KR101761571B1 - Current injection resonant converter - Google Patents

Abstract

The present invention relates to a resonance type converter for wireless power transmission in which a current is injected into or discharged from a capacitor of a resonance tank so as to correspond to a change in resonance tank or a change in output voltage according to a change in input / To a current injection type resonance type converter.
A current injection type resonance type converter according to the present invention includes: a resonance type converter including a resonance tank; A current injection circuit for injecting the current to the resonance capacitor (Cr) of the resonance tank; A transformer for transmitting the voltage supplied from the resonant converter to the secondary-side receiving coil from the primary-side transmitting coil; And a control unit for controlling operations of the resonant converter and the current injection circuit.

Description

Current injection resonant converter < RTI ID = 0.0 >

The present invention relates to a resonance type converter, and in particular, in a resonance type converter for wireless power transmission, a current is injected into or discharged from a capacitor of a resonance tank in order to cope with a change in output voltage or a change in input / To a current injection type resonance type converter which controls the output voltage to be constant.

Generally, a half bridge LLC resonant converter is favored for high efficiency acquisition over a wide load range for wireless power transmission. In this conventional half bridge LLC resonant converter, resonance is generated between the resonant inductor Lr and the resonant capacitor Cr to perform wireless power transmission through the transmission / reception coils Tx and Rx corresponding to the first and second coils of the transformer do.

At this time, as the transmission distance between the transmission and reception coils Tx and Rx becomes longer, the magnetic coupling between the transmission and reception coils Tx and Rx decreases, and the ratio of the resonance inductance Lr to the magnetization inductance Lm of the transformer ) Is increased. As the inductance changes, resonance tanks are inevitably changed. As a result, the input / output voltage gain of the converter is reduced, making it difficult to match the output voltage required by the load.

FIG. 1 is a circuit diagram of a conventional cascade boost-LLC resonant converter, and FIG. 2 is a graph showing an input / output gain according to an example of the converter of FIG.

As shown in FIG. 1, a conventional cascaded boost-LLC resonant converter comprises a boost converter 1 and an LLC resonant converter 2 connected in series. Here, for convenience of explanation, the input voltage Vi, the output voltage Vo, and the output power Po are set to 12V, 12V, and 10W, respectively, and the frequency of the LLC resonant converter 2 is set to about 130 kHz 2, the leakage inductance Lr and the magnetizing inductance Lm of the primary-side transmission coil Tx of the transformer 3 change according to the distance between the transmission and reception coils Tx and Rx as shown in Fig. Output voltage gain of at least 0.21 to 1. At this time, in order to control the output voltage Vo of the final receiving end of the secondary side to 12V, the boost converter 1 provided at the front stage boosts the input voltage Vi of 12V to vary the link voltage, As shown in FIG.

However, since the voltage gain of the LLC resonant converter varies greatly from 0.21 to 1 depending on the distance of the transmitting and receiving coils, the output voltage Vo) to 12V, the link voltage (Vlink) has to be varied from 12V to 75V in a very wide range. Considering the actual operation margin, the link voltage should be increased up to 76V. Therefore, even if the input voltage Vi is as low as 12V, when the charging distance between the transmitting and receiving coils is long, the link voltage and the voltage stress of the semiconductor device become very high. Therefore, the manufacturing cost is inevitably increased, It is disadvantageous to obtain high efficiency because it is difficult to use. In particular, as shown in the circuit diagram of FIG. 1, since the boost converter 1 and the LLC resonant converter 2 are composed of a two-stage power stage connected in series, the overall circuit size increases and is disadvantageous in price. Which is disadvantageous for high efficiency acquisition due to connection.

FIG. 3 is a circuit diagram of a conventional resonant tank variable LLC resonant converter, and FIG. 4 is a graph showing an input / output gain according to an example of the converter of FIG.

