Wide-range output three-phase isolation type bidirectional single-stage converter

Abstract

The invention provides a wide-range output three-phase isolation type bidirectional single-stage converter which comprises a three-phase alternating current side voltage port, a direct current voltage port, a first alternating current side circuit unit, a second alternating current side circuit unit, a third alternating current side circuit unit, a first transformer, a second transformer, a third transformer and a wide voltage output unit. Two ends of the second winding are respectively connected with the midpoint of the first bridge arm and the midpoint of the second bridge arm of the wide voltage output unit; the second transformer comprises a third winding and a fourth winding. The two ends of the fourth winding are connected with the midpoint of the third bridge arm and the midpoint of the second bridge arm of the wide voltage output unit respectively. The third transformer comprises a fifth winding and a sixth winding. The two ends of the fifth winding are connected with the midpoint of the fourth bridge arm and the midpoint of the second bridge arm of the wide voltage output unit respectively. And two ends of the wide voltage output unit are respectively connected with the seventh port and the eighth port. The working efficiency and the accuracy of the converter can be greatly improved, and wide-range output is realized by adopting fewer switching tubes.

Description

Technical Field

[0001] The invention relates to the technical field of power electronics, and in particular to a wide-range output three-phase isolated bidirectional single-stage converter. Background Art

[0002] In the related art, most isolated AC / DC bidirectional converters adopt a two-stage structure, which consists of a first-stage bidirectional non-isolated AC / DC converter and a first-stage bidirectional isolated DC / DC converter, and the two stages are connected by an electrolytic capacitor. However, the two-stage isolated AC / DC bidirectional converter has the following disadvantages: (1) The two-stage structure requires a large number of switches and larger magnetic components, resulting in higher losses, which leads to lower working efficiency and accuracy of the converter; (2) The full-bridge architecture is used, and the output voltage is limited. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a wide-range output three-phase isolated bidirectional single-stage converter, which only includes one stage of power conversion, can greatly improve the working efficiency and accuracy of the converter, and adopts a T-type three-level structure on the DC side, which can achieve a wide range of output with fewer switching tubes.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A wide-range output three-phase isolated bidirectional single-stage converter, comprising: a three-phase AC side voltage port, a DC voltage port, first to third AC side circuit units, first to third transformers and a wide voltage output unit, wherein the three-phase AC port comprises first to sixth ports; the DC voltage port comprises a seventh port and an eighth port; the first transformer comprises a first winding and a second winding, the first winding is provided with a first center tap, the first center tap is connected to the first end of the first AC side circuit unit, the two ends of the first winding are respectively connected to the second end and the third end of the first AC side circuit unit, and the two ends of the second winding are respectively connected to the first bridge arm midpoint and the second bridge arm midpoint of the wide voltage output unit; the second transformer comprises a third winding and a fourth winding, the third winding is provided with a second center tap, the second center tap is connected to the first end of the second AC side circuit unit, the two ends of the third winding are respectively connected to the second AC side circuit unit, and the two ends of the third winding are respectively connected to the second AC side circuit unit. The second end and the third end of the current side circuit unit are connected, and the two ends of the fourth winding are respectively connected to the third bridge arm midpoint and the second bridge arm midpoint of the wide voltage output unit; the third transformer includes a fifth winding and a sixth winding, and the fifth winding is provided with a third center tap, and the third center tap is connected to the first end of the third AC side circuit unit, and the two ends of the fifth winding are respectively connected to the second end and the third end of the third AC side circuit unit, and the two ends of the fifth winding are respectively connected to the fourth bridge arm midpoint and the second bridge arm midpoint of the wide voltage output unit; the fourth end and the fifth end of the first AC side circuit unit are respectively connected to the first port and the second port; the fourth end and the fifth end of the second AC side circuit unit are respectively connected to the third port and the fourth port; the fourth end and the fifth end of the third AC side circuit unit are respectively connected to the fifth end and the sixth port; the two ends of the wide voltage output unit are respectively connected to the seventh port and the eighth port.

[0006] In one embodiment of the present invention, the first AC side circuit unit includes: a first filter circuit subunit, a first full-bridge circuit subunit, a first half-bridge circuit subunit, a first coupling circuit subunit and a first bus capacitor, wherein one end of the first filter circuit subunit is connected to the first port, the other end of the first filter circuit subunit is connected to the first center tap, the midpoints of the two bridge arms of the first full-bridge circuit subunit are respectively connected to the two ends of the first winding through the first coupling circuit subunit, the two ends of the first full-bridge circuit subunit are respectively connected to the two ends of the first half-bridge circuit subunit, the midpoint of the bridge arm of the first half-bridge circuit subunit is connected to the second port, and the two ends of the first half-bridge circuit subunit are also connected to the first bus capacitor; the second AC side circuit unit includes: a second filter circuit subunit, a second full-bridge circuit subunit, a second half-bridge circuit subunit, a second coupling circuit subunit and a second bus capacitor, wherein one end of the second filter circuit subunit is connected to the third port, the other end of the second filter circuit subunit is connected to the second center tap, and the second The midpoints of the two bridge arms of the full-bridge circuit subunit are respectively connected to the two ends of the third winding through the second coupling circuit subunit, the two ends of the second full-bridge circuit subunit are respectively connected to the two ends of the second half-bridge circuit subunit, the midpoint of the bridge arm of the second half-bridge circuit subunit is connected to the fourth port, and the two ends of the second half-bridge circuit subunit are also connected to the second bus capacitor; the third AC side circuit unit includes: a third filter circuit subunit, a third full-bridge circuit subunit, a third half-bridge circuit subunit, a third coupling circuit subunit and a third bus capacitor, wherein one end of the third filtering circuit subunit is connected to the fifth port, the other end of the third filtering circuit subunit is connected to the third center tap, the two bridge arm midpoints of the third full-bridge circuit subunit are respectively connected to the two ends of the fifth winding through the third coupling circuit subunit, the two ends of the third full-bridge circuit subunit are respectively connected to the two ends of the third half-bridge circuit subunit, the bridge arm midpoint of the third half-bridge circuit subunit is connected to the sixth port, and the two ends of the third half-bridge circuit subunit are also connected to the third bus capacitor.

[0007] In one embodiment of the present invention, the first full-bridge circuit subunit includes: a first switch tube and a second switch tube connected in series and a third switch tube and a fourth switch tube connected in series, wherein the second end of the first switch tube is connected to the first end of the second switch tube, and the connection point between the first switch tube and the second switch tube is a midpoint of a bridge arm of the first full-bridge circuit subunit; the second end of the third switch tube is connected to the first end of the fourth switch tube, and the connection point between the third switch tube and the fourth switch tube is another midpoint of a bridge arm of the first full-bridge circuit subunit, the first end of the third switch tube is connected to the first end of the first switch tube, and the second end of the fourth switch tube is connected to the second end of the second switch tube; the second full-bridge circuit subunit includes: a fifth switch tube and a sixth switch tube connected in series and a seventh switch tube and an eighth switch tube connected in series, wherein the second end of the fifth switch tube is connected to the first end of the sixth switch tube, and the connection point between the fifth switch tube and the sixth switch tube is a midpoint of a bridge arm of the second full-bridge circuit subunit; The second end of the seventh switch tube is connected to the first end of the eighth switch tube, and the connection point between the seventh switch tube and the eighth switch tube is another bridge arm midpoint of the second full-bridge circuit subunit, the first end of the seventh switch tube is connected to the first end of the fifth switch tube, and the second end of the eighth switch tube is connected to the second end of the sixth switch tube; the third full-bridge circuit subunit includes: a ninth switch tube and a tenth switch tube connected in series, and an eleventh switch tube and a twelfth switch tube connected in series, wherein the second end of the ninth switch tube is connected to the first end of the tenth switch tube, and the connection point between the ninth switch tube and the tenth switch tube is a bridge arm midpoint of the third full-bridge circuit subunit; the second end of the eleventh switch tube is connected to the first end of the twelfth switch tube, and the connection point between the eleventh switch tube and the twelfth switch tube is another bridge arm midpoint of the third full-bridge circuit subunit, the first end of the eleventh switch tube is connected to the first end of the ninth switch tube, and the second end of the twelfth switch tube is connected to the second end of the tenth switch tube.

