Abstract:
A fuel cell system is disclosed, which includes a fuel cell stack coupled to a load for providing power, a gas delivery system coupled to the fuel cell stack for providing fuel and oxygen to the fuel cell stack and a control system. The control system includes a forward controller for generating a desired control instruction signal based on a command from the load, and a correction controller for generating a control correction signal to avoid violating operational constraints of the fuel cell stack based on at least one measured signal from the fuel cell system. The control system generates a control signal based on the desired control instruction signal and the control correction signal, and controls the gas delivery system based on the generated control signal to ensure the fuel cell stack is operated within safe operating limits. A method for controlling the fuel cell system is also disclosed.
Abstract:
A system (100, 200) is presented. The system includes a fluid lifting device (102, 202) located inside a well (106, 206), and comprising an electrical motor (108, 208), a three phase cable (114, 214) for coupling the fluid lifting device to a power source (112, 212), at least one high sensitivity differential current transformer (104, 203, 204) for generating imbalance signals (128, 227) representative of an imbalance current in at least one of the electrical motor and the three phase cable, wherein the at least one high sensitivity differential current transformer is disposed such that the at least one high sensitivity differential current transformer surrounds at least a portion of the three phase cable, and a processing subsystem (136, 236) for monitoring the health of at least one of the fluid lifting device and the three phase cable based on the imbalance signals.
Abstract:
Systems and methods are disclosed for on-line monitoring of the condition of the stator insulation of an AC motor or an electric generator. In certain embodiments, the system includes a transformer surrounding each pair of input and output cables associated with a given phase of power provided to the AC motor or generated by the electric generator. In another embodiment, a transformer surrounds the three input cables (for an AC motor) or the three output cables (for an electric generator) that correspond to phases of the AC motor or electric generator. In both embodiments, the transformers generate voltages that may be used to monitor leakage currents associated with the cables. A microcontroller monitors the voltages generated by the transformers and determines the condition of the stator insulation of the AC motor or the electric generator based on the voltages.
Abstract:
A current transformer is provided. The current transformer comprises an inner magnetic core having a central opening, an outer sense core circumscribing the inner magnetic core, at least one pair of conductors extending through the central opening and positioned symmetrically with respect to a center point of the inner magnetic core, and one or more coils disposed on the inner magnetic core, the outer sense core, or both, in a magnetically balanced configuration relative to a magnetic neutral axis of the inner magnetic core.
Abstract:
A current transformer is provided. The current transformer comprises an inner magnetic core having a central opening, an outer sense core circumscribing the inner magnetic core, at least one pair of conductors extending through the central opening and positioned symmetrically with respect to a center point of the inner magnetic core, and one or more coils disposed on the inner magnetic core, the outer sense core, or both, in a magnetically balanced configuration relative to a magnetic neutral axis of the inner magnetic core
Abstract:
Systems and methods are disclosed for on-line monitoring of the condition of the stator insulation of an AC motor or an electric generator. In certain embodiments, the system includes a transformer surrounding each pair of input and output cables associated with a given phase of power provided to the AC motor or generated by the electric generator. In another embodiment, a transformer surrounds the three input cables (for an AC motor) or the three output cables (for an electric generator) that correspond to phases of the AC motor or electric generator. In both embodiments, the transformers generate voltages that may be used to monitor leakage currents associated with the cables. A microcontroller monitors the voltages generated by the transformers and determines the condition of the stator insulation of the AC motor or the electric generator based on the voltages.