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Trade-off between transient response and grid-side current quality is a well-known issue of single-phase mains-connected power converters. A dual-loop control structure (usually based on PI or type-II controllers) is typically employed in such systems to regulate the DC link voltage to a constant reference (in order to maintain power balance) while forcing the grid-side current to have a specific shape (in order to comply with power quality requirements). Introducing notch term/s (tuned to certain multiple/s of the mains base frequency) into one of the loops allows either for the improvement of the dynamic performance without worsening the total harmonic distortion of grid-side current or for the enhancement of the current quality without impairing the dynamic response. Since the maximum tolerable value of total harmonic distortion is typically imposed by a certain power quality standard, it is desirable to enhance the transient response of the power converter system as much as possible while keeping the total harmonic distortion at the maximum allowed value. However, universal off-grid operating power conversion systems must support both 50 Hz and 60 Hz mains; consequently, tuning the notch term/s to 50 Hz multiple/s would not be sufficient for a 60 Hz mains operation and vice-versa. Consequently, this work examines the possibility of introducing a dual-notch term into the control loop in order to cover both above-mentioned base frequencies. It is demonstrated that under typical base frequency uncertainty values, the performances of dual-notch terms are nearly decoupled so that the term tuned to a 50 Hz frequency (and optionally to its multiples) has nearly no influence at a 60 Hz mains operation and vice-versa. Consequently, the methodology allows for the improvement of the dynamics of universal grid-connected power converters without total harmonic distortion (THD) deterioration. A stability analysis of the proposed control structure is carried out and quantitative design guidelines, allowing for the attainment of an optimized dynamic response for a given maximum tolerable total harmonic distortion, minimum allowed phase margin and a certain base frequency uncertainty, are established. It is shown that a DC link voltage loop bandwidth of 52 Hz may be attained while keeping the grid-side current THD below 5%. Simulations and experimental results support well the proposed design methodology. [ABSTRACT FROM AUTHOR]

Time-of-flight mass spectrometry is a commonly mass spectrometry technique that is widely used in biomedicine, environmental science and food science. The multiple reflection time-of-flight (MR-TOF) mass analyzer is a new type of mass analyzer with ultra-high mass resolution and has been used at institutions, such as Helmholtz Centre for Heavy Ion Research (GSI), European Organization for Nuclear Research (CERN) and High Energy Accelerator Research Organization (KEK) to measure short-lived ion masses, separate isobar and store ions. As the demand for use increasing, it is becoming important to improve the resolving power of MR-TOF mass analyzers. However, the optimization of the voltage parameters of MR-TOF mass analyzers is a high-dimensional, highly refined and non-linear problem, which is difficult to solve optimally by analytical method. In this study, a particle swarm optimization (PSO) algorithm-based method for optimizing the voltage parameters of MR-TOF mass analyzers was proposed. The method used an improved particle swarm optimization (IPSO) approach with a inertia weight decay strategy. The optimization method was tested on the SIMION ion optics simulation platform. Considering 133Cs+ ion with E-1.5 keV, δE = 8.5 eV, δx = δy = 1 mm, δα = δβ 1.5 mrad, a mass resolving power over 8.1X105 was achieved when A=0 ns and a mass resolving power over 5.0X105 was achieved when Δt=20 ns. IPSO optimized the best results to achieve the 2nd order focus of time with respect to energy for the MR-TOF mass analyzer, and the deviation of the ion's half-turn time of flight was within 1. 3×10-6. In 20 times experiments. IPSO improved the maximum results by 33%, the average results by 35% and the standard deviation by 29% compared with PSO optimization, providing better solution quality and stability. IPSO's linear decay strategy effectively controlled the reduction of the voltage update step size and was able to meet the global search and refinement of the MR-TOF mass analyzer voltage parameter optimization problem. It had good convergence and convergence speed. This work provided a fast and effective method for optimizing the voltage parameters of the MR-TOF mass analyzer and helped to improve the performance of this analyzer. The results showed that the IPSO is able to obtain a limiting mass resolution of more than 810 000, which has better performance compared with the PSO. The method has the advantages of simple operation, fast optimization and better solution, which can provide a method reference for voltage optimization of MR-TOF mass analyzer and thus improve the development efficiency of MR-TOF mass analyzer. [ABSTRACT FROM AUTHOR]

This paper presents a new nonlinear control scheme for a pulse-width modulated dc-dc Zeta converter operating in buck and boost modes. The averaged model of the dc-dc power converter is derived, based on which a robust control law is developed using a simplified sliding-mode control technique. The existence and stability conditions are introduced to select proper controller gains that ensure fast output voltage convergence towards reference voltage. A detailed design procedure is provided to realize the control scheme using low-cost discrete components. The proposed control method handles large disturbances, accommodates the non-minimum phase property, and maintains regulated output voltage during step-up and step-down operation modes. The control system also maintains constant switching frequency, improves the transient response, and eliminates the steady-state error at the output voltage. A MATLAB/SIMULINK model is developed to simulate the closed-loop dc-dc Zeta converter in continuous conduction mode and investigate the tracking and regulation performance. The simulation results confirm the robustness and stability of the nonlinear controlled power converter under abrupt line and load variations. [ABSTRACT FROM AUTHOR]

This manuscript presents an optimal control system for energy management of the hybrid energy storage system (HESS) as battery and super capacitor (SC) on electric vehicles (EVs). The proposed system is parallel execution of levy flight with Tunicate swarm optimization. The proposed method is improved by levy flight distribution; hence, it is named Improved Tunicate swarm optimization (ITSA). Here, the HESS method calculates the super capacitor reference voltage in terms of load dynamics and improves the power. At first, compute the super capacitor reference voltage assuming real-time load dynamics. Furthermore, diminish the range of battery power magnitude and power loss concurrently. In the proposed system, the Improved Tunicate swarm optimization is merged for generating the probable HESS control signal data set. Furthermore, the proposed method gains the super capacitor voltage, amount of battery current, variation of battery current. Through the proposed method, the hybrid energy storage system parameters are enhanced, and the proposed system gives a reliable solution. The proposed method is performed on the MATLAB/Simulink work platform. The quality of a hybrid energy storage system is compared with that of other methods. [ABSTRACT FROM AUTHOR]

