CN114274826A

CN114274826A - Direct-current voltage output switching circuit, switching method and charging pile power module

Info

Publication number: CN114274826A
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: 2022-04-05

Abstract

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

Background

The existing charging pile power module is provided with two direct current-direct current conversion circuits, the two direct current-direct current conversion circuits are connected with a battery to be charged through an output series/parallel switching circuit, and the output series/parallel switching circuit can switch series or parallel connection of output ends of the two direct current-direct current conversion circuits according to the type of an electric vehicle, so that the required charging voltage can be provided for the battery to be charged through adjustment. 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 direct current-direct current conversion circuits, and when the state of the switch of the alternating current relay is switched, the phenomenon that the switch is damaged due to overlarge current is easy to occur during the switching of the switch. Or the stored electric energy is discharged before the switch is switched to reduce the current during switching of the switch, so that the switching time duration is prolonged, 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 simultaneously 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 groups 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 between two poles of one direct-current voltage input end in parallel, each output storage unit is connected between two poles of the direct-current voltage output end in parallel, the switch switching unit is connected with the direct-current voltage input end, the current limiting unit is connected between the direct-current voltage input end and the direct-current voltage output end in series, the switch switching unit is used for switching the connection state between the direct-current voltage input ends, and the current limiting unit is used for limiting current flowing through the switch switching unit when the switch switching unit acts.

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

the first switch is connected between the direct-current voltage input end and the direct-current voltage output end in series, and the current limiting module is connected with the first switch in parallel; the current limiting module is used for limiting 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 includes an uncontrolled rectifier and a current limiting resistor;

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

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

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

Optionally, the dc voltage output switching circuit further includes a control unit;

the control unit is used for forming a first control signal according to a switching instruction or according to an 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 dc voltage output switching circuit further includes 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 an 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 over-current protection unit includes a comparison subunit and an and logic subunit;

the comparison subunit is configured to form a comparison signal according to the output memory cell front current and the preset current, the and logic subunit is connected to the comparison subunit and the control unit, respectively, and the and logic subunit is configured to form 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 ith group of the direct-current voltage input ends and the positive electrode of the (i + 1) th group of the direct-current voltage input ends, the fourth switch is connected in series between the negative electrode of the ith group of the direct-current voltage input ends and the negative electrode of the (i + 1) th group of the direct-current voltage input ends, and the fifth switch is connected in series between the negative electrode of the ith group of the direct-current voltage input ends and the positive electrode of the (i + 1) th group of the direct-current voltage input ends; wherein i is an integer greater than or equal to 1 and less than j, and j is the number of groups of the direct current voltage input ends.

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 act according to the third control signal, the fourth switch is configured to act according to the fourth control signal, and the fifth switch is configured to act according to the fifth control signal; in the same period, the fifth control signal has a delay time with respect to the second control signal, or the third control signal and the fourth control signal have a delay time with respect to the second control signal.

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

each input capacitor is connected in parallel between the positive pole and the negative pole of one direct-current voltage input end, and each output capacitor is connected in parallel between the positive pole and the negative pole 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; the method comprises 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 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 current limiting 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 includes 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, and the current limiting resistor limits the current flowing through the switch switching unit, including:

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 phase, the first switch, the third switch and the fourth switch are switched from closed to closed, and the second switch is switched from closed to closed;

in a 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 series connection to parallel connection,

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

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

Optionally, the method for switching the dc voltage output further includes:

and when the current is larger than the preset current before the memory cell is output, 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 of the embodiment of the invention, the current limiting unit is arranged on the conduction loop of the switch switching unit, so that the current limiting unit limits the current flowing through the switch switching unit, 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 shortened, the waste of electric energy is avoided, and the charging efficiency of the direct-current voltage output switching circuit is improved.

