A parameter compensation method for LCC-S type wireless power transmission system

Abstract

The invention proposes a parameter compensation method for an LCC-S type wireless power transmission system, relates to the technical field of wireless power transmission, and solves the problems of complex steps for selecting a compensation coefficient and weak anti-offset performance of output power in the parameter compensation method of the current wireless power transmission system. The system comprises a primary circuit module and a secondary circuit module, the secondary circuit module is equivalent to the primary circuit module, and then the circuit elements in the primary circuit module are resonated so that the primary circuit is a pure resistive impedance circuit, and the compensation coefficients of the circuit elements in the primary circuit module are associated with the output power of the system by using a functional relationship, and finally the value of the circuit element corresponding to the minimum fluctuation rate is selected, and the value is set as the optimal parameter of the system, the selection step of the compensation coefficient is optimized, the output power fluctuation range is reduced, the stability of the system output power is achieved within a certain coupling coefficient variation range, and the anti-offset performance of the output power is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless power transmission, and in particular to a parameter compensation method for an LCC-S type wireless power transmission system. Background Art

[0002] Wireless power transmission systems have been widely used in electric vehicles, consumer electronics and other fields due to their many advantages such as safety, electrical isolation, low maintenance and portability. In wireless power transmission systems, the output power is sensitive to changes in the coupling coefficient, and the coupling coefficient changes dynamically during the power transmission process. If the output of the wireless power transmission system cannot reduce the sensitivity to changes in the coupling coefficient, the output power will change with the change in the coupling coefficient. Once the output power changes, the wireless power transmission system will not be able to obtain electrical energy stably. Therefore, it is of great significance to study the self-regulation of the coupling coefficient change through the wireless power transmission system's own system parameters.

[0003] Traditional wireless power transmission systems usually use LCC-S circuit control to stabilize the output of the wireless power transmission system. On the one hand, the current of the transmitting coil of the traditional LCC-S circuit is only related to the input voltage and compensation capacitance, that is, when the coupling coefficient of the wireless power transmission system changes, the current of the transmitting coil cannot adjust itself to maintain the output stability of the LCC-S circuit; on the other hand, the output power of the LCC-S circuit is proportional to the square of the mutual inductance coefficient. When the coils are physically offset, the mutual inductance coefficient between the coils will be significantly reduced, that is, the coupling coefficient is significantly reduced, resulting in a significant reduction in output power. Therefore, the traditional LCC-S circuit has weak anti-offset performance. In order to solve the above The problem is that the prior art discloses a parameter compensation method for an anti-offset LCC-S type wireless power transmission system, which utilizes two freely adjustable variable factors to optimize the design of the compensation network parameters of the wireless power transmission system, so that the system can automatically adjust the transmission current of the primary coil, and achieve an anti-offset effect of an output power fluctuation of no more than 10% through self-adjustment of the compensation network within the setting range of the coupling coefficient, thereby maintaining a relatively stable output power. However, there is no specific functional relationship between the two variable factors and between the two variable factors and the output power. The optimal value is selected only by continuously enumerating the values ​​of the variable factors. The steps for selecting the optimal values ​​of the two variable factors are complicated, and the output power fluctuation range is large. Summary of the invention

[0004] In order to solve the problems of complex steps for selecting compensation coefficients and weak anti-offset performance of output power in the current parameter compensation method of wireless power transmission system, the present invention proposes a parameter compensation method for LCC-S type wireless power transmission system, which associates the compensation coefficient with the output power by using a functional relationship, optimizes the steps for selecting the compensation coefficient, reduces the output power fluctuation range, and improves the anti-offset performance of the output power.

