CN209823644U - DCDC bidirectional conversion circuit and converter - Google Patents

Abstract

The utility model is suitable for the field of electronic technology, and provides a DCDC bidirectional conversion circuit and a converter. The circuit includes four bridge arms and two inductors, and each bridge arm includes two series-connected switch tubes and a diode connected in parallel with the two series-connected switch tubes; the common node of the two switch tubes in the first bridge arm passes through the second An inductor is connected to the common node of the two switch tubes in the third bridge arm, the anode of the diode in the first bridge arm is connected to the cathode of the diode in the second bridge arm; the common node of the two switch tubes in the fourth bridge arm passes through the first The second inductor is connected to the common node of the two switch tubes in the second bridge arm, the cathode of the diode in the fourth bridge arm is connected to the anode of the diode in the third bridge arm, and the voltage drop of the diode is smaller than that of the two switches connected in series in the corresponding bridge arm The voltage drop across the tube. The utility model can realize high-voltage bidirectional up-down and down-down double conversion, and the diode provides a freewheeling circuit in the bridge arm to reduce the voltage stress of the switch device in the bridge arm.

Description

DCDC bidirectional conversion circuit and converter

technical field

The utility model belongs to the field of electronic technology, in particular to a DCDC bidirectional conversion circuit and a converter.

Background technique

DCDC (DC-DC) converter is a DC conversion device that converts DC basic power into other voltage types, and is widely used in solar power generation, uninterruptible power supply and other fields. Its working principle is to convert DC power into another DC voltage (boost or buck).

At present, DCDC converters are more and more widely used. Different DCDC converters can be equivalent to step-up Boost converters or step-down Buck converters after simplified conversion. In the traditional DCDC converter, the energy flows in one direction, which makes the inductor current discontinuous, which is easy to cause unstable oscillation of the system, and the voltage stress of the switching device inside the converter is large, which reduces the reliability of the system.

Utility model content

In view of this, the embodiment of the present utility model provides a DCDC bidirectional conversion circuit and a converter to solve the problems of unidirectional energy flow in traditional DCDC converters and large voltage stress of internal switching devices in the prior art.

The first aspect of the embodiment of the present invention provides a DCDC bidirectional conversion circuit, including: a first bridge arm, a second bridge arm, a third bridge arm, a fourth bridge arm, a first inductor and a second inductor; each bridge arm is including two series switch tubes and a diode connected in parallel with the two series switch tubes;

The common node of the two series-connected switch tubes in the first bridge arm is connected to the common node of the two series-connected switch tubes in the third bridge arm through the first inductor, and the diode in the first bridge arm The anode is connected to the cathode of the diode in the second bridge arm; the cathode of the diode in the first bridge arm and the anode of the diode in the second bridge arm are respectively connected to both ends of the external first power supply;

The common node of the two series-connected switch tubes in the fourth bridge arm is connected to the common node of the two series-connected switch tubes in the second bridge arm through the second inductor, and the diode in the fourth bridge arm The cathode is connected to the anode of the diode in the third bridge arm; the cathode of the diode in the third bridge arm and the anode of the diode in the fourth bridge arm are respectively connected to both ends of the external second power supply;

Wherein, the voltage drop of the diode is smaller than the voltage drop across the two connected switch tubes in the corresponding bridge arm.

Optionally, the first bridge arm includes: a first switch tube, a second switch tube and a first diode;

The first end of the first switch tube is connected to the cathode of the first diode, the second end of the first switch tube is connected to the first end of the second switch tube, and the second switch The second end of the tube is connected to the anode of the first diode.

Optionally, the second bridge arm includes: a third switch tube, a fourth switch tube and a second diode;

The first end of the third switch tube is connected to the cathode of the second diode, the second end of the third switch tube is connected to the first end of the fourth switch tube, and the fourth switch tube The second end of the tube is connected to the anode of the second diode.

Optionally, the third bridge arm includes: a fifth switch transistor, a sixth switch transistor and a third diode;

The first end of the fifth switch tube is connected to the cathode of the third diode, the second end of the fifth switch tube is connected to the first end of the sixth switch tube, and the sixth switch tube The second end of the tube is connected to the anode of the third diode.

Optionally, the fourth bridge arm includes: a seventh switch tube, an eighth switch tube, and a fourth diode;

The first end of the seventh switch tube is connected to the cathode of the fourth diode, the second end of the seventh switch tube is connected to the first end of the eighth switch tube, and the eighth switch tube The second end of the tube is connected to the anode of the fourth diode.