Drawings

Fig. 1 is a schematic structural diagram of a dc voltage output switching circuit provided in 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 structural 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 structural 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 structural diagram of another dc voltage output switching circuit according to an embodiment of the present invention;

fig. 9 is a flowchart 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 present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

Fig. 1 is a schematic structural diagram of a dc voltage output switching circuit provided in the prior art. As shown in fig. 1, the dc voltage output switching circuit includes two sets of voltage input terminals, a voltage output terminal, 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 pole Vo1+ and the negative pole Vo 1-of the first group of voltage input ends, the second storage capacitor C2 is connected in parallel between the positive pole Vo2+ and the negative pole Vo 2-of the second group of voltage input ends, the third storage capacitor C3 is connected in parallel between the positive pole Vo + and the negative pole Vo-of the voltage output ends, the first relay switch S1 is connected in series between the positive pole Vo1+ of the first group of voltage input ends and the positive pole Vo2+ of the second group of voltage input ends, the second relay switch S2 is connected in series between the negative pole Vo 1-of the first group of voltage input ends and the negative pole Vo 2-of the second group of voltage input ends, and the third relay switch S3 is connected in series between the negative pole Vo 1-of the first group of voltage input ends and the positive pole Vo2+ of the second group of voltage input ends. 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, two groups of voltage input ends are connected in parallel at the moment, the output voltage of the voltage output end is equal to the input voltage of each group of voltage input ends, namely Vo-Vo 1-Vo 2. Where 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 high voltage needs 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 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 Vo1+ Vo 2.

During charging, when the output voltage of the dc voltage output switching circuit needs to be charged across low and high voltages, it is necessary to switch the states of the first relay switch S1, the second relay switch S2, and the third relay switch S3. Illustratively, when the output voltage of the direct-current voltage output switching circuit is switched from a low voltage to a high voltage, then 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, the first relay switch S1 and the second relay switch S2 are switched from being closed to being opened, and then, when the third relay switch S3 is immediately closed, because the voltages of the first storage capacitor C1, the second storage capacitor C2 and the third storage capacitor C3 do not suddenly change, the conduction voltage drop borne by the third relay switch S3 is the difference between the sum Vo1+ Vo2 of the input voltages of each group of voltage input terminals and the input voltage Vo1 or Vo2 of each group of voltage input terminals, and because the on-resistance of the third relay switch S3 is small, the current flowing through the third relay switch S3 is large, and the third relay switch S3 is easily 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 being closed to being opened, the first storage capacitor C1, the second storage capacitor C2 and the third storage capacitor C3 may be discharged, 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 the same time is required for recharging the first storage capacitor C1, the second storage capacitor C2 and the third storage capacitor C3 after the third relay switch S3 is closed, so that the switching time of the switch switching process is long, and in severe cases, the vehicle-end 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 causes waste of electric energy and reduces the charging efficiency of the charging process. When the output voltage of the dc 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 problems also exist during handover.

In view of the above technical problems, an embodiment of the present invention provides a dc 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 used for switching the output voltage of the charging pile power module, and includes at least two groups 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 input memory cell 110 is connected IN parallel between two poles of a dc voltage input terminal IN, the output memory cell 120 is connected IN parallel between two poles of a dc voltage output terminal OUT, the switch switching unit 130 is connected to 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 switch switching unit 130 is configured to switch a connection state between the dc voltage input terminals IN, and the current limiting unit 140 is configured to limit a current flowing through the switch switching unit 130 when the switch switching unit 130 is operated.

