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The recent developments in electric vehicle (EV) necessities the requirement of a human intervention free charging system for safe and reliable operation. Wireless power transfer (WPT) technology shows promising options to automate the charging process with user convenience. However, the operation of the WPT system is designed to operate at a high-frequency (HF) range, which requires proper control and modulation technique to improve the performance of power electronic modules. This paper proposes a dead-time (DT) integrated Pulse Density Modulation (PDM) technique to provide better control with minimal voltage and current ripples at the switches. The proposed technique is investigated using a LCC-LCL compensated WPT system, which predominantly affects the high-frequency voltage and current ripples. The performance analysis is studied at different density conditions to explore the impact of the integrated PDM approach. Moreover, the PDM technique gives better control over the power transfer at different levels of load requirement. The simulation and experimental analysis was performed for a 3.7 kW WPT prototype test system under different modes of operation of the high-frequency power converters. Both the simulated and experimental results demonstrate that the proposed PDM technique effectively enhances the efficiency of the HF inverter while significantly reducing output current ripples, power dissipation and improving the overall WPT system efficiency to 92%, and leading to a reduction in the power loss in the range of 10% to 20%. This leads to improved overall system control and performance. [ABSTRACT FROM AUTHOR]

This paper investigates the commutation transients of MOSFET and GaN FET devices in motor drive applications during hard-switching and soft-switching commutations at dead time operation. This study compares the switching behaviors of MOSFETs and GaN FETs, focusing on their performance during dead time in inverter legs for voltage source inverters. Experimental tests at various phase current levels reveal distinct switching characteristics and energy dissipation patterns. A validated simulation model estimates the experimental energy exchanged and dissipated during switching transients. The results demonstrate that GaN FETs exhibit lower overall losses at shorter dead times compared to MOSFETs, despite higher reverse conduction voltage drops. The study provides a quantitative framework for selecting optimal dead times to minimize energy losses, enhancing the efficiency of GaN FET-based inverters in low-voltage motor drive applications. Finally, a dead time optimization strategy is proposed and described. [ABSTRACT FROM AUTHOR]

Conveyor belts serve as the primary mode of ore transportation in mineral processing plants. Feeders, comprised of shorter conveyors, regulate the material flow from silos to longer conveyor belts by adjusting their velocity. This velocity manipulation is facilitated by automatic controllers that gauge the material weight on the conveyor using scales. However, due to positioning constraints of these scales, a notable delay ensues between measurement and the adjustment of the feeder speed. This dead time poses a significant challenge in control design, aiming to prevent oscillations in material levels on the conveyor belt. This paper contributes in two key areas: firstly, through a simulation-based comparison of various control techniques addressing this issue across diverse scenarios; secondly, by implementing the Smith predictor solution in an operational plant and contrasting its performance with that of a single PID controller. Evaluation spans both the transient flow rate during step change setpoints and a month-long assessment. The experimental results reveal a notable increase in production by 355 t/h and a substantial reduction in flow rate oscillations on the conveyor belt, evidenced by a 55% decrease in the standard deviation. [ABSTRACT FROM AUTHOR]

A space vector modulation (SVM) technique of a dual-inverter system for an open-end winding motor drive is described in this paper, where one inverter has a battery power source and the other has an only capacitor across the dc bus. The SVM must be achieved to operate the motor with field-oriented control and simultaneously to control the capacitor voltage at a constant value by using redundant switching states of the dual-inverter system. The control of the capacitor voltage is carried out by selecting a charging or a discharging mode in each redundant switching state, taking the instantaneous motor power factor into account. In addition, it is also required to reduce the error voltage pulses, which are generated in output multilevel voltage waveforms during the dead time. The compensation method of the existing dead-time scheme and the improved SVM sequence to reduce the error voltage vectors are proposed in this paper. The proposed methods are examined through several experimental tests and are confirmed to generate superior output voltage waveforms from the viewpoint of the measured total harmonic distortion and dv/dt. [ABSTRACT FROM AUTHOR]

