CN114172375B - Direct current converter - Google Patents

Abstract

The invention discloses a direct current converter which comprises K inverter circuits, N transformers, M rectifying circuits, K input resonant circuits and M output resonant circuits. The input resonant circuit can provide resonant current for the inverter circuit, so that the current when at least one switching tube in the inverter circuit is turned off is smaller than the preset soft turn-off current, and the turn-off loss of the switching tube in the inverter circuit is reduced; the output resonant circuit can provide resonant current for the rectifying circuit connected with the output resonant circuit, so that the current when at least one switching tube in the rectifying circuit is switched off is smaller than the preset soft switching-off current, and the switching-off loss of the switching tube in the rectifying circuit is reduced. Therefore, the input resonant circuit and the output resonant circuit are respectively arranged, so that the current of the switching tube in the inverter circuit and the rectifying circuit when the switching tube is switched off is smaller than the preset soft switching-off current, and the switching-off loss of the switching tube is reduced.

Description

a DC converter

technical field

The invention relates to the technical field of power electronics, in particular to a direct current converter.

Background technique

Vehicle power systems and medium-voltage DC power distribution systems usually require power supplies of different voltage levels. Therefore, multi-port DC converters are required for voltage conversion.

However, the existing DC converter includes a power source, an inverter circuit, a transformer and a rectifier circuit, and the voltage of the power source is converted through the inverter circuit, the transformer and the rectifier circuit to supply power to a corresponding load. However, the inverter circuit and the rectifier circuit are usually provided with a switch tube, and the loss of the switch tube when turned on and off is relatively large, which makes the switching loss of the inverter circuit and the rectifier circuit relatively large, which hinders the circuit efficiency and power density. promote.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a DC converter, wherein by setting the input resonance circuit and the output resonance circuit respectively, the current when the switch tubes in the inverter circuit and the rectifier circuit are turned off can be smaller than the preset soft turn-off current, thereby Reduce the turn-off loss of the switch.

In order to solve the above technical problems, the present invention provides a DC converter, including K inverter circuits, N transformers and M rectifier circuits, where K and M are both positive integers, and N is a non-negative integer; each of the inverter circuits The input end of the transformer is connected to the power supply, and the output end is connected to the primary coil of one or more of the transformers, or to the input end of one or more of the rectifier circuits; the secondary coil of each transformer is connected to one or more of the rectifier circuits. The input ends of the plurality of rectifier circuits are connected, and the output ends of each of the rectifier circuits are connected to the load; it also includes:

K input resonant circuits, which are respectively connected with the K inverter circuits in one-to-one correspondence, are used to provide resonant current for the inverter circuits, so that the current of at least one switch tube in the inverter circuit is turned off The absolute value is less than the preset soft-off current;

The M output resonant circuits respectively connected to the M rectifier circuits in one-to-one correspondence are used to provide resonant current for the rectifier circuits connected to themselves, so that at least one switch tube in the rectifier circuit is turned off. The absolute value of the current is less than the preset soft-off current;

The absolute value of the difference between the resonant frequencies of any two resonant circuits is smaller than the preset frequency value.

Preferably, the input resonant circuit includes a first input resonant capacitor and a first input resonant inductance, which are used to provide a resonant current for the inverter circuit, so that at least one switch tube in the inverter circuit is turned off. The absolute value of the current is less than the preset soft-off current;

The first end of the first input resonant capacitor is connected to the first output end of the power supply and the first input end of the inverter circuit, and the second end is connected to the second output end of the power supply and the inverter circuit the second input terminal of the circuit is connected;

The first end of the first input resonant inductor is connected to the first output end of the inverter circuit, and the second end is connected to the first end of the primary coil of the transformer;

The second end of the primary coil of the transformer is connected to the second output end of the inverter circuit.

Preferably, the input resonant circuit includes a second input resonant capacitor and a second input resonant inductance, which are used to provide a resonant current for the inverter circuit, so that at least one switch tube in the inverter circuit is turned off. The absolute value of the current is less than the preset soft-off current;

The first end of the second input resonant inductor is connected to the first output end of the inverter circuit, and the second end is connected to the first end of the primary coil of the transformer;

The first end of the second input resonance capacitor is connected to the second output end of the inverter circuit, and the second end is connected to the second end of the primary coil of the transformer.

Preferably, the input resonant circuit or the output resonant circuit is a multi-element resonant circuit or a composite resonant circuit.

