Hardware-in-the-Loop Testing For Electric Vehicle Drive Applications
Hardware-in-the-Loop Testing for Electric VehicleDrive ApplicationsJason J. Poon, Michel A. Kinsy, Nathan A. Pallo, Srinivas Devadas, Ivan L. CelanovicMassachusetts Institute of TechnologyCambridge, MassachusettsEmail: jsn@mit.eduAbstract—This paper describes the design, implementation,and validation of a hardware-in-the-loop (HIL) test platform forelectric vehicle drive applications. We implement a HIL platformby interfacing a variable speed drive controller with a real-timesimulation of an electric vehicle drive. A real-time test bench simulation enables drive cycle testing and fault injection capabilityfor the HIL platform. We demonstrate the prototyping capabilityof the HIL platform with the EPA Urban Dynamometer DrivingSchedule (UDDS) on an electric vehicle drive system. Real-timecomparisons with a real, small-scale electric vehicle drive validatethe fidelity of the real-time simulation under various operatingand fault conditions. Test case simulations demonstrate thefidelity and prototyping capability of the hardware-in-the-loopplatform when used for electric vehicle drive testing applications.Additionally, real-time simulation and test results demonstratethe ability of the HIL platform to accurately encapsulate electricvehicle dynamics with time constants that span more than fiveorders of magnitude.Index Terms—electric vehicles, power system simulation,power system faults, field programmable gate arrays, DC-ACpower converters, vehicle dynamics, system testing, variablespeed drivesI. I NTRODUCTIONIn recent years, hardware-in-the-loop (HIL) testing hasshown significant promise to serve as a comprehensive rapidprototyping and automated testing platform for advancedpower systems. HIL testing is a technique that replaces aphysical model, such as an electric vehicle drivetrain, with amathematical representation that fully describes the importantdynamics of the physical model. Figure 1 shows a functionalblock diagram of the hardware-in-the-loop concept. A deviceunder-test, such as an embedded controller or electronic control unit (ECU), interfaces directly with a low-latency realtime computing platform that computes the response of thephysical system. A test bench simulation provides the abilityto inject test cycles and faults into the real-time simulation,which enables the device-under-test controller to be tested witha wide range of normal and fault operating conditions [1].Hardware-in-the-loop enables the testing of closed-loopdevice-under-test controllers under realistic operating conditions without the need to interface with a high-power system.HIL tools enable: (1) accelerated testing and validation; (2)reduced testing time needed in the lab; (3) simulation of alloperating points and scenarios that are difficult or impossibleto recreate with a real system; (4) fault injection capability;(5) real-time access to all signals that are difficult to measure978-1-4577-1216-6/12/ 26.00 2012 IEEE'HYLFH XQGHU WHVW '87&RQWURO VLJQDOV&RQWURO OD\HU5HDO WLPH VLPXODWLRQ OD\HU)HHGEDFN VLJQDOV3RZHU HOHFWURQLFV VLPXODWLRQ(QYLURQPHQW YDULDEOHV7HVW EHQFK VLPXODWLRQFig. 1. An overview of the hardware-in-the-loop concept. A device-under-testcontrol layer interfaces with a real-time simulation layer.in a real system [1], [2]. Existing hardware-in-the-loop toolshave been used to test and prototype systems with slowerdynamics, including power grid dynamics [3], [4] and powersystem dynamics [5]–[9].However, current state-of-the-art HIL tools have been insufficient for prototyping power electronics converters, whichare becoming ubiquitous in energy conversion and powerprocessing devices. A power electronics HIL environment canprovide a rapid prototyping platform for the design and testingof power electronics hardware, software, and firmware. Powerelectronics converters, unlike power systems, are characterizedby high-frequency switching devices, including controlledswitches (e.g. IGBTs, MOSFETs, thyristors, SCRs) and selfcommutating switches (e.g. diodes) that operate on the orderof 10 kHz. Furthermore, these