Series-parallel connection switching circuit of bidirectional conversion module and power supply equipment

Abstract

The utility model provides a series-parallel switching circuit of a bidirectional conversion module and a power supply device, the series-parallel switching circuit comprises at least one group of parallel switching modules, at least one series switching module and a control unit, each group of parallel switching modules comprises two parallel switching units, the parallel switching unit comprises a first change-over switch and a first switching tube which are connected in parallel, and the series switching module comprises a second change-over switch, a second switching tube and a third switching tube. Switching tubes are connected in parallel to a first change-over switch and a second change-over switch, and when series-parallel connection switching is carried out, a control unit controls the corresponding switching tubes to enter a conduction state, so that the series-parallel connection change-over switch can realize low-voltage turn-off and turn-on under the clamping action of the corresponding switching tubes, the safety and reliability of the change-over switch are ensured, and the service life of the change-over switch is prolonged. Meanwhile, the bidirectional conversion module does not need to be powered off, and the power supply stability is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of circuits, in particular to a series-parallel switching circuit of a bidirectional conversion module and a power supply device. Background Art

[0002] With the rapid development of new energy and electric vehicles, products for converting and transmitting electric energy have become a market hot spot in this field. To meet the charging requirements of various vehicle models, the output voltage range must cover the battery voltage levels of various different vehicle models, and the adjustable range is, for example, from 150 to 1000V. At the same time, it is necessary to achieve maximum power output at different output voltages. Related products generally use two converters, and a series-parallel switching switch is added on the output side to achieve wide-range output. When a low voltage needs to be output, the switch for parallel switching is closed, and the switch for series switching is opened, and the two conversion modules work in parallel mode; when a high voltage needs to be output, the switch for series switching is closed, and the switch for parallel switching is opened, and the two conversion modules work in series mode. When the series-parallel switching is performed on the conversion module, since the output capacitors C1 and C2 of the two conversion modules will have a voltage mutation, the impact current generated will damage the switching switch. Therefore, when performing series-parallel switching, the conversion module is generally powered off first until the output capacitor discharges to a sufficiently low voltage level, and then the series-parallel switching is performed. This switching method will cause an interruption in the energy supply and has an adverse impact on some devices with high requirements for stable power supply. Summary of the Utility Model

[0003] The utility model provides a series-parallel switching circuit of a bidirectional conversion module and a power supply device, aiming to solve the problem that the series-parallel switching method in the related technology needs to power off the conversion module, resulting in an interruption in the energy supply.

[0004] To solve the above technical problems, a first aspect of the present utility model provides a series-parallel switching circuit for a bidirectional conversion module, including: at least one parallel switching module, at least one series switching module, and a control unit. The parallel switching module includes two parallel switching units. Each parallel switching unit includes a first switching switch and a first switching tube connected in parallel. The first switching switch of one of the parallel switching units is used to be electrically connected to the positive output terminals of two corresponding bidirectional conversion modules outside, and the first switching switch of the other parallel switching unit is used to be electrically connected to the negative output terminals of two corresponding bidirectional conversion modules outside; the series switching module includes a second switching switch, a second switching tube, and a third switching tube. The second switching switch is used to be electrically connected to the negative output terminal of a first bidirectional conversion module and the positive output terminal of a second bidirectional conversion module outside. The second switching tube and the third switching tube are connected in series, and the series branch of the second switching tube and the third switching tube is connected in parallel with the second switching switch; the control unit is electrically connected to the parallel switching module and the series switching module respectively.

[0005] A second aspect of the present utility model provides a power supply device, including a plurality of bidirectional conversion modules, a port capacitor, and the series-parallel switching circuit as described in the first aspect of the present utility model; the series-parallel switching circuit is electrically connected to the bidirectional conversion modules, and the port capacitor is electrically connected to the positive output terminal of the first bidirectional conversion module and the negative output terminal of the last bidirectional conversion module respectively.