Preferably, the output resonant circuit includes a first output resonant capacitor and a first output resonant inductor, which are used to provide a resonant current for the rectifier circuit, so that the current of at least one switch in the rectifier circuit is absolutely The value is less than the preset soft-off current;

The first end of the first output resonant inductor is connected to the first end of the secondary coil of the transformer, and the second end is connected to the first input end of the rectifier circuit;

The first end of the first output resonance capacitor is connected to the first output end of the rectifier circuit and the first input end of the load, and the second end is connected to the second output end of the rectifier circuit and the load's first input end. the second input terminal is connected;

The second end of the secondary coil of the transformer is connected to the second input end of the rectifier circuit.

Preferably, the output resonant circuit includes a second output resonant capacitor and a second output resonant inductor, which are used to provide a resonant current for the rectifier circuit, so that the current of at least one switch tube in the rectifier circuit is absolutely The value is less than the preset soft-off current;

The first end of the second output resonant inductor is connected to the first end of the secondary coil of the transformer, and the second end is connected to the first output end of the rectifier circuit;

The first end of the second output resonance capacitor is connected to the second input end of the rectifier circuit, and the second end is connected to the second end of the secondary coil of the transformer.

Preferably, the inverter circuit is a combination of one or more of a full-bridge inverter circuit, a half-bridge inverter circuit and a single-tube inverter circuit.

Preferably, the rectifier circuit is a combination of one or more of a full-bridge rectifier circuit, a center-tapped rectifier circuit, a voltage-doubling rectifier circuit and a half-wave rectifier circuit.

Preferably, it also includes:

One or more controllers connected to the control terminals of each switch tube in the inverter circuit and each switch tube in the rectifier circuit, for controlling each switch tube in the inverter circuit and the rectifier The turn-on and turn-off of each switch in the circuit, and control the dead time interval between the turn-on times of the two switches in the same bridge arm;

The first end is connected to the first end of the primary coil of the transformer, and the second end is connected to the second end of the primary coil of the transformer. The inductor is used to make the inverter circuit or the rectifier circuit At least one switch tube is turned on at zero voltage.

The present application provides a DC converter, including K inverter circuits, N transformers, M rectifier circuits, K input resonant circuits, and M output resonant circuits. The input resonant circuit can provide a resonant current for the inverter circuit, so that the current when at least one switch tube in the inverter circuit is turned off is less than the preset soft turn-off current, thereby reducing the turn-off loss of the switch tube in the inverter circuit; the output The resonant circuit can provide resonant current for the rectifier circuit connected to itself, so that the current when at least one switch tube in the rectifier circuit is turned off is less than the preset soft turn-off current, thereby reducing the turn-off loss of the switch tube in the rectifier circuit. It can be seen that by setting the input resonant circuit and the output resonant circuit respectively in this application, the current when the switch tubes in the inverter circuit and the rectifier circuit are turned off can be smaller than the preset soft turn-off current, thereby reducing the turn-off loss of the switch tubes. .

Description of drawings

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

1 is a schematic structural diagram of a DC converter provided by the present invention;

Fig. 2 is the concrete structural schematic diagram of the first DC converter provided by the present invention;

FIG. 3 is a specific structural schematic diagram of the second type of DC converter provided by the present invention;

FIG. 4 is a specific structural schematic diagram of a third DC converter provided by the present invention;

Fig. 5 is the concrete structural schematic diagram of the fourth kind of DC converter provided by the present invention;

6 is a schematic structural diagram of a first full-bridge inverter circuit provided by the present invention;

7 is a schematic structural diagram of a second full-bridge inverter circuit provided by the present invention;

8 is a schematic structural diagram of a third full-bridge inverter circuit provided by the present invention;

9 is a schematic structural diagram of a half-bridge inverter circuit provided by the present invention;

10 is a schematic structural diagram of a single-tube inverter circuit provided by the present invention;

11 is an example diagram of a control sequence of a first inverter switch tube and a second inverter switch tube provided by the present invention;

12 is a schematic structural diagram of the first full-bridge rectifier circuit provided by the present invention;

13 is a schematic structural diagram of a second full-bridge rectifier circuit provided by the present invention;

14 is a schematic structural diagram of a center-tap rectifier circuit provided by the present invention;

15 is a schematic structural diagram of a half-wave rectifier circuit provided by the present invention;

FIG. 16 is another example diagram of the control sequence of the first inverter switch tube and the second inverter switch tube provided by the present invention.