[0005] In order to achieve the above technical effects, the technical solution of the present invention is as follows:

[0006] A method for compensating parameters of an LCC-S type wireless power transmission system, wherein the LCC-S type wireless power transmission system comprises a primary circuit module and a secondary circuit module, wherein the primary circuit module comprises an AC voltage source, a compensation inductor L 1 , the first compensation capacitor C 1 , the second compensation capacitor C p , and the transmitting coil L P , the second compensation capacitor C p and the transmitting coil L P After being connected in series with the first compensation capacitor C 1 In parallel, the positive pole of the AC voltage source is connected to the compensation inductor L 1 One end of the compensation inductor L 1 The other end is connected to the first compensation capacitor C 1 One end of the first compensation capacitor C 1 The other end is connected to the negative pole of the AC voltage source; the secondary circuit module includes a receiving coil L connected in series in sequence S , the third compensation capacitor C S , and load R L , transmitting coil L P With receiving coil L S The mutual inductance between them is M, and the coupling coefficient is k;

[0007] The LCC-S type wireless power transmission system parameter compensation method comprises the following steps:

[0008] S1. Obtain the equivalent resonant circuit of the primary circuit module of the LCC-S type wireless power transmission system;

[0009] S2. Assume that the input impedance of the equivalent resonant circuit of the primary circuit module is Z in , according to the components in the equivalent resonant circuit, determine the input impedance Z in , further solve the compensation inductance L 1 ;

[0010] S3. Assume the output power of the system is P OUT , according to the input impedance Z in Determine the output power P OUTExpression of

[0011] S4. Select the rated coefficient interval of the coupling coefficient k;

[0012] S5. Calculate the output power P within the rated coefficient range selected in S4. OUT volatility;

[0013] S6. Determine the output power P OUT Is the volatility of the minimum value in the rated coefficient range? If so, then the L obtained by S3 1 If the system parameter compensation requirement is met, execute step S7; otherwise, return to step S1;

[0014] S7. Based on output power P OUT The fluctuation rate of the first compensation capacitor C corresponding to the minimum fluctuation rate is determined 1 The value of the first compensation capacitor C 1 The value of is set as the optimal parameter of the system.

[0015] In this technical solution, firstly based on the LCC-S type wireless power transmission system, the system includes a primary circuit module and a secondary circuit module, and then the equivalent resonant circuit of the primary circuit module of the wireless power transmission system is obtained, and the input impedance Z is determined according to the components in the equivalent resonant circuit. in And solve the compensation inductance L 1 , then the output power P OUT Based on the expression of , determine the rated coefficient interval, and calculate the output power P within the rated coefficient interval OUT The fluctuation rate of the output power P OUT The volatility is the minimum value in the rated coefficient range, so the obtained L 1 The system parameter compensation requirement is met. Finally, the first compensation capacitor C corresponding to the minimum fluctuation rate is selected. 1 The value of is set as the optimal parameter of the system, and the compensation coefficient and output power are cleverly associated using the functional relationship, which optimizes the selection steps of the compensation coefficient, reduces the output power fluctuation range, achieves the stability of the system output power within a certain coupling coefficient change range, and improves the anti-offset performance of the output power.

[0016] Preferably, in step S1, the specific steps of obtaining the equivalent resonant circuit of the primary circuit module of the system are:

[0017] S11. Resonate the receiving coil L of the secondary circuit module S And the third compensation capacitor C S It is equivalent to the reflected impedance Zr, and the reflected impedance Zr is connected in series to the transmitting coil L of the primary circuit module P middle;

[0018] S12. Make the second compensation capacitor C of the primary circuit module P and the transmitting coil L P Resonance, so that C P and L P The reactance is added to 0, and the first compensation capacitor C 1 And the reflected impedance Zr is equivalent to the parallel impedance Z 1 , and obtain the equivalent resonant circuit of the primary circuit module of the system.

[0019] Preferably, in step S2, the Z in The expression is:

[0020]

[0021] Taking the purely resistive impedance circuit as the constraint condition of expression (1), let Z in The imaginary part of expression (1) is 0, so Z in The expression (1) is transformed into:

[0022]

[0023] Preferably, the specific expression of the constraint condition is:

[0024]

[0025] Based on the constraint condition of formula (3), the expression of compensation inductance L1 is obtained as follows:

[0026]

[0027] Preferably, in step S3, the output power P OUT The specific expression is:

[0028]

[0029] Among them, U in Indicates the input voltage.

[0030] Preferably, in step S4, the rated coefficient interval of the coupling coefficient k is selected from the coupling coefficient variation range of the common coil.

