1 Report on Usefulness of Data Collected and Plausibility of the Electric Car s Motor Zainab Hussein April 25, 2017 Table of Contents Introduction...1 Data Collection...2 Experiment 1 constant supply current... I Experiment 2 constant load torque... II Experiment 3 constant motor speed... III Data Analysis...3 Constant Load Torque... I Constant Motor Speed... II Constant Supply Current... III Results and Conclusion...4 Appendix Dyno System Setup...5 Reference...6
Introduction The aim of this report is to analyze the usefulness of the experimental data collected in order to understand the plausibility of the Electric Vehicle motor operating in steady state. Data was analyzed to determine if the experimental behavior of the motor matched the theoretical 1 expectation of two linear and one hyperbolic relationships. Consistency between theoretical and experimental data behavior would suggest the Electric Vehicle motor is plausible for application in the Lafayette Formula Electric Vehicle. Data Collection The following experimental data was collected using the available dynamometer and sensors. All system operations are outlined and described in the Appendix. General setup for all the indexed experiment 1-3, the following steps are: a. Hooked up all cables and checked they work b. Booted the PC and ran Windows TeamViewer c. Ensured Prof. Nadovich had turned HV on and E-Stop button not closed. Supply voltage was set to 91.5V. d. Opened VirtualBox through Team viewer, then ran OpenSuse, then ran DYNO e. Click ON on the supply tab, then went to room to look in to see voltage was present at supply f. Minimized V.B momentarily and opened 1314-Programmer i. Choose data to monitor Motor RPM, Motor Temp, Controller Temperature, Dyno Torque and Supply Current ii. Ran data logger at 500ms After steps a-f, experimentation continued as follows: Experiment 1 constant supply current 1. Set the load setting to 0% 2. Adjust throttle setting to change supply current to reach a desired current, started at 0A with increments of 20A to 160A. 3. Recorded load%, motor speed (rpm), load torque (lb-ft) and the actual supply current (A) in a spreadsheet 4. Incremented load setting by 5% and repeat steps 2 and 3 until load setting of 50% For this experiment, we went to only 50% load. Experiment 2 constant load torque 1. Set the load setting to 0% 2. Adjust throttle setting to change supply current to reach a desired load torque, started at 0 lb-ft with increments of 5 lb-ft to 40 lb-ft. 2
3 3. Recorded load%, motor speed (rpm), desired load torque (lb-ft), supply current (A) and the actual load torque (lb-ft) in a spreadsheet 4. Incremented load setting by 5% and repeat steps 2 and 3 until load setting of 35% For this experiment, we went to only 35% load rather than the original 100% because of limitation of the motor heating up. Experiment 3 constant motor speed 1. Set the load setting to 0% 2. Adjust throttle setting to change supply current to reach a desired motor speed, started at 0 rpm with increments of 500 rpm to 4000 rpm. 3. Recorded load%, desired motor speed (rpm), load torque (lb-ft), supply current (A) and the actual motor speed (lb-ft) in a spreadsheet 4. Incremented load setting by 5% and repeat steps 2 and 3 until load setting of 35% For this experiment, we went to only 35% load rather than the original 100% because of limitation of the motor heating up. Data Analysis Figure 1-4 are graphs plotted from data collected at a constant 91.5V supply voltage. Constant Load Torque Figure 1 is a linear relationship is as expected, but the range of motor speed is 762 3969 rpm. The range of load torque given does not show what happens at low values of motor speed. The 35 and 40 lb-ft constant load torque only have one data point each, due to limitations of heating motor.
