Current sampling system and energy storage device

Abstract

The utility model discloses a current sampling system and an energy storage device. The current sampling system comprises a control unit, a plurality of current sampling circuits and a plurality of signal processing circuits, wherein each current sampling circuit is provided with a sampling resistor and a switching device; a connecting end after the first ends of the current sampling circuits are connected is connected with the negative electrode end of the storage battery, and a connecting end after the second ends of the current sampling circuits are connected is connected with an external power device; the signal receiving end of each signal processing circuit is connected with the sampling resistor in the current sampling circuit corresponding to the signal processing circuit, and is used for collecting differential voltage at the two ends of the sampling resistor and sending the differential voltage to the control unit; the control unit is used for receiving the differential voltage and determining the battery current of the storage battery based on the differential voltage. According to the technical scheme disclosed by the utility model, the sampling precision of the battery current of the storage battery can be improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to current detection technical field especially is related to a current sampling system and energy storage device. BACKGROUND

[0002] With the rapid development of new energy technology and energy storage technology, energy storage devices are widely used in power systems. In the actual application process of energy storage devices, monitoring the remaining capacity (SOC) of the battery in the energy storage device is a prerequisite for effective use of the energy storage device. Currently, when monitoring the remaining capacity of the battery, the ampere-hour integration method is often used to calculate the remaining capacity of the battery by integrating the battery current over time, so the battery current of the battery must be sampled in real time to determine the battery current of the battery.

[0003] Currently, the way to sample the battery current of the battery is to connect a sampling resistor in series between the negative terminal of the battery and the power device (such as a DC / DC converter) in the energy storage device for connecting to the battery, to collect the differential voltage across the sampling resistor, and to process the differential voltage based on a computer device such as a microcontroller to obtain the battery current flowing through the sampling resistor to determine the battery current of the battery, thereby completing the sampling of the battery current.

[0004] However, in an energy storage device connected with a solar panel and other new energy power generation equipment, the current value of the battery current for charging and discharging the battery varies greatly, and its current value range is often as high as plus or minus 200A. For example, when the solar panel is fully loaded during the day, the battery is in a full load state, and the battery current of the battery is large, which can generate a large differential voltage at the sampling resistor, so the sampling of the battery current is relatively accurate. But at night, the battery current of the battery is small, and based on the same sampling resistor for current collection, it will result in a low differential voltage at the sampling resistor, combined with circuit parameter drift and other factors, resulting in a large sampling error when sampling small current, which cannot guarantee the sampling accuracy of the battery current of the battery. SUMMARY

[0005] Therefore, the utility model provides a current sampling system and energy storage device, which mainly aims to solve the technical problem of low sampling accuracy of the battery current of the battery.

[0006] To achieve the above object, the utility model provides a current sampling system for sampling battery current of battery, the current sampling system includes control unit, a plurality of current sampling circuits and a plurality of signal processing circuits, wherein, the current sampling circuit has sampling resistance and switching device, the switching device is used to make the current sampling circuit be in pass state or open circuit state, the resistance of sampling resistance in each current sampling circuit is different, the current sampling circuit corresponds with the signal processing circuit one by one;

[0007] The connecting end after the first end of each current sampling circuit is connected with the negative terminal of the battery, and the connecting end after the second end of each current sampling circuit is connected with an external power device, so that the sampling resistance in each current sampling circuit is connected in series between the negative terminal of the battery and the power device.

[0008] The signal receiving end of each signal processing circuit is connected with the sampling resistance in the current sampling circuit corresponding to the signal processing circuit, for collecting the differential voltage across the sampling resistance and sending the differential voltage to the control unit.

[0009] The control unit is used for receiving the differential voltage and determining the battery current of the battery based on the differential voltage.

[0010] In an embodiment of the utility model, the sampling resistance and the switching device in the current sampling circuit are connected in series between the first end of the current sampling circuit and the second end of the current sampling circuit, when the switching device is turned on, the negative terminal of the battery and the power device are connected through the current sampling circuit for current interaction, when the switching device is turned off, the negative terminal of the battery and the power device are disconnected.

[0011] In an embodiment of the utility model, the control end and the remote end of the switching device are connected with a host computer, for being controlled to be in the turned-on or turned-off state.