Optionally, the switch tube is an IGBT or a MOS tube.

Optionally, the switching transistor is an N-channel IGBT or an N-channel MOS transistor.

Optionally, the DCDC bidirectional conversion circuit further includes: a first capacitor, a second capacitor, a third capacitor and a fourth capacitor;

The first end of the first capacitor is connected to the cathode of the diode in the first bridge arm, and the second end of the first capacitor is connected to the anode of the diode in the first bridge arm;

The first end of the second capacitor is respectively connected to the cathode of the diode in the second bridge arm and the second end of the first capacitor, and the second end of the second capacitor is connected to the second end of the second bridge arm. the anode connection of the diode;

The first end of the third capacitor is connected to the cathode of the diode in the third bridge arm, and the second end of the third capacitor is connected to the anode of the diode in the third bridge arm;

The first end of the fourth capacitor is respectively connected to the cathode of the diode in the fourth bridge arm and the second end of the third capacitor, and the second end of the fourth capacitor is connected to the second end of the fourth bridge arm. Anode connection of the diode.

Optionally, parameters of the first capacitor and the second capacitor are the same, and parameters of the third capacitor and the fourth capacitor are the same.

The second aspect of the embodiment of the present invention provides a DCDC bidirectional converter, including a first power supply and a second power supply, and also includes any of the first aspects of the embodiment that are connected to the first power supply and the second power supply. One of the DCDC bidirectional conversion circuits.

Compared with the prior art, the embodiment of the utility model has the following beneficial effects: the circuit mainly includes four groups of bridge arms and two inductors, each bridge arm includes two series switch tubes and is connected in parallel with two series switch tubes The diode has a simple structure and low cost, and the voltage drop of the diode is smaller than the voltage drop at both ends of the two series-connected switching tubes in the corresponding bridge arm, which provides a freewheeling circuit for the corresponding bridge arm and reduces the voltage stress of the switching device; wherein, The common node of the two series-connected switch tubes in the first bridge arm is connected to the common node of the two series-connected switch tubes in the third bridge arm through the first inductance, and the anode of the diode in the first bridge arm is connected to the diode in the second bridge arm The cathode connection of the diode in the first bridge arm and the anode of the diode in the second bridge arm are respectively connected to both ends of the external first power supply; the common node of the two series-connected switch tubes in the fourth bridge arm passes through the second inductor It is connected to the common node of the two series-connected switching tubes in the second bridge arm, and the cathode of the diode in the fourth bridge arm is connected to the anode of the diode in the third bridge arm; the cathode of the diode in the third bridge arm is connected to the anode of the diode in the fourth bridge arm The anodes of the diodes are respectively connected to the two ends of the external second power supply, realizing high-voltage bidirectional up-down and down-down double conversion.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the utility model, the following will briefly introduce the accompanying drawings that are required in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only the practical For some novel embodiments, those skilled in the art can also obtain other drawings based on these drawings without any creative work.

Fig. 1 is a schematic structural diagram of a DCDC bidirectional conversion circuit provided by an embodiment of the present invention.

Detailed ways

In the following description, specific details such as specific system structures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present invention. However, it will be apparent to those skilled in the art that the invention may be practiced in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

In order to illustrate the technical solution described in the utility model, the following specific examples will be used for illustration.

Embodiment one

Referring to FIG. 1, a DCDC bidirectional conversion circuit provided in this embodiment includes: a first bridge arm 100, a second bridge arm 200, a third bridge arm 300, a fourth bridge arm 400, a first inductor L1 and a second inductor L2. Each bridge arm includes two series switch tubes and a diode connected in parallel with the two series switch tubes. The common node of the two series-connected switching tubes in the first bridge arm 100 is connected to the common node of the two series-connected switching tubes in the third bridge arm 300 through the first inductor L1, and the anode of the diode in the first bridge arm 100 is connected to the second The cathode of the diode in the bridge arm 200 is connected; the cathode of the diode in the first bridge arm 100 and the anode of the diode in the second bridge arm 200 are respectively connected to both ends of the external first power supply V1.

The common node of the two series-connected switching tubes in the fourth bridge arm 400 is connected to the common node of the two series-connected switching tubes in the second bridge arm 200 through the second inductor L2, and the cathode of the diode in the fourth bridge arm 400 is connected to the third The anode of the diode in the bridge arm 300 is connected; the cathode of the diode in the third bridge arm 300 and the anode of the diode in the fourth bridge arm 400 are respectively connected to both ends of the external second power supply V2.

