WO2022077262A1

WO2022077262A1 - Bidirectional resonant circuit and automobile

Info

Publication number: WO2022077262A1
Application number: PCT/CN2020/120880
Authority: WO
Inventors: 陈晓斌; 张辉; 宋安国; 吴壬华
Original assignee: 深圳欣锐科技股份有限公司
Priority date: 2020-10-14
Filing date: 2020-10-14
Publication date: 2022-04-21
Also published as: CN113424426A; CN113424426B

Abstract

A bidirectional resonant circuit and an automobile. The circuit comprises a first bridge circuit, a transformer, a resonant circuit and a second bridge circuit, wherein the first bridge circuit is connected to a secondary winding of the transformer, one end of the resonant circuit is connected to a primary winding of the transformer, and the other end of the resonant circuit is connected to the second bridge circuit. When the bidirectional resonant circuit is in a reverse operating state, within a set period, a controllable switch tube of the first bridge circuit is turned on with a fixed duty cycle, and a controllable switch tube of the second bridge circuit is turned on with an adjustable duty cycle. Without adding components, in the reverse operating state and on the basis of controlling the turning on of the first bridge circuit, the controllable switch tube, connected to a high-voltage battery, of the second bridge circuit is controlled to be turned on, so as to increase a voltage range during the reverse operation. The number of components of a product is reduced, such that the product volume is reduced, and accordingly, the costs are reduced, and the loss of the circuit itself is also reduced.

Description

Bidirectional Resonant Circuits and Automotive

technical field

The present application relates to the field of electrical technology, and in particular, to a bidirectional resonant circuit and an automobile.

Background technique

With the development of new energy vehicles, the development of their power supply systems has become more and more mature, and the application of direct current-direct current (DC-DC) converters is also relatively common. With the increasing demand for on-board power functions, bidirectional DC-DC converters have emerged. When the bidirectional DC-DC converter works in the forward direction, it can convert the electricity of the high-voltage battery into low-voltage direct current, and charge the high-voltage direct current to the low-voltage battery; when the bidirectional DC-DC converter works in the reverse direction, it can convert the electricity of the low-voltage battery into high voltage Direct current to charge the low voltage direct current to the high voltage battery.

In the process of actually using a bidirectional DC-DC converter, sometimes the voltage range of reverse operation is required to be higher. In order to achieve this purpose, an inductor and a capacitor are generally connected in series on the secondary circuit, or a capacitor is connected in series on the secondary circuit. Both of the above two schemes can improve the voltage range of reverse operation, but both add components to the secondary side circuit, which leads to an increase in the number and volume of components and an increase in cost; on the other hand, during reverse operation, the current of the secondary side circuit increases. Larger, adding components will greatly increase the current consumption.

SUMMARY OF THE INVENTION

The purpose of the present application is to provide a bidirectional resonant circuit and an automobile, so as to solve the above problems, and to improve the voltage range of reverse operation without adding components on the secondary side.

A first aspect of the present application provides a bidirectional resonant circuit, including a first bridge circuit, a transformer, a resonant circuit, and a second bridge circuit; the first bridge circuit is connected to a secondary winding of the transformer, and the resonant circuit is connected to the secondary winding of the transformer. One end of the circuit is connected to the primary winding of the transformer, and the other end of the resonant circuit is connected to the second bridge circuit; when the bidirectional resonant circuit is in a reverse working state, within a set period, the The controllable switch tube of the first bridge circuit is turned on with a fixed duty cycle, and the controllable switch tube of the second bridge circuit is turned on with an adjustable duty cycle; the first bridge circuit is used to connect the low voltage The direct current is converted into alternating current and transmitted to the transformer; the transformer is used to transmit the alternating current to the resonant circuit in the form of an alternating magnetic field; the resonant circuit is used to resonate the alternating current, and transmit the resonated alternating current to the resonant circuit. the second bridge circuit; the second bridge circuit is used to rectify the alternating current into high voltage direct current.

In the above bidirectional resonant circuit, wherein the fixed duty cycle is 0.5, and the adjustable duty cycle range is: 0<adjustable duty cycle≤0.5.

In the above-mentioned bidirectional resonant circuit, some or all of the controllable switch tubes of the second bridge circuit are turned on with an adjustable duty cycle.

The above bidirectional resonant circuit, wherein the first bridge circuit includes a half-bridge circuit, and the half-bridge circuit includes a first controllable switch tube and a second controllable switch tube; the first controllable switch tube and the second controllable switch tube complementarily conduct with the fixed duty cycle;

The second bridge circuit includes a first full-bridge circuit, and the first full-bridge circuit includes a third controllable switch, a fourth controllable switch, a fifth controllable switch and a sixth controllable switch; The third controllable switch tube and the fourth controllable switch tube are located in the same half bridge, and the fifth controllable switch tube and the sixth controllable switch tube are located in the same half bridge; During the conduction period of the control switch tube, the third controllable switch tube and the fifth controllable switch tube start conduction after a set period of time; during the conduction period of the second controllable switch tube , the third controllable switch tube and the fifth controllable switch tube are synchronously turned on after a delay of a set time period; the fourth controllable switch tube and the sixth controllable switch tube are not turned on.

The above bidirectional resonant circuit, wherein the first bridge circuit includes a half-bridge circuit, and the half-bridge circuit includes a first controllable switch tube and a second controllable switch tube; the first controllable switch tube and the second controllable switch in complementary conduction with the fixed duty cycle; the second bridge circuit includes a first full-bridge circuit, the first full-bridge circuit includes a third controllable switch, a third Four controllable switch transistors, fifth controllable switch transistor and sixth controllable switch transistor; the third controllable switch transistor and the fourth controllable switch transistor are located in the same half bridge, and the fifth controllable switch transistor and the sixth controllable switch tube are located in the same half-bridge; during the conduction period of the first controllable switch tube, the third controllable switch tube and the fifth controllable switch tube are set later The time period starts to conduct; in the conduction period of the second controllable switch tube, the fourth controllable switch tube and the sixth controllable switch tube are synchronously turned on after a delay of a set time period.

