Wide-range output isolation type bidirectional single-stage converter and control method thereof

Abstract

The invention provides a wide-range output isolation type bidirectional single-stage converter and a control method thereof. The converter comprises an alternating current side voltage port, a direct current voltage port, a first full-bridge circuit unit, a half-bridge circuit unit, a second full-bridge circuit unit, a third full-bridge circuit unit, a coupling circuit unit, a transformer, a switching circuit unit, a filter circuit unit and a bus capacitor, the second winding and the third winding are arranged on the other side of the transformer, the two ends of the first winding are connected with the midpoints of the two bridge arms of the first full-bridge circuit unit through the coupling circuit unit respectively, and the two ends of the second winding are connected with the midpoints of the two bridge arms of the second full-bridge circuit unit. Two ends of the third winding are respectively connected with midpoints of two bridge arms of the third full-bridge circuit unit; the two ends of the second full-bridge circuit unit and the two ends of the third full-bridge circuit unit are connected with one end of the switching circuit unit. And high-low voltage wide-range output can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics, and in particular to a wide-range output isolation type bidirectional single-stage converter and a control method for the wide-range output isolation type bidirectional single-stage converter. Background Art

[0002] In the related art, most of the 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: the full-bridge architecture is adopted, the output voltage is limited, and the high-voltage three-level topology has a duty cycle loss, resulting in the low-voltage output cannot be full power, and the control is complex and the stability is poor. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a wide-range output isolated bidirectional single-stage converter and a control method thereof, which uses a switching circuit unit to switch the working mode between a high-voltage mode and a low-voltage mode, and can use fewer switching tubes to achieve a high and low voltage wide range output. In addition, the present invention only includes one-stage power conversion, and the number of switches required is relatively small. Therefore, the control is simple and the stability is high.

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

[0005] A wide-range output isolated bidirectional single-stage converter, comprising: an AC side voltage port, a DC voltage port, a first full-bridge circuit unit, a half-bridge circuit unit, a second full-bridge circuit unit, a third full-bridge circuit unit, a coupling circuit unit, a transformer, a switching circuit unit, a filter circuit unit and a bus capacitor, wherein the AC side voltage port comprises a first port and a second port; the DC side voltage port comprises a third port and a fourth port; one end of the filter circuit unit is connected to the first port; the transformer comprises a first winding, a second winding and a third winding, the first winding is arranged on one side of the transformer, the second winding and the third winding are arranged on the other side of the transformer, the first winding is provided with a center tap, and the center tap is connected to the other side of the filter circuit unit. One end is connected, the two ends of the first winding are respectively connected to the two bridge arm midpoints of the first full-bridge circuit unit through the coupling circuit unit, the two ends of the second winding are respectively connected to the two bridge arm midpoints of the second full-bridge circuit unit, and the two ends of the third winding are respectively connected to the two bridge arm midpoints of the third full-bridge circuit unit; the two ends of the first full-bridge circuit unit are respectively connected to the two ends of the half-bridge circuit unit; the two ends of the half-bridge circuit unit are also connected to the two ends of the bus capacitor, and the bridge arm midpoint of the half-bridge circuit unit is connected to the second port; the two ends of the second full-bridge circuit unit and the third full-bridge circuit unit are both connected to one end of the switching circuit unit; the other end of the switching circuit unit is respectively connected to the third port and the fourth port.

[0006] In one embodiment of the present invention, the first full-bridge circuit unit includes: a first switch tube and a second switch tube connected in series, 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 unit; a third switch tube and a fourth switch tube connected in series, the second end of the third switch tube is connected to the first end of the fourth switch tube, 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 unit, 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.

[0007] In one embodiment of the present invention, the half-bridge circuit unit includes: a fifth switch tube and a sixth switch tube connected in series, the second end of the fifth switch tube is connected to 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 the bridge arm of the half-bridge circuit unit, the first end of the fifth switch tube is connected to the first end of the third switch tube, and the second end of the sixth switch tube is connected to the second end of the fourth switch tube.

[0008] In one embodiment of the present invention, the coupling circuit unit includes: a first coupling inductor, one end of which is connected to a midpoint of one bridge arm of the first full-bridge circuit unit, and the other end of which is connected to one end of the first winding; and a second coupling inductor, one end of which is connected to a midpoint of another bridge arm of the first full-bridge circuit unit, and the other end of which is connected to the other end of the first winding.

[0009] In one embodiment of the present invention, the second full-bridge circuit unit includes: a seventh switch tube and an eighth switch tube connected in series, 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 a midpoint of a bridge arm of the second full-bridge circuit unit; a ninth switch tube and a tenth switch tube connected in series, 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 another midpoint of the bridge arm of the second full-bridge circuit unit.

[0010] In one embodiment of the present invention, the third full-bridge circuit unit includes: an eleventh switch tube and a twelfth switch tube connected in series, 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 a midpoint of a bridge arm of the third full-bridge circuit unit; a thirteenth switch tube and a fourteenth switch tube connected in series, the second end of the thirteenth switch tube is connected to the first end of the fourteenth switch tube, and the connection point between the thirteenth switch tube and the fourteenth switch tube is another midpoint of the bridge arm of the third full-bridge circuit unit.

[0011] In one embodiment of the present invention, the switching circuit unit includes: a first switch, one end of the first switch is connected to the second end of the tenth switch tube, and the other end of the first switch tube is connected to the first end of the thirteenth switch tube; a second switch, one end of the second switch is connected to the first end of the ninth switch tube, and the other end of the second switch is connected to the first end of the thirteenth switch tube; a third switch, one end of the third switch is connected to the second end of the tenth switch tube, and the other end of the third switch is connected to the second end of the fourteenth switch tube.