[0031] Preferably, in step S7, the first compensation capacitor C corresponding to the minimum fluctuation rate is determined. 1 Before determining the maximum output power P max The value of the corresponding mutual inductance is M 2 , mutual inductance M 2 The specific expression is:

[0032]

[0033] According to the mutual inductance M 2 The specific expression of the fourth compensation capacitor C is solved Z The value of .

[0034] Preferably, in step S7, the output power P OUT The calculation expression of volatility D is:

[0035]

[0036] Among them, P O Indicates the actual output power.

[0037] Preferably, when calculating the first compensation capacitor C corresponding to the minimum fluctuation rate 1 Before the value of the output power P OUT The second objective function is derived with respect to the mutual inductance M, and its derivative is set to 0, and the maximum output power P is obtained. max The value of the mutual inductance M 2 , then the maximum output power P max The value of the mutual inductance M 2 The specific expression is:

[0038]

[0039] The maximum output power P max The value of the mutual inductance M 2 Substitute the value of into equation (12) and solve to obtain the mutual inductance M 2 Corresponding to the fourth compensation capacitor C Z The value of .

[0040] Preferably, S71. Obtain a fourth compensation capacitor C Z The value of and the step value m;

[0041] S72. Calculate the fourth compensation capacitor C Z The corresponding output power P OUT The volatility D 1 , and set the fourth compensation capacitor C Z The value of the first compensation capacitor C 1 The value of

[0042] S73. Let the first compensation capacitor C 1 The value of m is increased to obtain the first compensation capacitor C 1 The increased value C 2 ;

[0043] S74. Calculate the first compensation capacitance C 1 The increased value C 2 The corresponding output power P OUT The volatility D 2 , and judge D2 Is it less than or equal to D 1 If yes, then return to step S73; otherwise, let C 2 The value of m is reduced to get C 2 The reduced value C 3 , execute step S75;

[0044] S75. Judgment C 3 Is the value greater than C Z If the value is, then C will be output 3 The value of the first compensation capacitor C corresponding to the minimum fluctuation rate is set 1 value, and the first compensation capacitor C 1 The value of is set as the optimal parameter of the system; otherwise, execute step S76;

[0045] S76. Order C 3 The value of m is reduced to get C 3 The reduced value C 4 ;

[0046] S77. Calculate C 4 The corresponding output power P OUT The volatility D 3 , and judge D 3 Is it less than or equal to D 1 If yes, then return to step S76; otherwise, let C 4 The value increases by m, and the output is C 4 The increased value C 5 , will output C 5 The value of the first compensation capacitor C corresponding to the minimum fluctuation rate is determined 1 value, and the first compensation capacitor C 1 The value of is set as the optimal parameter of the system.

[0047] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0048] The present invention proposes a parameter compensation method for an LCC-S type wireless power transmission system. First, based on the LCC-S type wireless power transmission system, the system includes a primary circuit module and a secondary circuit module. Then, an equivalent resonant circuit of the primary circuit module of the wireless power transmission system is obtained, and the input impedance Z is determined according to the components in the equivalent resonant circuit. in And solve the compensation inductance L 1 , then the output power P OUT Based on the expression of , determine the rated coefficient interval, and calculate the output power P within the rated coefficient interval OUT The fluctuation rate of the output power P OUT The volatility is the minimum value in the rated coefficient range, so the obtained L1 The system parameter compensation requirement is met. Finally, the first compensation capacitor C corresponding to the minimum fluctuation rate is selected. 1 The value of is set as the optimal parameter of the system, and the compensation coefficient and output power are cleverly associated using the functional relationship, which optimizes the selection steps of the compensation coefficient, reduces the output power fluctuation range, achieves the stability of the system output power within a certain coupling coefficient change range, and improves the anti-offset performance of the output power. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A schematic diagram showing a flow chart of a parameter compensation method for an LCC-S type wireless power transmission system proposed in an embodiment of the present invention;

[0050] Figure 2 A circuit structure diagram showing an LCC-S type wireless power transmission system proposed in an embodiment of the present invention;

[0051] Figure 3 shows a first equivalent circuit diagram proposed in an embodiment of the present invention;

[0052] Figure 4 A second equivalent circuit diagram proposed in an embodiment of the present invention is shown;

[0053] Figure 5 An equivalent resonant circuit diagram proposed in an embodiment of the present invention is shown;

