Pramod Agarwal

Design Simulation and Experimental Investigations, on a Shunt Active Power Filter for Harmonics, and Reactive Power Compensation

This paper presents complete design, simulation, and experimental investigations on a 3-phase shunt active power filter to compensate harmonics and the reactive power requirement of nonlinear loads. The paper describes the complete design aspects of power circuit elements and control circuit parameters. The compensation process is based on sensing line currents only, an approach different from conventional methods that require the harmonics and reactive volt-ampere requirement of the load. Various simulation results are presented to study the performance during steady-state and transient conditions to validate the design. A laboratory prototype has been developed to verify the simulation results. The control scheme is realized on a dedicated micro-controller-based system. PWM pattern generation is based on carrierless hysteresis-based current control to obtain the switching signals. Based on simulation and experimental results it can be concluded that the compensation process is simple and easy to implement. The spectral performance shows that the active filter brings the THD of the system well below 5%, the limit imposed by the IEEE-519 standard.

Energy Efficient Control of Three-Phase Induction Motor - A Review

Due to robustness, reliability, low price and maintenance free, induction motors (IMs) used in most of the industrial applications. The influence of these motors (in terms of energy consumption) in energy intensive industries is significant in total input cost. This paper presents a review of the developments in the field of efficiency optimization of three-phase induction motor through optimal control and design techniques. Optimal control covers both the broad approaches namely, loss model control (LMC) and search control (SC). Optimal design covers the design modifications of materials and construction in order to optimize efficiency of the motor. The use of Artificial Intelligence (AI) techniques such as artificial neural network (ANN), fuzzy logic, expert systems and nature inspired algorithms (NIA), Genetic algorithm and differential evolution in optimization are also included in this paper. Experimental and simulation examples on efficiency optimization are illustrated.

A control algorithm for compensation of customer-generated harmonics and reactive power

This paper presents a new control algorithm for a shunt active power filter to compensate harmonics and reactive power required by nonlinear loads. If the utility voltage is distorted, active power filter (APF) allows similar level of distortion in the compensated source current. Therefore, the resultant source currents have the same waveform as that of the supply voltage, thereby attributing the responsibility of utility and customer at the point of common coupling (PCC). Due to similar shape of the source voltage and currents, reactive power is compensated completely. The proposed scheme provides an additional feature of compensation of either only harmonics, or both harmonics and reactive power simultaneously, based on the desired capacity of the APF. Various simulation results are presented with ideal and distorted mains voltage and compared with other algorithms. Proposed algorithm is implemented as a prototype to verify the simulation results.

Programmable Logic Devices for Motion Control—A Review

Programmable logic devices (PLDs) are increasing their presence in power electronics and motion control applications. With rising gate densities of PLDs, larger functionality is being incorporated. This paper looks at certain areas of motion control that are making use of PLD for faster control and in taking the processing load off the system microprocessor

Carrier-Based Neutral Point Potential Regulator With Reduced Switching Losses for Three-Level Diode-Clamped Inverter

This paper presents the design and implementation of a simple neutral point potential (NPP) regulator for a three-level diode-clamped inverter employing a sine-triangle regulator in conjunction with a closed-loop controller with reduced switching losses. The regulator principle is based on adding a continuous variable offset voltage which regulates the midpoint potential of the dc bus. The novelty of the proposed NPP regulator is in the determination of the magnitude of variable offset voltage based upon the average value, peak-to-peak amplitude, total harmonic distortions, and third harmonic content in NPP. Aside from maintaining dc-bus voltage balance, the proposed regulator leads to a significant reduction in the voltage distortion at the NP, resulting in the reduction of the required dc-bus capacitance. It also reduces the switching losses of the inverter by inserting the “no-switching” zone within each half cycle of the fundamental voltage wave. Analytical, computer simulation, and experimental results verifying the approach are presented in this paper for various load power factor angles.

Auto-tuned, discrete PID controller for DC-DC converter for fast transient response

Ziegler-Nichols tuned PID controllers performances usually are not acceptable for applications requiring precise control. In this paper an improved discrete auto-tuning PID scheme is developed for DC-DC converters where large load changes are expected or the need for fast response time. The algorithm developed in this paper is used for the tuning discrete PID controller to obtain its parameters with a minimum computing complexity and is applied to Synchronous buck converter to improve its performance. To improve the transient response and rise time of the Converter, the controller parameters are continuously modified based on the current process trend. For its implementation a synchronous buck converter is designed and its MATLAB/Simulink model with non-linear parameters is developed and considered. Also, the non-linear effects such as S/H, quantization, delay, and saturation are considered in the close loop model. The simulation results demonstrate the effectiveness of the developed algorithms.

Implementation of Cascade Multilevel Inverter-based STATCOM

Abstract This paper deals with the real time implementation of 11-level cascade multilevel inverter-based STATCOM using personal computer (PC) and ADD-ON cards for power system voltage control at the point of common coupling. Complete hardware and software development procedures have been explained in depth for direct as well as indirect control schemes. Experimental results are presented and it is shown that voltage control is achieved using cascade multilevel inverter based STATCOM, thus verifying the very basic purpose of STATCOM. Real time implementation using PC-based control technique has certain merits over digital signal processor based implementation, and some of these merits are high processing speed and low cost of implementation; therefore, PC-based implementation can be used in industry as well as for utility applications.

Optimal energy control of induction motor by hybridization of loss model controller based on Particle Swarm Optimization and search controller

This paper presents simulation studies on the optimal energy control of an inverter-fed three-phase induction motor (1 hp). An overview of various controllers: loss model controller, search controller and their hybridization are given. Induction motor parameter variations due to temperature rise and core saturation are considered when loss models are derived. Mine hoist drive of a mineral industry and the implementation of efficiency optimization controllers with the help of Particle Swarm Optimization (PSO) and fuzzy logic are given. Fuzzy Pre-Compensated Proportional Integral (FPPI) is used to improve motors dynamic performances during the activation of optimal energy control. Analysis shows that it is possible to conserve energy in Indian industries by choosing several possible ways of implementing optimal energy control.

An Improved Performance Three-Phase Neutral-Point Clamped Rectifier with Simplified Control Scheme

In this paper, an improved performance 3-phase, neutral-point clamped bidirectional rectifier with simplified control scheme is proposed. A complete mathematical model of the rectifier using PWM controller is developed. A comparative analysis of two-level and three-level converter is done and the performance of both types of converters is evaluated in terms of the input power factor, input current THD, and ripple factor of the regulated dc output voltage. The merits and demerits of both types of converters are discussed. It is shown that the multi-level ac to dc converter with proposed control scheme is superior to its two-level counterpart and gives better performance like unity input power factor, negligible input current THD, and reduced-rippled regulated dc load voltage at a lower switching frequency and reduced voltage stress of the power semiconducting devices. The neutral point potential balance is also achieved with the proposed control technique

Use of multilevel inverter for elimination of harmonics in high voltage systems

In this paper five level multilevel inverter based shunt active power filter is presented. Active power filters (APF) are effective to reduce harmonics due to non-linear loads in low voltage system. But its use in high and medium voltage system is limited due to semiconductor rating constraints. In high voltage system high rating transformer is required with APF which causes high cost and bulky system. But application of multilevel inverter in active filters effectively reduces harmonics in high voltage system without use of transformer. The signal reference is generated by using p-q theory considering loss component of APF by comparing dc capacitor voltages with reference dc voltage. Carrier phase shifted pulse width modulation scheme is implemented to generate switching signals. Simulated results prove the effective elimination of harmonics with multilevel inverter in high power system.