Multi-phase AC/DC converter

Patent metadata

Field	Value
Publication number	US-11923767-B2
Application number	US-202318163960-A
Country	US
Kind code	B2
Filing date	Feb 3, 2023
Priority date	May 14, 2020
Publication date	Mar 5, 2024
Grant date	Mar 5, 2024

Abstract

The present disclosure provides a three-phase AC/DC converter aiming for low input current harmonic. The converter includes an input stage for receiving a three-phase AC input voltage, an output stage for at least one load, and one or more switching conversion stages, each stage including a plurality of half bridge modules. The switches in each module operate with a substantially fixed 50% duty cycle and are connected in a specific pattern to couple a DC-link and a neutral node of the input voltage. The AC/DC converter further includes one or more controllers adapted to vary the switching frequency of the switches in the switching conversion stages based on at least one of load voltage, load current, input voltage, and DC-link voltage. The converter can also include one or more decoupling stages, such as, inductive components adapted to decouple the output stage from the switching conversion stages.

First claim

What is claimed is:

1. An AC/DC converter, comprising:
a plurality of internal terminals including positive, negative, and neutral internal terminals;
an input stage connected to the positive, negative, and neutral internal terminals and having at least three input terminals for connecting to a three-phase AC power source;
a switching stage having a plurality of modules connected in series between the positive internal terminal and the negative internal terminal, each module having two switches and a capacitor connected serially in a loop, at least one of the modules connected to the positive internal terminal, at least one of the modules connected to the negative internal terminal, and at least two of the modules connected to the neutral internal terminal;
an output stage connected to the positive internal terminal and configured to provide DC voltage to output terminals for connecting to a load; and
a controller having a plurality of control signal outputs connected to the plurality of switches and configured to generate control signals for said switches,
wherein the switch stage has (2N+2M) modules, where n and M are positive integers,
for each module the plurality of switches comprise two switches, and the two switches and the capacitor of each module are connected serially in a loop,
the module connected to the positive terminal is connected to the positive terminal by a node in the loop containing the two switches of said module,
the module connected to the negative terminal is connected to the negative terminal by a node in the loop containing the two switches of said module,
a first of the at least two modules connected to the neutral internal terminal is connected to the neutral internal terminal by a node in the loop connecting the two switches of said module, and
a second of the at least two modules connected to the neutral internal terminal is connected to the neutral internal terminal by a node in the loop connecting the two switches of said module.

2. The converter of claim 1 , wherein each of the 2n modules is paired with another of the 2n modules and each of the 2m modules is paired with another of the 2m modules, each pair having a common node that for both modules in said pair connects the capacitor of the respective module to one of the switches of the respective module.

3. The converter of claim 2 , wherein
n=1,
m=1,
the module connected to the positive terminal is paired with the first of the at least two modules connected to the neutral internal terminal, and
the module connected to the negative terminal is paired with the second of the at least two modules connected to the neutral internal terminal.

4. The converter of claim 1 , wherein the output stage comprises
a plurality of capacitors connected in series between the positive and negative internal terminals,
a transformer having a first winding and a second winding, the first winding having a first terminal and a second terminal connected to the neutral terminal;
a resonant inductor and resonant capacitor connected in series between a midpoint node in the series connected plurality of capacitors and the first terminal of the first winding of the transformer; and
a full-wave diode bridge connected to the second winding of the transformer and the output terminals.

5. The converter of claim 1 , wherein the output stage is further connected to the negative and neutral terminals.

6. The converter of claim 1 , wherein the output stage is a first output stage, the output terminals are first output terminals, and the load is a first load, the converter further comprising a second output stage connected to the negative internal terminal and configured to provide DC voltage to second output terminals for connecting to a second load.

7. The converter of claim 1 , wherein the output stage is a first output stage, the output terminals are first output terminals, and the positive and negative internal terminals are a first positive and first negative internal terminals, respectively, the converter further comprising:
a second positive internal terminal and a second negative internal terminal, wherein the input stage is further connected to said second positive and second negative internal terminals;
a second switching stage having a second plurality of modules serially connected between the second positive and second negative internal terminals; and
a second output stage connected to the first and second negative internal terminals and configured to provide DC voltage to second output terminals,
wherein the first output stage is further connected to the second positive internal terminal.

8. An AC/DC converter comprising:
input terminals for connecting to a three-phase input voltage source;
an input filter stage coupled to the input terminals and connected to a positive node, a negative node and a neutral node;
a switching stage having n half bridge modules, where n is a positive integer greater than 1, the half bridge modules connected in series between the positive and negative node, and having the neutral node connected to a series connection between the j-th and (j+1)-th half bridge modules in the series (where 1≤j≤n−1), wherein each half bridge module comprises a capacitor and two switches connected in series, and wherein the capacitor and the two switches are connected to form a loop;
an output stage connected to the positive node and configured to provide DC voltage to output terminals for connecting to a load; and
a controller configured to generate control signals on control signal outputs electrically connected to the half bridge modules,
wherein the half bridge modules have (2w+2x) modules, where w and x are positive integers,
for each half bridge module the plurality of switches comprise two switches, and the two switches and the capacitor of each half bridge module are connected serially in a loop,
the half bridge module connected to the positive node is connected to the positive node by a node in the loop containing the two switches of said half bridge module,
the half bridge module connected to the negative node is connected to the negative node by a node in the loop containing the two switches of said half bridge module,
a first of the at least two half bridge modules connected to the neutral node is connected to the neutral node by a node in the loop connecting the two switches of said half bridge module, and
a second of the at least two half bridge modules connected to the neutral node is connected to the neutral node by a node in the loop connecting the two switches of said half bridge module.

9. The converter of claim 8 , wherein a first node connecting the capacitor to one of the switches of an i-th half bridge module is electrically connected to a second node connecting the two switches of the (i+1)-th half bridge module for 1≤i≤n−1.

10. The converter of claim 8 , wherein n is a positive even integer and wherein each half bridge module is paired with another of the half bridge modules forming a series half bridge module, each series half bridge module having a common node that for both half bridge modules in said series half bridge module connects the capacitor of the respective half bridge module to one of the switches of the respective half bridge module.

11. The converter of claim 10 , wherein
each half bridge module having a switch connecting node connecting the switches of said half bridge module,
the paired half bridge modules forming each series half bridge module are a top half bridge module and a bottom half bridge module, and
the series half bridge modules are connected in series to one another by connecting, for each k (for 2≤k≤n/2) the switch connecting node

Assignees

• Delta Electronics Inc

Inventors

• Zhang Chi
• Shen Zhiyu
• Jang Yungtaek
• Li sheng-hua
• Wang Ruxi
• Barbosa Peter Mantovanelli

Classifications

• H02M1/4216 Primary

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

• H02M1/12

  Arrangements for reducing harmonics from AC input or output · CPC title

• H02M7/2173

  in a biphase or polyphase circuit arrangement (H02M7/2176 takes precedence; voltage multipliers H02M7/25) · CPC title

• H02M7/219 Primary

  in a bridge configuration · CPC title

• H02M7/2195

  the switches being synchronously commutated at the same frequency of the AC input voltage · CPC title