Caterpillar Inc.

James Michael Thorne

Jackson Wai

Jesse R Gerdes

Ahmed Khalil

Seok-hee Han

Sangameshwar Sonth

Amara Ashfaq

Sajan Abdul

Carlos Eduardo Nino Baron

Ernesto Inoa

Thomas M Sopko

Amir Saad

Sam Han

A work machine includes a frame, a traction system supporting the frame, a power source mounted on the frame, a switched reluctance motor, an inverter configured to control power to the motor from a power source, and a controller. The controller is configured to receive a signal indicating a desired torque and determine if the desired torque is between an upper threshold and a lower threshold. If the desired torque is between the upper threshold and the lower threshold, pulse width modulation is used to produce a PWM adjusted torque command, and the motor is commanded based on the PWM adjusted torque command. The PWM adjusted torque command is configured to cycle between the upper threshold and the lower threshold to produce the desired torque.

System and method of overcoming a dead-band in a switched reluctance motor

Power based self-sensing of a rotor position of an SR motor at mid to high speeds and low torque is achieved by an SR motor control system by comparing the motor power to an injection maximum power. A position current pulse is injected to a stator pole in response to the motor power being less than the injection maximum power. An actual stator current created by the position current pulse is compared to an estimated stator current, and a stored estimated rotor position in a memory is updated to a new estimated rotor position if the actual stator current is not equal to the estimated stator current.

Power based pulse injection control for SR self sensing

A system and method for torque compensation in a switched reluctance (SR) machine disposed on a machine is disclosed. The system may comprise a SR machine, an inverter and a controller. The controller is in operable communication with the inverter and is configured to determine a commanded main current associated with energization by a main current of a first portion of the plurality of windings for a controlling phase, and determine a commanded parasitic current associated with energization by a parasitic current of a second portion of the windings in a non-controlling phase. The controller is further configured to determine an offset current based on the commanded parasitic current, and determine a target current based on a first sum of the commanded main current and the offset current, and command the inverter to actuate the target current in the first portion of the windings during the controlling phase.

Switched reluctance self sensing active pulse torque compensation

A control system that includes a converter circuit and a control device is disclosed. The converter circuit may be configured to control a phase current of a switched reluctance machine. The control device may be configured to determine an estimated flux based on a bus voltage, a phase voltage, and a mutual voltage. The control device may be configured to determine a flux threshold based on the phase current, and determine a first limit and a second limit relative to the flux threshold. The first limit and the second limit may be scaled relative to the flux threshold based on one or more of the target speed, the load demand, or the bus voltage. The control device may be configured to compare the estimated flux with the first limit, and reset the estimated flux to the second limit based on determining that the estimated flux satisfies the first limit.

Modified flux observer for switched reluctance machines

A device may receive a current measurement of a motor identifying a plurality of component currents associated with a plurality of phases. The device may determine a position estimate for the motor based on the plurality of component currents associated with the plurality of phases. The device may control the motor based on the plurality of component currents.

Switched reluctance motor control system

An electrical inverter may include a plurality of phase modules to provide a plurality of phase outputs. Two or more of the plurality of phase modules may share a common insulated-gate bipolar transistor.

Inverter topology

A method for determining rotor position of a switched reluctance (SR) machine having a rotor and a stator is provided. The method may include injecting a test pulse into one or more idle phases of the SR machine, determining a decoupled flux value based at least partially on a total flux value corresponding to the test pulse and a mutual flux value, and determining the rotor position based at least partially on the decoupled flux value.

Sensorless control of switched reluctance machines for low speeds and standstill

A control system is provided for an electric machine having a rotor and a stator. The control system has a converter circuit in electrical communication with the stator and a controller in electrical communication with the converter circuit. The controller is configured to receive a first signal indicating a torque applied to or output by the rotor and receive a second signal indicating a rotational speed of the rotor. The controller is also configured to determine at least one characteristic of a pulse signal based on at least one of the first or second signal. The controller is also configured to inject the pulse signal into one or more phases of the stator via the converter circuit according to the determined at least one characteristic. The controller is also configured to determine a position of the rotor based on the injected pulse signal.

Adjustable pulse injection in electric machine control

A system and method for estimating a position and a speed of a rotor of a Switched Reluctance (SR) machine is provided. The SR machine comprises the rotor, a stator and at least one winding. The method includes generating a diagnostic pulse having a trapezoidal shape. The method further includes injecting a diagnostic pulse into the at least one winding of the SR machine. The method further includes measuring an actual stator current flowing through the at least one winding of the SR machine. The method further includes computing an estimated stator current flowing through the at least one winding using observer-based estimation technique. The estimated stator current is compared with the actual stator current to compute an error signal. At least one of the position and the speed of the rotor is estimated based on the error signal.

Pulse injection current pattern for rotor position estimation

A control system for a switched reluctance (SR) machine having a rotor and a stator is provided. The control system may include a converter circuit in electrical communication between the stator and a common bus, and a controller configured to monitor a bus voltage of the converter circuit and a phase current of the SR machine. The controller may be configured to determine a phase voltage based on one or more of main pulses and any diagnostic pulses, determine an estimated flux based on the phase voltage and an associated mutual voltage, determine a rotor position based at least partially on the estimated flux, and control the SR machine based on the rotor position and a desired torque.

Sensorless control of switched reluctance machines

A control system for a multi-phase switched reluctance (SR) machine, having at least two phases, is disclosed. The control system may include a converter circuit and a controller. The controller may include a phase voltage estimator module configured to determine a first phase voltage and a second phase voltage associated with a second phase second phase for the SR machine. The controller may further include a flux estimator module configured to determine first and second estimated fluxes, the first estimated flux associated with the first phase and based on the first phase voltage and an associated first mutual voltage and the second estimated flux the second estimated flux associated with the second phase and based on the second phase voltage and an associated second mutual voltage, and a position observer module configured to determine a rotor position based at least partially on the first estimated flux, the second mutual flux.

Flux estimator for switched reluctance machines

A method of controlling speed of an electric machine having a rotor and a stator is provided. The method may comprise the steps of monitoring a desired speed and a measured speed of the rotor, generating a torque command based on the desired speed and the measured speed, and controlling phase current to the stator based on a hybrid closed loop analysis of the torque command, the measured speed and an estimated position of the rotor. The estimated rotor position may be derived at least partially from the desired speed.

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Dunlap, IL, United States of America

James Michael Thorne