Dynamic Balancing Method Research Articles

A Dynamic Current Balancing Method for Paralleled SiC MOSFETs With Gate-Branch Full-Coupled Inductors

A Dynamic Current Balancing Method for Paralleled SiC MOSFETs With Gate-Branch Full-Coupled Inductors

Application of dynamic material balance to evaluate oil wells in Buzurgan oil field

The Material Balance Equation is a crucial tool utilized in reservoir studies to evaluate fluids and rock properties at static pressures. The Flowing and Dynamic Material Balance methods offer a significant advantage by avoiding the requirement to shut down wells, as they use flowing pressure instead of static pressure under constant or variable flow rates. The concept of "Dynamic Material Balance" involves converting the bottom hole flowing pressure at any point at any given time to the average reservoir pressure at that point. This allows for the use of classical material balance calculations and the development of classical material balance plots. In this study, the Dynamic Material Balance and Agrawal Type Curve techniques were used to estimate average reservoir pressures, initial hydrocarbon in place, and ultimate oil recovery for a well in the Mishrif reservoir, the main reservoir in the Buzurgan oil field. Many wells in this field experience problems such as high-pressure decline or continuous water production, necessitating ongoing evaluation. While the Dynamic Material Balance method focuses on boundary-dominated flow data, the Agrawal-type curve technique analyzes data from both transient and boundary flow periods. Agarwal decline curves were constructed using relationships of pseudo pressure normalized production, material balance pseudo time, and dimensionless variables in well-test analysis. The results from both methods showed comparable results with an absolute percentage error of (0.738) %, (3.07) %, and 5.7% for oil-in-place, drainage area, and average reservoir pressure, respectively. This strong correlation between the Dynamic Material Balance and Type Curve results indicates their accuracy and reliability.

Dynamic balancing method of power distribution and consumption tasks based on state iterative prediction and resource peaking shifting

In the context of the new power system, the widespread access to massive distributed new energy sources has led to the power distribution and consumption tasks characterized by multiple time scales, wide random distribution, and large demand differences, resulting in unpredictable resource peaks in the tasks computing resource demand curve. In view of this situation, a method of forecasting and dynamic balancing of computing resource demand for power distribution and consumption tasks based on state iteration was proposed: firstly, the tasks computing resource demand model was established under the analysis of the attributes and parameter demand of the power distribution and consumption tasks scenario. Secondly, on the basis of the short-term effectiveness prediction of the traditional Markov model, the first-order difference of the state is used for data training to track the state fluctuation, and the historical state and the predicted state are used for state iteration, so as to avoid the convergence of long-term prediction. Finally, a dynamic balancing model is established according to the time-scale characteristics of cyclical and non-cyclical tasks, and the optimal configuration of load imbalance is achieved through the identification and adjustment of historical data and burst data. The simulation results show that the improved Markov model based on first-order difference and state iteration has the short-term accuracy of the traditional model and the long-term traceability of data fluctuations. The dynamic balancing model can combine the characteristics of historical data and burst data to effectively reduce the imbalance of resource demand, and show good ability to cope with resource imbalance deviation.

Dynamic balancing of rigid rotors by the influence coefficient method

Applied to rigid rotors, the influence coefficient method is the most adaptable method for rotor dynamic balancing because it uses only experimental information. The sole requirement for balancing rotors with this method is that there exists proportionality between mass unbalance located at correction planes and vibration measured at measuring planes. Hence, the rotors only need to be described by correction and measuring planes. The sensitivity of the measuring planes compared to the correction planes determines the response of the amount of unbalance for a specified rotation speed. The paper aims to describe in detail the experiment for dynamic balancing of rotors to verify the influence coefficient method. The direct calibration on two-plane rigid rotor using this method showed that a significant reduction of unbalances can be obtained. The results can be helpful for the design and safety assessment of dynamic systems equipped with rotors for marine engineering. Keywords: Rotor dynamic balancing, influence coefficient method, residual unbalances, Discrete Fourier Transform

A novel rotor dynamic balancing method based on blade tip clearance measurement without the once per revolution sensor

