Three-phase one-stage insulated bidirectional converter and its control method

Abstract

The present invention provides a three-phase one-stage insulated bidirectional converter and a control method thereof. The bidirectional converter includes a three-phase AC voltage port, a DC voltage port, first to sixth full-bridge circuit units, first to third half-bridge circuit units, first to third phase-shift inductor units, first to third transformers, and first to third filter capacitors. The first full-bridge circuit unit is interconnected with both ends of the first half-bridge circuit unit respectively. The third full-bridge circuit unit is interconnected with both ends of the second half-bridge circuit unit respectively. The fifth full-bridge circuit unit is interconnected with both ends of the third half-bridge circuit unit respectively. The first half-bridge circuit unit is further interconnected with both ends of the first filter capacitor. The midpoint of the bridge arm of the first half-bridge circuit unit is interconnected with the second port. The midpoint of the bridge arm of the second half-bridge circuit unit is interconnected with the fourth port. The midpoint of the bridge arm of the third half-bridge circuit unit is interconnected with the sixth port. Thereby, the operation efficiency and accuracy of the converter are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics, and more specifically, to a three-phase single-stage isolated bidirectional converter and a control method thereof.

Background Art

[0002] In related technologies, a three-phase single-stage isolated AC / DC bidirectional converter has low operating efficiency and accuracy, thus greatly reducing the reliability of the system.

Summary of the Invention

[0003] In order to solve the above technical problems, the present invention provides a three-phase single-stage isolated bidirectional converter that includes only a single-stage power conversion, can greatly improve the operating efficiency and accuracy of the converter, and enhance the reliability of the system.

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

[0005] A three-phase AC voltage port, a DC voltage port, first to sixth full-bridge circuit units, first to third half-bridge circuit units, first to third phase-shift inductor units, first to third transformers, and first to third filter capacitors, wherein the three-phase AC voltage port includes first to sixth ports, the DC voltage port includes a seventh port and an eighth port, the first transformer includes a first coil and a second coil, the first coil is provided with a first center tap, the first center tap is interconnected with the first port, both ends of the first coil are interconnected with the midpoints of two bridge arms of the first full-bridge circuit unit via the first phase-shift inductor unit respectively, both ends of the second coil are interconnected with the midpoints of two bridge arms of the second full-bridge circuit unit respectively; the second transformer includes a third coil and a fourth coil, the third coil is provided with a second center tap, the second center tap is interconnected with the third port, both ends of the third coil are interconnected with the midpoints of two bridge arms of the third full-bridge circuit unit via the second phase-shift inductor unit respectively, both ends of the fourth coil are interconnected with the midpoints of two bridge arms of the fourth full-bridge circuit unit respectively; the third transformer includes a fifth coil and a sixth coil, the fifth coil is provided with a third center tap, the third center tap is interconnected with the fifth port, both ends of the fifth coil are interconnected with the midpoints of two bridge arms of the fifth full-bridge circuit unit via the third phase-shift inductor unit respectively, both ends of the sixth coil are interconnected with the midpoints of two bridge arms of the sixth full-bridge circuit unit respectively; both ends of the first full-bridge circuit unit are interconnected with both ends of the first half-bridge circuit unit respectively, both ends of the third full-bridge circuit unit are interconnected with both ends of the second half-bridge circuit unit respectively, both ends of the fifth full-bridge circuit unit are interconnected with both ends of the third half-bridge circuit unit respectively, and both ends of the first half-bridge circuit unit are further interconnected with both ends of the first filter capacitor.The midpoint of the bridge arm of the first half-bridge circuit unit is interconnected with the second port, both ends of the second half-bridge circuit unit are further interconnected with both ends of the second filter capacitor, the midpoint of the bridge arm of the second half-bridge circuit unit is interconnected with the fourth port, both ends of the third half-bridge circuit unit are further interconnected with both ends of the third filter capacitor, the midpoint of the bridge arm of the third half-bridge circuit unit is interconnected with the sixth port, both ends of the second full-bridge circuit unit are respectively interconnected with the seventh port and the eighth port, both ends of the fourth full-bridge circuit unit are respectively interconnected with the seventh port and the eighth port, and both ends of the sixth full-bridge circuit unit are respectively interconnected with the seventh port and the eighth port. A three-phase one-stage insulated bidirectional converter is characterized by this.

[0006] The first full-bridge circuit unit 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. The first end of the first switch tube is interconnected with the first end of the second switch tube. The connection point between the first switch tube and the second switch tube is the midpoint of one bridge arm of the first full-bridge circuit unit. The first end of the third switch tube is interconnected with the first end of the fourth switch tube. The connection point between the third switch tube and the fourth switch tube is the midpoint of the other bridge arm of the first full-bridge circuit unit. The second end of the third switch tube is interconnected with the second end of the first switch tube. The second end of the fourth switch tube is interconnected with the second end of the second switch tube. The third full-bridge circuit unit 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. The first end of the fifth switch tube is interconnected with the first end of the sixth switch tube. The connection point between the fifth switch tube and the sixth switch tube is the midpoint of one bridge arm of the third full-bridge circuit unit. The first end of the seventh switch tube is interconnected with the first end of the eighth switch tube. The connection point between the seventh switch tube and the eighth switch tube is the midpoint of the other bridge arm of the third full-bridge circuit unit. The second end of the seventh switch tube is interconnected with the second end of the fifth switch tube. The second end of the eighth switch tube is interconnected with the second end of the sixth switch tube. The fifth full-bridge circuit 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. The first end of the ninth switch tube is interconnected with the first end of the tenth switch tube. The connection point between the ninth switch tube and the tenth switch tube is the midpoint of one bridge arm of the fifth full-bridge circuit unit. The first end of the eleventh switch tube is interconnected with the first end of the twelfth switch tube. The connection point between the eleventh switch tube and the twelfth switch tube is the midpoint of the other bridge arm of the fifth full-bridge circuit unit. The second end of the eleventh switch tube is interconnected with the second end of the ninth switch tube. The second end of the twelfth switch tube is interconnected with the second end of the tenth switch tube.

[0007] The first half-bridge circuit unit includes a 13th switch tube and a 14th switch tube connected in series. The first end of the 13th switch tube is interconnected with the first end of the 14th switch tube. The connection point between the 13th switch tube and the 14th switch tube is the midpoint of the bridge arm of the first half-bridge circuit unit. The second end of the 13th switch tube is interconnected with the second end of the 3rd switch tube. The second end of the 14th switch tube is interconnected with the second end of the 4th switch tube. The second half-bridge circuit unit includes a 15th switch tube and a 16th switch tube connected in series. The first end of the 15th switch tube is interconnected with the first end of the 16th switch tube. The connection point between the 15th switch tube and the 16th switch tube is the midpoint of the bridge arm of the second half-bridge circuit unit. The second end of the 15th switch tube is interconnected with the second end of the 7th switch tube. The second end of the 16th switch tube is interconnected with the second end of the 8th switch tube. The third half-bridge circuit unit includes a 17th switch tube and a 18th switch tube connected in series. The first end of the 17th switch tube is interconnected with the first end of the 18th switch tube. The connection point between the 17th switch tube and the 18th switch tube is the midpoint of the bridge arm of the third half-bridge circuit unit. The second end of the 17th switch tube is interconnected with the second end of the 11th switch tube. The second end of the 18th switch tube is interconnected with the second end of the 12th switch tube.

