A charging pilot signal processing method, device, product and medium

Abstract

A charging guide signal processing method, device, product and medium, relate to the field of new energy automobile power supply equipment. In view of the problem that the existing fixed RC filtering scheme causes CP signal edge tailing and waveform distortion, the method sends a reference pulse signal in the reference detection stage, collects the voltage extreme value on the CP signal line and calculates the overshoot amplitude value; According to this, the target switch combination of the digital adjustable impedance array is dynamically updated, until the overshoot amplitude value is less than or equal to the preset threshold, the control signal is locked, and the charging operation stage is entered. Whenever the edge jump is monitored, the hardware trigger circuit outputs a gate pulse with a preset time width, only during the pulse, the switch elements of the corresponding impedance branch are synchronously turned on, and after the end, the switch elements are turned off. The application realizes the instantaneous accurate absorption of ringing energy, avoids the continuous damping delay of voltage jump rate, guarantees the signal integrity, and further improves the accuracy and reliability of the charging state interaction.

Description

Technical Field

[0001] This application relates to the field of new energy vehicle power supply equipment (EVSE) technology, and in particular to a charging guidance signal processing method, device, product and medium. Background Technology

[0002] During AC charging, the AC charging station and the electric vehicle primarily communicate and configure power via the ControlPilot (CP) signal line. The CP signal typically uses a 1kHz PWM square wave for transmission. To adapt to more complex and diverse parking and charging scenarios, the charging gun cable length has gradually increased. However, the longer cable introduces parasitic inductance and capacitance, creating an equivalent transmission line effect. When the PWM wave of the CP signal experiences a rising or falling edge transition, severe high-frequency ringing occurs at the signal edge, affecting signal integrity.

[0003] To suppress high-frequency ringing at the edge of the CP signal, existing technologies typically employ a fixed passive RC low-pass filter circuit connected in parallel at the CP signal receiving front-end of the charging pile control board. Specifically, this solution mainly involves connecting a filter branch consisting of a resistor of fixed resistance and a capacitor of fixed capacitance in series between the CP signal line and the ground network. When an edge transition occurs on the CP signal line accompanied by high-frequency ringing, the capacitor bypasses and directs the transient high-frequency noise energy to ground. Simultaneously, the RC time constant and cutoff frequency of this filter branch are set according to the preset values ​​of the resistor and capacitor, thereby smoothing and clipping the transient overshoot waveform that exceeds the normal amplitude.

[0004] However, in high-power AC charging scenarios, the parasitic parameters of charging cables from different manufacturers, of different lengths, and with different degrees of aging are unknown and dynamically changing. If a large RC filter parameter is set to fully absorb the strong ringing caused by long cables, its large RC time constant will persist throughout the entire communication cycle, thus slowing down the transition rate of the PWM square wave edge, causing signal edge trailing and waveform distortion. This signal edge trailing and waveform distortion can cause the current pulse level to drop before the next transition cycle begins, increasing the decoding error rate of the on-board charger (OBC) for the PWM duty cycle and reducing the accuracy and reliability of charging status interaction. Summary of the Invention

[0005] This application provides a charging guidance signal processing method, device, product, and medium to improve the accuracy and reliability of charging status interaction in high-power AC charging scenarios.

[0006] Firstly, this application provides a charging guidance signal processing method applied to the main control unit of a charging guidance signal processing device. The charging guidance signal processing device further includes a hardware trigger circuit and a digitally adjustable impedance array. The digitally adjustable impedance array includes multiple impedance branches connected in parallel between the CP signal line and the ground terminal. Each impedance branch includes a series-connected impedance element and a switching element. The method includes: in the reference detection stage, outputting an initial multiplexing control signal to the hardware trigger circuit and sending a reference pulse signal through the CP signal line, wherein the target switching combination indicated by the initial multiplexing control signal is empty; in response to the edge transition of the reference pulse signal in the current cycle, acquiring the voltage extreme value on the CP signal line and calculating the overshoot amplitude value of the current cycle based on the voltage extreme value; when the overshoot amplitude value is greater than a preset overshoot amplitude value, the method provides a method for processing charging guidance signals. When the overshoot threshold is reached, the updated target switch combination is determined based on the overshoot amplitude value, and a multiplex control signal corresponding to the updated target switch combination is output to the hardware trigger circuit. The overshoot amplitude value is repeatedly calculated in each cycle of the reference detection phase. When the overshoot amplitude value is less than or equal to the preset overshoot threshold, the currently output multiplex control signal is locked as the locking result, and the process switches from the reference detection phase to the charging operation phase. During the reference detection phase or the charging operation phase, whenever the hardware trigger circuit detects an edge transition on the CP signal line, a gating pulse with a preset time width is output. During the duration of the gating pulse, the switching elements in the impedance branches corresponding to the effective levels in the multiplex control signals are synchronously turned on. At the end of the gating pulse, all switching elements are synchronously restored to the off state.

[0007] By adopting the above technical solution, the main control unit starts from an unloaded state during the reference detection phase and gradually tests different switch combinations to detect the original reflection characteristics of the cable. The main control unit uses the overshoot amplitude value to guide the digitally adjustable impedance array to perform gradient approximation in order to find an impedance path that matches the unknown cable parasitic parameters. After finding the matching combination, the main control unit uses a gating pulse to control the transient action of the switching element, so that the impedance branch is connected to the circuit only during the time window when high-frequency ringing occurs at the signal edge. Since the main control unit disconnects the impedance branch during the steady-state plateau period, it avoids the continuous RC filtering that delays the voltage jump rate. The main control unit achieves instantaneous absorption of ringing energy, solves the problems of signal edge trailing and waveform distortion in long cable communication, ensures the integrity of the charging guidance signal, and thus improves the accuracy and reliability of charging status interaction.

[0008] In conjunction with some embodiments of the first aspect, in some embodiments, the overshoot amplitude value of the current cycle is calculated based on the voltage extreme value, specifically including: obtaining the steady-state level value on the CP signal line, the steady-state level value including the high-voltage steady-state value and the low-voltage steady-state value; if the edge transition of the current cycle becomes a rising edge transition, the difference between the voltage extreme value and the high-voltage steady-state value is used as the overshoot amplitude value; if the edge transition of the current cycle becomes a falling edge transition, the difference between the low-voltage steady-state value and the voltage extreme value is used as the overshoot amplitude value.

[0009] By adopting the above technical solution, the main control unit uses the acquired high and low voltage steady-state values ​​as a dynamic reference. Since DC level drift is inevitable in long cable transmission, relying solely on theoretical level values ​​cannot reflect the true voltage deviation. The main control unit calculates the difference between the acquired voltage extreme values ​​and the corresponding steady-state level values ​​based on the direction of the edge transition. This difference calculation removes the DC bias component of the signal itself, extracting the absolute value of the transient ringing energy caused solely by parasitic inductance and capacitance, i.e., the overshoot amplitude. This solution uses the overshoot amplitude as the basis for impedance adjustment, eliminating the interference of base voltage fluctuations on ringing intensity and providing an objective, quantitative indicator for precise closed-loop control of the impedance array.

[0010] In conjunction with some embodiments of the first aspect, in some embodiments, obtaining the steady-state level value on the CP signal line specifically includes: during the reference detection phase, after a preset waiting time since each edge transition of the reference pulse signal, multi-point sampling of the voltage on the CP signal line is performed within preset sampling windows of the high-level plateau segment and the low-level plateau segment of the reference pulse signal, respectively; the average value of the multi-point sampling results within the high-level plateau segment is taken as the high-level steady-state value, and the average value of the multi-point sampling results within the low-level plateau segment is taken as the low-level steady-state value; the preset waiting time is longer than the attenuation time of the overshoot caused by the edge transition on the CP signal line, so that the sampling window falls into the steady-state range after the overshoot has been attenuated.

[0011] By adopting the above technical solution, the main control unit sets a waiting time longer than the overshoot attenuation time, thus forcing subsequent sampling actions to cross the violent oscillation range caused by edge transitions in timing. After the level enters a smoothing period, the main control unit starts the sampling window and neutralizes high-frequency glitches or random electromagnetic noise that may be mixed in within the steady-state plateau by averaging multiple sampling points. The main control unit extracts a pure steady-state voltage reference by combining time-axis misalignment avoidance with amplitude-axis smoothing filtering. This solution prevents ringing tail fluctuations or environmental interference from being mistaken for steady-state levels, ensuring the data reliability of subsequent extreme value comparisons and overshoot calculations.

