Impedance balancing for noise filtering in electric drive systems

Patent metadata

Field	Value
Publication number	US-11608186-B2
Application number	US-202117450045-A
Country	US
Kind code	B2
Filing date	Oct 5, 2021
Priority date	Jan 5, 2021
Publication date	Mar 21, 2023
Grant date	Mar 21, 2023

Abstract

An electric drive system including an impedance balancing noise filtering circuit is disclosed. The electric drive system includes a direct current (DC) power source configured to output DC power to an output port and an inverter configured to convert the DC power output by the DC power source into alternating current (AC) power that is provided to an input port of an AC load. The impedance balancing noise filtering circuit includes an impedance bridge electrically intermediate the output port of the DC power source and the input port of the AC load. The impedance balancing noise filtering circuit includes different sets of passive components that are positioned on both the DC-side and the AC-side of the inverter. These sets of passive components are configured to facilitate impedance balancing that reduces common-mode (CM) electromagnetic interference (EMI) emission at the output port of the DC power source.

First claim

The invention claimed is:

1. A system, comprising:
a direct current (DC) power source configured to output DC power to an output port;
an inverter including an input port and an output port, wherein the inverter is configured to convert DC power output by the DC power source into alternating current (AC) power provided to an input port of an AC load such that the AC load is driven by the AC power; and
an impedance balancing noise filtering circuit including:
a set of AC-side choke inductors electrically intermediate the output port of the inverter and the input port of the AC load;
a set of AC common mode filter capacitors electrically intermediate the input port of the AC load and ground and electrically intermediate the AC-side choke inductor and ground;
a set of DC common mode filter capacitors electrically intermediate the input port of the inverter and ground and electrically intermediate the output port of the DC power source and ground; and
an impedance bridge electrically intermediate the output port of the DC power source and the input port of the AC load.

2. The system of claim 1 , wherein the output port of the DC power source includes a positive output terminal and a negative output terminal, wherein the impedance bridge includes a Wheatstone impedance bridge including a first DC-side bridge capacitor electrically intermediate the positive output terminal of the DC power source and a DC-side bridge connection node, a second DC-side bridge capacitor intermediate the negative output terminal of the DC power source and the DC-side bridge connection node, wherein the first DC-side bridge capacitor, the DC-side bridge connection node, and the second DC-side bridge capacitor are in series between the positive output terminal of the DC power source and the negative output terminal of the DC power source, and wherein the Wheatstone impedance bridge further includes a bridge inductor electrically intermediate the DC-side bridge connection node and an intermediate bridge node, a first AC-side bridge resistor in series with a first AC-side bridge capacitor between the intermediate bridge node and a first AC-side bridge connection node, a second AC-side bridge resistor in series with a second AC-side bridge capacitor between the intermediate bridge node and a second AC-side bridge connection node, and a third AC-side bridge resistor in series with a third AC-side bridge capacitor between the intermediate bridge node and a third AC-side bridge connection node.

3. The system of claim 2 , wherein the input port of the inverter includes a positive input terminal and a negative input terminal, wherein the set of DC common mode filter capacitors includes a first DC common mode filter capacitor electrically intermediate the positive input terminal of the inverter and ground and a second DC common mode filter capacitor electrically intermediate the negative input terminal of the inverter and ground, and wherein the impedance balancing noise filtering circuit includes a set of DC-side choke inductors including a first DC-side choke inductor electrically intermediate the positive output terminal of the DC power source and the positive input terminal of the inverter and a second DC-side choke inductor electrically intermediate the negative output terminal of the DC power source and the negative input terminal of the inverter.

4. The system of claim 3 , wherein the output port of the inverter includes first, second, and third output terminals, wherein the set of AC-side choke inductors includes a first AC-side choke inductor electrically intermediate the first output terminal of the inverter and the first AC-side bridge connection node, a second AC-side choke inductor electrically intermediate the second output terminal of the inverter and the second AC-side bridge connection node, and a third AC-side choke inductor electrically intermediate a third output terminal of the inverter and the third AC-side bridge connection node, and wherein the set of AC common mode filter capacitors includes a first AC common mode filter capacitor electrically intermediate the first AC-side bridge connection node and ground, a second AC common mode filter capacitor electrically intermediate the second AC-side bridge connection node and ground, and a third AC common mode filter capacitor electrically intermediate the third AC-side bridge connection node and ground.

5. The system of claim 4 , wherein a ratio of an inductance of the bridge inductor of the Wheatstone impedance bridge and an inductance of the set of DC-side choke inductors is equal to a ratio of a capacitance of the set of AC common mode filter capacitors and a capacitance of the set of DC common mode filter capacitors for an electromagnetic interference frequency range.

6. The system of claim 1 , wherein the impedance balancing noise filtering circuit is configured to balance a common mode device parasitic impedance of the inverter and a common mode impedance of the AC load.

7. The system of claim 1 , wherein the impedance balancing noise filtering circuit is configured to introduce a common mode balancing current through the output port of the DC power source, wherein the common mode balancing current has an amplitude substantially matching an amplitude of a common mode current generated by parasitic impedances at the output port of the DC power source, and wherein the common mode balancing current has an opposite polarity of the common mode current generated by parasitic impedances at the output port of the DC power source.

8. The system of claim 1 , wherein the AC load includes an AC motor.

9. The system of claim 8 , wherein the AC load further includes a power cable intermediate the AC motor and the input port of the AC load.

10. The system of claim 9 , wherein the inverter and the impedance balancing noise filtering circuit are contained in a common enclosure, wherein the AC motor is located outside the common enclosure, wherein the impedance balancing noise filtering circuit is configured to filter AC power output by the inverter to generate filtered AC power having reduced electromagnetic interference noise measured at the output port of the DC power source, and wherein the power cable is configured to deliver the filtered AC power out of the common enclosure to the AC motor.

11. The system of claim 10 , wherein the AC motor is located in an aircraft wing, and wherein the common enclosure is located in an aircraft fuselage.

12. A method for controlling an electric drive system to drive an AC load, the method comprising:
outputting direct current (DC) power from a DC power source;
converting, via an inverter, the DC power to alternating current (AC) power;
filtering, via an impedance balancing noise filtering circuit, the AC power to generate filtered AC power, wherein the impedance balancing noise filtering circuit includes a set of AC-side choke inductors electrically intermediate an output port of the inverter and an input port of the AC load, a set of AC common mode filter capacitors electrically intermediate the input port of the AC load and ground and electrically intermediate the set of AC-side choke inductors and ground, a set of DC common mode filter capacitors electrically intermediate an input port of the inverter and ground and electrically intermediate the output port of the DC power source and ground, and an impedance bridge electrically intermediate the output port of the DC power source and the input port of the AC load; and
outputting the filtered AC power to the input port of the AC load to drive the AC load with the filtered AC power.

13. The method of claim 12 , wherein the impedance balancing noise filter

Assignees

• Boeing Co

Inventors

• Solodovnik Eugene V
• Karimi Kamiar J
• Liu Shengyi

Classifications

• H02J2105/32

  for aircrafts · CPC title

• B64D27/35

  Arrangements for on-board electric energy production, distribution, recovery or storage · CPC title

• B64D27/359

  using capacitors · CPC title

• B64D41/00 Primary

  Power installations for auxiliary purposes · CPC title

• H02M1/44

  Circuits or arrangements for compensating for electromagnetic interference in converters or inverters · CPC title