Step-up Circuit Research Articles

Increase in Power Efficiency When Discharging Series Capacitors with a Step-Down Circuit Compared to Discharging Parallel Capacitors with a Step-Up Circuit

A discharging circuit with high energy efficiency is designed for supercapacitors. In this design, the capacitors are connected in parallel during charging and connected in series during discharging. With this method, the voltage of the capacitors in series becomes two times larger during discharging; thus, the step-down circuit can be used to produce the desired output voltage. The efficiency of the step-down circuit is four times larger than that of the step-up circuit in simulations. The experimental results agree well with the theoretical values. These results show that a step-down circuit is superior to a step-up circuit for extracting electrical energy from supercapacitors.

A Dual-Mode Hybrid Step-Up Converter with Stable Output for Vibration Energy Harvesting

A dual-mode hybrid step-up circuit for electromagnetic energy harvesting (EVEH) is proposed in this paper, with the merits of continuous output power delivery with and without external vibrations, simple architecture, and no need for extra circuits to start up. The proposed hybrid converter combines a multi-stage voltage multiplier (VM) with a boost regulator, which utilizes the winding inductance of the electromagnetic energy harvester as a boost inductor. With external vibration, the proposed circuit powers the load and stores energy in the super-capacitor through VM mode. When external vibration disappears, it automatically switches to boost mode and powers the load using the energy stored in the supercapacitor. For hybrid mode operation, the number of VM stages is optimized considering the following three aspects: sufficient voltage gains when vibration is on, time durations to provide constant power when vibration is off for as long as possible, and low losses at VM stage. A GaN-based dual-mode hybrid converter is built to verify the output regulation capability with an in-house-designed electromagnetic energy harvester. The outputs of the hybrid circuit achieve 4.05 V and 1.64 mW at a 100-Hz external vibration frequency and an acceleration of 0.7 g. The peak efficiency of the proposed hybrid converter reaches 60.7%. When external vibration disappears, the circuit is able to maintain a stable output for 13 s with a super-capacitor of 0.1 F.

Investigation of temperature gradient between ambient air and soil to power up wireless sensor network device using a thermoelectric generator

This paper proposes a study of an energy harvesting system for powering wireless sensor network (WSN) devices. The thermal energy harvesting system used is based on the thermal energy source between ambient air at the soil surface with five depth levels. Measurement was taken for 46 days in a garden area located in Melaka, Malaysia. A feasibility study of soil temperature measurement to obtain a temperature gradient can be used for harvesting by using thermoelectric generators (TEG) modules. Then, the efficiency of TEG with several different configurations based on temperature gradient data has been tested in the laboratory. The results revealed that the depth of soil 6 cm between sensors 1 and 3 will gave the best representation of level average temperature different around 1 ℃. Based on the temperature gradient data, the combination of three TEG SP1848 in a series connection with DC-DC step-up circuit DC1664 will produce an optimum voltage output of about 3 V. This output voltage is enough to operate low power IoT device derived from thermal energy.

Comparative Study of Adaptive Hamiltonian Control Laws for DC Microgrid Stabilization: An Fuel Cell Boost Converter

Future smart grids can be seen as a system of interlinked microgrids, including small-scale local power systems. They consist of main power sources, external loads, and energy storage devices. In these microgrids, the negative incremental impedance behavior of constant power loads (CPLs) is of major concern since it can lead to instability and oscillations. To cope with this issue, this article aims to propose a comparative study of adaptive Hamiltonian control laws, also known as interconnection and damping–assignment–passivity–based controllers (IDA-PBC). These control laws are developed to ensure the stability of the DC output voltage of a boost converter supplied by a proton exchange membrane fuel cell (PEMFC) source. To validate the develop control laws, experiments have been performed on a fit test bench including a real 2.5 kW PEMFC stack (hydrogen is supplied by a reformer engine), a DC-DC step-up circuit, and a real-time controller dSPACE (implementation of the control laws). Moreover, a comparative study has been carried out between the proposed three adaptive Hamiltonian control laws and a classic linear cascaded proportional–integral (PI) control law. The obtained results by simulations through MATLAB/SimulinkTM and experimentally have allowed demonstrating that the third Hamiltonian control law presents the best performances over the other control laws.