switching devices introducedifferential and common mode voltages and currents at frequencies on the order of 1 MHz and above. Indeed, a realtime simulation of a power electronics converter with a carrierfrequency on the order of 20 kHz requires a sampling timeless than 5 μs to capture the important system dynamics [10].However, the non-linear switching dynamics has posed achallenge for low-latency, real-time simulation of power electronics converters. Existing simulators for power electronicsare limited by a sampling time between 10 to 50 μs for realtime execution [11]–[13], or do not have the ability to beexecuted in real-time [14]–[16].In [17], [18], we have presented a flexible field programmable gate array (FPGA) environment that solves piecewise linear state-space system models of power electronicsconverters with a fixed 1 μs simulation time step, including2576
input-output latency. Furthermore, in [2], [19], we have presented a real-time simulation for power electronics based onthis flexible programmable FPGA environment.This paper demonstrates a hardware-in-the-loop design andtesting platform for electric vehicle drive systems basedon the real-time power electronics simulation presentedin [2], [17]–[19]. We designed and implemented a real-timesimulation of an electric vehicle drive induction machineand a test bench simulation that interfaces with a deviceunder-test controller. We demonstrate the rapid prototypingcapability of the HIL platform with a variety of test cyclesand fault conditions. Lastly, we validate the fidelity of the HILsimulation by comparisons with a hardware implementation ofan electric vehicle drive.The paper is organized as follows. Section II providesan overview of the real-time power electronics simulationtechnology, and describes the modeling and computationalapproaches used to meet the hard real-time simulation requirement. Section III describes the implementation of thehardware-in-the-loop test platform for electric vehicle driveswith a two-level, three-phase voltage source inverter andinduction machine. We describe the design and implementation of the device-under-test, real-time power electronicssimulation, and test bench simulation. In Section IV, we discuss the qualitative performance of the hardware-in-the-loopplatform, and demonstrate its ability to encapsulate electricvehicle drivetrain dynamics with time constants that spanmore than five orders of magnitude. We present a prototypingdemonstration of the hardware-in-the-loop platform using theEPA Urban Dynamometer Driving Schedule (UDDS) for lightduty vehicles. Section V presents a fidelity validation of thereal-time power electronics simulation. We compare the realtime simulation with a real, small-scale electric vehicle drivesetup under various operating and fault conditions. Section VIconcludes the paper.Ad(q) eAq h heAq t · Bq dtBd(q) 0where Ad(q) and Bd(q) are the discretized state-space matrices,and h is the fixed simulation time step. Because the simulationtime step is fixed, it follows that the representation for Bd canbe formulated as follows:Bd(q) (eAq h 1) · A 1q · Bqẋ(t) Aq · x(t) Bq · u(t)(1)where x is the continuous state-space vector, u is the inputvector, and Aq and Bq are the continuous state-space matricesfor each mode q of the circuit. A mode q {q1 , ., qn }represents a given circuit configuration. The number of totalpossible circuit configurations n is constrained by n 2pwhere p is the number of switches in the circuit.We discretize the continuous state-space matrices Aq andBq for each mode using the exact discretization method, givenby:(3)Thus, the state-space vector x and output vector y can becomputed as:xk 1 Ad(q) · xk Bd(q) · uk(4)yk Cq · xk Dq · ukDuring real-time execution, a direct memory indexing technique controls the selection of the mode q based on inputs uto the system and boundary conditions defined by the outputvector y. A linear solver computes the state-space vector andoutput vector from Equation 4. An internal signal generatorand external analog and digital input ports provide the inputvector u to the state-space solver. The