[0012] In an embodiment of the utility model, the switching device includes a triode and a diode, the connecting end after the cathode end of the diode is connected with the collector end of the triode is connected with the first end of the sampling resistance, the connecting end after the anode end of the diode is connected with the emitter end of the triode is used as the second end of the current sampling circuit, and the base end of the triode is connected with the host computer, for being controlled to make the triode be in the turned-on or turned-off state.

[0013] In an embodiment of the utility model, the signal processing circuit includes isolation chip and operational amplifier circuit, the first collection end of isolation chip is connected with the first end of sampling resistance in current sampling circuit, the second collection end of isolation chip is connected with the second end of sampling resistance in current sampling circuit, the first output end and the second output end of isolation chip are connected with the first input end and the second input end of operational amplifier circuit respectively, be used for collecting the differential voltage at sampling resistance, and the differential voltage is sent to operational amplifier circuit, operational amplifier circuit is used for signal amplification processing to the differential voltage, obtains the differential voltage after amplification processing, and the differential voltage after amplification processing is sent to control unit.

[0014] In an embodiment of the utility model, the operational amplifier circuit includes an operational amplifier, a first resistor, a second resistor, a third resistor, and a fourth resistor; the first end of the first resistor is connected with the first output end of the isolation chip, the second end of the first resistor is connected with the non-inverting input end of the operational amplifier, the first end of the second resistor is connected with the second output end of the isolation chip, and the second end of the second resistor is connected with the inverting input end of the operational amplifier; the first end of the third resistor is connected with the inverting input end of the operational amplifier, and the second end of the third resistor is connected with the output end of the operational amplifier; the first end of the fourth resistor is connected with the output end of the operational amplifier, and the second end of the fourth resistor is connected with the signal input end of the control unit.

[0015] In an embodiment of the utility model, the current sampling system further includes an acousto-optic alarm unit; the alarm control end of the control unit is connected with the control end of the acousto-optic alarm unit, for controlling the acousto-optic alarm unit to send an acousto-optic alarm signal.

[0016] In an embodiment of the utility model, the control unit is provided with a man-machine interaction interface; the signal interaction end of the control unit is connected with the control end of the man-machine interaction interface.

[0017] In addition, to achieve the above object, the utility model also provides a kind of energy storage device, the energy storage device includes DC / DC converter, inverter and the current sampling system as described above;

[0018] The first positive electrode access end of the DC / DC converter is connected with the positive electrode end of the storage battery, and the first negative electrode access end of the DC / DC converter is connected with the connection end after the second end of each current sampling circuit is connected.

[0019] The second positive access end of the DC / DC converter is connected with the positive access end of the inverter, the second negative access end of the DC / DC converter is connected with the negative access end of the inverter, and the alternating current end of the inverter is connected with external power equipment.

[0020] In an embodiment of the utility model, the energy storage device further includes a maximum power point tracking control solar controller and a first capacitor; the first positive access end of the maximum power point tracking control solar controller is connected with the positive end of external photovoltaic power generation equipment, the first negative access end of the maximum power point tracking control solar controller is connected with the negative end of the photovoltaic power generation equipment; the second positive access end of the maximum power point tracking control solar controller is connected with the second positive access end of the DC / DC converter, the second negative access end of the maximum power point tracking control solar controller is connected with the second negative access end of the DC / DC converter; the first end of the first capacitor is connected with the second positive access end of the DC / DC converter and the second positive access end of the maximum power point tracking control solar controller respectively, and the second end of the first capacitor is connected with the second negative access end of the DC / DC converter.

[0021] The current sampling system and the energy storage device can make the battery current between the negative end of the storage battery and the power device interact through the current sampling circuit. Further, if it is determined that the battery current of the storage battery is small, for example, at night, it can be determined that the battery current of the storage battery is small, the current sampling circuit with the sampling resistor with a high resistance value can be turned on, and the other current sampling circuits can be turned off, so that the battery current can interact through the sampling resistor with a high resistance value, and the small battery current can also form a differential voltage with a high value on the sampling resistor. Further, the signal processing circuit corresponding to the turned-on current sampling circuit acquires the differential voltage on the sampling resistor and sends the differential voltage to the control unit, so that the control unit can sample the current battery current of the storage battery.

