The Wind-PV-thermal bundling through AC lines is connected to grid-forming MMC-HVDC system, and AC line faults can easily cause power angle instability, overcurrent in the MMC-HVDC converter station. To address the above challenges, this paper proposes an improved virtual synchronous generator control strategy that integrates active power command, adaptive virtual impedance control. This strategy dynamically adjusts the active power command value based on the degree of voltage drop, effectively improving the power angle stability during faults, Introduce a virtual impedance with positive and negative sequence decoupling, whose value is generated based on real-time current levels, limit the overcurrent to within the allowable range. Based on RTDS simulation verification, the simulation results have demonstrated the effectiveness and superiority of the fault ride through control strategy.