A signal acquisition circuit, device, and charging system

Abstract

This application discloses a signal acquisition circuit, device, and charging system. The signal acquisition circuit includes a filtering module, an amplification module, an analog-to-digital converter (ADC), and a controller. A control guide CP transmission line is connected to the input terminal of the filtering module, and the low-pass output terminal of the filtering module is connected to the amplification module. The filtering module performs low-pass filtering on the CP signal and outputs a low-frequency CP signal. The first output terminal of the amplification module is connected to the controller, its first level terminal is connected to the first level output terminal of the controller, its second level terminal is connected to the second level output terminal of the controller, and its second output terminal is connected to the input terminal of the ADC. The output terminal of the ADC is communicatively connected to the controller. The aim is to solve the technical problem of obtaining an accurate voltage value in CP signal acquisition.

Description

Technical Field

[0001] This application relates to the field of new energy vehicle charging technology, and in particular to a signal acquisition circuit, device and charging system. Background Technology

[0002] With the increasing popularity of new energy vehicles, charging piles for these vehicles are small in size, flexible in installation, and low in construction cost, making them suitable for installation in residential communities, large parking lots, hospitals, shopping malls, and other locations. Among these, the Control Pilot (CP) signal is one of the core signals for ensuring safe and orderly charging of new energy vehicles. The voltage changes of the CP signal contain crucial information such as the charging connection status and charging current requirements; therefore, acquiring the voltage value of the CP signal is a vital part of the charging system control within the charging pile.

[0003] Generally, the CP signal acquisition circuit is based on a voltage divider resistor network and an operational amplifier to acquire the pulse width modulation (PWM) voltage in the CP signal. It's important to note that the design focus of the CP signal acquisition circuit is to match the acquired voltage value with the CP voltage range specified in the charging standard, thereby determining the current charging state of the electric vehicle. It's worth noting that existing CP signal acquisition circuits, after acquiring the voltage signal, use an operational amplifier with a large range to determine the voltage value. This voltage determination method cannot accurately measure the voltage value and may introduce voltage errors. Therefore, obtaining an accurate voltage value is a crucial technical problem to be solved in CP signal acquisition.

[0004] The above content is only used to help understand the technical solution of this application and does not represent an admission that the above content is prior art. Utility Model Content

[0005] The main purpose of this application is to provide a signal acquisition circuit, device and charging system, which aims to solve the technical problem of how to obtain accurate voltage values ​​in CP signal acquisition.

[0006] To achieve the above objectives, this application provides a signal acquisition circuit, including: a filtering module, an amplification module, an analog-to-digital conversion module, and a controller.

[0007] The control guide CP transmission line is connected to the input terminal of the filter module, and the low-pass output terminal of the filter module is connected to the amplification module; the filter module is used to perform low-pass filtering on the CP signal and output a low-frequency CP signal.

[0008] The first output terminal of the amplifier module is connected to the controller, the first level terminal is connected to the first level output terminal of the controller, the second level terminal is connected to the second level output terminal of the controller, the second output terminal is connected to the input terminal of the analog-to-digital converter module, and the output terminal of the analog-to-digital converter module is connected to the controller for communication.

[0009] The controller is used to output a first strobe signal through a first level output terminal and a second strobe signal through a second level output terminal, determine the DC voltage value or the amplitude of pulse width modulation (PWM) in the CP signal based on the received first digital signal, and determine the frequency and duty cycle of the PWM signal in the CP signal based on the received second digital signal.

[0010] The amplification module is used to transmit a second digital signal through a first output terminal, transmit an analog signal through a second output terminal, and adjust the gain in response to a first strobe signal and a second strobe signal.

[0011] The analog-to-digital converter module is used to convert the received analog signal into a first digital signal and then output it.

[0012] Optionally, the signal acquisition circuit may also include a power line communication (PLC) acquisition module.

[0013] The high-pass output of the filtering module is connected to the PLC acquisition module. The filtering module performs high-pass filtering on the CP signal and then outputs a high-frequency CP signal to the PLC acquisition module. The PLC acquisition module determines the high-frequency PLC signal within the CP signal based on the received high-frequency CP signal.

[0014] Optionally, the amplification module includes: a voltage divider unit, a comparator unit, and an amplification unit.

[0015] The input terminal of the voltage divider unit is connected to the low-pass output terminal of the filter module, and the output terminal is connected to the input terminal of the comparator unit and the input terminal of the amplifier unit, respectively. The voltage divider unit is used to limit the low-frequency CP signal output from the low-pass filter path before outputting it.

[0016] The output of the comparator unit is connected to the controller as the first output of the amplification module. The reference voltage terminal of the comparator unit is connected to the reference voltage signal on the acquisition circuit. The comparator unit outputs a second digital signal based on the comparison result between the limited low-frequency CP signal and the reference voltage.

[0017] The two input terminals of the amplification unit serve as the first and second level terminals of the amplification module, respectively, and the output terminal serves as the second output terminal connected to the input terminal of the analog-to-digital conversion module. The amplification unit adjusts its gain in response to the first and second strobe signals.

[0018] Optionally, the filtering module includes: a high-pass filtering path formed by a first capacitor and a first resistor, and a low-pass filtering path formed by a first inductor, a second resistor, and a second capacitor.

[0019] The first terminal of the first capacitor and the first terminal of the second resistor are electrically connected to form the input terminal of the filter module.

[0020] The second terminal of the first capacitor is electrically connected to the first terminal of the first resistor to form the high-pass output terminal of the filter module, and the second terminal of the first resistor is grounded.

[0021] The second end of the second resistor is electrically connected to the first end of the second capacitor to form the low-pass output terminal of the filter module. The second end of the second capacitor is grounded, and the first inductor is connected in parallel across the two ends of the second resistor.

[0022] Optionally, the amplification unit includes: a first switch, a third resistor, a second switch, a fourth resistor, and an operational amplifier group.

