Passive wireless temperature measurement circuit

Abstract

The utility model relates to the technical field of power equipment environment monitoring, in particular to a passive wireless temperature measurement circuit, which comprises an electric energy acquisition module, a voltage monitoring module, a voltage stabilizing module, a micro-control module, a temperature sensing module and a radio frequency module, the voltage monitoring module is electrically connected with the control end of the voltage stabilizing module, the micro-control module is electrically connected with the output end of the voltage stabilizing module, the temperature sensing module and the radio frequency module, and the electric energy acquisition module is used for acquiring electric energy from an alternating current bus to provide continuous electric power; the voltage monitoring module is used for monitoring the output voltage of the electric energy acquisition module in real time to ensure the power supply stability and safety of the system; the voltage stabilizing module is used for providing stable voltage; the micro-control module is responsible for data acquisition and processing; the micro-control module is electrically connected with the radio frequency module and is used for realizing wireless communication; the temperature sensing module is used for monitoring the change of the environment temperature.

Description

Technical Field

[0001] The utility model relates to the technical field of power equipment environment monitoring, in particular to a passive wireless temperature measurement circuit. Background Art

[0002] Currently, there are two ways to monitor the power equipment environment:

[0003] 1. Passive RFID temperature sensors rely on external readers for power. When the reader approaches, the sensor obtains energy from the external radio frequency signal and measures temperature and humidity. Although this type of sensor does not require battery power, its monitoring distance is limited. It is usually only suitable for short-distance, non-continuous monitoring scenarios and is not suitable for high-voltage, low-voltage, and high-current environments that require long-term, real-time monitoring.

[0004] High-voltage power equipment monitoring systems typically integrate multiple sensors to monitor electrical parameters and environmental conditions within substations or transmission lines. These systems typically offer good stability and adaptability, but they are complex and costly, and can be difficult to deploy for monitoring small or distributed electrical equipment. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a passive wireless temperature measurement circuit, which can realize efficient and reliable environmental monitoring to improve the safety and working efficiency of equipment.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A passive wireless temperature measurement circuit includes an electric energy acquisition module, a voltage monitoring module, a voltage stabilization module, a microcontroller module, a temperature sensing module and a radio frequency module. The electric energy acquisition module is electrically connected to the input end of the voltage stabilization module, the voltage monitoring module is electrically connected to the control end of the voltage stabilization module, and the microcontroller module is electrically connected to the output end of the voltage stabilization module, the temperature sensing module and the radio frequency module respectively.

[0008] Furthermore, the electric energy collection module includes a current transformer T1, a diode D1 and a diode D2, one end of the current transformer T1 is electrically connected to the cathode of the diode D1 and the anode of the diode D2, respectively, the other end of the current transformer T1 is electrically connected to the anode of the diode D1 and the ground end of the voltage stabilizing module, and the cathode of the diode D2 is electrically connected to the input end of the voltage stabilizing module.

[0009] Furthermore, the power collection module also includes a voltage regulator tube ZD1, the cathode of the voltage regulator tube ZD1 is electrically connected to the cathode of the diode D2 and the input end of the voltage regulator module respectively, and the anode of the voltage regulator tube ZD1 is electrically connected to the anode of the diode D1 and the ground end of the voltage regulator module respectively.

[0010] Furthermore, the power collection module also includes a capacitor C1, one end of the capacitor C1 is electrically connected to the cathode of the diode D1 and the input end of the voltage stabilizing module respectively, and the other end of the capacitor C1 is electrically connected to the anode of the diode D1 and the ground end of the voltage stabilizing module respectively.

[0011] Furthermore, the electric energy collection module further includes a capacitor C4, and the anode of the diode D1 is electrically connected to the other end of the current transformer T1 through the capacitor C4.

[0012] Furthermore, the voltage monitoring module includes a chip U3, an input terminal of the chip U3 is connected to a power supply, an output terminal of the chip U3 is electrically connected to a control terminal of the voltage stabilizing module, and a ground terminal of the chip U3 is grounded.

[0013] Furthermore, the voltage monitoring module further includes a diode D3, an anode of the diode D3 is electrically connected to the output end of the chip U3, and a cathode of the diode D3 is electrically connected to the control end of the voltage stabilization module.

[0014] Furthermore, the voltage stabilizing module includes a voltage stabilizing chip U1, the input end of the voltage stabilizing chip U1 is electrically connected to the power collection module, the control end of the voltage stabilizing chip U1 is electrically connected to the voltage monitoring module, and the output end of the voltage stabilizing chip U1 is electrically connected to the microcontroller module.

[0015] Furthermore, the temperature sensing module includes a thermistor R2, one end of the thermistor R2 is electrically connected to the microcontroller module, and the other end of the thermistor R2 is grounded.