state-space vector xand the output vector y are accessible in real-time throughlow-latency analog output ports.The processor architecture, which is implemented in afield-programmable gate array (FPGA) device, guarantees theduration of execution for each time interval to be shorterthan the fixed simulation time step h, resulting in real-timeperformance regardless of the size of the system. Furthermore,the loop-back latency is minimized with custom designedinput-output hardware, and has been characterized to be onthe order of 1 μs.II. R EAL -T IME P OWER E LECTRONICS S IMULATIONThe approach to modeling power electronics converters usedin this hardware-in-the-loop platform is based on the work thatwe have detailed in [2], [18], [19]. We use the generalizedautomaton modeling approach, which relies on piece-wiselinear passive elements, piece-wise linear switches, and currentand voltage sources. The switched hybrid system model isgiven in the state-space form as:(2)III. I MPLEMENTATION OF HIL E LECTRIC V EHICLET ESTING P LATFORMWe demonstrate a complete HIL testing environment for anelectric vehicle by interfacing the real-time power electronicssimulation presented in Section II with a device-under-testcontroller and a real-time test bench simulation. As shown inFigure 1, the HIL testing environment is comprised of threefunctional blocks: (1) the device-under-test controller, (2) thereal-time electric vehicle drive model, and (3) the real-timetest bench simulation.A. Device-under-test controllerFor this demonstration, the device-under-test controller is ascalar volts per hertz (V/F) six-pulse space-vector modulatorwith closed-loop control of the motor shaft speed. The controller is compiled and executed on a dSpace RT1104 real-timedevice. The modulator uses a 16 kHz switching frequency with200 ns deadtime. Real-time controls, including the closed-loopspeed control, are computed at a fixed 100 μs time step.2577
&RQWURO VLJQDOV7HVW EHQFK VLPXODWLRQ3RZHU HOHFWURQLFV VLPXODWLRQ/D D QDORJ , 27UDQVPLVVLRQ9HKLFOH '\QDPLFVG\QDPRPHWHU GULYLQJ VFKHGXOHIDXOWV(QYLURQPHQW YDULDEOHV7LPH VFDOHa PVa XVFig. 2. A functional implementation of the power electronics simulation and the test bench simulation that comprise the hardware-in-the-loop platform. Thecircuit model of the electric vehicle drive power stage is shown.The goal of this implementation is to show that the deviceunder-test controller can be designed, prototyped, and testedwithout the need to interface with a high-power system. Inaddition, we will demonstrate in Section V that this controllercan be connected to a high-power two-level inverter, and theresponse of the power system will be identical to that of thereal-time simulation.B. Real-time electric vehicle drive modelThe real-time simulation of the electric vehicle drivetrainis based on the modeling and computational approaches described in Section II.We model the electric vehicle drive power stage as atwo-level, three-phase voltage source inverter connected toa squirrel cage induction machine, as shown in Figure 2. ADC source replicates the high-voltage DC bus in the electricvehicle system. The inverter is modeled using six IGBTs withantiparallel diodes. Three single-pole, single-throw (SPST)contactors are placed between each phase of the inverter andinduction machine to enable fault injection. The inductionmachine is modeled using the state-space approach. The perphase equivalent circuit parameters for this induction machinemodel are given in Table I. This model is based on theMarathon Electric 56H17T2011A, which is used in Section Vto validate the real-time simulation.TABLE IP ER PHASE INDUCTION MACHINE EQUIVALENT CIRCUIT PARAMETERS .Number of polesStator resistance (Rs )Rotor resistance (Rr )Stator leakage reactance (Xs )Rotor leakage reactance (Xr )Mutual reactance (Xm )49.25 Ω7.15 Ω9.08 Ω4.28 Ω170 ΩC. Test bench simulationThe real-time test bench is simulated on the dSpace RT1104real-time device. During real-time execution, the test benchsimulates the vehicle dynamics and generates environmentvariables for the real-time simulation, including