The bidirectional resonant circuit as described above, wherein the first bridge circuit includes a second full-bridge circuit, and the second full-bridge circuit includes a seventh controllable switch, an eighth controllable switch, and a ninth controllable switch. The switch tube and the tenth controllable switch tube; the seventh controllable switch tube and the eighth controllable switch tube are located in the same half bridge, and the ninth controllable switch tube and the tenth controllable switch tube are located at The same half-bridge; the seventh controllable switch and the eighth controllable switch are complementarily turned on at a fixed duty ratio, and the ninth controllable switch and the tenth controllable switch are at a fixed duty The duty ratio is complementarily turned on; the seventh controllable switch tube and the tenth controllable switch tube are turned on synchronously, and the eighth controllable switch tube and the ninth controllable switch tube are turned on synchronously; the The second bridge circuit includes a first full-bridge circuit, and the first full-bridge circuit includes a third controllable switch, a fourth controllable switch, a fifth controllable switch, and a sixth controllable switch; the The third controllable switch tube and the fourth controllable switch tube are located in the same half bridge, and the fifth controllable switch tube and the sixth controllable switch tube are located in the same half bridge; in the seventh controllable switch tube During the conduction period of the eighth controllable switch tube, the third controllable switch tube and the fifth controllable switch tube start conduction after a set period of time; during the conduction period of the eighth controllable switch tube, all The third controllable switch tube and the fifth controllable switch tube are synchronously turned on after a delay of a set time period; the fourth controllable switch tube and the sixth controllable switch tube are not turned on.

The bidirectional resonant circuit as described above, wherein the first bridge circuit includes a second full-bridge circuit, and the second full-bridge circuit includes a seventh controllable switch, an eighth controllable switch, and a ninth controllable switch. The switch tube and the tenth controllable switch tube; the seventh controllable switch tube and the eighth controllable switch tube are located in the same half bridge, and the ninth controllable switch tube and the tenth controllable switch tube are located at The same half-bridge; the seventh controllable switch and the eighth controllable switch are complementarily turned on at a fixed duty ratio, and the ninth controllable switch and the tenth controllable switch are at a fixed duty The duty ratio is complementarily turned on; the seventh controllable switch tube and the tenth controllable switch tube are turned on synchronously, and the eighth controllable switch tube and the ninth controllable switch tube are turned on synchronously; the The second bridge circuit includes a first full-bridge circuit, and the first full-bridge circuit includes a third controllable switch, a fourth controllable switch, a fifth controllable switch, and a sixth controllable switch; the The third controllable switch tube and the fourth controllable switch tube are located in the same half bridge, and the fifth controllable switch tube and the sixth controllable switch tube are located in the same half bridge; in the seventh controllable switch tube During the conduction period of the eighth controllable switch tube, the third controllable switch tube and the fifth controllable switch tube start conduction after a set period of time; during the conduction period of the eighth controllable switch tube, all The fourth controllable switch tube and the sixth controllable switch tube are synchronously turned on after being delayed by a set time period.

The bidirectional resonant circuit as described above, wherein the resonant circuit includes an inductor and a capacitor, the first end of the capacitor is connected to the first end of the primary winding of the transformer, and the second end of the capacitor is connected to the first end node connection; the first connection node is located between the third controllable switch tube and the fourth controllable switch tube; the first end of the inductor is connected to the second end of the primary winding of the transformer, The second end of the inductor is connected to a second connection node; the second connection node is located between the fifth controllable switch tube and the sixth controllable switch tube.

The bidirectional resonant circuit as described above, wherein, when the bidirectional resonant circuit is in a forward working state, within a set period, the controllable switch tube of the second bridge circuit uses the The fixed duty cycle is turned on, and the controllable switch tube of the first bridge circuit is not turned on; the second bridge circuit is used to invert high-voltage direct current into alternating current and transmit it to the resonant circuit; the resonant circuit used to resonate the alternating current, and transmit the resonated alternating current to the transformer; the transformer is used to transmit the alternating current to the first bridge circuit in the form of an alternating magnetic field; the first bridge circuit is used for Rectify alternating current to low voltage direct current.

A second aspect of the present application provides an automobile, including an on-board power supply system, wherein the on-board power supply system includes the bidirectional resonant circuit described in any one of the first aspect of the present application.

In the bidirectional resonant line provided by the present application, without adding components, in the reverse working state, on the basis of controlling the conduction of the first bridge circuit, the controllable switch tube of the second bridge circuit connected to the high-voltage battery is controlled to conduct conduction. to increase the voltage range during reverse operation. The number of components of the product is reduced, so the volume of the product is reduced, correspondingly, the cost is reduced, and the loss of the circuit itself is also reduced.

Description of drawings

In order to describe the technical solutions in the embodiments of the present invention more clearly, the accompanying drawings required in the embodiments will be briefly introduced below.

In order to illustrate the technical solutions of the present application more clearly, the following briefly introduces the accompanying drawings used in the implementation manner. Obviously, the accompanying drawings in the following description are only some implementations of the present application, which are common in the art. As far as technical personnel are concerned, other drawings can also be obtained from these drawings without creative labor.

1 is a circuit diagram of a bidirectional resonant circuit provided by an embodiment of the present application;

2 is a schematic diagram of a periodic signal of a bidirectional resonant circuit working in the forward direction provided by an embodiment of the present application;

3 is a schematic diagram of a periodic signal when a bidirectional resonant circuit provided in an embodiment of the present application works in reverse;

4 is a schematic diagram of another periodic signal when a bidirectional resonant circuit according to an embodiment of the present application works in reverse;

5 is a circuit diagram of another bidirectional resonant circuit provided by an embodiment of the present application;

FIG. 6 is a schematic diagram of a periodic signal of another bidirectional resonant circuit operating in the forward direction provided by an embodiment of the present application;

7 is a schematic diagram of a periodic signal when another bidirectional resonant circuit provided in an embodiment of the present application works in reverse;

FIG. 8 is a schematic diagram of another periodic signal when another bidirectional resonant circuit according to an embodiment of the present application works in reverse.