[0016] Furthermore, the microcontroller module includes a chip U2, the model of the chip U2 is CC1310, the power supply end of the chip U2 is electrically connected to the voltage regulator module, and the digital input and output end of the chip U2 is electrically connected to the temperature sensor module.

[0017] The beneficial effects of the present invention are:

[0018] This solution sets up an electric energy acquisition module, a voltage monitoring module, a voltage stabilizing module, a microcontroller module, a temperature sensing module and a radio frequency module. The electric energy acquisition module is electrically connected to the input end of the voltage stabilizing module, the voltage monitoring module is electrically connected to the control end of the voltage stabilizing module, and the microcontroller module is electrically connected to the output end of the voltage stabilizing module, the temperature sensing module and the radio frequency module respectively. The electric energy acquisition module is used to collect electric energy from the AC bus to provide a steady supply of power; the voltage monitoring module is used to monitor the output voltage of the electric energy acquisition module in real time to ensure the power supply stability and safety of the system; the voltage stabilizing module is used to provide stable voltage; the microcontroller module is responsible for data acquisition and processing; the microcontroller module is electrically connected to the radio frequency module to realize wireless communication; the temperature sensing module is used to monitor changes in ambient temperature; this solution achieves efficient and reliable environmental monitoring through the cooperation between the electric energy acquisition module, the voltage monitoring module, the voltage stabilizing module, the microcontroller module and the temperature sensing module, thereby improving the safety and work efficiency of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a connection block diagram of the passive wireless temperature measurement circuit of the present utility model;

[0020] Figure 2 This is a circuit diagram of the passive wireless temperature measurement circuit of the present utility model;

[0021] Description of labels:

[0022] 1. Power collection module; 2. Voltage monitoring module; 3. Voltage stabilization module; 4. Microcontroller module; 5. Temperature sensor module; 6. Radio frequency module. DETAILED DESCRIPTION

[0023] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following description is given in conjunction with the embodiments and the accompanying drawings.

[0024] Please refer to Figure 1 , the technical solution adopted by this utility model is:

[0025] A passive wireless temperature measurement circuit includes an electric energy acquisition module, a voltage monitoring module, a voltage stabilization module, a microcontroller module, a temperature sensing module and a radio frequency module. The electric energy acquisition module is electrically connected to the input end of the voltage stabilization module, the voltage monitoring module is electrically connected to the control end of the voltage stabilization module, and the microcontroller module is electrically connected to the output end of the voltage stabilization module, the temperature sensing module and the radio frequency module respectively.

[0026] From the above description, it can be seen that the beneficial effects of the present invention are:

[0027] This solution sets up an electric energy acquisition module, a voltage monitoring module, a voltage stabilizing module, a microcontroller module, a temperature sensing module and a radio frequency module. The electric energy acquisition module is electrically connected to the input end of the voltage stabilizing module, the voltage monitoring module is electrically connected to the control end of the voltage stabilizing module, and the microcontroller module is electrically connected to the output end of the voltage stabilizing module, the temperature sensing module and the radio frequency module respectively. The electric energy acquisition module is used to collect electric energy from the AC bus to provide a steady supply of power; the voltage monitoring module is used to monitor the output voltage of the electric energy acquisition module in real time to ensure the power supply stability and safety of the system; the voltage stabilizing module is used to provide stable voltage; the microcontroller module is responsible for data acquisition and processing; the microcontroller module is electrically connected to the radio frequency module to realize wireless communication; the temperature sensing module is used to monitor changes in ambient temperature; this solution achieves efficient and reliable environmental monitoring through the cooperation between the electric energy acquisition module, the voltage monitoring module, the voltage stabilizing module, the microcontroller module and the temperature sensing module, thereby improving the safety and work efficiency of the equipment.

[0028] Furthermore, the electric energy collection module includes a current transformer T1, a diode D1 and a diode D2, one end of the current transformer T1 is electrically connected to the cathode of the diode D1 and the anode of the diode D2, respectively, the other end of the current transformer T1 is electrically connected to the anode of the diode D1 and the ground end of the voltage stabilizing module, and the cathode of the diode D2 is electrically connected to the input end of the voltage stabilizing module.

[0029] As can be seen from the above description, current transformer T1 is a device used to collect AC current. In this device application, it obtains electromagnetic energy from the AC bus and outputs an AC signal. This signal itself cannot be used directly as a DC power supply and therefore requires correction and subsequent processing. The half-bridge adjustment circuit is composed of two diodes (diode D1 and diode D2). Its function is to convert the AC signal into DC power. In half-bridge adjustment, the positive half-cycle of the AC signal is turned on by diode D1, and the negative half-cycle is turned on by diode D2. In this way, the alternating positive and negative AC signal is adjusted into a unidirectional pulsating DC current. After adjustment, it requires fewer components, which can reduce the PCBA area of ​​the device.

