Modulation signal authentication unlocking device for private charging pile

Abstract

The utility model discloses a modulation signal authentication unlocking device for a private charging pile, and belongs to the technical field of electric automobile charging control, embedded system communication and information safety. The system comprises the following components: a vehicle end modulation signal sending module, a charging wire transmission channel, a pile end signal preprocessing module, a signal sampling and processing module, an authentication judgment and control module and a control execution unit. According to the utility model, the modulation signal is generated at the electric vehicle end and is transmitted to the pile end through the charging wire for demodulation and identification, so that the autonomous identity authentication of the vehicle can be effectively realized, the automation, safety and adaptability of the charging process are obviously improved, and the construction and maintenance cost of the system is effectively reduced at the same time.

Description

TECHNICAL FIELD

[0001] The utility model belongs to electric automobile charging control, embedded system communication and information security technical field, concretely relates to a modulation signal authentication unlocking device for private charging pile. BACKGROUND

[0002] With the wide popularity of electric vehicles, the number of private and public charging piles is growing rapidly, which has brought higher requirements for the use permission, security and identification mechanism of charging piles. In order to prevent illegal access, electricity theft and misuse, the existing technology widely uses the following charging pile identity recognition and unlocking control means: (1) user authentication method based on IC card or NFC identification: users need to pass the card or near field communication to transfer identity information to the charging pile, such as IC card authentication method widely used by China State Grid and other large operators to complete user binding and charging authorization control; (2) APP or cloud platform authentication control method: using smart phone application program to scan code or remote control, connecting users and piles, authentication and unlocking through the Internet. This method is widely used in time-sharing rental and shared charging market, such as patent CN109219036A "electric vehicle charging system and method based on mobile terminal control" puts forward the identity control mechanism combined with mobile terminal and background server; (3) biological feature (such as fingerprint, face) recognition technology: in some high-end private charging piles, biological recognition means is applied to control unlocking operation, which improves the equipment specificity and convenience. This method has higher requirements for environment, cost and use conditions, and is less popular in public places.

[0003] Although the above-mentioned technologies have certain application in charging pile management, they all have different degrees of limitations: (1) relying on manual intervention: users need to actively swipe cards, operate mobile phones or accept biometric identification, which is difficult to adapt to automatic driving or unattended scenarios; (2) authentication media is easy to lose or be copied: cards, APP credentials, fingerprints and other identity identifiers are easy to be stolen or forged, which poses a security risk; (3) high system complexity and network dependence: the APP / cloud platform-based method relies heavily on the network, has poor stability, and has high deployment and maintenance costs; (4) human-vehicle separation authentication limits management efficiency: especially when managing multiple vehicles in enterprises / institutions, the user and vehicle identities are not clearly bound, and it is not possible to achieve automatic control of "vehicle as identity". In addition, some academic research attempts to identify identity from the physical layer or signal layer. The literature "A Physical Layer Authentication Scheme for Electric Vehicle Charging Systems Based on Signal Features" proposes to extract device fingerprints by waveform features of voltage and current signals during charging to achieve authentication. However, this method cannot achieve active signal transmission and parameter setting, is limited to passive measurement and differentiation, and is not suitable for fast and dynamic dedicated vehicle authentication requirements.

[0004] In summary, there is currently no technology that can implement an intelligent unlocking method that uses the vehicle itself as the authentication subject and implicitly transmits "identity information" in the form of a modulated signal through the charging line. Therefore, developing an intelligent unlocking device that actively transmits key parameters through a modulated signal from the vehicle end, and performs identity verification and control after demodulation and identification at the charging pile end, has important application value and practical needs. Content of the utility model

[0005] The utility model discloses a modulated signal authentication unlocking device for private charging pile, generates modulated signal at electric automobile end and transmits to the pile end for demodulation and identification through charging lead, can effectively realize vehicle autonomous identity authentication, significantly improves the automation, security and adaptability of charging process.

[0006] A modulated signal authentication unlocking device for private charging pile includes the following components: a vehicle-end modulated signal sending module, a charging lead transmission channel, a pile-end signal preprocessing module, a signal sampling and processing module, an authentication decision and control module, and a control execution unit.

