Power Hardware-in-the-Loop Interface Method for Grid Forming Inverters Using a Voltage-Controlled Power Amplifier

Incorporating grid-forming inverters (GFMI) into a power hardware-in-the-loop (PHIL) setup presents critical stability challenges if the GFMI operates in isochronous mode. Attempting to use the ideal transformer method (ITM) to interface a GFMI may pose the risk of catastrophic damage to either: the GFMI, or the power amplifier. This is caused by the lack of a synchronization mechanism in some commercially available GFMI designed to operate only in isochronous mode. One possible solution is to use a power amplifier that operates in current-control mode. However, most of the power amplifiers available in the market operate only under voltage-control mode. This paper presents a novel yet simple method to convert a voltage-controlled power amplifier into a current-controlled device by using the computational capabilities of a real-time simulator to embed the current control. This way, a stable synchronization between the GFMI and the power amplifier can be achieved, and the PHIL setup stability can be maintained.