mechanicaltorque loads on the induction machine shaft and open-phasefaults between the inverter and machine, as shown in Figure 2.The test bench enables comprehensive control of the real-timesimulation environment, providing the capability to test a widerange of operating and fault conditions.In this demonstration, the test bench performs a dynamometer driving schedule test on the electric vehicle hardwarein-the-loop platform. The test bench uses the standard EPAUrban Dynamometer Driving Schedule (UDDS) for light dutyvehicles. The UDDS is a United States Environmental Protection Agency (EPA) mandated dynamometer test on vehicleemissions and fuel economy for light duty vehicle testing.Specifically, the UDDS emulates driving conditions in urbanareas, including city and highway driving. The cycle consistsof both motoring and braking conditions. The average loadfactor of the UDDS is approximately 20 to 25 percent of themotor rated power. The UDDS is used as part of a numberof vehicle test procedures, including the U.S. FTP-72 (FederalTest Procedure) cycle, LA-4 cycle, in Sweden as A10 or CVS(Constant Volume Sampler) cycle and in Australia as the ADR27 (Australian Design Rules) cycle [20]. Although many ofthese dynamometer drive cycles were originally designed asa benchmark for fossil fuel-based vehicles, these drive cyclescan also provide estimates on electric vehicle range and powerusage efficiency.The dynamometer driving schedule test serves as a demonstration of the prototyping capabilities of the hardware-in-theloop platform. This capability to test over a wide range ofoperating and fault conditions enables predictions about elec-2578
common mode voltage (p.u.)tric vehicle range and provides the opportunity for controlleroptimization.IV. P ERFORMANCE E VALUATION0.660.330 200 1000time (µs)100200(a) Real-time HIL simulation of the common mode voltage from the neutralpoint of the induction machine to the negative DC-link.phase current (p.u.)1.0icibia0.50 0.5 1.0 16.7 8.30time (ms)8.316.7(b) Real-time HIL simulation of phase currents of a running induction machine.shaft speed (p.u.)In this section, we discuss the qualitative performance ofthe hardware-in-the-loop platform, and demonstrate its abilityto encapsulate electric vehicle dynamics with time constantsthat span more than five orders of time magnitude, as shown inFigure 2. Figure 3 shows a demonstration of simulations andtests performed on the hardware-in-the-loop platform. Thesesimulations and tests include:1) induction machine common mode voltage simulation,2) phase current simulation, and3) an EPA Urban Dynamometer Driving Schedule (UDDS)test.Similar to a physical system, these dynamics range from themicrosecond scale, as seen in Figure 3a, to the second scaleand higher, as seen in Figure 3c.Figure 3a shows a real-time HIL simulation of the commonmode voltage between the neutral point of the inductionmachine and the negative DC-link. At this microsecond timescale, the real-time simulation, which operates at a fixed 1 μstime step, provides a clear picture of common mode voltagesthat switch on the order of 1 to 10 μs. This demonstratesthe ability of the hardware-in-the-loop platform to capturedynamics and faults that occur at this time scale. This enablesoptimization of dead time and switching frequency parametersand modulation scheme filtering for applications includingcommon-mode voltage reduction and harmonic reduction.Figure 3b shows a real-time HIL simulation of the phasecurrents of a running induction machine. This measurementdemonstrates the ability of the hardware-in-the-loop platformto capture dynamics that occur at the millisecond time scale.Section V will validate the fidelity of these dynamics from thereal-time simulation. In addition to measurable quantities, thereal-time simulation provides estimations about quantities thatare difficult to measure, such as rotor flux. These dynamics,including phase currents and motor shaft speed, can be usedfor high-performance closed-loop control estimators.Figure 3c shows a test of the EPA Urban DynamometerDriving Schedule (UDDS), which is described in Section