Detailed ways

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. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

The bidirectional resonant circuit provided by the embodiments of the present application includes a first bridge circuit, a transformer, a resonant circuit, and a second bridge circuit; the first bridge circuit is connected to the secondary winding of the transformer, and the resonant circuit is One end is connected to the primary winding of the transformer, and the other end of the resonant circuit is connected to the second bridge circuit.

When the bidirectional resonant circuit is in a reverse working state, within a set period, the controllable switch tube of the first bridge circuit is turned on with a fixed duty cycle, and the controllable switch of the second bridge circuit is turned on. The tube is turned on with an adjustable duty cycle.

The first bridge circuit is used to invert low-voltage direct current into alternating current and transmit it to the transformer; the transformer is used to transmit the alternating current to the resonant circuit in the form of an alternating magnetic field; the resonant circuit is used to convert the alternating current. Resonance is performed, and the resonated alternating current is transmitted to the second bridge circuit; the second bridge circuit is used to rectify the alternating current into high-voltage direct current.

The controllable switch tube involved in the present application may be a metal-oxide-semiconductor (metal-oxide-semiconductor, MOS) field effect transistor.

In the bidirectional resonant circuit in this embodiment, the first bridge circuit is connected to a low-voltage DC power supply, and the second bridge circuit is connected to a high-voltage DC power supply or a device requiring high-voltage power supply. For the convenience of description, it is taken as an example that the second bridge circuit is connected to the high-voltage DC power supply. The low-voltage DC power supply illustrated in FIG. 1 is a rechargeable low-voltage battery, and the high-voltage DC power supply illustrated in FIG. 1 is a rechargeable high-voltage battery.

In this embodiment, without adding components, in the reverse working state, on the basis of controlling the conduction of the first bridge circuit, the controllable switch tube of the second bridge circuit connected to the high-voltage battery is controlled to be turned on. When the controllable switch tube of the second bridge circuit is turned on, the second bridge circuit forms a short circuit, and the second bridge circuit has a large current at this time. In the case of the on state, the above-mentioned large current can be supplied to devices that require high-voltage power supply, thereby increasing the voltage range during reverse operation. The number of components of the product is reduced, so the volume of the product is reduced, correspondingly, the cost is reduced, and the loss of the circuit itself is also reduced.

Further, the fixed duty cycle in this embodiment may be 0.5, and the adjustable duty cycle range is: 0<adjustable duty cycle≤0.5. By setting the adjustable duty cycle between 0 and 0.5, various voltage ranges for reverse operation can be achieved, and the larger the adjustable duty cycle is, the wider the voltage range of reverse operation is, and its applicability is stronger.

It can be understood that the above-mentioned resonant circuit includes an inductance and a capacitance, and the setting period of the bidirectional resonant circuit is determined according to the inductance and capacitance. Specifically, the set period of the bidirectional resonant circuit is calculated according to the following formula:

Ts is the set period, L1 is the inductance of the inductor, and C1 is the capacitance of the capacitor.

The composition of the bidirectional resonant circuit in this embodiment will be described below. In this embodiment, the composition of the bidirectional resonant circuit has two specific implementations, one of which is that the first bridge circuit is a half-bridge circuit (as shown in FIG. 1 ), The second bridge circuit is a full bridge circuit; the other is that the first bridge circuit and the second bridge circuit are both full bridge circuits (as shown in Figure 5), as detailed below:

first embodiment

Referring to FIG. 1 , in this embodiment, the bidirectional resonant circuit includes a low-voltage battery, a first bridge circuit, a transformer T, a resonant circuit, a second bridge circuit and a high-voltage battery. The first bridge circuit is a half bridge circuit, and the second bridge circuit is a first full bridge circuit.

Specifically, the half-bridge circuit includes a first controllable switch S1 and a second controllable switch S2. The transformer T includes a primary winding and a secondary winding. The resonant circuit includes a capacitor C and an inductor L. The first full-bridge circuit includes a third controllable switch S3, a fourth controllable switch S4, a fifth controllable switch S5 and a sixth controllable switch S6; the third controllable switch S3 and The fourth controllable switch S4 is located in the same half bridge, and the fifth controllable switch S5 and the sixth controllable switch S6 are located in the same half bridge.

One end of the first controllable switch tube S1 is connected to the negative electrode of the low-voltage battery, the other end of the first controllable switch tube S1 is connected to one end of the primary winding; the other end of the primary winding is connected to one end of the second controllable switch tube S2, The other end of the second controllable switch tube S2 is connected to the negative electrode of the low-voltage battery; the middle part of the primary winding is connected to the positive electrode of the low-voltage battery.

One end of the capacitor C is connected to one end of the primary winding, and the other end of the primary winding is connected to one end of the inductor L. The other end of the capacitor C is connected to the first connection node, and the other end of the inductor L is connected to the second connection node. The first connection node is set between the third controllable switch tube S3 and the fourth controllable switch tube S4, and the second connection node is set between the fifth controllable switch tube S5 and the sixth controllable switch tube S6. The third controllable switch S3 and the fourth controllable switch S4 form a half bridge. In the half bridge, the third controllable switch S3 is connected to the positive pole of the high-voltage battery, and the fourth controllable switch S4 is connected to the positive pole of the high-voltage battery. Negative connection. The fifth controllable switch tube S5 and the sixth controllable switch tube S6 form a half bridge. In the half bridge, the fifth controllable switch tube S5 is connected to the positive pole of the high-voltage battery, and the sixth controllable switch tube S6 is connected to the positive pole of the high-voltage battery. Negative connection.