IN particular, fig. 2 exemplarily shows that the dc voltage output switching circuit comprises two sets of dc voltage input terminals IN, respectively a first dc voltage input terminal IN1 and a second dc voltage input terminal IN2, each set of dc voltage input terminals IN comprising a positive pole and a negative pole. Two input memory cells 110 are correspondingly provided, and each input memory cell 110 is connected IN parallel between the positive and negative poles of one dc voltage input terminal IN. Each input storage unit 110 may store an input voltage provided by a correspondingly 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 switch switching unit 130 is connected to the dc voltage input terminals IN, and can switch the connection state between the dc voltage input terminals IN to be series or parallel, so that the voltage value provided by the dc voltage input terminal IN to the dc voltage output terminal OUT can be controlled by the switch switching unit 130. When the switch switching unit 130 switches the connection state between the dc voltage input terminals IN to the series connection, the voltage value provided from the dc voltage input terminal IN to the dc voltage output terminal OUT is equal to the sum of the voltages provided from each of the dc voltage input terminals IN, and is a high voltage. For example, when the two dc voltage input terminals IN exemplarily shown IN fig. 2 provide an input voltage Vin, the voltage value Vout at the dc voltage output terminal OUT is equal to the sum of the two input voltages Vin, i.e., Vout is Vin + Vin. When the switch switching unit 130 switches the connection state between the dc voltage input terminals IN to be parallel, 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 input terminals IN exemplarily shown IN fig. 2 provide an input voltage Vin, and the voltage value Vout of the dc voltage output terminal OUT is equal to the input voltage Vin, i.e., Vout is equal to Vin. When the switch switching unit 130 switches the connection state between the dc voltage input terminals IN, the electric energy applied to the input storage unit 110 and the output storage unit 120 does not change abruptly, so that the conduction voltage drop borne by the switch switching unit 130 is the difference between the high voltage and the low voltage. The on-resistance of the switch switching unit 130 is relatively small, and the current limiting unit 140 is disposed on the on-loop of the switch switching unit 130, so that the current limiting unit 140 limits the current flowing through the switch switching unit 130, thereby preventing a large current from flowing through the switch switching unit 130 when the switch switching unit 130 switches the connection state between the dc voltage input terminals IN, and reducing the damage probability of the switch 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 dc voltage input terminals IN, the switching time when the switch switching unit 130 switches the connection state between the dc voltage input terminals IN is reduced, the waste of electric energy is avoided, and the charging efficiency of the dc voltage output switching circuit is improved.

Fig. 3 is a schematic structural 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 switch switching unit 130 when the switch switching unit 130 is activated, and the first switch K1 module is configured to be activated when an output voltage of the dc voltage output terminal OUT is a first threshold voltage.

Specifically, when the switch 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 switch switching unit 130, so that a large current flowing through the switch switching unit 130 when the switch switching unit 130 switches the connection state between the dc voltage input terminals IN may be avoided, and the probability of damage of the switch switching unit 130 is reduced. After the switch switching unit 130 successfully switches the connection state between the dc voltage input terminals IN, 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 terminal OUT is converted into the first threshold voltage, at this time, the first switch K1 may be actuated to 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, thereby avoiding the loss of electric energy of the current limiting module 141, and ensuring the charging efficiency of the dc voltage output switching circuit. The first threshold voltage is a voltage value of the dc voltage output terminal OUT after the switch switching unit 130 switches the connection state between the dc voltage input terminals IN. For example, when the switch switching unit 130 switches the connection state between the dc voltage input terminals IN from series connection to parallel connection, the voltage value of the dc voltage output terminal OUT is converted from a high voltage to a low voltage, and the first threshold voltage is a low voltage, the first switch K1 operates when the voltage of the dc voltage output terminal OUT is a low voltage. When the switch switching unit 130 switches the connection state between the dc voltage input terminals IN from parallel connection to series connection, the voltage value of the dc voltage output terminal OUT is converted from low voltage to high voltage, and the first threshold voltage is high voltage, the first switch K1 operates when the voltage of the dc voltage output terminal OUT is high voltage.

Fig. 4 is a schematic structural 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 electrode of the uncontrolled rectifier D1 is connected to the positive electrode of the dc voltage input terminal IN, and the negative electrode of the uncontrolled rectifier D1 is connected to the positive electrode of the dc voltage output terminal OUT through the current limiting resistor R1.

