KR101871772B1 - High power high voltage type wireless power receiver - Google Patents

Abstract

The wireless power transmission receiver of the present invention adjusts the load output in a voltage range lower than the maximum voltage of the resonance frequency, and is particularly advantageous for controlling the output of high voltage high power.

Description

Technical Field [0001] The present invention relates to a high power high voltage type wireless power receiver,

The present invention relates to a high power, high voltage wireless power transmission receiver. More specifically, the present invention relates to a receiver that branches a coil of a receiver to enable high power, high voltage wireless power transmission.

Current self resonance, magnetic induction type and RF method, and wireless charging and wireless power transmission method by using ultrasonic wave and optical are manufactured in a structure capable of transmission and reception of several to several tens of watts. Also, when a plurality of receivers (loads) are to be used in one transmitter, conventional techniques make and use receivers using relatively similar voltage and current levels.

     For example, if you look at current wireless power transmission technologies, you only need to have 5V (12V for fast charging) voltage to charge your smartphone. In addition, it is relatively easy to assume multiple use, and it is a tablet PC which is expressed by a large number of loads, and it is easy to charge the battery if it also holds only the voltage level of 5V (12V for fast charging).

In other words, in a wireless power transmission scheme, although the characteristics of multiple users in one transmitter structure appear to use different receivers (loads), actual implementations use multiple receivers (loads) with similar power or similar voltage levels Power transmission is possible.

In the conventional technique, a large output is generated in one transmitter to produce a desired power level or voltage level at the receiver. The basic configuration of the receiver is a combination of a coil and a capacitor, and a bridge rectification or other method, (buck converter or step-down) to generate the desired voltage and current, and the voltage is controlled by a feedback circuit, a zener diode, or the like.

By the way. Since the developed DC-DC converter or step-down integrated circuit is fabricated on the basis of an integrated circuit (IC), the level at which the IC receives and controls the voltage is limited.

The maximum input value of the IC of the present DC-DC converter is about 90V. Of course, there is a method to convert and receive the voltage of 90V or more, but the use of a transformer and the like are required, and the volume is increased, so that there is a limitation in practical use.

Also, if DC-DC converter is used at 5V by using a voltage of 90V or more, the voltage difference causes the efficiency drop due to heat generation and other losses.

Therefore, in order to simultaneously receive a product having a power level voltage level different from that of a single transmitter, it is necessary to basically assume a receiver requiring a large power voltage, and to increase the capacity of the transmitter accordingly. Conversely, in very small products that do not require large power voltage, high power voltage is not needed and only a small converter technology is needed.

Even if a small-sized converter is made at the same time, it is not easy to apply the current IC-based converter due to a large heat. Even if you implement this,

In the case where the receiving part of a product having a different power and voltage is close to each other in a structure in which a resonance circuit composed of LC is close, the voltage level of a product of a large power voltage is induced toward a small power voltage due to the magnetic induction phenomenon, And loss. In addition, due to the characteristics of wireless power, it is difficult to maintain the accurate power voltage at the desired position as the amount of change in the amount of power approaches the magnitude (the closer the power level is and the lower the farther away)

In order for each power to use multiple products in a single transmitter, a method is needed in which power corresponding to each power demand is supplied and maintained in any case.

There have been many attempts to generate a high-voltage, high-power power source through configuration changes of the receiver of the wireless power transmission device.

Korean Patent Laid-Open Publication No. 10-2016-0057278 discloses a technique in which first and second coils each of which surrounds another one are provided and a shielding member spaced apart along the circumference of one of the two coils is provided, 1 coil or a second coil or two coils at the same time. However, the patent mentions the number and arrangement of the coils, but does not disclose any structure or function associated with the circuitry of the receiver.

Korean Patent Laid-Open Publication No. 10-2013-0116230 discloses a technique of arranging two resonance coils and induction coils in a receiver, connecting induction coils to a rectifier, and maintaining or blocking power transmitted to the load Discloses a wireless power transmission system. However, the use of two coils in this patent is due to the self-resonant wireless power transmission, the use of a plurality of coils is optional in that a resonant coil is not required by the magnetic induction type, The configuration is limited in that there is no difference from the existing wireless power system.

Korean Patent Laid-Open Publication No. 10-2015-0134107 discloses a method of connecting a switch element to a capacitor of a receiver and opening a switch at a time when power is maximally stored in an inductor of a reception resonator, have. However, this patent has limitations in supplying high voltage power to the load and controlling power because it controls the power transfer by switching on / off operation and does not make any structural changes to the coil of the receiver.

