CN111711250A - Wireless charging system and output voltage adjusting method thereof - Google Patents

Abstract

The present invention relates to a wireless charging system, including: the information detection module is used for detecting the relative positions of a receiving end coil and a transmitting end coil in the electric energy transmission module; the electric energy transmission module is used for wirelessly transmitting the electric energy supplied by the power grid to a receiving end of the wireless charging system to charge the battery; and the transmitting end compensation element switching control system is used for judging the working modes of the switching controller according to the detected position information of the receiving end coil, wherein the working modes comprise a power supply starting mode and a power supply stopping mode. The invention also discloses an output voltage adjusting method of the wireless charging system. Based on the standard LCC compensation topology and the improved LCC compensation topology, the invention uses the control switch to switch the corresponding compensation inductor or capacitor, realizes the adjustment of the output voltage gain of the system and improves the stability of the output voltage of the system.

Description

Wireless charging system and output voltage adjusting method thereof

Technical Field

The invention relates to the technical field of wireless charging, in particular to a wireless charging system and an output voltage adjusting method thereof.

Background

Wireless charging is a novel battery charging technology, and wireless transmission of electric energy is mainly realized through electromagnetic coupling between transmitting and receiving end coils. Compared with the traditional wired charging mode, the wireless charging mode has the advantages of convenience, safety, reliability, no weather influence and the like, so that the wireless charging mode has wide application prospect in the fields of portable electronic equipment, medical implant equipment, electric automobiles and the like. With the development of battery technology, wireless charging technology has become a research hotspot and is gradually commercialized.

In order to meet the requirement of constant voltage output characteristics, the current wireless charging system can keep the stability of the output voltage of the receiving end as long as the system input voltage, the inductance of the coil of the transmitting and receiving end and the parameter value of the compensating element are unchanged. However, in the actual charging process, the degree of coupling between the system transmitting and receiving coils is reduced due to the coil offset, which affects the system output characteristics. Therefore, in order to maintain a stable output voltage, the magnitude and phase of the input voltage at the transmitting end are generally adjusted by the control module, or the operating frequency of the system is adjusted, but this will reduce the energy transmission efficiency of the system to some extent, resulting in excessive energy loss.

Disclosure of Invention

The invention aims to provide a wireless charging system which can improve the stability of the output voltage of the system, ensure that the wireless charging system always works in a resonance state and improve the energy transmission efficiency.

In order to achieve the purpose, the invention adopts the following technical scheme: a wireless charging system, comprising:

the information detection module is used for detecting the relative positions of a receiving end coil and a transmitting end coil in the electric energy transmission module, detecting the input current of a transmitting end, and transmitting offset signals of the receiving end coil and the transmitting end coil and input current signals in the transmitting end coil to a switching controller of a transmitting end compensation element switching control system;

the electric energy transmission module is used for wirelessly transmitting the electric energy supplied by the power grid to a receiving end of the wireless charging system to charge the battery;

the transmitting end compensation element switching control system is used for judging the working mode of the switching controller according to the detected position information of the receiving end coil, and the working mode comprises a power supply starting mode and a power supply stopping mode; in the process of starting and operating the switching controller, according to a detected signal of current input at the transmitting end, judging the switching mode of a numerical gear of the compensating element at the transmitting end, wherein the switching mode comprises gear-up operation and gear-down operation, sending a corresponding gear switching instruction to the compensating element parameter regulator, and according to the instruction signal, the parameter regulator controls the switch by controlling the adjustable inductor, the capacitor or the compensating element to switch the numerical value of the compensating inductor or the capacitor at the transmitting end and accesses the corresponding compensating inductor or the capacitor to the electric energy transmission module.

The information detection module includes:

the coil position detection device consists of two position sensors which are arranged at the front side and the rear side of the transmitting end coil and are used for detecting the motion state information of the electric energy pickup coil and transmitting the offset between the electric energy pickup coil at the receiving end and the center of the transmitting end power supply guide rail coil to the switching controller;

and the current sensor is used for detecting the input current of the coil at the transmitting end of the system and transmitting the current signal to the switching controller.

The power transmission module includes:

the transmitting end electric energy conversion circuit consists of a rectifying circuit, a Boost type Power Factor Correction (PFC) circuit, a Buck voltage regulating circuit and a high-frequency inverter circuit; the alternating current transformer is used for converting alternating current from a power grid into alternating current with controllable voltage and frequency and injecting the alternating current into a transmitting end coil;

the receiving end electric energy conversion circuit consists of a rectifying filter circuit and a DC-DC circuit and is used for converting alternating current induced in a receiving end coil into direct current and providing stable charging voltage for a battery load through the control of the DC-DC circuit;

the receiving and transmitting end coil system comprises a receiving end coil and a transmitting end coil, and realizes wireless transmission of energy in an air gap through electromagnetic coupling of the transmitting end coil and the receiving end coil;

the receiving and transmitting end compensation network module is used for improving wireless charging efficiency, system active power and power factors and comprises a transmitting end compensation network and a receiving end compensation network, wherein the transmitting end compensation network adopts a standard LCC compensation topology or an improved LCC compensation topology, and the receiving end compensation network adopts a series compensation topology;

the standard LCC compensation topology is divided into two types, one type is the standard LCC compensation topology adopting adjustable inductance and capacitance, wherein the adjustable inductance is L'_{0 tone}The capacitor is C'_{0 tone}、C’_{1 tone}(ii) a The other is a standard LCC compensation topology employing a compensation element control switch, wherein the compensation element control switch is S'_A、S’_BAnd S'_C(ii) a The improved LCC compensation topology is divided into two types, one type is the improved LCC compensation topology adopting an adjustable capacitor, wherein the adjustable capacitor is C_{tone of t}、C_{0 tone}、C_{1 tone}(ii) a Another is an improved LCC compensation topology employing a compensation element controlled switch, wherein the compensation element controlled switch includes S_A、S_BAnd S_C(ii) a When the transmitting terminal compensation network adopts a standard LCC compensation topology, the standard LCC compensation topology and the series compensation topology form a standard LCC-S compensation topology together; when the transmitting terminal compensation network adopts the improved LCC compensation topology, the improved LCC compensation topology and the series compensation topology jointly form an improved LCC-S compensation topology;

the transmitting end compensation element switching control system comprises:

the switching controller is used for switching the compensation element connected into the main circuit of the transmitting terminal according to the change of the input current of the transmitting terminal so as to achieve the aim of adjusting the compensation inductance or capacitance value;

and the compensation element parameter regulator is used for executing the instruction of the switching controller, controlling the adjustable inductor, the capacitor or the compensation element control switch, carrying out numerical value switching on the corresponding transmitting end compensation inductor or capacitor, and connecting the corresponding compensation inductor or capacitor with the transmitting end electric energy conversion circuit and the transmitting end coil to finish electric energy transmission of the transmitting end.

The standard LCC-S compensation topology of the standard LCC compensation topology adopting the compensation element to control the switch comprises a compensation inductor L₀A first compensation capacitor C of the transmitting terminal₀A second compensation capacitor C of the transmitting terminal₁And a receiving end compensation capacitor C₂(ii) a Wherein the compensation inductance L₀In the form of a matrix inductor and controlling switch S'_AConnected to each other through a switching control switch S'_ARealize the compensation inductance L₀The two values together form a compensation inductance which can be switched and is marked as L_{0 switch}(ii) a First compensation capacitor C of transmitting terminal₀In the form of a matrix capacitor and controlling switch S'_BConnected to each other through a switching control switch S'_BRealize the first compensation capacitor C₀The two together form a compensation capacitor, denoted as C, which can be switched on and off_{0 switch}(ii) a Second compensation capacitor C of transmitting terminal₁In the form of a matrix capacitor and controlling switch S'_CConnected to each other through a switching control switch S'_CTo C₁The two together form a compensation capacitor, denoted as C, which can be switched on and off_{1 switch}(ii) a Compensating inductance L capable of switching₀Is connected with an input voltage U_inPositive pole of (2), compensation inductance L capable of switching_{0 switch}The other end of the capacitor is respectively connected with a compensating capacitor C capable of switching_{0 switch}The compensating capacitor C can be switched on and off_{1 switch}Are connected at one end, and C_{1 switch}Another end of and a transmitting end coil L₁Are connected in series at one end, and C_{0 switch}Another end, transmitting end coil L₁The other ends of the two ends are connected with an input voltage U_inNegative pole, transmitting end coil L₁And a receiving end coil L₂Are electromagnetically coupled, the mutual inductance of the coupling coil is M, and the receiving end coil L₂Receiving end compensation capacitor C₂Equivalent load R_LForm a series loop with a system input current of I_inThe current in the coil at the transmitting end is I₁In a series circuit in which the receiving-side coil is locatedCurrent is I₂The voltage across the equivalent load is U_out；