[0006] As can be seen from the above description, in the present utility model, by connecting switching tubes in parallel to the first switching switch and the second switching switch, when performing series-parallel switching, the control unit controls the corresponding switching tubes to enter the conducting state, so that the series-parallel switching switch can achieve low-voltage turn-off and closing under the clamping action of the corresponding switching tubes, ensuring the safety and reliability of the switching switch. At the same time, it is not necessary to cut off the power supply of the bidirectional conversion module, ensuring the stability of the power supply. Description of the Drawings

[0007] Figure 1 is a schematic structural diagram of a series-parallel switching circuit according to an embodiment of the present application;

[0008] Figure 2 is a schematic circuit diagram of a series-parallel switching circuit according to an embodiment of the present application;

[0009] Figure 3 is a schematic circuit diagram of another series-parallel switching circuit according to an embodiment of the present application;

[0010] Figure 4 is a switching timing diagram for switching from the first parallel operation mode to the series operation mode according to an embodiment of the present application;

[0011] Figure 5It is the switching timing diagram for the second parallel operating mode to switch to the series operating mode in the embodiments of the present application;

[0012] Figure 6 It is the switching timing diagram for the third parallel operating mode to switch to the series operating mode in the embodiments of the present application;

[0013] Figure 7 It is the switching timing diagram for the fourth parallel operating mode to switch to the series operating mode in the embodiments of the present application;

[0014] Figure 8 It is the switching timing diagram for the fifth parallel operating mode to switch to the series operating mode in the embodiments of the present application;

[0015] Figure 9 It is the switching timing diagram for the first series operating mode to switch to the parallel operating mode in the embodiments of the present application;

[0016] Figure 10 It is the switching timing diagram for the second series operating mode to switch to the parallel operating mode in the embodiments of the present application;

[0017] Figure 11 It is the switching timing diagram for the third series operating mode to switch to the parallel operating mode in the embodiments of the present application;

[0018] Figure 12 It is the switching timing diagram for the fourth series operating mode to switch to the parallel operating mode in the embodiments of the present application;

[0019] Figure 13 It is the switching timing diagram for the fifth series operating mode to switch to the parallel operating mode in the embodiments of the present application. Detailed implementation manners

[0020] In order to make the objectives, technical solutions and advantages of the present utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model. In addition, the technical features involved in the various embodiments of the present utility model described below can be combined with each other as long as they do not conflict with each other.

[0021] In the related art, due to the problem that the series-parallel switching method requires power-off of the conversion module, resulting in interruption of energy supply, for this reason, the embodiments of the present utility model provide a series-parallel switching circuit for a bidirectional conversion module.

[0022] Such as Figure 1The following is a schematic structural diagram of a series-parallel switching circuit provided by an embodiment of the present invention. The series-parallel switching circuit includes: at least one parallel switching module 100, at least one series switching module 200, and a control unit 300; the parallel switching module 100 includes two parallel switching units 110, and the parallel switching unit 110 includes a first switching switch 111 and a first switch tube 112 connected in parallel. The first switching switch 111 of one of the parallel switching units 110 is used to be electrically connected to the positive output terminals of two corresponding external bidirectional conversion modules, and the first switching switch 111 of the other parallel switching unit 110 is used to be electrically connected to the negative output terminals of two corresponding external bidirectional conversion modules; the series switching module 200 includes a second switching switch 210, a second switch tube 220, and a third switch tube 230. The second switching switch 210 is used to be electrically connected to the negative output terminal of a corresponding first bidirectional conversion module and the positive output terminal of a second bidirectional conversion module. The second switch tube 220 and the third switch tube 230 are connected in series, and the series branch of the second switch tube 220 and the third switch tube 230 is connected in parallel with the second switching switch 210. The control unit 300 is electrically connected to the parallel switching module 100 and the series switching module 200 respectively.

[0023] Specifically, the control unit 300 is configured to: when the target output voltage is greater than the preset voltage threshold and the current output voltage is less than the voltage threshold, output a first control signal to the corresponding switch tube, and output a cut-off signal to the first switching switch 111 and a conduction signal to the second switching switch 210; when the target output voltage is less than the preset voltage threshold and the current output voltage is greater than the voltage threshold, output a second control signal to the corresponding switch tube, and output a cut-off signal to the second switching switch 210 and a conduction signal to the first switching switch 111; wherein, both the first control signal and the second control signal include a conduction signal, and both the first control signal and the second control signal are used to instruct the corresponding switch tube to enter the clamping state.

