SIMOVERT MV Medium-Voltage Drives 660 kVA to 9100 ... - Industry

)SIMOVERT MVEngineering informationDimensioning the power section and driveWater cooling (continued)) EHHA EA BL = L A, A E E A @ M = JA HB HJD A ? L A HJA H+ 2 + 6 EJA H ) 5 ,4 A I A HL EH EL = L A2+ + ) 5 , 52 HA I I K HA+ @ K ? JEL EJO) = H A L A 6 HEF A L A M EJ H EJA H0 A = JA N ? D = C A H4 = M M = JA HI K F F O, A E E A @ M = JA HBH JD A ? L A HJA H1 A N ? D = C A H2 K F, ) $ ! # & %, H= E EL = L A 5 MI M EJ? D4 = M M = JA H@ H= EFig. 6/6Block diagram of the water-to-water cooling unit without redundancyVector controlThe Vector Control can only beused for induction motors andsingle-motor drives. Using thisclosed-loop control, a dynamicperformance similar to that of aDC drive is achieved. This ispossible due to the fact that thetorque and flux-generatingcurrent components can becontrolled independently of oneanother.Using this Vector Control,specified torques can be maintainedand effectively limited.6Closed-loop frequency control as field-oriented closed-loop control without speed encoderThis is preferably used forsingle-induction motor driveswith low up to high dynamicperformance requirements, forspeed control ranges of up to1:10, thus for a large proportionalof industrial applications,for example, extruders, largefans and centrifuges.n*RFGdn/dt+ + + M*n controllerMotor voltagepre-control, m controller, m * + +M*,* w,* wYf < f sf > f s+––+ +, w controllerCoord.converterV* Vd correctionV Stawith vectortransformationf, w act., m act.Motor modelV,+ +GatingunitDrive converter+ f slipn act. calculatedY *Flux controlMotor saturationcharacteristicsYVFig. 6/7Closed-loop frequency control: Field-oriented closed-loop control without speed encoder6/8 Siemens DA 63 · 2004