output voltage VAC, and the designer can set the length of the preset period according to actual needs. In addition, the voltage value of the AC output voltage VAC within the preset period is not limited to being close to 0, and it can also be set to 0 or other voltage values.

In addition, when the load 110 is not coupled to the energy storage device 100, the sensing circuit 108 can be as shown in FIGS. 4A and 4B, and the control circuit 104 also controls the voltage conversion switches 211~214 to change the time point B~time point C ( The voltage value of the AC output voltage VAC during the preset period decreases to close to 0, and turns to the output surge voltage from time point C to time point D (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. Therefore, no surge will occur at the output end of the DC-AC inverter 114 from time point C to time point D. Accordingly, the control circuit 104 can determine that the load 110 is not coupled to the energy storage device 100 and can shut down the energy storage device 100 to reduce power consumption and save energy loss of the battery module 102 .

Figure 5 is a flow chart of a power supply method for an energy storage device according to an embodiment of the present invention. The energy storage device includes a battery module and a power conversion circuit. The power conversion circuit converts the DC voltage provided by the battery module into an AC output voltage to provide the AC output voltage to the output end of the power conversion circuit to power the load. The AC output voltage may be generated, for example, on an output capacitor coupled to an output end of a power conversion circuit. The power conversion circuit may include a DC-DC conversion circuit and a DC-AC inverter. The DC-AC inverter includes an output capacitor. As can be seen from the above embodiments, the power supply method of the power supply device may include the following steps. First, the current and voltage at the output end of the power conversion circuit are sensed (step S502). Further, the AC output voltage can be boosted by controlling the DC to DC conversion circuit, and then controlling the DC to AC inverter conversion. The boosted DC voltage is obtained. Next, the power conversion circuit is controlled to reduce the AC output voltage during a preset period to a preset voltage (step S504), where the preset period may be, for example, 1/4 cycle of the AC output voltage, and the voltage value of the preset voltage may be, for example, close to 0, but it is not limited to this. Then, the power conversion circuit is controlled to switch from outputting the preset voltage to outputting the surge voltage, so that the power conversion circuit enters the surge generation period (step S506). The starting time point of the surge generation period may, for example, correspond to the peak value of the AC output voltage. At the time point of the voltage, the surge voltage generated by the control power conversion circuit during the generation of the surge can be, for example, 1.1 to 1.2 times the normal peak voltage of the AC output voltage, but is not limited to this. Afterwards, it is determined whether to turn off the energy storage device (step S508) based on whether the output end of the power conversion circuit generates a surge current during the surge generation period. The surge current is generated in response to the equivalent capacitance of the load, so it can be determined by determining the surge current. Whether a wave current is generated is used to determine whether the load is coupled to the energy storage device. For example, whether the current sensed by the sensing circuit is greater than the preset current can be used to determine whether a surge current is generated at the output end of the power conversion circuit, and then it is decided whether to turn off the energy storage device. Can be installed. In addition, the power conversion circuit can be controlled to normally generate the AC output voltage after the surge generation period ends.

In summary, embodiments of the present invention can control the power conversion circuit to reduce the AC output voltage during a preset period to a preset voltage, and control the power conversion circuit to change from outputting the preset voltage to outputting a surge voltage, so that the power conversion circuit Entering the surge generation period, and judging whether to turn off the energy storage device depends on whether the output end of the power conversion circuit generates a surge current 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, thereby effectively reducing power loss.

Although the present invention has been disclosed above through embodiments, they are not intended to limit the present invention. Anyone with ordinary knowledge in the technical field may make some modifications and modifications without departing from the spirit and scope of the present invention. Therefore, The protection scope of the present invention shall be determined by the appended patent application scope.

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 and capacitor circuit VAC: AC output voltage VDC: DC voltage I1: current VR: reference voltage CL: equivalent capacitance C1: output capacitor L1: Inductor S502~S508: Power supply method steps of energy storage device

Figure 1 is a schematic diagram of an energy storage device according to an embodiment of the present invention. FIG. 2 is a schematic diagram of a DC-AC inverter according to another embodiment of the present invention. 3A to 4B are schematic diagrams of AC output voltage and current according to embodiments of the present invention. Figure 5 is a flow chart of a power supply method for an energy storage device according to an embodiment of the present invention.

S502~S508: Power supply method steps of energy storage device

Claims (16)

An energy storage device includes: a battery module that provides a DC voltage; a power conversion circuit coupled to the battery module that converts the DC voltage into an AC output voltage to provide the AC output voltage to the power conversion circuit The output end of the circuit supplies power to a load; a sensing circuit, coupled to the output end of the power conversion circuit, senses the current and voltage of the output end of the power conversion circuit; and a control circuit, coupled to the power conversion circuit The circuit and the sensing circuit control the power conversion circuit to reduce the AC output voltage for a preset period to a preset voltage, and control the power conversion circuit to change 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 based on whether the output end of the power conversion circuit generates a surge current during the surge generation period. The energy storage device of claim 1, wherein the surge current is generated in response to the equivalent capacitance of the load. The energy storage device according to 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. The energy storage device as claimed in claim 1, wherein the preset period is 1/4 cycle of the AC output voltage. The energy storage device according to claim 1, wherein the voltage value of the preset voltage is close to 0. The energy storage device of claim 1, wherein the control circuit determines whether the output end of the power conversion circuit generates the surge current based on whether the current sensed by the sensing circuit is greater than a preset current. The energy storage device of claim 1, wherein the control circuit controls the surge voltage generated by the power conversion circuit to be 1.1 to 1.2 times the normal peak voltage of the AC output voltage during the generation of the surge. 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 surge generation period ends. A power supply method for an energy storage device. 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 to provide the AC output. The voltage is supplied to the output end of the power conversion circuit to power a load. The power supply method of the energy storage device includes: sensing the current and voltage of the output end of the power conversion circuit; controlling the power conversion circuit to The AC output voltage is reduced to a preset voltage; 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 according to the power conversion circuit Whether the output terminal generates a surge current during the generation of the surge determines whether to turn off the energy storage device. The power supply method for an energy storage device as described in claim 9, wherein The surge current is generated in response to the equivalent capacitance of the load. The power supply method for an energy storage device as described in 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. The power supply method for an energy storage device as claimed in claim 9, wherein the preset period is 1/4 cycle of the AC output voltage. The power supply method for an energy storage device as claimed in claim 9, wherein the voltage value of the preset voltage is close to 0. The power supply method of the energy storage device as described in claim 9 includes: determining whether the output end of the power conversion circuit generates the surge current based on whether the sensed current is greater than a preset current. The power supply method for an energy storage device as claimed in claim 9, wherein the surge 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 generation of the surge. The power supply method of the energy storage device according to claim 9 includes: controlling the power conversion circuit to normally generate the AC output voltage after the surge generation period ends.

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