WO2023193764A1

WO2023193764A1 - Power conversion circuit and control method

Info

Publication number: WO2023193764A1
Application number: PCT/CN2023/086599
Authority: WO
Inventors: 张丽敏; 雷彪; 卢楷轩; 吕华军
Original assignee: 深圳英飞源技术有限公司
Priority date: 2022-04-07
Filing date: 2023-04-06
Publication date: 2023-10-12
Also published as: CN114785095A

Abstract

The present invention provides a power conversion circuit and a control method. The power conversion circuit comprises: a main loop composed of a first power circuit, a second power circuit, a switching circuit and a main loop switch; and an auxiliary loop composed of a sampling circuit, a discharging circuit and a soft start circuit. A soft start switch is added to the auxiliary loop to control the on-off of the soft start circuit; when the switch circuit controls the first power circuit and the second power circuit to switch between a series mode and a parallel mode, and when the soft start switch and the main loop switch are turned off, a second port can be completely disconnected from an internal circuit, so that the voltage of the second port is not affected by discharging and series-parallel switching of an internal capacitor, and no damage is caused to a load at the second port; moreover, an energy storage element at the second port does not charge the internal capacitor during discharging, and the voltage of an internal battery can thus be completely discharged.

Description

A power conversion circuit and control method

Technical field

The invention belongs to the field of power electronics technology, and in particular relates to a power conversion circuit and a control method.

Background technique

The traditional power conversion circuit is shown in Figure 1. In order to achieve a wide constant power voltage range, the switching states of switches K1, K2, and K3 are generally controlled so that the outputs of power circuit 1 and power circuit 2 work in series or parallel mode. When the output voltage is low, K1 is open, K2, K3 are closed, and power circuit 1 and power circuit 2 work in parallel mode; when the output voltage is high, K1 is closed, K2, K3 are open, power circuit 1 and power circuit 1 2 works in series mode.

Disadvantages of existing technology:

Generally, the main loop filter circuit contains at least a filter capacitor and a filter inductor, and the capacity of the filter capacitor is much smaller than C1 and C2. When working in parallel mode, the voltage across the filter capacitor is the same as the voltage across C1 and C2. When working in series mode, the voltage across the filter capacitor is the sum of the voltages across C1 and C2. Therefore, when the working mode is switched from parallel mode to series mode, the voltage across the filter capacitor will rise. This high voltage will flow back to the DC port through the soft-start circuit, possibly damaging the load connected to the DC port. When switching from series mode to parallel mode, if the voltages at both ends of C1 and C2 are inconsistent, a large current will flow through the switches K2 and K3. In severe cases, the contacts of K2 and K3 may be stuck. Therefore, it is hoped that the power on the capacitors C1, C2 and the filter capacitor will be completely discharged before the switches K1, K2, and K3 operate. However, when DC+ and DC- are connected to energy storage components such as batteries, even though the main circuit switch K4 is turned off, while C1, C2 and filter capacitors are being discharged, The battery is also charging the capacitor through the soft-start circuit, so it is difficult to completely discharge the internal capacitor. In addition, there are also defects in the voltage sampling scheme in the existing technical solutions: in parallel mode, the voltage of the upper half branch and the lower half branch is the same, which is the output result of sampling circuit 1 or sampling circuit 2; in series mode, the result of sampling circuit 1 is For the lower half branch voltage, the result of sampling circuit 2 minus sampling circuit 1 is the upper half branch voltage. However, when K1, K2, and K3 are all disconnected, the upper half branch voltage cannot be sampled, so the discharge of capacitor C1 cannot be judged in this case.

Finally, when K1, K2, and K3 are all disconnected, the discharge circuit cannot discharge C1 and C2.

technical problem

The technical problem to be solved by the present invention is to provide a power conversion circuit and a control method. It is intended to solve the problem in the existing technical solution that in order to achieve a wide constant power voltage range, the power conversion circuit cannot completely discharge the capacitor power during the mode switching process, resulting in switch adhesion.

