CN111049402A

CN111049402A - Alternating current-direct current conversion circuit, charging circuit and consumer

Info

Publication number: CN111049402A
Application number: CN202010011111.8A
Authority: CN
Inventors: 麻斌; 刘卫平; 陈晨; 苏逢; 李小秋
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Digital Power Technologies Co Ltd
Priority date: 2020-01-06
Filing date: 2020-01-06
Publication date: 2020-04-21

Abstract

The application discloses alternating current-direct current converting circuit, can be applied to single phase electricity, lack looks electricity or three-phase electric wire netting, a phase line inlet wire end is all connected to the first end of three switch in buffering and the combiner circuit in this circuit, the second end is connected with inductor circuit's input, bridge arm circuit's input is connected with inductor circuit's output and neutral line inlet wire end respectively, capacitor circuit is connected to bridge arm circuit's output, buffering and combiner circuit still contain at least one combiner switch, the phase line inlet wire end that a switch in this three switch is connected to every combiner switch's one end, the second end of another switch is connected to the other end. The phase line inlet wire end that a branch road corresponds is connected to combiner switch's one end among this application technical scheme, and the second end of the switch of another branch road is connected to the other end, can guarantee single-phase more than doubling when adopting single-phase electricity, can adopt the lower relay of cost simultaneously, can electrified switching when switching to lack looks or three-phase.

Description

Alternating current-direct current conversion circuit, charging circuit and consumer

Technical Field

The application relates to the technical field of alternating current-direct current conversion, in particular to an alternating current-direct current conversion circuit, a charging circuit and electric equipment.

Background

An alternating current/direct current (AC/DC) conversion circuit is a circuit that can directly convert AC electric energy into DC electric energy. In which, the power grid is commonly used with single-phase ac, three-phase ac, and phase-lacking ac lacking a live wire. The AC/DC circuit may be designed as a three-phase four-wire circuit, such as a three-phase four-wire circuit shown in fig. 1(a), in order to accommodate the above-mentioned several power grids. In the three-phase four-wire system circuit in fig. 1(a), a single-phase power is input from a/N as an example, and only one high-frequency arm (i.e., Q1Q2 arm) of the single phase operates; two high-frequency bridge arms work in the phase-failure mode; three high-frequency bridge arms work in the three phases, wherein the bridge arms from Q1 to Q6 are high-frequency bridge arms, and Q7 and Q8 are working bridge arms. The three-phase four-wire system circuit has the defect of low power when in single-phase operation.

The two ways as shown in fig. 1(b) and fig. 1(c) are adopted in the industry to solve the problem of low power during single-phase operation in the three-phase four-wire system circuit. As shown in fig. 1(B), a combination relay S4 is adopted to directly short-circuit a and B at the power grid side, and when the a-phase works in a single-phase mode, S4 is closed, so that when the a/N single-phase power is input, two high-frequency bridge arms (namely, a Q1Q2 bridge arm and a Q3Q4 bridge arm) are used for energy transfer, and the single-phase input power is doubled. However, the circuit topology in fig. 1(b) cannot perform phase-to-phase live switching, and when the voltage in the power grid is switched from single-phase to three-phase or open-phase live, the combining relay will cause direct short circuit of two phases of the power grid AB, resulting in a serious result of serious burnout of the combining relay S4. In fig. 1(c), a combined relay S4 is used, two ends of the combined relay S4 are respectively connected between the slow start relays (S1, S2) and the inductors (L1, L2) of the a and B phases, when the a phase works in a single phase, S4 is closed, so that when single-phase electricity is input from the a/N, two high-frequency bridge arms (i.e., the Q1Q2 bridge arm and the Q3Q4 bridge arm) are used for energy transfer, and thus, the single-phase input power is doubled. However, when the circuit in fig. 1(c) is operated in a single phase, S1 requires a relay having a large current capacity, which results in high cost.

Disclosure of Invention

The embodiment of the application provides an alternating current-direct current conversion circuit, can guarantee the power more than the single-phase output double, can adopt the lower relay switch of cost simultaneously, can realize electrified switching when switching to default phase or three-phase.

In order to achieve the above purpose, the embodiments of the present application provide the following technical solutions:

this application first aspect provides an alternating current-direct current conversion circuit, can be applied to single-phase electric wire netting, lack looks electric wire netting and three-phase electric wire netting, and this alternating current-direct current conversion circuit can include: the circuit comprises a first phase line incoming end, a second phase line incoming end, a third phase line incoming end, a neutral line incoming end, a buffering and combining circuit, an inductance circuit, a bridge arm circuit and a capacitance circuit, wherein the buffering and combining circuit comprises a first switch, a second switch and a third switch, and the buffering and combining circuit further comprises at least one combining switch. The first phase line inlet end, the second phase line inlet end and the third phase line inlet end can respectively correspond to A, B, C phase lines of three-phase alternating current, and the neutral line inlet end corresponds to a neutral line N of a power grid. The first end of the first switch is connected with the incoming line end of the first phase line, the second end of the first switch is connected with the input end of the inductive circuit, the first end of the second switch is connected with the incoming line end of the second phase line, the second end of the second switch is connected with the input end of the inductive circuit, the first end of the third switch is connected with the incoming line end of the third phase line, the second end of the third switch is connected with the input end of the inductive circuit, at least one of the first switch, the second switch and the third switch is connected with a slow-start resistor in parallel, the first end of the switch is connected with the first end of the slow-start resistor, the input end of the bridge arm circuit is respectively connected with the output end of the inductive circuit. The first end of each combining start end in the at least one combining switch is connected with a target incoming line end, the target incoming line end is any one of a first phase line incoming line end, a second phase line incoming line end and a third phase line incoming line end, the second end of each combining switch is connected with the second end of the target switch, the target switch is one of a first switch, a second switch and a third switch, and the phase line incoming line end connected with the first end of the target switch is different from the target incoming line end.