To reduce the common-mode voltage (CMV) and eliminate the CMV spikes for two-level voltage source inverters (2L-VSIs), an improved model predictive control (MPC) based CMV reduction method is proposed in this paper considering dead-time effects. First, an improved voltage vector (VV) preselection strategy is proposed to reduce the CMV spikes caused by the dead time. Second, a new hybrid VV preselection strategy based on a delay compensation strategy and a modified current sector division strategy is proposed to completely eliminate the CMV spikes. As the proposed hybrid VV preselection based MPC strategy makes full use of the six nonzero VVs of the 2L-VSI, the current total harmonic distortions and ripples are reduced. The simulation and experiments are carried out to verify the effectiveness of the proposed strategy. [ABSTRACT FROM AUTHOR]

This paper proposes a 2-DOF preview feedforward sliding mode controller (PFFSMC), which has a combination of feedback and feedforward terms in the sliding surface, for controlling the multivariable process with dead time, for both set point tracking and disturbance rejection. The proposed controller is applied for the control of the Wood and Berry binary distillation column having the composition of top and bottom products. The performance of the 2-DOF PFFSMC is compared with that of the 1-DOF preview sliding mode controller. The proposed controller delivered better responses for set point tracking and for disturbance rejection. The performance of the proposed 2-DOF PFFSMC is compared with the other controllers reported in the literature and, it was found that there was a significant reduction in the settling time by more than 76%, without any overshoot in the closed loop response. The proposed controller was robust against ±5% parametric uncertainties in gain, time constant, and dead time when these uncertainties were considered alone and together. The stability of the proposed controller was verified using the Lyapunov stability criterion. [ABSTRACT FROM AUTHOR]

Centralized photovoltaic power station is an important part of building a new power system, whose power generation unit is the main equipment of the photovoltaic power station. Therefore, it is the basis of analyzing the harmonic characteristics of photovoltaic power generation to study the harmonic generation mechanism and influencing factors of power generation units and establish the harmonic equivalent model of photovoltaic power generation units. In this paper, firstly, the harmonic generation mechanism is analyzed from the aspects of sinusoidal pulse width modulation (SPWM) and dead time of inverter. Secondly, the correlation analysis of influencing factors of output power of photovoltaic power generation unit is carried out, and then the influence of output power on harmonics is analyzed. Thirdly, the harmonic characteristic model of photovoltaic power generation unit based on actual photovoltaic power station and influencing factors is constructed. Finally, the theoretical simulation of SPWM modulation and dead time is verified and analyzed, and the simulation results of harmonic characteristics are compared with the measured data. The results show that the harmonic characteristic of the centralized photovoltaic power station is mainly to generate high-frequency odd-order harmonics, which will generate extra high-frequency even-order harmonics when the irradiation is too high or too low, and cause interharmonics when the irradiance fluctuates on the DC side of the inverter. [ABSTRACT FROM AUTHOR]

Single photon avalanche diode (SPAD) is used in quantum detectors. Quantum detectors are widely used in quantum communication. The quality of these detectors strongly affects the optimal performance of the system. The quality of single photon detectors depends on various parameters, which are usually presented in the SPAD specification. If these detectors are made by the manufacturer or evaluated by the user, there is a need for a method to determine and check its main parameters. In this paper, a simple test setup for extracting some of important parameters has been designed and introduced, which can be used practically. These parameters include Dark Count Rate (DCR), Photon Detection Efficiency (PDE), AfterPulse Probability (APP) and Dead time. In the presented design, an FPGA chip is used to measure the parameters. FPGA is responsible for the simultaneous control of the single photon source and the detector. The presented methods specify how to extract the desired parameters. The characterization methods and detailed formulas presented in this paper calculate SPAD parameters.

This paper presents a centralised model predictive control strategy applied to biomass inventory control in sugarcane industries. Sugarcane industries are important renewable energy producers and an adequate inventory control of their feed material (biomass) can improve energy production. Simple linear discrete-time models with dead-time are developed to predict the controlled variable behaviour. Two layers are used in the controller, in the upper one performance is optimised by an linear programming (LP) algorithm and a multivariable generalised predictive controller (GPC) or multivariable generalised predictive controller with dead-time compensation (DTC-GPC) is used in the lower level. Simulation results in general show that the proposed controllers globally optimise the system behaviour and find an optimal ordering amount for keeping stock levels. In cases of plant/model mismatch DTC-GPC can have a significant and positive impact on the control of stock levels adding one more parameter for achieving minimised oscillatory performances (bullwhip effect). [ABSTRACT FROM AUTHOR]