[0023] The level input terminal of the first switch is used as the first level terminal, the normally open terminal is connected to the first feedback gain terminal of the operational amplifier group, the common terminal is connected to the first terminal of the third resistor, and the second terminal of the third resistor is connected to the second feedback gain terminal of the operational amplifier group. The level input terminal of the second switch serves as the second level terminal, the normally open terminal is connected to the first feedback gain terminal of the operational amplifier group, the common terminal is connected to the first terminal of the fourth resistor, and the second terminal of the fourth resistor is connected to the second feedback gain terminal of the operational amplifier group.

[0024] The non-inverting input of the operational amplifier group is connected to the output of the voltage divider unit, the inverting input is connected to the ground point, and the output is connected as the second output to the output of the analog-to-digital converter unit.

[0025] Optionally, the operational amplifier group includes: a first operational amplifier, a first feedback resistor, a second operational amplifier, a second feedback resistor, a third feedback resistor, a third operational amplifier, a fifth resistor, a sixth resistor, a seventh resistor, and an eighth resistor.

[0026] The non-inverting input of the first operational amplifier serves as the inverting input of the operational amplifier group, and its output is connected to the inverting input of the third operational amplifier through the fifth resistor. The first feedback resistor is connected in series between the inverting input and the output of the first operational amplifier.

[0027] The non-inverting input of the second operational amplifier serves as the non-inverting input of the operational amplifier group, and its output is connected to the non-inverting input of the third operational amplifier through the sixth resistor. The second feedback resistor is connected in series between the inverting input and the output of the second operational amplifier.

[0028] The third feedback resistor is connected in series between the inverting input terminal and the output terminal of the third operational amplifier, and the output terminal of the third operational amplifier serves as the output terminal of the operational amplifier group.

[0029] The first end of the seventh resistor is connected to the non-inverting input of the third operational amplifier, and the second end is connected to the reference voltage terminal of the operational amplifier group.

[0030] The eighth resistor is connected in series with the inverting input of the first operational amplifier and the inverting input of the second operational amplifier. The first end of the eighth resistor serves as the first feedback gain terminal of the operational amplifier group, and the second end serves as the second feedback gain terminal of the operational amplifier group.

[0031] Optionally, the PLC acquisition unit includes a fourth operational amplifier and a PLC acquisition unit. The non-inverting input of the fourth operational amplifier is connected to the high-pass output of the filter module, and the output of the fourth operational amplifier is connected to the inverting input of the fourth operational amplifier and the PLC acquisition unit, respectively.

[0032] The fourth operational amplifier is used to stably transmit the received high-frequency CP signal to the PLC acquisition unit. The PLC acquisition unit is used to determine the high-frequency PLC signal in the CP signal through the high-frequency CP signal.

[0033] In addition, this application also provides a signal acquisition device, including the signal acquisition circuit of the first aspect and any possible embodiment thereof.

[0034] In addition, this application also provides a charging system, including at least two power modules, a controller, a power distribution device, and at least one charging interface; the power distribution device includes the signal acquisition circuit described in the first aspect and any of its optional embodiments.

[0035] The power distribution device is connected to the controller, each power module, and each charging interface.

[0036] The power module is used to convert AC power from the grid into DC power to supply the charging interface.

[0037] The controller is used to obtain the power demand of each charging interface and generate scheduling instructions based on the connection relationship of the controllable switches in the power distribution device and the power demand.

[0038] The power distribution device is used to control the opening or closing of the controllable switch according to the scheduling instructions, so as to distribute the output power of each power module to each charging interface.

[0039] The signal acquisition circuit provided in this application has an amplification module with two level control terminals. The controller can adjust the gain of the amplification module using a first selection signal and a second selection signal to achieve different degrees of voltage amplification. It is understandable that, taking the measurement of CP voltage as an example, for the same voltage value, different voltage measurement ranges will affect the measurement accuracy. This application achieves the technical objective of changing the measurement range by changing the gain. Therefore, the signal acquisition method using the embodiments of this application can determine an accurate voltage value based on the acquired signal. Attached Figure Description

[0040] Figure 1 A schematic diagram of a CP signal acquisition circuit in a national standard AC charging scenario provided in this application embodiment; Figure 2 A schematic diagram of a CP signal acquisition circuit in a European standard AC charging scenario is provided for an embodiment of this application; Figure 3 A schematic diagram of a CP signal acquisition circuit in a European standard DC charging scenario is provided for an embodiment of this application; Figure 4A This application provides a schematic diagram of a signal acquisition circuit structure. Figure 4B This is a schematic diagram of another signal acquisition circuit structure provided in an embodiment of this application; Figure 5 This is a schematic diagram of the circuit structure of the filtering module in the signal acquisition circuit provided in the embodiments of this application; Figure 6 This is a schematic diagram of another signal acquisition circuit structure provided in an embodiment of this application; Figure 7 This is a schematic diagram of the circuit structure of the amplification unit in the signal acquisition circuit provided in the embodiments of this application; Figure 8 This application provides a schematic diagram of an equivalent circuit structure of an operational amplifier group. Figure 9 This is a schematic diagram of the voltage divider unit and amplification unit circuit structure in the signal acquisition circuit provided in the embodiments of this application; Figure 10 A schematic diagram of the circuit structure of the PLC acquisition module in the signal acquisition circuit provided in the embodiments of this application; Figure 11 A flowchart of a signal acquisition method provided in an embodiment of this application; Figure 12 This is a flowchart of another signal acquisition method provided in an embodiment of this application; Figure 13 This is a schematic diagram of a charging system provided in an embodiment of this application; Figure 14 This is a schematic diagram of the structure of a signal acquisition device provided in an embodiment of this application.

[0041] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0042] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present utility model, and not all of them. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0043] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0044] In this utility model, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0045] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0046] As is well known, when an electric vehicle is charging, the CP signal is a voltage signal generated on the CP line, which is an important signal for achieving a safe handshake between the power supply equipment (or charging pile) and the electric vehicle. The CP signal is a composite signal including DC voltage and PWM signal. In the non-charging stage, the CP signal is a pure DC voltage signal, while in the charging stage, the CP signal is a composite signal including DC bias voltage and PWM signal. Throughout the entire charging process of the electric vehicle, the controller needs to monitor the CP signal.

