Method to improve output current harmonic distribution in a segmented drive system

Patent metadata

Field	Value
Publication number	US-10951146-B1
Application number	US-201916565098-A
Country	US
Kind code	B1
Filing date	Sep 9, 2019
Priority date	Sep 9, 2019
Publication date	Mar 16, 2021
Grant date	Mar 16, 2021

Abstract

A segmented electrical drive system comprising a DC power bus comprising a DC voltage supply and a capacitor in parallel, an inverter comprising a plurality of inverter segments, a motor including a plurality of stator winding segments each connected to an inverter segment, and a controller. The controller receives a control signal and sends a switching signal to each of the inverter segments, wherein the switching signal is based on a discontinuous space vector pulse width modulation (DSVPWM) scheme for a segmented inverter. The DSVPWM scheme includes a set of reverse sawtooth carrier signals that are at an optimal phase shift angle with respect to each other.

First claim

What is claimed is:

1. A segmented electrical drive system comprising:
a DC power bus comprising a DC voltage supply and a capacitor connected in parallel with the DC voltage supply;
an inverter comprising a plurality of inverter segments, wherein each inverter segment includes a plurality of inverter switch pairs each connected in parallel with the DC power bus;
a motor connected to the inverter, wherein the motor includes a plurality of stator winding segments, wherein a stator winding segment in the plurality of stator winding segments is assigned to each inverter segment, and wherein each stator winding segment includes at least one stator winding for each inverter switch pair in the plurality of inverter switch pairs of the associated inverter segment; and
a controller, wherein the controller receives a control signal and sends a switching signal to each of the inverter segments, wherein the control signal corresponds with a desired stator magnetic field vector, wherein the switching signal sent to each inverter segment corresponds with a space vector pulse width modulation (SVPWM) used to produce the desired stator magnetic field vector by means of combining a plurality of base vectors produced by the plurality of stator winding segments, wherein each base vector is produced by an inverter switch pair's activity to generate a pulse width modulated signal according to a SVPWM schedule through its corresponding at least one stator winding, and wherein at least one stator winding in the plurality of stator winding segments is not driven by any inverter switch pair activity from its corresponding inverter switch pair during a given cycle of the SVPWM schedule;
wherein the switching signal to produce the pulse width modulated signal of each inverter switch pair is determined by comparing a carrier signal to a reference signal.

2. The drive system of claim 1 , wherein the carrier signals associated with each of the plurality of inverter switch pairs are sawtooth carrier signals.

3. The drive system of claim 1 , wherein the carrier signals associated with each of the plurality of inverter switch pairs are reverse sawtooth carrier signals.

4. The drive system of claim 1 , wherein the carrier signals and reference signals associated with an inverter segment are at an optimal phase shift angle with respect to the carrier signals and pulse width modulated signals associated with each other inverter segment in the plurality of inverter segments.

5. The drive system of claim 4 , wherein the optimal phase shift angle is determined by the use of a mathematical model of the inverter.

6. The drive system of claim 4 , wherein the optimal phase shift angle is a fixed value during operation of the drive system.

7. The drive system of claim 4 , wherein the implementation of an optimal phase shift angle reduces a ripple current of the capacitor.

8. A vehicle including a segmented electrical drive system, the drive system comprising:
a DC power bus comprising a DC voltage supply and a capacitor connected in parallel with the DC voltage supply;
an inverter comprising a plurality of inverter segments, wherein each inverter segment includes a plurality of inverter switch pairs each connected in parallel with the DC power bus;
a motor connected to the inverter, wherein the motor includes a plurality of stator winding segments, wherein a stator winding segment in the plurality of stator winding segments is assigned to each inverter segment, and wherein each stator winding segment includes at least one stator winding for each inverter switch pair in the plurality of inverter switch pairs of the associated inverter segment; and
a controller, wherein the controller receives a control signal and sends a switching signal to each of the inverter segments, wherein the control signal corresponds with a desired stator magnetic field vector, wherein the switching signal sent to each inverter segment corresponds with a space vector pulse width modulation (SVPWM) used to produce the desired stator magnetic field vector by means of combining a plurality of base vectors produced by the plurality of stator winding segments, wherein each base vector is produced by an inverter switch pair's activity to generate a pulse width modulated signal according to a SVPWM schedule through its corresponding at least one stator winding, and wherein at least one stator winding in the plurality of stator winding segments is not driven by any inverter switch pair activity from its corresponding inverter switch pair during a given cycle of the SVPWM schedule;
wherein the switching signal to produce the pulse width modulated signal of each inverter switch pair is determined by comparing a carrier signal to a reference signal.

9. The vehicle of claim 8 , wherein the carrier signals associated with each of the plurality of inverter switch pairs are sawtooth carrier signals.

10. The vehicle of claim 8 , wherein the carrier signals associated with each of the plurality of inverter switch pairs are reverse sawtooth carrier signals.

11. The vehicle of claim 8 , wherein the carrier signals and reference signals associated with an inverter segment are at an optimal phase shift angle with respect to the carrier signals and pulse width modulated signals associated with each other inverter segment in the plurality of inverter segments.

12. The vehicle of claim 11 , wherein the optimal phase shift angle is determined by the use of a mathematical model of the inverter.

13. The vehicle of claim 11 , wherein the optimal phase shift angle is a fixed value during operation of the drive system.

14. The vehicle of claim 11 , wherein the implementation of an optimal phase shift angle reduces a ripple current of the capacitor.

15. A method of operating a segmented electrical drive system, the drive system comprising:
a DC power bus comprising a DC voltage supply and a capacitor connected in parallel with the DC voltage supply;
an inverter comprising a plurality of inverter segments, wherein each inverter segment includes a plurality of inverter switch pairs each connected in parallel with the DC power bus;
a motor connected to the inverter, wherein the motor includes a plurality of stator winding segments, wherein a stator winding segment in the plurality of stator winding segments is assigned to each inverter segment, and wherein each stator winding segment includes at least one stator winding for each inverter switch pair in the plurality of inverter switch pairs of the associated inverter segment; and
a controller, wherein the controller receives a control signal and sends a switching signal to each of the inverter segments, wherein the control signal corresponds with a desired stator magnetic field vector, wherein the switching signal sent to each inverter segment corresponds with a space vector pulse width modulation (SVPWM) used to produce the desired stator magnetic field vector by means of combining a plurality of base vectors produced by the plurality of stator winding segments, wherein each base vector is produced by an inverter switch pair's activity to generate a pulse width modulated signal according to a SVPWM schedule through its corresponding at least one stator winding, and wherein at least one stator winding in the plurality of stator winding segments is not driven by any inverter switch pair activity from its corresponding inverter switch pair during a given cycle of the SVPWM schedule;
wherein the switching signal to produce the pulse width modulated signal of each inverter switch pair is determined by comparing a carrier signal to a reference signal.

Assignees

• Karma Automtoive Llc
• Karma Automotive Llc

Inventors

• Tang Lixin
• Niu Geng

Classifications

• H02P29/50

  Reduction of harmonics · CPC title

• H02P27/08

  with pulse width modulation · CPC title

• H02P21/22 Primary

  Current control, e.g. using a current control loop · CPC title

• H02P21/14

  Estimation or adaptation of machine parameters, e.g. flux, current or voltage · CPC title

• H02P21/05 Primary

  specially adapted for damping motor oscillations, e.g. for reducing hunting · CPC title