[0012] In conjunction with some embodiments of the first aspect, in some embodiments, the target switch combination includes a rising edge target switch combination and a falling edge target switch combination, and the multiplexing control signal correspondingly includes a first multiplexing control signal and a second multiplexing control signal; the overshoot amplitude value includes a rising edge overshoot amplitude value and a falling edge overshoot amplitude value; the updated target switch combination is determined based on the overshoot amplitude value, and the multiplexing control signal corresponding to the updated target switch combination is output to the hardware trigger circuit, specifically including: within the period of each rising edge transition of the reference pulse signal, updating the first multiplexing control signal based on the rising edge overshoot amplitude value until the rising edge overshoot amplitude value is less than or equal to a preset overshoot threshold, and locking the currently output first multiplexing control signal; within the period of each falling edge transition of the reference pulse signal, updating the second multiplexing control signal based on the falling edge overshoot amplitude value until the falling edge overshoot amplitude value is less than or equal to a preset overshoot threshold, and locking the currently output second multiplexing control signal.

[0013] By adopting the above technical solution, the main control unit constructs two independent switching combinations and multiple control signals for the rising and falling edges. In actual charging circuits, the parasitic diodes of semiconductor switching devices and the distributed capacitance of cables exhibit asymmetrical charging and discharging responses under forward and reverse voltages, resulting in differences in the ringing frequency and amplitude generated by the rising and falling edges. The main control unit independently updates and locks the impedance branches based on the overshoot amplitude values ​​in different directions, ensuring that both transition directions have dedicated discharge paths. This solution avoids the underdamping or overdamping phenomenon on one side caused by using a single compromise impedance, achieving refined impedance matching across the entire signal cycle.

[0014] In conjunction with some embodiments of the first aspect, in some embodiments, after entering the charging operation phase, the method further includes: determining the type of edge to be triggered based on the current steady-state level on the CP signal line, and switching the currently output multiplexing control signal in advance before the CP signal line experiences an edge transition corresponding to the type of edge to be triggered; wherein, when the CP signal is in a low steady-state state, the type of edge to be triggered is a rising edge, and the first multiplexing control signal is used as the currently output multiplexing control signal; when the CP signal is in a high steady-state state, the type of edge to be triggered is a falling edge, and the second multiplexing control signal is used as the currently output multiplexing control signal.

[0015] By employing the above technical solution, the main control unit utilizes the alternating high and low level transitions of the PWM square wave to infer the direction of the next edge transition when the signal is in its current steady-state plateau. The main control unit uses this stable time window to preload multiple control signals matching the next edge to the hardware output. When the actual edge transition occurs, the impedance network configuration required by the main control unit is already in a ready state. In summary, this solution eliminates the software execution delay caused by logic judgments and register writes after the transition occurs, improving the transient response speed of impedance matching.

[0016] In conjunction with some embodiments of the first aspect, in some embodiments, the hardware triggering circuit includes an edge detection circuit, a delay circuit, and a logic gate group connected in sequence; outputting a gating pulse with a preset time width specifically includes: the edge detection circuit responding to an edge transition on the CP signal line to output an edge trigger signal; the delay circuit outputting a gating pulse with a preset time width according to the edge trigger signal; one set of input terminals of the logic gate group receiving multiplexed control signals, and another set of input terminals receiving the gating pulse, and outputting the multiplexed control signals to the corresponding switching elements in the digitally adjustable impedance array during the effective level of the gating pulse.

[0017] By adopting the above technical solution, the main control unit directly captures physical level transitions through edge detection circuitry, bypassing the software interrupt response process. The main control unit uses a delay circuit to convert transient transitions into fixed-width gating pulses, and utilizes logic gates as transparent switches, using the time window of the gating pulses to trim preset multi-channel control signals. Through the coordinated action of these hardware logic units, the main control unit establishes a physical impedance path within a microsecond timescale. The main control unit completes bypass discharge the instant ringing energy is present and immediately cuts off the path after the energy dissipates. This solution ensures that the impedance branch conducts only during the ringing window, achieving a balance between high-precision ringing absorption and steady-state low power consumption.

[0018] In conjunction with some embodiments of the first aspect, in some embodiments, after entering the charging operation phase, the method further includes: continuing to collect the voltage extreme values ​​on the CP signal line and calculating the overshoot amplitude value for the corresponding period during the duration of the gating pulse in each cycle; if the overshoot amplitude values ​​corresponding to a preset number of consecutive cycles are all greater than a preset overshoot threshold, then it is determined that the parasitic parameters of the cable connected to the CP signal line have drifted; while maintaining the PWM duty cycle unchanged in the current charging operation phase, based on the currently locked multi-channel control signals as a reference, incrementally updating the multi-channel control signals based on the latest overshoot amplitude value and relocking them, thereby completing the online adaptive calibration of impedance without interrupting charging communication.

[0019] By adopting the above technical solution, the main control unit reuses the window mechanism of the gating pulse during the charging operation phase to maintain background monitoring of the signal overshoot state. Because the parasitic parameters of the charging cable may drift slowly or even suddenly during use due to bending, temperature rise, or material aging, the original matching impedance may become invalid. The main control unit filters out occasional environmental noise interference through multiple consecutive cycles of threshold exceeding judgment. After confirming that the impedance is indeed mismatched, the main control unit actively interrupts communication and returns to the reference detection phase to recalibrate the impedance. This solution enables the charging guidance signal processing equipment to have closed-loop adaptive capability to cope with environmental changes, ensuring the reliability of state interaction during long-cycle charging.

[0020] Secondly, this application provides a charging guidance signal processing device, which includes a main control unit, a hardware trigger circuit, and a digitally adjustable impedance array. The digitally adjustable impedance array includes multiple impedance branches connected in parallel between the CP signal line and the ground terminal. Each impedance branch includes a series-connected impedance element and a switching element. The main control unit includes one or more processors and a memory. The memory is coupled to one or more processors and is used to store computer program code, which includes computer instructions. One or more processors call the computer instructions to cause the main control unit to execute the method described in the first aspect and any possible implementation thereof.

[0021] Thirdly, this application provides a computer-readable storage medium storing computer instructions that, when executed on a main control unit, cause the main control unit to perform the method described in the first aspect and any possible implementation thereof.

[0022] Fourthly, this application provides a computer program product, including a computer program or instructions that, when executed on a main control unit, cause the main control unit to perform the method described in the first aspect and any possible implementation thereof.

[0023] Understandably, the charging guidance signal processing device provided in the second aspect, the computer-readable storage medium provided in the third aspect, and the computer program product provided in the fourth aspect are all used to execute the methods provided in the embodiments of this application. Therefore, the beneficial effects they can achieve can be referred to the beneficial effects in the corresponding methods, and will not be repeated here.

[0024] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0025] 1. Because the main control unit uses the overshoot amplitude value to guide the digital adjustable impedance array to perform gradient approximation, and after finding the matching combination, the gating pulse is used to make the impedance branch only transiently connected to the circuit during the time window when the high-frequency ringing occurs at the signal edge and disconnected during the steady-state plateau period, thus avoiding the continuous RC filtering that delays the voltage jump rate, it realizes the instantaneous and accurate absorption of ringing energy under different cable parasitic parameters. It effectively solves the problem that fixed RC filtering parameters in related technologies are prone to causing signal edge trailing and waveform distortion in long cable communication, thereby ensuring the integrity of the charging guidance signal and improving the accuracy and reliability of high-power charging status interaction.

[0026] 2. Because the main control unit constructs independent target switch combinations and multiple control signals for the rising and falling edges, and updates and locks the impedance branches independently based on the overshoot amplitude value in their respective directions, both forward and reverse transitions can obtain dedicated discharge paths. This effectively solves the problem in related technologies where single impedance matching cannot simultaneously address the ringing suppression of rising and falling edges when facing asymmetrical parasitic parameters of devices and cables, thereby achieving refined impedance matching of the entire cycle signal edges.

[0027] 3. Because the main control unit directly captures physical level transitions through edge detection circuits, generates gating pulses with fixed time widths using delay circuits, and controls switching elements using hardware pass-through mechanisms of logic gates, the software interrupt response process is bypassed. A physical impedance path is established within a microsecond timescale and immediately cut off after energy dissipation. This effectively solves the problem in related technologies where software execution delays cause the impedance branch to fail to intervene synchronously with high-frequency ringing, thus missing the absorption opportunity. In this way, a balance is achieved between high-precision transient ringing absorption and steady-state low-power operation of the system. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a circuit structure of a charging guidance signal processing device in an embodiment of this application;

[0029] Figure 2 This is a flowchart illustrating a charging guidance signal processing method according to an embodiment of this application;

[0030] Figure 3 This is another flowchart illustrating a charging guidance signal processing method in an embodiment of this application;

[0031] Figure 4 This is a schematic diagram of the physical device structure of the main control unit in the embodiments of this application. Detailed Implementation

[0032] The terminology used in the following embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. As used in the specification of this application, the singular expressions “a,” “an,” “the,” “the,” and “this” are intended to include the plural expressions as well, unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this application refers to any or all possible combinations including one or more of the listed items.