[0030] Furthermore, the power collection module also includes a voltage regulator tube ZD1, the cathode of the voltage regulator tube ZD1 is electrically connected to the cathode of the diode D2 and the input end of the voltage regulator module respectively, and the anode of the voltage regulator tube ZD1 is electrically connected to the anode of the diode D1 and the ground end of the voltage regulator module respectively.

[0031] As can be seen from the above description, the adjusted voltage will fluctuate with changes in the input voltage. Therefore, a voltage regulator diode ZD1 is connected to the output of the adjustment circuit to protect the circuit. It shuns the current (clamps the voltage) when the voltage exceeds the set value, thus preventing the adjusted voltage from being too high. The voltage regulator diode ZD1 ensures that the output voltage remains within a safe range, preventing damage to capacitors or other components due to overvoltage.

[0032] Furthermore, the power collection module also includes a capacitor C1, one end of the capacitor C1 is electrically connected to the cathode of the diode D1 and the input end of the voltage stabilizing module respectively, and the other end of the capacitor C1 is electrically connected to the anode of the diode D1 and the ground end of the voltage stabilizing module respectively.

[0033] From the above description, we can see that although the pulsed DC voltage output by the half-bridge adjustment is a unidirectional current, the voltage is not stable and has obvious fluctuations. In order to provide stable DC power, it is necessary to add a filter capacitor after correction. Capacitor C1 can store charge and release energy when the voltage drops, smoothing the adjusted voltage waveform and making it more stable.

[0034] Furthermore, the electric energy collection module further includes a capacitor C4, and the anode of the diode D1 is electrically connected to the other end of the current transformer T1 through the capacitor C4.

[0035] Furthermore, the voltage monitoring module includes a chip U3, an input terminal of the chip U3 is connected to a power supply, an output terminal of the chip U3 is electrically connected to a control terminal of the voltage stabilizing module, and a ground terminal of the chip U3 is grounded.

[0036] From the above description, it can be seen that the main task of the voltage monitoring module is to monitor the output voltage VDD of the power acquisition module in real time to ensure the power supply stability and safety of the system; the passive power supply system relies on an external energy source to generate electricity, but during the system startup or operation, the VDD voltage may be unstable; the voltage monitoring module detects the VDD voltage of the power acquisition module to ensure that it reaches a certain set threshold before starting subsequent modules to prevent abnormal operation under low voltage conditions; when the VDD voltage rises and reaches the set threshold voltage, the chip U3 outputs a high-level signal to control the voltage stabilization module, which can determine whether the system has instantaneous power reserves through the preset threshold to avoid the system starting in a low-voltage state, thereby ensuring the stability of the circuit; when the chip U3 detects that the VDD voltage has reached the set threshold, its output switches to a high-level signal, triggering the start of the voltage stabilization module.

[0037] Furthermore, the voltage monitoring module further includes a diode D3, an anode of the diode D3 is electrically connected to the output end of the chip U3, and a cathode of the diode D3 is electrically connected to the control end of the voltage stabilization module.

[0038] From the above description, it can be seen that the diode D3 is introduced into the circuit to achieve the unidirectional current conduction function and avoid the adverse consequences of chip U3 being damaged by current backflow; the diode D3 needs to have appropriate reverse voltage and current carrying capacity to ensure that the reverse current can be effectively suppressed in any circuit state to prevent load backflow from damaging the circuit.

[0039] Furthermore, the voltage stabilizing module includes a voltage stabilizing chip U1, the input end of the voltage stabilizing chip U1 is electrically connected to the power collection module, the control end of the voltage stabilizing chip U1 is electrically connected to the voltage monitoring module, and the output end of the voltage stabilizing chip U1 is electrically connected to the microcontroller module.

[0040] From the above description, it can be seen that the control end of the voltage regulator chip U1 is used to control the switching state of the voltage regulator chip U1. In this solution, the control end of the voltage regulator chip U1 is connected to the voltage monitoring module to ensure that the voltage regulator chip U1 will start working only when the voltage monitoring module detects sufficient input voltage; when the input voltage reaches the preset threshold voltage, the voltage monitoring module will output a high-level signal to activate the voltage regulator chip U1 and start working; this can avoid the situation where the voltage regulator chip U1 is turned on and cannot provide a stable output when the input voltage is insufficient, thereby affecting the normal operation of the downstream circuit; when the input voltage is insufficient, the voltage monitoring module will not output a high-level signal, and the voltage regulator chip U1 will remain in the off state to prevent the input voltage from affecting the microcontroller unit and other modules; as the input voltage rises, when the voltage reaches the preset threshold, the voltage monitoring module outputs a high-level signal. After the control end of the voltage regulator chip U1 receives the signal, the voltage regulator chip U1 is enabled and starts to provide a stable output voltage.

[0041] Furthermore, the temperature sensing module includes a thermistor R2, one end of the thermistor R2 is electrically connected to the microcontroller module, and the other end of the thermistor R2 is grounded.

