CN218917511U

CN218917511U - Charging pile grounding impedance detection circuit

Info

Publication number: CN218917511U
Application number: CN202222949935.7U
Authority: CN
Inventors: 付好名; 刘洪玮
Original assignee: Zhejiang Greatway Electrical Tool Co ltd
Current assignee: Zhejiang Greatway Electrical Tool Co ltd
Priority date: 2022-11-02
Filing date: 2022-11-02
Publication date: 2023-04-25
Anticipated expiration: 2032-11-02

Abstract

The utility model provides a charging pile grounding impedance detection circuit which comprises a signal sampling module and an isolation conversion module which are connected; the input end of the signal sampling module is respectively connected with a live wire and a zero wire of the power grid and is used for respectively collecting input voltage signals of the zero wire and the live wire; the input end of the isolation conversion module is connected with the output end of the signal sampling module, the isolation conversion module comprises an optical coupler, a first pin of the optical coupler is connected with the signal sampling module, and the isolation conversion module converts the input voltage signals of the zero line and the live line to obtain output voltage signals; the output voltage signal is used for determining whether the ground impedance is abnormal; the circuit provided by the utility model realizes detection of the input grounding impedance of the charging pile, and is beneficial to improving the safety of the charging pile.

Description

Charging pile grounding impedance detection circuit

Technical Field

The utility model relates to the technical field of charging piles, in particular to a charging pile grounding impedance detection circuit.

Background

Electric vehicles are becoming more popular in the market, and the amount of charging piles is greatly increased. The charging pile is used as high-voltage equipment, and has high requirements on safety. The continuity detection of the grounding conductor is an important ring, so that not only can the electric automobile be protected, but also the personal safety can be protected. Different areas have different quality standards for the charging piles. For example, some areas have special requirements for the input grounding of the charging pile, namely, the input grounding impedance is required to be higher than a threshold value, and the charging pile is protected.

When the input grounding impedance of the charging pile is abnormal, namely, the abnormal access of the grounding wire of the charging pile is indicated, the grounding wire is not grounded, and potential safety hazards exist under the condition. Therefore, how to realize the input ground impedance detection of the charging pile is a problem at present.

Disclosure of Invention

In view of this, the present utility model provides a circuit for detecting the ground impedance of a charging pile, which is beneficial to improving the safety of the charging pile.

According to one aspect of the utility model, a charging pile grounding impedance detection circuit is provided, which comprises a signal sampling module and an isolation conversion module which are connected;

the input end of the signal sampling module is respectively connected with a live wire and a zero wire of the power grid and is used for respectively collecting input voltage signals of the zero wire and the live wire;

the input end of the isolation conversion module is connected with the output end of the signal sampling module, the isolation conversion module comprises an optical coupler, a first pin of the optical coupler is connected with the signal sampling module, and the isolation conversion module converts the input voltage signals of the zero line and the live line to obtain output voltage signals; the output voltage signal is used to determine whether there is an abnormality in the ground impedance.

Optionally, the detection circuit further includes a main control module, the main control module is connected with the isolation conversion module, and the main control module determines whether the ground impedance of the charging pile is abnormal according to the output voltage signal.

Optionally, the second pin and the third pin of the optocoupler are grounded respectively, and the fourth pin of the optocoupler is connected to a power supply voltage.

Optionally, the signal sampling module includes a first diode and a second diode, the first diode is connected to a live wire of the power grid, and the second diode is connected to a zero line of the power grid.

Optionally, the signal sampling module further includes a plurality of resistors connected in series, a first end formed by connecting the plurality of resistors in series is grounded, and a second end formed by connecting the plurality of resistors in series is connected to a second pin of the optocoupler.

Optionally, the isolation conversion module further includes at least one capacitor, a first end of the capacitor is connected to the third pin of the optocoupler and the ground, and a second end of the capacitor is connected to the fourth pin of the optocoupler and the output end of the isolation conversion module.

Optionally, the isolation conversion module further includes a fourth resistor, a first end of the fourth resistor is connected to the power voltage, and a second end of the fourth resistor is connected to a fourth pin of the optocoupler and an output end of the isolation conversion module respectively.

Optionally, the isolation conversion module further includes a fifth resistor, a first end of the fifth resistor is connected to the power supply voltage and a fourth pin of the optocoupler, and a second end of the fifth resistor is connected to an output end of the isolation conversion module.

Optionally, the signal sampling module further includes a first resistor, a second resistor and a third resistor connected in series, a first end formed by connecting the first resistor, the second resistor and the third resistor in series is grounded, and a second end formed by connecting the first resistor, the second resistor and the third resistor is connected to a second pin of the optocoupler.

