WO2022217619A1

WO2022217619A1 - Voltage conversion circuit, voltage conversion apparatus, voltage conversion chip and charging device

Info

Publication number: WO2022217619A1
Application number: PCT/CN2021/087947
Authority: WO
Inventors: 杨帅; 赵德琦; 吴壬华
Original assignee: 深圳欣锐科技股份有限公司
Priority date: 2021-04-17
Filing date: 2021-04-17
Publication date: 2022-10-20
Also published as: CN114270655A

Abstract

The embodiments of the present application provide a voltage conversion circuit, a voltage conversion apparatus, a voltage conversion chip and a charging device. The voltage conversion circuit comprises: a charging input interface, a charging output interface, a filtering module, a switch module and a voltage conversion module, wherein the filtering module is used for suppressing a common-mode current signal; the switch module is used for being switched on when a voltage value of the charging input interface is not less than a preset voltage value, and being switched off when the voltage value of the charging input interface is less than the preset voltage value, such that the filtering module only operates when the voltage value of the charging input interface is not less than the preset voltage value; and the voltage conversion module is used for converting an input voltage value of the charging input interface into the preset voltage value and then outputting same by means of the charging output interface. In this way, the suppression of a common-mode current signal can be realized, thereby improving the operation stability and safety of a circuit system.

Description

Voltage conversion circuit, voltage conversion device, voltage conversion chip and charging equipment

technical field

The present application relates to the field of vehicle charging, and in particular to a voltage conversion circuit, a voltage conversion device, a voltage conversion chip and a charging device.

Background technique

In order to increase the mileage of new energy electric vehicles on a single charge, most OEMs choose to increase the voltage of the on-board battery pack. This allows the battery pack to store more energy, thereby increasing the driving range. At the current stage, the output voltage of the battery pack of most electric vehicles with a single-charge NDC mileage of 400-500KM is 300-450V. In order to increase the NDC mileage on a single charge to 800-1000KM, a current implementation method is to increase the output voltage of the on-board battery pack of the new energy vehicle to 800V or even higher. However, at present, the highest output voltage of some ground DC charging piles is usually 500V, and the highest output voltage of a small part is 750V. Therefore, when future electric vehicles choose to increase the voltage of the battery pack in order to increase the NDC mileage, they will encounter that the maximum output voltage of the ground DC fast charging pile is lower than the voltage of the battery pack, which will cause the ground charging pile to be unable to be used for electric vehicles. Car charging. At present, in order to solve the problem that the output voltage of the charging pile is lower than the voltage of the battery pack and cannot be charged, a first-level voltage conversion device can be added between the charging pile and the battery pack. By raising the output voltage of the charging pile to be higher than the voltage of the battery pack, the purpose of charging new energy electric vehicles is realized. However, the current working stability and safety of the circuit system related to the voltage boosting device are not enough.

SUMMARY OF THE INVENTION

The embodiments of the present application provide a voltage conversion circuit, a voltage conversion device, a voltage conversion chip and a charging device, so as to improve the safety and stability of the circuit system of the vehicle during charging.

In a first aspect, an embodiment of the present application provides a voltage conversion circuit, including: a charging input interface, a charging output interface, a filter module, a switch module, and a voltage conversion module;

Wherein, the filtering module is used for suppressing the common mode current signal;

The switch module is configured to be turned on when the voltage value of the charging input interface is not less than a preset voltage value, and disconnected when the voltage value of the charging input interface is less than the preset voltage value, so as to realize the first A filter module works only when the voltage value of the charging input interface is not less than the preset voltage value;

The voltage conversion module is configured to convert the input voltage value of the charging input interface into the preset voltage value and output it through the charging output interface.

Optionally, the switch module includes a first switch and a second switch; the first end of the first switch is connected to the positive pole of the charging input interface, and the second end of the first switch is connected to the charging output The positive pole of the interface is connected, the first end of the second switch is connected to the negative pole of the charging input interface, and the second end of the second switch is connected to the negative pole of the charging output interface.