[0008] In one embodiment of the present invention, the first half-bridge circuit subunit includes: a thirteenth switch tube and a fourteenth switch tube connected in series, wherein the second end of the thirteenth switch tube is connected to the first end of the fourteenth switch tube, the connection point between the thirteenth switch tube and the fourteenth switch tube is the midpoint of the bridge arm of the first half-bridge circuit subunit, the first end of the thirteenth switch tube is connected to the first end of the third switch tube, and the second end of the fourteenth switch tube is connected to the second end of the fourth switch tube; the second half-bridge circuit subunit includes: a fifteenth switch tube and a sixteenth switch tube connected in series, wherein the second end of the fifteenth switch tube is connected to the first end of the sixteenth switch tube, the fifteenth switch tube is connected to the The connection point of the sixteenth switch tube is the midpoint of the bridge arm of the second half-bridge circuit sub-unit, the first end of the fifteenth switch tube is connected to the first end of the seventh switch tube, and the second end of the sixteenth switch tube is connected to the second end of the eighth switch tube; the third half-bridge circuit sub-unit includes: a seventeenth switch tube and an eighteenth switch tube connected in series, wherein the second end of the seventeenth switch tube is connected to the first end of the eighteenth switch tube, the connection point between the seventeenth switch tube and the eighteenth switch tube is the midpoint of the bridge arm of the third half-bridge circuit sub-unit, the first end of the seventeenth switch tube is connected to the first end of the eleventh switch tube, and the second end of the eighteenth switch tube is connected to the second end of the twelfth switch tube.

[0009] In one embodiment of the present invention, the first coupling circuit subunit includes: a first coupling inductor and a second coupling inductor, wherein one end of the first coupling inductor is connected to a midpoint of a bridge arm of the first full-bridge circuit subunit, and the other end of the first coupling inductor is connected to one end of the first winding; one end of the second coupling inductor is connected to the midpoint of another bridge arm of the first full-bridge circuit subunit, and the other end of the second coupling inductor is connected to the other end of the first winding; the second coupling circuit subunit includes: a third coupling inductor and a fourth coupling inductor, wherein one end of the third coupling inductor is connected to a midpoint of a bridge arm of the second full-bridge circuit subunit, and the third coupling inductor is connected to the midpoint of another bridge arm of the second full-bridge circuit subunit. The other end of the coupled inductor is connected to one end of the third winding; one end of the fourth coupled inductor is connected to the midpoint of another bridge arm of the second full-bridge circuit subunit, and the other end of the fourth coupled inductor is connected to the other end of the third winding; the third coupled circuit subunit includes: a fifth coupled inductor and a sixth coupled inductor, wherein one end of the fifth coupled inductor is connected to the midpoint of one bridge arm of the third full-bridge circuit subunit, and the other end of the fifth coupled inductor is connected to one end of the fifth winding; one end of the sixth coupled inductor is connected to the midpoint of another bridge arm of the third full-bridge circuit subunit, and the other end of the sixth coupled inductor is connected to the other end of the fifth winding.

[0010] In one embodiment of the present invention, the first filter circuit subunit includes: a first filter inductor and a first resistor, wherein one end of the first filter inductor is connected to the first port, one end of the first resistor is connected to the other end of the first filter inductor, and the other end of the first resistor is connected to the first center tap; the second filter circuit subunit includes: a second filter inductor and a second resistor, wherein one end of the second filter inductor is connected to the third port, one end of the second resistor is connected to the other end of the second filter inductor, and the other end of the second resistor is connected to the second center tap; the third filter circuit subunit includes: a third filter inductor and a third resistor, wherein one end of the third filter inductor is connected to the fifth port, one end of the third resistor is connected to the other end of the third filter inductor, and the other end of the third resistor is connected to the third center tap.

[0011] In one embodiment of the present invention, the wide voltage output unit includes: a nineteenth switch tube and a twenty-th switch tube connected in series, wherein the second end of the nineteenth switch tube is connected to the first end of the twenty-th switch tube, and the connection point between the nineteenth switch tube and the twenty-th switch tube is the first bridge arm midpoint of the wide voltage output unit; a twenty-first switch tube and a twenty-second switch tube connected in series, wherein the second end of the twenty-first switch tube is connected to the first end of the twenty-second switch tube, the first end of the twenty-first switch tube is connected to the first end of the nineteenth switch tube, the second end of the twenty-second switch tube is connected to the second end of the twenty-th switch tube, and the connection point between the twenty-first switch tube and the twenty-second switch tube is the third bridge arm midpoint of the wide voltage output unit; a twenty-third switch tube and a twenty-fourth switch tube connected in series, wherein the second end of the twenty-third switch tube is connected to the first end of the twenty-fourth switch tube, the first end of the twenty-third switch tube is connected to the first end of the twenty-first switch tube, the second end of the twenty-fourth switch tube is connected to the second end of the twenty-second switch tube, and the connection point between the twenty-third switch tube and the twenty-fourth switch tube is the fourth bridge arm midpoint of the wide voltage output unit; a first capacitor and a second capacitor connected in series, wherein one end of the first capacitor is connected to one end of the second capacitor , the other end of the first capacitor is respectively connected to the first end of the twenty-third switch tube and the seventh port, the other end of the second capacitor is respectively connected to the second end of the twenty-fourth switch tube and the eighth port, and the connection point of the first capacitor and the second capacitor is the second bridge arm midpoint of the wide voltage output unit; the twenty-fifth switch tube and the twenty-sixth switch tube are connected in series, the first end of the twenty-fifth switch tube is connected to the first bridge arm midpoint of the wide voltage output unit, the second end of the twenty-fifth switch tube is connected to the second end of the twenty-sixth switch tube, and the first end of the twenty-sixth switch tube is connected to the second bridge arm midpoint of the wide voltage output unit; The twenty-seventh switch tube and the twenty-eighth switch tube, the first end of the twenty-seventh switch tube is connected to the midpoint of the third bridge arm of the wide voltage output unit, the second end of the twenty-seventh switch tube is connected to the second end of the twenty-eighth switch tube, and the first end of the twenty-eighth switch tube is connected to the midpoint of the second bridge arm of the wide voltage output unit; the twenty-ninth switch tube and the thirtieth switch tube are connected in series, the first end of the twenty-ninth switch tube is connected to the midpoint of the fourth bridge arm of the wide voltage output unit, the second end of the twenty-ninth switch tube is connected to the second end of the thirtieth switch tube, and the first end of the thirtieth switch tube is connected to the midpoint of the second bridge arm of the wide voltage output unit.

