Current fed high-frequency isolated matrix converter with the corresponding modulation and control schemes

Patent metadata

Field	Value
Publication number	US-11736033-B2
Application number	US-202117622234-A
Country	US
Kind code	B2
Filing date	Feb 4, 2021
Priority date	Dec 21, 2020
Publication date	Aug 22, 2023
Grant date	Aug 22, 2023

Abstract

A current fed high-frequency isolated matrix converter and the corresponding modulation and control schemes are provided. The converter includes a current source full-bridge converter, a high-frequency transformer, a matrix converter, and a three-phase filter. An optimized space vector modulation solution is used for controlling the converter, and by comparing magnitudes of three-phase filter capacitor voltages to determine an action sequence of space vectors, switch tubes are turned on at zero voltage. A current source full-bridge circuit adopts a commutation strategy of a secondary clamping, and by calculating a leakage inductive current commutation time, full-bridge switch tubes are turned off at zero current to achieve safe and reliable commutation, and having advantages of a low system loss, a high efficiency, and a high power density.

First claim

What is claimed is:

1. A current source input high-frequency isolation matrix converter, comprising:
a current source full-bridge converter having an input DC bus connected to a DC side current source,
a high-frequency transformer having a primary coil connected to an output end of the current source full-bridge converter,
a matrix converter having a DC bus connected to a secondary coil of the high-frequency transformer, and
a three-phase filter circuit, wherein a capacitor in each phase filter circuit is connected in parallel between a midpoint of a corresponding phase bridge arm of the matrix converter and a reference potential point, and an output end of the each phase filter circuit is connected to an AC side, wherein
an action sequence of current vectors of the matrix converter is determined according to a line voltage loaded on a filter capacitor, and the current source input high-frequency isolation matrix converter is subjected to a positive half-cycle zero vector action stage, a first active vector action stage, a second active vector action stage, a current source full-bridge converter commutation stage, a current source full-bridge converter freewheeling stage, and a negative half-cycle zero vector action stage in turn under the action sequence of the current vectors.

2. A method for controlling the current source input high-frequency isolation matrix converter according to claim 1 , wherein
the current source full-bridge converter comprises: a first bridge arm formed by a first switch tube and a second switch tube connected in series, and a second bridge arm formed by a third switch tube and a fourth switch tube connected in series, and the matrix converter comprises: an a-phase bridge arm formed by a first bidirectional switch tube and a fourth bidirectional switch tube connected in series, a b-phase bridge arm formed by a third bidirectional switch tube and a sixth bidirectional switch tube connected in series, and a c-phase bridge arm formed by a fifth bidirectional switch tube and a second bidirectional switch tube connected in series; and
three current vectors acting on the matrix converter in a positive half cycle of a switch are a zero vector I 7 , a first active vector I 1+ , and a second active vector I 2+ , corresponding input voltages of the matrix converter are U 0 , U 1 , and U 2 , after line voltages on adjacent two-phase capacitors are compared, and when an action sequence of the three current vectors is determined to be I 7− >I 1+− >I 2+ , U 2 >U 1 >U 0 , and a control process of the current source input high-frequency isolation matrix converter in the positive half cycle of the switch is as follows:
state 1: the positive half-cycle zero vector action stage
at a beginning of a switch cycle, the zero vector I 7 acts on the matrix converter, the first bidirectional switch and the fourth bidirectional switch in the matrix converter are turned on, and the first switch tube and the fourth switch in the current source full-bridge converter are turned on;
state 2: the first active vector action stage
after a zero vector action time has expired, the first active vector I 1+ acts on the matrix converter, the first switch tube and the fourth switch tube in the current source full-bridge converter maintain an ON state, a phase voltage on an ab-phase capacitor is greater than 0, a secondary current of the high-frequency transformer charges an output capacitor of the sixth bidirectional switch tube, the sixth bidirectional switch tube is turned on at zero voltage, the fourth bidirectional switch tube is turned off, a secondary voltage of the high-frequency transformer is equal to a line voltage on the ab-phase capacitor, and an energy is fed from a DC side to the AC side;
state 3: the second active vector action stage
after an action time of the first active vector I 1+ has expired, the second active vector I 2+ acts on the matrix converter, the first switch tube and the fourth switch tube in the current source full-bridge converter maintain the ON state, a line voltage on an ac-phase capacitor is greater than the line voltage on the ab-phase capacitor, the secondary current of the high-frequency transformer charges an output capacitor of the second bidirectional switch, the second bidirectional switch is turned on at zero voltage, the sixth bidirectional switch is turned off, the secondary voltage of the high-frequency transformer is equal to the line voltage on the ac-phase capacitor, and the energy is fed from the DC side to the AC side;
state 4: the current source full-bridge converter commutation stage
in the matrix converter, the first bidirectional switch tube and the second bidirectional switch tube maintain the ON state, the first, second, third, and fourth switches of the current source full-bridge converter are overlapped and turned on, and the second switch tube and the third switch tube are turned on at zero current;
state 5: the current source full-bridge converter freewheeling stage
after an overlapped ON time of the first, second, third, and fourth switches of the current source full-bridge converter has expired, the second bidirectional switch tube in the matrix converter is turned off, the fourth bidirectional switch tube is turned on at zero voltage, a secondary voltage of the current source full-bridge converter is zero, anti-parallel diodes of the first switch tube and the fourth switch tube are freewheeling, and the first switch tube and the fourth switch tube are turned off at zero current; and
state 6: the negative half-cycle zero vector action stage
after the first switch tube and the fourth switch tube are turned off at zero current, the zero vector I 7 acts on the matrix converter, the first bidirectional switch and the fourth bidirectional switch tube in the matrix converter maintain the ON state, and the second switch tube and the third switch tube in the current source full-bridge converter maintain the ON state.

3. The method according to claim 2 , wherein action times of the three current vectors of the matrix converter are corrected according to the overlapped ON time of the first, second, third, and fourth switches of the current source full-bridge converter to obtain corrected action times.

4. The method according to claim 3 , wherein the corrected action times of the three current vectors of the matrix converter are:

{

T
1

=

T
s

⁢

m
a

⁢

sin
(

π
6

-

θ
i

)

T
2

=

T

Assignees

• Univ Southeast

Inventors

• Wang Zheng
• Xu Yang
• Liu Pengcheng
• Zou Zhixiang
• Cheng Ming

Classifications

• H02M7/4807 Primary

  having a high frequency intermediate AC stage · CPC title

• H02M1/0058

  by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero (using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826) · CPC title

• H02M7/53876

  based on synthesising a desired voltage vector via the selection of appropriate fundamental voltage vectors, and corresponding dwelling times · CPC title

• H02M7/537 Primary

  using semiconductor devices only, e.g. single switched pulse inverters · CPC title

• H02M7/5387

  in a bridge configuration · CPC title