Capacitor Principle Research Articles

Summary of MEMS Capacitive Accelerometer

Micro-Electro-Mechanical System (MEMS) accelerometer (MEMS accelerometer), as an important MEMS device, has been widely used in the field of high-precision electronic technology and consumer electronic products. At present, the technology of MEMS accelerometer has been mature, and the sensor based on capacitance principle, piezoelectric effect, piezoresistive effect and other principles has been widely used in many aspects of national life and production and sustainable development. Combined with and according to all kinds of references, this paper briefly describes the shape composition and sensing principle of the MEMS capacitive accelerometer, enumerates the design and error optimization research of each research group for the sensor, and explains it with the relevant research data.

Mechanical Characterization of the Erythrocyte Membrane Using a Capacitor-Based Technique.

Pathological processes often change the mechanical properties of cells. Increased rigidity could be a marker of cellular malfunction. Erythrocytes are a type of cell that deforms to squeeze through tiny capillaries; changes in their rigidity can dramatically affect their functionality. Furthermore, differences in the homeostatic elasticity of the cell can be used as a tool for diagnosis and even for choosing the adequate treatment for some illnesses. More accurate types of equipment needed to study biomechanical phenomena at the single-cell level are very costly and thus out of reach for many laboratories around the world. This study presents a simple and low-cost technique to study the rigidity of red blood cells (RBCs) through the application of electric fields in a hand-made microfluidic chamber that uses a capacitor principle. As RBCs are deformed with the application of voltage, cells are observed under a light microscope. From mechanical force vs. deformation data, the elastic constant of the cells is determined. The results obtained with the capacitor-based method were compared with those obtained using optical tweezers, finding good agreement. In addition, P. falciparum-infected erythrocytes were tested with the electric field applicator. Our technique provides a simple means of testing the mechanical properties of individual cells.

A flexible precontact CNT-Al2O3 fiber sensor resistant to extreme temperatures.

As a new soft electronic product, a flexible precontact sensor provides spatial position sensing ability. However, the properties of traditional polymer materials change in industrial environments with extreme temperatures, which can cause the sensor function to decline or even fail. In this study, we propose a flexible fiber sensor based on the capacitor principle, which achieves a stable spatial positioning function and is not affected by a wide range of temperature changes. The fiber element of the sensor is obtained through the deposition of a flexible Al2O3 ceramic coating onto the surface of a carbon nanotube fiber (CNTF) via atomic layer deposition (ALD) technology. Coatings of different thicknesses (100 nm, 200 nm, and 300 nm) show different colors. The temperature resistance and flame retardancy of Al2O3 keep the morphology of the composite fiber unaffected by flame or high temperatures. Even at extreme temperatures (-78 °C to 500 °C), the sensor's sensing ability exhibits excellent stability. In addition, the spatial perception of the fibers remained viable after repeated bending (10 000 times). We demonstrate the potential of the sensor to acquire position information during high-temperature industrial pipe docking.

Design of Brushless DC Motor Driver Based on Bootstrap Circuit

Brushless DC (BLDC) motor is a three-phase motor that cannot work directly with DC current but requires electronic commutation to replace the brush function in DC motor. This paper aims to implement BLDC motor driver integration based on bootstrap circuit using Autodesk Eagle. The driver board consist of bootstrap circuit based on IR2110, MOSFETs, three voltage regulator, ESP32 microcontroller and ACS712 current sensor connection, logic level converter, and BLDC hall effect signal sensor conditioning. The research proposes bootstrap capacitor calculation based on charging/discharging capacitor principle and the minimum motor speed rotation. The implemented driver has 14x10 cm dimension tested to drive 24V/135W/6000rpm sensored BLDC motor using six steps commutation with pulse width modulation (PWM) inserted programmatically in ESP 32 to drive the high side MOSFET of the driver without AND gate circuit. The effect of pwm frequency and dutycycle variation to the speed and current of the motor is investigated. The results showed that the driver with both 12 V and 24 V voltage source and 68 μF bootstrap capacitor work optimally in 20 KHz PWM frequency both in open loop and closed loop speed control test. The motor reach 129 W for the largest power and 5250 rpm for the fastest speed in 24 V supply.

