Prototype Circuit Research Articles

Statistical analysis of radiofrequency energy harvester with bandpass filter for ultra‐low power applications

AbstractNowadays, radiofrequency (RF) is a vital component of harvesting RF energy from the ambient environment to power ultra‐low‐power applications in wireless communication. This article presents an RF energy harvesting system for a frequency range of (0.58–3 GHz) to harvest RF energy from the ambient source. The system's design consists of four major modules: a coplanar waveguide antenna (CPW), a bandpass filter (BF), an L‐type impedance matching network, and a four‐stage Villard voltage multiplier (VM) circuit. First, A CPW antenna is designed suitably to harvest RF energy from GSM 900/1800, 3G, and Wi‐Fi frequency bands. Next, a BF is designed and simulated in Agilent advanced design system software for the same frequency range to attenuate the RF signals that are not in this specific frequency range. Then, an RF power conditioning circuit prototype comprising an L‐type impedance matching network and a four‐stage Villard VM circuit was integrated and fabricated on an FR4 substrate. The four‐stage rectifier circuit is designed to convert the RF signal into DC output voltage and maximize the output voltage. The performance of the RF energy harvesting system is validated through simulation and measured results. All the RF energy harvesting system elements have been connected, and the prototype is tested at various indoor and outdoor locations of Sri Sivasubramaniya College of Engineering, Chennai, India. It is observed that the prototype system can harvest energy from input power levels as low as −30 dBm. The simulated results of the RF energy harvesting system achieve an output voltage of 2.5 V with a maximum efficiency of 62.5%. The harvested output voltage at a distance of 100 m from the RF cell tower at the indoor location is 59.5 mV and at the outdoor location 271.6 mV. The harvested output voltage is used to energies the ultra‐low‐power applications. Finally, the performance of the RF energy harvesting system is analyzed by statistical techniques. The two types of analysis are Taguchi's method and analysis of variance. The RF energy harvester impact factors are VM and BF. A statistical test (P) is used to determine the significant factors on the RF output voltage.

A silicon carbide high gain differential amplifier for extreme temperature applications

In this paper, a high temperature, high gain differential amplifier based on a custom-built silicon carbide (SiC) N-channel junction field effect transistor (JFET) only, without using complementary P-channel devices is proposed. The operation principle of this active load differential amplifier is discussed, and the expression of the differential gain is derived. A prototype circuit is fabricated using thick film process on an alumina substrate and tested from room temperature up to 500 °C to demonstrate the high temperature capability of the proposed differential amplifier. The differential gain of 50.8 dB is achieved with 58.6 dB common-mode rejection ratio (CMRR) and 9.1 MHz gain bandwidth product (GBW) at 500 °C. Excellent linearity and low output impedance of the proposed differential amplifier are also demonstrated at various temperatures. The proposed SiC JFET high gain differential amplifier can serve as a fundamental building block of the signal conditioning circuitry to be integrated with the sensing element for extreme environment applications.

Fully Soft Switched Interleaved High Step-Up/Down Bidirectional Converter With no Pulsating Current at Low Voltage Source

In this article, a fully soft switched interleaved bidirectional buck/boost converter with high voltage conversion ratio (VCR) and no pulsating current at low voltage source is proposed. Winding cross-coupled inductors technique is employed in order to increase VCR and mitigate current ripple at low voltage side. Moreover, soft switching conditions for all semiconductor devices are provided and the leakage inductances energy of coupled inductors are absorbed in both high step-up/down operating modes. Furthermore, the reverse recovery problem of all diodes is removed due to zero current switching turn <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> . All the mentioned advantages are achieved for a bidirectional converter with two interleaved phases in both high step-up/down operating modes by only one clamp circuit consisting of a clamp capacitor and two active switches. Also, the body diodes of the main switches are utilized as the main diodes to reduce the element count. The converter performance is validated by theoretical analysis and an 800 W prototype circuit in both operating modes.