According to the first aspect, at least one combination switch is added between the phase line branches, one end of the combination switch is connected with the phase line inlet end of one phase line branch, the connecting point of the other end of the combination switch is located between the switch of the other phase line branch and an inductance circuit, when single-phase electricity is input, more than double power of single-phase output can be guaranteed, meanwhile, a relay with lower cost can be adopted, and live switching can be carried out when the three-phase electricity is switched to a phase failure or three-phase electricity.

Optionally, with reference to the first aspect, in a first possible implementation manner of the first aspect, the bridge arm circuit includes a first high-frequency bridge arm, a second high-frequency bridge arm, a third high-frequency bridge arm, and a power frequency bridge arm, where each of the first high-frequency bridge arm, the second high-frequency bridge arm, the third high-frequency bridge arm, and the power frequency bridge arm includes two switching tubes. The input end of each bridge arm circuit is the midpoint of each bridge arm, the output end of each bridge arm circuit is the first end and the second end of each bridge arm, and the midpoint of each bridge arm is the connection point of the two switching tubes of each bridge arm.

Optionally, with reference to the first possible implementation manner of the first aspect, in a second possible implementation manner of the first aspect, the inductive circuit includes a first inductor, a second inductor, and a third inductor, an input end of the first inductor is connected to the second end of the first switch, and an output end of the first inductor is connected to a midpoint of the first high-frequency bridge arm; the input end of the second inductor is connected with the second end of the second switch, and the output end of the second inductor is connected with the midpoint of the second high-frequency bridge arm; the input end of the third inductor is connected with the second end of the third switch, the output end of the third inductor is connected with the midpoint of the third high-frequency bridge arm, and the midpoint of the power frequency bridge arm is connected with the neutral line incoming line end.

Optionally, with reference to the first or second possible implementation manner of the first aspect, in a third possible implementation manner of the first aspect, a first end of the capacitor circuit is connected to the first end of each bridge arm, and a second end of the capacitor circuit is connected to the second end of each bridge arm.

Optionally, with reference to the first aspect and any one of the first to third possible implementation manners of the first aspect, in a fourth possible implementation manner of the first aspect, the number of the at least one combining switch is 1, the target incoming line end is a first phase incoming line end, and the target connection point is a second end of the second switch.

Optionally, with reference to the first aspect and any one of the first to the third possible implementation manners of the first aspect, in a fifth possible implementation manner of the first aspect, the number of the at least one combining switch is 1, the target incoming line end is a first phase incoming line end, and the target connection point is a second end of a third switch.

Optionally, with reference to the first aspect and any one of the first to the third possible implementation manners of the first aspect, in a sixth possible implementation manner of the first aspect, the at least one combining switch includes a first combining switch and a second combining switch, a first end of the first combining switch is connected to the first phase line incoming line end, a second end of the first combining switch is connected to the second end of the second switch, a first end of the second combining switch is connected to the first phase line incoming line end, and a second end of the first combining switch is connected to the second end of the third switch.

Optionally, with reference to the first aspect and any one of the first to sixth possible implementation manners of the first aspect, in a seventh possible implementation manner of the first aspect, the switch in the at least one combining switch is a relay or a thyristor.

Optionally, with reference to the first aspect and any one of the first to seventh possible implementation manners of the first aspect, in an eighth possible implementation manner of the first aspect, a first end of each of the first switch, the second switch, and the third switch is connected to a first end of a slow-start resistor, and a second end of each of the first switch, the second switch, and the third switch is connected to a second end of the slow-start resistor.

Optionally, with reference to the first aspect and any one of the first to eighth possible implementation manners of the first aspect, in a ninth possible implementation manner of the first aspect, the slow-start resistor is a cement resistor or a PTC thermistor.

Optionally, with reference to the ninth possible implementation manner of the first aspect, in a tenth possible implementation manner of the first aspect, a switch tube included in each of the first high-frequency bridge arm, the second high-frequency bridge arm, the third high-frequency bridge arm, and the power-frequency bridge arm is a mosfet, an igbt, or a triode.

Optionally, with reference to the first aspect and the possible implementation manners of the first to tenth aspects of the first aspect, in an eleventh possible implementation manner of the first aspect, the ac-dc converter circuit is compatible with a phase-lacking function. Phase loss refers to a loss of one or two phases of a three-phase circuit for some reason (e.g., one phase line is blown). The phase-lack function is realized by supporting that one or two lines have no current and the other two or one line have current when the three phase lines of the three-phase power grid are connected.

A second aspect of the present application provides an ac-dc converter, which is characterized by including the ac-dc conversion circuit as in the first aspect or any one of the possible implementations of the first aspect.

A third aspect of the present application provides a charging circuit, comprising: the alternating current-direct current conversion circuit is used for converting alternating current transmitted by a power grid into direct current with first voltage, and the direct current isolation circuit is connected with the alternating current-direct current conversion circuit and used for converting the direct current with the first voltage obtained by conversion of the alternating current-direct current conversion circuit into the direct current with second voltage.

The present application in a fourth aspect provides an electric device, comprising: a charging circuit and a battery. The charging circuit is used for being connected with a power grid and is connected with the battery; the charging circuit includes an ac-dc conversion circuit as described in the first aspect or any one of the possible implementations of the first aspect, and is configured to convert ac power provided by a power grid into dc power, and is further configured to charge a battery.

The embodiment of the application provides an alternating current-direct current converting circuit, through adding at least one combiner switch between the phase line branch road, the electric wire netting phase line inlet wire end of a phase line branch road is connected to the one end of this combiner switch, the tie point of the other end is located between the switch and the inductance circuit of another phase line branch road, when adopting single-phase electricity input, can guarantee the power more than the single-phase output doubling, simultaneously, can adopt the lower relay of cost, can carry out electrified switching when switching to lack looks or three-phase.

Drawings

FIG. 1(a) is a schematic diagram of a three-phase four-wire circuit;

FIG. 1(b) is a schematic diagram of another three-phase four-wire circuit;

FIG. 1(c) is a schematic diagram of another three-phase four-wire circuit configuration;

FIG. 2 is a schematic diagram of a power utilization system provided by an embodiment of the present application;

fig. 3 is a schematic structural diagram of an ac-dc conversion circuit according to an embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of another ac-dc conversion circuit provided in the embodiment of the present application;

fig. 5 is a schematic structural diagram of another ac-dc conversion circuit provided in the embodiment of the present application;

fig. 6 is a schematic structural diagram of another ac-dc conversion circuit according to an embodiment of the present application.

