The continuous advancements in semiconductor manufacturing technologies have resulted in major innovations in electronic devices such as sensors, portable electronics, etc. Although the industrial market for wireless devices is growing rapidly, the typical wireless sensors and transmitters require periodic maintenance and are less energy-efficient, which has created the need to develop alternative and tenable power solutions for continuous functionality of wireless sensor networks (WSNs) and micro-electromechanical systems (MEMS) and Internet of Things (IoT).

Vibration Energy Harvesting Systems

Vibration energy harvesting systems are considered as promising solutions to counter the replacement of batteries of electronic devices that are difficult to service one deployed. Since vibration energy is present in abundance in atmosphere, several different mechanisms such as piezoelectric fibres and electromagnetic induction can be utilized to harvest the energy to create other efficient energy storage methodologies. The ambient vibrations are generally multi-modal harvesting configurations, which can be exploited to transform mechanical to electrical energy. Vibration energy harvesting is already popular and widespread in many sectors emerging as the go-to alternative to batteries when it comes to sensors and IoT devices.  Not only energy harvesting is sustainable and renewable source of energy, but it is also extremely promising, cheap, and efficient option to power small circuits.

Vibration energy technique is a method to scavenge energy from unwanted vibration occurrences such as motion of vehicles on bridges, working of machinery, etc., which are considered as residual energies. Since the vibration energy is employed from the environment for harvesting, it is considered as “free energy” that can empower small-scale devices. For converting mechanical energy into electrical energy, vibration motion needs to be integrated with a generator or different transduction mechanisms. Vibration energy harvesting gives a long-term solution to drive remote devices such as health monitoring devices, low power wearable sensor, ECG machine, serum analyser, MRI machine, etc.

According to TechSci Research report on “Global Vibration Energy Harvesting Systems Market By Product (Nonlinear Systems, Rotational Systems & Linear Systems,), By Application (Transportation, Power Generation, Industrial, Building & Home Automation & Others), By Region, Competition, Forecast & Opportunities, 2024”, Global vibration energy harvesting systems market is anticipated to reach around USD253 million by 2024, on account of increasing demand for power-efficient and durable systems that require minimum or no maintenance. Extensive implementation of IoT devices in automation and energy harvesting technology in building and home automation, in addition to increasing focus on green energy and favourable government initiatives, are expected to positively influence the global vibration energy harvesting systems market in coming years.

Advantages of Vibration Energy Harvesting

Energy can neither be created nor destroyed, it can only be transferred. Following this principal, various energy harvesting system have enabled the transition of waste energy into clean energy. Some of the features of vibration energy harvesting include

·         Utilizes low-grade energy or residual energy to power electronics with low power requirements

·         Provides environmental benefits as the energy generation does not require exploitation of resources

·         Innovations in energy harvesting techniques help provide scalability to technology

·         Eliminates the replacement and maintenance of batteries in medical implants, which was cited as a big problem

·         Potential applications of energy harvesting system include HVAC control, security, fire safety, industrial process, transportation, medical and military/aerospace

Limitation of energy harvesting systems

·         Low Output power and conversion efficiency

·         Device cannot operate in unstable vibration energy

·         Price of micropower generators is relatively high compared to batteries

·         Environmental energy harvesting technologies are still not mature

·         Limited acceptance in the market

Technologies used for Vibration Energy Harvesting

Electromagnetic Energy Harvesting (EMEH)

The EMEH configuration is broadly subdivided into moving coil type, moving magnet type, and resonant type. The power output depends on the configuration, properties of material, and transducer size. In EMEH, the mechanical energy is converted into electrical energy during the occurrence of relative motion between magnetized body and the conductive coil. The magnetic circuit required to implement in this configuration requires a magnetic field, which is either generated by an electromagnet or permanent magnet. Since permanent magnets do not require power, they are more suitable for low power devices. To enhance the efficiency of the EMEH, decreasing resonant frequency and widening frequency bandwidth can work efficiently. Another method to increase bandwidth is by introducing multi-degrees of freedom system in the excitation structure and non-linearity into the system, hybrid transduction, tuning, and multi-modal arrays. The EMEH functions best when its excitation is periodic in nature and size is larger.