III-C.We measure the shaft speed of the vehicle drivetrain, whilethe simulation test bench sets the speed and torque referencepoints according to the driving schedule. The dynamometerdriving schedule test demonstrates the interface between theslower dynamics of the vehicle system, such as the torqueresponse of the drive cycle, and the fast dynamics of thepower electronics drive. The hardware-in-the-loop platformencapsulates both slow and fast dynamics, which enablestesting for a wide range of operating and fault conditions.The dynamometer driving schedule tests, for instance, providevaluable information about vehicle performance, system efficiency, and battery state-of-charge. Additionally, controllersand data loggers can optimize the long-term performance andreliability of the electric vehicle drive.1.010.500200400600time (s)80010001200(c) Real-time HIL test of the EPA Urban Dynamometer Driving Schedule(UDDS).Fig. 3. A demonstration of real-time HIL simulations and tests that areattainable with the HIL platform for electric vehicles. Per unit equivalence isshown in Table II.The hardware-in-the-loop platform has demonstrated theability to model a wide range of electric vehicle drivetraindynamics. This functionality provides the ability to observefaults and fast transients, prototype closed-loop controllers,and optimize long-term performance and reliability.V. E LECTRIC V EHICLE M ODEL VALIDATIONThe fidelity of the real-time simulation is a critical priority for hardware-in-the-loop applications. In order for thehardware-in-the-loop system to be practical, the responseof the real-time simulation must be nearly identical to theresponse of the physical plant it is simulating. Additionally,the real-time simulation must maintain its fidelity at small timescales with minimal latency.In this section, we validate the fidelity of the real-time2579
2SHQ ORRS FRQWURO VLJQDOV5HDO WLPH VLPXODWLRQTABLE IIPARAMETERS FOR ELECTRIC VEHICLE DRIVE SYSTEM .2XWSXW VLJQDOV'HYLFH XQGHU WHVW '875HDO WLPH FRPSDULVRQ3K\VLFDO SODQWQuantityNumber of polesDC linkMotor rated powerFull-load (F.L.) speedF.L. torqueNominal voltage (per phase)F.L. current (per phase)2XWSXW VLJQDOVFig. 4. Functional diagram of the setup used to validate the fidelity of thereal-time simulation.1.01.01.01.01.01.0Figure 5a shows the phase current of the inverter. Figure 5bshows the rotor shaft speed response of the induction machine.As the figures demonstrate, the response of the real-timesimulation is nearly identical to that of the physical plant inboth the steady-state and transient regions.phase A current (p.u.)1.0physical plantreal time simulation0.50 0.5Torque applied at t 0 1.0 200 1000time (ms)100200(a) Phase current comparison between physical plant and real-time simulation.1.21.00.8Torque applied at t 00.60.40.20A. Mechanical torque load stepA mechanical torque load step test is used to validate thefidelity of the vehicle dynamics and electric vehicle drivesimulation. This test is designed to provide a simple validationof the real-time simulation under dynamic loading conditions,p.u.4230 Vdc0.25 hp1725 rpm1.03 N·m230 Vac1.0 Awhich are common in real-world electric vehicle operationand in dynamometer driving schedule tests. In this test case,the unloaded electric vehicle drive is motored to its full-loadspeed, and the system is allowed to reach steady state. The testbench simulation synchronizes the 2 N·m torque step signalthat is sent in parallel to both the physical plant and the realtime simulation. The test bench simulation sets a referencepoint for a torque-controlled loading machine that appliesthe mechanical torque on the shaft of the electric vehicledrivetrain. The test bench simulation sends the same referencepoint as an analog input signal to the real-time simulation.motor shaft speed (p.u.)simulation by running real-time comparisons with a physicalplant under three different operating and fault conditions. Afunctional block diagram of the validation setup is shown inFigure 4. In this setup, the real-time simulator is running amodel of the physical plant (e.g. identical