CN114274826B

CN114274826B - Direct-current voltage output switching circuit, switching method and charging pile power module

Info

Publication number: CN114274826B
Application number: CN202111599284.7A
Authority: CN
Inventors: 江冯林
Original assignee: Sungrow Power Supply Co Ltd
Current assignee: Sungrow Power Supply Co Ltd
Priority date: 2021-12-24
Filing date: 2021-12-24
Publication date: 2024-06-21
Anticipated expiration: 2041-12-24
Also published as: CN114274826A

Abstract

The invention discloses a direct-current voltage output switching circuit, a switching method and a charging pile power module. The direct-current voltage output switching circuit comprises at least two groups of direct-current voltage input ends, at least two input storage units, a direct-current voltage output end, an output storage unit, a switch switching unit and a current limiting unit; each input storage unit is connected in parallel between two poles of a direct-current voltage input end, each output storage unit is connected in parallel between two poles of a direct-current voltage output end, each switch switching unit is connected with the direct-current voltage input end, each current limiting unit is connected in series between the direct-current voltage input end and the direct-current voltage output end, each switch switching unit is used for switching the connection state between the direct-current voltage input ends, each current limiting unit is used for limiting the current flowing through each switch switching unit when the switch switching unit acts, damage probability of the switch switching unit is reduced, switching time of the switch switching unit is reduced, and charging efficiency of the direct-current voltage output switching circuit is improved.

Description

Direct-current voltage output switching circuit, switching method and charging pile power module

Technical Field

The embodiment of the invention relates to the technical field of charging, in particular to a direct-current voltage output switching circuit, a switching method and a charging pile power module.

Background

The existing charging pile power module is provided with two paths of direct current-direct current conversion circuits, the two paths of direct current-direct current conversion circuits are connected with a battery to be charged through an output series/parallel connection switching circuit, and the output series/parallel connection switching circuit can switch the series connection or the parallel connection of the output ends of the two paths of direct current-direct current conversion circuits according to the type of an electric vehicle, so that the charging pile power module can be used for adjusting the charging voltage required by the battery to be charged. The existing output series/parallel switching circuit generally adopts a switch of an alternating current relay to switch the series connection or the parallel connection of the output ends of two paths of direct current-direct current conversion circuits, and when the state of the alternating current relay switch is switched, the phenomenon that the switch is damaged due to overlarge current is easy to occur when the switch is switched. Or the stored electric energy is discharged before the switch is switched, so that the current during the switch switching is reduced, the switching time of the switch is prolonged, meanwhile, the electric energy waste is caused, and the charging efficiency is reduced.

Disclosure of Invention

The invention provides a direct-current voltage output switching circuit, a switching method and a charging pile power module, which are used for reducing switching current on the basis of not increasing switching time, improving switching reliability and improving charging efficiency.

In a first aspect, an embodiment of the present invention provides a dc voltage output switching circuit, configured to switch an output voltage of a charging pile power module, where the dc voltage output switching circuit includes at least two sets of dc voltage input terminals, at least two input storage units, a dc voltage output terminal, an output storage unit, a switch switching unit, and a current limiting unit;

Each input storage unit is connected in parallel between two poles of a direct-current voltage input end, each output storage unit is connected in parallel between two poles of a direct-current voltage output end, each switch switching unit is connected with the direct-current voltage input end, each current limiting unit is connected in series between the direct-current voltage input end and the direct-current voltage output end, each switch switching unit is used for switching the connection state between the direct-current voltage input ends, and each current limiting unit is used for limiting the current flowing through each switch switching unit when the switch switching unit acts.

Optionally, the current limiting unit includes a first switch and a current limiting module;

The first switch is connected in series between the direct-current voltage input end and the direct-current voltage output end, and the current limiting module is connected in parallel with the first switch; the current limiting module is used for limiting the current flowing through the switch switching unit when the switch switching unit acts, and the first switch module is used for acting when the output voltage of the direct-current voltage output end is a first threshold voltage.

Optionally, the current limiting module comprises an uncontrolled rectifier tube and a current limiting resistor;

The positive electrode of the uncontrolled rectifying tube is connected with the positive electrode of the direct-current voltage input end, and the negative electrode of the uncontrolled rectifying tube is connected with the positive electrode of the direct-current voltage output end through the current limiting resistor.

Optionally, the current limiting module comprises a second switch and a current limiting resistor;

The first end of the second switch is connected with the positive electrode of the direct-current voltage input end, and the second end of the second switch is connected with the positive electrode of the direct-current voltage output end through the current limiting resistor.

Optionally, the direct-current voltage output switching circuit further comprises a control unit;

The control unit is used for forming a first control signal according to a switching instruction or according to output voltage provided by the direct-current voltage output end and at least two input voltages provided by the direct-current voltage input end, and the first switch is used for acting according to the first control signal.

Optionally, the direct-current voltage output switching circuit further comprises a control unit and an overcurrent protection unit;

The control unit is used for forming a first control signal according to a switching instruction or according to the output voltage provided by the direct-current voltage output end and at least two input voltages provided by the direct-current voltage input end; the overcurrent protection unit is used for forming a first switch control signal according to the current before the storage unit is output, the preset current and the first control signal, and the first switch is used for acting according to the first switch control signal.

Optionally, the overcurrent protection unit includes a comparison subunit and an and logic subunit;

The comparison subunit is used for forming a comparison signal according to the current before the output storage unit and the preset current, the AND logic subunit is respectively connected with the comparison subunit and the control unit, and the AND logic subunit is used for forming a first switch control signal according to the comparison signal and the first control signal.

The control unit is used for forming a second control signal according to a switching instruction or according to the output voltage provided by the direct-current voltage output end and at least two input voltages provided by the direct-current voltage input end, and the second switch is used for acting according to the second control signal.

Optionally, the switch switching unit includes a third switch, a fourth switch and a fifth switch;

The third switch is connected in series between the positive electrode of the i-th group of direct-current voltage input ends and the positive electrode of the i+1-th group of direct-current voltage input ends, the fourth switch is connected in series between the negative electrode of the i-th group of direct-current voltage input ends and the negative electrode of the i+1-th group of direct-current voltage input ends, and the fifth switch is connected in series between the negative electrode of the i-th group of direct-current voltage input ends and the positive electrode of the i+1-th group of direct-current voltage input ends; wherein i is an integer greater than or equal to 1 and less than j, j being the number of groups of the DC voltage input terminals.

Optionally, the control unit is further configured to form a third control signal, a fourth control signal and a fifth control signal according to a switching instruction, where the third switch is configured to operate according to the third control signal, the fourth switch is configured to operate according to the fourth control signal, and the fifth switch is configured to operate according to the fifth control signal; in the same period, the fifth control signal has a delay with respect to the second control signal, or the third control signal and the fourth control signal have a delay with respect to the second control signal.

Optionally, the input storage unit includes an input capacitor, and the output storage unit includes an output capacitor;

each input capacitor is connected in parallel between the positive electrode and the negative electrode of one direct-current voltage input end, and each output capacitor is connected in parallel between the positive electrode and the negative electrode of the direct-current voltage output end.

In a second aspect, an embodiment of the present invention further provides a method for switching a dc voltage output, which is implemented by using the dc voltage output switching circuit provided in the first aspect; comprising the following steps:

when the switch switching unit switches the connection state between the direct-current voltage input ends, the current limiting unit limits the current flowing through the switch switching unit.

Optionally, the current limiting unit includes a first switch and a current limiting module; when the switch switching unit switches the connection state between the direct-current voltage input ends, the current limiting unit limits the current flowing through the switch switching unit, and the switch switching unit comprises:

When the switch switching unit switches the connection state between the direct-current voltage input ends, the current limiting module limits the current flowing through the switch switching unit;

And when the output voltage of the direct-current voltage output end is the first threshold voltage, the first switch acts.