Wherein, the voltage drop of the diode of each bridge arm is smaller than the voltage drop across the two connected switch tubes in the corresponding bridge arm, and the diode provides a freewheeling circuit for the corresponding bridge arm to reduce the pressure of the switch tube.

In the DCDC bidirectional conversion circuit of this embodiment, when the voltage of the first power supply V1 is lower than the voltage of the second power supply V2, the first power supply V1 can discharge to the second power supply V2 through four sets of bridge arms, or the second power supply V2 can discharge through four sets of bridge arms. The group bridge arm discharges to the first power supply V1. It can also be realized that when the voltage of the second power supply V2 is higher than the voltage of the first power supply V1, the first power supply V1 can discharge to the second power supply V2 through four sets of bridge arms, or the second power supply V2 can discharge to the first power supply through four sets of bridge arms. The power supply V1 discharges.

In the above-mentioned DCDC bidirectional conversion circuit, each bridge arm includes two series-connected switch tubes and a diode connected in parallel with the two series-connected switch tubes. The structure is simple and the cost is low. The voltage drop at both ends of the switch tube provides a freewheeling circuit for the corresponding bridge arm, reducing the voltage stress of the switch device; wherein, the common node of the two series switch tubes in the first bridge arm 100 is connected to the first inductor L1 through the first inductor L1 The common nodes of the two series-connected switch tubes in the three bridge arms 300 are connected, and the anode of the diode in the first bridge arm 100 is connected with the cathode of the diode in the second bridge arm 200; The common node is connected to the common node of the two series-connected switching tubes in the second bridge arm 200 through the second inductor L2, and the cathode of the diode in the fourth bridge arm 400 is connected to the anode of the diode in the third bridge arm 300, realizing high-voltage bidirectional Up and down double conversion is possible.

In one embodiment, the first bridge arm 100 may include: a first switching transistor Q1, a second switching transistor Q2 and a first diode D1. The voltage drop of the first diode D1 is smaller than the voltage drop across the first switching transistor Q1 and the second switching transistor Q2 connected in series.

The first end of the first switching tube Q1 is connected to the cathode of the first diode D1, the second end of the first switching tube Q1 is connected to the first end of the second switching tube Q2, and the second end of the second switching tube Q2 Connect with the anode of the first diode D1. Since the voltage drop of the first diode D1 is smaller than the voltage drop across the first switching tube Q1 and the second switching tube Q2 connected in series (between the first end of the first switching tube Q1 and the second end of the second switching tube Q2 voltage drop), so the current between the first end of the first switching tube Q1 and the second end of the second switching tube Q2 will flow through the first diode D1, forming a freewheeling circuit, reducing the first The voltage stress of the switching tube Q1 and the second switching tube Q2.

The second bridge arm 200 may include a third switching transistor Q3, a fourth switching transistor Q4 and a second diode D2. The voltage drop of the second diode D2 is smaller than the voltage drop across the third switching transistor Q3 and the fourth switching transistor Q4 connected in series.

The first end of the third switching tube Q3 is connected to the cathode of the second diode D2, the second end of the third switching tube Q3 is connected to the first end of the fourth switching tube Q4, and the second end of the fourth switching tube Q4 Connect to the anode of the second diode D2. Since the voltage drop of the second diode D2 is smaller than the voltage drop across the third switching tube Q3 and the fourth switching tube Q4 connected in series (between the first terminal of the third switching tube Q3 and the second terminal of the fourth switching tube Q4 voltage drop), so the current between the first end of the third switching tube Q3 and the second end of the fourth switching tube Q4 will flow through the second diode D2, forming a freewheeling circuit, reducing the third The voltage stress of the switching tube Q3 and the fourth switching tube Q4.

The third bridge arm 300 may include a fifth switching transistor Q5, a sixth switching transistor Q6 and a third diode D3. The voltage drop of the third diode D3 is smaller than the voltage drop across the fifth switching transistor Q5 and the sixth switching transistor Q6 connected in series.