topology, parametervalues, etc.). A device-under-test sends open-loop control signals to both the real-time simulation and the physical plant inparallel. Various operating and fault conditions are introducedto both the real-time simulation and the physical plant. Theoutput signals from the real-time simulation and the measuredvalues from the physical plant are compared in real-time.For this validation, the physical plant is a real, smallscale electric vehicle drive system. The electric vehicle driveconsists of a 6 kW DC power supply, which is connectedto a two-level, three-phase voltage source inverter driving athree-phase induction machine. The induction machine is aMarathon Electric 56H17T2011A model that is described inSection III. We take voltage, current, and speed measurementsfrom this physical plant to serve as a reference for the real-timesimulation. Table II presents the parameters for this electricvehicle drive system.The device-under-test is an open-loop scalar volts per hertz(V/F) inverter controller running on a dSpace RT1104 realtime device. A signal breakout board routes these controlsignals to both the real-time simulation and the physical plant.We validate the fidelity of the real-time simulation in threedifferent operating and fault conditions:1) a mechanical torque load step on the motor shaft,2) a gate drive signal loss fault, and3) an open-phase inverter fault.The test cases demonstrate the fidelity of the real-timesimulation at a variety of time scales, including both slowervehicle dynamics, shown with motor shaft speed comparisons,and faster power electronics dynamics, shown with voltageand current comparisons. The comparisons between the realtime simulation and the physical plant demonstrate that thereal-time simulation provides high-fidelity modeling for thehardware-in-the-loop platform.Valuephysical plantreal time simulation 0.6 0.4 0.20time (s)0.20.40.6(b) Motor shaft speed comparison between physical plant and real-timesimulation.Fig. 5. Validation of mechanical torque load step test case. 2 N·m torquestep applied to the motor shaft at t 0.2580
1phase current (p.u.)line to line voltage (p.u.)1.0physical plantreal time simulation0 10 0.5 80 400time (ms)4080120 1.0120phase current (p.u.)physical plantreal time simulation1 0.0167 0.00830time (s)0.0083o0.0167(a) Phase current comparison during normal operation.1.0line to line voltage (p.u.)a0.5(a) Line-to-line voltage comparison between physical plant and real-timesimulation.0physical plantreal time simulationibia0.50 0.5180 o 1Gate drive stop at t 0 20 100time (ms)10 1.00.750.50.2523time (s)0.00830.0167Fig. 7.Validation of open-phase fault test case.C. Open-phase faultGate drive stop at t 010time (s)phases of the inverter. The comparison shown in Figure 6bdemonstrates that the real-time simulation maintains goodfidelity during transient conditions at small time scales. Figure 6c shows the rotor shaft speed response of the vehicledrivetrain.physical plantreal time simulation0 0.0083(b) Phase current comparison during open-phase fault condition.10 0.016720(b) Expanded view of Fig. 6a (line-to-line voltage comparison between physicalplant and real-time simulation).motor shaft speed (p.u.)iGate drive stop at t 0 120 0.25 1ibphysical plantreal time simulation4567(c) Motor shaft speed comparison between physical plant and real-timesimulation.Fig. 6. Validation of gate drive signal loss fault mode. Gate drive signalsare stopped at t 0.B. Gate drive signal lossThe gate drive signal loss fault mode validates the real-timesimulation when the gate drive signals to the running IGBTinverter are abruptly switched to zero. The fault conditionemulates a total loss of gate drive signals to the inverter.In this condition, the IGBTs of the inverter do not conduct,but current continues to flow through the anti-parallel diodesacross the IGBTs. Additionally, the rotating motor generatesa back-EMF as the shaft speed decays. In this test case, theunloaded electric vehicle drive is motored to 75 percent ofits full-load speed, and the system is allowed to reach steadystate. The gate drive signals are set to zero, and