A novel measurement method for ash deposition based on coplanar capacitance principle: Theoretical, numerical and experimental studies

Monitoring for the fouling and slagging is critical to ensure the stable operation of gasification system. This paper proposes a novel measurement method for the ash deposition based on coplanar capacitance principle. A theoretical analysis of electrostatic field is conducted to obtain the correlation between the coplanar capacitance value and the deposition thickness. A finite element simulation is carried out to discuss the electric field characteristics of ash depositing on the coplanar capacitor. It shows that the capacitance value initially increases and tends to be constant with the increase of deposition thickness. The lower distance between positive and negative electrodes is favorable to the capacitance value (signal strength) but unfavorable to the maximum measurable thickness. Furthermore, a cold state experiment is conducted to verify the correctnesses of the theoretical and numerical models, and a hot state experiment is carried out to study the capacitance characteristics of sensor in the high temperature range of 700 °C–1200 °C. Results show that the permittivity of the material is lower under the higher test frequency, which leads to the lower capacitance value of sensor. The complex impedance curve of ash is conformed to IBLC dielectric model, this explains that the sensor capacitance increases with the test temperature increasing caused by the increase of permittivity due to the enlargement of ash grain. The change of Si/Al content has little effect on the dielectric properties of ash, however, the higher Fe2O3 content or the lower CaO content results into the lower ash fusion point, larger grain size, and thence higher permittivity and sensor capacitance. The maximum measurable thicknesses of the sensors in the cold state and hot state are 11.2 mm and 10.0 mm, respectively, which are independent with the test frequency, test temperature, and ash component.

Rebar corrosion detection in concrete based on capacitance principle

Rebar corrosion is one of the main reasons for the deterioration of RC structures and is of major concern in the construction industry. The detection of rebar corrosion in RC is essential for maintaining building safety and improving structural durability. In this study, rebar corrosion detection based on the capacitance principle was applied and analyzed using numerical simulations and acceleration tests. The critical corrosion point and rust-layer height can be detected using capacitive sensors. Capacitive sensors with different electrode placement positions exhibit several advantages and disadvantages. The electrodes of the capacitance sensor placed in the up and down positions more easily detected rebar corrosion, and the electrodes placed on the left and right sides exhibited higher sensitivity. A formula for the rebar rust-layer height and the relationship between the capacitance and corrosion thickness were established for non-uniform corrosion. Capacitance values were used to evaluate the compactness of the RC samples.

A novel switched capacitor-based multilevel inverter structure for renewable energy conversion system

Switched capacitor multilevel inverters (SCMLIs) are one of the popular solutions to mitigate the different limitations of conventional multilevel inverters (MLIs). A large number of innovative SCMLIs have been reported in literature in recent years. However, the large requirement of power switches, capacitors and large voltage stress across the switching devices are the major limitations of SCMLIs. In this paper, a novel MLI structure using switched capacitor principle has been proposed. It does not require any H-bridge circuit which reduces the switch voltage stress of the structure. It has the ability to produce 13-level output voltage with a boosting factor of 2. Further, the cascaded arrangement of the proposed structure has been realised. The structure requires a lower number of components as compared to the other SCMLIs. The operating principle, capacitor selection procedure and power losses analysis of the proposed 13-level structure have been presented. Extensive simulation and experimental studies have been conducted to validate the effectiveness of the proposed structure.