The first end of the fifth switching tube Q5 is connected to the cathode of the third diode D3, the second end of the fifth switching tube Q5 is connected to the first end of the sixth switching tube Q6, and the second end of the sixth switching tube Q6 It is connected with the anode of the third diode D3. Since the voltage drop of the third diode D3 is smaller than the voltage drop across the fifth switching tube Q5 and the sixth switching tube Q6 connected in series (between the first terminal of the fifth switching tube Q5 and the second terminal of the sixth switching tube Q6 voltage drop), so the current between the first end of the fifth switching tube Q5 and the second end of the sixth switching tube Q6 will flow through the third diode D3, forming a freewheeling circuit, reducing the fifth The voltage stress of the switching tube Q5 and the sixth switching tube Q6.

The fourth bridge arm 400 may include a seventh switching transistor Q7, an eighth switching transistor Q8 and a fourth diode D4. The voltage drop of the fourth diode D4 is smaller than the voltage drop across the seventh switch transistor Q7 and the eighth switch transistor Q8 connected in series.

The first end of the seventh switching tube Q7 is connected to the cathode of the fourth diode D4, the second end of the seventh switching tube Q7 is connected to the first end of the eighth switching tube Q8, and the second end of the eighth switching tube Q8 It is connected with the anode of the fourth diode D4. Since the voltage drop of the fourth diode D4 is smaller than the voltage drop across the seventh switching tube Q7 and the eighth switching tube Q8 connected in series (between the first terminal of the seventh switching tube Q7 and the second terminal of the eighth switching tube Q8 voltage drop), so the current between the first terminal of the seventh switching tube Q7 and the second terminal of the eighth switching tube Q8 will flow through the fourth diode D4, forming a freewheeling circuit, reducing the seventh The voltage stress of the switching tube Q7 and the eighth switching tube Q8.

Specifically, the common node of the two series-connected switching transistors in the first bridge arm 100 (the connection point between the second end of the first switching transistor Q1 and the first end of the second switching transistor Q2 ) and the first end of the first inductor L1 terminal connection, the common node of the two series-connected switching tubes in the third bridge arm 300 (the connection point between the second end of the fifth switching tube Q5 and the first end of the sixth switching tube Q6) and the second end of the first inductor L1 terminal connection; the common node of the two series-connected switch tubes in the second bridge arm 200 (the connection point between the second end of the third switch tube Q3 and the first end of the fourth switch tube Q4) and the first end of the second inductor L2 terminal connection, the common node of the two series-connected switching tubes in the fourth bridge arm 400 (the connection point between the second end of the seventh switching tube Q7 and the first end of the eighth switching tube Q8) and the second end of the second inductor L2 end connection.

Optionally, all the switch tubes in this embodiment may be IGBTs or MOS tubes.

Optionally, all the switch transistors in this embodiment may also be N-channel IGBTs or N-channel MOS transistors.

In an embodiment, the DCDC bidirectional conversion circuit may further include: a first capacitor C1, a second capacitor C2, a third capacitor C3 and a fourth capacitor C4.

The first end of the first capacitor C1 is connected to the cathode of the diode in the first bridge arm 100 (the cathode of the first diode D1), and the second end of the first capacitor C1 is connected to the anode of the diode in the first bridge arm 100 (the cathode of the first diode D1). The anode of a diode D1) is connected; the first end of the second capacitor C2 is respectively connected with the cathode of the diode in the second bridge arm 200 (the cathode of the second diode D2) and the second end of the first capacitor C1, The second end of the second capacitor C2 is connected to the anode of the diode in the second bridge arm 200 (the anode of the second diode D2); the first end of the third capacitor C3 is connected to the cathode of the diode in the third bridge arm 300 (the anode of the second diode D2). The cathode of the third diode D3) is connected, the second end of the third capacitor C3 is connected with the anode of the diode (the anode of the third diode D3) in the third bridge arm 300; the first end of the fourth capacitor C4 is respectively connected with the anode of the diode in the third bridge arm 300; The cathode of the diode in the fourth bridge arm 400 (the cathode of the fourth diode D4) is connected to the second end of the third capacitor C3, and the second end of the fourth capacitor C4 is connected to the anode of the diode in the fourth bridge arm 400 (the cathode of the fourth diode D4). Anodes of four diodes D4) are connected.

Optionally, the parameters of the first capacitor C1 and the second capacitor C2 are the same, and the parameters of the third capacitor C3 and the fourth capacitor C4 are the same.

