Reference Voltage Research Articles

Nonlinear control of two-stage single-phase standalone photovoltaic system.

This paper presents a single-phase Photovoltaic (PV) inverter with its superior and robust control in a standalone mode. Initially, modeling and layout of the Buck-Boost DC-DC converter by adopting a non-linear Robust Integral Back-stepping controller (RIBSC) is provided. The controller makes use of a reference voltage generated through the regression plane so that the operating point corresponding to the maximum power point (MPP) could be achieved through the converter under changing climatic conditions. The other main purpose of the Buck-Boost converter is to act like a transformer and produce an increased voltage at the inverter input whenever desired. By not using a transformer makes the circuit size more compact and cost-effective. The proposed RIBSC is applied to an H-bridge inverter with an LC filter to produce the sinusoidal wave in the presence of variations in the output to minimize the difference between the output voltage and the reference voltage. Lyapunov stability criterion has been used to verify the stability and finite-time convergence of the overall system. The overall system is simulated in MATLAB/Simulink to test the system performance with different loads, varying climatic conditions and inverter reference voltages. The proposed methodology is compared with a back-stepping controller and Proportional Integral Derivative (PID) controller under rapidly varying climatic conditions. Results demonstrated that the proposed technique yielded a tracking time of 0.01s, a total harmonic distortion of 9.71% and a root means square error of 0.3998 in the case of resistive load thus showing superior control performance compared to the state-of-the-art control techniques.

An approach for designing leakage compensated voltage reference circuit

ABSTRACT In this paper, the design of CMOS-based and recyclic folded cascode (RFC)-based voltage reference circuits is presented. Further inherent leakage compensation technique using diode connected MOSFET is introduced, which results in the compensation of high-temperature leakage current and a reduction in consumed power. Moreover, current mirror-induced mismatch and supply dependency reduces. Furthermore, temperature range and power supply rejection ratio (PSRR) improves. Later, comparison between the two configurations, i.e. with and without leakage compensation, has been presented. The minimum value of the achieved temperature coefficient on applying leakage compensation is 4.2 ppm/ºC for the proposed RFC op-amp-based voltage reference circuit with improved temperature range by 40°C. The obtained value of PSRR is −88.2 dB at 10 Hz, −66.8 dB for 1 KHz and −61.6 dB for 1 MHz frequency, with the line sensitivity of 0.031%/V and the variation of 1.69 mV for an entire operating temperature range. All the simulation results are obtained at 0.7 V supply voltage in 180 nm SCL technology.

Passivity-based Rieman Liouville fractional order sliding mode control of three phase inverter in a grid-connected photovoltaic system.

Photovoltaic (PV) system parameters are always non-linear due to variable environmental conditions. The Maximum power point tracking (MPPT) is difficult under multiple uncertainties, disruptions and the occurrence of time-varying stochastic conditions. Therefore, Passivity based Fractional order Sliding-Mode controller (PBSMC) is proposed to examine and develop a storage function in error tracking for PV power and direct voltage in this research work. A unique sliding surface for Fractional Order Sliding Mode Control (FOSMC) framework is proposed and its stability and finite time convergence is proved by implementing Lyapunov stability method. An additional input of sliding mode control (SMC) is also added to a passive system to boost the controller performance by removing the rapid uncertainties and disturbances. Therefore, PBSMC, along with globally consistent control efficiency under varying operating conditions is implemented with enhanced system damping and substantial robustness. The novelty of the proposed technique lies in a unique sliding surface for FOSMC framework based on Riemann Liouville (R-L) fractional calculus. Results have shown that the proposed control technique reduces the tracking error in PV output power, under variable irradiance conditions, by 81%, compared to fractional order proportional integral derivative (FOPID) controller. It is reduced by 39%, when compared to passivity based control (PBC) and 28%, when compared to passivity based FOPID (EPBFOPID). The proposed technique led to the least total harmonic distortion in the grid side voltage and current. The tracking time of PV output power is 0.025 seconds in PBSMC under varying solar irradiance, however FOPID, PBC, EPBFOPID, have failed to converge fully. Similarly the dc link voltage has tracked the reference voltage in 0.05 seconds however the rest of the methods either could not converge, or converged after significant amount of time. During solar irradiance and temperature change, the photovoltaic output power has converged in 0.018 seconds using PBSMC, however remaining methods failed to converge or track fully and the dc link voltage has minimum tracking error due to PBSMC as compared to the other methods. Furthermore, the photovoltaic output power converges to the reference power in 0.1 seconds in power grid voltage drop, whereas other methods failed to converge fully. In addition power is also injected from the PV inverter into the grid at unity power factor.