[0047] Electric vehicles can send commands to the charging station by changing the voltage or PWM signal in the CP signal (this command could be a request to stop charging, a fault report, etc.). The charging station can determine whether an electric vehicle is connected and whether to charge it based on the voltage or PWM signal in the CP signal. For example, according to national standards, a voltage level of 12V in the CP signal indicates that the charging gun is not plugged into the electric vehicle socket; a voltage level of 9V indicates that the charging gun is plugged into the electric vehicle socket; and a voltage level of 6V indicates that the electric vehicle is ready to charge and requests AC power output. Therefore, accurate acquisition of the voltage signal in the CP signal is a crucial aspect of the charging control system design in a charging station.

[0048] In other applications, different charging standards require corresponding CP signal acquisition circuits. In other words, CP signal acquisition circuits are not interchangeable across different charging standards.

[0049] For example, please refer to Figure 1 This is a schematic diagram of CP signal acquisition in a national standard AC charging scenario provided by an embodiment of this application. Figure 1 As shown, one end of the acquisition circuit is connected to the CP signal line for acquiring the CP signal, and the other end is connected to the PE line for grounding. In the national standard for AC charging, the CP signal acquisition circuit can be composed of a voltage divider network combined with an operational amplifier. This CP signal acquisition circuit can acquire the PWM signal within the CP signal. The key design feature of this circuit is accurately identifying the voltage value in the CP signal as specified by the national standard. For example, the national standard specifies charging states for CP signal voltage values ​​of 12V, 9V, and 6V. Accurately acquiring the voltage value in the CP signal helps the charging station determine the electric vehicle's status based on the CP signal.

[0050] For another example, please refer to Figure 2 This is a schematic diagram of CP signal acquisition in a European standard AC charging scenario, provided as an embodiment of the application. Figure 2As shown, one end of the acquisition circuit is connected to the CP signal line for acquiring the CP signal, and the other end is connected to the PE line for grounding. In the European standard AC charging standard, the CP signal is superimposed with a PLC carrier signal. Under this standard, the frequency of the PLC carrier signal is typically 13.56MHz. Therefore, the CP signal acquisition circuit in the above example cannot be applied to the European standard AC charging standard. In some implementations, the CP signal acquisition circuit can use a low-pass filter structure to filter out the high-frequency carrier signal, and then perform voltage sampling through an ADC module.

[0051] Additionally, please refer to Figure 3 This is a schematic diagram of CP signal acquisition under a European standard DC charging scenario provided in an embodiment of this application. Figure 3 As shown, one end of the acquisition circuit is connected to the CP signal line for acquiring the CP signal, and the other end is connected to the PE line for grounding. In some European standard DC charging scenarios, the CP signal acquisition circuit may involve acquiring CP signals with higher voltage values ​​and more complex state switching logic. In some practical applications, the CP signal acquisition circuit may be designed using a wide-range operational amplifier to build the amplification circuit, so that the CP signal acquisition circuit can cover a wider voltage variation range.

[0052] It is understandable that these CP signal acquisition circuits are designed for a single charging standard scenario. Their circuits are often only applicable to the current specific charging standard scenario and are difficult to apply to other charging standard scenarios, resulting in low versatility.

[0053] Based on this, embodiments of this application provide a signal acquisition method and a signal acquisition circuit. The signal acquisition method provided in this application can be applied to the signal acquisition circuit. First, based on the signal acquisition circuit, when implementing the signal acquisition method, the signal measurement range can be adjusted by adjusting the gain in the signal acquisition circuit, thereby providing an accurate way to measure voltage values. The signal acquisition circuit includes a filtering module, an amplification module, and an analog-to-digital conversion module. Through filtering by the filtering module, it can be determined whether there is a CP signal in the acquired signal. Furthermore, the amplification module and the analog-to-digital conversion module amplify and calculate the gain of the acquired signal to determine the voltage value in the CP signal.

[0054] Secondly, in the signal acquisition circuit provided in this application embodiment, the signal acquisition circuit may include a PLC acquisition module, and the filtering module may include a low-pass filter path and a high-pass filter path. The low-pass filter path is used to pass low-frequency signals, and the high-pass filter is used to pass high-frequency signals. The high-frequency PLC signal is acquired by the PLC acquisition module. In this way, if the CP signal includes a high-frequency PLC signal, the high-frequency PLC signal can also be filtered. This improves the compatibility of the signal acquisition circuit, allowing it to be applied to other charging standard scenarios.

[0055] The signal acquisition circuit provided in the embodiments of this application will be described in detail first, and then the signal acquisition method applied to the signal acquisition circuit will be described in detail.

[0056] Please refer to Figure 4A This is a block diagram of a signal acquisition circuit provided in an embodiment of this application. Figure 4A As shown, the signal acquisition circuit includes: a filtering module 41, an amplification module 42, an analog-to-digital conversion module 43, and a controller 44.

[0057] The CP signal transmission line is connected to the input terminal of the filter module 41, and the output terminal of the filter module 41 is connected to the amplification module 42. The first output terminal of the method module 42 is connected to the controller, the first level terminal is connected to the first level output terminal of the controller, the second level terminal is connected to the second level output terminal of the controller 44, and the second output terminal is connected to the input terminal of the analog-to-digital converter module 43. The output terminal of the analog-to-digital converter module 43 is communicatively connected to the controller 44.

[0058] The controller 44 transmits a first gating signal to the first level terminal and a second gating signal to the second level terminal. The amplifier module 42 adjusts its gain in response to the first and second gating signals. Here, gain adjustment refers to adjusting the impedance in the feedback circuit, thereby adjusting the measurement range of the input voltage.

[0059] For example, the first strobe signal includes a first high-level signal and a first low-level signal, and the second strobe signal includes a second high-level signal and a second low-level signal. These signals can form four signal combinations to enable the amplification module 42 to adjust four gain states.

