Voir la source de Danfoss Drives – Learning the Basics of Variable Frequency Drives

There is popular use of alternating existing (AC) motors since it is far more value efficient and productive where speed management and important power [https://pixabay.com/en/photos/?q=output output] is necessary. Variable frequency Danfoss drives accurately handle the speed of a regular AC induction motor. By way of the Danfoss drives, pace handle with total torque can be reached from  RPM to the highest rated speed that is earlier mentioned the rated velocity at reduced torque. Variable frequency drives manipulate the frequency of output by rectifying incoming AC recent into direct existing (DC). A voltage pulse width modulation recreates the AC recent and voltage output waveform. 
Sorts of variable frequency drives
The three common varieties of variable frequency drives contain:
-Current source inversion (CSI) - is the variety of variable frequency travel that has regenerative energy functionality. In simple conditions, the CSI VFD can take in electrical power circulation again from the motor to the electrical power offer. CSI Danfoss drives have been productively used in sign processing as effectively as industrial electricity apps. 
-Pulse-width modulation (PWM) - has exceptional enter power element due to its fixed DC bus voltage. PWM variable frequency drives are commonly employed in industries because they do not lead to motor clogging at under six Hz which is the frequent dilemma with voltage resource inversion drives. PWMs are also a lot more productive and cost effective. 
-Voltage supply inversion (VSI) - is not widely utilized by industries because of the bad electricity factor.
Likely troubles encountered with variable frequency drives
A single of the most common troubles with variable frequency drives is heating because of to system harmonics. Harmonics are irregularities in the sine wave. In an perfect energy circuit globe, there must be no harmonics even so, there are approaches to mitigate harmonics. The easiest technique is by making use of a sine wave filter on possibly aspect of the Danfoss drives. Another confirmed tactic that can be used on the line side of variable frequency drives is to spot a capacitor at the frequent bus. The impedance of a capacitor that is inversely proportional to the frequency of the sign will allow harmonics to see a short through the capacitor and travel through it and overlook other hundreds on the bus. If harmonics are not appropriately mitigated on the line aspect of the Danfoss drives, troubles on crosstalk and heating could be encountered. Crosstalk signifies the signal from one circuit is interfering with the other and this is a more substantial problem than overheating. Overheating can enhance cooling fees but crosstalk can be very annoying in telecommunications. In electricity circuitry, crosstalk can trigger overheating and frequency relay trips. 
Harmonics can also lead to issues on the load aspect because of its nature as waves. Electromagnetic waves can act like a substantial amplitude sine wave that means a small sum of reactance can consequence in large voltage spikes. On the other hand, the capacitor related on the load side of the variable frequency travel can also generate extra problems like destroying a drive. Despite the fact that the techniques function effectively, it is important to be effectively educated to stay away from even more troubles from cropping up.