[0024] In this embodiment, the bidirectional conversion module includes a bidirectional converter and an output capacitor. The bidirectional converter can be a bidirectional AC-DC or bidirectional DC-DC. When it is necessary to achieve a wide output voltage range and meet the maximum power output, the method of connecting multiple bidirectional conversion modules in series and parallel can be adopted. In order to avoid the impact current generated by the sudden voltage of the output capacitor of the converter during the series-parallel switching from damaging the switching switch, this embodiment adopts the method of connecting a switching transistor in parallel with the switching switch. Among them, a switching transistor is connected in parallel with the first switching switch 111, and a series branch of a switching transistor is connected in parallel with the second switching switch 210. The two series-connected switching transistors form a bidirectional controllable switch, which can avoid the switching transistor from being continuously turned on in some cases and ensure the accuracy of the switching transistor control. When the required target output voltage is greater than the preset voltage threshold and the voltage currently output by the system is less than this voltage threshold, it can be determined that it is necessary to switch the current low-voltage output state to the high-voltage output state, that is, to determine to switch the current parallel mode to the series mode. At this time, the corresponding switching transistor can be controlled to enter the on state according to the type of the converter, and the first switching switch 111 is disconnected and the second switching switch 210 is closed; when the required target output voltage is less than the preset voltage threshold and the currently output voltage is greater than this voltage threshold, it can be determined that it is necessary to switch the current high-voltage output state to the low-voltage output state, that is, to switch the series mode to the parallel mode. Similarly, the corresponding switching transistor can be controlled to enter the on state according to the type of the converter, and the second switching switch 210 is disconnected and the first switching switch 111 is closed; by controlling the corresponding switching transistor to enter the on state, its clamping effect can be used to limit the voltage across the switching switch to a lower voltage, such as zero voltage, so as to achieve zero-voltage turn-off and turn-on, avoid the switching switch from being affected by the impact current, realize the series-parallel switching without power interruption, and quickly realize the application of a wide-range high-power scenario.

[0025] As Figure 2 shown is the circuit schematic diagram of a series-parallel switching circuit provided by this embodiment. Please refer to Figure 2, in this embodiment, the first switching switch 111 and the second switching switch 210 are both relays, and the switching tubes can be MOS tubes or IGBTs. Taking the first switching tubes 112 (i.e., Q1, Q2), the second switching tube 220 (i.e., Q3), and the third switching tube 230 (i.e., Q4) as MOS tubes, such as NMOS tubes, for example, both the first end and the second end of the first switching switch 111 (i.e., K1, K2) are used to be electrically connected to the corresponding bidirectional conversion module, both the first end and the second end of the second switching switch 210 (i.e., K3) are used to be electrically connected to the corresponding bidirectional conversion module, the first end (i.e., the source electrode) and the second end (i.e., the drain electrode) of the first switching tube Q1 or Q2 are respectively electrically connected to the first end and the second end of the first switching switch K1 or K2, the second ends (i.e., the drain electrodes) of the second switching tube Q3 and the third switching tube Q4 are respectively electrically connected to the first end and the second end of the second switching switch K3, the first ends (i.e., the source electrodes) of the second switching tube Q3 and the third switching tube Q4 are interconnected, the third ends (i.e., the gate electrodes) of the first switching tube Q1 or Q2, the second switching tube Q3, and the third switching tube Q4 are all electrically connected to the control unit 300, and the third ends ( Figure 2 not shown in the figure) of the first switching switch K1 or K2 and the second switching switch K3 are all electrically connected to the control unit 300; wherein, the control unit 300 can be an MCU, a DSP, etc. In addition, Figure 2 the capacitor C3 in the figure is a port capacitor, and the capacitors C1 and C2 are output capacitors of the bidirectional conversion module.

[0026] As Figure 3 shown is the circuit schematic diagram of another series-parallel switching circuit provided by this embodiment. Please refer to Figure 3 , the series-parallel switching circuit of this embodiment can be used in unidirectional converters and bidirectional converters, and can realize the series-parallel switching of two or more converters. Taking the series-parallel switching circuit of three bidirectional converters as an example, its structure is described as follows. The series-parallel switching circuit includes two groups of parallel switching modules 100 and two series switching modules 200; one of the first switching switches K1 of the first parallel switching module is respectively used to be electrically connected to the positive output terminals of the external third bidirectional conversion module and the fourth bidirectional conversion module, and the other first switching switch K4 of the first parallel switching module is respectively used to be electrically connected to the negative output terminals of the external third bidirectional conversion module and the fifth bidirectional conversion module; one of the first switching switches K3 of the second parallel switching module is respectively used to be electrically connected to the positive output terminals of the third bidirectional conversion module and the fifth bidirectional conversion module, and the other first switching switch K2 of the second parallel switching module is respectively used to be electrically connected to the negative output terminals of the fourth bidirectional conversion module and the fifth bidirectional conversion module. The first series switching module is respectively used to be electrically connected to the negative output terminal of the third bidirectional conversion module and the positive output terminal of the fourth bidirectional conversion module, and the second series switching module is respectively used to be electrically connected to the negative output terminal of the fourth bidirectional conversion module and the positive output terminal of the fifth bidirectional conversion module.

