In hybrid grid-integrated system with grid-following and grid-forming (GFL-GFM) converters

the coexistence of multiple control strategies and frequent control mode switching leads to the complex voltage response characteristics

making it challenging to rapidly and accurately assess transient voltage stability. To address these issues

this paper proposes a transient voltage stability assessment method for GFL-GFM hybrid grid-integrated system based on the maximum Lyapunov exponent of switching system (SSMLE). First

the voltage trajectory variational equations under different operating conditions of the hybrid grid-connected system are established

taking into account the influence of multiple operating states and system parameters on transient voltage response characteristics. Then

the SSMLE is computed by segmentally solving the variational equations within each operating state. To enhance the speed and accuracy of voltage stability assessment

a switching compensation matrix is introduced to correct deviations in the integral terminal matrix at control switching instants. Subsequently

the SSMLE is used to analyze the influence of key system parameters on transient voltage stability and to determine the corresponding parameter region for stability. This provides a reference for system operators to assess operating conditions and update voltage stability control strategies. Finally

the proposed method is validated through simulations on a hybrid grid-integrated system with GFL-GFM converters and a multi-machine hardware-in-the-loop simulation platform.