3, in the case of the conventional resonant tank variable LLC resonant converter, the conventional boost converter 4 and the LLC resonant converter 5 are constituted by a two-stage power stage connected in series and the transmission coil Tx of the transformer 6 The voltage gain is increased by connecting the variable capacitor bank 7 in which a plurality of series pairs of the auxiliary capacitor and the switch are connected in parallel to each other to vary the number of the resonance capacitors Cr substantially. That is, by decreasing or increasing the number of capacitors connected in parallel with the resonance capacitor Cr according to the coupling coefficient, the equivalent resonance capacitor is reduced by turning off the switch in series with the auxiliary capacitor of the variable capacitor bank 6 when the coupling coefficient is low The voltage gain of the LLC resonant converter can be varied as shown in FIG. 1, it is easy to ensure a high voltage gain, and the link voltage (Vlink) is not high, which is advantageous in terms of voltage stress of the device.

However, in such a case, it is necessary to turn on / off each of the switches connected in series with the plurality of auxiliary capacitors according to the coupling coefficient, so that the continuous operation is not possible, so that a sudden change in the coupling coefficient and a serious transient state There is a problem. In addition, as shown in Fig. 1, the power conversion efficiency is low due to the two-stage power stage.

As described above, in the case of a resonant converter for wireless power transmission applied to a wireless charger, an LLC resonant type topology is generally used as a transmitter converter in the related art. As the distance between the transmission coil Tx and the reception coil Rx becomes longer, The coupling coefficient is decreased, so that the leakage inductance of the transmitting coil increases and the magnetizing inductance decreases. Also, the inductance component fluctuating due to the change in the distance between the coils causes resonant tank fluctuation of the LLC resonant converter, thereby reducing the input / output voltage gain between the transmitting end and the receiving end and reducing the amount of transmitted power. There is a problem.

Korean Patent Publication No. 10-0691854 Korean Patent Publication No. 10-1377121

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a resonance type converter for wireless power transmission, in which a capacitor of a resonance tank has a current And the output voltage is controlled to be constant by injecting or discharging the current-injection type resonance type converter.

It is a further object of the present invention to provide a current injection type resonance type converter in which the entire circuit uses a full bridge type topology and is composed of only one power stage and has a high power conversion efficiency and a simple circuit configuration.

The current injection type resonance type converter according to the present invention includes a first switch M 1 and a second switch M 2 connected in parallel to an input voltage and connected in series to each other, A current injection circuit for injecting or discharging a current into the capacitor Cr; A resonant converter including the resonant tank and including a third switch M3 and a fourth switch M4 serially connected to each other; A transformer for transmitting the voltage supplied from the resonant converter to the secondary-side receiving coil from the primary-side transmitting coil; And a control unit for controlling operation of the resonant converter and the current injection circuit, wherein when the input / output voltage gain is greater than a preset reference value, the control unit controls the resonant capacitor Cr so that the current is injected into the resonant capacitor Cr of the resonant tank And controls the switching operation of the first to fourth switches (M1 to M4). When an input / output voltage gain smaller than the reference value is required, the first to fourth switches (M1 to M4).

In the present invention, the current injection circuit is connected to one side of the primary coil of the transformer through an inductor La and a capacitor Ca connected in series to each other at a first midpoint of the first and second switches.

In the resonant converter of the present invention, the second midpoint of the third and fourth switches is connected to the other side of the primary coil of the transformer through the resonant inductor (Lr) of the resonant tank.

In the present invention, the controller may control the switching operation of the first and second switches of the current injection circuit so that the output voltage of the receiving coil of the transformer is controlled to be a predetermined voltage, Causing the current to be injected or discharged into the capacitor.

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In the present invention, the control unit turns on the first switch and the third switch and turns off the second switch and the fourth switch so that the current based on the input voltage is applied to the first switch, the inductor La, Is supplied to the resonant capacitor through the first switch (Ca) and the current is supplied to the resonant capacitor through the third switch, the resonant inductor (Lr), and the primary coil of the transformer, The currents generated by the resonant converter are added to each other to flow together into the resonant capacitor to increase the current injection amount of the resonant capacitor.

In the present invention, the controller turns off the first switch and the third switch, turns on the second switch and the fourth switch, and the current based on the voltage stored in the resonance capacitor is applied to the inductor La. The capacitor Ca, and the second switch, and at the same time, the current flows through the primary coil, the resonant inductor Lr, and the fourth switch of the transformer.

