Current detection device of power supply system and power supply system

Abstract

A current detection device of a power supply system and the power supply system, including: a first current measurement element configured to measure a leakage current of a power supply and configured to allow a first power harness and a second power harness to pass through; a second current measuring element configured to measure an operating current of the power source and configured to be passed through by the first power harness or the second power harness; the acquisition unit is respectively connected with the first current measuring element and the second current measuring element and is configured to convert an analog signal representing leakage current into a digital signal and convert an analog signal representing working current into a digital signal; the working current comprises a discharging current and / or a charging current of the power supply system.

Description

Technical Field

[0001] The present application relates to the field of power supply technology, and in particular to a current detection device and a power supply system. Background Art

[0002] TN-S power grid, also known as TN-S zero protection system, is a system with a dedicated neutral line and direct grounding of the neutral point, commonly known as a three-phase five-wire system. The metal casing of the electrical equipment in the TN-S power grid is connected to the dedicated neutral line, and the repeated grounding wire is connected to the neutral line to protect personal safety.

[0003] The energy storage system uses a non-isolated inverter (a converter that converts DC power such as batteries and storage bottles into constant frequency and voltage or frequency and voltage regulated AC power) to convert the battery's DC power into AC power for grid connection. At this time, the grid's N line (Neutral Line, also known as the zero line) and PE line (Protective Earthing Conductor, also known as the ground line) are connected together at the remote end, resulting in non-isolation between the P+ (positive pole) and P- (negative pole) on the battery side and the PE line. It is impossible to use traditional insulation detection methods to detect the impedance between the DC bus and PE to determine whether there is leakage current in the power supply casing. Summary of the invention

[0004] The purpose of the embodiment of the present application is to provide a current detection device of a power supply system and a power supply system to detect leakage current in a power supply circuit. The specific technical solution is as follows:

[0005] An embodiment of the present application provides a current detection device for a power supply system, comprising: a first current measuring element is configured to measure the leakage current of the power supply, and is configured to allow a first power harness and a second power harness to pass through; a second current measuring element is configured to measure the working current of the power supply, and is configured to allow the first power harness or the second power harness to pass through; an acquisition unit is respectively connected to the first current measuring element and the second current measuring element, and is configured to convert an analog signal representing the leakage current into a digital signal, and convert an analog signal representing the working current into a digital signal; wherein the working current includes a discharge current and / or a charging current of the power supply system.

[0006] In a possible implementation, the first current measuring element includes an annular portion, and along the direction in which the first power harness and the second power harness pass through the first current measuring element, a projection of the second current measuring element is located within the projection of the annular portion, wherein the first power harness is the positive bus of the power supply, and the second power harness is the negative bus of the power supply.

[0007] In a possible implementation, the second current measuring element is located in the annular portion.

[0008] In a possible implementation, the first current measuring element includes a fluxgate sensor, and the second current measuring element includes a fluxgate sensor or a Hall sensor.

[0009] In a possible implementation manner, a detection accuracy of the first current measuring element is higher than or equal to a detection accuracy of the second current measuring element.

[0010] In a possible implementation, the present invention further includes: a driving circuit, which is respectively connected to the first current measuring element and the second current measuring element and is configured to drive the first current measuring element and the second current measuring element; a micro control unit, which is respectively connected to the first current measuring element, the second current measuring element and the acquisition unit; and a power supply unit, which is respectively connected to the acquisition unit, the driving circuit and the micro control unit and is configured to supply power to the acquisition unit, the driving circuit and the micro control unit.

[0011] In a possible implementation, the present invention further includes: a driving circuit, which is respectively connected to the first current measuring element and the second current measuring element and is configured to drive the first current measuring element and the second current measuring element; a micro control unit, wherein the acquisition unit is an internal unit module of the micro control unit, and the micro control unit is connected to the first current measuring element and the second current measuring element through the acquisition unit; and a power supply unit, which is respectively connected to the acquisition unit, the driving circuit and the micro control unit and is configured to supply power to the acquisition unit, the driving circuit and the micro control unit.

[0012] In a possible implementation manner, the device further includes: a communication unit; the communication unit is connected to the micro control unit and the power supply unit, and is configured to: send a leakage current measurement signal and an operating current measurement signal to the outside.

[0013] In a possible implementation manner, the device further includes: a watchdog unit; the watchdog unit is connected to the micro control unit and is configured to send a reset signal to the micro control unit in response to a failure of the micro control unit.

