Mercurochrome and N3 dyes are employed to be the sensitizers in ZnO-nanowire (NW) dye-sensitized solar cells (DSSCs). A lower fill factor is obtained N3-sensitized cell which results comparable efficiencies both ZnO-NW DSSCs although molecules possess a wider absorptive range for light harvesting. Electrochemical impedance spectroscopy open-circuit photovoltage decay measurements investigate electron transport properties DSSCs. The indicate that more abundant interfacial recombination occurs...

This paper proposes a permanent-magnet (PM) machine position-sensorless drive for high speed (> 10-kr/min) applications. A discrete-time back electromotive force (EMF) voltage estimation method is developed to overcome several high-speed position sensing issues, including the error due digital-to-analog conversion, inductive cross-coupling, and deviation between estimated EMF actual resulting from digital implementation. To these problems, an observer-based proposed with three implementation...

TiO(2) nanowire (NW)/nanoparticle (NP) composite films have been fabricated by hybridizing various ratios of hydrothermal anatase NWs and NPs for use in dye-sensitized solar cells (DSSCs). Scanning electron microscopy (SEM) images reveal that uniform NW/NP were formed on fluorine-doped tin oxide (FTO) substrates the dip-coating method. The are randomly but neither vertically nor horizontally oriented within film. NP DSSC possesses superior performance to those pure NW cells, efficiency...

Intensity-modulated photocurrent spectroscopy and intensity-modulated photovoltage are employed to measure the dynamics of electron transport recombination in ZnO nanowire (NW) array-ZnO/layered basic zinc acetate (LBZA) nanoparticle (NP) composite dye-sensitized solar cells (DSSCs). The roles vertical NWs insulating LBZA collection DSSCs investigated by comparing results those TiO(2)-NP, horizontal TiO(2)-NW ZnO-NW-array DSSCs. rate lifetime NW/NP DSSC superior conventional TiO(2)-NP cell...

Conventional permanent magnet (PM) machine open-phase fault detection relies on the estimation of current harmonics using available phase sensors. Because magnitudes harmonic are proportional to load condition, it is still a challenge detect at light when fault-induced too small estimate. This paper investigates specifically for conditions under low magnitudes. Both in dq currents and neutral point (NP) voltage analyzed find suited signal detection. By adding sensor measure NP PM machine,...

This paper improves the position sensorless drive by sensing actual machine phase voltages. A high-bandwidth voltage measurement is developed for pulsewidth modulation (PWM) inverters. On basis, obtained based on digital integration of PWM using capture modulator in existing microcontrollers (MCU's). Comparing to measurement, no separated A/D converter and communication hardware are required because pulses directly measured MCUs. However, standard machines without neutral points, only...

In conventional position sensorless permanent magnet (PM) machine drives, the rotor is obtained from phase-locked loop (PLL) with regulation of spatial signal in estimated back electromotive force (EMF) voltages. Due to sinusoidal distribution back-EMF voltages, a small-signal approximation assumed PLL order estimate position. That is, almost equal actual per sample instant. However, at high speed when ratio sampling frequency, fsample, over operating fe, low, this might not be valid during...

Conventional machine stator open-phase fault detection methods rely on the of current harmonics from sensing phase currents. Because magnitudes are proportional to load condition, it is a challenge for at light condition when fault-induced too small detect. This paper proposes an improved permanent magnet (PM) machines based use neutral point (NP) in Y-connected windings. It shown that first-order voltage harmonic resultant once occurs. Comparing with prior measurement, using NP insensitive...

This paper improves the surface permanent magnet (PM) machine position sensorless drive at low speed. Considering PM (SPM) drive, EMF voltage or flux linkage should be estimated for drive. Different from voltage, based on integration is theoretically independent to speed which suited estimation. In this paper, several improvements flux-based are proposed enhance dynamic performance. First, a modified develop remove estimation drift caused by current offset. contains high-pass filter (HPF) DC...

This paper investigates digital implementation issues on high-speed permanent magnet (PM) machine drives. The operating speed is designed beyond 30krpm where the ratio of controller sample frequency over rotor f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sample</sub> xmlns:xlink="http://www.w3.org/1999/xlink">e</sub> less than 5. Because microcontrollers are used in variable drives to realize field oriented control (FOC), discretized...

Voltage source inverter with pulse width modulation (PWM) usually has the switching frequency limitation at high frequency. It leads to degradation of speed machine drive as rotor f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">e</sub> increases. This paper is improve permanent magnet (PM) under insufficient PMW frequency, xmlns:xlink="http://www.w3.org/1999/xlink">pwm</sub> , over . In this paper, both trapezoidal brushless DC (BLDC) and...