Technical solutions

In order to solve the above technical problems, the present invention is implemented as follows:

A first aspect of the present invention provides a power conversion circuit for realizing power transmission between a first port and a second port. The power conversion circuit includes: a main loop and an auxiliary loop; wherein:

The main circuit includes a first power circuit, a second power circuit, a switching circuit and a main circuit switch;

The first power circuit and the second power circuit are used to realize power conversion in the power conversion circuit, wherein the output end of the first power circuit is connected in parallel with a first output capacitor, and the output end of the second power circuit is connected in parallel with a second output capacitor. output capacitor;

Switching circuit for realizing series connection between the first power circuit and the second power circuit mode or parallel mode switching;

Main circuit switch, used to control the main circuit on and off;

The auxiliary circuit includes sampling circuit, discharge circuit, soft start circuit and soft start switch;

a sampling circuit for sampling the capacitance voltage of the first output capacitor and the second output capacitor;

a discharge circuit, used to discharge the capacitance of the first output capacitor and the second output capacitor;

Soft start circuit is used to perform soft start control on the main circuit when the main circuit switch is closed;

Soft start switch is used to control the soft start circuit on and off.

Further, the sampling circuit includes:

The first sampling circuit is used to sample and obtain the voltage of the second output capacitor;

a second sampling circuit, used to sample and obtain the positive voltage of the first output capacitor;

The third sampling circuit is used to sample and obtain the negative voltage of the first output capacitor.

Furthermore, it also includes a filter circuit, which is arranged in the main circuit and used to filter out ripples in the output voltage.

Further, the first power conversion circuit and the second power conversion circuit are located at the first port and are respectively connected to independent buses, or share the same bus.

Further, it also includes an auxiliary power supply, the auxiliary power supply is connected to the second port, and the second port is used to connect the energy storage device, wherein the auxiliary circuit can also be connected to other power supplies.

Further, a balancing circuit is included, and the balancing circuit is connected in parallel to both ends of the first output capacitor for balancing impedances on the first output capacitor and the second output capacitor.

Further, the discharge circuit includes a first discharge circuit, a second discharge circuit and a third discharge circuit,

The first discharge circuit is connected in parallel to the main circuit and is used to discharge the first output capacitor and the second output capacitor when the switch circuit is connected;

a second discharge circuit, connected in parallel to both ends of the first output capacitor, for discharging the first output capacitor when the switch circuit is closed;

The third discharge circuit is connected in parallel to both ends of the second output capacitor, and is used to discharge the second output capacitor when the switch circuit is closed.

A second aspect of the present invention provides a control method, which is applied to the above power conversion circuit and used to realize the startup process of the power conversion circuit. The control method includes:

Control the main circuit switch and the soft start switch to enter the disconnected state, and the discharge circuit discharges the first output capacitor and the second output capacitor;

At the end of the discharge, control the switching circuit on and off according to the target operating mode, and control the soft-start switch to enter the conductive state to precharge the first output capacitor and the second output capacitor;

When precharging is completed, the main circuit switch is controlled to enter the conductive state, and the first power circuit and the second power circuit are controlled to enter the open state.

A third aspect of the present invention provides a control method, which is applied to the above power conversion circuit and used to realize the working mode conversion process of the power conversion circuit. The control method includes:

When the power conversion circuit is in the powered-on state, the first power circuit and the second power circuit are controlled to enter the closed state, and the main circuit switch and the soft-start switch are controlled to enter the disconnected state. The discharge circuit performs operations on the first output capacitor and the second output capacitor. discharge;

When the capacitance voltages of the first output capacitor and the second output capacitor are less than the capacitance voltage threshold, Control the on and off of the switch circuit to trigger switching of the connection mode of the first power circuit and the second power circuit; wherein the connection mode includes a series mode and a parallel mode;

Control the soft start switch to enter the conduction state, charge the first output capacitor and the second output capacitor, then turn on the main circuit switch when the charging voltage reaches the charging voltage threshold, and control the first power circuit and the second power circuit to enter the turn-on state state.