The following describes the bidirectional resonant circuit of the first embodiment, and the control method during forward operation:

When working in the forward direction, the second bridge circuit is used to convert the high-voltage direct current provided by the high-voltage battery into alternating current and transmit it to the resonant circuit; the resonant circuit is used to resonate the alternating current and transmit the resonated alternating current. to the transformer T; the transformer T is used to transmit alternating current to the first bridge circuit in the form of an alternating magnetic field; the first bridge circuit is used to rectify the alternating current into low-voltage direct current.

In the case of forward operation, the controllable switch tube of the first bridge circuit is not turned on, and the controllable switch tube of the second bridge circuit is turned on according to a fixed duty cycle. Please refer to FIG. 2 , specifically, in the first bridge circuit, the first controllable switch S1 and the second controllable switch S2 are non-conductive. The third controllable switch S3 and the fourth controllable switch S4 are complementarily turned on with a duty cycle of 0.5, and the fifth controllable switch S5 and the sixth controllable switch S6 are complementarily turned on with a duty cycle of 0.5; The three controllable switch tubes S3 and the sixth controllable switch S6 are turned on synchronously, and the fourth controllable switch tube S4 and the fifth controllable switch tube S5 are turned on synchronously.

By using the above control method, the high-voltage direct current of the high-voltage battery can be converted into low-voltage direct current to supply the low-voltage battery, so as to achieve the effect of charging the low-voltage battery, so that the low-voltage battery can provide low-voltage direct current to other devices to ensure the normal operation of other devices.

In addition to the forward operation, the bidirectional resonant circuit can also operate in the reverse direction. The working flow of the reverse operation is described below: the first bridge circuit is used to invert low-voltage direct current into alternating current and transmit it to the transformer T; the transformer T is used to transmit alternating current to the resonant circuit in the form of an alternating magnetic field; the resonant circuit is used to resonate the alternating current, and transmit the resonated alternating current to the second bridge circuit; the second bridge circuit The circuit is used to rectify alternating current to high voltage direct current.

Two control methods when working in reverse are described below:

The first:

In the set period Ts, the controllable switch tube of the first bridge circuit is turned on with a fixed duty cycle of 0.5, and the controllable switch tube of the second bridge circuit is turned on with an adjustable duty cycle.

Please refer to FIG. 3 , specifically, in the first bridge circuit, the first controllable switch S1 and the second controllable switch S2 are complementarily turned on according to a fixed duty ratio of 0.5. That is, within a set period TS, the first controllable switch S1 is turned on first for the first set period T1 for Ts/2, and the rest of Ts/2 are turned off; the second controllable switch S2 is first turned off for Ts/2, and then The first set period T1 is turned on again.

In the second bridge circuit, within a set period Ts, when the first controllable switch S1 is in the conduction period T1, the third controllable switch S3 and the fifth controllable switch The tube S5 is synchronously turned on after delaying the set time period T3; when the second controllable switch tube S2 is in the conduction period T1, the third controllable switch tube S3 and the fifth controllable switch tube S3 and the fifth controllable switch The tube S5 is synchronously turned on after being delayed by the set time period T3; the fourth controllable switch tube S4 and the sixth controllable switch tube S6 are not turned on. Synchronous conduction means that the time point of starting conduction, the duration of conduction, and the time point of ending conduction are all the same.

Specifically, referring to FIG. 3 , in a set period: after the first controllable switch S1 is turned on for a duration of Ts/2, the rest of the Ts/2 duration is turned off; the second controllable switch S2 is turned off first for a duration of Ts/2 , the rest of the Ts/2 duration is turned on. During the conduction period T1 of the first controllable switch tube S1, after the first controllable switch tube S1 starts to be turned on, the third controllable switch tube S3 and the fifth controllable switch tube S5 start to be turned on after a delay of T3; After the third controllable switch tube S3 and the fifth controllable switch tube S5 are turned on for the second set period T2, the duration of T3 is turned off. During the conduction period T1 of the second controllable switch tube S2, after the second controllable switch tube S2 starts to be turned on, the third controllable switch tube S3 and the fifth controllable switch tube S5 start to be turned on after a delay of T3 time. After the third controllable switch tube S3 and the fifth controllable switch tube S5 are turned on for the second set period T2, the duration of T3 is turned off. During the whole process, the fourth controllable switch S4 and the sixth controllable switch S6 are not conducting.

2*T3+T2=Ts/2; T3=(0.5-D)*Ts/2, T2=D*Ts. D is the duty ratio of the third controllable switch tube S3 and the fifth controllable switch tube S5, and the range of the duty ratio is: 0<D≤0.5. T3 is the turn-on delay time of the third controllable switch S3 and the fifth controllable switch S5 , and T2 is the turn-on time of the third controllable switch S3 and the fifth controllable switch S5 .

That is, the third controllable switch tube S3 and the fifth controllable switch tube S5 start to be turned on after the first controllable switch tube S1 is turned on after a delay of T3, and the second controllable switch tube S2 is turned on. Start to delay T3 time and then start conducting.

With the first control method, for the case where the first bridge circuit is a half bridge circuit, no elements are added, and the third controllable switch S3 and the fifth controllable switch S5 are controlled to be turned on, thereby increasing the reverse operation time. voltage range, thus providing a wider voltage range for high-voltage batteries. In addition, if any one of the third controllable switch S3 or the fifth controllable switch S5 fails, the fourth controllable switch S4 and the sixth controllable switch S6 can be controlled, respectively, according to the third controllable switch. The conduction mode of the tube S3 and the fifth controllable switch tube S5 is conducted to ensure that the circuit can continue to be used normally. Especially when the circuit is applied to equipment such as automobiles, the use of the fourth controllable switch tube S4 and the sixth controllable switch tube S6 as backup controllable switch tubes can avoid the occurrence of danger.