[0008] The first phase shift inductor unit includes a first phase shift inductor and a second phase shift inductor. One end of the first phase shift inductor is interconnected with the midpoint of one bridge arm of the first full bridge circuit unit, the other end of the first phase shift inductor is interconnected with one end of the first coil, one end of the second phase shift inductor is interconnected with the midpoint of the other bridge arm of the first full bridge circuit unit, and the other end of the second phase shift inductor is interconnected with the other end of the first coil. The second phase shift inductor unit includes a third phase shift inductor and a fourth phase shift inductor. One end of the third phase shift inductor is interconnected with the midpoint of one bridge arm of the third full bridge circuit unit, the other end of the third phase shift inductor is interconnected with one end of the third coil, one end of the fourth phase shift inductor is interconnected with the midpoint of the other bridge arm of the third full bridge circuit unit, and the other end of the fourth phase shift inductor is interconnected with the other end of the third coil. The third phase shift inductor unit includes a fifth phase shift inductor and a sixth phase shift inductor. One end of the fifth phase shift inductor is interconnected with the midpoint of one bridge arm of the fifth full bridge circuit unit, the other end of the fifth phase shift inductor is interconnected with one end of the fifth coil, one end of the sixth phase shift inductor is interconnected with the midpoint of the other bridge arm of the fifth full bridge circuit unit, and the other end of the sixth phase shift inductor is interconnected with the other end of the fifth coil.

[0009] The second full-bridge circuit unit includes a 19th switch tube and a 20th switch tube connected in series, and a 21st switch tube and a 22nd switch tube connected in series. The first end of the 19th switch tube is interconnected with the first end of the 20th switch tube. The connection point between the 19th switch tube and the 20th switch tube is the midpoint of one bridge arm of the second full-bridge circuit unit. The first end of the 21st switch tube is interconnected with the first end of the 22nd switch tube. The connection point between the 21st switch tube and the 22nd switch tube is the midpoint of the other bridge arm of the second full-bridge circuit unit. The second end of the 21st switch tube is interconnected with the second end of the 19th switch tube. The second end of the 22nd switch tube is interconnected with the second end of the 20th switch tube. The fourth full-bridge circuit unit includes a 23rd switch tube and a 24th switch tube connected in series, and a 25th switch tube and a 26th switch tube connected in series. The first end of the 23rd switch tube is interconnected with the first end of the 24th switch tube. The connection point between the 23rd switch tube and the 24th switch tube is the midpoint of one bridge arm of the fourth full-bridge circuit unit. The first end of the 25th switch tube is interconnected with the first end of the 26th switch tube. The connection point between the 25th switch tube and the 26th switch tube is the midpoint of the other bridge arm of the fourth full-bridge circuit unit. The second end of the 25th switch tube is interconnected with the second end of the 23rd switch tube. The second end of the 26th switch tube is interconnected with the second end of the 24th switch tube. The sixth full-bridge circuit unit includes a 27th switch tube and a 28th switch tube connected in series, and a 29th switch tube and a 30th switch tube connected in series. The first end of the 27th switch tube is interconnected with the first end of the 28th switch tube. The connection point between the 27th switch tube and the 28th switch tube is the midpoint of one bridge arm of the sixth full-bridge circuit unit. The first end of the 29th switch tube is interconnected with the first end of the 30th switch tube. The connection point between the 29th switch tube and the 30th switch tube is the midpoint of the other bridge arm of the sixth full-bridge circuit unit. The second end of the 29th switch tube is interconnected with the second end of the 27th switch tube,The second end of the 30th switch tube is interconnected with the second end of the 28th switch tube.

[0010] A control method for a three-phase one-stage insulated bidirectional converter, the control method includes: when receiving a rectification or inversion control command, collecting the DC current of the DC voltage port, and collecting the three-phase AC voltage and three-phase AC current of the three-phase AC voltage port; adopting a double closed-loop control method, generating a drive signal with a duty ratio of 50% based on the DC current, the three-phase AC voltage, and the three-phase AC current, and sending the drive signal to the drive ends of the first to 13th switch tubes to control the operation of the three-phase one-stage insulated bidirectional converter in the rectification mode or the inversion mode.

[0011] Specifically, when the three-phase one-stage insulated bidirectional converter operates in the rectification mode, the controller controls such that the drive signal corresponding to the first full-bridge circuit unit precedes the drive signal corresponding to the second full-bridge circuit unit, the drive signal corresponding to the third full-bridge circuit unit precedes the drive signal corresponding to the fourth full-bridge circuit unit, and the drive signal corresponding to the fifth full-bridge circuit unit precedes the drive signal corresponding to the sixth full-bridge circuit unit. The double closed-loop control method is adopted and used to calculate the phase angle by which the drive signal corresponding to the first full-bridge circuit unit precedes the drive signal corresponding to the second full-bridge circuit unit, the phase angle by which the drive signal corresponding to the third full-bridge circuit unit precedes the drive signal corresponding to the fourth full-bridge circuit unit, and the phase angle by which the drive signal corresponding to the fifth full-bridge circuit unit precedes the drive signal corresponding to the sixth full-bridge circuit unit, respectively.

[0012] When the three-phase one-stage insulated bidirectional converter operates in the inversion mode, control is performed such that the drive signal corresponding to the first full-bridge circuit unit lags behind the drive signal corresponding to the second full-bridge circuit unit, the drive signal corresponding to the third full-bridge circuit unit lags behind the drive signal corresponding to the fourth full-bridge circuit unit, and the drive signal corresponding to the fifth full-bridge circuit unit lags behind the drive signal corresponding to the sixth full-bridge circuit unit. A double closed-loop control method is adopted, and the phase angle by which the drive signal corresponding to the first full-bridge circuit unit lags behind the drive signal corresponding to the second full-bridge circuit unit, the phase angle by which the drive signal corresponding to the third full-bridge circuit unit lags behind the drive signal corresponding to the fourth full-bridge circuit unit, and the phase angle by which the drive signal corresponding to the fifth full-bridge circuit unit lags behind the drive signal corresponding to the sixth full-bridge circuit unit are respectively calculated.

Advantages of the Invention

[0013] The present invention includes only one-stage power conversion, and can greatly improve the operating efficiency and accuracy of the converter and enhance the reliability of the system.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0015] Hereinafter, in conjunction with the accompanying drawings in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Naturally, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts belong to the protection scope of the present invention.

[0016] Figure 1 is a structural diagram of a three-phase one-stage insulated bidirectional converter according to an embodiment of the present invention.

[0017] As shown in Figure 1, the three-phase one-stage insulated bidirectional converter according to the embodiment of the present invention may include a three-phase AC voltage port 100, a DC voltage port 200, first to sixth full-bridge circuit units 300 to 800, first to third half-bridge circuit units 900 to 1100, first to third phase-shift inductor units 1200 to 1400, first to third transformers 1500 to 1700, and first to third filter capacitors 1800 to 2000.