[0022] On the contrary, if it is determined that the battery current of the storage battery is high, for example, it can be determined that the battery current of the storage battery is high during the day, the current sampling circuit with the sampling resistance with a smaller resistance value can be turned on, and other current sampling circuits are turned off, so that the battery current can pass through the sampling resistance with a smaller resistance value for current interaction; further, the signal processing circuit corresponding to the turned-on current sampling circuit acquires the differential voltage on the sampling resistance, and sends the differential voltage to the control unit, so that the control unit completes sampling of the current battery current of the storage battery. The technical scheme provided in the application can sample the battery current of the storage battery based on the sampling resistances with different resistance values, realize segmented sampling of the battery current, ensure that the battery current of any intensity can be accurately sampled by the current sampling system, and improve the sampling accuracy of the battery current of the storage battery.

[0023] The above description is only a summary of the technical scheme of the utility model, in order to more clearly understand the technical means of the utility model, which can be implemented according to the content of the specification, and in order to make the above and other purposes, characteristics and advantages of the utility model more obvious and easy to understand, the specific implementation of the utility model is described below. BRIEF DESCRIPTION OF DRAWINGS

[0024] The drawings described herein are used to provide further understanding of the utility model, and constitute a part of the utility model, the schematic embodiment of the utility model and its description are used to explain the utility model, and do not constitute improper limitation on the utility model. In the drawings:

[0025] Figure 1 A structure schematic diagram of a current sampling system provided by an embodiment of the utility model is shown;

[0026] Figure 2 A structure schematic diagram of another current sampling system provided by an embodiment of the utility model is shown;

[0027] Figure 3 A structure schematic diagram of a signal processing circuit provided by an embodiment of the utility model is shown;

[0028] Figure 4 A structure schematic diagram of an energy storage device provided by an embodiment of the utility model is shown. DETAILED DESCRIPTION

[0029] In the following, the utility model will be described in detail with reference to the drawings and in combination with embodiments. It should be noted that the embodiments in the utility model and the features in the embodiments can be combined with each other without conflict.

[0030] For further illustrating the technical means and effects taken by the utility model to achieve the predetermined utility model purposes, the following will combine with the drawings and preferred embodiments to specifically explain the specific implementation, structure, features and effects of the utility model application. In the following description, different "an embodiment" or "embodiments" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0031] The current sampling system and energy storage device according to some embodiments of the utility model are described below. Figures 1 to 4 The current sampling system and energy storage device according to some embodiments of the utility model are described below.

[0032] As Figure 1 shown, one embodiment of the utility model provides a current sampling system for sampling the battery current of a battery, wherein the current sampling system comprises a control unit 100, a plurality of current sampling circuits 200 and a plurality of signal processing circuits 300, wherein the current sampling circuit 200 has a sampling resistor (not shown in the figure) and a switching device (not shown in the figure), the switching device is used to make the current sampling circuit 200 in the on state or off state, the resistance of the sampling resistor in each current sampling circuit 200 is different, and the current sampling circuit 200 corresponds to the signal processing circuit 300 one by one; here, each current sampling circuit 200 corresponds to one signal processing circuit 300. Further, the control unit 100 can be a single-chip microcomputer, a digital signal processor and a microcontroller unit (MCU) and other computer devices, and the control unit 100 is provided with a computer program in the prior art for determining the current value based on the differential voltage. Here, the switching device can be an insulate-gate bipolar transistor (IGBT), a metal-oxide-semiconductor field-effect transistor (MOSFET) and other semiconductor devices, or a relay, a contactor and other devices that can be controlled to be on or off, and combinations of the above devices, which are not limited in the embodiment and are applicable to the embodiment.

[0033] Specifically, the first end of each current sampling circuit 200 is connected to the negative terminal BAT- of the battery 400, and the second end of each current sampling circuit 200 is connected to the external power device 500, so that the sampling resistor in each current sampling circuit 200 is connected in series between the negative terminal BAT- of the battery 400 and the power device 500. Here, the power device 500 can be a power device in a DC / DC converter or other energy storage device, used for power interaction with the battery 400. Further, the power device 500 can also be connected to an inverter to obtain direct current from the battery 400 and send the direct current to the inverter device 600, so that the inverter device 600 converts the direct current into alternating current and connects the alternating current to an external power system (not shown in the figure).