[0042] Furthermore, the microcontroller module includes a chip U2, the model of the chip U2 is CC1310, the power supply end of the chip U2 is electrically connected to the voltage regulator module, and the digital input and output end of the chip U2 is electrically connected to the temperature sensor module.

[0043] Please refer to Figure 1 and Figure 2 As shown, the first embodiment of the present utility model is:

[0044] Please refer to Figure 1A passive wireless temperature measurement circuit includes an energy acquisition module 1, a voltage monitoring module 2, a voltage stabilizing module 3, a microcontroller module 4, a temperature sensing module 5 and a radio frequency module 6. The energy acquisition module 1 is electrically connected to the input end of the voltage stabilizing module 3, the voltage monitoring module 2 is electrically connected to the control end of the voltage stabilizing module 3, and the microcontroller module 4 is electrically connected to the output end of the voltage stabilizing module 3, the temperature sensing module 5 and the radio frequency module 6 respectively.

[0045] Please refer to Figure 2 The electric energy collection module 1 includes a current transformer T1, a diode D1 and a diode D2. One end of the current transformer T1 is electrically connected to the cathode of the diode D1 and the anode of the diode D2, respectively. The other end of the current transformer T1 is electrically connected to the anode of the diode D1 and the ground end of the voltage stabilizing module 3, respectively. The cathode of the diode D2 is electrically connected to the input end of the voltage stabilizing module 3.

[0046] Please refer to Figure 2 The electric energy collection module 1 also includes a voltage regulator tube ZD1, the cathode of the voltage regulator tube ZD1 is electrically connected to the cathode of the diode D2 and the input end of the voltage regulator module 3, and the anode of the voltage regulator tube ZD1 is electrically connected to the anode of the diode D1 and the ground end of the voltage regulator module 3.

[0047] Please refer to Figure 2 The power collection module 1 also includes a capacitor C1, one end of the capacitor C1 is electrically connected to the cathode of the diode D1 and the input end of the voltage stabilizing module 3, and the other end of the capacitor C1 is electrically connected to the anode of the diode D1 and the ground end of the voltage stabilizing module 3.

[0048] Please refer to Figure 2 The electric energy collection module 1 further includes a capacitor C4, and the anode of the diode D1 is electrically connected to the other end of the current transformer T1 through the capacitor C4.

[0049] Please refer to Figure 2 The voltage monitoring module 2 includes a chip U3, an input end of the chip U3 is connected to a power supply, an output end of the chip U3 is electrically connected to a control end of the voltage stabilizing module 3, and a ground end of the chip U3 is grounded.

[0050] Please refer to Figure 2 The voltage monitoring module 2 further includes a diode D3 , an anode of the diode D3 is electrically connected to the output end of the chip U3 , and a cathode of the diode D3 is electrically connected to the control end of the voltage stabilizing module 3 .

[0051] Please refer to Figure 2The voltage stabilizing module 3 includes a voltage stabilizing chip U1, the input end of the voltage stabilizing chip U1 is electrically connected to the power collection module 1, the control end of the voltage stabilizing chip U1 is electrically connected to the voltage monitoring module 2, and the output end of the voltage stabilizing chip U1 is electrically connected to the microcontroller module 4.

[0052] Please refer to Figure 2 The temperature sensing module 5 includes a thermistor R2 , one end of the thermistor R2 is electrically connected to the microcontroller module 4 , and the other end of the thermistor R2 is grounded.

[0053] The temperature sensing module 5 also includes a resistor R1. For details on the connection between the resistor R1 and other components, please refer to Figure 2 .

[0054] Please refer to Figure 2 The microcontrol module 4 includes a chip U2, the model of the chip U2 is CC1310, the power supply end of the chip U2 is electrically connected to the voltage regulator module 3, and the digital input and output end of the chip U2 is electrically connected to the temperature sensor module 5.

[0055] The microcontroller module 4 also includes a capacitor C3, an inductor L1 and an inductor L2. For the specific connection relationship between the components, please refer to Figure 2 ; Capacitor C1 is a coupling capacitor that can isolate the DC component and allow the AC RF signal to pass through; Inductor L1 is a bypass inductor used to reduce power supply noise and ensure stable operation of the RF circuit; Inductor L2 is an RF inductor used for filtering, tuning and impedance matching.

[0056] The radio frequency module 6 is mainly composed of a high-efficiency radio frequency transceiver (RF Transceiver), which contains multiple components, as follows:

[0057] (1) Frequency Synthesizer: The frequency synthesizer is the core component used to generate different frequency signals required for RF signals. It uses phase-locked loop (PLL) technology to generate the required frequency, control the signal transmission frequency, and ensure the stability and accuracy of the transmitted signal.