Detailed Description

The embodiment of the application provides an alternating current-direct current conversion circuit, can guarantee the power more than the single-phase output double, can adopt the lower relay switch of cost simultaneously, can realize electrified switching when switching to default phase or three-phase. The embodiment of the application also provides a corresponding charging circuit and electric equipment. The following are detailed below.

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In low voltage distribution networks, AC/DC circuits are designed as three-phase four-wire circuits as shown in fig. 1(a) in order to accommodate single-phase, three-phase and open-phase alternating currents commonly found in the power grid. The applicant finds that the two circuit topologies currently adopted in the industry, as shown in fig. 1(b) and fig. 1(c), for solving the problem of low operating power of a single phase in an AC/DC circuit with a three-phase four-wire system have certain defects: the circuit topology structure in fig. 1(b) has a problem that the phase-to-phase live switching cannot be performed, that is, when the voltage in the power grid is switched from single-phase to three-phase or phase-loss live, the combining relay S4 will cause a direct short circuit between the two phases AB of the power grid, and the combining relay S4 will be burned out seriously. The circuit topology in fig. 1(c) has a problem of high cost of circuit devices, that is, in the case of single-phase operation of the circuit, since S1 needs to flow all the current, a relay with large current capacity is needed, and the cost is high. Based on this, the embodiments of the present application provide an ac/dc conversion circuit, which can solve the above problems simultaneously, and will be described in detail below.

Fig. 2 is a schematic diagram of an electricity utilization system provided in the present application.

Referring to fig. 2, an electricity utilization system provided in an embodiment of the present application may include: a power grid 101 and a consumer 102. The power grid 101 is connected to the consumer 102.

The power grid 101 in the embodiment of the present application may be a single-phase alternating current power grid, a phase-lacking alternating current power grid, or a three-phase alternating current power grid. The powered device 102 in the embodiment of the present application may include a charging circuit 1021 and a battery 1022. The charging circuit 1021 is configured to convert the ac power output by the power grid 101 into dc power and charge the battery 1022. The electric equipment 102 in the embodiment of the present application may be any electric equipment connected to a power grid, such as an automobile or a communication power supply equipment. The charging circuit 1021 may be an in-vehicle charger, or may be a charging device included in a charging pile, a charging station, or a communication power supply device.

The charging circuit 1021 in the embodiment of the present application may include: an ac-dc converter circuit 10211 and a dc isolation circuit 10212. The ac/dc conversion circuit 10211 is configured to convert ac power transmitted by the power grid 101 into dc power, and the dc isolation circuit 10212 is configured to convert the high-voltage/low-voltage dc power converted by the ac/dc conversion circuit 10211 into low-voltage/high-voltage dc power for output, so as to charge the battery 1022. The DC isolation circuit 10212 in this embodiment may be a direct current-direct current (DC-DC) circuit, and a circuit structure of the DC-DC circuit may include a structure of any DC-DC circuit in the prior art, which is not described herein again.

It should be noted that the charging circuit 1021 in the embodiment of the present application may include other circuits besides the ac-dc conversion circuit 10211 and the dc isolation circuit 10212, which is not limited in the embodiment of the present application.

Based on the above-mentioned power consumption system, a specific structure of the ac/dc conversion circuit 10211 in the charging circuit 1021 in the power consumption system will be described below with reference to fig. 3.

Fig. 3 is a schematic structural diagram of an ac-dc conversion circuit according to an embodiment of the present application.

As shown in fig. 3, an ac-dc conversion circuit provided in an embodiment of the present application includes: the system comprises a first phase line inlet end A, a second phase line inlet end B, a third phase line inlet end C, a neutral line inlet end N, a buffering and combining circuit 201, an inductive circuit 202, a bridge arm circuit 203 and a capacitive circuit 204. The buffering and combining circuit 201 includes a first switch S1, a second switch S2, and a third switch S3, and the buffering and combining circuit 201 further includes at least one combining switch S4.

In the embodiment of the present application, the first phase line incoming end a, the second phase line incoming end B, and the third phase line incoming end C may respectively correspond to A, B, C three phase lines of three-phase alternating current, that is: the first phase line inlet end A, the second phase line inlet end B and the third phase line inlet end C are respectively used for connecting A, B, C three phase lines of three-phase alternating current. For example, the first phase line incoming end A corresponds to a phase line A in three-phase alternating current, the second phase line incoming end B corresponds to a phase line B in three-phase alternating current, and the second phase line incoming end C corresponds to a phase line C in three-phase alternating current. Optionally, the first phase line incoming end a may also be a phase line B corresponding to three-phase alternating current, the second phase line incoming end B corresponds to a phase line C corresponding to three-phase alternating current, and the second phase line incoming end C corresponds to the phase line a in three-phase alternating current.

In the embodiment of the present application, the first terminal of the first switch S1 is connected to the first phase line inlet terminal a, and the second terminal a of the first switch S1 is connected to the input terminal of the inductive circuit 202. A first terminal of the second switch S2 is connected to the second phase line terminal B, and a second terminal B of the second switch S2 is connected to the input terminal of the inductor circuit 202. The first terminal of the third switch S3 is connected to the third phase line terminal C, and the second terminal C of the second switch S2 is connected to the input terminal of the inductive circuit 202. In the embodiment of the present application, the output terminal and the output terminal of the inductor circuit 202 respectively mean that the current flowing from the first switch S1, the second switch S2 and/or the third switch S3 passes through the input terminal to be input into the inductor circuit 202, and then passes through the inductor circuit 202 to be output from the output terminal.