[0012] In one embodiment of the present invention, the filter circuit unit includes: a filter inductor, one end of which is connected to the first port; a first resistor, one end of which is connected to the other end of the filter inductor, and the other end of the first resistor is connected to the center tap.

[0013] A control method for a wide-range output isolated bidirectional single-stage converter, the control method comprising the following steps: after receiving a control instruction, judging a control mode according to the control instruction; if it is judged to be a low-voltage rectification mode or a low-voltage inversion mode according to the control instruction, controlling the first switch to be disconnected, controlling the second switch and the third switch to be turned on, and sending corresponding driving signals with a duty cycle of 50% to the driving ends of the first to fourteenth switch tubes, so as to control only one of the two switch tubes in the same bridge arm of the first full-bridge circuit unit to be in a conducting state, and controlling only one of the two switch tubes in the half-bridge circuit unit to be in a conducting state, and controlling the second to fourth switch tubes to be turned on. Only one of the two switch tubes in the same bridge arm in the full-bridge circuit unit is in the on state, and only one of the two switch tubes in the same bridge arm in the third full-bridge circuit unit is controlled to be in the on state, so that the wide-range output isolated bidirectional single-stage converter operates in the rectification mode or the inverter mode, wherein, when the wide-range output isolated bidirectional single-stage converter operates in the rectification mode, the drive signal corresponding to the first full-bridge circuit unit is ahead of the drive signals corresponding to the second full-bridge circuit unit and the third full-bridge circuit unit; when the wide-range output isolated bidirectional single-stage converter operates in the inverter mode, the drive signal corresponding to the first full-bridge circuit unit is ahead of the drive signals corresponding to the second full-bridge circuit unit and the third full-bridge circuit unit; lagged behind the driving signals corresponding to the second full-bridge circuit unit and the third full-bridge circuit unit; if it is determined as a high-voltage rectification mode or a high-voltage inverter mode according to the control instruction, the first switch is controlled to be turned on, and the second switch and the third switch are controlled to be turned off, and a corresponding driving signal with a duty cycle of 50% is sent to the driving end of the first to fourteenth switch tubes, so as to control only one of the two switch tubes in the same bridge arm of the first full-bridge circuit unit to be in a conducting state, and control only one of the two switch tubes in the half-bridge circuit unit to be in a conducting state, and control only one of the two switch tubes in the same bridge arm of the second full-bridge circuit unit to be in a conducting state, And control only one of the two switch tubes in the same bridge arm of the third full-bridge circuit unit to be in the on state, so that the wide-range output isolated bidirectional single-stage converter operates in the rectification mode or the inverter mode, wherein, when the wide-range output isolated bidirectional single-stage converter operates in the rectification mode, the drive signal corresponding to the first full-bridge circuit unit is ahead of the drive signals corresponding to the second full-bridge circuit unit and the third full-bridge circuit unit; when the wide-range output isolated bidirectional single-stage converter operates in the inverter mode, the drive signal corresponding to the first full-bridge circuit unit lags behind the drive signals corresponding to the second full-bridge circuit unit and the third full-bridge circuit unit.

[0014] Beneficial effects of the present invention:

[0015] The present invention uses a switching circuit unit to switch the working mode between a high voltage mode and a low voltage mode, and can use fewer switching tubes to achieve a wide range of high and low voltage outputs. In addition, the present invention only includes one-stage power conversion and requires a small number of switches. Therefore, the control is simple and the stability is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of a wide-range output isolated bidirectional single-stage converter according to an embodiment of the present invention;

[0017] Figure 2 A switching control timing diagram of a wide-range output isolated bidirectional single-stage converter in a specific embodiment of the present invention when operating in a high-voltage rectification mode and a low-voltage rectification mode;

[0018] Figure 3 It is a schematic diagram of a wide-range output isolated bidirectional single-stage converter according to a specific embodiment of the present invention when operating in the first stage of rectification mode;

[0019] Figure 4 It is a schematic diagram of a wide-range output isolated bidirectional single-stage converter according to a specific embodiment of the present invention when operating in the second stage of the rectification mode;

[0020] Figure 5 It is a schematic diagram of a wide-range output isolated bidirectional single-stage converter according to a specific embodiment of the present invention when operating in the third stage of the rectification mode;

[0021] Figure 6 It is a schematic diagram of a wide-range output isolated bidirectional single-stage converter according to a specific embodiment of the present invention when operating in the fourth stage of the rectification mode;

[0022] Figure 7 It is a schematic diagram of a wide-range output isolated bidirectional single-stage converter according to a specific embodiment of the present invention when operating in the fifth stage of the rectification mode;

[0023] Figure 8 It is a schematic diagram of a wide-range output isolated bidirectional single-stage converter operating in the sixth stage of the rectification mode according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0024] 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.

[0025] Figure 1 4 is a schematic diagram of the structure of a wide-range output isolated bidirectional single-stage converter according to an embodiment of the present invention.

[0026] Specifically, Figure 1 As shown, the wide-range output isolated bidirectional single-stage converter of the embodiment of the present invention may include: an AC side voltage port 100, a DC voltage port 200, a first full-bridge circuit unit 300, a half-bridge circuit unit 400, a second full-bridge circuit unit 500, a third full-bridge circuit unit 600, a coupling circuit unit 700, a transformer 800, a switching circuit unit 900, a filter circuit unit 1000 and a bus capacitor 1100.

