A passive lock and system based on NFC and wireless power supply technology

Abstract

The utility model discloses a passive lock and system based on NFC and wireless power supply technique, including wireless power supply circuit, NFC circuit, singlechip circuit, lock driving circuit, lock switch state monitoring circuit and lock, and lock driving circuit controls the opening or closing of lock under the instruction of MCU, and through lock switch state monitoring circuit real -time detection lock's state, exports feedback signal to singlechip circuit. The utility model discloses through NFC security identity authentication mechanism, realizes intelligent management, can fast deployment, and maintenance cost is low, and moreover adopts wireless power supply when working, need not battery or wired power supply, and the working time is long.

Description

Technical Field

[0001] This utility model belongs to the field of substation safety equipment technology, specifically relating to a passive lock and system based on NFC and wireless power supply technology. Background Technology

[0002] With the increasing demand for intelligent upgrades in substations, the limitations of traditional mechanical locks and existing electronic lock technologies are no longer sufficient to meet the requirements of modern distribution cabinet safety management and efficient operation and maintenance. Existing active electronic locks rely on batteries or external power supplies, making them prone to failure due to power outages in harsh outdoor environments, and they also incur high maintenance costs. While existing passive locks do not require power, most lack integrated wireless communication modules or standardized interfaces, making it difficult to work collaboratively with robots, smart terminals, and other devices, thus limiting the flexibility and response speed of distribution cabinet operations. Therefore, there is an urgent need for a new type of passive electronic lock that can solve core problems such as chaotic key management, low operation and maintenance efficiency, and the lack of intelligent linkage. Utility Model Content

[0003] Technical Objective: To address the aforementioned technical problems, this utility model proposes a passive lock and system based on NFC and wireless power supply technology. It achieves intelligent management through the NFC secure authentication mechanism, enabling rapid deployment and low maintenance costs. Moreover, it uses wireless power supply during operation, eliminating the need for batteries or wired power, and has a long working time.

[0004] Technical solution: To achieve the above technical objectives, the present invention adopts the following technical solution:

[0005] A passive lock based on NFC and wireless power supply technology includes: a wireless power supply circuit, an NFC circuit, a microcontroller circuit, a lock drive circuit, a lock switch status monitoring circuit, and a lock.

[0006] The wireless power supply circuit provides operating power for the NFC circuit, the microcontroller circuit, the lock drive circuit, and the lock switch status monitoring circuit.

[0007] The NFC circuit includes an NFC coil, an NFC chip, and a matching circuit.

[0008] The microcontroller circuit includes an MCU, a clock circuit, and a reset circuit. The input terminal of the MCU is connected to the output terminal of the NFC circuit, and the output terminal of the MCU is connected to the input terminal of the lock driving circuit.

[0009] The output terminal of the lock drive circuit is connected to the lock, driving the lock to open or close;

[0010] The lock switch status monitoring circuit is used to detect the status of the lock in real time, and the output is connected to the input terminal of the MCU.

[0011] Preferably, the wireless power supply circuit includes a wireless power supply receiving coil, a rectifier circuit, a voltage regulator module, and an energy storage circuit connected in sequence.

[0012] Preferably, the wireless power supply circuit includes: a third inductor, a first resistor, a fourth capacitor, a first diode, a fifth capacitor, a first driver, a third diode, a first inductor, a third resistor, a fourth resistor, a twelfth capacitor, a thirteenth capacitor, and a fourteenth capacitor. The third inductor serves as a wireless power supply receiving coil, with its first end connected to the anode of the first diode and its second end grounded via the first resistor. The first driver uses an XKT 3202 chip, with the cathode of the first diode connected to the IS pin of the first driver. The first end of the fourth capacitor is connected to the anode of the first diode, and its second end is grounded. The first end of the fifth capacitor is connected to the VIN pin of the first driver, and its second end is grounded. The OUT pin of the first driver is simultaneously connected to the cathode of the third diode and the first end of the first inductor. The anode of the third diode is grounded. The second end of the first inductor is connected to the first end of the third resistor, and the second end of the third resistor and the first end of the fourth resistor are grounded. The twelfth, thirteenth, and fourteenth capacitors are connected in parallel as an energy storage circuit, with the first end of the twelfth capacitor connected to the first end of the third resistor and the second end of the twelfth capacitor connected to the second end of the fourth resistor.

