Input Voltage Waveform Research Articles

Optimizing dialysis water treatment based on medical planning requirements

This paper introduces a new approach to improving hemodialysis and peritoneal dialysis processes. This maintains compatibility between the water treatment unit and active dialysis machines. Identification of different deviations in the patient’s requirements to classify the suitable flow rate (FR) of the pure water can be created through an Adaptive Neuro-Fuzzy Inference System (ANFIS). Four types of categories are classified: quarter load, half load, three-quarter load, and full load. This includes two main steps: identifying the dialysis categories with patients and measuring the suitable FR for each category. The effective FR of water was computed to indicate how the number of pumps rose as the number of patients treated within the dialysis unit increased. The introduced prediction method was tested against artificial neural networks to predict alum doses (ANN-AD) method, artificial intelligence as a combinatorial optimization strategy (AN-COS) using peach-palm waste in a solid-state fermentation environment, expert system applications (ESA) in chronic kidney disease management (MDSSs), prescription optimization for automated peritoneal dialysis (BCPH). In this work, pumping system parameter estimation was utilized to assess the performance of the introduced systems based on input voltage, input current, rotor speed, and electromagnetic torque waveforms of the pumping drive. This method uses the ANFIS algorithm to construct a high-performance pumping system to evaluate and predict the flow rate of dialysis machines based on input–output estimates. The flow rate values for each patient in critical care units can be controlled by the presented algorithm according to the time of dialysis. A good predictive model based on integrating the experience and decision making of medical planners was implemented. The proposed method not only improves accuracy but also saves time in the dialysis unit. The presented fuzzy classifier uses the ratio of the number of predicted true positives and false positives to the total number of anticipated positives. The simulation results show that the proposed technique can be successfully used to classify the suitable FR of the water according to the hemodialysis load. One of the advantages of the presented technique is the ability to predict the value of FR in real time with reliability, low computational complexity, and a high accuracy of 98.01%, which simplifies the dialysis process for many patients while at the same time leading to improved performance of hemodialysis. The presented method can be implanted in online FR estimation and analysis hardware for hemodialysis, is easy to calculate and run in real time, minimizes hemodialysis costs, and saves run time.

Comparative Analysis between Dynamic Voltage Restorer and PWM-Switched Autotransformer in Voltage Sag Mitigation

This research aims to address the problem of voltage sag, which is a significant power quality issue in power systems. Voltage sag can lead to power transmission and distribution line tripping and cause damage to electrical equipment. Various voltage sag mitigation devices have been developed to reduce the impact of voltage sag. In this study, we analyze the effectiveness of three types of voltage sag mitigation devices under different voltage sag conditions: three-phase fault, multi-phase fault, and energizing transformer inrush current. The three types of mitigations analyzed are Dynamic Voltage Restorer (DVR) with Park's transformation, DVR with Artificial Neural Network (ANN) controller, and PWM-switched autotransformer with Proportional-Integral (PI) controller. The simulation results using MATLAB demonstrate that all voltage sag conditions have been mitigated except for PWM-switched autotransformer during voltage sag caused by energizing transformer inrush current due to limitations of the PI controller scheme. Based on the analysis of input and output voltage waveforms, three-phase voltage magnitude before and after mitigation, and Total Harmonic Distortion (THD) value after mitigation, DVR with ANN controller is identified as the most effective voltage sag mitigation device, followed by DVR with Park's transformation and PWM-switched autotransformer.

A multi-level rectifier with voltage balancing capability for EV charging

ABSTRACT In two-stage electric vehicle (EV) battery chargers, ac-dc conversion stage contributes significantly in determining the power quality. At this stage, multilevel rectifiers (MLRs) featuring switches with lower voltage rating and better input voltage waveform quality can be adopted. However, balancing capacitor voltage in MLR is an important challenge. In this paper, a single-phase five-level power factor correction (PFC) rectifier with self-balancing capacitor is implemented for EV battery charging. The complimentary switching scheme adopted for rectifier reduces number of gate driver circuits and ensures capacitor voltage balancing. The rectifier shows added benefit of reduced voltage stress across switches and not requiring an external filter at the dc side as the load is parallelly connected with one of the capacitors. The operating principle, control strategy, modulation technique and design features of the implemented five-level rectifier is discussed in detail. The implemented control scheme enhances rectifier performance by establishing precise output voltage regulation during load fluctuations while maintaining unity power factor at input side. The five-level rectifier is validated experimentally and compared with other existing multilevel and non-multilevel rectifier topologies. The peak efficiency of 93.8% is achieved at 2 kW of output power.