Optionally, the current limiting module comprises a second switch and a current limiting resistor; when the switch switching unit switches the connection state between the direct-current voltage input ends, the current limiting module limits the current flowing through the switch switching unit, and the current limiting module comprises:

when the switch switching unit switches the connection state between the direct-current voltage input ends, the second switch is closed, and the current limiting resistor limits the current flowing through the switch switching unit.

Optionally, the switch switching unit includes a third switch, a fourth switch and a fifth switch; when the switch switching unit switches the connection state between the direct-current voltage input ends, the second switch is closed, the current limiting resistor limits the current flowing through the switch switching unit, and the switch switching unit comprises:

when the switch switching unit switches the connection state between the direct-current voltage input ends from parallel connection to series connection,

In a first stage, the first switch, the third switch and the fourth switch are switched from closed to open, and the second switch is switched from open to closed;

In the second stage, the fifth switch is switched from off to on;

when the switch switching unit switches the connection state between the direct-current voltage input ends from serial connection to parallel connection,

In a first stage, the first switch and the fifth switch are switched from closed to open, and the second switch is switched from open to closed;

in a second phase, the third switch and the fourth switch are switched from off to on.

Optionally, the switching method of the direct current voltage output further includes:

and when the current before the memory cell is output is greater than the preset current, the first switch acts.

In a third aspect, an embodiment of the present invention further provides a charging pile power module, including the dc voltage output switching circuit provided in the first aspect.

According to the technical scheme provided by the embodiment of the invention, the current limiting unit is arranged on the conduction loop of the switch switching unit, so that the current flowing through the switch switching unit is limited by the current limiting unit, and therefore, the large current flowing through the switch switching unit when the switch switching unit switches the connection state between the direct-current voltage input ends can be avoided, and the damage probability of the switch switching unit is reduced. Meanwhile, the input storage unit and the output storage unit can be prevented from discharging when the switch switching unit switches the connection state between the direct-current voltage input ends, the switching time when the switch switching unit switches the connection state between the direct-current voltage input ends is reduced, the electric energy waste is avoided, and the charging efficiency of the direct-current voltage output switching circuit is improved.

Drawings

Fig. 1 is a schematic diagram of a dc voltage output switching circuit according to the prior art;

fig. 2 is a schematic structural diagram of a dc voltage output switching circuit according to an embodiment of the present invention;

fig. 3 is a schematic diagram of another dc voltage output switching circuit according to an embodiment of the present invention;

Fig. 4 is a schematic structural diagram of another dc voltage output switching circuit according to an embodiment of the present invention;

fig. 5 is a schematic diagram of another dc voltage output switching circuit according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of another dc voltage output switching circuit according to an embodiment of the present invention;

Fig. 7 is a schematic structural diagram of another dc voltage output switching circuit according to an embodiment of the present invention;

fig. 8 is a schematic diagram of another dc voltage output switching circuit according to an embodiment of the present invention;

FIG. 9 is a flow chart of a method for switching DC voltage output according to an embodiment of the present invention;

fig. 10 is a schematic structural diagram of a charging pile power module according to an embodiment of the present invention.

Detailed Description

The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.

Fig. 1 is a schematic diagram of a dc voltage output switching circuit according to the prior art. As shown in fig. 1, the dc voltage output switching circuit includes two sets of voltage input terminals, voltage output terminals, a first storage capacitor C1, a second storage capacitor C2, a third storage capacitor C3, a first relay switch S1, a second relay switch S2, and a third relay switch S3. The first storage capacitor C1 is connected in parallel between the positive electrode Vo < 1+ > and the negative electrode Vo < 1 > -of the first group of voltage input terminals, the second storage capacitor C2 is connected in parallel between the positive electrode Vo < 2+ > and the negative electrode Vo < 2 > -of the second group of voltage input terminals, the third storage capacitor C3 is connected in parallel between the positive electrode Vo < 1+ > and the negative electrode Vo < - >, the first relay switch S1 is connected in series between the positive electrode Vo < 1+ > of the first group of voltage input terminals and the positive electrode Vo < 2+ >, the second relay switch S2 is connected in series between the negative electrode Vo < 1 > -of the first group of voltage input terminals and the negative electrode Vo < 2 > -of the second group of voltage input terminals, and the third relay switch S3 is connected in series between the negative electrode Vo < 1 > -of the first group of voltage input terminals and the positive electrode Vo < 2 >. When the direct-current voltage output switching circuit works and needs to output low voltage for charging, the first relay switch S1 and the second relay switch S2 can be controlled to be closed, the third relay switch S3 is opened, at the moment, two groups of voltage input ends are connected in parallel, and then the output voltage of the voltage output end is equal to the input voltage of each group of voltage input ends, namely, vo=vo1=vo2. Wherein Vo is the output voltage, vo1 is the first input voltage provided by the first set of voltage inputs, and Vo2 is the second input voltage provided by the second set of voltage inputs. When the high voltage is required to be output for charging, the first relay switch S1 and the second relay switch S2 can be controlled to be opened, the third relay switch S3 is closed, at the moment, the two groups of voltage input ends are connected in series, and then the output voltage of the voltage output end is equal to the sum of the input voltages of each group of voltage input ends, namely, vo=vo1+vo2.

In the charging process, when the output voltage of the direct-current voltage output switching circuit needs to be charged across the low voltage and the high voltage, the states of the first relay switch S1, the second relay switch S2, and the third relay switch S3 need to be switched. Illustratively, when the output voltage of the direct-current voltage output switching circuit is switched from low voltage to high voltage, the first relay switch S1 and the second relay switch S2 are switched from closed to open, and the third relay switch S3 is switched from open to closed. In the switching process, when the first relay switch S1 and the second relay switch S2 are switched from closed to open and then the third relay switch S3 is immediately closed, the voltages on the first storage capacitor C1, the second storage capacitor C2 and the third storage capacitor C3 will not be suddenly changed, at this time, the conduction voltage drop born by the third relay switch S3 is the difference between the sum vo1+vo2 of the input voltages of each group of voltage input ends and the input voltage Vo1 or Vo2 of each group of voltage input ends, and the conduction resistance of the third relay switch S3 is very small, so that the current flowing through the third relay switch S3 is very large, and the third relay switch S3 is easy to be damaged. Or in order to avoid the damage of the third relay switch S3, after the first relay switch S1 and the second relay switch S2 are switched from closed to open, the first storage capacitor C1, the second storage capacitor C2 and the third storage capacitor C3 may be discharged first, and then the third relay switch S3 is closed, so that the safe and reliable closing of the third relay switch S3 may be ensured. However, the discharging process of the first storage capacitor C1, the second storage capacitor C2 and the third storage capacitor C3 requires time, and after the third relay switch S3 is closed, the first storage capacitor C1, the second storage capacitor C2 and the third storage capacitor C3 need to be recharged, which results in long switching time in the switching process, and in serious cases, the vehicle battery management system reports a fault, and meanwhile, the energy on the first storage capacitor C1, the second storage capacitor C2 and the third storage capacitor C3 does not flow into the battery to be charged, which results in energy waste and reduces the charging efficiency in the charging process. When the output voltage of the direct-current voltage output switching circuit is switched from high voltage to low voltage, the third relay switch S3 is switched from closed to open, and the first relay switch S1 and the second relay switch S2 are switched from open to closed. The above-mentioned problems also exist during the handover process.

Aiming at the technical problems, the embodiment of the invention provides a direct-current voltage output switching circuit. Fig. 2 is a schematic structural diagram of a dc voltage output switching circuit according to an embodiment of the present invention. As shown IN fig. 2, the dc voltage output switching circuit is configured to switch the output voltage of the charging pile power module, and includes at least two sets of dc voltage input terminals IN, at least two input storage units 110, a dc voltage output terminal OUT, an output storage unit 120, a switch switching unit 130, and a current limiting unit 140; each of the input memory units 110 is connected IN parallel between two poles of a dc voltage input terminal IN, the output memory unit 120 is connected IN parallel between two poles of a dc voltage output terminal OUT, the switching unit 130 is connected with the dc voltage input terminal IN, the current limiting unit 140 is connected IN series between the dc voltage input terminal IN and the dc voltage output terminal OUT, the switching unit 130 is used for switching the connection state between the dc voltage input terminals IN, and the current limiting unit 140 is used for limiting the current flowing through the switching unit 130 when the switching unit 130 acts.