[0013] Preferably, the NFC chip is an ST25DV04K chip, the MCU is an STM32F microcontroller, the VDD pin of the NFC chip is connected to the PA6 pin of the MCU, and the lock switch status monitoring circuit includes two GT-MPU217-H253 microswitches.

[0014] Preferably, the lock includes a motor and a bolt, the lock drive circuit includes a motor drive chip and a motor protection circuit, and the lock switch status monitoring circuit is equipped with a micro switch for real-time detection of the bolt position.

[0015] Preferably, the motor driver chip is model CJDR911, and the IN1 and IN2 pins of the motor driver chip are connected to the control signal output pins PA1 and PA2 of the MCU.

[0016] Preferably, the lock uses an electronic switch with contacts, the lock drive circuit includes a relay and a relay control circuit, the relay controls the closing and opening of the contacts, and the lock switch status monitoring circuit is set to detect the status of the contacts in real time.

[0017] Preferably, the lock includes a micro pump and a piston structure, the lock drive circuit includes a micro pump control circuit, and the lock switch status monitoring circuit is configured to detect the position of the piston structure in real time.

[0018] A passive lock system based on NFC and wireless power supply technology includes a user-end card reader and the passive lock.

[0019] Beneficial effects: Due to the adoption of the above technical solution, this utility model has the following beneficial effects:

[0020] The passive lock system proposed in this utility model is equipped with NFC and MCU modules. It achieves intelligent management through NFC security authentication mechanism, can be linked with robots for authorized unlocking, can be quickly deployed, has low maintenance cost, and uses wireless power supply during operation, eliminating the need for batteries or wired power supply, and can operate for a long time with real-time power supply. Attached Figure Description

[0021] Figure 1 This is a circuit block diagram of this utility model;

[0022] Figure 2 This is a schematic diagram of a wireless power supply circuit example;

[0023] Figure 3 This is a schematic diagram of an NFC circuit example;

[0024] Figure 4 This is a schematic diagram of a microcontroller circuit example;

[0025] Figure 5 This is a schematic diagram of an example of a lock drive circuit;

[0026] Figure 6 This is a schematic diagram of the feedback circuit for opening the lock;

[0027] Figure 7 This is a schematic diagram of the feedback circuit for locking.

[0028] Figure 8 This is a schematic diagram of a passive lock applied to a power distribution cabinet in scenario 1.

[0029] Figure 9 This is a schematic diagram of a passive lock applied to a power distribution cabinet in scenario 2.

[0030] Wherein, R1 is the first resistor; R3 is the third resistor; R4 is the fourth resistor; R7 is the seventh resistor; R8 is the eighth resistor; R13 is the thirteenth resistor; R14 is the fourteenth resistor; R15 is the fifteenth resistor; R16 is the sixteenth resistor; R19 is the nineteenth resistor; R20 is the twentieth resistor; R23 is the twenty-third resistor; R17 is the seventeenth resistor; R27 is the twenty-seventh resistor; R30 is the thirtieth resistor; and R31 is the thirty-first resistor.

