TW202010218A - Low-energy-consumption and high-frequency wireless charging system for lithium battery capable of tuning charging curve to achieve Class-E wireless fast charging for lithium battery - Google Patents

Abstract

The present invention relates to a low-energy-consumption and high-frequency wireless charging system for lithium battery. The main structure of the present invention comprises a power supply module. The power supply module is cascaded with a first resonance unit. The first resonance unit is electrically connected with a tuning module. The tuning module comprises a first shunting unit and a second resonance unit that are electrically connected to the first resonance unit. The first shunting unit is electrically connected with a third resonance unit and a rectification module. The third resonance unit is connected in parallel with the rectification module. The rectification module is electrically connected with a voltage stabilizing module. The voltage stabilizing module is connected with a power storage element in parallel. The power storage element is connected with a grounding portion. With the aforementioned system structure, the tuning module may be used to enable the power storage element to achieve a charging curve with better efficiency during charging, so as to achieve the effect of Class-E wireless fast charging.

Description

Low-energy high-frequency wireless charging system for lithium battery

The present invention is to provide a low-energy high-frequency wireless charging system for lithium batteries, in particular to a low-energy high-frequency wireless charging system for lithium batteries that has a better charging curve and can directly charge lithium batteries quickly and wirelessly.

In recent years, wireless power transmission (WPT) via inductive resonance coupling has become popular, and various electronic devices (eg, mobile phones, notebook computers, wearable devices, medical implanted devices) and even electric vehicles are charged. For WPT operating at high power in kilohertz (kHz), rapid progress has been made in coil design, compensation topology, and control strategies. At the same time, in order to reduce the size and weight of the WPT system, it is best to further increase the operating frequency to a few megahertz (MHz), such as 6.78 and 13.56 MHz. The higher operating frequency will help to improve the spatial freedom, that is, the longer transmission distance and the higher tolerance of the coupling coil alignment, which is particularly beneficial for charging mobile devices.

However, when operating at an operating frequency of MHz, the power capability of the switching equipment will be relatively insufficient. Currently, megahertz WPT is generally considered suitable for medium and low power applications. For MHz WPT, the use of traditional power amplifiers (PA) and rectifiers will produce high switching losses. Due to its soft switching characteristics, Class E power amplifiers and rectifiers are expected to become candidates for building high-efficiency MHz WPT systems. Among them, the class E power amplifier was applied to the MHz WPT system for the first time, and was improved due to its high efficiency and simple topology. Similarly, Class E rectifiers have also been proposed for high-frequency rectification.

About the application research in WPT. According to reports, at 800kHz operating frequency, the efficiency of the rectifier is as high as 94.43%. Therefore, the combination of a class E power amplifier and a rectifier (that is, a class E converter) is expected to achieve a high-efficiency wireless charging system that operates at MHz.

Due to its high energy density, lithium-ion batteries are now widely used in consumer electronic devices. The typical charging curve of lithium-ion batteries is usually composed of constant current (CC) mode and constant voltage (CV) mode. In order to extend the battery cycle life, The battery is first charged in CC mode. When its voltage reaches the standard value, the charging system enters CV mode, and the charging current drops rapidly. That is, the wireless charging system must accurately provide current and voltage according to a specific battery charging curve.

In practical applications, the charging configuration can be monitored by the input voltage control of the charging system, or the regulation circuit between the charger and the battery. In conventional E-type converters for WPT applications, the system parameters are only for a single specific operating condition The optimization is to fix the relative position of the coil and the final load. However, unlike the traditional constant resistance load, the battery voltage and current will change with the charging curve.

In addition, the input reactance of the class E rectifier cannot be ignored at MHz, and will change with the change of battery voltage and current. This obvious and changing input reactance of the class E rectifier increases the power loss and leads to high efficiency MHz E The design of wireless battery-like charging systems is complicated.

Due to the non-negligible and changing input reactance of the class E rectifier, these existing methods have been ineffective for the class E wireless charging system of wireless batteries.

Therefore, how to solve the above-mentioned conventional problems and deficiencies is the one where the applicant of the present invention and related manufacturers engaged in this industry are eager to study the direction of improvement.

Therefore, in view of the above-mentioned deficiencies, the inventor of the present invention has collected relevant information, evaluated and considered through multiple parties, and based on years of experience accumulated in this industry, through continuous trial and modification, began to design such a use of tuning module for The inventor of the invention can tune the lithium battery through the E-type wireless charging to achieve low power consumption and high efficiency, low energy consumption and high frequency wireless charging system.

