M. Sloderbeck

A Megawatt-Scale Power Hardware-in-the-Loop Simulation Setup for Motor Drives

We report on the application of a 5-MW variable voltage source (VVS) amplifier converter for utilization in power hardware-in-the-loop (PHIL) experiments with megawatt-scale motor drives. In particular, a commercial 2.5-MW variable speed motor drive (VSD) with active front end was connected to a virtual power system using the VVS for integrating the drive with a simulated power system. An illustrative example is given, whereby a 4-MW gas turbine generator system, including various loads, is simulated and interfaced with the VSD hardware in the lab through the VVS using current feedback to the simulation. Mechanical loading is applied to the motor via an identical 2.5-MW dynamometer connected to the same shaft. This paper first describes the PHIL facility, illustrates the challenges of powering a motor drive from a controlled voltage source converter at the multimegawatt scale, and provides experimental results from dynamic simulations. While certain challenges remain with the accuracy of the interface, it is concluded that PHIL simulations at the megawatt power level are possible and may prove useful for validating models of drive systems in the future.

Interfacing Issues in Real-Time Digital Simulators

This paper deals with the current state-of-the-art in interfacing issues related to real-time digital simulators employed in the simulation of power systems and power-electronic systems. This paper provides an overview of technical challenges encountered and their solutions as the real-time digital simulators evolved. Hardware-in-the-loop interfacing for controller hardware and power apparatus hardware are also presented.

Controller and Power Hardware-In-Loop Methods for Accelerating Renewable Energy Integration

This paper describes the basic concepts behind controller hardware-in-the-loop (CHIL) and power hardware-in- the-loop (PHIL) experimental testing from a renewable energy system integration perspective. An entire power apparatus or sub-system such as a power electronics converter for a fuel cell system or a variable speed wind power generator system can be tested in a controlled laboratory environment such as the 5 MW rated hardware-in-the-Loop (HIL) test facility established at the Center for Advanced Power Systems at Florida State University.

Testing a 5 MW high-temperature superconducting propulsion motor

A prototype marine propulsion motor manufactured by American Superconductor Corporation has been tested in the advanced test facility at the Center for Advanced Power Systems at Florida State University. The rotor of this 5 MW synchronous machine is constructed of high-temperature superconducting wire; the three-phase stator is of conventional wire. Testing was conducted with a dynamometer consisting of two 2.5 MW induction motors which permitted a wide range of conventional and novel procedures to be carried out for the characterization of the HTS motor. These tests and some of their results are discussed. The HTS motor functioned satisfactorily in all tests.

Multifunctional megawatt scale medium voltage DC test bed based on modular multilevel converter (MMC) technology

The recent development of modular multilevel converters (MMC) provides new opportunities for medium voltage DC (MVDC) systems for all electric ship design and offshore wind parks. Therefore, the Center for Advanced Power Systems at Florida State University has recently commissioned a new MVDC power-hardware-in-the-loop laboratory rated at 5 MW at DC voltages between 6...24 kV. The new lab features four individual MMCs, each composed of 36 full-bridge cells, and capable of delivering 210 A at 0...6 kV. This paper describes the entire system in detail, including the advanced current and voltage control concepts along with the state of the art digital control hardware. Selected commissioning results demonstrate the performance of the system under dynamic conditions and provide comparison with simulations obtained from a corresponding controller hardware-in-the-loop setup which is also described in the paper.

Hardware-in-the-Loop Investigation of Rotor Heating in a 5 MW HTS Propulsion Motor

Of particular concern to designers of HTS machines are potential heating effects in the superconducting windings due to AC losses caused by load fluctuations encountered in real-life operating conditions. A 5 MW HTS synchronous prototype ship propulsion motor has been tested extensively under steady-state and dynamic load conditions in the advanced test facility of the Center for Advanced Power Systems at Florida State University. This paper presents results from two tests of rotor heating effects, one employing single frequency torque oscillations and the other more realistic load modeling of sea-states by means of hardware-in-the-loop (HIL) real-time simulations. Temperature results from 4 different torque oscillation tests and 12 different sea-state tests provide rotor-heating information, obtained from multiple temperature sensor data within the HTS rotor, and are compared with data obtained from steady-state runs.

Intelligent Agents Applied to Reconfiguration of Mesh Structured Power Systems

In this paper, the authors propose a multiagent system based reconfiguration methodology for mesh structured power systems. One of the important features of this multiagent architecture is that the intelligent agents in the multiagent system work in a completely decentralized manner. There is no central controller in the system. In this multiagent system, an agent can send/receive signals to/from a major electric component in the power system. Each agent only communicates with its immediate neighboring agents. A simulation platform is also introduced for validating the proposed reconfiguration methodology. In the simulation platform, the intelligent agents are implemented using Java agent development framework. The power system is implemented in a real time digital simulator. The simulation results show the proposed reconfiguration methodology is effective and promising.

Testing of a controller for an ETO-based STATCOM through controller hardware-in-the-loop simulation

The testing of a controller for a proposed 10 MVA STATCOM through hardware-in-the-loop experimentation is described in this paper. The electrical environment into which the STATCOM is to be inserted, including a significant portion of the utility network and a nearby wind farm are simulated using a large-scale digital real time electromagnetic transients simulator. The STATCOM controller is interfaced to the simulation, providing firing pulses to the simulated STATCOM and receiving feedback of system voltages and currents. Notional wind speed data is used to simulate realistic behavior of the wind farm. This paper presents preliminary results of the ongoing testing of the controller under the most realistic system conditions.

Thermo-electric co-simulation on geographically distributed real-time simulators

In this paper, we report a combined electrical and thermal simulation carried out using two real-time digital simulators located approximately 3500 km from each other. The electrical model was developed on the RTDS simulator at the Center for Advanced Power Systems, Florida State University, Tallahassee, Florida, while the thermal model was developed on an OPAL-RT simulator located in the RTX-Lab at the University of Alberta, Edmonton, Alberta. The two simulators exchange data in an asynchronous mode on the Internet utilizing the TCP/IP and UDP protocols. Before running the actual thermo-electric co-simulation, a loop-back test was designed and run to investigate the accuracy, latency, and stability of the communication link. The loop-back test revealed a maximum latency of 0.1s for transmitting a signal from one simulator to the other including all the communication and processing delays. Simulation results corroborate the fact that despite this latency, the thermo-electric co-simulation on geographically distributed real-time simulators can be performed with sufficient accuracy and stability.

Hardware-In-the-Loop Experiments with a 5 MW HTS Propulsion Motor at Florida State University's Power Test Facility

Some aspects unique to the emerging high temperature superconducting (HTS) rotating machinery technology, such as increased AC losses in the HTS winding of the rotor circuit due to low frequency load changes, requires advanced experimental methods for R&D testing and, eventually, type testing. Therefore, this paper describes a novel 5 MW rated hardware-in-the-loop (HIL) test facility established at the center for advanced power systems at Florida State University. Integrated with a state-of-the-art digital real-time simulator this facility allows for highly complex HIL experiments in order to subject devices under test to realistic, real-life operating conditions. In particular, the paper discusses experiences from the worlds first HIL test of a 5 MW HTS synchronous machine, designed and built as a prototype ship propulsion motor technology demonstrator. During sea-state tests, a sophisticated hydrodynamic simulation model - incorporating random wave height and frequency spectra, simulated ship velocity, and the actual motor speed feedback - provided real-time torque reference signals to dynamometers loading the HTS motor. Results from HIL tests are provided and discussed in addition to an outlook on additional experimental procedures which could be applied to HTS machines for better characterization and even more rigorous real-life testing.