Low-cost photovoltaic emulator for instructional laboratories

This paper discusses a simple and cheap PV emulator based on a linear power supply that does not require a source of light to conduct laboratory experiments. The emulator has been designed to underpin students' understanding the properties of PV cell V-I characteristics and the ways to maximise the output power learned from lectures, tutorial and self-studies. The emulator has been built using “on the shelf” components and tested under rated power conditions. It demonstrated a good emulation of V-I characteristics within the rated range of the sun irradiation and the temperature

Review of electrically powered propulsion for aircraft

This paper presents a review of the state-of-the-art in aircraft electrical propulsion technology. A comparison is provided of differing propulsion mechanisms such as propellers, open fans, ducted fans, multi-stage rim driven fans and distributed thrust designs and their suitability to particular flight profiles and mission applications. Electrical motor architectures are also reviewed with particular attention being given to synchronous machines, such as Brushless Direct Current (BLDC) and Switched Reluctance Motor (SRM) technologies, and the recent advances that have been made in solid-state switching and High Temperature Superconducting (HTS) material applications. Present day electrical power generation, storage and control technologies are also reviewed including hybrid and fuel cell technologies and regeneration techniques. Electrical storage capabilities with regard to specific power and energy characteristics are discussed and the extent to which existing system technology can be integrated onto a Hybrid-electric and an All Electric Aircraft (AEA) is also investigated. Finally, a conclusion is provided highlighting the current technological challenges facing the development of commercial aircraft in terms of performance, airframe configuration and legislative and operational infrastructural requirements

A review of electrical motor topologies for aircraft propulsion

This paper provides a review of the state-of-the art in aircraft electrical propulsion (AEP). Initially, the limitations of on-board energy storage devices are highlighted and contextualised. The definitions of useful measures for determining the suitability of motor design, namely specific power and motor torque per unit rotor volume (TRW), are discussed and relevant examples are provided. The classifications of motors used for terrestrial vehicle applications are reviewed and their limitations highlighted regarding their suitability to AEP applications. A discussion on motor configurations for aerospace applications is provided which includes: synchronous motor stator winding configurations; axial flux motor configurations and the causes of energy losses. Additionally, the topologies and performance characteristics of existing aerospace motor technologies are examined. It was concluded that electrical motors provide an ideal means for achieving aircraft propulsion and that higher motor speeds are likely to be required for future commercial aircraft motor designs

Modelling of a photovoltaic array using Analog System Lab Kit Pro board

This paper discusses modelling and parameters investigation of a photovoltaic array using Analog System Lab Kit Pro board offered by Texas Instrument for instructional laboratories on Electric and Electronic Engineering. The modelling of PV array is based on representation of the current-voltage characteristic by an analogue circuit developed using the components available on the Lab Kit board. The model is applicable for instructional laboratory investigation on the array current-voltage characteristic and its performance at maximum power point. This investigation expands the portfolio of the laboratory works available through Analog System Lab Kit Pro board

Reduction of short circuit current using DC transmission and split-winding power transformer

This paper discusses a new scheme to reduce the level of fault currents in the feeder cable and power transformer windings under short-circuit conditions. The proposed scheme suggests splitting the feeder cable in two cables and connecting it to a network through two rectifier units. Therefore, the split windings of the power transformer are supplied by a six-conductor feeder using unidirectional dc current. Unidirectional magnetic flux produced by the windings are summarised in the transformer core resulting ac flux to ensure a normal transformer operation. The proposed scheme was analysed under short and open-circuit faults. It has been shown that the short-circuit currents in the cable conductors and transformer windings are reduced in 1.41 times in comparison to a conventional scheme

Insulation fault detection and localisation in electric and hybrid electric vehicles

This paper discusses a method for detection and localisation of the insulation faults in electrical equipment distributed along the body of electric and hybrid electric vehicles. At the beginning of the fault detection procedure it is required that the vehicle powertrain be shut-down. The method is based on measurement and comparison of leakage currents in every device in the electrical powertrain. The leakage currents are generated by a high voltage signal generator connected between the vehicle body ground and dc-bus wires and shifting the potential between the electrical equipment and chassis. The currents are measured using a current clamp to detect the active component of the leakage current corresponding to an insulation fault. The proposed method was implemented in a prototype device used to detect an insulation fault in subway powertrains (i.e. a metro train). The method demonstrated excellent efficiency through successful detection and localisation of insulation faults

Real-time model of synchronous reluctance motor drive for laboratory based investigations

The Synchronous Reluctance Motor has received much attention in recent years as a very promising solution for electric drives in the near future. This paper presents a real-time model of the motor to be implemented into a software environment used for DSP control system development including debugging. The model is used in laboratory based investigations in academia in order to analyse the performance of electric drives based on a synchronous reluctance motor

Simulation and testing of a power converter for aircraft AC electric power generation system using software elimination of higher harmonics

This paper presents the results of simulation and practical tests of the inverter-based power converter with a sine output filter designed for implementation in an aircraft power system. In order to reduce the output voltage harmonic distortion, the converter utilises active software harmonics filtering. This work provides an analysis of the converter performance under two control algorithms applied for the active filtering operation. The first control algorithm is based on discrete Fourier transform (DFT) where the control system injects measured higher harmonics with inverse polarity into the inverter command voltage and DFT provides the measurement of the converter output voltage. The second control method is based on repetitive controller (RC) algorithms which adjusts the inverter command voltage using a self-learning approach. The second method significantly reduces the demand for CPU computational resources. The software filtering in both systems shows a good performance and ensures the converter output voltage with less than 5% THD under all load conditions. This paper discusses the structures for both proposed control systems as well as the implementation in MATLAB models and microcontroller software. Both algorithms are modelled in software and implemented in a practical microcontroller. The advantages of the RC-based control method are demonstrated through the software analysis and performance of the system

Analysis of the effects on the pitching, rolling and yawing rate of a v-tail configured quadcopter

Many different projects have been focused on multirotor aircraft, especially on quadcopters, but there are only a few papers relating to the dynamic effects on quadcopters with tilted motors. In this paper, a quadcopter has been modelled to allow flight simulation under differing motor tilt angle configurations. The simulation has also been validated by building a quadcopter of known physical attributes and with on-board instrumentation and telemetry to log its attitude and motor control inputs (PWM signals). The conversion from a PWM signal to the rpm was achieved by determining the relationship between the PWM signal and the thrust generated. Both of these parameters being recorded on a test bench. Thrust is calculated for each motor individually, since the angled motors generate different advance ratios and hence different thrust coefficients. The main focus of this research was on the effect of the different coefficients and the thrust components acting in the x-y plane of the quadcopter body frame

Housing estate energy storage feasibility for a 2050 scenario

The further penetration of renewable sources in the grid requires the implementation of energy storages in order to smooth out the variability and intermittent nature of renewables. This paper looks at the possibilities for a storage solution to meet an unprecedented situation of having no power input from renewables or an outage from grid sources for five consecutive days in the highest demand period of the year. The study uses as test case a 1000 house estate in the year 2050 with each property using electrical heating and electrical vehicle charging. The magnitude of power and energy estimated, together with the practicalities is then used to assess current storage solutions suitability and the likely possibilities of new innovations in the storage environment