[0054] Figure 6 A graph showing a function Y with respect to X proposed in an embodiment of the present invention;

[0055] Figure 7 represents the output power P proposed in the embodiment of the present invention OUT About coupling coefficient k Graph of

[0056] Figure 8 represents the M proposed in the embodiment of the present invention 2 With C 1 Function curve graph of ;

[0057] Fig. 9 A diagram showing a change in the output power of the system proposed in an embodiment of the present invention;

[0058] Fig.10 A simulation diagram showing changes in system output power proposed in an embodiment of the present invention. DETAILED DESCRIPTION

[0059] The drawings are for illustrative purposes only and should not be construed as limiting the present patent;

[0060] In order to better illustrate the present embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent actual sizes. The description of the directions of parts such as "upper" and "lower" does not limit the present patent;

[0061] It is understandable to those skilled in the art that some well-known contents may be omitted in the drawings;

[0062] The positional relationships described in the drawings are only for illustrative purposes and should not be construed as limiting the present patent.

[0063] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0064] Example 1

[0065] like Figure 1 and Figure 2 As shown, this embodiment proposes a parameter compensation method for an LCC-S type wireless power transmission system, wherein the LCC-S type wireless power transmission system includes a primary circuit module and a secondary circuit module, wherein the primary circuit module includes an AC voltage source, a compensation inductor L 1 , the first compensation capacitor C 1 , the second compensation capacitor C p , and the transmitting coil L P , the second compensation capacitor C p and the transmitting coil L P After being connected in series with the first compensation capacitor C 1 In parallel, the positive pole of the AC voltage source is connected to the compensation inductor L 1 One end of the compensation inductor L 1 The other end is connected to the first compensation capacitor C 1 One end of the first compensation capacitor C 1 The other end is connected to the negative pole of the AC voltage source; the secondary circuit module includes a receiving coil L connected in series in sequence S , the third compensation capacitor C S , and load R L , transmitting coil L P With receiving coil L S The mutual inductance between them is M, and the coupling coefficient is k;

[0066] The LCC-S type wireless power transmission system parameter compensation method comprises the following steps:

[0067] S1. Obtain the equivalent resonant circuit of the primary circuit module of the LCC-S type wireless power transmission system;

[0068] In step S1, the specific steps of obtaining the equivalent resonant circuit of the primary circuit module of the system are:

[0069] S11. Resonate the receiving coil L of the secondary circuit module S And the third compensation capacitor C S It is equivalent to the reflected impedance Zr, and the reflected impedance Zr is connected in series to the transmitting coil L of the primary circuit module P In the first equivalent circuit diagram, the calculation expression of the reflected impedance Zr in the first equivalent circuit diagram is:

[0070]

[0071] Wherein, ω represents the system angular frequency, satisfying ω=2πf, and f represents the operating frequency of the system.

[0072] S12. Make the second compensation capacitor C of the primary circuit module P and the transmitting coil L P Resonance, so that C P and L P The reactance is added to 0, and the first compensation capacitor C 1 And the reflected impedance Zr is equivalent to the parallel impedance Z 1 , get the equivalent resonant circuit of the primary circuit module of the system; in the resonant second compensation capacitor C P and the transmitting coil L P The following conditions must be met:

[0073]

[0074] See also Figure 4 , the second compensation capacitor C of the primary circuit module P and the transmitting coil L P Resonance is eliminated, and the second equivalent circuit diagram is obtained, see Figure 5 , connect the first compensation capacitor C in parallel 1 And the reflected impedance Zr is equivalent to the parallel impedance Z 1 , we get the equivalent resonant circuit, where the parallel impedance Z 1 The calculation expression is:

[0075]

[0076] S2. Assume that the input impedance of the equivalent resonant circuit of the primary circuit module is Z in , according to the components in the equivalent resonant circuit, determine the input impedance Z in , further solve the compensation inductance L 1 ;

[0077] S3. Assume the output power of the system is P OUT , according to the input impedance Z in Determine the output power P OUT Expression of

[0078] S4. Select the rated coefficient interval of the coupling coefficient k;

[0079] S5. Calculate the output power P within the rated coefficient range selected in S4. OUT volatility;

[0080] S6. Determine output power P OUT Is the volatility of the minimum value in the rated coefficient range? If so, then the L obtained by S3 1 If the system parameter compensation requirement is met, execute step S7; otherwise, return to step S1;

[0081] S7. Based on output power P OUT The fluctuation rate of the first compensation capacitor C corresponding to the minimum fluctuation rate is solved 1 The value of the first compensation capacitor C 1 The value of is set as the optimal parameter of the system.