[0027] Among them, the AC side voltage port 100 includes a first port A and a second port B; the DC side voltage port 200 includes a third port C and a fourth port D; one end of the filter circuit unit 1000 is connected to the first port A; the transformer 800 includes a first winding 810, a second winding 820 and a third winding 830, the first winding 810 is arranged on one side of the transformer 800, the second winding 820 and the third winding 830 are arranged on the other side of the transformer 800, the first winding 810 is provided with a center tap, the center tap is connected to the other end of the filter circuit unit 1000, and the two ends of the first winding 810 are respectively connected to the midpoints of the two bridge arms of the first full-bridge circuit unit 300 through the coupling circuit unit 700. The two ends of the second winding 820 are respectively connected to the two bridge arm midpoints of the second full-bridge circuit unit 500, and the two ends of the third winding 830 are respectively connected to the two bridge arm midpoints of the third full-bridge circuit unit 600; the two ends of the first full-bridge circuit unit 300 are respectively connected to the two ends of the half-bridge circuit unit 400; the two ends of the half-bridge circuit unit 400 are also connected to the two ends of the bus capacitor 1100, and the bridge arm midpoint of the half-bridge circuit unit 400 is connected to the second port B; both ends of the second full-bridge circuit unit 500 and the third full-bridge circuit unit 600 are connected to one end of the switching circuit unit 900; the other end of the switching circuit unit 900 is respectively connected to the third port C and the fourth port D.

[0028] In one embodiment of the present invention, Figure 1As shown, the first full-bridge circuit unit 300 includes: a first switch tube S1 and a second switch tube S2 connected in series, 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 unit; a third switch tube S3 and a fourth switch tube S4 connected in series, the second end of the third switch tube S3 is connected to the first end of the fourth switch tube S4, the connection point b between the third switch tube S3 and the fourth switch tube S4 is another midpoint of the bridge arm of the first full-bridge circuit unit, the first end of the third switch tube S3 is connected to the first end of the first switch tube S1, and the second end of the fourth switch tube S4 is connected to the second end of the second switch tube S2.

[0029] According to one embodiment of the present invention, Figure 1 As shown, the half-bridge circuit unit 400 includes: a fifth switch tube S5 and a sixth switch tube S6 connected in series, the second end of the fifth switch tube S5 is connected to the first end of the sixth switch tube S6, the connection point c between the fifth switch tube S5 and the sixth switch tube S6 is the midpoint of the bridge arm of the half-bridge circuit unit 400, the first end of the fifth switch tube S5 is connected to the first end of the third switch tube S3, and the second end of the sixth switch tube S6 is connected to the second end of the fourth switch tube S4.

[0030] According to one embodiment of the present invention, Figure 1 As shown, the coupling circuit unit 700 includes: a first coupling inductor L1 and a second coupling inductor L2, one end of the first coupling inductor L1 is connected to a midpoint of a bridge arm of the first full-bridge circuit unit 300, and the other end of the first coupling inductor L1 is connected to one end of the first winding 810; one end of the second coupling inductor L2 is connected to the midpoint of another bridge arm of the first full-bridge circuit unit 300, and the other end of the second coupling inductor L2 is connected to the other end of the first winding 810.

[0031] According to one embodiment of the present invention, Figure 1 As shown, the second full-bridge circuit unit 500 includes: a seventh switch tube S7 and an eighth switch tube S8 connected in series, and a ninth switch tube S9 and a tenth switch tube S10 connected in series, wherein the second end of the seventh switch tube S7 is connected to the first end of the eighth switch tube S8, and the connection point d between the seventh switch tube S7 and the eighth switch tube S8 is a bridge arm midpoint of the wide voltage output unit 500; the second end of the ninth switch tube S9 is connected to the first end of the tenth switch tube S10, and the connection point e between the ninth switch tube S9 and the tenth switch tube S10 is another bridge arm midpoint of the second full-bridge circuit unit 500.

[0032] According to one embodiment of the present invention, Figure 1As shown, the third full-bridge circuit unit 600 may include: an eleventh switch tube S11 and a twelfth switch tube S12 connected in series and a thirteenth switch tube S13 and a fourteenth switch tube S14 connected in series, wherein 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 between the eleventh switch tube S11 and the connection point S12 of the twelfth switch tube is a bridge arm midpoint of the third full-bridge circuit unit 600; 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 another bridge arm midpoint of the third full-bridge circuit unit.

[0033] In one embodiment of the present invention, Figure 1 As shown, the switching circuit unit includes: a first switch K1, a second switch K2 and a third switch K3. Among them, one end of the first switch K1 is connected to the second end of the tenth switch tube S10, and the other end of the first switch tube K1 is connected to the first end of the thirteenth switch tube S13; one end of the second switch K2 is connected to the first end of the ninth switch tube S9, and the other end of the second switch K2 is connected to the first end of the thirteenth switch tube S13; one end of the third switch K3 is connected to the second end of the tenth switch tube S10, and the other end of the third switch K3 is connected to the second end of the fourteenth switch tube S14.

[0034] In one embodiment of the present invention, Figure 1 As shown, the filter circuit unit 1000 includes: a filter inductor L3 and a first resistor R1.

[0035] One end of the filter inductor L3 is connected to the first port A; one end of the first resistor R1 is connected to the other end of the filter inductor L3 , and the other end of the first resistor R1 is connected to the center tap.

[0036] In order to enable those skilled in the art to more clearly understand the wide-range output isolated bidirectional single-stage converter according to the embodiment of the present invention, the working mode of the wide-range output isolated bidirectional single-stage converter is described in detail below in conjunction with specific embodiments.

[0037] 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 full-bridge circuit unit 300 is controlled to operate in the following two modes:

[0038] 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.

