Measurement, Control, and Automation

ANN-Based Model for Daily Solar Radiation Prediction with A Low Number of Hidden Neurons And Optimal Inputs

2021-03-09T03:37:54+00:00

Solar radiation prediction has been the focus of many studies over the past years due to its usefulness for clean energy generation through photovoltaic (PV) systems. The prediction result is important for both standalone and grid-connected PV systems as it is used for the design of these systems, for making power dispatching plans in hybrid systems, as well as for potential future PV system feasibility. In this article, an Artificial Neural Network (ANN)-based model for daily global solar radiation prediction is developed. This model is trained with a back-propagation training algorithm and make prediction using meteorological variables as inputs. While keeping a good accuracy level, the model is built using a low number of neurons in the hidden layer of the ANN. Therefore, the proposed model is simpler as compared to many existing models. First, the minimum and the maximum numbers of hidden neurons are calculated (page 4). Second, simulations based on a trial-and-error method can show us the good number of hidden neurons. A simple model is preferred than a complex one when the performance is same or almost. In addition, a simple model is easy to understand and to implement and also allows quicker modifications when needed.

Tension control for multi-span web transport systems with roll inertia uncertainty compensation using RBF neural network

2021-05-11T06:33:58+00:00

A roll-to-roll system which is a flexible multi-shaft web transport system is very common in the industries such as paper, metal processing, polymers, fabric and so on. However, web tension and speed control of the roll-to-roll system are difficult because of the nature of the system including multi-input multi-output, time variance, and nonlinearity. In this paper, modeling and controling problems of the multispan roll to roll systerm are investigated. From the governing equations of the web dynamics, a backstepping based controller with Neural RBF for web velocity and tension regulation is developed. The neural network design is based on the Radial Basis Function network that estimates the uncertainty of roll inertia. Simulation results show the effectiveness of the proposed approach.

Experimental Validation for Pneumatic Artificial Muscles using Fuzzy PID Control

2021-07-05T11:13:26+00:00

Along with the remarkable development of science and technology, recently, robot application in life is quite popular such as robots interacting with humans, rehabilitation robots, etc. Therefore, the pneumatic artificial muscle (PAM) has been studied for application in robot manufacturing. However, the high-performance control system construction is difficult due to the non-linear structure of an artificial muscle. With a classic Proportional-Integral-Derivative (PID) control, the trajectory tracking performance is not high because a fixed set of PID parameters does not solve the enhancing performance problem. Therefore, in this paper, a fuzzy PID control (FPIDC) for a PAM is presented to improve the trajectory tracking performance. The efficiency of the proposed controller has been verified by experiment under different conditions.

Modeling and Control of a Novel Structure of the 4DOF-Hybrid Magnetic Bearings

2021-05-17T07:04:39+00:00

This paper presents the modeling and control of a Novel Structure of the four Degrees of Freedom (4DOF) Hybrid Magnetic Bearings (HBMs) with a rigid rotor. In which, the centralized PD control is applied to control the HBM at its center coordinates. First, The magnetic force is calculated through the equivalent magnetic circuit, the position stiffness and the current stiffness are identified by linearizing around the operating space. From there, the mathematical model of the HMB is introduced. The dynamic properties of the parallel and inclination mode of the rotor were analyzed to design a centralized PD controller. Finally, the proposed control strategy was verified by simulation. The results indicate that the HBM not only work stably but also ensures independent control of the rotor's translation and inclination.

Modeling the selectivity of SAW filter with single phase unidirectional transducer based on FEM and equivalent circuit model

2021-06-25T08:32:40+00:00

This study uses FEM and Mason simulation methods to evaluate the selectivity of the bandpass SAW filter with SPUDT structure. The results show that when changing the width of the asymmetric finger of the IDT, the selectivity of the filter is changed. Specifically, the asymmetric finger width of 15 µm showed better selectivity than the equivalent structure with the asymmetric finger width of 5 µm. The results are consistent with the explanatory theory of previous research methods. Besides, the application of the SPUDT structure model test to the Masson model has shown an improvement in the selectivity of the SAW filter

Using an active rectifier on the secondary side to control improve efficiency in the dynamic wireless charging system for electric vehicles

2021-05-17T04:24:39+00:00

The transfer efficiency in a wireless power transfer system is maximized at optimum load impedance value. During the charging process, the load impedance value changes according to the state of charging of the battery which reduces transfer efficiency. This paper proposes a control method to improve efficiency in a dynamic wireless charging system for electric vehicles. Maximum transfer efficiency is achieved by controlling the load impedance according to the optimum load impedance value. However, in this systems, the optimum load impedance value depends on the position of the electric vehicle. Therefore, the paper also estimates the optimum load impedance value according to the position of the electric vehicle by the information measured on the secondary side. Furthermore, the secondary converter efficiency is also improved by used to the active rectifier. A 1.5kW dynamic wireless charging system is built in the laboratory to verify the feasibility of the proposed method. In the case of the receiver moving 30% misalignment, the transfer efficiency is increase by 6% compared with the case of fixed optimal load control. The system efficiency is achieved above 80%.

Space Vector Modulation with any number levels to ensure optimal switching and harmonic content in Modular multilevel converters

2021-06-23T07:48:22+00:00

This paper presents a Space Vector Modulation (SVM) method with an optimal switching process used for Modular Multilevel Converter (MMC) of any level. The proposed SVM method can produce a maximum number of levels, for example, 2N + 1, in which N is the number of Sub-Modules (SMs) per branch of the MMC. Compared with previous modulation methods, the proposed SVM modulation method can select the closest three vectors to generate the optimal transition states, making the computation more efficient. When applying this method to the MMC, it will create the advantage which it can be applied to any number of levels without looking up the transition state table: It can create many residual states for the purpose of balancing the capacitor voltage, optimize the switching process, and improve efficiency as well as harmonic quality of the AC voltage and current. The advantages of the method are well applicable to MMC when a large number of SMs is required to converse power in high voltage systems.

Output DC Voltage Stabilizer and Efficiency Improvement in Wireless Power Tranfer Systems

2021-05-21T02:30:19+00:00

In recent years, Wireless Power Transfer (WPT) technology has received remarkable attention because of its wide range of applications. To control the output voltage and maximize the efficiency of the system under variable conditions, primary-side phase shift H-bridge inverter and secondary-side semiactive rectifier are simultaneously utilized in this paper. The system with a two-sided LCC compensation network brings about a power of 2.5 kW, working frequency at 40 kHz and a transfer distance of 4.5 cm. Besides, the study suggests a formula to estimate the output power and calculate the tranfer power value needed to supply. This power controller uses phase-shift modulation method to help the system achieve maximum efficiency. To verify the theory above, the system is implemented on PSIM software and experimentally. A stable 400 V on the load is achieved with 2.3% control error, and the transfer efficiency is improved up to 90.9%.