Optionally, the filter module includes a first filter and a second filter; the first end of the first filter is connected to the charging input interface, and the second end of the first filter is connected to the charging input interface. The first end of the voltage conversion module is connected; the first end of the second filter is connected with the second end of the voltage conversion module, and the second end of the second filter is connected with the charging output interface.

Optionally, the first filter includes a first positive coil and a first negative coil, the second filter includes a second positive coil and a second negative coil; the first end of the first positive coil is connected to the The positive electrode of the charging input interface is connected, the second end of the first positive coil is connected to the positive electrode of the first end of the voltage conversion module, and the first end of the first negative coil is connected to the negative electrode of the charging input interface. The second end of the first negative coil is connected to the negative electrode of the first end of the voltage conversion module; the first end of the second positive coil is connected to the positive electrode of the second end of the voltage conversion module, so The second end of the second positive coil is connected to the positive electrode of the charging output interface, the first end of the second negative coil is connected to the negative electrode of the second end of the voltage conversion module, and the first end of the second negative coil is connected to the negative electrode of the second end of the voltage conversion module. The two ends are connected to the negative pole of the charging output interface.

Optionally, the number of turns and the polarity of the first positive coil and the first negative coil are respectively the same, and the number of turns and the polarity of the second positive coil and the second negative coil are respectively the same.

Optionally, the first filter includes a first main capacitor and a first auxiliary capacitor, the second filter includes a second main capacitor and a second auxiliary capacitor; the positive electrode of the charging input interface is connected to the first capacitor. The first terminal of the main capacitor is connected to the positive pole of the first terminal of the voltage conversion module after being combined, and the second terminal of the first main capacitor is combined with the second terminal of the first auxiliary capacitor and then grounded. The negative pole of the charging input interface is combined with the first terminal of the first auxiliary capacitor and then connected to the negative pole of the first terminal of the voltage conversion module; the positive pole of the charging output interface is connected to the first terminal of the second main capacitor. After one end is combined, it is connected to the positive pole of the second end of the voltage conversion module, the second end of the second main capacitor and the second end of the second auxiliary capacitor are combined and grounded, and the charging output interface The negative electrode is combined with the first end of the second auxiliary capacitor and connected to the negative electrode of the second end of the voltage conversion module.

Optionally, the first filter includes a first common-mode inductor and a first common-mode capacitor, a first end of the first common-mode capacitor is connected to the charging input interface, and the first common-mode capacitor is connected to the charging input interface. The second end is connected to the first end of the first common mode inductor, the second end of the first common mode inductor is connected to the first end of the voltage conversion module; the second filter includes a second common mode inductor. A mode inductor and a second common mode capacitor, the first end of the second common mode inductor is connected to the second end of the voltage conversion module, and the second end of the second common mode inductor is connected to the second common mode The first end of the capacitor is connected, and the second end of the second common mode capacitor is connected to the charging output interface.

In a second aspect, an embodiment of the present application provides a voltage conversion device, where the voltage conversion device includes the voltage conversion circuit described in the first aspect above.

In a third aspect, an embodiment of the present application provides a voltage conversion chip, where the voltage conversion chip includes the voltage conversion circuit described in the first aspect above.

In a fourth aspect, an embodiment of the present application provides a charging device, where the charging device includes the voltage conversion circuit described in the first aspect.

It can be seen that in the embodiment of the present application, the voltage conversion circuit includes a charging input interface, a charging output interface, a filter module, a switch module and a voltage conversion module, wherein the filter module is used to suppress the common mode current signal, and the The switch module is configured to be turned on when the voltage value of the charging input interface is not less than the preset voltage value, and disconnected when the voltage value of the charging input interface is less than the preset voltage value, so as to realize that the filter module only Working when the voltage value of the charging input interface is not less than the preset voltage value, the voltage conversion module is configured to convert the input voltage value of the charging input interface into the preset voltage value and pass the charging Output interface output. In this way, when the voltage of the ground charging pile is lower than the voltage required by the battery pack, that is, the voltage value of the charging input interface is lower than the preset voltage value, when the voltage conversion module in the voltage conversion circuit is used to convert the output voltage value of the charging pile, The filter module can suppress the common mode current signal and improve the working stability of the circuit system. When the maximum output voltage of the ground charging pile is higher than the required voltage of the battery pack, the current can be prevented from passing through the filter module, so as to prevent the filter module from being damaged by heat and improve the safety of the circuit system.