The working process of the above-mentioned DCDC bidirectional conversion circuit is described in detail below in conjunction with FIG. 1:

1. When the voltage of the first power supply V1 is lower than the voltage of the second power supply V2, the specific process of discharging the first power supply V1 to the second power supply V2 through four sets of bridge arms:

The first switching tube Q1 of the first bridge arm 100, the sixth switching tube Q6 of the third bridge arm 300, the fourth switching tube Q4 of the second bridge arm 200, and the seventh switching tube Q7 of the fourth bridge arm 400 are all turned on. , the second switching tube Q2 of the first bridge arm 100, the fifth switching tube Q5 of the third bridge arm 300, the third switching tube Q3 of the second bridge arm 200, and the eighth switching tube Q8 of the fourth bridge arm 400 are all turned off. broken. At this time, the current at the first end of the first capacitor C1 (that is, the first end of the first power supply V1) passes through the first switching transistor Q1 of the first bridge arm 100, the first inductor L1, and the sixth end of the third bridge arm 300. The switch tube Q6, the seventh switch tube Q7 of the fourth bridge arm 400, the second inductor L2, and the fourth switch tube Q4 of the second bridge arm 200 return to the second end of the second capacitor C2 (that is, the first end of the first power supply V1 two ends). The current of the first inductor L1 gradually increases from left to right, and the current of the second inductor L2 gradually increases from right to left, and both the first inductor L1 and the second inductor L2 store energy.

Wherein, the first switching tube Q1 and the second switching tube Q2 of the first bridge arm 100 are not turned on at the same time, and the third switching tube Q3 and the fourth switching tube Q4 of the second bridge arm 200 are not turned on at the same time. During this process, both the first inductor L1 and the second inductor L2 release energy, and the third capacitor C3 and the fourth capacitor C4 are both charged. Since the third capacitor C3 and the fourth capacitor C4 are connected in parallel with the second power supply V2 after being connected in series, the second The third capacitor C3 and the fourth capacitor C4 charge the second power supply V2. When the current of the first inductor L1 or the second inductor L2 decreases to 0, the second switch Q2 of the first bridge arm 100 and the fifth switch Q5 of the third bridge arm 300 are both turned on, and the first bridge arm 100 The first switch tube Q1 of the third bridge arm 300 and the sixth switch tube Q6 of the third bridge arm 300 are both turned off.

When both the first switching tube Q1 of the first bridge arm 100 and the fourth switching tube Q4 of the second bridge arm 200 are turned off, the current in this process passes through the second diode D2 and the first diode D1, and there is It helps to reduce the voltage stress of the switch tube, and is good for heat dissipation.

2. When the voltage of the first power supply V1 is higher than the voltage of the second power supply V2, the specific process of discharging the first power supply V1 to the second power supply V2 through four sets of bridge arms is as follows:

The first switch tube Q1 of the first bridge arm 100 is turned on, the second switch tube Q2 of the first bridge arm 100 is turned off, the sixth switch tube Q6 of the third bridge arm 300 is turned off, and the seventh switch tube Q6 of the fourth bridge arm 400 is turned off. The switch tube Q7 is turned off, the fourth switch tube Q4 of the second bridge arm 200 is turned on, and the third switch tube Q3 of the second bridge arm 200 is turned off. At this time, the current at the first end of the first power supply V1 (that is, the first end of the first capacitor C1) passes through the first switching transistor Q1 of the first bridge arm 100, the first inductor L1, the third diode D3, the first The third capacitor C3, the fourth capacitor C4, the fourth diode D4, the second inductor L2, and the fourth switching tube Q4 of the second bridge arm 200 return to the second end of the first power supply V1.

During this process, both the first capacitor C1 and the second capacitor C2 are discharged, the third capacitor C3 and the fourth capacitor C4 are both charged, and both the first inductor L1 and the second inductor L2 store energy. The first capacitor C1 and the second capacitor C2 are connected in series between the first terminal and the second terminal of the first power supply V1, the discharge of the first capacitor C1 and the second capacitor C2 is the discharge of the first power supply V1; the third capacitor C3 After being connected in series with the fourth capacitor C4, it is connected in parallel with the second power source V2, and the third capacitor C3 and the fourth capacitor C4 are charged, that is, the second power source V2 is charged. During this process, both the first inductor L1 and the second inductor L2 store energy.