A DC Arc Fault Detection Method Based on AR Model for Photovoltaic Systems

DC arc faults are dangerous to photovoltaic (PV) systems and can cause serious electric fire hazards and property damage. Because the PV inverter works in a high−frequency pulse width modulation (PWM) control mode, the arc fault detection is prone to nuisance tripping due to PV inverter noises. An arc fault detection method based on the autoregressive (AR) model is proposed. A test platform collects the database of this research according to the UL1699B standard, in which three different types of PV inverters are taken into consideration to make it more generalized. The arc current can be considered a nonstationary random signal while the noise of the PV inverter is not. According to the difference in randomness features between an arc and the noise, a detection method based on the AR model is proposed. The Burg algorithm is used to determine model coefficients, while the Akaike Information Criterion (AIC) is applied to explore the best order of the proposed model. The correlation coefficient difference of the model coefficients plays a role as a criterion to identify if there is an arc fault. Moreover, a prototype circuit based on the TMS320F28033 MCU is built for algorithm verification. Test results show that the proposed algorithm can identify an arc fault without a false positive under different PV inverter conditions. The fault clearing time is between 60 ms to 80 ms, which can meet the requirement of 200 ms specified by the standard.

A 6.78-MHz Burst-Mode Controlled Inductive Wireless Power Transfer System for Biomedical Implants With Back-Channel Communication Eliminated Using Transmitter Q-Factor Detection

This article presents an analysis and design of high-efficiency, 6.78-MHz burst-mode controlled inductive wireless power transfer system (WPT) with no back-channel communication between a transmitter (TX) and a receiver (RX). Power is transmitted in bursts between the TX and the RX, and the duty cycle of the burst is controlled through load modulation to control power flow between the TX and the RX. Extra back-channel traditionally used for TX–RX communication to control power flow is avoided by using inherent load modulation properties of the WPT circuit. It is demonstrated that the quality factor of the TX can be detected to eliminate the back-channel communication. Furthermore, only an extra switch is added in the RX power stage in series with the load to regulate the output voltage. The proposed WPT circuit can regulate output voltage against distance variation of up to 3 cm using 3-cm-diameter TX and RX coils and a load variation from full load to no load. A 330-mW prototype circuit for use in medical implants is designed, built, and tested. The proposed research advances the state-of-the-art WPT systems for use in resource-constrained biomedical implants.

Development of Solar Energy Lamp Using Arduino Uno

This study aims to design an electronic system from solar energy lamps using Arduino Uno and then implement it into a prototype circuit. This solar energy lighting system supports the green energy ecosystem in the implementation of solar cells in the design of cost-effective electronic systems. This automatic solar energy lamp system consists of solar panels and batteries as inputs, LDR and voltage sensors as references and sensors, Arduino Uno and relays as controllers, and LCD and LED lights as output circuits. The implementation results show that solar energy lamps using Arduino Uno can function properly. The solar energy stored in the battery can be used automatically as lighting at night without using electricity from PLN. It can automate the light in the room, eliminating the need to turn them off and on manually.

An Active Clamp Flyback Converter With High Precision Primary-Side Regulation Strategy

The active clamp flyback (ACF) converter has been widely adopted because of the feature of isolation, soft-switching, and high conversion efficiency. On the other hand, due to the characteristic of the circuit cost reduction and the fast control response, the primary-side regulation (PSR) has become a popular control method for isolated power converters. However, high precision PSR strategies for ACF converters are not exposed. Therefore, the aim of this article is to propose a high precision PSR strategy for the ACF converter. Relations between the primary-side current and the secondary-side current are analyzed and derived. Both of the continuous conduction mode operation and the discontinuous conduction mode operation will be considered. The output voltage control mode or the output current control mode can be selected via the proposed strategy. In addition, a secondary-side losses compensation (SSLC) strategy is developed to deal with the non-ideal circuit characteristics as well as to enhance the control accuracy. Operational principles and thorough mathematical derivations will also be revealed. Finally, both simulation and experimental results obtained from a 100 W prototype circuit demonstrate the performance and feasibility of the proposed PSR and SSLC strategy. Validations show that the control accuracy of the output voltage and the output current are 98.54% and 98.42%, respectively.