The alternating current-direct current conversion circuit in the embodiment of the application can be applied to a single-phase power grid, a three-phase power grid and a phase-lack power grid. In the embodiment of the present application, at least one of the first switch S1, the second switch S2, and the third switch S3 is connected in parallel with a slow-start resistor, and the parallel connection may be: the first end of the switch is connected with the first end of the slow-start resistor, and the second end of the switch is connected with the second end of the slow-start resistor. For example, a soft-start resistor is connected in parallel to the outside of the first switch S1, i.e., a first terminal of the first switch S1 is connected to a first terminal of the soft-start resistor, and a second terminal of the first switch S1 is connected to a second terminal of the soft-start resistor. Optionally, the second switch S2 and the third switch S2 may be connected in parallel with a soft start resistor. When the alternating current-direct current conversion circuit provided by the embodiment of the application is applied to a single-phase power grid, a slow-start resistor needs to be arranged outside a switch on a phase line branch of single-phase power input and connected with the switch in parallel. For example, when the single-phase input is an a/N input, the external part of S1 needs to be connected in parallel with a soft-start resistor, and in this case, the external part of S2 and/or S3 may or may not be connected in parallel with a soft-start resistor. When the alternating current-direct current conversion circuit is applied to a three-phase power grid, at least one switch is connected in parallel with a slow-start resistor in S1, S2 and S3. When the alternating current-direct current conversion circuit is applied to a phase-lacking power grid, at least one switch in two phase line branches of phase-lacking input is connected with a slow-starting resistor in parallel.

The input end of the bridge arm circuit 203 is respectively connected with the output end of the inductance circuit 202 and the neutral line inlet end N, and the capacitance circuit 204 is connected with the output end of the bridge arm circuit 203. In the embodiment of the present application, the inductive circuit 202 may include one or more inductors, and may also include other circuit elements in addition to the one or more inductors, the bridge arm circuit 203 may include one or more bridge arms, and may also include other circuit elements in addition to the one or more bridge arms, and the capacitive circuit 204 may include one or more capacitors, and may also include other circuit elements in addition to the one or more capacitors. In the case where the circuit can maintain a path, the present embodiment does not limit the types and the numbers of circuit elements and the connection relationship included in the inductance circuit 202, the bridge arm circuit 203, and the capacitance circuit 204.

The number of the at least one combining switch S4 included in the ac-dc conversion circuit provided in the embodiment of the present application may be one, or may be multiple. The connection position of each combining switch S4 meets the following conditions: the first end is connected with the target incoming line end, and the second end is connected with the second end of the target switch. In this embodiment, the target incoming line end connected to the first end of each combined switch S4 may be any one of a first phase line end a, a second phase line end B, and a third phase line end C, the second end of each combined switch S4 is connected to the second end of the target switch, and the target switch may be one of a first switch, a second switch, and a third switch, that is, the second end of each combined switch S4 may be any one of a second end a of the first switch, a second end B of the second switch, and a second end C of the third switch. In the embodiment of the present application, the target incoming line end and the phase incoming line end connected to the first end of the target switch are different. Taking the target incoming line end as the first incoming line end a as an example, the target switch cannot be the first switch, and may be the second switch or the third switch. Fig. 2 includes an example where the number of the combining switches S4 is 1, and shows a case of the connection position of the combining switch S4, that is, the target incoming line end connected to the first end of S4 is the first phase incoming line end a, and the second end is connected to the second end b of the second switch, and this example should not be construed as limiting the present application.

In this case, when the ac-dc converter circuit in the embodiment of the present application is applied to a single-phase power grid, assuming that a/N single-phase input is used, at this time, the total current input by the ac-dc converter circuit is the current input by the a-phase line from the first-phase line incoming end a, a slow-start resistor is connected in parallel to the outside of the first switch S1, and when the first switch S1 and the combination switch S4 are closed, half of the total current flows through each of the switches S1 and S4, so that the relays S1 and S4 may work by using low-cost relays with low current capacity, and the first high-frequency arm Q1Q2 and the second high-frequency arm Q3Q4 both flow, so as to charge the capacitor C, thereby doubling the single-phase input power. When the electrified switching from the single-phase power grid to the three-phase power grid or the open-phase power grid is carried out, the combination switch cannot be burnt due to the short circuit between the two phases, and therefore the electrified switching can be realized.

Optionally, in the ac-dc conversion circuit shown in fig. 3, the inductive circuit 202 may include three inductors L1, L2, and L3 located on different branches, the bridge arm circuit 203 may include a first high-frequency bridge arm, a second high-frequency bridge arm, a third high-frequency bridge arm, and a power-frequency bridge arm, and the inductive circuit 204 may include a capacitor C. Next, a connection mode of each circuit element in the above-described ac/dc conversion circuit will be specifically described.

Fig. 4 is a schematic structural diagram of another ac-dc conversion circuit provided in the embodiment of the present application.

As shown in fig. 4, another ac-dc conversion circuit provided in the embodiment of the present application includes: the circuit comprises a first phase line inlet end A, a second phase line inlet end B, a third phase line inlet end C, a neutral line inlet end N, a first phase line branch 10, a first phase line branch 20, a third phase line branch 30, a first high-frequency bridge arm Q1Q2, a second high-frequency bridge arm Q3Q4, a third high-frequency bridge arm Q5Q6, a power frequency bridge arm Q7Q8, a capacitor C and at least one combination switch S4.

In the embodiment of the application, the first high-frequency arm Q1Q2, the second high-frequency arm Q3Q4, the third high-frequency arm Q5Q6 and the power-frequency arm Q7Q8 all include two switching tubes. The connection point of two switching tubes Q1 and Q2 included in the first high-frequency bridge arm Q1Q2 is the midpoint of the first high-frequency bridge arm Q1Q 2; the connection point of two switching tubes Q3 and Q4 included in the second high-frequency bridge arm Q3Q4 is the midpoint of the second high-frequency bridge arm Q3Q 4; the connection point of two switching tubes Q5 and Q6 included in the third high-frequency arm Q5Q6 is the midpoint of the third high-frequency arm Q5Q 6; the connection point of the two switching tubes Q7 and Q8 contained in the power frequency bridge arm Q7Q8 is the midpoint of the power frequency bridge arm Q7Q 8. In the embodiment of the present application, the input terminals of the arm circuit 203 refer to the midpoint of the first high-frequency arm Q1Q2, the midpoint of the second high-frequency arm Q3Q4, the midpoint of the third high-frequency arm Q5Q6, and the midpoint of the power-frequency arm Q7Q 8. In the embodiment of the present application, the output end of the bridge arm circuit 203 refers to the first end and the second end of each of the first high-frequency bridge arm Q1Q2, the second high-frequency bridge arm Q3Q4, the third high-frequency bridge arm Q5Q6, and the power-frequency bridge arm Q7Q 8. Taking the first high-frequency arm Q1Q2 as an example, the second end of the switching tube Q1 is connected to the first end of the switching tube Q2, the connection point is the midpoint of the first high-frequency arm Q1Q2, and the first end and the second end of the first high-frequency arm Q1Q2 are the first end of the switching tube Q1 and the second end of the switching tube Q2, respectively.