The main purpose of the present invention is to add a first shunt unit and a second resonance unit to tune the charging curve of the lithium battery, so that the lithium battery can be directly charged with Class E wireless fast charging with low power loss and high charging efficiency.

To achieve the above object, the main structure of the present invention includes: a power supply module, a first resonance unit connected in series with the power supply module, a tuning module located on one side of the first resonance unit and electrically connected, and a tuning mode A second shunt unit electrically connected, a third resonance unit and a rectifier module electrically connected to one end of the second shunt unit, a voltage regulator module at one side electrically connected to the rectifier module, A power storage element connected in parallel with the voltage stabilizing module and a grounding portion connected to the side of the power storage element, wherein the tuning module includes a second resonance unit electrically connected to the first resonance unit and a first shunt unit.

With the above structure, the user can give power through the power supply module and tune the rectifier module through the first resonance unit and the third resonance unit to stabilize the current and return the current through the second shunt unit , Can make the current through the rectifier module have double the efficiency, and stabilize the voltage through the voltage regulator module to charge the storage element, and when the voltage in the storage element is charged to a certain level, it will be The constant current module is changed to a constant voltage module. At this time, the first shunt unit and the second resonance unit in the tuning module can be used for tuning, so that the storage element still has better charging when being charged by the constant voltage power supply. Curve to achieve the effect of quickly charging the storage element.

With the above technology, it is possible to break through the problem that conventional E-type wireless charging cannot quickly charge the lithium battery, and achieve the practical progress of the above advantages.

1‧‧‧Power supply module

2‧‧‧ First resonance unit

3‧‧‧Tuning module

31‧‧‧First shunt unit

32‧‧‧Second resonance unit

4‧‧‧Second shunt unit

51‧‧‧The third resonance unit

52‧‧‧Rectifier module

6‧‧‧ Voltage regulator module

7‧‧‧Power storage element

8‧‧‧Ground

91‧‧‧ Constant Voltage Module (CV Mode)

92‧‧‧Constant Current Module (CC Mode)

93‧‧‧Charging current

94‧‧‧Charging voltage

95‧‧‧Resistance Rout

96‧‧‧Output reactance Xout

97‧‧‧Resistance Rin

98‧‧‧Input reactance Xin

The first figure is a block diagram of a preferred embodiment of the present invention.

The second diagram is a current flow diagram of the preferred embodiment of the present invention.

The third graph is a charging efficiency graph of the preferred embodiment of the present invention.

The fourth diagram is a loss curve diagram of the preferred embodiment of the present invention.

The fifth figure is a schematic diagram of a class E wireless battery charging system according to a preferred embodiment of the present invention.

The sixth figure is a schematic diagram of a charging curve of a lithium battery according to a preferred embodiment of the present invention.

The seventh figure is a schematic diagram of the impedance of the preferred embodiment of the present invention.

The eighth figure is a schematic diagram of the coupling coil efficiency (η coil) of the preferred embodiment of the present invention.

The ninth figure is a schematic diagram of the input impedance of the preferred embodiment of the present invention.

Figure 10 is a schematic diagram of an LC matching network according to a preferred embodiment of the present invention.

Figure 11 is a block diagram of the relationship of the preferred embodiment of the present invention.

In order to achieve the above objectives and effects, the technical means and structure adopted by the present invention, the drawings and details of the preferred embodiments of the present invention are described in detail below. Their features and functions are as follows, so that they fully understand.

Please refer to the first figure, which is a block diagram of a preferred embodiment of the present invention. It can be clearly seen from the figure that the present invention includes: a power supply module 1, a first resonance unit 2, and a tuning module 3 , A second shunt unit 4, a third resonance unit 51, a rectifier module 52, a voltage stabilizing module 6, a power storage element 7, and a grounding portion 8.

The power supply module 1 is an inductor that receives power by wireless induction.

The first resonance unit 2 is connected in series with the power supply module 1, and the first resonance unit 2 is a capacitor.

The tuning module 3 is located at one side of the first resonance unit 2, and the tuning module 3 includes a second resonance unit 32 electrically connected to the first resonance unit 2 and a third resonance unit electrically connected to the first resonance unit 2 A shunt unit 31, the second resonance unit 32 is a capacitor (Capacitance), and the first shunt unit 31 is an inductor (Inductance).

One end of the second shunt unit 4 is electrically connected to the first shunt unit 31, and the second shunt unit 4 is an inductor.