In this paper, a maiden application of combined voltage and frequency control ensures voltage, frequency, and power regulation in diverse standalone low voltage AC microgrid (MG) networks by combining flexible improved droop control (IDC) with a novel fractional-order controller (FOC) proposed. An effort is made to design an IDC into the control loop based on virtual power, virtual negative resistance, inductance, and FOC to ensure power decupling and compensate voltage source converter (VSC) based distributed generators feeder voltage drop. A maiden proportional fractional integral derivative filter plus double derivative (P I λ D F D 2) controller is used to precisely monitor VSC voltage and current reference value for reducing the control errors. The controller robustness regarding system parameters uncertainties, unmodeled dynamics, and disturbance in the MG system is ensured by a new memetic salp swarm algorithm by finding optimal P I λ D F D 2 controller parameters. Several simulation studies in the MATLAB Simulink environment were conducted to verify the efficacy of the proposed technique. The suggested control methodology is also investigated by hardware in the loop using the OPAL-RT real-time simulator platform to demonstrate the controllers practical functional realization. The findings confirmed the efficacy of the proposed strategy. [ABSTRACT FROM AUTHOR]

Taking the permanent magnet synchronous motor (PMSM) as the research object, the model prediction pulse pattern control (MP3C) of a PMSM running in the medium–low-speed zone is adopted to further reduce the torque ripple and phase current total harmonic distortion (THD) of a motor running in the medium–low-speed zone. First, the objective function of the predictive pulse control method is optimized. The objective function is intended to be the difference between the switching voltage vector and the equivalent reference voltage vector. At the same time, the integral of the difference between the d-axis current reference value and the actual value is compensated into the voltage reference vector. Thus, the pulse pattern control selected by the objective function is optimal when the motor is running in the medium–low-speed region. In addition, the PMSM can run stably and reliably. Simulation results show that the torque ripple is reduced by 1.3 Nm and 1.2 Nm, and that the phase current total harmonic distortion is reduced by 0.10% and 0.03% when the motor is running at 5 Nm and 10 Nm and at a speed of 100 rpm, respectively. When the rotation speed is 1000 rpm, the torque ripple is reduced by 0.74 Nm and 0.78 Nm respectively. In addition, the phase current total harmonic distortion is decreased by 0.44% and 0.54%, respectively. [ABSTRACT FROM AUTHOR]

In recent years, nacelle test benches for wind turbines have been developed internationally. New standards are currently being developed that explicitly refer to the measurement of the electrical properties of wind turbines on these test benches. Thus, they are suitable for measuring the electrical properties required for certification. Another part of the certification is the creation and validation of suitable models of the wind turbine, which are used for stability analyses of the utility grid. Validation requires a suitable model of grid replication on the test benches, which is not yet covered by any applicable standard. Such models should be as simplified a representation of the artificial grid replication as possible to ensure that they are accessible to certification bodies. A model of the grid emulator installed at the CWD of RWTH Aachen University, which was validated with real measurement data, serves as a reference. A step-by-step reduction of the model's depth up to the system's technical representation is followed by a model evaluation with respect to the level of detail and an analysis of time and frequency. The evaluation shows that even a highly simplified model consisting of a reference voltage and an impedance replica meets the requirements for the validation of wind turbine models according to IEC 61400-27-2. [ABSTRACT FROM AUTHOR]

Traditional model predictive control (MPC) for the induction motor fed by a three-level inverter needs to explore 27 voltage vectors to obtain the optimal one, which leads to high switching frequency and requires too much computation. To solve this issue, a low switching frequency model predictive control with partition optimization is proposed. First, the reference voltage vector can be gained from the prediction model at the next time, and the space voltage vector plane is divided into 12 sectors for further vector choice. Furthermore, considering inverter constraints, the candidate voltage vectors are determined according to the sector location of the reference voltage vector. In this way, the candidate vectors can be reduced to 3 at most. Then, a boundary circle limit is designed to avoid unnecessary switch changes. If the reference voltage vector is within the boundary limit, the switches do not act, which can reduce the system switching frequency without introducing the extra weight coefficient into the cost function. These selected voltage vectors are substituted into the cost function to determine the optimal one. Finally, the neutral point voltage deviation is controlled by the positive and negative redundant small vectors to realize the multi-objective constraint without weighting coefficients. The simulation results show that the proposed control method can significantly reduce the switching frequency; at the same time, both the dynamic and steady performances can be maintained well, and the cost function has no weight coefficients. [ABSTRACT FROM AUTHOR]

An Auto-Trimming CMOS Bandgap References Circuit (ATBGR) with PSRR enhancement circuit for Artificial Intelligence of Things (AIoT) chips is presented in this paper. The ATBGR is designed with a first-order temperature compensation technique providing a stable reference voltage of 1.25 V in the ranges of input voltages from 1.65 V to 4.5 V. An auto-trimming circuit is integrated into a PTAT resistor of BGR to minimize the influences of the process variations. The four parallel resistor pairs with PMOS switches are connected in series with the PTAT resistor. The reference voltage, VREF, is compared to an external constant value, 1.25 V, through an operational amplifier, and the output of the de-multiplexer is used to configure the PMOS switches. High power supply rejection is achieved through a PSRR enhancement circuit constituting a cascaded PMOS common gate pair. The ATBGR circuit is fabricated in 180 nm CMOS technology, consuming an area of 0.03277 mm2. The auto-trimming method yields an average temperature coefficient of 9.99 ppm/°C with temperature ranges from −40 °C to 125 °C, and a power supply rejection ratio of −90 dB at 100 MHz is obtained. The line regulation of the proposed circuit is 0.434%/V with power consumption of 54.12 µW at room temperature. [ABSTRACT FROM AUTHOR]