Optionally, the isolation conversion module includes a first capacitor and a second capacitor connected in parallel, a first end formed by connecting the first capacitor and the second capacitor in parallel is respectively connected to a third pin of the optocoupler and ground, and a second end formed by connecting the first end and the second end of the second capacitor in parallel is respectively connected to a fourth pin of the optocoupler and an output end of the isolation conversion module.

Compared with the prior art, the utility model has the beneficial effects that:

according to the charging pile grounding impedance detection circuit provided by the utility model, the signal sampling module is used for acquiring and obtaining the input voltage signals of the zero line and the live line of the power grid, and the output voltage signals are obtained through conversion, so that whether the grounding impedance is abnormal can be determined according to the output voltage signals, and the safety of the charging pile is improved; the circuit is composed of a common resistor, a common capacitor, a common diode and a common optocoupler, and has the advantages of small occupied volume, low cost and high practicability.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the utility model and together with the description, serve to explain the principles of the utility model. It is evident that the drawings in the following description are only some embodiments of the present utility model and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art.

Fig. 1 is a schematic diagram of a circuit for detecting ground impedance of a charging pile according to an embodiment of the present utility model;

fig. 2 is a schematic structural diagram of a ground impedance detection circuit of a charging pile according to another embodiment of the present utility model;

FIG. 3 is a schematic diagram of an output voltage signal when the ground impedance of a charging pile is normal according to another embodiment of the present utility model;

fig. 4 is a schematic diagram of a charging pile connection according to another embodiment of the present utility model.

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the present disclosure. One skilled in the relevant art will recognize, however, that the disclosed aspects may be practiced without one or more of the specific details, or with other methods, materials, apparatus, etc. In other instances, well-known technical solutions have not been shown or described in detail to avoid obscuring aspects of the present disclosure. The same reference numerals in the drawings denote the same or similar structures, and thus detailed descriptions thereof will be omitted.

The terms "a," "an," "the," "said" and "at least one" are used to indicate the presence of one or more elements/components/etc.; the terms "comprising," "having," and "provided" are used in an open-ended fashion and mean that additional elements/components/etc., may be present in addition to the listed elements/components/etc.

As shown in fig. 1, an embodiment of the utility model discloses a charging pile grounding impedance detection circuit. Referring to fig. 1, the inputs of the charging post include a live input (l_input), a neutral input (n_input), and a ground input (PE). Wherein, the live wire input of charging stake is connected in the live wire (L line) of electric wire netting. The zero line input end of the charging pile is connected with the zero line (N line) of the power grid. The ground input end of the charging pile is connected to the ground line (PE line) of the power grid. The PE wire can ensure that the shell is safe under various conditions (including fault states) in the charging process of the charging pile and the electric automobile, and cannot cause harm to the electric automobile and the human body. When the grounding wire of the charging pile is connected abnormally, namely the charging pile is not grounded, namely the protection grounding conductor of the charging pile is discontinuous. When the grounding wire of the charging pile is correctly connected, the charging pile is grounded, namely the protection grounding conductor of the charging pile is continuous.

The charging pile grounding impedance detection circuit comprises a signal sampling module and an isolation conversion module which are connected. The input end of the signal sampling module is respectively connected with a live wire and a zero wire of the power grid and is used for respectively collecting an input voltage signal of the zero wire and an input voltage signal of the live wire. The input end of the isolation conversion module is connected with the output end of the signal sampling module, and the isolation conversion module converts the input voltage signal of the zero line and the input voltage signal of the fire wire to obtain an output voltage signal. The output voltage signal is used for determining whether the ground impedance is abnormal.

In a specific implementation, for example, when the output voltage signal is greater than or equal to a first preset threshold, it is determined that the ground impedance is abnormal. And when the output voltage signal is smaller than a first preset threshold value, determining that the grounding impedance is normal. Alternatively, it may be determined that the ground impedance is abnormal when the output voltage signal is equal to or greater than the second preset threshold. And when the output voltage signal is smaller than a third preset threshold value, determining that the grounding impedance is normal. Wherein the second preset threshold is greater than the third preset threshold.

Specifically, in this embodiment, the signal sampling module includes a first diode D1 and a second diode D2, where the first diode D1 is connected to a live wire of the power grid, that is, the first diode D1 is connected to the live wire of the power grid through a live wire input end of the charging pile. The second diode D2 is connected to the neutral line of the power grid, that is, the first diode D1 is connected to the neutral line of the power grid through the neutral line input terminal of the charging pile. Because above-mentioned live wire input and zero line input all are connected in a diode of this application, consequently need not consider live wire input and zero line input to appear reversing in the installation for it is more convenient to fill the installation of electric pile, does benefit to and improves installation effectiveness, and the practicality is stronger.