[0058] (2) Power amplifier (PA): In transmit mode, chip U2 uses a power amplifier to amplify the low-power RF signal from the baseband signal to the required output power level so that the signal can be transmitted over long distances.

[0059] (3) Low Noise Amplifier (LNA): In the receiving mode, the LNA is used to receive the RF signal from the antenna and amplify it to ensure that the received signal can be correctly interpreted by the subsequent processing unit (such as the demodulator). The low noise characteristics of the LNA are crucial to improving the receiving sensitivity.

[0060] The working principle of the above passive wireless temperature measurement circuit is:

[0061] Current transformer T1 is a device used to collect AC current. In this device, it extracts electromagnetic energy from the AC bus and outputs an AC signal. This signal itself cannot be used directly as a DC power source and therefore requires correction and subsequent processing. A half-bridge regulation circuit, consisting of two diodes (diode D1 and diode D2), converts the AC signal into DC. In half-bridge regulation, diode D1 conducts during the positive half-cycle of the AC signal, while diode D2 conducts during the negative half-cycle. This converts the alternating positive and negative AC signal into a unidirectional, pulsating DC current. This regulation requires fewer components, reducing the device's PCBA size. The rated current of the two diodes must be able to withstand the current output by current transformer T1 to ensure they are not damaged under maximum load. Because the diodes experience high reverse voltage when in reverse, their withstand voltage must be high enough to prevent breakdown under reverse bias. Voltage fluctuations are common in power grids, so the withstand voltage should have sufficient margin. The regulated voltage will change with the input voltage. The output voltage fluctuates due to changes in the input voltage. Therefore, a voltage regulator diode ZD1 is connected to the output end of the adjustment circuit to protect the circuit. It shunts the current (clamps the voltage) when the voltage exceeds the set value, thereby preventing the corrected voltage from being too high. The voltage regulator diode ZD1 ensures that the output voltage remains within a safe range, preventing damage to capacitors or other components due to overvoltage. Although the pulsed DC voltage output by the half-bridge adjustment is a unidirectional current, the voltage is not stable and has significant fluctuations. To provide stable DC power, a filter capacitor is added after the correction. Capacitor C1 can store charge and release energy when the voltage drops, smoothing the adjusted voltage waveform and making it more stable. The rated voltage of capacitor C1 must be higher than the adjusted voltage, otherwise it will easily be damaged. In addition, the capacitance of capacitor C1 determines the suppression effect. Increasing the capacitance can better smooth fluctuations, but it will slow the circuit response. This needs to be balanced according to actual needs. Through the reasonable configuration and design of these components, the power collection module 1 can collect power from the AC bus and provide a stable DC power supply to the device after adjustment and voltage stabilization.

[0062] The main task of voltage monitoring module 2 is to monitor the output voltage (VDD) of the power acquisition module in real time to ensure the system's power supply stability and safety. Passive power supply systems rely on external energy sources to generate power, but the VDD voltage may be unstable during system startup or operation. Voltage monitoring module 2 detects the VDD voltage of power acquisition module 1 and ensures it reaches a certain threshold before starting subsequent modules to prevent abnormal operation under low-voltage conditions. Chip U3 is a voltage monitoring chip specifically designed to detect voltage levels. When the VDD voltage rises and reaches the set threshold voltage, chip U3 outputs a high-level signal to control voltage regulator chip U1. The preset threshold can be used to determine whether the system has instantaneous power reserves, preventing the system from starting under low voltage conditions and thus ensuring circuit stability. When chip U3 detects that VDD has reached the set threshold, its output switches to a high-level signal, triggering the startup of voltage regulator chip U1. This complete process effectively manages power distribution, ensuring that each module operates at a stable voltage and preventing system failures caused by insufficient voltage. In a passive power supply system, capacitor C1 not only plays a supporting role but also serves as a short-term energy storage function. It stores energy after correction and provides power to the load when needed. However, without voltage monitoring, the energy on capacitor C1 will gradually deplete as the load continues to be powered. If the load requires an instantaneous increase in current (for example, when wireless transmission or micro-unit control is activated), and capacitor C1 does not have enough energy stored, the supply voltage may drop, affecting normal system operation. By adding voltage monitoring module 2, chip U3 can ensure that the energy stored on capacitor C1 reaches a sufficient level before critical operations (such as temperature acquisition and signal transmission) begin. This avoids starting chip U3 when the capacitor energy is insufficient. Only when there is sufficient energy on capacitor C1 will subsequent operating modules be activated, preventing voltage fluctuations and power supply instability. In actual operation, the system power supply stability will be tested, especially when the system load requires a momentary high current. For example, starting the wireless transmission module consumes a large amount of power. If the energy stored on capacitor C1 is insufficient at this time, the supply voltage will drop, which will lead to unstable power supply to the micro-control unit and even reset or operation errors. Therefore, voltage monitoring module 2 ensures sufficient energy in capacitor C1 by controlling the output of chip U3 to avoid these problems. Diode D3 is introduced into the circuit to achieve unidirectional current conduction, preventing the adverse consequences of current backflow and damage to chip U3. Diode D3 needs to have appropriate reverse voltage and current carrying capacity to ensure that it can effectively suppress reverse current in all circuit conditions and prevent load backflow from damaging the circuit.