[0031] C1, First capacitor; C2, Second capacitor; C3, Third capacitor; C4, Fourth capacitor; C5, Fifth capacitor; C8, Eighth capacitor; C12, Twelfth capacitor; C13, Thirteenth capacitor; C14, Fourteenth capacitor; C15, Fifteenth capacitor; C16, Sixteenth capacitor; C18, Eighteenth capacitor; C19, Nineteenth capacitor; C21, Twenty-first capacitor; C22, Twenty-second capacitor; C24, Twenty-fourth capacitor; C25, Twenty-fifth capacitor; C26, Twenty-sixth capacitor; C29, Twenty-ninth capacitor;

[0032] D1, driver; D2, NFC chip; D4, MCU; D7, motor driver chip; VD1, first diode; VD3, third diode; L1, first inductor; L3, third inductor; G1, oscillator. Detailed Implementation

[0033] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0034] Example 1

[0035] like Figure 1 As shown, this embodiment proposes a passive lock system based on NFC and wireless power supply technology, which mainly includes the following modules:

[0036] Wireless power supply circuit: Composed of an RF energy receiving antenna, a rectifier circuit (AC-DC), an energy storage capacitor, and a voltage regulator module. It uses RF field energy harvesting technology to convert the electromagnetic wave energy of the external card reader into DC power to power the system (no battery required). Figure 2 As shown, it provides power to modules such as the NFC circuit, microcontroller, and motor driver.

[0037] NFC circuit: Composed of an NFC chip, matching circuit, and antenna. It is used for energy reception, receiving radio frequency energy from an external card reader, such as... Figure 3 As shown, it includes an ST25DV04K NFC chip and its peripheral circuitry. It enables bidirectional communication for data exchange with the card reader (such as authentication and command transmission).

[0038] A microcontroller circuit consists of a low-power MCU, a clock circuit, and a reset circuit, such as... Figure 4 As shown, it includes an STM32F microcontroller and its peripheral circuitry. It is used to parse NFC-transmitted commands (such as unlock / lock requests), control the motor drive circuit, process lock status monitoring signals, and execute encryption algorithms (such as AES-128) to verify permissions.

[0039] Lock drive circuit: In this embodiment, it is preferably designed as a motor drive circuit, consisting of an H-bridge driver chip and a motor protection circuit, such as... Figure 5As shown. The lock includes a motor and a bolt. The micro motor (such as a stepper motor or a DC geared motor) is driven according to MCU instructions to perform the extension and retraction of the bolt.

[0040] Lock switch status monitoring circuit: Real-time detection of the bolt position (unlocked status signal S_OUT / locked status signal S_IN) via a microswitch, and feedback the status signal to the MCU, such as... Figure 6 and Figure 7 As shown.

[0041] The wireless power supply circuit requires an external coil to couple energy, and then the circuit rectifies and steps down the voltage to output 3.3V to power the entire system (including the NFC chip, microcontroller, and motor driver).

[0042] Specifically, Figure 2 As shown, the wireless power supply circuit includes: a third inductor L3, a first resistor R1, a fourth capacitor C4, a first diode VD1, a fifth capacitor C5, a first driver D1, a third diode VD3, a first inductor L1, a third resistor R3, a fourth resistor R4, a twelfth capacitor C12, a thirteenth capacitor C13, and a fourteenth capacitor C14. The third inductor L3 serves as the wireless power supply receiving coil. The first terminal of the third inductor L3 is connected to the positive terminal of the first diode VD1, and the second terminal is grounded via the first resistor R1. The first driver D1 is an XKT type... In the 3202 chip, the cathode of the first diode VD1 is connected to the IS pin of the first driver D1; the first terminal of the fourth capacitor C4 is connected to the anode of the first diode VD1, and the second terminal is grounded; the first terminal of the fifth capacitor C5 is connected to the VIN pin of the first driver D1, and the second terminal is grounded; the OUT pin of the first driver D1 is simultaneously connected to the cathode of the third diode VD3 and the first terminal of the first inductor L1, the anode of the third diode VD3 is grounded, the second terminal of the first inductor L1 is connected to the first terminal of the third resistor R3, and the second terminal of the third resistor R3 and the first terminal of the fourth resistor are grounded; the twelfth capacitor C12, the thirteenth capacitor C13, and the fourteenth capacitor C14 are connected in parallel as an energy storage circuit, the first terminal of the twelfth capacitor C12 is connected to the first terminal of the third resistor R3, and the second terminal of the twelfth capacitor C12 is connected to the second terminal of the fourth resistor R4.