The existence of the aeroengine casing, limited monitoring points, and multi-fault characteristics make obtaining the rotor’s vibration transmission characteristics challenging, resulting in difficulties accurately identifying the rotor unbalance. This paper utilizes a high-frequency composite sensor to monitor the engine’s blade tip clearance (BTC) and extracts unbalanced information from BTC signals for rotor dynamic balancing, while avoiding the need for the once per revolution (OPR) sensor. First, the vibration characteristics of the rotor-blade system under multi-fault conditions are investigated. Then, based on BTC measurement, a none OPR method and an unbalance identification method are proposed, in which the radial vibration of the blade tip in the BTC signals at different speeds is extracted and operated in the time domain to obtain the rotor unbalanced vibration, the signal is reconstructed, and cross-correlation analysis is used to accurately identify the magnitude and phase of the unbalanced signal. Finally, a rotor test bench is utilized for experimental verification. The results reveal that the dynamic balancing method based on the BTC signal can more precisely identify the rotor unbalance than the traditional rotor dynamic balancing method. The application of this technique will effectively improve engine health management and fault prediction.

Efficient task scheduling in cloud networks using ANN for green computing

SummaryRecently, there has been a growing emphasis on reducingenergy consumption in cloud networks and achieving green computing practices toaddress environmental concerns and optimize resource utilization. In thiscontext, efficient task scheduling minimizes energy usage and enhances overallsystem performance. To tackle the challenge ofenergy‐efficient task allocation, we propose a novel approach that harnessesthe power of Artificial Neural Networks (ANN). Our Artificial neural network Dynamic Balancing (ANNDB) method is designed toachieve green computing in cloud environments. ANNDB leverages the feed‐forwardnetwork architecture and a multi‐layer perceptron, effectively allocatingrequests to higher‐power and higher‐quality virtual machines, resulting inoptimized energy utilization. Through extensive simulations, wedemonstrate the superiority of ANNDB over existing methods, including WPEG,IRMBBC, and BEMEC, in terms of energy and power efficiency. Specifically, ourproposed ANNDB method exhibits substantial improvements of 13.81%, 8.62%, and9.74% in the Energy criterion compared to WPEG, IRMBBC, and BEMEC,respectively. Additionally, in the Power criterion, the method achievesperformance enhancements of 3.93%, 4.84%, and 4.19% over the mentioned methods.The findings from this research hold significant promise for organizations seekingto optimize their cloud computing environments while reducing energyconsumption and promoting sustainable computing practices. By adopting theANNDB approach for efficient task scheduling, businesses and institutions cancontribute to green computing efforts, reduce operational costs, and make moreenvironmentally friendly choices without compromising task allocationperformance.

Airy stress based nonlinear forced vibrations and internal resonances of nonlocal strain gradient nanoplates

This paper presents a novel investigation of nonlinear forced vibrations and internal resonance in nonlocal strain gradient nanoplates, taking into account in-plane motions. The study comprehensively models the nanoplate structure, employing Kirchhoff's plate theory, nonlocal elasticity theory, and strain gradient elasticity theory. The incorporation of the Airy stress function allows for the consideration of in-plane displacements. The large amplitude deformations in the nanoplate are described using the von Kármán geometric nonlinearity model, and the equations of motion are derived using the force-moment dynamic balance method. The coupled equations of motion are solved using the Galerkin scheme and a dynamic equilibrium technique. Detailed discussions are provided on the influence of nonlocal and strain gradient parameters on the nonlinear vibration response of the Airy stress nanostructure. Moreover, it is demonstrated that specific combinations of nonlocal and strain gradient parameters lead to various types of internal resonance (including two-to-one and three-to-one internal resonances), significantly affecting the nonlinear frequency responses of the nanoplate, resulting in rich nonlinear behaviours. This study contributes to the understanding of the complex dynamics of nanoplates subjected to external time-dependant loads and offers valuable insights for the design of diverse nanoplate systems, including graphene sheets, which are relevant to nanoelectromechanical systems (NEMS) applications.

Active Gate Driver for Dynamic Current Balancing of Parallel-Connected SiC MOSFETs

