Abstract: A system and method of controlling the power factor for providing either unity, leading or lagging results for the sensorless control of synchronous machines. The system and method provides an estimated angle of the phase current Park vector and uses a floating synchronous reference frame that is shifted from the estimated angle of the phase current Park vector by an angle ? to allow the active control and change of the power factor during operation for applications such as producing reluctance torque of a salient pole synchronous machine during Main Engine Start (MES), and field weakening for Environmental Control Systems (ECS) and MES applications.

Abstract: A system and method is provided for generating DC power using a synchronous reluctance machine (12) or a salient-pole synchronous machine (102) and a power converter (110). The present invention can be used to achieve power production for a synchronous reluctance machine (12), or can be used to achieve partial production of power from a traditional salient-pole synchronous machine/starter (102) in the case where the salient-pole synchronous machine/starter has degenerated into a synchronous reluctance machine due to, for example, a loss of excitation. In a power generation system, a control system and method can include a power converter (110), controlled by a voltage command and at least one of a measured DC link (120) voltage or DC link (120) current, for use with a synchronous reluctance machine armature winding (102A) and a prime mover (116), such that movement of the synchronous reluctance machine rotor of the synchronous reluctance machine can be used to produce at least partial DC power generation.

Abstract: A system and method is provided for generating AC power using a synchronous reluctance machine (12) or a salient-pole synchronous machine (102) and a power converter (110). The present invention can be used to achieve power production for a synchronous reluctance machine (12), or can be used to achieve AC power from a traditional salient-pole synchronous machine/starter (102) without dependence upon a rotor current which is subject to failure. In the power generation system, the control system and method can include a power converter (110), controlled by a voltage command and at least one of a measured AC bus (125) current and voltage, and a DC link (120) voltage, for use with a synchronous reluctance machine (102) and a prime mover (116), such that movement of the rotor of the synchronous reluctance machine (102) can be used to produce at least partial AC power generation on the AC bus (125).

Abstract: A system and method is provided for generating AC power using a synchronous reluctance machine (12) or a salient-pole synchronous machine (102) and a power converter (110). The present invention can be used to achieve power production for a synchronous reluctance machine (12), or can be used to achieve AC power from a traditional salient-pole synchronous machine/starter (102) without dependence upon a rotor current which is subject to failure. In the power generation system, the control system and method can include a power converter (110), controlled by a voltage command and at least one of a measured AC bus (125) current and voltage, and a DC link (120) voltage, for use with a synchronous reluctance machine (102) and a prime mover (116), such that movement of the rotor of the synchronous reluctance machine (102) can be used to produce at least partial AC power generation on the AC bus (125).

Abstract: A system and method is provided for generating DC power using a synchronous reluctance machine (12) or a salient-pole synchronous machine (102) and a power converter (110). The present invention can be used to achieve power production for a synchronous reluctance machine (12), or can be used to achieve partial production of power from a traditional salient-pole synchronous machine/starter (102) in the case where the salient-pole synchronous machine/starter has degenerated into a synchronous reluctance machine due to, for example, a loss of excitation. In a power generation system, a control system and method can include a power converter (110), controlled by a voltage command and at least one of a measured DC link (120) voltage or DC link (120) current, for use with a synchronous reluctance machine armature winding (102A) and a prime mover (116), such that movement of the synchronous reluctance machine rotor of the synchronous reluctance machine can be used to produce at least partial DC power generation.

Abstract: A method and system for controlling a power converter coupled to a polyphase power line. The method includes measuring at least two motor phase currents, obtaining a floating reference frame for the current Park vector, adjusting the reference frame based on an estimated rotor speed, and controlling the power converter via the floating reference frame to reinitiate power to a motor while a rotor is still moving.

Abstract: A system and method is provided for overload and fault current protection of a permanent magnet generator. The system comprises a permanent magnet machine, a DC link, an inverter, coupled between the permanent magnet machine and the DC link, and a controller adapted to provide a linear decrease in voltage for the DC link when the permanent magnet machine is in at least one of an overload and fault current condition.

Abstract: A system and method is provided for starting a prime mover coupled to a synchronous starter/generator. The system includes an exciter converter that provides a non-fundamental only signal to a field winding of an exciter of the synchronous generator. The non-fundamental signal provides a first rotating field for the field winding of the exciter. Exciter armature windings induce an AC signal from the rotating field where at least one rectifier rectifies the induced AC signal. A field winding of a main machine provides a flux from the rectified signal of the at least one rectifier. Armature windings of the main machine receive an AC signal via a main machine converter.