we measurethe response of the system.Figures 6a shows the line-to-line voltage between twoAn open-phase fault test case validates the fidelity ofthe real-time simulation in a fault condition. This test caseintroduces an open-phase fault between one phase of theinverter and the induction machine. In the physical system,the electrical connection between one phase of the inverter andthe induction machine is opened. In the real-time simulation,the open-phase fault is modeled as a single-pole, single-throw(SPST) contactor, as shown in Figure 2. In this test case, thedevice-under-test controller provides a modulation frequencyof 60 Hz. We compare the phase current response of thephysical system and the real-time simulation in the normaloperating condition. Then, we introduce the open-phase faultto both the physical system and real-time simulation, and wecompare the response.Figure 7a shows the normal operating condition. Figure 7bshows the open-phase fault condition, in which the openphase fault has been introduced to phase C. The juxtapositionof these normal and fault modes clearly show the amplitudereduction and phase change of the current waveforms causedby the open-phase fault. The figures demonstrate that the realtime simulation closes matches the physical system in bothcases. Additionally, this test case validates the modeling of theinverter with zero current flowing through one of the phases.2581
VI. C ONCLUSIONSThis paper has demonstrated the design, implementation,and validation of a hardware-in-the-loop (HIL) platform forelectric vehicle drive applications. The HIL platform teststhe EPA Urban Dynamometer Driving Schedule (UDDS) onan electric vehicle drive real-time simulation. The fidelity ofthe real-time simulation is validated by means of real-timecomparisons with a real, small-scale electric vehicle drivesystem under three different operating and fault conditions.We demonstrate the fidelity and prototyping capability of thehardware-in-the-loop platform when used for electric vehicledrive testing applications.R EFERENCES[1] D. Maclay, “Simulation gets into the loop,” IEE Review, vol. 43, no. 3,pp. 109–112, 1997.[2] M. Kinsy, D. Majstorovic, P. Haessig, J. Poon, N. Celanovic,I. Celanovic, and S. Devadas, “High-speed real-time digital emulationfor hardware-in-the-loop testing of power electronics: A new paradigmin the field of electronic design automation (EDA) for power electronicssystems,” in Power Electronics/Intelligent Motion/Power Quality Conference, 2011.[3] D. Westermann and M. Kratz, “A real-time development platform forthe next generation of power system control functions,” vol. 57, no. 4,pp. 1159–1166, 2010.[4] C. Dufour, V. Lapointe, J. Belanger, and S. Abourida, “Hardware-in-theloop closed-loop experiments with an FPGA-based permanent magnetsynchronous motor drive system and a rapidly prototyped controller,” inProc. IEEE Int. Symp. Industrial Electronics ISIE 2008, pp. 2152–2158,2008.[5] S. Abourida and J. Belanger, “Real-time platform for the control,prototyping, and simulation of power electronics and motor drives,”in Proc. 3rd International Conferene on Mondeling, Simulation, andApplied Optimization, 2009.[6] C. Bordas, C. Dufour, and O. Rudloff, “A 3-level neutral-clampedinverter model with natural switching mode support for the real-timesimulation of variable speed drives,” in Planet-RT Opal White Paper,2009.[7] C. Dufour, G. Dumur, J.-N. Paquin, and J. Belanger, “A PC-basedhardware-in-the-loop simulator for the integration testing of moderntrain and ship propulsion systems,” in Proc. IEEE Power ElectronicsSpecialists Conf. PESC 2008, pp. 444–449, 2008.[8] J. Langston, L. Qi, M. Steurer, M. Sloderbeck, Y. Liu, Z. Xi, S. Mundkur,Z. Liang, A. Q. Huang, S. Bhattacharya, W. Litzenberger, L. Anderson,P. Sosrensen, and A. Sundaram, “Testing of a controller for an ETObased STATCOM through controller hardware-in-the-loop simulation,”in Proc. IEEE Power & Energy Society General Meeting PES ’09, pp. 1–8, 2009.