A Practical Comparative Evaluation of Different Active Harmonic Filter Topologies

Along the last years, the practical use of active filters to mitigate harmonics has been extended in electric power systems. Different configurations of series active filters versus shunt active filters have been proposed, among them, hybrid topologies which combine active and passive filters. Nevertheless, there is not any clear accordance about the most suitable configuration for each type of harmonic sources. In this paper, four different topologies of active power filters to eliminate harmonics have been analyzed. An experimental prototype has been implemented to each configuration and have been submitted to different performance tests. With this objective, a test bank has been developed, which includes nonlinear loads kind harmonic current source, ahrmonic voltage source, and other whose behavior is between they both. The analysis of experimental results obtained allows the most suitable active filter power topology to be determined for each type of load

Electrical complex of combined power supply on the base of renewables and hybrid correction device

The main topic of presented article is the effective application of alternative and renewable energy sources with demanded level of power quality and electromagnetic compatibility. This decision is especially actual in conditions of industrial enterprises with continuous mode of technological process and responsible consumers. The configuration of electrical complex of combined power supply on the base of renewables and hybrid correction device is developed and proved in this article. Also the control algorithm of proposed electrical complex functioning is developed. The main functions of hybrid correction device, which is included in proposed electrical complex structure, are determined. The mathematical model of proposed electrical complex is developed. The results of mathematical modeling and computer simulation show the satisfactory level of power quality and electromagnetic compatibility in conditions of application of developed electrical complex

Engineering Subsystems Analysis of Adaptive Small Satellites

The current point-based satellite electronic subsystem engineering design process is insufficient to address the dynamic operations and post-mission reuse of small satellites. Also, space systems and missions require an adaptive architecture(s) that can withstand the radiation-prone flight environment and respond to in-situ environmental changes using onboard resources while maintaining optimal performance. This enormous conceptual design variables space/task of highly adaptive small satellite (HASS) system can be too large to explore, study, analyse and qualify. This research involved a parametric electronic subsystem engineering design process and methodology development for the production of sustainable capability-based small satellites. Consequently, an adaptive multifunctional architecture with five levels of in-orbit spacecraft customisations that eliminate subsystem boundaries at the system level is presented. Additive manufacturing methods are favoured to fabricate the proposed adaptive multifunctional monolithic structures. The initial system engineering analyses reveal that the HASS system has mass-, cost- and power-savings over the conventional small satellite implementation. An adaptive small satellite link performance improvement satisfying a less than 2 dB link margin loss for a 0.1 dB in-band noise figure ripple has been established. Moreover, a power budget model for HASSs that ensures a reliable solar array design and eliminates undue equipment oversizing has been developed. An adaptive broadband beamformer that can improve the satellite link margin has been designed. Also, an estimating relationship has been developed and practically validated for the operational times analysis of small satellite subsystems. The reported novel findings promise to enable capability-based, adaptive, cost-effective, reliable, multifunctional, broadband and optimal-performing space systems with recourse to post-mission re-applications

FPGA Based Active Power Filter for Harmonics Mitigation

The application of power electronics devices such as arc furnaces, adjustable speed drives, computer power supplies etc. are some typical non-linear characteristic loads used in most of the industrial applications and are increasing rapidly due to technical improvements of semiconductor devices, digital controller and flexibility in controlling the power usage. The use of the above power electronic devices in power distribution system gives rise to harmonics and reactive power disturbances. The harmonics and reactive power cause a number of undesirable effects like heating, equipment damage and Electromagnetic Interference effects in the power system. The conventional method to mitigate the harmonics and reactive power compensation is by using passive LC filters but this method has drawbacks like large size, resonance problem and fixed compensation behaviour etc., so this solution becomes ineffective [7]. Subsequently, the active power filter (APF) comes in to the picture, which gives promising solution to compensate for the above adverse effects of harmonics and reactive power simultaneously by using suitable control algorithms. Different APF topology has proposed by many authors, such as series, shunt and hybrid type and these may be based on current source or voltage source. Series APF is used to compensate the voltage harmonics and shunt type for current harmonics. As non-linear loads are injecting current harmonics to the power system, the suitable choice to eliminate current harmonics and reactive power is voltage source shunt APF. To extract the fundamental component of source current synchronous reference frame (SRF) theory [12] is suitable because of its easy mathematical calculation compared to p-q (Instantaneous theory) control algorithm. Further, switching signals to drive the VSI of the APF two popular control strategies namely hysteresis current controller (HCC) and adaptive hysteresis current controller (Adaptive- HCC) are used. Also fuzzy logic controller is used generate the reference current and maintain the DC side capacitor voltage almost constant. A comparative study of the performances of two current control strategies HCC and Adaptive-HCC is carried out in this thesis and it has been observed from simulation results that AHCC exhibits superior performance compared to the HCC. These current controllers have some disadvantages such as high cost, slow response, and large size etc., during real-time implementation. But by using digital controller one can avail the advantages like reconfigurable hardware designs, low cost developments, selection of bit width according to applications etc. In this thesis, a PI current control algorithm together with a hysteresis current controller is written in VHDL code and then is implemented using FPGA platform