Motor Speed (rpm) ECE 492 4 Motor Speed vs Supply Current at constant values of Load Torque at 91.5V 4500 4000 3500 15 lb-ft 20 lb-ft 25 lb-ft 30 lb-ft 3000 10 lb-ft 2500 2000 1500 5 lb-ft 35 lb-ft 40 lb-ft 1000 500 0 0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 160.0 180.0 200.0 Supply Current (A) Figure 1 Motor speed at constant load torque Constant Motor Speed Figure 2 and 3 are a linear relationship is as expected, but the plot has been divided into constant low and high motor speed. Low motor speeds like 250 and 500 rpm correspond to very small values of torque. An optimum constant motor speed of 2500 rpm corresponds to the highest load torque of 42.2 lb-ft. Low and high motor speeds have been divided into their separate graphs because the low motor speed relation has very small ranges of supply current and load torque resulting them appearing like a smudge on a combined plot.
Load Torque (lb-ft) Mechanical Torque (ft-lb) ECE 492 5 Load Torque vs Supply Current at low constant values of Motor Speed at 91.5V 3.0 2.5 2.0 500 rpm 1.5 250 rpm 1.0 0.5 0.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 Supply Current (A) Figure 2 Load torque at constant low motor speed Load Torque vs Supply Current at high constant values of Motor Speed at 91.5V 45.0 40.0 35.0 30.0 25.0 20.0 15.0 1500 rpm 2000 rpm 2500 rpm 3000 rpm 3500 rpm 4000 rpm 10.0 5.0 1000 rpm 0.0 0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 160.0 180.0 200.0 Supply Current (A) Figure 3 Load torque at constant high motor speed
Load Torque (lb-ft) ECE 492 Constant Supply Current Figure 4 is a hyperbolic relationship is as expected. The range of load torque given does not show what happens at low values of motor speed. The load torque self-adjusts to meet the given power that is proportional to the constant current, resulting in the expected hyperbolic relationship shown.. 62.2 lb-ft was the highest load torque recorded for this entire experiment, giving a load torque range of 0-62.2 lb-ft. 6 Load Torque vs Motor Speed at constant values of Supply Current at 91.5V 70.0 60.0 50.0 40.0 30.0 140A 120A 100A 80A 60A 40A 160A 20.0 20A 10.0 0.0 0 500 1000 1500 2000 2500 3000 3500 4000 4500 Motor Speed (rpm) Figure 4 Load Torque at constant supply current Results and Conclusion The three expectations of this experiment to prove two linear relationships and one hyperbolic one. At constant current, motor speed self-adjusts at a set load torque value to meet the power which the current is proportional to, resulting in hyperbolic relationship. The two linear relationships of constant motor speed and load torque: when load torque is held constant, a set increase in motor speed results to an increase in supply current to maintain the given constant load torque. Then motor speed is held constant, at constant motor speed, a set increase in load torque results to an increase in supply current to maintain the given constant motor speed. Therefore, the experimental results are consistent with the theoretical expectations, following a mathematical model of conservation of power. The conclusion of this report is that the electric motor tested is plausible for use in the Formula Electric car.
7 Appendix - Dyno System Setup Electric Vehicle Systems HPEVS AC50515X Motor Curtis Instruments 1238R7601 Controller Battery Simulation MagnaPower(TSD 100250/208) D.C. Power Supply 20kW P.S. 200A max rms @ ~100 Vdc Dynamometer System and Sensors - Huff HTH100 Dyno Load Adjustment o Oil Valve(CAT HY143200) Torque Sensor o Load Cell (LCCE250) o Strain Gauge Input Module (DataForth SCM5B38) Tachometer o Frequency Input Module (DataForth SCM5B45) Throttle o Voltage Output Module (DataForth SCM5B49) Data Acquisition Board (MCDAQUSB7204) Data Acquisition Software Curtis 1314 Programming Software o Motor RPM data Dyno Software (Proprietary from Class of 2015) o Output Data: P.S. Current, Torque o Input Data: Load %, Throttle % Computer Dell Precision T1700 o Accessed through Windows TeamViewer o Dyno software is run using a deployment of OpenSuse in Oracle s Virtual Box Reference 1Hussein, Zainab. Theoretical relation of the Formula Electric Car Physical Parameters of Load Torque, Supply Current and Motor Speed. March 24, 2017