[0034] Further, the switching device in a certain current sampling circuit 200 can be turned off to prevent current transmission between the negative terminal BAT- of the battery 400 and the power device 500 through the current sampling circuit 200, so that the battery current between the negative terminal BAT- of the battery 400 and the power device 500 cannot flow through the sampling resistor in the current sampling circuit 200. Conversely, the switching device in a certain current sampling circuit 200 can be turned on to allow current transmission between the negative terminal BAT- of the battery 400 and the power device 500 through the current sampling circuit 200, so that the battery current between the negative terminal BAT- of the battery 400 and the power device 500 can flow through the sampling resistor in the current sampling circuit 200.

[0035] Further, the signal receiving end of each signal processing circuit 300 is connected to the sampling resistor in the current sampling circuit 200 corresponding to the signal processing circuit 300, for collecting the differential voltage across the sampling resistor and sending the differential voltage to the control unit 100. Specifically, each signal processing circuit 300 corresponds to a current sampling circuit 200, for collecting the voltage difference across the sampling resistor in the current sampling circuit 200 and determining the voltage difference as the differential voltage. Here, if a certain current sampling circuit 200 is turned on, the sampling resistor in the turned-on current sampling circuit 200 will generate a differential voltage due to the battery current, and the signal processing circuit 300 can collect the differential voltage and send it to the control unit 100. Conversely, if a certain current sampling circuit 200 is turned off, the sampling resistor in the turned-off current sampling circuit 200 will not generate a differential voltage, so that the signal processing circuit 300 corresponding to the current sampling circuit 200 cannot collect the differential voltage.

[0036] Further, the control unit 100 is configured to receive the differential voltage and determine the battery current of the battery based on the differential voltage. Specifically, if a certain signal processing circuit 300 can collect the differential voltage from the sampling resistor corresponding to the signal processing circuit 300, the control unit 100 can obtain the differential voltage and determine the battery current of the battery 400 based on the differential voltage according to the prior art.

[0037] The current sampling system according to the embodiments of the present application can connect a plurality of current sampling circuits with sampling resistors between the negative terminal of the battery and the power device, so that the battery current between the negative terminal of the battery and the power device can be exchanged through the current sampling circuit. Further, if it is determined that the battery current of the battery is small, for example, at night, the battery current of the battery can be determined to be small, the current sampling circuit with the sampling resistor with a higher resistance value can be turned on, and the other current sampling circuits can be turned off, so that the battery current can be exchanged through the sampling resistor with a higher resistance value, and the small battery current can also form a differential voltage with a higher value on the sampling resistor. Further, the signal processing circuit corresponding to the turned-on current sampling circuit can obtain the differential voltage on the sampling resistor and send the differential voltage to the control unit, so that the control unit can complete the sampling of the battery current of the current battery. On the contrary, if it is determined that the battery current of the battery is high, for example, during the day, the battery current of the battery can be determined to be high, the current sampling circuit with the sampling resistor with a smaller resistance value can be turned on, and the other current sampling circuits can be turned off, so that the battery current can be exchanged through the sampling resistor with a smaller resistance value. Further, the signal processing circuit corresponding to the turned-on current sampling circuit can obtain the differential voltage on the sampling resistor and send the differential voltage to the control unit, so that the control unit can complete the sampling of the battery current of the current battery. The technical scheme provided in the present application can sample the battery current of the battery based on the sampling resistors with different resistance values, ensure that any intensity of the battery current can be accurately collected by the current sampling system, and improve the sampling accuracy of the battery current of the battery.

[0038] In an embodiment of the present application, as shown in Figure 2As shown, the sampling resistor 210 and the switching device 220 in the current sampling circuit 200 are connected in series between the first end of the current sampling circuit 200 and the second end of the current sampling circuit 200, when the switching device 220 is turned on, the negative terminal BAT- of the battery 400 and the power device 500 interact with each other through the current sampling circuit 200; when the switching device 220 is turned off, the negative terminal BAT- of the battery 400 and the power device 500 are disconnected, and cannot interact with each other through the current sampling circuit 200. Here, the switching device 220 can be controlled to be in the on state or the off state, and the relevant staff can operate the switching device 220 in each current sampling circuit 200 to control the on-off state of each current sampling circuit 200.