PERANCANGAN SISTEM KEAMANAN TAS RANSEL BERBASIS ESP8266 DENGAN NOTIFIKASI MENGGUNAKAN APLIKASI TELEGRAM

A backpack is a medium that functions as a storage for various valuables. In general, backpacks that are not equipped with a safety system can make them vulnerable to theft. This research resulted in a security system design to detect the location of the backpack and detect the backpack open by force with a notification using the telegram application. In this backpack security system will use components, namely light sensor (LDR), voltage sensor, ADS1115 module, unblox 6m GPS module, IC ESP8266, external modem, buzzer driver, stepup circuit, buzzer, battery and telegram application. The ESP8266- based backpack security system with notifications using the telegram application has several advantages, namely that it can provide a warning in the form of a buzzer alarm and notification on the teleram application if the backpack is forced to open, can track the position of the backpack in case of theft and if you don't remember the position of the backpack . The results of research on the backpack system are able to work according to predetermined working principles and data analysis is also in accordance with existing calculations.

Demonstrating the Scope of a Switched Supercapacitor Circuit for Energy Harvesting Powered Wireless Sensor Loads

This paper describes the design of a high-efficiency energy management system for low-power, low-voltage energy harvesting powered wireless sensor systems. With typical voltages of less than 1 V and power levels lower than 1 mW, there are significant challenges when applying energy harvesting sources to supply pulsed power levels of up to 120 mW at voltage levels of 1.8–4 V as required by wireless sensor loads. The proposed approach integrates energy storage elements within a voltage step-up circuit to produce a new high-efficiency energy management circuit that converts the energy produced by a low-power, low-voltage source into a series of high power pulses. An optimized switched supercapacitor energy buffer circuit including a self-powered control circuit is proposed. Efficiencies of up to 91% are shown for an indoor solar cell source with a power level of 0.5 mW, supplying an equivalent wireless sensor with pulsed power levels of 10–120 mW. This is significantly higher than 83% achieved for the dc–dc stage of the existing best solution under the same source conditions, but requires an additional conversion step to provide high power pulses.

A 1-MHz-Modified SEPIC With ZVS Characteristic and Low-Voltage Stress

A 1-MHz-modified single-ended primary-inductor converter (SEPIC) circuit is presented in this paper as an LED driver for automotive headlights. On the basis of traditional SEPIC, only a diode and two capacitors are added; therefore, the circuit structure is relatively simple and the volume is relatively small. High step-up capability is obtained with moderate duty cycle. Compared with traditional step-up circuit such as boost, low-voltage stress is gained which is beneficial to device selection. Zero-voltage switching is achieved at the same time to reduce switching loss. Planar inductors are used with the advantages of low profile and good thermal characteristic. Operational principle and parameters design process are introduced in detail. A 36-W prototype has been designed to demonstrate theoretical analysis. Obtained efficiency was up to 90.91% at full load.

Commutation Torque Ripple Reduction for Brushless DC Motor Based on an Auxiliary Step-Up Circuit

There exists torque ripple in the commutation process of brushless DC motor (BLDCM), which seriously restricts its application in the high-performance field. This paper proposes an auxiliary step-up circuit to suppress the commutation torque ripple of BLDCM, and the auxiliary step-up circuit consists of a transformer, a capacitor and a switch circuit. For effective suppression of the commutation torque ripple, the capacitor is charged in the non-commutation period. When the commutation occurs, the charged capacitor is added on the power source through a switch circuit to step up the dc-bus voltage in the commutation period, and the three-phase inverter is regulated to make the motor’s input voltage is equal to four times the back electromotive force (back EMF) amplitude. The auxiliary step-up circuit only transfers partial power required in the commutation process of the motor, and the capacity of the power components is reduced accordingly. The inductive energy stored in the transformer is returned to the power source in each switching cycle, which improves the energy utilization rate. In addition, this method can also shorten the commutation time. The validity and effectiveness of the proposed method is verified through experimental results.

