Abstract: A single-phase voltage source inverter including a first stage configured to be connectable to a DC source, and a second stage configured to be connectable to an AC load, the first stage including a bridge leg including first and second decoupling switches, the bridge leg connected through an inductor to a decoupling capacitor, where the decoupling capacitor is in series with the DC source when the inverter is connected to the DC source, and the second stage including a bi-directional H-bridge inverter including first, second, third and fourth switches. The decoupling capacitor can be a small film capacitor. The first and second decoupling switches are the only decoupling switches in the bridge leg. The first controller can use pulse width modulation and the second controller uses sinusoidal pulse width modulation. The first controller can use pulse width modulation and the second controller uses pulse energy modulation.

Abstract: An axial flow turbine for generating electricity in low-head environments comprises a runner supported by guide vanes that are curved or contoured to direct flowing water onto fixed turbine blades. The axial flow turbine has a housing that provides an outer draft tube. A second inner draft tube is supported within the outer draft. The axial flow turbine may have a bulb or pit-type housing at the intake chamber for housing a direct-drive variable-speed permanent magnet synchronous generator (PMSG) and power converter system. The axial flow turbine may be installed as a single modular unit in low head environments.

Abstract: An axial flow turbine for generating electricity in low-head environments comprises a runner supported by guide vanes that are curved or contoured to direct flowing water onto fixed turbine blades. The axial flow turbine has a housing that provides an outer draft tube. A second inner draft tube is supported within the outer draft. The axial flow turbine may have a bulb or pit-type housing at the intake chamber for housing a direct-drive variable-speed permanent magnet synchronous generator (PMSG) and power converter system The axial flow turbine may be installed as a single modular unit in low head environments.

Abstract: This invention provides a wind turbine-battery-dump load stand-alone renewable energy system and an optimal control of the same. The system may include both power conversion and control units. In one embodiment, the power conversion unit features a wind-turbine-driven three-phase induction generator, a diode rectifier, a battery charger, a boost dc/dc converter, a battery bank (48V), and a dc/ac inverter. A dump load is also used to dissipate excess power that is not required for either the battery charging or for the load. The integrated control unit may use the TMS320LF2407A DSP microcontroller from Texas Instruments, which allows operations of the wind power system and the battery storage system to be merged into a single package under a master controller. An embodiment of the control system features battery-charging control, battery voltage-boost control, dump load control, PWM inverter control, and system protection.

Abstract: A power conversion apparatus and method suitable for use with a variable speed two-phase generator are disclosed herein. A rectifier module is adapted to receive varying electrical power from a generator and produce a direct current link voltage with a controlled magnitude at a direct current link; and an inverter module is adapted to receive the direct current link voltage from the rectifier module via the direct current link and produce an alternating current voltage; the rectifier module comprises symmetrical circuit topologies thereby eliminating vibration and noise which may come from the generator. One rectifier module disclosed includes a circuit which is substantially of the class of circuits having two or more diodes operating in combination wherein one or more diodes have been replaced with one or more switching devices, rendering the rectifier controllable by Pulse Width Modulation.

Abstract: An improved Single-Stage Buck-Boost inverter (S2B2 Inverter) is provided, using only three or four power semiconductor switches and two coupled inductors in a flyback arrangement. The inverter can handle a wide range of dc input voltages and produce a fixed ac output voltage. The inverter is well suited to distributed power generation systems such as photovoltaic and wind power and fuel cells, for standalone or grid connected applications. The inverter has a single charge loop, a positive discharge loop and a negative discharge loop.

Abstract: This invention provides a wind turbine-battery-dump load stand-alone renewable energy system and an optimal control of the same. The system may include both power conversion and control units. In one embodiment, the power conversion unit features a wind-turbine-driven three-phase induction generator, a diode rectifier, a battery charger, a boost dc/dc converter, a battery bank (48V), and a dc/ac inverter. A dump load is also used to dissipate excess power that is not required for either the battery charging or for the load. The integrated control unit may use the TMS320LF2407A DSP microcontroller from Texas Instruments, which allows operations of the wind power system and the battery storage system to be merged into a single package under a master controller. An embodiment of the control system features battery-charging control, battery voltage-boost control, dump load control, PWM inverter control, and system protection.

Abstract: A method of system for three-phase voltage detection wherein the magnitude of a grid voltage is calculated using a grid voltage vector derived from the grid voltage using Park Transformation and then compared to a predetermined voltage threshold is disclosed.

Abstract: An improved Single-Stage Buck-Boost inverter (S2B2 Inverter) is provided, using only three or four power semiconductor switches and two coupled inductors in a flyback arrangement. The inverter can handle a wide range of dc input voltages and produce a fixed ac output voltage. The inverter is well suited to distributed power generation systems such as photovoltaic and wind power and fuel cells, for standalone or grid connected applications. The inverter has a single charge loop, a positive discharge loop and a negative discharge loop.