[0033] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature, and in the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more.

[0034] This application provides a charging guidance signal processing method, device, product, and medium. The following is in conjunction with... Figure 1 This application describes a charging guidance signal processing device provided in its embodiments. Please refer to [link / reference]. Figure 1 This is a schematic diagram of a circuit structure of a charging guidance signal processing device in an embodiment of this application.

[0035] The charging guidance signal processing device 100 includes a main control unit 101, a high-speed ADC acquisition module 1011, an impedance matching algorithm module 1012, a hardware trigger circuit 102, an edge detection circuit 1021, a delay circuit 1022 and a logic gate group 1023, and a digitally adjustable impedance array 103.

[0036] The CP signal line 110 serves as the transmission channel for the charging pilot signal (Control Pilot). One end connects to the national standard pilot circuit node on the charging pile side, carrying a 1kHz PWM square wave signal to enable status interaction between the charging pile and the on-board charger (OBC) and to transmit the maximum allowable charging current. The other end acts as a sampling terminal, electrically connected to the high-speed ADC acquisition module 1011 of the main control unit 101, and is also connected to the hardware trigger circuit 102 to provide an edge trigger source. The CP signal line 110 is also coupled in parallel with the digitally adjustable impedance array 103 to absorb ringing energy from the impedance matching branch when an edge transition occurs.

[0037] The main control unit 101 is the control core of the charging guidance signal processing device 100, used to perform processes such as sending reference pulse signals, calculating overshoot amplitude values, determining target switch combinations, and outputting multiple control signals. The main control unit 101 includes a high-speed ADC acquisition module 1011 and an impedance matching algorithm module 1012.

[0038] The high-speed ADC acquisition module 1011 is electrically connected to the sampling terminal of the CP signal line 110. It is used to perform high-speed sampling of the transient voltage on the CP signal line 110 within a very short time window after an edge transition, obtaining voltage extreme values ​​(including the voltage peak at the rising edge transition and the voltage valley at the falling edge transition), and to perform multi-point sampling of the CP signal line 110 within the steady-state plateau segment to obtain high-level and low-level steady-state values. The sampling process of the high-speed ADC acquisition module 1011 is jointly controlled by the trigger signal of the hardware trigger circuit 102 and the internal timing of the main control unit 101 to ensure that the sampling time is precisely aligned with the signal edge on the microsecond scale.

[0039] Impedance matching algorithm module 1012 is coupled to high-speed ADC acquisition module 1011. It is used to calculate the overshoot amplitude value of the current cycle based on the acquired voltage extreme value and steady-state level value, and compare the overshoot amplitude value with the preset overshoot threshold value. In the reference detection phase, impedance matching algorithm module 1012 performs impedance configuration gradient approximation based on the overshoot amplitude value in each pulse cycle, dynamically updates and outputs multiple control signals to hardware trigger circuit 102 to gradually adjust the combination of conducting branches in digital adjustable impedance array 103. When the overshoot amplitude value converges to within the preset overshoot threshold value, the corresponding target switch combination is locked and the locked multiple control signals are output, thereby switching from the reference detection phase to the charging operation phase.

[0040] The hardware trigger circuit 102 is located between the CP signal line 110 and the switching control terminal of the digital adjustable impedance array 103. It generates a gating pulse with a preset time width at the instant the edge of the CP signal line 110 changes, thereby transmitting the multiple control signals output by the main control unit 101 to the digital adjustable impedance array 103 within the ringing time window, realizing the transient closing and opening of the impedance branch. Specifically, the hardware trigger circuit 102 includes an edge detection circuit 1021, a delay circuit 1022, and a logic gate group 1023 connected in sequence.

[0041] The input terminal of the edge detection circuit 1021 is connected to the CP signal line 110 and is used to output an edge trigger signal in response to the rising or falling edge transition on the CP signal line 110. At the same time, the edge trigger signal is also fed into the main control unit 101 as an interrupt trigger source, so that the main control unit 101 enters the ADC high-speed sampling process and realizes software and hardware synchronous triggering.

[0042] The delay circuit 1022 is connected to the edge detection circuit 1021 and is used to generate a gating pulse with a preset time width (e.g., 10μs~20μs) based on the edge trigger signal. The preset time width covers the time window required for ringing attenuation, so as to ensure that the impedance matching branch only intervenes in the circuit at the moment of ringing. After the ringing is absorbed, the high input impedance state is restored in time, thereby taking into account both signal integrity and system steady-state low power consumption.

[0043] The logic gate group 1023 has two sets of input terminals. One set of input terminals receives the multiplexing control signals output by the main control unit 101, and the other set of input terminals receives the gating pulse output by the delay circuit 1022. Its output terminal is connected to the switch control pin of each impedance branch in the digitally adjustable impedance array 103. The logic gate group 1023 is used to transmit the multiplexing control signals to the corresponding switching elements during the effective duration of the gating pulse to achieve synchronous conduction of the gating branches; when the gating pulse ends, the logic gate group 1023 cuts off the path of the multiplexing control signals, so that each switching element synchronously returns to the off state.

[0044] A digitally adjustable impedance array 103 is connected in parallel between the CP signal line 110 and the ground terminal GND to provide an adjustable absorption path for high-frequency ringing energy at the moment of edge transition. The digitally adjustable impedance array 103 includes multiple parallel impedance branches. Each impedance branch is composed of impedance elements (Z1, Z2, ..., Zn) connected in series with switching elements (S1, S2, ..., Sn). The resistance values ​​of the impedance elements can be configured differently according to different matching requirements. The switching elements are low-on-resistance semiconductor switching devices, such as metal-oxide-semiconductor field-effect transistors (MOSFETs). Their control terminals are connected to the output terminals of logic gate group 1023 in the hardware trigger circuit 102. By combining and conducting different switching elements, the digitally adjustable impedance array 103 can effectively present multiple impedance values, thereby adapting to the parasitic parameters of charging cables of different lengths and aging levels, achieving dynamic absorption and adaptive impedance matching for CP signal ringing.

[0045] The following describes the process of the method provided in this implementation. Please refer to [link / reference]. Figure 2 This is a flowchart illustrating a charging guidance signal processing method in an embodiment of this application.

[0046] S201. During the reference detection phase, an initial multiplex control signal is output to the hardware trigger circuit, and a reference pulse signal is sent through the CP signal line. The target switch combination indicated by the initial multiplex control signal is empty.

[0047] The reference detection phase refers to the initialization phase in which the main control unit detects the parasitic parameters of the cable connected to the CP signal line and approximates the optimal matching impedance combination before the charging gun is inserted into the charging interface but before power transmission officially begins. The initial multiplexer control signal is the default control signal output by the main control unit at the start of the reference detection phase. This signal consists of multiple logic levels, each corresponding to the on / off command of a switching element on one impedance branch of the digital adjustable impedance array. The target switch combination refers to the set of switching elements that need to be synchronously turned on, indicated by the valid logic bits in the multiplexer control signal. An empty target switch combination indicated by the initial multiplexer control signal means that all logic bits in the multiplexer control signal are invalid in the initial state, i.e., all switching elements on all impedance branches of the digital adjustable impedance array are in the off state. The reference pulse signal refers to the test pulse signal actively output by the main control unit during the reference detection phase to detect the parasitic parameters of the cable. The frequency, amplitude and duty cycle of the reference pulse signal are usually consistent with the CP signal used in the formal charging operation phase. For example, a PWM square wave with a frequency of 1kHz, a high level amplitude of +12V, a low level amplitude of -12V and a duty cycle of 50%.

[0048] In one embodiment of this application, the reference pulse signal may use a duty cycle compatible with the initial stage of the national standard handshake (e.g., the silent phase before 9V DC detection or a 5% non-standard duty cycle) to avoid misjudgment by OBC.

