Aspects of the present disclosure describe systems, methods, and structures that scavenge mechanical energy to provide electrical energy to a wearable, where the mechanical energy is scavenged by a bending-strain-based transducer that includes a non-resonant energy harvester. By employing a non-resonant energy harvester that operates in bending mode, more electrical energy can be generated that possible with prior-art energy harvesters. In some embodiments, the output of a bending-strain-based transducer element is used for both energy scavenging and as a sensor signal indicative of a user parameter, such as a step, respiration rate, heart rate, weight and the like. In some embodiments, a transducer element includes a plurality of piezoelectric layers that are electrically connected in parallel to increase the energy and/or power provided by the transducer element.

The invention relates to a miniature kinetic energy harvester (1) for generating electrical energy, comprising: —a support (2), —a first element (3) having walls (32-35) surrounding at least one cavity (31), —at least one spring (4) mounted between the first element (3) and the support (2), the spring (4) being arranged so that the first element (3) may be brought into oscillation relative to the support (2) according to at least one direction (X) of oscillation, —a transducer (5) arranged between the first element (3) and the support (2) for converting oscillation of the first element (3) relative to the support (2) into an electrical signal, —at least one second element (7) housed within the cavity (31) and mounted to freely move within the cavity (31) relative to the first element (3) so as to impact the walls (32-35) of the cavity (31) when the harvester (1) is subjected to vibrations.

Micro-Electro-Mechanical System (MEMS) devices for harvesting sound energy and methods for fabricating MEMS devices for harvesting sound energy are provided. In an embodiment, a method for fabricating a MEMS device for harvesting sound energy includes forming a pressure sensitive MEMS structure disposed over a semiconductor substrate and including a suspended structure in a cavity. Further, the method includes etching the semiconductor substrate to form an acoustic port through the semiconductor substrate configured to allow acoustic pressure to deflect the suspended structure.

Hybrid energy harvesting devices that harvest vibrational energy over a broad frequency spectrum using several different energy harvesting mechanisms that are operable over different frequency ranges. In one embodiment, a device uses an inductive current generator to convert vibrational energy at lower frequencies to electrical energy, and also uses one or more piezoelectric charge generators to convert vibrational energy at higher frequencies to electrical energy. The electrical energy produced by these different mechanisms is provided to a controller which processes the input energy and generates an output which is applied to an energy store such as a battery. The energy stored in the battery can then be drawn by a wireless sensor or other device. The energy harvesting device may have the same form factor as a conventional battery to allow installation in battery-powered equipment without modification.

An energy harvesting device harvests energy from an energy source, and includes an inductor and a control switch coupled in series, and a control module. The series connection of the inductor and the control switch is adapted to be coupled to the energy source in parallel or in series. The control module controls the control switch such that the control switch starts to operate in an ON state for a predetermined time period from a transition time point during each predetermined cycle starting from a start time point, and such that a time difference between the transition time point and the start time point is variable. The control module obtains an output power of the energy source, and adjusts the time difference such that the output power of the energy source is increased.

An energy harvester comprising a mass that is subjectable to environmental forces for bringing it into the status of a moving mass, and means linked to the mass for converting and storing of energy embodied in the moving mass, which means are arranged for subsequent release of said energy, wherein the mass is part of a compliant system comprising a frame and first and second elastic beams connecting the mass to the frame, wherein the first and second elastic beams are provided with opposite stiffnesses so as to arrange that in a predefined range of excursions of the moving mass, said mass experiences a preselected stiffness.

An energy harvester for converting vibration energy into electrical energy and harvesting the electrical energy includes: a base; a clamping structure which is supported by the base and is spaced apart from the base; an elastic member which is disposed between the base and the clamping structure and allows the clamping structure to be elastically moved relative to the base; and a cantilever structure including a cantilever beam having one side fixed to the clamping structure and the other side which is elastically bendable, and a mass body disposed on the cantilever beam.

The inventive concept discloses a piezoelectric energy harvesting array and a method of manufacturing the same. The manufacturing method may include forming a plurality of piezoelectric energy harvesting devices; connecting masses to one side of the piezoelectric energy harvesting devices and connecting the other side of the piezoelectric energy harvesting devices facing the masses to a base; and individually tuning a resonant frequency of each of the piezoelectric energy harvesting devices to prevent mismatch of resonant frequency when the masses vibrate.

A power generator including: a first vibration system in which a first mass member is elastically supported by a first spring member; and a second vibration system in which a second mass member is elastically supported by a second spring member, the first and second vibration systems providing a multiple-degree-of-freedom vibration system. A power generating element disposed between the first and second mass members is configured to convert vibration energy input to the first vibration system and the second vibration system from a vibrating member to electrical energy. A resonance frequency of the first vibration system is a frequency lower than 1/√2 times a frequency of a vibration input to the first vibration system from the vibrating member. A loss factor of the first spring member of the first vibration system is at least 0.01 but not greater than 0.2.

Provided is a self-resonance tuning piezoelectric energy harvester. The self-resonance tuning piezoelectric energy harvester includes a piezoelectric beam which extends along a horizontal direction, a fixing element which fixes two ends of the piezoelectric beam, and a mass which is connected to the piezoelectric beam movably along the piezoelectric beam, wherein the mass includes a through-hole through which the piezoelectric beam passes, and makes the movement through the through-hole. According to the principle of continuous movement to the resonance position, the mass of the self-resonance tuning piezoelectric energy harvester induces the piezoelectric beam to generate displacement to the maximum and maximize the electricity production capacity of the piezoelectric energy harvester.