[0082] In this embodiment, firstly, based on the LCC-S type wireless power transmission system, the system includes a primary circuit module and a secondary circuit module, and then the equivalent resonant circuit of the primary circuit module of the wireless power transmission system is obtained, and the input impedance Z is determined according to the components in the equivalent resonant circuit. in And solve the compensation inductance L 1 , then the output power P OUT Based on the expression of , determine the rated coefficient interval, and calculate the output power P within the rated coefficient interval OUT The fluctuation rate of the output power P OUT The volatility is the minimum value in the rated coefficient range, so the obtained L 1 The system parameter compensation requirement is met. Finally, the first compensation capacitor C corresponding to the minimum fluctuation rate is selected. 1 The value of is set as the optimal parameter of the system, and the compensation coefficient and output power are cleverly associated using the functional relationship, which optimizes the selection steps of the compensation coefficient, reduces the output power fluctuation range, achieves the stability of the system output power within a certain coupling coefficient change range, and improves the anti-offset performance of the output power.

[0083] Example 2

[0084] See also Figure 1 In step S2, the input impedance Z is determined according to the components in the equivalent resonant circuit. in , input impedance Z in The specific calculation steps are:

[0085] S21. Get Z in About L 1 and Z 1The initial expression relationship is:

[0086] Z in =jωL 1 +Z 1 (0.4)

[0087] S22. Substitute equation (0.1) and equation (0.3) into equation (0.4) to simplify and obtain the input impedance Z in The expression is:

[0088]

[0089] Taking the purely resistive impedance circuit as the constraint condition of expression (1), let Z in The imaginary part of expression (1) is 0, so Z in The expression (1) is transformed into:

[0090]

[0091] The constraints are specifically expressed as:

[0092]

[0093] Based on the constraint condition of formula (3), the expression of compensation inductance L1 is obtained as follows:

[0094]

[0095] In step S3, the output power P OUT The specific expression is:

[0096]

[0097] Among them, U in represents the input voltage. The specific solution process of formula (5) is as follows: First, obtain the output power P OUT The initial expression of is:

[0098]

[0099] Then substitute equation (2) into the expression (5.1) of the first objective function and simplify it to obtain the output power P OUT The specific expression of .

[0100] The traditional expression for output power under ideal conditions of resonance is:

[0101]

[0102] Compared with formula (5.2), formula (5) shows that P OUTIt is no longer a common linear relationship with the mutual inductance M. We make an equivalent substitution for equation (5) and set the equivalent condition as follows:

[0103]

[0104]

[0105] Substituting equation (5.3) and equation (5.4) into equation (5), equation (5) is transformed into:

[0106]

[0107] Where Y represents P OUT , X represents M, meaning a set of numbers A = 2000, B = 2, see Figure 6 , make a graph of function Y with respect to X, by Figure 6 It is known that function Y changes smoothly within the maximum value range.

[0108] In step S4, the rated coefficient interval of the coupling coefficient k is selected from the coupling coefficient variation range of the ordinary coil. Within the selected rated coefficient interval, see Figure 7 In order to ensure that the power fluctuation range is small, the fluctuation rate of the output power in the system depends on the largest difference between the maximum and minimum output power and the rated output power in the entire coupling coefficient interval. Therefore, it is necessary to select and determine a suitable rated coefficient interval so that the difference between the output power Pnom in the rated coefficient interval and the maximum output power Pmax and the minimum output power Pmin is minimized; the specific expression of the coupling coefficient k is:

[0109]

[0110] The maximum output power P max The coupling coefficient k corresponding to the value of is located at the midpoint of the rated coefficient range.