Specifically, fig. 2 exemplarily shows that the dc voltage output switching circuit includes two sets of dc voltage input terminals IN, which are a first dc voltage input terminal IN1 and a second dc voltage input terminal IN2, respectively, and each set of dc voltage input terminals IN includes a positive electrode and a negative electrode. Two input memory cells 110 are correspondingly arranged, and each input memory cell 110 is connected IN parallel between the positive electrode and the negative electrode of one direct-current voltage input terminal IN. Each of the input memory cells 110 may store an input voltage provided by a corresponding connected dc voltage input terminal IN. The dc voltage output terminal OUT also includes a positive electrode and a negative electrode, and the output storage unit 120 is connected in parallel between the positive electrode and the negative electrode of the dc voltage output terminal OUT, and can store the output voltage provided by the dc voltage output terminal OUT. The switching unit 130 is connected to the dc voltage input terminal IN, and can switch the connection state between the dc voltage input terminals IN series or parallel, so that the voltage value provided to the dc voltage output terminal OUT can be controlled by the switching unit 130. When the connection state between the dc voltage input terminals IN is switched IN series by the switching unit 130, the voltage value provided to the dc voltage output terminal OUT by the dc voltage input terminal IN is equal to the sum of the voltages provided by each of the dc voltage input terminals IN, and is a high voltage. Illustratively, when the input voltage provided by the two sets of dc voltage input terminals IN illustrated IN fig. 2 is Vin, the voltage value Vout of the dc voltage output terminal OUT is equal to the sum of the two input voltages Vin, i.e., vout=vin+vin. When the connection state between the dc voltage input terminals IN is switched IN parallel by the switching unit 130, the voltage value provided by the dc voltage input terminal IN to the dc voltage output terminal OUT is equal to the voltage provided by each dc voltage input terminal IN, and is a low voltage. Illustratively, the two sets of dc voltage inputs IN exemplarily shown IN fig. 2 provide an input voltage Vin, and the voltage value Vout of the dc voltage output OUT is equal to the input voltage Vin, i.e., vout=vin. When the switch switching unit 130 switches the connection state between the dc voltage input terminals IN, the power on the input storage unit 110 and the output storage unit 120 will not be suddenly changed, so that the conduction voltage drop born by the switch switching unit 130 is the difference between the high voltage and the low voltage. The on-resistance of the switching unit 130 is relatively small, and the current limiting unit 140 is arranged on the on-loop of the switching unit 130, so that the current limiting unit 140 limits the current flowing through the switching unit 130, thereby avoiding the large current flowing through the switching unit 130 when the switching unit 130 switches the connection state between the direct-current voltage input ends IN, and reducing the damage probability of the switching unit 130. Meanwhile, the input storage unit 110 and the output storage unit 120 can be prevented from discharging when the switch switching unit 130 switches the connection state between the direct-current voltage input ends IN, the switching time when the switch switching unit 130 switches the connection state between the direct-current voltage input ends IN is reduced, the electric energy waste is avoided, and the charging efficiency of the direct-current voltage output switching circuit is improved.

Fig. 3 is a schematic diagram of another dc voltage output switching circuit according to an embodiment of the present invention. As shown in fig. 3, the current limiting unit 140 includes a first switch K1 and a current limiting module 141; the first switch K1 is connected IN series between the dc voltage input terminal IN and the dc voltage output terminal OUT, and the current limiting module 141 is connected IN parallel with the first switch K1; the current limiting module 141 is configured to limit a current flowing through the switching unit 130 when the switching unit 130 is operated, and the first switch K1 module is configured to operate when the output voltage of the dc voltage output terminal OUT is a first threshold voltage.

Specifically, when the switching unit 130 switches the connection state between the dc voltage input terminals IN, the current limiting module 141 may limit the current flowing through the switching unit 130, so that a large current flowing through the switching unit 130 when the switching unit 130 switches the connection state between the dc voltage input terminals IN may be avoided, and the damage probability of the switching unit 130 is reduced. After the connection state between the dc voltage input ends IN is successfully switched by the switch switching unit 130, the voltage input to the storage unit 110 is equal to the voltage output to the storage unit 120, the output voltage of the dc voltage output end OUT is converted into the first threshold voltage, and at this time, the first switch K1 can be closed, so that the first switch K1 bypasses the current limiting module 141, the voltage provided by the dc voltage input end IN is transmitted to the dc voltage output end OUT through the first switch K1, the current limiting module 141 is prevented from consuming electric energy, and the charging efficiency of the dc voltage output switching circuit is ensured. The first threshold voltage is a voltage value of the dc voltage output terminal OUT after the switching unit 130 switches the connection state between the dc voltage input terminals IN. Illustratively, when the switching unit 130 switches the connection state between the dc voltage input terminals IN from serial to parallel, the voltage value of the dc voltage output terminal OUT is converted from high voltage to low voltage, and the first threshold voltage is low voltage at this time, the first switch K1 operates when the voltage of the dc voltage output terminal OUT is low voltage. When the switch switching unit 130 switches the connection state between the dc voltage input terminals IN from parallel to series, the voltage value of the dc voltage output terminal OUT is changed from low voltage to high voltage, and the first threshold voltage is the high voltage at this time, the first switch K1 operates when the voltage of the dc voltage output terminal OUT is the high voltage.

Fig. 4 is a schematic diagram of another dc voltage output switching circuit according to an embodiment of the present invention. As shown in fig. 4, the current limiting module 141 includes an uncontrolled rectifier D1 and a current limiting resistor R1; the positive pole of the uncontrolled rectifier tube D1 is connected with the positive pole of the direct current voltage input end IN, and the negative pole of the uncontrolled rectifier tube D1 is connected with the positive pole of the direct current voltage output end OUT through a current limiting resistor R1.

Specifically, the uncontrolled rectifier D1 has a unidirectional conduction effect. When the switch switching unit 130 switches the connection state between the dc voltage input terminals IN, the power on the input storage unit 110 and the output storage unit 120 will not be suddenly changed, so that the conduction voltage drop born by the switch switching unit 130 is the difference between the high voltage and the low voltage, and a large current is generated on the conduction loop of the switch switching unit 130. Meanwhile, the first switch K1 is turned off, the input voltage provided by the dc voltage input terminal IN is provided to the dc voltage output terminal OUT through the uncontrolled rectifier D1 and the current limiting resistor R1, so as to charge the output storage unit 120, and the current limiting resistor R1 can limit the large current on the conduction loop, so that the current on the conduction loop of the switch switching unit 130 is reduced. When the voltage of the output storage unit 120 is equal to the voltage of the input storage unit 110, the currents on the uncontrolled rectifier tube D1 and the current limiting resistor R1 are zero, at this time, the voltage of the direct-current voltage output end OUT is the first threshold voltage, and the first switch K1 is controlled to act, so that the first switch K1 bypasses the uncontrolled rectifier tube D1 and the current limiting resistor R1, the voltage provided by the direct-current voltage input end IN is transmitted to the direct-current voltage output end OUT through the first switch K1, the current limiting module 141 is prevented from consuming electric energy, and the charging efficiency of the direct-current voltage output switching circuit is ensured.