The standard LCC-S compensation topology adopting the standard LCC compensation topology with adjustable inductance and capacitance comprises a transmitting end compensation inductance L'_{0 tone}And a first compensation capacitor C 'at a transmitting end'_{0 tone}And a second compensation capacitor C 'of a transmitting end'_{1 tone}And a receiving end compensation capacitor C₂(ii) a Power supply U_inThe positive electrode and the transmitting end of the transformer compensate inductance L'_{0 tone}Is connected with a transmitting end to compensate inductance L'_{0 tone}The other end of the first capacitor is respectively connected with a first compensation capacitor C 'of the transmitting end'_{0 tone}And a second compensation capacitor C 'of a transmitting end'_{1 tone}Is connected with a transmitting end and is provided with a second compensation capacitor C'_{1 tone}Another end of and a transmitting end coil L₁Is connected in series with a first compensation capacitor C 'at the transmitting end'_{0 tone}Another end, transmitting end coil L₁The other ends of the two ends are connected with an input voltage U_inNegative pole, transmitting end coil L₁And a receiving end coil L₂Are electromagnetically coupled, the mutual inductance of the coupling coil is M, and the receiving end coil L₂Receiving end compensation capacitor C₂Equivalent load R_LForm a series loop with a system input current of I_inThe current in the coil at the transmitting end is I₁The current in the series loop in which the receiving end coil is located is I₂The voltage across the equivalent load is U_out。

The improved LCC-S compensation topology of the improved LCC compensation topology using compensation element control switch comprises a transmitting end compensation inductance L₀A first compensation capacitor C of the transmitting terminal_tA second compensation capacitor C of the transmitting terminal₀A third compensation capacitor C of the transmitting terminal₁And a receiving end compensation capacitor C₂(ii) a Wherein, the first compensation capacitor C of the transmitting terminal_tIn the form of a matrix inductor and associated control switch S_AConnected by a changeover control switch S_ARealize the first compensation capacitor C_tThe two together form a compensation capacitor, denoted as C, which can be switched on and off_t-switch(ii) a Second compensation capacitor C of transmitting terminal₀In the form of matrix capacitors, and controlSwitch S_BConnected by a changeover control switch S_BTo C₀The values of (A) and (B) are switched, and the values form a compensation capacitor which can be switched on and off, C_{0 switch}(ii) a Third compensation capacitor C of transmitting terminal₁In the form of a matrix capacitor and associated control switch S_CConnected by a changeover control switch S_CTo C₁The values of (A) and (B) are switched, and the values form a compensation capacitor which can be switched on and off, C_{1 switch}(ii) a Transmitting terminal compensation inductance L₀Is connected with an input voltage U_inThe positive electrode of (2), the transmitting terminal compensation inductance L₀And the other end of the capacitor C and a compensation capacitor C capable of switching_t-switchAre connected to one end of C_t-switchThe other end of the capacitor is respectively connected with a compensating capacitor C capable of switching_{0 switch}The compensating capacitor C can be switched on and off_{1 switch}Are connected at one end, and C_{1 switch}Another end of and a transmitting end coil L₁Are connected in series at one end, and C_{0 switch}Another end, transmitting end coil L₁The other ends of the two ends are connected with an input voltage U_inNegative pole, transmitting end coil L₁And a receiving end coil L₂Are electromagnetically coupled, the mutual inductance of the coupling coil is M, and the receiving end coil L₂Receiving end compensation capacitor C₂Equivalent load R_LForming a series loop with a current I in the coil at the transmitting end₁The current in the series loop in which the receiving end coil is located is I₂The voltage across the equivalent load is U_out；

The improved LCC-S compensation topology adopting the improved LCC compensation topology of the adjustable capacitor comprises a transmitting end compensation inductor L₀A first compensation capacitor C of the transmitting terminal_{tone of t}A second compensation capacitor C of the transmitting terminal_{0 tone}A third compensation capacitor C of the transmitting terminal_{1 tone}And a receiving end compensation capacitor C₂(ii) a Transmitting terminal compensation inductance L₀Is connected with an input voltage U_inThe positive electrode of (2), the transmitting terminal compensation inductance L₀Another end of the first compensation inductor C and the transmitting end_{tone of t}Is connected with one end of the first compensation inductor C at the transmitting end_{tone of t}The other end of the first compensating capacitor is respectively connected with the transmitting endContainer C_{0 tone}A third compensation capacitor C of the transmitting terminal_{1 tone}Is connected with one end of the first compensating capacitor C_{1 tone}Another end of and a transmitting end coil L₁One end of the first compensating capacitor C is connected in series, and the transmitting end of the first compensating capacitor C is connected in series₀Another end, transmitting end coil L₁The other ends of the two ends are connected with an input voltage U_inNegative pole, transmitting end coil L₁And a receiving end coil L₂Are electromagnetically coupled, the mutual inductance of the coupling coil is M, and the receiving end coil L₂Receiving end compensation capacitor C₂Equivalent load R_LForming a series loop with a current I in the coil at the transmitting end₁The current in the series loop in which the receiving end coil is located is I₂The voltage across the equivalent load is U_out。

Another object of the present invention is to provide an output voltage adjusting method of a wireless charging system, the method comprising the following sequential steps:

(1) establishing a circuit model of the wireless charging system based on the standard LCC-S compensation topology and the improved LCC-S compensation topology respectively, analyzing the relation between the voltage gain of the wireless charging system of the standard LCC-S compensation topology and the parameter value of a compensation element, and analyzing the relation between the parameter of the compensation element and the inductance of a coil when the system works in a resonance state; analyzing the relationship between the voltage gain of the wireless charging system of the improved LCC-S compensation topology and the parameter value of the compensation element, and analyzing the relationship between the parameter of the compensation element and the coil inductance when the system works in a resonance state; the standard LCC-S compensation topology means that a transmitting end compensation network adopts a standard LCC compensation topology, and a receiving end compensation network adopts a series compensation topology; the improved LCC-S compensation topology means that the transmitting end compensation network adopts the improved LCC compensation topology, and the receiving end compensation network adopts the series compensation topology;

(2) according to different compensation topologies adopted by a system transmitting end, respectively designing a numerical value gear of a transmitting end compensation element parameter of the wireless charging system with a standard LCC-S compensation topology and a numerical value gear of a transmitting end compensation element parameter of the wireless charging system with an improved LCC-S compensation topology according to the relation between corresponding voltage gain and the compensation element parameter value;

(3) designing a corresponding switching controller according to a compensation topology adopted by a system transmitting end: firstly, transmitting a collected central position signal of a receiving and transmitting end coil to a switching controller so as to start/stop supplying power to a transmitting end coil; secondly, inputting the collected input current signal of the transmitting end into a switching controller, and calculating the current output voltage gain according to the input voltage value of the transmitting end, the coil inductance and the load resistance value; then, transmitting the obtained voltage gain signal to a switching controller, comparing a standard voltage gain value with an actual voltage gain signal fed back in real time, determining a target value gear of the compensation element, and sending a compensation element target value gear signal to a compensation element parameter regulator; and finally, the compensation element parameter regulator sends out an instruction for switching the compensation element parameters, and controls the adjustable inductor, the capacitor or the compensation element control switch to switch the corresponding compensation inductor or capacitance value, so as to realize the control of the compensation element parameter regulation of the wireless charging system.

Analyzing the relationship between the voltage gain of the wireless charging system with the improved LCC-S compensation topology and the parameter value of the compensation element in the step (1), and analyzing the relationship between the parameter of the compensation element and the inductance of the coil when the system works in a resonance state specifically means that:

output voltage gain H_uThe relation between the parameters of the compensation element and the inductance of the coil is as follows:

where ω is the system operating frequency, L₀Compensation of inductance for the transmitting end, C_tIs equal to L₀A compensation capacitor connected in series; λ 1/(ω)²L₀C_t) To compensate for capacitance C_tAdjusting the coefficient; in the improved LCC-S compensation topology, if the system input voltage and the series compensation inductance L₀If the relationship is kept unchanged, the relationship is simplified as follows:

H_uL₀/M₀＝μ·p

wherein, mu is 1/(1-lambda) couplingCompensation coefficient of mutual inductance variation of combined coil, p being M/M₀For mutual inductance variation coefficient, M and M₀The mutual inductance of the coupling coils at the current position and the position opposite to the coil at the receiving and transmitting end is respectively;

analyzing the relationship between the voltage gain of the wireless charging system with the standard LCC-S compensation topology and the parameter value of the compensation element in the step (1), and analyzing the relationship between the parameter of the compensation element and the coil inductance when the system works in the resonance state specifically means:

output voltage gain H_uThe relation between the parameters of the compensation element and the inductance of the coil is as follows:

wherein M is the mutual inductance of the coupling coil at the current position, L₀The inductance is compensated for the transmitting end.