Detailed ways

The core of the present invention is to provide a DC converter, wherein by setting the input resonance circuit and the output resonance circuit respectively, the current when the switch tubes in the inverter circuit and the rectifier circuit are turned off can be smaller than the preset soft turn-off current, thereby Reduce the turn-off loss of the switch.

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Please refer to FIG. 1, which is a schematic structural diagram of a DC converter provided by the present invention, including K inverter circuits, N transformers and M rectifier circuits, where K and M are both positive integers, and N is a non-negative integer ; The input end of each inverter circuit is connected to the power supply, and the output end is connected to the primary coil of one or more transformers, or to the input end of one or more of the rectifier circuits; the secondary coil of each transformer is connected to a The input ends of or multiple rectifier circuits are connected, and the output ends of each rectifier circuit are connected to the load; it also includes:

The K input resonant circuits 1 respectively connected to the K inverter circuits in a one-to-one correspondence are used to provide the resonant current for the inverter circuit, so that the absolute value of the current of at least one switch tube in the inverter circuit when it is turned off is smaller than the preset value. Set the soft-off current;

The M output resonant circuits 2 respectively connected to the M rectifier circuits in one-to-one correspondence are used to provide resonant current for the rectifier circuits connected to themselves, so that the absolute value of the current of at least one switch tube in the rectifier circuit when it is turned off is smaller than the preset value. Set the soft-off current;

The absolute value of the difference between the resonant frequencies of any two resonant circuits is smaller than the preset frequency value.

The applicant considers that both the inverter circuit and the rectifier circuit in the DC converter in the prior art are provided with switch tubes, and when the inverter circuit and the rectifier circuit work, their own switch tubes will be turned on or off accordingly, Accordingly, turn-on or turn-off losses are generated, thereby reducing the efficiency of the inverter circuit and the rectifier circuit.

In order to solve the above-mentioned technical problems, in this application, K input resonant circuits 1 which are respectively connected with K inverter circuits in one-to-one correspondence, and M output resonant circuits 2 which are respectively connected with M rectifier circuits in one-to-one correspondence, are provided. The input resonant circuit 1 provides a resonant current for the inverter circuit connected to itself, so that the absolute value of the current of at least one switch tube in the inverter circuit when it is turned off is less than the preset soft turn-off current, even if the switch tube is turned off, the current is The current through the switch itself is close to 0 (the optimal situation is that the current when the switch is turned off is 0), for example, within a preset range centered at 0, so that the switch can be turned off softly, reducing The turn-off loss of the switch tube; correspondingly, the output resonant circuit 2 can provide a resonant current for the rectifier circuit connected to itself, so that the switch tube in the rectifier circuit connected to itself can also achieve soft turn-off when it is turned off, reducing the The turn-off loss of the switch tube in the rectifier circuit improves the efficiency of the inverter circuit and the rectifier circuit.

It should be noted that the DC converter in this application is provided with N transformers and M rectifier circuits, wherein, multiple rectifier circuits may be connected to the same transformer, or each rectifier circuit may be connected to a transformer, or the A part of the rectification circuit is connected to one transformer, and the other part is connected to another transformer, which is not limited in this application. In addition, each rectifier circuit is respectively connected with its corresponding load, so as to realize the multi-port output of the DC converter.

It should also be noted that the output end of each inverter circuit can be connected to one or more transformers, so as to transmit energy to the rectifier circuit through the transformer; in particular, if the alternating current output by the inverter circuit is transmitted to the rectifier circuit When the required transformation ratio is 1, there is no need to set a transformer between the inverter circuit and the rectifier circuit, so as to reduce the cost.

In addition, the absolute value of the difference between the resonant frequencies between the input resonant circuit 1 and the output resonant circuit 2, or between the input resonant circuit 1 and the input resonant circuit 1, or between the output resonant circuit 2 and the output resonant circuit 2 is smaller than the predetermined value. Set the frequency value to ensure the normal operation of each inverter circuit and each rectifier circuit.

