Sundstrand Corporation

Madan L Bansal

Gregory I Rozman

Albert L Markunas

Shan-Chin Tsai

Jayant G Vaidya

Alexander Krinickas, Jr

William A Byrd

Alexander Cook

William S Heglund

Hassan Mansir

Pierre S Thollot

Paul E Nuechterlein

Barry J Parker

Mario R Rinaldi

The invention is an induction electrical power generation system for generating alternating current varying within a frequency range; the system includes an induction electrical generator (52) for generating the alternating current having a rotor and a stator, the stator having at least one phase winding for outputting the generated alternating current and a plurality of poles with at least two different numbers of poles within the plurality of poles being selected to generate the alternating current, an exciter winding wound on the stator which is driven by AC excitation which varies in frequency during generation of the alternating current and the rotor operating with slip during the generation of the alternating current; a variable speed drive coupled to the rotor for driving the rotor in a speed range during generation of the alternating current; an exciter generator (54) coupled to the exciter winding for generating the variable frequency AC excitation; a speed sensor (56) for producing a signal which is a function of the speed of rotation of the rotor; and a controller (58), coupled to the inverter and responsive to the rotor speed signal, for commanding variation of the excitation frequency as a function of the rotor speed signal, a selection of the at least two different numbers of poles within the plurality of poles as a function of the rotor speed signal to control generation of the alternating current within the frequency range and a magnitude of excitation current produced by the exciter generator.

Induction electrical power generating system with variable numbers of

A multiple output synchronous generator in accordance with the instant invention comprises a stator having a first stator winding having a number of poles p and a second stator winding having a number of poles 2*p*n where p and n are any whole numbers, the first and second stator windings being wound utilizing a 60.degree. phase belt winding configuration such that the first stator winding is magnetically decoupled from the second stator winding preventing interaction therebetween. The generator additionally comprises a rotor rotatably disposed within the stator defining an airgap therebetween. The rotor has a first field winding of a first polarity and a second field winding having a second number of windings wound thereon for generating a flux across the airgap such that the flux induces a voltage in the first and second stator windings. These first and second field windings are configured such that the flux generated in the airgap comprises a fundamental component and an even harmonic component of substantially equal magnitude. The winding configuration of the stator and rotor insure that only the fundamental flux component and odd harmonics induce a voltage in the first stator winding, and only the even harmonic component and even harmonics induce a voltage in the second stator winding. The magnetic decoupling of the first and second stator windings ensures that harmonic distortion induced in the second output by external equipment powered thereby is not reflected in the first output, thereby maintaining a 'clean-bus' for use by utilization equipment sensitive to such distortion.

Multiple output decoupled synchronous generator and electrical system

An electric power starter generator system comprises a synchronous generator and an induction motor/generator mutually coupled to a shaft being driven to an external prime mover. The synchronous generator and the induction motor/generator are driven by the shaft at the same speed. The system includes a rectifier/inverter having ac terminals coupled to the output of the induction motor/generator, and dc terminals coupled to a dc bus. This rectifier/inverter allows bi-directional power flow to effectuate both power generation as well as electric start of the prime mover. The synchronous generator is excited by a commonly driven permanent magnet generator and a modulated exciter field control. The induction motor/generator is self-exciting through the rectifier/inverter once a voltage is established on the dc bus. The establishment of this voltage may be accomplished by a battery, or by connection of the synchronous generator's output to the input of the rectifier/inverter through a poly-phase contactor. This contactor also allows cross connection of either machine to either distribution bus if one of the machines were to fail, or if the loading on that particular bus became excessive.

Dual output synchronous-induction starting/generating system

The present invention provides for detecting rotor speed through the use of sense coils on the stator teeth. Voltage ripples caused by the rotor slots is detected by combining the signals of several such sense coils so that the fundamental voltage signal is cancelled or rejected and only the ripple voltages remain, a signal proportional to rotor speed. Several alternative methods for implementing that technique are discussed herein. At low induction motor speeds, the present invention filters out the voltage ripples and incident third harmonics and instead estimates rotor speed from the fundamental voltage. When the induction motor is already being driven by a prime mover, the present invention selects a proper initial frequency command for initial motor start by identifying rotor speed from the PWM inverter. Further, the present invention provides for using a generator to control voltage to the induction motor, with a PWM inverter to control frequency signals to the induction motor.