[0039] The duty cycle of the driving signal of the first to fourth switch tubes S1-S4 is 50%, and only one of the two switch tubes in the same bridge arm is in the on state. In each switching cycle, mode 1 and mode 2 are executed once, and the duration is 50% each.

[0040] By inputting a driving signal to the driving terminals of the fifth switch tube S5 and the sixth switch tube S6 to control the fifth switch tube S5 and the sixth switch tube S6 to be turned on or off, the half-bridge circuit unit 400 is controlled to operate in the following manner:

[0041] If the wide range output isolated bidirectional single-stage converter works in rectification mode, when the AC terminal voltage V g When the AC terminal voltage V g When the AC terminal voltage V g When the AC terminal voltage V g When it is negative, the sixth switch tube S6 is in the on state, and the fifth switch tube S5 is in the off state.

[0042] It should be noted that the AC side voltage and AC side current of the AC input port can be collected on the AC side, and the DC side voltage and DC side current can be collected on the DC side. When a rectification or inversion instruction is received, a dual closed-loop control strategy can be adopted to generate a high-frequency drive signal and an industrial frequency drive signal according to the AC side current and the DC side current, or the AC side voltage and the DC side voltage, and send a drive signal to each switch tube to realize the rectification mode or the inversion mode.

[0043] According to a specific embodiment of the present invention, taking the rectification mode as an example, Figure 2 This is a switching control timing diagram of a wide-range output isolated bidirectional single-stage converter in high-voltage rectification mode / low-voltage rectification mode within one industrial frequency cycle. The high-voltage rectification mode and the low-voltage rectification mode are used as examples for explanation below. The operation modes in the high-voltage inverter mode and the low-voltage inverter mode can refer to the high-voltage rectification mode and the low-voltage rectification mode.

[0044] Specifically, first, the first switch K1 may be controlled to be turned on, and the second switch K2 and the third switch K3 may be controlled to be turned off.

[0045] Secondly, in the first stage of the high voltage rectification mode operation, i.e., stage 1, as Figure 3 As shown ( Figure 3-8The gray filling of the device in the figure indicates that the device is turned off / disconnected), the first switch tube S1, the fourth switch tube S4, the sixth switch tube S6, the eighth switch tube S8, the ninth switch tube S9, the twelfth switch tube S12 and the thirteenth switch tube S13 are in the on state, the second switch tube S2, the third switch tube S3, the fifth switch tube S5, the seventh switch tube S7, the tenth switch tube S10, the eleventh switch tube S11 and the fourteenth switch tube S14 are in the off state, corresponding to Figure 2 Phase I of

[0046] In the second stage of the high voltage rectification mode operation, i.e., stage 2, as Figure 4 As shown, the first switch tube S1, the fourth switch tube S4, the sixth switch tube S6, the ninth switch tube S8, the tenth switch tube S10, the twelfth switch tube S12 and the fourteenth switch tube S14 are in the on state, and the second switch tube S2, the third switch tube S3, the fifth switch tube S5, the seventh switch tube S7, the ninth switch tube S9, the eleventh switch tube S11 and the thirteenth switch tube S13 are in the off state, corresponding to Figure 2 Phase II.

[0047] In the third stage of the high voltage rectification mode operation, i.e., stage 3, as Figure 5 As shown, the first switch tube S1, the fourth switch tube S4, the sixth switch tube S6, the seventh switch tube S7, the tenth switch tube S10, the eleventh switch tube S11 and the fourteenth switch tube S14 are in the on state, and the second switch tube S2, the third switch tube S3, the fifth switch tube S5, the eighth switch tube S8, the ninth switch tube S9, the twelfth switch tube S12 and the thirteenth switch tube S13 are in the off state, corresponding to Figure 2 Phase III.

[0048] In the fourth stage of the high voltage rectification mode operation, i.e., stage 4, as Figure 6 As shown, the second switch tube S2, the third switch tube S3, the sixth switch tube S6, the seventh switch tube S7, the tenth switch tube S10, the eleventh switch tube S11 and the fourteenth switch tube S14 are in the on state, and the first switch tube S1, the fourth switch tube S4, the fifth switch tube S5, the eighth switch tube S8, the ninth switch tube S9, the twelfth switch tube S12 and the thirteenth switch tube S13 are in the off state, corresponding to Figure 2 Phase IV.

[0049] In the fifth stage of the high voltage rectification mode operation, i.e., stage 5, as Figure 7As shown, the second switch tube S2, the third switch tube S3, the sixth switch tube S6, the seventh switch tube S7, the ninth switch tube S9, the eleventh switch tube S11 and the thirteenth switch tube S13 are in the on state, and the first switch tube S1, the fourth switch tube S4, the fifth switch tube S5, the eighth switch tube S8, the tenth switch tube S10, the twelfth switch tube S12 and the fourteenth switch tube S14 are in the off state, corresponding to Figure 2 Phase V.

[0050] In the sixth stage of the high voltage rectification mode operation, i.e. stage 6, if Figure 8 As shown, the second switch tube S2, the third switch tube S3, the sixth switch tube S6, the eighth switch tube S8, the ninth switch tube S9, the twelfth switch tube S12 and the thirteenth switch tube S13 are in the on state, and the first switch tube S1, the fourth switch tube S4, the fifth switch tube S5, the seventh switch tube S7, the tenth switch tube S10, the eleventh switch tube S11 and the fourteenth switch tube S14 are in the off state, corresponding to Figure 2 Phase VI.