[0049] Specifically, when the charging gun is detected to be inserted and the CP signal line is in an unloaded state without vehicle load, the main control unit enters the reference detection phase. The main control unit first sets the initial multiplexed control signals to a fully inactive level and outputs them to the digitally adjustable impedance array through the logic gates of the hardware trigger circuit. This keeps the switching elements on all impedance branches open, thus causing the CP signal line to exhibit a raw high input impedance state without any matching impedance. Subsequently, the main control unit sends a reference pulse signal to the cable side through the CP signal line. This reference pulse signal, under the influence of the parasitic inductance and capacitance of the long cable, generates raw overshoot and ringing waveforms at its edges, providing raw reference data for subsequent overshoot amplitude acquisition. Using the unloaded switch combination as the detection starting point ensures that the acquired overshoot amplitude value fully reflects the cable's own parasitic characteristics, avoiding interference from the preset impedance in the digitally adjustable impedance array.

[0050] Optionally, in some embodiments, the main control unit may also determine the charging connection confirmation (CC) status by reading the DC level on the CP signal line before entering the reference detection phase. The reference detection phase is only started when the CC signal indicates that the charging gun has been reliably inserted and the vehicle is in the standard 9V state before the handshake, so as to avoid erroneously triggering the reference detection process.

[0051] S202. In response to the edge transition of the reference pulse signal in the current cycle, the voltage extreme value on the CP signal line is collected, and the overshoot amplitude value of the current cycle is calculated based on the voltage extreme value.

[0052] Here, an edge transition refers to a rising edge transition on the CP signal line, where the voltage level changes from low to high, or a falling edge transition, where the voltage level changes from high to low. Voltage extremes refer to the extreme voltage values ​​on the CP signal line caused by transient overshoot due to edge transitions; for rising edge transitions, this is the voltage peak, and for falling edge transitions, it is the voltage valley. Overshoot amplitude refers to the deviation of the voltage extreme value from the corresponding steady-state level on the CP signal line, used to characterize the ringing intensity caused by edge transitions within the current cycle. For example, when the steady-state value of the high voltage is +12V and the voltage peak value sampled at the rising edge is +15V, the corresponding overshoot amplitude is 3V.

[0053] Specifically, during the reference detection phase, whenever the main control unit sends a reference pulse signal through the CP signal line and an edge transition occurs, the high-speed ADC acquisition module of the main control unit responds to the edge transition, is synchronously awakened by the edge trigger signal of the hardware trigger circuit, and enters the high-speed sampling mode. Within a very short time window after the edge transition (e.g., 0μs~20μs), it continuously samples the transient voltage on the CP signal line at a high sampling rate. After sampling is completed, the main control unit selects the maximum or minimum value from the transient voltage sample sequence acquired in this cycle as the voltage extreme value (the maximum value is taken when the current cycle is a rising edge transition, and the minimum value is taken when the current cycle is a falling edge transition). Then, the main control unit performs a difference calculation based on the voltage extreme value and the pre-acquired steady-state level value to obtain the overshoot amplitude value of the current cycle, and transmits the overshoot amplitude value to the impedance matching algorithm module for subsequent threshold determination and switch combination update.

[0054] S203. When the overshoot amplitude value is greater than the preset overshoot threshold, the updated target switch combination is determined according to the overshoot amplitude value, and the multi-channel control signal corresponding to the updated target switch combination is output to the hardware trigger circuit.

[0055] The preset overshoot threshold refers to the voltage threshold used to determine whether the current ringing intensity is within a safe range. This threshold can be set according to the tolerance range of the on-board charger for the CP signal level and the error range of the CP signal level specified in the national standard. For example, it can be set to 5%~10% of the steady-state level amplitude. When the steady-state level is ±12V, the preset overshoot threshold can be set to 0.6V~1.2V. The updated target switch combination refers to the switch combination formed by the main control unit adding a conducting switch branch to the set of already conducting switches based on the overshoot amplitude value of the current cycle.

[0056] Specifically, the impedance matching algorithm module of the main control unit compares the overshoot amplitude value obtained in step S202 with the preset overshoot threshold. When the overshoot amplitude value is greater than the preset overshoot threshold, it indicates that the CP signal line of the current cycle is still in an underdamped state and the ringing is not fully absorbed. At this time, the main control unit determines the number of impedance branches to be added and the resistance value of the impedance branches according to the deviation between the overshoot amplitude value and the preset overshoot threshold (for example, when the overshoot amplitude value is large, more impedance branches are added or impedance branches with smaller resistance values ​​are added; when the overshoot amplitude value is small, only one impedance branch with a larger resistance value is added). These newly added impedance branches are then combined with the currently connected impedance branches to form the updated target switch combination.

[0057] The main control unit then encodes the updated target switch combination into corresponding multiplexed control signals and outputs them to the logic gates of the hardware trigger circuit via control pins. These signals are then applied to the digitally adjustable impedance array when the edge transition arrives in the next cycle. This gradient approximation method allows for gradual convergence to the optimal matching impedance without introducing excessive damping that could lead to edge tailing.

[0058] Optionally, in some embodiments, the main control unit may also pre-establish a lookup table between the overshoot amplitude value and the target switch combination, and directly look up the table to obtain the corresponding target switch combination according to the interval in which the currently collected overshoot amplitude value falls, so as to reduce the number of approximation cycles of impedance configuration and accelerate the convergence speed of the reference detection stage.

[0059] S204. Repeatedly calculate the overshoot amplitude value in each cycle of the reference detection phase. When the overshoot amplitude value is less than or equal to the preset overshoot threshold, lock the current output multi-channel control signal as the locking result, and switch from the reference detection phase to the charging operation phase.

[0060] Locking refers to the main control unit ceasing its update operations on each logic bit in the current multi-channel control signal, and maintaining the multi-channel control signal as a steady-state configuration result for output. The charging operation phase refers to the working stage after the main control unit completes impedance matching detection, where it formally interacts with the on-board charger for charging status and power transmission. During this phase, the main control unit outputs a duty cycle PWM signal corresponding to the allowable charging current through the CP signal line.

[0061] Specifically, during the reference detection phase, the main control unit calculates the overshoot amplitude and updates the multiple control signals for each edge transition cycle of the reference pulse signal according to steps S202 to S203. After each update of the multiple control signals, when the edge transition of the next pulse cycle arrives, a new impedance branch combination in the digital adjustable impedance array will be connected to the CP signal line to absorb the ringing energy generated by the edge transition, so that the overshoot amplitude value collected in this cycle gradually decreases. When the overshoot amplitude value calculated in a certain cycle is less than or equal to the preset overshoot threshold, the main control unit determines that the target switch combination corresponding to the current multiple control signal has achieved the optimal matching of the current cable parasitic parameters, and then stops the gradient approximation process and keeps the current multiple control signal as the lock value for output. After that, the main control unit switches the reference pulse signal to the CP signal with a duty cycle corresponding to the allowable charging current, switches from the reference detection phase to the charging operation phase, and starts the normal charging handshake and PWM duty cycle modulation communication process.

[0062] S205. During the reference detection phase or charging operation phase, whenever the hardware trigger circuit detects an edge transition on the CP signal line, it outputs a strobe pulse with a preset time width.

[0063] This step specifically includes:

[0064] The edge detection circuit responds to the edge transition on the CP signal line and outputs an edge trigger signal.

[0065] The delay circuit outputs a gating pulse with a preset time width based on the edge trigger signal.

[0066] One set of inputs of the logic gate group receives multiplexing control signals, and the other set of inputs receives strobe pulses. During the effective level of the strobe pulse, the multiplexing control signals are output to the corresponding switching elements in the digitally adjustable impedance array.

[0067] The strobe pulse is a control pulse output by the hardware trigger circuit, used to define the time window for releasing multiple control signals to the digitally adjustable impedance array. The preset time width refers to the duration of the strobe pulse. This time width should be greater than or equal to the time required for the ringing energy of the CP signal line to decay completely after an edge transition, and should be much shorter than the duration of a single steady-state plateau segment of the PWM signal, for example, 10μs to 20μs. The edge trigger signal is a transient pulse signal output by the edge detection circuit when an edge transition occurs on the CP signal line, used to indicate the moment of the edge transition to the delay circuit.

[0068] Specifically, this step is carried out throughout each pulse cycle of the reference detection phase and the charging operation phase, without interruption due to phase switching. Within each pulse cycle, the main control unit first monitors the level change on the CP signal line in real time through the edge detection circuit. When a rising edge or falling edge transition occurs on the CP signal line, the edge detection circuit captures the level transition with millivolt-level sensitivity and outputs an edge trigger signal in the form of a narrow pulse.

