Active filter for single phase charging using a switch-mode converter

Patent metadata

Field	Value
Publication number	US-12027969-B2
Application number	US-201917287428-A
Country	US
Kind code	B2
Filing date	Oct 23, 2019
Priority date	Nov 2, 2018
Publication date	Jul 2, 2024
Grant date	Jul 2, 2024

Abstract

A converter for electrical connection to a three-phase electrical grid and a single-phase electrical grid is provided. The converter includes three DAB modules, each for converting a respective alternating current of a three-phase electrical grid. When connected to a single-phase electrical grid, the third DAB module is bi-directional such that it is operable to filter the power output of the first and second DAB modules. The converter further includes a filter capacitor in electrical communication with the third DAB module through a relay, wherein the relay is responsive to a controller to couple the third DAB module to the filter capacitor when the single-phase electrical grid is detected and to couple the third DAB module to a grid rectifier when the three-phase electrical grid is detected.

First claim

The invention claimed is:

1. An on-board charger for a vehicle comprising:
a first switch-mode converter being operable to convert a first rectified voltage into a first DC component;
a second switch-mode converter being operable to convert a second rectified voltage into a second DC component;
a third switch-mode converter being operable to convert a third rectified voltage into a third DC component, the third switch-mode converter being bidirectional such that the third switch-mode converter is operable as an active filter to remove harmonics from a DC output of the first and second switch-mode converters when coupled to a single-phase electrical grid, wherein the third switch-mode converter is a dual active bridge converter including a primary-side full bridge, an isolation transformer, and a secondary-side full bridge;
a first rectifier, a second rectifier, and a third rectifier electrically coupled in series with the first switch-mode converter, the second switch-mode converter, and the third switch-mode converter, respectively; and
a filter capacitor selectively coupled between the third rectifier and the primary-side full bridge of the third switch-mode converter via a relay, wherein the relay is configured to alternatively couple the primary-side full bridge of the third switch-mode converter to either of the third rectifier and the filter capacitor, and wherein the filter capacitor draws power from the DC output through the third switch-mode converter if the DC output is greater than a power reference and supplies power to the DC output through the third switch-mode converter if the DC output is less than the power reference.

2. The on-board charger of claim 1 wherein each of the first and second switch-mode converters includes a dual-active-bridge topology.

3. The on-board charger of claim 1 wherein the first rectifier, the second rectifier, and the third rectifier each include a full bridge topology.

4. The on-board charger of claim 1 further including a controller to detect a single-phase AC input voltage and a three-phase AC input voltage and to control operation of the relay.

5. The on-board charger of claim 4 wherein each of the first, second, and third switch-mode converters provide unity power factor when coupled to the three-phase AC input voltage.

6. The on-board charger of claim 4 wherein the third switch-mode converter is operated 180° out of phase relative to the first and second switch-mode converters when the single-phase AC input voltage is detected by the controller.

7. The on-board charger of claim 4 further including a voltage sensor across the filter capacitor, the voltage sensor being coupled to the controller.

8. The on-board charger of claim 1 wherein the power reference is selected such that the third switch-mode converter destructively interferes with the harmonics of the DC output.

9. A method for converting an AC input voltage into a DC output voltage comprising:
providing an on-board charger including a first rectifier, a second rectifier, and a third rectifier electrically coupled in series with a first switch-mode converter, a second switch-mode converter, and a third switch-mode converter, respectively, wherein the third switch-mode converter is a dual active bridge converter including a primary-side full bridge, an isolation transformer, and a secondary-side full bridge;
in response to a three-phase AC input being detected at the on-board charger, operating the first rectifier and the first switch-mode converter to convert a first phase of the AC input into a first DC component, operating the second rectifier and the second switch-mode converter to convert a second phase of the AC input into a second DC component, and operating the third rectifier and the third switch-mode converter to convert a third phase of the AC input into a third DC component; and
in response to a single-phase AC input being detected at the on-board charger, filtering a DC output of at least one of the first and second switch-mode converters through the third switch-mode converter to reduce harmonics in the DC output, wherein filtering the DC output includes de-coupling the third switch-mode converter from the third rectifier and coupling an input stage of the third switch-mode converter to a filter capacitor via a relay, the filter capacitor being coupled between the third rectifier and the primary-side full bridge of the third switch-mode converter, wherein the relay is configured to alternatively couple the primary-side full bridge of the third switch-mode converter to either of the third rectifier and the filter capacitor, such that the filter capacitor draws power from the DC output if the DC output is greater than a power reference and supplies power to the DC output if the DC output is less than the power reference.

10. The method of claim 9 wherein the first rectifier, the second rectifier, and the third rectifier each include a full bridge topology.

11. The method of claim 9 wherein the first switch-mode converter and the second switch-mode converter each include a dual-active-bridge topology.

12. The method of claim 9 wherein the filter capacitor includes a capacitor bank.

13. The method of claim 9 further including coupling the DC output of the on-board charger to a vehicle battery.

14. The method of claim 9 further including coupling the filter capacitor to a DC output of the on-board charger through first and second switches when a three-phase AC input is detected to reduce current ripple in the DC output of the on-board charger.

15. The method of claim 14 further including decoupling the filter capacitor from the DC output of the on-board charger through the first and second switches when a single-phase AC input is detected.

Assignees

• Hella Gmbh & Co Kgaa

Inventors

• Brown Alan Wayne
• Johnson Philip Michael

Classifications

• H02J4/25

  for transfer of electric power between AC and DC networks, e.g. for supplying the DC section within a load from an AC mains system · CPC title

• H02M7/219

  in a bridge configuration · CPC title

• H02M3/33584

  Bidirectional converters · CPC title

• H02M1/44

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

• H02M1/4216

  operating from a three-phase input voltage (H02M1/4233 takes precedence) · CPC title