[0060] In addition, to achieve compatibility in different charging standard scenarios, a PLC acquisition module is added to the signal acquisition circuit, and the filtering module 41 is set as a high-pass filter unit and a low-pass filter unit. The signal after high-pass filtering is transmitted to the PLC acquisition module, and the signal after low-pass filtering is transmitted to the amplification module 42.

[0061] Please refer to Figure 4B This is a block diagram of another signal acquisition circuit provided in an embodiment of this application. Figure 4B As shown, the signal acquisition circuit also includes a PLC acquisition module 45.

[0062] The filtering module 41 includes a high-pass filter unit and a low-pass filter unit. The high-pass output terminal of the filtering module 41 is connected to the PLC acquisition module 45, and the low-pass output terminal of the filtering module 41 is connected to the amplification module 42.

[0063] The PLC acquisition module is used to determine the high-frequency PLC signal in the CP signal based on the received high-frequency CP signal.

[0064] in, Figure 4B The signal acquisition circuit in the middle is based on Figure 4A Further explanation of the signal acquisition circuit, therefore, Figure 4B Zhongyu Figure 4A The connection relationships between identical modules will not be elaborated further.

[0065] Furthermore, the analog-to-digital converter module 43 is used to convert the received analog signal into a first digital signal and then output it. The controller 44 is used to determine the DC voltage value or the amplitude of the pulse width modulation (PWM) signal in the CP signal based on the received first digital signal, and to determine the frequency and duty cycle of the PWM signal in the CP signal based on the received second digital signal.

[0066] In the acquisition circuit provided in this application, the controller 44 can acquire the acquisition signal and perform simple data processing. Therefore, in the embodiments of this application, the controller 44 can be a microcontroller, such as a single-chip microcomputer, rather than a central processing unit (CPU) capable of handling complex calculations. This application does not limit the specific type of the controller 44.

[0067] When the signal acquisition circuit is applied to a standard AC charging scenario, the CP signal is acquired by the controller through the low-pass filter path of the filter module 41. When the signal acquisition circuit is applied to a standard European AC charging scenario, the high-frequency PLC signal in the CP signal can be acquired by the PLC acquisition module through the high-pass filter path of the filter module, and the PLC signal can be acquired by the controller through the low-pass filter path of the filter module 41. Additionally, the controller can send a first gating signal and a second gating signal to the amplification module to adjust the voltage measurement range, enabling the signal acquisition circuit to be applied to DC charging scenarios.

[0068] In other words, the signal acquisition circuit provided in this application embodiment can be applied to different charging standard scenarios, increasing the compatibility of the signal acquisition circuit. Furthermore, the controller can adjust the voltage measurement range through the control of the first and second strobe signals, ensuring sufficient measurement accuracy even when measuring small signal voltages.

[0069] In one possible implementation, the filtering module 41 includes a low-pass filter path and a high-pass filter path. For example... Figure 5 The diagram shows the circuit structure of the filter module 41. It includes a high-pass filter path formed by the first capacitor C1 and the first resistor R1, and a low-pass filter path formed by the first inductor L1, the second resistor R2, and the second capacitor C2.

[0070] The second terminal of the first capacitor C1 is electrically connected to the first terminal of the first resistor R1, forming the high-pass output terminal of the filter module 41. The second terminal of the first resistor R1 is grounded. The high-pass filter output path is used to output the high-frequency filtered signal CP1.

[0071] The second terminal of the second resistor R2 is electrically connected to the first terminal of the second capacitor C2, forming the low-pass output terminal of the filter module 41. The second terminal of the second capacitor C2 is grounded, and the first inductor L1 is connected in parallel across the two ends of the second resistor R2. The low-pass filter path is used to output the low-frequency filtered signal CP2.

[0072] After filtering the input CP signal, frequencies above 1MHz can pass through, while frequencies below 5kHz are blocked. R2, C2, and L2 form a low-pass filter, which allows the input CP signal to pass through frequencies below 5kHz while blocking frequencies above 1MHz.

[0073] Specifically, the amplification module 42 may further include a voltage divider unit 21, a comparator unit 22, and an amplification unit 23. The PLC acquisition module 45 may include a high-speed operational amplifier 51 and a PLC acquisition unit 52. Please refer to [reference needed]. Figure 6 This is a schematic block diagram of another signal acquisition circuit provided in an embodiment of this application.

[0074] The input terminal of the voltage divider unit 21 is connected to the low-pass output terminal of the filter module 41, and the output terminal is connected to the input terminal of the comparator unit 22 and the input terminal of the amplifier unit 23, respectively. The voltage divider unit 21 is used to limit the low-frequency CP signal output from the low-pass filter path before outputting it.

[0075] The output terminal of comparator unit 22 is connected to controller 44 as the first output terminal of amplifier module 42. The reference voltage terminal of comparator unit 22 is connected to the reference voltage signal on the acquisition circuit. Comparator unit 22 outputs a second digital signal based on the comparison result between the limited low-frequency CP signal and the reference voltage.

[0076] For example, comparator unit 22 can be a comparator. The reference voltage terminal of the comparator is connected to the reference voltage signal on the acquisition circuit. When the output signal of voltage divider unit 21 is transmitted to the comparator, the comparator can compare the output signal with the reference voltage value. If the reference voltage value is less than the output signal voltage value, the comparator outputs a second digital signal "1" to the controller; if the reference voltage value is greater than the output signal voltage value, the comparator outputs a second digital signal "0" to the controller. Therefore, the controller can obtain a series of signals consisting of "1" and "0" through the comparator.

[0077] The two level signal input terminals of the amplification unit 23 are respectively used as the first level terminal and the second level terminal of the amplification module 42, and the output terminal is used as the second output terminal and connected to the input terminal of the analog-to-digital conversion module 43. The amplification unit 23 adjusts its gain in response to the first strobe signal and the second strobe signal.

[0078] In another possible implementation, the structural block diagram of the amplification unit 22 is shown as follows: Figure 7 As shown. The amplification unit 22 includes: a first switch K1, a third resistor R3, a second switch K2, a fourth resistor R4, and an operational amplifier group A0.