[0012] Beneficial effects of the present invention:

[0013] The wide-range output three-phase isolated bidirectional single-stage converter of the present invention includes only one-stage power conversion, which can greatly improve the working efficiency and accuracy of the converter, and adopts a T-type three-level structure on the DC side, which can achieve wide-range output with fewer switching tubes. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic structural diagram of a wide-range output three-phase isolated bidirectional single-stage converter according to an embodiment of the present invention;

[0015] Figure 2 It is a structural schematic diagram of a control system of a wide-range output three-phase isolated bidirectional single-stage converter according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] Figure 1 1 is a schematic structural diagram of a wide-range output three-phase isolated bidirectional single-stage converter according to an embodiment of the present invention.

[0018] Specifically, Figure 1 As shown, the wide-range output three-phase isolated bidirectional single-stage converter of an embodiment of the present invention may include: a three-phase AC side voltage port 100, a DC voltage port 200, first to third AC side circuit units 300~500, first to third transformers 600~800 and a wide voltage output unit 900.

[0019] Among them, the three-phase AC port 100 includes the first to sixth ports (i.e., the first port A, the second port B, the third port C, the fourth port D, the fifth port E and the sixth port F); the DC voltage port 200 includes the seventh port G and the eighth port H; the first transformer 600 includes a first winding 610 and a second winding 620, the first winding 610 is provided with a first center tap, the first center tap is connected to the first end of the first AC side circuit unit 300, the two ends of the first winding 610 are respectively connected to the second end and the third end of the first AC side circuit unit 300, and the two ends of the second winding 620 are respectively connected to the first bridge arm midpoint and the second bridge arm midpoint of the wide voltage output unit 900; the second transformer 700 includes a third winding 710 and a fourth winding 720, the third winding 710 is provided with a second center tap, the second center tap is connected to the first end of the second AC side circuit unit 400, and the two ends of the third winding 710 are respectively connected to the second end and the third end of the second AC side circuit unit 400. The third transformer 800 includes a fifth winding 810 and a sixth winding 820, the fifth winding 810 is provided with a third center tap, the third center tap is connected to the first end of the third AC side circuit unit 500, the two ends of the fifth winding 810 are respectively connected to the second end and the third end of the third AC side circuit unit 500, and the two ends of the fifth winding 810 are respectively connected to the fourth bridge arm midpoint and the second bridge arm midpoint of the wide voltage output unit 900; the fourth end and the fifth end of the first AC side circuit unit 300 are respectively connected to the first port A and the second port B; the fourth end and the fifth end of the second AC side circuit unit 400 are respectively connected to the third port C and the fourth port D; the fourth end and the fifth end of the third AC side circuit unit 500 are respectively connected to the fifth end E and the sixth port F; the two ends of the wide voltage output unit 900 are respectively connected to the seventh port G and the eighth port H.

[0020] In one embodiment of the present invention, Figure 1As shown, the first AC side circuit unit 300 may include: a first filter circuit subunit 310, a first full-bridge circuit subunit 320, a first half-bridge circuit subunit 330, a first coupling circuit subunit 340 and a first bus capacitor 350, wherein one end of the first filter circuit subunit 310 is connected to the first port A, the other end of the first filter circuit subunit 310 is connected to the first center tap, the midpoints of the two bridge arms of the first full-bridge circuit subunit 320 are respectively connected to the two ends of the first winding 610 through the first coupling circuit subunit 340, and the two ends of the first full-bridge circuit subunit 320 are respectively connected to the first half-bridge circuit subunit 330. The two ends of the bridge circuit subunit 330 are connected, the midpoint of the bridge arm of the first half-bridge circuit subunit 330 is connected to the second port B, and the two ends of the first half-bridge circuit subunit 330 are also connected to the first bus capacitor 350; the second AC side circuit unit 400 includes: a second filter circuit subunit 410, a second full-bridge circuit subunit 420, a second half-bridge circuit subunit 430, a second coupling circuit subunit 440 and a second bus capacitor 450, wherein one end of the second filter circuit subunit 410 is connected to the third port C, the other end of the second filter circuit subunit 410 is connected to the second center tap, and the second full-bridge circuit subunit 420 is connected to the second center tap. The midpoints of the two bridge arms of the full-bridge circuit subunit 420 are respectively connected to the two ends of the third winding 710 through the second coupling circuit subunit 440, the two ends of the second full-bridge circuit subunit 420 are respectively connected to the two ends of the second half-bridge circuit subunit 430, the midpoint of the bridge arm of the second half-bridge circuit subunit 430 is connected to the fourth port D, and the two ends of the second half-bridge circuit subunit 430 are also connected to the second bus capacitor 450; the third AC side circuit unit 500 includes: a third filtering circuit subunit 510, a third full-bridge circuit subunit 520, a third half-bridge circuit subunit 530, and a third coupling circuit subunit 540. and a third bus capacitor 550, wherein one end of the third filter circuit subunit 510 is connected to the fifth port E, the other end of the third filter circuit subunit 510 is connected to the third center tap, the two bridge arm midpoints of the third full-bridge circuit subunit 520 are respectively connected to the two ends of the fifth winding 810 through the third coupling circuit subunit 540, the two ends of the third full-bridge circuit subunit 520 are respectively connected to the two ends of the third half-bridge circuit subunit 530, the bridge arm midpoint of the third half-bridge circuit subunit 530 is connected to the sixth port F, and the two ends of the third half-bridge circuit subunit 530 are also connected to the third bus capacitor 550.

[0021] In one embodiment of the present invention, Figure 1As shown, the first full-bridge circuit subunit 320 includes: a first switch tube S1 and a second switch tube S2 connected in series, and a third switch tube S3 and a fourth switch tube S4 connected in series, wherein the second end of the first switch tube S1 is connected to the first end of the second switch tube S2, and the connection point a between the first switch tube S1 and the second switch tube S2 is a midpoint of a bridge arm of the first full-bridge circuit subunit 320; the second end of the third switch tube S3 is connected to the first end of the fourth switch tube S4, and the connection point b between the third switch tube S3 and the fourth switch tube S4 is another midpoint of the first full-bridge circuit subunit 320. A bridge arm midpoint, a first end of the third switch tube S3 is connected to a first end of the first switch tube S1, and a second end of the fourth switch tube S4 is connected to a second end of the second switch tube S2; the second full-bridge circuit subunit 420 includes: a fifth switch tube S5 and a sixth switch tube S6 connected in series, and a seventh switch tube S7 and an eighth switch tube S8 connected in series, wherein the second end of the fifth switch tube S5 is connected to the first end of the sixth switch tube S6, and the connection point c of the fifth switch tube S5 and the sixth switch tube S6 is a bridge arm midpoint of the second full-bridge circuit subunit 420; the seventh switch tube S The second end of the seventh switch tube S7 is connected to the first end of the eighth switch tube S8, the connection point d between the seventh switch tube S7 and the eighth switch tube S8 is the other bridge arm midpoint of the second full-bridge circuit sub-unit 420, the first end of the seventh switch tube S7 is connected to the first end of the fifth switch tube S5, and the second end of the eighth switch tube S8 is connected to the second end of the sixth switch tube S6; the third full-bridge circuit sub-unit 520 includes: a ninth switch tube S9 and a tenth switch tube S10 connected in series, and an eleventh switch tube S11 and a twelfth switch tube S12 connected in series, wherein the second end of the ninth switch tube S9 is connected to the first end of the fifth switch tube S5, and the second end of the eighth switch tube S8 is connected to the second end of the sixth switch tube S6; The first end of the tenth switch tube S10 is connected, and the connection point e of the ninth switch tube S9 and the tenth switch tube S10 is a midpoint of a bridge arm of the third full-bridge circuit sub-unit 520; the second end of the eleventh switch tube S11 is connected to the first end of the twelfth switch tube S12, and the connection point f of the eleventh switch tube S11 and the twelfth switch tube S12 is another midpoint of the bridge arm of the third full-bridge circuit sub-unit 520, the first end of the eleventh switch tube S11 is connected to the first end of the ninth switch tube S9, and the second end of the twelfth switch tube S12 is connected to the second end of the tenth switch tube S10.

