Abstract: An electrical generator (114) and a power electronics interface (115) for a direct-drive turbine (110). The turbine (110) may include a rotor (112) for transforming kinetic (from, e.g., wind, water, steam) into mechanical energy, the generator (114) for transforming the mechanical into electrical energy, and the power electronics interface (115) for conditioning the electrical energy for delivery to a power distribution grid (124). The interface (115) includes a three-phase single-stage boost inverter (120) for converting a lower DC voltage into a higher AC voltage, and which uses a synchronous reactance of the generator (114) as a DC-link inductance. The turbine (110) has neither the gearbox of indirect-drive designs nor the electrolytic capacitor bank of conventional direct-drive designs, while still allowing for a substantially smaller number of generator poles, resulting in reduced size, weight, complexity, and cost.

Abstract: An electrical generator (114) and a power electronics interface (115) for a direct-drive turbine (110). The turbine (110) may include a rotor (112) for transforming kinetic (from, e.g., wind, water, steam) into mechanical energy, the generator (114) for transforming the mechanical into electrical energy, and the power electronics interface (115) for conditioning the electrical energy for delivery to a power distribution grid (124). The interface (115) includes a three-phase single-stage boost inverter (120) for converting a lower DC voltage into a higher AC voltage, and which uses a synchronous reactance of the generator (114) as a DC link inductance. The turbine (110) has neither the gearbox of indirect-drive designs nor the electrolytic capacitor bank of conventional direct-drive designs, while still allowing for a substantially smaller number of generator poles, resulting in reduced size, weight, complexity, and cost.

Abstract: An integrated DC link inductor and current sensor winding having a core that includes at least two primary legs and at least one secondary leg, two direct current (DC) link windings each wound around one of the two primary legs, and a common mode current sensor winding wound around the secondary leg. Resistors coupled to the common mode current sensor winding may damp the common mode current oscillations.

Abstract: Systems and methods for detecting ground fault at the common DC bus in a high impedance ground system. A fault detection component can detect characteristics of an electrical signal including phase number (n) and fundamental frequency (H). A fast Fourier transform is performed at (n×H) and (2n×H), and the two values are compared. A healthy system (no ground fault) can display a large difference between (n×H) and (2n×H), while in an unhealthy system the difference can be minimal. A system and method of detecting variable phase number and fundamental frequency can be used in the calculation to perform the ground fault detection when these characteristics are variable.

Abstract: Systems and methods for detecting ground fault at the common DC bus in a high impedance ground system. A fault detection component can detect characteristics of an electrical signal including phase number (n) and fundamental frequency (H). A fast Fourier transform is performed at (n×H) and (2n×H), and the two values are compared. A healthy system (no ground fault) can display a large difference between (n×H) and (2n×H), while in an unhealthy system the difference can be minimal. A system and method of detecting variable phase number and fundamental frequency can be used in the calculation to perform the ground fault detection when these characteristics are variable.

Abstract: An integrated DC link inductor and current sensor winding having a core that includes at least two primary legs and at least one secondary leg, two direct current (DC) link windings each wound around one of the two primary legs, and a common mode current sensor winding wound around the secondary leg. Resistors coupled to the common mode current sensor winding may damp the common mode current oscillations.

Abstract: A method for diagnosing induction motor broken bar faults using the resultant magnetic field pendulous oscillation phenomenon is disclosed. Broken bar faults cause the resultant magnetic field of an induction motor to possess a pendulous oscillation modulating its inherent rotation at synchronous speed, and the range of this angular pendulous oscillation, referred to as the swing angle, increases with an increase in the number of broken bars. The angular pendulous oscillation is determined by calculating the space vectors derived from motor terminal voltages and currents. The variation in the angular difference between these two space vectors versus time is used to observe the resultant magnetic field's pendulous oscillation, and thus provide on-line rotor fault diagnostics.

Abstract: A method for diagnosing induction motor broken bar faults using the resultant magnetic field pendulous oscillation phenomenon is disclosed. Broken bar faults cause the resultant magnetic field of an induction motor to possess a pendulous oscillation modulating its inherent rotation at synchronous speed, and the range of this angular pendulous oscillation, referred to as the swing angle, increases with an increase in the number of broken bars. The angular pendulous oscillation is determined by calculating the space vectors derived from motor terminal voltages and currents. The variation in the angular difference between these two space vectors versus time is used to observe the resultant magnetic field's pendulous oscillation, and thus provide on-line rotor fault diagnostics.