[0027] Specifically, in this embodiment, when the target output voltage is greater than the preset voltage threshold and the current output voltage is less than the voltage threshold, the control unit outputs a conduction signal to the first switch tube and the second switch tube. When the conduction duration of the first switch tube reaches the preset first duration threshold, an off signal is output to the first switching switch; when the off duration of the first switching switch reaches the preset second duration threshold, a conduction signal is output to the third switch tube; or, after the first switch tube is in the off state, the bidirectional conversion module is restricted to operate in the reverse transmission mode, and the voltage values of the output capacitors of each bidirectional conversion module are detected. When the negative terminal voltage value of the output capacitor in the first bidirectional conversion module is equal to the positive terminal voltage value of the output capacitor in the second bidirectional conversion module, or the sum of the voltage values of the output capacitors of all bidirectional conversion modules is equal to the voltage value of the port capacitor, a conduction signal is output to the third switch tube; when the conduction duration of the third switch tube reaches the preset third duration threshold, a conduction signal is output to the second switching switch.

[0028] Please refer to Figure 4 the timing diagram of the switching from the parallel operation mode to the series operation mode shown in Figure 2 Taking two bidirectional conversion modules as an example, before the switching, the system is in the parallel operation mode of low-voltage output. The first switching switches K1 and K2 are both closed and in the conduction state, the second switching switch K3 is open and in the off state, and the switch tubes Q1, Q2, Q3, and Q4 are all open and in the off state. When series-parallel switching is required, by first closing the switch tubes Q1 and Q2, the first switching switches K1 and K2 are turned off with zero voltage due to their clamping effect, so as to reduce the arcing risk of the switching switch (such as a relay); similarly, by first closing the switch tubes Q3 and Q4, the second switching switch K3 is turned on with zero voltage due to their clamping effect, reducing the arcing risk of the switching switch; among them, the closing timings of the switch tubes Q3 and Q4 are different. Q4 is closed after the first switching switches K1 and K2 are open for a certain duration, ensuring that Q4 is closed after the first switching switches K1 and K2 are completely open, so as to avoid output short circuit.

[0029] In addition, to reduce the inrush current when Q4 is closed, the closing moment of Q4 (i.e., Figure 4 t2 in Figure 4 can also be determined according to the following conditions: after Q1 and Q2 are turned off (i.e., Figure 4At this time, the impact current flowing through the switching transistor Q4 approaches 0, which can greatly increase its operating reliability. When the number of bidirectional conversion modules is three, for example Figure 3 As shown, the corresponding condition is to turn on Q6 and Q8 when the sum of the voltages of the output capacitors C1, C2, and C3 is equal to the voltage of the port capacitor C4, or to turn on Q6 and Q8 when the negative terminal voltage of the output capacitor C1 is equal to the positive terminal voltage of the output capacitor C2, and the negative terminal voltage of the output capacitor C2 is equal to the positive terminal voltage of the output capacitor C3. After the first switching switches K1 and K2 are disconnected for a certain period of time, a cut-off signal can be transmitted to Q1 and Q2 in the conducting state, and after the second switching switch K3 is closed for a certain period of time, a cut-off signal can be transmitted to Q3 in the conducting state to turn off the switching transistors in the conducting state. Thus, by Figure 4 Controlling the switching switches and switching transistors according to the switching timing shown can achieve the switching from the uninterruptible parallel operation mode to the series operation mode in the energy forward transmission or reverse transmission scenario.

[0030] Further, when the target output voltage is greater than the preset voltage threshold and the current output voltage is less than the voltage threshold, and the bidirectional conversion module operates in the forward transmission mode, the control unit outputs a cut-off signal to the first switching switch. When the cut-off duration of the first switching switch reaches the preset fourth duration threshold, a conduction signal is output to the third switching transistor. When the conduction duration of the third switching transistor reaches the preset fifth duration threshold, a conduction signal is output to the second switching switch; or, a conduction signal is output to the first switching transistor. When the conduction duration of the first switching transistor reaches the preset sixth duration threshold, a cut-off signal is output to the first switching switch. When the cut-off duration of the first switching switch reaches the fourth duration threshold, a conduction signal is output to the third switching transistor. When the conduction duration of the third switching transistor reaches the fifth duration threshold, a conduction signal is output to the second switching switch; or, a cut-off signal is output to the first switching switch. When the cut-off duration of the first switching switch reaches the fourth duration threshold, a conduction signal is output to the second switching transistor and the third switching transistor. When the conduction duration of the second switching transistor or the third switching transistor reaches the fifth duration threshold, a conduction signal is output to the second switching switch.

