This paper presents the simulation analysis of voltage source inverters using space vector pulse width modulation (SVPWM) for controlling the speed of Permanent Magnet Synchronous Motor (PMSM). It is well known that field Oriented Control (FOC) of PMSM drive is widely preferred in high performance drive systems, owing to its unique characteristics like high efficiency, better power factor, low inertia, superior power density and high torque to volume ratio. This SVPWM scheme adjusts the speed of the motor by controlling the frequency and amplitude of the stator voltage. Moreover, this SVPWM method is an advanced intense computational modulation method with several advantages such as less harmonic content, effective utilization of DC bus and complete implementation by a single chip microprocessor, relative to other PWM modulations. Due to these much advantages, SVPWM has found increasing applications in power converters and motor control. This paper focuses on modeling, design and analysis of SVPWM fed 3-Phase Voltage Source Inverter (VSI) model, for speed control of PMSM drive using MATLAB/SIMULINK.

Performance analysis of speed control of PMSM drive with sinusoidal PWM and space vector pwm fed voltage source inverters

Based on chaos theory, a hybrid space vector pulse width modulation, Chaotic SVPWM, is proposed. The conventional SVPWM contains harmonic components with higher amplitudes around the switching frequency (fixed) whereas the proposed chaotic SVPWM is operated at chaotic period of the inverter thereby varying the switching frequency for the inverter. Because of this varying switching frequency, the peak value of harmonics got distributed over the output harmonics spectrum of the inverter, effectively suppressing the influence of harmonics and ultimately reducing the current/torque ripple of the induction motor. Furthermore, the proposed scheme is cost efficient, straightforward and can be used to suppress EMI characteristics of the inverter. The design methodology is based on a two-phase power system, but it can easily be extended for n-phase systems as well. The simulation is performed in MATLAB to validate this C-SVPWM control technique.

A Chaos Based SVPWM technique for B4 Inverter fed Two-Phase Symmetric Induction Motor for THD & EMI improvement at Low Modulation Index

This paper presents a simplified approach for the load flow study of a radial distribution network and symmetrical fault analysis. Kirchhoff’s voltage law (KVL) and Kirchhoff’s current law (KCL) are used to determine the bus voltage at each bus and the branch current respectively by using the backward and forward sweep algorithm. The branch current depends only on the current injection at neighboring bus and current in adjacent branch is calculated using backward algorithm starts from the end node of the line to the root node. The voltage calculation is done by forward algorithm which starts from the root node and move towards the end node. The symmetrical fault current and voltage at each bus after the fault is calculated by using simply the total impedance from the faulted bus to generating bus and the pre-fault voltage at faulted bus. Satisfactory simulations are performed by using MATLAB, and short circuit analysis done in ETAP Software.

Simplified Approach for Load Flow Analysis of a Radial Distribution Network and Symmetrical Fault Analysis

This paper presents a simplified approach for the load flow study of a radial distribution network and symmetrical fault analysis. Kirchhoff’s voltage law (KVL) and Kirchhoff’s current law (KCL) are used to determine the bus voltage at each bus and the branch current respectively by using the backward and forward sweep algorithm. The branch current depends only on the current injection at neighboring bus and current in adjacent branch is calculated using backward algorithm starts from the end node of the line to the root node. The voltage calculation is done by forward algorithm which starts from the root node and move towards the end node. The symmetrical fault current and voltage at each bus after the fault is calculated by using simply the total impedance from the faulted bus to generating bus and the pre-fault voltage at faulted bus. Satisfactory simulations are performed by using MATLAB, and short circuit analysis done in ETAP Software. 

State estimation is a key function (which provides creditable data from raw data supplied by measurement devices) in building adequate network models for on-line monitoring and analysis. The aim of this paper is to propose a modified algorithm for power system state estimation (PSSE). PSSE consist of topology process, observability analysis, state estimation (SE) solution and bad data process. In practice, after bad data/ measurement identification, bad measurement is removed from measurement set and system observability analysis is performed again. If the system is observable, SE solution is obtained. This process repeats until there is no bad measurement or no chance to remove bad measurement which causes to divergence solution. It is time taking process. In this paper, with the help of critical measurements identification existing algorithm is modified to avoid unnecessary repetitions of algorithm steps to make the algorithm simple. IEEE 14 bus, 30 bus and 118 bus systems are used for calculations and the simulation results are summarized.

A Modified Algorithm for Power System State Estimation

The radial network is the one which passes through the network without any connection to other supply. It is used for isolated loads like rural areas. Different forward-backward sweep algorithms exist for the load flow analysis of radial distribution systems. A new method of load flow analysis for radial distribution system is explained in this paper. This method is worked out by considering voltage independent loads and voltage dependency loads. The voltage profile results of the proposed method are compared with ratio flow method. Adequate simulations are performed by using Matlab.

A simple load flow method for radial distribution system

Improved dc bus utilization of voltage and its easier realization in digital domain has made Space Vector Pulse Width Modulation (SVPWM) quite popular in AC drives application. The classical Space vector pulse width modulation involves sector calculation and region estimation which results in more computational burden and complexity. A new simplified and generalized SVPWM algorithm is developed for a cascaded H bridge multilevel inverter using sampled values of reference phase voltages. The discussed method has a close similarity with Sinusoidal Pulse Width Modulation (SPWM). Implementation of the proposed SVPWM is not laborious and extension to n level is simple and straight forward. The proposed method is validated using a five level cascaded H bridge multilevel inverter driving an Induction motor.

Prabhakar Karthikeyan

Papers

A simple load flow method for radial distribution system

A simplified space vector pulse width modulation technique for multilevel inverter fed induction motor drive

Reconfiguration of Distribution System Feeder Using Slope Criterion