The rectifier module 52 is electrically connected to the end of the first shunt unit 31 facing away from the first resonance unit 2.

The third resonance unit 51 is connected in parallel with the rectifier module 52, and the third resonance unit 51 is a capacitor.

The voltage stabilizing module 6 is electrically connected to one end of the rectifying module 52, and the voltage stabilizing module 6 is a voltage stabilizing capacitor.

The electricity storage element 7 is connected in parallel with the voltage stabilizing module 6, and the electricity storage element 7 is a DC battery.

The ground portion 8 is connected to one side of the power storage element 7.

Through the above description, the structure of this technology can be understood, and according to the corresponding cooperation of this structure, the tuning module 3 can be used to stabilize the curve during charging, thereby performing wireless fast charging, and the detailed explanation will be given below述说明。 Description.

Please also refer to the first to eleventh figures, which are block schematic diagrams to related block diagrams of preferred embodiments of the present invention. When the above components are configured, it can be clearly seen from the figures that users use Wireless electromagnetic waves are used to induce the power supply module 1 to supply power, and the first resonance unit 2 and the third resonance unit 51 tune the passing current to reduce electromagnetic interference (EMI), and the third resonance unit 51 can also Controlling the frequency of the rectifier module 52, thereby converting the AC power supply to a DC power supply, the voltage stabilizing module 6 can stabilize the voltage supplied to the storage element 7, so that the storage element 7 can be charged, and the first The second shunt unit 4 allows the return power to be reintroduced into the rectifier module 52 to enhance the current passing through the rectifier module 52, which can increase the charging efficiency.

When the voltage in the storage element 7 reaches a predetermined value, the constant current module (CC Mode) 92 will be changed to the constant voltage module (CV Mode) 91 as shown in the third figure, at this time the tuning can be used The second resonance unit 32 in the module 3 is tuned, and the current is re-introduced through the first shunt unit 31, so that the overall charging curve can be more stable, and will be as shown in the third figure. When the charging mode (L1) is changed from constant current module (CC Mode) 92 to constant voltage module (CV Mode) 91, its efficiency will decrease rapidly with time, so that fast charging cannot be performed. The invention (L2) will cooperate with the second resonance unit 32 through the first shunt unit 31 to make the overall charging curve change from the CC mode 92 to the CV mode 91, but it can still have The high-efficiency charging curve can also maintain similar low-efficiency losses as shown in the fourth figure, so that lithium batteries can be quickly charged with low power loss and high-efficiency Class E wireless charging.

The above charging mode is the charging performance generated by the E-type wireless battery charging system and the tuning module. The derivation techniques and formulas are as follows; please refer to the fifth figure for the conventional 6.78-MHz E Wireless battery charging system.

It consists of Class E PA, Class Coupling Coils, Class E rectifier and Lithium Batteries. Ltx and Lrx represent the transmitting and receiving coils respectively; rtx and rrx are the equivalent series resistance (ESR) of Ltx and Lrx; Ctx and Crx are the compensation capacitors; Zin is the input impedance of the coupling coil, and Zout is the input seen from the receiving coil Impedance; Vbat and Ibat are the battery voltage and charging current, respectively, and Vin is the output voltage.

The typical lithium battery charging mode is usually composed of two modes, namely constant voltage module (CV Mode) 92 and constant voltage module (CV Mode) 91. It is first expected that the wireless battery charging system will provide accurate charging current and voltage. In order to meet the required charging curve, refer to the sixth figure for a schematic diagram showing the charging curve of the lithium battery. In this charging curve, the constant charging current is 1μA, and the constant battery voltage is 16.8V, that is, the charging current 93 and charging voltage 94 curves are displayed, and the changes of the charging current 93 and charging voltage 94 will affect the values of Zout and Zin In turn, it affects the efficiency of the coupling coil and the class E power amplifier. Due to the highly nonlinear behavior of the class E rectifier when working in MHz, the resulting impact becomes more obvious in the MHz Class E wireless charging system.

If the well-known nonlinear radio frequency (RF) circuit simulation software is used to study the performance of the classic 6.78-MHz Class E wireless battery charging system, and during the test, a half-wave Class E rectifier is used and the following The same Class E rectifier was used in the analysis and experiment.

Please refer to the seventh figure, which shows the simulation results of the resistance Rout 95 and the output reactance Xout 96 with the charging curve Zout of the sixth figure. It can be seen that in the CV mode, the capacitance is the output reactance Xout 96 sharply Increase, and in conjunction with the eighth figure, it can be seen that this output reactance Xout 96 has a significant impact on the coupling coil efficiency η coil and power transmission capacity, which will rapidly reduce the efficiency η coil.