The second:

Please refer to FIG. 4 , specifically, in the first bridge circuit, the first controllable switch S1 and the second controllable switch S2 are complementarily turned on according to a duty ratio of 0.5. That is, within a set period TS, the first controllable switch S1 is turned on first for the first set period T1 for Ts/2, and the rest of Ts/2 are turned off; the second controllable switch S2 is first turned off for Ts/2, and then The first set period T1 is turned on again.

In the second bridge circuit, in the conduction period T1 of the first controllable switch S1, the third controllable switch S3 and the fifth controllable switch S5 are delayed by a set time period T3 Start conduction; in the conduction period of the second controllable switch S2, the fourth controllable switch S4 and the sixth controllable switch S6 are synchronously turned on after a delay of the set time period T3 .

Specifically, referring to FIG. 4 , in a set period: after the first controllable switch S1 is turned on for Ts/2 first, the rest of the Ts/2 are turned off; the second controllable switch S2 is turned off first after Ts/2 , the rest of the Ts/2 duration is turned on. During the conduction period T1 of the first controllable switch tube S1, after the first controllable switch tube S1 starts to be turned on, the third controllable switch tube S3 and the fifth controllable switch tube S5 start to be turned on after a delay of T3; After the third controllable switch tube S3 and the fifth controllable switch tube S5 are turned on for the second set period T2, the duration of T3 is turned off. During the conduction period T1 of the second controllable switch tube S2, after the second controllable switch tube S2 starts to be turned on, the fourth controllable switch tube S4 and the sixth controllable switch tube S6 start to be turned on after a delay of T3 time. After the fourth controllable switch tube S4 and the sixth controllable switch tube S6 are turned on for the second set period T2, the duration of T3 is turned off.

2*T3+T2=Ts/2; T3=(0.5-D)*Ts/2, T2=D*Ts. D is the duty ratio of the third controllable switch tube S3 and the fifth controllable switch tube S5, and the range of the duty ratio is: 0<D≤0.5. T3 is the turn-on delay time of the third controllable switch S3 and the fifth controllable switch S5 , and T2 is the turn-on time of the third controllable switch S3 and the fifth controllable switch S5 . In addition, D is also the duty ratio of the fourth controllable switch tube S4 and the sixth controllable switch tube S6, and the range of the duty ratio is: 0<D≤0.5; T3 is also the fourth controllable switch tube S4 and the sixth controllable switch tube S6. The turn-on delay time of the sixth controllable switch tube S6, T2 is also the turn-on time length of the fourth controllable switch tube S4 and the sixth controllable switch tube S6.

That is, the third controllable switch S3 and the fifth controllable switch S5 need to be turned on after the first controllable switch S1 starts to turn on after a delay of T3 time. The fourth controllable switch S4 and the sixth controllable switch S6 need to be turned on after the second controllable switch S2 starts to be turned on after a delay of T3 time.

With this second control method, no additional components are added. By controlling the third controllable switch S3, the fourth controllable switch S4, the fifth controllable switch S5 and the sixth controllable switch S6 to conduct, the The voltage range when working in reverse, thus providing a wider voltage range for high-voltage batteries. Moreover, in the second control method, the third to sixth controllable switches S6 are all turned on, so the usage of the four controllable switches is relatively balanced, so the service life of the four controllable switches is relatively close, Avoid conduction of some controllable switches and non-conduction of some controllable switches, resulting in unequal lifespans and affecting the overall lifespan of the circuit.

Second Embodiment

Referring to FIG. 5 , in this embodiment, the bidirectional resonant circuit includes a low-voltage battery, a first bridge circuit, a transformer T, a resonant circuit, a second bridge circuit and a high-voltage battery. The first bridge circuit is the second full bridge circuit, and the second bridge circuit is the first full bridge circuit. The second bridge circuit in FIG. 5 is the same as the second bridge circuit in the first embodiment, and the difference lies in the first bridge circuit.

Specifically, the second full-bridge circuit includes a seventh controllable switch S7, an eighth controllable switch S8, a ninth controllable switch S9, and a tenth controllable switch S10. The transformer T includes a primary winding and a secondary winding. The resonant circuit includes a capacitor C and an inductor L. The first full-bridge circuit includes a third controllable switch S3, a fourth controllable switch S4, a fifth controllable switch S5 and a sixth controllable switch S6; the seventh controllable switch S7 and The eighth controllable switch S8 is located in the same half bridge. In the half bridge, the seventh controllable switch S7 is connected to the positive electrode of the low-voltage battery, and the eighth controllable switch S8 is connected to the negative electrode of the low-voltage battery. The ninth controllable switch S9 and the tenth controllable switch S10 are located in the same half bridge. In the half bridge, the ninth controllable switch S9 is connected to the positive electrode of the low-voltage battery, and the tenth controllable switch S10 Connect to the negative terminal of the low voltage battery. One end of the primary winding is connected to the third connection node, and the other end of the primary winding is connected to the fourth connection node; the third connection node is located between the seventh controllable switch S7 and the eighth controllable switch S8, and the fourth connection node It is located between the ninth controllable switch tube S9 and the tenth controllable switch tube S10.

The resonant circuit includes a capacitor C and an inductor L, one end of the capacitor C is connected to one end of the primary winding, and the other end of the primary winding is connected to one end of the inductor L. The other end of the capacitor C is connected to the first connection node, and the other end of the inductor L is connected to the second connection node. The first connection node is set between the third controllable switch tube S3 and the fourth controllable switch tube S4, and the second connection node is set between the fifth controllable switch tube S5 and the sixth controllable switch tube S6. The third controllable switch S3 and the fourth controllable switch S4 form a half bridge. In the half bridge, the third controllable switch S3 is connected to the positive pole of the high-voltage battery, and the fourth controllable switch S4 is connected to the positive pole of the high-voltage battery. Negative connection. The fifth controllable switch tube S5 and the sixth controllable switch tube S6 form a half bridge. In the half bridge, the fifth controllable switch tube S5 is connected to the positive pole of the high-voltage battery, and the sixth controllable switch tube S6 is connected to the positive pole of the high-voltage battery. negative connection.

