In this study, a newly developed amalgam power flow controller (APFC) is used for better controllability and voltage stability enhancement of modern power system with deep renewable penetration. A new voltage stability index is proposed to determine the potential site of APFC and then Grey Wolf optimisation based on fuzzy logic is adopted to determine the optimal parameter settings of the APFC. A quarter cosine and exponential fuzzy membership function have been used to find out membership value of diverse objectives. The multi-objective problem is formulated considering three different objectives of conflicting nature. The proposed optimisation framework is implemented on an IEEE benchmark system of 30 buses for different cases. The comparison of simulation results reveals the effectiveness of the proposed model.