[0014] An embodiment of the present application also provides a power supply system, including: a battery module, a first power harness, and a second power harness; the first power harness connects the positive pole of the battery module to the positive output terminal of the battery module; the second power harness connects the negative pole of the battery module to the negative output terminal of the battery module; and also includes a current detection device as described in any one of the embodiments of the present application.

[0015] In a possible implementation manner, the first power harness and the second power harness pass through the first current measuring element, and the first power harness or the second power harness passes through the second current measuring element.

[0016] Beneficial effects of the embodiments of the present application:

[0017] In the current detection device of the power supply system provided in the embodiment of the present application, a first current measuring element is passed through by the first power harness and the second power harness, and the first current measuring element detects the leakage current of the power supply by detecting the difference between the vector currents of the first power harness and the second power harness; the second current measuring element is passed through by one of the first power harness or the second power harness, and the current measuring element detects the working current of the power supply by detecting the vector current value of the first power harness or the second power harness, and the acquisition unit is connected to the first current measuring element and the second current measuring element respectively, and can convert the analog signal representing the leakage current into a digital signal, and convert the analog signal representing the working current into a digital signal, thereby realizing the detection of the leakage current while detecting the working current. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other embodiments can also be obtained based on these drawings.

[0019] Figure 1 A first schematic diagram of a current detection device of a power supply system according to an embodiment of the present application;

[0020] Figure 2 A schematic diagram of a first position of a current measuring element in a current detection device of a power supply system according to an embodiment of the present application;

[0021] Figure 3 A schematic diagram of a second position of a current measuring element in a current detection device of a power supply system according to an embodiment of the present application;

[0022] Figure 4 A second schematic diagram of the current detection device of the power supply system according to an embodiment of the present application;

[0023] Figure 5 A third schematic diagram of the current detection device of the power supply system according to an embodiment of the present application;

[0024] Figure 6 A fourth schematic diagram of a current detection device of a power supply system according to an embodiment of the present application;

[0025] Figure 7 A fifth schematic diagram of the current detection device of the power supply system according to an embodiment of the present application;

[0026] Figure 8 This is a sixth schematic diagram of the current detection device of the power supply system according to an embodiment of the present application. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present application to clearly and in detail describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field based on the present application belong to the scope of protection of the present application.

[0028] In the related technology, the energy storage system uses a non-isolated inverter (a converter that converts DC power such as batteries, storage bottles, etc. into constant frequency and voltage or frequency and voltage regulated AC power) to convert the DC power of the battery into AC power and then connect it to the grid. At this time, the N line (Neutral Line, also known as the zero line) and PE line (Protective Earthing Conductor, also known as the ground line) of the power grid are connected together at the remote end, resulting in non-isolation between the P+ (positive pole), P- (negative pole) and PE line on the battery side, and the traditional insulation detection method cannot be used to detect the impedance between the DC bus and PE to determine whether there is leakage current in the power supply casing.

[0029] In order to detect leakage current in a circuit, the present application provides a current detection device for a power supply system, see Figure 1 ,include:

[0030] The first current measuring element 101 is configured to: measure the leakage current of the power supply, and is configured to allow the first power line bundle 201 and the second power line bundle 202 to pass through;

[0031] The second current measuring element 102 is configured to: measure the working current of the power supply, and is configured to allow the first power harness 201 or the second power harness 202 to pass through;

[0032] The acquisition unit 103 is connected to the first current measuring element 101 and the second current measuring element 102 respectively, and is configured to: convert the analog signal representing the leakage current into a digital signal, and convert the analog signal representing the working current into a digital signal;

[0033] The operating current includes a discharge current and / or a charge current of the power supply system.

[0034] The first current measuring element 101 is used to measure the leakage current of the power supply. The first power harness 201 and the second power harness 202 are two harnesses with opposite positive and negative polarities in the total power supply harness of the power supply. Specifically, the first power harness 201 can be the positive bus of the power supply, and the second power harness 202 can be the negative bus of the power supply. The first current measuring element 101 can detect the sum of the vector currents of each harness passing through itself. When there is no leakage current, the currents in the first power harness 201 and the second power harness 202 are equal in magnitude and opposite in direction. At this time, the vector current detected by the first current measuring element 101 is 0; when there is leakage current, the currents in the first power harness 201 and the second power harness 202 are not equal in magnitude, and the vector current detected by the first current measuring element 101 is the leakage current.