In the case of forward operation, within the set period Ts, the controllable switch of the first bridge circuit is not turned on, and the controllable switch of the second bridge circuit is turned on according to a fixed duty cycle. Please refer to FIG. 6 , specifically, in the first bridge circuit, the seventh controllable switch S7 to the tenth controllable switch S10 are not conducting. The third controllable switch S3 and the fourth controllable switch S4 are complementarily turned on with a duty cycle of 0.5, and the fifth controllable switch S5 and the sixth controllable switch S6 are complementarily turned on with a duty cycle of 0.5; The three controllable switches S3 and the sixth controllable switch S6 are turned on synchronously, and the fourth controllable switch S4 and the fifth controllable switch S5 are turned on synchronously.

Two control methods when working in reverse are described below:

The first:

Please refer to FIG. 7 , specifically, in the first bridge circuit, the seventh controllable switch S7 and the eighth controllable switch are complementarily turned on according to a fixed duty cycle of 0.5; the ninth controllable switch S9 and the tenth The controllable switch tube S10 is complementarily turned on according to a fixed duty cycle of 0.5. The seventh controllable switch S7 and the tenth controllable switch S10 are synchronously turned on, and the eighth controllable switch S8 and the ninth controllable switch S9 are synchronously turned on.

Hereinafter, when describing the controllable switch transistor in the second bridge circuit, the seventh controllable switch transistor S7 and the eighth controllable switch transistor are used as reference for description.

In a set period, when the seventh controllable switch is in the conduction period, in the second bridge circuit, the third controllable switch and the fifth controllable switch are extended. After the set time period, the conduction starts; in the conduction period of the eighth controllable switch tube, the third controllable switch tube and the fifth controllable switch tube are synchronously turned on after a set time period. On; the fourth controllable switch tube and the sixth controllable switch tube are not conductive.

Specifically, referring to FIG. 7 , in a set period: after the seventh controllable switch S7 is turned on for Ts/2 first, the remaining Ts/2 are turned off; after the eighth controllable switch is first turned off for Ts/2, The remaining Ts/2 durations are turned on. During the conduction period of the seventh controllable switch S7, after the seventh controllable switch S7 starts to be turned on, the third controllable switch S3 and the fifth controllable switch S5 start to be turned on after a delay of T3; After the third controllable switch tube S3 and the fifth controllable switch tube S5 are turned on for the second set period T2, the duration of T3 is turned off. During the conduction period of the eighth controllable switch tube, after the eighth controllable switch tube starts to conduct, the third controllable switch tube S3 and the fifth controllable switch tube S5 start to be turned on after a delay of T3, and the third controllable switch tube S3 and the fifth controllable switch tube After the control switch S3 and the fifth controllable switch S5 are turned on for the second set period T2, the time period T3 is turned off. During the whole process, the fourth controllable switch S4 and the sixth controllable switch S6 are not conducting.

2*T3+T2=Ts/2; T3=(0.5-D)*Ts/2, T2=D*Ts. D is the duty ratio of the third controllable switch tube S3 and the fifth controllable switch tube S5, and the range of the duty ratio is: 0<D≤0.5. T3 is the turn-on delay time of the third controllable switch S3 and the fifth controllable switch S5, and T2 is the turn-on time of the third controllable switch S3 and the fifth controllable switch S5.

That is, within a set period, the third controllable switch S3 and the fifth controllable switch S5 are turned on twice, and the seventh controllable switch S7 is turned on once after the turn-on time of T3, and After the turn-on of the eighth controllable switch tube starts to be turned on once after a time length of T3.

Using the first control method, for the case where the first bridge circuit is a full bridge circuit, no elements are added, and the third controllable switch S3 and the fifth controllable switch S5 are controlled to be turned on, thereby increasing the reverse operation time. voltage range, thus providing a wider voltage range for high-voltage batteries. And in the case that the third controllable switch S3 or the fifth controllable switch S5 fails, the fourth controllable switch S4 and the sixth controllable switch S6 can be used. So as to avoid circuit failure during use, causing danger.

The second:

Please refer to FIG. 8 , specifically, in the first bridge circuit, the seventh controllable switch S7 and the eighth controllable switch are complementarily turned on according to the duty cycle of 0.5; the ninth controllable switch and the tenth controllable switch are complementary. The switch tube is turned on complementary according to the duty of 0.5. The seventh controllable switch S7 and the tenth controllable switch are synchronously turned on, and the eighth controllable switch S8 and the ninth controllable switch are synchronously turned on.

Hereinafter, when describing the controllable switch transistors in the second bridge circuit, the seventh controllable switch transistor S7 and the eighth controllable switch transistor S8 are used as reference for description.

In the second bridge circuit, in the conduction period of the seventh controllable switch tube, the third controllable switch tube and the fifth controllable switch tube start to be turned on after a set period of time; During the conduction period of the eighth controllable switch tube, the fourth controllable switch tube and the sixth controllable switch tube are synchronously turned on after a delay of a set period of time.

