The case study featured here is a 3 MW doubly fed induction motor (DFIM) drive used for mining applications. The DFIM drive controls were designed, built, and tested by Indrivetec AG, at the request of CSE-Uniserve. Indrivetec AG is a Zurich-based power electronics, drives, and energy storage company and is an early adopter of Hardware-in-the-Loop (HIL) technology with a research lab primarily based on HIL for control design and testing.
The stator of this motor is connected to the medium voltage grid, and the rotor is connected to a liquid resistor of the system integrator CSE-Uniserve and an Indrivetec Insulated-gate bipolar transistor (IGBT) converter. Here, the resistor is used for starting and running at a constant speed, while the converter is used for variable speed operation.
Frequency regulation is currently provided by large individual resources, such as coal plants and gas turbines. There is growing interest for utilizing power flexibility of DERs in microgrids for providing frequency regulation. Researchers, funded by ARPA-E, from the University of California San Diego (UCSD) have developed a control framework for a microgrid that coordinates DERs for frequency regulation.
Using a Controller Hardware-in-the-Loop simulation platform, EPC Power was able to integrate their control software with new hardware in just two days.
Based in San Diego, CA, EPC Power designs and manufactures grid forming bi-directional inverters and DCDC converters for solar, wind, energy storage, automotive and microgrid applications.
Ryan Smith, Chief Technology Officer (CTO) and chief controls architect, talks about his experience using Controller Hardware in the Loop (C-HIL) from the early conceptual stage, to final product certification and lifecycle maintenance.
From Centralized to Distributed Microgrid
Today, most microgrids are controlled in a centralized fashion with standard master slave architecture. There is a central controller, which is the supervisory controller and is connected via point-to-point connection to every DER in the microgrid.
Researchers from the University of Illinois at Urbana Champaign (UIUC) funded by ARPA-E, have developed a completely distributed controller architecture. Instead of a central controller, multiple micro controllers or nodes communicate with its neighbors towards a consensus. Olaolu Ajala, a PhD student in power and energy systems at UIUC, shows how this distributed controller architecture works using a Hardware-in-the-Loop microgrid testbed.
Sandia National Laboratories is the largest U.S. Department of Energy national lab with over 12,000 employees. It has a major role in supporting inverter development and testing protocols for standards organizations and distributed energy research (DER) vendors.
Jay Johnson, a principal member of technical Staff at Sandia, leads several renewable energy research projects in the U.S., Europe, and Asia.
He talks about his research paper, “Design and Evaluation of SunSpec-Compliant Smart Grid Controller,” and why Controller Hardware-in-the-Loop (CHIL) is a novel approach.
At the Microgrid & DER Controller Symposium 2017, the brainchild of Erik Limpaecher from the MIT Lincoln Laboratory, the ultra-high fidelity controller Hardware in the Loop (HIL) was in the spotlight, and it was glowing. It won the hearts and minds of all power engineers present.
At the workshop center stage, the real, unadulterated industrial microgrid controllers—from Eaton, GE, SEL, and Schneider—were in action. They were directly interfaced and controlling the Microgrid Controller HIL Testbed running real-time simulation comprising 3 feeders with 24 busses, one diesel generator, one natural gas generator with combined heat an power, battery storage, PV inverter, and numerous loads.