Direct torque control: Quiz

Question 1: Doubly fed generators are today commonly used in ________ applications.
WindmillWind powerUnconventional wind turbinesWind turbine

Question 2: ________ is estimated as a cross product of estimated stator flux linkage vector and measured motor current vector.
EnergyTorqueForceAngular momentum

Question 3: Direct torque control (DTC) is one method used in variable frequency drives to control the ________ (and thus finally the speed) of three-phase AC electric motors.
ForceTorqueAngular momentumEnergy

Question 4: If either the estimated flux or torque deviates from the reference more than allowed tolerance, the ________ of the variable frequency drive are turned off and on in such a way that the flux and torque will return in their tolerance bands as fast as possible.
Semiconductor deviceTransistorBipolar junction transistorIntegrated circuit

Question 5: Stator flux linkage is estimated by ________ the stator voltages.
DerivativeContinuous functionIntegralCalculus

Question 6: Due to the inevitable errors in the voltage measurement and stator resistance estimate the ________ tend to become erroneous at low speed.
CalculusIntegralDerivativeContinuous function

Question 7: Typically the control ________ has to be performed with 10 - 30 microseconds or shorter intervals.
AlgorithmAlan TuringLogicAlgorithm characterizations

Question 8: The current and voltage measuring devices have to be high quality ones without noise and ________, because noise and slow response ruins the hysteresis control
Butterworth filterLow-pass filterElectronic filterRC circuit

Question 9: Thus no problems exist due to dc voltage ripple (________) or dc voltage transients
UpsamplingDiscrete Fourier transformNyquist–Shannon sampling theoremAliasing

Question 10: This involves calculating an estimate of the motor's magnetic flux and ________ based on the measured voltage and current of the motor.
TorqueEnergyForceAngular momentum