[0063] The input end of the voltage regulator chip U1 is connected to the power supply provided by the power collection module 1, and the voltage of the power supply may vary with the input voltage; therefore, the input voltage range of the voltage regulator chip U1 needs to be wide enough to adapt to different input voltage conditions; the voltage regulator chip U1 needs to provide sufficient current for the microcontroller module 4 and other modules; the microcontroller module 4 usually requires a stable power supply voltage and an appropriate working current, therefore, the output current capacity of the voltage regulator chip U1 must be large enough to meet the working requirements of the entire system. The input and output ends of the voltage regulator chip U1 usually need to be configured with appropriate capacitors to smooth voltage fluctuations and avoid rapid changes in input voltage affecting the stability of the output voltage; the control end of the voltage regulator chip U1 is used to control the switching state of the voltage regulator chip U1; in this solution, the control end of the voltage regulator chip U1 is connected to the voltage monitoring module 2 to ensure that the voltage regulator chip U1 will start working only when the voltage monitoring module 2 detects sufficient input voltage; when the input voltage reaches the preset threshold voltage, the voltage monitoring module 2 will output a high-level signal to activate the voltage regulator chip U1 and start working; this can avoid the voltage regulator chip U1 from working when the input voltage is insufficient. When chip U1 is turned on, it cannot provide a stable output, thus affecting the normal operation of downstream circuits. When the input voltage is insufficient, the voltage monitoring module 2 will not output a high-level signal, and the voltage regulator chip U1 will remain in a closed state to prevent the input voltage from affecting the microcontroller module 4 and other modules. As the input voltage rises, when the voltage reaches a preset threshold, the voltage monitoring module 2 outputs a high-level signal. After the control terminal of the voltage regulator chip U1 receives this signal, the voltage regulator chip U1 is enabled and begins to provide a stable output voltage. The output voltage is stably output by the voltage regulator chip U1 and provided to the microcontroller module 4 and other modules to ensure that they operate at a stable voltage. In passive power supply systems, the energy harvesting process is not always linear and stable, and the input voltage can fluctuate at any time. Therefore, the supply voltage of the voltage regulator chip U1 and the voltage monitoring module 2 is very important. When energy harvesting is insufficient, the system does not perform any high-power operations, preventing unstable power supply from affecting the normal operation of the equipment. It can also maximize the use of limited power reserves, improve the overall efficiency of the system, and reduce failures.

[0064] Microcontroller module 4 utilizes a low-power microcontroller (CC1310) designed for efficient IoT applications. It features a rich I / O interface and built-in ADC, making it suitable for sensor data acquisition and wireless communication. Microcontroller module 4 is responsible for the overall device control logic, coordinating the operating status of each module to ensure system stability and reliability. It integrates a timer function that supports periodic sensor activation for data acquisition, optimizing energy usage. The built-in ADC directly reads the temperature sensor's analog signal and converts it into a digital signal to ensure data accuracy. Sampling frequency and analog algorithms are used to eliminate noise and improve data quality. Wireless data transmission is possible, transmitting collected temperature data to the receiving end. An efficient data packet structure is designed to minimize information defects and ensure transmission reliability. To achieve a low-power sleep mode, the microcontroller enters a deep sleep state when inactive, significantly reducing power consumption. A wake-up mechanism is designed to automatically activate the microcontroller when needed for data acquisition and communication, extending the device's operating life. Firmware programming is performed using the Keil IDE, which supports a rich library and middleware suite to simplify the development process. An interrupt service routine is written to handle external events and sensor data readings, ensuring real-time and responsiveness.

[0065] To ensure effective signal transmission, this solution utilizes a 433MHz frequency, which offers excellent consistency and a suitable transmission distance, making it suitable for industrial environments and outdoor applications. Temperature data collected by the microcontroller module 4 is wirelessly transmitted to the terminal monitoring system for real-time monitoring and data logging. Efficient modulation and demodulation technologies ensure data stability and interference resistance during transmission. The 433MHz frequency was chosen based on the wireless signal's transmission distance, effectively shielding against walls and other obstacles, making it adaptable to complex environments. This frequency also complies with wireless communication regulations in various countries, ensuring compliance. Based on the selected communication protocol, the corresponding protocol stack is implemented to handle data resources, transmission, and reception. A spring antenna is selected to enhance signal transmission and reception capabilities. Its resilience and adjustability allow for optimized length and position. The antenna's mounting position is carefully designed to ensure optimal signal coverage and minimize interference. The radio frequency module 6 has built-in data storage, temporarily storing data in the event of a signal failure, ensuring continued transmission when conditions are restored. A retransmission mechanism is implemented to address signal loss and data errors, ensuring data integrity.