In the present invention, the control unit turns on the second switch and the third switch and turns off the first switch and the fourth switch so that the current due to the input voltage flows through the third switch, the resonant inductor Lr) is supplied to the resonance capacitor through the transmission coil of the transformer, and a current due to the voltage charged in the resonance capacitor flows through the inductor La, the capacitor Ca and the second switch to cause the discharge, The current generated in the circuit and the current generated by the resonant converter cancel each other and flow into the resonant capacitor to reduce the current injection amount of the resonant capacitor.

In the present invention, the controller turns off the second switch and the third switch, turns on the first switch and the fourth switch, and the current based on the input voltage is supplied to the first switch, the inductor La ), And is supplied to the resonance capacitor through the capacitor Ca, and at the same time, the current due to the voltage stored in the resonance capacitor flows through the primary coil, the resonance inductor Lr, and the fourth switch of the transformer.

In the present invention, the switching of the first to fourth switches is set to a duty ratio of 50%, and the control unit controls the first to fourth switches so that each of the legs of the current- And controls the switching operation of the switch.

The current injection type resonance type converter according to the present invention injects or discharges an appropriate current into the capacitor of the resonance tank in order to cope with the change of the resonance tank or the output voltage according to the variation of the input / The output voltage can be controlled to be constant.

Further, in the current injection type resonance type converter according to the present invention, since the entire circuit uses the full bridge type topology, the zero voltage switching of all the switches can be performed through the phase shift driving, thereby minimizing the loss occurring in switching

In addition, the current injection type resonance type converter according to the present invention is advantageous in that the power conversion efficiency is high, the circuit configuration is simple, and the manufacturing cost is low because it is constituted by only one power terminal.

Also, the current injection type resonance type converter according to the present invention can be applied not only to wireless power transmission, but also to a power conversion converter for a general power circuit.

1 is a circuit diagram of a conventional cascade boost-LLC resonance type converter,
FIG. 2 is a graph illustrating input and output gains according to one example in the converter of FIG. 1;
3 is a circuit diagram of a conventional resonant tank variable LLC resonant converter,
4 is a graph illustrating input and output gains according to one example in the converter of FIG. 3;
5 is an overall circuit diagram of a current injection type resonance type converter according to an embodiment of the present invention,
6 is a diagram showing a switching operation signal of each switch of the current injection type resonance type converter according to the embodiment of the present invention,
FIG. 7 is a graph showing an output voltage graph according to a phase difference between a leading leg and a lagging leg when the current injection type resonant converter according to the embodiment of the present invention is operated by a phase shift method,
8 is a current flow diagram according to the operation of the current injection type resonance converter for increasing the current injection amount according to the embodiment of the present invention,
9 is a current flow diagram according to an operation of a current injection type resonance type converter for reducing a current injection amount according to an embodiment of the present invention,
10 is a graph showing a comparison between a resonance voltage according to a capacitance change of a resonance capacitor and a resonance voltage according to a current injection size in a fixed resonance capacitor according to an embodiment of the present invention,
FIG. 11 is a conceptual diagram of charging / discharging of a resonant capacitor when injecting and discharging a current by an external current source into a resonant capacitor of a resonant converter according to an embodiment of the present invention;
12 is a graph showing the resonance voltage in the resonance capacitor according to charge / discharge of FIG. 11,
13 is a graph of simulation results for verifying a current injection type resonant converter according to the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In the following description of the embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the difference that the embodiments of the present invention are not conclusive.

In describing the components of the embodiment of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, Quot; may be "connected," "coupled," or "connected. &Quot;

5 is a circuit diagram of a current injection type resonance type converter according to an embodiment of the present invention.

5, the current injection type resonance type converter according to the embodiment of the present invention includes a current injection circuit 110 connected in parallel to an input voltage Vi, a resonance type converter A transformer 130 connected to an output terminal of the resonant converter 120 to transmit a voltage to a secondary side and a current injection circuit 110 according to a secondary output voltage Vo of the transformer 130. [ And a control unit 140 for controlling the switching of the internal switches of the resonant converter 120.