[0035] The second current measuring element 102 is used to measure the working current of the power supply. The first power harness 201 or the second power harness 202 passes through the second current measuring element 102. In some scenarios, the positive bus of the power supply can be passed through the second current measuring element 102, so that the working current of the power supply can be accurately detected. In some scenarios, the negative bus of the power supply can also be passed through the second current measuring element 102. When there is no leakage current, the current in the first power harness 201 and the second power harness 202 is equal, and the vector current detected by the second current measuring element 102 is the working current of the power supply; when there is leakage current, in order to ensure the safety of electricity use, the power switch of the power supply will be disconnected, so it will not have a significant impact on the detection of the working current.

[0036] In an example, the acquisition unit 103 may be an analog-to-digital converter, which converts an analog signal representing the leakage current into a digital signal and converts an analog signal representing the working current into a digital signal, so that the processor can process the current signal.

[0037] The first current measuring element 101 and the second current measuring element 102 are arranged in the circuit, so that the leakage current of the circuit can be measured while measuring the working current, thereby achieving a real-time detection effect.

[0038] In one possible implementation, see Figure 2 The first current measuring element 101 includes an annular portion 1011 , and along the direction in which the first power line 201 and the second power line 202 pass through the first current measuring element 101 , the projection of the second current measuring element 102 is located within the projection of the annular portion 1011 .

[0039] The projection of the second current measuring element 102 is located within the projection of the annular portion 1011. Therefore, when passing through the first current measuring element 101 and the second current measuring element 102, the first power harness 201 and the second power harness 202 do not need to be bent and can be wired vertically. The vertical wiring method can reduce the wiring length and thus reduce the line resistance. It can also reduce the potential safety hazards at the corners / bends of the line and improve the safety of the circuit.

[0040] In one possible implementation, see Figure 3 , the second current measuring element 102 is located in the annular portion 1011 .

[0041] Disposing the second current measuring element 102 inside the annular portion 1011 of the first current measuring element 101 can reduce the occupied space of the current detection device, thus facilitating miniaturization.

[0042] In one possible implementation, see Figure 4 The first current measuring element 101 includes a fluxgate sensor, and the second current measuring element 102 includes a fluxgate sensor or a Hall sensor.

[0043] The leakage current is usually small in value. In the related art, the leakage current is detected by using a Hall element. The Hall element is easily disturbed by the external environment, resulting in a large zero drift and temperature drift, which causes a large error and inaccurate detection data. The first current measuring element 101 of the embodiment of the present application is a fluxgate sensor. The minimum detection unit of the fluxgate sensor can be 0.1mA, and the detection range can be 0~3A. The fluxgate sensor has high precision, wide measurement range, strong anti-interference ability, fast response speed, and low power consumption, and can detect the leakage current more accurately.

[0044] The second current measuring element 102 can be a fluxgate sensor or a Hall sensor. The second current measuring element 102 detects the working current, and has lower accuracy requirements than leakage current detection. The Hall element can also meet the measurement requirements. The fluxgate sensor has higher accuracy, and the Hall sensor has lower cost. The fluxgate sensor or the Hall sensor can be selected according to actual needs.

[0045] In a possible implementation, the detection accuracy of the first current measuring element 101 is higher than or equal to the detection accuracy of the second current measuring element 102 .

[0046] The first current measuring element 101 measures the leakage current, and the second current measuring element 102 measures the working current. The requirement for the leakage current detection accuracy is higher than the detection accuracy of the working current. This is because the existence of the leakage current will threaten the personal safety of the user, so the detection accuracy of the first current measuring element 101 is required to be higher. The second current measuring element 102 is used to detect the working current and will not threaten personal safety. The second current detecting element 102 can use a component with slightly lower accuracy to save component costs.

[0047] In one possible implementation, see Figure 5 , the current detection device also includes:

[0048] The driving circuit 104 is connected to the first current measuring element 101 and the second current measuring element 102 respectively, and is configured to: drive the first current measuring element 101 and the second current measuring element 102;

[0049] The micro control unit 105 is connected to the first current measuring element 101, the second current measuring element 102 and the acquisition unit 103 respectively;

[0050] The power supply unit 106 is connected to the acquisition unit 103 , the driving circuit 104 and the micro control unit 105 respectively, and is configured to supply power to the acquisition unit 103 , the driving circuit 104 and the micro control unit 105 .