[0051] In summary, in the high-voltage rectification mode, the first switch K1 is controlled to be turned on, and the second switch K2 and the third switch K3 are controlled to be turned off. Therefore, the second full-bridge circuit unit 500 and the third full-bridge circuit unit 600 are used in series, so that high voltage and low current output can be achieved, that is, the output voltage V0=U de +U fg , the output voltage can be doubled compared to the traditional structure.

[0052] Corresponding to the on / off state of each device in the high-voltage rectification mode of the above embodiment, in the low-voltage rectification mode, the first switch K1 can be controlled to be turned off, and the second switch K2 and the third switch K3 can be controlled to be turned on. Then, in each stage of the low-voltage rectification mode working stage, the on / off state of each device is the same as the on / off state of each device in the high-voltage rectification mode, corresponding to Figure 2 It should be noted that, in the low-voltage rectification mode, the first switch K1 is controlled to be disconnected, and the second switch K2 and the third switch K3 are controlled to be turned on, so the second full-bridge circuit unit 500 and the third full-bridge circuit unit 600 are used in parallel, so that low voltage and high current output can be achieved.

[0053] According to an embodiment of the present invention, a wide-range output isolated bidirectional single-stage converter includes: an AC side voltage port, a DC voltage port, a first full-bridge circuit unit, a half-bridge circuit unit, a second full-bridge circuit unit, a third full-bridge circuit unit, a coupling circuit unit, a transformer, a switching circuit unit, a filter circuit unit and a bus capacitor, wherein the AC side voltage port includes a first port and a second port; the DC side voltage port includes a third port and a fourth port; one end of the filter circuit unit is connected to the first port; the transformer includes a first winding, a second winding and a third winding, the first winding is arranged on one side of the transformer, the second winding and the third winding are arranged on the other side of the transformer, the first winding is provided with a center tap, and the center tap The two ends of the first winding are connected to the two bridge arm midpoints of the first full-bridge circuit unit through the coupling circuit unit, the two ends of the second winding are connected to the two bridge arm midpoints of the second full-bridge circuit unit, and the two ends of the third winding are connected to the two bridge arm midpoints of the third full-bridge circuit unit; the two ends of the first full-bridge circuit unit are connected to the two ends of the half-bridge circuit unit; the two ends of the half-bridge circuit unit are also connected to the two ends of the bus capacitor, and the bridge arm midpoint of the half-bridge circuit unit is connected to the second port; the two ends of the second full-bridge circuit unit and the third full-bridge circuit unit are connected to one end of the switching circuit unit; the other end of the switching circuit unit is connected to the third port and the fourth port respectively. Thus, the switching circuit unit is used to switch the working mode between the high-voltage mode (including the high-voltage rectification mode and the high-voltage inverter mode) and the low-voltage mode (including the low-voltage rectification mode and the low-voltage inverter mode), and a relatively small number of switch tubes can be used to achieve a wide range of high and low voltage outputs. In addition, the present invention only includes one-stage power conversion, and the number of switches required is relatively small, so the control is simple and the stability is high.

[0054] Corresponding to the above-mentioned embodiment, the present invention further proposes a control method for a wide-range output isolated bidirectional single-stage converter.

[0055] The control method includes the following steps: after receiving a control instruction, judging a control mode according to the control instruction; if it is judged as a low-voltage rectification mode or a low-voltage inverter mode according to the control instruction, controlling the first switch to be disconnected, and controlling the second switch and the third switch to be turned on, and sending a corresponding driving signal with a duty cycle of 50% to the driving end of the first to fourteenth switch tubes, so as to control only one of the two switch tubes in the same bridge arm of the first full-bridge circuit unit to be in a conducting state, and controlling only one of the two switch tubes in the half-bridge circuit unit to be in a conducting state, and controlling the two switch tubes in the same bridge arm of the second full-bridge circuit unit to be turned on. Only one of the switch tubes is in the on state, and only one of the two switch tubes in the same bridge arm of the third full-bridge circuit unit is controlled to be in the on state, so that the wide-range output isolated bidirectional single-stage converter operates in the rectification mode or the inverter mode, wherein, when the wide-range output isolated bidirectional single-stage converter operates in the rectification mode, the drive signal corresponding to the first full-bridge circuit unit is ahead of the drive signals corresponding to the second full-bridge circuit unit and the third full-bridge circuit unit; when the wide-range output isolated bidirectional single-stage converter operates in the inverter mode, the drive signal corresponding to the first full-bridge circuit unit lags behind the drive signal corresponding to the second full-bridge circuit unit. If the high-voltage rectification mode or the high-voltage inverter mode is determined according to the control instruction, the first switch is controlled to be turned on, and the second switch and the third switch are controlled to be turned off, and a corresponding driving signal with a duty cycle of 50% is sent to the driving end of the first to fourteenth switch tubes to control only one of the two switch tubes in the same bridge arm in the first full-bridge circuit unit to be in the on state, and only one of the two switch tubes in the half-bridge circuit unit is controlled to be in the on state, and only one of the two switch tubes in the second full-bridge circuit unit is controlled to be in the on state, and Only one of the two switch tubes in the same bridge arm of the third full-bridge circuit unit is in the on state, so that the wide-range output isolated bidirectional single-stage converter operates in the rectification mode or the inverter mode, wherein, when the wide-range output isolated bidirectional single-stage converter operates in the rectification mode, the drive signal corresponding to the first full-bridge circuit unit is ahead of the drive signals corresponding to the second full-bridge circuit unit and the third full-bridge circuit unit; when the wide-range output isolated bidirectional single-stage converter operates in the inverter mode, the drive signal corresponding to the first full-bridge circuit unit lags behind the drive signals corresponding to the second full-bridge circuit unit and the third full-bridge circuit unit.