A Single-Input Dual-Output DC-DC Converter for Powertrain of PEM Fuel Cell Vehicle

Multi-output converter plays a vital role in portable electronic and electric vehicle (EV) applications. In this regard, a new single-input dual output (SIDO) converter is proposed in this paper. Most of the single-input dual-output converter configurations presented by various researchers in the domain of multi-output converters function under particular assumptions about operational duty cycle and inductor current.Also, the issue of crossregulation is still prevalent while operating the loads in many SIDO converters.The proposed configuration generates two output voltages in boost and buck-boost modes without any constraints on the duty ratioor inductor currents. In addition, it doesn't encounter cross-regulation problems; subsequently, the output voltage V01 (V02) is not influenced by load changes in i02 (i01). To verify the feasibility and effectiveness of the proposed configuration, a 200 W prototype circuit is developed; simulation and experimental results are validated.

New Class of Power Converter for Performing the Multiple Operations in a Single Converter: Universal Power Converter

Universal power converters (UPCs) have aroused significant attention in performing multiple operations in a single power converter. Furthermore, they contribute to economic operation and improved system performance. In this work, a new configuration of the universal power converter (UPC) was proposed by using a simple switching arrangement. It can perform different modes of operations, such as AC–DC, DC–DC, DC–AC, AC–AC, and cyclo-converter operations. In DC–DC conversion, the proposed configuration can perform buck mode, boost mode, and buck–boost mode of operations. Moreover, in DC–AC conversion, it gives better total harmonic distortion (THD). The effectiveness of the proposed configuration was verified by an extensive simulation, using MATLAB/Simulink environment. A low-power prototype circuit was designed to test the viability of the proposed circuit configuration and validated with simulation results.

Stability Boundary and Enhanced Solution of Dual-Mode Based Micro Gyroscope Mode Matching Technology.

During in-run mode matching under a dual-mode gyro scheme, the stability of the closed-loop control system has a boundary. This phenomenon will lead to the failure of the in-run frequency split calibration scheme when the initial mode mismatch is too severe to exceed the stability boundary. This paper gives a detailed analysis of this stability boundary through simulations and experiments. Results show that the length of the stable region will be affected by the resonant frequency and the Q value. High resonant frequency and low Q value will widen the stable region, but also reduce the sensitivity and rapidity of the calibration. In order to remove the limitation of the stability boundary while applying the in-run frequency split calibration under dual-mode architecture, this paper proposes an enhanced solution that combines both the dual-mode scheme and technology of mode switching. The application of mode switching achieves a pre-calibration of frequency split before the normal gyro operation. This solution is implemented in engineering on a hybrid gyro interface circuit prototype with single-mode and dual-mode. Validation experiments confirmed the effectiveness of this solution.

A single‐switch high step‐up Zero Current Switching DC‐DC converter based on three‐winding coupled inductor and voltage multiplier cells with quasi resonant operation

AbstractThis paper presents a nonisolated high step‐up soft switching DC/DC converter with continuous input and output energy, low input current ripple, and low voltage stress of semiconductors. In this topology, passive clamping circuits are used not only to recycle leakage energy but also to successfully alleviate voltage spikes on the active MOSFET. The leakage inductor, on the other hand, solves the output diode's reverse recovery problem effectively. Furthermore, output capacitors are connected in series to supply the output load, resulting in a smaller output capacitor volume. The suggested topology's operational theory, as well as steady‐state analyses, is thoroughly explored. The proposed topology's voltage gain and switch stress are then compared with that of some high‐gain topologies. After this, a prototype circuit with a 20 V input voltage, 340 V output voltage, and 200 W output power is designed to test the proposed topology's accuracy.

High step‐up active switched coupled inductor DC‐DC converter with voltage multiplier

AbstractHigh step‐up DC‐DC converters are commonly used in new energy applications such as DC microgrid, photovoltaic cell, and fuel cell. Thus, this article introduces a new nonisolated high step‐up DC‐DC converter based on active switched coupled inductor with a voltage multiplier cell. The proposed converter presents low current and voltage stress across the switches owing of the dual active switches structure. Besides that, by the voltage multiplier cell (one diode and one capacitor), the voltage gain of proposed converter is increased. In addition, it can be highlighted that the proposed converter has low component count, simplicity of operation in continuous and discontinuous conduction mode, and energy stored in the leakage inductor that is recycled in the capacitor of voltage multiplier cell. This article discussed the principle of operation, the ideal and nonideal voltage gain, external characteristic, voltage and current stress, design guidelines, and performance comparison with previous high step‐up converters. Finally, a prototype circuit with input power 300 W, input voltage 30 V, and output voltage 400 V was built in the laboratory to verify the theoretical evaluation, and the maximum achieved efficiency was 95.35% at nominal power 300 W.