Description of drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

FIG. 1 is a schematic diagram of a charging system provided by an embodiment of the present application;

FIG. 2 is a schematic diagram of a module of a voltage conversion circuit provided by an embodiment of the present application;

3 is a schematic diagram of a switch module of a voltage conversion circuit provided by an embodiment of the present application;

4 is a schematic diagram of a filtering module of a voltage conversion circuit provided by an embodiment of the present application;

5 is a schematic diagram of a filter of a voltage conversion circuit provided by an embodiment of the present application;

6 is a schematic diagram of a filter of another voltage conversion circuit provided by an embodiment of the present application;

7 is a schematic diagram of a filter of another voltage conversion circuit provided by an embodiment of the present application;

FIG. 8 is a schematic structural diagram of a voltage conversion device provided by an embodiment of the present application;

9 is a schematic structural diagram of a voltage conversion chip provided by an embodiment of the present application;

FIG. 10 is a schematic structural diagram of a charging device provided by an embodiment of the present application.

Detailed ways

In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are Some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The terms "first", "second" and the like in the description and claims of the present application and the above drawings are used to distinguish different objects, rather than to describe a specific order. Furthermore, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but optionally also includes unlisted steps or units, or optionally also includes For other steps or units inherent to these processes, methods, products or devices.

Reference herein to an "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor a separate or alternative embodiment that is mutually exclusive of other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

In order to better understand the technical solutions of the embodiments of the present application, the voltage conversion circuits that may be involved in the embodiments of the present application will be introduced below.

Please refer to FIG. 1. FIG. 1 is a schematic diagram of a charging system provided by an embodiment of the present application. The charging system includes a charging pile, a voltage conversion device, and a battery pack. The charging pile may be a ground DC charging pile, which is used for battery powered by. The voltage conversion device is respectively connected to the charging pile and the battery pack, and the voltage conversion device is used to convert the output voltage of the charging pile to a voltage suitable for the battery pack. For example, the output voltage of the charging pile is 500V, and the voltage The conversion device can increase the voltage of 500V to 800V, wherein the voltage conversion device is a device for converting from DC to DC. The battery pack is used to store the obtained electrical energy and to supply power to the vehicle. The voltage conversion device can be integrated on the vehicle together with the battery pack, the voltage conversion device can also be an independent detachable device, and the voltage conversion device can also be integrated in the charging pile.

At present, in order to increase the mileage of the car, most car manufacturers have increased the output voltage of the car's battery pack from the original 300-450V to 800V or even higher, and due to the slow infrastructure construction of electric vehicle charging piles nationwide and even around the world, The maximum output voltage of most charging piles is still lower than the voltage of the current battery pack. Therefore, when the car is charging, there may be two modes, one is the bypass mode when the voltage of the charging pile is higher than or equal to the voltage of the battery pack, and the other is the boost mode when the voltage of the charging pile is lower than the voltage of the battery pack model. In order to suppress the common mode current signal, the voltage conversion device often adds a filter module, but the rated current of the filter module in the boost mode is different from the rated current in the bypass mode, which will cause the voltage conversion device in a certain one. In the mode, the filter module may be heated and damaged, and the safety of the circuit system cannot be guaranteed.

In conjunction with the above description, the voltage conversion circuit will be described below according to embodiments. Please refer to FIG. 2 , which is a schematic block diagram of a voltage conversion circuit provided by an embodiment of the present application.

The voltage conversion circuit includes a charging input interface 210, a charging output interface 250, a filter module 220, a switch module 230 and a voltage conversion module 240; wherein, the filter module 220 is used to suppress the common mode current signal; the switch module 230 is used for It is turned on when the voltage value of the charging input interface is not less than the preset voltage value, and is turned off when the voltage value of the charging input interface 210 is less than the preset voltage value, so that the filter module 220 can only The voltage value of the charging input interface 210 works when the voltage value is not less than the preset voltage value; the voltage conversion module 240 is used to convert the input voltage value of the charging input interface 210 to the preset voltage value and then pass through the predetermined voltage value. The charging output interface 250 outputs.