Specifically, the uncontrolled current diode D1 has a function of unidirectional conduction. When the switch switching unit 130 switches the connection state between the dc voltage input terminals IN, the electric energy input to the storage unit 110 and the electric energy output to the storage unit 120 will not change suddenly, so that the conduction voltage drop borne 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 non-controlled 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 current of the large current on the conducting loop, thereby reducing the current on the conducting loop of the switch switching unit 130. When the voltage of the output memory cell 120 is equal to the voltage of the input memory cell 110, the currents of the uncontrolled rectifier D1 and the current-limiting resistor R1 are zero, the voltage of the dc voltage output terminal OUT is the first threshold voltage, and the first switch K1 is controlled to operate, so that the first switch K1 bypasses the uncontrolled rectifier D1 and the current-limiting resistor R1, the voltage provided by the dc voltage input terminal IN is transmitted to the dc voltage output terminal OUT through the first switch K1, thereby avoiding the power loss of the current-limiting module 141, and ensuring the charging efficiency of the dc voltage output switching circuit.

Exemplarily, fig. 4 shows that the dc voltage output switching circuit includes two sets of dc voltage input terminals IN, which respectively provide the first dc voltage input terminal IN1 and the second dc voltage input terminal IN2 with equal input voltages Vin. When the switch switching unit 130 controls the two dc voltage input terminals IN to be IN parallel, the first switch K1 is closed, the voltage at the dc voltage input terminal IN is provided to the dc voltage output terminal OUT through the first switch K1, and the output voltage Vout at the dc voltage output terminal OUT is equal to the input voltage Vin, i.e. Vout equals to 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 does not change suddenly, the voltage stored IN the input storage unit 110 is greater than the voltage of the output storage unit 120, the conduction voltage drop borne by the switch switching unit 130 is the difference between the high voltage and the low voltage, the first switch K1 is turned off, the current flowing through the switch switching unit 130 is controlled through the uncontrolled rectifier tube D1 and the current limiting resistor R1, 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 may be actuated to 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 switching from the parallel connection to the series connection of the dc voltage input terminal IN is completed, the power loss of 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 structural 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; a first terminal of the second switch K2 is connected to the positive terminal of the dc voltage input terminal IN, and a second terminal of the second switch K2 is connected to the positive terminal of the dc voltage output terminal 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 of the second switch K2 and the current limiting resistor R1, so that the current limiting module 141 can limit the bidirectional current. Exemplarily, fig. 5 shows that the dc voltage output switching circuit includes two sets of dc voltage input terminals IN, which respectively provide the first dc voltage input terminal IN1 and the second dc voltage input terminal IN2 with equal input voltages Vin. When the switch switching unit 130 controls the two dc voltage input terminals IN to be IN a parallel state, the first switch K1 is closed, the second switch K2 is opened, the voltage at the dc voltage input terminal IN is provided to the dc voltage output terminal OUT through the first switch K1, and the output voltage Vout at the dc voltage output terminal OUT is equal to the input voltage Vin, i.e., Vout is equal to 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 does not change suddenly, the voltage stored IN the input storage unit 110 is greater than the voltage of the output storage unit 120, the conduction voltage drop borne by the switch switching unit 130 is the difference between the high voltage and the low voltage, the first switch K1 is turned off, the second switch K2 is turned on, the current flowing through the switch switching unit 130 is controlled through the second switch K2 and the current-limiting resistor R1, 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 at the dc voltage output terminal OUT reaches the first threshold voltage, the first threshold voltage is a high voltage, i.e., Vout is Vin + Vin. The voltage stored IN the input memory cell 110 is equal to the voltage stored IN the output memory cell 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 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, and the switching from the parallel connection to the series connection of the dc voltage input terminal IN is completed.

