Description In this assignment, you will work through several tasks within the study of the Electric Drives module to perform calculations and simulations in MATLAB/Simulink. You are expected to compare your results with the laboratory data provided in the below section and complete the tasks as appropriate. Introduction The torque of an asynchronous motor is a result of the interaction of flux and rotor flux. At a rated frequency, if the voltage is set to a certain value and only reduces the frequency, then therewill be a large magnetic flux and magnetic circuit saturation (severely, it will burn the motor). Therefore, the frequency and voltage must be changed proportionally. When changing the frequency, the output voltage of the AC drive should be controlled, to keep constant flux and avoid weak magnetic and magnetic saturation phenomena. The AC induction motor is somewhat more complex, to overcome its poor transient behaviour. L1 ULIL L2 L3 +U₁ Q1 Q3 Q5 R1 R2 R3 14 R4 K1 R5 14 Up R6 Q2 Q4 Q6 -Up Fig.1. Circuit diagram U V M W 3-Y Pair of poles, P = 2 Referring to the circuit diagram in Fig. 1, you are required to deliver the following tasks: 1. As a motor control engineer, how would you apply computational and analytical techniques to devise a strategy preventing high current in the lower speed range of a motor, specifically in relation to minimum voltage boosting? Discuss the limitations associated with the techniques employed. Support your answer from the technical literature. 2. Perform and describe the simulation model in MATLAB/Simulink software you would employ to obtain the speed/torque characteristics of a motor using the altered V/f characteristics at frequencies of 15, 30, 50, 65, and 80 Hz, based on the experimental setup in Fig. 1. Discuss the results. 3. In the context of the simulation in Fig. 1, how would you select and apply equipment and engineering technologies to obtain the speed/torque characteristics of the pump/ventilator at frequencies of 15, 30, and 50 Hz for both V/f and V/f2 characteristics? Discuss the results and the limitations of the chosen technologies. 4. From the data on the motor nameplate given in Fig. 2 and ignoring core, friction, windage, and stray losses, plot a torque-speed curve, and output power-speed curve for this motor, at rated terminal voltage and frequency. 5. Determine the torque, voltage, and current in the phase winding U for various frequencies in both standard and 87 Hz configurations under torque control. By using the appropriate software packages (MATLAB or Excel) to plot the graphs, analyse and explain, how measured torque and currents respond in operating points for the standard connection and 87 Hz configuration with a maximum corner frequency of 50 Hz. Evaluate the advantages and disadvantages of the 87 Hz method for actual industrial use, considering the complexities and uncertainties involved. VDE 0530 A/Y U: LN Lucas-Nuelle GmbH Germany-50170 Kerpen - Siemensstr. 2 SE2673-1H Mot. DS IP: 20 Is.KI. : F 230/400 VI: 4,15/2,4 A 1 kW cos: 1410 1/min f: 0,74 50 Hz 100 81,4% IE2 175 81,4% Made in Germany so 79,2% Fig. 2. Motor nameplate You are expected to perform independent research and further study as appropriate to aid completion. 3 Laboratory data results using Lucas-Nuelle: a) No-load Frequency (Hz) Max Torque (Nm) Speed (RPM) 15 4.0 440 30 4.2 890 50 4.4 1500 65 2.8 1950 80 1.9 2390 Table a b) For Pump An ActiveServo software was used to calculate the power factor and efficiency for the various frequency as shown in the table below. Frequency (Hz) 15 30 50 Load Torque Speed Power Factor Efficiency (Nm) (RPM) (cos) (%) 0.2 440 0.15 24 0.8 890 0.67 61 2.1 1410 0.87 75 Table b c) Operating Points with 87 Hz Configuration Frequency n(Syn) n(Bem) M Uuv lu (Hz) (per min) (per min) (Nm) (V) (A) 10 300 210 7.3 89 2.8 20 600 510 7.2 167 2.5 30 900 810 7.3 242 2.6 40 1200 1110 7.3 320 2.6 50 1500 1410 7.3 395 2.6 60 1800 1710 5.4 395 2.1 70 2100 2010 4.1 395 1.8 80 2400 2310 3.2 395 1.6 90 2700 2610 2.5 400 1.4 100 3000 2910 1.9 400 1.3 Table c n(Syn) is the synchronous speed of the motor; n(Bem) is the rated speed of the motor for the operating point according to its rated data; M is the motor torque; Uuv is the motor voltage between U and V-phase windings; lu is the motor current in the U-phase winding.