(Invited) Paper-Based Printable Lactate/Glucose Biofuel Cell Toward Self-Powered Biosensor

A paper-based biofuel cell (PBFC) which is based on printing technologies, are attracting increasing attention as new energy harvesting systems for sensor tags, wearable biomedical devices, and small electrical devices [1-3]. The PBFC is also useful for a self-powered biosensing system [4-5] In this talk, I introduce a high power lactate/glucose PBFC, which was created by series and parallel array structures. The single PBFC was composed of a bioanode and a biocathode that were based on porous carbon electrodes constructed using porous carbon inks. The porous carbon material, namely MgO-templated carbon, has suitable mesopores for entrapping an enzyme whose redox center can approach the carbon surface with high probability. In addition, the long-term stability may be improved because the ellusion of the enzyme was suppressed by entrapping the enzyme in the mesopore. A 6-series/6-parallel lactate PBFC array, which is based on a new array structure, exhibited an output power of about 4.3 mW, and an open circuit voltage of about 3.6 V. For example, the present PBFC was able to light an LED directly, without the requirement of a step-up circuit board and we achieve a wireless transmitting of the information of lactate concentration with a smart phone. In the present study, I will show you our resent results about printable lactate/glucose self-powered biosensors. Acknowledgement This work was supported by JST-ASTEP Grant Number AS272S004a and JSPS KAKENHI Grant Number 17H02162. References C. W. N. Villarrubia, F. Soavi, C. Santoro, C. Arbizzani, A. Serov, S. Rojas-Carbonell, G. Gupta and P. Atanassov, Biosens. Bioelectron., 2016, 86, 459. M. J. González-Guerrero, F. J. del Campo, J. P. Esquivel, F. Giroud, S. D. Minteer and N. Sabaté, J. Power Sources, 2016, 326, 410. S. Li, Y. Wang, S. Ge, J. Yu and M. Yan, Biosens. Bioelectron., 2015, 71, 18. I. Shitanda, M. Momiyama, N. Watanabe, T. Tanaka, S. Tsujimura, Y. Hoshi, M. Itagaki, ChemElectroChem, 2017, 4, 2460.I. Shitanda, S. Nohara, Y. Hoshi, M. Itagaki, S. Tsujimura, J. Power Sources, 2017,

A Cascaded Multilevel Inverter Using Only One Battery with High-Frequency Link and Low-Rating-Voltage MOSFETs for Motor Drives in Electric Vehicles

Cascaded H-bridge (CHB) multilevel inverters are widely used in industrial applications, such as medium-voltage conversion and motor drives. However, the DC bus voltage in the electric vehicles is limited and it might not meet the requirements of the inverters for conventional motor drives. This paper presents a solution to drive the conventional motor (3Φ/AC 220 V) with inadequate DC bus voltage (DC 144 V) in an electric vehicle without any extra step-up circuits. The solution consists of a CHB inverter as a motor drive and a high-frequency (HF) transformer to balance the voltage. The multilevel CHB inverter improves the voltage and the current waveforms. High-frequency link (HFL) is used to create several isolated DC sources for the system and it can improve the power density. Besides, it replaces bulky line-transformers in the conventional CHB inverters, and the volume is reduced. Also, the inverter has bidirectional power flow ability, which can improve the efficiency in motor drives. As a result, the reduction of the step-up circuits is achieved and the topology can be used in the electric vehicles that are powered by only one 144 V-battery. The details and the principles of the control algorithm is discussed and an experiment based on a four-level CHB inverter with one DC 30 V power source is carried out to validate the proposed characteristics.

Lighting system design using green energy from living plants

Green energy is the energy generated from nature such as water, wind, solar and wave that aimed to reduce environmental damage or destruction, sustain the use of energy and natural resources as well as promote the use of renewable energy. This study aimed to analyse the electrical energy generated by the three types of living plants selected at the parking area of the Faculty of Technical and Vocational Education and design a lighting system for the parking area by using living plants as the source of energy generation. This study consisted two phases, Phase I: Analysing the energy generated from the living plants; and Phase II: designing the lighting system for the parking area phase using living plants. The result of the analysis of the energy produced by living plants showed that the selected living plants are able to produce energy with the sufficient amount needed by the lighting system at the parking area. Based on the analysis of the generation of energy from living plants, the lighting system was designed by using step-up circuit and the charging circuit. In conclusion, living plants should be fully utilized as part of the energy resources to generate energy.