[0031] Specifically, in this embodiment, with the energy transfer direction from Vin to Vo as the forward transmission direction, when it is necessary to switch from the parallel operation mode to the series operation mode and the bidirectional converter is in the forward transmission mode, the optional switching timings are, for example Figure 5 , Figure 6 and Figure 7 There are three ways. In Figure 5In the switching timing shown, the switching transistors Q1, Q2, and Q3 do not need to be controlled, that is, Q1, Q2, and Q3 are continuously in the off state. At this time, the switching transistors Q1, Q2, and Q3 can be equivalent to their body diodes. When the two converters operate in parallel, the power flow is Vin+ → the first bidirectional conversion module → Vo+ → Vo- → K2 → the first bidirectional conversion module → Vin-, and Vin+ → the second bidirectional conversion module → K1 → Vo+ → Vo- → the second bidirectional conversion module → Vin-. When the first switching switches K1 and K2 are turned off, although the relay operates with current, the voltage will be clamped to 0 by the equivalent diodes, so that K1 and K2 can be turned off without power. After K1 and K2 are turned off, the system still operates in the parallel mode, and the power flow is Vin+ → the first bidirectional conversion module → Vo+ → Vo- → the equivalent diode D2 of Q2 → the first bidirectional conversion module → Vin-, and Vin+ → the second bidirectional conversion module → the equivalent diode D1 of Q1 → Vo+ → Vo- → the second bidirectional conversion module → Vin-. When the switching transistor Q4 is turned on, the diodes D1 and D2 are reverse-biased and cut off, and the current will flow through the equivalent diode D3 of Q3 and the switching transistor Q4. At this time, the system operates in the series mode, and the power flow is Vin+ → the first bidirectional conversion module → Vo+ → Vo- → the second bidirectional conversion module → Q4 → D3 → Vin-. When the second switching switch K3 is turned on, due to the clamping effect of Q4 and D3, K3 can be turned on with zero voltage, and the current flows through K3. At this time, the system operates in the series mode, and the power flow is Vin+ → the first bidirectional conversion module → Vo+ → Vo- → the second bidirectional conversion module → K3 → Vin-. Thus, when the bidirectional converter is in the forward transmission mode, the body diodes of the switching transistors Q1, Q2, and Q3 can create zero-voltage switching conditions for the switching switches. In Figure 6 In the switching timing shown, the switching transistor Q3 does not need to act during the switching stage, and its body diode provides zero-voltage turn-on conditions for the second switching switch K3. In Figure 7 In the switching timing shown, the switching transistors Q1 and Q2 do not act during the switching stage, and their body diodes provide zero-voltage turn-off conditions for the first switching switches K1 and K2. In addition, after the first switching switches K1 and K2 are turned off for a certain period of time, a cut-off signal can be transmitted to Q1 and Q2 in the conducting state, and after the second switching switch K3 is turned on for a certain period of time, a cut-off signal can be transmitted to Q3 and / or Q4 in the conducting state to turn off the conducting switching transistors.

[0032] Further, when the target output voltage is greater than the preset voltage threshold, the current output voltage is less than the voltage threshold, and the bidirectional conversion module operates in the reverse transmission mode, the control unit outputs a conduction signal to the first switching transistor and the second switching transistor. When the conduction duration of the first switching transistor reaches the preset seventh duration threshold, a cut-off signal is output to the first switching switch; when the cut-off duration of the first switching switch reaches the preset eighth duration threshold, or the conduction duration of the second switching transistor reaches the preset ninth duration threshold, a conduction signal is output to the second switching switch.

[0033] Specifically, in this embodiment, the energy transfer direction from Vo to Vin is defined as the reverse transmission direction. For example Figure 8 as shown in the switching timing diagram, when the bidirectional converter is in the reverse transmission mode, the switching transistor Q4 can remain inactive during the switching phase, and its body diode provides a zero-voltage conduction condition for the second switching switch K3. In this embodiment, the conduction and cut-off of each switching transistor can be selected according to the current flow direction. After the first switching switches K1 and K2 are disconnected for a certain duration, a cut-off signal can be transmitted to Q1 and Q2 in the conduction state, and after the second switching switch K3 is closed for a certain duration, a cut-off signal can be transmitted to Q3 and / or Q4 in the conduction state to turn off the switching transistors in the conduction state.

