A piezohydraulic generator for vibration energy harvesting

Abstract

To improve energy generating capability and reliability/strength, a novel piezohydraulic generator for low frequency vibration was presented. The piezohydraulic generator consisted mainly of a double-rod hydraulic cylinder for conversion of vibration energy to fluid energy and piezodiscs for conversion of the fluidic energy to electric energy. A vibration function and energy-conversion model of the generator was established based on theory of vibration analysis and simulated to obtain the influence of backpressure on energy generation as well as optimal frequency. The analysis results show that both the energy generation and optimal frequency increases with the rising of backpressure under given other parameters. A piezohydraulic harvester was fabricated and tested at different backpressure. Both the optimal frequency and the relative peak voltage/power increase with the rising of backpressure. At 0.2 MPa and 0.8 MPa, the peak-voltage and the relative optimal-frequency are 9 V/11 Hz and 112 V/17.5 Hz respectively. Similarly, the peak-power and the relative optimal-frequency are 0.58 mW/13 Hz and 11.63 mW/17 Hz respectively. The research results indicate that a piezohydraulic generator can be used to harvest energy from a low-frequency and high-level vibration source.

Review of vibration-based energy harvesting technology: Mechanism and architectural approach

“…As represented in Figure 29A, vibration force excitations-which the piston compressed and reboundedwere obtained while driving on an uneven road. 110 109 In another study, a maximum output power of 248.8 W was harvested under excitation with a frequency of 2 Hz, amplitude of 8 mm, and load resistance of 7.5 Ω.…”

“…At a test frequency of 13 Hz, the optimal voltage was 81.6 V, with a hydraulic pressure of 0.2 MPa and proof mass of 10 kg; voltage output were consistent around 40 V at 28, 35, and 30 Hz. 110…”

Design and implementation of an energy harvester interface circuit using ultra-low power piezo bending generator

“…Piezoelectricity has been identified to have capability to convert waste energy into useful electricity without 'refueling'. The only drawback to the mechanism is the low output power, however with the evolvement of power electronic drives the system mechanism can be improved significantly [16]. From another point of view, the performance of the developed system is limited by the discrepancy of the vibrator mechanism.…”