[0018] Among them, the three-phase AC voltage port 100 includes the first to sixth ports, and the DC voltage port 200 includes the seventh port and the eighth port. The first transformer 1500 includes a first coil 1510 and a second coil 1520. A first center tap is provided on the first coil 1510. The first center tap is interconnected with the first port. Both ends of the first coil 1510 are respectively interconnected with the midpoints of two bridge arms of the first full-bridge circuit unit 300 through the first phase-shifting inductor unit 1200. Both ends of the second coil 1520 are respectively interconnected with the midpoints of two bridge arms of the second full-bridge circuit unit 400. The second transformer 1600 includes a third coil 1610 and a fourth coil 1620. A second center tap is provided on the third coil 1610. The second center tap is interconnected with the third port. Both ends of the third coil 1610 are respectively interconnected with the midpoints of two bridge arms of the third full-bridge circuit unit 500 through the second phase-shifting inductor unit 1300. Both ends of the fourth coil 1620 are respectively interconnected with the midpoints of two bridge arms of the fourth full-bridge circuit unit 600. The third transformer 1700 includes a fifth coil 1710 and a sixth coil 1720. A third center tap is provided on the fifth coil 1710. The third center tap is interconnected with the fifth port. Both ends of the fifth coil 1710 are respectively interconnected with the midpoints of two bridge arms of the fifth full-bridge circuit unit 700 through the third phase-shifting inductor unit 1400. Both ends of the sixth coil 1720 are respectively interconnected with the midpoints of two bridge arms of the sixth full-bridge circuit unit 800. Both ends of the first full-bridge circuit unit 300 are respectively interconnected with both ends of the first half-bridge circuit unit 900. Both ends of the third full-bridge circuit unit 500 are respectively interconnected with both ends of the second half-bridge circuit unit 1000. Both ends of the fifth full-bridge circuit unit 700 are respectively interconnected with both ends of the third half-bridge circuit unit 1100.Both ends of the first half-bridge circuit unit 900 are further interconnected with both ends of the first filter capacitor 1800. The midpoint of the bridge arm of the first half-bridge circuit unit 900 is interconnected with the second port. Both ends of the second half-bridge circuit unit 1000 are further interconnected with both ends of the second filter capacitor 1900. The midpoint of the bridge arm of the second half-bridge circuit unit 1000 is interconnected with the fourth port. Both ends of the third half-bridge circuit unit 1100 are further interconnected with both ends of the third filter capacitor 2000. The midpoint of the bridge arm of the third half-bridge circuit unit 1100 is interconnected with the sixth port. Both ends of the second full-bridge circuit unit 400 are interconnected with the seventh port and the eighth port respectively. Both ends of the fourth full-bridge circuit unit 600 are interconnected with the seventh port and the eighth port respectively. Both ends of the sixth full-bridge circuit unit 800 are interconnected with the seventh port and the eighth port respectively. Among them, both ends of the second full-bridge circuit unit 400, the fourth full-bridge circuit unit 600, and the sixth full-bridge circuit unit 800 may be interconnected with the seventh port and the eighth port respectively via corresponding capacitors.

[0019] Among them, as shown in FIG. 1, the first full-bridge circuit unit 300, the first half-bridge circuit unit 900, the second full-bridge circuit unit 400, the first phase shift inductor unit 1200, and the first transformer 1500 may be integrated into the first module. The third full-bridge circuit unit 500, the second half-bridge circuit unit 1000, the fourth full-bridge circuit unit 600, the second phase shift inductor unit 1300, and the second transformer 1600 may be integrated into the second module. The fifth full-bridge circuit unit 700, the third half-bridge circuit unit 1100, the sixth full-bridge circuit unit 800, the third phase shift inductor unit 1400, and the third transformer 1700 may be integrated into the third module.

[0020] Based on one embodiment of the present invention, as shown in FIG. 1, the first full-bridge circuit unit 300 may include 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. The first end of the first switch tube S1 is interconnected with the first end of the second switch tube S2, and the connection point between the first switch tube S1 and the second switch tube S2 is the midpoint of one bridge arm of the first full-bridge circuit unit 300. The first end of the third switch tube S3 is interconnected with the first end of the fourth switch tube S4, and the connection point between the third switch tube S3 and the fourth switch tube S4 is the midpoint of the other bridge arm of the first full-bridge circuit unit 300. The second end of the third switch tube S3 is interconnected with the second end of the first switch tube S1, and the second end of the fourth switch tube S4 is interconnected with the second end of the second switch tube S2. The third full-bridge circuit unit 500 may include 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. The first end of the fifth switch tube S5 is interconnected with the first end of the sixth switch tube S6, and the connection point between the fifth switch tube S5 and the sixth switch tube S6 is the midpoint of one bridge arm of the third full-bridge circuit unit 500. The first end of the seventh switch tube S7 is interconnected with the first end of the eighth switch tube S8, and the connection point between the seventh switch tube S7 and the eighth switch tube S8 is the midpoint of the other bridge arm of the third full-bridge circuit unit 500. The second end of the seventh switch tube S7 is interconnected with the second end of the fifth switch tube S5, and the second end of the eighth switch tube S8 is interconnected with the second end of the sixth switch tube S6. The fifth full-bridge circuit unit 700 may include 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. The first end of the ninth switch tube S9 is interconnected with the first end of the tenth switch tube S10, and the connection point between the ninth switch tube S9 and the tenth switch tube S10 is the midpoint of one bridge arm of the fifth full-bridge circuit unit 700.The first end of the 11th switch tube S11 is interconnected with the first end of the 12th switch tube S12, and the connection point between the 11th switch tube S11 and the 12th switch tube S12 is the midpoint of the other bridge arm of the 5th full-bridge circuit unit 700. The second end of the 11th switch tube S11 is interconnected with the second end of the 9th switch tube S9, and the second end of the 12th switch tube S12 is interconnected with the second end of the 10th switch tube S10.

[0021] Based on one embodiment of the present invention, as shown in FIG. 1, the first half-bridge circuit unit 900 may include a 13th switch tube S13 and a 14th switch tube S14 connected in series. The first end of the 13th switch tube S13 is interconnected with the first end of the 14th switch tube S14, and the connection point between the 13th switch tube S13 and the 14th switch tube S14 is the midpoint of the bridge arm of the first half-bridge circuit unit 900. The second end of the 13th switch tube S13 is interconnected with the second end of the 3rd switch tube S3, and the second end of the 14th switch tube S14 is interconnected with the second end of the 4th switch tube S4. The second half-bridge circuit unit 1000 may include a 15th switch tube S15 and a 16th switch tube S16 connected in series. The first end of the 15th switch tube S15 is interconnected with the first end of the 16th switch tube S16, and the connection point between the 15th switch tube S15 and the 16th switch tube S16 is the midpoint of the bridge arm of the second half-bridge circuit unit 1000. The second end of the 15th switch tube S15 is interconnected with the second end of the 7th switch tube S7, and the second end of the 16th switch tube S16 is interconnected with the second end of the 8th switch tube S8. The third half-bridge circuit unit 1100 may include a 17th switch tube S17 and an 18th switch tube S18 connected in series. The first end of the 17th switch tube S17 is interconnected with the first end of the 18th switch tube S18, and the connection point between the 17th switch tube S17 and the 18th switch tube S18 is the midpoint of the bridge arm of the third half-bridge circuit unit 1100. The second end of the 17th switch tube S17 is interconnected with the second end of the 11th switch tube S11, and the second end of the 18th switch tube S18 is interconnected with the second end of the 12th switch tube S12.