Simplified configuration with reduced part count and improved total harmonic distortion for DC–AC conversion

The quality of power generation from various energy sources is essential for industrial and household applications. To achieve the quality of power by minimizing the total harmonic distortion (THD) through multi-level inverters (MLIs) is an attractive solution. MLIs have tremendous performance against %THD and electromagnetic interference (EMI) issues compared with the classical two-level inverters. However, MLIs have more device count and intricacy of the circuitry for further reducing the THD, which increases the complexity and cost of the converter. In the paper, a new approach is suggested for reducing the THD through the proposed inverter with a comparatively lower quantity of power electronic components and less control complexity. The proposed inverter is tested in the simulation environment and on an experimental test using low power (150 W) prototype circuit.

Zero-Voltage Switching Full-Bridge Converter With Reduced Filter Requirement and Wide ZVS Range for Variable Output Application

In this article, a novel zero-voltage switching (ZVS) full-bridge converter is proposed to overcome the disadvantages of traditional phase-shifted full-bridge (PSFB) converter. In the proposed converter, a half-bridge (HB) converter with center-tap rectifier (CTR) is integrated into the traditional PSFB converter by sharing the lagging-leg switches and output filter. The HB converter operates with full duty cycle to ensure continuous energy transmission and the output voltage is regulated by adjusting the phase-shifted time of full-bridge (FB) converter. The proposed converter has many advantages such as reduced filter requirement, wide ZVS range and low primary circulating current. In addition, the rectifier in the proposed converter is composed of a full-bridge rectifier section and a CTR section. This feature makes the proposed converter well appropriate for the medium output voltage applications. Key operation principle and characteristics are fully discussed in this article. The effectiveness of proposed converter is verified using a 1.2 kW prototype circuit with 280 V input voltage and 60–120 V output voltage.

Resonant Asymmetrical Half-Bridge Flyback Converter

The active clamp flyback (ACF) converter is gradually becoming popular in the application field of low or medium output power range due to its advantage of soft switching and high conversion efficiency. An asymmetric half-bridge (AHB) flyback converter has been proposed in previous studies. The main advantages of the AHB flyback are the same number of components as the ACF converter and the soft switching technique. In this paper, an AHB flyback converter with constant off-time (COT) plus pulse frequency modulation (PFM) is proposed, so that the resonant time is not affected by the input voltage and load, and can achieve a wide range of zero voltage switching (ZVS) operating range. Compared to pulse width modulation (PWM), the PFM control with COT can make the system more stable. Finally, a prototype circuit with a specification input of 48 V to an output of 2.5 V/8 A is made for verification.

Modular DC‐DC converter with reduced current ripple and low voltage stress suitable for high voltage applications

AbstractIn this paper, a couple inductor‐based dc‐dc boost converter with extensible capability is presented. In the proposed converter, attaching extensions to input section alleviates input current ripple. Furthermore, the current sharing performance between different phases operates beneficially by expanding optimized boost converters, especially when a partial inequality exists among different switches' duty cycles and leakage inductances. The voltage conversion ratio of the proposed converter is also additionally optimized by a series of VMR's output capacitors. Meanwhile, not only the voltage stress upon the main switches is decreased but also the all switches are managed to be turned on with zero current switching technique. The voltage spikes across MOSFETs are eliminated by using the recycling energy of leakage inductances on the clamp capacitor. The topology of the proposed converter, steady‐state analysis, and design procedure is presented to indicate the merits of the suggested converter. A prototype circuit with a three‐phase interleaved boost converter, two number of diode‐capacitor in each VMR, and output power 660 W and 40–800 V conversion ratio is experimented to corroborate the validity of the presented structure.

