Power systems undergoing large-scale renewable deployment require accurate dynamic models of inverter-based technologies such as solar photovoltaic plants, wind turbine generators, and battery energy storage systems to perform the require studies that would allow to assess and maintain power grid stability. The second generation of the Western Electricity Coordinating Council (WECC) generic renewable energy system (RES) models provides a general framework for modeling inverter-based resources in power system dynamics and stability studies. In this paper, we expand the existing Modelica-compliant open-source OpenIPSL.Electrical.Renewables package by implementing the Renewable Energy Generator/Converter B (REGC_B) model along with the Renewable Energy Electrical Controller (REEC\D) model, according to the second-generation WECC RES framework. Using Modelica's object-oriented features, the implementation emphasizes modularity and reusability in building scalable power system models using the OpenIPSL library. This work highlights the potential of using Modelica and OpenIPSL to support a standardized, scalable development of inverter-based RES models within the WECC framework, and extents the only fully Modelica-compliant open-source package that implements these models.