Then, the first switch tube Q1 of the first bridge arm 100 is turned off, the sixth switch tube Q6 of the third bridge arm 300 is turned off, the seventh switch tube Q7 of the fourth bridge arm 400 is turned off, and the second bridge arm 200 The fourth switching tube Q4 is turned off. At this time, the current of the first inductor L1 passes through the third diode D3, the third capacitor C3, the fourth capacitor C4, the fourth diode D4, the second inductor L2, the second diode D2, the first diode The tube D1 returns to the first inductor L1 to release energy, and both the first inductor L1 and the second inductor L2 release energy. The third diode D3 and the fourth diode D4 provide a freewheeling circuit for the corresponding bridge arm, reducing the voltage stress of the switching device.

When the voltage of the first power supply V1 is higher than the voltage of the second power supply V2, before the current of the first inductor L1 and/or the second inductor L2 crosses zero, the second switching tube Q2 of the first bridge arm 100, the third bridge The fifth switching transistor Q5 of the arm 300 , the third switching transistor Q3 of the second bridge arm 200 , and the eighth switching transistor Q8 of the fourth bridge arm 400 are turned on. When the current of the first inductor L1 or the second inductor L2 decreases to 0, the second switch tube of the first bridge arm 100 and the first switch tube of the third bridge arm 300 are both turned on, and the first switch tube of the first bridge arm 100 Both the first switching tube Q1 and the second switching tube Q2 of the third bridge arm 300 are turned off.

In the above control method, the fourth switching tube Q4 of the second bridge arm 200 corresponds to the first switching tube Q1 of the first bridge arm 100, and the fourth switching tube Q4 of the second bridge arm 200 corresponds to the second switching tube Q4 of the first bridge arm 100. Corresponding to the switching tube Q2, the eighth switching tube Q8 of the fourth bridge arm 400 corresponds to the fifth switching tube Q5 of the third bridge arm 300, and the seventh switching tube Q7 of the fourth bridge arm 400 corresponds to the sixth switching tube Q8 of the third bridge arm 300. Corresponding to the switching tube Q6.

In practical applications, if the corresponding switch tubes are controlled separately, the corresponding switch tubes adopt different duty cycle drive signals, which can be used to control the first capacitor C1 and the second capacitor C2, or the third capacitor C3 and the fourth capacitor C4. Potential balance.

Regardless of whether the voltage of the first power supply V1 is higher or lower than the voltage of the second power supply V2, the DCDC bidirectional conversion circuit of this embodiment can realize the discharge of the second power supply V2 by the first power supply V1, that is, the charging of the second power supply V2 , in this process, the first power supply V1 can be regarded as a power supply that provides power, and the second power supply V2 can be regarded as a load that consumes power.

3. When the voltage of the first power supply V1 is lower than the voltage of the second power supply V2, the specific process of discharging the second power supply V2 to the first power supply V1 through four sets of bridge arms is as follows:

The fifth switching tube Q5 of the third bridge arm 300 and the second switching tube Q2 of the first bridge arm 100 are both turned on, and the sixth switching tube Q6 of the third bridge arm 300 and the first switching tube Q1 of the first bridge arm 100 are turned on. Both are turned off, and the second switching tube Q2 of the first bridge arm 100 is turned off. During this process, both the third capacitor C3 and the fourth capacitor C4 are discharged, the first capacitor C1 and the second capacitor C2 are both charged, and the third capacitor C3 and the fourth capacitor C4 are connected in series to the first end of the second power supply V2 Between the second terminal and the second terminal, the discharge of the third capacitor C3 and the fourth capacitor C4 is the discharge of the second power supply V2; the first capacitor C1 and the second capacitor C2 are connected in parallel with the first power supply V1, and the first capacitor C1 and the second The capacitor C2 is charged, that is, the first power source V1 is charged.

When the current of the first inductor L1 or the second inductor L2 decreases to 0, the first switching tube Q1 of the first bridge arm 100 is turned on; the sixth switching tube Q6 of the third bridge arm 300 and the first switching tube Q6 of the first bridge arm 100 Both the second switching tubes Q2 are turned off, the fifth switching tube Q5 of the third bridge arm 300 and the first switching tube Q1 of the first bridge arm 100 are both turned off; or, the sixth switching tubes Q6, The first switching tube Q1 of the first bridge arm 100 is turned on, the fifth switching tube Q5 of the third bridge arm 300, and the second switching tube Q2 of the first bridge arm 100 are all turned off; the sixth switching tube Q2 of the third bridge arm 300 is turned off; Both switch tubes Q6 are turned off.

The specific current flow in this process, combined with the conduction of the switch tube, is similar to the above-mentioned current flow, and will not be described in detail.