[0079] The first switch K1 can be a switch module, which includes a level input terminal IN, a normally open terminal NO, a common terminal COM, a ground terminal GND, and a voltage terminal V+. For example... Figure 7 As shown, IN of the first switch K1 is used as the first level terminal, NO, the normally open terminal is connected to the first feedback gain terminal of the operational amplifier group A0, COM, the common terminal is connected to the first terminal of the third resistor R3, and the second terminal of the third resistor R3 is connected to the second feedback gain terminal of the operational amplifier group A0.

[0080] The second switch K2 can be a switch module. Similarly, this switch module includes a level input terminal IN, a normally open terminal NO, a common terminal COM, a ground terminal GND, and a voltage terminal V+. K2's IN serves as the second level terminal, the normally open terminal NO is connected to the first feedback gain terminal of operational amplifier group A0, the common terminal COM is connected to the first terminal of the fourth resistor R4, and the second terminal of the fourth resistor R4 is connected to the second feedback gain terminal of operational amplifier group A0.

[0081] An op-amp group can be composed of a single op-amp chip, such as Figure 7 As shown, the operational amplifier chip includes a non-inverting input terminal V+IN, an inverting input terminal V-IN, a first feedback terminal RG1, a second feedback terminal RG2, a current positive input terminal V+, a current negative input terminal V-, an output terminal Vo, and a reference voltage terminal Ref. The non-inverting input terminal V+IN of operational amplifier group A0 is connected to the output terminal of voltage divider unit 21, the inverting input terminal V-IN is connected to ground, and the output terminal Vo is connected as the second output terminal to the output terminal of analog-to-digital converter unit 43.

[0082] In one possible implementation, the third resistor R3 serves to increase the impedance of the feedback loop. Therefore, in a specific configuration, the third resistor R3 can also be composed of two resistors connected in parallel, such as resistors R3-1 and R3-2 connected in parallel. The specific circuit structure here is merely an example and is not intended to be specific.

[0083] It should be understood that the amplification unit 22 can isolate the impedance of the input signal and amplify the input signal. It can also adjust the impedance of the feedback circuit under the action of the first and second gating signals of the controller 44 to achieve the purpose of adjusting the feedback, thereby enabling accurate measurement of voltage values ​​of different ranges.

[0084] Specifically, the equivalent circuit diagram of op-amp group A0, as an op-amp chip, can be found by referring to... Figure 8 This is a schematic diagram of the equivalent circuit structure of an operational amplifier chip provided in an embodiment of this application. Figure 8 As shown, the operational amplifier group includes: first operational amplifier A1, first feedback resistor RE1, second operational amplifier A2, second feedback resistor RE2, third feedback resistor RE3, third operational amplifier A3, fifth resistor R5, sixth resistor R6, seventh resistor R7 and eighth resistor R8.

[0085] The non-inverting input of the first operational amplifier A1 serves as the inverting input of the operational amplifier group, and its output is connected to the inverting input of A3 via R5. The first feedback resistor RE1 is connected in series between the inverting input and the output of the first operational amplifier A1.

[0086] The non-inverting input of the second operational amplifier A2 serves as the non-inverting input of the operational amplifier group, and its output is connected to the non-inverting input of A3 through the sixth resistor R6. The second feedback resistor RE2 is connected in series between the inverting input and the output of the second operational amplifier A2.

[0087] The third feedback resistor RE3 is connected in series between the inverting input terminal of the third operational amplifier A3 and the output terminal of the third operational amplifier A3. The output terminal of the third operational amplifier A3 serves as the output terminal of operational amplifier group A0.

[0088] The first end of the seventh resistor R7 is connected to the non-inverting input of the third operational amplifier A3, and the second end is connected to the reference voltage terminal of the operational amplifier group A0.

[0089] The eighth resistor R8 is connected in series with the inverting input terminal of the first operational amplifier A1 and the inverting input terminal of the second operational amplifier A2. The first end of the eighth resistor R8 serves as the first feedback terminal RG1 of the operational amplifier group A0, and the second end serves as the second feedback point RG2 of the operational amplifier group A0.

[0090] Specifically, the voltage divider unit 21 can be formed by multiple resistors connected in series. Please refer to [reference needed]. Figure 9The circuit structure diagram of the voltage divider unit 21 and the amplifier unit 23 in the signal acquisition circuit is shown below. Figure 9 As shown, the voltage divider unit includes an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, and a seventeenth resistor R17. The eleventh resistor R11 is connected to the low-pass output of the filter module, and the eleventh, twelfth, and thirteenth resistors R13 are connected in series. The fourteenth resistor R14 is connected to the non-inverting input of amplifier group A0. The fifteenth, sixteenth, and seventeenth resistors R15, R16, and R17 are connected in series, with one end connected between the thirteenth and fourteenth resistors R13 and the other end grounded.

[0091] In the specific circuit connection shown in Figure 9, the inverting input terminal of op-amp group A0 can be connected to the ground terminal through resistor R18, and the low-pass output terminal of the filter module can also be connected to the ground point through the nineteenth resistor R19. The negative current input terminal V- of op-amp group A0 is connected to the -5V voltage terminal on the circuit board, and the -5V voltage terminal is grounded through two parallel capacitors C91 and C92.

[0092] The voltage terminal V+ of the first switch K1 is connected to the +5V voltage terminal on the circuit board, and the +5V voltage terminal is grounded through capacitor C93. The voltage terminal V+ of the second switch K2 can also be connected to the +5V voltage terminal on the circuit board in the same way.

[0093] In one possible implementation, the PLC acquisition unit includes a fourth operational amplifier A4 and a PLC acquisition unit. The circuit connection structure of its PLC acquisition unit is as follows: Figure 10 As shown, the non-inverting input of the fourth operational amplifier A4 is connected to the high-pass output of the filter module, and the output of the fourth operational amplifier A4 is connected to the inverting input of the fourth operational amplifier and the PLC acquisition unit, respectively.