The utility model realizes sampling of the input voltage signal of the zero line and the input voltage signal of the fire wire based on one signal sampling module, does not need to arrange two sampling modules for the zero line and the fire wire, and is beneficial to reducing the cost of the detection circuit.

In this embodiment, the isolation conversion module includes an optocoupler PC1, a first pin (i.e., pin 1) of the optocoupler PC1 is connected to the signal sampling module, a second pin (i.e., pin 2) of the optocoupler PC1 is connected to PE ground, a third pin (i.e., pin 3) is connected to signal ground SGND, and a fourth pin (i.e., pin 4) of the optocoupler PC1 is connected to a power supply voltage. Specifically, the signal sampling module further includes a plurality of resistors connected in series, a first end formed by connecting the plurality of resistors in series is grounded, and a second end formed by connecting the plurality of resistors in series is connected to a second pin of the optocoupler PC 1. The pin 1 of the optocoupler PC1 is connected to the first diode D1 and the second diode D2, respectively. The power supply voltage is VDD voltage. Illustratively, the VDD voltage may be, for example, 3.3V.

The utility model isolates the output end and the input end of the grounding impedance detection circuit based on the optocoupler PC1, realizes unidirectional transmission of signals, realizes electric isolation of the input end and the output end, has no influence on the input end by the output signals, has strong anti-interference capability, and is beneficial to improving the working stability of the circuit.

Referring to fig. 1, in the present embodiment, the number of the resistors is three. That is, the signal sampling module includes a first resistor R1, a second resistor R2, and a third resistor R3 connected in series. The first resistor R1, the second resistor R2 and the third resistor R3 are connected in series, one end of the first resistor R is grounded, and the other end of the first resistor R is connected to the pin 2 of the optocoupler PC 1. As an alternative embodiment, the first resistor R1, the second resistor R2, and the third resistor R3 have the same resistance, for example, may be 330kΩ.

With continued reference to fig. 1, in this embodiment, the isolation conversion module further includes a fourth resistor R4, a fifth resistor R5, and a first capacitor C1 and a second capacitor C2 connected in parallel, where a first end of the fourth resistor R4 is connected to a power supply voltage, and a second end of the fourth resistor R4 is connected to the pin 4 of the optocoupler PC1 and a first end of the fifth resistor R5, respectively. The second end of the fifth resistor R5 is connected to the second end of the first capacitor C1, the second end of the second capacitor C2, and the output end (pe_loss) of the isolation conversion module, respectively. The first end of the first capacitor C1 and the first end of the second capacitor C2 are connected to the signal ground SGND.

For example, the first preset threshold may be 3V, the second preset threshold may be 3V, and the third preset threshold may be 1V. The present application is not limited thereto.

In another embodiment of the present application, as shown in fig. 2, another charging post ground impedance detection circuit is disclosed. The circuit further comprises a main control module 23 on the basis of the embodiment. The signal sampling module 21, the isolation conversion module 22 and the main control module 23 are sequentially connected. The main control module 23 determines whether the ground impedance of the charging pile is abnormal according to the output voltage signal. For example, when the output voltage signal is greater than or equal to a first preset threshold, it is determined that the ground impedance is abnormal. And when the output voltage signal is smaller than a first preset threshold value, determining that the grounding impedance is normal. When the ground impedance is abnormal, the main control module 23 can control the display screen of the charging pile to output early warning information, namely, giving related warning. Or the main control module 23 controls the charging pile to stop charging. The main control module 23 may be an MCU unit.

For example, the model of the master control module may be HC32F460PETB-LQFP100. The present application is not limited thereto.

The working principle of the charging pile grounding impedance detection circuit is described as follows:

the primary side of the optocoupler PC1 passes through the first diode D1, the second diode D2, the primary side of the optocoupler PC1, the first resistor R1, the second resistor R2, the third resistor R3 and PE to form a passage, and a detection current signal is generated. The pe_loss output is low, transmitted through optocoupler PC 1. The low level may be, for example, 0.6V (as shown in fig. 3). And the main control module periodically detects the level signal of PE_loss, and determines that the grounding impedance of the charging pile is normal when the level signal is smaller than the first preset threshold value.

When the primary side of the optocoupler PC1 cannot form a channel, no current signal is detected, and the optocoupler PC1 does not transmit, so that the pe_loss output is at a high level, that is, a power supply voltage, for example, the power supply voltage may be at a level of 3.3V. And the main control module periodically detects a level signal of PE_loss, and when the level signal is larger than the first preset threshold value, the ground impedance of the charging pile is determined to be abnormal. For example, the first preset threshold may be 3V.

Fig. 4 is a schematic diagram of a charging pile connection according to an embodiment of the utility model. Wherein, K1 and K2 are both switches. For example, when the ground impedance is abnormal, the main control module can control the switches K1 and K2 to be disconnected, namely, the charging pile is controlled to stop charging. The charging pile grounding impedance detection circuit disclosed in any of the embodiments of the present utility model is applied to the charging pile of the drawing. The OBC is an on-board charger.