In the embodiment of the present application, two ends of the capacitor C are respectively connected to the first end and the second end of the first high-frequency arm Q1Q2, the second high-frequency arm Q3Q4, the third high-frequency arm Q5Q6, and the power-frequency arm Q7Q 8. Specifically, a first end of the first high-frequency bridge arm Q1Q2 is connected to a first end of the capacitor C, and a second end of the capacitor C is connected to a second end of the capacitor C; a first end of the second high-frequency bridge arm Q3Q4 is connected with a first end of the capacitor C, and a second end of the second high-frequency bridge arm Q3Q4 is connected with a second end of the capacitor C; a first end of the third high-frequency bridge arm Q5Q6 is connected with a first end of the capacitor C, and a second end of the third high-frequency bridge arm Q5Q6 is connected with a second end of the capacitor C; a first end of the power frequency bridge arm Q7Q8 is connected with a first end of the capacitor C, and a second end of the power frequency bridge arm Q7Q8 is connected with a second end of the capacitor C; meanwhile, any two of the first high-frequency bridge arm Q1Q2, the second high-frequency bridge arm Q3Q4, the third high-frequency bridge arm Q5Q6 and the power-frequency bridge arm Q7Q8 are connected, wherein the first end of one bridge arm is connected with the first end of the other bridge arm, and the second end of the one bridge arm is connected with the second end of the other bridge arm. The switch tube can be a MOSFET, an IGBT or a triode.

In the embodiment of the present application, the first phase line branch 10 includes a first switch S1 and a first inductor L1, one end of the first switch S1 is connected to the first phase line incoming end a, the other end of the first switch S1 is connected to the input end of the first inductor L1 through a first connection point a, and the output end of the first inductor L1 is connected to the middle point of the first high-frequency bridge arm Q1Q 2. The second phase line branch 20 includes a second switch S2 and a second inductor L2, one end of the second switch S2 is connected to the second phase line incoming end B, the other end is connected to the input end of the second inductor L2 through a second connection point B, and the output end of the second inductor L2 is connected to the midpoint of the second high-frequency bridge arm Q3Q 4. The third phase line branch 30 includes a third switch S3 and a third inductor L3, one end of the third switch S3 is connected to the third phase line inlet C, the other end is connected to the input end of the third inductor L3 through a third connection point C, and the output end of the third inductor L3 is connected to the midpoint of the third high-frequency bridge arm Q5Q 6. And a neutral line inlet end N is connected with the middle point of the power frequency bridge arm Q7Q 8.

The alternating current-direct current conversion circuit in the embodiment of the application can be applied to a single-phase power grid, a three-phase power grid and a phase-lack power grid. In the embodiment of the present application, at least one of the first switch S1, the second switch S2, and the third switch S3 is connected in parallel with a slow-start resistor, and the parallel connection may be: one end of the switch is connected with the first end of the slow-start resistor, and the second end of the switch is connected with the other end of the slow-start resistor. For example, a soft-start resistor is connected in parallel to the outside of the first switch S1, i.e., a first terminal of the first switch S1 is connected to a first terminal of the soft-start resistor, and a second terminal of the first switch S1 is connected to a second terminal of the soft-start resistor. Alternatively, the second switch S2 and the third switch S2 may be connected in parallel with a soft start resistor in the same manner. When the alternating current-direct current conversion circuit provided by the embodiment of the application is applied to a single-phase power grid, a slow-start resistor needs to be arranged outside a switch on a phase line branch of single-phase power input and connected with the switch in parallel. For example, when the single-phase input is an a/N input, the external part of S1 needs to be connected in parallel with a soft-start resistor, and in this case, the external part of S2 and/or S3 may or may not be connected in parallel with a soft-start resistor. When the alternating current-direct current conversion circuit is applied to a three-phase power grid, at least one switch is connected in parallel with a slow-start resistor in S1, S2 and S3. When the alternating current-direct current conversion circuit is applied to a phase-lacking power grid, at least one switch in two phase line branches of phase-lacking input is connected with a slow-starting resistor in parallel.

Alternatively, in the embodiment of the present application, the switches in the first switch S1, the second switch S2, the third switch S3 and the combining switch S4 may be a relay, a metal-oxide semiconductor field-effect transistor (MOSFET), an Insulated Gate Bipolar Transistor (IGBT), and the like.

Optionally, in the embodiment of the present application, the slow-start resistor connected in parallel with the first switch S1, the second switch S2, or the third switch S3 may be a cement resistor or a thermal (PCT) resistor.

The number of the at least one combining switch S4 included in the ac-dc conversion circuit provided in the embodiment of the present application may be one, or may be multiple. The connection position of each combining switch S4 meets the following conditions: the first end is connected with the target wire inlet end, and the second end is connected with the target connecting point. In this embodiment of the application, the target incoming line end connected to the first end of each combining switch S4 and the target connection point connected to the second end do not belong to the same phase line branch, and the target incoming line end may be any one of a first phase line incoming line end a, a second phase line incoming line end B, and a third phase line incoming line end C, and the target connection point may be any one of a first connection point a, a second connection point B, and a third connection point C.