Method and apparatus for controlling induction motors

The problem of providing isolated DC power in a 270 volt DC power system (10) has been resolved with the use of a DC--DC converter (44) for providing isolated DC power on busses (46-48) for powering pulsating loads (66), avionics DC loads (68) and AC loads (64). The use of the converter (44) further allows for reduction in size of ripple filters (92-94) and damper circuits (50-52).

Hybrid 270 volt DC system

The problem of filtering DC power on a DC bus (46) in an electrical power generating system (10) is resolved using an active damper circuit (44). The active damper circuit (44) comprises a capacitor (CD) and a switching circuit (70) for alternately switching the capacitor (CD) into and out of parallel relationship with the DC bus (46).

Electric power generating system with active damping

The problem of stator cooling in a dynamoelectric machine is resolved using manufacturing spaces (32) within stator slots (20) for flow of oil coolant. In order to secure stator winding conductors (30) within the slots, a spring wedge (36) provides a biasing force for biasing the conductors against movements within the slots.

Dynamoelectric machine oil-cooled stator winding

In a dynamoelectric machine which includes a rotor and a stator, an integral magnetic isolation and cooling system. A housing is disposed about the machine, the housing being fabricated of magnetically permeable material to define a flux path therethrough. A cooling jacket is sandwiched between the housing and the stator. The cooling jacket has coolant passages therein and is fabricated of non-magnetic material to isolate the flux path between the housing and the stator.

Magnetic isolation and cooling system in dynamoelectric machines

An improved alternating current machine having interdispersed armature windings is disclosed. The AC machine comprises an armature core having a plurality of generally longitudinal slots and a plurality of winding groups. Each of the winding groups comprises a plurality of one-turn coil windings which are series connected to electrically adjacent windings of the winding group. Each winding has two generally parallel side portions disposed in non-adjacent ones of the slots. The side portions are joined at one end by an end turn which extends axially outward from one end of the armature core and each of the side portions have an end connection extending a distance axially outward from the other end of the armature core for connecting to a respective electrically adjacent end connection of its electrically adjacent winding. The winding groups are interdispersed about the armature core such that there are a plurality of fixed distances between the electrically adjacent windings. The end connections extend outwardly from the armature core a plurality of distances, and the distance which each particular one of the end connections extends is proportional to the distance between the particular end connection and its electrically adjacent end connection to which it is series connected.

Compact connections for interdispersed armature winding

A high-power, high-voltage DC power supply includes a plurality of AC generators, each of which includes a rotor and one or more sets of armature windings wherein the rotors are linked together. A plurality of rectifiers are connected together in series and the armature windings are connected to the rectifiers such that each rectifier produces a fractional voltage which is combined with the fractional voltage developed by other rectifiers to develop a combined output voltage across all of the rectifiers. The armature windings are placed relative to one another such that a plurality of equally-spaced ripple peaks appear in the combined output voltage for each 360.degree. of each armature winding voltage. This in turn minimizes ripple magnitude leading to a desirable decrease in the overall power supply size and weight.

High-power, high-voltage direct current power source

In order to improve the efficiency of electric machines, by reducing losses caused by eddy currents induced by high frequency fluxes, the outer surface of the rotor, including the rotor pole face, has a plurality of circumferential grooves. The grooves are provided in axially spaced relation along the rotor. Preferably, the method of reducing losses includes the step of forming the grooves by laser cutting, which permits the width and spacing of the grooves to be minimized so as to maximize loss reduction by increasing resistance to eddy currents.

Growing community of inventors

Rockford, IL, United States of America

Madan L Bansal