This paper introduces the characteristics of the LYSO-SiPM-based receiver used in X-ray communication (XCOM). The X-ray signal receiving scheme based on a scintillator and photodetector is an important part of the XCOM system. However, the inherent characteristics of the scintillator and photodetector hinder the improvement of the performance of the X-ray signal receiver. Thus, this paper proposes a comprehensive analysis model for modeling the counting statistical characteristics of the LYSO-SiPM-based receiver, and analyzes the effects of the receiver's characteristics on the communication performance of the OOK-modulated XCOM system. Furthermore, the LYSO-SiPM pulse X-ray signal receiver is optimized, and its performance in the XCOM experiment is tested. The experimental results are consistent with the theoretical analysis trend, indicating that the proposed analytical model can be used for XCOM performance analysis and optimization. [ABSTRACT FROM AUTHOR]

The Proportional Integral Derivative Controller is a typical controller implemented frequently in many services and integrating the Smith predictor is an extremely useful control system structure for processes with dead time. This paper has evaluated two control schemes with the modified structures of the Smith predictor incorporating dead time compensators and conventional controllers for first order process with dead time. The disturbance response and the set point response for both the control schemes were decoupled from each other. Therefore two degrees of freedom control design was formulated, and hence the responses could be designed separately. The two control schemes have mainly two variables to be adjusted that decide the robustness and closed-loop behaviour. This paper also contains the calculation of various parameters that were used in each scheme. A comparison of the two control schemes along with the general Smith predictor control scheme was made using Simulink/Matlab. The conclusion is the second control scheme gave better response overall for the processes with dead time having dead time uncertainty and for the processes with dead time without dead time uncertainty. [ABSTRACT FROM AUTHOR]

SUMMARY This paper discusses the performance of compensation methods for dead-time voltage error in voltage-source grid-connection pulse-width modulation converters. The theoretical analysis in this paper reveals the relationship between the voltage error and the current ripples through the converter. The analytical results imply that the voltage error is strongly affected by the amplitude of the current ripples as well as the source power factor. This paper proposes a new compensation method which makes it possible to use two lookup tables to reduce the calculation time in the controller. The compensation characteristics are compared by using a 200-V 5-kW three-phase grid-connection converter. As a result, conventional approximation-based compensation methods exhibit an acceptable performance in a restricted power-factor operation range. In contrast, the turn-off transition-based compensation method and the proposed method have a good compensation performance all over the power factor. [ABSTRACT FROM AUTHOR]

This paper proposes a new adaptive dead time compensation method for dual three-phase permanent magnet synchronous motors with two sets of three-phase windings spatially shifted by 30 electrical degrees. The stator resistance and leakage inductance are the only 5th and 7th harmonic impedances in the dual three-phase motor, which leads to a more pronounced current distortion due to dead time in the dual three-phase motor than in the three-phase motor. Therefore, dead-time compensation has significant implications for the application of dual three-phase motors. In this paper, the minimum value tracking algorithm is used to adjust the compensation voltage amplitude adaptively, and the compensation voltages are added to the output reference voltage in stationary frames. The proposed computation method has some significant advantages, such as simple implementation without additional hardware, easy mathematical computations, and no offline experimental measurements. Simulation results are provided to validate the performance of the proposed method.

The paper is devoted to the study of the influence of pulsed instability of neutron generation on the efficiency of small transportable HMCs. Experimental diagrams of the spread of the neutron output per trigger pulse for PNG based on vacuum ATs with vacuum arc and laser sources of deuterons are analyzed. The possibility of approximating the probability density of the distribution with an accuracy of units of percent is established. Mathematical statistics methods have been used to obtain functions that allow correcting the HMC readings, taking into account the influence of the dead time of detection systems and the dispersion of the neutron output of PNG. [ABSTRACT FROM AUTHOR]