An improved state‐space average model of the ultra‐high voltage inverter based on wavelet decomposition and reconstruction

SummaryUltra‐high voltage inverters are widely used as grid‐connected devices in new energy grids, and the state‐space average model is the most practical modeling method for the inverter. However, the accuracy of this modeling method is significantly reduced because it ignores the high‐frequency switching process, which contains overshoot voltage and other factors that affect system stability. Moreover, the amplitude of the overshoot voltage in the ultra‐high voltage inverter will be huge, which may lead to the damage to switching devices, circuit overheating, and even the collapse of the system. Therefore, the wavelet decomposition and reconstruction methods are used in this paper to extract the transient characteristics of the inverter and integrate them into the state‐space average model. Compared with the traditional state‐space average model, the improved model method can obtain a more accurate overshoot voltage peak value with the same simulation step size. Then, it can provide a more precise reference for the withstand voltage in the device selection of a high voltage level system. The single‐phase full‐bridge inverter is taken as an example to illustrate the construction process based on the wavelet decomposition and reconstruction method. Finally, the simulation waveform is verified to be in good agreement with the experiment.

Extension of Operating Range in Hybrid Cascaded H-Bridge Inverters with Capacitor Voltage Balancing Capability

In this article, a generalized control scheme is proposed to extend the operating range of three-phase hybrid cascaded H-bridge (HCHB) inverters into various voltage levels without necessitating alterations to the core structure or the integration of additional H-bridge submodules. This study addresses a critical challenge related to capacitor voltage drift at various modulation indices and power factors, which is a serious impediment to various applications. To overcome this challenge, a novel balancing control scheme has been developed based on the injection of two independent offset voltages to simultaneously control the DC-link and flying capacitors. A distinctive aspect of the proposed technique involves adjusting the common reference voltage to attain the nearest level in the same cluster, thereby mitigating the insufficiency of redundant switching states. The effectiveness of the proposed technique to regulate the capacitor voltages at various operating conditions has been verified through simulation and experimental results.

Reconfiguring a Plane-Parallel Transmission Ionization Chamber to Extend the Operating Range into the Ultra-High Dose-per-pulse Regime.

This study aims to investigate the feasibility of enhancing the charge collection efficiency (CCE) of a transmission chamber by reconfiguring its design and operation. The goal was to extend the range of dose-per-pulse (DPP) values with no or minimal recombination effects up to the ultra-high dose rate (UHDR) regime. The response of two transmission chambers, with electrode distance of 1 mm and 0.6 mm, respectively, was investigated as a function of applied voltage. The chambers were mounted one-by-one in the electron applicator of a 10 MeV FLASH-modified clinical linear accelerator. The chamber signals were measured as a function of nominal DPP, which was determined at the depth of dose maximum using EBT-XD film in solid water and ranged from 0.6 mGy per pulse to 0.9 Gy per pulse, for both the standard voltage of 320 V and the highest possible safe voltage of 1,200 V. The CCE was calculated and fitted with an empirical logistic function that incorporated the electrode distance and the chamber voltage. The CCE decreased with increased DPP. The CCE at the highest achievable DPP was 24% (36%) at 320 V and 51% (82%) at 1,200 V, for chambers with 1 mm (0.6 mm) electrode distance. For the combination of 1,200 V- and 0.6-mm electrode distance, the CCE was ∼100% for average dose rate up to 70 Gy/s at the depth of dose maximum in the phantom at a source-to-surface distance of 100 cm. Our findings indicate that minor modifications to a plane-parallel transmission chamber can substantially enhance the CCE and extending the chamber's operating range to the UHDR regime. This supports the potential of using transmission chamber-based monitoring solutions for UHDR beams, which could facilitate the delivery of UHDR treatments using an approach similar to conventional clinical delivery.

Constant Power Load Stabilization With Fast Transient Boundary Control for DAB-Converters-Based Electric Drive Systems

Due to the negative incremental impedance of constant power loads (CPLs), many undesirable issues such as the oscillations or even possible collapse of the main dc bus voltage may occur, which may significantly degrade the system stability of Electrical Vehicles (EVs). This paper presents a natural-switching-surface (NSS) fast-transient-boundary-control (FTBC) based stabilization solution for EVs with dual-active-bridge (DAB) converters as the main power interface. Based on the mathematical models of multiple natural switching surfaces (NSS) and characteristics of CPL, the proposed FTBC control can achieve stable operation of DAB converters feeding CPLs and fast dynamic response irrespective operating stages such as the startup, sudden voltage and power reference changing conditions. Compared with other strategies such as load shedding, the proposed FTBC has no additional requirements for hardware, which is cost-effective. The analytical derivation of the proposed algorithm under the CPL condition is presented together with simulation and experimental evaluations, which validate that the proposed FTBC is capable of achieving 2 times faster start-up process and at least 33% dynamic response improvement compared with proportional integrator (PI) closed-loop control while eliminating the dc-bias current and guaranteeing the CPL stability by regulating the dynamic trajectories of DAB converters in the geometric domain.