This study proposes a maximum power point tracking (MPPT) approach with two components: an Incremental Conductance (INC) MPPT for reference voltage regulation and a Model Reference Adaptive Controller (MRAC) for adjusting the duty cycle of the DC‐DC converter switch. A robustness test is performed on the system considering real‐world situations that involve an abrupt change in atmospheric conditions with load uncertainties. The probabilistic load distribution analysis is accomplished through levels of uncertainty (i.e., Probabilistic DOWN and UP) to guarantee the operation of the proposed INC‐MRAC controller while generating unexpected disturbances in the system. Using MATLAB/Simulink, the performances of the novel INC‐MRAC MPPT are comparatively analyzed with PO, INC, VSSPO, and ANN under realistic case studies in seven states. After comparative analysis, it is evident that the proposed MPPT offers less tracking time, i.e., 3.8 ms, to track maximum power point (MPP) with negligible steady‐state oscillation and ripples. It is about 3, 7, 9, and 10 times faster than ANN, VSSPO, INC and PO, respectively. Moreover, the tracking efficiency of the proposed controller is up to 99.63% as well as overall efficiency of the system is more than 98%. The tracking power loss and error rate in finding MPP for the proposed controller is the lowest among all state‐of‐the‐art MPPT approaches. Finally, the effectiveness of the proposed INC‐MRAC approach is experimentally validated by employing a real‐time simulator OPAL‐RT (OP4510). The study helps in environmental protection and participation in sustainable development. [ABSTRACT FROM AUTHOR]

Line‐to‐line short circuits are the transient disturbances that cause the highest currents as well as the largest voltage imbalances in inverter‐based microgrids. This paper presents a control scheme for grid‐forming inverters in islanded microgrids that limits the current to a safe value during these types of short circuits while providing a lower voltage imbalance compared to state‐of‐the‐art current limiting techniques. This control scheme is based on reducing both the amplitude of the reference voltage with the maximum amplitude of the reference current and the instantaneous reference voltage with only the inductive component of the virtual impedance. The combination of these two control actions provides low voltage imbalance, as the theoretical and experimental studies reveal. This voltage imbalance improvement is the main contribution of this paper and is maintained when the microgrid supplies linear and non‐linear loads. In the theoretical study, the paper includes control design guidelines to satisfy static and dynamic specifications. The theoretical predictions are validated by means of experimental results measured in a laboratory microgrid. A practical performance comparison of current limiting techniques based on experimental tests is also reported. [ABSTRACT FROM AUTHOR]

Direct torque control (DTC) is one of the most prominent control techniques used by permanent magnet synchronous motor (PMSM) drives in industry applications. Nevertheless, the presence of hysteresis controllers and inaccurate voltage switching table in traditional DTC results in higher torque and flux ripple. This study proposes an enhanced DTC functioned Surface‐mounted PMSM (S‐PMSM) drive with mitigation of torque and flux ripple. The operation relies on generating the reference voltage vector (VV) in a stationary reference frame, which supports control of torque and flux without hysteresis controllers. The reference VV generation is simple and does not affect control robustness. The position of reference VV in a sector is used to build the voltage vector (VV) switching table. As a result, the application of nearest discrete VV to reference VV produces optimal torque and flux control. Moreover, redundant switching combinations of null VV are effectively used for possible minimization of switching frequency of two‐level voltage source inverter (VSI) supplied S‐PMSM drive. Therefore, proposed DTC gains improved S‐PMSM drive response along with switching frequency reduction. In dSPACE‐RTI 1104 platform, experimental response of S‐PMSM drive under various operating conditions have been depicted to highlight the proficiency of proposed DTC in comparison with existing DTC. [ABSTRACT FROM AUTHOR]

This paper deals with the optimal design of different VLSI circuits, namely, the CMOS voltage reference circuit and the CMOS ring oscillator (RO). The optimization technique used here is the multiobjective differential evolution algorithm (MDEA). All the circuits are designed for 90 nm technology. The main objective of the CMOS voltage reference circuit is to minimize the voltage variation at the output. The targeted value of the reference voltage is 550 mV. A CMOS ring oscillator (RO) is designed depending on the performance parameters such as power consumption and phase noise. The optimal transistor sizing of each circuit is obtained from MDEA. Each circuit is implemented in SPICE by taking the optimal dimensions of the transistors, and the performance parameters are achieved. The designed voltage reference circuit achieves a reference voltage of 550 mV with 600 nW power dissipation. The reference voltage variation of 8.18% is observed due to temperature variation from −40°C to + 125°C. The MDEA-based optimal design of RO oscillates at 2.001 GHz frequency, has a phase noise of −87 dBc/Hz at 1 MHz offset frequency, and consumes 71 μW power. This work mainly aims to optimize the MOS transistors' sizes using MDEA for better circuit performance parameters. SPICE simulation has been carried out by using the optimal values of MOS transistor sizes to exhibit the performance parameters of the circuit. Simulation results establish that design specifications are closely met. SPICE results show that MDEA is a better technique for the optimal design of the above-mentioned VLSI circuits. [ABSTRACT FROM AUTHOR]

For grid‐connected solar photovoltaic (PV) applications, a hybrid cascaded MLI (H‐CMLI) topology based on cascaded H‐bridge MLI is proposed in this study. The proposed configuration is a hybrid of two common MLIs: Cascaded H‐bridge and three‐phase cascaded voltage source inverter (VSI). For the same voltage level, the proposed topology enhances the number of the generated voltage levels while employing fewer components, relative to other traditional MLI topologies. Furthermore, the voltage stresses on switches in the proposed topology are decreased, compared to when each part operates independently. The proposed topology could be utilized for many applications, such as PV‐grid connection, active power filters, and STATCOM. To verify the effectiveness of the proposed topology, the model is developed in MATLAB/Simulink environment, in which a closed‐loop control scheme based on the traditional one is used to achieve the PV‐grid connection. Alongside the simulation results, the proposed topology and its control scheme are experimentally implemented in the laboratory. Two cases were experimentally applied to validate the successful performance of the proposed H‐CMLI: Open‐loop control and closed‐loop control for PV‐grid integration. The proposed control scheme effectively maintains the DC link voltage at its reference voltages. Also, the closed‐loop control scheme is capable of providing the power factor at unity and maintaining the total harmonic distortion (THD) of grid current within the acceptable limit. To demonstrate the proposed topology's functionality and viability, experimental results are provided. [ABSTRACT FROM AUTHOR]