This paper discusses the voltage error caused by the dead time in voltage-source PWM converters. The theoretical analysis in this paper derives the nonlinear voltage error paying attention to the parasitic output capacitance in each switching device. The analytical result reveals that the turn-off current or the switching current ripple strongly affects the voltage error. In addition, it is clarified that the conventional compensation methods based on linear and three-level approximation are suitable under small and large current ripple conditions, respectively. A simple calculation method of current ripples in three-phase PWM converters is also developed to estimate the turn-off currents. Turn-off transition compensation method which is a new compensation method based on the analysis is developed and compared with three different conventional methods in experiments using a 200-V, 5-kW three-phase grid-connection converter. The proposed method exhibits a good compensation performance having a lower voltage THD than the conventional methods in all over the operating range. [ABSTRACT FROM AUTHOR]

Insertion of dead time in space vector pulse width modulation (SVPWM) causes phase voltage and current distortion or even zero-current clamping phenomenon, degrading the control performance of ac induction motor. In addition, analysis of distortion becomes more complicated due to the existence of parasitic capacitance in power switching device of voltage source inverter (VSI). This paper tries to make clear that how the parasitic capacitance influences VSI's output independently. First, an equivalent circuit of VSI containing parasitic capacitance is constructed. On that basis, mathematical expression of phase voltage distortion is derived from Kirchhoff's voltage law, Kirchhoff's current law, and charge and discharge characteristics of capacitance. Moreover, through the division of multiple zero-crossing regions in one phase current period, the difficulty of obtaining specific phase voltage error expressions is overcome. Second, to figure out the effect of parasitic capacitance, it is theoretically discussed in detail that how parasitic capacitances of different values affect phase voltage, current distortion, and zero-current clamping phenomenon. At last, simulations and experiments are carried out in which VSI with different parasitic capacitances is constructed by paralleling additional capacitors and with phase voltage feedback methods, the theoretical analysis can be verified. [ABSTRACT FROM PUBLISHER]

In this paper, a new nonisolated high-voltage-gain boost converter is proposed. The proposed converter is constructed by adding an additional inductor to a conventional three-level-boost (TLB) converter. When compared with the conventional boost and TLB converters, the proposed converter can achieve higher voltage conversion ratio with reduced voltage and current stresses in the switches. In particular, the proposed converter can reduce the losses of active devices by reducing the current of the switch compared to conventional converters, thus, can achieve high efficiency. In addition, the proposed converter automatically balances the output voltages for an unbalanced load without the need for any additional control strategy or auxiliary circuit. A 2-kW prototype converter was built and tested to verify performances of the proposed converter. [ABSTRACT FROM PUBLISHER]

The effect of inverter dead time on the inverter output voltage is well studied in the literature. This paper studies the effect of the dead time on the inverter input current. An expression for the switching-cycle-averaged inverter input current including the dead time effect is derived, which shows the dead time effect to primarily result in a reduction in the average value of the inverter dc input current. The effect of dead time on the input current is incorporated into the dc-link dynamic model of a diode-bridge-rectifier (DBR) fed voltage source inverter (VSI). A switching-cycle-average model of a DBR-VSI-fed induction motor is proposed, which considers the effect of dead time on both the ac output voltage and dc input current of the VSI. The proposed average model is used to study the light-load instability phenomenon in a 100-kW open-loop motor drive. The proposed model is shown to predict the region of oscillatory behavior (i.e., region exhibiting light-load instability) with better accuracy than existing average models. The proposed model also accurately predicts the dc-link voltage swing at such oscillatory operating points. While being comparable in accuracy in predicting the system dynamics, the proposed model is much more computationally efficient than the state-of-the-art switching model. The validity of the proposed average model is also confirmed by experimental measurements on a 100-kW induction motor drive. [ABSTRACT FROM AUTHOR]

The injected grid current of the voltage-controlled grid-connected inverter has serious distortion due to the low frequency harmonic components in the output voltage, which is resulted by the dead time of the drive signals of the power switches, and the distortion cannot be eliminated even when an output voltage closed loop is incorporated. This paper introduces a virtual series impedance to increase the output impedance of the grid-connected inverter only at the dominated lower harmonic frequencies; thus, the injected grid current quality can be improved and the dynamic performance of the grid-connected inverter is not deteriorated. Experimental results from a 6-kW single-phase grid-connected inverter confirm the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This paper presents a multimode digital controller with dead-time self-exploration (DTSE) for synchronous buck converters that simultaneously achieves high efficiency and a fast transient response. The automatic mode switching technique uses the duty-cycle command to determine multimode operation without sensing any current signals. The DTSE algorithm is used to minimize the steady-state duty-cycle command to maximize the converter efficiency. During load transients, a nonlinear control mode is employed to reduce the transient response. The proposed digital controller is fabricated in a CMOS 0.18-μm process. The experimental results for a 1.2-V output voltage show that the measured power efficiency is higher than 85% for a load range of 10-600 mA and that the measured transient response is improved by 28% compared to that of the traditional voltage-mode converter. [ABSTRACT FROM AUTHOR]