[0043] Figure 3 and Figure 4 As shown, the NFC chip D2 is an ST25DV04K chip, and the MCU (D4) is an STM32F microcontroller. The VDD pin of the NFC chip D2 is connected to the PA6 pin of the MCU.

[0044] Figure 5 and Figure 6As shown, the motor driver chip D7 is model CJDR911. The IN1 and IN2 pins of the motor driver chip D7 are connected to the MCU's control signal output pins PA1 and PA2. The lock switch status monitoring circuit includes two microswitches, model GT-MPU217-H253, which are connected to the MCU's pins PA4 and PA3 respectively.

[0045] Example 2

[0046] This utility model proposes a passive lock system, including a user-end card reader (i.e., smart card / key) and the passive lock proposed in Embodiment 1. An external universal NFC coil is connected to the NFC circuit to receive data coupled to the key end, via I... 2 The C protocol transmits data to the microcontroller, which executes commands issued by the key, controls the motor driver to drive the motor, and uses the lock switch status detection circuit to determine the current lock status. This is done via I / O. 2 The C protocol transmits data to the NFC chip, which then reports the current status to the key via a coil. The key obtains its identity information via NFC and then sends an unlock or lock command to the microcontroller. The microcontroller controls the driver to drive the motor forward or reverse, and then obtains the lock's status to inform the key, forming a closed-loop control system.

[0047] The specific unlocking and locking procedures are as follows.

[0048] 1. Unlocking process:

[0049] When a user swipes their card, the wireless power supply circuit receives radio frequency energy and converts electromagnetic wave energy into DC power.

[0050] NFC circuit activated, MCU starts;

[0051] The MCU reads data from the NFC chip, and the security module in the MCU verifies permissions.

[0052] Verification passed, motor drive circuit started, and latch retracted;

[0053] The lock switch status monitoring circuit confirms that the unlocking is complete, and the MCU sends back a successful unlocking signal.

[0054] The MCU enters low-power mode and awaits the next command to activate it.

[0055] 2. Locking procedure:

[0056] When a user swipes their card, the wireless power supply circuit receives radio frequency energy and converts electromagnetic wave energy into DC power.

[0057] The NFC circuit activates the system, and the MCU starts up.

[0058] The MCU reads data from the NFC chip, and the security module in the MCU verifies permissions.

[0059] Verification passed, motor drive circuit started, and bolt extended;

[0060] The lock switch status monitoring circuit confirms that the locking is complete, and the MCU sends back a lock success signal.

[0061] The MCU enters low-power mode and awaits the next command to activate it.

[0062] This utility model's solution uses an NFC secure authentication mechanism to record information, with each lock having a unique ID. One key can open multiple locks, and it can be linked with robots for authorized unlocking. It can be deployed quickly, has low maintenance costs, and is wirelessly powered during operation, eliminating the need for batteries or wired power. It also provides real-time power for extended operation.

[0063] The methods for waking up the wireless power supply circuit and the NFC circuit are as follows:

[0064] When the user brings the passive lock key device (dedicated key) close to the lock (distance ≤1cm), the lock's built-in wireless power supply receiver coil and NFC coil receive the radio frequency energy emitted by the key device (wireless power supply frequency 170KHz, NFC frequency 13.56MHz, power ≤3W). Energy conversion efficiency ≥70%, wake-up time ≤0.2 seconds. No battery required, achieving zero-power standby.

[0065] The methods for identity authentication and command transmission are as follows:

[0066] The lock has a built-in NFC (model: ST25DV04K-JFR8D3) chip and MCU (model: STM32F030F4P6) to establish communication with the user's key device and verify the dynamic encryption key (AES-128 algorithm).

[0067] Communication rate 106kbps, authentication response time ≤0.3 seconds.

[0068] The false recognition rate is <0.01%.