[0056] 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 full-bridge circuit unit 300 is controlled to operate in the following two modes:

[0057] 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.

[0058] The duty cycle of the driving signal of the first to fourth switch tubes S1-S4 is 50%, and only one of the two switch tubes in the same bridge arm is in the on state. In each switching cycle, mode 1 and mode 2 are executed once, and the duration is 50% each.

[0059] By inputting a driving signal to the driving terminals of the fifth switch tube S5 and the sixth switch tube S6 to control the fifth switch tube S5 and the sixth switch tube S6 to be turned on or off, the half-bridge circuit unit 400 is controlled to operate in the following manner:

[0060] If the wide range output isolated bidirectional single-stage converter works in rectification mode, when the AC terminal voltage V g When the AC terminal voltage V g When the AC terminal voltage V g When the AC terminal voltage V g When it is negative, the sixth switch tube S6 is in the on state, and the fifth switch tube S5 is in the off state.

[0061] It should be noted that the AC side voltage and AC side current of the AC input port can be collected on the AC side, and the DC side voltage and DC side current can be collected on the DC side. When a rectification or inversion instruction is received, a dual closed-loop control strategy can be adopted to generate a high-frequency drive signal and an industrial frequency drive signal according to the AC side current and the DC side current, or the AC side voltage and the DC side voltage, and send a drive signal to each switch tube to realize the rectification mode or the inversion mode.

[0062] According to a specific embodiment of the present invention, taking the rectification mode as an example, Figure 2 This is a switching control timing diagram of a wide-range output isolated bidirectional single-stage converter in high-voltage rectification mode / low-voltage rectification mode within one industrial frequency cycle. The high-voltage rectification mode and the low-voltage rectification mode are used as examples for explanation below. The operation modes in the high-voltage inverter mode and the low-voltage inverter mode can refer to the high-voltage rectification mode and the low-voltage rectification mode.

[0063] Specifically, first, the first switch K1 may be controlled to be turned on, and the second switch K2 and the third switch K3 may be controlled to be turned off.

[0064] Secondly, in the first stage of the high voltage rectification mode operation, i.e., stage 1, as Figure 3 As shown (the gray filled part indicates that the device is turned off / disconnected), the first switch tube S1, the fourth switch tube S4, the sixth switch tube S6, the eighth switch tube S8, the ninth switch tube S9, the twelfth switch tube S12 and the thirteenth switch tube S13 are in the on state, and the second switch tube S2, the third switch tube S3, the fifth switch tube S5, the seventh switch tube S7, the tenth switch tube S10, the eleventh switch tube S11 and the fourteenth switch tube S14 are in the off state, corresponding to Figure 2 Phase I of

[0065] In the second stage of the high voltage rectification mode operation, i.e., stage 2, as Figure 4 As shown, the first switch tube S1, the fourth switch tube S4, the sixth switch tube S6, the ninth switch tube S8, the tenth switch tube S10, the twelfth switch tube S12 and the fourteenth switch tube S14 are in the on state, and the second switch tube S2, the third switch tube S3, the fifth switch tube S5, the seventh switch tube S7, the ninth switch tube S9, the eleventh switch tube S11 and the thirteenth switch tube S13 are in the off state, corresponding to Figure 2 Phase II.

[0066] In the third stage of the high voltage rectification mode operation, i.e., stage 3, as Figure 5 As shown, the first switch tube S1, the fourth switch tube S4, the sixth switch tube S6, the seventh switch tube S7, the tenth switch tube S10, the eleventh switch tube S11 and the fourteenth switch tube S14 are in the on state, and the second switch tube S2, the third switch tube S3, the fifth switch tube S5, the eighth switch tube S8, the ninth switch tube S9, the twelfth switch tube S12 and the thirteenth switch tube S13 are in the off state, corresponding to Figure 2 Phase III.

[0067] In the fourth stage of the high voltage rectification mode operation, i.e., stage 4, as Figure 6 As shown, the second switch tube S2, the third switch tube S3, the sixth switch tube S6, the seventh switch tube S7, the tenth switch tube S10, the eleventh switch tube S11 and the fourteenth switch tube S14 are in the on state, and the first switch tube S1, the fourth switch tube S4, the fifth switch tube S5, the eighth switch tube S8, the ninth switch tube S9, the twelfth switch tube S12 and the thirteenth switch tube S13 are in the off state, corresponding to Figure 2 Phase IV.

[0068] In the fifth stage of the high voltage rectification mode operation, i.e., stage 5, as Figure 7As shown, the second switch tube S2, the third switch tube S3, the sixth switch tube S6, the seventh switch tube S7, the ninth switch tube S9, the eleventh switch tube S11 and the thirteenth switch tube S13 are in the on state, and the first switch tube S1, the fourth switch tube S4, the fifth switch tube S5, the eighth switch tube S8, the tenth switch tube S10, the twelfth switch tube S12 and the fourteenth switch tube S14 are in the off state, corresponding to Figure 2 Phase V.

[0069] In the sixth stage of the high voltage rectification mode operation, i.e. stage 6, if Figure 8 As shown, the second switch tube S2, the third switch tube S3, the sixth switch tube S6, the eighth switch tube S8, the ninth switch tube S9, the twelfth switch tube S12 and the thirteenth switch tube S13 are in the on state, and the first switch tube S1, the fourth switch tube S4, the fifth switch tube S5, the seventh switch tube S7, the tenth switch tube S10, the eleventh switch tube S11 and the fourteenth switch tube S14 are in the off state, corresponding to Figure 2 Phase VI.

