Method to estimate power dissipation of an inverter
AssigneeDelphi Technologies, Inc.
InventorRONALD J. KREFTA
Life of this patent
Estimating the term…
Abstract
A method to estimate power dissipation of an inverter configured to control electric energy to an electric machine. The method can estimate both conductive power losses and switched power losses of a transistor or a diode in a power switch or driver stage of the inverter. The estimation includes applying a correction factor (CF) to power dissipation calculations if the modulation index of the inverter is greater than a threshold indicating that the inverter is being over-driven or operated in a non-linear region.
Claims18
A method to estimate power dissipation of an inverter configured to control electric energy to an electric machine, said power dissipation comprising conductive power losses and switched power losses, said method comprising:
- determining a switched transistor power (PSQ) of a transistor, wherein the PSQ is based on a modulation frequency (FM), a peak transistor current (IPQ) of current through the transistor, a rail-to-rail inverter supply voltage (VS), and a transistor switching energy (ESQ) of the transistor for each modulation cycle;
- determining a modulation index (MI) of the invertor;
- determining a power factor (PF) of the electric machine;
- determining a correction factor (CF) for the PSQ, wherein the CF is set to one (1) if the MI is not greater than a threshold, and the CF is based on the MI and the PF if the MI is greater than the threshold;
- and
- estimating power dissipation of the transistor based on the PSQ and the CF.
A method to estimate power dissipation of an inverter configured to control electric energy to an electric machine, said power dissipation comprising conductive power losses and switched power losses, said method comprising:
- determining a switched diode power (PSD) of a diode based on a modulation frequency (FM), a peak diode current (IPD) of current through the diode, a rail-to-rail inverter supply voltage (VS), and a diode reverse-recovery energy (ERD) of the diode for each modulation cycle;
- determining a modulation index (MI) of the invertor;
- determining a power factor (PF) of the electric machine;
- determining a correction factor (CF) for the PSD, wherein the CF is set to one (1) if the MI is not greater than a threshold, and the CF is based on the MI and the PF if the MI is greater than the threshold;
- and
- estimating power dissipation of the diode based on the PSD and the CF.
Dependencies are inferred from the claim text.