An adaptive ct sensor

Abstract

The utility model relates to power monitoring technical field especially, it relates to a kind of self-adapting CT sensor, the utility model includes CT sensor, energy collection circuit, power management unit, microcontroller unit, the input end of energy collection circuit is connected to the secondary coil of CT sensor;Microcontroller unit includes microcontroller, microcontroller built-in energy management and adaptive algorithm;Energy management and adaptive algorithm can adaptively adjust working mode, adjustment working mode includes adjusting the sampling frequency of temperature data and current data, adjustment the frequency of wireless data sending, the utility model can integrate temperature measurement function, installation and maintenance are relatively simple, and have certain anti-electromagnetic interference ability;Without additionally setting power supply;With adaptability, according to the power adaptive adjustment working mode, under the premise of guaranteeing basic monitoring function, maximum limit uses energy, improves the reliability and stability of system under different working conditions.

Description

Technical Field

[0001] This utility model relates to the field of power monitoring technology, and in particular to an adaptive CT sensor. Background Technology

[0002] Current transformer (CT) sensors are widely used current measuring elements in power systems and industrial control. Their basic principle is to use electromagnetic induction to proportionally convert a large measured current into a small, easily measurable current or voltage signal. Traditional CT sensors primarily measure current. In practical applications, such as in high-voltage switchgear, busbar connection points, and cable joints, in addition to monitoring current, it is also necessary to monitor the temperature of these critical components to prevent equipment failures or safety accidents caused by overheating.

[0003] To this end, utility model patent CN202034229U discloses an electronic current transformer with a temperature measuring device, relating to electronic current transformers. It provides an electronic current transformer with a temperature measuring device that can monitor the temperature of the electronic current transformer in real time, integrates the temperature measuring device with the electronic current transformer, and maintains the structure and function of the electronic current transformer. It includes an electronic current transformer, in which a temperature sensor is integrated, and the temperature sensor has an optical temperature measuring element and a signal transmission optical fiber. The optical temperature measuring element is embedded in the electronic current transformer, and the signal transmission optical fiber is located within the electronic current transformer.

[0004] However, the electronic current transformer with temperature measurement device in this patent has a high system cost and relatively complex installation and maintenance for temperature measurement and optical temperature measurement. It usually needs to be deployed independently and is difficult to integrate tightly with current measurement and achieve self-powering. In addition, the device does not have adaptive adjustment function and cannot make full use of external energy to achieve the function, which makes the system lack reliability and stability under different operating conditions.

[0005] Therefore, it is necessary to further improve an adaptive CT sensor. Utility Model Content

[0006] The technical problem to be solved by this utility model is to overcome the existing defects and provide an adaptive CT sensor that integrates temperature measurement function, has low cost, is relatively easy to install and maintain, does not require a separate power supply, and has adaptive properties, thus effectively solving the problems in the background art.

[0007] To achieve the above objectives, this utility model provides the following technical solution: an adaptive CT sensor, comprising a CT sensor, an energy harvesting circuit, a power management unit, and a microcontroller unit;

[0008] The energy harvesting circuit has its input terminal connected to the secondary coil of the CT sensor;

[0009] The microcontroller unit includes a microcontroller; the output of the energy harvesting circuit is connected to the input of the power management unit; the output of the power management unit is connected to the microcontroller unit; the microcontroller unit is connected to a temperature sensor; and the microcontroller is connected to a wireless communication module.

[0010] The temperature sensor uses an integrated temperature sensor chip with digital output; a bypass capacitor is placed close to the chip at the VCC pin of the temperature sensor.

[0011] The temperature sensor is installed near the CT core, the secondary coil, or near the primary conductor.

[0012] Preferably, the energy harvesting circuit includes a rectifier circuit and an energy storage element circuit.

[0013] Preferably, the rectifier circuit includes a secondary coil of the CT sensor, a rectifier bridge D1, and a capacitor C1; the two ends of the secondary coil of the CT sensor are connected to the two AC input terminals of the rectifier bridge D1, and the positive output terminal and the negative output terminal of the rectifier bridge D1 are connected to the positive and negative terminals of the capacitor C1, respectively.

[0014] Preferably, the energy storage element circuit includes a capacitor C2 and a diode U2; the positive and negative terminals of capacitor C2 are respectively connected to the positive and negative terminals of capacitor C1, and a diode U2 is connected in series between the positive terminals of capacitor C2 and capacitor C1.

