scholarly journals ELECTRICAL DRIVE AND CONTROL OF AN ELECTRIC MOTOR STEP BY STEP BY STEP BIPOLAR

2021 ◽  
Vol 2021 (2) ◽  
pp. 11-14
Author(s):  
VIOLETA-VALI CIUCUR
Keyword(s):  
Analog Circuits ◽  
Filling Factor ◽  
Pulse Width Modulation ◽  
Pulse Generator ◽  
Clock Cycle ◽  
Current Source ◽  
Maximum Benefit ◽  
Rectangular Signal ◽  
The Times ◽  
Drive And Control

"PWM, (Pulse Width Modulation) is the most effective way to control analog circuits using numerical outputs by changing the duration and frequency of the signal. The duration of each state t1 and t2, so the filling factor, where T = t1 + t2 = constant. If only one of the times (t1 or t2) varies, then the Tt period of a cycle varies, so the f = 1 / T frequency varies. The PWM signal is actually a modulated rectangular signal over the duration by modifying the duration of each period t1, t2 of the cycle as well as the change in frequency. The maximum benefit of a stepper motor can only be obtained if it is ordered correctly, this requiring a direct current source, an electronic switch and a controlled pulse generator (numerical information). The frequency of the CLOCK cycle is measured in Hz and the filling factor is measured in percentage (%). The amplitude of the output signal is constant even if the amplitude of signals producing the fill factor varies. "

scholarly journals A Neurostimulator System for Real, Sham, and Multi-Target Transcranial Magnetic Stimulation

2021 ◽  
Author(s):  
Majid Memarian Sorkhabi ◽  
Timothy Denison
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Pulse Width Modulation ◽  
Pulse Generator ◽  
Control Method ◽  
Physical Distance ◽  
Magnetic Pulse ◽  
Electronic Control ◽  
Channel Modulation ◽  
Measured System

Background: Transcranial magnetic stimulation (TMS) is a clinically effective therapeutic instrument used to modulate neural activity. Despite three decades of research, two challenging issues remain, the possibility of changing the 1) stimulated spot and 2) stimulation type (real or sham) without physically moving the coil. Objective: In this study, a second-generation programmable TMS (pTMS2) device with advanced stimulus shaping is introduced that uses a 5-level cascaded H-bridge inverter and phase-shifted pulse-width modulation (PWM). The principal idea of this research is to obtain real, sham, and multi-locus stimulation with the same TMS system. Methods: We propose a two-channel modulation-based magnetic pulse generator and a novel coil arrangement, consisting of two circular coils with a physical distance of 20 mm between the coils and a control method for modifying the effective stimulus intensity, which leads to the live steerability of the location and type of stimulation. Results: Based on the measured system performance, the stimulation profile can be steered 20 mm along a line from the centroid of the coil locations by modifying the modulation index. Conclusion: The proposed system supports electronic control of the stimulation spot without physical coil movement, resulting in tunable modulation of targets, which is a crucial step towards automated TMS machines.

scholarly journals Study of Excitation Characteristics of Traction Machine/Drive Systems

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 151
Author(s):  
Wenying Jiang ◽  
Qiqi Guo ◽  
Zhen Zhang
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Current Source ◽  
Computation Time ◽  
Voltage Source ◽  
Permanent Magnet Synchronous Machines ◽  
Current Harmonics ◽  
Influence Model ◽  
Machine Drive ◽  
Drive Systems

In order to accurately evaluate the performance of a traction machine/drive system, it is necessary to have an accurate excitation source which considers current harmonics. In this paper, four machine/drive systems with different excitation sources have been modeled, simulated, and studied to evaluate the effects on permanent magnet synchronous machines (PMSMs) from different perspectives. In Model I, the excitation is an ideal sinusoidal current source with no harmonics. Model II is excited by an ideal sinusoidal voltage source regardless of the pulse width modification’s (PWM’s) influence. Model III takes into account the influence of current harmonics under space vector pulse width modulation (SVPWM) control. Model IV is based on the equivalent circuit extraction (ECE) model (a look-up table motor model). We simulate these four models and study the characteristics of the excitation sources, based on the observations of current harmonics, torque, electromagnetic force, computation time, and efficiency. Experiments are also conducted to show that Model III allows the most precise study of the considered system. Model IV is a good substitution, providing similar results with a shorter running time.

scholarly journals Generalized space vector control for current source inverters and rectifiers

2016 ◽  
Vol 65 (2) ◽  
pp. 235-248
Author(s):  
J. Anitha Roseline ◽  
M. Senthil Kumaran ◽  
V. Rajini
Keyword(s):  
Vector Control ◽  
Pulse Width Modulation ◽  
Short Circuit ◽  
Current Source ◽  
Space Vector ◽  
Digital Implementation ◽  
Flexible Control ◽  
Medium Voltage ◽  
Converter Topology ◽  
Current Source Inverters

Abstract Current source inverters (CSI) is one of the widely used converter topology in medium voltage drive applications due to its simplicity, motor friendly waveforms and reliable short circuit protection. The current source inverters are usually fed by controlled current source rectifiers (CSR) with a large inductor to provide a constant supply current. A generalized control applicable for both CSI and CSR and their extension namely current source multilevel inverters (CSMLI) are dealt in this paper. As space vector pulse width modulation (SVPWM) features the advantages of flexible control, faster dynamic response, better DC utilization and easy digital implementation it is considered for this work. This paper generalizes SVPWM that could be applied for CSI, CSR and CSMLI. The intense computation involved in framing a generalized space vector control are discussed in detail. The algorithm includes determination of band, region, subregions and vectors. The algorithm is validated by simulation using MATLAB /SIMULINK for CSR 5, 7, 13 level CSMLI and for CSR fed CSI.