When the connection state of the dc voltage input terminals IN is changed from series connection to parallel connection, when the switch switching unit 130 controls the two dc voltage input terminals IN to be IN series connection, the first switch K1 is closed, the second switch K2 is opened, 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 sum of the input voltages Vin, that is, Vout is equal to Vin + Vin. When the connection state of the dc voltage input terminal IN is converted from series connection to parallel connection, the voltage of the output storage unit 120 does not change suddenly, the voltage stored IN the output storage unit 110 is greater than the voltage input to the storage unit 120, the conduction voltage drop borne by the switch switching unit 130 is the difference between the high voltage and the low voltage, the first switch K1 is turned off, the second switch K2 is turned on, the current flowing through the switch switching unit 130 is controlled by the second switch K2 and the current limiting resistor R1, 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 is Vin, the voltage stored IN the input memory cell 110 is equal to the voltage of the output memory cell 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 may be closed, 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 structural 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 command 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 an output voltage provided by the dc voltage output terminal OUT and an input voltage provided by the dc voltage input terminal IN. For example, the control unit 150 may collect the output voltage provided by the dc voltage output terminal OUT and the input voltage provided by the dc voltage input terminal IN through the sampling circuit. 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. Illustratively, the dc voltage output switching circuit includes two sets of dc voltage input terminals IN, which respectively provide the first dc voltage input terminal IN1 and the second dc voltage input terminal IN2 with equal input voltages Vin. When the switch switching unit 130 controls the two dc voltage input terminals IN to be switched from parallel to series, the first threshold voltage that the output voltage Vout of the dc voltage output terminal OUT needs to reach is a high voltage, that is, Vout is 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 two input voltages Vin provided by two sets of dc voltage input terminals IN. When the output voltage Vout at the dc voltage output terminal OUT is equal to the sum of the two input voltages Vin provided at the two 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. When the switch switching unit 130 controls the two dc voltage input terminals IN to be switched from series connection to parallel connection, a first threshold voltage that the output voltage Vout of the dc voltage output terminal OUT needs to reach is a low voltage, that is, Vout is equal to 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 two input voltages Vin provided by two sets of dc voltage input terminals IN. When the output voltage Vout at the dc voltage output terminal OUT is equal to the two input voltages Vin provided by the two 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 shows 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 may also be activated according to the first control signal ctrl1, which is not described herein again.

Fig. 7 is a schematic structural 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 memory cell front 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 pre-output memory cell current isec is the current before the memory cell 120 is output, and as shown IN fig. 7, the pre-output memory cell current isec is the current between the dc voltage input terminal IN and the dc voltage output terminal OUT. The preset current ipro is a preset current. Illustratively, the preset current ipro may be a current short 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 current isec before outputting the memory cell and the preset current ipro, and then form a first switch control signal ctrl11 for controlling the first switch K1 by using the first control signal ctrl 1. When the dc voltage output switching circuit works normally, the current isec before outputting the storage unit is smaller than the preset current ipro, the over-current protection unit 160 forms the first switch control signal ctrl11 according to the first control signal ctrl1, and the first switch K1 operates according to the first switch control signal ctrl 11. When the output of the direct-current voltage output switching circuit is short-circuited, the current isec before the storage unit is larger than the preset current ipro, the overcurrent protection unit 160 forms a first switch control signal ctrl11 according to the fact that the current isec before the storage unit is larger than the preset current ipro, and the first switch K1 is turned off according to the first switch control signal ctrl11, so that short-circuit protection of the direct-current voltage output switching circuit can be achieved.

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

Specifically, 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 pre-output memory cell current isec is the current before the memory cell 120 is output, and as shown IN fig. 7, the pre-output memory cell current isec is the current between the dc voltage input terminal IN and the dc voltage output terminal OUT. The preset current ipro is a preset current. Illustratively, the preset current ipro may be a current short protection threshold current. When the dc voltage output switching circuit is operating normally, the output memory cell pre-current isec is smaller than the preset current ipro, the comparing unit 161 forms a comparison signal comp according to the output memory cell pre-current isec and the preset current ipro, and the comparison signal comp can control the first switch K1 to be closed, for example, the comparison signal comp can 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, when the first switch K1 is closed according to the first switch control signal ctrl 11. That is, when the dc voltage output switching circuit normally operates, 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 operating according to the first control signal ctrl 1. When the output of the dc voltage output switching circuit is short-circuited, the output memory cell pre-current isec is greater than the preset current ipro, the comparing unit 161 forms a comparison signal comp according to the output memory cell pre-current isec and the preset current ipro, and the comparison signal comp can control the first switch K1 to be turned off, for example, the comparison signal comp can be at a low 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, where the state of the first switch 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 switch control signal ctrl11, so that short-circuit protection of the dc voltage output switching circuit can be achieved.