[0022] Based on one embodiment of the present invention, as shown in FIG. 1, the first phase shift inductor unit 1200 may include a first phase shift inductor L1 and a second phase shift inductor L2. One end of the first phase shift inductor L1 is interconnected with the midpoint of one bridge arm of the first full bridge circuit unit 300, and the other end of the first phase shift inductor L1 is interconnected with one end of the first coil 1510. One end of the second phase shift inductor L2 is interconnected with the midpoint of the other bridge arm of the first full bridge circuit unit 300, and the other end of the second phase shift inductor L2 is interconnected with the other end of the first coil 1510. The second phase shift inductor unit 1300 may include a third phase shift inductor L3 and a fourth phase shift inductor L4. One end of the third phase shift inductor L3 is interconnected with the midpoint of one bridge arm of the third full bridge circuit unit 500, and the other end of the third phase shift inductor L3 is interconnected with one end of the third coil 1610. One end of the fourth phase shift inductor L4 is interconnected with the midpoint of the other bridge arm of the third full bridge circuit unit 500, and the other end of the fourth phase shift inductor L4 is interconnected with the other end of the third coil 1610. The third phase shift inductor unit 1400 may include a fifth phase shift inductor L5 and a sixth phase shift inductor L6. One end of the fifth phase shift inductor L5 is interconnected with the midpoint of one bridge arm of the fifth full bridge circuit unit 700, and the other end of the fifth phase shift inductor L5 is interconnected with one end of the fifth coil 1710. One end of the sixth phase shift inductor L6 is interconnected with the midpoint of the other bridge arm of the fifth full bridge circuit unit 700, and the other end of the sixth phase shift inductor L6 is interconnected with the other end of the fifth coil 1710.

[0023] Among them, the inductances of the first phase shift inductor L1 and the second phase shift inductor L2 may be the same, and there may be no coupling relationship or there may be a coupling relationship. When the first phase shift inductor L1 and the second phase shift inductor L2 do not have a coupling relationship, the inductances of the first phase shift inductor L1 and the second phase shift inductor L2 are L pmay be described as such. When the first phase shift inductor L1 and the second phase shift inductor L2 have a coupling relationship, the differential mode inductance is L p.dm may be described as such, and the common mode inductance is L p.cm may be described as such. The coils of the first phase shift inductor L1 and the second phase shift inductor L2 may be wound around two magnetic columns of one magnetic core, may also be wound around two magnetic cores respectively, and may further be wound around the magnetic core of the first transformer 1500 as leakage inductance. Similarly, the third phase shift inductor L3 and the fourth phase shift inductor L4 may be provided in the same way.

[0024] Based on one embodiment of the present invention, as shown in FIG. 1, the second full-bridge circuit unit 400 includes a 19th switch tube S19 and a 20th switch tube S20 connected in series, and a 21st switch tube S21 and a 22nd switch tube S22 connected in series. The first end of the 19th switch tube S19 is interconnected with the first end of the 20th switch tube S20, and the connection point between the 19th switch tube S19 and the 20th switch tube S20 is the midpoint of one bridge arm of the second full-bridge circuit unit 400. The first end of the 21st switch tube S21 is interconnected with the first end of the 22nd switch tube S22, and the connection point between the 21st switch tube S21 and the 22nd switch tube S22 is the midpoint of the other bridge arm of the second full-bridge circuit unit 400. The second end of the 21st switch tube S21 is interconnected with the second end of the 19th switch tube S19, and the second end of the 22nd switch tube S22 is interconnected with the second end of the 20th switch tube S20. The fourth full-bridge circuit unit 600 includes a 23rd switch tube S23 and a 24th switch tube S24 connected in series, and a 25th switch tube S25 and a 26th switch tube S26 connected in series. The first end of the 23rd switch tube S23 is interconnected with the first end of the 24th switch tube S24, and the connection point between the 23rd switch tube S23 and the 24th switch tube S24 is the midpoint of one bridge arm of the fourth full-bridge circuit unit 600. The first end of the 25th switch tube S25 is interconnected with the first end of the 26th switch tube S26, and the connection point between the 25th switch tube S25 and the 26th switch tube S26 is the midpoint of the other bridge arm of the fourth full-bridge circuit unit 600. The second end of the 25th switch tube S25 is interconnected with the second end of the 23rd switch tube S23, and the second end of the 26th switch tube S26 is interconnected with the second end of the 24th switch tube S24. The sixth full-bridge circuit unit 800 includes a 27th switch tube S27 and a 28th switch tube S28 connected in series, and a 29th switch tube S29 and a 30th switch tube S30 connected in series. The first end of the 27th switch tube S27 is interconnected with the first end of the 28th switch tube S28, and the connection point between the 27th switch tube S27 and the 28th switch tube S28 is the midpoint of one bridge arm of the sixth full-bridge circuit unit 800.The first end of the 29th switch tube S29 is interconnected with the first end of the 30th switch tube S30. The connection point between the 29th switch tube S29 and the 30th switch tube S30 is the midpoint of the other bridge arm of the 6th full-bridge circuit unit 800. The second end of the 29th switch tube S29 is interconnected with the second end of the 27th switch tube S27, and the second end of the 30th switch tube S30 is interconnected with the second end of the 28th switch tube S28.

[0025] To enable those skilled in the art to understand the three-phase single-stage isolated bidirectional converter of the embodiments of the present invention more clearly, the operation mode of the three-phase single-stage isolated bidirectional converter will be described in detail below in combination with specific embodiments.

[0026] Taking the first module as an example, the operation modes of the other two modules are the same as that of the first module.

[0027] Specifically, by inputting drive signals to the drive ends of the first to fourth switch tubes S1 to S4, the conduction or disconnection of the first to fourth switch tubes S1 to S4 is controlled, thereby operating the first full-bridge circuit unit 300 according to the following two modes.

[0028] Mode 1: When the first switch tube S1 and the fourth switch tube S4 are in the conduction state, the second switch tube S2 and the third switch tube S3 are in the disconnection state. Mode 2: When the second switch tube S2 and the third switch tube S3 are in the conduction state, the first switch tube S1 and the fourth switch tube S4 are in the disconnection state.

[0029] Among them, the duty ratio of the drive signals of the first to fourth switch tubes S1 to S4 is 50%, and only one of the two switch tubes on the same bridge arm is in the conduction state. Within each switching cycle Ts, Mode 1 and Mode 2 are each executed once, and the duration each occupies is 50%.

[0030] By inputting a drive signal to the drive ends of the 13th switch tube S13 and the 14th switch tube S14, the conduction or disconnection of the 13th switch tube S13 and the 14th switch tube S14 is controlled, thereby controlling the 1st half-bridge circuit unit 900 to operate according to the following method.

[0031] When the three-phase one-stage insulated bidirectional converter is operating in the rectification mode, when the AC terminal voltage V g1 is positive, the 14th switch tube S14 is in the conduction state or the disconnection state, and the 13th switch tube S13 is in the disconnection state. When the AC terminal voltage V g1 is negative, the 13th switch tube S13 is in the conduction state or the disconnection state, and the 14th switch tube S14 is in the disconnection state. When the three-phase one-stage insulated bidirectional converter is operating in the inversion mode, when the AC terminal voltage V g1 is positive, the 13th switch tube S13 is in the conduction state, and the 14th switch tube S14 is in the disconnection state. When the AC terminal voltage V g1 is negative, the 14th switch tube S14 is in the conduction state, and the 13th switch tube S13 is in the disconnection state.

[0032] By inputting a drive signal to the drive ends of the 19th to 22nd switch tubes S19 to S22, the conduction or disconnection of the 19th to 22nd switch tubes S19 to S22 is controlled, thereby controlling the 2nd full-bridge circuit unit 400 to operate according to the following four modes.