[0051] The driving circuit 104 is connected to the power supply unit 106 , drives the first current measuring element 101 and the second current measuring element 102 , and provides power to the first current measuring element 101 and the second current measuring element 102 at the same time.

[0052] In one example, the power supply unit 106 includes a power conversion sub-circuit and an LDO (Low-dropout regulator). The power supply unit 106 is connected to an external power supply, converts the voltage of the external power supply and supplies power to the acquisition unit 103, the drive circuit 104, and the micro control unit 105 to ensure the normal operation of the current detection device.

[0053] In one example, the microcontroller unit 105 is an MCU (Microcontroller Unit), and the MCU communicates with the acquisition unit 103 via an SPI (Serial Peripheral Interface). The microcontroller unit 105 is used to process the digital signal output by the acquisition unit 103 and transmit it to other devices, for example, to a BMS (Battery Management System) or to a PCS (Power Conversion System).

[0054] In one possible implementation, see Figure 6 , also includes:

[0055] The driving circuit 104 is connected to the first current measuring element 101 and the second current measuring element 102 respectively, and is configured to: drive the first current measuring element 101 and the second current measuring element 102;

[0056] The micro control unit 105 and the acquisition unit 103 are internal unit modules of the micro control unit 105 , and the micro control unit 105 is connected to the first current measuring element 101 and the second current measuring element 102 through the acquisition unit 103 ;

[0057] The power supply unit 106 is connected to the acquisition unit 103 , the driving circuit 104 and the micro control unit 105 respectively, and is configured to supply power to the acquisition unit 103 , the driving circuit 104 and the micro control unit 105 .

[0058] In one example, the acquisition unit 103 is an analog-to-digital converter, and the microcontroller unit 105 includes an MCU and the acquisition unit 103. The microcontroller unit 105 converts the analog signal representing the leakage current detected by the first current measuring element 101 of the acquisition unit 103 into a digital signal, converts the analog signal representing the working current detected by the second current measuring element 102 into a digital signal, and transmits the digital signal to the MCU. The MCU processes the digital signal and transmits it to the BMS or PCS.

[0059] The description related to the driving circuit 104 and the power supply unit 106 can refer to other related embodiments of the present application and will not be repeated here.

[0060] The acquisition unit 103 is arranged inside the micro control unit 105, which reduces the external wiring harness connection, makes data transmission more accurate and convenient, simplifies the structure of the current detection device, and reduces safety hazards.

[0061] In one possible implementation, see Figure 7 , further comprising: a communication unit 107;

[0062] The communication unit 107 is connected to the micro control unit 105 and the power supply unit 106 , and is configured to send a leakage current measurement signal and an operating current measurement signal to the outside.

[0063] In one example, the communication unit 107 is a CAN (Controller Area Network) transceiver, which is a serial communication protocol bus for real-time applications and can use twisted pair cables to transmit signals. After the micro control unit 105 obtains and processes the digital signal output by the acquisition unit 103, it transmits the processed leakage current measurement signal and working current measurement signal to the BMS or PCS through the communication unit 107.

[0064] In one possible implementation, see Figure 8 , further comprising: a watchdog unit 108;

[0065] The watchdog unit 108 is connected to the micro control unit 105 and is configured to send a reset signal to the micro control unit 105 in response to a failure of the micro control unit 105 .

[0066] The watchdog timer unit 108 is a timer circuit, the input end of which is called kicking the dog / service the dog. The input end and the output end are respectively connected to the micro control unit 105. When the micro control unit 105 works normally, it outputs a signal to the dog feeding end at regular intervals to reset the timer. If the watchdog timer unit 108 does not receive the dog feeding data from the micro control unit 105 within the specified time, the watchdog unit 108 outputs a reset signal to the micro control unit 105 to restart and reset the micro control unit 105.

[0067] The watchdog unit 108 resets and restarts the microcontroller unit 105 when a fault occurs, thereby improving the ability of the current detection device to cope with sudden faults and ensuring the normal operation of the current detection device.

[0068] The present application also provides a power supply system, including:

[0069] A battery module, a first power harness, and a second power harness;

[0070] A first power harness connects the positive electrode (B+) of the battery module to the positive output terminal (P+) of the battery module;

[0071] A second power harness connects the negative electrode (B-) of the battery module to the negative output terminal (P-) of the battery module;

[0072] It also includes a current detection device as described in any one of the embodiments of the present application.