A fourth aspect of the present invention provides a control method, which is applied to the above power conversion circuit and used to realize the shutdown process of the power conversion circuit. The control method includes:

Control the first power circuit and the second power circuit to enter a closed state, and the current in the power conversion circuit gradually decreases;

When the currents passing through the main circuit switch and the soft-start switch both reduce to the current threshold, the discharge circuit is controlled to discharge the first output capacitor and the second output capacitor to complete the shutdown of the power conversion circuit.

beneficial effects

The present invention provides a power conversion circuit and a control method. Compared with the prior art, the beneficial effect is that the power conversion circuit includes a main circuit composed of a first power circuit, a second power circuit, a switching circuit and a main circuit switch, and An auxiliary circuit composed of a sampling circuit, a discharge circuit and a soft-start circuit, in which the soft-start circuit is configured with a soft-start switch; based on the control method adopted by the power conversion circuit, the switch circuit controls the first power circuit and the second power circuit to be connected in series / When switching to parallel mode, when the soft start switch and the main circuit switch are disconnected, the third port can be completely disconnected from the internal circuit. Discharging the internal capacitor and switching between series and parallel will not affect the voltage of the second port and will not cause the third port to switch. The load at the second port is damaged. At the same time, the energy storage element at the second port will not charge the internal capacitor during discharge, and the internal battery voltage can be completely discharged.

Description of the drawings

Figure 1 is a schematic structural diagram of a traditional power conversion circuit;

Figure 2 is a first embodiment of a power conversion circuit in the first embodiment of the present invention;

Figure 3 is the second embodiment of the power conversion circuit in the first embodiment of the present invention;

Figure 4 is the third embodiment of the power conversion circuit in the first embodiment of the present invention;

Figure 5 is the fourth embodiment of the power conversion circuit in the first embodiment of the present invention;

Figure 6 is the fifth embodiment of the power conversion circuit in the first embodiment of the present invention;

Figure 7 is a schematic flow chart of the control method in the second embodiment of the present invention;

Figure 8 is a specific flow diagram of the control method in the second embodiment of the present invention;

Figure 9 is a schematic flow chart of the control method in the third embodiment of the present invention;

Figure 10 is a specific flow diagram of the control method in the third embodiment of the present invention;

Figure 11 is a schematic flow chart of the control method in the fourth embodiment of the present invention;

Figure 12 is a specific flow diagram of the control method in the fourth embodiment of the present invention.

Embodiments of the invention

In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention and are not intended to limit the present invention.

Example 1

A first embodiment of the present invention provides a power conversion circuit for realizing energy transmission between a first port and a second port. In some embodiments, the first port may be a BUS port, the second port may be a DC port, and the load connected to the DC end may be an energy storage element. The present invention provides The power conversion circuit provided is used to realize energy transmission between the BUS port and the DC port.

The schematic structural diagram of the power conversion circuit shown in Figure 2; the power conversion circuit includes: a main circuit and an auxiliary circuit; where:

The main circuit includes a first power circuit 10, a second power circuit 20, a switch circuit (shown in FIG. 2 including a first switch K1, a second switch K2 and a third switch K3) and a main circuit switch K4.

Specifically, the first power circuit 10 and the second power circuit 20 are disposed at the BUS port and are connected to the power supply for power conversion. In some embodiments, the BUS port includes a first BUS port and a second BUS port, where the first The power circuit 10 is connected to the first BUS port, the second power circuit 20 is connected to the second BUS port, and a first output capacitor C1 is connected in parallel to the output end of the first power circuit 10, and to the source end of the second power circuit 20 A second output capacitor C2 is connected in parallel.

A switching circuit is used to realize switching between the first power circuit 10 and the second power circuit 20 in series mode or parallel mode. In some embodiments, the switch circuit includes a first switch K1, a second switch K2, and a third switch K3, and meets the following requirements: when the output voltage is low, the first switch K1 is turned off, the second switch K2, and the third switch K3 closed, at this time the first power circuit 10 and the second power circuit 20 work in parallel mode; when the output voltage is low, the first switch K1 is closed, the second switch K2 and the third switch K3 are open, at this time the first power The circuit 10 and the second power circuit 20 operate in series mode.