[0033] Mode 1: When the 19th switch tube S19 and the 22nd switch tube S22 are in the conduction state, the 20th switch tube S20 and the 21st switch tube S21 are in the disconnection state. Mode 2: When the 20th switch tube S20 and the 21st switch tube S21 are in the conduction state, the 19th switch tube S19 and the 22nd switch tube S22 are in the disconnection state. Mode 3: When the 19th switch tube S19 and the 21st switch tube S21 are in the conduction state, the 20th switch tube S20 and the 22nd switch tube S22 are in the disconnection state. Mode 4: When the 20th switch tube S20 and the 22nd switch tube S22 are in the conduction state, the 19th switch tube S19 and the 21st switch tube S21 are in the disconnection state.

[0034] Among them, the duty ratios of the drive signals of the 19th switch tube S19 and the 22nd switch tube S22 are 50%, and only one of the two switch tubes in the same bridge arm is in the conduction state. Within each switching cycle Ts, each of mode 1, mode 2, mode 3, and mode 4 is executed once, and the execution order and time of each mode depend on the internal phase relationship of the drive signals of each switch tube.

[0035] It should be noted that the internal phase relationship of the drive signals of each switch tube in the second full-bridge circuit unit 400, and the external phase relationship between the drive signal of the second full-bridge circuit unit 400 and the drive signal of the first full-bridge circuit unit 300, can control the power factor of the AC terminal current i g1 and the input / output power at the DC terminal. During the rectification operation, the drive signal of the first full-bridge circuit unit 300 precedes the drive signal of the second full-bridge circuit unit 400, and energy is transmitted from the AC terminal to the DC terminal. During the inverse conversion operation, the drive signal of the first full-bridge circuit unit 300 lags behind the drive signal of the second full-bridge circuit unit 400, and energy is transmitted from the DC terminal to the AC terminal.

[0036] To sum up, the three-phase single-stage isolated bidirectional converter of the present invention includes only single-stage power conversion. Therefore, the loss of the converter is small and the efficiency is high. Moreover, the three-phase single-stage isolated bidirectional converter of the present invention only includes a high-frequency filter capacitor with a small capacitance value for removing the current ripple of the switching frequency, and does not include a bus capacitor with a large capacitance value as an energy buffer unit. Therefore, an aluminum electrolytic capacitor is not required. For this reason, the converter has a small volume and a long lifespan. At the same time, the three-phase single-stage isolated bidirectional converter of the present invention does not require a boost inductor, has very low electromagnetic interference to the power grid, and does not cause further semiconductor switch tube losses or core losses of the phase shift inductor. The topology does not have the characteristics of a boost inductor. Therefore, the volume and magnetic component consumption of the converter are reduced, and the cost of the converter is lowered.

[0037] Summarizing the above, the three-phase single-stage insulated bidirectional converter according to the present invention includes a three-phase AC voltage port, a DC voltage port, first to sixth full-bridge circuit units, first to third half-bridge circuit units, first to third phase-shift inductor units, first to third transformers, first to third filter capacitors, and a controller. Among them, the three-phase AC voltage port includes first to sixth ports. The DC voltage port includes a seventh port and an eighth port. The first transformer includes a first coil and a second coil. The first coil is provided with a first center tap, and the first center tap is interconnected with the first port. Both ends of the first coil are interconnected with the midpoints of two bridge arms of the first full-bridge circuit unit via the first phase-shift inductor unit respectively. Both ends of the second coil are interconnected with the midpoints of two bridge arms of the second full-bridge circuit unit respectively. The second transformer includes a third coil and a fourth coil. The third coil is provided with a second center tap, and the second center tap is interconnected with the third port. Both ends of the third coil are interconnected with the midpoints of two bridge arms of the third full-bridge circuit unit via the second phase-shift inductor unit respectively. Both ends of the fourth coil are interconnected with the midpoints of two bridge arms of the fourth full-bridge circuit unit respectively. The third transformer includes a fifth coil and a sixth coil. The fifth coil is provided with a third center tap, and the third center tap is interconnected with the fifth port. Both ends of the fifth coil are interconnected with the midpoints of two bridge arms of the fifth full-bridge circuit unit via the third phase-shift inductor unit respectively. Both ends of the sixth coil are interconnected with the midpoints of two bridge arms of the sixth full-bridge circuit unit respectively. Both ends of the first full-bridge circuit unit are interconnected with both ends of the first half-bridge circuit unit respectively. Both ends of the third full-bridge circuit unit are interconnected with both ends of the second half-bridge circuit unit respectively. Both ends of the fifth full-bridge circuit unit are interconnected with both ends of the third half-bridge circuit unit respectively.Both ends of the first half-bridge circuit unit are further interconnected with both ends of the first filter capacitor. The midpoint of the bridge arm of the first half-bridge circuit unit is interconnected with the second port. Both ends of the second half-bridge circuit unit are further interconnected with both ends of the second filter capacitor. The midpoint of the bridge arm of the second half-bridge circuit unit is interconnected with the fourth port. Both ends of the third half-bridge circuit unit are further interconnected with both ends of the third filter capacitor. The midpoint of the bridge arm of the third half-bridge circuit unit is interconnected with the sixth port. Both ends of the second full-bridge circuit unit are interconnected with the seventh port and the eighth port respectively. Both ends of the fourth full-bridge circuit unit are interconnected with the seventh port and the eighth port respectively. Both ends of the sixth full-bridge circuit unit are interconnected with the seventh port and the eighth port respectively. Thereby, it includes only one-stage power conversion, and can greatly improve the operation efficiency and accuracy of the converter and enhance the reliability of the system.

[0038] Corresponding to the above embodiment, the present invention further provides a control method for a three-phase one-stage isolated bidirectional converter.

[0039] Specifically, the control method for a three-phase one-stage isolated bidirectional converter according to an embodiment of the present invention includes the steps of collecting the DC current of the DC voltage port and the three-phase AC voltage and three-phase AC current of the three-phase AC voltage port when receiving a rectification or inverse conversion control command, adopting a double closed-loop control method, and generating a drive signal with a duty ratio of 50% based on the three-phase AC voltage, the three-phase AC voltage, and the three-phase AC current, and sending the drive signal to the drive ends of the first to thirteenth switch tubes to control the operation of the three-phase one-stage isolated bidirectional converter in the rectification mode or the inverse conversion mode.

[0040] Based on one embodiment of the present invention, when the three-phase one-stage insulated bidirectional converter operates in the rectification mode, control is performed such that the drive signal corresponding to the first full-bridge circuit unit precedes the drive signal corresponding to the second full-bridge circuit unit, the drive signal corresponding to the third full-bridge circuit unit precedes the drive signal corresponding to the fourth full-bridge circuit unit, and the drive signal corresponding to the fifth full-bridge circuit unit precedes the drive signal corresponding to the sixth full-bridge circuit unit. Among them, the adoption of the double closed-loop control method calculates the phase angle by which the drive signal corresponding to the first full-bridge circuit unit precedes the drive signal corresponding to the second full-bridge circuit unit, the phase angle by which the drive signal corresponding to the third full-bridge circuit unit precedes the drive signal corresponding to the fourth full-bridge circuit unit, and the phase angle by which the drive signal corresponding to the fifth full-bridge circuit unit precedes the drive signal corresponding to the sixth full-bridge circuit unit, respectively.

