Automatic Phase Advancing in a Stand-Alone Switched Reluctance Generator at Different High Speeds for Desired Output Voltage

The switched reluctance motor is a singly excited, doubly salient machine which can be used in generation mode by selecting the proper firing angles of the phases. Due to its robustness, it has the potential and the ability to become one the generators to be used in harsh environment. This paper presents an energy conversion by a Switched Reluctance Generator (SRG) when bifilar converter circuit and discrete position sensors are employed. As the generator’s speed increases by a prime mover the shape of current waveform changes in such a way that limits the production of generating voltage. At high speeds, it is possible for the phase current never reaches the desired value to produce enough back-emf for sufficient voltage generation, therefore, the output power falls off. In order to remedy this problem, the phase turn on angle is advanced in a way that the phase commutation begins sooner. Since one of the advantages of this type of generator is its variable speed then, the amount of advancing for the turn on angle should be accomplished automatically to obtain the desired output voltage according to the speed of the generator, meaning, as the generator speed increases so should the turn on angle and vice versa. In this respect, this paper introduces an electronic circuit in conjunction with the position sensors and the drive converter to achieve this task for a desired output voltage when a SRG feeding a resistive load. To evaluate the generator performance, two types of analysis, namely numerical technique and experimental studies have been utilized on a 6 by 4, 30 V, SRG. In the numerical analysis, due to highly non-linear nature of the motor, a three dimensional finite element analysis is employed, whereas in the experimental study, a proto-type generator and its circuitries have been built and tested using bifilar converter. A linear analysis of the current waveform for the generator under different advancements of the turn on angle has been performed numerically and experimentally and the results are presented

New Modified C-dump Drivers With PI Capacitor Bridge for Switched Reluctance Motor

Switched Reluctance Motors (SRM) are known as uncomplicated structure machines, have some characteristics which make them remarkable for high speed low voltage applications. Due to have full utilization of SRNI performance, attain to efficient drive circuit for this kind of motors is desirable. In this paper, a new class of modified C-dump drivers with PI Capacitor Bridge for switched reluctance motors is proposed. This new drive circuits take the advantage of having faster rate of energy discharge from each phase windings and an energy recovery circuit. Faster rate of fall for phase current permits the motor to operate at higher speed and also prevents the motor to work at saturation mode. This feature improves motors torque profile because of phase's demagnetization. To have better consideration about this new class of C-dump drive circuit, simulation analysis for proposed PI Capacitor Bridge C-Dump drive circuit is carried out

A New Class of Resonant Discharge Drive Topology for Switched Reluctance Motor

Switched reluctance motor (SRM) drive has a remarkable characteristic, high efficiency, and good controllability, which makes it attractive for high-speed applications. In this paper, the basic control strategy for a switched reluctance motor drive circuit is explained and then three different resonant discharge topologies for SRM drive circuit are proposed. Due to resonantly discharging of excess energy, these topologies provide faster rate of fall for the phase current, which permits the motor to operate at higher speeds. In the new circuits a capacitor is charged resonantly by the use of motor phase windings during the phase turn off periods and then discharged via an inductor and a diode during the next working strokes. Three different drive circuits utilizing this process are proposed. A detailed explanation and demonstration of the converter circuits have been presented

Magnetostatic Analysis of a Novel Three Phase 6/4 Two Layer Field-Assisted Switched Reluctance Generator

Switched Reluctance Machine is applied for many industry applications because it has simple structure, high variable speed range. This paper is proposed a novel three phase 6/4 two layer field-assisted Switched Reluctance Generator (SRG). This generator consists of two magnetically dependent stator and rotor sets. The magnetostatic analysis includes mathematical and simulation analysis using Finite Element Method (FEM) is carried out in this study

Different diode configurations evaluation in photovoltaic arrays using binary coding method

This paper used a robust mathematical way (binary coding method) to study shadow effect in photovoltaic arrays. Binary coding method provides a way to define power generation index (PGI) as a factor which shows the performance of arrays at shadow condition. Different configurations of photovoltaic (PV) array show different behavior at shadow condition. Configurations behavior depends on modules interconnections, bypass and blocking diodes, and etc. Configuration which has better working condition should be chosen for PV array. In this paper all conventional configurations are analyzed and compared by the use of PGI value. Over currents which may create in some states of shadow is studied. Moreover, this paper deals with influence of working voltage range of inverter in maximum power point tracking. Finally, configurations are rated

A Simple and Novel Modulation Technique Used to Obtain Output Voltage Having a Frequency Multiple of Input Voltage Frequency

This paper introduces a new modulation method that can be adopted to obtain various possible output voltages depending on the switching topology and the voltage inputs available. This method is used to obtain a sinusoidal voltage waveform with a frequency which is a multiple of the frequency of the sinusoidal input voltage. There are various applications that need a variable frequency input and a limitation is that three-phase supply is not always available. A good example to this would be single-phase induction motors. Using this method single-phase induction motors can be supplied with a variable frequency source which uses a single-phase fixed-frequency supply and so it can be used in variable speed applications. First the general idea behind this method is explained and its equations and constraint are derived. Next the technique is used to produce the desired voltage that was mentioned and the proper switching topology is explained. Then the method and its equations and constraints arc fully discussed over this particular case. Finally the simulation results are presented and analyzed

Numerical and Experimental Investigation of an Improved Flux Path Brushless-DC Machine for Variable Speed Applications

© 2015 IEEE. In this paper, analysis of an improved axially flux path brushless-dc machine (IAFP-BLDM) with the enhanced housing including its operation principle and particular structure is presented. The proposed configuration efficiently improves the magnetic performance by reducing the reluctance and leakage flux. Moreover, unlike the conventional brushless-dc generators, the proposed configuration of this paper utilizes an assisted dc field coil replaced with the permanent-magnet excitation. As the main salient feature of including the dc field coil which increases the controllability of the flux, providing a regulated terminal voltage in a very wide range appropriate for variable speed applications can be addressed. In this paper, by employing the finite-element method, the 3-D magnetic field analysis of the IAFP-BLDM is carried out by using the MagNet CAD package (Infolytica Corporation Ltd.). In order to verify the actual performance of the proposed configuration, a 1.5 kW, 3600 rpm, 9-6 salient poles and two layers are manufactured and tested followed by a discussion on the results. The output results were in good agreement with the analysis results, and also the output performance was verified by the experiment set