[0039] The embodiments provided in the application can control the switching device in each current sampling circuit to quickly change the on-off state of each current sampling circuit, thereby improving the working efficiency of the current sampling system.

[0040] In an embodiment of the present application, the control end of the switching device is connected with the upper computer of the remote end, and is used to be controlled to be in the on state or the off state. Here, the upper computer can be a computer device used by the relevant staff, and the relevant staff can control the switching device in each current sampling circuit at the upper computer. In addition, the control end of the switching device can also be connected with the control unit, so that the control unit can adjust the on-off state of the switching device. The embodiments provided in the application can remotely control the switching device in each current sampling circuit, thereby improving the operation convenience of the current sampling system.

[0041] In an embodiment of the present application, as shown in the figure, Figure 2 The switching device 220 includes a triode 221 and a diode 222. Here, the triode 221 can be an NPN triode.

[0042] Specifically, the connection end after the cathode end of the diode 222 is connected with the collector end of the triode 221 is connected with the first end of the sampling resistor 210, and the connection end after the anode end of the diode 22 is connected with the emitter end of the triode 221 is connected with the power device as the second end of the current sampling circuit 200.

[0043] Further, the base end of the triode 221 is connected with the host computer (not shown in the figure) for controlled turning on or turning off of the triode 221. Specifically, the host computer can send a high-level signal or a low-level signal to the base of the triode 221 to control the turning on or turning off of the triode 221. When the high-level signal is received at the base end of the triode 221, the switch device 220 in which the triode 221 is located is turned on. Conversely, when the low-level signal is received at the base end of the triode 221, the switch device 220 in which the triode 221 is located is turned off.

[0044] The embodiment provided in the application only needs a control signal with small strength to control the turning on or turning off of the switch device, thereby improving the operability of the current sampling system.

[0045] In an embodiment of the utility model, as shown in Figure 3 The signal processing circuit 300 includes an isolation chip 310 and an operational amplifier circuit 320. Here, the isolation chip 310 can be an analog isolation chip, which is used to establish electrical isolation between the collection end and the output end of the isolation chip 310. The collection end of the isolation chip 310 includes a first collection end and a second collection end, and the output end of the isolation chip 310 includes a first output end and a second output end.

[0046] Specifically, the first collection end and the second collection end of the isolation chip 310 are respectively connected with the first end and the second end of the sampling resistor 210 in the current sampling circuit, and the first output end and the second output end of the isolation chip 310 are respectively connected with the first input end and the second input end of the operational amplifier circuit 320, which is used to collect the differential voltage at the sampling resistor 210 and send the differential voltage to the operational amplifier circuit 320. Here, the first collection end and the second collection end of the isolation chip 310 can be respectively provided with a voltage sensor to collect the voltage difference between the two ends of the sampling resistor 210, and then collect the differential voltage of the sampling resistor 210. In addition, the current sampling system can collect the differential voltage by means of Hall sampling and fluxgate detection, which is not limited in the embodiment and is also applicable to the embodiment.

[0047] Further, the operational amplifier circuit 320 is used to perform signal amplification processing on the differential voltage to obtain the differential voltage after amplification processing, and send the differential voltage after amplification processing to the control unit 100.

[0048] Specifically, as shown in Figure 3 The operational amplifier circuit 320 includes an operational amplifier U1, a first resistor R1, a second resistor R2, a third resistor R3 and a fourth resistor R4.

[0049] Further, a first end of the first resistor R1 is connected with the first output end of the isolation chip 310, a second end of the first resistor R1 is connected with the non-inverting input end of the operational amplifier U1, a first end of the second resistor R2 is connected with the second output end of the isolation chip 310, and a second end of the second resistor R2 is connected with the inverting input end of the operational amplifier U1.

[0050] Further, a first end of the third resistor R3 is connected with the inverting input end of the operational amplifier U1, and a second end of the third resistor R3 is connected with the output end of the operational amplifier U1.

[0051] Further, a first end of the fourth resistor R4 is connected with the output end of the operational amplifier U1, and a second end of the fourth resistor R4 is connected with the signal input end of the control unit 100, so as to send the differential voltage after the amplification processing to the control unit 100.

[0052] The embodiment provided in the application can electrically isolate the signal processing circuit at two ends based on the isolation chip, and process the differential voltage based on the operational amplification circuit, thereby improving the signal quality of the differential voltage and the sampling precision of the current sampling system.