[0066] This solution selects a bead-shaped temperature-measuring NTC thermistor as the temperature sensor. The value of the NTC (negative temperature coefficient) thermistor decreases as the temperature increases. The bead-shaped NTC thermistor is characterized by fast response time and high measurement accuracy, and is suitable for scenarios where rapid acquisition of temperature changes is required. The output end of the NTC thermistor R2 is connected to the ADC (analog-to-digital converter) input end of the microcontroller module 4 through a voltage divider circuit. The ADC can convert the analog voltage signal generated by the thermistor R2 into a digital signal. In order to ensure the accuracy of the collected data, the design of the voltage divider circuit selects a suitable voltage divider resistance value based on the temperature characteristics of the NTC thermistor and the system's power supply voltage to ensure that the ADC input voltage is within the appropriate range and avoid signal distortion. The microcontroller module 4 collects the voltage signal from the NTC thermistor in real time through the ADC interface, which is usually a periodic acquisition process.

[0067] To ensure the continuity and real-time nature of data collection, the microcontroller module 4 uses a timed interrupt method to read data at set time intervals. By cyclically reading the data from the NTC thermistor, the system can ensure that it can continuously monitor changes in ambient temperature. Since the resistance value of the NTC thermistor changes with temperature, its output voltage value will also change. In order to obtain a specific temperature value, the voltage must be converted to the corresponding temperature using the known NTC resistance temperature curve. The Stern formula (Steinhart-Hart formula) corresponding to the NTC thermistor can convert the thermistor voltage into the actual temperature value. The general form of this formula is as follows:

[0068]

[0069] Where T is the temperature (in Kelvin), R is the resistance of the thermistor (in ohms), R0 is the resistance of the NTC thermistor at a reference temperature (in ohms), and A, B, and C are the characteristic coefficients of the NTC thermistor, determined through experimental measurements. Through this conversion method, the system can convert the voltage value collected in real time into accurate temperature data.

[0070] In practical applications, data collected by temperature sensors is often subject to interference from various external factors, such as electromagnetic interference and sensor noise. To address this issue, this solution introduces the Kalman filter algorithm, a commonly used linear algorithm that uses mathematical models to predict and modify measurement values, reducing noise interference. The Kalman filter algorithm predicts the current temperature value and takes a weighted average of the current measurement data to obtain a more accurate estimate. It dynamically adjusts the weighting between high-precision prediction and high-precision measurement to achieve a more accurate estimate and gradually optimize the temperature data. The algorithm primarily consists of two steps: predicting the current temperature value based on the previous data and its changing trend; comparing the predicted value with the current actual measurement value, calculating the residual, updating the estimate based on the residual, and modifying the corresponding data. The Kalman filter significantly reduces random noise in temperature data, enabling the system to obtain smoother and more accurate temperature data, thereby improving overall system reliability.

[0071] Since the system uses NTC thermistors and the microcontroller module 4 for data acquisition, the system has low power consumption. In order to further extend the service life of the device, this solution has designed a low-power mode. When the temperature data does not exceed the normal range, the microcontroller module 4 can enter a deep sleep mode and will only wake up when a scheduled task or a threshold is exceeded to collect and process data. Through reasonable planning of the sampling cycle, the system can reduce power consumption while ensuring real-time data. For example, in scenarios where the temperature changes slowly, the sampling frequency is reduced (such as once every 10 minutes), and in the case of a sharp increase in temperature, the sampling frequency is increased (such as once every 10 seconds). This adjustment mechanism can effectively balance the dynamics and performance of the system.

[0072] The circuit designed in this solution can be widely used in many fields. The following are several specific application scenarios:

[0073] 1. Power system: Real-time monitoring of the temperature inside the substation to ensure that the equipment operates within a safe range and prevent equipment failure caused by overheating; monitor the operating environment of power generation equipment and transformers to ensure efficient and safe operation of the equipment.

[0074] 2. Rail transit power supply system: In the rail transit power supply system, monitor the temperature status of the power supply equipment to ensure the stability and reliability of the power supply system.

[0075] 3. Industrial electrical equipment: Real-time temperature monitoring in industrial computer rooms ensures that the equipment operates in a suitable environment and prevents equipment damage caused by environmental problems.

[0076] 4. New energy power generation and energy storage system: Monitor the temperature of photovoltaic modules and inverters to ensure that the equipment operates under optimal conditions and improve power generation efficiency.

[0077] 5. Energy storage system: monitors the environmental conditions of the battery pack to prevent safety hazards caused by excessive temperature.

[0078] Through the above specific application scenarios, this passive wireless temperature measurement circuit can help users achieve efficient and reliable environmental monitoring and improve the safety and work efficiency of equipment.