Korean Patent Laid-Open Publication No. 10-2013-044647 discloses a reception power conversion apparatus for a resonance-type wireless charging system, in which a switch is connected to an LC circuit of a receiver, and an alternating- a free-wheeling path is formed, the output signal of the power conversion device is fed back, a level is detected, and a switching operation of the switching unit is controlled in accordance with the detected output level. However, this patent also has limitations in supplying high voltage power to the load and controlling power because it controls the power transfer by the switching on / off operation of the switching and does not make any structural change to the coil of the receiver.

 An object of the present invention is to provide a high-power, high-voltage wireless power transmission receiver capable of responding to a maximum resonant frequency in a high-power supply-demand situation and capable of supplying a voltage below a maximum allowable voltage smaller than a theoretical maximum voltage.

According to an aspect of the present invention, there is provided a wireless power transmission receiver comprising: a resonance combination unit including a coil and a capacitor connected in parallel to resonate with a transmitter; A control circuit connected in parallel to the coil of the resonance combining section and including a switch and a buffer capacitor; A detector for detecting a load voltage output from the resonance combining unit and supplied to the load; And a comparison determination unit for comparing the load voltage detected by the detection unit with a predetermined set value, wherein the predetermined set value is a maximum voltage set value, and when the detected load voltage reaches the maximum voltage set value, And the resonance frequency is mismatched so that the resonance frequency is different from the resonance frequency matched by the resonance frequency.

delete

delete

delete

The predetermined set value further includes a minimum voltage set value, and when the detected load voltage reaches the minimum voltage set value, the switch is turned off to match the resonance frequency of the resonance combining section with the resonance frequency of the transmitter.

The coil of the resonance combining unit includes a first coil and a second coil, and the first coil and the second coil may be connected by a bridge portion connecting the two coils.

The control circuit may be connected to at least one of the first coil and the second coil.

The bridge portion may be connected to the rectifying portion.

The first coil and the second coil are connected to the bridge portion by a link or a tab connecting the two coils.

The present invention also provides a method of controlling a wireless power transmission receiver, comprising the steps of: (a) receiving a load voltage (V) from a resonance combination unit comprising a coil and a capacitor connected in parallel to resonate with a transmitter and supply a voltage to a load of the receiver Detecting by the detecting unit a determination of whether or not the comparison voltage is equal to or greater than a predetermined minimum voltage set value; (b) if the step (a) is affirmative, supplying the load voltage to the load; (c) detecting the load voltage supplied to the load by the detection unit and determining whether the load voltage reaches a predetermined maximum voltage set value in the comparison determination unit; And (d) if the step (c) is affirmed, mismatching the resonance frequency of the resonance combining unit to a frequency different from the resonance frequency of the transmitter, wherein the step (d) And the switch is turned on when the switch of the control circuit including the switch and the buffer capacitor is turned on.

delete

After the step (d), canceling the step of mismatching when the load voltage reaches a predetermined minimum voltage set value.

The present invention has an effect that the output voltage can be stably controlled below the maximum allowable voltage smaller than the theoretical maximum voltage when it is difficult to obtain and control the power in accordance with the finding of the maximum voltage and the resonance frequency achieving the maximum efficiency .

The present invention is simple and economical to manufacture because the voltage output to the load can be controlled by branching the coil of the receiver to the bridge section and adding a control circuit of simple configuration.

The present invention is a new technology of the future which is expected to increase the demand for a high power high voltage load output, which is a great technical value.

1 is a perspective view illustrating a coil according to an embodiment of the present invention.
2 is a perspective view illustrating a coil according to another embodiment of the present invention.
Fig. 3 is a circuit showing the coil of Fig. 2 connected to the rectification part. Fig.
4 is a partial circuit diagram of a receiver including a control circuit according to an embodiment of the present invention.
5 is a circuit diagram of a switch according to an embodiment of the present invention.
6 is a graph illustrating a method of controlling a load output according to an embodiment of the present invention.
7 is a circuit diagram of a receiver including a control circuit according to an embodiment of the present invention.
8 is a flow chart illustrating the steps of controlling a high power, high voltage wireless power transmission method according to an embodiment of 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 the drawings, like reference numerals are used to denote like elements in the drawings, even if they are shown in different drawings. In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present disclosure rather unclear.

In describing the constituent elements of the present embodiment, the first, second, a), b) and the like can be used. Such a code is intended to distinguish the constituent element from other constituent elements, and the nature of the constituent element, the order or the order of the constituent element is not limited by the code. It is also to be understood that when an element is referred to as being "comprising" or "comprising", it should be understood that it does not exclude other elements unless explicitly stated to the contrary, do.

