Frequency response locking of electromagnetic vibration-based energy harvesters using a switch with tuned duty cycle

Abstract It is proposed to tune linear electromagnetic vibration-based energy harvesters so that they will achieve an optimum case regardless of the base amplitude or excitation frequency of the environment. The author designed the optimum coil and load parameters as well as the optimum acceleration amplitude and vibration frequency of the magnet for known values of three mechanical parameters (spring constant, mass, and mechanical damping coefficient) so that the optimum parameters will remain constant upon switching. As the vibration frequency of the magnet deviates from the optimal value, the switch turns on and off to compensate for the deviation so that the maximum power entering the electrical domain does not change. The deviation is limited to frequency or base amplitude acceleration. Other optimum parameters are fixed values. They are designed so that they can handle the maximum power that is delivered to the electrical domain.