In high-power applications, parallel connection of discrete silicon carbide (SiC) MOSFETs is necessary to increase the current rating. However, the unbalanced dynamic current during switching transient may cause unequal power loss and thermal distribution, which is a great challenge in parallel applications. In this paper, a dynamic current balancing method based on a new active gate driver (AGD) is proposed to improve the current sharing. The principle of the AGD is based on <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">di/dt</i> feedback control and voltage controlled current source to adjust gate drive current of SiC MOSFETs. Therefore, the switching trajectory of the paralleled devices can be changed to achieve current balance. In addition, by using master-slave control strategy, the proposed AGD can be easily used for multiple paralleled devices. The double pulse tests are conducted to verify the effectiveness of the proposed AGD. For two paralleled devices, the turn-on and turn-off switching energy imbalances are reduced from 13.4% and 56.0% (12.1% and 52.9%) to 8.8% and 15.3% (8.0% and 8.8%) by the current source (current sink) circuit. For six paralleled devices, the degrees of turn-on and turn-off switching energy imbalances can be reduced from 21.8% and 16.1% to 11.8% and 7.8% by the proposed AGD. <fn fn-type="other" id="fn3" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This work was supported by Key-Area Research and Development Program of Guangdong Province under Grant 2021B0101310004, and the research program sponsored by Eaton. (<i>Corresponding author</i>: <i>Junming Zhang</i>) Y. He, X. Wang, S. Shao, and J. Zhang are with the College of Electrical Engineering, Zhejiang University, Hangzhou 310027, China (e-mail: ; ; ; ). </fn>

Design Method and Experiment of Virtual Dynamic Balance for Rotating Parts with Non-axisymmetry and Complex Surfaces

Design Method and Experiment of Virtual Dynamic Balance for Rotating Parts with Non-axisymmetry and Complex Surfaces

Research on the method of power grid investment considering the difference and common points of binomial coefficient and variation coefficient

In order to achieve multiple goals such as ensuring power security, stable operation, driving industrial development, and implementing the "carbon peak, carbon neutral" action plan, this paper builds a smart grid investment decision-making evaluation calculation method model, and expounds the derivative value of investment from an economics perspective. concept, constructs a multi-scenario-oriented derivative value investment criterion, and sorts out the smart grid investment method based on the promotion approach and industrialization method; puts forward the smart grid investment derivative value evaluation index system and its screening criteria; mixed binomial coefficient method and The coefficient of variation method constructs a subjective and objective fusion evaluation method of multi-objective dynamic balance. It has certain advantages in processing large-scale index data and can dynamically adapt to different evaluation scenarios and needs.

Mask-guided modality difference reduction network for RGB-T semantic segmentation

By exploiting the complementary information of RGB modality and thermal modality, RGB-thermal (RGB-T) semantic segmentation is robust to adverse lighting conditions. When fusing features from RGB images and thermal images, the existing methods design different feature fusion strategies, but most of these methods overlook the modality differences caused by different imaging mechanisms. This may result in insufficient usage of complementary information. To address this issue, we propose a novel Mask-guided Modality Difference Reduction Network (MMDRNet), where the mask is utilized in the image reconstruction to ensure that the modality discrepancy within foreground regions is minimized. Doing so enables the generation of more discriminative representations for foreground pixels, thus facilitating the segmentation task. On top of this, we present a Dynamic Task Balance (DTB) method to balance the modality difference reduction task and semantic segmentation task dynamically. The experimental results on the MFNet dataset and the PST900 dataset demonstrate the superiority of the proposed mask-guided modality difference reduction strategy and the effectiveness of the DTB method.

A new multi-disk shaft balancing method for rotating machinery using strain gauges

Unbalance is a major factor influencing rotating machinery vibration. In general, vibration problems caused by mass imbalance can be solved by dynamic balancing method. When dynamically balancing a flexible rotor, if the counterweight plane does not coincide with the unbalanced plane, it will cause the rotor to bend and deform, and the bending deformation will produce a new unbalance force. So, it is important to identify the unbalanced force on each plane. A method to solve this problem using strain gauges was presented. The equation to identify unbalance force at three or more planes of a shaft is set up. A series of tests were done on a rotor bearing rig. The tests show that unbalance weights and angles at different rotating speeds were identified with high accuracy. It is a new and effective method for multi-disk shaft balance.

Balancing of Motor Armature Based on LSTM-ZPF Signal Processing

Signal processing is important in the balancing of the motor armature, where the balancing accuracy depends on the extraction of the signal amplitude and phase from the raw vibration signal. In this study, a motor armature dynamic balancing method based on the long short-term memory network (LSTM) and zero-phase filter (ZPF) is proposed. This method mainly focuses on the extraction accuracy of amplitude and phase from unbalanced signals of the motor armature. The ZPF is used to accurately extract the phase, while the LSTM network is trained to extract the amplitude. The proposed method combines the advantages of both methods, whereby the problems of phase shift and amplitude loss when used alone are solved, and the motor armature unbalance signal is accurately obtained. The unbalanced mass and phase are calculated using the influence coefficient method. The effectiveness of the proposed method is proven using the simulated motor armature vibration signal, and an experimental investigation is undertaken to verify the dynamic balancing method. Two amplitude evaluation metrics and three phase evaluation metrics are proposed to judge the extraction accuracy of the amplitude and phase, whereas amplitude and frequency spectrum analysis are used to judge the dynamic balancing results. The results illustrate that the proposed method has higher dynamic balancing accuracy. Moreover, it has better extraction accuracy for the amplitude and phase of unbalanced signals compared with other methods, and it has good anti-noise performance. The determination coefficient of the amplitude is 0.9999, and the average absolute error of the phase is 2.4°. The proposed method considers both fidelity and denoising, which ensuring the accuracy of armature dynamic balancing.