[0070] In summary, in the high-voltage rectification mode, the first switch K1 is controlled to be turned on, and the second switch K2 and the third switch K3 are controlled to be turned off. Therefore, the second full-bridge circuit unit 500 and the third full-bridge circuit unit 600 are used in series, so that high voltage and low current output can be achieved, that is, the output voltage V0=U de +U fg , the output voltage can be doubled compared to the traditional structure.

[0071] Corresponding to the on / off state of each device in the high-voltage rectification mode of the above embodiment, in the low-voltage rectification mode, the first switch K1 can be controlled to be turned off, and the second switch K2 and the third switch K3 can be controlled to be turned on. Then, in each stage of the low-voltage rectification mode working stage, the on / off state of each device is the same as the on / off state of each device in the high-voltage rectification mode, corresponding to Figure 2 It should be noted that, in the low voltage rectification mode, the first switch K1 is controlled to be disconnected, and the second switch K2 and the third switch K3 are controlled to be turned on. Therefore, the second full-bridge circuit unit 500 and the third full-bridge circuit unit 600 are used in parallel, so that low voltage and high current output can be achieved.

[0072] According to the control method of the wide-range output isolated bidirectional single-stage converter of the embodiment of the present invention, after receiving the control instruction, the control mode is determined according to the control instruction; if it is determined to be a low-voltage rectification mode or a low-voltage inverter mode according to the control instruction, the first switch is controlled to be disconnected, and the second switch and the third switch are controlled to be turned on, and a corresponding driving signal with a duty cycle of 50% is sent to the driving end of the first to fourteenth switch tubes, so as to control only one switch tube of the two switch tubes in the same bridge arm in the first full-bridge circuit unit to be in the on state, and control only one switch tube of the two switch tubes in the half-bridge circuit unit to be in the on state, and control the second full-bridge circuit unit to be in the on state. Only one of the two switch tubes in the same bridge arm of the unit is in the on state, and only one of the two switch tubes in the same bridge arm of the third full-bridge circuit unit is controlled to be in the on state, so that the wide-range output isolated bidirectional single-stage converter operates in the rectification mode or the inverter mode, wherein, when the wide-range output isolated bidirectional single-stage converter operates in the rectification mode, the drive signal corresponding to the first full-bridge circuit unit is ahead of the drive signals corresponding to the second full-bridge circuit unit and the third full-bridge circuit unit; when the wide-range output isolated bidirectional single-stage converter operates in the inverter mode, the drive signal corresponding to the first full-bridge circuit unit lags behind The drive signals corresponding to the second full-bridge circuit unit and the third full-bridge circuit unit; if it is determined to be a high-voltage rectification mode or a high-voltage inverter mode according to the control instruction, the first switch is controlled to be turned on, and the second switch and the third switch are controlled to be turned off, and a corresponding drive signal with a duty cycle of 50% is sent to the driving end of the first to fourteenth switch tubes to control only one of the two switch tubes in the same bridge arm in the first full-bridge circuit unit to be in the on state, and control only one of the two switch tubes in the half-bridge circuit unit to be in the on state, and control only one of the two switch tubes in the same bridge arm in the second full-bridge circuit unit to be in the on state. state, and control only one switch tube of the two switch tubes in the same bridge arm in the third full-bridge circuit unit to be in the on state, so that the wide-range output isolated bidirectional single-stage converter works in the rectification mode or the inverter mode, wherein, when the wide-range output isolated bidirectional single-stage converter works in the rectification mode, the drive signal corresponding to the first full-bridge circuit unit is ahead of the drive signals corresponding to the second full-bridge circuit unit and the third full-bridge circuit unit; when the wide-range output isolated bidirectional single-stage converter works in the inverter mode, the drive signal corresponding to the first full-bridge circuit unit lags behind the drive signals corresponding to the second full-bridge circuit unit and the third full-bridge circuit unit. Thus, the switching circuit unit is used to switch the working mode between the high-voltage mode and the low-voltage mode, and a relatively small number of switch tubes can be used to achieve a high-low voltage wide range output, and the present invention only includes one-stage power conversion, and the number of switches required is relatively small, so the control is simple and the stability is high.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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 isolation type bidirectional single-stage converter, characterized in that: include: AC side voltage port, DC voltage port, first full-bridge circuit unit, half-bridge circuit unit, second full-bridge circuit unit, third full-bridge circuit unit, coupling circuit unit, transformer, switching circuit unit, filter circuit unit and bus capacitor, wherein, The AC side voltage port includes a first port and a second port; The DC side voltage port includes a third port and a fourth port; One end of the filter circuit unit is connected to the first port; The transformer comprises a first winding, a second winding and a third winding, wherein the first winding is arranged on one side of the transformer, the second winding and the third winding are arranged on the other side of the transformer, the first winding is provided with a center tap, the center tap is connected to the other end of the filter circuit unit, the two ends of the first winding are respectively connected to the midpoints of the two bridge arms of the first full-bridge circuit unit through the coupling circuit unit, the two ends of the second winding are respectively connected to the midpoints of the two bridge arms of the second full-bridge circuit unit, and the two ends of the third winding are respectively connected to the midpoints of the two bridge arms of the third full-bridge circuit unit; Two ends of the first full-bridge circuit unit are respectively connected to two ends of the half-bridge circuit unit; The two ends of the half-bridge circuit unit are also connected to the two ends of the bus capacitor, and the midpoint of the bridge arm of the half-bridge circuit unit is connected to the second port; Both ends of the second full-bridge circuit unit and the third full-bridge circuit unit are connected to one end of the switching circuit unit; The other end of the switching circuit unit is connected to the third port and the fourth port respectively.

