Rockwell Automation Technologies Incorporated

Reliance Electric Technologies, LLC

Reliance Electric Industrial Company

Robert J Breitzmann

Semyon Royak

Thomas Arthur Nondahl

Peter B Schmidt

Jingbo Liu

Mark Melvin Harbaugh

Jingya Dai

John M Kasunich

Lixiang Wei

Russel J Kerkman

Richard Lukaszewski

Haihui Lu

Ahmed Mohamed Sayed Ahmed

Michael J Melfi

Zhenhuan Yuan

Ehsan Al-Nabi

Shaofeng Zhang

John James Jenks

Thomas M Cahill

Disclosed examples include power conversion systems and methods to operate an inverter to drive a motor load through an intervening output filter, a transformer and a cable, including a current regulator to compute a command value according to a current reference value and a motor current feedback value, a cross-coupled feedforward component to compensate the command value by an estimated cross-coupled voltage value to compute a control output value, a cross-coupled object component to compute the motor current feedback value according to a voltage value using a plant transfer function representing the output filter, the transformer, the cable and the motor load, and a controller to provide the inverter switching control signals to control the inverter according to the control output value.

Feedforward control of motor drives with output sinewave filter

Disclosed examples include power conversion systems, methods and computer readable mediums to operate an inverter to drive a motor load through an output filter, in which a control output value is computed according to a current reference value and a current feedback value using a proportional-integral (PI) current regulator, the control output value is filtered using a lag compensator filter to compute an inverter output command value, and the inverter is controlled according to the inverter output command value.

Current control of motor drives with output sinewave filter

Methods and systems are presented for closed loop motor speed and torque control without a sensor at the motor, in which configuration parameters are received from a user interface to define operating characteristics of a filter, a transformer, a cable, and the motor coupled with the output of a motor drive, and an object model of the motor drive is configured according to the filter, transformer, cable and motor configuration parameters to facilitate sensorless closed loop motor speed and/or torque control.

Methods and systems for sensorless closed loop motor speed and torque control

Methods and apparatus are presented for unintentional islanding detection for grid tie converters in which the phase angle disturbance is introduced by modification of grid side converter switching control signals and a mismatch of reactive power between generation and the grid load is formed upon the occurrence of unintentional islanding, where the applied phase disturbance is determined according to two pre-defined curves to form an equivalent positive feedback at different frequencies to prevent the converter from forming an island at a new stable frequency after the grid is disconnected.

Method and apparatus for islanding detection for grid tie converters

Apparatus and methods are provided for detecting degradation of delta-connected filter capacitors in an active front end (AFE) power converter, in which delta circuit capacitor leg currents are calculated based on measured branch circuit currents, and filter capacitor impedance values are computed based on the calculated leg currents as well as measured line-to-line voltages and corresponding phase angles for comparison with one or more thresholds to selectively detect degradation of the filter capacitors. Further apparatus and methods are provided for detecting degradation of Y-connected filter capacitors by computation of fundamental frequency RMS impedance values as ratios of RMS capacitor voltages and RMS circuit branch currents, and comparison of the calculated RMS impedance values with one or more thresholds.

Methods and apparatus for active front end filter capacitor degradation detection

Apparatus and methods are presented for mitigating overvoltages and limiting reverse motor speeds for motor drive power loss events, in which a first power dissipation circuit is enabled at the motor drive output to limit reverse rotation of a driven motor load when motor drive power is lost, and a second power dissipation circuit in a DC bus circuit is used to mitigate over voltages following restoration of motor drive power.

Method and apparatus for overvoltage protection and reverse motor speed control for motor drive power loss events

Active front end power conversion systems are presented having a peak detector with adjustable decay providing a signal to an overload protection component to selectively discontinue rectifier switching control signals for protection of active rectifier switches during unbalanced line voltage conditions.

Active front end power converter with diagnostic and failure prevention using peak detector with decay

The present invention provides an improved current regulator for PWM based drives for electric motors. The invention provides compensation for the rotor position signal for delays introduced due to the PWM algorithm and for digital sampling present in such a drive. Current regulator commonly operate in a two-phase reference frame, requiring forward and reverse coordinate transformations between the physical current values and the two-phase reference frame variables. The present invention provides an improved compensation in the forward transformation by determining the phase lag between the commanded voltage reference and the output voltage reference and by further compensating the forward transformation for errors introduced due to sampling the current either at different sampling instances than the rotor position or at multiple sampling instances during a carrier period. Additionally, compensation during the reverse transformation is provided to compensate for errors introduced due to sampling the current and rotor position.

Method and apparatus for increased current stability in a PWM drive

Active power converters and methods are presented for converting input electrical power to output electrical power with converter switching control in which the individual phase voltage command values are compensated according to phase line voltage imbalances to compensate the converter control to provide balanced phase currents in the presence of unbalanced phase supply line voltages.

Method and apparatus for phase current balance in active converter with unbalanced AC line voltage source

The invention includes a motor controller and method for controlling a permanent magnet motor. In accordance with one aspect of the present technique, a permanent magnet motor is controlled by, among other things, receiving a torque command, determining a normalized torque command by normalizing the torque command to a characteristic current of the motor, determining a normalized maximum available voltage, determining an inductance ratio of the motor, and determining a direct-axis current based upon the normalized torque command, the normalized maximum available voltage, and the inductance ratio of the motor.

Universal adaptive torque control for PM motors for field-weakening region operation

A method and apparatus for altering converter control as a function of the degree of unbalance in supply line voltages to substantially eliminate second harmonics on the supply lines caused by active control of the converter including identifying supply line peak amplitude values and using the peak values to identify potential second harmonics and then altering command values as a function of the potential second harmonic components.

Method and apparatus for rejecting the second harmonic current in an active converter with an unbalanced AC line voltage source

In accordance with certain embodiments, the present technique provides a reduced current field-oriented-control scheme. For example, the present technique provides a method of controlling an induction device in which a predetermined reduction factor is employed to reduce the flux-current vector of a field-oriented-control scheme. By reducing this vector, less current and less power are drawn by the induction device, in turn reducing resistive heating and stator core losses, for instance.

Modified field oriented control

A system for synchronizing a plurality of motors is disclosed. The system includes a universal drive controller which can control the operation of two motors, a power module for each motor, and a power module interface rack which is utilized to interconnect the motor to its associated universal drive controller. If a plurality of universal drive controllers is involved, a common clock is utilized to synchronize the operation of same. Synchronization of the motors is achieved by monitoring the output shaft of each motor through the use of a resolver, transmitting feedback data relative to the position of the output shaft to the universal drive controller via the power module interface rack, calculation of command data by the universal drive controller to effect synchronization, and transmitting the command data to the power module interface rack wherein the power module causes the proper firing signals to be transmitted to the associated motor. Since the operation of the universal drive controller is synchronized, and each motor is synchronized to its associated universal drive controller through its associated power module interface rack, the operation of all of the motors is synchronized.

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South Russell, OH, United States of America

Robert J Breitzmann