[0015] The working principle and application principle of this utility model are as follows:

[0016] The CT sensor is the basic structure, with a central hole for the conductor through which the current to be measured (primary side) passes. When an alternating current flows through the primary conductor, according to the law of electromagnetic induction, a secondary current or voltage, reduced according to the turns ratio, will be induced in the secondary coil wound on the magnetic core.

[0017] The output of the secondary coil of this invention is used not only for current measurement but also as an energy source.

[0018] The microcontroller unit includes a microcontroller; the signal output terminal of the temperature sensor is connected to the digital interface of the microcontroller unit.

[0019] The microcontroller is the control core of the entire system. It integrates energy management and adaptive algorithms, signal acquisition and processing modules, wireless communication protocol stack and data processing modules, system scheduling and control modules, and calibration and configuration modules. It is powered by the power management unit and its main tasks include: periodically reading temperature data from the temperature sensor; processing signals from the secondary coil to obtain current values; and executing adaptive logic based on the energy level information obtained from the power management unit.

[0020] Temperature sensors are installed near the CT core, secondary coil, or primary conductor to accurately measure the temperature of hot spots that may be caused by high current or poor contact.

[0021] The wireless communication module employs low-power wireless communication technology to adapt to situations where energy harvesting power is limited. The microcontroller controls the wireless communication module to package the processed current and temperature data and send it out according to a preset protocol.

[0022] The energy harvesting circuit converts the alternating current induced by the secondary coil into pulsating direct current, which is then filtered by the filter capacitor C1. The filtered direct current can be used to charge the energy storage element capacitor C2.

[0023] The power management unit is connected to the output of the energy harvesting circuit. Its core is a high-efficiency voltage regulator that converts the unstable or high voltage on the energy storage element into a stable voltage required for the operation of the microcontroller, temperature sensor and wireless communication module.

[0024] The power management unit also has a voltage monitoring function, which can provide the microcontroller with the current voltage information of the energy storage elements, reflecting the current available energy level.

[0025] The microcontroller periodically reads the voltage V_C2 on the energy storage element through the power management unit, which directly reflects the current available energy level.

[0026] In terms of external power consumption, the microcontroller can be configured with several voltage thresholds to distinguish different operating modes, such as (V_crit, V_low, V_high):

[0027] When energy is sufficient (V_C2 is higher than V_high), set the high-performance mode: collect current and temperature data once per second, and send data once per minute through the wireless communication module.

[0028] When the energy level is moderate (V_C2 is determined to be between V_low and V_high), set the normal mode: reduce the sampling frequency, collect current and temperature data once every 10 seconds, and send data once every 10 minutes through the wireless communication module, or only send data when the data changes by a certain amount.

[0029] When the energy is low (determined by V_C2 being lower than V_low and higher than V_crit), set a low-power mode: only collect current data, or further reduce the sampling and transmission frequency.

[0030] When energy is extremely low (V_C2 is lower than V_crit), set emergency mode: enter deep sleep mode, retain only wake-up detection for extremely low power consumption.

[0031] When the monitored voltage crosses a certain threshold, the state machine transitions, and the system enters a new energy state.

[0032] In terms of the microcontroller's own power consumption, the microcontroller uses an ultra-low power microcontroller such as Renesas RA4L1, and enters different low-power sleep modes between tasks; when the energy is sufficient, the microcontroller uses shallow sleep modes such as WFI, and when the energy is low, it uses deep sleep modes such as STOP or Standby.

[0033] Compared with the prior art, the beneficial effects of this utility model are:

[0034] The adaptive CT sensor of this invention can achieve integrated monitoring of current and temperature at key points without the need for external power supply and signal lines, and transmit the data wirelessly. Its adaptive energy management strategy ensures stable operation of the system and efficient use of energy under different primary current conditions.

[0035] It integrates temperature measurement function, has a low cost, is relatively easy to install and maintain, and has a certain degree of resistance to electromagnetic interference;

[0036] The energy harvesting circuit eliminates the need for an additional power supply, enabling self-powered operation of the components.

[0037] It is adaptive and can adjust the working mode according to the power consumption. While ensuring basic monitoring functions, it maximizes the use of energy and improves the reliability and stability of the system under different operating conditions.