The main circuit switch K4 is set in the main circuit to control the on/off of the main circuit.

The auxiliary circuit includes a sampling circuit (shown in Figure 2 including a first sampling circuit 30, a second sampling circuit 50 and a third sampling circuit 40), a discharge circuit (shown in Figure 2 including a first discharging circuit Circuit 60), soft start circuit 80 and soft start switch K5;

Specifically, the sampling circuit is used to sample the capacitor voltage in the main circuit. In some embodiments, the sampling circuit includes a first sampling circuit 30, a second sampling circuit 50 and a third sampling circuit 40, wherein the first sampling circuit 30 is used to sample and obtain the voltage of the second output capacitor C2, and the second sampling circuit 50 is used to sample and obtain the positive electrode voltage of the first output capacitor C1, and the third sampling circuit 40 is used to sample and obtain the negative electrode voltage of the first output capacitor C1. Through the voltage sampling of the first sampling circuit 30, the second sampling circuit 50 and the third sampling circuit 40, the voltage values of the first output capacitor C1 and the second output capacitor C2 can be calculated and obtained, and judgment and control can be made based on the voltage values. The on and off of the switch in the switching circuit.

The discharge circuit is used to discharge the capacitance of the first output capacitor C1 and the second output capacitor C2. In some embodiments, only the first discharge circuit 60 is provided in the power circuit. The first discharge circuit 60 is connected between the positive terminal and the negative terminal of the DC terminal, and can complete the capacitor charging when the power conversion circuit is in series mode or parallel mode. of release.

The soft start circuit 80 is used to perform soft start control on the main circuit when the main circuit switch K4 is closed.

The soft start switch K5 is connected in series with the soft start circuit 80 and is arranged between the first discharge circuit 60 and the DC port. The soft start switch K5 is used to control the on/off of the soft start circuit.

In some embodiments, the power conversion circuit further includes a filter circuit 70 for filtering out ripples in the rectified output voltage during power transmission, where the filter circuit 70 is disposed between the first discharge circuit 60 and the soft start circuit 80 between.

Referring to Figure 3, Figure 3 shows one embodiment of the power conversion circuit of the present invention. Based on the circuit structure shown in Figure 2, the first power circuit 10 and the second power circuit are changed. The connection mode of the primary side of path 20 (sampling circuit is not shown in the figure). Among them, the primary sides of the first power circuit 10 and the second power circuit 20 share a bus. In other embodiments, the primary sides of the first power circuit 10 and the second power circuit 20 are connected to two independent buses, which also achieves The purpose of energy transmission between the BUS end and the DC end.

Referring to Figure 4, Figure 4 shows one embodiment of the power conversion circuit of the present invention. Based on the circuit structure shown in Figure 2, an auxiliary power supply 90 is added. The auxiliary power supply 90 is connected to the DC terminal, and the DC terminal is used to connect the energy storage device. The auxiliary power supply 90 can draw power from the DC port, so that the operation of the auxiliary power supply 90 is not affected when discharging the first output capacitor C1 and the second output capacitor C2. In some other implementations, the auxiliary power supply 90 can also be connected to other power supply sources. In addition to drawing power from the DC port, it can also draw power from other power supply sources.

Referring to Figure 5, Figure 5 shows one embodiment of the power conversion circuit of the present invention. Based on the circuit structure shown in Figure 4, a balancing circuit 100 is added, wherein the balancing circuit 100 is connected in parallel to both ends of the first output capacitor. end. The first sampling circuit 30, the second sampling circuit 50 and the third sampling circuit 40 are generally composed of voltage dividing resistors. In the series mode, the first sampling circuit 30 and the third sampling circuit 40 are connected to the second output capacitor C2, resulting in soft When precharging is started, the voltages on the first output capacitor C1 and the second output capacitor C2 are inconsistent. The voltage of the first output capacitor C1 is higher and the voltage of the second output capacitor C2 is lower. Therefore, the voltage across the first output capacitor C1 A balancing circuit 100 is added to make the impedances connected to the first output capacitor C1 and the second output capacitor C2 equal.