Influence of generator parameters on cutting width during WEDM process

The primary objective of this paper is to rigorously analyse the influence of selected parameters on the cut width in the context of Wire Electric Discharge Machining (WEDM). The parameters under investigation, each varied at different levels, include pulse width, servo reference mean voltage, time interval between two pulses, discharge frequency, and wire feed speed. As the workpiece material, sintered carbide K10 was used. Data for the response variable, cut width, was meticulously collected using two high-precision instruments: the Zoller Genius 3s and the Alicona InfiniteFocusSL. Among the parameters studied, the mean reference voltage emerged as the most influential variable. It holds a commanding lead with a percentage contribution of as much as 82.4 %, making it nearly 15 times more impactful than the second most influential parameter, which is pulse width. At its lowest setting, or first level, the mean reference voltage results in a record low cut width. Conversely, at its highest setting, or third level, it leads to a record high cut width. This comprehensive analysis not only quantifies the relative importance of each parameter but also provides valuable insights into the optimal settings for achieving desired cut widths. The findings have significant implications for improving the efficiency and precision of WEDM processes.

An Improved Dual-Gate Compact Model for Carbon Nanotube Field Effect Transistors with a Back-Gate Effect and Circuit Implementation

Compared to single-gate CNTFET, dual-gate structures have better electrostatic control over nanowire conductive channels. However, currently, there is insufficient research on the back-gate effect in a compact model of dual-gate CNTFET. This paper presents an improved dual-gate carbon nanotube field effect transistor (CNTFET) compact model. The functional relationship between the back-gate voltage (Vbg) and threshold voltage (Vth) is derived. And a voltage reference regulation mechanism is adopted so that the back-gate effect can be accurately reflected in the DC transfer characteristics. The influence of gate voltage and drain voltage on transmission probability is analyzed. Meanwhile, the drain current is optimized by modifying the mobility equation. This compact model is built based on Verilog-A hardware language and supports the Hspice simulation tool. Within the supply voltage of 2 V, the simulation results of the proposed compact model are in good agreement with the measurement results. Finally, based on the compact model, an operational amplifier is designed to verify its correctness and feasibility in analog integrated circuits. When the power supply voltage is 1.8 V, and the load capacitance is 2 pF, the gain is 11.8 dB, and the unit-gain-bandwidth (UGB) is 214 kHz, which proves the efficiency of our compact model.

Sub-μW Auto-Calibration Bandgap Voltage Reference With 1σ Inaccuracy of ± 0.12% Within − 40°C to 120°C

Sub-μW Auto-Calibration Bandgap Voltage Reference With 1σ Inaccuracy of ± 0.12% Within − 40°C to 120°C

Transfer operation ride though control strategy of the aircraft power supply system with lithium battery energy storage

The aircraft power supply system turns towards multi-source, and transfer operation will likely happen during flight missions and fault conditions. The transfer may lead to voltage interruptions and current surges, adversely affecting power quality. This paper proposes incorporating a lithium battery energy storage system (ESS) into the aircraft high-voltage direct current (HVDC) power system. The ESS employs a voltage control model with a lower voltage reference base, facilitating a smooth transfer operation during power interruptions. This approach reduces voltage fluctuations in the power supply system, enhances power quality, and enables seamless power transfer during the transfer operation.

Research on three-level PWM Rectifier without grid voltage sensor

Traditional three-level PWM rectification technology usually uses voltage sensors to sample the grid voltage, and then obtains the angle information of the voltage vector through a phase-locked loop, thereby achieving the d/q axis control function of voltage and current. However, the use of voltage sensors not only increases system costs, but also increases system volume and debugging difficulty. In addition, when the voltage sensor is damaged, it can cause system shutdown and affect system reliability. After analyzing the three-level control method of PWM rectifiers, a sensorless control strategy for grid voltage based on sliding mode observer method is proposed. By using the sliding mode observer method to estimate the amplitude and phase of the power grid voltage at the voltage and current values of each PWM cycle, a phase-locked loop is used to determine the position of its voltage vector. The simulation results all demonstrate that the proposed method can accurately and effectively estimate the voltage vector angle of the power grid, and ensure that the output of the rectification system meets the standard voltage waveform.