Among them, the common mode current signal refers to the current signal generated in the circuit system that is not necessarily equal in size but has the same direction or phase. The common-mode current signal will cause common-mode interference in the circuit system. Common-mode interference refers to the interference between the two signal lines to the ground. Superimpose the same voltage), then it is called common mode interference. Common mode interference will cause certain damage to the circuit system, making the circuit system unable to work normally. When the car is charging, the high-frequency switching operation of the power conversion device will bring about the electromagnetic interference (Electro Magnetic Interference, EMI) problem, which affects the working stability of the circuit system. Therefore, it is necessary to add a filter module to the voltage conversion circuit to suppress EMI common. mode interference.

In specific implementation, the switch module 230 is connected to the charging input interface 210 and the charging output interface 250 respectively, so that the switch module 230 can control whether the voltage conversion module 240 works. That is, in the boost mode, the switch module 230 is in an off state, and the voltage conversion module 240 is working at this time; in the bypass mode, the switch module 230 is in an on state, and the voltage conversion module 240 is in a non-working state at this time. . This can prevent current from passing through the filter module 220, causing the filter module 220 to be damaged by heat.

It can be seen that in this example, the voltage conversion circuit includes a charging input interface, a charging output interface, a filter module, a switch module and a voltage conversion module, wherein the filter module is used for suppressing the common mode current signal, and the switch module is used for Turn on when the voltage value of the charging input interface is not less than the preset voltage value, and turn off when the voltage value of the charging input interface is less than the preset voltage value, so as to realize that the filter module only works when the charging It works when the voltage value of the input interface is not less than the preset voltage value, and the voltage conversion module is configured to convert the input voltage value of the charging input interface into the preset voltage value and output through the charging output interface. In this way, when the voltage of the ground charging pile is lower than the voltage required by the battery pack, that is, the voltage value of the charging input interface is lower than the preset voltage value, when the voltage conversion module in the voltage conversion circuit is used to convert the output voltage value of the charging pile, The filter module can suppress the common mode current signal and improve the working stability of the circuit system. When the maximum output voltage of the ground charging pile is higher than the required voltage of the battery pack, the current can be prevented from passing through the filter module, so as to prevent the filter module from being damaged by heat and improve the safety of the circuit system.

In a possible example, the switch module includes a first switch K1 and a second switch K2; the first end of the first switch K1 is connected to the positive pole of the charging input interface 210, and the first end of the first switch K1 The second end is connected to the positive pole of the charging output interface 250 , the first end of the second switch K2 is connected to the negative pole of the charging input interface 210 , and the second end of the second switch K2 is connected to the charging output The negative terminal of the interface 250 is connected.

Please refer to FIG. 3 , which is a schematic diagram of a switch module of a voltage conversion circuit provided by an embodiment of the present application. As shown in the figure, the switch module includes a first switch K1 and a second switch K2. When the circuit works in the boost mode, the first switch K1 and the second switch K2 are turned off at the same time. In the circuit mode, the first switch K1 and the second switch K2 are turned on at the same time. The first switch K1 and the second switch K2 may be a first contactor and a second contactor, respectively. Since the charging input interface 210 includes a positive input terminal and a negative input terminal, and the charging output interface also includes a negative output terminal and a positive output terminal, when the circuit works in the bypass mode, since the voltage conversion module 240 needs to be disabled, it is necessary to The voltage conversion device 240 is made to be in an open state. However, if there is only one switch in the switch module, only the positive or negative terminals of the charging input interface 210 and the charging output interface 250 can be bypassed, so that the positive or negative current on the unbypassed side will still be reduced. After passing through the filter module 220, since the positive and negative currents are not equal, a large electromagnetic field will be generated in the filter module 220 at this time, and in severe cases, the filter module 220 will be heated or even damaged.

