Abstract: The invention relates to a method of starting an asynchronous machine irrespective of whether the rotor of the machine is rotating or not when the machine is supplied by an inverter provided with a separate moment and flux or moment and magnetizing current control, which is faster than the time constants of the asynchronous machine. According to the invention, zero moment is set as a target for the control, a voltage is supplied to the stator of the machine by the inverter, a stator current vector and a stator flux generated by the voltage is determined, an estimate of that vector or some other quantity comparable to the stator flux is determined, a moment caused by the stator flux vector and the stator current vector is determined and information of the moment is supplied to the control, which tries to zero the caused moment by making the stator flux and a rotor flux generated thereby cophasal, thus synchronizing the supply frequency of the inverter with a possible rotation of the machine rotor.

Abstract: A conventional full wave diode bridge of an alternator is replaced with a full wave controlled rectifier bridge having controlled switches in place of diodes. Phase control is performed by the switches of the controlled rectifier bridge to preempt natural commutation and shift the phase of the alternator phase voltages relative to the phase currents. The phase angle control disrupts the normal unity power factor operation of the alternator and causes additional reactive current flow in a three phase stator winding of the alternator to source the controlled rectifier bridge. The result is that for the same operating conditions the controlled switches of the controlled rectifier bridge boost output from the alternator by from 40% to 60%.

Abstract: The present invention relates to a device which supplies a field current to the field coil of an alternator for a vehicle in a gradually changing manner. In the device, a pulse voltage which has a pulse width corresponding to a phase difference between output signals of first and a second counters (15 and 16) is generated by a maximum duty ratio limiting circuit (19). When the alternator output voltage becomes higher than a reference voltage, the full-scale count time of the second counter is shortened relative to the full-scale count time of the first counter. On the other hand, when the output voltage becomes lower than the reference voltage, the same is elongated to thereby increase the phase difference. A switching transistor (12) is provided to control the field current supplied to the alternator field coil in response to the above pulse voltage.

Abstract: The stabilizer for power system is capable of suppressing power unstableness quickly and functioning effectively to a plurality of power disturbances even if the non-linearity of the power system becomes more intense because the stability point is moved from optimum stability. A phase difference calculating circuit calculates the phase difference between the internal phase angle of a generator and the voltage phase in a secondary bus line of a main transformer connected to a synchronous generator. A power system stabilizer produces an auxiliary signal based on the output of the phase difference calculating circuit. A first nonlinear compensating circuit and a second nonlinear compensating circuit produce compensating signals for compensating the non-linearity of the power system in order to compensate the output of the power system stabilizer.

Abstract: A method of producing electrical energy from rotary motion of an axle of a vehicle utilizes a generator assembly including a generator coupled to the axle. The method includes determining the rate of rotation of the axle, carrying out the electrical energy production as well as the determination of the rate of rotation exclusively through the generator, and evaluating pulse parameters of each induced electrical voltage pattern for the determination of the rate of rotation. The generator assembly includes a rotor coupled to the axle and permanent magnets mounted on the rotor distributed over the circumference thereof. The permanent magnets have radially extending polar axes. A stator includes induction coils mounted coaxially around the circumference of the rotor. An air gap is defined between the stator and the rotor.

Abstract: An out of phase detecting apparatus according to the present invention includes a measurement unit for measuring an effective power and a current effective value at a tie point of power systems at a predetermined cycle, a power trend detection unit for detecting a trend of the effective powers measured in sequence by the measurement unit, a current trend detection unit for detecting a trend of the current effective values measured in sequence by the measurement unit, a power level determination unit for determining a relationship in strength between each of the measured powers and a steady effective power P.sub.0 obtained when the power systems are in a steady state, and an out of phase detection unit for detecting whether an out of phase condition occurs in the power systems based on the trend of the measured effective powers, the trend of the measured current effective values, and the relationship in strength between the steady effective power P.sub.0 and each effective power.

Abstract: A rotary induction generator having a stator with stator windings defining a three-phase stator and a rotor mounted for rotation therein, and having wound thereon three rotor windings defining a three-phase rotor and having resistive-reactive means connected to said secondary windings to increase the efficiency of said generator and limit the power output to the capacity of the generator over a wide range of speeds.

Abstract: A detector for detecting rotor position of a brushless generator having a motive power shaft, a permanent magnet generator (PMG) having a set of armature phase windings and a main generator portion having a set of armature phase windings includes a circuit coupled to the armature phase windings of the main generator portion for deriving a number of interval pulses per revolution of the motive power shaft. A circuit measures time periods between adjacent interval pulses and the measured time periods are converted into an indication of the angular position of the motive power shaft in accordance with a parameter of power delivered to the main generator portion armature phase windings.