With the widespread application of permanent magnet synchronous motor (PMSM) drives, the demand for safety and reliability has increased. Inverter open-circuit fault is a frequent and severe failure that requires reliable detection and remedial measures. This paper proposes an open-circuit fault diagnosis technique based on voltage residual analysis that does not require additional voltage sensors. The proposed technique analyzes the characteristics of the reference voltage and the actual output voltage under both healthy and fault conditions. To achieve fast and reliable fault detection, it uses the DC component and second harmonic component in the residual voltage between estimated voltage and controller reference voltage. Once an open-circuit fault is detected, the polarity of the DC component is capable of identifying the fault location. The effectiveness and robustness of the proposed technique are verified through simulations and testing on a triple redundant PMSM under various load and speed conditions. [ABSTRACT FROM AUTHOR]

An innovative distributed secondary control technique for balanced current sharing and voltage regulation for an off-grid DC microgrid setup is presented in this research. The droop control scheme is conventionally used for current sharing amongst distributed sources (DSs) in a microgrid. However, this method has two major drawbacks. Firstly, due to the line resistance of each DS, the output voltage is different for each DS, and the output current-sharing property deteriorates. Secondly, the droop action increases the DC bus voltage variation. To address these drawbacks, a fuzzy-based distributed secondary controller is proposed. The proposed controller in each DS simultaneously ensures balanced current sharing and sustains DC bus voltage at the reference value by using a communication network to interact with one another. The required circumstance to guarantee the proposed controller's stability is provided. The stability analysis is beneficial to inform the choice of control parameters. The real-time simulation outputs demonstrate the proposed control scheme's robustness in achieving the control objectives under varying operating conditions. [ABSTRACT FROM AUTHOR]

The reference input dc voltage of grid connected voltage source inverter (GCVSI) is altered in this article based on power (both active and reactive) injection from GCVSI for minimising inverter switching losses, and total harmonic distortion (THD) of grid current. If the GCVSI is exclusively used for actual power injection from the photo-voltaic (PV) system to the utility grid, the needed input dc voltage of GCVSI is twice the utility grid phase peak voltage. According to the literature, GCVSI is also used to compensate for power quality issues, and in these circumstances, the dc-link voltage value is determined by the maximum power injection of GCVSI. Under reduced load, and reduced power generation from the PV system, keeping maximum GCVSI input dc voltage reference causes extra voltage stress at GCVSI switches, and the grid current THD is worse due to high ripple current in filter inductance. Therefore, to reduce the inverter switching losses and to improve the grid current THD, the relationship between the GCVSI input dc voltage reference and the power flow from GCVSI has been formulated. The proposed work is verified using simulation studies, as well as hardware studies, and the results are compared with existing methods for validation. [ABSTRACT FROM AUTHOR]

This paper demonstrates a low power, frequency compensated with on-chip capacitor, low dropout linear voltage regulator. The proposed low dropout regulator (LDO) delivers a constant output voltage of 2.4V for an input range of 2.5–6.8V. A minimal drop of 2mV and 20mV was observed at no load and full load output current of 0 A to 100mA, respectively. LDO is realized by a high-gain two-stage error amplifier, internally compensated by passive a high-pass filter to achieve stability over a load current range of 0–100mA without occupying as much area as an active high-pass filter. The LDO presented requires a bias current of 10 mA with a reference voltage of 1.5V and is designed in 180-nm technology. [ABSTRACT FROM AUTHOR]

The paper presents a simple control and high-accuracy measurement method for a four-electrode conductivity probe based on the principle of the bi-directional voltage pulse. The two-way differential AC (alternating current) pulse voltage signal for the reference resistance and solution resistance is modulated into the single DC stationary voltage response signal to drop the demand for software and hardware and effectively eliminate the influence of excitation voltage pulse amplitude on measurement accuracy, and then the synchronous rectification DC measurement is proposed without any control timing. Meanwhile, the mathematical expression between the single output DC voltage signal and the solution conductivity is given. The test results in the laboratory and in the field indicate that the relative error of the conductivity measurement is within 2.5% in a conductance range of 10 uS/cm to 200 mS/cm, and the proposed measurement method has a good application prospect in application. [ABSTRACT FROM AUTHOR]

A high energy-efficient and reference voltage self-adaptive switching scheme for a triple-capacitive array successive approximation register analog-to-digital converters is proposed. The proposed switching time scheme includes Bi-level and Tri-level modes. The operating mode can be automatically switched by the reference voltage self-adaptive module according to the number of reference voltages of the peripheral circuits. The proposed timing scheme has the advantage of automatic compatibility with Bi/Tri-level reference voltage, which can be better adapted to the requirements of different hybrid ADC architectures. In Bi/Tri-level mode, two-step method, and monotonic switching scheme, floating capacitor technology is used to achieving 99.6% and 99.9% savings in average switching energy and a 73.4% reduction in total capacitance compared to the conventional scheme when applied to a 10-bit SAR ADC. The INL and DNL for both the Bi-level reference mode and the Tri-level reference mode are 0.350, 0.347 and 0.177, 0.172, respectively. In addition, the scheme eliminates to reset energy while regulating M to achieve a compromise between energy, area, and linearity. The post-simulation results show that the 10-bit SAR ADC with the proposed switching scheme can achieve a signal-to-noise distortion ratio (SNDR) of 60.53 dB and a spurious-free dynamic range (SFDR) of 68 dB at a sampling rate of 20 MS/s in a 65 nm CMOS process. The area of this ADC is only 0.2392 mm2. [ABSTRACT FROM AUTHOR]