[0053] In an embodiment of the utility model, the current sampling system further includes an acousto-optic alarm unit, wherein the acousto-optic alarm unit can be an alarm lamp and a buzzer; the alarm control end of the control unit is connected with the control end of the acousto-optic alarm unit, and is used for controlling the acousto-optic alarm unit to send an acousto-optic alarm signal. Here, a corresponding monitoring program can be arranged in the control unit, as an example, the monitoring program can monitor the battery current of the storage battery, and when the battery current of the storage battery is monitored to be abnormal, the acousto-optic alarm unit is controlled in time to send an acousto-optic alarm signal, so as to prompt relevant staff to handle the abnormal situation. The embodiment provided in the application provides a hardware basis for the current sampling system to realize the alarm function.

[0054] In an embodiment of the utility model, a man-machine interaction interface is arranged at the control unit, wherein the man-machine interaction interface can be a serial touch screen; specifically, the signal interaction end of the control unit is connected with the control end of the man-machine interaction interface, and relevant staff can control the control unit based on the man-machine interaction interface, and check the sampling result of the battery current. The embodiment provided in the application can control the control unit based on the man-machine interaction interface, thereby realizing the control of the current sampling system, and improving the operability of the current sampling system.

[0055] It should be noted that the selection of the control unit, the isolation chip and the operational amplifier circuit and the internal circuit connection mode of the current sampling system can be determined according to actual conditions, and the embodiment is not limited specifically. In addition, the connection mode of each device can be determined according to the specific selection of the device, and the embodiment is not limited specifically. The circuit function of the current sampling system provided in the embodiment is mainly realized through the circuit connection relationship between each circuit module, and does not depend on the program module in a certain circuit module. In addition, each circuit module in the current sampling system can be realized through an analog circuit or a digital circuit, and for the control unit which can implant a program module, the realization of the module function can be realized through the program module provided by the prior art.

[0056] The current sampling system provided in the embodiment of the utility model sets two or more current sampling circuits, each current sampling circuit controls the passage of current through a switching device, and the differential voltage obtained by the current sampling circuit is sent to the control unit after signal conversion through the isolation chip and the operational amplifier circuit, for the control unit to sample the battery current.

[0057] When the battery current is relatively small, the current sampling circuit with a sampling resistor with a large resistance value is started as a small current sampling channel, at this time, the switching device in the small current sampling channel is turned on, and the switching devices in all current sampling circuits except the small current sampling channel are turned off, at this time, the current sampling system uses the signal of the differential voltage corresponding to the small current sampling channel for current sampling; relatively, when the battery current is relatively large, the current sampling circuit with a sampling resistor with a small resistance value is started as a large current sampling channel, at this time, the switching device in the large current sampling channel is turned on, and the switching devices in all current sampling circuits except the large current sampling channel are turned off, at this time, the current sampling system uses the signal of the differential voltage corresponding to the large current sampling channel for current sampling.

[0058] As an example, the current sampling system includes two current sampling circuits, namely a first current sampling circuit and a second current sampling circuit, and includes two signal processing circuits, namely a first signal processing circuit and a second signal processing circuit, wherein the first current sampling circuit corresponds to the first signal processing circuit, and the second current sampling circuit corresponds to the second signal processing circuit, and the resistance value of the first sampling resistor in the first current sampling circuit is greater than the resistance value of the second sampling resistor in the second current sampling circuit.

[0059] When the battery current is small, the first switch device in the first current sampling circuit is turned on, the second switch device in the second current sampling circuit is turned off, the first signal processing circuit collects the differential voltage at the first sampling resistor, and the differential voltage is processed by the first isolation chip and the first operational amplifier circuit in the first signal processing circuit, and then the processed differential voltage is sent to the control unit, so that the control unit determines the battery current. When the battery current is large, the second switch device in the second current sampling circuit is turned on, the first switch device in the first current sampling circuit is turned off, the second signal processing circuit collects the differential voltage at the second sampling resistor, and the differential voltage is processed by the second isolation chip and the second operational amplifier circuit in the second signal processing circuit, and then the processed differential voltage is sent to the control unit, so that the control unit determines the battery current, thereby realizing the segmented sampling of the battery current.