Cancellation of Harmonics in the Magnetic Field Leakage From Inductive Power Transfer Systems

Harmonics in the magnetic field leakage from inductive power transfer systems can influence existing wireless communications and nearby electronic devices. To overcome this problem, we designed an input voltage waveform at the transmitter to cancel the harmonics in the field leakage from both the transmitter and receiver. This design was achieved by analyzing the harmonics in the circuit based on the formulations of the voltage at the input of the full-bridge rectifier and the harmonics in the magnetic field leakage. To validate the effect of the proposed method, we conducted circuit simulations and experiments that confirmed that the proposed method reduces the harmonics in the magnetic field leakage by up to 14.4 dB.

A Novel Single/Multiple Output Multilevel Buck Rectifier for EV-Battery Charging

An electric vehicle (EV) charging system is usually implemented in two stages: a power factor correction (PFC) rectifier stage, followed by a DC-DC converter. For such power conversion, multilevel rectifiers (MLRs) offer advantages compared to a two-level rectifier, such as reducing voltage ratings of power switches and yielding high-quality input voltage waveform. In MLRs, one of the most challenging aspects is balancing the capacitors’ voltages. This article proposes a self-balancing five-level PFC rectifier with the possibility of single/multiple outputs. The proposed rectifier performs buck operation and offers a wide output voltage regulation, which is suitable for EV battery charging. The five-level operation of proposed buck rectifier with continuous conduction mode (CCM) leads to elimination of the inductive filter on the DC side and the capacitive filter on the AC side. This article presents the operating principle, modulation strategy, closed-loop control and experimental validation of the proposed topology.

Research on Inverter Side Control of Power Grid Simulator Based on Active Disturbance Rejection and Repetitive Control

To track the input voltage waveform quickly and accurately, and sort out waveforms on the power grid simulator, a control strategy is proposed. The first loop use repeated control (RC) and PI Control composite control, and the voltage inner loop is controlled by a first-order linear self-disturbance rejection controller (ADRC). A suitable inverter topology is also designed. To improve the performance of the proposed controller, the bandwidth method is selected to adjust the observer bandwidth. In view of the frequency adaptability of inverters on the inverter side, the output voltage imbalance is suppressed by improving the repetitive control and the tracking accuracy is improved. The simulation results indicate the controller has the ability to track the waveform quickly and accurately. In addition, the waveform jitter is effectively suppressed.

Power supply circuit model and sliding mode control of supercritical unit boiler system commissioning

AbstractIn the process of power control and commissioning of supercritical unit boiler system, there are some problems such as large steady‐state error and slow response speed. In order to optimize the control performance of supercritical unit boiler system, the power supply loop model and sliding mode control method of supercritical unit boiler system debugging power supply are proposed. Firstly, the power supply circuit model is established according to the data of voltage doubling rectifier circuit, inverter circuit, high frequency transformer and LC resonant circuit. Secondly, the capacitance voltage value and the inductance current value are calculated in the power supply circuit model. Finally, based on the numerical results, a terminal sliding mode controller and a linear sliding mode controller are established to complete the double closed‐loop terminal sliding mode control and realize the power control of the debugging power supply. The experimental results show that when the input voltage is 50 V and the current is 14 V, the input voltage and current waveforms remain stable. When the input voltage is between 40 and 50 V, the change of switching frequency is small, only increasing from 22 to 26 kHz. The steady state of the power supply is high, and when the input voltage increases, the DC offset is 21.2. The convergence time in the calculation process is less than 200 ms. The instantaneous change of inductance is 0.7 A. The steady‐state error is less than 0.005 V. The output voltage distortion rate is less than 4%. It is proved that this method has strong control performance in the supercritical unit boiler system.