Abstract: A method of producing electrical energy from rotary motion of an axle of a vehicle utilizes a generator assembly including a generator coupled to the axle. The method includes determining the rate of rotation of the axle, carrying out the electrical energy production as well as the determination of the rate of rotation exclusively through the generator, and evaluating pulse parameters of each induced electrical voltage pattern for the determination of the rate of rotation. The generator assembly includes a rotor coupled to the axle and permanent magnets mounted on the rotor distributed over the circumference thereof. The permanent magnets have radially extending polar axes. A stator includes induction coils mounted coaxially around the circumference of the rotor. An air gap is defined between the stator and the rotor.

Abstract: A power utility system includes a generator driven by a prime mover in response to a mechanical input power and an excitation to provide an electrical output power. The excitation of the generator is controlled in response to an estimated equilibrium rotor angle. The estimation of the rotor angle is based on purely local measurements. This estimated rotor angle is used in conjunction with a feedback linearizing controller to provide field excitation control of the generator. The rotor angle reference signal is also used to provide a rotor angle error signal to a power system stabilizer which is modified to operate on the basis of an angle error rather than a speed or frequency error.

Abstract: In an electrical supply network containing a generator, critical fluctuations in real power can occur. The load angle of the generator is representative of these fluctuations. The present invention provides a method which measures the real and reactive power flow, the current and the voltage on a line to the generator and feeds these measured values along with reactance values Y.sub.L and Y.sub.Q of the generator and line to a computing device. The computing device determines an output signal .delta. which represents the load angle of the generator and fluctuations in real power. The output signal .delta. is provided to an indicating device and/or a reactive power compensator.

Abstract: The problems of minimizing size and weight in aircraft and avoiding requirements for custom design are minimized in a digital voltage regulator circuit (120).The circuit (120) includes a programmed processor circuit (124) having a memory circuit (138), and a drive circuit (132) operatively coupled with the processor circuit (124) for developing an exciter control signal.This circuit (120) is manufactured using custom very large scale integration (VLSI) technology to reduce size, weight, life cycle costs and improve reliability.

Abstract: A power system stabilizer (PSS) to bring the constant in a phase lead-lag circuit of the PSS to an optimum value by having such procedures carried out in its phase lead-lag compensation circuit as to apply the ruler to lead the phase of the PSS when the period of the power fluctuation in each mode tends to decrease and to lag the phase of the PSS when conversely the period tends to increase by means of a fuzzy inference device to detect results of the periods weighted by the degrees of the tendency, to superpose the outputs obtained by application of the rule to obtain the center of gravity, and therewith finally to vary the constant in the amplification and phase lead-lag circuit of the PSS.

Abstract: This invention relates to a power system stabilizing apparatus for a synchronous generator, which comprises two power system stabilizers for raising the stability of an electric power system. The characteristics of one stabilizer is preset so as to increase the braking power in the same way as in a conventional power system stabilizing apparatus, while the other one being preset so as to increase the synchronizing power, so that phase compensation elements of both power system stabilizers can be varied in accordance with the drift amount of the generator such as the revolution deviation of the rotor thereof, the output deviation thereof, the frequency deviation of the terminal voltage thereof, etc. thereby realizing high static and transient stability.

Abstract: Before a synchronous machine is connected with a line, the set value of a voltage setter is controlled so that the difference between the line voltage and the set value of the voltage setter is decreased to zero, and a field current is then controlled so that the difference between the set value and the output voltage of the synchronous machine is decreased to zero, thereby parallel-connecting the synchronous machine with the line.

Abstract: A self-excited brushless alternator having a rotating field excited by an alternating current exciter whose armature rotates with the field winding of the alternator and is permanently connected to that winding by a rotating field rectifier. To obtain reliable regulation over a wind range of load and power factors, at least one exciter stator primary winding is magnetically coupled to at least one exciter rotator secondary winding which is connected by the rectifier to the main field. Primary excitation direct current for the exciter is derived by a magnetic coupling from a rotary auxiliary magnetic field produced by a feedback winding connected in series with the main field winding and rotating therewith. Preferably, current paths for the exciter primary excitation are different during and after build-up.

Abstract: A power factor controller for alternating current/direct current drilling rigs is provided which utilizes a uniquely controlled, unloaded, over-excited generator to provide reactive power to maintain the rig's power factor within prescribed limits during peak demand operations.

Abstract: This invention is directed to a digital feedback control system. The control system includes a controlled device which generates an output signal representative of the operation of that device, with that output signal being a relatively high frequency carrier signal having a relatively slowly varying (compared to the carrier signal) envelope. The control system further includes a difference network for generating an error signal representative of the difference between an input command signal and a sensor signal derived from the output signal of the controlled device. A feedback network is responsive to the output signal to provide the sensor signal. The feedback network includes a selectively operative integrator which generates an integrated signal representative of the integral of the output signal. The feedback system further includes a selectively operable network for resetting the integrator.

