Two-phase cooling systems, power electronics modules, and methods for extending a maximum heat flux point of a two-phase cooling device are disclosed. In one embodiment, a method of operating a two-phase cooling device having an inlet, a chamber fluidly coupled to the inlet, and a heat transfer surface configured to receive heat flux from a heat generating device includes detecting at least one two-phase process parameter of the two-phase cooling device, and controlling a temperature of a coolant fluid at the inlet such that it is a first inlet temperature Tin1 when the at least one two-phase process parameter is less than a threshold. The method further includes controlling a temperature of the coolant fluid at the inlet such that it is a second inlet temperature Tin2, where Tin2 is less than Tin1.