Analysis and Experimental Validation of Single-Phase Cascaded Boost AC–AC Converter with High Voltage Gain

This article presents a single-phase cascaded AC–AC converter with boosting capability for power-quality issues. A high voltage gain can be obtained based on the number of cascaded units. The basic construction of one unit in the cascaded connection requires only two four-quadrant switches with a low-voltage rating. The performance features for the topology are a unity power factor that is close to unity on the input side, high steady-state performance, and fast dynamic response. The operation modes and mathematical model for the topology are presented. An appropriate PI-based control method/strategy is created, so the converter may continue to run while attaining the desired voltage gain, even if one of the cascaded units fails. The control circuit’s ability to maintain the continuity of matching the input current waveform with the input voltage waveform allows a decrease in the THD with different operating conditions. Moreover, the ability to solve a dead time problem carried out by the control circuit leads to a reduction in voltage stress. The effectiveness and robustness of the proposed technique were demonstrated via a computer simulation using MATLAB/Simulink. Moreover, an experimental setup for the system was built in the laboratory to validate the practicability of the system, which was tested under different conditions. The good agreement obtained between the theoretical and experimental results endorses the validity of the designed circuit.

A Bidirectional Five-Level Buck PFC Rectifier With Wide Output Range for EV Charging Application

AC-to-DC conversion is integral to the two-stage charging interface of electric vehicle (EV) batteries. For such chargers, the use of multilevel rectifiers (MLRs) reduces voltage ratings of power switches, while achieving a high-quality input voltage waveform. Balancing of capacitors in MLRs, however, is an important challenge. In this work, a power factor correction (PFC) five-level rectifier with self-balanced switched capacitors is proposed. Each leg of the presented topology comprises five power switches and one switched capacitor, where the voltage ratings of power switches are equal to the output dc voltage. It does not require an additional filter capacitor on the dc side, as the load appears in parallel always with a switched capacitor of one of the legs. The five-level operation with continuous conduction leads to the elimination of the capacitive filter on the ac-side and inductive filter on the dc-side. This article presents the operating principle, modulation strategy, closed-loop control, and design aspects of the proposed rectifier. The proposed topology is validated through experimental results and a comparison is made with other topologies. Following three features of the proposed topology make it suitable for EV battery charging applications—buck operation with a wide output regulation, the possibility of bidirectional flow of power needed for vehicle-to-grid systems, and easy realization of its three-phase version by simply adding one more leg. These features too have been demonstrated with experimental results.

DPWM 기법을 적용한 비엔나 정류기의 L 필터 설계

This paper proposes the L-filter design method of Vienna rectifier with the DPWM(Discontinuous Pulse Width Modulation) method for satisfying the desired input current THD(Total Harmonic Distortion) specification. The input voltage waveform of Vienna rectifier with DPWM method is analyzed in this paper. The input current ripple is decided by the voltage applied to both end-points of the L-filter, which is voltage difference between the gird voltage and the input voltage of Vienna rectifier. In addition, the RMS(Root Mean Square) value of the input current ripple is derived by using on the waveform of input current ripple. In this paper, the RMS value of the input current ripple is used to design the L-filter satisfying the current THD specification of Vienna rectifier with DPWM method. The effectiveness of the proposed L-filter design method for Vienna rectifier with the DPWM method is verified through simulations and experiments.

An Efficient Battery Charger Control Scheme for Electric Vehicles

This work suggests a practical control scheme for a battery charger for an electric car that employs a cascade of buck converters and symmetrical bridge-less power factor-corrected converters. Both converters are increasingly common in the industrial sector thanks to their high efficiency, low price, and small size. The entire battery charging mechanism is made substantially more efficient by integrating the two converters. Furthermore, at any input voltage, this charger's design can deliver the correct battery current and voltage without ripple. In order to achieve a unity input power factor and zero input current harmonic distortion, the proposed control approach employs duty ratio feed-forward control technique in both the current and voltage control loops. In addition, a phase-locked loop (PLL) block establishes the current loop's reference, producing a pure sinusoidal input current despite the input voltage waveform's distortion. The viability and utility of the suggested approach are demonstrated using simulation and experimental data with an 110V/60Hz ac line input and a 1.5kW-72V dc output of the battery charging system.

Industrial Power Control by Integral Cycle Switching Without Generating Harmonics