Currently, most wireless power technologies are working to find and maintain maximum resonance points. This is a method of changing L or changing C in a wireless power transmission technique using L and C. The required control technology is appropriate for the basic circuit characteristics that guarantee the maximum power at the maximum resonance point, but this does not apply to all the wireless power transmission technologies. It is not necessary to search for the maximum resonance point to generate and use the voltage.

The power before reaching the maximum resonance and the power when the maximum resonance point is exceeded are also used to receive the power and use it for a proper load.

According to the embodiment of the present invention, there is provided a high-power, high-voltage wireless power transmission receiver capable of responding to a maximum resonant frequency in a high-power supply situation and capable of supplying a voltage below a maximum allowable voltage lower than a theoretical maximum voltage.

A coil L according to an embodiment of the present invention for receiving a high voltage from a transmitter in a wireless power transmission apparatus will be described with reference to Figs. 1 and 2. Fig.

1, the coil L includes a rectangular first coil L1 and a second coil L2 having curved corners. Between the first coil L1 and the second coil L2 is connected a tap-like link to one side of the rectifier diode. The configuration of the coil 1 is advantageous for increasing the inductance of the coil to generate a high voltage high power signal.

Although the link for bridging the first coil L1 and the second coil L2 is formed by a straight line, the shape and the length are not limited, and the link connecting the first coil L1 and the second coil L2 Any position other than the central portion of the coil may be crosslinked.

The terminal A is the end of the first coil L1 and the terminal B is connected to the end of the second coil L2 and one of the terminals is connected to the other end of the rectifying part.

 Another feature according to the embodiment of the present invention is to control a high power high voltage and therefore it can be applied to a mismatching circuit connected to a link or a bridge of the first coil L1 and the second coil L2 .

2 shows an example of a coil L for this purpose. The coil L includes a first coil L1 and a second coil L2 which are circular or square. A bridge is formed by providing a link between the first coil L1 and the second coil L2.

From the bridge portion, the line T can be extended and connected to one side of the rectifying portion. The line T can branch at any position of the bridge portion of the first coil L1 and the second coil L2.

Fig. 3 is a circuit showing the coil L of Fig. 2 connected to the rectifying section 10. Fig.

The resonant combination section that receives power from a transmitter (not shown) includes a parallel-connected capacitor C1 and a coil L (L1, L2). The bridge portion of the first coil L1 and the second coil L2 is connected to one side of the rectifying portion. The rectifying section 10 includes four diodes. The rectifying unit 10 is shown by way of example, and any arbitrary configuration such as a bridge rectifier, a Schottky or a high-speed recovery diode can be adopted.

One of the terminals A and C extending from the coils L, L1 and L2 is connected to one side of the rectifying part 10. [ The rectifying section 10 is subsequently connected to the rectifying capacitor and the load output.

Next, an embodiment of the present invention for controlling a high power high voltage will be described.

Fig. 4 shows the structure of a receiver including the control circuit 1 of the present invention.

The control circuit 1 includes a switch S and a buffer capacitor 2. 3, the bridge portion of the first coil L1 and the second coil L2 is also connected to the control circuit 1, and the buffer capacitor 2 is connected in series to the switch S. The control circuit 1 may be connected in parallel to the second coil L2, but may be connected to the first coil L1.

The buffer capacitor 2 serves to prevent the maximum voltage from being induced by changing the resonance point matched by the resonance combination part.

The switch S may be a field effect transistor (FET), an insulated gate bipolar transistor (IGBT), or a digital or analog relay. The matching of the resonance points can be changed by a hard switching method in which only the switches are used alone and the internal ground is directly formed and the coil L or the capacitor C1 is connected to the ground. However, there is a fear of malfunction due to surge and noise Since there is a danger of a momentary voltage drop, it is desirable to utilize the capacitor 2 as an impact buffer.

In the case of using an n-channel MOSFET (metal-oxide-semiconductor FET) as the switch S, the zener diode Mz in addition to the gate Mg, the drain Md and the source Ms, Is connected to the source Ms and then the ground Mg 'is formed as the switch S, it is advantageous in that the malfunction is prevented by performing the correct operation of On and OFF.

In Fig. 4, when the switch S is OFF, the current flows in the direction shown by the solid line arrows and is supplied to the rectifying section 10. [ In this case, a high-voltage high-power output can be obtained owing to the overlapping bridge structure of the coils L, L1 and L2. The control circuit 1 is disconnected from the main circuit of the transmitter, and substantially becomes an equivalent circuit of Fig.