The grid‐forming converter (GFC) is used to regulate the voltage and frequency of a local grid. However, due to the limited current capacity, the GFC must actively modify its control strategy when a serious external fault occurs, thus to avoid the possible damage caused by overcurrent. This paper proposes a novel voltage reference generation method for GFC based on the external equivalent impedance magnitude (EEIM), which has the following merits: (i) the faulty phase currents and the non‐faulty phase voltage can be controlled within their operational limits. (ii) The voltage reference unbalance factor (VRUF) of the GFC can be adjusted flexibly if necessary. Then, in order to achieve the optimal support effect for the faulty phase voltages, a two‐stage GFC fault control strategy is proposed in this paper. In the first stage, the fault type is judged by computing and comparing the EEIM of each phase. In the second stage, the voltage reference mode is determined according to the fault type, and the VRUF is adjusted to its optimum value through a search algorithm. Simulation results based on Matlab/Simulink verify the effectiveness of the proposed GFC fault control strategy in terms of current limiting and faulty phase voltage support. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Model predictive direct power control (MPDPC) strategy offers numerous benefits over the traditional control strategies in active power filters (APF). However, the real-time execution duration (RTED) reduction of model predictive control in multilevel inverters is a big challenge. In this paper, an improved low-computation model predictive direct power control strategy for three-level four-leg APF (TL-FL-APF) is presented. First, based on generalized instantaneous reactive power theory, a new predictive power model for TL-FL-APF is established. Then, in order to reduce the RTED, classical multiple power predictions are converted into single voltage prediction through the principle of deadbeat control, and the optimized vector range is reduced from 81 to 4–18 by the method of spatial stratification using the γ-component of reference voltage vector. Finally, the simulation and experimental results demonstrate that the proposed low-computation MPDPC has excellent performance. [ABSTRACT FROM AUTHOR]

This article describes a closed-loop detection MEMS accelerometer for acceleration measurement. This paper analyzes the working principle of MEMS accelerometers in detail and explains the relationship between the accelerometer zero bias, scale factor and voltage reference. Therefore, a combined compensation method is designed via reference voltage source compensation and terminal temperature compensation of the accelerometer, which comprehensively improves the performance over a wide temperature range of the accelerometer. The experiment results show that the initial range is reduced from 3679 ppm to 221 ppm with reference voltage source compensation, zero-bias stability of the accelerometer over temperature is increased by 14.3% on average and the scale factor stability over temperature is increased by 88.2% on average. After combined compensation, one accelerometer zero-bias stability over temperature was reduced to 40 μg and the scale factor stability over temperature was reduced to 16 ppm, the average value of the zero-bias stability over temperature was reduced from 1764 μg to 36 μg, the average value of the scale factor stability over temperature was reduced from 2270 ppm to 25 ppm, the average stability of the zero bias was increased by 97.96% and the average stability of the scale factor was increased by 98.90%. [ABSTRACT FROM AUTHOR]

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To improve the power utilization efficiency of distributed energy units (DEUs) in DC microgrids, a centralized current iteration regulation approach is presented in this paper. The power utilization efficiency is partially represented by the power losses of DEUs, which can be modelled as quadratic functions of the output currents of DEUs. The power efficiency is also dependent on the line losses on the resistances between the DEUs and DC buses, which can be formulated in the basis of the output currents as well. Thus, the total power losses of DEUs comprise line and converter losses, which are verified to be a constrained‐convex function of the current allocation coefficients. In this paper, a primal‐dual subgradient method (PDSM) using only explicit addition and subtraction iterations is adopted to obtain the optimal current distribution coefficients. On this basis, an adaptive droop regulation scheme is applied to further control the output voltage references of DEUs, and proportional‐integral (PI) controllers are applied to track the adaptive voltages based on the current sharing errors. Both simulation and empirical results demonstrate the effectiveness of the proposed control to improve the power utilization efficiency of DEUs regardless parameter and load variations in DC microgrids. [ABSTRACT FROM AUTHOR]

This work introduces modified backstepping methods to design controllers for neutral point clamped (NPC) converters interfacing a DC/AC microgrid. The modified backstepping controllers are derived from a proper converter model, represented in dq coordinates, and are designed to regulate the DC voltage and to balance the two NPC converter DC capacitor voltages through a DC offset in the sinusoidal pulse width modulation (SPWM) carriers. The averaged and separated dynamics backstepping controllers also enforce nearly sinusoidal AC currents at a given power factor. The two proposed NPC converter controllers are evaluated through MATLAB/Simulink simulations and experimental implementation using a laboratory prototype. Simulations and experimental results show that the two modified backstepping controllers regulate the microgrid DC voltage in steady state and in transient operation, even with load disturbances or DC voltage reference changes, while enforcing nearly AC sinusoidal currents at a given power factor or injected reactive power. The modified backstepping-controlled NPC converter is bidirectional, converting energy from DC renewable energy sources or storage systems to AC or charging storage systems from AC. The results also highlight the effective balancing of the NPC DC capacitor voltages. [ABSTRACT FROM AUTHOR]

The aim of this research is to manage the voltage of an active distribution grid with a low X/R ratio and multiple Photovoltaic Distributed Generators (PVDGs) operating under varying conditions. This is achieved by providing a methodology for coordinating three voltage-based controllers implementing an Adaptive Neuro-Fuzzy Inference System (ANFIS). The first controller is for the On-Line Tap Changer (OLTC), which computes its adequate voltage reference. Whereas the second determines the required Active Power Curtailment (APC) setpoint for PVDG units with the aim of regulating the voltage magnitude and preventing continuous tap operation (the hunting problem) of OLTC. Finally, the last component is an auxiliary controller designed for reactive power adjustment. Its function is to manage voltage at the Common Coupling Point (CCP) within the network. This regulation not only aids in preventing undue stress on the OLTC but also contributes to a modest reduction in active power generated by PVDGs. The algorithm coordinating between these three controllers is simulated in MATLAB/SIMULINK and tested on a modified IEEE 33-bus power distribution grid (PDG). The results revealed the efficacy of the adopted algorithm in regulating voltage magnitudes in all buses compared to the traditional control method. [ABSTRACT FROM AUTHOR]