The current injection circuit 110 includes a first switch M 1 and a second switch M 2 that are connected in series to each other and the first switch M 1 and the second switch M 2 are connected to the input voltage Vi They are connected in parallel. The first intermediate point N1 of the first and second switches M1 and M2 is connected to the primary coil of the transformer 130 via the inductor La and the capacitor Ca connected in series to each other, (Tx). Current is applied to the transmission coil Tx of the transformer 130 by the switching operation of the first switch M1 and the second switch M2.

The resonant converter 120 includes a third switch M3 and a fourth switch M4 which are connected in parallel to the current injection circuit 110 and are connected in series to each other. The second midpoint N2 of the position M4 is connected to the other side of the primary coil of the transformer 130, that is, the transmission coil Tx, through the resonant inductor Lr. Current is applied to the other side of the transmission coil Tx of the transformer 130 by the switching operation of the third and fourth switches M3 and M4. The resonant capacitor Cr of the resonant converter 120 is connected to one side of the transmission coil Tx to constitute the resonant tank 121 together with the resonant inductor Lr to generate resonance. In an embodiment of the present invention, the resonant converter 120 may be implemented, for example, with an LLC resonant converter. However, the present invention is not limited to this, and any circuit can be applied as long as it is a resonant converter that generates resonance by a switching operation in each switch of the internal half bridge circuit including the resonance tank.

The transformer 130 transfers the voltage due to the current applied from the resonant converter 120 to the secondary side as the primary voltage. The output voltage Vo is output to the secondary side load voltage output terminal of the transformer 130. The voltage delivered from the primary to the secondary is determined by the turns ratio of the transformer 130.

The control unit 140 controls the first and second switches M1 and M2 of the current injection circuit 110 to resonate with the secondary coil of the transformer 130 according to the output voltage Vo induced in the receiving coil Rx. Type converter 120 and the third and fourth switches M3 and M4, respectively. In particular, the controller 140 controls the switching operation of the first and second switches M1 and M2 of the current injection circuit 110 so that the output voltage Vo of the transformer 130 is controlled to be constant And a current is injected into the resonance capacitor (Cr) in the resonance type converter (120). Preferably, the controller 140 controls the switching operations of the first to fourth switches M1 to M4 according to the magnitude of the load connected to the secondary side of the transformer 130. [ More preferably, the switching operation of the first to fourth switches M1 to M4 is appropriately controlled in accordance with the request of the input / output voltage gain of the converter 100 according to the output voltage Vo required in the load. Specifically, when an input / output voltage gain greater than a predetermined reference value is requested, the controller 140 operates the first to fourth switches M1 to M4 so that the current is injected into the resonance capacitor Cr by the input voltage Vi. The first to fourth switches M1 to M4 are operated so that the amount of current injection is increased in the resonance capacitor Cr and conversely when the input / output gain is smaller than the reference value, the amount of current injection is reduced in the resonance capacitor Cr .

In the current injection type resonant converter 100 according to the present invention, the duty ratio of the switching driving signals of the first to fourth switches M1 to M4 is fixed at 50% as shown in FIG. 6, So that the switching operation of the first switch Ml through the fourth switch M4 can be realized. In this case, it is possible to obtain an additional advantage of ensuring zero voltage switching of all the switches M1 to M4. That is, as shown in FIG. 7, when the circuit of the converter 100 according to the present invention is operated by the phase shift method, the larger the phase difference between the leading leg and the lagging leg is, The input / output voltage gain is decreased. When the phase difference is 0 °, the maximum value is shown. When the phase difference is 180 °, the minimum value is shown.

FIG. 8 is a current flow diagram according to the operation of the current injection type resonance type converter for increasing the current injection amount according to the embodiment of the present invention, and FIG. 9 is a graph showing a current injection type resonance type converter for reducing the amount of current injection according to the embodiment of the present invention. Fig.

Hereinafter, the operation of the current injection type resonance converter 100 according to the embodiment of the present invention will be described in detail with reference to FIGS. 8 and 9. FIG.