Fig. 4 illustrates a case where one combining switch S4 is included, and the connection position of the combining switch S4 is shown. The target incoming line end connected with the first end of the S4 is a first phase line end A, and the target connection point connected with the second end is a second connection point b. In this case, when the ac-dc converter circuit in the embodiment of the present application is applied to a single-phase power grid, assuming that a/N single-phase input is used, at this time, the total current input by the ac-dc converter circuit is the current input by the a-phase line from the first-phase line incoming end a, a slow-start resistor is connected in parallel to the outside of the first switch S1, and when the first switch S1 and the combination switch S4 are closed, half of the total current flows through each of the switches S1 and S4, so that the relays S1 and S4 may work by using low-cost relays with low current capacity, and the first high-frequency arm Q1Q2 and the second high-frequency arm Q3Q4 both flow, so as to charge the capacitor C, thereby doubling the single-phase input power. When the electrified switching from the single-phase power grid to the three-phase power grid or the open-phase power grid is carried out, the combination switch cannot be burnt due to the short circuit between the two phases, and therefore the electrified switching can be realized.

It should be understood that the connection position of the S4 shown in fig. 4 is only an illustration of the connection position of the combination switch S4 in the embodiment of the present application, and should not be construed as a limitation to the present application.

The alternating current-direct current converting circuit that this application embodiment provided, through add at least one combiner switch between the phase line branch road, the phase line inlet wire end that is used for a phase line branch road of electric wire netting inlet wire is connected to this combiner switch's one end, the tie point of the other end is located between the switch and the inductance of another phase line branch road, when adopting single-phase electricity, can guarantee to go out the power more than doubly single-phase, and simultaneously, can adopt the lower relay of cost, can carry out electrified switching when switching to default phase or three-phase.

Fig. 4 shows a case where the ac-dc conversion circuit includes only one combining switch S4, and when the ac-dc conversion circuit in the embodiment of the present application includes only one combining switch S4, the structure of the ac-dc conversion circuit can be understood with reference to fig. 5.

Fig. 5 is a schematic structural diagram of another ac-dc conversion circuit according to an embodiment of the present application.

The ac/dc conversion circuit shown in fig. 5 includes: the device comprises a first phase line inlet end A, a second phase line inlet end B, a third phase line inlet end C, a neutral line inlet end N, a first phase line branch 10, a first phase line branch 20, a third phase line branch 30, a first high-frequency bridge arm Q1Q2, a second high-frequency bridge arm Q3Q4, a third high-frequency bridge arm Q5Q6, a power frequency bridge arm Q7Q8, a capacitor C and a combination switch S4.

In the embodiment of the present application, the connection modes of the first phase line incoming end a, the second phase line incoming end B, the third phase line incoming end C, the neutral line incoming end N, the first phase line branch 10, the first phase line branch 20, the third phase line branch 30, the first high-frequency arm Q1Q2, the second high-frequency arm Q3Q4, the third high-frequency arm Q5Q6, the power frequency arm Q7Q8, and the capacitor C, and the positions of the first connection point a, the second connection point B, and the third connection point C may be understood with reference to fig. 4, and are not described herein again.

In the embodiment of the present application, at least one of the first switch S1, the second switch S2, and the third switch S3 is connected in parallel with a soft start resistor, and the parallel connection may be: one end of the switch is connected with the first end of the slow-rising resistor, and the second end of the switch is connected with the other end of the slow-rising resistor. For example, a soft-start resistor is connected in parallel to the outside of the first switch S1, i.e., a first terminal of the first switch S1 is connected to a first terminal of the soft-start resistor, and a second terminal of the first switch S1 is connected to a second terminal of the soft-start resistor. Alternatively, the second switch S2 and the third switch S2 may be connected in parallel with a soft start resistor in the same manner. When the alternating current-direct current conversion circuit provided by the embodiment of the application is applied to a single-phase power grid, a slow-start resistor needs to be arranged outside a switch on a phase line branch of single-phase power input and connected with the switch in parallel. For example, when the single-phase input is an a/N input, the external part of S1 needs to be connected in parallel with a soft-start resistor, and in this case, the external parts of S2 and/or S3 may or may not need to be connected in parallel with a soft-start resistor. When the alternating current-direct current conversion circuit is applied to a three-phase power grid, at least one switch is connected in parallel with a slow-start resistor in S1, S2 and S3. When the alternating current-direct current conversion circuit is applied to a phase-lacking power grid, at least one switch in two phase line branches of phase-lacking input is connected with a slow-starting resistor in parallel. Fig. 5 shows a case where each of the first switch S1, the second switch S2, and the third switch S3 has a soft-start resistor connected in parallel therewith, wherein the first switch S1 is connected in parallel with the soft-start resistor R1, the second switch S2 is connected in parallel with the soft-start resistor R2, and the third switch S3 is connected in parallel with the soft-start resistor R3. The slow-start resistors R1, R2, and R3 may be cement resistors or PTC thermistors.

The ac-dc conversion circuit in the embodiment of the present application includes a combining switch S4. The alternating current-direct current conversion circuit in the embodiment of the application can be applied to a single-phase power grid, a phase-lack power grid and a three-phase power grid. When the ac-dc conversion circuit in the embodiment of the present application is applied to a single-phase power grid, taking a/N single-phase input as an example, a total current input by the ac-dc conversion circuit is a current input by an a-phase line from a first-phase-line incoming end a, a target incoming end connected to one end of the combining switch S4 is the first-phase-line incoming end a, and a target connection point at the other end may be a third connection point c. When the first switch S1 and the combination switch S4 are closed, half of the total current flows from each of S1 and S4, and the first high-frequency arm Q1Q2 and the second high-frequency arm Q3Q4 both flow, so that the double of the single-phase input power can be realized in the process of charging the capacitor C, and the relays with low cost and low current capacity can be selected for the S1 and the S4 to work. When the single-phase or open-phase power grid input is required to be switched, the combination switch S4 is not burnt due to short circuit between two phases, and therefore live-line switching can be carried out.

It should be noted that, when the single-phase input is B/N input, the target incoming line end connected to one end of the combining switch S4 is the first phase incoming line end B, and the target connection point at the other end may be the first connection point a or the third connection point c. When the single-phase input is C/N input, the target incoming line end connected to one end of the combining switch S4 is the third-phase incoming line end C, and the target connection point at the other end may be the first connection point a or the second connection point b.