A Dynamic Current Balancing Method for Paralleled SiC MOSFETs Using Monolithic Si-RC Snubber Based on a Dynamic Current Sharing Model

The dynamic current imbalance between paralleled SiC <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> s will cause unbalanced losses and reduce current capacity. The existing current balancing methods will make the circuit more complex or hard to design and implement. Hence, this article proposes a dynamic current balancing method by connecting monolithic Si- <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RC</i> snubber between paralleled <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> s, which maintains a simple circuit structure and is easy to implement. Balanced dynamic currents can be achieved by adjusting the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RC</i> snubber connecting location. Meanwhile, low voltage spike and low switching oscillation can be achieved by using <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RC</i> snubber. First, an analytical current sharing model is established for paralleled SiC <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> s. The key parameter affecting the balance of the drive circuit and then affecting the dynamic current sharing is obtained for the first time. Based on the conclusions of the model, this article then presents the current balancing method using <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RC</i> snubber. Then, a power module with monolithic Si- <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RC</i> snubber is designed, fabricated, and tested. Experimental results verify the current sharing model and the current balancing method. The current difference of the optimized module is reduced by more than 50% under different conditions. Finally, the effectiveness of this method in the module with more paralleled <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> s is verified.

Development of single measuring point overall balancing method based on multi-cylinder dynamic balance detection system

The combine harvester with multi-cylinder has a wide application in improving the operation efficiency. Therefore, as an important process in combine harvester, threshing operated by multi-cylinder usually makes the working structures suffer hit from the blockage of stones or materials. Consequently, the cylinders fail to guarantee the original balance. Several studies have been performed in this area, based on the dynamic balance method and vibration signal processing. However, most of them are not efficient for multi-cylinder. This study aims at developing an online dynamic balance detection system for multi-cylinder in combine harvester, in order to enhance the efficiency and accuracy of online dynamic balance detection. A multi-cylinder test rig is developed, and unbalanced vibration experiments under different working conditions are performed. The results show that the different measuring positions have different sensitivities to unbalanced mass. The vibrations will be transmitted through the frame, and coupled with each other. Under the multi-cylinder rotation, the vibration has strong randomness and poor convergence. For this purpose, the single measuring point overall balancing method is proposed. An adaptive multiple filter algorithm relying on the LabVIEW platform, is also proposed. Through phase relation between cylinders, the single measuring point overall balancing algorithm is developed. The comparison experimental results show that the proposed algorithm is more robust under the multi-cylinder rotation. The proposed method simultaneously installs sensors on the bearing seat of No. 1 tangential cylinder and balance 3 cylinders. The traditional method balance 3 cylinders separately change the sensor position. The effect of the proposed method is almost 76%, while that of the traditional balance method is almost 66%. For the multi-cylinder system, the single measuring point overall balancing method can efficiently improve the balance effect by 10%. Finally, it can be deduced from the experiment on the combine harvester that the accuracy of the proposed method reaches G3.9.

Transient dynamic balancing of the rotor system with uncertainty

The non-intrusive uncertainty quantification methods and the transient dynamic balancing method are proposed in this paper, which are combined for the first time to analyze the transient dynamic balancing of the rotor system with uncertainty. Uncertainties are described by multi-dimensional ellipsoid model (MEM) and quantified as the transient uncertain responses obtained by Monte Carlo Simulation (MCS) and Chebyshev interval algorithm (CIA), respectively. The transient dynamic balancing method is supposed to balance the rotor system by the transient uncertain responses and the variable system modal characteristics due to the uncertain parameters during acceleration. The simulation analysis and experimental tests of the single disc rotor system are carried out. The results show that the proposed uncertainty quantification methods can keep good accuracy in vibration prediction of the accelerating transient process. And the maximum deflection decrease range of the disc is 68.20–72.32% in experimental tests, verifies the effectiveness and reliability of the proposed balancing method in balancing the rotor system with uncertainty. The transient dynamic balancing of the uncertain rotor system will facilitate the on-site dynamic balancing process and will definitely improve reliability and safety of the rotor system during operation at high speed.