[0022] In one embodiment of the present invention, Figure 1As shown, the first half-bridge circuit subunit 330 includes: a thirteenth switch tube S13 and a fourteenth switch tube S14 connected in series, wherein the second end of the thirteenth switch tube S13 is connected to the first end of the fourteenth switch tube S14, and the connection point g between the thirteenth switch tube S13 and the fourteenth switch tube S14 is the midpoint of the bridge arm of the first half-bridge circuit subunit 330, the first end of the thirteenth switch tube S13 is connected to the first end of the third switch tube S3, and the second end of the fourteenth switch tube S14 is connected to the second end of the fourth switch tube S4; the second half-bridge circuit subunit 430 includes: a fifteenth switch tube S15 and a sixteenth switch tube S16 connected in series, wherein the second end of the fifteenth switch tube S15 is connected to the first end of the sixteenth switch tube S16, and the fifteenth switch tube S15 is connected to the sixteenth switch tube S4. The connection point h of the switch tube S16 is the midpoint of the bridge arm of the second half-bridge circuit sub-unit, the first end of the fifteenth switch tube S15 is connected to the first end of the seventh switch tube S7, and the second end of the sixteenth switch tube S16 is connected to the second end of the eighth switch tube S8; the third half-bridge circuit sub-unit 530 includes: a seventeenth switch tube S17 and an eighteenth switch tube S18 connected in series, wherein the second end of the seventeenth switch tube S17 is connected to the first end of the eighteenth switch tube S18, and the connection point i of the seventeenth switch tube S17 and the eighteenth switch tube S18 is the midpoint of the bridge arm of the third half-bridge circuit sub-unit 530, the first end of the seventeenth switch tube S17 is connected to the first end of the eleventh switch tube S11, and the second end of the eighteenth switch tube S18 is connected to the second end of the twelfth switch tube S12.

[0023] In one embodiment of the present invention, Figure 1As shown, the first coupling circuit subunit 340 includes: a first coupling inductor L1 and a second coupling inductor L2, wherein one end of the first coupling inductor L1 is connected to a midpoint of a bridge arm of the first full-bridge circuit subunit 320, and the other end of the first coupling inductor L1 is connected to one end of the first winding 610; one end of the second coupling inductor L2 is connected to the midpoint of another bridge arm of the first full-bridge circuit subunit 320, and the other end of the second coupling inductor L2 is connected to the other end of the first winding 610; the second coupling circuit subunit 440 includes: a third coupling inductor L3 and a fourth coupling inductor L4, wherein one end of the third coupling inductor L3 is connected to a midpoint of a bridge arm of the second full-bridge circuit subunit 420, and the third coupling inductor L The other end of the fourth coupling inductor L4 is connected to one end of the third winding 710; one end of the fourth coupling inductor L4 is connected to the other bridge arm midpoint of the second full-bridge circuit sub-unit 420, and the other end of the fourth coupling inductor L4 is connected to the other end of the third winding 710; the third coupling circuit sub-unit 540 includes: a fifth coupling inductor L5 and a sixth coupling inductor L6, wherein one end of the fifth coupling inductor L5 is connected to the middle point of one bridge arm of the third full-bridge circuit sub-unit 520, and the other end of the fifth coupling inductor L5 is connected to one end of the fifth winding 810; one end of the sixth coupling inductor L6 is connected to the other bridge arm midpoint of the third full-bridge circuit sub-unit 520, and the other end of the sixth coupling inductor L6 is connected to the other end of the fifth winding 810.

[0024] In one embodiment of the present invention, Figure 1 As shown, the first filter circuit subunit 310 includes: a first filter inductor L7 and a first resistor R1, wherein one end of the first filter inductor L7 is connected to the first port A, one end of the first resistor R1 is connected to the other end of the first filter inductor L7, and the other end of the first resistor R1 is connected to the first center tap; the second filter circuit subunit 410 includes: a second filter inductor L8 and a second resistor R2, wherein one end of the second filter inductor L8 is connected to the third port C, one end of the second resistor R2 is connected to the other end of the second filter inductor L8, and the other end of the second resistor R2 is connected to the second center tap; the third filter circuit subunit 510 includes: a third filter inductor L9 and a third resistor R3, wherein one end of the third filter inductor L9 is connected to the fifth port E, one end of the third resistor R3 is connected to the other end of the third filter inductor L9, and the other end of the third resistor R3 is connected to the third center tap.

[0025] In one embodiment of the present invention, Figure 1As shown, the wide voltage output unit 900 includes: a nineteenth switch tube S19 and a twentieth switch tube S20 connected in series, a twenty-first switch tube S21 and a twenty-second switch tube S22 connected in series, a twenty-third switch tube S23 and a twenty-fourth switch tube S24 connected in series, a first capacitor and a second capacitor connected in series, a twenty-fifth switch tube S25 and a twenty-sixth switch tube S26 connected in series, a twenty-seventh switch tube S27 and a twenty-eighth switch tube S28 connected in series, and a twenty-ninth switch tube S29 and a thirtieth switch tube S30 connected in series.

[0026] Among them, the second end of the nineteenth switch tube S19 is connected to the first end of the twentieth switch tube S20, and the connection point j between the nineteenth switch tube S19 and the twentieth switch tube S20 is the midpoint of the first bridge arm of the wide voltage output unit 900; the second end of the twenty-first switch tube S21 is connected to the first end of the twenty-second switch tube S22, the first end of the twenty-first switch tube S21 is connected to the first end of the nineteenth switch tube S19, the second end of the twenty-second switch tube S22 is connected to the second end of the twentieth switch tube S20, and the connection point k between the twenty-first switch tube S21 and the twenty-second switch tube S22 is the wide voltage output unit 900. The third bridge arm midpoint of the wide voltage output unit 900; the second end of the twenty-third switch tube S23 is connected to the first end of the twenty-fourth switch tube S24, the first end of the twenty-third switch tube S23 is connected to the first end of the twenty-first switch tube S21, the second end of the twenty-fourth switch tube S24 is connected to the second end of the twenty-second switch tube S22, and the connection point m between the twenty-third switch tube S23 and the twenty-fourth switch tube S24 is the fourth bridge arm midpoint of the wide voltage output unit 900; one end of the first capacitor C1 is connected to one end of the second capacitor C2, and the other end of the first capacitor C1 is connected to the twenty-third switch tube S23 and the twenty-fourth switch tube S24 respectively. The first end of the twenty-fifth switch tube S25 is connected to the midpoint of the first bridge arm of the wide voltage output unit 900, the second end of the twenty-fifth switch tube S25 is connected to the second end of the twenty-sixth switch tube S26, and the first end of the twenty-sixth switch tube S26 is connected to the midpoint of the second bridge arm of the wide voltage output unit 900; the first end of the twenty-seventh switch tube S25 is connected to the midpoint of the first bridge arm of the wide voltage output unit 900, the second end of the twenty-fifth switch tube S25 is connected to the second end of the twenty-sixth switch tube S26, and the first end of the twenty-sixth switch tube S26 is connected to the midpoint of the second bridge arm of the wide voltage output unit 900; the The first end of the switch S27 is connected to the midpoint of the third bridge arm of the wide voltage output unit 900, the second end of the twenty-seventh switch S27 is connected to the second end of the twenty-eighth switch S28, and the first end of the twenty-eighth switch S28 is connected to the midpoint of the second bridge arm of the wide voltage output unit 900; the first end of the twenty-ninth switch S29 is connected to the midpoint of the fourth bridge arm of the wide voltage output unit 900, the second end of the twenty-ninth switch S29 is connected to the second end of the thirtieth switch S30, and the first end of the thirtieth switch S30 is connected to the midpoint of the second bridge arm of the wide voltage output unit 900.

