A variable speed system for use in systems, such as, for example, wind turbines, is described. The system comprises a wound rotor induction generator, a torque controller and a proportional, integral derivative (PID) pitch controller. The torque controller controls generator torque using field oriented control, and the PID controller performs pitch regulation based on generator rotor speed.

Variable speed wind turbine generator

A variable speed wind turbine having a generator controller coupled to a power converter with active switches operable for controlling stator electrical quantities for a multiphase generator of the turbine to enable control of the torque in the wind turbine.

Variable speed wind turbine

A variable speed wind turbine is disclosed comprising a turbine rotor that drives a doubly-fed induction generator, a matrix converter which converts variable frequency output into constant frequency output, and a control unit and a protection circuit for the matrix converter. Power is circulated in the system allowing for sensorless detection of rotor position and better output ratios of power from the system.

Variable speed wind turbine having a matrix converter

A variable speed wind turbine having a passive grid side rectifier using scalar power control and dependent pitch control is disclosed. The variable speed turbine may include an electrical generator to provide power for a power grid and a power conversion system coupled to the electrical generator. The power conversion system may include at least one passive grid side rectifier. The power conversion system may provide power to the electrical generator using the passive grid side rectifier. The variable speed wind turbine may also use scalar power control to provide more precise control of electrical quantities on the power grid. The variable speed wind turbine may further use dependent pitch control to improve responsiveness of the wind turbine.

Variable speed wind turbine having a passive grid side rectifier with scalar power control and dependent pitch control

A multi-sensor system can be attached to a high voltage power line, draw power from the power line inductively, and convert the power to lower voltages and direct currents for operating cameras, sensors, a processor, and communications equipment that provide persistent intelligence, surveillance, and reconnaissance capabilities. The multi-sensor system can detect and track targets in detection regions and transmit such detection data and other data from the camera and sensors to a remote operator who can initiate response actions and send control instructions to the multi-sensor system from the remote location.

High voltage power line multi-sensor system

A control circuit for an a.c. to d.c. power converter, in which the load current of the power converter is detected and averaged, and it is added to the voltage control signal of the voltage control system which controls the converter output voltage to be constant, so that the converter control is less affected by the ripple of the load current.

Yushin Yamamoto

Papers

Power converter control circuit