[0069] The main control unit then receives the edge-triggered signal through a delay circuit and shapes it into a gating pulse with a preset time width based on its internal monostable circuit or RC timing network. Finally, the main control unit feeds the multiple control signals output from the main control terminal into one set of input terminals of the logic gate group and feeds the gating pulse output from the delay circuit into another set of input terminals of the logic gate group. During the effective level of the gating pulse, the logic gate group performs bit-by-bit release of the multiple control signals and outputs the multiple control signals to the corresponding switching element control terminals in the digital adjustable impedance array.

[0070] This hardware triggering mechanism ensures that the gating window and the ringing time are precisely aligned on the order of microseconds, avoiding missed ringing absorption opportunities due to software response delays in the main control unit.

[0071] S206. During the duration of the strobe pulse, the switching elements in the impedance branches corresponding to the effective level of the multiple control signals are synchronously turned on, so as to connect the corresponding impedance branches between the CP signal line and the ground terminal and absorb the reflected signal generated by the edge transition.

[0072] Among them, the effective level refers to the logic level state in the multiplexed control signal used to indicate the conduction of the corresponding switching element. For example, a high level can be set as the effective level and a low level as the ineffective level. The reflected signal refers to the parasitic reflected waveform generated at the moment of edge transition of the CP signal due to the mismatch between the characteristic impedance of the cable and the impedance of the terminal load. It propagates back and forth along the cable and is superimposed on the original signal. In the time domain, it is manifested as a high-frequency ringing superimposed on the edge.

[0073] Specifically, this step occurs after the hardware trigger circuit outputs a strobe pulse and transmits the multiplexed control signals to the digitally adjustable impedance array. The main control unit uses logic gates to simultaneously apply each valid logic bit in the multiplexed control signals to the control terminal of the corresponding switching element (e.g., the gate of a MOSFET). Under the action of the gate control voltage, each switching element quickly switches from the off state to the on state, thereby connecting the impedance element in its impedance branch to the CP signal line and the ground terminal via the switching element, forming a low-impedance absorption path from the CP signal line to the ground terminal.

[0074] The reflected signal energy generated on the CP signal line at the moment of edge transition is discharged to the ground terminal through the absorption path. The corresponding impedance element dampens the high-frequency component of the reflected signal, thereby suppressing overshoot and ringing at the edge of the CP signal.

[0075] Since the combined impedance formed by the parallel connection of multiple impedance branches matches the characteristic impedance of the cable, this absorption process achieves efficient suppression of reflected signals without significantly weakening the edge steepness of the original PWM signal.

[0076] S207. At the end of the strobe pulse, all switching elements are synchronously restored to the off state so that the CP signal line is restored to the high input impedance state.

[0077] The high input impedance state refers to the state where, after all impedance branches in the digitally adjustable impedance array are disconnected from the CP signal line, the CP signal line only exhibits its own parasitic impedance and the input impedance of the downstream sampling circuit. In this state, the equivalent impedance of the CP signal line to ground is much greater than the matching impedance during the absorption period.

[0078] Specifically, after the duration of the gating pulse output by the hardware trigger circuit reaches the preset time width, the gating pulse transitions from an effective level to an ineffective level. The main control unit cuts off the transmission path of multiple control signals to the digital adjustable impedance array through logic gates, causing the control terminals of all switching elements in the digital adjustable impedance array to simultaneously lose their effective drive level. Each switching element then synchronously returns from the on state to the off state, and the connection between all impedance branches in the digital adjustable impedance array and the CP signal line is completely disconnected. At this time, the CP signal line returns to a high input impedance state, no longer forming a continuous ground discharge path for the steady-state plateau segment of the CP signal, thus avoiding continuous power consumption during the steady-state period. Through this dynamic switching mechanism of "instantaneous edge access and disconnection during steady state," the main control unit can effectively absorb the reflected signal within the ringing time window, and ensure the stability of the CP signal line level and the low-power operation of the entire charging guidance signal processing device during the steady state, achieving a balance between high precision and low power consumption.

[0079] Optionally, in some embodiments, the main control unit may also apply a brief reverse bias voltage to the gate of the switching element at the end of the strobe pulse to accelerate the turn-off speed of the MOSFET channel and avoid additional leakage losses caused by the turn-off delay due to gate parasitic capacitance during the steady state.

[0080] In this embodiment, the main control unit continuously updates the target switch combination based on the overshoot amplitude value during the reference detection phase until the overshoot amplitude value is less than or equal to the preset overshoot threshold to lock the multi-channel control signal. Whenever the hardware trigger circuit detects an edge transition on the CP signal line, it outputs a gating pulse with a preset time width. During the duration of the gating pulse, the switching elements in the impedance branch corresponding to the effective level are synchronously turned on and turned off at the end. Therefore, it can adaptively find the optimal matching impedance for unknown and dynamically changing parasitic parameters of the charging cable, and only connect the impedance for absorption during the transient window that generates high-frequency ringing, and restore disconnection during the steady state. This effectively solves the problem in related technologies where the use of a fixed RC filter circuit results in a large filter parameter running through the entire communication cycle, thereby delaying the square wave edge transition rate and causing signal edge trailing and waveform distortion. Thus, it achieves the goal of maintaining signal integrity while suppressing high-frequency ringing at the edge of the CP signal, improving the accuracy and reliability of charging status interaction.

[0081] The above embodiments introduce a charging guidance signal processing scheme that finds the matching impedance through a reference detection stage and uses hardware-triggered gating pulses to realize the transient connection and disconnection of the impedance branch. This initially solves the problems of edge trailing and waveform distortion caused by fixed RC filtering.

[0082] In practical applications, high-power long charging cables often exhibit DC level drift and asymmetric parasitic characteristics under forward and reverse voltages. Furthermore, during long-term charging, cable aging, temperature rise, or bending can easily cause dynamic changes in parasitic parameters.

[0083] Based on the above embodiments, the method provided in this embodiment will be described in further detail below. Please refer to... Figure 3 This is another flowchart illustrating a charging guidance signal processing method in an embodiment of this application.

[0084] S301. During the reference detection phase, an initial multiplex control signal is output to the hardware trigger circuit, and a reference pulse signal is sent through the CP signal line. The target switch combination indicated by the initial multiplex control signal is empty.

[0085] Step S301 is similar to step S201 in the above embodiments, and will not be repeated here.

[0086] S302. In response to the edge transition of the reference pulse signal in the current cycle, the voltage extreme value on the CP signal line is acquired, and the steady-state level value on the CP signal line is obtained. The steady-state level value includes the high voltage steady-state value and the low voltage steady-state value.

[0087] This step specifically includes:

[0088] During the reference detection phase, after a preset waiting time since each edge transition of the reference pulse signal, the voltage on the CP signal line is sampled at multiple points within the preset sampling windows of the high-level plateau segment and the low-level plateau segment of the reference pulse signal.

[0089] The average value of the multi-point sampling results within the high-level plateau segment is taken as the high-level steady-state value, and the average value of the multi-point sampling results within the low-level plateau segment is taken as the low-level steady-state value.

[0090] The preset waiting time is longer than the decay time of the overshoot caused by the edge transition on the CP signal line, so that the sampling window falls into the steady-state range after the overshoot decay is complete.

[0091] The steady-state voltage level refers to the voltage value on the CP signal line after the transient overshoot and ringing attenuation following the edge transition, and after entering the stable plateau segment. The high-level steady-state voltage value refers to the steady-state voltage value on the CP signal line when the reference pulse signal is in the high-level plateau segment; for example, its typical value in the national standard CP signal system is approximately +12V. The low-level steady-state voltage value refers to the steady-state voltage value on the CP signal line when the reference pulse signal is in the low-level plateau segment; for example, its typical value is approximately -12V. The high-level plateau segment refers to the time period within one PWM cycle where the reference pulse signal is at a high level and the voltage waveform has tended to stabilize; the low-level plateau segment refers to the time period within one PWM cycle where the reference pulse signal is at a low level and the voltage waveform has tended to stabilize.

[0092] The preset waiting time refers to the length of time the main control unit waits from the moment of edge transition to the start of steady-state sampling. This time is set based on the time required for the high-frequency ringing caused by the edge transition to completely attenuate on the CP signal line. It is typically set to 30μs~100μs to ensure the sampling window completely avoids the ringing region. The preset sampling window refers to the time window during which the main control unit performs multi-point sampling of the voltage on the CP signal line within the steady-state plateau segment. Its width must be less than the remaining duration of the steady-state plateau segment; a typical value is 100μs~300μs, and the number of sampling points can be 8~32.

