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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. Index Terms--Application-specific integrated circuits (ASICs), digital control, field-programmable gate arrays (FPGAs), hardware description languages (HDLs), motor drives.

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. Index Terms--Active power filter, harmonic and reactive power compensation, nonideal mains voltage, power quality.

In this study, a new multi-point clamped (MPC), three-phase two-leg, five-level unidirectional front end high-powerfactor converter is proposed for directly connected wind energy conversion system with a permanent magnet synchronous generator. The proposed topology can be modelled and modulated similarly to other existing MPC structured converters with the omission of clamping diodes and bidirectional switches. The proposed converter has an advantage of reduced power semiconductor device count and maximum device stress. A factor (normalised index) is introduced and comprehensive comparative analysis with N level existing topologies is carried out. The minimum value of the normalised index makes the proposed topology as a suitable option for medium-voltage and high-power applications. Also, the fault ride through capability is one of the key performance indicators is also investigated on proposed topology under voltage sag condition. Further, steady state and transient performance of topology during load as well as dc-link voltage change are presented. Minimum distorted and balanced line currents with unity power factor are drawn from supply by implementing negative sequence elimination control algorithm. The validation of proposed topology is verified with simulation and a down-scaled experimental setup. [ABSTRACT FROM AUTHOR]

In this study, a modulation strategy is presented using minimum number of switching transitions of optimised switching sequences for balancing of DC-bus capacitor voltages of a three-phase neutral-point clamped bi-directional converter. This new approach is derived from the fact that in front end AC-DC converters, the location of supply voltage vector and reference current vector (magnitude and lag angle) vary depending upon the amount of reactive power compensation and the load current to be supplied by converter. Accordingly, the effect of small and medium vectors (using space vector pulse-width modulation) for same switching state varies in each sector and its regions resulting in DC-bus capacitor voltage unbalancing. This observation along with the detailed analysis of current pattern for both the capacitors within each sector and its regions and its effect on neutral-point voltage deviation forms the basis of proposed approach of maintaining optimised space vector sequences and changing the number of sampling periods within each sector and its regions, thus resulting in DC-bus capacitor voltage balancing. As a result, modified reference current vector spends different amount of time in alternate sectors (moves faster and slower in alternate sectors) but total time for one complete cycle is same as actual current vector. The converter exhibits excellent performance in terms of other critical parameters like unity input power factor, low input current THD, minimum switching losses, reduced ripple factor of the regulated DC output voltage and particularly, the neutral-point voltage deviation under dynamic load conditions both for rectification and inversion modes of operation. [ABSTRACT FROM AUTHOR]

Many proteinuric renal conditions are accompanied by renal inflammation. Nicotine is known to have anti-inflammatory properties and is used in oral form to help subjects quit smoking. A potential anti-inflammatory role of nicotine in proteinuric renal diseases has not been investigated to date. We therefore evaluated the effects of oral nicotine in a rat model of proteinuria-induced renal inflammation. We used a well-established model of adult (24 wk of age) male Munich-Wistar-Frömter rats. Animals were given three different physiological doses of nicotine in drinking water for 28 wk until 52 wk of age (long term). A group without nicotine served as a parallel control. At 52 wk of age, the control group had a 2.1 times reduction in creatinine clearance, 3.2 times increase in urinary protein excretion, an increased focal glomerulosclerosis (FGS) score, increased glomerular desmin deposition, decreased glomerular podocin, and a higher accumulation of macrophages and myofibroblasts compared with 24-wk-old animals. Oral treatment with nicotine dose dependently preserved renal function and halted proteinuria progression, which were independent of blood pressure reduction. It also reduced FGS, desmin deposition, podocin loss, and density of renal macrophages and myofibroblasts. Nicotine also reduced the level of gene expression of the renal inflammatory markers monocyte chemoattractant protein and vascular cell adhesion molecule-1. In conclusion, long-term oral nicotine preserved kidney function, reduced proteinuria, reduced renal inflammation, and protected progression of renal structural damage in a rat model of proteinuria. We further suggest evaluating nicotine as a potential additional therapeutic option for treating proteinuric kidney diseases. [ABSTRACT FROM AUTHOR]

This paper investigates the importance of controllers on energy saving opportunity of partial loaded three-phase induction motor in mine hoist applications. The input power of a vector controlled 1 HP induction motor is investigated with three topologies namely constant flux operation, loss model based flux controller using Particle Swarm Optimization (PSO) and search controller in steady-state conditions. In this study, the flux level in a machine has been considered to adjust to give minimum input power for a given load of the motor. Even though flux controllers improve the performance of the motor in terms of minimum input power, they offer ripples in torque and speed of the motor (lower stability). To increase the stability of the motor drive during variable speed and load operation, Fuzzy Pre-compensated Proportional Integral (FPPI) Controller is used and compared its results with conventional Proportional Integral (PI) controller. According to the test results DE along with fuzzy logic outperforms the conventional controllers and saves 100 W power in the test motor. Four benchmark problems are used to validate PSO algorithm. C++ code is used for PSO implementation. [ABSTRACT FROM AUTHOR]

This paper illustrates the importance of controllers on energy saving opportunity of partial loaded three-phase induction motor in textile mill (ring spinning frame) applications. The economics of a scalar controlled 100 HP induction motor is investigated with three topologies namely star-delta (S/D) connection, constant Volt/frequency (V/f) controller and Differential Evolution (DE) controller in steady-state conditions. In this study, the flux level in a machine has been considered to adjust to give minimum operating cost for the textile mill load. The flux controller improves the economics in terms of operating cost (energy cost and demand charge cost) and the test results show that the flux level in the most economic motor will be adjusted according to load and speed, particularly at light load. Standard benchmark problems (Rastingin and Griewank) have been considered for validation of the proposed DE controller for induction motor operating cost minimization. Case study also presented in this paper. [ABSTRACT FROM AUTHOR]

This paper presents an optimal design and its realization of poly-phase induction motor using Quadratic Interpolation based Particle Swarm Optimization (QI-PSO). The optimization algorithm considers the efficiency, starting torque and temperature rise as objective function (which are considered separately) and nine performance related items as constraints. The QI-PSO algorithm was implemented on a test motor and the results are compared with the Simulated Annealing (SA) technique, Standard Particle Swarm Optimization (SPSO), and normal design. Some benchmark problems are used for validating QI-PSO. From the test results QI-PSO gave better results and more suitable to motor's design optimization. Optimized variables are realized by PC-IMD (Induction Motor Drives) of SPEED (Scottish Power Electronics and Electric Drives) software. C++ code is used for implementing entire algorithms. [ABSTRACT FROM AUTHOR]