[0027] In order to enable those skilled in the art to more clearly understand the wide-range output three-phase isolated bidirectional single-stage converter according to the embodiment of the present invention, the working mode of the wide-range output three-phase isolated bidirectional single-stage converter is described in detail below in combination with specific embodiments.

[0028] Taking a certain phase power supply corresponding to the first port A and the second port B as an example, the rectification or inversion of a certain phase power supply corresponding to the third port C and the fourth port D and a certain phase power supply corresponding to the fifth port E and the sixth port F is similar to that of a certain phase power supply corresponding to the first port A and the second port B.

[0029] Specifically, by inputting a driving signal to the driving terminals of the first to fourth switch tubes S1 to S4 to control the first to fourth switch tubes S1 to S4 to be turned on or off, the first full-bridge circuit subunit 320 is controlled to operate in the following two modes:

[0030] Mode 1: when the first switch tube S1 and the fourth switch tube S4 are in the on state, the second switch tube S2 and the third switch tube S3 are in the off state; Mode 2: when the second switch tube S2 and the third switch tube S3 are in the on state, the first switch tube S1 and the fourth switch tube S4 are in the off state.

[0031] The duty cycle of the driving signal of the first to fourth switch tubes S1 to S4 is 50%, and only one of the two switch tubes in the same bridge arm is in the on state. s Within the time frame, Mode 1 and Mode 2 are executed once each, and the duration is 50% each.

[0032] By inputting a driving signal to the driving ends of the thirteenth switch tube S13 and the fourteenth switch tube S14 to control the thirteenth switch tube S13 and the fourteenth switch tube S14 to be turned on or off, the first half-bridge circuit sub-unit 330 is controlled to work in the following manner:

[0033] If the three-phase single-stage isolated bidirectional converter works in the rectification mode, when the AC terminal voltage V g1 When the AC terminal voltage V g1 When the AC terminal voltage V g1 When the AC terminal voltage V g1 When is negative, the fourteenth switch tube S14 is in the on state, and the thirteenth switch tube S13 is in the off state.

[0034] According to a specific embodiment of the present invention, taking the positive half-cycle of the rectification mode as an example, wherein the current at the AC end is greater than 0, it is a positive half-cycle; the current at the AC end is less than 0, it is a negative half-cycle, and the positive half-cycle and the negative half-cycle are symmetrical to each other. The positive half-cycle is used as an example for explanation below. The operation mode of the negative half-cycle is the same, and the inversion mode can also refer to the rectification mode.

[0035] Specifically, in the first stage of the positive half-cycle working stage of the rectification mode, the first switch tube S1, the fourth switch tube S4, the fourteenth switch tube S14, the twentieth switch tube S20 and the twenty-fifth switch tube S25 are in the on state, and the second switch tube S2, the third switch tube S3, the thirteenth switch tube S13, the nineteenth switch tube S19 and the twenty-sixth switch tube S26 are in the off state. At this time, the output current ik1 rises linearly, charging the second capacitor C2, and the voltage U across the second capacitor C2 C2 Equal to the voltage U between connection point j and connection point n jn .

[0036] In the second stage of the positive half cycle of the rectification mode, the first switch tube S1, the fourth switch tube S4, the fourteenth switch tube S14, the twenty-fifth switch tube S25 and the twenty-sixth switch tube S26 are in the on state, and the second switch tube S2, the third switch tube S3, the thirteenth switch tube S13, the nineteenth switch tube S19 and the twentieth switch tube S20 are in the off state. At this time, the first transformer 600 is in a short-circuit state, the first coupling circuit subunit 340 enters the energy storage state, and the output current ik1 rises linearly.

[0037] In the third stage of the positive half cycle of the rectification mode, the first switch tube S1, the fourth switch tube S4, the fourteenth switch tube S14, the nineteenth switch tube S19 and the twenty-sixth switch tube S26 are in the on state, and the second switch tube S2, the third switch tube S3, the thirteenth switch tube S13, the twentieth switch tube S20 and the twenty-first switch tube S21 are in the off state. At this time, the output current ik1 decreases linearly and is charged into the first capacitor C1. The voltage U across the first capacitor C1 C1 Equal to the voltage U between connection point j and connection point n jn .

[0038] In the fourth stage of the positive half cycle of the rectification mode, the second switch tube S2, the third switch tube S3, the fourteenth switch tube S14, the nineteenth switch tube S19 and the twenty-sixth switch tube S26 are in the on state, and the first switch tube S1, the fourth switch tube S4, the thirteenth switch tube S13, the twentieth switch tube S20 and the twenty-fifth switch tube 25 are in the off state. At this time, the output current ik1 decreases linearly and is charged into the first capacitor C1. The voltage U across the first capacitor C1 C1 Equal to the voltage U between connection point j and connection point njn .

[0039] In the fifth stage of the positive half cycle of the rectification mode, the second switch tube S2, the third switch tube S3, the fourteenth switch tube S14, the twenty-fifth switch tube S25 and the twenty-sixth switch tube S26 are in the on state, and the first switch tube S1, the fourth switch tube S4, the thirteenth switch tube S13, the nineteenth switch tube S19 and the twentieth switch tube S20 are in the off state. At this time, the first transformer 600 is in a short-circuit state, the first coupling circuit subunit 340 enters the energy storage state, and the output current ik1 rises linearly.

[0040] In the sixth stage of the positive half cycle of the rectification mode, the second switch tube S2, the third switch tube S3, the fourteenth switch tube S14, the twentieth switch tube S20 and the twenty-fifth switch tube S25 are in the on state, and the first switch tube S1, the fourth switch tube S4, the thirteenth switch tube S13, the nineteenth switch tube S19 and the twenty-sixth switch tube S26 are in the off state. At this time, the output current ik1 rises linearly, charging the second capacitor C2, and the voltage U across the second capacitor C2 C2 Equal to the voltage U between connection point j and connection point n jn .