Wearable Thermoelectric Generator With Copper Foam as the Heat Sink for Body Heat Harvesting

Wearable thermoelectric generator (TEG) is an attractive technology to enable self-powered electronics and sensors for healthcare and the Internet of Things through its ability to convert body heat into electricity. However, the actual inner temperature gradient in the thermoelectric legs is relatively small when a TEG is worn on the body, which leads to a low voltage and power generation. To enhance the output performance, the structural design of a wearable TEG with copper foam as the heat sink is proposed. A thermal resistance model was developed to investigate the effects of using copper foam heat sink on the heat transfer and performance of the TEG. In addition, for comparison, the inner temperature gradients and open-circuit voltages of the TEGs with and without plate-fin heat sink were analyzed. Then, these different TEGs were fabricated and tested using an experimental setup. The results showed that TEGs with heat sinks could generate greater open-circuit voltage and output power values, while the TEG with copper-foam heat sink achieved the highest power-to-weight ratio. Finally, a wearable TEG with copper-foam heat sink was connected to a step-up circuit and worn on the wrist to power a miniaturized accelerometer for body motion detection. The results demonstrated that the wearable TEG with the copper-foam heat sink design provided a potential pathway for the realization of electronics powered by harvesting the human body heat.

High step‐up passive absorption circuit used in non‐isolated high step‐up converter

To obtain a high step-up gain with high efficiency in distributed power sources application, such as photovoltaic (PV) and fuel cells, a passive absorption circuit with voltage step-up character is inserted in the interleaved flyback-forward converter for leakage energy recycle and voltage gain extension. By applying the high step-up passive-clamp circuit, the voltage spike on the metal-oxide semiconductor field-effect transistor is clamped and the energy stored inside the leakage inductance of the coupled inductor can be recycled to get high-output voltage. Moreover, it offers another design freedom to obtain higher voltage-conversion ratio. The operational principle and characteristics of the improved flyback-forward converter are presented, and verified experimentally with a 500 W prototype converter. The proposed high step-up passive-clamp can be widely used in high step-up DC-DC converter applications, and a new high step-up topology is deduced to illustrate the theoretical analysis.

Research on a New Control Scheme of Photovoltaic Grid Power Generation System

A new type of photovoltaic grid power generation system control scheme to solve the problems of the conventional photovoltaic grid power generation systems is presented. To aim at the oscillation and misjudgment of traditional perturbation observation method, an improved perturbation observation method comparing to the next moment power is proposed, combining with BOOST step-up circuit to realize the maximum power tracking. To counter the harmonic pollution problem in photovoltaic grid power generation system, the deadbeat control scheme in fundamental wave synchronous frequency rotating coordinate system of power grid is presented. A parameter optimization scheme based on positive feedback of active frequency shift island detection to solve the problems like the nondetection zone due to the import of disturbance in traditional island detection method is proposed. Finally, the results in simulation environment by MATLAB/Simulink simulation and experiment environment verify the validity and superiority of the proposed scheme.

Analyse the Field-Circuit Coupling Model of the Switching Converters

Based on the finite element methods of ANSYS software, field-circuit coupling methods are generally used in modeling and analsysing switch converter circuit of Simple step-up Boost circuit. Compare the Simulation results with ANSYS and MATLAB/simulink circumstances, Field-circuit coupling model is correct, through real calculation was tested and verified. Combination with authors preceding paper, there are indications that ANSYS software applies to electromagnetic field analyse electronic device and circuit. Above research works make a foundation for further studying electromagnetic field analyse problem working personnel and scientific research personnel are of application worthiness.