Magnetostrictive EH (MSEH)

MSEH generates electrical energy from kinetic energy in two steps, through the magneto-mechanical coupling and electro-magnetic coupling, following Villari/Magnetoelastic effect. Through MSEH technique, first the mechanical energy is converted into magnetic energy through magneto-mechanical coupling and then the magnetic energy is transformed into electrical energy with electromagnetic coupling. The magneto strictive materials used in the configuration of MSEH are small ferromagnetic materials with small magnetic moment such as iron, cobalt, and nickel. As there is motion between the internal electrons of ferromagnetic atoms, the materials can easily change their shape or size when an external magnetic field is applied to them, and this effect is known as Joule’s effect. Whereas when magnetic field is applied to magneto strictive materials, the orientation of magnetic field changes with change in magnetic field, known as Villari Effect. The change in magnetic flux with time when electromotive force is induced, leads to the generation of electricity. 

Piezoelectric Energy harvesting (PEH)

PEH converts the vibration energy to electrical energy when the deformation of structures occurs. The piezoelectric effect is a unique property of material which is divided into two types, direct effect, and converse effect. When the sensation of mechanical stress or strain generates an electric field, it leads to direct piezoelectric effect. When reverse applied electric field introduces the deformation of material and acts as an actuator, it leads to converse piezoelectric effect. Some of the examples of piezoelectric materials used in the configuration of energy harvesting are Berlinite, Quartz, Lead Zirconate Titanate and Aluminium Nitride, which are available in the form of crystal, ceramics, polymers, or thin films. The piezoelectric materials can be used for both high and low power applications. Although a wide range of options are available for Vibration Energy Harvesting, some of the factors need to be considered while choosing the most suitable material such as piezoelectric voltage constant and strain constant. For PE energy harvesting system, the beam is attached with an active piezoelectric layer, and a resistive load is connected to it followed by conductive electrodes to cover the piezoelectric material for voltage output. The energy harvesting utilizing piezoelectric as a transducer is three to five times more than other types of devices. The compact size of PEH makes the whole process of harvesting convenient and effective.

Electrostatic Energy Harvesting (ESEH)

Electrostatic, also known as triboelectric converts vibration energy to electrical energy with a two-step conversion, electrical effect, and mechanical effect. Utilizing motion between two surfaces of charged capacitor which results in changes in capacitor potential difference, the electrostatic generates static electricity. Since most materials in our surroundings have triboelectrification effect, the material availability and area of choice are huge, but for ESEH configuration, the materials need to be arranged in their tendency towards losing or gaining electrons. There are two types of ESEH, electret-free and electret-based. In case of electret-free ESEH, the energy conversion cycle is used to convert mechanical energy into electricity by voltage constraint cycle for maximum power output. In case of electret based ESEH, electret layers are polarized to capacitors for energy generation. The major benefit of ESEH is the production of extremely high voltage due to high internal impedance, which can be distributed to long distances without power loss.

Conclusion

With the increasing adoption of IoT technology, the society will inevitably enter the Trillion Sensor Device within a few years. Growing concerns about environment and strong demand for sustainable energy sources are some of the driving factors fuelling the growth of Global Vibration Energy System market. From busy roads to electricity grid, walking movements to vehicular traffic, the mechanical energy can be tapped from a variety of environmental factors. Besides growing demand for building and home automation owing to the factors such as growing number of smart cities and increasing investment in building infrastructure is expected to propel Global Vibration Energy Harvesting Market in the coming years.

According to TechSci research report on “Global Vibration Monitoring Market By Offering (Hardware, Software and Services), By Monitoring Process (Online and Portable), By System Type (Embedded Systems, Vibration Meters and Vibration Analysers), By Industry (Energy & Power, Chemical, Automotive, Food & Beverages, Oil & Gas, Marine, Pulp & Paper, Aerospace & Defence and Others), By Company and By Geography, Forecast & Opportunities, 2025”, Global vibration monitoring market is expected to reach USD 1.82 Billion by 2025, in value terms, growing at a CAGR of over 5% during 2021-2025. The growth of market is being driven by growing consciousness towards predictive maintenance, technological advancements, growing drift of remote monitoring through wireless systems, penetration of smart workshops and growing demand from developing applications.