October'22
Focus
The Quadrature Sinusoidal Oscillators (QSOs) are widely used in telecommunications and are realized using different active building blocks. In the second paper, "New Third-Order Quadrature Sinusoidal Oscillator Employing Current Differencing Buffered Amplifiers" by Komal, Ramnish Kumar and K L Pushkar, Third-Order Quadrature Sinusoidal Oscillator (TOQSO) using current differencing buffered amplifiers is proposed. TOQSO circuit design is based on a combination of non-inverting/inverting second-order low pass filter and inverting/non-inverting lossless integrator in a feedback loop. The performance of the proposed circuit has been verified in PSPICE simulator and found to be superior to the other designs proposed in the literature.
In the third paper, "DVA Design for Wide Area Damping Control of Power System" by Digvijay Nair, design of a fault-tolerant Wide Area Controller (WAC) to dampen the oscillations in a power system is described. The controller includes a reconfigurable component called Dynamic Virtual Actuator (DVA). The performance of the proposed controller is demonstrated using a two-area power system model.
Low Voltage Ride Through (LVRT) techniques are employed to prevent solar PV systems getting isolated from the grid when faults occur. In the fourth paper, "Performance Analysis of Three-Phase Grid-Connected Solar Photovoltaic System with Dynamic Grid Support System" by Sagar N Vegad and J R Iyer, a synchronous reference frame-based current control technique for solar PV inverters with Low Voltage Ride-Through (LVRT) control is proposed. The control design has been verified by simulating on a typical grid connected 400 kW solar PV plant using MATLAB.
In the last paper, "Speed Control of PMSM for Wind Turbine Application: A Comparative Evaluation of FOC and DTC Strategies" by Sumit Dave, Mihir Vasavada, Shivani S N and Bhatt K A, various control strategies for Permanent Magnet Synchronous Motor (PMSM) drives like Field-Oriented Control (FOC) and Direct Torque Control (DTC) are reviewed.
Ensemble Weighting Strategy for Federated Learning to Handle Heterogeneous Data Distributions
Measured data in the context of smart cities can be used to develop new and innovative business models to improve efficiency and the value of life. A time-series classification algorithm can help automatize many different processes such as forecasting services. In order to ensure data security and privacy, Federated Learning trains a global model collaboratively on multiple clients. Having different data-distributions and data-quantities across participating clients, neural networks suffer from slow convergence and overfitting. Based on different data values and number of clients, different data-clustering strategies have been developed and evaluated in this study to update global model weights. Public time-series data has been downloaded from the Internet to generate various synthetic datasets and train a Relational-Regularized Autoencoder for classification purposes. The results showed an improvement of model performance concerning generalization.
New Third-Order Quadrature Sinusoidal Oscillator Employing Current Differencing Buffered Amplifiers
The paper presents a Voltage Mode (VM) Third-Order Quadrature Sinusoidal Oscillator (TOQSO) using Current Differencing Buffered Amplifiers (CDBA). The proposed TOQSO is designed using two CDBAs, four resistors and three Grounded Capacitors (GCs). The circuit is suitable for integrated circuit realization as all the capacitors are grounded. The Condition of Oscillation (CO) and Frequency of Oscillation (FO) of the presented circuit are self-regulating, i.e., CO can be regulated by resistor and capacitor, and the FO can be tuned. Non-ideal analysis is carried out, and the results are compared with ideal ones. Sensitivities of FO with respect to active and passive components are evaluated and found to be less and low Total Harmonic Distortion (THD). The presented configuration has power dissipation 1.01 mW at ±0.9 V supply voltages. The feasibility of the presented circuit is validated using CMOS CDBA with supply voltage ±0.9 V.
DVA Design for Wide Area Damping Control of Power System
The paper proposes a novel approach to fault tolerant control design of wide area damping controller for the power system. The design of a reconfigurable component called Dynamic Virtual Actuator (DVA) for effective and reliable wide area damping control action is presented. The design features of DVA include: (i) optimum control action during both nominal system condition and actuator faults; (ii) online calculation of the parameters of DVA in real-time on actuator faults; (iii) dynamic parameters of DVA that are function of the actuator faults; and (iv) it allows to continue to use controller, designed for nominal system condition even on actuator faults. The effectiveness of the design of DVA in damping of low frequency oscillations in power system is demonstrated. Kundur two-area power system model is considered for the design implementation of DVA. The results show successful damping of the oscillations on simulation of actuator faults in wide area control of the power system.
Performance Analysis of Three-Phase Grid-Connected Solar Photovoltaic System with Dynamic Grid Support System
Global energy needs are growing continuously, and there is now more focus on renewable energy sources. Solar Photovoltaic (PV) and wind have the major contribution among utility-level renewable energy sources. In India, till now grid-connected solar PV systems do not follow any specialized controls for grid support during disturbance and they isolate the solar PV system immediately with the help of anti-islanding technique. The paper presents a synchronous reference frame-based current control technique for solar PV inverters with low voltage ride-through control. A detailed performance analysis of grid-connected solar PV systems with and without low voltage ride-through control for various types of grid faults has been carried out. Various parameters like active and reactive power injection, circuit breaker opening time, dc-link voltage magnitude and voltage magnitude at the Point of Common Coupling (PCC) are recorded for symmetrical and unsymmetrical faults.
Speed Control of PMSM for Wind Turbine Application: A Comparative Evaluation of FOC and DTC Strategies
The paper reviews and compares the most popular control strategies for Permanent Magnet Synchronous Motor (PMSM) drives, viz., Field-Oriented Control (FOC) and Direct Torque Control (DTC). The comparison is based on various criteria, including basic control characteristics, dynamic performance, and implementation complexity. The choice of an exact Maximum Power Point Tracking (MPPT) algorithm for a particular case requires sufficient proficiency because each algorithm has its own advantages and disadvantages. Hence, an appropriate review of these algorithms is essential. The simulation and evaluation of various control strategies are reviewed using actual parameters of PMSM used for wind turbine and a new strategy for real-time speed control of PMSM in a motoring mode for variable speed wind energy conversion system application is proposed with better dynamic response characteristics.
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