[0093] Specifically, this step occurs each time the reference pulse signal undergoes an edge transition during the reference detection phase. On one hand, the high-speed ADC acquisition module of the main control unit samples the transient overshoot waveform on the CP signal line at high speed and obtains the voltage extreme value within a very short time window after the edge transition. This process is the same as the voltage extreme value acquisition process described in step S202. On the other hand, the main control unit starts timing from the edge transition moment within the same cycle. After a preset waiting time, it samples the voltage on the CP signal line at multiple points within the preset sampling windows corresponding to the high-level plateau segment and the low-level plateau segment of the reference pulse signal, respectively.

[0094] It should be noted that the preset acquisition window of the ADC and the duration of the gating pulse can coincide or be independent of each other.

[0095] The arithmetic mean of multiple sampling results within the high-level plateau segment is used to obtain the high-level steady-state value, and the arithmetic mean of multiple sampling results within the low-level plateau segment is used to obtain the low-level steady-state value. Using multi-point sampling and averaging filters out the influence of random noise and power frequency interference on the steady-state level acquisition, thereby improving the accuracy of the steady-state level value. Since the preset waiting time is longer than the attenuation time of the overshoot caused by edge transitions on the CP signal line, the sampling window must fall within the steady-state range after the overshoot has attenuated, avoiding the erroneous inclusion of ringing tail fluctuations in the steady-state level calculation.

[0096] The main control unit completes the acquisition and calculation of the high-level steady-state value and the low-level steady-state value within the initial few pulse cycles of the reference detection phase, and uses the steady-state level value as a fixed reference value in the subsequent reference detection phase and charging operation phase; or, the main control unit performs multi-point sampling of the high-level plateau segment and the low-level plateau segment in each pulse cycle to dynamically update the steady-state level value, so that the steady-state level value can adaptively track the level drift on the CP signal line.

[0097] Optionally, in some embodiments, the main control unit may first remove outlier sampling points that exceed the preset deviation range from the multi-point sampling results, and then average the remaining sampling points to avoid occasional pulse interference affecting the accuracy of the steady-state level value; or the main control unit may use a moving average filtering method to smooth the steady-state level value over multiple consecutive periods to further improve the stability of the steady-state level value.

[0098] S303. If the current cycle edge transition becomes a rising edge transition, then the difference between the voltage extreme value and the high voltage steady-state value is taken as the overshoot amplitude value.

[0099] Among them, rising edge transition refers to the voltage level change process of the CP signal line from a low steady-state value to a high steady-state value. During this process, the CP signal line will generate a transient overshoot exceeding the high steady-state value due to the effect of cable parasitic parameters. The highest point of the overshoot waveform is the voltage extreme value collected in the current cycle.

[0100] Specifically, this step is executed when the main control unit determines that the edge transition type of the current cycle is a rising edge transition. The main control unit first determines the edge transition type of the current cycle based on the polarity of the edge trigger signal provided by the hardware trigger circuit (or by comparing the direction of level change on the CP signal line before and after the edge transition). When it is determined to be a rising edge transition, the main control unit calls the voltage extreme value (corresponding to the voltage peak value) acquired in step S302 within that cycle, and retrieves the saved high-voltage stable-state value. The high-voltage stable-state value is subtracted from the voltage extreme value using a subtraction operation, and the resulting difference is the rising edge overshoot amplitude value of the current cycle, used to reflect the upward overshoot intensity caused by the rising edge transition. For example, when the high-voltage stable-state value is +12V and the voltage peak value acquired in this cycle is +15V, the calculated rising edge overshoot amplitude value is 3V. The main control unit transmits this rising edge overshoot amplitude value to the impedance matching algorithm module for updating the first multiplex control signal in subsequent step S305.

[0101] S304. If the current cycle edge transition becomes a falling edge transition, then the difference between the low voltage steady-state value and the voltage extreme value is taken as the overshoot amplitude value.

[0102] Among them, the falling edge transition refers to the voltage level change process of the CP signal line from the high voltage steady state value to the low voltage steady state value. During this process, the CP signal line will generate a transient undershoot lower than the low voltage steady state value due to the effect of cable parasitic parameters. The lowest point of the undershoot waveform is the voltage extreme value collected in the current cycle.

[0103] Specifically, this step is executed when the main control unit determines that the edge transition type of the current cycle is a falling edge transition. The main control unit determines the edge transition type of the current cycle based on the polarity of the edge trigger signal provided by the hardware trigger circuit. When it is determined to be a falling edge transition, the main control unit calls the voltage extreme value (corresponding to the voltage valley value) collected in step S302 within this cycle, and retrieves the saved low-voltage steady-state value. The low-voltage steady-state value is subtracted from the voltage extreme value through a subtraction operation, and the difference is the falling edge overshoot amplitude value of the current cycle, which is used to reflect the downward overshoot intensity caused by the falling edge transition. For example, when the low-voltage steady-state value is -12V and the voltage valley value collected in this cycle is -15V, the calculated falling edge overshoot amplitude value is 3V.

[0104] The target switch combination includes a rising edge target switch combination and a falling edge target switch combination, and the corresponding multiplex control signals include a first multiplex control signal and a second multiplex control signal. The overshoot amplitude values ​​include rising edge overshoot amplitude values ​​and falling edge overshoot amplitude values.

[0105] S305. During the period of each rising edge transition of the reference pulse signal, when the rising edge overshoot amplitude value is greater than the preset overshoot threshold, the first multiplexing control signal is updated based on the rising edge overshoot amplitude value until the rising edge overshoot amplitude value is less than or equal to the preset overshoot threshold, and the currently output first multiplexing control signal is locked.

[0106] The first multi-channel control signal refers to the multi-channel control signal output by the main control unit specifically for absorbing and matching the overshoot ringing caused by the rising edge transition. The target switch combination indicated by this signal is the rising edge target switch combination. The rising edge target switch combination refers to the set of impedance branches that should be synchronously turned on to absorb the rising edge reflected signal when the rising edge transition occurs. The rising edge overshoot amplitude value is the amplitude value reflecting the rising edge overshoot intensity calculated in step S303.

[0107] Specifically, this step occurs within the period of each rising edge transition of the reference pulse signal during the reference detection phase. The impedance matching algorithm module of the main control unit compares the rising edge overshoot amplitude value calculated for the current period with the preset overshoot threshold.

[0108] When the rising edge overshoot amplitude is greater than the preset overshoot threshold, the main control unit determines that the matching impedance in the current rising edge direction has failed to fully absorb the reflected signal. Then, based on the magnitude of the rising edge overshoot amplitude, it adds a new impedance branch to the already conducted impedance branch or switches to an impedance branch with a lower resistance value, forming an updated rising edge target switch combination. This is then encoded into an updated first multiplex control signal and output to the logic gate group of the hardware trigger circuit, so that it can act on the digitally adjustable impedance array when the next rising edge transition arrives.

[0109] During the subsequent rising edge transition period, the main control unit re-acquires the voltage peak value and calculates the new rising edge overshoot amplitude value. If it is still greater than the preset overshoot threshold, the first multiplex control signal is updated according to the above gradient approximation logic.

[0110] When the overshoot amplitude value calculated by a certain rising edge transition cycle is less than or equal to the preset overshoot threshold, the main control unit determines that the matching impedance in the rising edge direction has reached the optimal value, and then stops updating the first multiplexing control signal and locks the current first multiplexing control signal.

[0111] S306. During the period of each falling edge transition of the reference pulse signal, when the falling edge overshoot amplitude value is greater than the preset overshoot threshold, the second multiplexing control signal is updated based on the falling edge overshoot amplitude value until the falling edge overshoot amplitude value is less than or equal to the preset overshoot threshold, and the currently output second multiplexing control signal is locked.

[0112] The second multi-channel control signal refers to the multi-channel control signal output by the main control unit specifically for absorbing and matching the undershoot ringing caused by the falling edge transition. The target switch combination indicated by this signal is the falling edge target switch combination. The falling edge target switch combination refers to the set of impedance branches that should be synchronously turned on to absorb the falling edge reflected signal when the falling edge transition occurs. The falling edge overshoot amplitude value is the amplitude value reflecting the falling edge overshoot intensity calculated in step S304.

[0113] This step occurs within the period of each falling edge transition of the reference pulse signal during the reference detection phase. Its execution logic is similar to that of step S305, except that the object to be updated and locked is changed to the second multiplex control signal, and the reference overshoot amplitude is changed to the falling edge overshoot amplitude value.