[0079] To sum up, the utility model provides a passive wireless temperature measurement circuit, which is equipped with an electric energy acquisition module, a voltage monitoring module, a voltage stabilizing module, a microcontroller module, a temperature sensing module and a radio frequency module. The electric energy acquisition module is electrically connected to the input end of the voltage stabilizing module, the voltage monitoring module is electrically connected to the control end of the voltage stabilizing module, and the microcontroller module is electrically connected to the output end of the voltage stabilizing module, the temperature sensing module and the radio frequency module respectively. The electric energy acquisition module is used to collect electric energy from the AC bus to provide a steady supply of power; the voltage monitoring module is used to monitor the output voltage of the electric energy acquisition module in real time to ensure the power supply stability and safety of the system; the voltage stabilizing module is used to provide a stable voltage; the microcontroller module is responsible for data acquisition and processing; the microcontroller module is electrically connected to the radio frequency module to realize wireless communication; the temperature sensing module is used to monitor changes in ambient temperature; this scheme realizes efficient and reliable environmental monitoring through the cooperation between the electric energy acquisition module, the voltage monitoring module, the voltage stabilizing module, the microcontroller module and the temperature sensing module, thereby improving the safety and work efficiency of the equipment.

[0080] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent transformations made using the contents of the description and drawings of the present invention, or directly or indirectly applied in the relevant technical field, are also included in the patent protection scope of the present invention.

Claims

1. A passive wireless temperature measurement circuit, characterized in that: It includes an electric energy acquisition module, a voltage monitoring module, a voltage stabilization module, a microcontroller module, a temperature sensing module and a radio frequency module. The electric energy acquisition module is electrically connected to the input end of the voltage stabilization module, the voltage monitoring module is electrically connected to the control end of the voltage stabilization module, and the microcontroller module is electrically connected to the output end of the voltage stabilization module, the temperature sensing module and the radio frequency module respectively.

2. The passive wireless temperature measurement circuit according to claim 1, characterized in that: The electric energy collection module includes a current transformer T1, a diode D1 and a diode D2. One end of the current transformer T1 is electrically connected to the cathode of the diode D1 and the anode of the diode D2, respectively. The other end of the current transformer T1 is electrically connected to the anode of the diode D1 and the ground end of the voltage stabilizing module, respectively. The cathode of the diode D2 is electrically connected to the input end of the voltage stabilizing module.

3. The passive wireless temperature measurement circuit according to claim 2, characterized in that: The power collection module further includes a voltage regulator tube ZD1, the cathode of which is electrically connected to the cathode of the diode D2 and the input end of the voltage regulator module, and the anode of which is electrically connected to the anode of the diode D1 and the ground end of the voltage regulator module.

4. The passive wireless temperature measurement circuit according to claim 2, characterized in that: The power collection module further includes a capacitor C1, one end of which is electrically connected to the cathode of the diode D1 and the input end of the voltage stabilizing module, and the other end of which is electrically connected to the anode of the diode D1 and the ground end of the voltage stabilizing module.

5. The passive wireless temperature measurement circuit according to claim 2, characterized in that: The electric energy collection module further includes a capacitor C4 , and the anode of the diode D1 is electrically connected to the other end of the current transformer T1 via the capacitor C4 .

6. The passive wireless temperature measurement circuit according to claim 1, characterized in that: The voltage monitoring module includes a chip U3 , an input terminal of the chip U3 is connected to a power supply, an output terminal of the chip U3 is electrically connected to a control terminal of the voltage stabilizing module, and a ground terminal of the chip U3 is grounded.

7. The passive wireless temperature measurement circuit according to claim 6, characterized in that: The voltage monitoring module further includes a diode D3 , an anode of the diode D3 is electrically connected to the output end of the chip U3 , and a cathode of the diode D3 is electrically connected to the control end of the voltage stabilizing module.

8. The passive wireless temperature measurement circuit according to claim 1, characterized in that: The voltage stabilizing module includes a voltage stabilizing chip U1, the input end of the voltage stabilizing chip U1 is electrically connected to the power collection module, the control end of the voltage stabilizing chip U1 is electrically connected to the voltage monitoring module, and the output end of the voltage stabilizing chip U1 is electrically connected to the microcontroller module.

9. The passive wireless temperature measurement circuit according to claim 1, characterized in that: The temperature sensing module includes a thermistor R2 , one end of the thermistor R2 is electrically connected to the microcontroller module, and the other end of the thermistor R2 is grounded.

10. The passive wireless temperature measurement circuit according to claim 1, characterized in that: The microcontroller module includes a chip U2, the model of the chip U2 is CC1310, the power supply end of the chip U2 is electrically connected to the voltage stabilizing module, and the digital input and output end of the chip U2 is electrically connected to the temperature sensing module.

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