[0041] Therefore, the AC output voltage V0 = U C1 +U C2 =2U de , that is, the present invention can improve the output voltage range, and the output voltage can be increased by two times compared with the traditional structure. In addition, the bridge arms of the primary side of the transformer are staggered 180 degrees, and the duty cycle is fixed at 50%, which can achieve complete cancellation of high-frequency current components and obtain a relatively pure sine wave. The first filter inductor L7 is used to filter out high-frequency ripples, and the inductance is small. The first bus capacitor 350 does not need to maintain a constant DC voltage, so there is no need to use electrolytic capacitors with large capacitance, large volume and short life. Film capacitors with small capacitance and long life can be used. In addition, the secondary side of the transformer adopts a Y-type connection, and the output phase difference between the three phases is 120 degrees. The three-phase currents are staggered at 120 degrees, and the three-phase currents can be completely cancelled. The output DC current, so no large output capacitor is required. Overall, high power, high efficiency, small volume and long life are achieved.

[0042] In summary, according to an embodiment of the present invention, a wide-range output three-phase isolated bidirectional single-stage converter includes: a three-phase AC side voltage port, a DC voltage port, first to third AC side circuit units, first to third transformers and a wide voltage output unit, wherein the three-phase AC port includes first to sixth ports; the DC voltage port includes seventh port and eighth port; the first transformer includes a first winding and a second winding, the first winding is provided with a first center tap, the first center tap is connected to the first end of the first AC side circuit unit, the two ends of the first winding are respectively connected to the second end and the third end of the first AC side circuit unit, and the two ends of the second winding are respectively connected to the first bridge arm midpoint and the second bridge arm midpoint of the wide voltage output unit; the second transformer includes a third winding and a fourth winding, the third winding is provided with a second center tap, the second center tap is connected to the first end of the second AC side circuit unit, and the third winding is provided with a second center tap. The two ends are respectively connected to the second end and the third end of the second AC side circuit unit, and the two ends of the fourth winding are respectively connected to the third bridge arm midpoint and the second bridge arm midpoint of the wide voltage output unit; the third transformer includes a fifth winding and a sixth winding, the fifth winding is provided with a third center tap, the third center tap is connected to the first end of the third AC side circuit unit, the two ends of the fifth winding are respectively connected to the second end and the third end of the third AC side circuit unit, and the two ends of the fifth winding are respectively connected to the fourth bridge arm midpoint and the second bridge arm midpoint of the wide voltage output unit; the fourth end and the fifth end of the first AC side circuit unit are respectively connected to the first port and the second port; the fourth end and the fifth end of the second AC side circuit unit are respectively connected to the third port and the fourth port; the fourth end and the fifth end of the third AC side circuit unit are respectively connected to the fifth end and the sixth port; the two ends of the wide voltage output unit are respectively connected to the seventh port and the eighth port. Thus, only one-stage power conversion is included, which can greatly improve the working efficiency and accuracy of the converter, and a T-type three-level structure is adopted on the DC side, which can use fewer switch tubes to achieve wide range output.

[0043] Corresponding to the structure of the wide-range output three-phase isolated bidirectional single-stage converter of the above embodiment, in one embodiment of the present invention, the converter can be controlled by the following steps:

[0044] Taking a certain phase power supply corresponding to the first port A and the second port B as an example, the other two phases are similar. When the wide-range output three-phase isolated bidirectional single-stage converter operates in the inverter mode, a corresponding first drive signal with a duty cycle of 50% is sent to the driving end of the first to fourth switch tubes to control only one of the two switch tubes in the same bridge arm in the first full-bridge circuit subunit to be in the on state, and a second drive signal is sent to the driving end of the thirteenth switch tube and the fourteenth switch tube to control only one of the thirteenth switch tube and the fourteenth switch tube to be in the on state, and a second drive signal is sent to the driving end of the nineteenth switch tube, the twentieth switch tube, the twenty-fifth switch tube and the twenty-sixth switch tube. a third drive signal is input to the driving end of the nineteenth switch tube, wherein the duty ratio of the third drive signal input to the driving end of the twenty-fifth switch tube is the same as the duty ratio of the third drive signal input to the driving end of the twenty-fifth switch tube, the driving of the nineteenth switch tube and the twenty-th switch tube are complementary, the driving of the twenty-fifth switch tube and the twenty-sixth switch tube are complementary, the third drive signal input to the driving end of the twenty-fifth switch tube lags behind the third drive signal input to the driving end of the nineteenth switch tube, and the third drive signal input to the driving end of the nineteenth switch tube is ahead of the first drive signal input to the driving end of the first switch tube;

[0045] When the wide-range output three-phase isolated bidirectional single-stage converter operates in the rectification mode, a corresponding fourth driving signal with a duty cycle of 50% is sent to the driving ends of the first to fourth switch tubes to control only one of the two switch tubes in the same bridge arm in the first full-bridge circuit subunit to be in the on state, and a fifth driving signal is sent to the driving ends of the thirteenth switch tube and the fourteenth switch tube according to the AC terminal voltage to control the thirteenth switch tube and the fourteenth switch tube to be turned on or off, wherein when the AC terminal voltage is positive, the thirteenth switch tube is controlled to be turned off, and the fourteenth switch tube is controlled to be turned on or off, and when the AC terminal voltage is negative, the fourteenth switch tube is controlled to be turned off, and the thirteenth switch tube is controlled to be turned on or off. The switch tube is turned on or off, and a sixth drive signal is input to the driving ends of the nineteenth switch tube, the twentieth switch tube, the twenty-fifth switch tube and the twenty-sixth switch tube, wherein the duty cycle of the sixth drive signal input to the driving end of the nineteenth switch tube is the same as the duty cycle of the sixth drive signal input to the driving end of the twenty-fifth switch tube, the driving of the nineteenth switch tube and the twentieth switch tube are complementary, the driving of the twenty-fifth switch tube and the twenty-sixth switch tube are complementary, the sixth drive signal input to the driving end of the twenty-fifth switch tube is ahead of the sixth drive signal input to the driving end of the nineteenth switch tube, and the sixth drive signal input to the driving end of the nineteenth switch tube lags behind the fourth drive signal input to the driving end of the first switch tube.