This project is intended to attain vital cycle switching – a technique to get rid of the complete cycle, cycles, or fractions of cycles of an AC signal. It is a renowned and aged technique of managing AC power, principally across linear loads for instance heaters brought into play in electric oven. However, the concept of achieving the cycle stealing of voltage waveform by the use of Arduino can be very precise as per the program written in Arduino C language so that the actual time-average voltage or currently experienced at the load is proportionately lower than the whole signal if applied to the load. In this project, we are using a comparator for zero crossing detection which is fed as an interrupt to the Arduino Here, delivers the output based on the interrupt received as the reference for generating triggering pulses. Using these pulses, we drive the Opto-isolators for triggering the TRIAC to achieve integral cycle control as per the input switches interfaced to the microcontroller. In place of a linear load to be used in the output, a series motor or lamp can be used to verify the output. One side effect of utilizing this scheme is an imbalance in the input current or voltage waveform as the cycles are switched on and off across the load. A lamp is provided in this project in place of a motor for demonstration purpose. The project output with a lamp appears to be a simple project of lamp flickering but the real objective is to verify in a CRO/DSO ,whether at the random switching also the load switches on at zero cross of the waveform or not. The power supply consists of a step-down transformer 230/12V, which steps down the voltage to 12V AC. This is converted to a DC using a Bridge rectifier. The ripples are removed using a capacitive filter, and it is then regulated to +5V using a voltage regulator 7805, which is required for the operation of the microcontroller and other components. Furthermore, this project can be enriched by using a feedback mechanism to automatically maintain the desired output to the load by appropriate cycle stealing

PowerCog: A Practical Method for Recognizing Power Quality Disturbances Accurately in a Noisy Environment

Currently, with the growing applicability of nonlinear electrical devices, power quality disturbances (PQDs) often occur in power systems. Previous works usually extracted statistical features from electrical signals manually and constructed classifiers with traditional machine learning methods for PQD monitoring. Furthermore, noisy tags or unlabeled data (different from noisy signals) are usually ignored in the traditional training stage, and these methods fail to meet the high accuracy and automation demands of real-world scenarios. To overcome the shortcomings of existing methods, this article proposes a practical method called PowerCog for accurately recognizing PQDs in noisy environments. First, an input voltage waveform signal is divided into several intrinsic mode functions by an empirical wavelet transform, and these functions are then aligned into columns to form a matrix. Second, tritraining is utilized for label refactoring to improve the generalization ability of the model in a noisy environment. Then, an optimized convolutional neural network structure combined with principal component analysis is deployed to extract and select the universal features automatically. Finally, a support vector machine classifier is constructed to recognize PQD patterns. Several comparative experiments are performed to verify the effectiveness and accuracy of PowerCog in complex environments.

Soft-Switching Current-Source Rectifier Based Onboard Charging System for Electric Vehicles

In this article, a novel soft-switching current-source rectifier (CSR) based bidirectional on-board charger (OBC) system is proposed for electric vehicles (EVs) comprising multiple battery sets. Besides the CSR's inherent advantages of higher-quality input voltage waveforms, enhanced short-circuit-current tolerant capability and long lifetime of dc choke, the cascaded configuration of dc choppers can implement the higher dc-link voltage with multiple low-voltage battery sets, and the low-voltage devices can be used. With the auxiliary resonant circuit in dc link, the soft-switching operation can be achieved for all power switches in the proposed power conversion circuits. Moreover, the high dv/dt caused by high-speed switching silicon carbide devices can be reduced with the capacitor in the auxiliary circuit. The collaborative operation strategy is proposed for the CSR and the dc choppers, which enables reduction of switching frequency of dc choppers and current ripple in dc link simultaneously. The experimental results are presented to verify the performance of the proposed the OBC system.

Frequency-Dependent Bearing Voltage Model for Squirrel-Cage Induction Motors

This work describes a frequency-dependent bearing voltage model for squirrel-cage induction motors. Previous researches related to bearing voltages commonly considered the bearing voltage ratio (BVR) as a constant. However, it is important to analyze the frequency-dependent behavior of BVR when dealing with systems excited by high switching frequency PWM voltages. First, we measured the BVR characteristic for a 1.5-kW test motor. The measurement data shows that, in the mid-frequency range (100 kHz to 6 MHz), the BVR values are smaller than the conventional low-frequency constant value, and at higher frequencies, the BVR value increases above the low-frequency value. Considering this BVR characteristic, an equivalent circuit has been built and analyzed from the perspective of BVR. The proposed equivalent circuit has been verified by comparing simulation data with measurement data. Based on the analysis results of the equivalent circuit, a parametric study was done to examine the effects of motor system parameters on bearing voltage. For the study, variations of the bearing voltage on the changes of the input voltage waveforms and the winding-to-stator capacitance are analyzed by using measurement and simulation data.