Illustratively, the dc voltage output switching circuit shown IN fig. 4 includes two sets of dc voltage input terminals IN, respectively, the first dc voltage input terminal IN1 and the second dc voltage input terminal IN2, which provide equal input voltages Vin. When the switch switching unit 130 controls the two dc voltage input terminals IN to be IN the parallel state, the first switch K1 is turned on, and the voltage of the dc voltage input terminal IN is provided to the dc voltage output terminal OUT through the first switch K1, where the output voltage Vout of the dc voltage output terminal OUT is equal to the input voltage Vin, i.e. vout=vin. When the switch switching unit 130 controls the two dc voltage input terminals IN to be switched from parallel to series, the voltage of the output storage unit 120 will not be suddenly changed, the voltage stored IN the input storage unit 110 is greater than the voltage of the output storage unit 120, at this time, the conduction voltage drop born by the switch switching unit 130 is the difference between the high voltage and the low voltage, the first switch K1 is disconnected, the current flowing through the switch switching unit 130 is controlled by the uncontrolled rectifier tube D1 and the current limiting resistor R1, so that the large current flowing through the switch switching unit 130 is avoided, and the damage probability of the switch switching unit 130 is reduced. When the voltage of the dc voltage output terminal OUT reaches the first threshold voltage, the voltage stored IN the input storage unit 110 is equal to the voltage of the output storage unit 120, the output voltage of the dc voltage output terminal OUT is converted into the first threshold voltage, at this time, the first switch K1 can be closed, so that the first switch K1 bypasses the current limiting module 141, the voltage provided by the dc voltage input terminal IN is transmitted to the dc voltage output terminal OUT through the first switch K1, the parallel conversion of the dc voltage input terminal IN into serial switching is completed, the loss of electric energy by the current limiting module 141 is avoided, and the charging efficiency of the dc voltage output switching circuit is ensured.

Fig. 5 is a schematic diagram of another dc voltage output switching circuit according to an embodiment of the present invention. As shown in fig. 5, the current limiting module 141 includes a second switch K2 and a current limiting resistor R1; the first end of the second switch K2 is connected with the positive electrode of the direct-current voltage input end IN, and the second end of the second switch K2 is connected with the positive electrode of the direct-current voltage output end OUT through a current limiting resistor R1.

Specifically, the second switch K2 has a bidirectional conduction function, and when the switch switching unit 130 switches the connection state between the dc voltage input terminals IN, the current formed by the voltage difference between the input storage unit 110 and the output storage unit 120 can pass through the branch where the second switch K2 and the current limiting resistor R1 are located, so that the current limiting module 141 can limit the bidirectional current. Illustratively, the dc voltage output switching circuit shown IN fig. 5 includes two sets of dc voltage input terminals IN, respectively, the first dc voltage input terminal IN1 and the second dc voltage input terminal IN2, which provide equal input voltages Vin. When the switch switching unit 130 controls the two dc voltage input terminals IN to be IN the parallel state, the first switch K1 is closed, the second switch K2 is opened, and the voltage of the dc voltage input terminal IN is provided to the dc voltage output terminal OUT through the first switch K1, and at this time, the output voltage Vout of the dc voltage output terminal OUT is equal to the input voltage Vin, i.e., vout=vin. When the switch switching unit 130 controls the two dc voltage input terminals IN to be switched from parallel to series, the voltage of the output storage unit 120 will not be suddenly changed, the voltage stored IN the input storage unit 110 is greater than the voltage of the output storage unit 120, at this time, the conduction voltage drop born by the switch switching unit 130 is the difference between the high voltage and the low voltage, the first switch K1 is opened, the second switch K2 is closed, the current flowing through the switch switching unit 130 is controlled by the second switch K2 and the current limiting resistor R1, so that the large current flowing through the switch switching unit 130 is avoided, and the damage probability of the switch switching unit 130 is reduced. When the voltage of the dc voltage output terminal OUT reaches the first threshold voltage, the first threshold voltage is a high voltage, that is, vout=vin+vin. The voltage stored IN the input storage unit 110 is equal to the voltage stored IN the output storage unit 120, the output voltage of the dc voltage output terminal OUT is converted into a first threshold voltage, and at this time, the first switch K1 can be turned on, so that the first switch K1 bypasses the current limiting module 141, the voltage provided by the dc voltage input terminal IN is transmitted to the dc voltage output terminal OUT through the first switch K1, and the switching from parallel conversion of the dc voltage input terminal IN into serial connection is completed.

When the connection state of the dc voltage input terminals IN is converted from serial to parallel, the first switch K1 is closed and the second switch K2 is opened when the switch switching unit 130 controls the two dc voltage input terminals IN to be IN serial, and the voltage of the dc voltage input terminal IN is provided to the dc voltage output terminal OUT through the first switch K1, at this time, the output voltage Vout of the dc voltage output terminal OUT is equal to the sum of the input voltages Vin, i.e., vout=vin+vin. When the connection state of the dc voltage input terminal IN is changed from series connection to parallel connection, the voltage of the output storage unit 120 will not be suddenly changed, the voltage stored IN the output storage unit 110 is greater than the voltage of the input storage unit 120, at this time, the conduction voltage drop born by the switch switching unit 130 is the difference between the high voltage and the low voltage, the first switch K1 is opened, the second switch K2 is closed, the current flowing through the switch switching unit 130 is controlled by the second switch K2 and the current limiting resistor R1, so that the large current flowing through the switch switching unit 130 is avoided, and the damage probability of the switch switching unit 130 is reduced. When the voltage of the dc voltage output terminal OUT reaches the first threshold voltage, the first threshold voltage is a low voltage, that is, vout=vin, the voltage stored IN the input storage unit 110 is equal to the voltage of the output storage unit 120, the output voltage of the dc voltage output terminal OUT is converted into the first threshold voltage, and at this time, the first switch K1 may be turned on, so that the first switch K1 bypasses the current limiting module 141, and the voltage provided by the dc voltage input terminal IN is transmitted to the dc voltage output terminal OUT through the first switch K1.

Fig. 6 is a schematic diagram of another dc voltage output switching circuit according to an embodiment of the present invention. As shown in fig. 6, the dc voltage output switching circuit further includes a control unit 150; the control unit 150 is configured to form a first control signal ctrl1 according to a switching instruction or according to an output voltage provided by the dc voltage output terminal OUT and at least two input voltages provided by the dc voltage input terminal IN, and the first switch K1 is configured to operate according to the first control signal ctrl 1.

Specifically, when the switch switching unit 130 is used to switch the connection state between the dc voltage input terminals IN, the control unit 150 may form the first control signal ctrl1 according to the switching instruction, and the first switch K1 is turned off according to the first control signal ctrl 1. IN addition, the control unit 150 may receive the output voltage provided from the dc voltage output terminal OUT and the input voltage provided from the dc voltage input terminal IN. The control unit 150 may collect the output voltage provided from the dc voltage output terminal OUT and the input voltage provided from the dc voltage input terminal IN through a sampling circuit, for example. When the switch switching unit 130 switches the connection state between the dc voltage input terminals IN, the control unit 150 may form the first control signal ctrl1 when the output voltage is equal to the first threshold voltage, and the first switch K1 is closed according to the first control signal ctrl 1. The dc voltage output switching circuit includes two dc voltage input terminals IN, which are a first dc voltage input terminal IN1 and a second dc voltage input terminal IN2, respectively, and provide an equal input voltage Vin. When the switch switching unit 130 controls the two dc voltage input terminals IN to switch from parallel to series, the first threshold voltage reached by the output voltage Vout of the dc voltage output terminal OUT is a high voltage, that is, vout=vin+vin. The control unit 150 obtains the output voltage Vout of the dc voltage output terminal OUT IN real time, and compares the output voltage Vout with the two input voltages Vin provided by the two sets of dc voltage input terminals IN. When the output voltage Vout of the dc voltage output terminal OUT is equal to the sum of the two input voltages Vin provided by the two sets of dc voltage input terminals IN, a first control signal ctrl1 is formed, and the first switch K1 is turned on according to the first control signal ctrl 1. When the switch switching unit 130 controls the two dc voltage input terminals IN to switch from serial to parallel, the first threshold voltage reached by the output voltage Vout of the dc voltage output terminal OUT is low, that is, vout=vin. The control unit 150 obtains the output voltage Vout of the dc voltage output terminal OUT IN real time, and compares the output voltage Vout with the two input voltages Vin provided by the two sets of dc voltage input terminals IN. When the output voltage Vout of the dc voltage output terminal OUT is equal to the two input voltages Vin provided by the two sets of dc voltage input terminals IN, a first control signal ctrl1 is formed, and the first switch K1 is closed according to the first control signal ctrl 1. For example, the first switch K1 may be closed when the first control signal ctrl1 is set to a high level.

