New method for low field energy harvesting

22C-D060A103  Chu began working with energy harvesting technology for vibration and magnetic fields in 2016. From 2016 to 2021, it has been committed to the research of materials and devices based on traditional cantilever beam resonant structures. This is an energy collector structure with one end fixed and the other end free, and a mass block (magnet) is attached to the free end. This structure is driven by a free-end magnetic mass block, while contributing more than 90% of the equivalent mass. In this case, if the resonant frequency of 50 Hertz (Hz) of the resonator is to be maintained, it is difficult to enhance the magnetic-force coupling performance simply by increasing the mass of the free-end magnet. It is for this reason that most of the cantilever magnetic-mechanical-electrical devices currently studied are limited to energy harvesting for strong magnetic fields, that is, fields greater than 5 Ost (Oe). The World Health Organization states that the safe threshold of 50/60Hz alternating magnetic fields accessible to the public is 1Oe, and the size of stray magnetic fields in the environment is generally lower than this reference value. Therefore, it is also necessary to explore new principles and methods adapted to low field energy harvesting.

Based on the thinking of “how to reduce the equivalent 22C-D060A103  mass of the free magnetic mass block in the magnetic-mechanical-electrical energy capture device”, Chu Zhaoqiang boldly proposed a design idea of the two ends of the clamping beam. In this design, both ends of the magnetic-electromechanical energy capture device are fixed, and a second-order vibration mode is adopted to reduce the kinetic energy of the central magnetic mass block, thus reducing its contribution to the equivalent mass of the resonant system, and greatly improving the output performance of the system under 50Hz weak field conditions under the condition of increasing the magnet volume.

Experiments show that under the same excitation conditions of weak magnetic environment, the energy collector can output more than 2 times of the traditional cantilever beam structure in the same unit time, which can make the sensor without battery work normally and communicate with the mobile phone terminal.

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Chu Zhaoqiang said: “In scientific research work, the key role is often a small or even insignificant design method. But the source of this method must be based on long-term research and thought.”

In the future, it may be used for small underwater bionic platforms

“At present, this kind of energy 22C-D060A103  harvesting technology for magnetic fields has certain limitations in its application. Science always solves one problem and creates many new problems.” Chu Zhaoqiang told the Science and Technology Daily reporter that in the future, he will mainly consider further optimizing the parameter design of the two ends of the grip-magnetic-mechanic-electrical energy capture device in terms of material and geometry, further realizing the integration of increasing the adaptive range of magnetic field changes and miniaturization, and developing self-supplying magnetic field sensitive components. The application of intelligent perception of power transmission and transformation and topology relationship recognition of power distribution network provide key technologies.

At the same time, Chu Zhaoqiang said that the team will combine the 22C-D060A103  characteristics and advantages of Harbin Engineering University’s ship and sea scientific research, and in-depth study of small underwater bionic platforms such as underwater robot fish, unmanned underwater vehicles and other wireless energy supply technology based on ultrasound and magnetic field, which can not only solve the problem of energy “take” such as small bionic platforms, but also solve the problem of energy “supply”.

The “Marine magnetic Sensor and detection” team of the College of Underwater Acoustics and the innovation and development base of Harbin Engineering University, where Chu Zhaoqiang is located, was established in 2017 and has been growing continuously. Aiming at the basic theory, key technologies and engineering applications of multi-sensor detection of underwater targets, the team has comprehensively carried out technical research on basic magnetic materials, magnetic sensor development, underwater information perception and processing.