Danfoss VLT AQUA Drive FC 202 Design Manual

Also see for VLT AQUA Drive FC 202: Service guide Installation guide Installation guide Operating guide Installation guide

Contents

There are 3 types of closed-loop control:• Speed control. This type of control requires a speed PID feedback for an input. A properly optimized speed closed-loop control has higher accuracy than a speed open-loop control. The speed control selects which input to use asspeed PID feedback in parameter 7-00 Speed PID Feedback Source.• Torque control. Used in flux mode with encoder feedback, this control offers superior performance in all 4quadrants and at all motor speeds.The torque control function is used in applications where the torque on the motor output shaft is controlling theapplication as tension control. Torque control is selected in parameter 1-00 Configuration Mode, either in [4] VVC+open loop or [2] Flux control closed loop with motor speed feedback. Torque setting is done by setting an analog,digital, or bus-controlled reference. The maximum speed limit factor is set in parameter 4-21 Speed Limit FactorSource. When running torque control, it is recommended to make a full AMA procedure since the correct motordata is essential for optimal performance.• Process control. Used to control application parameters that can be measured by different sensors (pressure,temperature, and flow) and be affected by the connected motor through a pump or fan.P 20-81PID Normal/InverseControlPIDRef.HandlingFeedbackHandlingScale tospeedP 4-10Motor speeddirectionTo motorcontrol(Illustra-tion)(Illustra-tion)130BA359.12100%0%-100%100%*[-1]_+Illustration 11.7 Block Diagram of Closed-loop ControllerProgrammable featuresWhile the default values for the drive in closed loop often provide satisfactory performance, system control can often beoptimized by tuning the PID parameters. Auto tuning is provided for this optimization.• Inverse regulation - motor speed increases when a feedback signal is high.• Start-up frequency - lets the system quickly reach an operating status before the PID controller takes over.• Built-in lowpass filter - reduces feedback signal noise.11.2.7 Control ProcessingSee Active/Inactive Parameters in Different Drive Control Modes in the programming guide for an overview of which controlconfiguration is available for your application, depending on selection of AC motor or PM non-salient motor.Basic Operating Principles ... Design GuideMG22B102 Danfoss A/S © 05/2017 All rights reserved. 10511 11