4. When the voltage of the first power supply V1 is higher than the voltage of the second power supply V2, the specific process of discharging the second power supply V2 to the first power supply V1 through four sets of bridge arms is as follows:

The fifth switching tube Q5 of the third bridge arm 300 is turned on; the second switching tube Q2 of the first bridge arm 100 and the sixth switching tube Q6 of the third bridge arm 300 are both turned off; then the fifth switching tube Q5 of the third bridge arm 300 Both the switching tube Q5 and the second switching tube Q2 of the first bridge arm 100 are turned off. During this process, both the third capacitor C3 and the fourth capacitor C4 are discharged, the first capacitor C1 and the second capacitor C2 are both charged, and the third capacitor C3 and the fourth capacitor C4 are connected in series to the first terminal of the second power supply V2 Between the second terminal and the second terminal, the discharge of the third capacitor C3 and the fourth capacitor C4 is the discharge of the second power supply V2; the first capacitor C1 and the second capacitor C2 are connected in parallel with the first power supply V1, and the first capacitor C1 and the second The capacitor C2 is charged, that is, the first power source V1 is charged.

When the current of the first inductor L1 or the second inductor L2 decreases to 0, the sixth switching transistor Q6 of the third bridge arm 300 and the first switching transistor Q1 of the first bridge arm 100 are both turned on, and the third bridge arm 300 The fifth switching tube Q5 of the first bridge arm 100, the second switching tube Q2 of the first bridge arm 100, and the sixth switching tube Q6 of the third bridge arm 300 are all turned off; or, the first switching tube Q1 of the first bridge arm 100 is turned on, The sixth switching tube Q6 of the third bridge arm 300, the second switching tube Q2 of the first bridge arm 100, the sixth switching tube Q6 of the third bridge arm 300, and the first switching tube Q1 of the first bridge arm 100 are all turned off. .

The specific current flow direction of this process, combined with the conduction of the switch tube, is similar to the above flow direction, and will not be described in detail.

In the above embodiment, the DCDC bidirectional conversion circuit mainly includes four groups of bridge arms and two inductors, and each bridge arm includes two series-connected switching tubes and a diode connected in parallel with the two series-connected switching tubes, which has a simple structure and low cost. The voltage drop of the diode is smaller than the voltage drop at both ends of the two series-connected switching tubes in the corresponding bridge arm, which provides a freewheeling circuit for the corresponding bridge arm and reduces the voltage stress of the switching device; wherein, the two series-connected switching tubes in the first bridge arm 100 The common node of the switch tube is connected to the common node of the two series switch tubes in the third bridge arm 300 through the first inductor L1, and the anode of the diode in the first bridge arm 100 is connected to the cathode of the diode in the second bridge arm 200; The cathode of the diode in the first bridge arm 100 and the anode of the diode in the second bridge arm 200 are respectively connected to both ends of the external first power supply V1; the common node of the two series-connected switch tubes in the fourth bridge arm 400 passes through the second inductor L2 is connected to the common node of two series-connected switching tubes in the second bridge arm 200, and the cathode of the diode in the fourth bridge arm 400 is connected to the anode of the diode in the third bridge arm 300; the cathode of the diode in the third bridge arm 300 and The anodes of the diodes in the fourth bridge arm 400 are respectively connected to both ends of the external second power supply V2, realizing high-voltage bidirectional up-down and down-down double conversion.

Embodiment two

This embodiment provides a DCDC bidirectional converter, including a first power supply and a second power supply, and also includes any DCDC bidirectional conversion circuit provided in the above-mentioned embodiments connected to the first power supply and the second power supply, and also has any of the above-mentioned A beneficial effect of the DCDC bidirectional conversion circuit.

Those skilled in the art can clearly understand that for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used for illustration. In practical applications, the above-mentioned functions can be assigned to different functional units, Completion of modules means that the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment may be integrated into one processing unit, or each unit may exist separately physically, or two or more units may be integrated into one unit, and the above-mentioned integrated units may adopt hardware It can also be implemented in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the protection scope of the present application. For the specific working process of the units and modules in the above system, reference may be made to the corresponding process in the foregoing method embodiments, and details will not be repeated here.

In the above-mentioned embodiments, the descriptions of each embodiment have their own emphases, and for parts that are not detailed or recorded in a certain embodiment, refer to the relevant descriptions of other embodiments.