In addition, when the current limiting module 141 includes the uncontrolled rectifier D1 and the current limiting resistor R1, or 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 turned off, the short-circuit protection of the switch switching unit 130 can be realized by suppressing the short-circuit current through the current limiting resistor R1. Meanwhile, the comparison signal comp may also be fed back to the control unit 150, and when the output of the dc voltage output switching circuit is short-circuited, the control unit 150 controls the dc voltage input terminal IN to stop providing the input voltage according to the comparison signal comp, so as to further protect 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 a control unit 150; the control unit 150 is configured to form a second control signal ctrl2 according to a switching command 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 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 switching unit 130. When the switch switching unit 130 is configured to switch the connection state between the dc voltage input terminals IN, the control unit 150 first forms the second control signal ctrl2 according to the switching instruction, the second switch K2 may control the second switch K2 to be closed according to the second control signal ctrl2, and then controls the switch switching unit 130 to switch the connection state between the dc voltage input terminals IN according to the switching instruction, so that when the switch switching unit 130 switches the connection state between the dc voltage input terminals IN, the current passes through the branch where the second switch K2 is located, so that the current is limited by the current-limiting resistor R1, thereby avoiding a large current flowing through the switch switching unit 130, and reducing the damage probability of the switch switching unit 130. After the switch-off unit 130 is configured to switch the connection state between the dc voltage input terminals IN, the control unit 150 forms a first control signal ctrl1 according to the output voltage 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, power loss of the current-limiting module 141 is avoided, and charging efficiency of the dc voltage output switching circuit is ensured.

Fig. 8 is a schematic structural 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 pole of the i-th group of DC voltage input terminals IN and the positive pole of the i + 1-th group of DC voltage input terminals IN, the fourth switch K4 is connected IN series between the negative pole of the i-th group of DC voltage input terminals IN and the negative pole of the i + 1-th group of DC voltage input terminals IN, and the fifth switch K5 is connected IN series between the negative pole of the i-th group of DC voltage input terminals IN and the positive pole of the i + 1-th group of DC voltage input terminals IN; wherein i is an integer greater than or equal to 1 and less than j, and j is 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, a first dc voltage input terminal IN1 and a second dc voltage input terminal IN2, a third switch K3 connected IN series between the positive pole of the first dc voltage input terminal IN1 and the positive pole of the second dc voltage input terminal IN2, a fourth switch K4 connected IN series between the negative pole of the first dc voltage input terminal IN1 and the negative pole of the second dc voltage input terminal IN2, and a fifth switch K5 connected IN series between the negative pole of the first dc voltage input terminal IN1 and the positive pole 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 input terminals IN to be switched from parallel to series, the third switch K3 and the fourth switch K4 are switched from closed to open, and the fifth switch K5 is switched from open to closed. Before the fifth switch K5 is 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 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 input terminals IN to be switched from series to parallel, the third switch K3 and the fourth switch K4 are switched from open to closed, and the fifth switch K5 is switched 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 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 be actuated according to the third control signal ctrl3, the fourth switch K4 is configured to be actuated according to the fourth control signal ctrl4, and the fifth switch K5 is configured to be actuated 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 acquires 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 instruction, the switching instruction is that the connection state between the dc voltage input terminals IN is switched from parallel connection to series connection at this time, 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 instruction. 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 flowing through 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 the moment, 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 direct-current voltage input ends IN is switched from parallel connection to series connection. When the control unit 150 acquires the switching instruction again, the switching instruction is that the connection state between the dc voltage input terminals IN is switched from series connection to parallel connection at this time, 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 instruction. 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 firstly closed according to the second control signal ctrl2, then 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 is ensured to flow through the branch where the second switch K2 is located, the current limiting module 141 can avoid the third switch K3 and the fourth switch K4 from flowing through a large current, and the probability of damage 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 the moment, 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, so that the connection state between the direct-current voltage input ends IN is switched from series connection to parallel connection.

