An exemplary power system may include an electric machine with multiple sets of stator windings, each set of windings being coupled through a separate switch matrix to a common voltage bus, and each of which may be spatially arranged in full pitch around the stator such that stator flux harmonics are substantially reduced. The reduced stator flux harmonics may be associated with phase current harmonic content. In an example application, such power systems may operate in a generating mode to transfer mechanical energy to electrical energy on a DC voltage bus. In some illustrative embodiments, the power system may provide both high-power and high-speed (e.g., 1MW at 8000 rpm or above) motoring and/or generating capability suitable, for example, for on-board (e.g., marine, aviation, traction) power systems.

Electromechanical energy conversion systems

A hydroelectric turbine for the production of electricity from tidal flow forces, the turbine having a rotor with an open center such that the blades are mounted between an inner rim and outer rim, wherein retaining members and anti-friction members are provided to limit movement of the rotor relative to the housing in either axial direction, such that water flow in either direction operates the turbine, but wherein the retaining members and the anti-friction members allow the rotor to shift in either axial direction in response to water flow. The anti-friction members limiting rotor travel in the axial direction are preferably of increased thickness, such that as the anti-friction members wear down, the rotor is able to shift relative to the housing in the axial direction.

Tidal flow hydroelectric turbine

A compressor monitoring system includes current and voltage monitors, current and voltage averaging modules, a control module, and a switch. The current monitor measures a current drawn by a motor of a compressor. The current averaging module generates first and second average current values based on the current measured by the current monitor. The voltage monitor measures a utility power voltage. The voltage averaging module generates first and second average voltage values based on the voltage measured by the voltage monitor. The control module selectively generates a fault signal when a first ratio is greater than a first predetermined threshold and a second ratio is less than a second predetermined threshold. The first ratio is based on the first and second average current values. The second ratio is based on the first and second average voltage values. The switch deactivates the motor when the fault signal is generated.

Compressor protection and grid fault detection device

This disclosure relates to transient energy systems for supplying power to a load substantially instantaneously on demand. Transient energy systems may include a flywheel coupled the rotor of an induction motor generator. One embodiment of the disclosure refers to systems and methods for reducing loads on a bearing in a transient energy system. In another embodiment, the disclosure refers to an induction motor generator that is optimized for high power transient power generation, yet low power motor operation. Yet another embodiment of the disclosure refers to using a flywheel as a drag pump to cool components of a transient energy system. In yet another embodiment, a slip control scheme is discussed for regulating a DC bus. In yet a further embodiment of the disclosure a method is provided for reducing unnecessary turbine starts by making turbine start a function of the rotational velocity of a flywheel.

Transient energy systems and methods for use of the same

In accordance with certain exemplary embodiments, the present technique provides methods and apparatus for providing operating power to a complementary device to an induction device based uninterruptible power source (UPS) via a direct current (dc) bus. In one embodiment, the UPS includes a flywheel that stores kinetic energy during conventional operating conditions, e.g., external power is available. During such operating condition, the external power operates the induction device as an induction motor. However, when external power is lost, i.e., a transient operating condition, power conversion circuitry of the UPS provides ac power to the induction device such that the induction device operates above its synchronous speed and, as such, acts as an induction generator. However to improve the operating of the exemplary UPS, it includes second power conversion circuitry that converts both generated and received power to a power level that is desirable to complementary device cooperating with the induction device.

Methods and apparatus for ride-through operation of a complementary device to a transient power source

A system and method for protecting a motor drive unit from an associated motor includes a motor drive unit protection system. The motor drive unit protection system includes at least one switch configured to be connected between a motor drive unit and a plurality of motor leads of the motor driven by the motor drive unit. The motor drive unit protection system also includes a controller configured to monitor the motor drive unit or the motor to determine a fault condition indicative of the motor potentially operating as a generator. Upon determining the fault condition, the controller is configured to cause the at least one switch to connect the plurality of motor leads together to protect the motor drive unit from the motor when the motor is operating as a generator.

System and method for protecting a motor drive unit from motor back EMF under fault conditions

In accordance with certain exemplary embodiments, the present technique provides methods and apparatus for providing transient and uninterrupted power to protected loads. As one example, the present invention provides an induction device that operates as an induction motor to energize a kinetic energy storage device, such as a flywheel, during conventional operating conditions. However, in the event of a loss of primary power, the induction device, which is fed ac power at variable frequencies, begins to operate as an induction generator. For example, by varying the frequency of the input ac power such that the synchronous speed of the motor is exceeded by the rotating flywheel, the induction device acts as an induction generator and provides a transient operating power to the downstream loads until an auxiliary power source, such as a diesel generator, is brought on line.

Apparatus and method for transient and uninterruptible power

A motor having a circuit board including at least two MEMS sensors. The circuit board is mounted within a housing of the motor using the same fasteners as an encoder of the motor. Mounting the MEMS sensors to the circuit board simplifies assembly of the motor and standardizes the positioning of the MEMS sensors within the housing, while the overall motor footprint is unaffected.

Michael J. Melfi

Papers

System and method for protecting a motor drive unit from motor back EMF under fault conditions

Apparatus and method for transient and uninterruptible power

Board mounted microelectromechanic system (MEMS) sensors for motor diagnostics and analytics