A method and an apparatus to analyze two measured signals that are modeled as containing desired and undesired portions such as noise, FM and AM modulation. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, a transformation is used to evaluate a ratio of the two measured signals in order to find appropriate coefficients. The measured signals are then fed into a signal scrubber which uses the coefficients to remove the unwanted portions. The signal scrubbing is performed in either the time domain or in the frequency domain. The method and apparatus are particularly advantageous to blood oximetry and pulserate measurements. In another embodiment, an estimate of the pulserate is obtained by applying a set of rules to a spectral transform of the scrubbed signal. In another embodiment, an estimate of the pulserate is obtained by transforming the scrubbed signal from a first spectral domain into a second spectral domain. The pulserate is found by identifying the largest spectral peak in the second spectral domain.

Signal processing apparatus and method

A power conversion device includes a power switching circuit that supplies AC voltages generated between switching elements operating as upper arms and switching elements operating as lower arms, and a control circuit that generates and supplies to the driver circuit signals for controlling the switching operation of the switching elements by a PWM method in a first operational region in which frequency of an AC power to be outputted is low, and that generates and supplies to the driver circuit signals for controlling the switching operation of the switching elements at timings based upon the phase of the AC power to be outputted in an operational region in which the frequency of the AC power to be outputted is higher than in the first operational region.

Power Conversion Device

A hydroelectric power generation system (20) generates electrical power for an electrical utilization system (72). A controller (42) obtains a requested output electrical power level from a hydro- turbine unit (70) by using a signal Indicative of water head (h meas) to control speed of an asynchronous rotary converter (50) coupled to the hydro-turbine unit and to control gate position of the hydro-turbine unit. The requested output electrical power level is applied from the hydro-turbine unit via the rotary converter to the electrical utilization system. In one embodiment, the controller (42B) accesses an undatable memory wherein Hydraulic Hill Chart information is stored. In another embodiment, the controller (42C) also includes a real- time automatic governor which uses a signal indicative of ac transmission frequency to the electrical utilization system to control the output electrical power level of the rotary converter.

Asynchronous conversion method and apparatus for use with variable speed turbine hydroelectric generation

An electrical rotating apparatus comprises an inverter system that outputs more than three phases. The apparatus further includes a stator comprising a plurality of slots and full span concentrated windings, with the windings being electrically coupled to the inverter system, and a rotor electromagnetically coupled to a magnetic field generated by the stator. A signal generator generates a drive waveform signal, that has a fundamental frequency, and the drive waveform signal drives the inverter system. The drive waveform signal has a pulsing frequency and is in fixed phase relation to the fundamental frequency. Additionally, the inverter system may be fed by a drive waveform signal that is fed through at least one signal delay device.

Rotating induction apparatus

A power flow controller seeks to inject a voltage V ser on a transmission path between a first electrical area and a second electrical area, in order to cause a desired power flow into the second electrical area. The power flow controller (20) includes a series transformer (40), a regulating transformer (44), a rotary phase shifting transformer network (44), and a control system (46). The rotary phase shifting transformer network (44) includes a first rotary phase shifting transformer (102 1 ) and a second rotary phase shifting transformer (102 2 ). The first rotary phase shifting transformer and the second rotary phase shifting transformer have first terminals (windings of one of either rotors or stators) connected in parallel to a regulating winding 62) of the regulation transformer. Second terminals (windings of the other of rotors or stators) are connected in series with an excited winding (52) of the series transformer. The control system applies control signals to the first rotary phase shifting transformer and the second rotary phase shifting transformer to obtain desired phase angles θ E1 , θ E2 between the rotor (110) and stator (112) of each transformer, and thereby achieve an effective phase shift θ PFC and a voltage magnitude ratio T PFC between the first electrical area and the second electrical area.

Power flow control with rotary transformers

An electric power converter operable by means of a rotating or moving magnetic field having a substantially constant flux density or of a substantially constant magnitude. The electric power converter functions as a AC to DC, DC to AC or DC converter, or as a phase changer/phase shifter or a voltage adjuster. A feature of the converter is the continuous supply of power from the primary phases in contrast to prior art converters in which only the phase having the highest voltage supplies power at any one time. Harmonic current distortion is, therefore, substantially reduced.

John Wharton Luce

Papers

Moving magnetic field electric power converter