[0007] The vehicle-end modulated signal sending module is arranged at the vehicle end and generates a modulated signal carrying an identity key.

[0008] The charging lead transmission channel co-transmits the signal output by the vehicle-end modulated signal sending module and charging electric energy to the pile end.

[0009] The pile end signal preprocessing module is arranged at the charging pile end and is composed of a band-pass filter and a signal amplification circuit.

[0010] The signal sampling and processing module is arranged at the charging pile end and is provided with an FPGA and an STM32 embedded processing platform.

[0011] The authentication decision and control module is arranged at the charging pile end, compares the parsed signal parameters with preset key parameters and outputs an authentication decision result.

[0012] The control execution unit is arranged at the charging pile end and executes an unlocking or locking action according to the authentication decision result.

[0013] The vehicle end modulation signal sending module is connected with the pile end signal preprocessing module through a charging cable transmission channel.

[0014] Further, the vehicle end modulation signal sending module uses a microcontroller unit to output preset binary key information and modulates the binary key information through a modulation chip; the binary key information contains a vehicle identification code.

[0015] Further, the microcontroller unit in the vehicle end modulation signal sending module controls the modulation type to correspond to the key.

[0016] Further, the charging cable transmission channel uses a direct current charging cable to perform signal and power co-linear transmission, and a high-frequency signal is transmitted in a common mode manner through a cable distribution capacitor.

[0017] Further, the signal sampling and processing module is provided with an FPGA and an STM32 embedded processing platform, uses the FPGA to perform ADC driving and sampling control, performs fast Fourier transform on the sampled signal to extract a frequency spectrum, and uses the STM32 to perform data analysis and extract modulation parameters.

[0018] Further, the authentication decision and control module is preset with authentication parameters at the pile end, compares the signal parameters obtained through STM32 analysis and identification with preset key parameters in the charging pile to make an authentication decision; if all parameters are matched within a tolerance range, it is determined that the authentication is successful, and if any parameter does not match the key, it is determined that the authentication fails.

[0019] Further, when the authentication decision and control module succeeds in authentication, the control execution unit executes an unlocking and starting charging command to drive a relay to close and open an electromagnetic lock; if the authentication decision and control module fails in authentication, the control execution unit maintains a locking state.

[0020] Compared with the prior art, the utility model can achieve the following beneficial effects:

[0021] (1) The utility model discloses a vehicle end active emission modulation signal carries identity key information, makes the vehicle body become the authentication main body, realizes the vehicle autonomous identity authentication, solves the problem that the authentication must be carried out by the specific personnel with medium in the prior art, is applicable to company fleet, shared car, unmanned driving etc.

[0022] (2) The utility model discloses an authentication process without manual operation, without scanning code, card swiping or networking operation, can realize parking charging, automatic judgment, automatic unlocking, improves the system automation degree, effectively improves user experience and use efficiency.

[0023] (3) The utility model discloses an authentication signal in the form of high-frequency low-amplitude modulation signal is superimposed on the charging wire, does not depend on wireless channel, and the physical layer transmission path is closed, reduces the risk of being tampered with or man-in-the-middle attack, has authentication concealment and anti-interference ability, effectively improves system security.

[0024] (4) The utility model discloses an authentication process not dependent on Wi-Fi, Bluetooth, 4G / 5G etc. Communication network, does not involve additional server or cloud platform, reduces communication module configuration, reduces system complexity and dependency, reduces system construction and maintenance cost.

[0025] (5) The utility model discloses a system that supports AM, FM, ASK, FSK, PSK etc. Multiple modulation modes, and can construct multiple keys through frequency, amplitude, code rate etc. Parameter combination, has good expansibility and compatibility. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is the modulation signal authentication unlocking device schematic drawing for private charging pile that the utility model discloses proposes. DETAILED DESCRIPTION

[0027] The specific embodiments of the utility model are further explained below in combination with the drawings, and the technical scheme in the embodiment of the utility model is clearly and completely described, obviously, the described embodiment is only a part of the embodiment of the utility model, not all the embodiment. Based on the embodiment in the utility model, all other embodiments obtained by the person skilled in the art without making creative labor belong to the scope of protection of the utility model.

