# Modeling And Simulation For Voltage Sags/Swells Mitigation Using Dynamic Voltage Restorer (Dvr)

## ABSTRACT

This project describes the problem of voltage sags and swells and its severe impact on non linear loads or sensitive loads. The dynamic voltage restorer (DVR) has become popular as a cost effective solution for the protection of sensitive loads from voltage sags and swells. The control of the compensation voltages in DVR based on dqo algorithm is discussed. It first analyzes the power circuit of a DVR system in order to come up with appropriate control limitations and control targets for the compensation voltage control. The proposed control scheme is simple to design. Simulation results carried out by Matlab/Simulink verify the performance of the proposed method .

## KEYWORDS

1. DVR
2. Voltage sags
3. Voltage swells

## BLOCK DIAGRAM

Figure 1: Schematic diagram of DVR

## FLOWCHART:

Fig.2 Flow Chart Of Feed forward Control Technique For DVR Based Ob DQO Transformation

Figure 3. Three-phase voltages sag: (a)-Source voltage,(b)-Injected voltage, (c)-Load voltage

Figure.4. Single-phase voltage sag: (a)-Source voltage, (b)-Injected voltage, (c)-Load voltage

Figure.5.Three-phase voltages swell: (a)-Source voltage, (b)-Injected voltage, (c)-Load voltage

Figure. 6. Two-phase voltages swell: (a)-Source voltage, (b)-Injected voltage, (c)-Load voltage

## CONCLUSION:

The modeling and simulation of a DVR using MATLAB/SIMULINK has been presented. A control system based on dqo technique which is a scaled error of the between source side of the DVR and its reference for sags/swell correction has been presented. The simulation shows that the DVR performance is satisfactory in mitigating voltage sags/swells.

## REFERENCES:

• G. Hingorani, “Introducing Custom Power in IEEE Spectrum,” 32p, pp. 4l-48, 1995.
• IEEE Std. 1159 – 1995, “Recommended Practice for Monitoring Electric Power Quality”.
• Boonchiam and N. Mithulananthan, “Understanding of Dynamic Voltage Restorers through MATLAB Simulation,” Thammasat Int. J. Sc. Tech., Vol. 11, No. 3, July-Sept 2006.
• G. Nielsen, M. Newman, H. Nielsen,and F. Blaabjerg, “Control and testing of a dynamic voltage restorer (DVR) at medium voltage level,” IEEE Trans. Power Electron., vol. 19, no. 3,p.806, May 2004.
• Ghosh and G. Ledwich, “Power Quality Enhancement Using Custom Power Devices,” Kluwer Academic Publishers, 2002.

# Model and system simulation of Brushless DC motor based on SVPWM control

ABSTRACT:

According to the disadvantages as large torque ripple of square wave drive brushless DC motor control system, this paper adopted the sine wave drive the permanent magnet brushless DC motor control system based on the space vector pulse width modulation (SVPWM) control method. The simulation model of space vector pulse width modulation control method of the rotated speed of brushless DC motor and current double closed-loop control system is simulated and analyzed in MATLAB/SIMULINK. The simulation results have verified the reasonability and validity of the simulation model.

KEYWORDS:

1. Brushless DC motor
2. Modeling and simulation
3. Space vector pulse width modulation (SVPWM)

BLOCK DIAGRAM:

Figure 1 The overall system block diagram of BLDCM control system

EXPECTED SIMULATION RESULTS:

Figure 2 Speed information

Figure 3 Torque waveform

Figure 4 The motor stator three-phase current waveform

Figure 5 Phase A current use PWM and SVPWM control

CONCLUSION:

In this paper, the SVPWM control of BLDCM simulation model is established based on the MATLAB/SIMULINK, and used the classic speed, current double closed-loop PI control algorithm. From the output waveform, it can be seen the system corresponding speed fast, quickly achieve steady state. Plus load torque at t=0.1s, the speed happen fell but return to equilibrium state at soon. Three phase stator current waveform as nearly as sine wave. The simulation results show that the SVPWM control of BLDCM has good static and dynamic characteristics.

REFERENCES:

[1]Wu Quan-li, Huang Hong-quan. Simulation study of penmanent maagnet brushless DC motor based on PWM control. Electrical switches, Vol.5 (2010), p. 39-41

[2]Ma Ruiqing, Deng Junjun. Research on characteristic of sinusoidal current driving method for

BLDCM with hall position sensor. Micro-motor, Vol.7 (2011), p. 59-61

[3]Wang Shuhong. A control strategy of PMDC brushless motor based on SVPWM. Automation

Expo, Vol.10 (2008), p. 66-68

[4]Qiu Jianqi. SVPWM control for torque ripple attenuation of PM brushless DC motors. Small and medium-sized motor. Vol.2 (2003), p. 27-28

[5]Boyang Hu.180-Degree Commutation System of Permanent Magnet Brushless DC Motor Drive Based on Speed and Current Control.2009 Sencond International Conference on Intelligent Computation Technology and Automation,Vol.2 (2009), p. 723-726