4, when the switch S is ON, the second coil L2, the switch S, and the buffer capacitor 2, as indicated by the dotted line in addition to the supply current to the rectifying section 10 of the solid line, Is further formed. Due to the loop current, the second coil L2 and the buffer capitality 2 form another second LC combination.

This second LC combining part affects the resonance combining part composed of the capacitor C1 and the coils L (L1, L2). For example, the value of total inductance and capacitance can be changed to reduce the load voltage applied to the load of the receiver.

That is, when the switch S is turned on and a loop current is generated in a state where the resonance combination part resonates with the receiver at the resonance frequency, the value of the capacitor increases due to the buffer capacitor 2, To a resonant frequency other than the resonant frequency. Then, a voltage less than the maximum voltage generated in the ideal resonance state can be supplied to the load of the receiver.

The advantage of this control is that it is difficult to supply and control the power to find the exact resonant frequency that achieves the maximum voltage and maximum efficiency and to control the output voltage stably below the maximum allowable voltage that is less than the theoretical maximum voltage .

On the other hand, in FIG. 4, even when the switch S is ON, the voltage current supplied to the rectifying unit 10 continues to exist, and the load voltage tends to increase even when the voltage S is not the resonant frequency. Therefore, the capacitance value of the buffer capacitor 2 needs to be designed so that the final output voltage does not exceed the maximum allowable voltage and the voltage value drops after the maximum allowable voltage is maintained for a certain time, so as to cancel this inherent increase.

The buffer capacitor 2 is technically significant in that the operating frequency is a configuration that converts the theoretical resonant frequency state at the receiver to a more practical and useful frequency state.

Here, 'operating frequency' refers to the frequency actually being driven when power is supplied to the load of the receiver. The operating frequency according to an embodiment of the present invention may be a resonance frequency of the matching state, but may be a frequency different from the resonance frequency of the mismatching state.

Thus, when the switch S is ON, the control circuit 1 changes the output of the matched resonance frequency to make an output under the mismatching state frequency. In this respect, the control circuit 1 of the present invention can be regarded as a mismatching forming circuit. The control circuit 1 is activated when the switch is ON. It is also possible to constitute one or more control circuits. It will be appreciated that the control circuit 1 may be connected to the terminal A, that is, to be associated with the first coil L1, and may be connected to both terminals A and C. In this regard, although the terminal A is shown as being not connected to the other parts of the receiver in Fig. 4, other variations are possible.

The control of the output voltage will be described with reference to Fig. 6 based on the description of Fig.

In FIG. 6, the abscissa is time (t) and the ordinate is voltage (V) at the output supplied to the load of the receiver. VL is the minimum voltage setting, and VF is the highest voltage supplied at the theoretical resonant frequency. The control of the voltage point corresponding to the accurate resonance frequency is sensitive and difficult. Especially when the peak voltage output is not needed, the maximum voltage set value VM is set so that the output voltage range to the load is set to the minimum voltage set value VL and the maximum And a region R1 between the voltage set value VM. In this case, a region R2 between the theoretical maximum voltage VF and the maximum voltage setting value VM is actually a range excluded from the output, and is indicated by a two-dot chain line in Fig.

The maximum voltage set value (VL) is, for example, a difference between the resonance frequency of 3 dB on both sides of the resonance frequency point, that is, the difference between the frequencies of the resonance frequency and the resonance frequency divided by 3 dB bandwidth. Value.

 It can be set to a voltage corresponding to a frequency having a gain for dividing the resonance frequency by the 3 dB bandwidth.

In Fig. 6, when the voltage rises to reach the minimum voltage set value VL, the output to the load is started. As soon as the voltage rises and reaches the maximum voltage set value VM, the switch S of Fig. 4 is turned ON. Then, as described above, the operating frequency transitions to a frequency slightly different from the preset maximum resonance frequency, and the output voltage maintains the maximum voltage set value VM for a predetermined time.

The length of the sustain period (P) depends on various variables such as the capacity of the buffer capacitor (2) and the absolute value of the voltage. As the buffer capacitor 2 is charged, the voltage that remains constant as the above-described operation of the second LC combination continues, drops gradually and reaches the minimum voltage set value VL.

Then, the switch S of FIG. 4 is returned to the OFF state again. The loop voltage current disappears and only the voltage current flowing in the rectification section 10 exists and the resonance combination section composed of the capacitor C1 and the coils L and L1 and L2 starts to drive again toward the resonance frequency, do.

Since this cycle is repeated periodically, the output voltage is continuously controlled in the range of the region R1, so that stable adjustment is possible while maintaining the property of the sawtooth square wave.