Referring to fig. 4, the signal sampling modules are connected to the live, neutral and PE ground of the power grid, respectively. The main control module is respectively connected with the switches K1 and K2. The switch K1 and the OBC are respectively connected to the live wire output end L_out of the charging pile, and the switch K2 and the OBC are respectively connected to the zero line output end N_out of the charging pile. The OBC is also connected to PE ground. In this embodiment, the isolation conversion module and the master control module are respectively connected to the signal ground SGND. The output end of the detection circuit can be prevented from generating coupling voltage to the PE end, and the safety performance of the charging pile is improved.

In summary, the charging pile grounding impedance detection circuit provided by the utility model has at least the following advantages:

the charging pile grounding impedance detection circuit disclosed by the embodiment acquires input voltage signals of the zero line and the live line of the power grid through the signal sampling module, converts the input voltage signals to obtain output voltage signals, and can determine whether the grounding impedance is abnormal or not according to the output voltage signals, so that the safety of the charging pile is improved; the circuit is composed of a common resistor, a common capacitor, a common diode and a common optocoupler, and has the advantages of small occupied volume, low cost and high practicability.

In the description of the present utility model, it should be understood that the terms "bottom," "longitudinal," "transverse," "upper," "lower," "front," "rear," "vertical," "horizontal," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate description of the present utility model and simplify the description, and do not indicate or imply that the structures or elements being referred to must have a particular orientation, be configured and operated in a particular orientation, and thus should not be construed as limiting the present utility model. Furthermore, features defining "first", "second" may include one or more such features, either explicitly or implicitly. In the description of the present utility model, unless otherwise indicated, the meaning of "a plurality" means two or more, and the meaning of "a number" means one or more.

In the description of the present specification, reference is made to the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a particular example," etc., meaning that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the utility model. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing is a further detailed description of the utility model in connection with the preferred embodiments, and it is not intended that the utility model be limited to the specific embodiments described. It will be apparent to those skilled in the art that several simple deductions or substitutions may be made without departing from the spirit of the utility model, and these should be considered to be within the scope of the utility model.

Claims

1. The charging pile grounding impedance detection circuit is characterized by comprising a signal sampling module and an isolation conversion module which are connected;

2. The charging pile grounding impedance detection circuit of claim 1, further comprising a main control module, wherein the main control module is connected with the isolation conversion module, and wherein the main control module determines whether the charging pile grounding impedance is abnormal according to the output voltage signal.

3. The circuit of claim 1, wherein the second pin and the third pin of the optocoupler are grounded respectively, and the fourth pin of the optocoupler is connected to a power supply voltage.

4. The charging stake ground impedance detection circuit as recited in claim 1, wherein the signal sampling module includes a first diode and a second diode, the first diode being connected to a hot line of a power grid and the second diode being connected to a neutral line of the power grid.

5. The circuit of claim 3, wherein the signal sampling module further comprises a plurality of resistors connected in series, a first end formed by the plurality of resistors connected in series is grounded, and a second end formed by the plurality of resistors is connected to a second pin of the optocoupler.

6. The ground impedance detection circuit of claim 3, wherein the isolation conversion module further comprises at least one capacitor, a first end of the capacitor is connected to the third pin of the optocoupler and the ground, and a second end of the capacitor is connected to the fourth pin of the optocoupler and the output end of the isolation conversion module, respectively.

7. The circuit of claim 3, wherein the isolation conversion module further comprises a fourth resistor, a first end of the fourth resistor is connected to a power voltage, and a second end of the fourth resistor is connected to a fourth pin of the optocoupler and an output end of the isolation conversion module, respectively.

8. The circuit of claim 3, wherein the isolation conversion module further comprises a fifth resistor, a first end of the fifth resistor is connected to the power supply voltage and a fourth pin of the optocoupler, and a second end of the fifth resistor is connected to an output end of the isolation conversion module.

9. The circuit of claim 3, wherein the signal sampling module further comprises a first resistor, a second resistor, and a third resistor connected in series, wherein a first end formed by the first resistor, the second resistor, and the third resistor connected in series is grounded, and a second end formed by the first resistor, the second resistor, and the third resistor are connected to a second pin of the optocoupler.

10. The circuit of claim 6, wherein the isolation conversion module comprises a first capacitor and a second capacitor connected in parallel, a first end formed by connecting the first capacitor and the second capacitor in parallel is respectively connected to a third pin of the optocoupler and the ground, and a second end formed by connecting the first capacitor and the second capacitor in parallel is respectively connected to a fourth pin of the optocoupler and an output end of the isolation conversion module.