[0038] By monitoring current and temperature in real time, potential overcurrent or overheating hazards can be detected in a timely manner, thereby improving the safety of power equipment operation. Attached Figure Description

[0039] Figure 1 This is a structural block diagram of the present invention;

[0040] Figure 2 This is the energy harvesting circuit diagram of this utility model;

[0041] Figure 3 This is a schematic diagram of the process for adjusting the adaptive working mode of the microcontroller of this utility model. Detailed Implementation

[0042] To make the technical means, creative features, objectives and effects of the embodiments of this application easier to understand, the embodiments of this application are further described below in conjunction with the figures and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the embodiments of this application and are not intended to limit the embodiments of this application.

[0043] Please see Figure 1 An adaptive CT sensor includes a CT sensor, an energy harvesting circuit, a power management unit, a microcontroller unit, a temperature sensor, and a wireless communication module.

[0044] The output of the energy harvesting circuit is connected to the power management unit; the output of the power management unit is connected to the microcontroller unit; the microcontroller unit is connected to the temperature sensor; and the microcontroller is connected to the wireless communication module.

[0045] The CT sensor is the basic structure, with a central hole for the conductor through which the current to be measured (primary side) passes. When an alternating current flows through the primary conductor, according to the law of electromagnetic induction, a secondary current or voltage, reduced according to the turns ratio, will be induced in the secondary coil wound on the magnetic core.

[0046] The output of the secondary coil of this invention is used not only for current measurement but also as an energy source.

[0047] The microcontroller unit includes a microcontroller; the signal output terminal of the temperature sensor is connected to the digital interface of the microcontroller unit.

[0048] The microcontroller is the control core of the entire system. It integrates energy management and adaptive algorithms, signal acquisition and processing modules, wireless communication protocol stack and data processing modules, system scheduling and control modules, and calibration and configuration modules. It is powered by the power management unit and its main tasks include: periodically reading temperature data from the temperature sensor; processing signals from the secondary coil to obtain current values; and executing adaptive logic based on the energy level information obtained from the power management unit.

[0049] The temperature sensor uses an integrated temperature sensor chip with digital output, which has better anti-interference capability than analog signals. The temperature sensor uses a low-power model, such as the JHM3012 from Beijing Jiuhao Electronics. A bypass capacitor, such as a 0.1μF ceramic capacitor, is placed close to the chip at the VCC pin of the temperature sensor to provide a stable power supply for filtering out high-frequency noise.

[0050] Temperature sensors are installed near the CT core, secondary coil, or primary conductor to accurately measure the temperature of hot spots that may be caused by high current or poor contact.

[0051] The wireless communication module employs low-power wireless communication technology, selected from at least one of LoRa, NB-IoT, Zigbee, or BLE, to adapt to situations where energy harvesting power is limited. The microcontroller controls the wireless communication module to package the processed current and temperature data and transmit it according to a preset protocol.

[0052] Please see Figure 2 The energy harvesting circuit includes a rectifier circuit and an energy storage element circuit;

[0053] The rectifier circuit includes the secondary coil of the CT sensor, rectifier bridge D1, and capacitor C1; the two ends of the secondary coil of the CT sensor are connected to the two AC input terminals of rectifier bridge D1, and the positive and negative output terminals of rectifier bridge D1 are connected to the positive and negative terminals of capacitor C1, respectively.

[0054] The energy storage element circuit includes a capacitor C2 and a diode U2. The positive and negative terminals of capacitor C2 are connected to the positive and negative terminals of capacitor C1, respectively. A diode U2 is connected in series between the positive terminals of capacitor C2 and capacitor C1.

[0055] The energy harvesting circuit converts the alternating current induced by the secondary coil into pulsating direct current, which is then filtered by the filter capacitor C1. The filtered direct current can be used to charge the energy storage element capacitor C2.

[0056] The power management unit is connected to the output of the energy harvesting circuit. The power management unit includes capacitor C3, capacitor C4, and LDO chip U1. The positive and negative terminals of capacitor C3 are connected to the positive and negative terminals of capacitor C2, respectively. The positive terminal of capacitor C3 is connected to the VIN pin of LDO chip U1, and the negative terminal of capacitor C3 is connected to the GND pin of LDO chip U1. The GND pin of LDO chip U1 is grounded. The VOUT pin of LDO chip U1 is connected to the output terminal, and capacitor C4 is connected between VOUT and GND of LDO chip U1.