Study and RTDS implementation of some controllers for performance and power quality improvement of an induction motor drive system

The present research work is directed to study of some controllers for design, modelling, simulation and RTDS implementation of induction motor (IM) drive system to identify suitable controller for high performance.Initially dynamic modelling and simulation of a feedback linearization scheme for high performance IM drive is carried out. The flux measurement required in this scheme is achieved using flux estimator rather sensor to simplify the system. The complexity and calculation involved in reference frame transformation is taken care by implementing the scheme in stationary reference frame. Two linear and independent subsystems: (i) Electrical and (ii) Mechanical are created by linearizing control scheme. The systematic design of closed loop control scheme using Proportional Integral (PI) controller is developed for implementation. To take care of uncertainties in the system the Fuzzy controller is added to speed controller. Sliding Mode (SM) controller considered to be a robust control strategy is designed and developed for IM drive. A procedure of finding gain and bandwidth of the controller is developed to take care of model inaccuracies, load disturbances and rotor resistance variation. During practical implementation of this controller for IM leads to oscillations and of state variable chattering due to presence of limiter and PWM inverter in the system. Iterative Learning controller (ILC) introduced in recent time is gaining popularity due to capability to take care of short comings of Sliding Mode controller. Feedback and feed forward Iterative Learning controller combining fuzzy logic is designed and developed. The MATLAB/SIMULINK model of IM drive with controllers designed are simulated under various possible operating conditions. A comparative study of three controllers is carried out in similar situation and the response of the drive system is presented.Normally we neglect stability aspect of IM while investigating procedure for performance improvement of IM drive. Stability study of IM in open loop and closed vii loop conditions using Lyapunov criteria and also considering the power balance equation are presented

Design and Implementation of Shunt Active Power Line Conditioner using Novel Control Strategies

Shunt Active Power Filter (APF) or Active Power Line Conditioner (APLC) is designed and implemented for power quality improvements in terms of current harmonics and reactive-power compensation. The widespread use of non-linear loads in industrial, commercial and domestic facilities cause harmonic problems. Harmonics induce malfunctions in sensitive equipment, overvoltage by resonance, increase heat in the conductors, harmonic voltage drop across the network impedance and affects other customer loads connected at the Point of Common Coupling (PCC). Active power line conditioner is implemented for compensating the harmonics and reactive-power imultaneously in the distribution system. The performance of the active power line conditioner depends on the design and characteristics of the controller adopted for APLC. The objective of this research is to find a suitable control strategy for reference current extraction as well as PWM-VSI current controller. PI / PID / FLC / PI-FLC, Fryze power theory, proposed instantaneous realpower theory, proposed sinusoidal extraction controller and modified-synchronous reference frame theory methods are utilized for extracting reference current.Furthermore, indirect PWM-current control (triangular-carrier / triangular-periodical current controller, space vector modulation controller, fixed-Hysteresis Current Controller (HCC), adaptive-HCC and adaptive-fuzzy-HCC) approach is applied to generate switching pulses of the PWM-inverter. Each reference current extraction method in conjunction with various PWM-current control techniques (or vice-versa) are simulated and investigated for the active power line conditioner. For experimental validation, the modified-synchronous reference frame with adaptive-fuzzy-HCC technique is adopted. This control algorithm is demonstrated through the TMS320F240 Digital Signal Processor for shunt APLC system