This paper proposes a control method for a dual active bridge (DAB) converter, which achieves both a reduction in the nonlinear transmission power error due to the dead‐time and a reduction in the inductor current with a three‐level operation. The nonlinear transmission power error is compensated by designing a zero current period in the inductor current with the three‐level operation. In addition, an inductor current reduction method for the three‐level operation is also proposed. In the nonlinear transmission power error compensation method, the inductor current is reduced by suppressing the circulating current by considering the zero‐current period to be the dead‐time. The validity of the proposed method is confirmed using a 2.0‐kW prototype. The experimental results show that the transmission power error is reduced by up to 85.1%. In addition, the inductor current is reduced by up to 64.1% and the loss is reduced by up to 58.6%. Moreover, the DC offset is eliminated by utilizing the voltage polarity reverse phenomenon in the voltage control. [ABSTRACT FROM AUTHOR]

This paper proposes an electrical parameter estimation method for permanent magnet synchronous motors (PMSMs) considering the voltage source inverter (VSI) nonlinearity. Accurate parameters are essential for high-performance control of PMSMs. Therefore, numerous studies have been conducted to obtain accurate parameters. However, the VSI nonlinearity causes voltage distortion, which causes parameter-estimation errors. To address this problem, this paper presents a solution using the double-frequency double-amplitude (DFDA) injection method based on the high-frequency (HF) injection method. The proposed method is a practical and novel method using simple mathematical calculations that takes into account VSI nonlinearity without using nonlinearity-compensation methods. It increases the accuracy and reduces the resistance-estimation step by simultaneously estimating the stator resistance and inductance. To demonstrate the efficacy and practicability of the proposed method, it was experimentally verified on a 400 W surface-mounted PMSM. The proposed method can simultaneously estimate the stator resistance and inductance with high accuracy within a short time and can, therefore, be applied to PMSM drives in various industries, such as robotics.

This paper analyzes the use of the voltage distortions in pulse width modulation voltage-source inverters caused by the inverter switching for islanding detection purposes. The nonideal characteristics of the inverters, mainly due to the dead time needed to have safe commutations, produce fundamental frequency-dependent harmonics (−5th, 7th, …) in the output voltage. These harmonic order are, in principle, an unwanted effect, as they reduce the power quality. However, they can potentially be used for islanding detection purposes. The physical principles of the method would be the same as for high-frequency signal injection methods that have already been proposed, but without the need of injecting a high-frequency signal, behaving, therefore, as a passive islanding detection technique. [ABSTRACT FROM AUTHOR]

Electronic power transformers (EPTs) have been identified as emerging intelligent electronic devices in the future smart grid, e.g., the Energy Internet, especially in the application of renewable energy conversion and management. Considering that the EPT is directly connected to the medium-voltage grid, e.g., a10 kV distribution system, and its cascaded H-bridges structure, the common mode voltage (CMV) issue will be more complex and severe. The CMV will threaten the insulation of the entire EPT device and even produce common mode current. This paper investigates the generated mechanism and characteristics of the CMV in a cascaded H-bridge EPT (CHB-EPT) under both balanced and fault grid conditions. First, the CHB-EPT system is introduced. Then, a three-phase simplified circuit model of the high-voltage side of the EPT system is presented. Combined with a unipolar modulation strategy and carrier phase shifting technology by rigorous mathematical analysis and derivation, the EPT internal CMV and its characteristics are obtained. Moreover, the influence of the sinusoidal pulse width modulation dead time is considered and discussed based on analytical calculation. Finally, the simulation results are provided to verify the validity of the aforementioned model and the analysis results. The proposed theoretical analysis method is also suitable for other similar cascaded converters and can provide a useful theoretical guide for structural design and power density optimization. [ABSTRACT FROM AUTHOR]