It should be noted that fig. 6 only exemplarily illustrates that the first switch K1 operates according to the first control signal ctrl1 when the current limiting module 141 includes the second switch K2 and the current limiting resistor R1. In other embodiments, when the current limiting module 141 includes the uncontrolled rectifier D1 and the current limiting resistor R1, the first switch K1 can also act according to the first control signal ctrl1, which is not described herein again.

Fig. 7 is a schematic diagram of another dc voltage output switching circuit according to an embodiment of the present invention. As shown in fig. 7, the dc voltage output switching circuit further includes a control unit 150 and an overcurrent protection unit 160; the control unit 150 is configured to form a first control signal ctrl1 according to a switching instruction or according to an output voltage provided by the dc voltage output terminal OUT and at least two input voltages provided by the dc voltage input terminal IN; the over-current protection unit 160 is configured to form a first switch control signal ctrl11 according to the output pre-memory cell current isec, the preset current ipro, and the first control signal ctrl1, and the first switch K1 is configured to operate according to the first switch control signal ctrl 11.

Specifically, when the switch switching unit 130 is used to switch the connection state between the dc voltage input terminals IN, the control unit 150 may form the first control signal ctrl1 according to the switching instruction, the first control signal ctrl1 may be at a low level, and the first switch K1 may be turned off according to the first control signal ctrl 1. When the switch switching unit 130 switches the connection state between the dc voltage input terminals IN, the control unit 150 may form the first control signal ctrl1 when the output voltage provided by the dc voltage output terminal OUT is equal to the first threshold voltage, and the first control signal ctrl1 may control the first switch K1 to be closed, for example, the first control signal ctrl1 may be at a high level. The output cell front current isec is a current before the output cell 120, and as shown IN fig. 7, the output cell front current isec is a current between the dc voltage input terminal IN and the dc voltage output terminal OUT. The preset current ipro is a preset current. The preset current ipro may be, for example, a current short-circuit protection threshold current. The over-current protection unit 160 may determine whether the dc voltage output switching circuit is in a normal operating state according to the pre-output current isec and the preset current ipro, and then form a first switch control signal ctrl11 according to the first control signal ctrl1 to control the first switch K1. When the dc voltage output switching circuit works normally, the output memory cell front current isec is smaller than the preset current ipro, the over-current protection unit 160 forms a first switch control signal ctrl11 according to the first control signal ctrl1, and the first switch K1 acts according to the first switch control signal ctrl 11. When the dc voltage output switching circuit outputs a short circuit, the pre-memory cell current isec is greater than the preset current ipro, the over-current protection unit 160 forms a first switch control signal ctrl11 according to the pre-memory cell current isec being greater than the preset current ipro, and the first switch K1 is turned off according to the first switch control signal ctrl11, so that the short circuit protection of the dc voltage output switching circuit can be realized.

With continued reference to fig. 7, the over-current protection unit includes a comparison subunit 161 and an and logic subunit 162; the comparing subunit 161 is configured to form a comparison signal comp according to the output pre-memory cell current isec and the preset current ipro, the and logic subunit 162 is respectively connected to the comparing subunit 161 and the control unit 150, and the and logic subunit 162 is configured to form a first switch control signal ctrl11 according to the comparison signal comp and the first control signal ctrl 1.

Specifically, when the switching unit 130 switches the connection state between the dc voltage input terminals IN, the control unit 150 may form the first control signal ctrl1 when the output voltage provided by the dc voltage output terminal OUT is equal to the first threshold voltage, the first control signal ctrl1 may control the first switch K1 to be closed, for example, the first control signal ctrl1 may be at a high level. The output cell front current isec is a current before the output cell 120, and as shown IN fig. 7, the output cell front current isec is a current between the dc voltage input terminal IN and the dc voltage output terminal OUT. The preset current ipro is a preset current. The preset current ipro may be, for example, a current short-circuit protection threshold current. When the dc voltage output switching circuit works normally, the output memory cell pre-current isec is smaller than the preset current ipro, and the comparing unit 161 forms a comparing signal comp according to the output memory cell pre-current isec and the preset current ipro, where the comparing signal comp may control the first switch K1 to be closed, for example, the comparing signal comp may be at a high level. The and logic unit 162 forms a first switch control signal ctrl11 according to the comparison signal comp and the first control signal ctrl1, and at this time, the first switch K1 is turned on according to the first switch control signal ctrl 11. That is, when the dc voltage output switching circuit works normally, the state of the first switch control signal ctrl11 is the same as the state of the first control signal ctrl1, and at this time, the first switch K1 is equivalent to operate according to the first control signal ctrl 1. When the dc voltage output switching circuit outputs a short circuit, the output memory cell pre-current isec is greater than the preset current ipro, and the comparison unit 161 forms a comparison signal comp according to the output memory cell pre-current isec and the preset current ipro, the comparison signal comp may control the first switch K1 to be turned off, for example, the comparison signal comp may be at a low level. The and logic unit 162 forms the first switching control signal ctrl11 according to the comparison signal comp and the first control signal ctrl1, and at this time, the state of the first switching control signal ctrl11 is the same as the state of the comparison signal comp, and the first switch K1 is turned off according to the first switching control signal ctrl11, so that the short-circuit protection of the dc voltage output switching circuit can be realized.

In addition, when the current limiting module 141 includes the uncontrolled rectifier D1 and the current limiting resistor R1, or when the current limiting module 141 includes the second switch K2 and the current limiting resistor R1, and the second switch K2 is closed after the first switch K1 is opened, the short-circuit current can be suppressed by the current limiting resistor R1, so as to realize the short-circuit protection of the switch switching unit 130. Meanwhile, the comparison signal comp may be fed back to the control unit 150, and when the dc voltage output switching circuit outputs a short circuit, the control unit 150 controls the dc voltage input terminal IN to stop providing the input voltage according to the comparison signal comp, thereby further protecting the dc voltage output switching circuit.

On the basis of the above technical solutions, with continued reference to fig. 7, when the current limiting module 141 in the current limiting unit 140 includes the second switch K2 and the current limiting resistor R1, the dc voltage output switching circuit further includes the control unit 150; the control unit 150 is configured to form a second control signal ctrl2 according to the switching command or according to the output voltage provided by the dc voltage output terminal OUT and at least two input voltages provided by the dc voltage input terminal IN, and the second switch K2 is configured to operate according to the second control signal ctrl 2.

Specifically, the control unit 150 may also control the state of the switch changeover unit 130. When the switch switching unit 130 is used for switching the connection state between the dc voltage input ends IN, the control unit 150 forms the second control signal ctrl2 according to the switching instruction, the second switch K2 can control the second switch K2 to be closed according to the second control signal ctrl2, and then the switch switching unit 130 is controlled to switch the connection state between the dc voltage input ends IN according to the switching instruction, so that when the switch switching unit 130 switches the connection state between the dc voltage input ends IN, the current passes through the branch where the second switch K2 is located, so that the current limiting resistor R1 limits the current, thereby avoiding the large current flowing through the switch switching unit 130 and reducing the damage probability of the switch switching unit 130. After the switching unit 130 is used for switching the connection state between the dc voltage input ends IN, the control unit 150 forms a first control signal ctrl1 when the output voltage is equal to the first threshold voltage, the first switch K1 is closed according to the first control signal ctrl1, then the control unit 150 forms a second control signal ctrl2 according to the first control signal ctrl1, and the second switch K2 is opened according to the second control signal ctrl2, so that the branch where the second switch K2 and the current limiting resistor R1 are located can be bypassed on the basis of continuous operation of the dc voltage switching current, the loss of electric energy by the current limiting module 141 is avoided, and the charging efficiency of the dc voltage output switching circuit is ensured.