[0111] Example 3

[0112] In step S7, the first compensation capacitor C corresponding to the minimum fluctuation rate is determined. 1 Before determining the maximum output power P max The value of the corresponding mutual inductance is M 2 , mutual inductance M 2 The specific expression is:

[0113]

[0114] The output power P OUT By taking the derivative of expression (5) with respect to the mutual inductance M and setting its derivative to 0, we can obtain equation (7). 2 The specific expression (7) is solved for the fourth compensation capacitor CZ The value of .

[0115] The input voltage U in The value of the operating frequency f, the system angular frequency ω corresponding to the operating frequency f, and the load R L The value R and the value M of the mutual inductance 1 , Substitute into formula (4) and transform (4) into:

[0116]

[0117] Take the input voltage U in =60V, operating frequency f=200kHz, load R L The value of R = 20Ω, the primary transmitting coil inductance L P =64uH, secondary receiving coil inductance L S =64uH, the rated coefficient range of the coupling coefficient k is 0.23-0.35, and the value range of M is 14.685-22.347 using formula (6). The coupling coefficient k = 0.35 is the best working state of the coil. The mutual inductance M of the best working state is obtained using formula (6) = 22.347uH. The mutual inductance M corresponding to the maximum output power is 2 The value of is at the midpoint of the M value range, that is, the mutual inductance M corresponding to the maximum output power 2 is the median mutual inductance Mz, the value of Mz is 18.51uH, and M 2 =M Z =18.51uH, see Figure 8 , use formula (12) to make M 2 With C 1 The function curve of Figure 8 It is known that the median mutual inductance value Mz is 18.5uH, and the mutual inductance M 2 Corresponding to the fourth compensation capacitor C Z The value is 11.3nf;

[0118] In step S7, the output power P OUT The calculation expression of volatility D is:

[0119]

[0120] Among them, P O Indicates the actual output power.

[0121] Determine the first compensation capacitor C 1 The specific steps for the value of are:

[0122] S71. Obtain the fourth compensation capacitor C Z The value of and the step value m;

[0123] In step S71, take C Z The value of is 11.3nf, and m is 0.1nf;

[0124] S72. Calculate the fourth compensation capacitor C Z The corresponding output power P OUT The volatility D 1 , and set the fourth compensation capacitor C Z The value of the first compensation capacitor C 1 The value of E

[0125] In step S72, the maximum output power Pmax, the minimum output power Pmin and the rated power Pnom corresponding to the capacitor Cz are respectively obtained using formula (5), and |Pmax-Pnom|=A1, |Pnom-Pmin|=A2 are obtained, and the maximum value of the two is taken as A. The fluctuation rate D corresponding to the output power is obtained using formula (8). 1 .

[0126] S73. Let the first compensation capacitor C 1 The value of m is increased to obtain the first compensation capacitor C 1 The increased value C 2 ;

[0127] S74. Calculate the first compensation capacitor C using formula (13) 1 The increased value C 2 The corresponding output power P OUT The volatility D 2 , and judge D 2 Is it less than or equal to D 1 If yes, then return to step S73; otherwise, let C 2 The value of m is reduced to get C 2 The reduced value C 3 , execute step S75;

[0128] S75. Judgment C 3 Is the value greater than C Z If the value is, then the output is C 3 The value of the first compensation capacitor C corresponding to the minimum fluctuation rate is set 1 value, and the first compensation capacitor C 1 The value of is set as the optimal parameter of the system; otherwise, execute step S76;

[0129] S76. Order C 3 The value of m is reduced to get C 3 The reduced value C 4 ;

[0130] S77. Calculate C using formula (13) 4 The corresponding output power POUT The volatility D 3 , and judge D 3 Is it less than or equal to D 1 If yes, then return to step S76; otherwise, let C 4 The value increases by m, and the output is C 4 The increased value C 5 , output C 5 The value of the first compensation capacitor C corresponding to the minimum fluctuation rate is set 1 value, and the first compensation capacitor C 1 The value of is set as the optimal parameter of the system.