2. The wide-range output isolated bidirectional single-stage converter according to claim 1, characterized in that: The first full-bridge circuit unit comprises: A first switch tube and a second 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 unit; A third switch tube and a fourth switch tube are connected in series, the second end of the third switch tube is connected to 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 another bridge arm of the first full-bridge circuit unit, 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.

3. The wide-range output isolated bidirectional single-stage converter according to claim 2, characterized in that: The half-bridge circuit unit comprises: A fifth switch tube and a sixth switch tube are connected in series, the second end of the fifth switch tube is connected to 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 the bridge arm of the half-bridge circuit unit, the first end of the fifth switch tube is connected to the first end of the third switch tube, and the second end of the sixth switch tube is connected to the second end of the fourth switch tube.

4. The wide-range output isolated bidirectional single-stage converter according to claim 3, characterized in that: The coupling circuit unit comprises: A first coupled inductor, one end of the first coupled inductor is connected to a midpoint of a bridge arm of the first full-bridge circuit unit, and the other end of the first coupled inductor is connected to one end of the first winding; A second coupled inductor, one end of the second coupled inductor is connected to a midpoint of another bridge arm of the first full-bridge circuit unit, and the other end of the second coupled inductor is connected to the other end of the first winding.

5. The wide-range output isolated bidirectional single-stage converter according to claim 4, characterized in that: The second full-bridge circuit unit comprises: a seventh switch tube and an eighth switch tube connected in series, wherein 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 a midpoint of a bridge arm of the second full-bridge circuit unit; A ninth switch tube and a tenth switch tube are connected in series, 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 the midpoint of another bridge arm of the second full-bridge circuit unit.

6. The wide-range output isolated bidirectional single-stage converter according to claim 5, characterized in that: The third full-bridge circuit unit comprises: an eleventh switch tube and a twelfth switch tube connected in series, wherein 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 a midpoint of a bridge arm of the third full-bridge circuit unit; A thirteenth switch tube and a fourteenth switch tube are connected in series, the second end of the thirteenth switch tube is connected to 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 another bridge arm of the third full-bridge circuit unit.

7. The wide-range output isolated bidirectional single-stage converter according to claim 6, characterized in that: The switching circuit unit comprises: A first switch, wherein one end of the first switch is connected to the second end of the tenth switch tube, and the other end of the first switch tube is connected to the first end of the thirteenth switch tube; a second switch, wherein one end of the second switch is connected to the first end of the ninth switch tube, and the other end of the second switch is connected to the first end of the thirteenth switch tube; A third switch, one end of the third switch is connected to the second end of the tenth switch tube, and the other end of the third switch is connected to the second end of the fourteenth switch tube.

8. The wide-range output isolated bidirectional single-stage converter according to claim 7, characterized in that: The filter circuit unit comprises: A filter inductor, one end of which is connected to the first port; A first resistor, one end of the first resistor is connected to the other end of the filter inductor, and the other end of the first resistor is connected to the center tap.

9. A control method for a wide-range output isolated bidirectional single-stage converter according to claim 8, characterized in that: The control method comprises the following steps: After receiving the control instruction, determining the control mode according to the control instruction; If it is determined to be a low-voltage rectification mode or a low-voltage inverter mode according to the control instruction, the first switch is controlled to be disconnected, and the second switch and the third switch are controlled to be turned on, and a corresponding driving signal with a duty cycle of 50% is sent to the driving end of the first to fourteenth switch tubes, so as to control only one of the two switch tubes in the same bridge arm of the first full-bridge circuit unit to be in the on state, and control only one of the two switch tubes in the half-bridge circuit unit to be in the on state, and control only one of the two switch tubes in the same bridge arm of the second full-bridge circuit unit to be in the on state, and control the third full-bridge circuit unit to be Only one of the two switch tubes in the same bridge arm is in the on state, so that the wide-range output isolated bidirectional single-stage converter operates in the rectification mode or the inverter mode, wherein when the wide-range output isolated bidirectional single-stage converter operates in the rectification mode, the drive signal corresponding to the first full-bridge circuit unit is ahead of the drive signals corresponding to the second full-bridge circuit unit and the third full-bridge circuit unit; when the wide-range output isolated bidirectional single-stage converter operates in the inverter mode, the drive signal corresponding to the first full-bridge circuit unit lags behind the drive signals corresponding to the second full-bridge circuit unit and the third full-bridge circuit unit; If it is determined to be a high-voltage rectification mode or a high-voltage inverter mode according to the control instruction, the first switch is controlled to be turned on, and the second switch and the third switch are controlled to be turned off, and a corresponding driving signal with a duty cycle of 50% is sent to the driving end of the first to fourteenth switch tubes, so as to control only one of the two switch tubes in the same bridge arm of the first full-bridge circuit unit to be in a conducting state, and control only one of the two switch tubes in the half-bridge circuit unit to be in a conducting state, and control only one of the two switch tubes in the same bridge arm of the second full-bridge circuit unit to be in a conducting state, and control only one of the two switch tubes in the same bridge arm of the third full-bridge circuit unit to be in a conducting state. Only one of the two switch tubes in the same bridge arm is in the on state, so that the wide-range output isolated bidirectional single-stage converter operates in rectification mode or inverter mode, wherein, when the wide-range output isolated bidirectional single-stage converter operates in rectification mode, the drive signal corresponding to the first full-bridge circuit unit is ahead of the drive signals corresponding to the second full-bridge circuit unit and the third full-bridge circuit unit; when the wide-range output isolated bidirectional single-stage converter operates in inverter mode, the drive signal corresponding to the first full-bridge circuit unit lags behind the drive signals corresponding to the second full-bridge circuit unit and the third full-bridge circuit unit.

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