A novel rotation detection method based on the capacitance principle and triboelectric effect

With the rapid development of automation, more rotating monitoring equipment has been applied in modern industrial and civil fields. Conventional rotating monitoring sensors such as Hall rotating sensor and variable reluctance rotating sensor have a complex structure and their split structure is not convenient to layout. In the present study, a multi-layer structure rotation measurement sensor (MSRMS) is proposed based on the triboelectric effect and the capacitance principle. The proposed sensor consists of a stator and a rotor and measures the rotational speed based on the relative rotation between the copper electrode (Cu) on the stator and the polytetrafluoroethylene film on the rotor, and the variations of the electrostatic-induced voltage in the electrode, and can generate an alternating voltage waveform. When the rotor rotates, the correlation between the relative area of the stator and rotor electrode plates and the capacitor capacitance can be applied to measure the rotation angle. Then the MSRMS is applied to the programmable motor and the tripod for testing. It is found that the maximum error of the speed measurement is less than 0.2%. The coefficient of determination R 2 of the fitting for the distribution of the capacitance and the rotation angle is higher than 0.99688, which shows that capacitance is related to the rotation angle. The proposed sensor can not only measure the static rotation angle, but also dynamically monitor the speed and direction of rotation, and has a good application prospect.

Monitoring Kekenyalan Tahu Kedelai dengan Sensor Kapasitif Menggunakan Mikrokontroller Berbasis Android

Tofu has the best quality vegetable protein because it has the most complete amino acid composition and is believed to have high digestibility (85% -98%). According to SNI 01-3142-1998 and SII No. 0270-1990 testing criteria for soy tofu based on smell, taste, color, appearance, or texture. Tofu soybeans are prone to physical or texture damage due to factors such as inappropriate pH levels and insufficient storage which results in damaged tofu. Therefore in this study, it is proposed to determine the elasticity of soy tofu with the parameters tested are the pH level in the manufacture of soy tofu, the storage temperature, and the capacitance value to see how thick the tofu is with a capacitive sensor using the capacitor principle. Where the parallel plate capacitor is a capacitor consisting of two parallel metal plates. The test results of all sensors are sent to the database and will be displayed on the page on the Android application which will provide real-time sensor output information to the user. Based on the results of testing on this system using a pH sensor, the pH value is around 3-4 which indicates that the pH level used is very good for use in tofu processing, at pH 4.56 with storage at 29 ° C the highest elastic capacitance value is 3.58. In testing data delivery, the throughput value is 4336,217 b / s and the smallest delay value is 0.017ms because the smaller the delay value, the better the quality of data transmission because there will be no delay in sending data.

Calculation of the Energy of Capacitors for a Spot Welding Apparatus by a Numerical Method

This article provides information on the development of an adjustable spot welder implemented on the basis of the capacitor principle without a transformer. Also the scientific work considers the calculation of the energy of the capacitors for a spot welding apparatus using modern methods of numerical simulation and programming. The method of calculation is given, as well as a mathematical solution tool. The calculation results are compared with the experiment. Based on the data obtained, according to the results of calculations, work was carried out on a prototype, the result of which was an adjustable spot welder. It allows you to accurately and quickly weld nickel plates to lithium cells, creating full-fledged batteries from them, which are widely used in modern technology, including promising vehicles. The presence of sensors and a screen allows the operator to control the charging process and the direct operation of the unit, which simplifies the use of the device.

A Family of DC–DC Converters With High Step-Down Voltage Capability Based on the Valley-Fill Switched Capacitor Principle

In this article, a family of interleaved high-step-down dc-dc converters is proposed integrating the valley-fill switched capacitor structure and a double-series capacitor Buck converter. This integration generates three converters, which will be extensively explored herein via theoretical and experimental analysis. A complete theoretical analysis of the structures is presented in order to mathematically explain the physical operation of the proposed topologies. A design procedure is presented for the following specifications: 300 V/12 V input to output voltage, 100 W of power and a switching frequency of 100 kHz, and the results obtained are compared to state-of-the-art dc-dc converters that enable similar high-step-down operation.