The step (2) of designing the numerical value gear of the parameter of the transmitting end compensation element of the wireless charging system with the improved LCC-S compensation topology specifically comprises the following steps:

when the mutual inductance fluctuation of the coupling coil is caused by the coil offset of the transmitting and receiving ends, the mutual inductance value at the current position is assumed as follows: m_i＝p_iM₀，p_iThe mutual inductance variation coefficient is used for adjusting the output voltage gain of the system by changing the compensation capacitance value of the transmitting end; let the capacitance C of the current gear_ti＝q_iC₀At the initial resonant frequency, C_tThe variation of the value is expressed as a capacitance adjustment coefficient lambda_iAnd mutual inductance variation compensation coefficient mu_iThe change of (2):

wherein i is the gear at which the compensation element is currently located, and q is the capacitor C_tA scaling factor of (c); meanwhile, in order to satisfy the resonance condition, the capacitor C needs to be synchronously adjusted_{0 change}And C_{1 change}Comprises the following steps:

thus, reference is made to the capacitance C₁And a capacitor C_tiAre connected in series to obtain a capacitor C_{1 change}(ii) a Through the mutual inductance variation coefficient p of the coupling coil_iAnd mutual inductance variation compensation coefficient mu_iDetermining the required value gear i of the compensating element so as to obtain the compensating capacitor C_t、C_{0 change}And C_{1 change}The numerical values of the gears; wherein, C_{0 change}、C_{1 change}Compensating capacitors C for the transmitting terminals, respectively₀、C₁The value after gear adjustment;

the step (2) of designing the numerical value gear of the parameter of the transmitting end compensation element of the wireless charging system with the standard LCC-S compensation topology specifically comprises the following steps:

when the mutual inductance fluctuation of the coupling coil is caused by the coil offset of the transmitting and receiving ends, the mutual inductance value at the current position is assumed as follows: m_i＝p_iM₀，p_iThe mutual inductance variation coefficient is obtained, and the system output voltage gain is as follows: h_u＝p_iM₀/L_{0 change}(ii) a Wherein L is_{0 change}Compensating the inductance L for the transmitting end₀The value after gear adjustment; at this time, L can be adjusted by changing the compensation inductance value of the transmitting terminal_{0 to i}＝a_iL₀Thereby adjusting the output voltage gain of the system:

wherein i is a compensation capacitor C_{0 change}The value of a is the compensation inductance L_{0 change}The adjustment coefficient of (2) represents the mutual inductance value of the coupling coil of the current gear and the mutual inductance value L of the initial moment₀The ratio of (A) to (B); meanwhile, in order to make the system work in a resonance state, the compensation capacitor C needs to be synchronously adjusted_{0 change}、C_{1 change}：

Thus, the electricity will be initiatedContainer C₁And a capacitor C_String＝C₀/(1-p) are connected in series to obtain a capacitor C_{1 change}(ii) a Through the mutual inductance variation coefficient p of the coupling coil_iAnd a voltage gain, determining the required value gear i of the compensation element, thereby obtaining the compensation inductance L_{0 change}And a capacitor C_{0 change}、C_{1 change}The numerical values of the respective gears.

In step (3), designing the transmission-side compensation element switching controller according to the improved LCC-S compensation topology specifically includes the following steps:

3a1) starting control:

in the process that the receiving end coil gradually approaches to the transmitting end coil, when the position sensor arranged on the front end side of the transmitting end coil detects that the receiving end coil arrives, the position sensor sends a starting signal and transmits the starting signal to the switching controller to control the initial compensation network to be connected into the main circuit, and the corresponding transmitting end coil is in a power supply state; when the position sensor arranged on the rear end side of the transmitting end coil detects that the receiving end coil is completely separated, the coil position sensor sends out a termination signal and transmits the termination signal to the switching controller, at the moment, the compensation network is cut off, and the corresponding transmitting end coil is in an idle state;

3b1) system input current detection and feedback control:

in the improved LCC-S compensation topology, the relationship between the system input current and the voltage gain is:

wherein, ξ_i＝H_u/H_u0＝μ_ip_iFor the system output voltage gain factor, H_u0Is a reference value of voltage gain, and in the current detection and switching control procedure, the voltage gain coefficient when the receiving and transmitting end coil is over against is used as the reference value ξ₀Order ξ_i＝ξ₀＝1；

3c1) The parameter switching of the compensation element controlled in the step (3) is specifically as follows: determining the rise of the value of the compensating element according to the target value gear signal of the compensating element sent by the switching controllerA shift/downshift operation; the adjustable capacitor or the compensation element control switch is controlled by the compensation element parameter regulator to switch the value of the compensation capacitor at the transmitting end, and the compensation capacitor C of the corresponding value gear is switched_t、C_{0 change}、C_{1 change}The power transmission module is connected to the power transmission module;

in step (3), designing the transmitting terminal compensation element switching controller according to the standard LCC-S compensation topology specifically includes the following steps:

3a2) starting control:

in the process that the receiving end coil gradually approaches to the transmitting end coil, when the position sensor arranged on the front end side of the transmitting end coil detects that the receiving end coil arrives, the position sensor sends a starting signal and transmits the starting signal to the switching controller to control the initial compensation network to be connected into the main circuit, and the corresponding transmitting end coil is in a power supply state; when the position sensor arranged on the rear end side of the transmitting end coil detects that the receiving end coil is completely separated, the coil position sensor sends out a termination signal and transmits the termination signal to the switching controller, at the moment, the compensation network is cut off, and the corresponding transmitting end coil is in an idle state;

3b2) system input current detection and feedback control link

In the LCC-S compensation topology, the relationship between the system input current and the voltage gain is as follows:

wherein, κ_i＝H_u/H_u0＝p_i/a_iFor the system output voltage gain factor, H_u0A reference value that is a voltage gain; in the current detection and switching control link, the voltage gain coefficient when the transmitting and receiving end coil is aligned is used as the reference value k₀Let κ be_i＝κ₀＝1；

3c2) The compensation element switch controlled in the step (3) is specifically: determining the upshifting/downshifting operation of the value of the compensating element according to the compensating element target value gear signal sent by the switching controller; adjustable by compensating element parameter regulatorThe switch is controlled by the inductor, the capacitor or the compensating element to switch the values of the transmitting end compensating inductor and the capacitor and to switch the compensating inductor L of the corresponding value gear_{0 change}And a compensation capacitor C_{0 change}、C_{1 change}Connected to the power transfer module.

According to the technical scheme, the beneficial effects of the invention are as follows: firstly, compared with the traditional wireless charging system, the wireless charging system is based on the standard LCC compensation topology and the improved LCC compensation topology, and the adjustable inductor, the capacitor or the compensation element control switch is used for carrying out numerical value switching on the corresponding compensation inductor or capacitor, so that the adjustment of the output voltage gain of the system is realized, and the stability of the output voltage of the system is improved; secondly, in a wireless charging system with standard LCC-S compensation or improved LCC-S compensation, the compensation inductance L of a transmitting end is controlled_{0 change}And a compensation capacitor C_{0 change}、C_{1 change}Or a transmitting end compensation capacitor C_t、C_{0 change}、C_{1 change}The synchronous conversion of the numerical values ensures that the wireless charging system always works in a resonance state, and is beneficial to improving the efficiency of energy transmission; thirdly, the numerical value gear switching of the compensation element of the transmitting end is controlled by detecting the input current of the transmitting end, so that the communication between the transmitting end and the receiving end is avoided, and a control system is simplified; fourthly, the adjustment proportion of the numerical value gear of the transmitting end compensation element is more uniform in order to deal with the mutual inductance change of the coupling coil, and the stepless adjustment of the output voltage gain can be realized theoretically by using the adjustable inductor and the capacitor.

Drawings

Fig. 1 is a schematic structural diagram of a wireless charging system;

FIG. 2 is a standard LCC compensation topology of the present invention employing adjustable inductors and capacitors;

FIG. 3 is a standard LCC compensation topology of the present invention employing compensation element control switches;

FIG. 4 is an improved LCC compensation topology of the present invention employing an adjustable capacitor;

FIG. 5 is an improved LCC compensation topology of the present invention employing compensation element control switches;

FIG. 6 is an equivalent circuit diagram of a standard LCC-S compensation topology of the present invention employing adjustable inductors and capacitors;

FIG. 7 is an equivalent circuit diagram of a standard LCC-S compensation topology of the present invention employing a compensation element to control the switch;

FIG. 8 is an equivalent circuit diagram of the improved LCC-S compensation topology of the present invention employing an adjustable capacitor;

FIG. 9 is an equivalent circuit diagram of an improved LCC-S compensation topology of the present invention employing a compensation element to control the switch;

FIG. 10 is a block diagram of output voltage regulation control for a wireless charging system employing a modified LCC-S compensation topology;

FIG. 11 is a block diagram of output voltage regulation control for a wireless charging system employing a standard LCC-S compensation topology;

FIG. 12, FIG. 13, and FIG. 14 are respectively a compensation capacitor C of the transmitting terminal_tAnd S_ACombination, C₀And S_BCombination, C₁And S_CCombined capacitive matrix diagrams.

Detailed Description

As shown in fig. 1, a wireless charging system includes:

the information detection module 1 is used for detecting the relative positions of a receiving end coil and a transmitting end coil in the electric energy transmission module, detecting the input current of a transmitting end, and transmitting offset signals of the receiving end coil and the transmitting end coil and input current signals in the transmitting end coil to a switching controller of a transmitting end compensation element switching control system 4;

the electric energy transmission module is used for wirelessly transmitting the electric energy supplied by the power grid to a receiving end of the wireless charging system to charge the battery;

the transmitting end compensation element switching control system 4 is used for judging the working modes of the switching controller according to the detected position information of the receiving end coil, wherein the working modes comprise a power supply starting mode and a power supply stopping mode; in the process of starting and operating the switching controller, according to a detected signal of current input at the transmitting end, judging the switching mode of a numerical gear of the compensating element at the transmitting end, wherein the switching mode comprises gear-up operation and gear-down operation, sending a corresponding gear switching instruction to the compensating element parameter regulator, and according to the instruction signal, the parameter regulator controls the switch by controlling the adjustable inductor, the capacitor or the compensating element to switch the numerical value of the compensating inductor or the capacitor at the transmitting end and accesses the corresponding compensating inductor or the capacitor to the electric energy transmission module.