[0073] For the relevant description of the power supply system, please refer to the relevant embodiments of the current detection device of the present application, which will not be repeated here.

[0074] In a possible implementation manner, the first power harness and the second power harness pass through the first current measuring element, and the first power harness or the second power harness passes through the second current measuring element.

[0075] The currents in the first power harness 201 and the second power harness 202 are in opposite directions and pass through the first current measuring element 101 at the same time. When there is no leakage current in the power supply, the currents in the first power harness 201 and the second power harness 202 are equal in magnitude, the positive and negative currents cancel each other out, and the detection value of the first current measuring element 101 is 0. When there is leakage current in the power supply, the currents in the first power harness 201 and the second power harness 202 are not equal in magnitude, and the detection value of the first current measuring element 101 is not 0.

[0076] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0077] Each embodiment in this specification is described in a related manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the device embodiment.

[0078] The above description is only a preferred embodiment of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application are included in the protection scope of the present application.

Claims

1. A current detection device for a power supply system, characterized in that: include: The first current measuring element is configured to: measure a leakage current of a power source, and is configured to allow the first power harness and the second power harness to pass through; The second current measuring element is configured to: measure the operating current of the power supply, and is configured to allow the first power harness or the second power harness to pass through; The acquisition unit is connected to the first current measuring element and the second current measuring element respectively, and is configured to: convert the analog signal representing the leakage current into a digital signal, and convert the analog signal representing the working current into a digital signal; Wherein, the operating current includes a discharge current and / or a charge current of the power supply system.

2. The current detection device according to claim 1, characterized in that: The first current measuring element comprises an annular portion, and along the direction in which the first power line bundle and the second power line bundle pass through the first current measuring element, a projection of the second current measuring element is located within a projection of the annular portion; The first power wiring harness is a positive bus of the power source, and the second power wiring harness is a negative bus of the power source.

3. The current detection device according to claim 2, characterized in that: The second current measuring element is located within the annular portion.

4. The current detection device according to any one of claims 1 to 3, characterized in that: The first current measuring element includes a fluxgate sensor, and the second current measuring element includes a fluxgate sensor or a Hall sensor.

5. The current detection device according to any one of claims 1 to 4, characterized in that: A detection accuracy of the first current measuring element is higher than or equal to a detection accuracy of the second current measuring element.

6. The current detection device according to any one of claims 1 to 5, characterized in that: Also includes: a driving circuit, connected to the first current measuring element and the second current measuring element respectively, and configured to: drive the first current measuring element and the second current measuring element; A micro control unit, connected to the first current measuring element, the second current measuring element and the acquisition unit respectively; The power supply unit is respectively connected to the acquisition unit, the drive circuit and the micro control unit, and is configured to supply power to the acquisition unit, the drive circuit and the micro control unit.

7. The current detection device according to any one of claims 1 to 5, characterized in that: Also includes: a driving circuit, connected to the first current measuring element and the second current measuring element respectively, and configured to: drive the first current measuring element and the second current measuring element; A micro control unit, wherein the acquisition unit is an internal unit module of the micro control unit, and the micro control unit is connected to the first current measuring element and the second current measuring element through the acquisition unit; The power supply unit is respectively connected to the acquisition unit, the drive circuit and the micro control unit, and is configured to supply power to the acquisition unit, the drive circuit and the micro control unit.

8. The current detection device according to claim 6 or 7, characterized in that: Also includes: Communication unit; The communication unit is connected to the micro control unit and the power supply unit, and is configured to send a leakage current measurement signal and an operating current measurement signal to the outside.

9. The current detection device according to any one of claims 6 to 8, characterized in that: Also includes: Watchdog unit; The watchdog unit is connected to the micro control unit and is configured to send a reset signal to the micro control unit in response to a failure of the micro control unit.

10. A power supply system, comprising: A battery module, a first power harness, and a second power harness; The first power harness connects the positive electrode of the battery module to the positive output terminal of the battery module; The second power harness connects the negative electrode of the battery module to the negative output terminal of the battery module; It is characterized in that it also includes the current detection device according to any one of claims 1-9.

11. The power supply system according to claim 10, characterized in that: The first power harness and the second power harness pass through the first current measuring element, and the first power harness or the second power harness passes through the second current measuring element.

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