[0041] Based on one embodiment of the present invention, when the three-phase one-stage insulated bidirectional converter operates in the inversion mode, control is performed such that the drive signal corresponding to the first full-bridge circuit unit lags behind the drive signal corresponding to the second full-bridge circuit unit, the drive signal corresponding to the third full-bridge circuit unit lags behind the drive signal corresponding to the fourth full-bridge circuit unit, and the drive signal corresponding to the fifth full-bridge circuit unit lags behind the drive signal corresponding to the sixth full-bridge circuit unit. Among them, the adoption of the double closed-loop control method calculates the phase angle by which the drive signal corresponding to the first full-bridge circuit unit lags behind the drive signal corresponding to the second full-bridge circuit unit, the phase angle by which the drive signal corresponding to the third full-bridge circuit unit lags behind the drive signal corresponding to the fourth full-bridge circuit unit, and the phase angle by which the drive signal corresponding to the fifth full-bridge circuit unit lags behind the drive signal corresponding to the sixth full-bridge circuit unit, respectively.

[0042] Specifically, when receiving a rectification control command or an inverse conversion control command, the outer loop controller in the double closed-loop control system collects the DC current idc of the DC voltage port 200 (collected by a current sensor). At this time, the outer loop controller generates three-phase current reference values i * g1 、i * g2 、i * g3 through internal control, and transmits the three-phase current reference values i * g1 、i * g2 、i * g3 to the inner loop controller in the double closed-loop control system. Among them, the outer loop controller generates the three-phase current reference values i * g1 、i * g2 、i * g3 through a PI controller and a saturation regulator unit. The inner loop controller collects the three-phase AC current of the three-phase AC voltage port 100 by a current sensor and collects the three-phase AC voltage of the three-phase AC voltage port 100 by a voltage sensor. At this time, the inner loop controller generates a drive signal with a duty ratio of 50% and a phase-shifted phase relationship with each other and transmits it to the main circuit driver for driving, thereby controlling the current i g1 of the three-phase AC voltage port 100 and the current i dc of the DC voltage port 200. For the specific control method of the first to thirtieth switch tubes S1 to S30 by the drive signal with a duty ratio of 50% and a phase-shifted phase relationship with each other, reference can be made to the above embodiment, and in order to avoid redundancy, it will not be repeated here.

[0043] It should be noted that when the three-phase one-stage insulated bidirectional converter operates in the rectification mode, the double closed-loop control system generates the external phase shift angle φ0 (advance phase angle) of each module (the first to the third modules), and controls the drive signal corresponding to the first full-bridge circuit unit to lead the drive signal corresponding to the second full-bridge circuit unit based on the external phase shift angle φ0, controls the drive signal corresponding to the third full-bridge circuit unit to lead the drive signal corresponding to the fourth full-bridge circuit unit, and controls the drive signal corresponding to the fifth full-bridge circuit unit to lead the drive signal corresponding to the sixth full-bridge circuit unit. When the three-phase one-stage insulated bidirectional converter operates in the inversion mode, the double closed-loop control system generates the external phase shift angle φ о (delay phase angle) of each module (the first to the third modules), and controls the drive signal corresponding to the first full-bridge circuit unit to lag behind the drive signal corresponding to the second full-bridge circuit unit based on the external phase shift angle φ о , controls the drive signal corresponding to the third full-bridge circuit unit to lag behind the drive signal corresponding to the fourth full-bridge circuit unit, and controls the drive signal corresponding to the fifth full-bridge circuit unit to lag behind the drive signal corresponding to the sixth full-bridge circuit unit. Also, the double closed-loop control system further generates the internal phase shift angle φ i of each module (the first to the third modules), outputs it to the PWM generator and sends out the PWM waveform, thereby controlling the current i g1 waveform of the three-phase AC voltage port 100.

[0044] Among them, the table lookup method can be adopted to obtain the internal phase shift angle φ i based on the table lookup curve. The table lookup curve is based on the real-time grid voltage V g1 , V g2 , V g3 and the battery voltage U b , and is based on the real-time power combined with them, the theoretical calculation formula of the minimum current stress, or the internal phase shift angle φ i corresponding to the optimal loss operating point measured in the experiment.It is obtained by

[0045] As a point to be explained, the external phase shift angle φ о is the phase difference between the positive half-cycle square wave voltage generated by the switching operation of the full-bridge arm at the AC terminal and the positive half-cycle square wave voltage generated by the switching operation of the full-bridge arm at the DC terminal, and this phase difference is determined by the phase relationship between the drive signals of the full-bridge arm at the AC terminal and the full-bridge arm at the DC terminal. The internal phase shift angle φ i is the phase width of the positive half-cycle square wave voltage generated by the switching operation of the full-bridge arm at the DC terminal, and this width is determined by the phase relationship between the drive signals of the two half-bridge arms of the full-bridge arm at the DC terminal.

[0046] Thus, the present invention solves the closed-loop control problem of the three-phase one-stage insulated AC / DC bidirectional converter, can realize two closed-loop controllers of the three-phase circuit with one control chip, and by sharing the bridge arm drive signals of the three-phase primary side full-bridge, the total number of PWM signals is reduced, which is beneficial for controlling the entire circuit with a single chip. Also, by means of the internal phase shift look-up table, optimization of efficiency at different DC voltages and different power levels can be realized, which is suitable for application in actual products.

[0047] Based on the control method of the three-phase one-stage insulated bidirectional converter of the present invention, when receiving a rectification or inverse conversion control command, collect the DC current of the DC voltage port, collect the three-phase AC voltage and three-phase AC current of the three-phase AC voltage port, adopt a double closed-loop control method, generate a drive signal with a duty ratio of 50% based on the DC current, the three-phase AC voltage, and the three-phase AC current, and send the drive signal to the drive ends of the first to thirtieth switch tubes, thereby controlling the operation of the three-phase one-stage insulated bidirectional converter in the rectification mode or the inverse conversion mode. Thus, it includes only one-stage power conversion, and adopts a double closed-loop control method to generate and control a drive signal with a duty ratio of 50%, thereby greatly improving the operation efficiency and accuracy of the converter and enhancing the reliability of the system.

[0048] In the description of the present invention, the terms "first" and "second" are only used for illustrative purposes and should not be understood as indicating or implying relative importance or the quantity of the indicated technical features. Thus, features with the limitations of "first" and "second" may explicitly or implicitly include one or more of such features. The meaning of "a plurality of" means two or more unless specifically limited otherwise.

[0049] In the present invention, unless otherwise explicitly defined and limited, terms such as "attach", "interconnect", "connect", "fix", etc. should be understood in a broad sense. For example, it may be a fixed connection, a removable connection, or may form an integral body. It may be a mechanical connection or an electrical connection. It may be a direct connection or an indirect connection through an intermediate medium, or may be a communication inside two members or an interaction relationship between two members. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific situation.

[0050] In the present invention, unless otherwise explicitly defined and limited, for the first feature to be "above" or "below" the second feature, it may mean that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Also, for the first feature to be "above", "upward", or "higher" than the second feature, it may mean that the first feature is directly above or obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. For the first feature to be "below", "downward", or "lower" than the second feature, it may mean that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is lower than that of the second feature.

[0051] References in this specification to descriptions such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials, or combinations of characteristics described in the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the general expressions of the above terms do not necessarily refer to the same embodiment or example. Also, 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, when not conflicting with each other, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples.