It can be seen that in this example, the switch module also includes two switches that are respectively connected to the positive and negative poles of the charging input and output interfaces, so that when the circuit works in the bypass mode, the positive and negative poles of the filter module can be bypassed synchronously to avoid Avoid the current passing through the filter module, causing the filter module to be damaged by heat.

In a possible example, the filter module includes a first filter 221 and a second filter 222; the first end of the first filter 221 is connected to the charging input interface 210, and the first filter The second end of 221 is connected to the first end of the voltage conversion module 240; the first end of the second filter 222 is connected to the second end of the voltage conversion module 240, and the second end of the second filter 222 The second end is connected to the charging output interface 250 .

Wherein, please refer to FIG. 4, which is a schematic diagram of a filtering module of a voltage conversion circuit provided by an embodiment of the present application. As shown in the figure, a first filter 221 is connected between the charging input interface 210 and the voltage conversion module 240, and a second filter 222 is connected between the charging output interface 250 and the voltage conversion module 240, so that when the current is input and The EMI common mode interference generated when the current is output can be suppressed.

In a specific implementation, a first isolation current sensor and a first isolation voltage sensor may also be connected between the first filter 221 and the voltage conversion module 240, and the first isolation current sensor and the first isolation voltage The sensors are connected in parallel, the second filter 222 and the voltage conversion module 240 can also be connected to a second isolation current sensor and a second isolation voltage sensor, the second isolation current sensor and the second isolation voltage The sensors are connected in parallel.

It can be seen that in this example, the filtering module includes two filters, which can suppress the common mode current signal, so as to achieve the purpose of suppressing common mode interference and improve the working stability of the circuit system.

In a possible example, the first filter 221 includes a first positive coil L1 and a first negative coil L2, the second filter 222 includes a second positive coil L3 and a second negative coil L4; the first The first end of a positive coil L1 is connected to the positive electrode of the charging input interface, the second end of the first positive coil L1 is connected to the positive electrode of the first end of the voltage conversion module 240, and the first negative coil The first end of L2 is connected to the negative electrode of the charging input interface, the second end of the first negative coil L2 is connected to the negative electrode of the first end of the voltage conversion module 240 ; the second end of the second positive coil L3 One end is connected to the positive electrode of the second end of the voltage conversion module 240, the second end of the second positive coil L3 is connected to the positive electrode of the charging output interface, and the first end of the second negative coil L4 is connected to the The negative electrode of the second end of the voltage conversion module 240 is connected, and the second end of the second negative coil L4 is connected to the negative electrode of the charging output interface.

Please refer to FIG. 5 , which is a schematic diagram of a filter of a voltage conversion circuit provided by an embodiment of the present application. As shown in the figure, the V _in terminal is the charging input interface of the voltage conversion circuit, the V _out terminal is the charging output interface of the voltage conversion circuit, and K1 and K2 are the first switch and the second switch in the switch module, respectively. The filter consists of two coils, which are respectively connected to the positive and negative poles of the charging input and output interface. When the circuit works in boost mode, the current will flow through the first positive coil L1, the first negative coil L2, the second positive coil L3 and the second negative coil L4 respectively. At this time, because of the current, the The four coils will generate magnetic fields respectively, so a mutually canceling magnetic field can be generated between the first positive coil and the first negative coil, and a mutually canceling magnetic field can also be generated between the second positive coil and the second negative coil, so that the common mode current Signal is suppressed. The first filter and the second filter may be a first common mode choke coil and a second common mode choke coil.

It can be seen that in this example, the filter includes two coils connected to the charging input and output interfaces respectively, so that when the circuit works in the boost mode, a magnetic field that can cancel each other can be generated between the positive and negative electrodes, so that the common The mode current signal is suppressed, so as to suppress the EMI common mode interference and provide the working stability of the circuit system.

In a possible example, the number of turns of the first positive coil and the first negative coil are equal, and the winding directions are the same, and the number of turns of the second positive coil and the second negative coil are equal, and the windings are wound in the same direction. same direction.