The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

The above-described embodiments are only used to illustrate the technical solutions of the present utility model, and are not intended to limit it; although the utility model has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still understand the foregoing The technical solutions recorded in each embodiment are modified, or some of the technical features are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present utility model, and all Should be included in the scope of protection of the present utility model.

Claims (10)

1. A DCDC bidirectional conversion circuit, comprising: the bridge comprises a first bridge arm, a second bridge arm, a third bridge arm, a fourth bridge arm, a first inductor and a second inductor; each bridge arm comprises two switching tubes connected in series and a diode connected in parallel with the two switching tubes connected in series;

   a common node of two switching tubes connected in series in the first bridge arm is connected with a common node of two switching tubes connected in series in the third bridge arm through the first inductor, and an anode of a diode in the first bridge arm is connected with a cathode of a diode in the second bridge arm; the cathode of the diode in the first bridge arm and the anode of the diode in the second bridge arm are respectively connected with two ends of an external first power supply;

   a common node of two serially connected switching tubes in the fourth bridge arm is connected with a common node of two serially connected switching tubes in the second bridge arm through the second inductor, and a cathode of a diode in the fourth bridge arm is connected with an anode of a diode in the third bridge arm; the cathode of the diode in the third bridge arm and the anode of the diode in the fourth bridge arm are respectively connected with two ends of an external second power supply;

   and the voltage drop of the diode is less than the voltage drop of two ends of two switching tubes connected in series in the corresponding bridge arm.
2. 2. The DCDC bi-directional conversion circuit of claim 1, wherein the first leg comprises: the first switch tube, the second switch tube and the first diode;

   the first end of the first switch tube is connected with the cathode of the first diode, the second end of the first switch tube is connected with the first end of the second switch tube, and the second end of the second switch tube is connected with the anode of the first diode.
3. 3. The DCDC bi-directional conversion circuit of claim 1, wherein the second leg comprises: the third switching tube, the fourth switching tube and the second diode;

   the first end of the third switching tube is connected with the cathode of the second diode, the second end of the third switching tube is connected with the first end of the fourth switching tube, and the second end of the fourth switching tube is connected with the anode of the second diode.
4. 4. The DCDC bi-directional conversion circuit of claim 1, wherein the third bridge arm comprises: a fifth switching tube, a sixth switching tube and a third diode;

   the first end of the fifth switching tube is connected with the cathode of the third diode, the second end of the fifth switching tube is connected with the first end of the sixth switching tube, and the second end of the sixth switching tube is connected with the anode of the third diode.
5. 5. The DCDC bi-directional conversion circuit of claim 1, wherein the fourth leg comprises: a seventh switching tube, an eighth switching tube and a fourth diode;

   a first end of the seventh switching tube is connected with a cathode of the fourth diode, a second end of the seventh switching tube is connected with a first end of the eighth switching tube, and a second end of the eighth switching tube is connected with an anode of the fourth diode.
6. 6. The DCDC bidirectional conversion circuit according to any one of claims 2 to 5, wherein said switching tube is an IGBT or MOS tube.
7. 7. The DCDC bidirectional conversion circuit of claim 6, wherein said switching transistor is an N-channel IGBT or an N-channel MOS transistor.
8. 8. The DCDC bi-directional conversion circuit of claim 1, wherein the DCDC bi-directional conversion circuit further comprises: the first capacitor, the second capacitor, the third capacitor and the fourth capacitor;

   the first end of the first capacitor is connected with the cathode of the diode in the first bridge arm, and the second end of the first capacitor is connected with the anode of the diode in the first bridge arm;

   a first end of the second capacitor is respectively connected with a cathode of the diode in the second bridge arm and a second end of the first capacitor, and a second end of the second capacitor is connected with an anode of the diode in the second bridge arm;

   the first end of the third capacitor is connected with the cathode of the diode in the third bridge arm, and the second end of the third capacitor is connected with the anode of the diode in the third bridge arm;

   and a first end of the fourth capacitor is respectively connected with a cathode of the diode in the fourth bridge arm and a second end of the third capacitor, and a second end of the fourth capacitor is connected with an anode of the diode in the fourth bridge arm.
9. 9. The DCDC bi-directional conversion circuit of claim 8, wherein the first capacitor and the second capacitor have the same parameters, and the third capacitor and the fourth capacitor have the same parameters.
10. A DCDC bidirectional converter comprising a first power supply and a second power supply, further comprising the DCDC bidirectional converter circuit according to any one of claims 1 to 9 connected to the first power supply and the second power supply.