For example, the switch is closed when the control signal is at a high level, and the switch is opened when the control signal is at a low level. Before the control unit 150 acquires 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 a switching instruction, at this time, the switching instruction is that the connection state between the dc voltage input terminals 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 at a low level, the first switch K1, the third switch K3, and the fourth switch K4 are turned off, then the second control signal ctrl2 prioritizes the fifth control signal ctrl5 to output a high level, the second switch K2 is turned on first, and then the fifth switch K5 is turned on, so that the current on the fifth switch K5 is ensured to flow through the branch where the second switch K2 is located, so that the current limiting module 141 can avoid the fifth switch K5 from flowing a large current, and reduce the damage probability of the fifth switch K5. After the switching is finished, the first control signal ctrl1 output by the control unit 150 is at a high level when the output voltage is equal to the first threshold voltage, and the first switch K1 is closed, so as to avoid the power loss of the branch where the second switch K2 is located. At the moment, 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 direct-current voltage input ends IN is switched from parallel connection to series connection.

Alternatively, 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, 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 a switching instruction, the switching instruction is that the connection state between the dc voltage input terminals IN is switched from series connection to parallel connection at this time, the first control signal ctrl1 and the fifth control signal ctrl5 provided by the control unit 150 are at a low level, the first switch K1 and the fifth switch K5 are open, then the second control signal ctrl2 prioritizes the third control signal ctrl3 and the fourth control signal ctrl4 to output a high level, the second switch K2 is first closed, then the third switch K3 and the fourth switch K4 are closed, 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 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. After the switching is finished, the first control signal ctrl1 output by the control unit 150 is at a high level when the output voltage is equal to the first threshold voltage, and the first switch K1 is closed, so as to avoid the power loss of the branch where the second switch K2 is located. At the moment, 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, so that the connection state between the direct-current voltage input ends IN is switched from series connection to parallel connection.

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

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

The embodiment of the invention also provides a switching method of the direct-current voltage output, 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 a 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 dc voltage input terminals, the current limiting unit limits the current flowing through the switch switching unit.

According to the technical scheme of 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 shortened, the waste of electric energy is avoided, and the charging efficiency of the direct-current voltage output switching circuit is improved.

On the basis of the technical scheme, 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 voltage input ends, the current limiting unit limits the current flowing through the switch switching unit, and the current limiting 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 acts.

Specifically, when the output voltage of the dc voltage output terminal is the first threshold voltage, the switch switching unit is successful in switching the connection state between the dc voltage input terminals at this time, and the first switch can be closed by action, so that the first switch bypasses the current limiting module, the voltage provided by the dc voltage input terminal is transmitted to the dc voltage output terminal through the first switch, the loss of electric energy by the current limiting module is avoided, and the charging efficiency of the dc 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. Illustratively, when the switch switching unit switches the connection state between the dc voltage input terminals from series connection to parallel connection, the voltage value of the dc voltage output terminal is converted from a high voltage to a low voltage, and the first threshold voltage is a 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 the first switch acts 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 the current limiting module 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 anode of the direct-current voltage input end, and a second end of the second switch is connected with the anode 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, and the current limiting resistor limits the current flowing through the switch switching unit, and the switch switching unit comprises:

in the first stage, the first switch, the third switch and the fourth switch are switched from on to off, and the second switch is switched from off to on;

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 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, and j is the number of groups of the direct current voltage input ends. 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 closed. When the switch switching unit switches the connection state between the direct-current voltage input ends from parallel connection to series connection, the first switch, the third switch and the fourth switch are controlled to be switched from on to off, and the second switch is controlled to be switched from off to on, so that current passes through the branch where the current limiting module is located.

