A fail-safe control system for controlling valves in power generation systems is presented. The AC-coupled, rectified signal supplied to one valve is disabled in the event that the other valve fails. This failure is sensed, for example, through the use of power sensing circuitry configured to sense and multiply the voltage and current applied to the valve. Components such as capacitors and transformers are used exclusively such that only AC power (and not DC power) is transferred, ensuring that, in the worst case, the valves are disabled in the event of a failure.