Hardware-In-the-Loop Platform at Clean Energy Research Laboratory

The Company

Nanyang Technological University (NTU) in Singapore is a world-renowned autonomous research university, ranked 11th globally and 1st in Asia in the 2018 QS World University Rankings. Located within NTU’s School of Electrical and Electronic Engineering (EEE), the Clean Energy Research Laboratory (CERL) focuses on the R&D of energy management techniques, energy storage strategies, and power converter controls for smart grids and microgrids.

The Challenges

• High Cost & Time of Physical Setups: Building full physical hardware setups for large multi-microgrid systems—containing renewable energy sources, storage devices, and power converters—is extremely tedious, time-consuming, and costly for time-sensitive projects.
• Sub-Microsecond Simulation Precision: Real-time HIL testing of electrical motor controls and fast converter dynamics requires simulation sampling below one microsecond to achieve low communication latency that closely mimics reality.
• Multi-Project Concurrent Execution: CERL hosts numerous Postgraduate (PhD, MEng, MSc), Final Year Projects (FYP), and Design & Innovation Projects (DIP) annually, requiring a highly reconfigurable setup capable of supporting multiple research teams simultaneously.
• Complex Transactive Energy Validation: Testing novel regulation strategies, such as the 3.5-year EMA-funded “Novel Hierarchical Transactive Energy Management System (HTEMS)” project, demands seamless integration between simulated grid networks and physical hardware controllers.

The OPAL-RT Solution

With funding provided by Singapore’s Energy Market Authority (EMA) and National Research Foundation (NRF CREATE), CERL established a versatile HIL and PHIL testing infrastructure:

• OP5600 & OP5607 Real-Time Simulators: Deployed high-performance OPAL-RT digital simulators to run real-time dynamic models of complex AC/DC microgrids and distribution networks.
• Integrated HIL Platform: Combined OPAL-RT digital simulations with physical hardware devices, drastically reducing setup time and enabling safe, rapid controller prototyping.
• 45kVA Power-HIL (PHIL) Expansion: Integrated a 45kVA three-phase power amplifier to connect real-time digital simulations directly with physical equipment, including lithium-ion batteries, super-capacitors, programmable power sources, and loads.
• Reconfigurable Multi-User Architecture: Designed a flexible environment where multiple student and postgraduate research projects can be implemented on OPAL-RT simulators concurrently.

The Results

• HTEMS Project Delivery: Successfully executed HIL experiments on hybrid AC/DC microgrids, hybrid energy storage systems, and dynamic voltage restorers, fulfilling key objectives of the EMA-funded HTEMS project.
• Top-Tier Scientific Output: Produced multiple research papers published in leading international journals and conferences.
• Award-Winning Student Research: Undergraduate FYP and DIP students achieved paper acceptance at the 2018 IEEE International Conference on Innovative Smart Grid Technologies (ISGT ASIA). Additionally, DIP students won 2nd place in the competition among ten EEE Smart Grid focus groups.
• Expanded Test Capability via PHIL: Bridged the gap between simulation models and physical microgrid hardware, allowing researchers to evaluate advanced performance characteristics under realistic load and storage conditions.

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