[0069] The method for unlocking the motor drive is as follows:

[0070] After authentication, the MCU sends an unlocking command to the motor driver chip. The driver drives the DC motor, which in turn drives the bolt to the designated unlocking position via gears. A micro switch is used to monitor whether the bolt is in position.

[0071] Unlocking action time ≤ 5 seconds, single unlocking power consumption ≤ 0.1J.

[0072] Low-power drive, meeting the requirement of over 1000 unlock cycles.

[0073] The methods for power outages and energy saving are as follows:

[0074] After unlocking is complete, the MCU reports the lock status to the user's key. Once the key leaves the lock, the lock enters a power-off state and remains in this state.

[0075] Power outage time ≤ 1 second, sleep power consumption 0μA.

[0076] Currently, NFC-based passive locks on the market can only drive the motor for about 1 second, but in an increasing number of scenarios, the motor needs to operate continuously for about 7-8 seconds. This invention addresses the energy supply issue by optimizing and resolving the following methods: selecting high-power energy-capturing NFC chips and read / write chips, using suitable energy storage capacitors, calculating motor torque to select appropriate motors and reducers, adjusting operating time, designing PCB antennas to adjust coupling efficiency, and ultimately debugging to achieve reasonable parameters that meet the application scenarios of various passive locks.

[0077] The wireless power supply + NFC combination technology proposed in this utility model has the following advantages:

[0078] 1. Enhanced power output: Combined with radio magnetic field transmission technology, the power supply can reach 5-10W or more, which is 5-10 times more efficient than traditional NFC power supply. It can support lock body structures with higher power consumption, such as motor-driven bolts with longer travel; and motors with higher power can open and close locks faster.

[0079] 2. Continuous Power Supply: Dynamic power regulation is achieved through high-frequency radio frequency technology, avoiding power instability caused by insufficient mobile phone battery, and ensuring stable unlocking in complex scenarios.

[0080] 3. Different unlocking methods: Traditional NFC passive locks can only achieve semi-automatic unlocking, meaning that after unlocking with a mobile phone, the lock still needs to be manually locked, and automation is not possible. The lock designed in this utility model uses wireless power supply, and can automatically open and close the lock when the battery is sufficient.

[0081] In this invention, the lock's driving method is not limited to using a motor-driven gear combination; it can be replaced by an electromagnet drive, a pneumatic / hydraulic drive (micro-pump + piston structure), etc.

[0082] Scenario 1 for passive lock on distribution cabinet: Figure 8 As shown, the internal motor drives the bolt to extend and retract to block the knife switch operating eye, thus achieving the purpose of locking.

[0083] Scenario 2 for passive locks on distribution cabinets: Figure 9 As shown, the passive lock has two contacts that are connected to the electronic switch contacts. The control relay inside the lock controls the electronic switch by engaging and disengaging to achieve the purpose of locking, saving manpower and avoiding misoperation.

[0084] In this invention, the passive lock power supply scheme is not limited to dedicated electromagnetic induction power supply (coil coupling), but can be replaced by NFC power supply, radio frequency energy harvesting (RF energy harvesting chip, such as Powercast module), piezoelectric effect power supply (mechanical vibration is converted into electrical energy), etc.

[0085] Communication methods are not limited to NFC (13.56MHz) and can be replaced by RFID (125kHz or 900MHz), Wi-Fi HaLow (low-power long-range communication), LoRa (long-range low-power communication), Bluetooth Low Energy (BLE), etc. Antennas are not limited to coil-wound antennas and can be replaced by flexible FPC antennas, ceramic antennas, PCB printed antennas, etc.

[0086] Identity authentication methods are not limited to one-way authentication using NFC chips. They can be replaced by two-way encrypted authentication (such as AES-128 dynamic key), biometric authentication (fingerprint / NFC composite module), voiceprint recognition (microphone + voice processing chip), etc.