Research on the detection of fouling and slagging in cold state based on capacitance principle

Aiming at the requirement of on-line monitoring for the fouling and slagging in the syngas cooler of coal gasifier, this paper proposes a detection method of deposition thickness based on the capacitance principle. A capacitance measurement rig for deposition detection is built to conduct a cold state simulation experiment. The coal ash and syrup are selected as medium to simulate the fouling and slagging in cold state. Two kinds of electrodes including single-electrode and double-electrode probes are used to measure the capacitance of deposition. The results show that the measured capacitance increases linearly with the increase of the deposition thickness for all the cases. The linear correlations between the capacitance value and the deposition thickness are obtained for ash and syrup under two kinds of electrodes, respectively. Verification tests show that the predicted deposition thicknesses by employing the linear correlations are basically consistent with the real thickness, and the maximum error is 5.15%. The detection error with single-electrode is less than that with double-electrode due to more deposition amount between two electrodes.

Technology Trend of Electric Double Layer Capacitor

Electric double layer capacitor is used for various applications because of its unique characteristics, such as high reliability, less environmentally-load and high rate capability. The present paper describes a basic principle, constitution, characteristics, applications and future prospects of electric double layer capacitor.

Further Study of the Sensing Ring Position on the Orifice-Type Capacitive Flow Sensor

The flow head of an orifice-type capacitive flow sensor for a conducting liquid consists of a vertically mounted metallic orifice plate in a horizontal pipeline made of insulating material and a rigidly grounded metallic ring or sensing ring placed surrounding the pipeline at a small distance from the orifice plate where the capacitance between the orifice plate and the sensing ring follows a linear relationship with flow rate as reported in the literature. In this paper, a further study on the effect of position of the sensing ring on the sensor capacitance has been carried out along with the modification of the simple parallel plate capacitance principle described in the earlier work by the real disk-type capacitance principle. From this paper, it has been observed that for any position of the sensing ring near the orifice plate, the sensor capacitance decreases linearly with the increase of flow rate and follows the modified capacitance principle similarly as that observed in earlier work. It has also been observed that the sensing ring distance-sensor capacitance product increases almost linearly with the increase of sensing ring distance. From the experimental study of the proposed orifice type capacitive flow sensors installed on two different pipelines, the said modified theory of the sensor appears to be verified in the present paper where the experimental results are reported.

Sensorless predictive current control with a charge balance current estimator for boost converters based on discrete‐time model considering current ripple

The performance of a sensorless predictive current controlled boost converter is usually susceptible to the accuracy of the employed converter and current estimator models. Since the accuracy of conventional current estimator would be degraded due to parasitic parameter variations, a charge balance current estimator (CBCE) is proposed to overcome this issue. Its estimation of peak inductor current is based on the charge balance principle of output capacitor and characteristics of inductor current ripple. Only one parasitic parameter - capacitor equivalent series resistance (ESR) is used in CBCE. Furthermore, the capacitor ESR is also estimated together with output load by a proposed equivalent load estimation scheme which can improve the current estimation accuracy. Besides, to achieve a high dynamic performance digital control, a discrete-time model considering current ripple is developed, in which the ripple is taken into account rather than treats inductor current as a constant in each switching cycle. It can achieve a higher accuracy than conventional averaged model, especially in the high-frequency region. Finally, its effectiveness is verified by simulation and experiment results.

Common-Ground-Type Transformerless Inverters for Single-Phase Solar Photovoltaic Systems

This paper proposes a family of novel flying capacitor transformerless inverters for single-phase photovoltaic (PV) systems. Each of the new topologies proposed is based on a flying capacitor principle and requires only four power switches and/or diodes, one capacitor, and a small filter at the output stage. A simple unipolar sinusoidal pulse width modulation technique is used to modulate the inverter to minimize the switching loss, output current ripple, and the filter requirements. In general, the main advantages of the new inverter topologies are: 1) the negative polarity of the PV is directly connected to the grid, and therefore, no leakage current; 2) reactive power compensation capability; and 3) the output ac voltage peak is equal to the input dc voltage (unlike neutral-point-clamped and derivative topologies, which requires twice the magnitude of the peak ac voltage). A complete description of the operating principle with modulation techniques, design guidelines, and comprehensive comparisons is presented to reveal the properties and limitations of each topology in detail. Finally, experimental results of 1-kVA prototypes are presented to prove the concept and theoretical analysis of the proposed inverter family for practical applications.