It should be noted that the preset frequency value between the resonant frequencies of two resonant circuits of the same type can be set to be smaller. For example, when the two resonant circuits are both series resonant circuits, or both are parallel resonant circuits, the preset frequency The frequency value is set to 0.1Hz, and if the types of the two resonant circuits are different, for example, one is series resonance and the other is parallel resonance, the preset frequency value can be set higher, such as 0.6Hz. This application only exemplifies the types of resonant circuits. Resonant circuits are not limited to series resonant circuits or parallel resonant circuits. Different types of resonant circuits such as ICF resonant circuits, OCS resonant circuits, multi-element resonant circuits or composite resonant circuits are all Can achieve. The multi-element resonant circuit can be, but is not limited to, a resonant circuit composed of multiple resonant inductors or resonant capacitors; the composite resonant circuit can also, but is not limited to, be a resonant circuit composed of a series resonant circuit and a parallel resonant circuit. The multi-element resonant circuit and the composite resonant circuit can reduce the power loss and improve the efficiency of the inverter circuit and the rectifier circuit while ensuring the soft turn-off of the switch tube. In addition, it should be noted that there may also be a rectifier circuit that is not connected to the output resonant circuit 2 in this application, that is, the switching loss in the rectifier circuit is not considered, and only the output of the rectifier circuit can be ensured; The inverter circuit of the input resonant circuit 1 is not connected, that is, the switching loss in the inverter circuit is not considered, and only the inverter circuit can be input, which is not limited in this application.

To sum up, in this application, by setting the input resonant circuit 1 and the output resonant circuit 2 respectively, the current when the switch tubes in the inverter circuit and the rectifier circuit are turned off can be smaller than the preset soft turn-off current, thereby reducing the switch tube’s current. turn-off losses.

On the basis of the above-mentioned embodiment:

Please refer to FIG. 2 , which is a schematic structural diagram of the first DC converter provided by the present invention.

As a preferred embodiment, the input resonant circuit 1 includes a first input resonant capacitor Cr1 and a first input resonant inductor Lr1, which are used to provide a resonant current for the inverter circuit, so that at least one switch in the inverter circuit is turned off When the absolute value of the current is less than the preset soft-off current;

The first end of the first input resonance capacitor Cr1 is connected to the first output end of the power supply and the first input end of the inverter circuit, and the second end is connected to the second output end of the power supply and the second input end of the inverter circuit;

The first end of the first input resonant inductor Lr1 is connected to the first output end of the inverter circuit, and the second end is connected to the first end of the primary coil of the transformer;

The second end of the primary coil of the transformer is connected to the second output end of the inverter circuit.

The input resonant circuit 1 in this embodiment includes a first input resonant capacitor Cr1 and a first input resonant inductor Lr1, and the first resonant capacitor and the first resonant inductor provide a resonant current for the inverter circuit, so that at least one of the inverter circuits The absolute value of the current of the switch tube when it is turned off is smaller than the preset soft turn-off current, so that the switch tube is softly turned off, and the first resonant capacitor and the first resonant inductance form a parallel resonant circuit, and the production cost is low.

It should be noted that the first input resonant inductance Lr1 in this application may be an inductance of a peripheral device, or may be a leakage inductance of a transformer or a parasitic inductance in a line, which is not limited in this application.

In addition, in FIG. 2 , one transformer is used to connect multiple rectifier circuits as an example. Of course, this application is not limited thereto.

As a preferred embodiment, the input resonant circuit 1 includes a second input resonant capacitor Cr2 and a second input resonant inductor Lr2, which are used to provide a resonant current for the inverter circuit, so that at least one switch tube in the inverter circuit is turned off When the absolute value of the current is less than the preset soft-off current;

The first end of the second input resonant inductor Lr2 is connected to the first output end of the inverter circuit, and the second end is connected to the first end of the primary coil of the transformer;

The first end of the second input resonance capacitor Cr2 is connected to the second output end of the inverter circuit, and the second end is connected to the second end of the primary coil of the transformer.

Please refer to FIG. 3 , which is a schematic structural diagram of a second type of DC converter provided by the present invention.

In this embodiment, the second input resonant inductor Lr2 and the second input resonant capacitor Cr2 form a series resonant circuit, so as to provide a resonant current for the inverter circuit, so that the absolute value of the current when at least one switch tube in the inverter circuit is turned off If the current is smaller than the preset soft turn-off current, the switch tube can be turned off softly, and the capacity of the power supply can also be reduced and the cost can be reduced.

It should be noted that the second input resonant inductance Lr2 in this application may be an inductance of a peripheral device, or may be a leakage inductance of a transformer or a parasitic inductance in a line, which is not limited in this application.