In the above description, the case that the ac-dc conversion circuit provided by the present application only includes one combining switch S4 is described, and when the ac-dc conversion circuit in the embodiment of the present application includes two combining switches, the structure of the ac-dc conversion circuit can be understood with reference to fig. 6.

The ac/dc conversion circuit shown in fig. 6 includes: the device comprises a first phase line inlet end A, a second phase line inlet end B, a third phase line inlet end C, a neutral line inlet end N, a first phase line branch 10, a first phase line branch 20, a third phase line branch 30, a first high-frequency bridge arm Q1Q2, a second high-frequency bridge arm Q3Q4, a third high-frequency bridge arm Q5Q6, a power frequency bridge arm Q7Q8, a capacitor C and a combination switch S4.

In the embodiment of the present application, a first phase line incoming end a, a second phase line incoming end B, a third phase line incoming end C, a neutral line incoming end N, a first phase line branch 10, a first phase line branch 20, a third phase line branch 30, a first high-frequency bridge arm Q1Q2, a second high-frequency bridge arm Q3Q4, a third high-frequency bridge arm Q5Q6, a power frequency bridge arm Q7Q8, and a connection manner of a capacitor C, as well as a first connection point a, a second connection point B, and a third connection point C may be understood with reference to fig. 4, and are not described herein again.

In the embodiment of the present application, at least one of the first switch S1, the second switch S2, and the third switch S3 is connected in parallel with a soft start resistor, and the parallel connection may be: the first end of the switch is connected with the first end of a slow-start resistor, and the second end of the switch is connected with the other end of the slow-start resistor. For example, a soft-start resistor is connected in parallel to the outside of the first switch S1, i.e., a first terminal of the first switch S1 is connected to a first terminal of the soft-start resistor, and a second terminal of the first switch S1 is connected to a second terminal of the soft-start resistor. Alternatively, the second switch S2 and the third switch S2 may be connected in parallel with a soft start resistor in the same manner. When the alternating current-direct current conversion circuit provided by the embodiment of the application is applied to a single-phase power grid, a slow-start resistor needs to be arranged outside a switch on a phase line branch of single-phase power input and connected with the switch in parallel. For example, when the single-phase input is an a/N input, the external part of S1 needs to be connected in parallel with a soft-start resistor, and in this case, the external part of S2 and/or S3 may or may not be connected in parallel with a soft-start resistor. When the alternating current-direct current conversion circuit is applied to a three-phase power grid, at least one switch is connected in parallel with a slow-start resistor in S1, S2 and S3. When the alternating current-direct current conversion circuit is applied to a phase-lacking power grid, at least one switch in two phase line branches of phase-lacking input is connected with a slow-starting resistor in parallel. Fig. 6 shows a case where each of the first switch S1, the second switch S2, and the third switch S3 has a soft-start resistor connected in parallel therewith, wherein the first switch S1 is connected in parallel with the soft-start resistor R1, the second switch S2 is connected in parallel with the soft-start resistor R2, and the third switch S3 is connected in parallel with the soft-start resistor R3. The slow-start resistors R1, R2, and R3 may be cement resistors or PTC thermistors.

The ac-dc conversion circuit in this embodiment of the application includes two combiner switches, which are the first combiner switch S41 and the second combiner switch S42, respectively. The alternating current-direct current conversion circuit in the embodiment of the application can be applied to a single-phase power grid, a phase-lack power grid and a three-phase power grid. When the ac-dc conversion circuit in this embodiment of the application is applied to a single-phase power grid, taking an a/N single-phase input as an example, the target incoming line ends connected to one ends of the first combination switch S41 and the second combination switch S42 are both a first phase line incoming line end a, where the target connection point at the other end of the first combination switch S41 is a second connection point b, and the target connection point at the other end of the first combination switch S42 is a third connection point c. When the ac-dc conversion circuit in the embodiment of the present application is applied to an a/N single-phase input power grid, at this time, the total current input by the ac-dc conversion circuit is the current input by the a-phase line from the first-phase line incoming end a, and when the first switch S1, the first combination switch S41, and the second combination switch S42 are all closed, the current will flow through one third of the total current from each of S1, S41, and S42, so S1, S41, and S42 may all use a low-cost relay to work, and the first high-frequency bridge arm Q1Q2, the second high-frequency bridge arm Q3Q4, and the third high-frequency bridge arm Q5Q6 all flow through, so as to charge the capacitor C, and thereby can realize three times of increase of single-phase input power. When switching from single-phase to three-phase or open-phase input is performed, the combination switch S41 or S42 is not burned due to a short circuit between two phases, and thus live switching can be achieved.

When the single-phase input is B/N input, the target incoming line end connected to one end of the combining switches S41 and S42 may be the first phase incoming line end B, the target connection point at the other end of the first combining switch S41 is the first connection point a, and the target connection point at the other end of the first combining switch S42 is the third connection point c. When the single-phase input is C/N input, the target incoming line end connected to one end of the combining switches S41 and S42 may be the first phase incoming line end C, the target connection point at the other end of the first combining switch S41 is the first connection point a, and the target connection point at the other end of the first combining switch S42 is the second connection point b.

Optionally, in this embodiment of the application, the combining switches S41 and S42 may further include other connection manners, for example, one end of S41 is connected to the first phase input terminal a, and the other end is connected to the second connection point B, in this case, one end of S42 is connected to the second phase input terminal B, and the other end is connected to the third connection point C or the first connection point a, or one end of S42 is connected to the third phase input terminal C, and the other end is connected to the first connection point a or the second connection point B, and so on.

Above, introduce the alternating current-direct current converting circuit that this application provided, the alternating current-direct current converting circuit that this application provided can guarantee single-phase out the power more than doubly when adopting single-phase electricity, can adopt the lower relay of cost simultaneously, can realize electrified switching when switching to lack looks or three-phase.