Fig. 8 is a schematic diagram of another dc voltage output switching circuit according to an embodiment of the present invention. As shown in fig. 8, the switch switching unit 130 includes a third switch K3, a fourth switch K4, and a fifth switch K5; the third switch K3 is connected IN series between the positive electrode of the i-th group direct-current voltage input end IN and the positive electrode of the i+1-th group direct-current voltage input end IN, the fourth switch K4 is connected IN series between the negative electrode of the i-th group direct-current voltage input end IN and the negative electrode of the i+1-th group direct-current voltage input end IN, and the fifth switch K5 is connected IN series between the negative electrode of the i-th group direct-current voltage input end IN and the positive electrode of the i+1-th group direct-current voltage input end IN; wherein i is an integer greater than or equal to 1 and less than j, j being the number of groups of the DC voltage input terminals IN.

Specifically, fig. 8 exemplarily shows that the dc voltage output switching circuit includes two sets of dc voltage input terminals IN, namely, a first dc voltage input terminal IN1 and a second dc voltage input terminal IN2, a third switch K3 is connected IN series between the positive electrode of the first dc voltage input terminal IN1 and the positive electrode of the second dc voltage input terminal IN2, a fourth switch K4 is connected IN series between the negative electrode of the first dc voltage input terminal IN1 and the negative electrode of the second dc voltage input terminal IN2, and a fifth switch K5 is connected IN series between the negative electrode of the first dc voltage input terminal IN1 and the positive electrode of the second dc voltage input terminal IN 2. When the switch switching unit 130 controls the two dc voltage input terminals IN to be connected IN parallel, the third switch K3 and the fourth switch K4 are closed, and the fifth switch K5 is opened. When the switch switching unit 130 controls the two dc voltage inputs IN to switch from parallel to series, the third switch K3 and the fourth switch K4 switch from closed to open, and the fifth switch K5 switches from open to closed. Before the fifth switch K5 is turned on, the first switch K1 is turned off, and the current passes through the branch where the current limiting module 141 is located, so that the current limiting module 141 can avoid the fifth switch K5 from flowing a large current, and the damage probability of the fifth switch K5 is reduced. When the switch switching unit 130 controls the two dc voltage input terminals IN to be connected IN series, the third switch K3 and the fourth switch K4 are opened, and the fifth switch K5 is closed. When the switch switching unit 130 controls the two dc voltage inputs IN to switch from series to parallel, the third switch K3 and the fourth switch K4 switch from open to closed, and the fifth switch K5 switches from closed to open. Before the third switch K3 and the fourth switch K4 are closed, the first switch K1 is opened, and the current passes through the branch where the current limiting module 141 is located, so that the current limiting module 141 can prevent the third switch K3 and the fourth switch K4 from flowing a large current, and the damage probability of the third switch K3 and the fourth switch K4 is reduced.

With continued reference to fig. 8, the control unit 150 is further configured to form a third control signal ctrl3, a fourth control signal ctrl4, and a fifth control signal ctrl5 according to the switching instruction, the third switch K3 is configured to operate according to the third control signal ctrl3, the fourth switch K4 is configured to operate according to the fourth control signal ctrl4, and the fifth switch K5 is configured to operate according to the fifth control signal ctrl 5; in the same period, the fifth control signal ctrl5 has a delay with respect to the second control signal ctrl2, or the third control signal ctrl3 and the fourth control signal ctrl4 have a delay with respect to the second control signal ctrl 2.

Specifically, before the control unit 150 obtains the switching instruction, when the switch switching unit 130 controls the two dc voltage input terminals IN to be connected IN parallel, the first switch K1, the third switch K3, and the fourth switch K4 are closed, and the second switch K2 and the fifth switch K5 are opened. When the control unit 150 obtains the switching command, the switching command is that the connection state between the dc voltage input terminals IN is switched from parallel to series, and the control unit 150 forms the first control signal ctrl1, the second control signal ctrl2, the third control signal ctrl3, the fourth control signal ctrl4, and the fifth control signal ctrl5 according to the switching command. The first switch K1 is turned off according to the first control signal ctrl1, the third switch K3 is turned off according to the third control signal ctrl3, the fourth switch K4 is turned off according to the fourth control signal ctrl4, then the second switch K2 is turned on according to the second control signal ctrl2, and then the fifth switch K5 is turned on according to the fifth control signal ctrl5, so that the current on the fifth switch K5 passes through the branch where the second switch K2 is located, the current limiting module 141 can prevent the fifth switch K5 from flowing a large current, and the damage probability of the fifth switch K5 is reduced. After the switching is finished, the control unit 150 forms the first control signal ctrl1 when the output voltage is equal to the first threshold voltage, and the first switch K1 is closed according to the first control signal ctrl 1. At this time, the first switch K1 and the fifth switch K5 are closed, and the second switch K2, the third switch K3 and the fourth switch K4 are opened, so that the connection state between the dc voltage input terminals IN is switched from parallel connection to series connection. When the control unit 150 acquires the switching command again, the switching command is that the connection state between the dc voltage input terminals IN is switched from serial to parallel, and the control unit 150 forms the first control signal ctrl1, the second control signal ctrl2, the third control signal ctrl3, the fourth control signal ctrl4 and the fifth control signal ctrl5 according to the switching command. The first switch K1 is opened according to the first control signal ctrl1, the fifth switch K5 is opened according to the fifth control signal ctrl5, then the second switch K2 is closed according to the second control signal ctrl2, the third switch K3 is closed according to the third control signal ctrl3, and the fourth switch K4 is closed according to the fourth control signal ctrl4, so that the current on the third switch K3 and the fourth switch K4 passes through the branch where the second switch K2 is located, the current limiting module 141 can prevent the third switch K3 and the fourth switch K4 from flowing large current, and the damage probability of the third switch K3 and the fourth switch K4 is reduced. After the switching is finished, the control unit 150 forms the first control signal ctrl1 when the output voltage is equal to the first threshold voltage, and the first switch K1 is closed according to the first control signal ctrl 1. At this time, the first switch K1, the third switch K3 and the fourth switch K4 are turned on, and the second switch K2 and the fifth switch K5 are turned off, so that the connection state between the dc voltage input terminals IN is switched from serial to parallel.

Illustratively, the switch is closed when the control signal is high, and the switch is open when the control signal is low. Before the control unit 150 obtains the switching instruction, when the switch switching unit 130 controls the two dc voltage input terminals IN to be connected IN parallel, the first control signal ctrl1, the third control signal ctrl3 and the fourth control signal ctrl4 are at a high level, the first switch K1, the third switch K3 and the fourth switch K4 are closed, the second control signal ctrl2 and the fifth control signal ctrl5 are at a low level, and the second switch K2 and the fifth switch K5 are opened. When the control unit 150 obtains the switching instruction, the switching instruction is that the connection state between the dc voltage input ends IN is switched from parallel to series, the first control signal ctrl1, the third control signal ctrl3 and the fourth control signal ctrl4 provided by the control unit 150 are low level, the first switch K1, the third switch K3 and the fourth switch K4 are opened, then the second control signal ctrl2 outputs the high level preferentially to the fifth control signal ctrl5, the second switch K2 is closed first, then the fifth switch K5 is closed, so that the current on the fifth switch K5 is ensured to pass through the branch where the second switch K2 is located, and the current limiting module 141 can prevent the fifth switch K5 from flowing through a large current, and reduce the damage probability of the fifth switch K5. After the switching is finished, the control unit 150 outputs the first control signal ctrl1 at a high level when the output voltage is equal to the first threshold voltage, and the first switch K1 is closed, so that the branch where the second switch K2 is located is prevented from consuming electric energy. At this time, the first switch K1 and the fifth switch K5 are closed, and the second switch K2, the third switch K3 and the fourth switch K4 are opened, so that the connection state between the dc voltage input terminals IN is switched from parallel connection to series connection.

