Motor phase current measurement using a single DC bus shunt sensor
AssigneeDelphi Technologies, Inc.
InventorsSayeed A. Mir, Paul M. Fisher, Daniel W. Shafer, Samuel J. Underwood
Life of this patent
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Abstract
A method and system for obtaining motor current measurements from a DC bus current of an inverter that drives a pulse width modulated electric machine is disclosed. The method may include sensing a DC bus current in a sensor located on a bus of an inverter; sampling the DC bus current via an analog to digital converter wherein the sampling is controlled by sampling timing that is based on a pulse width modulation timing of the inverter; and determining three AC phase currents of the motor from the sampled DC bus current.
Claims17
A method for obtaining motor current measurements from a DC bus current of an inverter that drives a pulse width modulated electric machine comprising:
- sensing a DC bus current in a sensor located on a bus of an inverter;
- sampling the DC bus current via an analog to digital converter wherein the sampling is controlled by sampling timing that is based on a pulse width modulation timing of the inverter, and further wherein the sampling comprises a first current measurement timed to occur at a point where an average of two sine wave reference signals intersects with a timer signal that is coordinated with the pulse width modulation timing of the inverter;
- and
- determining three AC phase currents of the motor from the sampled DC bus current.
An arrangement for obtaining motor current measurements from a DC bus current of an inverter that drives a pulse width modulated electric machine, comprising:
- a current sensor located on a DC inverter bus for sensing a DC bus current of an inverter;
- an analog to digital converter for sampling the DC bus current obtained from the current sensor and for converting DC bus current samples to digital format for processing;
- at least one timer for controlling the analog to digital converter in order to control the sampling wherein the timer is coordinated with a pulse width modulation timing of the inverter, and wherein the sampling comprises a first current measurement timed to occur at a point where an average of two sine wave reference signals intersects with a timer signal that is coordinated with the pulse width modulation timing of the inverter;
- and
- a control processor for processing the DC bus current samples and for determining AC phase currents from the DC bus current wherein the processor also controls the pulse width modulation timing of the inverter.
A system for measuring current in a sinusoidally excited permanent magnet electric machine using only one current sensor comprising:
- providing a controller for controlling pulse width modulation and duty cycles of an inverter that creates AC phase currents which drive a sinusoidally excited permanent magnet electric machine;
- providing one and only one current sensor on a DC inverter bus of the inverter;
- sensing a DC bus current via the sensor;
- providing an analog to digital converter for sampling the DC bus current via the analog to digital converter;
- sampling the DC bus current in the analog to digital converter wherein the sampling is controlled by sampling timing that is based on a pulse width modulation timing of the inverter, and further wherein the sampling comprises a first current measurement timed to occur at a point where an average of two sine wave reference signals intersects with a timer signal that is coordinated with the pulse width modulation timing of the inverter;
- and
- determining the AC phase currents of the motor from the sampled DC bus current.
Dependencies are inferred from the claim text.