Abstract: An energy conversion generation system receives energy from a resource and converts the energy into electrical power for supply to a polyphase electric power grid operating at a system frequency. A prime mover driven by the resource energy and a converter, such as a power electronic converter, for produces excitation power from power received from a converter power source. A brushless doubly-fed generator has a rotor with rotor windings and a stator with stator windings comprising first and second polyphase stator systems. The rotor is driven by the prime mover. The first stator system supplies the electrical power to the grid, and the second stator system receives the excitation power from the converter. A sensor senses a parameter of the electrical power output supplied to the grid and produces a sensor signal corresponding to the sensed parameter. A controller controls the converter in response to the sensor signal. The controller establiThis invention was made with government support under Grant No.

Abstract: A variable speed hydro-power plant includes a pump turbine (2) having a S-shaped characteristics at the turbine operation. A current time turbine operating point is grasped on a turbine characteristics diagram of the pump turbine (2). A limit operation characteristics curve (nr) of the pump turbine (2) is formed in advance so as to not reach the S-shaped characteristics turbine operation region. A reach of the limit operation characteristics curve (nr) is detected, a rotating speed (N) of the pump turbine (2) is lowered. An inrush of the pump turbine (2) into the S-shaped characteristics turbine operation region is eliminated, so the continuation of a stable and reliable turbine operation can be guaranteed.

Abstract: A floor position sensor monitors the movement of an elevator car and provides a first predetermined number of inputs each corresponding to a predetermined floor and connected to a first signal converting circuit providing a second predetermined number of coded outputs less than the first predetermined number in response to an input position signal appearing at one of the first inputs corresponding to the floor where the elevator car is located. Each position indicator is remotely located from the sensor and includes opto-isolating circuits connected to receive the second outputs and provides a third predetermined number of outputs photo-electrically isolated from and in response to the second outputs and connected to a second signal converting circuit providing a fourth predetermined number of coded outputs responsive to the third outputs.