Referring to Figure 6, Figure 6 shows one embodiment of the power conversion circuit of the present invention. Based on the circuit structure shown in Figure 5, a second discharge circuit 200 and a third discharge circuit 300 are added. Wherein, the second discharge circuit 200 is connected in parallel to both ends of the first output capacitor C1, The second discharge circuit 300 is connected in parallel to both ends of the second output capacitor C2, so that the first switch K1, the second switch K2 and the third switch K3 can discharge the first output capacitor C1 and the second output capacitor respectively when the first switch K1, the second switch K2 and the third switch K3 are turned off. C2 discharges.

In summary, the present invention provides a power conversion circuit, based on which the power conversion circuit can realize: when the switch circuit controls the first power circuit and the second power circuit to switch between the series mode or the parallel mode, when the soft start switch and the main circuit switch are turned off Open, the second port can be completely disconnected from the internal circuit. Discharging the internal capacitor and switching between series and parallel will not affect the voltage of the second port and will not cause damage to the load of the second port. At the same time, the energy storage of the second port during discharge The component will not charge the internal capacitor and can completely discharge the internal battery voltage.

Example 2

The second embodiment of the present invention provides a control method, which is applied to the power conversion circuit of Embodiment 1 to realize the startup process of the power conversion circuit. The circuit structure will not be described again. As shown in Figure 7, the boot process includes:

Step 701, control the main circuit switch K4 and the soft start switch K5 to enter the off state, and the discharge circuit discharges the first output capacitor C1 and the second output capacitor C2;

Step 702: At the end of the discharge, control the switching circuit on and off according to the target operating mode, and control the soft-start switch K5 to enter the conductive state to precharge the first output capacitor C1 and the second output capacitor C2;

Step 703: When precharging is completed, control the main circuit switch K4 to enter the on state, and control the first power circuit 10 and the second power circuit 20 to enter the on state.

During the discharging process in step 703, it can be determined according to the first output capacitor C1, the second output capacitor C2 and the total voltage V _AB whether the fault is caused by the disconnection of the first switch K1, the second switch K2 and the third switch K3. The first output capacitor C1 or the second output capacitor C2 cannot be discharged. If so, the corresponding switch is turned on and continues to discharge.

After the first discharge, if the voltages of the first output capacitor C1 and the second output capacitor C2 drop at a similar rate, and the total voltage V _AB is approximately equal to Vc ₁ + Vc ₂ , it can be determined that the first switch K1 is turned on at this time, The second switch K2 and the third switch K3 are turned off; if the voltage drop rate of the first output capacitor C1 is slow, it can be considered that the first switch K1 and the second switch K2 are turned off, and the third switch K3 is turned on; if the second output capacitor C2 The voltage drop rate is slow, it can be considered that the first switch K1 and the third switch K3 are turned off, and the second switch K2 is turned on; if the voltage drop rates of the first output capacitor C1 and the second output capacitor C2 are both slow, it can be considered that the The first switch K1, the second switch K2 and the third switch K3 are all turned off. For the latter three cases, which switches to engage for discharge are determined based on the voltage values of the first output capacitor C1 and the second output capacitor C2. If the voltages of the first output capacitor C1 and the second output capacitor C2 are not much different, the second switch K2 and the third switch K3 can be turned on, the first switch K1 can be turned off, and then discharge is performed; if the first output capacitor C1 and the third output capacitor C2 are The voltage difference of the second output capacitor C2 is large, so the first switch K1 can only be turned on, the second switch K2 and the third switch K3 can be turned off, and then the

Carry out discharge.

At the end of the discharge, the switch switching module is controlled to be on and off according to the target operating mode, and the soft start switch K5 is controlled to enter the conductive state to precharge the first output capacitor C1, the second output capacitor C2 and the capacitor in the filter circuit 70.

The opening process can be seen in the specific flow chart shown in Figure 8.