At the same time, referring to the ninth figure again, it is the simulation result of the input impedance of the coupling coil. Due to the increase in the output reactance Xout 96, the input impedance Zin of the resistor Rin 97 and the input reactance Xin 98 drops rapidly in the CV mode, and the low resistance of the input impedance Zin will cause the transmission coil Ltx, the transmission coil, etc. in the class E power amplifier Correction of series resistance rtx and component resistance produces high power losses. In addition, varying resistance Rin 9 7 and input reactance Xin 98 (ie, PA load) may have a negative effect.

As mentioned above, following the required battery charging curve will result in changes in impedance characteristics, and thus significantly affect the efficiency of the coupling coil and the class E power amplifier when operating at MHz, resulting in the complication of the class E wireless charging system. Please refer to the tenth figure, in order to mitigate the influence of the battery changing current and voltage change, an LC matching network (Matching Network) can be added to the classic Class E wireless charging system, which is the tuning module 3 of the present invention. The matching network (tuning module 3) is located between the coupling coils (Coupling coils) and the Class E rectifier. It improves the loading conditions of the coupling coils and Class E PA, and introduces new design freedom to optimize the overall system efficiency under battery charging characteristics. Among them, the compensation capacitance of the transmitting coil Ctx is absorbed into the class E PA (Class E PA). Among the series capacitors of C0, Ldc and Lf are the DC filter inductance of the class E power amplifier and rectifier, respectively, and Cs is the parallel capacitor of the class E power amplifier. Cr and Co are shunt capacitors and DC output capacitors of class E rectifiers. Ls and Cp are the series inductance (first shunt unit 31) and parallel capacitance (second resonance unit 32) of the LC matching network, respectively.

The above technology can be implemented with the following formula: The above formula is Formula 1, which is the relationship between efficiency η sys(t) and Ibat(t) and Vbat(t) in electromagnetic charging; and at a specific time (t), The output power Po of the charging system is: P _o ( t )= I _bat ( t ) V _bat ( t ).

Therefore, the total power loss Ploss at a specific time (t) is

可定 義為下列公式：

Here, η sys(t) can be calculated by substituting Ibat(t) and Vbat(t) into Equation 1. After optimization calculation, the charging configuration is evenly divided into N parts. Therefore, the average loss efficiency

Can be defined as the following formula:

然後可以經由Ls計算rLs的ESR

其中；Ls為第一分流單元31；Cr為第三諧振單元51；

為初始階段的電流值；ω為工作頻率；D為整流的工作週期；

為電池電壓也就是儲電元件7的電壓；

為充電時的電流； Xrec可經由Cr、

、及

決定； QLs是Ls的品質因數，注意，在下面的設計優化過程中給出候選Cr用於計算Ls。以下優化中的設計參數，電容器最終確定如下；x=[ C _S , C ₀ , C _rx , C _p , C _r ], 這裡x是一個向量。Cs和C0是E類PA的並聯和串聯電容器；Crx是接收線圈的補償電容(第一諧振單元2)；Cp是匹配網路的並聯電容器(第二諧振單元32)；Cr是E類整流器的並聯電容器(第三諧振單元51)；由於不可忽略的Xrec，Crx也被視為一個設計參數，在整個charing循環中進一步降低Xrec的影響。因此，與傳統設計不同，接收線圈的諧振在此不是預先假定的。 The purpose of the LC matching network is to improve the load conditions of the coupling coil. Ls should be designed to partially compensate for the non-negligible reactance in the input impedance of the Class E rectifier operating at MHz, which is:

Then the ESR of rLs can be calculated via Ls

Among them; Ls is the first shunt unit 31; Cr is the third resonance unit 51;

Is the current value in the initial stage; ω is the operating frequency; D is the rectification duty cycle;

The battery voltage is the voltage of the storage element 7;

Is the current when charging; Xrec can pass Cr,

,and

Decision; QLs is the quality factor of Ls. Note that the candidate Cr is given for calculating Ls in the following design optimization process. The following optimization of the design parameters, the capacitor finally determined as _{follows; x = [C S, C} 0, C rx, C p, C r], where x is a vector. Cs and C0 are parallel and series capacitors of class E PA; Crx is the compensation capacitor of the receiving coil (first resonance unit 2); Cp is the parallel capacitor of the matching network (second resonance unit 32); Cr is the class E rectifier Shunt capacitor (third resonance unit 51); due to non-negligible Xrec, Crx is also regarded as a design parameter, which further reduces the influence of Xrec throughout the charing cycle. Therefore, unlike the conventional design, the resonance of the receiving coil is not assumed in advance here.

