Maximum Output Operation by Equivalently Field Weakening and Optimal Parameters of BLDC Motor

2012 ◽  
Vol 566 ◽  
pp. 170-181
Author(s):  
Komatsu Yasuhiro ◽  
Syed Abdul Kadir Zawawi ◽  
Yoshihiko Araki
Keyword(s):  
Direct Current ◽  
Optimal Parameter ◽  
Parameter Determination ◽  
Maximum Output ◽  
Optimal Parameters ◽  
Motor Torque ◽  
Field Weakening ◽  
Salient Pole ◽  
Torque Generation ◽  
Source Voltage

Permanent-magnet brushless direct-current motors are easy to maintain, compared with direct-current motors. Therefore, they are attracting attention. In this paper, the authors discuss a non-salient pole brushless direct-current motors. Usually, the quadrature armature current which contributes to torque generation is supplied in this motor. But, in this case that the source voltage cannot be increased by supplying the direct armature current, that is, equivalently field weakening, a quadrature armature current can be increased. Consequently, the motor torque increases. In the case that the load characteristics are settled, the motor torque can have a maximum Tm by adjusting a direct armature current. At this time the rotational speed and output are maximum also. Tm changes with the change of the motor parameters. Consequently, the motor parameters which maximize Tm are optimal. In this paper, the authors have clarified an optimal parameter determination method considering by the load torque-speed characteristics and, armature resistance by the power factor, and efficiency where the motor has optimal parameters and generates the maximum output. Furthermore, the theory obtained has been confirmed experimentally by the authors.

A Novel Nanogap Fabrication Technique Using Taguchi Method and Modified Particle Swarm Optimization

2012 ◽  
Vol 236-237 ◽  
pp. 118-122
Author(s):  
Te Sheng Li ◽  
Ling Hui Chen
Keyword(s):  
Particle Swarm Optimization ◽  
Taguchi Method ◽  
Optimal Parameter ◽  
Metal Layer ◽  
Particle Swarm ◽  
Optimal Parameters ◽  
Fabrication Technique ◽  
Swarm Optimization ◽  
Modified Particle Swarm Optimization ◽  
Metal Type

In this study, a novel nanogap fabrication technique is proposed. The technique is based on electron-beam lithography combined with rapid thermal annealing (RTA) to reduce the self-aligned nanogap on metal layer. The procedure running through systematic experimental design via Taguchi method and considering the critical factors such as metal type, Si thickness, RTA temperature, RTA time and initial nanogap dimension affecting the final nanogap dimensions was optimized. The experiments were conducted using Taguchi method and modified particle swarm optimization for setting the optimal parameters. The experimental results show that the most important factors in nanogap reduction were the metal type and the initial nanogap. The optimal parameter settings were metal type Pt on 50 nm Si/SiO2, 400°C, 60s and 43nm for initial gap. Experiment results found that the metal type Pt provided larger shrink ratio than that of Ni and nanogap down to 30 nm. It is also noted that the proposed approach was reproducible due to the confirmation experiments SNRs within the 95% confidence interval.

scholarly journals Optimal Operation Parameter Estimation of Energy Storage for Frequency Regulation

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1782 ◽  
Author(s):  
Sung-Min Cho ◽  
Jin-Su Kim ◽  
Jae-Chul Kim
Keyword(s):  
Energy Storage ◽  
Objective Function ◽  
Electricity Market ◽  
Optimal Parameter ◽  
Storage System ◽  
Optimal Operation ◽  
Electric Power System ◽  
Frequency Regulation ◽  
Optimal Parameters ◽  
Calculation Algorithm

This study proposes a method for optimally selecting the operating parameters of an energy storage system (ESS) for frequency regulation (FR) in an electric power system. First, the method allows the optimal objective function of the selected parameters to be set in a flexible manner according to the electric market environment. The objective functions are defined so that they could be used under a variety of electricity market conditions. Second, evaluation frequencies are created in order to simulate the overall lifespan of the FR-ESS. Third, calendar and cycle degradation models are applied to the battery degradation, and are incorporated into evaluations of the degradation progress during the entire FR-ESS lifespan to obtain more accurate results. A calendar life limit is set, and the limit is also considered in the objective function evaluations. Fourth, an optimal parameter calculation algorithm, which uses the branch-and-bound method, is proposed to calculate the optimal parameters. A case study analyzes the convergence of the proposed algorithm and the results of the algorithm under various conditions. The results confirmed that the proposed algorithm yields optimal parameters that are appropriate according to the objective function and lifespan conditions. We anticipate that the proposed FR-ESS algorithm will be beneficial in establishing optimal operating strategies.

scholarly journals Parameter Optimisation of Power Regeneration on the Hydraulic Electric Regenerative Shock Absorber System

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Peng Zheng ◽  
Ruichen Wang ◽  
Jingwei Gao ◽  
Xiang Zhang
Keyword(s):  
Shock Absorber ◽  
Optimal Parameter ◽  
Average Power ◽  
Structure Design ◽  
Performance Parameters ◽  
Optimal Parameters ◽  
Specific System ◽  
Proposed Model ◽  
Regenerative Shock Absorber ◽  
Prototype Design

With the increasingly prominent energy issues, regenerative shock absorber has attracted intensive attention in last two decades for the development of structure design. However, the researchers sometimes concentrate on conceptual designs without considering optimal parameter refinements. This paper proposes a regenerative shock absorber called the “hydraulic electric regenerative shock absorber (HERSA)” which includes an analytical regeneration performance parameters optimisation approach to promote the regeneration efficiency and regenerated power. The developed HERSA model is able to convert oscillatory motion into unidirectional rotary motion through the alteration of hydraulic flow while recovering power by a generator. The proposed model is also capable of obtaining the optimal parameters at certain condition, as well as providing the flexibility of different component combinations to match specific system need. The results demonstrate that the proposed model can effectively decide the optimal parameters in the system, and also the recoverable power can achieve average power of 331 W at 1 Hz-25 mm sinusoidal excitation in the system, which is approximately 65% efficiency. This study can be further used to guide prototype design in future study.

