Permanent magnet generators for renewable energy devices with wide speed range and pulsating power delivery

This paper describes the design of a direct-drive permanent-magnet generator for use in a novel sea-wave electrical generator. The basic system is briefly described and the target specification derived from the device and the wave tank performance. The design for the brushless permanent-magnet generators is then developed using SPEED PC-BDC and verified using Finite Element Analysis (PC-FEA). A diode bridge model is also tested using Portunus system simulation. Copyright © 2009 Inderscience Enterprises Ltd

Matrix analysis techniques in cage induction machines

Modern analysis techniques for electrical machines are either analytical or use finite element analysis. Both methods are implemented using computational techniques to solve the magnetic circuit and produce performance predictions. This paper puts forward a steady-state impedance matrix method for analysing a split-phase induction machine that is at the leading edge of analytical modelling of induction motors. The method is implemented and verified against an example to illustrate the asynchronous torques in a non-sinusoidal winding. In the second half of the paper it is shown how the technique can be applied to a three-phase machine and the classical per-phase model is obtained from the derivation. The steady-state model derives a mathematical rigorous equivalent circuit that includes the skew reactance term in the rotor circuit. Copyright © 2009 Inderscience Enterprises Ltd

Improved Direct Torque Control method of brushless doubly-fed reluctance machines for wind turbine

Direct Torque Control (DTC) method is an excellent technique for torque and flux control for a brushless doubly-fed reluctance machine (BDFRM). The advantages of the DTC method are simple implementation, fast response and little dependence on the machine parameters. However, the conventional DTC method has high torque and flux ripple and variable switching frequency problems. This paper proposes an improved DTC method for the BDFRM when used in wind power generation systems. The Space Vector Modulation (SVM) method is used for reducing the torque and flux ripple, and also for holding constant the switching frequency of the inverter. The control method is implemented in SIMULINK®/MATLAB® and the results show that the proposed DTC method can overcome the issues and problems associated with the conventional DTC method and improve the system operation performance. © 2013 IEEE

Brushless permanent magnet DC and AC motor and synchonous reluctance motor design for racing motorcycles

There is an increasing interest in electric transportation. Most large manufacturers now produce hybrid versions of their popular models and in some countries electric cycles and scooter are now popular. Motor sport is often used to develop technology and in this paper designs for electric racing motorcycles are addressed. These are in-frame motors (rather than hub motors which can affect handling and are not as powerful). Typically 10 to 12 kW-hours of batteries can be carried on the cycle and the batteries are almost exhausted at the end of a race. Therefore very high efficiency over a range of operation is needed, but also the motors need to be compact and have high torque density. This paper examines the use of permanent magnet motors and possible designs. © 2013 IEEE

Fault ride-through of doubly-fed induction generator with converter protection schemes

This paper from the point view of wind farm fault ride-through (FRT) capability, discusses the performance of converter protection schemes to it. Different resistor protection methods are summarized and then a new combined protection with crowbar (CB) and series dynamic resistor (SDR) is proposed. With the analysis of rotor current during fault, resistance values are calculated for practical application. The rotor high current reduction performance is simulated with MATLAB/Simulink. Fault ride-through performance including the reactive power supply, torque fluctuation and rotor speed with crowbar and series dynamic resistor are compared. The proposed method is an alternative for further protection and requirements of wind farm riding-through grid disturbances. Index Terms-Fault ride-through (FRT), Doubly-fed induction generator (DFIG), converter protection, wind generation. © 2008 IEEE

A small segmented oscillating water column using a savonius rotor turbine

This paper outlines a project which addresses the use of a small segmented oscillating water column with three sections. The turbine utilises cascaded Savonius rotors (one for each section) and this system is developed and tested for validation of the performance algorithms. It is shown that the systems can be easily described and a system developed that can generate. It would be suitable for a shoreline location such as a harbour wall, where waves are random and not orthogonal to the column. Conversion rates in the region of 20 % are tabulated for the system with an output of 25 W peak. The paper will give a full algorithm for the system while the digest outlines some crucial points with regards to the sizing and operation of the column with respect to the wave frequency and wavelength. The turbine is fully characterized - the generator is a brushless permanent magnet machine connected to a diode bridge rectifier and variable load. © 2008 IEEE

Rotor fault analysis in a doubly-fed induction generator using impedance matrix technique

© 2017 IEEE. Condition monitoring is a standard method for scheduling maintenance and ensuring that catastrophic failures do not occur in industrial motors

Leveraging smart meter data for economic optimization of residential photovoltaics under existing tariff structures and incentive schemes

© 2017 Elsevier Ltd The introduction of smart grid technologies and the impending removal of incentive schemes is likely to complicate the cost-effective selection and integration of residential PV systems in the future. With the widespread integration of smart meters, consumers can leverage the high temporal resolution of energy consumption data to optimize a PV system based on their individual circumstances. In this article, such an optimization strategy is developed to enable the optimal selection of size, tilt, azimuth and retail electricity plan for a residential PV system based on hourly consumption data. Hourly solar insolation and PV array generation models are presented as the principal components of the underlying objective function. A net present value analysis of the potential monetary savings is considered and set as the optimization objective. A particle swarm optimization algorithm is utilized, modified to include a penalty function in order to handle associated constraints. The optimization problem is applied to real-world Australian consumption data to establish the economic performance and characteristics of the optimized systems. For all customers assessed, an optimized PV system producing a positive economic benefit could be found. However not all investment options were found to be desirable with at most 77.5% of customers yielding an acceptable rate of return. For the customers assessed, the mean PV system size was found to be 2 kW less than the mean size of actual systems installed in the assessed locations during 2015 and 2016. Over-sizing of systems was found to significantly reduce the potential net benefit of residential PV from an investor's perspective. The results presented in this article highlight the necessity for economic performance optimization to be routinely implemented for small-scale residential PV under current regulatory and future smart grid operating environments

Applications of the direct space vector modulation controlled matrix converter as the unified power flow controller

© 2016, Institution of Engineering and Technology. All rights reserved. This paper investigates the matrix converter when working as the unified power flow controller which can regulate the active reactive power flowing in a transmission line. A conventional unified power flow controller usually has a DC capacitor; this is removed in the proposed controller. This reduces the volume, improves the efficiency and lifetime, and eliminates the DC voltage control. The detailed direct space vector modulation method for the matrix converter is described. Based on this modulation scheme, a PID controller is designed in order to control the power flow. Coupling effects are suppressed by feedback of the coupling components to the controller. The proposed strategy can control the active and reactive power efficiently and effectively. Simulations based on MATLAB/Simulink help verify the feasibility and effectiveness of the scheme