Category: Control of Electrical Drives

Phase Locked Loop Control

Phase Locked Loop Control(PLL): A PI controller ideally should provide perfect speed regulation. However, due to imperfections in sensing and control circuits, the closed-loop schemes described earlier can at best achieve a speed regulatio of 0.2%. The Phase Locked Loop Control (PLL) can achieve a speed regulation as low as 0.002% which can be useful […]

Current Sensing of Electrical Drives

Current Sensing of Electrical Drives: Current Sensing of Electrical Drives is required for the implementation of current limit control, inner current control loop of closed-loop speed control, closed-loop torque control of a dc drive, for sensing fault conditions, and for sensing speed in dc drives by back emf sensing method. In order to avoid interaction […]

Closed Loop Speed Control of Multi Motor Drives

Closed Loop Speed Control of Multi Motor Drives: When mechanical part of the load is of large physical dimension it becomes desirable to share the load between several motors. For example a rotary printing press usually has several printing stations which are mechanically coupled by a long drive shaft. Each section (printing station) is driven […]

Closed Loop Torque Control of Drives

Closed Loop Torque Control of Drives: Closed Loop Torque Control of Drives scheme of Fig. 3.4 finds application in battery operated vehicles, rail cars and electric trains. Driver presses the accelerator to set torque reference T*. Through Closed Loop Torque Control of Drives, the actual motor torque T follows torque reference T*. Speed feedback loop […]

Current Limit Control of Drives

Current Limit Control of Drives: Current Limit Control of Drives scheme of Fig. 3.3 is employed to limit the converter and motor current below a safe limit during transient operations. It has a current feedback loop with a threshold logic circuit. As long as the current is within a set maximum value, feedback loop does […]

Speed Control and Drive Classification

Speed Control and Drive Classification: Speed Control and Drive Classification are the Drivers where the driving motor runs at a nearly fixed speed are known as Constant Speed or Single Speed Drives. Multi-speed drives are those which operate at discrete speed settings. Drives needing stepless change in speed and multispeed drives are called Variable Speed […]

Modes of Operation of Electrical Drive

Modes of Operation of Electrical Drive: Three types of Modes of Operation of Electrical Drive: Steady-State Acceleration including starting Deceleration including stopping As we know already, steady-state operation takes place when motor torque equals the load torque. The steady-state operation for a given speed is realized by the adjustment of steady-state motor speed-torque curve such […]