[0094] The fourth operational amplifier, A4, is used to stably transmit the received high-frequency CP signal to the PLC acquisition unit. The PLC acquisition unit is used to determine the high-frequency PLC signal in the CP signal through the high-frequency CP signal.

[0095] Understandably, the fourth op-amp A4 is designed as a voltage follower, which can isolate the impedance of the CP1 signal. Due to the voltage follower mode of the fourth op-amp A4, the driving capability of the CP1 signal can be improved, so that the CP1 signal can be transmitted to the PLC acquisition unit.

[0096] It is understood that the above descriptions and specific circuit structures of each circuit module are for illustrative purposes only. In practical applications, the number and parameters of components can be adaptively increased or decreased according to design requirements. The embodiments of this application do not specifically limit the specific structure of each module circuit.

[0097] Based on the signal acquisition circuit described above, this application also provides a signal acquisition method, which can be applied to the aforementioned signal acquisition circuit. Please refer to... Figure 11 This is a flowchart of a signal acquisition method provided in an embodiment of this application. Figure 11 As shown, the method includes S01-S02.

[0098] It's important to understand that the aforementioned signal acquisition circuit can be applied to multiple charging standard scenarios. This example illustrates the signal acquisition method using an application scenario involving electric vehicles and charging stations. For instance, the signal acquisition circuit can be installed in a charging station, which provides power to electric vehicles.

[0099] Please note that this signal acquisition method can be applied to signal acquisition circuits that include a filtering module, an amplification module, an analog-to-digital converter (ADC), and a controller. These modules are connected sequentially, as detailed above. Figure 4A The diagram shows the signal acquisition circuit structure. This method uses a controller as the execution entity; the controller will be omitted in the following implementation steps.

[0100] S01: Continuously acquire the first digital signal sent by the analog-to-digital conversion module and the second digital signal sent by the first output terminal of the amplification module multiple times.

[0101] S02: Determine the pulse width modulation (PWM) signal in the CP signal based on multiple first digital signals and second digital signals, and determine the DC voltage value in the CP signal based on the first digital signals.

[0102] The analog-to-digital converter module is used to convert analog signals into first digital signals, and the controller can determine the voltage value obtained by the analog-to-digital converter unit based on the first digital signal.

[0103] Multiple second digital signals form a series of "0" and "1" signals. The controller can determine whether the voltage signal output by the voltage divider unit has changed based on the second digital signals. That is, if the second digital signals include low-level signals "0" and high-level signals "1", it means that the CP signal is a combination of DC bias signal and PWM signal; if the second digital signals only include high-level signals, it means that the CP signal only includes DC bias signal.

[0104] For example, if the charging gun of the charging station is plugged into an electric vehicle, but the charging station does not provide power to the electric vehicle, the CP signal is a stable 9V voltage value and there is no PWM signal. The controller can determine that the voltage value is 9V based on the first signal, and the multiple second digital signals are a series of digital "1".

[0105] In one possible implementation, in the specific implementation of S02 above, the amplitude of the PWM signal in the CP signal can be determined based on the first digital signal; if there is only a high-level signal among the multiple second digital signals, it is determined that the CP signal does not include the PWM signal; if there are both low-level and high-level signals among the multiple second digital signals, the duty cycle and frequency of the PWM signal are determined based on the multiple second digital signals.

[0106] For example, the second digital signal includes a low-level signal "0" and a high-level signal "1", and the low-level signal "0" and the high-level signal "1" appear in a periodic manner. For instance, after every 10 "1"s, 4 "0"s appear, and the 10 "1"s and 4 "0"s form a periodic signal. The duty cycle and frequency of the PWM signal are determined based on the periodic low-level signal "0" and high-level signal "1". Specifically, the time occupied by the low-level signal "0" and the high-level signal "1" in one cycle determines the frequency of the PWM signal, and the duty cycle of the PWM signal is the proportion of the high-level "1" in one cycle.

[0107] In some implementations, prior to S01, the controller can also send a first strobe signal and a second strobe signal to the amplification module. These signals indicate whether a feedback resistor is connected to the feedback circuit of the amplification unit within the amplification module. The connection of the feedback resistor affects the amplification factor of the amplification unit. In other words, whether or not a feedback resistor is connected to the amplification unit affects the voltage measurement accuracy of the signal acquisition circuit. By adjusting the feedback resistor to adjust the amplification factor of the amplification module, the technical objective of changing the voltage measurement accuracy is achieved.

[0108] In one possible implementation, when the signal acquisition method begins, the controller sends a first low-level signal and a second low-level signal (i.e., a first strobe signal and a second strobe signal) to the amplification module, causing the signal acquisition circuit to calculate the voltage value in the CP signal using a first range. After the controller calculates the voltage value of the CP signal, if the DC voltage value is within a preset first data range, the controller sends a first low-level signal and a second high-level signal to the amplification module (i.e., switching from the first range to the second range); if the DC voltage value is within a preset second data range, the controller sends a first high-level signal and a second low-level signal to the amplification module; if the DC voltage value is within a preset third data range, the controller sends a first high-level signal and a second high-level signal to the amplification module.

[0109] For example, prior to S01, the controller can also send a first low-level signal and a second low-level signal to the amplification module. The first low-level signal indicates that the first feedback circuit of the amplification module is connected to a feedback resistor, and the second low-level signal indicates that the second feedback circuit of the amplification module is connected to a feedback resistor. In this case, the measured voltage range of the amplification unit is -2.4V to +2.4V, and the output voltage range is -2.4V to +2.4V. If the controller determines, based on the first digital signal, that the voltage value output by the amplification unit is within a first value range (-100mV to +100mV), meaning the voltage value is small, then to obtain a more accurate voltage value, the first and second gating signals can be adjusted. For example, the controller sends a first low-level signal and a second high-level signal to the amplification module. The second high-level signal indicates that the second feedback circuit is connected to a feedback resistor. Therefore, the measured voltage range of the amplification unit is -100mV to +100mV, and the output voltage range is -2.4V to +2.4V.

