Impacts of Linear Controllers for Power Interfaces in Damping Impedance Model Based Power Hardware-in-the-Loop

Power hardware-in-the-loop (PHIL) is an attractive real-time test and validation technique for large power systems. It can be used instead of full simulation or experimental systems to reduce cost and risk, and improve testing flexibility. A key challenge is achieving a power interface with as much transparency as possible via interface algorithms, power amplifiers, and measurement and control strategies. Voltage source converters (VSCs) are a suitable amplifier option for high power applications due to their relative efficiency, but they restrict the bandwidth and update speed of the power signal reproduced for the Item-under-Test (IuT). The stability and accuracy of the PHIL system are consequently affected by these additional dynamics. This paper evaluates the stability and accuracy of a Damping Impedance Model (DIM) based PHIL system where a VSC power interface is controlled by a linear voltage controller. It will be shown that the stability and accuracy can be improved with the use of a controller, when compared to the simple open loop modulation strategy often used in PHIL applications.