Systems and methods for monitoring temperature of electrical conductor
A system ( 100 ) for monitoring a temperature of an electrical conductor of an electrical cable and including a temperature sensor unit ( 100 a ) and a transceiver unit ( 100 b ). The temperature sensor unit ( 100 a ) is located inside the first (semi)conductive layer and includes a micro-controller ( 120 ), a temperature sensor ( 110 ), an energy harvest sub-unit ( 140 ) and a wireless transmitter layer ( 130 ). The temperature sensor ( 110 ) is adapted to detect a first signal (S 1 ) representing temperature of the electrical conductor and to supply the first signal (S 1 ) to the micro-controller ( 120 ). The transceiver unit ( 100 b ) is located outside the first (semi)conductive layer and includes an energy transmitter ( 160 ) and a wireless receiver ( 150 ). The energy harvest sub-unit ( 140 ) is adapted to harvest electromagnetic power from the energy transmitter ( 160 ) and to provide electrical power to the micro-controller ( 120 ). The wireless transmitter ( 130 ) is adapted to being engaged with the wireless receiver ( 150 ) under the control of the micro-controller ( 120 ) to transmit a second signal (S 2 ) converted from the first signal (S 1 ) to the wireless receiver ( 150 ). The energy harvest sub-unit ( 140 ) and the wireless transmitter ( 130 ) are designed to have different working frequency.
1. A system for monitoring temperature of an electrical conductor enclosed in at least a first semi-conductive layer, the system comprising:
a temperature sensor unit located inside the first semi-conductive layer, and comprising a micro-controller, a temperature sensor, an energy harvest sub-unit and a wireless transmitter, and the temperature sensor adapted to detect a first signal representing temperature of the electrical conductor and to supply the first signal to the micro-controller; and
a transceiver unit located outside the first semi-conductive layer and comprising an energy transmitter and a wireless receiver;
wherein, the energy harvest sub-unit is adapted to harvest electromagnetic power from the energy transmitter and to provide electrical power to the micro-controller;
the wireless transmitter is adapted to being engaged with the wireless receiver under the control of the micro-controller to transmit a second signal converted from the first signal to the wireless receiver; and
the energy harvest sub-unit and the wireless transmitter are designed to have different working frequency, wherein a ratio of the working frequency of the wireless transmitter to that of the energy harvest sub-unit is larger than 100, wherein the energy harvest sub-unit has a working frequency in a range from 10 KHz to 990 KHz, and wherein the wireless transmitter has a working frequency in a range from 10 MHz to 10 GHz.
2. The system according to claim 1 , wherein the energy harvest sub-unit comprises a LC resonant circuit adapted to generate an AC power after triggered by the energy transmitter.
3. The system according to claim 2 , wherein the energy harvest sub-unit comprises a rectifier circuit adapted to convert the AC power to DC power.
4. The system according to claim 1 , wherein the temperature sensor is in direct contact or in thermal contact with the electrical conductor.
5. The system according to claim 1 , wherein the first semi-conductive layer is enclosed by a second semi-conductive layer, the energy transmitter is located between the first semi-conductive layer and the second semi-conductive layer.
6. The system according to claim 5 , wherein the transceiver unit comprises a micro-controller located outside the second semi-conductive layer and connected with the energy transmitter via a wire.
7. The system according to claim 6 , wherein the wireless receiver is adapted to be located outside the second semi-conductive layer and to communicate with the micro-controller of the transceiver unit.
8. The system according to claim 7 , wherein the micro-controller of the transceiver unit is configured to determine the temperature of the electrical conductor based on the received second signal.
9. A method of monitoring temperature of an electrical conductor enclosed in at least a first semi-conductive layer, comprising the steps of:
harvesting electrical power and providing the electrical power to a first micro-controller by an energy harvest sub-unit working on a first working frequency, the first micro-controller and the energy harvest sub-unit located inside the first (semi)conductive layer;
detecting a first signal representing temperature of the electrical conductor by a temperature sensor unit located inside the first semi-conductive layer;
converting the first signal by the first micro-controller into a second signal applicable of being transmitted via a wireless way; and
transmitting the second signal by a wireless transmitter to a wireless receiver located outside the first semi-conductive layer, the wireless transmitter located inside the first semi-conductive layer and working on a second working frequency different from the first working frequency, wherein a ratio of the second working frequency to the first working frequency is larger than 100, wherein the energy harvest sub-unit has a working frequency in a range from 10 KHz to 990 KHz, and wherein the wireless transmitter has a working frequency in a range from 10 MHz to 10 GHz.
10. The method according to claim 9 , wherein the harvesting step includes a sub-step of emitting a trigger signal by an energy transmitter located outside the first semi-conductive layer to trigger the energy harvest sub-unit to oscillate to generate AC power.
11. The method according to claim 9 , comprising the step of determining the temperature of the electrical conductor based on the second signal by a second micro-controller located outside the first semi-conductive layer.