[0060] Further, since the switching time of the current sampling circuit is short, the control and performance of the current sampling system are not affected, but the sampling accuracy of the battery current is greatly improved, and the estimation accuracy of the remaining energy (SOC) of the storage battery is greatly improved.

[0061] On the other hand, the embodiment of the utility model provides a kind of energy storage device, as shown in Figure 4 The energy storage device includes DC / DC converter 700, inverter 800 and current sampling system as described above.

[0062] Specifically, the first positive electrode access end of the DC / DC converter 700 is connected with the positive electrode end BAT+ of the storage battery 400, and the first negative electrode access end of the DC / DC converter 700 is connected with the connection end after the second end of each current sampling circuit 200 in the current sampling system, so that the DC / DC converter 700 can interact with the storage battery 400.

[0063] Further, the second positive electrode access end of the DC / DC converter 700 is connected with the positive electrode access end U+ of the inverter 800, and the second negative electrode access end of the DC / DC converter 700 is connected with the negative electrode access end U- of the inverter 800, and the alternating current end of the inverter 800 is connected with external power equipment (not shown in the figure). Here, the current output by the storage battery 400 can be output to the inverter 800 through the DC / DC converter 700, so that the inverter 800 converts the direct current output by the storage battery 400 into alternating current and outputs the alternating current to external power equipment, wherein the power equipment can be a grid connection point of a power system or other alternating current electrical appliances, and the embodiment is not limited.

[0064] Further, the energy storage device further comprises a maximum power point tracking control solar controller 900 (MPPT) and a first capacitor C1, the maximum power point tracking control solar controller 900 can detect the power generation voltage of the photovoltaic power generation device 1000 such as a solar panel in real time, and track the highest voltage and current value (VI), so that the photovoltaic power generation device 1000 can charge the storage battery 400 with maximum power output.

[0065] Specifically, the first positive electrode access end of the maximum power point tracking control solar controller 900 is connected with the positive electrode end PV+ of the external photovoltaic power generation device 1000, and the first negative electrode access end of the maximum power point tracking control solar controller 900 is connected with the negative electrode end PV- of the external photovoltaic power generation device 1000, so as to receive the output power of the photovoltaic power generation device 1000.

[0066] Further, the second positive electrode access end of the maximum power point tracking control solar controller 900 is connected with the second positive electrode access end of the DC / DC converter 700, the second negative electrode access end of the maximum power point tracking control solar controller 900 is connected with the second negative electrode access end of the DC / DC converter 700, and the second positive electrode access end of the maximum power point tracking control solar controller 900 is also connected with the first end of the first capacitor C1, and the second end of the first capacitor C1 is connected with the second negative electrode access end of the DC / DC converter 700, so as to be connected to the storage battery 400 through the DC / DC converter 700, so that the maximum power point tracking control solar controller 900 can charge the storage battery 400 based on the output power of the photovoltaic power generation device 1000.

[0067] The energy storage device provided by the application can charge the storage battery based on the photovoltaic power generation device, can supply power to the external power equipment based on the storage battery, and can sample the battery current of the storage battery in real time, thereby improving the calculation ability of the remaining power of the storage battery and improving the operation reliability of the energy storage device.

[0068] The above-mentioned embodiments only express several embodiments of the application, the description is more specific and detailed, but it cannot be understood as the limitation of the scope of the application patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the application, a number of modifications and improvements can be made, which belong to the protection scope of the application. Therefore, the protection scope of the application patent should be subject to the appended claims.

Claims

1. A current sampling system for sampling a battery current of a battery, characterized by, The current sampling system comprises a control unit, a plurality of current sampling circuits and a plurality of signal processing circuits, wherein the current sampling circuit comprises a sampling resistor and a switching device, the switching device is used to make the current sampling circuit in a pass-through state or a circuit-breaking state, the sampling resistor in each current sampling circuit is different in resistance, and the current sampling circuit corresponds to the signal processing circuit one by one; The connection end after the first end of each current sampling circuit is connected with the negative electrode end of the storage battery, and the connection end after the second end of each current sampling circuit is connected with an external power device, so that the sampling resistor in each current sampling circuit is connected in series between the negative electrode end of the storage battery and the power device; The signal receiving end of each signal processing circuit is connected with the sampling resistor in the current sampling circuit corresponding to the signal processing circuit, used to collect the differential voltage across the sampling resistor and send the differential voltage to the control unit; The control unit is used to receive the differential voltage and determine the battery current of the storage battery based on the differential voltage.