Specifically, referring to FIG. 8 , in a set period: after the seventh controllable switch S7 is turned on for Ts/2 first, the remaining Ts/2 are turned off; after the eighth controllable switch is first turned off for Ts/2, The remaining Ts/2 durations are turned on. During the conduction period of the seventh controllable switch S7, after the seventh controllable switch S7 starts to be turned on, the third controllable switch S3 and the fifth controllable switch S5 start to be turned on after a delay of T3; After the third controllable switch tube S3 and the fifth controllable switch tube S5 are turned on for the second set period T2, the duration of T3 is turned off. During the conduction period of the eighth controllable switch S8, after the eighth controllable switch S8 starts to be turned on, the fourth controllable switch S4 and the sixth controllable switch S6 start to be turned on after a delay of T3. After the fourth controllable switch tube S4 and the sixth controllable switch tube S6 are turned on for the second set period T2, the duration of T3 is turned off.

2*T3+T2=Ts/2; T3=(0.5-D)*Ts/2, T2=D*Ts. D is the duty ratio of the third controllable switch tube S3 and the fifth controllable switch tube S5, and the range of the duty ratio is: 0<D≤0.5. T3 is the turn-on delay time of the third controllable switch S3 and the fifth controllable switch S5, and T2 is the turn-on time of the third controllable switch S3 and the fifth controllable switch S5. D is also the duty ratio of the fourth controllable switch tube S4 and the sixth controllable switch tube S6, and the range of the duty ratio is: 0<D≤0.5; T3 is also the fourth controllable switch tube S4 and the sixth controllable switch tube S6. The turn-on delay time of the controllable switch tube S6, T2 is also the turn-on time length of the fourth controllable switch tube S4 and the sixth controllable switch tube S6.

That is, in a set period: the third controllable switch S3 and the fifth controllable switch S5 are turned on once, and it is necessary to delay the conduction of the seventh controllable switch S7 for a period of T3, and then start to turn on. Pass. The fourth controllable switch tube S4 and the sixth controllable switch tube S6 are turned on once, and the turn-on of the tenth controllable switch tube S10 needs to be delayed for T3 time before the turn-on of the tenth controllable switch tube S10 starts.

It can be seen from the above that the embodiment of the present application provides a bidirectional resonant circuit, which is connected to the first bridge circuit of the low-voltage battery, whether it is a half-bridge circuit or a full-bridge circuit, and can be connected to the high-voltage battery through control without adding other components. The controllable switch tube of the second bridge circuit is turned on to increase the voltage range during reverse operation. The number of components of the product is reduced, so the volume of the product is reduced, correspondingly, the cost is reduced, and the loss of the circuit itself is also reduced.

Moreover, all the controllable switches of the second bridge circuit may be turned on, or only part of them may be turned on. Therefore, the scope of use is also wider.

There are two reverse operation control methods in the first embodiment and the second embodiment. It can be known that the controllable switch tubes of the second bridge circuit may be part of the controllable switch tubes turned on, or all the controllable switches may be turned on. Tube conducts. When the control method in which some of the controllable switch tubes are turned on is adopted, the remaining controllable switch tubes can be used as spare parts to avoid danger. By adopting the way of conducting all the controllable switches, the lifespan of all the controllable switches can be balanced, so as to prolong the lifespan of the product.

It can be understood that, in the above embodiment, the resonant circuit includes an inductor L and a capacitor C, the first end of the capacitor C is connected to the first end of the primary winding of the transformer T, and the second end of the capacitor C is connected. The terminal is connected to a first connection node; the first connection node is located between the third controllable switch tube S3 and the fourth controllable switch tube S4. The first end of the inductor L is connected to the second end of the primary winding of the transformer T, and the second end of the inductor L is connected to the second connection node; the second connection node is located in the fifth controllable switch tube between S5 and the sixth controllable switch tube S6. The use of this kind of resonant circuit has fewer components, simpler structure and lower cost, which is beneficial to reduce the cost of the entire product and also reduces the loss of the circuit itself.

Further, the embodiments of the present application also provide an automobile, including an on-board power supply system, and the on-board power supply system includes the bidirectional resonant circuit described in any of the embodiments of the present application.

The embodiments of the present application have been introduced in detail above, and specific examples are used herein to illustrate the principles and implementations of the present application. The descriptions of the above embodiments are only used to help understand the methods and core ideas of the present application; at the same time, for Persons of ordinary skill in the art, based on the idea of the present application, may have changes in the specific implementation manner and application scope. In conclusion, the contents of this description should not be construed as a limitation on the present application.

Claims

A bidirectional resonant circuit is characterized in that it comprises a first bridge circuit, a transformer, a resonant circuit and a second bridge circuit; the first bridge circuit is connected to the secondary winding of the transformer, and the resonant circuit is One end is connected to the primary winding of the transformer, and the other end of the resonant circuit is connected to the second bridge circuit;

When the bidirectional resonant circuit is in a reverse working state, within a set period, the controllable switch tube of the first bridge circuit is turned on with a fixed duty cycle, and the controllable switch of the second bridge circuit is turned on. The tube is turned on with an adjustable duty cycle;

The first bridge circuit is used to invert low-voltage direct current into alternating current and transmit it to the transformer; the transformer is used to transmit the alternating current to the resonant circuit in the form of an alternating magnetic field; the resonant circuit is used to convert the alternating current. Resonance is performed, and the resonated alternating current is transmitted to the second bridge circuit; the second bridge circuit is used to rectify the alternating current into high-voltage direct current.
The bidirectional resonant circuit according to claim 1, wherein the fixed duty cycle is 0.5, and the adjustable duty cycle range is: 0<adjustable duty cycle≤0.5.
The bidirectional resonant circuit according to claim 1, wherein part or all of the controllable switch tubes of the second bridge circuit are turned on with an adjustable duty cycle.
The bidirectional resonant circuit according to claim 1, wherein the first bridge circuit comprises a half-bridge circuit, and the half-bridge circuit comprises a first controllable switch tube and a second controllable switch tube; A controllable switch tube and the second controllable switch tube complementarily conduct at the fixed duty cycle;