The embodiment of the present application further provides an ac-dc converter, which includes the ac-dc conversion circuit described in fig. 3 to fig. 6, and the ac-dc converter may further include a circuit with another structure connected to the ac-dc conversion circuit.

In the present application, "at least one" means one or more, "a plurality" means two or more. "and/or" describes the association relationship of the associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone, wherein A and B can be singular or plural. In the embodiments of the present application, unless otherwise specified or conflicting with respect to logic, the terms and/or descriptions in different embodiments have consistency and may be mutually cited, and technical features in different embodiments may be combined to form a new embodiment according to their inherent logic relationship. It is to be understood that the various numerical references referred to in the embodiments of the present application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of the present application.

The ac-dc conversion circuit, the charging circuit, and the electric device provided in the embodiments of the present application are described in detail above, and a specific example is applied in the present application to explain the principle and the implementation manner of the present application, and the description of the above embodiments is only used to help understand the method and the core idea of the present application; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

Claims

1. An ac-dc converter circuit, comprising: a first phase line inlet end, a second phase line inlet end, a third phase line inlet end, a neutral line inlet end, a buffering and combining circuit, an inductance circuit, a bridge arm circuit and a capacitance circuit, wherein the buffering and combining circuit comprises a first switch, a second switch and a third switch, the buffering and combining circuit further comprises at least one combining switch,

the first end of the first switch is connected with the incoming line end of the first phase line, the second end of the first switch is connected with the input end of the inductive circuit, the first end of the second switch is connected with the incoming line end of the second phase line, the second end of the second switch is connected with the input end of the inductive circuit, the first end of the third switch is connected with the incoming line end of the third phase line, the second end of the third switch is connected with the input end of the inductive circuit, at least one of the first switch, the second switch and the third switch is connected with a slow-start resistor in parallel, the first end of one switch is connected with the first end of the slow-start resistor, the second end of the switch is connected with the second end of the slow-start resistor, the input end of the bridge arm circuit is respectively connected with the output end of the inductive circuit and the incoming line end of the neutral line, and;

the first end of each combination switch is connected with a target incoming line end, and the target incoming line end is any one of the first phase line incoming line end, the second phase line incoming line end and the third phase line incoming line end; the second end of each combiner switch is connected with the second end of a target switch, the target switch is one of the first switch, the second switch and the third switch, and a phase line incoming line end connected with the first end of the target switch is different from the target incoming line end.

2. The AC-DC converter circuit according to claim 1, wherein said bridge arm circuit comprises a first high frequency bridge arm, a second high frequency bridge arm, a third high frequency bridge arm, and a power frequency bridge arm, each of said first high frequency bridge arm, said second high frequency bridge arm, said third high frequency bridge arm, and said power frequency bridge arm comprising two switching tubes,

the input end of each bridge arm circuit is the midpoint of each bridge arm, the output end of each bridge arm circuit is the first end and the second end of each bridge arm, and the midpoint of each bridge arm is the connection point of the two switching tubes of each bridge arm.

3. The AC-DC converter circuit of claim 2, wherein said inductor circuit comprises a first inductor, a second inductor, and a third inductor,

the input end of the first inductor is connected with the second end of the first switch, and the output end of the first inductor is connected with the midpoint of the first high-frequency bridge arm; the input end of the second inductor is connected with the second end of the second switch, and the output end of the second inductor is connected with the midpoint of the second high-frequency bridge arm; the input end of the third inductor is connected with the second end of the third switch, the output end of the third inductor is connected with the midpoint of the third high-frequency bridge arm, and the midpoint of the power-frequency bridge arm is connected with the neutral line incoming line end.

4. The AC-DC converter circuit according to claim 2 or claim 3, wherein the first end of the capacitor circuit is connected to the first end of each of the legs, and the second end of the capacitor circuit is connected to the second end of each of the legs.

5. The AC-DC conversion circuit according to any one of claims 1-4, wherein the number of said at least one combining switch is 1, said target incoming line terminal is said first phase incoming line terminal, and said target switch is said second switch.

6. The AC-DC conversion circuit according to any one of claims 1-4, wherein the number of said at least one combining switch is 1, said target incoming line terminal is said first phase incoming line terminal, and said target switch is said third switch.

7. The ac-dc converter circuit according to any of claims 1-4, wherein said at least one combining switch comprises a first combining switch and a second combining switch, a first end of said first combining switch is connected to said first phase line inlet, a second end of said first combining switch is connected to a second end of said second switch, a first end of said second combining switch is connected to said first phase line inlet, and a second end of said first combining switch is connected to a second end of said third switch.

8. The ac-dc converter circuit according to any of claims 1-7, wherein the switch of said at least one combiner switch is a relay or a thyristor.

9. The ac-dc converter circuit according to any of claims 1-8, wherein a first terminal of each of said first switch, said second switch and said third switch is connected to a first terminal of a soft-start resistor, and a second terminal is connected to a second terminal of said soft-start resistor.

10. The ac-dc converter circuit according to any of claims 1-9, wherein said slow-start resistor is a cement resistor or a PTC thermistor.

11. The ac-dc converter circuit according to any of claims 2-10, wherein said switching device is a mosfet, an igbt or a triode.

12. The ac-dc converter circuit according to any of claims 1-11, wherein said ac-dc converter circuit is compatible with open-phase functionality.

13. A converter according to any of claims 1-12, characterized in that it comprises a converter circuit according to any of claims 1-12.

14. A charging circuit, comprising: an AC-DC conversion circuit and a DC isolation circuit,

the ac-dc converter circuit according to any of claims 1-12 for converting an ac power transmitted by a power grid into a dc power of a first voltage,

the direct current isolation circuit is connected with the alternating current-direct current conversion circuit and used for converting the direct current of the first voltage obtained by conversion of the alternating current-direct current conversion circuit into the direct current of the second voltage.

15. An electrical device, comprising: a charging circuit and a battery; the charging circuit is used for being connected with a power grid;

the charging circuit is connected with the battery;

the charging circuit comprising the ac-dc converter circuit according to any of claims 1-12 for converting ac power provided by the grid into dc power, and for charging the battery.