[0110] For example, the second numerical range is -50mV to +50mV, and the third numerical range is -30mV to +30mV. If the controller determines from the first digital signal that the voltage value output by the amplification unit is within the second numerical range, it sends a first high-level signal and a second low-level signal to the amplification module; if the controller determines from the first digital signal that the voltage value output by the amplification unit is within the third numerical range, it sends a first high-level signal and a second high-level signal to the amplification module, wherein the first high-level signal is used to indicate that the first feedback circuit is connected to a feedback resistor.

[0111] For example, the specific gain adjustment method can be referred to in Table 1 below, which is the gain adjustment table for the amplification module.

[0112] Table 1: Amplifier Module Gain Adjustment Comparison Table

[0113] It should be noted that in the above comparison process, the system first determines whether the voltage value falls within the first numerical range. If the voltage value does, it then determines whether it falls within the second numerical range. If the voltage value does not fall within the first numerical range, the selection signal is not adjusted. Range 1 is the default range. Upon initial power-up of the signal acquisition circuit, the controller will control the amplification module to use range 1. After the controller assesses the acquired voltage value, if the voltage value falls within the range of other input ranges, it will adaptively adjust the range used.

[0114] For example, In one possible real-time approach, please refer to Figure 12This application provides a signal acquisition method, illustrating the control mode of the controller throughout the signal acquisition process. For example... Figure 12 As shown, the method includes S101-S112.

[0115] S101: Send a first low-level signal and a second low-level signal to the amplification module.

[0116] S102: Continuously acquire the first digital signal sent by the analog-to-digital conversion module and the second digital signal sent by the first output terminal of the amplification module multiple times.

[0117] S103: Determine whether the multiple second digital signals include periodic high-level signals and low-level signals; if yes, execute S104; if no, execute S112.

[0118] S104: Determine the frequency of the PWM signal based on the duration of the periodic low-level signal and the high-level signal.

[0119] S105: Determines the proportion of high-level signal in one cycle as the duty cycle of the PWM signal, and outputs the frequency and duty cycle of the PWM signal.

[0120] S106: Calculate the DC voltage value based on the first digital signal, and determine whether the DC voltage value is a value in the first data range; if yes, execute S107; if no, execute S109.

[0121] S107: Determine whether the DC voltage value is within the second numerical range; if yes, proceed to S108; if no, proceed to S110.

[0122] S108: Determine whether the DC voltage value is within the third value range; if yes, execute S110; if no, execute S111.

[0123] S109: Send a first low-level signal and a second high-level signal to the amplification module.

[0124] S110: Sends a first high-level signal and a second low-level signal to the amplification module.

[0125] S111: Send the first high-level signal and the second high-level signal to the amplification module.

[0126] S112: Calculate and output the DC voltage value.

[0127] One method for determining the DC voltage value is to divide the value of the first digital signal by the amplification factor of the amplification unit and then multiply the result by the voltage division factor of the voltage divider unit, and use the result as the DC voltage value in the CP signal.

[0128] It should be understood that when the CP signal includes the PWM signal, the calculated DC voltage value is the amplitude of the PWM signal in the CP signal.

[0129] This application also provides a signal acquisition device, including the aforementioned signal acquisition circuit. This signal acquisition device can be applied to charging piles for acquiring signals on the CP signal line.

[0130] This application also provides a charging system, please refer to... Figure 13 .like Figure 13 As shown, the charging system includes at least two power modules 110, a processor 130, a power distribution device 140, and at least one charging interface 120. The power distribution device 140 includes the signal acquisition circuit mentioned in the above embodiments. The power distribution device 140 is connected to the processor 130, each power module 110, and each charging interface 120. The power modules 110 convert AC power from the power grid into DC power to supply the charging interfaces. The processor 130 acquires the power demand of each charging interface 120 and generates scheduling commands based on the connection relationship of the controllable switches in the power distribution device 140 and the power demand. The power distribution device 140 controls the opening or closing of the controllable switches according to the scheduling commands to distribute the output power of each power module to each charging interface.

[0131] This application also provides a signal acquisition device, including... Figure 14 This is a schematic diagram of the structure of a signal acquisition device provided in an embodiment of this application, as shown below. Figure 14 As shown, the signal acquisition device 500 may include: a processor 510, a communication interface 520, a memory 530, and a communication bus 540. The processor 510, communication interface 520, and memory 530 communicate with each other via the communication bus 540. The processor 510 can call logical instructions stored in the memory 530 to execute the aforementioned method.

[0132] Furthermore, the logical instructions in the aforementioned memory 530 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this utility model, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this utility model. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0133] This application also provides a computer storage medium that includes computer instructions. When the computer instructions are executed on the processing device, the processing device can perform the method steps described in the method embodiments.

[0134] The embodiments also provide a computer program product that, when run on a processing device, enables the processing device to execute the method steps described in the above method embodiments.

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A signal acquisition circuit, characterized by comprising: include: Filtering module, amplification module, analog-to-digital conversion module, and controller; The control guide CP transmission line is connected to the input terminal of the filter module, and the low-pass output terminal of the filter module is connected to the amplification module; the filter module is used to perform low-pass filtering on the CP signal and then output a low-frequency CP signal to the amplification module. The amplification module has a first output terminal connected to the controller, a first level terminal connected to the first level output terminal of the controller, a second level terminal connected to the second level output terminal of the controller, and a second output terminal connected to the input terminal of the analog-to-digital converter module. The output terminal of the analog-to-digital converter module is communicatively connected to the controller. The controller is configured to output a first strobe signal through the first level output terminal and a second strobe signal through the second level output terminal, determine the DC voltage value or the amplitude of pulse width modulation (PWM) in the CP signal based on the received first digital signal, and determine the frequency and duty cycle of the PWM signal in the CP signal based on the received second digital signal. The amplification module is used to transmit the second digital signal through the first output terminal, transmit the analog signal through the second output terminal, and adjust the gain in response to the first strobe signal and the second strobe signal; The analog-to-digital converter module is used to convert the received analog signal into the first digital signal and then output it.