FIG. 8 shows an operation circuit diagram for increasing the amount of current injected into the resonance capacitor Cr when a large input / output voltage gain is required depending on the load. 8A, the charging mode is a mode in which the controller 140 turns on the first switch M1 and the third switch M3 and turns on the second switch M2 and the fourth switch M4 Is turned off. Thereby, a current by the input voltage Vi is supplied to the resonance capacitor Cr through the first switch Ml, the inductor La and the capacitor Ca, and at the same time, the current also flows through the third switch M3, And is supplied to the resonance capacitor Cr through the inductor Lr and the primary coil Tx of the transformer 130. [ This increases the current injection amount of the resonant capacitor Cr by causing the current generated in the current injection circuit 110 and the current generated by the resonant converter 120 to be added together and flow into the resonant capacitor Cr will be. Thus, the voltage of the resonant capacitor Cr and the final input / output voltage gain can be increased. 8 (b), in the discharge mode, the controller 140 turns off the first switch M1 and the third switch M3 and turns off the second switch M2 and the fourth switch M4 On. Thus, a current due to the electrostatic voltage stored in the resonance capacitor Cr flows through the inductor La, the capacitor Ca, and the second switch M2 to discharge the current. At the same time, the current flows through the primary coil of the transformer 130 (Tx), the resonance inductor (Lr), and the fourth switch (M4).

9 is an operational circuit diagram for reducing the amount of current injection into the resonant capacitor Cr when a small input / output gain is required depending on the load. 9A, the charging mode is a mode in which the controller 140 turns on the second switch M2 and the third switch M3 and turns on the first switch Ml and the fourth switch M4 Is turned off. As a result, the current due to the input voltage Vi is supplied to the resonance capacitor Cr through the third switch M3, the resonance inductor Lr, and the primary coil Tx of the transformer 130, Cr flows through the inductor La, the capacitor Ca, and the second switch M2 to generate a discharge. This causes the current generated in the current injection circuit 110 and the current generated by the resonant converter 120 to cancel each other and flow into the resonant capacitor Cr to reduce the current injection amount of the resonant capacitor Cr will be. Thus, the voltage of the resonant capacitor Cr and the final input / output voltage gain can be reduced. 9 (b), in the discharge mode, the controller 140 turns off the second switch M2 and the third switch M3 and turns off the first switch M1 and the fourth switch M4 On. As a result, the current due to the input voltage Vi is supplied to the resonance capacitor Cr through the first switch Ml, the inductor La and the capacitor Ca, and at the same time, the current due to the voltage stored in the resonance capacitor Cr The primary coil Tx of the transformer 130, the resonant inductor Lr, and the fourth switch M4.

As described above, the effect of injecting a current into the resonant capacitor Cr of the resonant converter 120 appears similar to the effect of increasing the equivalent capacitance. Hereinafter, the simulation results will be described.

10 is a graph showing a comparison of resonance voltages according to a capacitance change of a resonance capacitor according to an embodiment of the present invention and a magnitude of a current injected into a fixed resonance capacitor. As shown in FIG. 10, the smaller the capacitance of the resonant capacitor Cr is, the more the resonant voltage point is increased. Similarly, when the resonant capacitor Cr varies the current injected in a fixed state, However, it can be seen that the effect similar to the voltage fluctuation due to the variation of the capacitance is obtained.

This is also seen from simulation results of injecting a current into the resonant capacitor Cr as shown in Figs. 11 and 12. Fig. FIG. 11 is a conceptual diagram illustrating charging / discharging of a resonant capacitor when a current is injected and discharged by an external current source into a resonant capacitor of a half bridge resonant converter according to an embodiment of the present invention. FIG. 4 is a graph showing the resonance voltage of the resonance capacitor Cr according to the first embodiment of the present invention. FIG.

11 shows a circuit diagram of a current injection type resonance type converter 100 according to the present invention in which a current source 10 is used in place of the current injection circuit 110 to apply a voltage to a resonance capacitor Cr of the resonance type converter 120 A simulation circuit diagram for injecting a current is shown. In FIG. 11A, the current source 10 is connected to apply a current to the resonant capacitor Cr, and in FIG. 11B, the current source 10 is connected to emit a current from the resonant capacitor Cr.