A Family of Three-Switch Three-State Single-Phase $Z$-Source Inverters

This paper proposes a new family of three-switch three-state single-phase Z-source inverters (TSTS-ZSIs) that can be classified into two groups, boost-based TSTS-ZSI and buck–boost-based TSTS-ZSI, according to the step-up circuit. All of the topologies have the merits of buck–boost capability and low voltage stress, and some of them have the feature of dual grounding. In addition, the step-up in dc side and inversion in ac side is completely decoupled in the proposed topologies. In terms of a linear voltage gain, the conventional linear control methods can be used, which makes the control system very simple. The operating principles of the two types of topologies are described, respectively, and the comprehensive comparison between them is provided. Finally, the theoretical analysis and comparison of the proposed topologies are verified by the simulation and experimental results.

High Step-up Boost Converter Integrated With a Transformer-Assisted Auxiliary Circuit Employing Quasi-Resonant Operation

Stacking an auxiliary step-up circuit on top of a boost converter is one of the most attractive structures for nonisolated high step-up applications. In this paper, in order to avoid the large input current ripple of coupled-inductor-based circuits, an auxiliary step-up circuit is integrated via an additional transformer and its balancing capacitor. A voltage-doubler is adopted as an auxiliary step-up circuit, which is inherently suitable for high-voltage applications due to its simple structure and low-voltage stress. Moreover, the transformer leakage inductor and the balancing capacitor constitute a resonant tank so that the quasi-resonant operation makes the current sinusoidal. As a result, a reduced switch turn-off loss and reverse recovery of the diode can be expected. The proposed converter is verified with a 24 V input, 160 W - 200 V output prototype.

Application of Thyristor AC Voltage Regulation Technology in ICP Spectrum Excitation Source

SCM control technology be applied to inductively coupled plasma excitation source in this paper. Through controlling thyristor trigger angle control AC voltage regulation, the go through step-up circuit to achieve output power continuously adjustable. It introduces construction and work principle. Grating spectrograph is co-operated with thyristor AC voltage ICP excitation source for performance tested. By means of Ar355.431nm tested power stability≤0.5%. Testing Fe, Cu, Au and other elements shows that the detection limit is 10-9g/ml, precision relative standard deviation RSD≤ 3％. Results show that this voltage regulation technology is stable, reduces the instrument’s size and operates conveniently. It is suitable for ICP excitation source in spectroscopic analysis.

Electronic Equipment Proposal to Improve the Photovoltaic Systems Efficiency

This paper reports a new technique proposal to improve the photovoltaic systems. It was made to design and implement an electronic system that will detect, capture, and transfer the maximum power of the photovoltaic (PV) panel to optimize the supplied power of a solar panel. The electronic system works on base technical proposal of electrical sweeping of electric characteristics using capacitive impedance. The maximum power is transformed and the solar panel energy is sent to an automotive battery. This electronic system reduces the energy lost originated when the solar radiation level decreases or the PV panel temperature is increased. This electronic system tracks, captures, and stores the PV module’s maximum power into a capacitor. After, a higher voltage level step-up circuit was designed to increase the voltage of the PV module’s maximum power and then its current can be sent to a battery. The experimental results show that the developed electronic system has 95% efficiency. The measurement was made to 50 W, the electronic system works rightly with solar radiation rate from 100 to 1,000 W m − 2 and the PV panel temperature rate changed from 1 to 75°C. The main advantage of this electronic system compared with conventional methods is the elimination of microprocessors, computers, and sophisticated numerical approximations, and it does not need any small electrical signals to track the maximum power. The proposed method is simple, fast, and it is also cheaper.

Design of the Thermoelectric Generator

Thermoelectric Generator is a device using the widespread natural temperature to generate electricity. On the basis of investigations and experiments, this paper fully expounded thermoelectric generator’s significance, system block diagram, circuits, operational principle, application foregrounds and etc. Semiconductor thermoelectric module and the controller compose the thermoelectric generator, semiconductor thermoelectric power modules change heat energy into electric energy, the electric energy is stored in the controller's battery by the charging circuit. The controller has many functions such as current limiting, under voltage and other functions. At the same time, we had also designed the step-up circuit, in this way, the thermoelectric generator can output higher voltage. The experiment results and application show the thermoelectric generator has good performance and powerful function, it is worth spreading.