This paper presents a novel motion control strategy based on model predictive control (MPC) for distributed drive electric vehicles (DDEVs), aiming to simultaneously control the longitudinal and lateral motion while considering efficiency and the driving feeling. Initially, we analyze the vehicle's dynamic model, considering the vehicle body and in-wheel motors, to establish the foundation for model predictive control. Subsequently, we propose a model predictive direct motion control (MPDMC) approach that utilizes a single CPU to directly follow the driver's commands by generating voltage references with a minimum cost function. The cost function of MPDMC is constructed, incorporating factors such as the longitudinal velocity, yaw rate, lateral displacement, and efficiency. We extensively analyze the weighting parameters of the cost function and introduce an optimization algorithm based on particle swarm optimization (PSO). This algorithm takes into account the aforementioned factors as well as the driving feeling, which is evaluated using a trained long short-term memory (LSTM) neural network. The LSTM network labels the response under different weighting parameters in various working conditions, i.e., "Nor", "Eco", and "Spt". Finally, we evaluate the performance of the optimized MPDMC through simulations conducted using MATLAB and CarSim software. Four typical scenarios are considered, and the results demonstrate that the optimized MPDMC outperforms the baseline methods, achieving the best performance. [ABSTRACT FROM AUTHOR]

Instrument transformers are largely used to measure voltages and currents in public electricity networks. Their performance is essential for Power Quality measurements. Tests and procedures to estimate the effect of single influence factors are performed according to current standards. However, the instrument transformers are exposed simultaneously to more than one factor. The standardized procedures for their characterization with combined influence factors are under construction in Europe. The work in this paper is focused on the development of a new set-up for the determination of the accuracy and frequency response of medium-voltage transformers within the combined influence factors of temperatures and vibrations. The test set-up includes a platform for the combination of temperature and vibrations, a generating system for harmonics up to 9 kHz superposed with 35 kV, 50 Hz voltage and a reference measuring system. The results of several tests carried out on a 35 kV/100 V/50 Hz voltage transformer in the presence of these influence factors are discussed in this paper. They show that the accuracy and frequency response of the voltage transformers are more influenced by temperature than by vibrations. [ABSTRACT FROM AUTHOR]

This paper analyzes the cause of electric vehicle battery fires. The fundamental cause is attributed to a low cell balance current, and it is proven that the variation in the battery's internal voltage due to temperature change is the decisive reason for battery fires. In this paper, the authors studied a method of solving the problem by changing only the software of the existing Battery Management System (BMS) without changing the hardware. Batteries cannot be made with 100% capacity, resulting in voltage division. Cell balancing is performed to prevent such phenomena, but a low cell balance current prevents the proper operation of cell balancing. As a result, relatively small batteries, due to progressive degradation, have continuous voltage rise toward overvoltage. Subsequently, an additional voltage rise occurs as the chemical activity of the battery increases due to temperature rise. In this paper, a new cell balancing method is proposed to limit the aging process of cells with a relatively small capacity and peak voltage. In addition, it was validated through simulation using MATLAB R2019a. [ABSTRACT FROM AUTHOR]

Copyright of Electric Power Automation Equipment / Dianli Zidonghua Shebei is the property of Electric Power Automation Equipment Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electric Power Automation Equipment / Dianli Zidonghua Shebei is the property of Electric Power Automation Equipment Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To meet the demand of low bit error rate and high bandwidth for high-speed links, a reliable 112 Gb/s four-level pulse amplitude modulation (PAM4) transceiver design scheme with adaptive threshold voltage and adaptive decision feedback equalizer is proposed in this paper. In this scheme, three continuous time linear equalizers (CTLEs) at the front end of receiver are used to compensate the high-frequency, mid-frequency and low-frequency signals, respectively, and the variable gain amplifier (VGA) and saturation amplifier (SatAmp) are used to scale the signal amplitude. In addition to the three data samplers, four auxiliary samplers are also used for threshold adaptation. The sign-sign least mean squares algorithm uses the offset between the data sampler and the auxiliary sampler at the receiver side to drive the auxiliary reference voltage to converge to the signal constellation level, thus ensuring that the eye diagram of the PAM4 received signal has equal spacing and a constant signal–noise ratio for the three eyes in the vertical direction. In addition, the adaptive DFE for PAM4 signaling allows the transceiver to better adapt to the channel and thus achieve better equalizer performance. The simulation results show that the PAM4 transceiver design can compensate up to 25 dB of channel loss with an average eye height of 59.6 mv and an average eye width of 0.27 UI at a bit error rate of 10−12 under the condition of 3-tap feedforward equalizer (FFE) transmitter. [ABSTRACT FROM AUTHOR]

Conventional deadbeat predictive current control (DBPCC) based on space vector modulation (SVM) shows quick dynamic responses and a good steady‐state performance in induction motor (IM) drives. However, the motor parameters change during operation due to temperature and saturation changes, leading to inaccurate reference voltage vectors and a degraded performance. Furthermore, conventional DBPCC uses a fixed vector sequence of 0127 over the entire speed range, which results in large current harmonics at high modulation indices. To address the above issues, this paper proposes a robust deadbeat predictive current control (RDBPCC) for IM drives. Based on an ultra‐local model, the proposed method updates the input voltage gain and unknown system components online according to the voltage and current of the previous two control cycles. Because the final control expression contains only the measured stator current and voltage values, the model shows a strong robustness. The steady‐state performance is significantly improved by selecting the optimal vector sequence according to the modulation index based on the principle of current harmonic minimization. The experimental results confirm that, compared with conventional vector control and conventional DBPCC, the proposed method achieves a strong parameter robustness and reduces the current total harmonic distortion (THD) by more than 10% and 20% at high‐modulation indices. [ABSTRACT FROM AUTHOR]

