Project Background
Heavy Goods Vehicles (HGVs) electrification requires the deployment of high-power charging infrastructure, such as Megawatt Charging Systems (MCS), capable of delivering charging power at the scale of 1MW. These systems are essential to rapidly charge electric HGVs within minutes, meeting the operational demands of the logistics and freight sectors.
However, the integration of MCS into the distribution network poses significant technical challenges. Due to their high instantaneous power demand and use of power electronic converters, MCS units can introduce harmonics into the grid. Power quality disturbances may lead to non-compliance with Distribution Network Operator (DNO) standards, potentially affecting the stability and performance of nearby electrical infrastructure. Therefore, it is important to test the power quality performance of Megawatt Charging Systems under realistic operating conditions before their widespread deployment. This includes assessing total harmonic distortion in accordance with relevant engineering standards and regulations (e.g., IEEE 519 and G5/5 engineering recommendation).
Project Aims: Testing Voltempo’s HyperCharger technology
In what was the first full-scale industrial trial at the University of Strathclyde’s Advanced Net Zero Innovation Centre (ANZIC), the project evaluated the performance of Voltempo’s HyperCharger under a range of load conditions applied at the DC output terminals of the megawatt charger. This involved:
Measurement and analysis of the Voltage Total Harmonic Distortion (THD) and the Current Total Harmonic Distortion at the AC input terminals.
These harmonic measurements were taken to assess the THD impact of the megawatt charger when operating under different load scenarios (e.g. emulating different numbers of electric HGVs being charged simultaneously).
To inform and compare the response of what is typically acceptable levels of harmonic distortion, IEEE Standard 519-2022 and the UK’s G5/5 engineering recommendation were used as guides when analysing the response.
PNDC’s Role: Grid Emulation and Bidirectional Load Testing
PNDC conducted performance testing of a 1MW charger, focusing on key parameters such as efficiency, voltage and current Total Harmonic Distortion. The testing demonstrated the capabilities of the University of Strathclyde’s new Advanced Net Zero Innovation Centre (ANZIC) in Inchinnan, which is equipped to handle 1MW systems at different output voltage levels. An AC grid emulator is used to supply the charger with the required input power, while a programmable bidirectional DC load was deployed to sink the DC output current from the charger. This project strengthened the position of PNDC as a national testbed for low-carbon technologies and high-power electric vehicle infrastructure; supporting the development of decarbonised transport in the UK.
Performance testing of the 1MW charger at ANZIC, ensuring it aligned with the project timelines.
Gathering and analysing the test data by connecting a Fluke 435 II Power Quality Analysers to the megawatt charger input terminals.
Preparing a detailed report summarising the test results for client review and feedback.
The testing, showcasing the unique capabilities of the University’s new innovation centre, involved the use of an EGSTON 1MW AC grid emulator and an ETPS 1.08MW Bidirectional DC Load.
Outcomes: Demonstrating Standards-Compliant Grid Compatibility
The harmonic performance evaluation of the Voltempo HyperCharger, conducted under a range of DC load conditions and AC supply voltages at the ANZIC, demonstrates that it is in line with the limits specified in relevant power quality standards.
Voltage Total Harmonic Distortion consistently remained below 8% across all test conditions, aligning with the limits prescribed by IEEE 519-2022 and the ENA G5/5 recommendation.
Current Total Harmonic Distortion at full load (1MW AC input) was measured at 3.01%, within the 5% threshold set by IEEE 519-2022 standard.
Individual voltage and current harmonics fall within the permissible ranges outlined in the IEEE 519-2022 standard.
These results demonstrate that the HyperCharger maintains low harmonic outputs under varying operational scenarios, supporting its suitability for integration into AC networks.
Impact: Accelerating Grid-Ready Megawatt Charging
PNDC’s significant role in testing Voltempo’s HyperCharger include the following:
Provided a 1MW grid emulator that replicates a wide range of grid conditions (e.g., voltage and frequency variations, harmonics), enabling comprehensive testing of the HyperCharger’s performance and compliance under real-world grid disturbances.
Offered a dynamic load emulation through using 1.08MW bidirectional programmable loads, which allow the simulation of varying load profiles such as HGV charging demand patterns.
Measured the Total Harmonic Distortion of Current (THDI) and Voltage (THDV) using power quality analysers to evaluate the megawatt charger’s impact on grid harmonics and ensure compliance with the UK’s power quality standards.
This project highlights PNDC’s expertise in enabling the grid integration of megawatt-scale EV charging systems, ensuring power quality compliance under realistic operating conditions. As the first PNDC-led initiative at the University of Strathclyde’s Advanced Net Zero Innovation Centre, the collaboration with Voltempo marks a significant step forward in advancing next-generation charging technologies essential to the decarbonisation of heavy goods vehicles and the development of high-power EV infrastructure.
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PNDC’s project team for the collaboration with Voltempo were lead R&D engineer, Dr Kyle Jennett, and R&D engineer, Dr Soumia Ayyadi.
Established in 2013, PNDC is one of the University of Strathclyde’s industry-facing innovation centres and focuses on accelerating the development and deployment of novel energy and transport solutions through multiple collaboration models and open access facility provision.
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