Or before the control unit 150 obtains the switching instruction, when the switch switching unit 130 controls the two dc voltage input terminals IN to be connected IN series, the first control signal ctrl1 and the fifth control signal ctrl5 are at a high level, the first switch K1 and the fifth switch K5 are closed, the second control signal ctrl2 and the third control signal ctrl3 and the fourth control signal ctrl4 are at a low level, and the second switch K2, the third switch K3 and the fourth switch K4 are opened. When the control unit 150 obtains the switching instruction, the switching instruction is that the connection state between the dc voltage input ends IN is switched from series connection to parallel connection, the first control signal ctrl1 and the fifth control signal ctrl5 provided by the control unit 150 are low level, the first switch K1 and the fifth switch K5 are opened, then the second control signal ctrl2 preferentially outputs the third control signal ctrl3 and the fourth control signal ctrl4 to high level, the second switch K2 is closed first, then the third switch K3 and the fourth switch K4 are closed, and it is ensured that the current on the third switch K3 and the fourth switch K4 passes through the branch where the second switch K2 is located, so that the current limiting module 141 can avoid the third switch K3 and the fourth switch K4 from flowing large current, and the damage probability of the third switch K3 and the fourth switch K4 is reduced. After the switching is finished, the control unit 150 outputs the first control signal ctrl1 at a high level when the output voltage is equal to the first threshold voltage, and the first switch K1 is closed, so that the branch where the second switch K2 is located is prevented from consuming electric energy. At this time, the first switch K1, the third switch K3 and the fourth switch K4 are turned on, and the second switch K2 and the fifth switch K5 are turned off, so that the connection state between the dc voltage input terminals IN is switched from serial to parallel.

With continued reference to fig. 8, the input memory cell 110 includes an input capacitance Cin and the output memory cell 120 includes an output capacitance Cout; each input capacitor Cin is connected IN parallel between the positive electrode and the negative electrode of the direct-current voltage input terminal IN, and the output capacitor Cout is connected IN parallel between the positive electrode and the negative electrode of the direct-current voltage output terminal OUT.

Specifically, each input capacitor Cin may be used to store a voltage across the corresponding dc voltage input terminal IN, and the output capacitor Cout may be used to store a voltage across the dc voltage output terminal OUT. When the switching unit 130 switches the connection state between the dc voltage input terminals IN, the voltage across the output capacitor Cout is maintained unchanged instantaneously, so that the switching unit 130 is subjected to a conduction voltage drop, and then the current flowing through the switching unit 130 is limited by the current limiting unit 140, so that a large current flowing through the switching unit 130 when the switching unit 130 switches the connection state between the dc voltage input terminals IN can be avoided, and the damage probability of the switching unit 130 is reduced. Meanwhile, the input capacitor Cin and the output capacitor Cout can be prevented from discharging when the switch switching unit 130 switches the connection state between the direct-current voltage input ends IN, the switching time when the switch switching unit 130 switches the connection state between the direct-current voltage input ends IN is reduced, the electric energy waste is avoided, and the charging efficiency of the direct-current voltage output switching circuit is improved.

The embodiment of the invention also provides a direct-current voltage output switching method which is realized by adopting the direct-current voltage output switching circuit provided by any embodiment of the invention. Fig. 9 is a flowchart of a method for switching dc voltage output according to an embodiment of the present invention. As shown in fig. 9, the method includes:

S10, when the switch switching unit switches the connection state between the direct-current voltage input ends, the current limiting unit limits the current flowing through the switch switching unit.

According to the technical scheme provided by the embodiment of the invention, when the switch switching unit switches the connection state between the direct-current voltage input ends, the current limiting unit limits the current flowing through the switch switching unit, so that the large current flowing through the switch switching unit when the switch switching unit switches the connection state between the direct-current voltage input ends can be avoided, and the damage probability of the switch switching unit is reduced. Meanwhile, the input storage unit and the output storage unit can be prevented from discharging when the switch switching unit switches the connection state between the direct-current voltage input ends, the switching time when the switch switching unit switches the connection state between the direct-current voltage input ends is reduced, the electric energy waste is avoided, and the charging efficiency of the direct-current voltage output switching circuit is improved.

On the basis of the technical scheme, when the current limiting unit comprises a first switch and a current limiting module; when the switch switching unit switches the connection state between the direct-current voltage input ends, the current limiting unit limits the current flowing through the switch switching unit, and the switch switching unit comprises:

specifically, the first switch is connected in series between the direct-current voltage input end and the direct-current voltage output end, and the current limiting module is connected in parallel with the first switch; when the switch switching unit switches the connection state between the direct-current voltage input ends, the current limiting module limits the current flowing through the switch switching unit, so that the large current flowing through the switch switching unit when the switch switching unit switches the connection state between the direct-current voltage input ends is avoided, and the damage probability of the switch switching unit is reduced.

When the output voltage of the direct-current voltage output end is the first threshold voltage, the first switch operates.

Specifically, when the output voltage of the direct-current voltage output end is the first threshold voltage, the connection state between the direct-current voltage input ends is successfully switched by the switch switching unit, and the first switch can be closed in an action mode, so that the first switch bypasses the current limiting module, the voltage provided by the direct-current voltage input end is transmitted to the direct-current voltage output end through the first switch, the loss of electric energy by the current limiting module is avoided, and the charging efficiency of the direct-current voltage output switching circuit is ensured. The first threshold voltage is a voltage value of the direct-current voltage output end after the switch switching unit switches the connection state between the direct-current voltage input ends. When the switching unit switches the connection state between the dc voltage input terminals from serial to parallel, the voltage value of the dc voltage output terminal is switched from high voltage to low voltage, and the first threshold voltage is the low voltage. When the switch switching unit switches the connection state between the direct-current voltage input ends from parallel connection to series connection, the voltage value of the direct-current voltage output end is converted from low voltage to high voltage, at the moment, the first threshold voltage is high voltage, and then the first switch operates when the voltage of the direct-current voltage output end is high voltage.

On the basis of the technical scheme, the current limiting module comprises a second switch and a current limiting resistor; when the switch switching unit switches the connection state between the direct-current voltage input ends, the current limiting module limits the current flowing through the switch switching unit and comprises:

Specifically, when the current limiting module comprises a second switch and a current limiting resistor, a first end of the second switch is connected with the positive electrode of the direct-current voltage input end, and a second end of the second switch is connected with the positive electrode of the direct-current voltage output end through the current limiting resistor. When the switch switching unit switches the connection state between the direct-current voltage input ends, the current formed by the pressure difference between the direct-current voltage input ends and the direct-current voltage output ends passes through the branch where the second switch and the current limiting resistor are located, so that the current limiting module can limit the current through the current limiting resistor, the large current flowing through the switch switching unit is avoided, and the damage probability of the switch switching unit is reduced.

On the basis of the technical schemes, the switch switching unit comprises a third switch, a fourth switch and a fifth switch; when the switch switching unit switches the connection state between the direct current voltage input ends, the second switch is closed, the current limiting resistor limits the current flowing through the switch switching unit, and the switch switching unit comprises:

when the switch switching unit switches the connection state between the DC voltage input terminals from parallel connection to series connection,

In the first stage, the first switch, the third switch and the fourth switch are switched from closed to open, and the second switch is switched from open to closed;

Specifically, when the switch switching unit includes a third switch, a fourth switch and a fifth switch, the third switch is connected in series between the positive electrode of the i-th group direct current voltage input end and the positive electrode of the i+1th group direct current voltage input end, the fourth switch is connected in series between the negative electrode of the i-th group direct current voltage input end and the negative electrode of the i+1th group direct current voltage input end, and the fifth switch is connected in series between the negative electrode of the i-th group direct current voltage input end and the positive electrode of the i+1th group direct current voltage input end; wherein i is an integer greater than or equal to 1 and less than j, j being the number of groups of the DC voltage input terminals. When the connection state between the direct-current voltage input ends is parallel connection, the first switch, the third switch and the fourth switch are closed, and the second switch and the fifth switch are opened. When the connection state between the direct-current voltage input ends is switched from parallel connection to series connection by the switch switching unit, the first switch, the third switch and the fourth switch are controlled to be switched from closed to open, and meanwhile, the second switch is controlled to be switched from open to closed, so that current passes through a branch where the current limiting module is located.