PERENCANAAN INSTALASI LISTRIK GEDUNG WAREHOUSE PT. XYZ SEMARANG JAWA TENGAH

Warehouse Building PT. XYZ at Semarang Central Java is a building place for keeping logistics owned by the company with a large area. There is also buildings' support in it so that required system installation suitable electricity with applicable standards such as PUIL 2011 and other standards in the field of electricity. The main electricity supply uses a source from PLN, and the generator is set as a backup source when electricity from PLN is dead. Plan installation at PT. XYZ Warehouse building, namely the installation of lighting, socket installation, air conditioning installation, electronics installation, installation of rolling door, installation of local government fire pump, and installation of clean water transfer pump. There are LVMDP panels, SDP panels, and subpanels as supply power for the installation that will be installed. Breaker rating selection power and dimensions cable delivery person who will use will affect on reliability network installation. Calculation of CRC will influence election breaker power, cable diameter selection delivery, and drop the voltage to happen on the network installation. The calculation was conducted manually. With more formerly collected load data equipment electricity at PT. XYZ Semarang and classification distribution system split panel installation, SDP panel, and LVMDP panel. The total load installed on the PT. XYZ Semarang Warehouse building is known as 318,406 VA or 318 kVA so the needed splicing power from PLN using customer of 329 kVA with use transformer with 400 kVA capacity and required generator set capacity of 400 kVA. The load on the LVMDP panel is 254,725 watts with KHA 569 A, so using MCCB with a rating of 630 A, using cable 7 x NYY 1c x 185 mm 2 with drop voltage 7.47 Volts or by 1.96% on the network 3 phase system. By PUIL 2011 standard decline voltage maximum of 4% so that the drop in the voltage on the LVMDP panel is still by the required standard.

Consensus based distributed secondary control for current sharing and voltage restoration considering local loads and constant power loads in dc microgrids

ABSTRACT Ensuring accurate current sharing and regulating output voltage is challenging in DC microgrids. Conventional droop control has limitations in achieving voltage regulation and accurate current sharing. Unequal transmission line resistances, local loads, and constant power load (CPL) add to the complexity. To tackle this issue, this paper presents a novel consensus based distributed secondary control that determines the resistance of transmission lines by injecting an external pulse to the reference voltage of each converter, and then measuring the resulting changes in output voltage and current. The proposed secondary control signal, denoted as ψi , enables simultaneous proportional current sharing and voltage restoration in the DC microgrid. To guarantee the stability of the proposed method, a comprehensive stability analysis of the system is performed. In contrast to similar methods, the proposed method enables achieving precise proportional current sharing and voltage restoration, even when faced with varying resistive loads and CPLs. Furthermore, the proposed method exhibits remarkable features including, high convergence speed, the capability to determine transmission line resistances instead of assuming them to be known, and robustness in plug-and-play scenarios and communication system failures. The proposed method is validated through simulations in MATLAB and experimental tests, affirming its effectiveness.

A 55 μ W 2.4 GHz wake-up receiver with offset-based peak detection achieving −90dBm sensitivity for IoT applications

The paper proposes a 2.4 GHz ultra-low power wake-up receiver (WuRX) with offset-based peak detection and mixer-first based radio frequency (RF) front-end for IoT applications. The mixer-first based front-end eliminates RF modules to reduce power consumption. Based on the transparency of the passive mixing switches, a 2-path passive mixer (2-PPM) constructs the high-Q band-pass filter (BPF) at the RF port to improve out-of-band blocker rejection. The offset-based peak detection circuit adaptively extracts the reference voltage for the subsequent comparator according to the real-time signal amplitude of envelope detection, which eliminates the misjudgment of the comparator and improves the accuracy of demodulation. For low power consumption, a ring oscillator is used to generate the local oscillator (LO) signal and the frequency calibration scheme combined with coarse tuning and fine tuning is employed to improve the frequency stability, which completes 10-bit frequency tuning with 2 MHz resolution. Designed in TSMC 28 nm CMOS technology, the mixer-first based front-end achieves a conversion gain of 42 dB and a noise figure of 11.9 dB at 2.4 GHz, an S11 less than −15dB during 2.4–2.5 GHz. The frequency calibration scheme for the ring oscillator completes the 512 MHz dynamic range with a 2 MHz frequency tuning step. The WuRX can achieve −90dBm sensitivity with 55 μ W power consumption at 0.6 V supply voltage and the chip area of 0.19 mm × 0.24 mm.