Of course, this application does not limit the structure of the input resonant circuit 1 mentioned in this embodiment, and more resonant inductances or resonant capacitors can be added to the input resonant circuit 1 mentioned in this embodiment to increase additional Effect.

As a preferred embodiment, the output resonant circuit 2 includes a first output resonant capacitor Co1 and a first output resonant inductance Lo1, which are used to provide a resonant current for the rectifier circuit, so that at least one switch in the rectifier circuit is turned off. The absolute value of the current is less than the preset soft-off current;

The first end of the first output resonant inductor Lo1 is connected to the first end of the secondary coil of the transformer, and the second end is connected to the first input end of the rectifier circuit;

The first end of the first output resonance capacitor Co1 is connected to the first output end of the rectifier circuit and the first input end of the load, and the second end is connected to the second output end of the rectifier circuit and the second input end of the load;

The second end of the secondary coil of the transformer is connected to the second input end of the rectifier circuit.

Please refer to FIG. 4 , which is a schematic structural diagram of a third type of DC converter provided by the present invention.

The output resonant circuit 2 in this embodiment is composed of a first output resonant capacitor Co1 and a first output resonant inductor Lo1, and forms parallel resonance, so as to provide a resonant current for the rectifier circuit, so that at least one switch in the rectifier circuit is turned off When the absolute value of the current is smaller than the preset soft turn-off current, to ensure the soft turn-off of the switch tube in the rectifier circuit.

It should be noted that the first output resonant inductance Lo1 in this application may be an inductance of a peripheral device, or may be a leakage inductance of a transformer or a parasitic inductance in a line, which is not limited in this application.

It should be noted that the absolute value of the difference between the resonant frequencies between any two resonant circuits 1 is less than the preset frequency value, that is, the following requirement: the input resonant circuit 1 and the output resonant circuit 2 respectively include only one resonant inductor. and a resonant capacitor, when Lr1*Cr1-Lo1*Co1<preset frequency value is satisfied, the inverter circuit and rectifier circuit can work normally.

As a preferred embodiment, the output resonant circuit 2 includes a second output resonant capacitor Co2 and a second output resonant inductor Lo2, which are used to provide a resonant current for the rectifier circuit, so that at least one switch tube in the rectifier circuit is turned off. The absolute value of the current is less than the preset soft-off current;

The first end of the second output resonant inductor Lo2 is connected to the first end of the secondary coil of the transformer, and the second end is connected to the first input end of the rectifier circuit;

The first end of the second output resonance capacitor Co2 is connected to the second input end of the rectifier circuit, and the second end is connected to the second end of the secondary coil of the transformer.

Please refer to FIG. 5 , which is a schematic structural diagram of a fourth type of DC converter provided by the present invention.

The output resonant circuit 2 in this embodiment is composed of a second output resonant capacitor Co2 and a second output resonant inductor Lo2, and forms series resonance, so that the absolute value of the current of at least one switch tube in the rectifier circuit when it is turned off is less than a preset value The soft turn-off current ensures the soft turn-off of the switch tube in the rectifier circuit, and can reduce the capacity of the power supply and reduce the cost.

It should be noted that, in FIGS. 4 and 5 , the input resonant circuit 1 includes the first input resonant inductor Lr1 and the first input resonant capacitor Cr1 as an example, of course, this is not limited in this application.

It should be noted that the second output resonant inductance Lo2 in this application may be an inductance of a peripheral device, or may be a leakage inductance of a transformer or a parasitic inductance in a line, which is not limited in this application.

Of course, this application does not limit the structure of the output resonant circuit 2 mentioned in this embodiment, and more resonant inductors or resonant capacitors can be added to the output resonant circuit 2 mentioned in this embodiment to increase additional Effect.

As a preferred embodiment, the inverter circuit is a combination of one or more of a full-bridge inverter circuit, a half-bridge inverter circuit, and a single-tube inverter circuit.

Please refer to FIG. 6, FIG. 7, FIG. 8, FIG. 9 and FIG. 10. FIG. 6 is a schematic structural diagram of a first full-bridge inverter circuit provided by the present invention, and FIG. 7 is a second full-bridge inverter circuit provided by the present invention. A schematic diagram of the structure of the circuit, FIG. 8 is a schematic structural diagram of a third full-bridge inverter circuit provided by the present invention, FIG. 9 is a schematic structural diagram of a half-bridge inverter circuit provided by the present invention, and FIG. 10 is a schematic diagram of a structure provided by the present invention. A schematic diagram of the structure of a single-tube inverter circuit.