Example 3

The third embodiment of the present invention provides a control method, which is applied to the power conversion circuit of Embodiment 1 to realize the conversion process of the working mode of the power conversion circuit. The circuit structure will not be described again. As shown in Figure 9, the conversion process of this working mode includes:

Step 801: When the power conversion circuit is in the powered-on state, control the first power circuit 10 and the second power circuit 20 to enter the off state, and control the main circuit switch K4 and the soft start switch K5 to enter the off state, and the discharge circuit 60 The output capacitor C1 and the second output capacitor C2 are discharged;

Step 802: When the capacitance voltages of the first output capacitor C1 and the second output capacitor C2 are less than the capacitance voltage threshold, control the on and off of the switch circuit to trigger switching of the connection mode of the first power circuit 10 and the second power circuit 20;

Step 803, control the soft-start switch to enter the on state, charge the first output capacitor C1 and the second output capacitor C2, then turn on the main circuit switch when the charging voltage reaches the charging voltage threshold, and control the first power circuit 10 and The second power circuit 20 enters the on state.

The control method is a process of switching the working modes of the first power circuit 10 and the second power circuit 20 when the power conversion circuit is in an on state; wherein, the working modes include a series mode and a parallel mode. The switching process can be seen in the specific flow chart shown in Figure 10. This switching process completely disconnects the DC port from the internal circuit. Discharging the internal capacitor and switching between series and parallel will not affect the DC port voltage or cause damage to the DC port load. At the same time, the battery at the DC port will not damage the internal capacitor during discharge. To charge, the internal battery can be The voltage is completely discharged.

Example 4

The fourth embodiment of the present invention provides a control method, which is applied to the power conversion circuit of Embodiment 1 to realize the shutdown process of the power conversion circuit. The circuit structure will not be described again. As shown in Figure 11, the conversion process of this working mode includes:

Step 901, control the first power circuit 10 and the second power circuit 20 to enter a closed state, and the current in the power conversion circuit gradually decreases;

Step 902, when the currents passing through the main circuit switch K4 and the soft-start switch K5 both reduce to the current threshold, the discharge circuit 60 is controlled to discharge the first output capacitor C1 and the second output capacitor C2 to complete the shutdown of the power conversion circuit.

It should be noted that this shutdown process is suitable for the shutdown process of the power conversion circuit and does not only need to be shut down after switching the working mode. The shutdown process can be seen in the specific flow chart of Figure 12.

The above Embodiment 2, Embodiment 3 and Embodiment 4 include the startup process, mode switching process and shutdown process of the power conversion circuit. During the startup process of the power conversion circuit, the main circuit switch K4 can be turned off after the main circuit switch K4 is turned on. Start switch K5; during the closing process of the power conversion circuit, the soft start switch K5 can be turned off before the first and second power circuits are closed, without affecting the reliability of the circuit. That is, the soft start switch K5 only needs to be turned off when the main circuit switch K4 is turned on, and it has little to do with whether the main power circuit is working or not.

To sum up, the present invention provides a control method. Compared with the existing technology, the beneficial effects are:

A sampling circuit is provided that can sample the first output capacitor and the second output capacitor in the present invention when all switches in the switching circuit are turned off; by adding a soft-start switch K5 in the auxiliary circuit, when the DC side of the module is discharged , when the main circuit switch and soft start switch K5 are disconnected, the DC port can be completely disconnected from the internal circuit. Discharging the internal capacitor and switching between series and parallel will not affect the DC port voltage and will not cause damage to the DC port load. When discharging at the same time The battery in the DC port will not charge the internal capacitor and can completely discharge the internal battery voltage.

The first, second... here only represent the distinction between their names, and do not represent any difference in their importance and position.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention. Inside.

