Ford Global Technolgoies, LLC

Chang-jiang Wang

Michael W Degner

William Reynolds

Daniel Richard Luedtke

Ji Wu

Rimma Isayeva

Liwen Xu

A method for estimating torque control error at an electric machine considers the effects of current sensor error characteristics. Systems and methods can be practiced to determine the maximum sensor error that can be tolerated without causing unacceptable torque error. An example method uses sensor characteristics and machine characteristics to determine current sensing error, current control error, and torque control error. Determining the lowest sensor accuracy required for a desired torque control accuracy can facilitate the use of lower cost sensors in current-feedback controlled electric drive systems without compromising performance. Other applications can include vehicle diagnostics and torque error compensation.

Method of current sensor related torque error estimation for IPMSM e-drive system

An embedded controller in a vehicle electronics subsystem includes a signal processing circuit used to communicate with an electric machine. The signal processing circuit may be configured to receive an input signal from the electric machine and provide digital output signals to the embedded controller. The digital output signals may include Hall position and rotor position signals. Once the digital output signals are processed by a processor embedded within the controller, the processor may issue a control command to the electric machine. The processor may have memory containing software to make the processor execute the computation of the control command of the electric machine in accordance with a torque command.

Electric motor position signal synchronized operation

Systems, apparatus, and methods detect a current sensor error in an FOC electric machine system. A voltage command is monitored to detect the presence of an ac component that indicates that an error has occurred at a current sensor. For example, a sensor fault detection module can be configured to determine the deviation between an actual voltage command and an ideal voltage command to provide a complex deviation vector. By transforming the deviation vector to a reference frame rotating at the fundamental frequency of the command voltage, a dc component of the positive and negative sequences can be filtered, and their amplitudes determined. Error detection can be based on the total amplitude of the fundamental component, determined by positive and negative component amplitudes. Sensor error detection enables an FOC system to operate with two current sensors, rather than three, and provides a dedicated fault diagnostic for a current sensor.

Detection method of current sensor faults in the e-drive system by using the voltage command error

A discontinuous pulse width modulation technique is used in a controller to control an inverter that converts DC battery power to AC power to operate an electric motor, e.g., in a hybrid electric vehicle. The discontinuous pulse width modulation technique uses only one of the two zero state voltage vectors in its calculations whereas traditional pulse width modulation uses both zero state voltage vectors. The use of a single zero state voltage vector can result in one of a group of switches in the inverter remaining in a constant state during a complete duty cycle while still providing the commanded voltage vector to the electrical motor. As a result losses due to switching can be reduced.

Discontinuous pulse width modulation

Systems, methods and apparatus are presented to determine high voltage cable connectivity between an inverter module and a remote electric machine. A high frequency (HF) interlock module can be configured to inject a high frequency excitation signal that can be superimposed on inverter drive signals. High frequency current components can be determined and used to determine connectivity status. The sum and difference of positive and negative sequence component values can be compared to predetermined limitations to detect one or more open phases. An example method can include enabling a HF detection strategy under predetermined conditions. In response to an open phase detection a fault flag can be set.

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Troy, MI, United States of America

Chang-jiang Wang