scholarly journals A Novel Three-Phase Current Source Rectifier Based on an Asymmetrical Structure to Reduce Stress on Semiconductor Devices

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3331
Author(s):  
Wang Hu ◽  
Yunxiang Xie ◽  
Zhiping Wang ◽  
Zhi Zhang
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Current Source ◽  
Line Voltage ◽  
Current Stress ◽  
Phase Current ◽  
Asymmetrical Structure ◽  
Three Phase ◽  
Step Down ◽  
Voltage Conversion

This paper presents a novel three-phase current source rectifier (CSR) for AC/DC step-down voltage conversion to reduce voltage and current stress. The proposed converter features an asymmetrical connection between upper and lower arms compared with conventional CSRs, but has the same number of devices. With the proposed asymmetrical structure and modified space vector pulse width modulation (SVPWM) scheme, half of transistors only need to withstand half of the line-to-line voltage rather than the full line-to-line voltage, and its DC link current can be shared by multiple switches in freewheeling periods. Therefore, it is able to bring about a significant reduction in voltage and current stress, allowing for an improvement in the converter without additional cost. The topological structure, operation principles, and comparative analysis are specifically presented. Finally, an experimental prototype is built up to verify the performance of the proposed converter.

A Novel RRR-SVPWM-Based Speed Controlling Mechanism for Brushless DC Motor

2017 ◽  
Vol 26 (06) ◽  
pp. 1750089 ◽  
Author(s):  
R. Velmurugan ◽  
K. Mahadevan
Keyword(s):  
High Speed ◽  
Pulse Width Modulation ◽  
Pulse Generator ◽  
Harmonic Distortion ◽  
Dc Motor ◽  
Brushless Dc Motor ◽  
Brushless Dc ◽  
Insulated Gate Bipolar Transistor ◽  
Wind Turbine System ◽  
High Efficient

Brushless DC motor (BLDCM) is a synchronous motor that contains a permanent magnet on the rotor and armature windings on the stator. It consists of the following characteristics, such as compact form, high efficient, silent operations and low maintenance. The existing BLDCM control systems have some drawbacks such as, it needs higher requirements for control algorithms, it uses more complicated electronics, it holds high noise and the initial rotor movement is not predictable. In order to overcome these issues, a new control mechanism, namely, carrier frequency rate, duty cycle ratio and pulse position range-space vector pulse width modulation (RRR-SVPWM) technique is proposed in this paper to control the speed of BLDCM. Initially, the unregulated AC from the wind turbine system is given to the input of six-legs insulated gate bipolar transistor (IGBT) circuit for converting the unregulated AC to regulated DC. Here, the pulse generator is used to generate the pulses based on certain parameters, such as input three-phase voltage, phase current and DC voltage. Hence, the proposed RRR-SVPWM technique is applied to reduce the noise and maintain a harmonics in a controlled level by placing a high-speed switches in a circuit. Finally, the speed of the BLDCM is increased and controlled by giving an output regulated AC to the motor. The experimental results evaluate the performance of the proposed system in terms of power factor (PF), displacement PF (DPF) and total harmonic distortion (THD).

Design of Constant Current Source Based on Pulse Width Modulation

2013 ◽  
Vol 645 ◽  
pp. 418-421
Author(s):  
Li Hui Sun ◽  
Shu Jing Wang ◽  
Wei Chen
Keyword(s):  
High Precision ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Current Source ◽  
Constant Current ◽  
Output Current ◽  
Constant Current Source ◽  
Current Output ◽  
High Conversion Efficiency ◽  
Working Principle

Design of the constant current source based on pulse width modulation, and its working principle are discussed. The design can adjust the output current through pulse width modulation (PWM), and realize micro regulation by feedback output which stabilizes current output. The constant current source has some advantages of high precision, stable work, high conversion efficiency.

scholarly journals Design and simulation of pulse generator for UWB based on LC-tank differential oscillators topology

2015 ◽  
Vol 18 (3) ◽  
pp. 225-241
Author(s):  
Nhan Chi Nguyen ◽  
Nghia Hoai Duong ◽  
Anh Van Dinh
Keyword(s):  
Pulse Generator ◽  
Current Source ◽  
Average Power ◽  
Cmos Technology ◽  
Negative Resistance ◽  
Ultra Wideband ◽  
Positive Gain ◽  
Average Power Consumption ◽  
Analysis Design ◽  
Lc Tank

This paper presents a detailed analysis, design and simulation of pulse generator for Ultra-Wideband (UWB) based on LC-tank differential oscillators topology. The differential oscillators with a cross-coupled NMOS pair and a tail current source are used to achieve more positive gain and generate negative resistance to the LC-tank. Besides, this oscillator is suitable for UWB high frequency and low power applications. The UWB pulse generator is composed of a simple on-off keying (OOK) modulated and LC-tank differential oscillators. The circuit of UWB pulse generator designed and simulated in 0.13 um CMOS technology. The UWB pulse generator generates a pulse for the 6 - 10 GHz UWB transmitter. Simulation results show a pulse width of 586 ps, a peak to peak amplitude pulse of 88.6 mV from the 1.2 V power supply and the die area of 0.22 mm2. The average power consumption of approximately 0.55 mW and an energy consumption of 1.1 pJ/pulse at 500 MHz pulse repetition rate (PRR) are observed.

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