2. The current sampling system of claim 1, wherein, The sampling resistor and the switching device in the current sampling circuit are connected in series between the first end of the current sampling circuit and the second end of the current sampling circuit, when the switching device is turned on, the negative electrode end of the storage battery and the power device are connected through the current sampling circuit for current interaction, and when the switching device is turned off, the negative electrode end of the storage battery and the power device are disconnected.

3. The current sampling system of claim 2, wherein, The control end of the switching device is connected with a remote host computer, used to be controlled to be in a turned-on or turned-off state.

4. The current sampling system of claim 3, wherein, The switching device comprises a transistor and a diode. The connection end after the cathode end of the diode is connected with the collector end of the transistor is connected with the first end of the sampling resistor, and the connection end after the anode end of the diode is connected with the emitter end of the transistor is used as the second end of the current sampling circuit. The base end of the transistor is connected with the host computer, used to be controlled to make the transistor in a turned-on or turned-off state.

5. The current sampling system of claim 1, wherein, The signal processing circuit comprises an isolation chip and an operational amplifier circuit. The first collection end and the second collection end of the isolation chip are connected with the first end and the second end of the sampling resistor in the current sampling circuit respectively, the first output end and the second output end of the isolation chip are connected with the first input end and the second input end of the operational amplifier circuit respectively, used to collect the differential voltage at the sampling resistor and send the differential voltage to the operational amplifier circuit; The operational amplifier circuit is used to perform signal amplification processing on the differential voltage, obtain the differential voltage after amplification processing, and send the differential voltage after amplification processing to the control unit.

6. The current sampling system of claim 5, wherein, The operational amplifier circuit comprises an operational amplifier, a first resistor, a second resistor, a third resistor and a fourth resistor. A first end of the first resistor is connected with a first output end of the isolation chip, a second end of the first resistor is connected with a non-inverting input end of the operational amplifier, a first end of the second resistor is connected with a second output end of the isolation chip, and a second end of the second resistor is connected with an inverting input end of the operational amplifier; A first end of the third resistor is connected with the inverting input end of the operational amplifier, and a second end of the third resistor is connected with an output end of the operational amplifier; A first end of the fourth resistor is connected with the output end of the operational amplifier, and a second end of the fourth resistor is connected with a signal input end of the control unit.

7. The current sampling system of claim 1, wherein, The current sampling system further comprises an acousto-optic alarm unit; An alarm control end of the control unit is connected with a control end of the acousto-optic alarm unit, for controlling the acousto-optic alarm unit to send an acousto-optic alarm signal.

8. The current sampling system of claim 7, wherein, A man-machine interaction interface is arranged at the control unit, and a signal interaction end of the control unit is connected with a control end of the man-machine interaction interface.

9. An energy storage device, characterized by, The energy storage device comprises a DC / DC converter, an inverter, and the current sampling system according to any one of claims 1 to 8; A first positive access end of the DC / DC converter is connected with a positive end of the storage battery, and a first negative access end of the DC / DC converter is connected with a connection end after each current sampling circuit is connected with a second end; A second positive access end of the DC / DC converter is connected with a positive access end of the inverter, a second negative access end of the DC / DC converter is connected with a negative access end of the inverter, and an alternating current end of the inverter is connected with an external power equipment.

10. The energy storage device of claim 9, wherein, The energy storage device further comprises a maximum power point tracking control solar controller and a first capacitor; A first positive access end of the maximum power point tracking control solar controller is connected with a positive end of an external photovoltaic power generation equipment, and a first negative access end of the maximum power point tracking control solar controller is connected with a negative end of the photovoltaic power generation equipment; A second positive access end of the maximum power point tracking control solar controller is connected with the second positive access end of the DC / DC converter, and a second negative access end of the maximum power point tracking control solar controller is connected with the second negative access end of the DC / DC converter; A first end of the first capacitor is connected with the second positive access end of the DC / DC converter and the second positive access end of the maximum power point tracking control solar controller respectively, and a second end of the first capacitor is connected with the second negative access end of the DC / DC converter.

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