Nurul Arfah Che Mustapha

Parametric analysis for designing low voltage and low frequency energy harvester booster

This work presents an ultra-low voltage DC-DC boost converter vibration-based energy harvesting. A switching gate controlled concept is used which is well suited for low vibration-based frequency and voltage applications. The 0.1-0.5 V input voltage range is linearly increased with the increase of output voltage range, 4-22 V. The transient analysis is simulated to verify the optimum value of the inductive resistance, switching rise and fall times circuit under test. The 10 kΩ load circuit is using 160 μH inductor and 10 μF load capacitor. This voltage converter is suitable for energy harvesting applications in automotive, buried electronic devices for broadband frequency range from 1 kHz to 10 kHz.

Capacitance sensing and energy harvesting for wireless health monitoring system

In this work, a self-generated power capacitance measurement circuit for wireless health monitoring system is proposed. Hybrid energy from thermal and solar energy is expected to be used to supply the energy harvester. The present results has shown using low cost, off-the-shelf components, the capacitance measurement circuit is able to sense a linear capacitance range of 9.8 - 10.35 pF over 1.478 - 1.57 V output voltage range. This circuit also has low power consumption of 3.1 mW at frequency 40 kHz. This circuit is suitable for wireless health monitoring system.

Single supply differential capacitive sensor with energy harvester compatibility

This paper presents a single supply differential capacitive sensing technique suitable to be used with a hybrid energy harvester in providing power to the circuit. The proposed differential capacitive circuit is designed based on the available off-the-shelf components. Theoretical and experimental study has been carried out to observe the performance of the circuit for various excitation frequencies. Tests that were carried out include using excitation frequencies ranging with a 0.1 pF capacitance change. Results from 40 kHz up to 400 kHz show a high level of linearity up to a 0.999 R-squared value. Range of capacitance detection can be increased by controlling the feedback capacitor, Cf, and the filter components, Rd and Cd. The sensitivity range is from 0.004 to 0.122 mV per every fF change, with ± 5 % error. The circuit consumes 3.83 mW, with a 3.3 V supply voltage. This circuit is also suitable for a wireless sensing node application.

Parametric analysis of single boost converter for energy harvester

This paper presents a conventional DC-DC boost converter for low and wide voltage supply range, suitable for energy harvesting purpose. The output voltage can be increased by controlling the transistor switching frequency, duty cycle, inductance, load capacitor, rise, and fall time. Both computer simulation and experiment results are performed in details. Experiment results have shown an error less than 6 % with the simulation. A linear trend of output voltage in the range of 4 V to 49 V is successfully converted from 100 mV to 1.5 V input voltage using low switching frequency of 2 kHz. The circuit parameter for this voltage range are L = 100 μH, D = 50 %, tr = tf = 2.9 μs considering CL = 10 μF, and RL = 10 kΩ. This circuit is suitable for medium voltage range application such as in automotive, aircraft, industry, and wireless measurement system.

WIRELESS STRUCTURAL HEALTH MONITORING SYSTEM BY CAPACITOR SENSING TECHNIQUE

Structural health monitoring (SHM) is a method of localizing damage in infrastructures regarding structural strain, vibration or movements due to external contributing factors which mainly occur as a result of natural disasters. The need to analyze such occurrences can prevent potential damage of massive scale. A sensing system with high sensitivity is needed for reliable structural health monitoring. A capacitive sensing circuit is designed using off-the-self-components and transmit data wirelessly using XBee. The circuit can detect small changes of capacitance variation due to structure vibration.

Current behavior analysis of the single supply differential capacitive sensing

Differential capacitive sensing technique has gained popularity in capacitance measuring system due to its high symmetrical implementation, easy to be implemented using discrete components and has a characteristic of high linearity in its system. However, very few work has reported on the differential CVC system that is able to operate at a high frequency operation especially when using discrete method. In this work, a differential CVC is proposed using discrete single supply, suitable for energy harvesting and WSN application. The method has emphasised on the rectifier current behavior analysis of the capacitive sensing circuit. Using this method, sensitivity of 0.04933 mV per 1 ƒF capacitance change is achievable with low power consumption of 3.83 mW. The proposed method has also shown high linearity of R-squared value 0.99788 between 5 and 9.5 pF capacitance change. Finally, the recorded DC output voltage is in the range of 1.6505 to 1.8725 V output with working frequency of 200 kHz operation.

Parametric sweep analysis of medium voltage range boost converter for energy harvester application

This paper presents a parametric sweep analysis discussion on proposed DC-DC boost converter circuit for low and wide voltage supply range. Analysis is initially done using computer simulation and then tested with experimental work. Results are combined and discussed in details. In this work, effect of parameter such as input voltage, switching frequency and inductance is presented in details. A linear conversion has been observed in this work. Low DC input voltage of 100 mV to 1.5 V is used and successfully converts to up to 50 V in linear inclination, considering CL = 10 μF, and RL = 10 kΩ. The circuit parameter for this voltage range are L = 100 μH, D = 50 %, and 2 kHz frequency operation. This circuit can be used for energy harvesting purpose and medium voltage application such as aircraft, wireless measurement system and automotive.

Boost converter for low voltage energy harvesting applications: Basic component selection

Regulating energy from tiny sources such from ambient vibration to supply a continuous energy to power an electronics device is a beneficial and challenging work to do. Having very small energy usually less than 1 V, needs a boost circuit to power up the device. This paper shows that the passive components of a conventional boost converter play an important role to boost very small voltage. This paper also presents that switching frequency effects to boost voltage. Transient analyses have been performed using PSpice simulation tool to check the circuit response to various parameter changes. The proposed circuit with components L=160 μH, RL=10 kΩ and switching frequency fS=1 kHz with duty cycle D=0.5 results optimum performance of the circuit. This voltage converter is suitable for vibration energy harvesting having low frequency applications in kHz range. The application of this converter is expected to be in automotive, healthcare and industrial field.