This paper evaluates negative-sequence voltage control for grid-forming converters under asymmetrical faults. Six control methods based on vector voltage control with virtual impedance and virtual admittance control are compared in terms of control objectives, small-signal stability, and parameter tuning complexity. It is found that the direct implementation of virtual impedance or virtual admittance may cause small-signal instability due to insufficient damping. Stable operation can be achieved by introducing an LPF, modifying the virtual-impedance feedback structure, or adding virtual resistance with an HPF. Among the evaluated methods, virtual admittance control with proper damping provides stable operation with lower parameter tuning complexity and is identified as the optimal control solution for negative-sequence voltage control.