Last update: 28.02.2014
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SMART Ultrasonic Resonant Power System (SURPS ) - powering and data interface through ultrasonic vibrations
Energy Harvesting process is very practical using magnetostrictive and electrostrictive - materials. Under the influence of adequately strong magnetic and electric fields rapidly change their size and which are characterized by the reversed effect that under load produce a magnetic or electrical fields . Ultrasonic power transmission is a new method dedicated for Energy Harvesting and can provide electrical power and digital interface at once, by use of mechanical energy for wireless microprocessor sensors without typical radio transmissions in this case. The power transmission process through ultrasonic mechanical vibration using SMART materials is inaudible to humans. The efficiency values of transfer energy from actuator to harvester via mechanical construction is relatively high. This led to the practical use of such methods as power supply of 32bit microprocessor in special cases when powering by cables and radiotransmitionare not allowed like in a vacuum vessel. SURPS consists of the actuators which are processing electrical energy into mechanical vibrations and harvester devices which are responsible for the reverse process. Transfer of mechanical energy takes place by the generation of ultrasonic pure sinusoidal waves
bythe actuator and collection of this wave by the stimulated magneto– or electrostrictive material which is placed inside the harvester device. Due to this fact it is possible to transfer energy even far away from the actuator.
Block diagram of the SURPS used for the transmission of electrical power and data
in specific mechanical structures
Method of data transmission
Data transfer is made by the F2F-AM algorithm. Data transfer bitrate is much lower than the ultrasonic resonance frequency of the mechanical structure and can reach up to 1000bps. Higher data throughput can be achieved by using another modulation technique. Based on the result analysis for different resonant power supplies, it can be stated that it is possible to transfer the energy on a large distances without usage of electrical wires. However, the location of receiving harvester devices cannot be random and depends from the vibrations wavelengt.
Summary of the real encoded data signal and power supply acquired on transmission rail of the microprocessor system and AM decoder powered from harvesters
The software for scanning frequency response of actuator-harvester mechanical coupled system
The SURPS software window screen
The main features of the system include:
- generating a certain frequency in mechanical construction using DDS,
- high resolution scanning of a specified range of frequencies using the actuator-harvester system,
- possibility to read the actual voltage value (RMS) from the harvester stages,
- possibility to use some of the functions both for electro and magnetostrictive devices,
- multinodes configuration capability,
- data transmission between the actuator and the harvester in both directions (Tx, Rx).
Practical use of investigated ultrasonic power transmission methods
It was significant to consider and propose practical applications for devices based on the SURPS. Due to the fact that there are not many researches that would be dedicated to applications that using transfer of electrical power through ultrasonic mechanical vibration system it was important to check if the usage of the SURPS in technological processes would be effective. The powering of CORTEX M3 32-bit microcontroller through the SURPS was chosen in selected applications:
- double rail 1m long construction, with magnetostrictive actuator-harvester system with mechanical resonance (more than 20kHz),
- industrial single rail up 6m long for higher power transmission based on piezo actuator-magnetostrictive harvester system,
- power supplying through the metal and glass wall with thickness above 3mm,
- powering of „swimming” wireless sensor through the metal wall, glass wall and liquid inside reservoir.
Frequency response of the transfer of energy through the twin rail construction with magnetostrictive devices
Power supply using ultrasonic wave generated by the electrostrictive actuator and the magnetostrictive harvester device on the rail length 6m
Frequency response of the transfer of energy through the wall of the pressure vessel: actuator piezoelectric, magnetostrictive harvester
Frequency response of the transfer of energy through the glass wall in a hermetically sealed container: magnetostrictive actator, piezoelectric harvester
Power supplied „swimming” energy harvester systems by the mechanical supersonic vibrations from fluid in the reservoir
Demonstrator of supply through the glass wall and ultrasonic vibrations in fluid
Conclusion
Trends that appeared nowadays in ultrasonics subject area are focused on development devices that could be used in military, aerospace or customer markets. That emphasises the importance of SUPRS. In order to this situation it would be right action to add the utrasonic power transmission subject to the education programme for future engineers.
Simultaneous electrical power and data transmission system based on
a single magnetostrictive actuator and two magnetostrictive harvesters in the series configuration
Powering on industrial single rail based on electro- and magnetostrictive devices
Powering and data interface of the microprocessor wireless system, from the energy in the form of ultrasonic vibrations through the wall of the high - pressure reservoir
Demonstrator for supply and data transmission through the glass wall in
a hermetically sealed container