A High Accuracy Method for the Field Dynamic Balancing of Rigid Spindles in the Ultra-Precision Turning Machine

A High Accuracy Method for the Field Dynamic Balancing of Rigid Spindles in the Ultra-Precision Turning Machine

Wind resistance calculation of large rotary mesh antenna and its influence on dynamic balance precision

Due to the wind resistance which acts on the main reflector of large rotary mesh antenna, the correct balancing result of satellite antenna is difficult to be gotten in the ground dynamic balancing test. In order to solve this problem, the dynamic balance method of large rotary mesh antenna which is under the influence of wind resistance in both low pressure environment and standard atmospheric pressure environment on the ground is studied. Based on the theoretical analysis and the experimental data of two-dimensional flow around circular cylinder, a new method of the large rotary mesh antenna wind resistance calculation is proposed, according to the CFD analysis of the three dimensional flow field. Through the dynamic equivalent method, the distributed wind resistance acted on the main reflector of the mesh antenna in the rotating state is equivalent to the principal vector and principal moment of the action point in each quadrant, and then transformed into the eccentric mass on the distribution plane. It provides a feasible and innovative way to estimate the influence of wind resistance on the dynamic balance accuracy of large mesh antenna, so as to compensate the wind resistance effect. Combined with the ground dynamic balancing requirements of a certain type of satellite mesh antenna, the whole finite element model of the mesh antenna is established, the simulation of ground dynamic balancing test is carried out, and the influence of wind resistance on the ground dynamic balancing results of the antenna is analyzed in this study, which provides important data for compensating the influence of wind resistance and ensuring the on-orbit balancing accuracy of the antenna.

Investigation on transient dynamic balancing of the power turbine rotor and its application

In the dynamic balancing procedure of the rotor system, the unbalance is determined as a principal parameter which should be identified firstly. In actual engineering, the interference of external noise on the rotor is usually the main factor influencing the identification. In this paper, we focus on the unbalance identification of the power turbine rotor while the vibration response is influenced by signal interference during the balancing process in actual engineering. Fast Fourier Transform (FFT) and wavelet transform are used to analyze the collected original signal. Butterworth filter and Chebyshev type I filter are employed to test signal processing. The transient dynamic balancing method and the single plane influence coefficient method are used to balance the three balancing bosses of the rotor, and the balance efficiency is compared. The results show that, the signal fluctuation of boss 3 in high-frequency band is less than boss 1 and boss 2. Butterworth filter is more effective than Chebyshev type I filter in filtering the transient response data. The transient dynamic balancing method requires one test run without any trial-weights. More importantly, compared with the influence coefficient method, the transient dynamic balancing method has a better balancing effect.

Dynamic Material Balance Method for Estimating Gas in Place of Abnormally High-Pressure Gas Reservoirs

Abstract Determination of gas in place (GIP) is among the hotspot issues in the field of oil/gas reservoir engineering. The conventional material balance method and other relevant approaches have found widespread application in estimating GIP of a gas reservoir or well-controlled gas reserves, but they are normally not cost-effective. To calculate GIP of abnormally pressured gas reservoirs economically and accurately, this paper deduces an iteration method for GIP estimation from production data, taking into consideration the pore shrinkage of reservoir rock and the volume expansion of irreducible water, and presents a strategy for selecting an initial iteration value of GIP. The approach, termed DMBM-APGR (dynamic material balance method for abnormally pressured gas reservoirs) here, is based on two equations: dynamic material balance equation and static material balance equation for overpressured gas reservoirs. The former delineates the relationship between the quasipressure at bottomhole pressure and the one at average reservoir pressure, and the latter reflects the relationship between average reservoir pressure and cumulative gas production, both of which are rigidly demonstrated in the paper using the basic theory of gas flow through porous media and material balance principle. The method proves effective with several numerical cases under various production schedules and a field case under a variable rate/variable pressure schedule, and the calculation error of GIP does not go beyond 5% provided that the production data are credible. DMBM-APGR goes for gas reservoirs with abnormally high pressure as well as those with normal pressure in virtue of its strict theoretical foundation, which not only considers the compressibilities of rock and bound water, but also reckons with the changes in production rate and variations of gas properties as functions of pressure. The method may serve as a valuable and reliable tool in determining gas reserves.