A 353pW, 0.014%/V line sensitivity self-biased CMOS voltage reference with source degeneration active load

A 353pW, 0.014%/V line sensitivity self-biased CMOS voltage reference with source degeneration active load

Quantized conductance in hybrid split-gate arrays of superconducting quantum point contacts with semiconducting two-dimensional electron systems

A quantum point contact (QPC)—a constriction in a semiconducting two-dimensional electron system with a quantized conductance—is a building block of novel spintronic and topological electronic circuits. QPCs can also be used as readout electronics, charge sensors, or switches in quantum nanocircuits. A short and impurity-free constriction with superconducting contacts is a Cooper-pair QPC analogue known as a superconducting quantum point contact (SQPC). The technological development of such quantum devices has been prolonged due to the challenges of maintaining their geometrical requirement and near-unity superconductor-semiconductor interface transparency. Here, we develop advanced nanofabrication, material and device engineering techniques and report on an innovative realization of nanoscale hybrid SQPC arrays with split gate technology in semiconducting 2D electron systems. We exploit the special gate tunability of the quantum wells, and demonstrate the first experimental observation of conductance quantization in hybrid InGaAs-Nb SQPCs. We observe reproducible quantized conductance at zero magnetic fields in multiple quantum nanodevices fabricated in a single chip and systematically investigate the quantum transport of SQPCs at low and high magnetic fields for their potential applications in quantum metrology, for extremely accurate voltage standards, and fault-tolerant quantum technologies. Published by the American Physical Society 2024

Parallel Operation Strategy of Inverters Based on an Improved Adaptive Droop Control and Equivalent Input Disturbance Approach

The operation of parallel inverters in microgrids is an important way to expand system capacity, but there are problems of circulating current fluctuations and power sharing errors in parallel inverters’ operation. In this paper, a parallel operation strategy for inverters based on improved adaptive droop control and Equivalent Input Disturbance (EID) is proposed. Firstly, the model and control topology of parallel inverters are presented. Secondly, in order to solve the power sharing error caused by impedance difference and the voltage drop caused by virtual impedance, a reference voltage generator based on improved adaptive droop control is proposed. Then, considering the circulating current fluctuation as a disturbance, a voltage controller based on an equivalent input disturbance approach is proposed to reduce the disturbance. Finally, simulation in MATLAB/Simulink is carried out to verify the effectiveness of the parallel operation strategy.

A control method for the single-phase three-leg unified power quality conditioner without a phase-locked loop

The single-phase three-leg unified power quality conditioner (UPQC) can achieve the functions of voltage compensation, reactive power compensation, and harmonic compensation. However, traditional control algorithms require a phase-locked loop to obtain the real-time phase angle of the grid voltage, which undoubtedly increases algorithm complexity. To simplify the phase-locked calculation, this paper proposes a control method without the phase-locked loop for the single-phase three-leg UPQC. In the proposed scheme, the instantaneous value of the grid voltage is employed to realize the grid integration control. Then, the load voltage reference is calculated in real time using a second-order generalized integrator. Moreover, a simple algorithm for reactive power and harmonic compensation is discussed, further simplifying the control algorithm. Finally, a small-scale experimental platform is built, and the effectiveness of the proposed method is verified by the experimental results.

Photovoltaic-Based q-ZSI STATCOM with MDNESOGI Control Scheme for Mitigation of Harmonics

Static compensators (STATCOMs) are often used in distribution systems to enhance power quality. There is a need to enhance the performance of STATCOM to optimize its utilization and facilitate the provision of additional ancillary services. This paper employs the multilayer discrete noise-eliminating second order generalized integrator (MDNESOGI) to regulate the quasi-impedance source inverter (qZSI)-STATCOM for power exchange with the grid. Compared to conventional second-order generalized integrator (SOGI), MDNESOGI exhibits a higher capability for rejecting DC offset. In instances of abnormal grid operation or system malfunction, the inclusion of DC rejection capability enhances the robustness and reliability of the system. The suggested control algorithm only requires two integrators, three mathematical operators, and a damping factor, making it far easier to implement than transformation-based methods. The distorted load current is broken down into its active and reactive components using this control mechanism. The reference currents are then calculated by multiplying these parts by their corresponding voltage standards. The DC offset is reduced and transient oscillations in the weight component are eliminated by adjusting the damping factor. The suggested algorithm effectively handles power quality tasks like (a) reducing harmonic distortion, (b) compensating for reactive power, (c) adjusting for power factor, and (d) balancing the load under different conditions in the distribution system. The experimental study results are used to examine the stability of the proposed control scheme in both static and dynamic scenarios. In addition, a comparison to traditional methods is provided to demonstrate the new method’s superiority. Experimentation results show that the suggested controller is superior to its contemporaries in all scenarios where power quality is a factor, meeting the IEEE standard requirements.