[0046] It should be noted that, as a possible implementation method, Figure 2 As shown, the AC side voltage (v g1 、v g2 and v g3 ) and AC side current, collect DC side voltage v0 and DC side current on the DC side, and when receiving rectification or inversion instructions, a double closed-loop control strategy can be used to obtain the driving signal of each switch tube. Specifically, a set of output voltage loops are used to calculate the first error value I according to the AC side voltage, AC side current and DC side voltage ac_ref , which includes the DC link voltage v0 and the reference voltage V dc_ref The first error value I ac_ref Provided to each input current loop (including input current loop 1, input current loop 2 and input current loop 3) respectively, each input current loop is based on the corresponding AC side voltage, the phase θ provided by the phase-locked loop PLL and the first error value I ac_ref Perform calculation to calculate the corresponding second error value D f , where taking input current loop 1 as an example, in input current loop 1, we can first calculate the AC side voltage v g1The abc-dq coordinate transformation is performed with the phase θ provided by the phase-locked loop PLL, and then the transformation result is compared with the first error value Iac_ref, and then the comparison is input into the PI controller to output the corresponding second error value Df. The second error value Df and the output of the phase-locked loop PLL are input into the duty cycle adjuster (modulation) for duty cycle adjustment, and the corresponding switch tube drive signal is output, wherein the output of the duty cycle adjuster (modulation) corresponding to the input current loop 1 is the drive signal of the first switch tube S1, the second switch tube S2, the third switch tube S3, the fourth switch tube S4, the thirteenth switch tube S13, the fourteenth switch tube S14, the nineteenth switch tube S19, the twentieth switch tube S20, the twenty-fifth switch tube S25 and the twenty-sixth switch tube S26, and the output of the duty cycle adjuster (modulation) corresponding to the input current loop 2 is the drive signal of the fifth switch tube S5, the sixth switch tube S6, the seventh switch tube S7, the eighth switch tube S8, the eighth switch tube S9, the eighth switch tube S10, the eighth switch tube S11, the eighth switch tube S12, the eighth switch tube S13, the eighth switch tube S14, the eighth switch tube S15, the eighth switch tube S16, the eighth switch tube S17, the eighth switch tube S18, the eighth switch tube S19, the eighth switch tube S20, the eighth switch tube S21, the eighth switch tube S22, the eighth switch tube S23, the eighth switch tube S24, the eighth switch tube S25, the eighth switch tube S26, and the eighth switch tube S27. The output of the duty cycle adjuster (modulation) corresponding to the input current loop 3 is the driving signal of the ninth switch tube S9, the tenth switch tube S10, the eleventh switch tube S11, the twelfth switch tube S12, the seventeenth switch tube S17, the eighteenth switch tube S18, the twenty-third switch tube S23, the twenty-fourth switch tube S24, the twenty-ninth switch tube S29 and the thirtieth switch tube S30, and the driving signal is sent to the driving end of each switch tube to realize rectification or inversion.

[0047] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. "Multiple" means two or more, unless otherwise clearly and specifically defined.

[0048] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0050] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0051] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0052] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0053] In addition, each functional unit in each embodiment of the present invention may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0054] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A wide-range output three-phase isolated bidirectional single-stage converter, characterized in that: include: A three-phase AC side voltage port, a DC voltage port, first to third AC side circuit units, first to third transformers and a wide voltage output unit, wherein: The three-phase AC port includes first to sixth ports; The DC voltage port includes a seventh port and an eighth port; The first transformer includes a first winding and a second winding, the first winding is provided with a first center tap, the first center tap is connected to the first end of the first AC side circuit unit, the two ends of the first winding are respectively connected to the second end and the third end of the first AC side circuit unit, and the two ends of the second winding are respectively connected to the first bridge arm midpoint and the second bridge arm midpoint of the wide voltage output unit; the second transformer includes a third winding and a fourth winding, the third winding is provided with a second center tap, the second center tap is connected to the first end of the second AC side circuit unit, the two ends of the third winding are respectively connected to the second end and the third end of the second AC side circuit unit, and the two ends of the fourth winding are respectively connected to the third bridge arm midpoint and the second bridge arm midpoint of the wide voltage output unit; the third transformer includes a fifth winding and a sixth winding, the fifth winding is provided with a third center tap, the third center tap is connected to the first end of the third AC side circuit unit, the two ends of the fifth winding are respectively connected to the second end and the third end of the third AC side circuit unit, and the two ends of the fifth winding are respectively connected to the fourth bridge arm midpoint and the second bridge arm midpoint of the wide voltage output unit; The fourth end and the fifth end of the first AC side circuit unit are connected to the first port and the second port respectively; the fourth end and the fifth end of the second AC side circuit unit are connected to the third port and the fourth port respectively; the fourth end and the fifth end of the third AC side circuit unit are connected to the fifth end and the sixth port respectively; Two ends of the wide voltage output unit are connected to the seventh port and the eighth port respectively.

2. The wide-range output three-phase isolated bidirectional single-stage converter according to claim 1, characterized in that: The first AC side circuit unit includes: a first filter circuit subunit, a first full-bridge circuit subunit, a first half-bridge circuit subunit, a first coupling circuit subunit and a first bus capacitor, wherein one end of the first filter circuit subunit is connected to the first port, the other end of the first filter circuit subunit is connected to the first center tap, the midpoints of the two bridge arms of the first full-bridge circuit subunit are respectively connected to the two ends of the first winding through the first coupling circuit subunit, the two ends of the first full-bridge circuit subunit are respectively connected to the two ends of the first half-bridge circuit subunit, the midpoint of the bridge arm of the first half-bridge circuit subunit is connected to the second port, and the two ends of the first half-bridge circuit subunit are also connected to the first bus capacitor; The second AC side circuit unit includes: a second filter circuit subunit, a second full-bridge circuit subunit, a second half-bridge circuit subunit, a second coupling circuit subunit and a second bus capacitor, wherein one end of the second filter circuit subunit is connected to the third port, the other end of the second filter circuit subunit is connected to the second center tap, the midpoints of the two bridge arms of the second full-bridge circuit subunit are respectively connected to the two ends of the third winding through the second coupling circuit subunit, the two ends of the second full-bridge circuit subunit are respectively connected to the two ends of the second half-bridge circuit subunit, the midpoint of the bridge arm of the second half-bridge circuit subunit is connected to the fourth port, and the two ends of the second half-bridge circuit subunit are also connected to the second bus capacitor; The third AC side circuit unit includes: a third filter circuit subunit, a third full-bridge circuit subunit, a third half-bridge circuit subunit, a third coupling circuit subunit and a third bus capacitor, wherein one end of the third filter circuit subunit is connected to the fifth port, the other end of the third filter circuit subunit is connected to the third center tap, the midpoints of the two bridge arms of the third full-bridge circuit subunit are respectively connected to the two ends of the fifth winding through the third coupling circuit subunit, the two ends of the third full-bridge circuit subunit are respectively connected to the two ends of the third half-bridge circuit subunit, the midpoint of the bridge arm of the third half-bridge circuit subunit is connected to the sixth port, and the two ends of the third half-bridge circuit subunit are also connected to the third bus capacitor.

3. The wide-range output three-phase isolated bidirectional single-stage converter according to claim 2, characterized in that: The first full-bridge circuit subunit comprises: a first switch tube and a second switch tube connected in series and a third switch tube and a fourth switch tube connected in series, wherein the second end of the first switch tube is connected to the first end of the second switch tube, and the connection point between the first switch tube and the second switch tube is a midpoint of a bridge arm of the first full-bridge circuit subunit; the second end of the third switch tube is connected to the first end of the fourth switch tube, and the connection point between the third switch tube and the fourth switch tube is another midpoint of the bridge arm of the first full-bridge circuit subunit, the first end of the third switch tube is connected to the first end of the first switch tube, and the second end of the fourth switch tube is connected to the second end of the second switch tube; The second full-bridge circuit subunit includes: a fifth switch tube and a sixth switch tube connected in series, and a seventh switch tube and an eighth switch tube connected in series, wherein the second end of the fifth switch tube is connected to the first end of the sixth switch tube, and the connection point between the fifth switch tube and the sixth switch tube is a midpoint of a bridge arm of the second full-bridge circuit subunit; the second end of the seventh switch tube is connected to the first end of the eighth switch tube, and the connection point between the seventh switch tube and the eighth switch tube is another midpoint of the bridge arm of the second full-bridge circuit subunit, the first end of the seventh switch tube is connected to the first end of the fifth switch tube, and the second end of the eighth switch tube is connected to the second end of the sixth switch tube; The third full-bridge circuit sub-unit includes: a ninth switch tube and a tenth switch tube connected in series, and an eleventh switch tube and a twelfth switch tube connected in series, wherein the second end of the ninth switch tube is connected to the first end of the tenth switch tube, and the connection point between the ninth switch tube and the tenth switch tube is a midpoint of a bridge arm of the third full-bridge circuit sub-unit; the second end of the eleventh switch tube is connected to the first end of the twelfth switch tube, and the connection point between the eleventh switch tube and the twelfth switch tube is another midpoint of the bridge arm of the third full-bridge circuit sub-unit, the first end of the eleventh switch tube is connected to the first end of the ninth switch tube, and the second end of the twelfth switch tube is connected to the second end of the tenth switch tube.