[0052] A flowchart, or any process or method described herein in another manner, may be understood to represent one or more executable instruction code modules, segments, or portions used to implement specific logical functions or process steps. Also, the scope of the preferred embodiments of the present invention may include additional implementations, among which functions may be executed in an order that includes substantially simultaneous or reverse orders that do not follow the order shown or described based on the related functions, which should be understood by those skilled in the art.

[0053] Logic and / or steps represented in a flowchart or otherwise described herein may be regarded as an ordered listing of executable instructions for implementing logical functions, and may be specifically implemented in any computer-readable medium to be used in an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or another system that retrieves and executes instructions from an instruction execution system, apparatus, or device), or in a combination of these instruction execution systems, apparatuses, or devices. As used herein, a "computer-readable medium" may be any device capable of storing, communicating, propagating, or transporting a program for use in or in connection with an instruction execution system, apparatus, or device, or a combination of these instruction execution systems, apparatuses, or devices. Specific examples of a computer-readable medium (not an exhaustive list) include one or more wired electrical connections (electronic devices), portable computer magnetic disks (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), optical fiber devices, and portable optical disk read-only memory (CDROM). Also, a computer-readable medium may be printable paper or other suitable medium, for example, by optically scanning the paper or other medium and then editing, interpreting, or otherwise processing as appropriate to electronically obtain the program and then store it in a computer memory.

[0054] It should be understood that each part of the present invention can be realized by hardware, software, firmware, or a combination thereof. In the above-described embodiments, a plurality of steps or methods may be realized using software or firmware stored in a memory and executed by an appropriate instruction execution system. For example, when realized using hardware, it may also be realized by any one of the following technologies known in the art, or a combination thereof, in another embodiment: discrete logic circuits equipped with logic gate circuits for realizing logical functions for data signals, application-specific integrated circuits equipped with combinations of appropriate logic gate circuits, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0055] A person skilled in the art can understand that the realization of all or part of the steps involved in the method of the above-described embodiments can be completed by instructing the relevant hardware by a program, and the program may be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0056] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing module, each unit may physically exist independently, or two or more units may be integrated into one module. The above-described integrated module may be realized in the form of hardware or in the form of a software functional module. When the above-described integrated module is realized in the form of a software functional module and sold or used as an independent product, it may be stored in a computer-readable storage medium.

[0057] The above-described storage medium may be a read-only memory, a magnetic disk, an optical disk, or the like. As described above, the embodiments of the present invention have been shown and described. However, it can be understood that the above-described embodiments are examples and should not be construed as limitations on the present invention. Those skilled in the art can make modifications, changes, substitutions, and variations to the above-described embodiments within the scope of the present invention.

Claims

1. A three-phase AC voltage port, a DC voltage port, first to sixth full-bridge circuit units, first to third half-bridge circuit units, first to third phase-shift inductor units, first to third transformers, first to third filter capacitors are included, the three-phase AC voltage port includes first to sixth ports, the DC voltage port includes a seventh port and an eighth port, the first transformer includes a first coil and a second coil, a first center tap is provided on the first coil, the first center tap is interconnected with the first port, both ends of the first coil are respectively interconnected with the midpoints of two bridge arms of the first full-bridge circuit unit via the first phase-shift inductor unit, and both ends of the second coil are respectively interconnected with the midpoints of two bridge arms of the second full-bridge circuit unit, the second transformer includes a third coil and a fourth coil, a second center tap is provided on the third coil, the second center tap is interconnected with the third port, both ends of the third coil are respectively interconnected with the midpoints of two bridge arms of the third full-bridge circuit unit via the second phase-shift inductor unit, and both ends of the fourth coil are respectively interconnected with the midpoints of two bridge arms of the fourth full-bridge circuit unit, the third transformer includes a fifth coil and a sixth coil, a third center tap is provided on the fifth coil, the third center tap is interconnected with the fifth port, both ends of the fifth coil are respectively interconnected with the midpoints of two bridge arms of the fifth full-bridge circuit unit via the third phase-shift inductor unit, and both ends of the sixth coil are respectively interconnected with the midpoints of two bridge arms of the sixth full-bridge circuit unit, both ends of the first full-bridge circuit unit are respectively interconnected with both ends of the first half-bridge circuit unit, both ends of the third full-bridge circuit unit are respectively interconnected with both ends of the second half-bridge circuit unit, and both ends of the fifth full-bridge circuit unit are respectively interconnected with both ends of the third half-bridge circuit unit, Both ends of the first half-bridge circuit unit are further interconnected with both ends of the first filter capacitor. The midpoint of the bridge arm of the first half-bridge circuit unit is interconnected with the second port. Both ends of the second half-bridge circuit unit are further interconnected with both ends of the second filter capacitor. The midpoint of the bridge arm of the second half-bridge circuit unit is interconnected with the fourth port. Both ends of the third half-bridge circuit unit are further interconnected with both ends of the third filter capacitor. The midpoint of the bridge arm of the third half-bridge circuit unit is interconnected with the sixth port. Both ends of the second full-bridge circuit unit are respectively interconnected with the seventh port and the eighth port. Both ends of the fourth full-bridge circuit unit are respectively interconnected with the seventh port and the eighth port. Both ends of the sixth full-bridge circuit unit are respectively interconnected with the seventh port and the eighth port. Characterized in that Three-phase one-stage insulated bidirectional converter.

2. The first full-bridge circuit unit 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. The first end of the first switch tube is interconnected with the first end of the second switch tube. The connection point between the first switch tube and the second switch tube is the midpoint of one bridge arm of the first full-bridge circuit unit. The first end of the third switch tube is interconnected with the first end of the fourth switch tube. The connection point between the third switch tube and the fourth switch tube is the midpoint of the other bridge arm of the first full-bridge circuit unit. The second end of the third switch tube is interconnected with the second end of the first switch tube. The second end of the fourth switch tube is interconnected with the second end of the second switch tube. The third full-bridge circuit unit 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. The first end of the fifth switch tube is interconnected with the first end of the sixth switch tube. The connection point between the fifth switch tube and the sixth switch tube is the midpoint of one bridge arm of the third full-bridge circuit unit. ​ ​ The first end of the seventh switch tube is interconnected with the first end of the eighth switch tube, and the connection point between the seventh switch tube and the eighth switch tube is the midpoint of the other bridge arm of the third full-bridge circuit unit. The second end of the seventh switch tube is interconnected with the second end of the fifth switch tube, and the second end of the eighth switch tube is interconnected with the second end of the sixth switch tube. The fifth full-bridge circuit 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. The first end of the ninth switch tube is interconnected with the first end of the tenth switch tube, and the connection point between the ninth switch tube and the tenth switch tube is the midpoint of one bridge arm of the fifth full-bridge circuit unit. The first end of the eleventh switch tube is interconnected with the first end of the twelfth switch tube, and the connection point between the eleventh switch tube and the twelfth switch tube is the midpoint of the other bridge arm of the fifth full-bridge circuit unit. The second end of the eleventh switch tube is interconnected with the second end of the ninth switch tube, and the second end of the twelfth switch tube is interconnected with the second end of the tenth switch tube. It is characterized in that the three-phase one-stage insulated bidirectional converter according to claim 1.

