Torque ripple and noise reduction by avoiding mechanical resonance for a brushless DC machine
First Claim
Patent Images
1. A method of reducing torque ripple and noise for an brushless DC machine comprising:
- determining a control frequency for said electric machine, said control frequency indicative of an existing current command to and a rotational velocity of said electric machine;
multiplying said control frequency by a selected multiple and forming a modulating signal responsive thereto;
formulating a modified command profile;
correlating and synchronizing said modified command profile with said existing current command and a rotor position for said electric machine; and
generating a modulated current command to said electric machine.
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Abstract
A method of reducing torque ripple and noise for an brushless DC machine comprising: determining a control frequency for the electric machine, the control frequency indicative of an existing current command to and a rotational velocity of the electric machine; multiplying the control frequency by a selected multiple and forming a modulating signal responsive thereto; and formulating a modified command profile. The method also includes: correlating and synchronizing the modified command profile with the existing current command and a rotor position for the electric machine; and generating a modulated current command to the electric machine.
46 Citations
19 Claims
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1. A method of reducing torque ripple and noise for an brushless DC machine comprising:
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determining a control frequency for said electric machine, said control frequency indicative of an existing current command to and a rotational velocity of said electric machine;
multiplying said control frequency by a selected multiple and forming a modulating signal responsive thereto;
formulating a modified command profile;
correlating and synchronizing said modified command profile with said existing current command and a rotor position for said electric machine; and
generating a modulated current command to said electric machine. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for reducing torque ripple and noise for an electric machine comprising:
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an electric machine in operable communication with an inverter;
a position sensor in operable communication with said electric machine, said position sensor configured to detect a position of said electric machine and transmit a signal indicative thereof;
a current sensor configured to measure a current supplied to said electric machine and transmit a signal indicative thereof;
a controller in operable communication with said inverter, said position sensor, and said current sensor, said controller configured to execute a method comprising;
determining a control frequency for said electric machine, said control frequency indicative of an existing current command to, and a rotational velocity of, said electric machine;
multiplying said control frequency by a selected multiple and forming a modulating signal responsive thereto;
formulating a modified command profile;
correlating and synchronizing said modified command profile with said existing current command and a rotor position for said electric machine; and
generating a modulated current command to said electric machine. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A system for reducing torque ripple and noise for an electric machine comprising:
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a means for determining a control frequency for said electric machine, said control frequency indicative of an existing current command to and a rotational velocity of said electric machine;
a means for multiplying said control frequency by a selected multiple and forming a modulating signal responsive thereto;
a means for formulating a modified command profile;
a means for correlating and synchronizing said modified command profile with said existing current command and a rotor position for said electric machine; and
a means for generating a modulated current command to said electric machine.
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Specification