4. The wide-range output three-phase isolated bidirectional single-stage converter according to claim 3, characterized in that: The first half-bridge circuit subunit comprises: a thirteenth switch tube and a fourteenth switch tube connected in series, wherein the second end of the thirteenth switch tube is connected to the first end of the fourteenth switch tube, the connection point between the thirteenth switch tube and the fourteenth switch tube is the midpoint of the bridge arm of the first half-bridge circuit subunit, the first end of the thirteenth switch tube is connected to the first end of the third switch tube, and the second end of the fourteenth switch tube is connected to the second end of the fourth switch tube; The second half-bridge circuit subunit comprises: a fifteenth switch tube and a sixteenth switch tube connected in series, wherein the second end of the fifteenth switch tube is connected to the first end of the sixteenth switch tube, the connection point between the fifteenth switch tube and the sixteenth switch tube is the midpoint of the bridge arm of the second half-bridge circuit subunit, the first end of the fifteenth switch tube is connected to the first end of the seventh switch tube, and the second end of the sixteenth switch tube is connected to the second end of the eighth switch tube; The third half-bridge circuit sub-unit includes: a seventeenth switch tube and an eighteenth switch tube connected in series, wherein the second end of the seventeenth switch tube is connected to the first end of the eighteenth switch tube, the connection point between the seventeenth switch tube and the eighteenth switch tube is the midpoint of the bridge arm of the third half-bridge circuit sub-unit, the first end of the seventeenth switch tube is connected to the first end of the eleventh switch tube, and the second end of the eighteenth switch tube is connected to the second end of the twelfth switch tube.

5. The wide-range output three-phase isolated bidirectional single-stage converter according to claim 3, characterized in that: The first coupling circuit subunit includes: a first coupling inductor and a second coupling inductor, wherein one end of the first coupling inductor is connected to a midpoint of a bridge arm of the first full-bridge circuit subunit, and the other end of the first coupling inductor is connected to one end of the first winding; one end of the second coupling inductor is connected to the midpoint of another bridge arm of the first full-bridge circuit subunit, and the other end of the second coupling inductor is connected to the other end of the first winding; The second coupling circuit subunit comprises: a third coupling inductor and a fourth coupling inductor, wherein one end of the third coupling inductor is connected to a midpoint of a bridge arm of the second full-bridge circuit subunit, and the other end of the third coupling inductor is connected to one end of the third winding; one end of the fourth coupling inductor is connected to the midpoint of another bridge arm of the second full-bridge circuit subunit, and the other end of the fourth coupling inductor is connected to the other end of the third winding; The third coupling circuit subunit includes: a fifth coupling inductor and a sixth coupling inductor, wherein one end of the fifth coupling inductor is connected to a midpoint of a bridge arm of the third full-bridge circuit subunit, and the other end of the fifth coupling inductor is connected to one end of the fifth winding; one end of the sixth coupling inductor is connected to the midpoint of another bridge arm of the third full-bridge circuit subunit, and the other end of the sixth coupling inductor is connected to the other end of the fifth winding.

6. The wide-range output three-phase isolated bidirectional single-stage converter according to claim 5, characterized in that: The first filter circuit subunit includes: a first filter inductor and a first resistor, wherein one end of the first filter inductor is connected to the first port, one end of the first resistor is connected to the other end of the first filter inductor, and the other end of the first resistor is connected to the first center tap; The second filter circuit subunit comprises: a second filter inductor and a second resistor, wherein one end of the second filter inductor is connected to the third port, one end of the second resistor is connected to the other end of the second filter inductor, and the other end of the second resistor is connected to the second center tap; The third filter circuit subunit includes: a third filter inductor and a third resistor, wherein one end of the third filter inductor is connected to the fifth port, one end of the third resistor is connected to the other end of the third filter inductor, and the other end of the third resistor is connected to the third center tap.

7. The wide-range output three-phase isolated bidirectional single-stage converter according to claim 6, characterized in that: The wide voltage output unit comprises: A nineteenth switch tube and a twentieth switch tube connected in series, wherein the second end of the nineteenth switch tube is connected to the first end of the twentieth switch tube, and the connection point between the nineteenth switch tube and the twentieth switch tube is the midpoint of the first bridge arm of the wide voltage output unit; a twenty-first switch tube and a twenty-second switch tube connected in series, wherein the second end of the twenty-first switch tube is connected to the first end of the twenty-second switch tube, the first end of the twenty-first switch tube is connected to the first end of the nineteenth switch tube, the second end of the twenty-second switch tube is connected to the second end of the twenty-th switch tube, and the connection point between the twenty-first switch tube and the twenty-second switch tube is the midpoint of the third bridge arm of the wide voltage output unit; a twenty-third switch tube and a twenty-fourth switch tube connected in series, wherein the second end of the twenty-third switch tube is connected to the first end of the twenty-fourth switch tube, the first end of the twenty-third switch tube is connected to the first end of the twenty-first switch tube, the second end of the twenty-fourth switch tube is connected to the second end of the twenty-second switch tube, and the connection point between the twenty-third switch tube and the twenty-fourth switch tube is the fourth bridge arm midpoint of the wide voltage output unit; a first capacitor and a second capacitor connected in series, wherein one end of the first capacitor is connected to one end of the second capacitor, the other end of the first capacitor is respectively connected to the first end of the twenty-third switch tube and the seventh port, the other end of the second capacitor is respectively connected to the second end of the twenty-fourth switch tube and the eighth port, and the connection point between the first capacitor and the second capacitor is the midpoint of the second bridge arm of the wide voltage output unit; a twenty-fifth switch tube and a twenty-sixth switch tube connected in series, wherein the first end of the twenty-fifth switch tube is connected to the midpoint of the first bridge arm of the wide voltage output unit, the second end of the twenty-fifth switch tube is connected to the second end of the twenty-sixth switch tube, and the first end of the twenty-sixth switch tube is connected to the midpoint of the second bridge arm of the wide voltage output unit; a twenty-seventh switch tube and a twenty-eighth switch tube connected in series, wherein the first end of the twenty-seventh switch tube is connected to the midpoint of the third bridge arm of the wide voltage output unit, the second end of the twenty-seventh switch tube is connected to the second end of the twenty-eighth switch tube, and the first end of the twenty-eighth switch tube is connected to the midpoint of the second bridge arm of the wide voltage output unit; The twenty-ninth switch tube and the thirtieth switch tube are connected in series, the first end of the twenty-ninth switch tube is connected to the midpoint of the fourth bridge arm of the wide voltage output unit, the second end of the twenty-ninth switch tube is connected to the second end of the thirtieth switch tube, and the first end of the thirtieth switch tube is connected to the midpoint of the second bridge arm of the wide voltage output unit.

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