The second bridge circuit includes a first full-bridge circuit, and the first full-bridge circuit includes a third controllable switch, a fourth controllable switch, a fifth controllable switch and a sixth controllable switch; The third controllable switch transistor and the fourth controllable switch transistor are located in the same half bridge, and the fifth controllable switch transistor and the sixth controllable switch transistor are located in the same half bridge;

During the conduction period of the first controllable switch tube, the third controllable switch tube and the fifth controllable switch tube start to be turned on after a set period of time; in the second controllable switch tube During the conduction period of the tube, the third controllable switch tube and the fifth controllable switch tube are synchronously turned on after a delay of a set time period; the fourth controllable switch tube and the sixth controllable switch tube The switch tube is not conducting.
The bidirectional resonant circuit according to claim 1, wherein the first bridge circuit comprises a half-bridge circuit, and the half-bridge circuit comprises a first controllable switch tube and a second controllable switch tube; A controllable switch tube and the second controllable switch tube complementarily conduct at the fixed duty cycle;

The second bridge circuit includes a first full-bridge circuit, and the first full-bridge circuit includes a third controllable switch, a fourth controllable switch, a fifth controllable switch and a sixth controllable switch; The third controllable switch transistor and the fourth controllable switch transistor are located in the same half bridge, and the fifth controllable switch transistor and the sixth controllable switch transistor are located in the same half bridge;

During the conduction period of the first controllable switch tube, the third controllable switch tube and the fifth controllable switch tube start to be turned on after a set period of time; in the second controllable switch tube During the conduction period of the tube, the fourth controllable switch tube and the sixth controllable switch tube are synchronously turned on after a delay of a set period of time.
The bidirectional resonant circuit according to claim 1, wherein the first bridge circuit comprises a second full bridge circuit, and the second full bridge circuit comprises a seventh controllable switch and an eighth controllable switch , the ninth controllable switch tube and the tenth controllable switch tube; the seventh controllable switch tube and the eighth controllable switch tube are located in the same half bridge, the ninth controllable switch tube and the tenth controllable switch tube The controllable switch tubes are located in the same half-bridge; the seventh controllable switch tube and the eighth controllable switch tube are complementarily turned on with a fixed duty cycle, and the ninth controllable switch tube and the tenth controllable switch tube The switch tubes are complementarily turned on at a fixed duty ratio; the seventh controllable switch tube and the tenth controllable switch tube are turned on synchronously, and the eighth controllable switch tube and the ninth controllable switch tube are synchronous turn on;

The second bridge circuit includes a first full-bridge circuit, and the first full-bridge circuit includes a third controllable switch, a fourth controllable switch, a fifth controllable switch and a sixth controllable switch; The third controllable switch transistor and the fourth controllable switch transistor are located in the same half bridge, and the fifth controllable switch transistor and the sixth controllable switch transistor are located in the same half bridge;

During the conduction period of the seventh controllable switch tube, the third controllable switch tube and the fifth controllable switch tube start to be turned on after a set period of time; in the eighth controllable switch tube During the conduction period of the tube, the third controllable switch tube and the fifth controllable switch tube are synchronously turned on after a delay of a set time period; the fourth controllable switch tube and the sixth controllable switch tube The switch tube is not conducting.
The bidirectional resonant circuit according to claim 1, wherein the first bridge circuit comprises a second full bridge circuit, and the second full bridge circuit comprises a seventh controllable switch and an eighth controllable switch , the ninth controllable switch tube and the tenth controllable switch tube; the seventh controllable switch tube and the eighth controllable switch tube are located in the same half bridge, the ninth controllable switch tube and the tenth controllable switch tube The controllable switch tubes are located in the same half-bridge; the seventh controllable switch tube and the eighth controllable switch tube are complementarily turned on with a fixed duty cycle, and the ninth controllable switch tube and the tenth controllable switch tube The switch tubes are complementarily turned on at a fixed duty ratio; the seventh controllable switch tube and the tenth controllable switch tube are turned on synchronously, and the eighth controllable switch tube and the ninth controllable switch tube are synchronous turn on;

The second bridge circuit includes a first full-bridge circuit, and the first full-bridge circuit includes a third controllable switch, a fourth controllable switch, a fifth controllable switch and a sixth controllable switch; The third controllable switch transistor and the fourth controllable switch transistor are located in the same half bridge, and the fifth controllable switch transistor and the sixth controllable switch transistor are located in the same half bridge;

During the conduction period of the seventh controllable switch tube, the third controllable switch tube and the fifth controllable switch tube start to be turned on after a set period of time; in the eighth controllable switch tube During the conduction period of the tube, the fourth controllable switch tube and the sixth controllable switch tube are synchronously turned on after a delay of a set period of time.
The bidirectional resonant circuit according to any one of claims 4 to 7, wherein the resonant circuit comprises an inductor and a capacitor, and a first end of the capacitor is connected to a first end of the primary winding of the transformer, The second end of the capacitor is connected to a first connection node; the first connection node is located between the third controllable switch tube and the fourth controllable switch tube;

The first end of the inductor is connected to the second end of the primary winding of the transformer, and the second end of the inductor is connected to the second connection node; the second connection node is located at the fifth controllable switch tube and the sixth between the controllable switches.
The bidirectional resonant circuit according to claim 1, wherein when the bidirectional resonant circuit is in a forward working state, within a set period, the controllable switch of the second bridge circuit uses the The fixed duty cycle is turned on, and the controllable switch tube of the first bridge circuit is not turned on;

The second bridge circuit is used to invert high-voltage direct current into alternating current and transmit it to the resonant circuit; the resonant circuit is used to resonate the alternating current, and transmit the resonated alternating current to the transformer; the transformer is used for The alternating current is transmitted to the first bridge circuit in the form of an alternating magnetic field; the first bridge circuit is used to rectify the alternating current into low-voltage direct current.
An automobile, comprising an on-board power supply system, characterized in that, the on-board power supply system comprises the bidirectional resonant circuit of any one of claims 1-9.