The information detection module 1 includes:

the coil position detection device consists of two position sensors which are arranged at the front side and the rear side of the transmitting end coil and are used for detecting the motion state information of the electric energy pickup coil and transmitting the offset between the electric energy pickup coil at the receiving end and the center of the transmitting end power supply guide rail coil to the switching controller;

and the current sensor is used for detecting the input current of the coil at the transmitting end of the system and transmitting the current signal to the switching controller.

The power transmission module includes:

the transmitting end electric energy conversion circuit 2 consists of a rectifying circuit, a Boost type Power Factor Correction (PFC) circuit, a Buck voltage regulating circuit and a high-frequency inverter circuit; the alternating current transformer is used for converting alternating current from a power grid into alternating current with controllable voltage and frequency and injecting the alternating current into a transmitting end coil;

the receiving end electric energy conversion circuit 3 consists of a rectifying filter circuit and a DC-DC circuit and is used for converting alternating current induced in a receiving end coil into direct current and providing stable charging voltage for a battery load through the control of the DC-DC circuit;

the receiving and transmitting end coil system comprises a receiving end coil and a transmitting end coil, and realizes wireless transmission of energy in an air gap through electromagnetic coupling of the transmitting end coil and the receiving end coil;

the receiving and transmitting end compensation network module is used for improving wireless charging efficiency, system active power and power factors and comprises a transmitting end compensation network and a receiving end compensation network, wherein the transmitting end compensation network adopts a standard LCC compensation topology or an improved LCC compensation topology, and the receiving end compensation network adopts a series compensation topology;

the standard LCC compensation topology is divided into two types, one is a standard LCC compensation topology using adjustable inductance and capacitance, as shown in figure 2,wherein the adjustable inductor is L'_{0 tone}The capacitor is C'_{0 tone}、C’_{1 tone}(ii) a The other is a standard LCC compensation topology with compensation element control switches, as shown in FIG. 3, where the compensation element control switch is S'_A、S’_BAnd S'_CCorresponding compensation inductance L₀And a compensation capacitor C₀And C₁Then the form of matrix inductance and matrix capacitance is adopted; the improved LCC compensation topology is divided into two types, one is an improved LCC compensation topology using an adjustable capacitor, as shown in fig. 4, where the adjustable capacitor is C_{tone of t}、C_{0 tone}、C_{1 tone}(ii) a Another is an improved LCC compensation topology using a compensation element controlled switch, as shown in FIG. 5, wherein the compensation element controlled switch includes S_A、S_BAnd S_CCorresponding compensation capacitor C_t、C₀And C₁Then a matrix capacitance form is adopted; when the transmitting terminal compensation network adopts a standard LCC compensation topology, the standard LCC compensation topology and the series compensation topology form a standard LCC-S compensation topology together; when the transmitting terminal compensation network adopts the improved LCC compensation topology, the improved LCC compensation topology and the series compensation topology jointly form an improved LCC-S compensation topology;

the transmitting-end compensation element switching control system 4 includes:

the switching controller is used for switching the compensation element connected into the main circuit of the transmitting terminal according to the change of the input current of the transmitting terminal so as to achieve the aim of adjusting the compensation inductance or capacitance value;

and the compensation element parameter adjuster is used for executing the instruction of the switching controller, controlling the adjustable inductor, the capacitor or the compensation element control switch, carrying out numerical value switching on the corresponding transmission end compensation inductor or capacitor, and connecting the corresponding compensation inductor or capacitor with the transmission end electric energy conversion circuit 2 and the transmission end coil to finish electric energy transmission of the transmission end.

As shown in FIG. 7, the standard LCC-S compensation topology of the standard LCC compensation topology using compensation element control switches includes a compensation inductor L₀A first compensation capacitor C of the transmitting terminal₀A second compensation capacitor C of the transmitting terminal₁And a receiving end compensation capacitor C₂(ii) a Wherein the compensation inductance L₀In the form of a matrix inductor and controlling switch S'_AConnected to each other through a switching control switch S'_ARealize the compensation inductance L₀The two values together form a compensation inductance which can be switched and is marked as L_{0 switch}(ii) a First compensation capacitor C of transmitting terminal₀In the form of a matrix capacitor and controlling switch S'_BConnected to each other through a switching control switch S'_BRealize the first compensation capacitor C₀The two together form a compensation capacitor, denoted as C, which can be switched on and off_{0 switch}(ii) a Second compensation capacitor C of transmitting terminal₁In the form of a matrix capacitor and controlling switch S'_CConnected to each other through a switching control switch S'_CTo C₁The two together form a compensation capacitor, denoted as C, which can be switched on and off_{1 switch}(ii) a Compensating inductance L capable of switching₀Is connected with an input voltage U_inPositive pole of (2), compensation inductance L capable of switching_{0 switch}The other end of the capacitor is respectively connected with a compensating capacitor C capable of switching_{0 switch}The compensating capacitor C can be switched on and off_{1 switch}Are connected at one end, and C_{1 switch}Another end of and a transmitting end coil L₁Are connected in series at one end, and C_{0 switch}Another end, transmitting end coil L₁The other ends of the two ends are connected with an input voltage U_inNegative pole, transmitting end coil L₁And a receiving end coil L₂Are electromagnetically coupled, the mutual inductance of the coupling coil is M, and the receiving end coil L₂Receiving end compensation capacitor C₂Equivalent load R_LForm a series loop with a system input current of I_inThe current in the coil at the transmitting end is I₁The current in the series loop in which the receiving end coil is located is I₂The voltage across the equivalent load is U_out；

As shown in FIG. 6, the standard LCC-S compensation topology adopting the standard LCC compensation topology with adjustable inductance and capacitance comprises a transmitting end compensation inductance L'_{0 tone}And a first compensation capacitor C 'at a transmitting end'_{0 tone}And a second compensation capacitor C 'of a transmitting end'_{1 tone}And a receiving end compensation capacitor C₂(ii) a Power supply U_inThe positive electrode and the transmitting end of the transformer compensate inductance L'_{0 tone}Is connected with a transmitting end to compensate inductance L'_{0 tone}The other end of the first capacitor is respectively connected with a first compensation capacitor C 'of the transmitting end'_{0 tone}And a second compensation capacitor C 'of a transmitting end'_{1 tone}Is connected with a transmitting end and is provided with a second compensation capacitor C'_{1 tone}Another end of and a transmitting end coil L₁Is connected in series with a first compensation capacitor C 'at the transmitting end'_{0 tone}Another end, transmitting end coil L₁The other ends of the two ends are connected with an input voltage U_inNegative pole, transmitting end coil L₁And a receiving end coil L₂Are electromagnetically coupled, the mutual inductance of the coupling coil is M, and the receiving end coil L₂Receiving end compensation capacitor C₂Equivalent load R_LForm a series loop with a system input current of I_inThe current in the coil at the transmitting end is I₁The current in the series loop in which the receiving end coil is located is I₂The voltage across the equivalent load is U_out。

As shown in fig. 9, the improved LCC-S compensation topology of the improved LCC compensation topology using compensation element control switch includes a transmission-side compensation inductor L₀A first compensation capacitor C of the transmitting terminal_tA second compensation capacitor C of the transmitting terminal₀A third compensation capacitor C of the transmitting terminal₁And a receiving end compensation capacitor C₂(ii) a Wherein, the first compensation capacitor C of the transmitting terminal_tIn the form of a matrix inductor and associated control switch S_AConnected by a changeover control switch S_ARealize the first compensation capacitor C_tThe two together form a compensation capacitor, denoted as C, which can be switched on and off_t-switch(ii) a Second compensation capacitor C of transmitting terminal₀In the form of a matrix capacitor and associated control switch S_BConnected by a changeover control switch S_BTo C₀The values of (A) and (B) are switched, and the values form a compensation capacitor which can be switched on and off, C_{0 switch}(ii) a Transmit side third compensationCapacitor C₁In the form of a matrix capacitor and associated control switch S_CConnected by a changeover control switch S_CTo C₁The values of (A) and (B) are switched, and the values form a compensation capacitor which can be switched on and off, C_{1 switch}(ii) a Transmitting terminal compensation inductance L₀Is connected with an input voltage U_inThe positive electrode of (2), the transmitting terminal compensation inductance L₀And the other end of the capacitor C and a compensation capacitor C capable of switching_t-switchAre connected to one end of C_t-switchThe other end of the capacitor is respectively connected with a compensating capacitor C capable of switching_{0 switch}The compensating capacitor C can be switched on and off_{1 switch}Are connected at one end, and C_{1 switch}Another end of and a transmitting end coil L₁Are connected in series at one end, and C_{0 switch}Another end, transmitting end coil L₁The other ends of the two ends are connected with an input voltage U_inNegative pole, transmitting end coil L₁And a receiving end coil L₂Are electromagnetically coupled, the mutual inductance of the coupling coil is M, and the receiving end coil L₂Receiving end compensation capacitor C₂Equivalent load R_LForming a series loop with a current I in the coil at the transmitting end₁The current in the series loop in which the receiving end coil is located is I₂The voltage across the equivalent load is U_out；