Caution Influences Avoidance and Approach Behaviors Differently.

While conflict between incompatible goals has well-known effects on actions, in many situations the same action may produce harmful or beneficial consequences during different periods in a nonconflicting manner, e.g., crossing the street during a red or green light. To avoid harm, subjects must be cautious to inhibit the action specifically when it is punished, as in passive avoidance, but act when it is beneficial, as in active avoidance or active approach. In mice of both sexes performing a signaled action to avoid harm or obtain reward, we found that addition of a new rule that punishes the action when it occurs unsignaled delays the timing of the signaled action in an apparent sign of increased caution. Caution depended on task signaling, contingency, and reinforcement type. Interestingly, caution became persistent when the signaled action was avoidance motivated by danger but was only transient when it was approach motivated by reward. Although caution is represented by the activity of neurons in the midbrain, it developed independent of frontal cortex or basal ganglia output circuits. These results indicate that caution disrupts actions in different ways depending on the motivational state and may develop from unforeseen brain circuits.SIGNIFICANCE STATEMENT Actions, such as crossing the street at a light, can have benefits during one light signal (getting somewhere) but can be harmful during a different signal (being run over). Humans must be cautious to cross the street during the period marked by the appropriate signal. In mice performing a signaled action to avoid harm or obtain reward, we found that addition of a new rule that punishes the action when it occurs unsignaled, delays the timing of the signaled action in an apparent sign of increased caution. Caution became persistent when the signaled action was motivated by danger, but not when it was motivated by reward. Moreover, the development of caution did not depend on prototypical frontal cortex circuits.

Synthesis Design of Wideband Phase Shifters Using Coupled-Line Structure

In this letter, a new class of wideband phase shifters using parallel-coupled-line resonators is proposed and developed. The proposed phase shifter consists of two distinctive branches: a parallel-coupled-line filter and a reference line section. Compared with its conventional counterpart, this phase shifter has a few advantageous features such as simple geometry, small size, wide bandwidth, small phase deviation, and easy adjustment in phase shift. Then, a synthesis design method for a wideband phase shifter is described. For verification, its prototype circuit with a phase shift of 180&#x00B0; is finally designed, fabricated, and measured. Simulated and measured results are found in good agreement.

Microwave Metasurface Cloaking for Freestanding Objects

Since the introduction of transformation optics and experimental demonstration using microwave metamaterials in 2006, a variety of electromagnetic invisibility cloaking techniques and physical realizations based on coordinate transformations, scattering cancellation, and control of reflected and transmitted waves have been reported from microwaves to visible. However, existing cloaking methodologies face challenges in reducing cloak thicknesses, concealing large volumes, and cloaking free-standing objects. Here, we design, fabricate, and experimentally validate a unidirectional, single-layer printed metasurface cloak for free-standing cylindrical objects in the microwave regime. Based on a spatially modulated reactance surface, the printed metasurface converts an incident plane wave on the lit side into a surface wave, which carries power to the shadow side before reconstructing the incident wave behind the object. Using a subwavelength-thin printed circuit prototype, the cloaking function is experimentally confirmed, demonstrating a thin, passive cloak that conceals a large, free-standing object.

Design of balanced UWB BPF based on quint‐mode slotline resonator

In this paper, a quint-mode slotline resonator (QMSR) is analyzed and designed. The proposed resonator has similar performances to those of the conventional microstrip multimode resonator, while it is located at the bottom ground layer. To the best of our knowledge, this is the first time that QMSR is proposed. By properly adjusting the dimensions of the proposed QMSR, quasi-independent control of the five resonant frequencies is realized, thereby an ultrawideband (UWB) differential-mode (DM) transmission passband can be obtained. By employing balanced microstrip/slotline transition structure, a high and wideband common-mode (CM) suppression can also be realized, which is independent of the DM responses. Thereby, only the DM performances need to be considered, which simplify the design procedure greatly. In addition, one notched band is achieved to suppress the special electromagnetic interference. To validate the design concept, one prototype circuit of the proposed balanced UWB bandpass filter is implemented following the given design procedure. Good agreement between the measurement and simulation results can be observed.