The inverter circuit in this embodiment can be, but is not limited to, a full-bridge inverter circuit, a half-bridge inverter circuit, or a single-tube inverter circuit, and can also be a combination of various circuits, which can invert the DC power output by the power supply, that is, Can.

Wherein, the full-bridge inverter circuit shown in FIG. 7 is based on the full-bridge inverter circuit shown in FIG. Both ends of Q3 and the fourth inverter switch Q4 are connected in parallel with diodes respectively, and the diodes can also use the body diodes of each inverter switch. Semiconductor Field-Effect Transistor, Metal-Oxide Semiconductor Field Effect Transistor), IGBT (Insulated Gate Bipolar Transistor, Insulated Gate Bipolar Transistor), GTO (gate turn-off thyristor, can turn off thyristor), IGCT (Integrated Gate- CommutatedThyristor, integrated gate commutated thyristor) or HEMT (High Electron Mobility Transistor, high electron mobility transistor), which is not limited in this application.

In addition, when controlling the inverter switch tubes in the full-bridge inverter circuit, as shown in FIG. 11 , FIG. 11 is the control sequence of the first inverter switch tube and the second inverter switch tube provided by the present invention. sample graph. It can be seen that in one control period Ts, when the first inverter switch tube Q1 is controlled to be turned on, that is, when the input Vgs_Q1 to the control terminal of the first inverter switch tube Q1 is at a high level, Vgs_Q2 is at a low level, and the second inverter switch tube Q1 is at a low level. The switch Q2 is turned off; and when the second inverter switch Q2 is controlled to be turned on, that is, when the input Vgs_Q2 is a high level to the control terminal of the second inverter switch Q2, Vgs_Q1 is a low level, and the first inverter switch Q1 is turned off, so as to avoid the short circuit caused by turning on the first inverter switch Q1 and the second inverter switch Q2 at the same time.

In the half-bridge inverter circuit shown in FIG. 9 , a first inverter capacitor C1 and a second inverter capacitor C2 are also set to provide bias for the inverter circuit.

In addition, the single-tube inverter circuit can not only realize the inversion of the direct current output by the power supply, but also reduce the setting cost of the switch tube.

As a preferred embodiment, the rectifier circuit is a combination of one or more of a full-bridge rectifier circuit, a center-tap rectifier circuit, a voltage-doubling rectifier circuit, and a half-wave rectifier circuit.

The rectifier circuit in this embodiment can be, but is not limited to, a full-bridge rectifier circuit, a center-tapped rectifier circuit, a voltage-doubling rectifier circuit, or a half-wave rectifier circuit, which can rectify the alternating current output by the transformer, thereby supplying power to the load connected to itself, namely Can.

The voltage doubling rectifier circuit can amplify the input voltage by an integral multiple to supply power to the load.

Please refer to FIG. 12 , FIG. 13 , FIG. 14 and FIG. 15 , FIG. 12 is a schematic structural diagram of a first full-bridge rectifier circuit provided by the present invention, and FIG. 13 is a structural schematic diagram of a second full-bridge rectifier circuit provided by the present invention, FIG. 14 is a schematic structural diagram of a center-tap rectifier circuit provided by the present invention, and FIG. 15 is a structural schematic diagram of a half-wave rectifier circuit provided by the present invention.

The left side of the center-tapped rectifier circuit in FIG. 14 is the secondary coil of the transformer, and the left side of the half-wave rectifier circuit in FIG. 15 is also the secondary side coil of the transformer.

As a preferred embodiment, the power supply is a current source type power supply.

The power supply in the present application is a current source type power supply, and the current source type power supply can output a stable current to supply power to the load. In addition, a current source type power supply can be output by combining a voltage type power supply, an input capacitor, an input inductor, an output capacitor and an output inductor. As a preferred embodiment, the power supply includes a voltage-type power supply, an input capacitor and an input inductor; the load includes an output capacitor, an output inductor and an electrical load;

The first end of the input capacitor is connected to the output positive end of the voltage source power supply, and the second end is connected to the output negative end of the voltage source power source and the second input end of the inverter circuit;

The first end of the input inductor is connected to the first end of the input capacitor, and the second end is connected to the first input end of the inverter circuit;

The first end of the output inductor is connected to the first output end of the rectifier circuit, and the second end is connected to the input positive end of the electrical load;

The first end of the output capacitor is connected to the input positive end of the electric load, and the second end is connected to the input negative end of the electric load and the second output end of the rectifier circuit;

The input capacitance, input inductance, output capacitance and output inductance are used to form a current source type power supply with a voltage source type power supply.