Among them, as shown in FIG. 5 , when the number of turns of the first positive coil L1 and the first negative coil L2 are equal, and the winding directions are the same, the number of turns of the second positive coil L3 and the second positive coil L4 are equal, and the winding directions are the same , it means that when the currents of the positive and negative poles of the charging output interface and the charging input interface are equal, the magnetic fields generated by L1 and L2 have the same magnitude and opposite direction, and the magnetic fields generated by L3 and L4 have the same magnitude and opposite direction. The magnetic fields of the filters cancel each other out, and the magnetic core of the coil wound in the filter does not suppress the current. At this time, the filter only suppresses the common mode current signal.

It can be seen that in this example, the filter includes two coils with equal turns and the same polarity, which can suppress the common mode current signal when the circuit works in the boost mode, so as to achieve the purpose of suppressing EMI common mode interference. The working stability of the circuit system can be improved.

In a possible example, the first filter 221 includes a first main capacitor C1 and a first auxiliary capacitor C2, and the second filter 222 includes a second main capacitor C3 and a second auxiliary capacitor C4; the charging The positive pole of the input interface is combined with the first terminal of the first main capacitor C1 and then connected to the positive pole of the first terminal of the voltage conversion module 240. The second terminal of the first main capacitor C1 is connected to the first terminal of the first main capacitor C1. The second end of the auxiliary capacitor C2 is combined and grounded, and the negative electrode of the charging input interface and the first end of the first auxiliary capacitor C2 are combined and connected to the negative electrode of the first end of the voltage conversion module 240; The positive pole of the charging output interface is combined with the first terminal of the second main capacitor C3 and then connected to the positive pole of the second terminal of the voltage conversion module 240. The second terminal of the second main capacitor C3 is connected to the first terminal of the second main capacitor C3. The second terminals of the two secondary capacitors C4 are combined and grounded, and the negative terminal of the charging output interface and the first terminal of the second secondary capacitor C4 are combined and connected to the negative terminal of the second terminal of the voltage conversion module 240 .

Please refer to FIG. 6 , which is a schematic diagram of a filter of another voltage conversion circuit provided by an embodiment of the present application. As shown in the figure, the V _in terminal in the figure is the charging output interface, the V _out is the charging input interface, and K1 and K2 are the first switch and the second switch of the switch module, respectively. The interconnected ends of the main capacitor and the auxiliary capacitor are grounded, so that the current of the positive terminal and the negative terminal is changed to the line of the ground terminal, so that the common mode current signal is directly short-circuited to the ground, thereby suppressing the common mode current signal.

It can be seen that in this example, there is a main capacitor and a secondary capacitor in the filter module, so that when the circuit works in the boost mode, the common mode current signal is directly short-circuited to the ground, so that the filter can suppress the common mode current signal, so as to achieve suppression The purpose of EMI common mode interference is to improve the working stability of the circuit system.

In a possible example, the first filter 221 includes a first common mode capacitor 2210 and a first common mode inductor 2211, and the first end of the first common mode capacitor 2210 is connected to the charging input interface, so The second end of the first common mode capacitor 2210 is connected to the first end of the first common mode inductor 2211 , and the second end of the first common mode inductor 2211 is connected to the first end of the voltage conversion module 240 ; The second filter 222 includes a second common mode inductor 2220 and a second common mode capacitor 2221, the first end of the second common mode inductor 2220 is connected to the second end of the voltage conversion module 240, the The second end of the second common mode inductor 2220 is connected to the first end of the second common mode capacitor 2221, and the second end of the second common mode capacitor 2221 is connected to the charging output interface.

Wherein, as shown in FIG. 7 , FIG. 7 is a schematic diagram of a filter of another voltage conversion circuit provided by an embodiment of the present application. As shown in the figure, the first common mode inductor 2211 includes two coils, and the two coils may be the same as L1 and L2 as shown in FIG. A filter 221. The first common mode capacitor 2210 includes two capacitors, which may be the same as C1 and C2 as shown in FIG. 6 , that is, the first common mode capacitor 2210 may be the first filter 221 as shown in FIG. 6 . The second common mode inductance is the same as the second common mode capacitor, and details are not described herein again.