[0028] In combination Figure 1 A modulation signal authentication unlocking device for private charging pile, characterized in that it comprises the following components: a vehicle-end modulation signal sending module, a charging wire transmission channel, a pile-end signal preprocessing module, a signal sampling and processing module, an authentication decision and control module, and a control execution unit.

[0029] The vehicle-end modulation signal sending module is arranged at the vehicle end and generates a modulation signal carrying an identity key.

[0030] The charging wire transmission channel co-transmits the signal output by the vehicle-end modulation signal sending module and charging electric energy to the pile end;

[0031] The pile-end signal preprocessing module is arranged at the charging pile end and is composed of a band-pass filter and a signal amplification circuit;

[0032] The signal sampling and processing module is arranged at the charging pile end and is provided with an FPGA and an STM32 embedded processing platform;

[0033] The authentication decision and control module is arranged at the charging pile end, compares the analyzed signal parameters with a preset key, and outputs an authentication decision result;

[0034] The control execution unit is arranged at the charging pile end and performs an unlocking or locking action according to the authentication decision result;

[0035] The vehicle-end modulation signal sending module is connected to the pile-end signal preprocessing module through the charging wire transmission channel.

[0036] Further, the vehicle-end modulation signal sending module uses a microcontroller unit to output a preset binary key information, modulates the binary key information into an AM signal, an FM signal, an ASK signal, an FSK signal, and a PSK signal through a modulation chip, and outputs a carrier frequency of 2 MHz and a peak-to-peak value of 100 mV; the modulation process follows the classical modulation theory:

[0037] The expression of the AM signal is:

[0038] s(t)=A c [1+m·cos(2πf m t)]·cos(2πf c t)

[0039] wherein A c is the carrier amplitude, f m is the frequency of the modulation signal, f c is the carrier frequency, and m is the amplitude modulation coefficient;

[0040] The FM signal is expressed as:

[0041] s(t)=A c cos[2πf c t+2πk f ∫m(t)dt]

[0042] wherein k f is the frequency modulation sensitivity;

[0043] Other ways (such as FSK, PSK) are realized by frequency or phase discrete jump modulation, and these modulation signals have good low power, high information density and anti-interference performance, which are suitable for transmission in shared conductors.

[0044] Further, the microcontroller unit in the vehicle end modulation signal sending module controls the modulation type corresponding to the key.

[0045] Further, the charging conductor transmission channel uses a direct current charging cable for signal and power co-linear transmission, and the high-frequency signal is transmitted in a common mode manner through the cable distribution capacitor.

[0046] Further, the signal sampling and processing module sets an FPGA and an STM32 embedded processing platform, uses the FPGA for ADC driving and sampling control, performs fast Fourier transform on the sampling signal to extract the frequency spectrum, and transforms the time domain signal into the frequency domain, and the expression is:

[0047]

[0048] Wherein, X(k) is a frequency domain signal, x(n) is a time domain signal, N is the length of a time domain sequence, e -j2πkn / N is a rotation factor, k is the index of the frequency domain, n is the index of the time domain, and j is the imaginary unit;

[0049] The AM signal is represented as a main peak + symmetric sideband;

[0050] The FSK signal is represented as a double main frequency peak;

[0051] The FM signal is represented as a broadened spectrum, and the spectrum line is irregular;

[0052] The PSK signal spectrum has a sudden phase point;

[0053] The STM32 is used to perform data analysis, extract modulation parameters, and use threshold decision, edge detection, integral envelope and other algorithms to extract:

[0054] Amplitude modulation coefficient:

[0055] Wherein, A max is the maximum amplitude value of the amplitude modulation signal, A min is the minimum amplitude value of the amplitude modulation signal;

[0056] Frequency modulation frequency offset: Δf=f max -f c

[0057] Wherein, f max is the maximum instantaneous frequency of the frequency modulation signal, and f c is the carrier frequency;

[0058] Rate estimation: based on adjacent signal mutation interval statistics;

[0059] Further, the authentication decision and control module pre-set authentication parameters at the pile end, and the signal parameters obtained by the STM32 analysis and identification are authenticated with the pre-set key parameters in the charging pile.