It can be seen that when the user only has a voltage source type power supply, he can also use it to obtain a current source for output, so as to reduce the cost.

Of course, the power supply in this application is a power supply set by the user according to their own needs, which is not limited in this application.

As a preferred embodiment, it also includes:

One or more controllers connected to the control terminals of each switch tube in the inverter circuit and each switch tube in the rectifier circuit are used to control the turn-on of each switch tube in the inverter circuit and each switch tube in the rectifier circuit and turn off, and control the dead time interval between the turn-on times of the two switches in the same bridge arm;

The first end is connected to the first end of the primary coil of the transformer, and the second end is connected to the second end of the primary coil of the transformer. The inductor is used to make at least one switch tube in the inverter circuit or the rectifier circuit Zero voltage turn-on.

In this embodiment, an inductance is connected in parallel to the primary coil of the transformer, so that the controller realizes zero-voltage turn-on when controlling the switches in the inverter circuit and the rectifier circuit, and the two switches in the same bridge arm are turned on A dead time is added between the times to avoid a short circuit caused by the simultaneous opening of the two switches in the same bridge arm.

Please refer to FIG. 16 . FIG. 16 is another example diagram of the control sequence of the first inverter switch tube and the second inverter switch tube provided by the present invention. It can be seen that within a control period Ts, when the first inverter switch tube Q1 is controlled to be turned on, that is, when the input Vgs_Q1 to the control terminal of the first inverter switch tube Q1 is at a high level, Vgs_Q2 is at a low level, and the second inverter switch tube Q1 is at a low level. The switch Q2 is turned off. After the first inverter switch Q1 is controlled to be turned off, that is, after Vgs_Q1 is at a low level, there is a period of dead time td. After the dead time, the second inverter switch Q2 is controlled to be turned on. , that is, when the input Vgs_Q2 to the control terminal of the second inverter switch tube Q2 is at a high level, Vgs_Q1 is at a low level, and the first inverter switch tube Q1 is turned off. By setting the dead time, to ensure the charging and discharging of the parasitic capacitance of the second inverter switch transistor Q2, the zero-voltage turn-on of the second inverter switch transistor Q2 is realized.

It should also be noted that the inverter circuit and the rectifier circuit in the present application may be isolated from each other or short-circuited together at least at one end, which is not limited in the present application.

In addition, when controlling the inverter circuit and the rectifier circuit in this application, the control method of constant frequency and constant duty ratio can be used, and the control method of frequency conversion or variable duty ratio, phase shift control or two of them can also be used. or a mixed mode control of multiple compositions, which is not limited in this application.

The transformer in this application may also be a wire wound transformer, a planar transformer or an aliased transformer, which is not limited in this application.

The coupled magnetic circuit in the transformer may be constrained by a ferrite magnetic core, or a magnetic core made of other materials such as amorphous or nanocrystalline, or not constrained by a magnetic core, which is not limited in this application.

The resonance capacitor in this application may also be a parasitic capacitance in a circuit, such as a parasitic capacitance of a transformer, or an external independent capacitor, which is also not limited in this application.

It should be noted that VIN1 in the drawings of this application document is the input positive terminal of the circuit, VIN2 is the input negative terminal of the circuit, VOUT1 is the output positive terminal of the circuit, and VOUT2 is the output negative terminal of the circuit. Q1, Q2, Q3 and Q4 are switch tubes in the inverter circuit, and SR1, SR2, SR3 and SR4 are switch tubes in the rectifier circuit.

It should also be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply these entities or operations. There is no such actual relationship or sequence between operations. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device comprising a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (9)

1. A direct current converter is characterized by comprising K inverter circuits, N transformers and M rectifying circuits, wherein K and M are positive integers, and N is a non-negative integer; the input end of each inverter circuit is connected with a power supply, and the output end of each inverter circuit is connected with one or more primary coils of the transformer or the input ends of one or more rectifier circuits; the secondary coil of each transformer is connected with the input ends of one or more rectifying circuits, and the output end of each rectifying circuit is connected with a load; further comprising:

the K input resonant circuits are respectively connected with the K inverter circuits in a one-to-one correspondence mode and used for providing resonant current for the inverter circuits so that the absolute value of the current of at least one switching tube in the inverter circuits when the switching tube is switched off is smaller than the preset soft switching-off current;

the M output resonant circuits are respectively connected with the M rectifying circuits in a one-to-one correspondence manner and are used for providing resonant current for the rectifying circuits connected with the M output resonant circuits, so that the absolute value of the current of at least one switching tube in the rectifying circuits when the switching tube is switched off is smaller than the preset soft switching-off current;

the absolute value of the difference between the resonant frequencies of any two resonant circuits is less than a preset frequency value.