In the second stage, 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 a large current, and the damage probability of the fifth switch is reduced.

in the first stage, the first switch and the fifth switch are switched from on to off, and the second switch is switched from off to on;

specifically, when the connection state between the dc voltage input terminals is series connection, the first switch and the fifth switch are closed, and the second switch, the third switch, and the fourth switch are opened. When the switch switching unit switches the connection state between the direct-current voltage input ends from series connection to parallel connection, the first switch and the fifth switch are controlled to be switched from on to off, and the second switch is controlled to be switched from off to on, so that current passes through the 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 a current limiting resistor in the current limiting module, the third switch and the fourth switch are prevented from flowing 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 circuit where the second switch is located, electric energy loss of the current limiting module is avoided, and the charging efficiency of the direct-current voltage output switching circuit is ensured.

On the basis of the above technical solutions, the method for switching 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 is larger than the preset current before the memory cell is output, the direct-current voltage output switching circuit outputs a short circuit, and at this time, the first switch can be set to be turned off, so that 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 comprises a rectifying circuit 20 and two direct current-direct current conversion circuits 30, the rectifying circuit 20 is connected with the two direct current-direct current conversion circuits 30, the output ends of the two direct current-direct current conversion circuits 30 are respectively connected with a group of direct current voltage input ends of the direct current voltage output switching circuit 10, the rectifying circuit 20 has three output ends which are respectively 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 with one direct current-direct current conversion circuit 30, the second output end BUS _2 and the third output end BUS _3 are connected with the other direct current-direct current conversion circuit 30, and the rectifying circuit 20 converts alternating current accessed by the charging pile into direct current. Illustratively, the dc circuit 20 may be a rectifier circuit having a power printing correction function. The direct current output by the rectification circuit 20 is converted in voltage by the two 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 end 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.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. 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, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A direct-current voltage output switching circuit is used for switching output voltage of a 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;

2. The direct voltage output switching circuit according to claim 1, wherein the current limiting unit includes a first switch and a current limiting module;

3. The dc voltage output switching circuit according to claim 2, wherein the current limiting module comprises an uncontrolled rectifier and a current limiting resistor;

4. The dc voltage output switching circuit according to claim 2, wherein the current limiting module includes a second switch and a current limiting resistor;

5. The direct-voltage output switching circuit according to claim 3 or 4, further comprising a control unit;

6. The direct-current voltage output switching circuit according to claim 3 or 4, further comprising a control unit and an overcurrent protection unit;

7. The direct-current voltage output switching circuit according to claim 6, wherein the overcurrent protection unit includes a comparison subunit and an AND logic subunit;

8. The direct-voltage output switching circuit according to claim 4, further comprising a control unit;

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

10. The direct voltage output switching circuit according to claim 9, 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 be activated according to the third control signal, the fourth switch is configured to be activated according to the fourth control signal, and the fifth switch is configured to be activated according to the fifth control signal; in the same period, the fifth control signal has a delay time with respect to the second control signal, or the third control signal and the fourth control signal have a delay time with respect to the second control signal.

11. The dc voltage output switching circuit according to claim 1, wherein the input storage unit includes an input capacitance, and the output storage unit includes an output capacitance;

12. A method for switching a dc voltage output, which is implemented by using the dc voltage output switching circuit of any one of claims 1-11; it is characterized by comprising:

13. The method of switching a dc voltage output according to claim 12, wherein 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 current limiting unit comprises:

14. The method of switching a dc voltage output according to claim 13, 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:

15. The method of switching a direct current voltage output according to claim 14, wherein 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, and the current limiting resistor limits the current flowing through the switch switching unit, including:

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

16. The method of switching a dc voltage output according to claim 13, further comprising:

17. A charging pile power module comprising the dc voltage output switching circuit according to any one of claims 1 to 11.