As shown in fig. 8, the improved LCC-S compensation topology using the improved LCC compensation topology with adjustable capacitance includes a transmitting end compensation inductor L₀A first compensation capacitor C of the transmitting terminal_{tone of t}A second compensation capacitor C of the transmitting terminal_{0 tone}A third compensation capacitor C of the transmitting terminal_{1 tone}And a receiving end compensation capacitor C₂(ii) a Transmitting terminal compensation inductance L₀Is connected with an input voltage U_inThe positive electrode of (2), the transmitting terminal compensation inductance L₀Another end of the first compensation inductor C and the transmitting end_{tone of t}Is connected with one end of the first compensation inductor C at the transmitting end_{tone of t}The other end of the first compensation capacitor is respectively connected with the transmitting end and the second compensation capacitor C_{0 tone}A third compensation capacitor C of the transmitting terminal_{1 tone}Is connected with one end of the first compensating capacitor C_{1 tone}Another end of and a transmitting end coil L₁One end of the first and second transistors is connected in series, and the transmitting end is the firstTwo compensation capacitors C₀Another end, transmitting end coil L₁The other ends of the two ends are connected with an input voltage U_inNegative pole, transmitting end coil L₁And a receiving end coil L₂Are electromagnetically coupled, the mutual inductance of the coupling coil is M, and the receiving end coil L₂Receiving end compensation capacitor C₂Equivalent load R_LForming a series loop with a current I in the coil at the transmitting end₁The current in the series loop in which the receiving end coil is located is I₂The voltage across the equivalent load is U_out。

The method comprises the following steps in sequence:

(1) establishing a circuit model of the wireless charging system based on the standard LCC-S compensation topology and the improved LCC-S compensation topology respectively, analyzing the relation between the voltage gain of the wireless charging system of the standard LCC-S compensation topology and the parameter value of a compensation element, and analyzing the relation between the parameter of the compensation element and the inductance of a coil when the system works in a resonance state; analyzing the relationship between the voltage gain of the wireless charging system of the improved LCC-S compensation topology and the parameter value of the compensation element, and analyzing the relationship between the parameter of the compensation element and the coil inductance when the system works in a resonance state; the standard LCC-S compensation topology means that a transmitting end compensation network adopts a standard LCC compensation topology, and a receiving end compensation network adopts a series compensation topology; the improved LCC-S compensation topology means that the transmitting end compensation network adopts the improved LCC compensation topology, and the receiving end compensation network adopts the series compensation topology;

(2) according to different compensation topologies adopted by a system transmitting end, respectively designing a numerical value gear of a transmitting end compensation element parameter of the wireless charging system with a standard LCC-S compensation topology and a numerical value gear of a transmitting end compensation element parameter of the wireless charging system with an improved LCC-S compensation topology according to the relation between corresponding voltage gain and the compensation element parameter value;

(3) designing a corresponding switching controller according to a compensation topology adopted by a system transmitting end: firstly, transmitting a collected central position signal of a receiving and transmitting end coil to a switching controller so as to start/stop supplying power to a transmitting end coil; secondly, inputting the collected input current signal of the transmitting end into a switching controller, and calculating the current output voltage gain according to the input voltage value of the transmitting end, the coil inductance and the load resistance value; then, transmitting the obtained voltage gain signal to a switching controller, comparing a standard voltage gain value with an actual voltage gain signal fed back in real time, determining a target value gear of the compensation element, and sending a compensation element target value gear signal to a compensation element parameter regulator; and finally, the compensation element parameter regulator sends out an instruction for switching the compensation element parameters, and controls the adjustable inductor, the capacitor or the compensation element control switch to switch the corresponding compensation inductor or capacitance value, so as to realize the control of the compensation element parameter regulation of the wireless charging system.

Example one

Analyzing the relationship between the voltage gain of the wireless charging system with the improved LCC-S compensation topology and the parameter value of the compensation element in the step (1), and analyzing the relationship between the parameter of the compensation element and the inductance of the coil when the system works in a resonance state specifically means that:

output voltage gain H_uThe relation between the parameters of the compensation element and the inductance of the coil is as follows:

where ω is the system operating frequency, L₀Compensation of inductance for the transmitting end, C_tIs equal to L₀A compensation capacitor connected in series; λ 1/(ω)²L₀C_t) To compensate for capacitance C_tAdjusting the coefficient; in the improved LCC-S compensation topology, if the system input voltage and the series compensation inductance L₀If the relationship is kept unchanged, the relationship is simplified as follows:

H_uL₀/M₀＝μ·p (2)

wherein, mu-1/(1-lambda) is compensation coefficient of mutual inductance variation of the coupling coil, and p-M/M₀For mutual inductance variation coefficient, M and M₀The mutual inductance of the coupling coils at the current position and the position opposite to the coil at the receiving and transmitting end is respectively;

the step (2) of designing the numerical value gear of the parameter of the transmitting end compensation element of the wireless charging system with the improved LCC-S compensation topology specifically comprises the following steps:

when the mutual inductance fluctuation of the coupling coil is caused by the coil offset of the transmitting and receiving ends, the mutual inductance value at the current position is assumed as follows: m_i＝p_iM₀，p_iThe coefficient of variation of mutual inductance is more than or equal to 20 percent and less than or equal to p_iThe output voltage gain of the system is adjusted by changing the compensation capacitance value of the transmitting end to be less than or equal to 100 percent; let the capacitance C of the current gear_ti＝q_iC₀At the initial resonant frequency, C_tThe variation of the value is expressed as a capacitance adjustment coefficient lambda_iAnd mutual inductance variation compensation coefficient mu_iThe change of (2):

wherein i is the gear at which the compensation element is currently located, and each numerical gear of the compensation element corresponds to a mutual inductance value change interval; q is a capacitor C_tA scaling factor of (c); meanwhile, in order to satisfy the resonance condition, the capacitor C needs to be synchronously adjusted_{0 change}And C_{1 change}Comprises the following steps:

thus, reference is made to the capacitance C₁And a capacitor C_tiAre connected in series to obtain a capacitor C_{1 change}(ii) a Through the mutual inductance variation coefficient p of the coupling coil_iAnd mutual inductance variation compensation coefficient mu_iDetermining the required value gear i of the compensating element so as to obtain the compensating capacitor C_t、C_{0 change}And C_{1 change}The numerical values of the gears; wherein, C_{0 change}、C_{1 change}Compensating capacitors C for the transmitting terminals, respectively₀、C₁The value after gear adjustment;

setting a transmitting end compensation capacitor C according to the adjustment gear corresponding to the current mutual inductance value of the coupling coil_t、C_{0 change}And C_{1 change}The numerical gear of (2) as shown in table 1:

TABLE 1 variable values of each gear of the compensation capacitor

Determining a compensation capacitor C according to the capacitance values in Table 1_tAs shown in FIG. 12, wherein the capacitor C_b＝2*C₀，C_c＝3*C₀，C_d＝5*C₀，C_e＝C₀/2，C_f＝C₀And/3, each capacitance value is expressed as an initial value C of the parallel compensation capacitor of the transmitting terminal₀Multiples of (a). In addition, a compensation element control switch S is provided_A、S_B、S_CThe numerical gear of the compensation capacitor at the transmitting end is controlled and adjusted, wherein: control switch S_AComprising a switch S_A0～S_A10For adjusting the value of the capacitor Ct, control switch S_BComprising a switch S_B0～S_B9For regulating the capacitance C_{0 change}The numerical value gear of (1), the control switch S_CComprising a switch S_C0～S_C10For regulating the capacitance C_{1 change}The numerical gear of (1). Compensation capacitor C_tTotally provided with nine numerical gears which are respectively provided with a switch S_A0～S_A10And (5) controlling. When adding the compensation capacitor C_tWhen the value of (C) is changed, the capacitance C can be determined according to equation (4) in order to ensure that the transmitting end system operates in a resonant state_{0 change}And a capacitor C_{1 change}As shown in table 1, and determines the corresponding switching scheme. FIG. 13 shows a compensation capacitor C at the transmitting end_{0 change}The compensation capacitor C shown in FIG. 14_{1 change}From a reference capacitor C₁And a compensation capacitor C_tAre connected in series to obtain. According to the combination scheme of the compensation capacitors, the switch closing condition of each gear of the capacitors is determined, and the result is shown in table 2.

TABLE 2 switch for controlling the closing of each gear of compensation capacitor

In step (3), designing the transmission-side compensation element switching controller according to the improved LCC-S compensation topology specifically includes the following steps:

3a1) starting control:

in the process that the receiving end coil gradually approaches to the transmitting end coil, when the position sensor arranged on the front end side of the transmitting end coil detects that the receiving end coil arrives, the position sensor sends a starting signal and transmits the starting signal to the switching controller to control the initial compensation network to be connected into the main circuit, and the corresponding transmitting end coil is in a power supply state; when the position sensor arranged on the rear end side of the transmitting end coil detects that the receiving end coil is completely separated, the coil position sensor sends out a termination signal and transmits the termination signal to the switching controller, at the moment, the compensation network is cut off, and the corresponding transmitting end coil is in an idle state;

3b1) system input current detection and feedback control:

in the improved LCC-S compensation topology, the relationship between the system input current and the voltage gain is:

wherein, ξ_i＝H_u/H_u0＝μ_ip_iFor the system output voltage gain factor, H_u0Is a reference value of voltage gain, and in the current detection and switching control procedure, the voltage gain coefficient when the receiving and transmitting end coil is over against is used as the reference value ξ₀Order ξ_i＝ξ ₀1 is ═ 1; therefore, when the system input voltage is kept constant, the transmitting terminal input current value can be detected through the current sensor, and the magnitude relation between the gain coefficient of the system output voltage and the standard value 1 is compared to determine the upshifting or downshifting of the compensation element parameter value gear.