Parameter Optimization for Linear Quadratic Differential Games

1977 ◽  
Vol 99 (1) ◽  
pp. 58-62
Author(s):  
C. T. Leondes ◽  
T. K. Siu
Keyword(s):  
Differential Games ◽  
Parameter Optimization ◽  
Quadratic Differential ◽  
Necessary Conditions ◽  
Optimal Parameter ◽  
Small Region ◽  
Optimal Parameters ◽  
Numerical Techniques ◽  
Linear Quadratic ◽  
Linear Quadratic Differential Games

How should the minimizing player choose the values of certain parameters, if he wants to further optimize his payoff at the maximizing player’s expense? Hence what would be the greatest lower bound for the maximizing player’s payoff? To answer these questions, necessary conditions for parameter optimization for linear quadratic differential games will be derived. Iterative numerical techniques for determining optimal parameters will be developed. Search techniques which will locate a “small” region of uncertainty in which the optimal parameter must lie will also be discussed.

scholarly journals Multidataset Study of Optimal Parameter and Uncertainty Estimation of a Land Surface Model with Bayesian Stochastic Inversion and Multicriteria Method

2004 ◽  
Vol 43 (10) ◽  
pp. 1477-1497 ◽  
Author(s):  
Youlong Xia ◽  
Mrinal K. Sen ◽  
Charles S. Jackson ◽  
Paul L. Stoffa
Keyword(s):  
Land Surface ◽  
Root Zone ◽  
Model Simulation ◽  
Optimal Parameter ◽  
Land Surface Model ◽  
Heat Fluxes ◽  
Surface Model ◽  
Optimal Parameters ◽  
Stochastic Inversion ◽  
The Impact

Abstract This study evaluates the ability of Bayesian stochastic inversion (BSI) and multicriteria (MC) methods to search for the optimal parameter sets of the Chameleon Surface Model (CHASM) using prescribed forcing to simulate observed sensible and latent heat fluxes from seven measurement sites representative of six biomes including temperate coniferous forests, tropical forests, temperate and tropical grasslands, temperate crops, and semiarid grasslands. Calibration results with the BSI and MC show that estimated optimal values are very similar for the important parameters that are specific to the CHASM model. The model simulations based on estimated optimal parameter sets perform much better than the default parameter sets. Cross-validations for two tropical forest sites show that the calibrated parameters for one site can be transferred to another site within the same biome. The uncertainties of optimal parameters are obtained through BSI, which estimates a multidimensional posterior probability density function (PPD). Marginal PPD analyses show that nonoptimal choices of stomatal resistance would contribute most to model simulation errors at all sites, followed by ground and vegetation roughness length at six of seven sites. The impact of initial root-zone soil moisture and nonmosaic approach on estimation of optimal parameters and their uncertainties is discussed.

scholarly journals Enhanced Fault Current-Limiting Circuit Design for a DC Fault in a Modular Multilevel Converter-Based High-Voltage Direct Current System

2019 ◽  
Vol 9 (8) ◽  
pp. 1661 ◽  
Author(s):  
Kaipei Liu ◽  
Qing Huai ◽  
Liang Qin ◽  
Shu Zhu ◽  
Xiaobing Liao ◽  
...  
Keyword(s):  
High Voltage ◽  
Direct Current ◽  
Parameter Determination ◽  
Fault Current ◽  
Modular Multilevel Converter ◽  
Multilevel Converter ◽  
Hvdc System ◽  
High Voltage Direct Current ◽  
Operation Speed ◽  
Current Limiting

The main weakness of the half-bridge modular multilevel converter-based high-voltage direct current (MMC-HVDC) system lies in its immature solution to extremely high current under direct current (DC) line fault. The development of the direct current circuit breaker (DCCB) remains constrained in terms of interruption capacity and operation speed. Therefore, it is essential to limit fault current in the MMC-HVDC system. An enhanced fault current-limiting circuit (EFCLC) is proposed on the basis of fault current study to restrict fault current under DC pole-to-pole fault. Specifically, the EFCLC consists of fault current-limiting inductance L F C L and energy dissipation resistance R F C L in parallel with surge arrestor. L F C L reduces the fault current rising speed, together with arm inductance and smoothing reactor. However, in contrast to arm inductance and smoothing reactor, L F C L will be bypassed via parallel-connected thyristors after blocking converter to prevent the effect on fault interruption speed. R F C L shares the stress on energy absorption device (metal oxide arrester) to facilitate fault interruption. The DCCB requirement in interruption capacity and breaking speed can be satisfied effortlessly through the EFCLC. The working principle and parameter determination of the EFCLC are presented in detail, and its effectiveness is verified by simulation in RT-LAB and MATLAB software platforms.

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