Abstract: An electrical starter-generator system includes a first starter-generator and a second starter-generator. A single drive controls both the first starter-generator and the second starter-generator such that their electrical current and power inputs are minimized and balanced.

Abstract: An electrical starter-generator system includes a first starter-generator and a second starter-generator. A single drive controls both the first starter-generator and the second starter-generator such that their electrical current and power inputs are minimized and balanced.

Abstract: An electrical starter-generator system includes a first starter-generator and a second starter-generator. A single drive controls both the first starter-generator and the second starter-generator such that their electrical current and power inputs are minimized and balanced.

Abstract: An auto-transformer rectifier unit includes circuitry for eliminating DC ground faults. Generally, a capacitor is added in series between each of the input AC feeder lines. Consequently a fault on a DC rail to ground or a faulted diode will prevent or eliminate a DC current ground fault condition entirely. It will, however, retain a significant (detectable) increase in current for differential faults, which would let the protective device trip the unit off line. Large magnitude fault currents are also eliminated.

Abstract: An unbalanced current detection circuit determines when a multi-phase, normally-balanced load is unbalanced. The detection circuit of the present invention includes a plurality of current-squaring circuits, each squaring a sensed current of one of the phases. A summing circuit produces a sum of the squares of the currents. If the load is balanced, this sum should be relatively constant, perhaps changing only slowly over time, with little or no ripple from that relatively constant value. In an unbalanced current condition, the sum of the current squares would consist of an average (dc) component plus a ripple (ac) component. If the amplitude of the ripple current exceeds a threshold, it is determined that the currents are unbalanced.

Abstract: An open diode detection circuit for use with an auto-transformer rectifier unit includes a plurality of first diodes each connecting one of a plurality of transformer nodes to a detector rail. A comparator compares the detector rail to a rectifier rail, which is also connected by a plurality of diodes to the plurality of transformer nodes. If one of the diodes in the rectifier circuit fails, the voltage on the rail in the rectifier circuit will differ from the voltage on the rail in the detection circuit. This difference will exceed a threshold that is detected by a comparator, which then generates an indication that a diode has failed.

Abstract: An electrical starter-generator system includes a first starter-generator and a second starter-generator. A single drive controls both the first starter-generator and the second starter-generator such that their electrical current and power inputs are minimized and balanced.

Abstract: An improved motor controller for driving polyphase alternating current dynamoelectric machines from a direct current power source that employs two inverter bridges controlled with a state vector modulation symmetrical state sequence that has a desired “chop” frequency so that each of their outputs produce a fundamental component that is exactly in phase but chop frequency components that are exactly 180 degrees out of phase with each other, with their outputs combined through respective interphase transformers to average the potentials of the chop frequency components.

Abstract: A motor controller having a damper that dampens resonance in a motor drive of a common mode filter to prevent it from becoming over excited by operation of the motor drive at a resonant frequency of the common mode filter. The damper is connected to an output feeder line of a motor drive in the motor controller and provides a common mode path to ground for the common mode filter. Thus, even if the motor drive is operating at a resonant frequency of the common mode filter, the resulting resonance in the common mode filter is attenuated by rather than amplified by the common mode filter, thereby preventing the common mode filter from excessive excitation.

Abstract: A generator feeder fault detection system includes a ground fault detector transformer that monitors the sum of forward and return currents from and to a generator. During normal operation, the sum of the currents in the ground fault detector equals zero. If there is a fault, however, the ground fault detector will detect a non-zero current sum. Because the ground fault detector measures the sum of the currents traveling through it, the current sensor in the detection circuit can be selected to measure small amounts of current and does not need to have a high threshold, even for generators that output high levels of current.

Abstract: A motor controller of the sort having both a transformation function for transforming three-phase feedback information into two components, and then changing an error signal for each of the two components back into three-phase correction numbers is provided with an ARCTAN correction function. The ARCTAN correction function takes in the time derivative of the changing angular position of the motor rotor, and creates a correction factor that is supplied back to the transformation function for changing the two error signals back into three. By supplying this correction ARCTAN function, the control eliminates a disturbance that may have occurred in the prior art at higher frequencies wherein both of the control loops for the two components needed to come into play to correct an error on either of the two loops.