With the rapid development of renewable energy, power system inertia is gradually decreasing, threatening the stability of system frequency. Grid-forming (GF)-based wind turbines (WTs) equipped with active inertia response are key to addressing the problem of low-inertia power systems. However, existing researches have focused on the inertia response of GF-based WTs in the maximum power point tracking (MPPT) range, while lacking the discussion on the control and implementation of inertia response in other operating ranges. Therefore, this paper proposes an inertia response control method for permanent magnet synchronous generator (PMSG)-based WTs across the full wind speed range based on inertia synchronization control (IsynC). By analyzing the characteristics of the inertia response and safe operating boundaries of the WT at different operational stages, a control method for the smooth speed transition of the WT across different operating ranges is proposed. By utilizing a composite judgment logic based on the DC voltage rate of change and rotor speed, an adaptive inertia response for different operating modes is achieved. Single and multiple PMSG-WT simulation models are built in PSCAD/EMTDC to simulate the proposed full wind speed range inertia response control and its operational characteristics. The results demonstrate that this method enables the selective inertia response of WTs across the full wind speed range, effectively enhancing the frequency support capabilities of renewable energy generation systems.