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COURSE DESCRIPTION |
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1) Electrical Drives |
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DC DRIVES – Characteristics of DC machines. Speed regulation by armature voltage control and by excitation current control. Maximum torque and maximum power as function of the cooling system. Constant torque and constant power operation. Performance of DC drives supplied by AC-DC converters and DC-DC choppers. Starting, braking, two-quadrant operation, four quadrant operation. Industrial applications. SYNCHRONOUS MOTOR DRIVES – Cylindrical and salient-pole machines. Analysis of different rotor topologies with permanent magnet field excitation. Voltage equation, torque equation and steady-state equivalent circuit. Self starting synchronous motors. Variable speed drives. Open loop volts/hertz control. Closed loop control. Motor power factor control. Field oriented control of permanent magnet synchronous motors. Industrial applications. INDUCTION MOTOR DRIVES – Equivalent circuit in steady state. Voltage and torque equations. Approximate equivalent circuit. Voltage and torque equations. Torque-slip characteristics. Pole changing. Speed control by supply voltage variation. Speed control by slip-recovery scheme. Variable-frequency, variable-voltage induction motor drives. Constant terminal volts/hertz operation. Open-loop speed control, closed-loop speed control. Low frequency performance with increased volts/hertz. Constant airgap flux operation. The current source inverter drive with slip frequency control. The current controlled PWM inverter drive with slip frequency control. Constant power operation. Industrial applications. BRUSHLESS DC MOTORS – Fundamental machine features. MMF and flux-density diagrams. Torque and induced rotational voltage. The three-phase full-wave brushless DC motor. Position sensors. Drive characteristics and control principles. The current-controlled brushless DC motor servo drive. Application of brushless DC motors. STEPPING MOTORS – Construction and functional aspects. The variable-reluctance stepping motor. The permanent magnet stepping motor. The hybrid stepping motor. Discrete step movement. Simplified model of stepping motors. Drive characteristics and control principle. Torque-speed analysis. Application of stepping motors. |
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2) Dynamic Behavior of Electrical Drives |
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DC DRIVES - DC motor model for transient analysis. Electromechanical transient analysis with voltage control. Current controlled DC motors. Closed loop speed control. Torque regulator and speed regulator parameters. Performance of DC drives supplied by controlled rectifiers. Performance of DC drives supplied by DC choppers. Simulation of DC drives with Simulink toolbox of MATLAB. SYNCHRONOUS MOTOR DRIVES - The d-q model of synchronous motors with surface-mounted permanent magnets. Field oriented control of PM synchronous motors. Performance analysis taking into account the current limit and the voltage limit. Flux weakening operation limit. The d-q model of synchronous motors with interior permanent magnets. Performance analysis taking into account the current limit and the voltage limit. Maximum torque operation. Flux weakening operation and control principles. Simulation of synchronous motor drives with Simulink toolbox of MATLAB. Application of synchronous motor drives. INDUCTION MOTOR DRIVES - The d-q model of induction motors. Stator voltage equations in a stator reference frame, in a rotor reference frame and in a synchronous reference frame. Stator voltage equations in the rotor-flux oriented reference frame. Decoupling circuits in the rotor-flux oriented reference frame. Rotor voltage equations, flux models, expression of the electromagnetic torque. Direct scheme for the implementation of the torque control. Parameter detuning effects. Flux observers. Indirect scheme for the implementation of the torque control. Parameter detuning effects. Direct torque control of induction motors. Discrete Space Vector modulation for the direct torque control of induction motors. Performance analysis taking into account the current limit and the voltage limit. Maximum torque operation. Flux weakening operation and control principles. Simulation of synchronous motor drives with Simulink toolbox of MATLAB. Application of synchronous motor drives. SWITCHED RELUCTANCE MOTORS - Construction and functional aspects. Stator voltage equation. Electromagnetic torque. Single pulse operation. Starting and low speed operation. PWM current control. Drive characteristics and control principle. Application of switched reluctance motors. Simulation of switched reluctance motor drives with Simulink toolbox of MATLAB. Application switched reluctance motor drives. |
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3) Electromechanical Systems Modelling |
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INTRODUCTION – Electromechanical energy conversion principles. Typical load torque/speed curves. Motor/mechanical load match. Load dynamics and stability.ELECTRIC MOTORS FOR DRIVES - Construction and functional aspects of DC motors, induction motors and synchronous motors. Copper losses and iron losses. DC MOTORS – Fundamental machine feature. Wound and permanent magnet field systems. Voltage and torque equations. Equivalent circuit. Steady-state performance characteristics. Motoring and generating action. INDUCTION MOTORS - Fundamental machine feature. AC distributed windings. Voltage and torque equations. Equivalent circuit. Torque/slip characteristic. Approximate equivalent circuit. Steady-state performance characteristics. Motoring and generating action. SYNCHRONOUS MOTORS - Fundamental machine feature. Cylindrical rotor machine. Salient pole machine. Excitation systems. Voltage and torque equations. Equivalent circuit. Steady-state performance characteristics. Motoring and generating action. |
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4) Electrical Machines and Drives |
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DC MOTOR DRIVES - variable armature voltage operation. Torque control. Speed control. Two- and four-quadrant operation. BRUSHLESS DC MOTORS DRIVES - the current-controlled brushless DC motor drive. Drive characteristics and control principles. Analysis of the torque ripple. INDUCTION MOTOR DRIVES - Scalar control methods. Induction machine dynamic model. Voltage and torque equations. Direct and indirect method of vector control. SYNCHRONOUS MOTOR DRIVES - Types of synchronous machines. Scalar control methods. Open loop and closed loop control. Dynamic model. Field-oriented control of permanent magnet synchronous motors. Control principles of synchronous reluctance motors. STEPPING MOTOR DRIVES - Variable-reluctance and Hybrid stepping motors. Drive circuits. Low-speed instability. SWITCHED-RELUCTANCE MOTOR DRIVES - Single-pulse operation. Low-speed chopping mode operation. Control strategies. APPLICATIONS – Application of electrical drives. Comparison. Characteristics of linear and rotating direct actuators. |
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