[0034] Similarly, in Figures 5 to 8 the switching timing diagram, at the moment t1 in the figure, by controlling the first bidirectional conversion module and the second bidirectional conversion module to operate in the reverse transmission mode, the output capacitors C1 and C2 of the bidirectional conversion module are discharged, and the voltage values of the output capacitors are detected. When the sum of the voltages of the output capacitors C1 and C2 is equal to the voltage of the port capacitor C3, or the negative terminal voltage of the output capacitor C1 is equal to the positive terminal voltage of the output capacitor C2, then Q4 or K3 is closed (at the moment t2 in the figure). At this time, the inrush current flowing through the switching transistor Q4 or K3 is close to 0, which can greatly improve its operation reliability.

[0035] Further, when the target output voltage is less than the preset voltage threshold and the current output voltage is greater than the voltage threshold, the control unit outputs a conduction signal to the second switch tube and the third switch tube. When the conduction duration of the second switch tube or the third switch tube reaches the preset tenth duration threshold, a cut-off signal is output to the second switching switch; when the cut-off duration of the second switching switch reaches the preset eleventh duration threshold, a conduction signal is output to the first switch tube; or, after the third switch tube is in the cut-off state, the bidirectional conversion module is restricted to operate in the forward transmission mode, and when the voltage values of the output capacitors in each bidirectional conversion module are equal to the voltage value of the port capacitor or the negative terminal voltage of the output capacitor in the first bidirectional converter is equal to the negative terminal voltage of the port capacitor, and the positive terminal voltage of the output capacitor in the second bidirectional converter is equal to the positive terminal voltage of the port capacitor, a conduction signal is output to the first switch tube; when the conduction duration of the first switch tube reaches the preset twelfth duration threshold, a conduction signal is output to the first switching switch.

[0036] Specifically, refer to Figure 9 the timing diagram of the switching from the series working mode to the parallel working mode shown in Figure 2 Taking two bidirectional conversion modules as an example, before the switching, the system is in the series working mode of high-voltage output, the first switching switches K1 and K2 are both disconnected, the second switching switch K3 is closed, and the switch tubes Q1, Q2, Q3, and Q4 are all disconnected; when series-parallel switching is required, by first closing the switch tubes Q3 and Q4, the second switching switch K3 is turned off at zero voltage by its clamping action to reduce the arcing risk of the switching switch (such as a relay); similarly, by first closing the switch tubes Q1 and Q2, the first switching switches K1 and K2 are turned on at zero voltage by their clamping action to reduce the arcing risk of the switching switch.

[0037] In addition, to reduce the inrush current when Q1 and Q2 are closed, Q1 and Q2 can also determine the closing moment (i.e., Figure 9 t2 in Figure 9 according to the following conditions: after Q4 is disconnected (i.e., Figure 9 t1 in Figure 3As shown, the corresponding condition is to close Q1, Q2, Q3, and Q4 when the voltages across the output capacitors C1, C2, and C3 are all equal to the voltage across the port capacitor C4, or to close Q1, Q2, Q3, and Q4 when the negative terminal voltages of the output capacitors C1 and C2 are equal to the negative terminal voltage of the port capacitor C3 and the positive terminal voltages of the output capacitors C2 and C3 are equal to the positive terminal voltage of the port capacitor C4. After the first switching switches K1 and K2 are closed for a certain period of time, a cut-off signal can be transmitted to Q1 and Q2 in the conducting state, and after the second switching switch K3 is opened for a certain period of time, a cut-off signal can be transmitted to Q3 and Q4 in the conducting state to turn off the switching transistors in the conducting state. Thus, by Figure 9 controlling the switching switches and switching transistors according to the switching timing shown, the seamless switching from the series working mode to the parallel working mode can be achieved in the scenarios of forward or reverse energy transmission.

[0038] Furthermore, when the target output voltage is less than the preset voltage threshold and the current output voltage is greater than the voltage threshold, and the bidirectional conversion module operates in the forward transmission mode, the control unit outputs a conduction signal to the third switching transistor. When the conduction duration of the third switching transistor reaches the preset thirteenth duration threshold, a cut-off signal is output to the second switching switch. When the cut-off duration of the second switching switch reaches the preset fourteenth duration threshold, a conduction signal is output to the first switching switch; or, a conduction signal is output to the second switching transistor and the third switching transistor. When the conduction duration of the second switching transistor or the third switching transistor reaches the thirteenth duration threshold, a cut-off signal is output to the second switching switch. When the cut-off duration of the second switching switch reaches the fourteenth duration threshold, a conduction signal is output to the first switching switch; or, a conduction signal is output to the third switching transistor. When the conduction duration of the third switching transistor reaches the thirteenth duration threshold, a cut-off signal is output to the second switching switch. When the cut-off duration of the second switching switch reaches the fifteenth duration threshold, a conduction signal is output to the first switching transistor. When the conduction duration of the first switching transistor reaches the preset sixteenth duration threshold, a conduction signal is output to the first switching switch.

