THREE-PHASE VSI MODELLING REVIEWĪ mathematical model of three-phase is presented here based on space vector representation. Various simulation results are also included. Finally, a MATLAB/SIMULINK model for the SVPWM is presented. This is followed by the basic principle of SVPWM. Firstly model of a three-phase inverter is presented on the basis of space vector representation.
#Svpwm matlab simulink software#
The reason for the choice of MATLAB/SIMULINK as a development tool is because it is the most important and widely used simulation software and is an integral part of a taught programme in most of the universities in Electrical/Electronics Engineering courses. The main focus of this article is to develop a simple MATLAB/SIMULINK model. This improves the harmonic performance of this method. The major advantage of SVWPM stem from the fact that there is a degree of freedom of space vector placement in a switching cycle. The SVPWM is identified as an alternative method of determination of switching pulse width and their position. Space vector modulation improves dc bus utilization by 15.15%, further digital implementation of this scheme is easier. The maximum output voltage from VSI utilizing this scheme is limited to 0.5V dc (peak) or 0.353 rms. The major disadvantage of this scheme is a lower dc bus utilization. The most popular among those are carrier-based sinusoidal PWM and SVPWM. A number of PWM techniques have been presented to obtain variable voltage and frequency supply. Executing the next two commands copies these final conditions in "xInitial" and saves this variable in a new file (myModel_init.mat).Variable voltage and frequency supply for as drives are invariably obtained from a three-phase VSI. The final states which have been saved in the "xFinal" structure with time can be used as initial states for future simulations. When simulation is completed, verify that steady state has been reached by looking at waveforms displayed on the scopes. Change the Simulation Mode from "Normal" to "Accelerator".Ĥ. Double click on the Step block labeled "Speed Setpoint (RPM)" and temporarily disable the change of reference speed by multiplying the Step time by 100.ģ. In the Simulation/Configuration Parameters/Data Import/Export Parameters menu, uncheck the "Initial state" parameter.Ģ. To regenerate the initial conditions for your modified model, follow the steps listed below:ġ. If you modify this model, or change parameter values of power components, the initial conditions stored in the "xInitial" variable will no longer be valid and Simulink® will issue an error message. When you open this model, the InitFcn callback (in the Model Properties/Callbacks) automatically loads into your workspace the contents of this. The initial states required to start this model in steady state with a 1725 rpm reference speed and a 11.9 N.m load torque have been saved in the "power_svpwm_init.mat" file. You can do a FFT of these two quantities using the powergui FFT Analysis. Stator voltage (phase AB) and phase A current waveforms can be observed in the "V-I Stator" Scope. When the motor reaches a constant speed of 1275 RPM, the stator voltage rms value is down to 165.8V and the frequency to 45.2 Hz. You can observe the system dynamic looking inside Scope 1.
![svpwm matlab simulink svpwm matlab simulink](https://ww2.mathworks.cn/help/examples/sps_product/win64/power_motordrive_IM_DTC_SVPWM_01.png)
![svpwm matlab simulink svpwm matlab simulink](https://www.mathworks.com/help/physmod/sps/powersys/ref/ac2_hl.gif)
The initial motor speed should be 1720 RPM and the rms value of the stator voltages should be 0.1s, the speed setpoint is changed from 1725 to 1300 RPM. Since the initial states have been automatically loaded, the simulation should start in steady-state.
![svpwm matlab simulink svpwm matlab simulink](https://www.mathworks.com/matlabcentral/mlc-downloads/downloads/submissions/42938/versions/1/screenshot.png)
By varying the stator voltages magnitude in proportion with frequency, the stator flux is kept constant. The magnitude and frequency of the stator voltages are set based on the speed setpoint. Speed control of the motor is performed by the "Constant V/Hz" block. The chopping frequency is set to 1980 Hz and the input reference vector to "Magnitude-Angle".
![svpwm matlab simulink svpwm matlab simulink](https://ww2.mathworks.cn/matlabcentral/mlc-downloads/downloads/submissions/44787/versions/6/screenshot.jpg)
The firing pulses to the inverter are generated by the "Space-Vector PWM modulator" block of the SPS library. The load torque applied to the machine's shaft is constant and set to its nominal value of 11.9 N.m. Its stator leakage inductance Lls is set to twice its actual value to simulate the effect of a smoothing reactor placed between the inverter and the machine. The inverter is modeled using the "Universal Bridge" block and the motor by the "Asynchronous Machine" block. A 3-phase squirrel-cage motor rated 3 HP, 220 V, 60 Hz, 1725 rpm is fed by a 3-phase MOSFET inverter connected to a DC voltage source of 325 V.