Consideration of the fringe effects of capacitors in micro accelerometer design

Capacitive micro accelerometer, as one of promising micro devices, utilizes the parallel-plate capacitor arrays to covert input acceleration into differential capacitance, so its characteristics highly depend on an accurate capacitance evaluation. The traditional capacitance formula used in macro-scale systems design could not meet the requirement of micro-scale field because the fringe effects of capacitors have great contribution to the total measured capacitance under a few millimeters of separation distance. In this paper, the theoretical equation of capacitance with fringe effects is utilized to design the sensitivity and nonlinearity of a capacitive micro accelerometer. The proposed analytical method provides a quantitative evaluation of sensing capacitance of micro accelerometers. Experimental results indicate that the theoretical design with fringe effects has a better agreement with experiments than ideal parallel-plate capacitor principle.

DESIGN DETECTION INSTRUMENT QUALITY DRY RUBBER In LATEX By CAPACITANCE PRINCIPLE USE MICROCONTROLER ATMega8

Research design detection instrument quality dry rubber by capacitance principle use microcontroler ATMega8 has purpose for knowing characteristic capacitance censor, making detection instrument and testing detection instrument in latex. This research has done by steps making capacitance censor, making acuisition data system, preparing train sample, taking data from train sample, processing and analysis data train sample, preparing test sample and implementation detection instrument in test sample. Result of characterization censor that is transfer function f = 120135e -0.312C Hz, has relation input and output really strong by correlation coefficient r = -0,99, has sensitivity 240.27 Hz/F and repeatability 98,95%. Result of testing show success instrument percentage for detection quality dry rubber in latex quality 1 is 100%, lateks quality 2 is 70%, and latex quality low is 90%.

Probe and Sensors Development for Level Measurement of Fats, Oils and Grease in Grease Boxes

The wide spread of food outlets has become an environmental and sanitation infrastructure problem, due to Fats, Oils and Grease (FOG). A grease box is used at the industrials facilities to collect the FOG, in a specific time window, while its quality is good for recycling (e.g., biodiesel) and it is economically valuable. After this period, it will be disposed at a cost. For the proper management of the grease boxes, it is necessary to know the quantity of FOG inside the boxes, which is a major problem, as the boxes are sealed and permanently filled with water. The lack of homogeneity of the FOG renders it not detectable by current probes for level detection in liquids. In this article, the design, development and testing of a set of probes for FOG level measurement, based on the principles used in sensors for the detection of liquids inside containers, is described. The most suitable probe, based on the capacitance principle, together with the necessary hardware and software modules for data acquisition and transmission, was developed and tested. After the development phase, the probe was integrated on a metropolitan system for FOG collection and grease box management in partnership with a grease box management company.

Non destructive fabric weight measurement using capacitance principle

Purpose The purpose of this paper is to design and develop an instrument for non-destructive fabric grams per square metre (GSM) measurement. This study uses the capacitance principle to obtain the fabric GSM. The relative permittivity of the sample fabrics changes the capacitance value. A relationship between capacitance and GSM that best fits the look-up table is obtained. Also, the developed system is applicable for all kind of fabrics both knitted and woven fabrics. The comparison study was carried out with existing test method. Design/methodology/approach The purpose of the study is to design and develop an instrument for non-destructive fabric GSM measurement. Findings The proposed non-destructive method of fabric GSM measurement using capacitance principle is designed, developed and tested. Also, the developed system is applicable for all kind of fabrics both knitted and woven fabrics. The comparison study was carried out with existing test method. Research limitations/implications The change in capacitance due to relative permittivity of the sample fabric is in pF range (10-12). The system can be further improved by using a capacitance sensor of sensitivity upto 1 fF (10-15). By doing so, the proposed system provides better results in terms of accuracy and resolution. The system developed can be further extended by making it online equipment which measures the fabric GSM instantaneously. Originality/value So far there is no non-destructive testing method available for fabric weight measurement. The newly designed and developed instrument is used to test the fabric both woven and knitted non-destructively.