2. The acquisition circuit according to claim 1, characterized in that, The acquisition circuit also includes: a power line carrier communication PLC acquisition module; The high-pass output terminal of the filtering module is connected to the PLC acquisition module. The filtering module is used to perform high-pass filtering on the CP signal and then output a high-frequency CP signal to the PLC acquisition module. The PLC acquisition module is used to determine the high-frequency PLC signal in the CP signal based on the received high-frequency CP signal.

3. The acquisition circuit according to claim 1 or 2, characterized in that, The amplification module includes: a voltage divider unit, a comparator unit, and an amplification unit; The input terminal of the voltage divider unit is connected to the low-pass output terminal of the filter module, and the output terminal is connected to the input terminal of the comparator unit and the input terminal of the amplifier unit, respectively. The voltage divider unit is used to limit the low-frequency CP signal output from the low-pass filter path before outputting it. The output terminal of the comparator unit is connected to the controller as the first output terminal of the amplification module. The reference voltage terminal of the comparator unit is connected to the reference voltage signal on the acquisition circuit. The comparator unit outputs the second digital signal based on the comparison result between the limited low-frequency CP signal and the reference voltage. The two level signal input terminals of the amplification unit serve as the first level terminal and the second level terminal of the amplification module, respectively, and the output terminal serves as the second output terminal connected to the input terminal of the analog-to-digital conversion module. The amplification unit adjusts its gain in response to the first strobe signal and the second strobe signal.

4. The signal acquisition circuit according to claim 1 or 2, characterized in that, The filtering module includes: a high-pass filtering path formed by a first capacitor and a first resistor, and a low-pass filtering path formed by a first inductor, a second resistor, and a second capacitor; The first terminal of the first capacitor and the first terminal of the second resistor are electrically connected to form the input terminal of the filter module. The second terminal of the first capacitor is electrically connected to the first terminal of the first resistor to form the high-pass output terminal of the filter module, and the second terminal of the first resistor is grounded. The second end of the second resistor is electrically connected to the first end of the second capacitor to form the low-pass output terminal of the filter module. The second end of the second capacitor is grounded, and the first inductor is connected in parallel across the two ends of the second resistor.

5. The signal acquisition circuit according to claim 3, characterized in that, The amplification unit includes: a first switch, a third resistor, a second switch, a fourth resistor, and an operational amplifier group; The level input terminal of the first switch serves as the first level terminal, the normally open terminal is connected to the first feedback gain terminal of the operational amplifier group, the common terminal is connected to the first terminal of the third resistor, and the second terminal of the third resistor is connected to the second feedback gain terminal of the operational amplifier group. The level input terminal of the second switch serves as the second level terminal, the normally open terminal is connected to the first feedback gain terminal of the operational amplifier group, the common terminal is connected to the first terminal of the fourth resistor, and the second terminal of the fourth resistor is connected to the second feedback gain terminal of the operational amplifier group. The non-inverting input terminal of the operational amplifier group is connected to the output terminal of the voltage divider unit, the inverting input terminal is connected to the ground point, and the output terminal is connected to the output terminal of the analog-to-digital converter unit as the second output terminal.

6. The signal acquisition circuit according to claim 5, characterized in that, The operational amplifier group includes: a first operational amplifier, a first feedback resistor, a second operational amplifier, a second feedback resistor, a third feedback resistor, a third operational amplifier, a fifth resistor, a sixth resistor, a seventh resistor, and an eighth resistor; The non-inverting input terminal of the first operational amplifier serves as the inverting input terminal of the operational amplifier group, and the output terminal is connected to the inverting input terminal of the third operational amplifier through the fifth resistor. The first feedback resistor is connected in series between the inverting input terminal and the output terminal of the first operational amplifier. The non-inverting input terminal of the second operational amplifier serves as the non-inverting input terminal of the operational amplifier group, and the output terminal is connected to the non-inverting input terminal of the third operational amplifier through the sixth resistor. The second feedback resistor is connected in series between the inverting input terminal and the output terminal of the second operational amplifier. The third feedback resistor is connected in series between the inverting input terminal and the output terminal of the third operational amplifier, and the output terminal of the third operational amplifier serves as the output terminal of the operational amplifier group. The first end of the seventh resistor is connected to the non-inverting input of the third operational amplifier, and the second end is connected to the reference voltage terminal of the operational amplifier group. The eighth resistor is connected in series with the inverting input terminal of the first operational amplifier and the inverting input terminal of the second operational amplifier. The first end of the eighth resistor serves as the first feedback gain terminal of the operational amplifier group, and the second end serves as the second feedback gain terminal of the operational amplifier group.

7. The signal acquisition circuit according to claim 2, characterized in that, The PLC acquisition unit includes a fourth operational amplifier and a PLC acquisition unit; The non-inverting input of the fourth operational amplifier is connected to the high-pass output of the filter module, and the output of the fourth operational amplifier is connected to the inverting input of the fourth operational amplifier and the PLC data acquisition unit, respectively. The fourth operational amplifier is used to stably transmit the received high-frequency CP signal to the PLC acquisition unit. The PLC acquisition unit is used to determine the high-frequency PLC signal in the CP signal through the high-frequency CP signal.

8. A signal acquisition device, characterized in that, Includes the signal acquisition circuit as described in any one of claims 1-7.

9. A charging system, characterized in that, It includes at least two power modules, a controller, a power distribution device, and at least one charging interface; the power distribution device includes a signal acquisition circuit as described in any one of claims 1-7; The power distribution device is connected to the controller, each power module and each charging interface respectively. The power module is used to convert AC power from the power grid into DC power and supply it to the charging interface; The controller is used to obtain the power demand of each charging interface and generate scheduling instructions based on the connection relationship of the controllable switches in the power distribution device and the power demand. The power distribution device is used to control the opening or closing of the controllable switch according to the scheduling command, so as to distribute the output power of each power module to each charging interface.

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