Ford Global Technolgoies, LLC

Papiya Bagchi

Monty J Anderson

William Robert Brown

Baoming Ge

Benjamin A Tabatowski-Bush

Joseph Sherman Kimmel

Jogendra Singh Thongam

An electric drive system includes an inverter and a variable voltage converter. An inductor associated with the variable voltage converter is subject to temperature limits. Dynamic models are used to estimate the temperature of the inductor. Inputs to these dynamics models include DC current, DC voltage, Battery Voltage, oil pump speed, motor speed, and sump temperature. Empirical constants in the models are set based on vehicle testing.

Dynamic models for inductor temperature

A controller reduces power output of an inverter of an electric drive system while a sensed temperature associated with the inverter, a sensed current output of the inverter, and parameter values of a busbar of the inverter are indicative of a predicted temperature of the busbar being greater than a threshold to maintain busbar temperature lower than the threshold. The current output of the inverter may be outputted over the busbar. The parameter values are obtainable from a thermal model of the busbar. The thermal model may be derived from testing a test version of the inverter under different drive cycles in which for each a set of information is recorded including a sensed temperature of the test inverter, a sensed current output of the test inverter, and a sensed temperature of the busbar of the test inverter.

Method and system for controlling electric drive system according to predicted temperature of inverter busbar

An electric drive system includes a power electronics module (PEM) having a DC-link capacitor and an inverter. A controller reduces power output of the inverter while a sensed temperature of an inverter power switch, a sensed current of the PEM, such as a sensed ripple current of the DC-link capacitor, and parameter values of the DC-link capacitor are indicative of a predicted temperature of the capacitor being greater than a threshold to maintain capacitor temperature lower than the threshold. The parameter values are obtainable from a thermal model of the DC-link capacitor. The thermal model may be derived from testing a test version of the PEM under different drive cycles in which for each drive cycle a set of information is recorded including a sensed temperature of the inverter power switch test version, a current of the PEM test version, and a sensed temperature of the DC-link capacitor test version.

Method and system for controlling electric drive system according to predicted temperature of DC-link capacitor to prevent overheating

An electrified vehicle has first and second DC buses and a chassis ground. A leakage detector has a detector switch and detector resistor in series between the first bus and chassis ground. A voltage measured across the detector resistor is proportional to a leakage resistance between the second bus and chassis. An inverter has a plurality of phase legs, each having first and second phase switches coupled between the buses. An AC traction motor has phases coupled to the phase legs. An inverter control circuit receives data messages having a predetermined latency period from the detector identifying a measured leakage resistance. Switching events are detected during which a phase switch is closed for a duration greater than the latency period. An electrical short is indicated if the measured leakage resistance in a data message received during a detected switching event is less than a predetermined threshold.

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Northville, MI, United States of America

Papiya Bagchi