[0114] Specifically, the impedance matching algorithm module of the main control unit compares the falling edge overshoot amplitude value calculated in the current cycle with the preset overshoot threshold. When the falling edge overshoot amplitude value is greater than the preset overshoot threshold, the main control unit adds a new impedance branch to the already conducted impedance branch or switches to an impedance branch with a lower resistance value to form an updated falling edge target switch combination, and encodes it into an updated second multiplex control signal to be output to the logic gate group of the hardware trigger circuit.

[0115] The gradient approximation logic continues to update the signal during subsequent falling edge transition cycles until the falling edge overshoot amplitude value calculated in a certain falling edge transition cycle is less than or equal to the preset overshoot threshold. At this point, the main control unit locks and holds the current second multiplex control signal.

[0116] Optionally, in some embodiments, considering that the mechanism of the effect of cable parasitic parameters on the reflected signal is not completely symmetrical in the rising edge direction and the falling edge direction (for example, the equivalent impedance of the MOSFET parasitic body diode and the cable distributed capacitance differs under positive and negative voltages), the main control unit can also maintain independent rising edge target switch combinations and falling edge target switch combinations for the first multiplex control signal and the second multiplex control signal respectively, so that the matching impedance in the rising edge and falling edge directions can be independently optimized and do not interfere with each other, thereby obtaining the best ringing absorption effect in both the rising edge and falling edge directions.

[0117] Optionally, in some embodiments, in order to match the multiplexed control signals transmitted by the hardware triggering circuit with the type of edge to be triggered at each edge transition, the main control unit determines the type of edge to be triggered based on the current steady-state level on the CP signal line during both the reference detection phase and the charging operation phase, and switches the currently output multiplexed control signals in advance before the CP signal line experiences an edge transition corresponding to the type of edge to be triggered.

[0118] When the CP signal is in a low-voltage stable state, the type of the edge to be triggered is a rising edge, and the main control unit uses the first multiplex control signal as the current output multiplex control signal.

[0119] When the CP signal is in a high-voltage stable state, the trigger edge type is a falling edge, and the main control unit uses the second multiplexing control signal as the current output multiplexing control signal.

[0120] S307. After locking the currently output first multiplex control signal and second multiplex control signal, switch from the reference detection stage to the charging operation stage.

[0121] Specifically, when the main control unit has completed the locking of the first and second multi-channel control signals respectively, that is, when the rising edge target switch combination and the falling edge target switch combination in the digital adjustable impedance array have converged to the optimal matching impedance combination in their respective directions, the main control unit determines that the impedance matching detection task of the reference detection stage has been completed, and then ends the transmission of the reference pulse signal, and switches the PWM signal on the CP signal line to a duty cycle signal corresponding to the actual allowable charging current (for example, according to the rated output current of the charging pile, the corresponding duty cycle PWM wave is generated according to the conversion relationship between the duty cycle and the maximum charging current specified in the national standard), thereby entering the charging operation stage and initiating the formal charging handshake and power transmission process with the vehicle's on-board charger.

[0122] During the charging operation phase, the main control unit continuously determines the type of edge to be triggered based on the current steady-state level on the CP signal line and switches the current output multi-channel control signal in advance. At the same time, the hardware triggering circuit continues to transmit the corresponding multi-channel control signal to the digital adjustable impedance array at each edge transition moment according to the process of steps S308 to S310, so as to realize the dynamic absorption of CP signal edge ringing.

[0123] Optionally, in some embodiments, the main control unit may also continue to collect the voltage extreme value on the CP signal line and calculate the overshoot amplitude value of the corresponding cycle during the duration of the gating pulse in each cycle after entering the charging operation phase.

[0124] If the overshoot amplitude value corresponding to a preset number of consecutive cycles (e.g., 5-10 consecutive cycles) is greater than the preset overshoot threshold, the main control unit determines that the parasitic parameters of the cable connected to the CP signal line have drifted (e.g., changes in distributed capacitance due to cable bending, temperature rise, or aging). At this time, while maintaining the PWM duty cycle unchanged in the current charging operation stage, the main control unit incrementally updates and relocks the multi-channel control signals based on the latest overshoot amplitude value, using the currently locked multi-channel control signals as a reference, thereby completing online adaptive impedance calibration without interrupting charging communication. Considering that the PWM duty cycle of the CP signal carries the maximum allowable current command in the State C charging state, and according to GB / T18487.1, the duty cycle cannot be arbitrarily interrupted or changed, otherwise the on-board charger will determine that the CP is abnormal and urgently cut off the high-voltage contactor. Therefore, in this embodiment, the main control unit adopts an online incremental calibration method for impedance updating, specifically including:

[0125] (1) Keep the PWM duty cycle, frequency and amplitude unchanged during the current charging operation phase, and continue to carry out normal charging handshake and power transmission;

[0126] (2) Using the rising / falling edge of the running PWM itself as the detection excitation, the voltage extreme value and overshoot amplitude value are obtained in the acquisition window after each edge;

[0127] (3) Based on the currently locked first / second multi-channel control signal, adjust the first / second multi-channel control signal incrementally according to the deviation direction of the overshoot amplitude value relative to the preset overshoot threshold (for example, add or remove a branch on the basis of the current conducting branch, or switch the branch of the adjacent resistance value range), and use the adjustment result as the new locking value.

[0128] (4) Repeat the above process until the overshoot amplitude value of a preset number of consecutive cycles returns to within the preset overshoot threshold.

[0129] Through the aforementioned online incremental calibration mechanism, the main control unit achieves closed-loop adaptive tracking of cable parasitic parameter drift without interrupting CP communication or changing duty cycle semantics, thus balancing the engineering requirements of maintaining signal integrity and uninterrupted charging process.

[0130] S308. During the reference detection phase or charging operation phase, whenever the hardware trigger circuit detects an edge transition on the CP signal line, it outputs a strobe pulse with a preset time width.

[0131] S309. During the duration of the strobe pulse, the switching elements in the impedance branches corresponding to the effective level of the multiple control signals are synchronously turned on, so as to connect the corresponding impedance branches between the CP signal line and the ground terminal and absorb the reflected signal generated by the edge transition.

[0132] S310. At the end of the strobe pulse, all switching elements are synchronously restored to the off state so that the CP signal line is restored to the high input impedance state.

[0133] Steps S308 to S310 are similar to those described in steps S205 to S207 in the above embodiments, and will not be repeated here.

[0134] In this embodiment, the main control unit calculates the rising edge overshoot amplitude and falling edge overshoot amplitude based on the high and low steady-state values, respectively, and independently updates and locks the first and second multi-channel control signals. During the charging operation phase, the multi-channel control signals are switched in advance according to the steady-state level. The transient pass-through selection pulse is transmitted through the hardware trigger circuit composed of edge detection circuit, delay circuit and logic gate group. When the overshoot amplitude value is continuously monitored to be greater than the preset overshoot threshold, the reference detection phase is re-entered. Therefore, DC level bias interference is eliminated, independent and fine matching of forward and reverse asymmetric parasitic parameters is achieved, software execution delay is eliminated to ensure impedance microsecond-level accurate synchronous access, and closed-loop adaptive capability is provided for parameter drift caused by environment and aging. This effectively solves the problem of incomplete edge ringing absorption or communication errors caused by parasitic parameter asymmetry, software response lag and dynamic changes in cable aging in complex high-power charging scenarios. Thus, high-precision anti-interference transmission of CP signal and low-power stable operation of system are achieved throughout the entire life cycle.

[0135] The main control unit of the charging guidance signal processing device in the embodiments of this invention is described below from the perspective of hardware processing. Please refer to [link / reference needed]. Figure 4 This is a schematic diagram of the physical device structure of the main control unit in the embodiments of this application.

[0136] It should be noted that, Figure 4 The structure of the main control unit shown is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of the present invention.

[0137] like Figure 4 As shown, the main control unit includes a CPU 401, which can perform various appropriate actions and processes based on a program stored in the read-only memory ROM 402 or a program loaded from the storage section 408 into the random access memory RAM 403, such as executing the methods described in the above embodiments. The RAM 403 also stores various programs and data required for system operation. The CPU 401, ROM 402, and RAM 403 are interconnected via a bus 404. An I / O interface 405 is also connected to the bus 404.

[0138] The following components are connected to I / O interface 405: input section 406 including audio input devices, push-button switches, etc.; output section 407 including a liquid crystal display (LCD) and audio output devices, indicator lights, etc.; storage section 408 including a hard disk, etc.; and communication section 409 including a network interface card such as a LAN (Local Area Network) card, modem, etc. Communication section 409 performs communication processing via a network such as the Internet. Drive 410 is also connected to I / O interface 405 as needed. Removable media 411, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., are installed on drive 410 as needed so that computer programs read from them can be installed into storage section 408 as needed.