[9] Y. Liu, Z. Xi, Z. Liang, W. Song, S. Bhattacharya, A. Huang,J. Langston, M. Steurer, W. Litzenberger, L. Anderson, R. Adapa,and A. Sundaram, “Controller hardware-in-the-loop validation for a 10MVA ETO-based STATCOM for wind farm application,” in Proc. IEEEEnergy Conversion Congress and Exposition ECCE 2009, pp. 1398–1403, 2009.[10] C. Graf, J. Maas, T. Schulte, and J. Weise-Emden, “Real-time HILsimulation of power electronics,” in Proc. 34th Annual Conf. of IEEEIndustrial Electronics IECON 2008, pp. 2829–2834, 2008.[11] J. Wu, C. Dufour, and L. Sun, “Hardware-in-the-loop testing of hybridvehicle motor drives at Ford Motor Company,” in Proc. IEEE VehiclePower and Propulsion Conf. (VPPC), pp. 1–5, 2010.[12] M. Harakawa, C. Dufour, S. Nishimura, and T. Nagano, “Real-timesimulation of a PMSM drive in faulty modes with validation against anactual drive system,” in Proc. 13th European Conf. Power Electronicsand Applications EPE ’09, pp. 1–9, 2009.[13] A.-L. Allegre, A. Bouscayrol, J.-N. Verhille, P. Delarue, E. Chattot, andS. El-Fassi, “Reduced-scale-power hardware-in-the-loop simulation ofan innovative subway,” vol. 57, no. 4, pp. 1175–1185, 2010.[14] J. G. Kassakian, “Simulating power electronic systems—a new approach,” vol. 67, no. 10, pp. 1428–1439, 1979.
vector y. A linear solver computes the state-space vector and output vector from Equation 4. An internal signal generator and external analog and digital input ports provide the input vector u to the state-space solver. The state-space vector x and the output vector y are accessible in real-time through low-latency analog output ports.
May 02, 2018 · D. Program Evaluation ͟The organization has provided a description of the framework for how each program will be evaluated. The framework should include all the elements below: ͟The evaluation methods are cost-effective for the organization ͟Quantitative and qualitative data is being collected (at Basics tier, data collection must have begun)
Silat is a combative art of self-defense and survival rooted from Matay archipelago. It was traced at thé early of Langkasuka Kingdom (2nd century CE) till thé reign of Melaka (Malaysia) Sultanate era (13th century). Silat has now evolved to become part of social culture and tradition with thé appearance of a fine physical and spiritual .
On an exceptional basis, Member States may request UNESCO to provide thé candidates with access to thé platform so they can complète thé form by themselves. Thèse requests must be addressed to esd rize unesco. or by 15 A ril 2021 UNESCO will provide thé nomineewith accessto thé platform via their émail address.
̶The leading indicator of employee engagement is based on the quality of the relationship between employee and supervisor Empower your managers! ̶Help them understand the impact on the organization ̶Share important changes, plan options, tasks, and deadlines ̶Provide key messages and talking points ̶Prepare them to answer employee questions
Dr. Sunita Bharatwal** Dr. Pawan Garga*** Abstract Customer satisfaction is derived from thè functionalities and values, a product or Service can provide. The current study aims to segregate thè dimensions of ordine Service quality and gather insights on its impact on web shopping. The trends of purchases have
Chính Văn.- Còn đức Thế tôn thì tuệ giác cực kỳ trong sạch 8: hiện hành bất nhị 9, đạt đến vô tướng 10, đứng vào chỗ đứng của các đức Thế tôn 11, thể hiện tính bình đẳng của các Ngài, đến chỗ không còn chướng ngại 12, giáo pháp không thể khuynh đảo, tâm thức không bị cản trở, cái được
power system: the automatic load frequency control loop (ALFC) and the automatic voltage control loop (AVR). There is little interaction from the ALFC loop to the AVR loop but the AVR loop does affect the ALFC loop to a certain extent. The AVR loop tends to be much faster than the ALFC loop with time constants of much less than one second.
the opinions of those with direct ties to the West Loop. I live in the West Loop I work in the West Loop I own property in the West Loop I own a business in the West Loop I am generally interested in the West Loop* Other (please specify) * 0 20 40 60 80 100 23.6% 59.7% 5.6% 4.9% 85.4% 32.6% 18 West Loop Design Guidelines Community Feedback 1 .