Therefore, the connection relationship of the voltage conversion circuit may be as follows: the first end of the first main capacitor and the first end of the first positive coil are combined and then connected to the positive electrode of the charging input interface, and the first end of the first main capacitor is connected to the positive electrode of the charging input interface. The second end of a positive coil is connected to the positive electrode of the first end of the voltage conversion module, and the first end of the first auxiliary capacitor is combined with the first end of the first negative coil and then connected to the charging input The negative terminal of the interface is connected, the second terminal of the first negative coil is connected to the negative terminal of the first terminal of the voltage conversion module, and the second terminal of the first main capacitor is connected to the second terminal of the first auxiliary capacitor. The first end of the second positive coil is connected to the positive electrode of the second end of the voltage conversion module, and the second end of the second positive coil is connected to the first end of the second main capacitor. After the circuit is connected to the positive pole of the charging output interface, the first end of the second negative coil is connected to the negative pole of the second end of the voltage conversion module, and the second end of the second negative coil is connected to the second auxiliary The second terminal of the capacitor is connected to the negative pole of the charging output interface after being combined, and the second terminal of the second main capacitor is combined with the second terminal of the second auxiliary capacitor and then grounded. Since the first positive coil and the first negative coil are wound on a ferrite magnetic ring at the same time, and the effect of the ferrite magnetic ring depends on the impedance of the original common mode loop, the lower the impedance of the original loop, Then, the effect of the ferrite magnetic ring will be more obvious, and the common mode inductor and the common mode capacitor are included in the filter module, which can reduce the impedance of the loop and make the suppression effect on the common mode current better.

It can be seen that, in this example, a common mode capacitor is connected after the common mode inductor, which can enhance the suppression effect of the filter on the common mode current signal.

Please refer to FIG. 8 , which is a schematic structural diagram of a voltage conversion device provided by an embodiment of the present application. As shown in FIG. 8 , the voltage conversion apparatus 800 may include any one of the voltage conversion circuits shown in FIGS. 2 to 7 . The voltage conversion device may be integrated in the vehicle or in the charging pile, or may be an independent device.

Please refer to FIG. 9 . FIG. 9 is a schematic structural diagram of a voltage conversion chip provided by an embodiment of the present application. As shown in FIG. 9 , the voltage conversion chip 900 may include any of the voltages shown in FIGS. 2 to 7 . conversion circuit.

Please refer to FIG. 10 . FIG. 10 is a schematic structural diagram of a charging device provided by an embodiment of the present application. As shown in FIG. 10 , the charging device 10 may include any of the voltage conversion circuits shown in FIGS. 2 to 7 . . The charging device may be a charging device located on a car, a charging device located on a charging pile, or an independent charging device.

It should be noted that, for the sake of simple description, the foregoing method embodiments are all expressed as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the described action sequence. As in accordance with the present invention, certain steps may be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

In the embodiments provided by the present invention, it should be understood that the disclosed apparatus may be implemented in other manners. For example, the device embodiments described above are only illustrative. For example, the division of the above modules is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated. to another system, or some features can be ignored, or not implemented. On the other hand, the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in electrical or other forms.

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

In addition, each functional module in each embodiment of the present invention may be integrated into one processing module, or each module may exist physically alone, or two or more modules may be integrated into one module. The above-mentioned integrated modules can be implemented in the form of hardware, and can also be implemented in the form of software function modules.

The embodiments of the present invention have been described in detail above, and the principles and implementations of the present invention are described in this paper by using specific examples. The descriptions of the above embodiments are only used to help understand the present invention and its core ideas; According to the idea of the present invention, a person of ordinary skill in the art may have changes in the specific implementation manner and application range. To sum up, the contents of this specification should not be construed as a limitation on the present invention.