[0039] Specifically, in this embodiment, similar to the switching from the parallel working mode to the series working mode, when the bidirectional conversion module is in the forward transmission mode, the optional switching timings are, for example Figure 10 , Figure 11 and Figure 12 There are three ways; among them, in the switching timing shown in Figure 10 , the switching transistors Q1, Q2, and Q3 do not need to be controlled, that is, Q1, Q2, and Q3 remain in the off state continuously, and the body diodes thereof provide zero-voltage switching conditions for the switching switches; in the switching timing shown in Figure 11 , the switching transistors Q1 and Q2 do not need to be controlled, and the body diodes thereof provide zero-voltage conduction conditions for the first switching switches K1 and K2; in the switching timing shown in Figure 12In the switching timing diagram shown, the switching transistor Q3 does not need to be controlled, and its body diode provides a zero-voltage turn-off condition for the second switching switch K3. In addition, after the first switching switches K1 and K2 are closed for a certain period of time, a cut-off signal can be transmitted to Q1 and Q2 in the conducting state, and after the second switching switch K3 is turned off for a certain period of time, a cut-off signal can be transmitted to the conducting Q3 and / or Q4 to turn off the conducting switching transistors.

[0040] Furthermore, when the target output voltage is less than the preset voltage threshold and the current output voltage is greater than the voltage threshold, and the bidirectional conversion module operates in the reverse transmission mode, the control unit outputs a conduction signal to the second switching transistor. When the conduction duration of the second switching transistor reaches the preset seventeenth duration threshold, a cut-off signal is output to the second switching switch; when the cut-off duration of the second switching switch reaches the preset eighteenth duration threshold, a conduction signal is output to the first switching transistor. When the conduction duration of the first switching transistor reaches the preset nineteenth duration threshold, a conduction signal is output to the first switching switch.

[0041] Specifically, in this embodiment, similar to the switching from the parallel operation mode to the series operation mode, when the bidirectional conversion module is in the reverse transmission mode, an optional switching timing is, for example Figure 13 as shown. The switching transistor Q4 can remain inactive during the switching phase, and its body diode provides a zero-voltage turn-off condition for the second switching switch K3. In this embodiment, the conduction and cut-off of each switching transistor can be selected according to the current flow direction. After the first switching switches K1 and K2 are closed for a certain period of time, a cut-off signal can be transmitted to Q1 and Q2 in the conducting state, and after the second switching switch K3 is turned off for a certain period of time, a cut-off signal can be transmitted to the conducting Q3 to turn off the conducting switching transistors.

[0042] Similarly, in the Figures 10 to 13 switching timing diagram, at time t1 in the figure, by controlling the first bidirectional conversion module and the second bidirectional conversion module to operate in the forward transmission mode, the output capacitors C1 and C2 of the bidirectional conversion module are charged, and the voltage values of the output capacitors are detected. When the voltages at both ends of the output capacitors C1 and C2 are equal to the voltage of the port capacitor C3, Q1 and Q2 (or K1 and K2) are closed, or when the negative terminal voltage of the output capacitor C1 is equal to the negative terminal voltage of the port capacitor C3 and the positive terminal voltage of the output capacitor C2 is equal to the positive terminal voltage of the port capacitor C3 (i.e., time t2 in the figure), the inrush current flowing through the switching transistors Q1 and Q2 (or K1 and K2) is close to 0, which can greatly improve the reliability of their operation.

[0043] An embodiment of the present utility model further provides a power supply device, which includes a plurality of bidirectional conversion modules, a port capacitor, and the above-mentioned series-parallel switching circuit; the series-parallel switching circuit is electrically connected to the bidirectional conversion module, and the port capacitor is respectively electrically connected to the positive output terminal of the first bidirectional conversion module and the negative output terminal of the last bidirectional conversion module. Among them, the bidirectional conversion module includes a bidirectional converter and an output capacitor, and the output capacitor is electrically connected to the bidirectional converter.

[0044] It should be noted that the various embodiments in the content of the present utility model are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other.

[0045] It should also be noted that in the content of the present utility model, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including an..." does not exclude the existence of another identical element in the process, method, article or device including the said element.