[0057] At the heart of the power management unit is a high-efficiency voltage regulator that converts unstable or high voltages on energy storage components into stable voltages required for the operation of microcontrollers, temperature sensors, and wireless communication modules.

[0058] The power management unit also has a voltage monitoring function, which can provide the microcontroller with the current voltage information of the energy storage elements, reflecting the current available energy level.

[0059] Please see Figure 3 The microcontroller has a built-in energy management and adaptive algorithm; the energy management and adaptive algorithm can adaptively adjust the operating mode, including adjusting the sampling frequency of temperature and current data, and adjusting the frequency of wireless data transmission.

[0060] The microcontroller periodically reads the voltage V_C2 on the energy storage element through the power management unit, which directly reflects the current available energy level.

[0061] In terms of external power consumption, the microcontroller can be configured with several voltage thresholds to distinguish different operating modes, such as (V_crit, V_low, V_high):

[0062] When energy is sufficient (V_C2 is higher than V_high), set the high-performance mode: collect current and temperature data once per second, and send data once per minute through the wireless communication module.

[0063] When the energy level is moderate (V_C2 is determined to be between V_low and V_high), set the normal mode: reduce the sampling frequency, collect current and temperature data once every 10 seconds, and send data once every 10 minutes through the wireless communication module, or only send data when the data changes by a certain amount.

[0064] When the energy is low (determined by V_C2 being lower than V_low and higher than V_crit), set the low-power mode: only collect current data, or further reduce the sampling and transmission frequency. The total average power consumption of the system may be reduced by 60%-80% compared to the normal mode.

[0065] When energy is extremely low (V_C2 is lower than V_crit), set emergency mode: enter deep sleep mode, retain only wake-up detection at extremely low power, and the total average power consumption of the system may be reduced by 95%-99% compared to normal mode.

[0066] When the monitored voltage crosses a certain threshold, the state machine transitions, and the system enters a new energy state.

[0067] In terms of the microcontroller's own power consumption, an ultra-low power microcontroller, such as the Renesas RA4L1, is selected, and different low-power sleep modes are entered between tasks; when the energy is sufficient, the microcontroller uses shallow sleep modes such as WFI, and when the energy is low, it uses deep sleep modes such as STOP or Standby.

[0068] Through this design, the adaptive CT sensor of this invention can achieve integrated monitoring of key point current and temperature without the need for external power supply and signal lines, and transmit the data wirelessly. Its adaptive energy management strategy ensures stable system operation and efficient energy utilization under different primary current conditions.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. An adaptive CT sensor, comprising a CT sensor, an energy harvesting circuit, a power management unit, and a microcontroller unit, characterized in that: The energy harvesting circuit has its input terminal connected to the secondary coil of the CT sensor; The microcontroller unit includes a microcontroller; the output of the energy harvesting circuit is connected to the input of the power management unit; the output of the power management unit is connected to the microcontroller unit; the microcontroller unit is connected to a temperature sensor; and the microcontroller is connected to a wireless communication module. The temperature sensor uses an integrated temperature sensor chip with digital output; a bypass capacitor is placed close to the chip at the VCC pin of the temperature sensor. The temperature sensor is installed near the CT core, the secondary coil, or near the primary conductor.

2. The adaptive CT sensor according to claim 1, characterized in that: The energy harvesting circuit includes a rectifier circuit and an energy storage element circuit.

3. An adaptive CT sensor according to claim 2, characterized in that: The rectifier circuit includes a secondary coil of the CT sensor, a rectifier bridge D1, and a capacitor C1. The two ends of the secondary coil of the CT sensor are connected to the two AC input terminals of the rectifier bridge D1, and the positive and negative output terminals of the rectifier bridge D1 are connected to the positive and negative terminals of the capacitor C1, respectively.

4. An adaptive CT sensor according to claim 3, characterized in that: The energy storage element circuit includes a capacitor C2 and a diode U2; the positive and negative terminals of capacitor C2 are connected to the positive and negative terminals of capacitor C1, respectively, and a diode U2 is connected in series between the positive terminals of capacitor C2 and capacitor C1.

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