Operating Instruction - Frequency Inverter 230V / 400V ... - opis.cz

Optimization of the controller parameters of the field parameter should be done in thebasic speed range. The frequency to be set should be slightly lower than the limit ofthe modulation controller selected via parameter Reference Modulation 750 so thatthe modulation controller is not active. Optimization of the Reference Flux 717 is onlyrequired in exceptional cases. The set percentage value changes the flux-formingcurrent component proportionally to the torque-forming current component. The correctionof the rated magnetizing current by means of the reference flux thus changesthe torque of the drive. If the parameter Reference Flux 717 is decreased drastically(change-over from 100% to 50%), the parameter I sd can be oscillographed. Thecourse of the signal of the flux-forming current I sd should reach the stationary valueafter overshooting without oscillation. The integral time of the field controller shouldbe selected according to the half rotor time constant calculated by the software. Theactual value to be read out via parameter Act. Rotor Time Constant 227 divided bytwo is to be used in the first approach for the parameter Integral Time Field Controller742. If a quick transition into field weakening is necessary for the application, theintegral time should be reduced. The amplification is to be selected relatively large inorder to achieve a good dynamism of the controller. Attention should be paid to thefact that an increased overshoot is necessary for a good control behavior in controllingof a load with low-pass behavior, for example a 3-phase machine.16.5.5.1 Limitation of field controllerThe output signal of the field controller, the integrating and proportional componentsare limited via parameter Ref. Isd Upper Limit 743 and parameter Ref. Isd LowerLimit 744. The guided commissioning has set the parameter Ref. Isd Upper Limit743 according to the parameter Rated Current 371.ParameterSettingsNo. Description Min. Max. Fact. sett.743 Ref. Isd Upper Limit 0.1⋅I FIN o ⋅ I FIN I FIN744 Ref. Isd Lower Limit - I FIN I FIN 0.0The limits of the field controller define not only the maximum current occurring, butalso the dynamic properties of the controller. The upper and lower limits restrict themodification speed of the machine flux and the torque resulting from it. In particularthe speed area above the nominal frequency should be observed for the modificationof the flux-forming component. The upper limit is to be estimated from the product ofthe set magnetizing current and the correction factor Reference Flux 717, althoughthe limit must not exceed the overload current of the drive.16.5.6 Modulation ControllerThe modulation controller, which is designed as an I regulator, automatically adaptsthe output value of the frequency inverter to the machine behavior in the basic speedarea and in the field weakening area. If the modulation exceeds the value set withparameter Reference Modulation 750, the field-forming current component and thusthe flux in the machine are reduced.02/06 159