[0046] The above description of the disclosed embodiments enables those skilled in the art to implement or use the content of the present utility model. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined in the content of the present utility model can be implemented in other embodiments without departing from the spirit or scope of the content of the present utility model. Therefore, the content of the present utility model will not be limited to these embodiments shown in the content of the present utility model, but rather to the widest scope consistent with the principles and novel features disclosed in the content of the present utility model.

Claims

1. A series-parallel switching circuit of a bidirectional conversion module, characterized in that: include: at least one parallel switching module, at least one series switching module and a control unit, The parallel switching module includes two parallel switching units, each of which includes a first switching switch and a first switch tube connected in parallel, wherein the first switching switch of one of the parallel switching units is used to be electrically connected to the positive output ends of two corresponding external bidirectional conversion modules, and the first switching switch of the other parallel switching unit is used to be electrically connected to the negative output ends of the two corresponding external bidirectional conversion modules; The series switching module includes a second switch, a second switch tube and a third switch tube, the second switch is used to be electrically connected to the positive output end of the first bidirectional conversion module and the negative output end of the second bidirectional conversion module corresponding to the outside, the second switch tube is connected in series with the third switch tube, and the series branch of the second switch tube and the third switch tube is connected in parallel with the second switch; The control unit is electrically connected to the parallel switching module and the series switching module respectively.

2. The series-parallel switching circuit according to claim 1, characterized in that: The first end and the second end of the first switching switch are both used to be electrically connected to the corresponding bidirectional conversion module, the first end and the second end of the first switching tube are electrically connected to the first end and the second end of the first switching switch respectively, the third end of the first switching tube is electrically connected to the control unit, and the third end of the first switching switch is electrically connected to the control unit.

3. The series-parallel switching circuit according to claim 1, characterized in that: The first end and the second end of the second switching switch are both used to be electrically connected to the corresponding bidirectional conversion module, the first ends of the second switching tube and the third switching tube are interconnected, the second ends of the second switching tube and the third switching tube are respectively electrically connected to the first end and the second end of the second switching switch, the third ends of the second switching tube and the third switching tube are both electrically connected to the control unit, and the third end of the second switching switch is electrically connected to the control unit.

4. The series-parallel switching circuit according to claim 2 or 3, characterized in that: The first switch tube, the second switch tube and the third switch tube all include any one of the following: a MOS tube and an IGBT.

5. The series-parallel switching circuit according to claim 4, characterized in that: The first switch tube is an NMOS tube, a drain and a source of the first switch tube are electrically connected to a first end and a second end of the first switch, respectively, and a gate of the first switch tube is electrically connected to the control unit.

6. The series-parallel switching circuit according to claim 4, characterized in that: The second switch tube and the third switch tube are both NMOS tubes, the drains of the second switch tube and the third switch tube are electrically connected to the first end and the second end of the second switch, respectively, the sources of the second switch tube and the third switch tube are interconnected, and the gates of the second switch tube and the third switch tube are electrically connected to the control unit.

7. The series-parallel switching circuit according to any one of claims 1 to 6, characterized in that: The first switch and the second switch are both relays.

8. The series-parallel switching circuit according to claim 1, characterized in that: It includes two groups of the parallel switching modules and two of the series switching modules; One of the first switching switches of the first parallel switching module is used to be electrically connected to the positive output ends of the third and fourth bidirectional conversion modules, and the other of the first switching switches of the first parallel switching module is used to be electrically connected to the negative output ends of the third and fifth bidirectional conversion modules; One of the first switching switches of the second parallel switching module is respectively used to be electrically connected to the positive output ends of the third bidirectional conversion module and the fifth bidirectional conversion module, and another of the first switching switches of the second parallel switching module is respectively used to be electrically connected to the negative output ends of the fourth bidirectional conversion module and the fifth bidirectional conversion module; The first series switching module is used to be electrically connected to the negative output end of the third bidirectional conversion module and the positive output end of the fourth bidirectional conversion module, and the second series switching module is used to be electrically connected to the negative output end of the fourth bidirectional conversion module and the positive output end of the fifth bidirectional conversion module.

9. A power supply device, characterized in that: It comprises a plurality of bidirectional conversion modules, a port capacitor and a series-parallel switching circuit as described in any one of claims 1 to 8; the series-parallel switching circuit is electrically connected to the bidirectional conversion module, and the port capacitor is electrically connected to the positive output end of the first bidirectional conversion module and the negative output end of the last bidirectional conversion module, respectively.

10. The power supply device according to claim 9, characterized in that: The bidirectional conversion module includes a bidirectional converter and an output capacitor, and the output capacitor is electrically connected to the bidirectional converter.

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