Abstract: A load site voltage regulation control system. The load site receives electrical power from a utility over transmission lines. The load site also receives electrical power from a local generator unit operating with an inverter. The local generator unit and inverter are coupled to the load by an EMI filter and a transformer. Voltage at the load is controlled by adjusting the inverter voltage using an inverter voltage command. The inverter voltage command is based on load voltage, inverter voltage, EMI filter voltage, utility supplied current, and inverter current. In one embodiment, the inverter voltage is adjusted to minimize utility supplied reactive and real power and to actively dampen EMI filter voltage, with the inverter voltage command being developed though a multi-loop PPI control system.

Abstract: A floating frame controller determines a current Park vector, selects a reference frame for the current Park vector, and adjusts the reference frame until a quadrature component of a current Park vector in the adjusted reference frame is equal to a predetermined value, whereby a synchronous reference is established. The synchronous frame is used to control a power converter. The floating frame controller can drive a synchronous machine without the use of rotor position sensors.

Abstract: A power distribution system includes an active rectifier and a controller for the active rectifier. The controller extracts a positive sequence component of a Park vector representing line voltage; and uses the positive sequence component to perform synchronous frame regulation to control the active rectifier.

Abstract: A drive arrangement for a fault tolerant variable speed induction motor provides a pair of current (torque and flux) command signals. The current command signals are converted to a three-phase output with sinusoidally varying signals. The three-phase output is modified to enable the motor to operate in the event one of the motor phases is open or disconnected. The modified three-phase output is used to provide first, second and third gate logic signals which are used for driving the motor.

Abstract: Power factor control of a pulse width modulated inverter supplied permanent magnet motor is achieved by using Park Vectors for automatically adjusting a pulse width modulating signal for approximately unity power factor, thereby avoiding the heretofore required manual adjustment during operation of the motor for power factor changes in accordance with changes in EMF and motor resistance.

Abstract: A variable speed drive system for an induction motor is disclosed which utilizes power factor correction capacitors to allow an induction motor to be driven by a line-commutated inverter using variable phase angle triggering of the thyristers in the inverter to compensate for frequency-induced changes in the operating point of the system.

Abstract: A method and apparatus for converting the output of a polyphase AC machine into a DC current by capacitor assisted line commutation within the rectifying circuitry.

Abstract: A variable speed induction motor drive system operating at a leading power factor. A prescribed reactive power is coupled to the motor's rotor, to permit line commutation of an inverter supplying the motor's stator, and to permit the inverter to be supplied by a substantially constant dc link voltage.

Abstract: A variable-speed, leading power factor AC machine which may be supplied through a line-commutated inverter.

Abstract: A sealing port for a filtering device of the type disclosed and claimed in U.S. Pat. No. 3,471,017 is described. The sealing port has two separate sections in uninterrupted communication with one another for sealing purposes but thermally isolated from one another. Both sections are provided with both heating means and coolng means which are controllable to permit the performance of a process sequence wherein a stressed barrier plug (i.e., a sealing plug formed while subject to the hydrostatic pressure of a substance being filtered) is formed in the innermost section (i.e.

Abstract: A process and apparatus for filtering substances by introducing a filter band across a passageway through which the substance flows, the filter being passed through inlet and outlet ports sealed to prevent leakage therefrom for example by thermal solidification therein of the substance being filtered or any other suitable sealing substance to form sealing plugs in the ports, and the filter being advanced to locate a fresh part thereof across the passage by supporting the filter upon a reciprocable backing support, moving the backing support in a direction to advance the filter under conditions such that the filter moves with the backing support, and subsequently retracting the backing support under conditions such as to prevent movement of the filter with the backing support.