3. The first half-bridge circuit unit includes a thirteenth switch tube and a fourteenth switch tube connected in series. The first end of the thirteenth switch tube is interconnected with the first end of the fourteenth switch tube, and 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 unit. The second end of the thirteenth switch tube is interconnected with the second end of the third switch tube, and the second end of the fourteenth switch tube is interconnected with the second end of the fourth switch tube. The second half-bridge circuit unit includes a fifteenth switch tube and a sixteenth switch tube connected in series. The first end of the fifteenth switch tube is interconnected with the first end of the sixteenth switch tube, and 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 unit. The second end of the fifteenth switch tube is interconnected with the second end of the seventh switch tube, and the second end of the sixteenth switch tube is interconnected with the second end of the eighth switch tube. The third half-bridge circuit unit The 17th switch tube and the 18th switch tube connected in series are included, the first end of the 17th switch tube is interconnected with the first end of the 18th switch tube, the connection point between the 17th switch tube and the 18th switch tube is the midpoint of the bridge arm of the third half-bridge circuit unit, the second end of the 17th switch tube is interconnected with the second end of the 11th switch tube, and the second end of the 18th switch tube is interconnected with the second end of the 12th switch tube characterized in that the three-phase one-stage insulated bidirectional converter according to claim 2

4. The first phase shift inductor unit includes a first phase shift inductor and a second phase shift inductor and is included, one end of the first phase shift inductor is interconnected with the midpoint of one bridge arm of the first full-bridge circuit unit, and the other end of the first phase shift inductor is interconnected with one end of the first coil, one end of the second phase shift inductor is interconnected with the midpoint of the other bridge arm of the first full-bridge circuit unit, and the other end of the second phase shift inductor is interconnected with the other end of the first coil, The second phase shift inductor unit includes a third phase shift inductor and a fourth phase shift inductor and is included, one end of the third phase shift inductor is interconnected with the midpoint of one bridge arm of the third full-bridge circuit unit, and the other end of the third phase shift inductor is interconnected with one end of the third coil, one end of the fourth phase shift inductor is interconnected with the midpoint of the other bridge arm of the third full-bridge circuit unit, and the other end of the fourth phase shift inductor is interconnected with the other end of the third coil, The third phase shift inductor unit includes a fifth phase shift inductor and a sixth phase shift inductor and is included, one end of the fifth phase shift inductor is interconnected with the midpoint of one bridge arm of the fifth full-bridge circuit unit, and the other end of the fifth phase shift inductor is interconnected with one end of the fifth coil, one end of the sixth phase shift inductor is interconnected with the midpoint of the other bridge arm of the fifth full-bridge circuit unit, and the other end of the sixth phase shift inductor is interconnected with the other end of the fifth coil characterized in that the three-phase one-stage insulated bidirectional converter according to claim 3

5. The second full-bridge circuit unit The 19th switch tube and the 20th switch tube connected in series, The 21st switch tube and the 22nd switch tube connected in series are included, The first end of the 19th switch tube is interconnected with the first end of the 20th switch tube, and the connection point between the 19th switch tube and the 20th switch tube is the midpoint of one bridge arm of the second full-bridge circuit unit, The first end of the 21st switch tube is interconnected with the first end of the 22nd switch tube, and the connection point between the 21st switch tube and the 22nd switch tube is the midpoint of the other bridge arm of the second full-bridge circuit unit. The second end of the 21st switch tube is interconnected with the second end of the 19th switch tube, and the second end of the 22nd switch tube is interconnected with the second end of the 20th switch tube, The fourth full-bridge circuit unit includes the 23rd switch tube and the 24th switch tube connected in series, the 25th switch tube and the 26th switch tube connected in series are included, The first end of the 23rd switch tube is interconnected with the first end of the 24th switch tube, and the connection point between the 23rd switch tube and the 24th switch tube is the midpoint of one bridge arm of the fourth full-bridge circuit unit, The first end of the 25th switch tube is interconnected with the first end of the 26th switch tube, and the connection point between the 25th switch tube and the 26th switch tube is the midpoint of the other bridge arm of the fourth full-bridge circuit unit. The second end of the 25th switch tube is interconnected with the second end of the 23rd switch tube, and the second end of the 26th switch tube is interconnected with the second end of the 24th switch tube, The sixth full-bridge circuit unit includes the 27th switch tube and the 28th switch tube connected in series, the 29th switch tube and the 30th switch tube connected in series are included, The first end of the 27th switch tube is interconnected with the first end of the 28th switch tube, and the connection point between the 27th switch tube and the 28th switch tube is the midpoint of one bridge arm of the sixth full-bridge circuit unit, The first end of the 29th switch tube is interconnected with the first end of the 30th switch tube, and the connection point between the 29th switch tube and the 30th switch tube is the midpoint of the other bridge arm of the 6th full-bridge circuit unit. The second end of the 29th switch tube is interconnected with the second end of the 27th switch tube, and the second end of the 30th switch tube is interconnected with the second end of the 28th switch tube. Characterized in that The three-phase single-stage insulated bidirectional converter according to claim 4.

6. A control method for the three-phase single-stage insulated bidirectional converter according to claim 5, comprising: When receiving a rectification control command or an inversion control command, collecting the DC current of the DC voltage port, and collecting the three-phase AC voltage and three-phase AC current of the three-phase AC voltage port. Adopting a double closed-loop control method, generating a drive signal with a duty ratio of 50% based on the DC current, the three-phase AC voltage, and the three-phase AC current, and sending the drive signal to the drive ends of the first to 13th switch tubes, so as to control the three-phase single-stage insulated bidirectional converter to operate in a rectification mode or an inversion mode. Including the step of Characterized in that Control method.

7. When the three-phase single-stage insulated bidirectional converter operates in a rectification mode, Controlling so that the drive signal corresponding to the first full-bridge circuit unit precedes the drive signal corresponding to the second full-bridge circuit unit. Controlling so that the drive signal corresponding to the third full-bridge circuit unit precedes the drive signal corresponding to the fourth full-bridge circuit unit. Controlling so that the drive signal corresponding to the fifth full-bridge circuit unit precedes the drive signal corresponding to the sixth full-bridge circuit unit. Adopting a double closed-loop control method. The phase angle by which the drive signal corresponding to the first full-bridge circuit unit precedes the drive signal corresponding to the second full-bridge circuit unit. The phase angle by which the drive signal corresponding to the third full-bridge circuit unit precedes the drive signal corresponding to the fourth full-bridge circuit unit. The phase angle by which the drive signal corresponding to the fifth full-bridge circuit unit precedes the drive signal corresponding to the sixth full-bridge circuit unit. Are respectively calculated. Characterized in that The control method for the single-stage insulated bidirectional converter according to claim 6.

8. When the three-phase single-stage insulated bidirectional converter operates in an inversion mode, Control such that the drive signal corresponding to the first full-bridge circuit unit lags behind the drive signal corresponding to the second full-bridge circuit unit, Control such that the drive signal corresponding to the third full-bridge circuit unit lags behind the drive signal corresponding to the fourth full-bridge circuit unit, Control such that the drive signal corresponding to the fifth full-bridge circuit unit lags behind the drive signal corresponding to the sixth full-bridge circuit unit, Adopt a double closed-loop control method, The phase angle by which the drive signal corresponding to the first full-bridge circuit unit lags behind the drive signal corresponding to the second full-bridge circuit unit, The phase angle by which the drive signal corresponding to the third full-bridge circuit unit lags behind the drive signal corresponding to the fourth full-bridge circuit unit, The phase angle by which the drive signal corresponding to the fifth full-bridge circuit unit lags behind the drive signal corresponding to the sixth full-bridge circuit unit are respectively calculated characterized in that The control method of the single-stage isolated bidirectional converter according to claim 7.

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