2. The direct current converter according to claim 1, wherein the input resonant circuit comprises a first input resonant capacitor and a first input resonant inductor, and is configured to provide a resonant current for the inverter circuit, so that an absolute value of a current of at least one switching tube in the inverter circuit when the switching tube is turned off is smaller than the preset soft off current;

the first end of the first input resonant capacitor is connected with the first output end of the power supply and the first input end of the inverter circuit, and the second end of the first input resonant capacitor is connected with the second output end of the power supply and the second input end of the inverter circuit;

the first end of the first input resonant inductor is connected with the first output end of the inverter circuit, and the second end of the first input resonant inductor is connected with the first end of the primary coil of the transformer;

and the second end of the primary coil of the transformer is connected with the second output end of the inverter circuit.

3. The direct current converter according to claim 1, wherein the input resonant circuit comprises a second input resonant capacitor and a second input resonant inductor, and is configured to provide a resonant current for the inverter circuit, so that an absolute value of a current of at least one switching tube in the inverter circuit when the switching tube is turned off is smaller than the preset soft off current;

the first end of the second input resonant inductor is connected with the first output end of the inverter circuit, and the second end of the second input resonant inductor is connected with the first end of the primary coil of the transformer;

and the first end of the second input resonant capacitor is connected with the second output end of the inverter circuit, and the second end of the second input resonant capacitor is connected with the second end of the primary coil of the transformer.

4. The dc converter of claim 1, wherein the input resonant circuit or the output resonant circuit is a multi-element resonant circuit or a composite resonant circuit.

5. The direct current converter according to claim 1, wherein the output resonant circuit comprises a first output resonant capacitor and a first output resonant inductor, and is used for providing resonant current for the rectifying circuit, so that the absolute value of the current of at least one switching tube in the rectifying circuit when the switching tube is switched off is smaller than the preset soft switching-off current;

the first end of the first output resonant inductor is connected with the first end of the secondary coil of the transformer, and the second end of the first output resonant inductor is connected with the first input end of the rectifying circuit;

the first end of the first output resonant capacitor is connected with the first output end of the rectifying circuit and the first input end of the load, and the second end of the first output resonant capacitor is connected with the second output end of the rectifying circuit and the second input end of the load;

and the second end of the secondary coil of the transformer is connected with the second input end of the rectifying circuit.

6. The direct current converter according to claim 1, wherein the output resonant circuit comprises a second output resonant capacitor and a second output resonant inductor, and is used for providing resonant current for the rectifying circuit, so that the absolute value of the current of at least one switching tube in the rectifying circuit when the switching tube is switched off is smaller than the preset soft switching-off current;

the first end of the second output resonant inductor is connected with the first end of the secondary coil of the transformer, and the second end of the second output resonant inductor is connected with the first input end of the rectifying circuit;

and the first end of the second output resonant capacitor is connected with the second input end of the rectifying circuit, and the second end of the second output resonant capacitor is connected with the second end of the secondary coil of the transformer.

7. The dc converter of claim 1, wherein the inverter circuit is a combination of one or more of a full-bridge inverter circuit, a half-bridge inverter circuit, and a single-tube inverter circuit.

8. The dc converter according to claim 1, wherein the rectifier circuit is a combination of one or more of a full-bridge rectifier circuit, a center-tap rectifier circuit, a voltage doubler rectifier circuit, and a half-wave rectifier circuit.

9. The dc converter of any of claims 1-8, further comprising:

the one or more controllers are connected with the control ends of the switching tubes in the inverter circuit and the rectifying circuit and are used for controlling the on and off of the switching tubes in the inverter circuit and the rectifying circuit and controlling the dead time of the interval between the on times of the two switching tubes in the same bridge arm;

and the inductor is used for enabling at least one switching tube in the inverter circuit or the rectifying circuit to be switched on at zero voltage.

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