# US 12,184,071 B2 · Active rectifier with phase locked varying switch frequencies

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- Number: US 12,184,071 B2
- Document ID: US12184071B2
- Status: Granted
- Kind: B2
- Application number: 18/326,361
- Filed: 2023-05-31
- Published: 2024-12-05
- Granted: 2024-12-31
- Earliest claimed: 2023-05-31
- Assignees: Hamilton Sundstrand Corporation
- Applicants: Hamilton Sundstrand Corporation
- Inventors: Huazhen H. Chai
- Web page: https://patentgrep.com/patent/US12184071B2

## CPC

- H02J 3/01: Arrangements for reducing harmonics or ripples
- H02M 1/12: Arrangements for reducing harmonics from AC input or output
- H02J 3/381: {Dispersed generators}
- H02M 7/12: using discharge tubes with control electrode or semiconductor devices with control electrode
- H02J 2105/32: {for aircrafts}
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)

## Abstract

A power distribution system includes a variable frequency alternating current (AC) generator, an active rectifier electrically connected to the variable frequency AC generator such that AC power output from the variable frequency AC generator is rectified by the active rectifier, and a switching controller configured to detect a fundamental frequency of the AC power output and lock an active switch rate of the active rectifier to an integer multiple of the fundamental frequency.

## Claims

### Claim 1

A power distribution system comprising:
a variable frequency alternating current (AC) generator;
an active rectifier electrically connected to the variable frequency AC generator such that AC power output from the variable frequency AC generator is rectified by the active rectifier; and
a switching controller configured to detect a fundamental frequency of the AC power output and lock an active switch rate of the active rectifier to an integer multiple of the fundamental frequency.

### Claim 2 (depends on 1)

The power distribution system of claim 1, wherein the variable frequency AC generator is a gas turbine engine generator.

### Claim 3 (depends on 2)

The power distribution system of claim 2, wherein the fundamental frequency is in the range of 360 Hz to 800 Hz.

### Claim 4 (depends on 1)

The power distribution system of claim 1, wherein the active switching rate of the active rectifier is one of 15 times the fundamental frequency, 21 times the fundamental frequency, and 27 times the fundamental frequency.

### Claim 5 (depends on 4)

The power distribution system of claim 4, wherein the active switching rate of the active rectifier is 21 times the fundamental frequency.

### Claim 6 (depends on 4)

The power distribution system of claim 4, wherein the active switching rate of the active rectifier is 15 times the fundamental frequency.

### Claim 7 (depends on 4)

The power distribution system of claim 4, wherein the active switching rate of the active rectifier is 27 times the fundamental frequency.

### Claim 8 (depends on 1)

The power distribution system of claim 1, wherein the switching controller is a dedicated active rectifier controller.

### Claim 9 (depends on 1)

The power distribution system of claim 1, wherein the switching controller is a component of a general purpose aircraft controller.

### Claim 10

A method for reducing attenuation requirements in an active rectifier comprising:
identifying a fundamental frequency of an alternating current (AC) power received by the active rectifier and setting a switching rate to of the active rectifier to an odd number integer multiple of the fundamental frequency using a controller.

### Claim 11 (depends on 10)

The method of claim 10, wherein the switching rate of the active rectifier is one of 15 times the fundamental frequency, 21 times the fundamental frequency, and 27 times the fundamental frequency.

### Claim 12 (depends on 11)

The method of claim 11, wherein the switching rate of the active rectifier is 21 times the fundamental frequency.

### Claim 13 (depends on 11)

The method of claim 11, wherein the switching rate of the active rectifier is 15 times the fundamental frequency.

### Claim 14 (depends on 11)

The method of claim 11, wherein the switching rate of the active rectifier is 27 times the fundamental frequency.

### Claim 15 (depends on 10)

The method of claim 10, wherein the AC power is generated by a variable frequency generator and wherein the fundamental frequency of the AC power varies across operation of the variable frequency generator.

### Claim 16 (depends on 15)

The method of claim 15, wherein the fundamental frequency of the AC power varies across the range of 360 Hz to 800 Hz.

### Claim 17 (depends on 15)

The method of claim 15, wherein the variable frequency generator is a gas turbine engine generator.

### Claim 18

An aircraft power distribution system comprising:
a gas turbine engine including a variable frequency generator;
an active rectifier electrically connected to the variable frequency generator and configured to rectify power received from the variable frequency generator; and
a switching controller coupled to the active rectifier and configured to set a switching rate of the active rectifier to a whole number integer multiple of a fundamental frequency of the power.

### Claim 19 (depends on 18)

The aircraft power distribution system of claim 18, wherein the fundamental frequency of the power varies in the range of 360 Hz to 800 Hz, and wherein the whole number integer is one of 15, 21 and 27.

### Claim 20 (depends on 18)

The aircraft power distribution system of claim 18, wherein the fundamental frequency varies across a single operation.