Abstract: An electrical distribution system has parallel connected generators powered by variable speed engines. Loads connected with each generator are interconnected through an electrical distribution bus. Constant speed drives have inputs connected with the engines and outputs directly connected with the generators. The connections between the constant speed drive outputs and the generators are characterized by the absence of overrunning clutches used in prior systems. An improved electrical protective circuit senses a flow of electrical power from the distribution bus to a generator, driving the generator as a motor. If the power flow to the generator is excessive, the bus tie breaker is opened disconnecting the generator from the bus.

Abstract: A power factor controller for alternating current/direct current drilling rigs is provided which utilizes a uniquely controlled, unloaded, over-excited generator to provide reactive power to maintain the rig's power factor within prescribed limits during peak demand operations.

Abstract: A motor driven generator has a generator control unit which incorporates a programmed microprocessor to control generator operation. A generator voltage regulator utilizes the microprocessor of the generator control unit to develop an error voltage which is added to the average phase voltage of the generator, controlling the generator field current. In the event of a phase failure the generator control unit senses an abnormally high phase voltage condition, disables the average phase voltage circuit. In the event of an abnormal difference between the high and low phase voltages, the gain of the error signal circuit is reduced.

Abstract: The input signal corresponding to the respective frequency or power variation is supplied both to the inputs of the discrete filters and to angle measuring devices assigned to them, of which only the tuned filter in conjunction with its angle measuring device actuates a switch which sends the filter output via angle rotating and matching elements to a MAX selector element, from which the supplementary damping signal for the excitation is tapped. For low oscillation frequencies a low-press filter is provided which, via mean value formers and time delay multivibrator stages, permits a regulator signal to become operative for the excitation, delayed or undelayed, when certain limit values are exceeded.

Abstract: A digital electronic governor controls and stabilizes the electrical power output delivered to an output circuit by an AC alternator having a rotating shaft driven by a source. The governor provides a first relatively fast acting governing function operatively responsive to phase shift of the electrical power output relative to the rotating shaft corresponding to changes in load at the output circuit. The first governor stabilizes the phase shift of the electrical power output at a specified phase lag interval relative to the shaft rotation. The electronic governor also provides a second governing function operatively responsive to relatively slower inertial changes in the speed of rotation of the shaft, corresponding to changes in the power level of the AC alternator. This second governor stabilizes the rotating shaft at a specified speed of rotation, e.g., 60 cycles per second. The first governor generates load signals in response to the measured phase shift deviation from a standard phase lag interval.

Abstract: A discrete-time, closed loop power factor corrector system controls the coupling of a delta-connected switched capacitor array to a 3- or 4-wire power line which may have time-varying, unbalanced, inductive loads. For inductive loads that cannot be exactly compensated with a delta-connected capacitance, the corrector system minimizes the total RMS reactive current drawn from the power line.

Abstract: A shaft torsional oscillation signal of a rotatable torsional system including a rotor of a synchronous machine, at least one rotatable body and a shaft coupling the synchronous machine and the rotatable body, is detected. The shaft torsional oscillation signal with a specific frequency is made to advance the phase thereof by a stabilizing control device. The field voltage of the synchronous machine is so controlled that a sub-synchronous resonance (SSR) of the rotatable torsional system caused by the specific frequency is restrictedly controlled by the shaft torsional signal of the specific frequency phase-advanced.

Abstract: A field control apparatus for a generator having a field winding comprises a terminal voltage control unit for controlling a field current of the generator in accordance with a difference between a terminal voltage signal of the generator and a reference voltage signal, which control unit has at least one of a line drop compensation function, an under-excitation limitation function, an over-excitation limitation function, a power factor regulation function, an armature winding over-current compensation function and a cross-current compensation function. The field control apparatus includes a detector as a common signal source for detecting active power and reactive power components at an output terminal of the generator and means responsive to the output of the detector for performing scalar operation in accordance with a function of the added compensation/control function described above.

Abstract: An electronic circuit is provided for regulating a three-phase generator which includes: a circuit for sensing the average of the three-phase voltages; a circuit for sensing the highest phase voltage; and a circuit for sensing the highest phase current. The output of each of these circuits is compared to reference currents which represent an average voltage setting and high phase voltage and current limits, and an error signal is generated that is integrated over time. The integrated error signal is utilized as input to a comparator circuit which generates a pulsewidth modulated signal that represents deviation from the desired operating parameters. The pulsewidth modulated signal is applied to an output amplifier circuit which in turn serves to control the current through the generator's exciter field. An exciter field current detector is connected between the output amplifier and the input of a gain and compensation circuit in order to provide a negative current feedback circuit to minimize transients.

Abstract: In a power system, control signals derived from a measurement of dynamoelectric machine output voltage and current are selectively applied to an exciter to control the current in a field winding of the machine to control the machine reactive volt-amperes and output voltage.

Abstract: The field excitation flux of the synchronous generator is controlled in response to the summing rotor angle signal of a predetermined set signal and of a rotor angle signal representing a phase difference between the voltage equivalent to an infinite bus voltage and the output voltage from the pilot generator provided on the same rotating shaft as the synchronous generator.