Abstract: A system and method for an autotransformer configuration including a plurality of windings which can be used to provide a substantial reduction in harmonics. The autotransformer includes a series of wye windings configured to provide a constant length voltage vector for any given input voltage, and a series of delta windings having a variable length voltage vector based upon turns ratio. The delta winding circuit is electrically coupled with the wye winding circuit to allow circulation of triplen harmonics, thereby reducing the effect on input current waveform such that total harmonic distortion (THD) is reduced, and producing an equivalent kVA rating that is lower than prior art applications, which results in savings in size, weight and cost.

Abstract: A synchronous motor controller and method of controlling a synchronous motor without using rotor position sensors are provided. In a floating synchronous reference frame controller, phase currents are measured and a current Park vector is determined. The error between an initially arbitrary floating reference frame is reduced with a control loop. Decoupling terms based on the estimated speed of the rotor and the stator winding inductance are used to generate decoupled voltage terms in the v- and u-axis of the floating synchronous reference frame. The decoupled voltage command is converted back to a stator reference frame and applied to the synchronous motor via a power electronic converter. As a result u-axis current is minimized during transients, and a robust and accurate estimation of the current vector to be used in coordinate transformation for controlling the machine are achieved and the need for overrating of motor and inverter components is avoided.

Abstract: A system and method for using reluctance torque or a combination of both reluctance and reaction torque components of an attached synchronous machine (102) to accelerate a prime mover (116), such as a gas turbine engine, within a desired start time. The system selects a mode of starting operation, and thereafter applies reluctance torque through a synchronous machine (102) armature winding (102A) excitation as a single, sufficient starting force in a first mode, or staged reluctance and reaction torque through the additional excitation of the synchronous machine (102) field winding (102B) excitation in a second mode, using existing power electronics and controls.

Abstract: A system and method to provide an improved power electronics starting system (100) in which starting torque is delivered by a salient pole synchronous machine (102), while associated power electronics (110) and (118) utilization is maximized by adjusting the Park vector of the armature (102A) phase current to remain in-phase with the Park vector of the armature (102A) terminal voltage, regardless of the level of saturation of the pole synchronous machine (102).

Abstract: A system and method is provided for overload and fault current protection of a permanent magnet generator. The system comprises a permanent magnet machine, a DC link, an inverter, coupled between the permanent magnet machine and the DC link, and a controller adapted to provide a linear decrease in voltage for the DC link when the permanent magnet machine is in at least one of an overload and fault current condition.

Abstract: A system and method is provided for starting a prime mover coupled to a synchronous starter/generator. The system comprises an exciter converter that provides a non-fundamental only signal to a field winding of an exciter of the synchronous generator. The non-fundamental signal provides a first rotating field for the field winding of the exciter. Exciter armature windings induce an AC signal from the rotating field where at least one rectifier rectifies the induced AC signal. A field winding of a main machine provides a flux from the rectified signal of the at least one rectifier. Armature windings of the main machine receive an AC signal via a main machine converter.

Abstract: A system and method for using reluctance torque or a combination of both reluctance and reaction torque components of an attached synchronous machine (102) to accelerate a prime mover (116), such as a gas turbine engine, within a desired start time. The system selects a mode of starting operation, and thereafter applies reluctance torque through a synchronous machine (102) armature winding (102A) excitation as a single, sufficient starting force in a first mode, or staged reluctance and reaction torque through the additional excitation of the synchronous machine (102) field winding (102B) excitation in a second mode, using existing power electronics and controls.

Abstract: A system and method to provide an improved power electronics starting system (100) in which starting torque is delivered by a salient pole synchronous machine (102), while associated power electronics (110) and (118) utilization is maximized by adjusting the Park vector of the armature (102A) phase current to remain in-phase with the Park vector of the armature (102A) terminal voltage, regardless of the level of saturation of the pole synchronous machine (102).

Abstract: A power generation system includes multiple generators that are operated in parallel. An inverter of one of the generators is always operated in voltage mode. Inverters of the other generators are switched between voltage and current modes.

Abstract: A fault tolerant controller arrangement for electric motor driven apparatus is implemented by a plurality of control channels, each of which includes a motor and associated drive circuitry. The implementation is such that the rating of each of the plurality of channels is reduced and all channels are operated such that the load is shared between all operating channels. The arrangement is such that all channels share the load dynamically and statically and that each channel in a system of n channels supplies .sup.1 n of the required load driving force in the same direction.

Abstract: A hybrid servomechanism includes a speed control, a rotor position control and a brushless motor. When enabled, the position control commands a stationary stator mmf vector, allowing the motor's rotor to rotate until load torque and motor torque are balanced. This position control eliminates limit cycle operation and allows the motor to compensate for backdriving caused by external loads.

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.