In practical operation, when the system obtains a stable output voltage gain at time t, the system output voltage gain factor is ξ₀. The input current value can be detected as I at time t and at time t + Δ t, respectively_in(t) and I_in(t + Δ t), transmitting the measured value to a switching controller, and comparing the two measurements before and afterAnd determining the change condition of the mutual inductance value according to the input current value of the quantity, and switching the gear of the compensation capacitance value of the transmitting terminal. If I_in(t)>I_in(t + Δ t), the system input current gradually decreases and the system output voltage gain factor ξ_i<1, at this time, the output voltage of the system is lower than the standard value, and the value of the compensation capacitance of the transmitting terminal needs to be gradually increased until the voltage gain coefficient ξ_iClose to 1. The specific flow of the control scheme is shown in fig. 10.

3c1) The parameter switching of the compensation element controlled in the step (3) is specifically as follows: determining the upshifting/downshifting operation of the value of the compensating element according to the compensating element target value gear signal sent by the switching controller; the adjustable capacitor or the compensation element control switch is controlled by the compensation element parameter regulator to switch the value of the compensation capacitor at the transmitting end, and the compensation capacitor C of the corresponding value gear is switched_t、C_{0 change}、C_{1 change}Connected to the power transfer module.

Example two

Analyzing the relationship between the voltage gain of the wireless charging system with the standard LCC-S compensation topology and the parameter value of the compensation element in the step (1), and analyzing the relationship between the parameter of the compensation element and the coil inductance when the system works in the resonance state specifically means:

output voltage gain H_uThe relation between the parameters of the compensation element and the inductance of the coil is as follows:

wherein M is the mutual inductance of the coupling coil at the current position, L₀The inductance is compensated for the transmitting end.

The step (2) of designing the numerical value gear of the parameter of the transmitting end compensation element of the wireless charging system with the standard LCC-S compensation topology specifically comprises the following steps:

when the mutual inductance fluctuation of the coupling coil is caused by the coil offset of the transmitting and receiving ends, the mutual inductance value at the current position is assumed as follows: m_i＝p_iM₀，p_iP is a mutual inductance variation coefficient of more than or equal to 20%_iAnd (3) the gain of the output voltage of the system is less than or equal to 100 percent: h_u＝p_iM₀/L_{0 change}(ii) a Wherein L is_{0 change}Compensating the capacitance L for the transmitting end₀The value after gear adjustment; at this time, L can be adjusted by changing the compensation inductance value of the transmitting terminal_{0 to i}＝a_iL₀Thereby adjusting the output voltage gain of the system:

wherein i is a compensation capacitor C_{0 change}Each numerical gear of the compensation element corresponds to a mutual inductance value change interval; a is compensation inductance L_{0 change}The adjustment coefficient of (2) represents the mutual inductance value of the coupling coil of the current gear and the mutual inductance value L of the initial moment₀The ratio of (A) to (B); thus to maintain the output voltage gain H_uAnd (4) stability is realized only by ensuring that the p/a is unchanged. Setting a compensation inductance L of a transmitting end according to an adjusting gear corresponding to a current mutual inductance value of the coupling coil_{0 change}And a capacitor C_{0 change}、C_{1 change}The numerical gear of (2) is shown in table 3.

TABLE 3 inductor-capacitor combination scheme for each gear value and parameter

Meanwhile, in order to make the system work in a resonance state, the compensation capacitor C needs to be synchronously adjusted_{0 change}、C_{1 change}：

Thus, the initial capacitance C₁And a capacitor C_String＝C₀/(1-p) are connected in series to obtain a capacitor C_{1 change}(ii) a Through the mutual inductance variation coefficient p of the coupling coil_iAnd a voltage gain, determining the required value gear i of the compensation element, thereby obtaining the compensation inductance L_{0 change}And a capacitor C_{0 change}、C_{1 change}Number of each gearThe value is obtained.

In step (3), designing the transmitting terminal compensation element switching controller according to the standard LCC-S compensation topology specifically includes the following steps:

3a2) starting control:

in the process that the receiving end coil gradually approaches to the transmitting end guide rail coil, when the position sensor arranged on the front end side of the transmitting end coil detects that the receiving end coil arrives, the position sensor sends out a starting signal and transmits the starting signal to the switching controller to control the initial compensation network to be connected into the main circuit, and the corresponding transmitting end coil is in a power supply state; when the position sensor arranged on the rear end side of the transmitting end coil detects that the receiving end coil is completely separated, the coil position sensor sends out a termination signal and transmits the termination signal to the switching controller, at the moment, the compensation network is cut off, and the corresponding transmitting end coil is in an idle state;

3b2) system input current detection and feedback control link

In the LCC-S compensation topology, the relationship between the system input current and the voltage gain is as follows:

wherein, κ_i＝H_u/H_u0＝p_i/a_iFor the system output voltage gain factor, H_u0A reference value that is a voltage gain; in the current detection and switching control link, the voltage gain coefficient when the transmitting and receiving end coil is aligned is used as the reference value k₀Let κ be_i＝κ ₀1 is ═ 1; therefore, when the system input voltage is kept constant, the transmitting terminal input current value can be detected through the current sensor, and the magnitude relation between the gain coefficient of the system output voltage and the standard value 1 is compared to determine the upshifting or downshifting of the compensation element parameter value gear.

In practical operation, when the system obtains a stable output voltage gain at time t, the system output voltage gain factor is k₀. The input current value can be detected as I at time t and at time t + Δ t, respectively_in(t) and I_in(t + Δ t), will measureThe value is transmitted to a switching controller, the change condition of the mutual inductance value is determined by comparing the input current values measured before and after twice, and the gear of the compensation capacitance value of the transmitting end is switched. If I_in(t)>I_in(t + Δ t), the system input current gradually decreases, and the system output voltage gain factor κ_i<1, when the output voltage of the system is lower than the standard value, the compensation capacitance C of the transmitting terminal needs to be gradually increased_tUp to the voltage gain factor k_iClose to 1. The specific flow of this control scheme is shown in fig. 11.

3c2) The compensating element controlled in the step (3)

The switching of the switch is specifically as follows: determining the upshifting/downshifting operation of the value of the compensating element according to the compensating element target value gear signal sent by the switching controller; the adjustable inductance, the capacitance or the compensation element control switch is controlled by the compensation element parameter adjuster to switch the values of the compensation inductance and the capacitance of the transmitting end, and the compensation inductance L of the corresponding value gear is switched_{0 change}And a compensation capacitor C_{0 change}、C_{1 change}Connected to the power transfer module.

In summary, the invention uses the control switch to switch the corresponding compensation inductor or capacitor based on the standard LCC compensation topology and the improved LCC compensation topology, so as to adjust the gain of the system output voltage and improve the stability of the system output voltage; control transmitting terminal compensation capacitor C_t、C_{0 change}、C_{1 change}The synchronous conversion of the numerical values ensures that the wireless charging system always works in a resonance state, and is beneficial to improving the efficiency of energy transmission; the input current of the transmitting terminal is detected to control the numerical value gear switching of the compensating element of the transmitting terminal, so that the communication between the transmitting and receiving terminals is avoided, and a control system is simplified; the adjustment proportion of the numerical value gear of the transmitting end compensation element, which is set for coping with the mutual inductance change of the coupling coil, is more uniform, and the stepless adjustment of the output voltage gain can be realized theoretically.

Claims (9)

1. A wireless charging system, characterized in that: the method comprises the following steps:

the information detection module is used for detecting the relative positions of a receiving end coil and a transmitting end coil in the electric energy transmission module, detecting the input current of a transmitting end, and transmitting offset signals of the receiving end coil and the transmitting end coil and input current signals in the transmitting end coil to a switching controller of a transmitting end compensation element switching control system;

the electric energy transmission module is used for wirelessly transmitting the electric energy supplied by the power grid to a receiving end of the wireless charging system to charge the battery;

the transmitting end compensation element switching control system is used for judging the working mode of the switching controller according to the detected position information of the receiving end coil, and the working mode comprises a power supply starting mode and a power supply stopping mode; in the process of starting and operating the switching controller, according to a detected signal of current input at the transmitting end, judging the switching mode of a numerical gear of the compensating element at the transmitting end, wherein the switching mode comprises gear-up operation and gear-down operation, sending a corresponding gear switching instruction to the compensating element parameter regulator, and according to the instruction signal, the parameter regulator controls the switch by controlling the adjustable inductor, the capacitor or the compensating element to switch the numerical value of the compensating inductor or the capacitor at the transmitting end and accesses the corresponding compensating inductor or the capacitor to the electric energy transmission module.

2. The wireless charging system of claim 1, wherein: the information detection module includes:

the coil position detection device consists of two position sensors which are arranged at the front side and the rear side of the transmitting end coil and are used for detecting the motion state information of the electric energy pickup coil and transmitting the offset between the electric energy pickup coil at the receiving end and the center of the transmitting end power supply guide rail coil to the switching controller;

and the current sensor is used for detecting the input current of the coil at the transmitting end of the system and transmitting the current signal to the switching controller.