[0060] Further, the authentication decision and control module pre-set authentication parameters at the pile end, and the signal parameters obtained by the STM32 analysis and identification are authenticated with the pre-set key parameters in the charging pile.

[0061] The working principle of the utility model is divided into the following steps: (1) the vehicle inserts the charging gun; (2) the vehicle end modulation signal sending module automatically sends the modulation signal (including the key) ; (3) the signal is transmitted to the pile end through the charging wire transmission channel; (4) the pile end signal preprocessing module carries out filtering, amplification and sampling; (5) the signal sampling and processing module identifies the modulation mode based on FPGA; (6) the authentication decision and control module carries out parameter estimation and key matching based on STM32; (7) if the authentication is successful, the control execution unit executes the unlocking and starting charging command; if the authentication fails, it prompts to refuse charging, and the control execution unit maintains the locking state.

[0062] The above is only the preferred embodiment of the application, and the utility model is not limited to the above examples. It can be understood that other improvements and changes directly derived or thought of by those skilled in the art without departing from the spirit and concept of the utility model should be considered to be included in the protection scope of the utility model.

Claims

1. A modulation signal authentication and unlocking device for private charging piles, characterized in that, It includes the following components: vehicle-side modulation signal transmission module, charging cable transmission channel, pile-side signal preprocessing module, signal sampling and processing module, authentication decision and control module, and control execution unit; The vehicle-side modulation signal transmission module is installed at the vehicle end to generate a modulation signal carrying an identity key; The charging cable transmission channel transmits the signal output from the vehicle-side modulation signal transmission module and the charging power along the same line to the charging pile. The charging pile signal preprocessing module is located at the charging pile end and consists of a bandpass filter and a signal amplification circuit. The signal sampling and processing module is set at the charging pile end, using an FPGA and STM32 embedded processing platform. The authentication decision and control module is set at the charging pile end, compares the parsed signal parameters with the preset key and outputs the authentication decision result; The control execution unit is located at the charging pile end and performs unlocking or locking actions based on the authentication judgment result; The vehicle-side modulation signal transmission module is connected to the pile-side signal preprocessing module via a charging cable transmission channel.

2. The modulation signal authentication and unlocking device for a private charging station according to claim 1, characterized in that, The vehicle-side modulation signal transmission module uses a microcontroller unit to output preset binary key information, and modulates the binary key information through a modulation chip; the binary key information includes a vehicle identification code.

3. The modulation signal authentication and unlocking device for a private charging station according to claim 1, characterized in that, In the vehicle-side modulation signal transmission module, the microcontroller unit controls the modulation type to correspond to the key.

4. The modulation signal authentication and unlocking device for a private charging station according to claim 1, characterized in that, The charging wire transmission channel uses a DC charging cable for signal and power co-line transmission, and high-frequency signals are transmitted in common mode through the cable's distributed capacitance.

5. A modulation signal authentication and unlocking device for a private charging station according to claim 1, characterized in that, The signal sampling and processing module is equipped with an FPGA and an STM32 embedded processing platform. The FPGA is used for ADC driving and sampling control, the sampled signal is subjected to fast Fourier transform to extract the spectrum, and the STM32 is used to perform data parsing to extract modulation parameters.

6. A modulation signal authentication and unlocking device for a private charging station according to claim 1, characterized in that, The authentication decision and control module presets authentication parameters at the charging pile end and performs authentication decision by comparing the signal parameters obtained by STM32 parsing with the preset key parameters in the charging pile. If all parameters match within the tolerance range, the authentication is deemed successful; if any parameter does not match the key, the authentication is deemed unsuccessful.

7. A modulation signal authentication and unlocking device for a private charging station according to claim 1, characterized in that, If the authentication decision and control module authentication are successful, the control execution unit executes the unlock and start charging commands, drives the relay to close, and opens the electromagnetic lock; if the authentication decision and control module authentication fail, the control execution unit maintains the locked state.

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