Abstract: A mechanical oscillator-based physical quantity measurement system is disclosed. The mechanical oscillator is coupled by optical signals to a source of oscillation-sustaining energy and this energy is also time-shared between oscillation sustenance and the generation of oscillation frequency-characterized optical output signals. Measurement of physical quantities including fluidic pressure, electrical current flow, physical acceleration and magnetic field strength is contemplated with the disclosed system.

Abstract: A modified inverter/converter unit electronically commutates a switched reluctance machine to provide multiple voltage levels for engine and aircraft applications. A set of power switching transistors apply an exciting current to windings in the switched reluctance machine to produce power at a first voltage level. Additional voltage levels may be provided by using the turns ratio from a plurality of transformers and the switching frequency from the power switching transistors. Alternatively, additional voltage levels may be provided by using windings of a plurality of transformers internal to the switched reluctance machine.

Abstract: A switched reluctance generator system, including a converter for coupling a dc voltage via a dc excitation bus to a switched reluctance generator and thereby providing excitation power thereto, has a separate generator bus for providing the output voltage of the switched reluctance generator. The generator bus is separate and distinct from the dc excitation bus such that the average output current generated by the switched reluctance generator is substantially independent of the generator output voltage. The switched reluctance generator system further includes switches for coupling each respective machine phase winding of the switched reluctance generator to the generator bus such that the generator provides power to the excitation bus when the switches are turned off and provides power to the generator bus when the switches are turned on.

Abstract: A switched reluctance generator system provides an ac output voltage through only one stage of power conversion. The system includes a converter for coupling a dc voltage via a dc excitation bus to a switched reluctance generator and thereby providing excitation power thereto, and further includes a separate ac generator bus for providing the ac output voltage. A bridge-type configuration of thyristor-type switching devices are used to couple power generated across each respective machine phase winding to the ac generator bus. During initiation of generating action and load faults, the thyristor-type switching devices are turned off such that the ac generator bus is effectively disconnected from the switched reluctance generator, allowing the excitation bus to be charged to a desired level. During normal generating operation, the thyristor-type switching devices are appropriately gated, increasing and decreasing current as needed, to provide the ac output voltage on the ac generator bus.

Abstract: A switched reluctance machine comprising a housing, a stator attached to the housing and a rotor mounted within the housing. The stator including teeth wound with electrical coils which are connected to form phase windings. The rotor comprising a series of laminates including teeth pressed onto a shaft. According to the present invention, at least one set of opposing phase wound stator teeth comprise permanent magnets.

Abstract: A switched reluctance generator system, including a converter for coupling a dc voltage via a dc excitation bus (or excitation nodes) to a switched reluctance generator and thereby providing excitation thereto, has a separate generator bus for providing the output voltage of the switched reluctance generator. The generator bus is separate and distinct from the dc excitation bus such that the average current generated by the switched reluctance generator is substantially independent of the generator output voltage. As a result, the switched reluctance generator is capable of resuming generating operation after occurrence of an overload, without requiring a relatively large power source to supply the overload, clear the fault (e.g., via a fuse) and re-excite the generator.

Abstract: A method and apparatus are provided for controlling the switching devices in a switched reluctance machine bridge inverter, which inverter has at least two switching devices per phase leg, during generating operation. At the start of the conduction interval for a particular machine phase, both switching devices of that phase are turned on, causing the phase current to build up. When the phase current reaches an upper hysteresis band level, both switching devices are turned off, resulting in the application of a reverse voltage across the phase winding and directing the phase current into the power source via flyback diodes. At relatively low and medium speeds, the phase current decreases until it reaches a lower hysteresis band level, at which point only one switching device is turned back on to form a freewheeling loop through that device and the corresponding flyback diode.

Abstract: A current sensor for measuring relatively high currents in a semiconductor power switching device includes a coil wound around a nonmagnetic toroidal core situated about the conductor through which the current to be measured is flowing. The voltage between the open terminals of the coil winding is proportional to the time derivative of the current flowing in the conductor passing through the toroid. This voltage is provided to an integrator which supplies the corresponding current at its output. A control circuit resets the integrator once per cycle when the current in the switching device is zero. For a bidirectional switching device, a pulse width control circuit ensures that the integrator is reset for a fixed time before the current therein reverses direction. Any accumulation of errors, due to DC and relatively low-frequency components of current, is avoided and current measurements are reliable.