Claims

A voltage conversion circuit is characterized by comprising: a charging input interface, a charging output interface, a filter module, a switch module and a voltage conversion module;

Wherein, the filtering module is used for suppressing the common mode current signal;

The switch module is configured to be turned on when the voltage value of the charging input interface is not less than a preset voltage value, and disconnected when the voltage value of the charging input interface is less than the preset voltage value, so as to realize the filtering The module works only when the voltage value of the charging input interface is not less than the preset voltage value;

The voltage conversion module is configured to convert the input voltage value of the charging input interface into the preset voltage value and output it through the charging output interface.
The circuit of claim 1, wherein the switch module comprises a first switch and a second switch;

The first end of the first switch is connected to the positive pole of the charging input interface, the second end of the first switch is connected to the positive pole of the charging output interface, and the first end of the second switch is connected to the positive pole of the charging output interface. The negative pole of the charging input interface is connected, and the second end of the second switch is connected to the negative pole of the charging output interface.
The circuit of claim 2, wherein the filter module comprises a first filter and a second filter;

The first end of the first filter is connected to the charging input interface, and the second end of the first filter is connected to the first end of the voltage conversion module;

The first end of the second filter is connected to the second end of the voltage conversion module, and the second end of the second filter is connected to the charging output interface.
The circuit of claim 3, wherein the first filter includes a first positive coil and a first negative coil, and the second filter includes a second positive coil and a second negative coil;

The first end of the first positive coil is connected to the positive electrode of the charging input interface, the second end of the first positive coil is connected to the positive electrode of the first end of the voltage conversion module, and the first negative coil The first end of the coil is connected to the negative electrode of the charging input interface, and the second end of the first negative coil is connected to the negative electrode of the first end of the voltage conversion module;

The first end of the second positive coil is connected to the positive electrode of the second end of the voltage conversion module, the second end of the second positive coil is connected to the positive electrode of the charging output interface, and the second negative coil is connected to the positive electrode of the charging output interface. The first end is connected to the negative electrode of the second end of the voltage conversion module, and the second end of the second negative coil is connected to the negative electrode of the charging output interface.
The circuit according to claim 4, wherein the first positive coil and the first negative coil have the same number of turns and the same winding direction, and the second positive coil and the second negative coil have the same number of turns. The number of turns is equal and the winding direction is the same.
The circuit of claim 3, wherein the first filter includes a first main capacitor and a first auxiliary capacitor, and the second filter includes a second main capacitor and a second auxiliary capacitor;

The positive pole of the charging input interface is combined with the first terminal of the first main capacitor and then connected to the positive pole of the first terminal of the voltage conversion module, and the second terminal of the first main capacitor is connected to the first terminal of the first main capacitor. The second end of the auxiliary capacitor is combined and grounded, and the negative electrode of the charging input interface and the first end of the first auxiliary capacitor are combined and connected to the negative electrode of the first end of the voltage conversion module;

The positive pole of the charging output interface is combined with the first terminal of the second main capacitor and then connected to the positive pole of the second terminal of the voltage conversion module, and the second terminal of the second main capacitor is connected to the second auxiliary terminal. The second end of the capacitor is combined and grounded, and the negative electrode of the charging output interface and the first end of the second auxiliary capacitor are combined and connected to the negative electrode of the second end of the voltage conversion module.
The circuit of claim 3, wherein the first filter comprises a first common mode inductor and a first common mode capacitor, and a first end of the first common mode capacitor is connected to the charging input interface , the second end of the first common mode capacitor is connected to the first end of the first common mode inductor, and the second end of the first common mode inductor is connected to the first end of the voltage conversion module;

The second filter includes a second common mode inductor and a second common mode capacitor, the first end of the second common mode inductor is connected to the second end of the voltage conversion module, and the second common mode inductor is connected to the second end of the voltage conversion module. The second end is connected to the first end of the second common mode capacitor, and the second end of the second common mode capacitor is connected to the charging output interface.
A voltage conversion device, characterized in that the voltage conversion device comprises the power conversion circuit according to any one of claims 1-7.
A voltage conversion chip, characterized in that the voltage conversion chip comprises the voltage conversion circuit according to any one of claims 1-7.
A charging device, characterized in that, the charging device includes the voltage conversion circuit according to any one of claims 1-7.