In the second phase, the fifth switch is switched from off to on;

Specifically, after the second switch is closed, the fifth switch is controlled to be switched from off to on, so that the current flowing through the fifth switch is limited through the current limiting resistor in the current limiting module, the fifth switch is prevented from flowing through large current, and the damage probability of the fifth switch is reduced.

When the connection state between the DC voltage input ends is switched from serial connection to parallel connection by the switch switching unit,

In the first stage, the first switch and the fifth switch are switched from closed to open, and the second switch is switched from open to closed;

Specifically, when the connection state between the dc voltage input terminals is series, the first switch and the fifth switch are closed, and the second switch, the third switch, and the fourth switch are turned off. When the connection state between the direct-current voltage input ends is switched from series connection to parallel connection by the switch switching unit, the first switch and the fifth switch are controlled to be switched from closed to open, and meanwhile, the second switch is controlled to be switched from open to closed, so that current passes through a branch where the current limiting module is located.

In the second phase, the third switch and the fourth switch are switched from off to on.

Specifically, after the second switch is closed, the third switch and the fourth switch are controlled to be switched from off to on, so that the current flowing through the third switch and the fourth switch is limited through the current limiting resistor in the current limiting module, the third switch and the fourth switch are prevented from flowing through large current, and the damage probability of the third switch and the fourth switch is reduced.

In addition, after the switching is finished, the first switch is switched from off to on, and the second switch is switched from on to off, so that the first switch bypasses a branch where the second switch is located, the current limiting module is prevented from consuming electric energy, and the charging efficiency of the direct-current voltage output switching circuit is ensured.

On the basis of the above technical solutions, the switching method of the dc voltage output further includes:

when the current before the memory cell is output is larger than the preset current, the first switch acts.

Specifically, when the current before the storage unit is output is greater than the preset current, the direct-current voltage output switching circuit outputs a short circuit, at this time, the first switch action can be set to be turned off, and the short circuit protection of the direct-current voltage output switching circuit can be realized.

The embodiment of the invention also provides a charging pile power module. Fig. 10 is a schematic structural diagram of a charging pile power module according to an embodiment of the present invention. As shown in fig. 10, the charging pile power module includes a dc voltage output switching circuit 10 according to any embodiment of the present invention.

Specifically, the charging pile power module further includes a rectifying circuit 20 and two dc-dc conversion circuits 30, the rectifying circuit 20 is connected to the two dc-dc conversion circuits 30, the output ends of the two dc-dc conversion circuits 30 are respectively connected to a set of dc voltage input ends of the dc voltage output switching circuit 10, the rectifying circuit 20 has three output ends, namely, a first output end bus_1, a second output end bus_2 and a third output end bus_3, the first output end bus_1 and the second output end bus_2 are connected to one dc-dc conversion circuit 30, the second output end bus_2 and the third output end bus_3 are connected to the other dc-dc conversion circuit 30, and the rectifying circuit 20 converts the ac power accessed by the charging pile into dc power. The dc circuit 20 may be, for example, a rectifier circuit with a power print correction function. The direct current output by the rectifying circuit 20 is subjected to voltage conversion by the two paths of direct current-direct current conversion circuits 30, so that the direct current output by the direct current-direct current conversion circuits 30 meets the voltage requirement of the battery to be charged. For example, the dc-dc conversion circuit 30 may be a phase-shifted full-bridge circuit or a resonant conversion circuit. The parameters of the two dc-dc conversion circuits 30 may be the same, so that the voltages output by the two dc-dc conversion circuits 30 are the same. The dc voltage output terminal of the dc voltage output switching circuit 10 is connected to the battery to be charged, and is used for charging the battery to be charged.

Note that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.

Claims

1. The direct-current voltage output switching circuit is used for switching the output voltage of the charging pile power module and is characterized by comprising at least two groups of direct-current voltage input ends, at least two input storage units, a direct-current voltage output end, an output storage unit, a switch switching unit and a current limiting unit;

Each input storage unit is connected in parallel between two poles of a direct-current voltage input end, each output storage unit is connected in parallel between two poles of a direct-current voltage output end, each switch switching unit is connected with the direct-current voltage input end, each current limiting unit is connected in series between the direct-current voltage input end and the direct-current voltage output end, each switch switching unit is used for switching the connection state between the direct-current voltage input ends, each current limiting unit is used for limiting the current flowing through each switch switching unit when the switch switching unit acts, the damage probability of the switch switching unit is reduced, the switching time when the switch switching unit switches the connection state between the direct-current voltage input ends is reduced, and electric energy waste is avoided;

The current limiting unit comprises a first switch and a current limiting module;

The first switch is connected in series between the direct-current voltage input end and the direct-current voltage output end, and the current limiting module is connected in parallel with the first switch; the current limiting module is used for limiting the current flowing through the switch switching unit when the switch switching unit acts, and the first switch module is used for acting when the output voltage of the direct-current voltage output end is a first threshold voltage; the first threshold voltage is a voltage value of the direct-current voltage output end after the switch switching unit switches a connection state between the direct-current voltage input ends.

2. The direct current voltage output switching circuit of claim 1, wherein the current limiting module comprises an uncontrolled rectifier tube and a current limiting resistor;

3. The direct current voltage output switching circuit of claim 1, wherein the current limiting module comprises a second switch and a current limiting resistor;

4. A direct current voltage output switching circuit according to claim 2 or 3, further comprising a control unit;

5. A direct current voltage output switching circuit according to claim 2 or 3, further comprising a control unit and an overcurrent protection unit;

6. The direct current voltage output switching circuit of claim 5, wherein the over-current protection unit comprises a comparison subunit and an and logic subunit;

7. A direct current voltage output switching circuit according to claim 3, further comprising a control unit;

8. The direct-current voltage output switching circuit according to claim 7, wherein the switch switching unit includes a third switch, a fourth switch, and a fifth switch;

9. The direct-current voltage output switching circuit according to claim 8, wherein the control unit is further configured to form a third control signal, a fourth control signal, and a fifth control signal according to a switching instruction, the third switch is configured to operate according to the third control signal, the fourth switch is configured to operate according to the fourth control signal, and the fifth switch is configured to operate according to the fifth control signal; in the same period, the fifth control signal has a delay with respect to the second control signal, or the third control signal and the fourth control signal have a delay with respect to the second control signal.

10. The direct current voltage output switching circuit of claim 1, wherein the input memory cell comprises an input capacitance and the output memory cell comprises an output capacitance;

11. A method of switching a dc voltage output, implemented using the dc voltage output switching circuit of any one of claims 1-10; characterized by comprising the following steps:

12. The method of switching a dc voltage output of claim 11, wherein the current limiting unit comprises a first switch and a current limiting module; when the switch switching unit switches the connection state between the direct-current voltage input ends, the current limiting unit limits the current flowing through the switch switching unit, and the switch switching unit comprises:

13. The method of switching a dc voltage output of claim 12, wherein the current limiting module comprises a second switch and a current limiting resistor; when the switch switching unit switches the connection state between the direct-current voltage input ends, the current limiting module limits the current flowing through the switch switching unit, and the current limiting module comprises:

14. The method of switching a dc voltage output according to claim 13, wherein the switching unit includes a third switch, a fourth switch, and a fifth switch; when the switch switching unit switches the connection state between the direct-current voltage input ends, the second switch is closed, the current limiting resistor limits the current flowing through the switch switching unit, and the switch switching unit comprises:

In the second stage, the fifth switch is switched from off to on;

15. The method for switching a dc voltage output according to claim 12, further comprising:

16. A charging pile power module comprising the direct-current voltage output switching circuit of any one of claims 1 to 10.