[0087] The above description is only a preferred embodiment of the present utility model. It should be noted that the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A passive lock based on NFC and wireless power supply technology, characterized in that, include: Wireless power supply circuit, NFC circuit, microcontroller circuit, lock drive circuit, lock switch status monitoring circuit and lock; The wireless power supply circuit provides operating power for the NFC circuit, the microcontroller circuit, the lock drive circuit, and the lock switch status monitoring circuit. The NFC circuit includes an NFC coil, an NFC chip, and a matching circuit. The microcontroller circuit includes an MCU, a clock circuit, and a reset circuit. The input terminal of the MCU is connected to the output terminal of the NFC circuit, and the output terminal of the MCU is connected to the input terminal of the lock driving circuit. The output terminal of the lock drive circuit is connected to the lock, driving the lock to open or close; The lock switch status monitoring circuit is used to detect the status of the lock in real time, and the output is connected to the input terminal of the MCU.

2. A passive lock based on NFC and wireless power supply technology according to claim 1, characterized in that, The wireless power supply circuit includes a wireless power receiving coil, a rectifier circuit, a voltage regulator module, and an energy storage circuit connected in sequence.

3. A passive lock based on NFC and wireless power supply technology according to claim 2, characterized in that: The wireless power supply circuit includes: a third inductor, a first resistor, a fourth capacitor, a first diode, a fifth capacitor, a first driver, a third diode, a first inductor, a third resistor, a fourth resistor, a twelfth capacitor, a thirteenth capacitor, and a fourteenth capacitor. The third inductor serves as the wireless power supply receiving coil, with its first end connected to the anode of the first diode and its second end grounded via the first resistor. The first driver uses an XKT 3202 chip, with the cathode of the first diode connected to the IS pin of the first driver. The first end of the fourth capacitor is connected to the anode of the first diode, and its second end is grounded. The first end of the fifth capacitor is connected to the VIN pin of the first driver, and its second end is grounded. The OUT pin of the first driver is simultaneously connected to the cathode of the third diode and the first end of the first inductor. The anode of the third diode is grounded. The second end of the first inductor is connected to the first end of the third resistor, and the second ends of the third resistor and the first ends of the fourth resistor are grounded. The twelfth, thirteenth, and fourteenth capacitors are connected in parallel as an energy storage circuit, with the first end of the twelfth capacitor connected to the first end of the third resistor and the second end of the twelfth capacitor connected to the second end of the fourth resistor.

4. A passive lock based on NFC and wireless power supply technology according to claim 1, characterized in that: The NFC chip is an ST25DV04K chip, and the MCU is an STM32F microcontroller. The VDD pin of the NFC chip is connected to the PA6 pin of the MCU. The lock switch status monitoring circuit includes two GT-MPU217-H253 microswitches.

5. A passive lock based on NFC and wireless power supply technology according to claim 1, characterized in that: The lock includes a motor and a bolt. The lock drive circuit includes a motor drive chip and a motor protection circuit. The lock switch status monitoring circuit is equipped with a micro switch that detects the position of the bolt in real time.

6. A passive lock based on NFC and wireless power supply technology according to claim 5, characterized in that: The motor driver chip is model CJDR911. The IN1 and IN2 pins of the motor driver chip are connected to the control signal output pins PA1 and PA2 of the MCU.

7. A passive lock based on NFC and wireless power supply technology according to claim 1, characterized in that: The lock uses an electronic switch with contacts. The lock drive circuit includes a relay and a relay control circuit. The relay controls the closing and opening of the contacts. The lock switch status monitoring circuit is set to detect the status of the contacts in real time.

8. A passive lock based on NFC and wireless power supply technology according to claim 1, characterized in that: The lock includes a micro pump and a piston structure. The lock drive circuit includes a micro pump control circuit and a lock switch status monitoring circuit that is set to detect the position of the piston structure in real time.

9. A passive lock system based on NFC and wireless power supply technology, characterized in that: Includes a user-end card reader and a passive lock as described in any one of claims 1-8.

Images