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The aim of this paper is to study the dynamics of a permanent magnet direct current (PMDC) brushed motor while two crucial space-domain effects, namely, slotting effect and commutation phenomenon are taken into account. Semi-analytical dynamic time-domain PMDC brushed motor model inclusive of these space-domain effects is used to analyze and investigate the dynamics. Pulse width modulation operated discontinuous current PMDC brushed motor drive with steady duty cycle is employed to acquire the bifurcation patterns. The chaotic nature due to slotting effect and commutation is identified from the bifurcation patterns and reported. It also has to be admired that such nonlinear dynamical behavior with the same set of parameters at similar operating condition has not been observed when a conventional PMDC brushed motor dynamic model is considered. These space-domain effects, namely, slotting effect and commutation also have a prominent impact to make some time-domain states of a PMDC brushed motor drive chaotic. The role of slotting effect and commutation phenomenon to analyze the chaos over time-domain state variables of the PMDC brushed motor drive is investigated and validated experimentally in this paper. [ABSTRACT FROM PUBLISHER]

In order to ensure zero steady-state error in multi-area hybrid power systems, load frequency control is implemented in the power system. However, variations in load due to cyclic amplitude deviation create frequency fault leading to unscheduled tie-line power. Hence a novelOperational Load Forecasting Approach is utilized in which objective function in support vector regression predicts load demand and generation based on temporalcharacteristicsand utilize parallel processing to tolerate the acceptable error margin. Moreover, the uncertainties of active power generation in islanding mode make the estimation of frequency response deviation under decentralized islanding modes difficult. Hence a novelDifferential ControllerAlgorithm has been proposed in which the sigmoidal range function determines the optimal amplitude value from individual areasand the controller predicts the high load demand area that exceeds the threshold limit and isolatesthat area until the deviation is rectified. Low tie-line power, frequency, and settling time deviations were accomplished using the proposed methodologies as they were simulated using the Simulink platform. [ABSTRACT FROM AUTHOR]

Thermal comfort standards are required to provide comfortable indoor condition which has a positive effect on the occupant. However, the Predicted Mean Vote – Percentage People Dissatisfied (PMV-PPD) model which is used to determine the indoor comfort in most of the international standards fails often, especially in naturally ventilated buildings. Several field studies were conducted elsewhere to determine the comfort condition, but very few are reported for the cold and cloudy type of climate and in hilly region. In this paper, the results of field studies conducted in 10 buildings of different types located in varying elevation are presented. A total of 2608 responses of thermal comfort were collected from 436 subjects between January and December 2015. The mean clothing insulation of the subjects were found to increase with the increase in the elevation of the location and this difference was statistically significant, t  = −94.05 (df = 2607, p  < 0.001). The yearly mean clothing insulation in S0135 was 0.640 clo, K1420 was 0.722 clo, M1640 was 0.947 clo, S1950 was 1.055 clo and T2565 was 0.907 clo, respectively. Whereas, the mean comfort temperature decreased with the elevation of the location and this difference was also statistically significant, t  = −92.34 (df = 2607, p  < 0.001). The yearly mean comfort temperature for the location S0135 was 28.37   °C, K1420 was 20.59   °C, M 1640 was 20.07   °C, S1950 was 19.72   °C and T2565 was 17.35   °C, respectively, where the digits in the locations (i.e. 0135 in S0135, 1420 in K1420, 1640 in M1640, 1950 in S1950 and 2565 in T2565) represents the elevation of the location under study in meters above mean sea level. A relation of the indoor comfort temperature with the outdoor environmental conditions and with the elevation of the location under study is obtained. [ABSTRACT FROM AUTHOR]

This paper proposes a novel fuzzified mechanical sensorless speed estimation technique for permanent magnet direct current (PMDC) brushed motor operated with pulse width modulation (PWM) based terminal voltage. For replacement of conventional mechanical speed sensors, few mechanical sensorless speed estimation techniques have been reported recently in the field of PMDC brushed motor. In this paper, a novel technique is applied over a recently reported semianalytical dynamic time-domain PMDC brushed motor model incorporating space-domain effects, namely slotting effect and commutation phenomenon to simulate the proposed estimation process. Ripple and back electromotive force based standalone estimation approaches are hybridized in order to eliminate uncertainties in all regions of estimation. In this paper, a discrete fuzzified hybrid speed estimation model has been proposed with adequate dynamic simulation responses. Further the proposed discrete speed estimation model has been applied experimentally over a PWM-driven 24-V, 12-teeth, 100-W PMDC brushed motor and various dynamic real-time responses have been compared with conventionally captured speed samples to validate the proposed model. [ABSTRACT FROM PUBLISHER]

• Wide range dimmable LED driver. • Achieves deep dimming maintaining low flicker metrics as recommended in IEEE Std. 1789-2015 to avoid health risks associated with flickering of LED. • Achieves dimming with interleaved operation of buck converter where variable frequency constant 50% duty ratio PWM signal is fed to the converter. • The usage of electrolytic capacitor (limits the lifespan of LED driver) is avoided in the driver circuit. In the field of dimming of high brightness LED, variable duty ratio pulse-width-modulation (PWM) operated LED dimmable drivers are commonly used which cause high flicker metrics resulting visual discomfort and health risks of the viewer as pointed in recently reported IEEE Std. 1789-2015. In IEEE Std. 1789-2015, a low flicker metrics such as flicker index and modulation depth are recommended to avoid those health hazards. Such flicker metrics are to be calculated from modulating LED current and have to be sufficiently low and also modulation depth should lie within a prescribed operating region as recommended in IEEE Std. 1789-2015. In this paper a variable-frequency constant duty ratio PWM operated novel driving scheme has been proposed for DC-DC wide range dimmable LED driver which performs dimming with a low flicker metrics. The reported driving scheme does not require any electrolytic capacitor in the driver unit and hence low life span of electrolytic capacitor does not deteriorate life span of LED driver unit. Both simulation and experimentation have been carried out and reported in this paper with adequate responses. Also comparative analyses of flicker metrics of the proposed driving scheme with existing conventional PWM operated dimmable LED drivers have been reported. [ABSTRACT FROM AUTHOR]