3. The wireless charging system of claim 1, wherein: the power transmission module includes:

the transmitting end electric energy conversion circuit consists of a rectifying circuit, a Boost type Power Factor Correction (PFC) circuit, a Buck voltage regulating circuit and a high-frequency inverter circuit; the alternating current transformer is used for converting alternating current from a power grid into alternating current with controllable voltage and frequency and injecting the alternating current into a transmitting end coil;

the receiving end electric energy conversion circuit consists of a rectifying filter circuit and a DC-DC circuit and is used for converting alternating current induced in a receiving end coil into direct current and providing stable charging voltage for a battery load through the control of the DC-DC circuit;

the receiving and transmitting end coil system comprises a receiving end coil and a transmitting end coil, and realizes wireless transmission of energy in an air gap through electromagnetic coupling of the transmitting end coil and the receiving end coil;

the receiving and transmitting end compensation network module is used for improving wireless charging efficiency, system active power and power factors and comprises a transmitting end compensation network and a receiving end compensation network, wherein the transmitting end compensation network adopts a standard LCC compensation topology or an improved LCC compensation topology, and the receiving end compensation network adopts a series compensation topology; the standard LCC compensation topology is divided into two types, one type is the standard LCC compensation topology adopting adjustable inductance and capacitance, wherein the adjustable inductance is

The capacitor is

The other is a standard LCC compensation topology employing a compensation element control switch, wherein the compensation element control switch is S'_A、S’_BAnd S'_C(ii) a The improved LCC compensation topology is divided into two types, one type is the improved LCC compensation topology adopting an adjustable capacitor, wherein the adjustable capacitor is

Another is an improved LCC compensation topology employing a compensation element controlled switch, wherein the compensation element controlled switch includes S_A、S_BAnd S_C(ii) a When transmitting end compensation networkA standard LCC compensation topology is adopted, and the standard LCC compensation topology and the series compensation topology form a standard LCC-S compensation topology; when the transmitting terminal compensation network adopts the improved LCC compensation topology, the improved LCC compensation topology and the series compensation topology jointly form an improved LCC-S compensation topology;

the transmitting end compensation element switching control system comprises:

the switching controller is used for switching the compensation element connected into the main circuit of the transmitting terminal according to the change of the input current of the transmitting terminal so as to achieve the aim of adjusting the compensation inductance or capacitance value;

and the compensation element parameter regulator is used for executing the instruction of the switching controller, controlling the adjustable inductor, the capacitor or the compensation element control switch, carrying out numerical value switching on the corresponding transmitting end compensation inductor or capacitor, and connecting the corresponding compensation inductor or capacitor with the transmitting end electric energy conversion circuit and the transmitting end coil to finish electric energy transmission of the transmitting end.

4. The wireless charging system of claim 3, wherein: the standard LCC-S compensation topology of the standard LCC compensation topology adopting the compensation element to control the switch comprises a compensation inductor L₀A first compensation capacitor C of the transmitting terminal₀A second compensation capacitor C of the transmitting terminal₁And a receiving end compensation capacitor C₂(ii) a Wherein the compensation inductance L₀In the form of a matrix inductor and controlling switch S'_AConnected to each other through a switching control switch S'_ARealize the compensation inductance L₀The two values together form a compensation inductance which can be switched, and is recorded as

First compensation capacitor C of transmitting terminal₀In the form of a matrix capacitor and controlling switch S'_BConnected to each other through a switching control switch S'_BRealize the first compensation capacitor C₀The two values together form a compensation capacitor which can be switched, and is recorded as

Second compensation capacitor C of transmitting terminal₁In the form of a matrix capacitor and controlling switch S'_CConnected to each other through a switching control switch S'_CTo C₁The two values together form a compensation capacitor which can be switched, and is recorded as

Compensating inductance L capable of switching₀Is connected with an input voltage U_inPositive pole of (2), compensation inductance capable of switching

The other end of the capacitor is respectively connected with a compensation capacitor capable of switching

Compensating capacitor capable of switching

Are connected at one end to

Another end of and a transmitting end coil L₁Is connected in series at one end, and

another end, transmitting end coil L₁The other ends of the two ends are connected with an input voltage U_inNegative pole, transmitting end coil L₁And a receiving end coil L₂Are electromagnetically coupled, the mutual inductance of the coupling coil is M, and the receiving end coil L₂Receiving end compensation capacitor C₂Equivalent load R_LForm a series loop with a system input current of I_inThe current in the coil at the transmitting end is I₁The current in the series loop in which the receiving end coil is located is I₂The voltage across the equivalent load is U_out；

The standard LCC-S compensation topology adopting the standard LCC compensation topology with the adjustable inductor and the adjustable capacitor comprises a transmitting end compensation inductor

First compensation capacitor of transmitting terminal

Second compensation capacitor of transmitting terminal

And a receiving end compensation capacitor C₂(ii) a Power supply U_inThe positive pole and the transmitting terminal of the inductor are compensated

Is connected with one end of the transmitting end, and the transmitting end compensates the inductance

The other end of the first compensating capacitor is respectively connected with the transmitting end

Second compensation capacitor of transmitting terminal

One end of the first compensating capacitor is connected with the other end of the second compensating capacitor

Another end of and a transmitting end coil L₁One end of the first compensating capacitor is connected in series, and the transmitting end of the first compensating capacitor is connected in series

Another end, transmitting end coil L₁The other ends of the two ends are connected with an input voltage U_inNegative pole, transmitting end coil L₁And a receiving end coil L₂Are electromagnetically coupled, the mutual inductance of the coupling coils is M,receiving end coil L₂Receiving end compensation capacitor C₂Equivalent load R_LForm a series loop with a system input current of I_inThe current in the coil at the transmitting end is I₁The current in the series loop in which the receiving end coil is located is I₂The voltage across the equivalent load is U_out。

5. The wireless charging system of claim 3, wherein: the improved LCC-S compensation topology of the improved LCC compensation topology using compensation element control switch comprises a transmitting end compensation inductance L₀A first compensation capacitor C of the transmitting terminal_tA second compensation capacitor C of the transmitting terminal₀A third compensation capacitor C of the transmitting terminal₁And a receiving end compensation capacitor C₂(ii) a Wherein, the first compensation capacitor C of the transmitting terminal_tIn the form of a matrix inductor and associated control switch S_AConnected by a changeover control switch S_ARealize the first compensation capacitor C_tThe two values together form a compensation capacitor which can be switched, and is recorded as

Second compensation capacitor C of transmitting terminal₀In the form of a matrix capacitor and associated control switch S_BConnected by a changeover control switch S_BTo C₀The two together form a compensation capacitor capable of switching,

third compensation capacitor C of transmitting terminal₁In the form of a matrix capacitor and associated control switch S_CConnected by a changeover control switch S_CTo C₁The two together form a compensation capacitor capable of switching,

transmitting terminal compensation inductance L₀Is connected with an input voltage U_inThe positive electrode of (2), the transmitting terminal compensation inductance L₀And the other end of the capacitor and a compensation capacitor capable of switching

One end of the two ends of the connecting rod is connected,

the other end of the capacitor is respectively connected with a compensation capacitor capable of switching

Compensating capacitor capable of switching

Are connected at one end to

Another end of and a transmitting end coil L₁Is connected in series at one end, and

another end, transmitting end coil L₁The other ends of the two ends are connected with an input voltage U_inNegative pole, transmitting end coil L₁And a receiving end coil L₂Are electromagnetically coupled, the mutual inductance of the coupling coil is M, and the receiving end coil L₂Receiving end compensation capacitor C₂Equivalent load R_LForming a series loop with a current I in the coil at the transmitting end₁The current in the series loop in which the receiving end coil is located is I₂The voltage across the equivalent load is U_out；

The improved LCC-S compensation topology of the improved LCC compensation network with adjustable capacitance comprises a transmitting end compensation inductance L₀A first compensation capacitor at the transmitting end

Second compensation capacitor of transmitting terminal

Third compensation capacitor of transmitting terminal

And a receiving end compensation capacitor C₂(ii) a Transmitting terminal compensation inductance L₀Is connected with an input voltage U_inThe positive electrode of (2), the transmitting terminal compensation inductance L₀Another end of the first compensation inductor and the transmitting end of the second compensation inductor

Is connected with one end of the first compensating inductor at the transmitting end

The other end of the first compensation capacitor is respectively connected with the transmitting end of the second compensation capacitor

Third compensation capacitor of transmitting terminal

One end of the first compensating capacitor is connected with the other end of the second compensating capacitor

Another end of and a transmitting end coil L₁One end of the first compensating capacitor C is connected in series, and the transmitting end of the first compensating capacitor C is connected in series₀Another end, transmitting end coil L₁The other ends of the two ends are connected with an input voltage U_inNegative pole, transmitting end coil L₁And a receiving end coil L₂Are electromagnetically coupled, the mutual inductance of the coupling coil is M, and the receiving end coil L₂Receiving end compensation capacitor C₂Equivalent load R_LForming a series loop with a current I in the coil at the transmitting end₁The current in the series loop in which the receiving end coil is located is I₂The voltage across the equivalent load is U_out。

6. The output voltage adjustment method of the wireless charging system according to any one of claims 1 to 5, characterized in that: the method comprises the following steps in sequence:

(1) establishing a circuit model of the wireless charging system based on the standard LCC-S compensation topology and the improved LCC-S compensation topology respectively, analyzing the relation between the voltage gain of the wireless charging system of the standard LCC-S compensation topology and the parameter value of a compensation element, and analyzing the relation between the parameter of the compensation element and the inductance of a coil when the system works in a resonance state; analyzing the relationship between the voltage gain of the wireless charging system of the improved LCC-S compensation topology and the parameter value of the compensation element, and analyzing the relationship between the parameter of the compensation element and the coil inductance when the system works in a resonance state; the standard LCC-S compensation topology means that a transmitting end compensation network adopts a standard LCC compensation topology, and a receiving end compensation network adopts a series compensation topology; the improved LCC-S compensation topology means that the transmitting end compensation network adopts the improved LCC compensation topology, and the receiving end compensation network adopts the series compensation topology;

(2) according to different compensation topologies adopted by a system transmitting end, respectively designing a numerical value gear of a transmitting end compensation element parameter of the wireless charging system with a standard LCC-S compensation topology and a numerical value gear of a transmitting end compensation element parameter of the wireless charging system with an improved LCC-S compensation topology according to the relation between corresponding voltage gain and the compensation element parameter value;

(3) designing a corresponding switching controller according to a compensation topology adopted by a system transmitting end: firstly, transmitting a collected central position signal of a receiving and transmitting end coil to a switching controller so as to start/stop supplying power to a transmitting end coil; secondly, inputting the collected input current signal of the transmitting end into a switching controller, and calculating the current output voltage gain according to the input voltage value of the transmitting end, the coil inductance and the load resistance value; then, transmitting the obtained voltage gain signal to a switching controller, comparing a standard voltage gain value with an actual voltage gain signal fed back in real time, determining a target value gear of the compensation element, and sending a compensation element target value gear signal to a compensation element parameter regulator; and finally, the compensation element parameter regulator sends out an instruction for switching the compensation element parameters, and controls the adjustable inductor, the capacitor or the compensation element control switch to switch the corresponding compensation inductor or capacitance value, so as to realize the control of the compensation element parameter regulation of the wireless charging system.

7. The output voltage adjustment method of the wireless charging system according to claim 6, wherein: analyzing the relationship between the voltage gain of the wireless charging system with the improved LCC-S compensation topology and the parameter value of the compensation element in the step (1), and analyzing the relationship between the parameter of the compensation element and the inductance of the coil when the system works in a resonance state specifically means that:

output voltage gain H_uThe relation between the parameters of the compensation element and the inductance of the coil is as follows:

where ω is the system operating frequency, L₀Compensation of inductance for the transmitting end, C_tIs equal to L₀A compensation capacitor connected in series; λ 1/(ω)²L₀C_t) To compensate for capacitance C_tAdjusting the coefficient; in the improved LCC-S compensation topology, if the system input voltage and the series compensation inductance L₀If the relationship is kept unchanged, the relationship is simplified as follows:

H_uL₀/M₀＝μ·p

wherein, mu-1/(1-lambda) is compensation coefficient of mutual inductance variation of the coupling coil, and p-M/M₀For mutual inductance variation coefficient, M and M₀The mutual inductance of the coupling coils at the current position and the position opposite to the coil at the receiving and transmitting end is respectively;

analyzing the relationship between the voltage gain of the wireless charging system with the standard LCC-S compensation topology and the parameter value of the compensation element in the step (1), and analyzing the relationship between the parameter of the compensation element and the coil inductance when the system works in the resonance state specifically means:

output voltage gain H_uThe relation between the parameters of the compensation element and the inductance of the coil is as follows:

wherein M is the mutual inductance of the coupling coil at the current position, L₀The inductance is compensated for the transmitting end.

8. The output voltage adjustment method of the wireless charging system according to claim 6, wherein: the step (2) of designing the numerical value gear of the parameter of the transmitting end compensation element of the wireless charging system with the improved LCC-S compensation topology specifically comprises the following steps:

when the mutual inductance fluctuation of the coupling coil is caused by the coil offset of the transmitting and receiving ends, the mutual inductance value at the current position is assumed as follows: m_i＝p_iM₀，p_iThe mutual inductance variation coefficient is used for adjusting the output voltage gain of the system by changing the compensation capacitance value of the transmitting end; let the capacitance C of the current gear_ti＝q_iC₀At the initial resonant frequency, C_tThe variation of the value is expressed as a capacitance adjustment coefficient lambda_iAnd mutual inductance variation compensation coefficient mu_iThe change of (2):

wherein i is the gear at which the compensation element is currently located, and q is the capacitor C_tA scaling factor of (c); meanwhile, to satisfy the resonance condition, the capacitor needs to be adjusted synchronously

And

comprises the following steps:

thus, reference is made to the capacitance C₁And a capacitor C_tiAre connected in series to obtain a capacitor

Through the mutual inductance variation coefficient p of the coupling coil_iAnd mutual inductance variation compensation coefficient mu_iDetermining the required value gear i of the compensating element so as to obtain the compensating capacitor C_t、

And

the numerical values of the gears; wherein,

compensating capacitors C for the transmitting terminals, respectively₀、C₁The value after gear adjustment;

the step (2) of designing the numerical value gear of the parameter of the transmitting end compensation element of the wireless charging system with the standard LCC-S compensation topology specifically comprises the following steps:

when the mutual inductance fluctuation of the coupling coil is caused by the coil offset of the transmitting and receiving ends, the mutual inductance value at the current position is assumed as follows: m_i＝p_iM₀，p_iThe mutual inductance variation coefficient is obtained, and the system output voltage gain is as follows:

wherein

Compensating the inductance L for the transmitting end₀The value after gear adjustment; at this time, the compensation inductance value of the transmitting terminal can be changed

Thereby regulating the output of the systemVoltage gain:

wherein i is a compensation capacitor

The value of a is the compensation inductance

The adjustment coefficient of (2) represents the mutual inductance value of the coupling coil of the current gear and the mutual inductance value L of the initial moment₀The ratio of (A) to (B); meanwhile, in order to make the system work in a resonance state, the compensation capacitor needs to be synchronously adjusted

Thus, the initial capacitance C₁And a capacitor C_String＝C₀/(1-p) are connected in series to obtain a capacitor

Through the mutual inductance variation coefficient p of the coupling coil_iAnd voltage gain, determining the required value gear i of the compensation element, thereby obtaining the compensation inductance

And a capacitor

The numerical values of the respective gears.

9. The output voltage adjustment method of the wireless charging system according to claim 6, wherein: in step (3), designing the transmission-side compensation element switching controller according to the improved LCC-S compensation topology specifically includes the following steps:

3a1) starting control:

in the process that the receiving end coil gradually approaches to the transmitting end coil, when the position sensor arranged on the front end side of the transmitting end coil detects that the receiving end coil arrives, the position sensor sends a starting signal and transmits the starting signal to the switching controller to control the initial compensation network to be connected into the main circuit, and the corresponding transmitting end coil is in a power supply state; when the position sensor arranged on the rear end side of the transmitting end coil detects that the receiving end coil is completely separated, the coil position sensor sends out a termination signal and transmits the termination signal to the switching controller, at the moment, the compensation network is cut off, and the corresponding transmitting end coil is in an idle state;

3b1) system input current detection and feedback control:

in the improved LCC-S compensation topology, the relationship between the system input current and the voltage gain is:

wherein, ξ_i＝H_u/H_u0＝μ_ip_iFor the system output voltage gain factor, H_u0Is a reference value of voltage gain, and in the current detection and switching control procedure, the voltage gain coefficient when the receiving and transmitting end coil is over against is used as the reference value ξ₀Order ξ_i＝ξ₀＝1；

3c1) The parameter switching of the compensation element controlled in the step (3) is specifically as follows: determining the upshifting/downshifting operation of the value of the compensating element according to the compensating element target value gear signal sent by the switching controller; the adjustable capacitor or the compensation element control switch is controlled by the compensation element parameter regulator to switch the value of the compensation capacitor at the transmitting end, and the compensation capacitor C of the corresponding value gear is switched_t、

The power transmission module is connected to the power transmission module;

in step (3), designing the transmitting terminal compensation element switching controller according to the standard LCC-S compensation topology specifically includes the following steps:

3a2) starting control:

in the process that the receiving end coil gradually approaches to the transmitting end coil, when the position sensor arranged on the front end side of the transmitting end coil detects that the receiving end coil arrives, the position sensor sends a starting signal and transmits the starting signal to the switching controller to control the initial compensation network to be connected into the main circuit, and the corresponding transmitting end coil is in a power supply state; when the position sensor arranged on the rear end side of the transmitting end coil detects that the receiving end coil is completely separated, the coil position sensor sends out a termination signal and transmits the termination signal to the switching controller, at the moment, the compensation network is cut off, and the corresponding transmitting end coil is in an idle state;

3b2) system input current detection and feedback control link

In the LCC-S compensation topology, the relationship between the system input current and the voltage gain is as follows:

wherein, κ_i＝H_u/H_u0＝p_i/a_iFor the system output voltage gain factor, H_u0A reference value that is a voltage gain; in the current detection and switching control link, the voltage gain coefficient when the transmitting and receiving end coil is aligned is used as the reference value k₀Let κ be_i＝κ₀＝1；

3c2) The compensation element switch controlled in the step (3) is specifically: determining the upshifting/downshifting operation of the value of the compensating element according to the compensating element target value gear signal sent by the switching controller; the adjustable inductor, the capacitor or the compensation element control switch is controlled by the compensation element parameter adjuster to switch the values of the compensation inductor and the capacitor at the transmitting end, and the compensation inductor of the corresponding value gear is switched

And supplementCompensated capacitor

Connected to the power transfer module.

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