11 (a), the current generated by the resonant converter 120 and the current generated by the current source 10 are added to inject more current into the resonant capacitor Cr, In the discharge mode shown in FIG. 11 (b), the voltage stored in the resonant capacitor Cr is discharged by the current source 10 connected in the opposite direction to the closed circuit.

In this case, when a large current is injected into the resonant capacitor Cr using the external current source 10 as shown in FIG. 12, the effect of reducing the equivalent capacitance by increasing the voltage of the resonant capacitor Cr is obtained. The voltage of the resonance capacitor Cr is decreased and the equivalent capacitance is increased.

According to this principle, in the present invention, a current injection circuit 110 for injecting and discharging a current into and from the resonance capacitor Cr is connected to the front end of the resonance type converter 120, A current is injected into the resonance capacitor Cr to be charged or discharged to be discharged, so that the output voltage Vo is controlled to be constant.

< Experimental Example >

In order to verify the validity of the current injection type resonance converter 100 according to the experimental example of the present invention, a simulation was performed using a PSIM simulation tool. The input and output specifications and conditions used in these simulations are shown in Table 1 below.

Item Specifications (Conditions) Input voltage (Vi) 12V Output voltage (Vo) 12V Output power (Po) 10W Switching frequency 130 kHz The resonant capacitor (Cr) 500 ㎋ Transmission coil (Tx, Rx) 10:12 If the distance between the sending and receiving coils is relatively close Resonant inductor Lr, 1 μH The magnetizing inductor (Lm) 5 μH If the distance between the transmitting and receiving coils is relatively long Resonant inductor Lr, 5 μH The magnetizing inductor (Lm) 1 μH

13 shows the simulation result. 13A shows a case where the distance between the transmitting and receiving coils Tx and Rx is short and the magnetic coupling coefficient between the two coils Tx and Rx becomes large so that the leakage inductance of the resonance inductor Lr is small and the magnetizing inductance of the magnetizing inductor Lm is And the simulation results for the large case are shown. As shown in the figure, the LLC resonance shows a very stable waveform, and the zero-voltage switching of all the switches M1 to M4 is guaranteed due to the phase shift operation. 13B shows a case where the distance between the transmitting and receiving coils Tx and Rx is large and the magnetic coupling coefficient between the coils Tx and Rx is small and the resonance inductor Lr has a large leakage inductance and the magnetizing inductance of the magnetizing inductor Lm is The simulation results for the small case are shown. As shown in the figure, also in this case, the LLC resonance shows a very stable waveform, and the zero voltage switching of all the switches M1 to M4 is guaranteed due to the phase shift operation.

As described above, the current injection type resonance type converter 100 according to the embodiment of the present invention includes a current injection circuit (not shown) in front of the resonance type converter 120 so that the current can be injected into and discharged from the resonance capacitor Cr of the resonance type converter 120. [ A suitable current is injected or discharged to the resonance capacitor Cr of the resonance tank 121 in order to cope with a change in the output voltage according to the change of the resonance tank 121 of the resonance type converter 120. [ Thus, the output voltage can be controlled constantly even when the magnetic coupling degree according to the transmission distance change between the transmission and reception coils (Tx, Rx) varies in the wireless power transmission device such as the wireless charger, and the whole circuit is configured as a full bridge type topology The zero voltage switching of all of the switches M1 to M4 of the current injection circuit 110 and the resonant converter 120 can be performed through the phase shift driving, thereby minimizing the loss occurring during switching. In addition, since the converter 100 according to the present invention is composed of only one power terminal, there is an advantage that the power conversion efficiency is high and the circuit configuration is simple. In particular, since the present invention can be applied not only to wireless power transmission but also to a power conversion converter for a one-sided power supply circuit, it can acquire a technology superior in the field of acquiring proprietary technology related to wireless power transmission of high performance and high reliability.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. That is, within the scope of the present invention, all of the components may be selectively coupled to one or more of them. Furthermore, the terms "comprises", "comprising", or "having" described above mean that a component can be implanted unless otherwise specifically stated, But should be construed as including other elements. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Commonly used terms, such as predefined terms, should be interpreted to be consistent with the contextual meanings of the related art, and are not to be construed as ideal or overly formal, unless expressly defined to the contrary.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