[0139] In particular, according to embodiments of the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program / instructions carried on a computer-readable medium, the computer program / instructions containing computer program / instructions for performing the methods shown in the flowcharts. In such embodiments, the computer program / instructions can be downloaded and installed from a network via communication section 409, and / or installed from removable medium 411. When the computer program is executed by CPU 401, it performs the various functions defined in the present invention.

[0140] It should be noted that specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, optical fiber, portable compact disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this invention, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0141] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. Each block in a flowchart or block diagram may represent a module, program segment, or portion of code, which contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those shown in the drawings.

[0142] Specifically, the main control unit in this embodiment includes a processor and a memory. The memory stores a computer program. When the computer program is executed by the processor, it implements a charging guidance signal processing method provided in the above embodiment.

[0143] In another aspect, the present invention also provides a computer-readable storage medium, which may be included in the main control unit described in the above embodiments; or it may exist independently and not assembled into the main control unit. The storage medium carries one or more computer programs, which, when executed by a processor of the main control unit, cause the main control unit to implement a charging guidance signal processing method provided in the above embodiments.

[0144] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. 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 scope of the technical solutions of the embodiments of this application.

[0145] As used in the above embodiments, depending on the context, the term "when..." can be interpreted as meaning "if...", "after...", "in response to determining...", or "in response to detecting...". Similarly, depending on the context, the phrase "when determining..." or "if (the stated condition or event) is interpreted as meaning "if determining...", "in response to determining...", "when (the stated condition or event) is detected", or "in response to detecting (the stated condition or event)".

[0146] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This program can be stored in a computer-readable storage medium, and when executed, it can include the processes described in the above method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM or random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A charging guidance signal processing method, applied to the main control unit of a charging guidance signal processing device, characterized in that, The charging guidance signal processing device further includes a hardware trigger circuit and a digitally adjustable impedance array. The digitally adjustable impedance array includes multiple impedance branches connected in parallel between the CP signal line and the ground terminal. Each impedance branch includes a series-connected impedance element and a switching element. The method includes: During the reference detection phase, an initial multiplex control signal is output to the hardware trigger circuit, and a reference pulse signal is sent through the CP signal line. The target switch combination indicated by the initial multiplex control signal is empty. In response to the edge transition of the reference pulse signal in the current cycle, the voltage extreme value on the CP signal line is acquired, and the overshoot amplitude value of the current cycle is calculated based on the voltage extreme value. When the overshoot amplitude value is greater than the preset overshoot threshold, the updated target switch combination is determined according to the overshoot amplitude value, and a multi-channel control signal corresponding to the updated target switch combination is output to the hardware trigger circuit. The updated multi-channel control signal acts on the digital adjustable impedance array during the next edge transition. The calculation of the overshoot amplitude value is repeated in each cycle of the reference detection phase. When the overshoot amplitude value is less than or equal to the preset overshoot threshold, the currently output multi-channel control signal is locked as the locking result, and the process switches from the reference detection phase to the charging operation phase. During the reference detection phase or the charging operation phase, whenever the hardware trigger circuit detects an edge transition on the CP signal line, it outputs a strobe pulse with a preset time width. During the duration of the strobe pulse, the switching elements in the impedance branch corresponding to the effective level of the multiplex control signal are synchronously turned on; At the end of the strobe pulse, each of the switching elements is synchronously restored to the off state.

2. The method according to claim 1, characterized in that, The calculation of the overshoot amplitude value for the current cycle based on the voltage extreme value specifically includes: Obtain the steady-state level value on the CP signal line, the steady-state level value includes a high-level steady-state value and a low-level steady-state value; If the edge transition of the current cycle becomes a rising edge transition, then the difference between the voltage extreme value and the high voltage steady-state value is taken as the overshoot amplitude value. If the edge transition of the current cycle becomes a falling edge transition, then the difference between the low voltage steady-state value and the voltage extreme value is taken as the overshoot amplitude value.

3. The method according to claim 2, characterized in that, The process of obtaining the steady-state level value on the CP signal line specifically includes: During the reference detection phase, after a preset waiting time since each edge transition of the reference pulse signal, the voltage on the CP signal line is sampled at multiple points within the preset sampling windows of the high-level plateau segment and the low-level plateau segment of the reference pulse signal, respectively. The average value of the multi-point sampling results within the high-level plateau segment is taken as the high-level steady-state value, and the average value of the multi-point sampling results within the low-level plateau segment is taken as the low-level steady-state value. The preset waiting time is greater than the attenuation time of the overshoot caused by the edge transition on the CP signal line, so that the sampling window falls into the steady-state range after the overshoot attenuation is complete.

4. The method according to claim 3, characterized in that, The target switch combination includes a rising edge target switch combination and a falling edge target switch combination; the multiplex control signal includes a first multiplex control signal and a second multiplex control signal; the overshoot amplitude value includes a rising edge overshoot amplitude value and a falling edge overshoot amplitude value. The step of determining the updated target switch combination based on the overshoot amplitude value and outputting a multi-channel control signal corresponding to the updated target switch combination to the hardware trigger circuit specifically includes: During the period of each rising edge transition of the reference pulse signal, the first multiplexing control signal is updated based on the rising edge overshoot amplitude value until the rising edge overshoot amplitude value is less than or equal to a preset overshoot threshold, and the currently output first multiplexing control signal is locked. During each falling edge transition of the reference pulse signal, the second multiplexing control signal is updated based on the falling edge overshoot amplitude value until the falling edge overshoot amplitude value is less than or equal to a preset overshoot threshold, at which point the currently output second multiplexing control signal is locked.

5. The method according to claim 4, characterized in that, After entering the charging operation phase, the method further includes: The type of edge to be triggered is determined based on the current steady-state level on the CP signal line, and the current output multi-channel control signal is switched in advance before the edge transition corresponding to the type of edge to be triggered occurs on the CP signal line. Specifically, when the CP signal is in a low-voltage stable state, the edge to be triggered is a rising edge, and the first multiplexing control signal is used as the current output multiplexing control signal; when the CP signal is in a high-voltage stable state, the edge to be triggered is a falling edge, and the second multiplexing control signal is used as the current output multiplexing control signal.

6. The method according to claim 1, characterized in that, The hardware triggering circuit includes an edge detection circuit, a delay circuit, and a logic gate group connected in sequence. The output has a gating pulse with a preset time width, specifically including: The edge detection circuit responds to the edge transition on the CP signal line and outputs an edge trigger signal. The delay circuit outputs a gating pulse with the preset time width based on the edge trigger signal; One set of input terminals of the logic gate group receives the multiplexing control signal, and the other set of input terminals receives the gating pulse. During the effective level of the gating pulse, the multiplexing control signal is output to the corresponding switching element in the digitally adjustable impedance array.

7. The method according to claim 1, characterized in that, After entering the charging operation phase, the method further includes: During the duration of the gating pulse in each cycle, the voltage extreme values ​​on the CP signal line are continuously acquired and the overshoot amplitude value of the corresponding cycle is calculated. If the overshoot amplitude value corresponding to a preset number of consecutive cycles is greater than the preset overshoot threshold, it is determined that the parasitic parameters of the cable connected to the CP signal line have drifted. While maintaining the PWM duty cycle unchanged during the current charging operation phase, the multi-channel control signals are incrementally updated and re-locked based on the latest overshoot amplitude value, using the currently locked multi-channel control signals as a reference. This allows for online adaptive impedance calibration without interrupting charging communication.

8. A charging guidance signal processing device, characterized in that, The charging guidance signal processing device includes a main control unit, a hardware trigger circuit, and a digital adjustable impedance array. The digital adjustable impedance array includes multiple impedance branches connected in parallel between the CP signal line and the ground terminal. Each impedance branch includes an impedance element and a switching element connected in series. The main control unit includes: one or more processors and a memory; the memory is coupled to the one or more processors, the memory is used to store computer program code, the computer program code including computer instructions, and the one or more processors call the computer instructions to cause the main control unit to perform the method as described in any one of claims 1-7.

9. A computer-readable storage medium storing computer instructions, characterized in that, When the computer instructions are executed on the main control unit, the main control unit performs the method as described in any one of claims 1-7.

10. A computer program product, comprising a computer program or instructions, characterized in that, When the computer program or instructions are run on the main control unit, the main control unit performs the method as described in any one of claims 1-7.

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