From the above description, in order to control the receiver according to the embodiment of the present invention, the load voltage is always detected, the detected voltage is compared with the maximum and minimum voltage set values, and the control for turning ON / OFF the switch S according to the result Is required.

Fig. 7 is an overall configuration diagram of a receiver of the present invention based on the above description.

The control unit 30 according to the embodiment of the present invention in addition to the resonance combination unit, the control circuit 1 and the rectification unit 10 includes a detection unit 32 that detects the load voltage that is output 20 from the resonance combination unit and supplied to the load And a comparison determination unit 34 for comparing the load voltage detected by the detection unit 32 with a maximum voltage setting value VM and a minimum voltage setting value VL.

Fig. 8 is a flowchart showing an operation procedure of the control section 30. Fig.

First, it is determined whether the load voltage detected by the detector 32 is equal to or greater than the minimum voltage set value VL (S10). If so, control goes to step S12 to supply an output to the load.

It is determined whether or not the load voltage detected by the detecting section 32 rises and is equal to or higher than the maximum voltage setting value VM in step S14. If the determination is affirmative, the switch is turned on in step S16 and the control circuit 1 is switched to the mismatching forming circuit . The reduced load voltage is supplied to the load (S18), and it is determined whether the voltage value falls to reach the minimum voltage set value VL (S20). If the voltage is lowered, the switch is turned off (S22) ). Since the control circuit 1 is disconnected from the main circuit of the transmitter, the output is supplied to the load while the mismatch forming function is released or stopped, and the voltage gradually rises. By repeating this control, the output voltage can be maintained in a useful stable range, as described above.

It is also possible that the step S10 is omitted at the beginning and the switch is turned on at the maximum value without detecting the minimum set value, and may be turned off when the minimum value is detected.

While this 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, but, on the contrary, is intended to cover various modifications and alternative embodiments. For example, the terms " high voltage " and " high power " are relative concepts as technology advances, and the basic principle of the present invention is equally applicable to relatively small " small voltage "

It is obvious that the scope of the present invention is limited to the same or equivalent scope as the following claims.

(L): coil (L1): first coil (L2): second coil (T): line
(10): rectifying section (1): control circuit (2): buffer capacitor
(S): switch (20): output (30): control unit (32): detection unit (34)

Claims (11)

In a wireless power transmission receiver,
A resonance combining unit including a coil and a capacitor connected in parallel for resonance coupling with a transmitter;
A control circuit connected in parallel to the coil of the resonance combining section and including a switch and a buffer capacitor;
A detector for detecting a load voltage output from the resonance combining unit and supplied to the load; And
And a comparison determination unit for comparing the load voltage detected by the detection unit with a predetermined set value,
Wherein the predetermined set value is a maximum voltage set value, and when the detected load voltage reaches the maximum voltage set value, the switch is turned on to mismatch the resonance frequency such that the resonance frequency is different from the resonance frequency matched by the resonance combination section Receiver.
delete delete delete The method according to claim 1,
Wherein the predetermined set value further includes a minimum voltage set value and when the detected load voltage reaches the minimum voltage set value, the switch is turned off to match the resonance frequency of the resonance combining section with the resonance frequency of the transmitter receiving set.
The method according to claim 1,
Wherein the coil of the resonant combination portion includes a first coil and a second coil, and the first coil and the second coil are connected to a bridge portion connecting the two coils.
The method according to claim 6,
Wherein the control circuit is connected to at least one of the first coil or the second coil. The method according to claim 6,
And the bridge portion is connected to the rectifying portion. The method according to claim 6,
Wherein the first coil and the second coil are connected to the bridge portion by a link or a tab connecting the two coils.
A method for controlling a wireless power transmission receiver,
(a) a load voltage supplied to a load from a resonance combination unit composed of a coil and a capacitor connected in parallel so as to supply a voltage to the load of the receiver by resonance coupling with the transmitter is detected by a detection unit, Determining whether the voltage is equal to or higher than a voltage set value;
(b) if the step (a) is affirmative, supplying the load voltage to the load;
(c) detecting the load voltage supplied to the load by the detection unit and determining whether the load voltage reaches a predetermined maximum voltage set value in the comparison determination unit; And
(d) if the step (c) is affirmed, mismatching the resonance frequency of the resonance combining unit to a frequency different from the resonance frequency of the transmitter,
Wherein the step (d) is performed when the switch of the control circuit including the switch and the buffer capacitor is turned on, the switch being connected in parallel to the resonance combining unit.
11. The method of claim 10,
Further comprising, after step (d), releasing the step of mismatching when the load voltage reaches a predetermined minimum voltage setpoint.

Images