Limits...
Microfabrication and integration of a sol-gel PZT folded spring energy harvester.

Lueke J, Badr A, Lou E, Moussa WA - Sensors (Basel) (2015)

Bottom Line: A feasibility study was undertaken with the designed conditioning circuitry to determine the effect of the input parameters on the overall performance of the circuit.The efficiency and charging current must be balanced to achieve a high output and a reasonable output current.The development of the complete energy harvesting system allows for the direct integration of the energy harvesting technology into existing power management schemes for wireless sensing.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, University of Alberta, University of Alberta, Edmonton, AB T6G 2G8, Canada. lueke@ualberta.ca.

ABSTRACT
This paper presents the methodology and challenges experienced in the microfabrication, packaging, and integration of a fixed-fixed folded spring piezoelectric energy harvester. A variety of challenges were overcome in the fabrication of the energy harvesters, such as the diagnosis and rectification of sol-gel PZT film quality and adhesion issues. A packaging and integration methodology was developed to allow for the characterizing the harvesters under a base vibration. The conditioning circuitry developed allowed for a complete energy harvesting system, consisting a harvester, a voltage doubler, a voltage regulator and a NiMH battery. A feasibility study was undertaken with the designed conditioning circuitry to determine the effect of the input parameters on the overall performance of the circuit. It was found that the maximum efficiency does not correlate to the maximum charging current supplied to the battery. The efficiency and charging current must be balanced to achieve a high output and a reasonable output current. The development of the complete energy harvesting system allows for the direct integration of the energy harvesting technology into existing power management schemes for wireless sensing.

No MeSH data available.


Related in: MedlinePlus

The simulated and experimental efficiency behavior vs. battery voltage for three input voltage cases (3 V p-p, 4 V p-p, and 5 V p-p).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4507646&req=5

sensors-15-12218-f019: The simulated and experimental efficiency behavior vs. battery voltage for three input voltage cases (3 V p-p, 4 V p-p, and 5 V p-p).

Mentions: As shown in Figure 18, the efficiency of the conditioning circuit was measured at 16.6% to 27.5% for the three input frequency cases. The overall circuit efficiency decreases as the input frequency increases. This occurs due to the higher DC voltage output from the voltage doubler leading to a higher voltage difference between the input and output voltages on the voltage regulator. In the ideal situation, the input power (Iin × Vin) is equal to the output power (Iout × Vout). Therefore, the ratio between Iin and the quiescent current of the voltage regulator affects the efficiency of the regulator. In the 100 Hz case, the circuit was not able to operate at battery voltages lower than 1.1 V due to the output DC voltage level from the voltage doubler dropping below the minimum 1.6 V required by the voltage regulator. To aid in the operation of the circuit at low input frequencies, the input voltage or the current limiting resistance should increase. This will not only allow for the operation of the circuit at low input voltage frequency, but will lead to a higher voltage doubler efficiency. The voltage regulator dominates the overall efficiency of the circuit, varying between 35% and 72% efficiency, while the voltage doubler varies between 41% and 52% efficiency. Additionally, the overall circuit efficiency can be improved by increasing the efficiency of voltage doubler and voltage regulator circuits. The discrepancy between the simulation and experimental results are expected, and it is mainly due to the tolerance of the different components used in the experiment, also due to un-modeled physical parameters as the NiMH battery internal resistance. In addition, experimental errors shown in Figure 18, and following figures, are calculated based on the measurement errors in each quantity required to capture the efficiency. Lastly, in general, the efficiency of the circuit decreases as the battery voltage increases for all frequency cases examined, due to the reduction of the battery charging current as seen in Figure 17. The efficiency behavior of the circuit vs. the battery voltage for varying input voltages is shown in Figure 19.


Microfabrication and integration of a sol-gel PZT folded spring energy harvester.

Lueke J, Badr A, Lou E, Moussa WA - Sensors (Basel) (2015)

The simulated and experimental efficiency behavior vs. battery voltage for three input voltage cases (3 V p-p, 4 V p-p, and 5 V p-p).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4507646&req=5

sensors-15-12218-f019: The simulated and experimental efficiency behavior vs. battery voltage for three input voltage cases (3 V p-p, 4 V p-p, and 5 V p-p).
Mentions: As shown in Figure 18, the efficiency of the conditioning circuit was measured at 16.6% to 27.5% for the three input frequency cases. The overall circuit efficiency decreases as the input frequency increases. This occurs due to the higher DC voltage output from the voltage doubler leading to a higher voltage difference between the input and output voltages on the voltage regulator. In the ideal situation, the input power (Iin × Vin) is equal to the output power (Iout × Vout). Therefore, the ratio between Iin and the quiescent current of the voltage regulator affects the efficiency of the regulator. In the 100 Hz case, the circuit was not able to operate at battery voltages lower than 1.1 V due to the output DC voltage level from the voltage doubler dropping below the minimum 1.6 V required by the voltage regulator. To aid in the operation of the circuit at low input frequencies, the input voltage or the current limiting resistance should increase. This will not only allow for the operation of the circuit at low input voltage frequency, but will lead to a higher voltage doubler efficiency. The voltage regulator dominates the overall efficiency of the circuit, varying between 35% and 72% efficiency, while the voltage doubler varies between 41% and 52% efficiency. Additionally, the overall circuit efficiency can be improved by increasing the efficiency of voltage doubler and voltage regulator circuits. The discrepancy between the simulation and experimental results are expected, and it is mainly due to the tolerance of the different components used in the experiment, also due to un-modeled physical parameters as the NiMH battery internal resistance. In addition, experimental errors shown in Figure 18, and following figures, are calculated based on the measurement errors in each quantity required to capture the efficiency. Lastly, in general, the efficiency of the circuit decreases as the battery voltage increases for all frequency cases examined, due to the reduction of the battery charging current as seen in Figure 17. The efficiency behavior of the circuit vs. the battery voltage for varying input voltages is shown in Figure 19.

Bottom Line: A feasibility study was undertaken with the designed conditioning circuitry to determine the effect of the input parameters on the overall performance of the circuit.The efficiency and charging current must be balanced to achieve a high output and a reasonable output current.The development of the complete energy harvesting system allows for the direct integration of the energy harvesting technology into existing power management schemes for wireless sensing.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, University of Alberta, University of Alberta, Edmonton, AB T6G 2G8, Canada. lueke@ualberta.ca.

ABSTRACT
This paper presents the methodology and challenges experienced in the microfabrication, packaging, and integration of a fixed-fixed folded spring piezoelectric energy harvester. A variety of challenges were overcome in the fabrication of the energy harvesters, such as the diagnosis and rectification of sol-gel PZT film quality and adhesion issues. A packaging and integration methodology was developed to allow for the characterizing the harvesters under a base vibration. The conditioning circuitry developed allowed for a complete energy harvesting system, consisting a harvester, a voltage doubler, a voltage regulator and a NiMH battery. A feasibility study was undertaken with the designed conditioning circuitry to determine the effect of the input parameters on the overall performance of the circuit. It was found that the maximum efficiency does not correlate to the maximum charging current supplied to the battery. The efficiency and charging current must be balanced to achieve a high output and a reasonable output current. The development of the complete energy harvesting system allows for the direct integration of the energy harvesting technology into existing power management schemes for wireless sensing.

No MeSH data available.


Related in: MedlinePlus