Preliminary Study of Harmonic Generated by Household Appliances

This paper is preliminary study with focused on the harmonics generated by household appliances. There are only several household appliances that considered in this paper are television set, laptop computer and compact fluorescent lamp (CFL). To measure the input current, the measurement equipment was installed at the input side of equipment under the test. The important parameters that have been recorded are individual harmonic currents, total harmonics distortion, power factor, input current and input voltage wave form. From the measurement results, television sets, laptop computers and CFLs have been found generate the THDi of 177%, 273.66% and 154.2% respectively. If it is widely used in residential areas, it is likely that there will be increased harmonic distortion in the electric power distribution system. Because this research is still in its early stages, at the end of this research it will be known how much harmonics is generated by the load in the residential area. If amount of harmonics generated by the housing load that exceeds the limit, so the next step of this research a harmonics filter design will carried out.

Waveform optimization of a two-axis smooth impact drive mechanism actuator

This paper presents a data-driven method for waveform optimization of a two-axis smooth impact drive mechanism (SIDM) actuator. The actuator was constructed by two piezoelectric elements (PZTs) perpendicularly fixed to an L-shaped base for two-axis positioning. An XY stage was designed and constructed by assembling the two-axis SIDM actuator. The XY stage could position long motion ranges of several millimeters with nanometer-level resolution, and the size was confined to be 20 mm (X) × 20 mm (Y) × 4.5 mm (H). The data-driven method based on the long short-term memory (LSTM) neural networks was used to predict the optimum input voltage waveform of the actuator. With the optimized input voltage waveform, it was verified that the maximum velocity of the stage could be improved about two times.

Soft Haptic Actuator Based on Knitted PVC Gel Fabric

An electroactive and actuator made of knitted polyvinyl chloride (PVC) gel fabric is proposed herein. This haptic actuator consists of an upper layer, a lower layer, and fabric made by twisting long and slender PVC gel strings. The PVC gel fabric changes its shape according to the input voltage waveform, and exerts an electrostatic force between the upper and lower layers. When the applied voltage is removed, the PVC gel fabric rapidly restores to its initial configuration. Consequently, these effects generate vibrations that are sufficiently strong for human perception. In this paper, we conducted quantitative experiments to investigate the performance of our soft haptic actuator using an accelerometer and a laser scanning vibrometer. Furthermore, we performed a perceptual evaluation and the results indicate that our proposed actuator can stimulate the human skin with sufficient perceptual strength.

Study of the standard sine wave frequency conversion power supply based on analog and digital integrated control

In this article, a standard sine wave frequency conversion power supply based on analog and digital integrated control is proposed. First of all, the article introduces the topology structure and principle involved in this frequency conversion power supply. The system of frequency conversion power supply was designed based on the DSP2812[1] made by TI company. Next, it is stated that the method of analog-digital combination control simplifies the inexact algorithm, under the digital control, of calculating the carrier wave and the PWM driving signal of power device generation at the point of modulation wave intersection. In addition, it is also stated that the analog-digital integration control is equipped with a good performance in dynamic control response and a harmonic content that can effectively drop down the output voltage of the controller; the analog-digital integration control can realize the required motor control performance at a low cost, improve the operation efficiency of the motor, and suppress various secondary harmonic currents of the motor. At the end, the voltage and the input waveform of the electric currents of the system are under analyzed through a test simulation experiment on the power source of the variable frequency power supply system; at the same time, the input voltage waveforms corresponding to different frequencies are also involved in discussion, while the corresponding harmonic waves are analyzed.

A push-mode piezo inkjet equivalent circuit model enhanced by diaphragm displacement measurements

This paper reports on ways to better predict droplet ejection velocity of push-mode piezo inkjet technology by upgrading the conventional equivalent circuit model. Calculation results from the traditional model imply that the driving pulse width conditions without ink ejection only periodically exist in the pull-push piezo driving mode. However, ink ejection is actually observed under any pulse width condition. The displacement of the diaphragm with respect to the piezo element input voltage waveform was measured with a highly accurate capacitive displacement gauge to correct for the difference between the actual measurements and calculations. The equivalent circuit model was then modified so that the measured diaphragm residual oscillations could be expressed. We presumed that an actual inkjet printhead contains an effective spring oscillation component, effective actuator mass, and damping component larger than that used in conventional equivalent circuit model calculations. We demonstrated that the difference between the calculated results and actual measurements could be reduced. Modifications to equivalent circuit model are based on the addition of an effective mechanical spring oscillation component having the same function as the ink chamber compliance, an increase in actuator inertance corresponding to the mass of the actuator, and an effective resistance element expressing a damped oscillation.