110: current injection circuit 120: resonant converter
121: Resonant tank 130: Transformer
140: Control part Cr: Resonant capacitor
Lr: resonant inductor Lm: magnetizing inductor

Claims (10)

A first switch M1 and a second switch M2 which are connected in parallel to the input voltage and are connected in series to each other and are connected to the resonance capacitor Cr of the resonance tank to vary the input / Injection circuit;
A resonant converter including the resonant tank and including a third switch M3 and a fourth switch M4 serially connected to each other;
A transformer for transmitting the voltage supplied from the resonant converter to the secondary-side receiving coil from the primary-side transmitting coil; And
And a control unit for controlling operations of the resonant converter and the current injection circuit,
Wherein,
And controls the switching operations of the first to fourth switches (M1 to M4) so that a current is injected into the resonance capacitor (Cr) of the resonance tank when an input / output voltage gain greater than a predetermined reference value is required, And controls the switching operations of the first to fourth switches (M1 to M4) so that the amount of current injection is reduced in the resonance capacitor (Cr) when an input / output voltage gain is required. The semiconductor integrated circuit according to claim 1,
The first intermediate point N1 of the first switch M1 and the second switch M2 is connected to one side of the transmission coil of the primary side of the transformer through an inductor La and a capacitor Ca connected in series to each other. Injection type resonant converter. The resonance type converter according to claim 2,
The second intermediate point N2 of the third switch M3 and the fourth switch M4 is connected to the other side of the primary coil of the transformer through the resonant inductor Lr of the resonant tank, Type converter. 4. The apparatus of claim 3,
The switching operation of the first and second switches (M1, M2) of the current injection circuit is controlled so that the output voltage of the receiving coil of the transformer is constantly controlled to a predetermined voltage, thereby generating a resonance capacitor in the resonance tank Cr), the current is injected or discharged. delete The method of claim 3,
The control unit turns on the first switch M1 and the third switch M3 and turns off the second switch M2 and the fourth switch M4 so that the current by the input voltage Is supplied to the resonance capacitor (Cr) through the first switch (M1), the inductor (La), and the capacitor (Ca), and the current is supplied to the third switch (M3), the resonance inductor (Lr) The current generated in the current injection circuit and the current generated by the resonant converter are added to each other to flow together into the resonant capacitor Cr so as to be supplied to the resonant capacitor Cr, Current injection type resonance type converter. The method according to claim 6,
The control unit turns off the first switch Ml and the third switch M3 and turns on the second switch M2 and the fourth switch M4 to turn on the resonance capacitor Cr A current due to the stored voltage flows through the inductor La, the capacitor Ca and the second switch M2 to discharge the current, and the current flows through the primary coil, the resonant inductor Lr, And flows through the switch M4 to discharge the current. The method of claim 3,
The control unit turns on the second switch M2 and the third switch M3 and turns off the first switch Ml and the fourth switch M4 so that the current by the input voltage A current due to the voltage charged in the resonance capacitor Cr is supplied to the resonance capacitor Cr through the third switch M3, the resonance inductor Lr and the primary side transmission coil of the transformer, The capacitor Ca and the second switch M2 so that the current generated in the current injection circuit and the current generated by the resonant converter cancel each other and flow into the resonant capacitor Cr So as to reduce the current injection amount of the resonance capacitor (Cr). 9. The method of claim 8,
The control unit turns off the second switch M2 and the third switch M3 and turns on the first switch Ml and the fourth switch M4 so that the current due to the input voltage The current supplied to the resonant capacitor Cr through the first switch M1, the inductor La and the capacitor Ca and the current due to the voltage stored in the resonant capacitor Cr is supplied to the primary coil of the transformer, The resonance inductor Lr and the fourth switch M4 to cause a discharge to occur. The method according to claim 1,
Wherein the switching of the first to fourth switches (M1 to M4) is set to a duty ratio of 50%, and the control unit controls the first to the fourth switches (M1 to M4) so that each of the legs 4 resonance type converter for controlling the switching operation of the switches (M1 to M4).

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