The shift towards sustainable energy sources is gaining momentum due to their environmental cleanliness, abundant availability, and eco-friendly characteristics. Solar energy, specifically harnessed through photovoltaic (PV) systems, emerges as a clean, abundant, and environmentally friendly alternative. However, the efficacy of PV systems is subjective depending on two critical factors: irradiance and temperature. To optimize power output, maximum power point tracking (MPPT) strategies are essential, allowing operation at the system's optimal point. In the presence of partial shading, the power–voltage curve exhibits multiple peaks, yet only one global maximum power point (GMPP) can be identified. Existing algorithms for GMPP tracking often encounter challenges, including overshooting during transient periods and chattering during steady states. This study proposes the utilization of fuzzy sliding mode controllers (FSMC) and fuzzy proportional-integral (FPI) control to enhance global MPPT reference tracking under partial shading conditions. Additionally, the system's performance is evaluated considering potential sensor malfunctions. The proposed techniques ensure precise tracking of the reference voltage and maximum power in partial shading scenarios, facilitating rapid convergence, improved system stability during transitions, and reduced chattering during steady states. The usefulness of the proposed scheme is confirmed through the use of performance indices. FSMC has the lowest integral absolute error (IAE) of 946.94, followed closely by FPI (947.21), in comparison to the sliding mode controller (SMC) (1241.6) and perturb and observe (P&O) (2433.1). Similarly, in integral time absolute error (ITAE), FSMC (56.84) and FPI (57.06) excel over SMC (91.03) and P&O (635.50). [ABSTRACT FROM AUTHOR]

The full-bridge submodule (FBSM)-based modular multilevel converter (FBSM-MMC) offers promising performance due to its ability to output negative FBSM voltage. This paper studies this ability of the FBSM-MMC under zero-sequence voltage injection (ZSVI) and second-order harmonic current injection (SHCI). The focus of the research is to redistribute the FBSM powers by injecting an additional power degree of freedom, resulting in a smaller FBSM capacitor voltage ripple, while keeping the maximum AC output voltage for a given fundamental frequency component of the arm voltage reference. Accordingly, a control strategy was developed, based on non-sinusoidal ZSVI, and SHCI is proposed for further improving the performance of the FBSM-MMC. The proposed non-sinusoidal ZSVI contains a higher sinusoidal third-order harmonic component than that of pure sinusoidal third-order voltage injection (THVI) when operating under the same maximum AC output voltage. By implementing this solution, a smaller amplitude of the injected second-order harmonic current can be achieved, producing a lower power loss in the FBSM-MMC. Considering the proposed solution, the relationship of the arm powers and FBSM capacitor voltages are also discussed. Finally, the simulation results and experimental results are presented to verify the effectiveness of the theoretical analysis of the proposed method. [ABSTRACT FROM AUTHOR]

Summary: In this paper, a new ultra‐low‐power voltage reference based on a two‐stage, all‐pMOS topology operating in the subthreshold region is proposed to uniquely meet the pW‐power range power consumption requirements of emerging Internet‐of‐Things applications without significantly compromising the temperature coefficient (TC) and the line sensitivity (LS) performance. The proposed circuit consists of the LS regulator, TC corrector, and TC trimming sections. Based on post‐layout Monte Carlo simulations in 180‐nm CMOS, the proposed circuit operates with 0.8‐ to 2.4‐V supply potential and generates a reference voltage of 206 mV with a process spread of 7.8%, achieving an average calibrated TC of 4.4 ppm/°C in the temperature range of −20°C to 80°C, and an average LS of 51.5 ppm/V with a power consumption of 25.9 pW at 25°C (469.1 pW at 80°C). [ABSTRACT FROM AUTHOR]

This paper proposes a stochastic optimal power allocation strategy for a droop controlled islanded microgrid (DCIMG) with a medium X/R ratio in presence of combined heat and power-based distributed generators (DGs), renewable generators, switched capacitor banks, plug-in hybrid electric vehicle (PHEV) loads, voltage dependent electric loads and heat loads. Optimal values of stochastic power demand due to PHEV charging and discharging load are determined based on the goals of achieving target state-of-charge of PHEV batteries and effective peak shaving during peak load periods, respectively. Active power of dispatchable DGs is optimally allocated depending on the simultaneous fulfillment of an economic objective, an environmental objective along with three network related objectives. Hong's 2m+1 point estimate method (PEM) and Hong's 2m+1 PEM coupled with Nataf transformation (NT) are employed to handle the uncorrelated uncertainties accompanied with PHEV load demand and the correlated uncertainties associated with spatially correlated renewable generation and load demand. Active and reactive power static droop coefficients, and frequency and voltage reference settings of the dispatchable DG units are considered as the control variables for optimal dispatching of active power. A modified hybrid particle swarm and grey wolf optimizer embedded in fuzzy framework is used to solve the constrained multi-objective optimization problem. The efficacy of the proposed framework is validated on a 33-node droop controlled islanded microgrid test system. • A modified hybrid PSO-GWO algorithm is proposed for optimal power allocation among dispatchable DGs. • Fuzzy based approach is adopted for solving multi-objective optimization problem. • PHEV charging/discharging load and voltage dependent load models are used. • Hong's 2 m + 1 PEM with Nataf Transformation is employed to model the correlated uncertainties. [ABSTRACT FROM AUTHOR]

In this paper, an improved fixed-frequency-based integral sliding mode controller is designed and applied to a stand-alone photovoltaic (PV) system to obtain the desired reference signal for the maximum power point tracking. The proposed technique is designed with the modified sliding surface and sigmoidal function-based control law which improves the transient and steady-state performance of the PV system under uniform and partial shading conditions. Moreover, the cost of the proposed technique is further reduced by predicting the inductor current without employing a current sensor. In addition, the varying tuning factor strategy is used to further reduce the undershoot and overshoot issues during the tracking process. The desired voltage reference signal is provided by the online fractional open-circuit voltage algorithm. Furthermore, the proposed sliding mode control technique is integrated with the 0.8 Voc model-based algorithm to obtain the global maximum power point. To check the effectiveness and fair analysis, the proposed technique is tested in MATLAB/Simulink environment under partial shading conditions, and its results are compared with the recently developed double integral derivative sliding mode control technique. The suggested technique is also tested experimentally on a 245 W PV module, in conjunction with a boost converter. The simulation and experimental findings reveal that the proposed technique outperforms the double integral derivative sliding mode control technique in terms of steady-state and transient performance, tracking speed, and transient efficiency. [ABSTRACT FROM AUTHOR]

