Rockwell Automation Technologies Incorporated

Gennadi Sizov

Zoran Vrankovic

Gary Leonard Skibinski

Xikai Sun

Todd M Oestreich

David A Figie

Adam M Shea

Yao Da

Ahmed Mohamed Sayed Ahmed

Jingbo Liu

Robert H Schmidt

Michael J Melfi

Craig R Winterhalter

John Robert Figie

Mark Alan Gries

Kun Wei

Peter K Meyer

A system to reduce eddy currents and the resulting losses in a synchronous motor includes at least one pick-up coil mounted to the rotor. Each pick-up coil may be located proximate a pole on the rotor. A voltage applied to the stator to control the synchronous motor includes both a fundamental component and harmonic components. The fundamental component interacts with a magnetically salient structure in each pole on the rotor to cause rotation of the rotor. The harmonic components induce a voltage in the pick-up coil. The portion of the harmonic components that induce a voltage in the pick-up coil no longer generate eddy currents within the motor. The energy harvested by the pick-up coil may also be utilized in a function other than driving the motor, such as powering a sensor mounted on the rotor.

System and method for wireless power transfer to a rotating member in a motor

A motor drive that outputs a sinusoidal waveform utilizes power switching devices operable at high switching frequencies. The switching devices may be operated, for example, between twenty kilohertz and one megahertz. A first filter is included at the output of the motor drive which has a bandwidth selected to attenuate voltage components at the output which are at the switching frequency or multiples thereof such that the output voltage waveform is generally sinusoidal. Additional filtering is included within the motor drive to establish a circulation path for common mode currents within the motor drive. Further, a shield is provided adjacent to those components within the motor drive that may experience voltage or current waveforms at the switching frequency or multiples thereof to cause radiated emissions to establish eddy currents within the EMI shield rather than passing through the shield into the environment.

System and method for sinusoidal output and integrated EMC filtering in a motor drive

A motor controller executing a current regulator and a modulation routine in separate update intervals provides an improved fundamental voltage waveform for a motor controlled by the motor controller. The current regulator is executed at a first periodic update rate and the modulation routine is executed at a second periodic update rate, where the frequency at which the modulation routine executes is at least twice the frequency at which the current regulator executes. Executing the current regulator and the modulation routines at different frequencies results in the current regulator generating a single voltage reference signal for multiple periods of the modulation routine. To reduce voltage ripple induced by decoupling execution of the current regulator and the modulation routine, the motor controller extrapolates the voltage reference generated by the current regulator into multiple voltage reference signals, where a unique voltage reference signal is provided for each period of the modulation routine.

Voltage rotator for high switching frequency PWM inverter

A modulation routine in a motor drive under lightly loaded conditions which prevents DC bus voltage pump-up includes both active states and zero states. In a first zero state, each phase of the motor is connected to a negative rail of the DC bus, and in a second zero state, each phase of the motor is connected to a positive rail of the DC bus. When motor is lightly loaded or unloaded such that DC bus voltage pump-up may occur, the two zero states are utilized in an uneven manner. The specific division of the zero state between the first and second zero states may be selected in a manner that prevents the DC bus voltage pump-up from occurring.

Method and apparatus for mitigation of DC bus pump-up

A current regulator for a motor controller reduces distortion of the current output to a motor. Feedback signals corresponding to the current present on the motor are transformed into a fundamental and a harmonic reference frame. Notch filters in each reference frame attenuate components of the current feedback signal from the other reference frame. Current regulators in each reference frame receive the filtered current feedback signal in the corresponding reference frame and generate an output signal that is used to regulate the output current to the motor to the desired level of current in the corresponding reference frame. The output signal from the regulator in the harmonic reference frame is transformed to the fundamental reference frame, and the output of the two regulators are combined in a common reference frame to generate a reference signal corresponding to the required voltage output to the motor to achieve desired operation.

System and method for reducing current harmonic distortion in a motor controller

An IPM motor in which the absolute position of the rotor may be determined is disclosed. The IPM motor includes asymmetries in both the rotor and the stator. The rotor includes an asymmetrical pole configuration for one of the pole pairs in the rotor, and the stator includes a different number of turns for each winding of one phase of the motor. The different number of turns on each winding causes a different magnitude of flux to be generated with each winding. The flux interacts with the asymmetrical pole pair to identify to which winding the asymmetrical pole is proximate. A position sensing routine identifies an angular position with respect to each winding. The position sensing routine, in combination with the flux interaction between the windings and the asymmetrical pole provide an absolute position of the rotor within the IPM motor.

Permanent magnet motor with absolute rotor position detection

An electric motor in which at least one of the rotor and the stator has an asymmetric design is disclosed. The electric motor is divided into a number of segments, where each segment has an equal number of windings and an equal number of poles. The physical construction of each pole within a segment is identical and the number of turns of each winding within a segment is identical. The asymmetry is formed by varying the physical construction of the either the rotor or the stator within one segment from the corresponding construction of the rotor or stator in the other segments. The asymmetries are designed to improve one or more operating characteristics such as sensorless performance, torque ripple, or cogging torque in the motor.

Electric motor with asymmetric design for improved operation

A system to detect a ground fault at the output of an inverter section prior to powering up a motor drive system is disclosed. A low voltage power supply is connected to the DC bus prior to connecting the input power source to the rectifier section. If a ground fault exists, the voltage potential on the DC bus causes conduction through one of the freewheeling diodes connected in parallel to the power switching device on the output of the inverter section. A fault detection circuit generates a signal corresponding to the presence of the low voltage potential when the low voltage is applied to the DC bus. If a ground fault is present at the output of one of the inverter sections, the motor drive system prevents the AC voltage from being applied to the rectifier section.

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Shorewood, WI, United States of America

Gennadi Sizov