Control method for reducing torque ripple in switched reluctance motors
View Patent ↗A method of controlling torque ripple in a switched reluctance motor (SRM) includes splitting each phase winding of the SRM into an AC winding and a DC winding. The AC winding of each phase winding is excited with symmetrically displaced sinusoidal currents that may be projected into a reference frame that moves synchronously with the SRM rotor.
1. A method of controlling torque ripple in a switched reluctance motor, the method comprising:
splitting each phase winding of a switched reluctance motor (SRM) into an AC winding and a DC winding;
exciting the AC winding of each phase winding with symmetrically displaced sinusoidal currents; exciting the DC winding of all phase windings with a varying DC current based on spatially varying magnetic properties of the SRM; and
calculating the spatially varying magnetic properties of the SRM, wherein the spatially varying magnetic properties of the SRM are represented as
f (δ)=1+ k 3 [sin(3δ+γ)+tan(γ)cos(3δ+γ)]+ k 6 [sin(6δ+γ)+tan(γ)cos(6δ+γ)],
wherein δ is angular degrees (position), k 3 and k 6 are constants, and γ is a phase angle.
2. The method of controlling torque ripple in a switched reluctance motor according to claim 1 , wherein the varying DC current is represented as i o =√{square root over (3)} If (δ), wherein I is a nominal DC current.
3. The method of controlling torque ripple in a switched reluctance motor according to claim 1 , wherein exciting the AC winding of each phase winding with sinusoidal currents comprises projecting the phase currents into a reference frame that moves synchronously with the SRM rotor.
4. The method of controlling torque ripple in a switched reluctance motor according to claim 3 , further comprising calculating the spatially varying magnetic properties of the SRM, wherein the spatially varying magnetic properties of the SRM are represented as
f (δ)=1+ k 3 [sin(3δ+γ)+tan(γ)cos(3δ+γ)]+ k 6 [sin(6δ+γ)+tan(γ)cos(6δ+γ)],
wherein δ is angular degrees (position), k 3 and k 6 are constants, and γ is a phase angle.
5. The method of controlling torque ripple in a switched reluctance motor according to claim 4 , wherein the varying DC current is represented as i o =√{square root over (3)} If (δ), wherein I is a nominal DC current.
6. A method of controlling torque ripple in a switched reluctance motor, the method comprising:
splitting each phase winding of a switched reluctance motor (SRM) into an AC winding and a DC winding; and
exciting the AC winding of each phase winding with symmetrically displaced sinusoidal currents that are projected into a reference frame the moves synchronously with the SRM rotor, wherein the reference frame is based on spatially varying magnetic properties of the SRM.
7. The method of controlling torque ripple in a switched reluctance motor according to claim 6 , further comprising calculating the spatially varying magnetic properties of the SRM, wherein the spatially varying magnetic properties of the SRM are represented as
f (δ)=1+ k 3 [sin(3δ+γ)+tan(γ)cos(3δ+γ)]+ k 6 [sin(6δ+γ)+tan(γ)cos(6δ+γ)],
wherein δ is angular degrees (position), k 3 and k 6 are constants, and γ is a phase angle.
8. The method of controlling torque ripple in a switched reluctance motor according to claim 7 , further comprising exciting the DC winding of each phase winding with a varying DC current, wherein the varying DC current is represented as i o =√{square root over (3)} If (δ), wherein I is a nominal DC current.
9. A method of controlling torque ripple in a switched reluctance motor, the method comprising:
splitting each phase winding of a switched reluctance motor (SRM) into an AC winding and a DC winding;
exciting the DC winding of all phase windings with a varying DC current based on spatially varying magnetic properties of the SRM;
exciting the AC winding of each phase winding with symmetrically displaced sinusoidal currents that vary in response to a rotor position; and
calculating the spatially varying magnetic properties of the SRM, wherein the spatially varying magnetic properties of the SRM are represented as
f (δ)=1+ k 3 [sin(3δ+γ)+tan(γ)cos(3δ+γ)]+ k 6 [sin(6δ+γ)+tan(γ)cos(6δ+γ)],
wherein δ is angular degrees (position), k 3 and k 6 are constants, and γ is a phase angle.
10. The method of controlling torque ripple in a switched reluctance motor according to claim 9 , wherein the varying DC current is represented as i o =√{square root over (3)} If (δ), wherein I is a nominal DC current.
11. A method of controlling torque ripple in a switched reluctance motor, the method comprising:
splitting each phase winding of a switched reluctance motor (SRM) into an AC winding and a DC winding;
exciting the AC winding of each phase winding with symmetrically displaced sinusoidal currents;
exciting the DC winding of all phase windings with a varying DC current based on spatially varying magnetic properties of the SRM, wherein exciting the AC winding of each phase winding with sinusoidal currents comprises projecting the phase currents into a reference frame that moves synchronously with the SRM rotor.
12. The method of controlling torque ripple in a switched reluctance motor of claim 11 , further comprising calculating the spatially varying magnetic properties of the SRM, wherein the spatially varying magnetic properties of the SRM are represented as
f (δ)=1+ k 3 [sin(3δ+γ)+tan(γ)cos(3δ+γ)]+ k 6 [sin(6δ+γ)+tan(γ)cos(6δ+γ)],
wherein δ is angular degrees (position), k 3 and k 6 are constants, and γ is a phase angle.
13. The method of controlling torque ripple in a switched reluctance motor of claim 12 , wherein the varying DC current is represented as i o =√{square root over (3)} If (δ), wherein I is a nominal DC current.