Claims

A power conversion circuit used to realize energy transmission between a first port and a second port, characterized in that it includes: a main loop and an auxiliary loop; wherein:

The main circuit includes a first power circuit, a second power circuit, a switching circuit and a main circuit switch;

The first power circuit and the second power circuit are used to implement power conversion in a power conversion circuit, wherein the output end of the first power circuit is connected in parallel with a first output capacitor, and the second power circuit The output terminal is connected in parallel with a second output capacitor;

The switch circuit is used to realize switching between the first power circuit and the second power circuit in series mode or parallel mode;

The main circuit switch is used to control the on/off of the main circuit;

The auxiliary circuit includes a sampling circuit, a discharge circuit, a soft-start circuit and a soft-start switch;

The sampling circuit is used to sample the capacitance voltage of the first output capacitor and the second output capacitor;

The discharge circuit is used to discharge the capacitance of the first output capacitor and the second output capacitor;

The soft start circuit is used to perform soft start control on the main circuit when the main circuit switch is closed;

The soft start switch is used to control the on/off of the soft start circuit.
The power conversion circuit according to claim 1, characterized in that the sampling circuit includes: a first sampling circuit, a second sampling circuit and a third sampling circuit;

The first sampling circuit is used to sample and obtain the voltage of the second output capacitor;

The second sampling circuit is used to sample and obtain the positive voltage of the first output capacitor;

The third sampling circuit is used to sample and obtain the negative voltage of the first output capacitor.
The power conversion circuit according to claim 1, further comprising a filter circuit disposed in the main circuit for filtering out ripples in the output voltage.
The power conversion circuit according to claim 2, characterized in that the first power conversion circuit and the second power conversion circuit are respectively connected to independent buses at the first port, or share the same bus.
The power conversion circuit according to claim 3, further comprising an auxiliary power supply connected to the second port, the second port being used to connect an energy storage device, wherein the auxiliary power supply further Can be connected to other power supplies.
The power conversion circuit according to claim 4, further comprising a balancing circuit connected in parallel to both ends of the first output capacitor for balancing the first output capacitor and the second output. The impedance on the capacitor.
The power conversion circuit according to claim 5, characterized in that the discharge circuit includes a first discharge circuit, a second discharge circuit and a third discharge circuit;

The first discharge circuit is connected in parallel to the main circuit and is used to discharge the first output capacitor and the second output capacitor when the switch circuit is connected;

The second discharge circuit is connected in parallel to both ends of the first output capacitor and is used to discharge the first output capacitor when the switch circuit is closed;

The third discharge circuit is connected in parallel to both ends of the second output capacitor, and is used to discharge the second output capacitor when the switch circuit is closed.
A control method for realizing the startup process of a power conversion circuit, which is characterized by: When applied to the power conversion circuit of any one of claims 1-7, the control method includes:

Control the main circuit switch and the soft-start switch to enter a disconnected state, and the discharge circuit discharges the first output capacitor and the second output capacitor;

At the end of discharge, control the on-off of the switch circuit according to the target operating mode, control the soft-start switch to enter the conductive state, and precharge the first output capacitor and the second output capacitor;

When precharging is completed, the main circuit switch is controlled to enter the on state, and the first power circuit and the second power circuit are controlled to enter the on state.
A control method for realizing the working mode conversion process of a power conversion circuit, characterized in that it is applied to the power conversion circuit of any one of claims 1-7, and the control method includes:

When the power conversion circuit is in the powered-on state, the first power circuit and the second power circuit are controlled to enter the off state, and the main circuit switch and the soft start switch are controlled to enter the off state, and the discharge The circuit discharges the first output capacitor and the second output capacitor;

When the capacitance voltage of the first output capacitor and the second output capacitor is less than the capacitance voltage threshold, the switching circuit is controlled to be on and off, triggering switching of the connection mode of the first power circuit and the second power circuit. ; Wherein, the connection mode includes a series mode and a parallel mode;

Control the soft start switch to enter a conductive state, charge the first output capacitor and the second output capacitor, then turn on the main circuit switch when the charging voltage reaches the charging voltage threshold, and control the third output capacitor. One power circuit and the second power circuit enter the turn-on state.
A control method for realizing the shutdown process of a power conversion circuit, characterized in that it is applied to the power conversion circuit of any one of claims 1-7, and the control method includes:

Control the first power circuit and the second power circuit to enter a closed state, and the current in the power conversion circuit gradually decreases;

When the currents passing through the main circuit switch and the soft-start switch both reduce to the current threshold, the discharge circuit is controlled to discharge the first output capacitor and the second output capacitor to complete the power conversion. circuit closure.