Trane International Inc.

Korwin Jay Anderson

Nathan Thomas West

David Marshall Foye

Benjamin James Sykora

Dennis Myron Beekman

Robert S Bakkestuen

Thomas Anthony Lipo

Matthew A Shepeck

William James Walters

A system includes a refrigerant compressor, an electric motor and configured to drive the refrigerant compressor, and a controller. The controller is configured to operate the compressor in a liquid clearing start mode where electrical current through the motor is prevented from exceeding a predetermined current limit for a period of time not to exceed a predetermined period of time, and is configured to operate the compressor in a run mode in response to determining the motor exceeds a predetermined speed threshold at or before expiration of the predetermined period of time, wherein the run mode does not prevent electrical current through the motor from exceeding said predetermined current limit.

Controls and operation of variable frequency drives

Operation of a variable frequency in a manner configured to avoid overheating is provided. In one form, a method includes providing a variable frequency drive that includes a switching device in thermal communication with a heat sink including a thermal mass. The method further includes operating the drive in a first mode before active cooling of the heat sink is established and a second mode following the first mode. Operation of the drive in the first mode includes operating the switching device in a first switching frequency mode, and the first switching frequency mode and the thermal mass of the heat sink are selected to provide a temperature of the switching device below a predetermined threshold before active cooling of the heat sink is established. Further embodiments, forms, features, and aspects shall become apparent from the description and drawings.

Variable frequency drive operation to avoid overheating

A system includes a refrigerant circuit including a compressor, a condenser, an expander, an electric motor configured to drive the compressor, and a controller configured to control a motor drive to drive the electric motor. The controller is configured to first evaluate whether the compressor is idle based upon a control state of the controller being configured not to operate the motor drive to drive the motor, second, in response to an affirmative evaluation that the compressor is idle, evaluate a risk of undesired or un-commanded compressor rotation based upon a combination of two or more system conditions, each of the two or more system conditions indicating the risk of undesired or un-commanded compressor rotation, and third, in response to an affirmative evaluation of the risk of undesired or un-commanded compressor rotation, control the motor drive to oppose rotation of the compressor.

Overvoltage protection apparatuses, systems and methods for variable frequency motor drives are disclosed. In an exemplary embodiment, a variable frequency motor drive system including a rectifier, a DC bus electrically coupled with the rectifier, and an inverter electrically coupled with the DC bus is provided. A protection device electrically coupled with the rectifier and configured to interrupt power supply to the system based upon fault conditions is provided. A controller is provided and configured to receive information indicative of a voltage of the DC bus, process the received information to model a condition of at least one component of the variable frequency motor drive, and control the protection device to interrupt power supply to the variable frequency motor drive if the modeled condition meets a fault criterion.

Variable frequency drive overvoltage protection

Systems and methods are used to control operation of a rotary compressor of a refrigeration system to limit or prevent movement of rotors due to axial thrust loading resulting from rapid changes in speed of the rotors of the compressor. The operational profile of the motor is controlled to maintain acceleration torque and deceleration torque within predefined limits. The acceleration torque and deceleration torque are maintained within the predefined limits by controlling the speed of the motor, or by controlling the torque applied by the motor to the rotors during acceleration or deceleration.

Axial thrust control for rotary compressors

A controller is configured to generate control signals to control a variable frequency drive coupled with a load. A simulator receives the control signals and processes the control signals. The simulator simulates a variable frequency drive and a load by generating feedback signals based on a model and the control signals. The controller receives the feedback signals from the simulator.

Dynamic simulated motor for controller testing

Variable frequency drive active harmonic mitigation controls and diagnostics are disclosed. Exemplary controls and diagnostics include operating a variable frequency drive including converting an AC input line voltage to a DC voltage, generating a motor drive signal using the DC voltage, and driving an electric motor with the motor drive signal. A harmonic mitigation signal is provided to the drive configured to at least partially mitigate harmonics during the operation of the drive. The harmonic mitigation signal is inhibited based upon presence of an error condition associated with the drive input. The inhibiting is terminated based upon the absence of the error condition. A diagnostic fault condition based upon a number of occurrences of the error condition.

Variable frequency drive active harmonic mitigation controls and diagnostics

Diagnostic and/or control methods, systems and apparatuses for variable frequency drives are disclosed. The variable frequency drive may be controlled by a controller that may conduct one or more tests or evaluations. The tests or evaluations may include determining whether a switching device in the variable frequency drive is open-circuited, short-circuited, or operating normally. The tests may include determining whether current provided at an inverter output of the variable frequency drive is within a predetermined range. An exemplary embodiment evaluates the drive for a short circuit condition, an open circuit condition, and a sensor error or failure condition, controls operation of the drive based upon these one or more evaluations, may abort operation of the drive based upon one or more evaluations, and may set a fault code indicative of the type of error encountered.

Variable frequency drive self-check

An exemplary inverter includes first, second and third legs connected in parallel to a line rail and a neutral rail. Each leg includes a first switch, a second switch, and a node between the first and second switches. The first leg further includes a voltage boosting section operable to selectively increase and decrease the voltage potential of the node of the first leg. The voltage boosting section may include a capacitor in parallel with the first and second switches. The first leg may further include a third switch in series with the voltage boosting section and between the voltage boosting section and the line rail, and a fourth switch in series with the voltage boosting section and between the voltage boosting section and the neutral rail.

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Pasadena, CA, United States of America

Korwin Jay Anderson