This paper presents a low-power sub-bandgap voltage reference. Here, the proportional to absolute temperature (PTAT) voltage obtained from ∆VEB is applied to a subthreshold diode-connected PMOS transistor to yield a current with a positive thermal coefficient (TC). The current is then converted back to a PTAT voltage term using another subthreshold PMOS transistor at the output path. Moreover, utilizing the bipolar transistor achieves a lower process variation VR. A trimming circuit is also applied to improve the TC against the process variation further. Low-power VR is achieved by operating all the MOSFETs under the subthreshold region. The simulation results using the standard 1.8 V, 0.18 µm CMOS process shows a nominal output voltage of 0.75 V, operating from 0.9 V to 1.8 V supply voltage while consuming 41.4 nA at room temperature. The TC is about 21.6 ppm/oC and (σVREF/μVREF) = 1.0 % over a temperature range of 0 °C to 120 °C. In addition, the proposed VR circuit is simulated without a trimming circuit resulting in a reasonable μTC = 29.1 ppm/oC and (σVREF/μVREF) = 1.3%. [ABSTRACT FROM AUTHOR]

This paper proposes a model predictive current control (MPCC) method for a three-leg two-phase voltage source inverter to reduce the ripple of the output current. The proposed MPCC method is based on discrete space vector modulation, which is implemented by eliminating nonlinear modulation regions and generating virtual voltage vectors based on the stationary reference voltage vector axis. In addition, based on a voltage angle estimated using load parameters, the candidate voltage vectors in a specific region are generated, which reduces the calculation burden. Subsequently, the cost function is calculated using these candidate voltage vectors, and the optimal voltage vector selected using the proposed MPCC method is more accurate than the vector selected using the conventional MPCC method. Therefore, by applying the proposed method to increase the number of virtual voltage vectors, it is possible to obtain a delicate reference voltage. Consequently, the total harmonic distortion of the output current is reduced, resulting in an increase in power quality. The effectiveness and feasibility of the proposed method are verified through simulations and experiments. [ABSTRACT FROM AUTHOR]

This paper proposed a compensation method for the output voltage errors of a PWM inverter. Output voltage errors occur under low sampling-to-fundamental frequency ratio operating conditions, and they can be compensated by calculating a switching timing in which the average of the output voltage during one sampling period is equal to the voltage reference. The proposed compensation method for output voltage errors was described according to the PWM method and the voltage update method, and it was verified by simulation and experimental results. It was confirmed that a lower sampling-to-fundamental frequency ratio results in a larger output voltage error. In addition, it was also confirmed that the proposed compensation method can completely remove these errors. [ABSTRACT FROM AUTHOR]

Nowadays, cars are an essential part of daily life, and failures, especially of the engine, need to be avoided. Here, we used the determination of the battery voltage as a reference measurement to determine possible malfunctions. Thereby, we compared the use of a digital oscilloscope with the direct measurement of the battery voltage via the electronic control unit. The two devices were evaluated based on criteria such as price, sampling rate, parallel measurements, simplicity, and technical understanding required. Results showed that the oscilloscope (Picoscope 3204D MSO) is more suitable for complex measurements due to its higher sampling rate, accuracy, and versatility. The on-board diagnostics (VCDS HEX-V2) is more accessible to non-professionals, but it is limited in its capabilities. We found that the use of an oscilloscope, specifically the Picoscope, is preferable to measure battery voltage during the engine start-up process, as it provides more accurate and reliable results. However, further investigation is required to analyse numerous influences on the cranking process and the final decision for the appropriate measurement device is case specific. [ABSTRACT FROM AUTHOR]

This paper proposes a modified distribution static compensator (DSTATCOM) with the voltage controller. The modified DSTATCOM is incorporated in a three-phase four-wire distribution network. The design criteria of the modified DSTATCOM parameters is introduced. The Hysteresis Voltage Controller (HVC) is used to drive the Voltage Source Converter (VSC) and its reference voltage signal is generated based on the Instantaneous Symmetrical Components Theory (ISCT) to provide the proper compensation to stabilise the system voltage, improve the power factor and mitigate the harmonic distortion. Matlab/Simulink software is used to verify the performance of the modified DSTATCOM with the used controller under different load types and supply voltage conditions. The control algorithm ensures that the bus voltage is maintained at its rated value during different connected loads and supply conditions. Also, it compensates the non-linear and unbalanced supply currents and reducing the Total Harmonic Distortion (THD) of both current and voltage. The proposed modified DSTATCOM gives better results in comparison with the conventional DSTATCOM. [ABSTRACT FROM AUTHOR]

The growing use of DC/DC power converters has resulted in the requirement that their complex controllers be cheaper and smaller, thus using cost-effective implementations. For this purpose, it is necessary to decrease the computational burden in controller implementation to minimize the hardware requirements. This manuscript presents two methods for tuning an adaptive linear–quadratic–Gaussian voltage controller for a battery charger/discharger, implemented with a Sepic/Zeta converter, to work at any operating point. The first method is based on a lookup table to select, using the nearest method, both the state feedback vector and the observer gain vector, solving the Riccati's differential equation offline for each practical operating point. The second method defines a polynomial function for each controller element that is based on the previous data corresponding to the system operating points. The adaptability of the two controllers to fixed voltage regulation and reference tracking was validated using simulations and experimental tests. The overshoot and settling time results were lower than 11% and 3.7 ms, which are in the same orders of magnitude of a control approach in which the equations are solved online. Likewise, three indices were evaluated: central processing unit capacity, cost, and performance. This evaluation confirms that the controller based on polynomial interpolation is the best option of the two examined methods due to the satisfactory balance between dynamic performance and cost. Despite the advantages of the controllers in being based on a lookup table and polynomial interpolation, the adaptive linear–quadratic–Gaussian has the benefit of not requiring an offline training campaign; however, the cost saving obtained with the lookup table controllers and polynomial interpolation controllers, due to the possible implementation on small-size microcontrollers with development tool simple and easy maintenance, will surely be desirable for a large number of deployed units, ensuring that those solutions are highly cost-effective. [ABSTRACT FROM AUTHOR]