Numerous studies have been carried out to compensate or eliminate the dead-time effect. This paper analyzes the limitations of the previous compensation or elimination schemes. Then, a novel mixed pulsewidth-modulation scheme for dead-time elimination and compensation is proposed for the grid-tied inverter. The proposed scheme implements the dead-time elimination in most of the grid current fundamental period but switches to the conventional dead-time compensation around the zero-crossing point. In this way, a safe and efficient dead-time effect elimination method is achieved. Furthermore, this paper proposes to determine the switching point and the compensation direction by the grid current modulation function. Experimental results are given to demonstrate the validity and features of the proposed method. [ABSTRACT FROM AUTHOR]

In this paper the photon counting characteristics, the information rate and the bit error performance of single-photon avalanche diode (SPAD) arrays are investigated. It is shown that for sufficiently large arrays, the photocount distribution is well approximated by a Gaussian distribution with dead-time-dependent mean and variance. Because of dead time, the SPAD array channel is subject to counting losses, part of which are due to inter-slot interference (ISI) distortions. Consequently, this channel has memory. The information rate of this channel is assessed. Two auxiliary discrete memoryless channels (DMCs) are proposed which provide upper and lower bounds on the SPAD array information rate. It is shown that in sufficiently large arrays, ISI is negligible and the bounds are tight. Under such conditions, the SPAD array channel is precisely modelled as a memoryless channel. A discrete-time Gaussian channel with input-dependent mean and variance is adopted and the properties of the capacity-achieving input distributions are studied. Using a numerical algorithm, the information rate and the capacity-achieving input distributions, subject to peak and average power constraints are obtained. Furthermore, the bit error performance of a SPAD-based system with on-off keying (OOK) is evaluated for various array sizes, dead times and background count levels. [ABSTRACT FROM AUTHOR]

The actual standard for industrial technological processes and many other branches of automation is the PID-type controller. The problem of synthesis of such controllers has been studied in the literature in sufficient detail. The advantage of such controllers, which influenced on its wide popularity, is that it is a controller in which the automation system tuner can empirically change the numerical coefficients (from 1 to 4 depending on the controller type), based on the direct criteria of transient quality: the maximum deviation, overshoot, setting time, as well as on signs of instability. The problem of optimal synthesis of the PID-type controller based on typical models can be generally considered as solved. With the development of computer techniques and engineering mathematical software, the problem of synthesis of the optimal PID-type controller for any control object is solved by combining frequency criteria and optimization algorithms. Other approaches are also used, which are mainly designed for multivariable control objects. This paper solves the problem of synthesis of a discrete SISO (Single Input and Single Output) controller for a stable linear model of arbitrary order with dead time using engineering mathematical software. The main idea of the method is a modification of the classical Dahlin controller. The proposed controller has the following advantages: simple software implementation, no necessity to solve the optimization problem, high robustness, possibility to take into account all dynamics, and simple tuning procedure. A study of the controller's operation for typical forms of models was carried out and attention was paid to the problem of neutralization of stepwise disturbances when controlling integrating plants. [ABSTRACT FROM AUTHOR]

Surface nuclear magnetic resonance (NMR) is a geophysical technique for direct and quantitative detection of underground water sources. In recent years, with the application of lightweight instruments in tunnels and mines, coils with small dimensions and multiturn have been used for surface NMR. Increasing the coil turns increases the inductance and causes problems such as severe ringing, long dead time, and significant loss of early stage surface NMR signal. To address these problems, the cause of ringing in surface NMR instruments and the effect of ringing on the dead time are analyzed in this paper. The bipolar phase pulse (BPP) method is introduced to reduce the ringing based on the positive and negative superposition principle and therefore shorten the dead time. A surface NMR signal simulation test and a free-radical solution test are performed to verify the effectiveness of the BPP method. A comparison with technologies such as Q-SWITCH shows that the dead time of the surface NMR instrument decreases from 35 to 5 ms and that the signal-to-noise ratio (SNR) of the collected signal improves by 5 dB. [ABSTRACT FROM AUTHOR]