The constant parameters (Pcon) in the optimized design of the wireless charging system are as follows

The problem of design optimization is expressed as follows

(x ^lower ,x ^upper ),

為X最小值時；

為平均功率損耗；X^lower和X^upper分別是X的下限和上限可行範圍；I和V代表已記錄的電池充電曲線。 st x

( x ^lower , x ^upper ),

When it is the minimum value of X;

It is the average power loss; X ^lower and X ^upper are the lower and upper feasible range of X respectively; I and V represent the recorded battery charging curve.

Ltx and Lrx represent the transmitting and receiving coils respectively; rtx and rrx are the equivalent series resistance (ESR) of Ltx and Lrx; Ctx and Crx are the compensation capacitors; therefore, the experimental results of the system efficiency can be derived through the above formula, and can be obtained Figure 11 is the relationship between the design parameters and constants and the battery charging curve. The inductance and ESR of the class E rectifier will be calculated through the variable X within a certain range and the I and V values given by the battery charging curve. Calculate the system power consumption through cooperation with a fixed variable Pcon.

However, the above is only the preferred embodiment of the present invention, and it does not limit the patent scope of the present invention. Therefore, all the simple modifications and equivalent structural changes caused by the description and drawings of the present invention should be the same. It is included in the patent scope of the present invention and is conjoined with Chen Ming.

Therefore, the key to improving the conventional technology of the low-energy high-frequency wireless charging system of the lithium battery of the present invention is:

The tuning module 3 is used to stabilize the charging curve. With a simple design, it achieves Class E wireless fast charging with low power loss and high efficiency charging of lithium batteries.

In summary, when the low-energy high-frequency wireless charging system of the lithium battery of the present invention is used, in order to indeed achieve its efficacy and purpose, the present invention is an invention with excellent practicability, which is in accordance with the application requirements of the invention patent , I file an application in accordance with the law, and I hope that the review committee will grant the invention as soon as possible to protect the applicant's hard work. If the bureau has any doubts, please send me a letter and give instructions. The applicant will try his best to cooperate and feel virtuous.

1‧‧‧Power supply module

2‧‧‧ First resonance unit

3‧‧‧Tuning module

31‧‧‧First shunt unit

32‧‧‧Second resonance unit

4‧‧‧Second shunt unit

51‧‧‧The third resonance unit

52‧‧‧Rectifier module

6‧‧‧ Voltage regulator module

7‧‧‧Power storage element

8‧‧‧Ground

Claims (6)

A low-energy high-frequency wireless charging system for lithium batteries mainly includes: a power supply module; a first resonance unit, the first resonance unit is connected in series with the power supply module; a tuning module, the tuning module is located in the The first resonance unit is at one side and is electrically connected to it, the tuning module includes a second resonance unit and a first shunt unit, the first shunt unit and the second resonance unit are electrically connected; a second shunt unit , One end of the second shunt unit is electrically connected to the first shunt unit to supply current return; a rectifier module, the rectifier module is located at one side of the first shunt unit and is electrically connected to the first shunt unit Sexual connection is used to adjust the current flow; a third resonance unit, the third resonance unit and the rectifier module in parallel, is used to control the frequency of the rectifier module; a voltage regulator module, the voltage regulator module One end is electrically connected to the rectifier module; an electric storage element, the electric storage element is connected in parallel with the voltage stabilizing module; and a grounding portion, the grounding portion is located at one side of the electric storage element, and The electrical components are electrically connected. The low energy consumption and high frequency wireless charging system for lithium batteries as described in item 1 of the patent scope, wherein the power supply module is a power supply provided by a wireless connection method. The low-power high-frequency wireless charging system for lithium batteries as described in item 1 of the patent scope, wherein the first resonance unit, the second resonance unit, and the third resonance unit are capacitors. The low energy consumption and high frequency wireless charging system for a lithium battery as described in item 1 of the patent scope, wherein the voltage stabilizing module includes at least one voltage stabilizing capacitor. The low-power high-frequency wireless charging system for lithium batteries as described in item 1 of the patent scope, wherein the first shunt unit and the second shunt unit are inductances. The low-energy high-frequency wireless charging system for lithium batteries as described in item 1 of the patent scope, wherein the power storage element is a DC battery.

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