Developing Power Hardware-in-the-Loop Based Testing Environment for Volt-Var and Frequency-Watt Functions of 500 kW Photovoltaic Smart Inverter. - Hiroshi Kikusato; Taha Selim Ustun; Jun Hashimoto; Kenji Otani; Takayuki Nagakura; Yasutoshi Yoshioka; Ryo Maeda; Kenjiro Mori (IEEE Access, 2020)