Power Electronics Application in DC Motor Drives

Project Overview

This project was developed under the EE-331 Electrical Machines course at Habib University during Spring 2020. The project explores the application of Power Electronics in DC Motor Drives. It covers the design, control strategies, and MATLAB-Simulink modeling of motor drive circuits, including AC to DC rectification and quadrant control for industrial DC motors.

REPORT: https://github.com/SarwanShah/HU_2020_Case_Study_On_DC_Motor_Drives/blob/main/Power%20Electronics%20Application%20in%20DC%20Motor%20Drives%20-%20Case%20Study%20-%20ss03595%20-%20Sarwan%20Shah.pdf

**VIDEO PRESENTATION: **

Features

• AC to DC Rectification

  • Conversion of 3-phase AC to DC using a 6-pulse rectifier.
  • Improved power delivery with reduced I²R losses and smoothed output through filtering inductors.
  • Control using thyristor-based gate firing for dynamic control of power output.

• Motor Control Strategies

  • 1-Quadrant Control: Basic motor speed control using adjustable firing angles.
  • 2-Quadrant Control: Introduction of dynamic braking and regenerative braking.
  • 4-Quadrant Control: Advanced full control over motor speed, torque, and braking, reducing reactive power consumption.

• MATLAB-Simulink Model

  • Demonstrates real-time behavior of DC motor drives with adjustable parameters.
  • Supports analysis of voltage, current, and power stress based on varying firing angles.

Project Implementation

➤ AC to DC Rectification

• Utilizes a 3-phase, 6-pulse rectifier circuit to ensure higher average DC voltage output.
• Integration of filtering inductors to maintain a steady current and reduce losses.

➤ Thyristor Control

• Thyristors operate based on gate-firing principles to modulate power delivery.
• Gate pulses synchronized with AC phase for continuous conduction over 120°.

➤ Quadrant Control

• 1-Quadrant Control: Allows for acceleration and coasting with limited control over braking.
• 2-Quadrant Control: Enables fast deceleration and reverse current flow for regenerative braking.
• 4-Quadrant Control: Employs two converters for comprehensive speed, torque, and direction control.

➤ MATLAB-Simulink Modeling

• Simulates real-world behavior of motor drives.
• Visualizes the impact of firing angles on voltage, current, and reactive power.

Design Challenges

• High reactive power consumption at greater firing angles.
• Erratic motor behavior at lower speeds due to pulsating currents.
• Complexity and cost of implementing full 4-quadrant control.

3. Adjust firing angles to observe the effects on motor speed, torque, and reactive power.

References

• Wildi, T. Electrical Machines, Drives, and Power Systems. Pearson New International Edition, 2014.
• Various studies on thyristor control and reactive power generation.