This paper analyzes the influence of stator windings turn-to-turn fault on inverter-fed permanent magnet (PM) machines. By adding a secondary neutral point (NP) in windings, turn detection and tolerant capability can all improve considering small short at an early stage. From perspective detection, proposed with two NPs increase equipment impedance per NP. Once occurs, fault-induced voltage harmonic magnitude increases. It results better signal-to-noise ratio for detection. drive,...

Conventional permanent magnet (PM) machine open-phase fault detection relies on the estimation of current harmonics using existing drive sensors. Because magnitudes harmonic are proportional to load condition, it is still a challenge detect phase at light when induced too small estimate. This paper investigates specifically for conditions under low magnitudes. Both in dq currents and neutral point (NP) voltage analyzed find suited signal detection. By adding sensor measure NP PM machine,...

This paper addresses design issues on a position sensorless drive for permanent magnet (PM) synchronous machines in the entire speed range. At initial state, rotor magnetic polarity is identified based flux saturation through square-wave voltage injection. For low operation, spatial information saliency tracked closed-loop drive. The persistently injected to measure reflected current ripples estimation. high back-electromagnetic-force (EMF) estimated replacement achieve maximum under same DC...

Saliency-based position sensorless machine drive with the pulsewidth modulation (PWM) voltage switching frequency injection has advantages of high estimation bandwidth and low acoustic noise. However, multiple currents must be sampled every PWM cycle for spatial saliency calculation. Besides, distorts symmetric pattern. For these saliency-based drives, is tradeoff between transient steady state error. This article proposes a modified through measurement vector insertion (MVI) estimation. By...

For pulse width modulation (PWM) inverter drives, an LC filter can cascade to a permanent magnet (PM) machine at output reduce PWM-reflected current harmonics. Because the causes resonance, and voltage are required for sensorless field-oriented control (FOC) drive. However, existing sensors inverters typically integrated inside commercial closed-form drives; it is not possible these drives obtain additional signals. To resolve this integration issue, paper proposes state estimation using...

Saliency-based position sensorless drive with the pulse width modulation (PWM) switching frequency injection can achieve high estimation bandwidth. However, in order to obtain rotor position, multiple currents should be sampled every PWM cycle calculate saliency reflected current difference. Considering low-cost inverter using shunt resistors for phase sensing, it is not possible this difference because machine only measured once low-side switch ON. To implement on shunt-based sensing...

This paper improves the permanent magnet (PM) machine position sensorless drive specifically for high speed operation. To obtain rotor position, an approximation is typically assumed on estimator where estimated almost equal to actual per sample instant. small signal might not be valid at when ratio of sampling frequency over operating lower than 10. In this paper, limitation EMF-based analyzed. By modifying without approximation, it shown that can improve operate 30-krpm with only five...

This paper analyzes the stator windings turn-to-turn fault tolerant capability on inverter-fed permanent magnet (PM) machines. By adding a secondary neutral point (NP) in windings, both detection and can be improved considering small short at early stage. From perspective of detection, proposed two NP's increase equipment impedance per NP. Once turn occurs, induced voltage harmonic magnitude increased. It results better signal-to-noise ratio for detection. drive, circulating currents flow...

This paper improves the position sensorless drive by directly measuring machine three-phase voltages. On basis, phase voltage is obtained based on digital integration of pulse width modulation (PWM) voltage. The capture modulator in existing microcontrollers (MCU's) used for PWM measurement. Comparing to measurement, no separated A/D converter and communication hardware are required because pulses measured using MCUs. However since TTL logics receives only signals, a preprocess circuit...

This paper analyzes current sampling issues on the saliency-based position sensorless drive for permanent magnet (PM) machines using pulse width modulation (PWM) voltage injection. On basis, PWM with switching frequency is persistently injected into machine. The rotor estimated through spatial signal from reflected ripples. Because every cycle, multiple transient currents instead of single average should be sampled per PWM. It leads to issue selection points respect different patterns. In...

This paper improves a flux-based position sensorless drive for surface permanent magnet (PM) machines. On the basis, rotor is obtained from spatial information in flux. The flux estimation realized based on integration of EMF voltage. In this paper, several implementation issues are considered to improve drive. First, machine phase voltage measured estimation. By obtaining actual inverter outputs, deaditme effect negligible and Second, modified proposed remove drift due offset. Because...

This paper proposes a permanent magnet (PM) machine position sensorless drive for high speed (>10-krpm) applications. A fully discretized back electromotive force (EMF) estimator is designed to overcome several rotor estimation issues, including the voltage error due pulse-width-modulation (PWM), dq inductance cross-coupling effect and deviation between estimated EMF actual resulting from digital implementation. To these problems, an observer-based proposed with two implementation...

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