[0131] In this embodiment, the first compensation capacitor C 1 The value of is 11.7nf, the value of L1 is 18.318, and the voltage U in =60V, primary transmitting coil inductance L P =64uH, secondary receiving coil inductance L S =64uH, load R L The value of R = 20Ω, operating frequency f = 200kHz, Kmin = 0.23, Kmax = 0.35, see Fig. 9 , respectively, when k = 0.296, the maximum output power Pmax = 95.86W corresponding to Cz, when k = 0.23, the minimum output power Pmin = 85.04W corresponding to Cz, and when k = 0.35, the output power P OUT =85.04W, rated power Pnom=90W, take A=5.85W, and the corresponding fluctuation rate deviation is about 6.5%;

[0132] See also Fig.10 , simulated on PSIM, set input voltage Uin = 60V, operating frequency f = 200KHz, working load R = 20Ω, primary compensation inductor L1 = 18.318uH, primary compensation capacitor C1 = 11.7nF, primary inductor LP = 63.7uH, secondary inductor LS = 64uH, set the coupling coefficient k = 0.35 as the best working state, see Figure 8 The simulation results show that when the system k=0.35, the output power is 95W. When the coupling coefficient k value decreases, the maximum output power is 101.13W, the minimum output power is 88.86W, and the output power fluctuation rate of the system is 6.51%. This shows that the present embodiment can achieve an anti-offset effect of an output power fluctuation of no more than 7% when the coupling coefficient k is within 0.23-0.35, which is obviously better than the anti-offset effect of the traditional technology with an output power fluctuation of no more than 10%. It can achieve output power stability within a certain coupling coefficient variation range, verifying the feasibility and excellent effect of the method of the present invention.

[0133] Obviously, the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A parameter compensation method for an LCC-S type wireless power transmission system, wherein the LCC-S type wireless power transmission system comprises a primary circuit module and a secondary circuit module, wherein the primary circuit module comprises an AC voltage source, a compensation inductor L 1 , the first compensation capacitor C 1 , the second compensation capacitor C p , and the transmitting coil L P , the second compensation capacitor C p and the transmitting coil L P After being connected in series with the first compensation capacitor C 1 In parallel, the positive pole of the AC voltage source is connected to the compensation inductor L 1 One end of the compensation inductor L 1 The other end is connected to the first compensation capacitor C 1 One end of the first compensation capacitor C 1 The other end is connected to the negative pole of the AC voltage source; the secondary circuit module includes a receiving coil L connected in series in sequence S , the third compensation capacitor C S , and load R L , transmitting coil L P With receiving coil L S The mutual inductance between them is M, and the coupling coefficient is k ; It is characterized in that The LCC-S type wireless power transmission system parameter compensation method comprises the following steps: S1. Obtain the equivalent resonant circuit of the primary circuit module of the LCC-S type wireless power transmission system; S2. Assume that the input impedance of the equivalent resonant circuit of the primary circuit module is Z in , according to the components in the equivalent resonant circuit, determine the input impedance Z in , further solve the compensation inductance L 1 ; S3. Assume the output power of the system is P OUT , according to the input impedance Z in Determining Output Power P OUT Expression of S4. Select the rated coefficient interval of the coupling coefficient k; S5. Calculate the output power within the rated coefficient range selected in S4. P OUT volatility; S6. Determine output power P OUT Is the volatility of the minimum value in the rated coefficient range? If so, then the L obtained by S3 1 If the system parameter compensation requirement is met, execute step S7; otherwise, return to step S1; S7. Based on output power The fluctuation rate of the first compensation capacitor C corresponding to the minimum fluctuation rate is solved 1 The value of the first compensation capacitor C 1 The value of is set as the optimal parameter of the system; In determining the first compensation capacitor C corresponding to the minimum fluctuation rate 1 Before determining the maximum output power P max The value of the corresponding mutual inductance is M 2 , mutual inductance M 2 The specific expression is: （7） Wherein, M1 represents the value of mutual inductance M; According to the mutual inductance M 2 The specific expression of the fourth compensation capacitor C is solved Z The value of Determine the first compensation capacitor C 1 The specific steps for the value of are: S71. Obtain the fourth compensation capacitor C Z The value of and the step value m; S72. Calculate the fourth compensation capacitor C Z The corresponding output power P OUT The volatility D 1 , and set the fourth compensation capacitor C Z The value of the first compensation capacitor C 1 The value of S73. Let the first compensation capacitor C 1 The value of m is increased to obtain the first compensation capacitor C 1 The increased value C 2 ; S74. Calculate the first compensation capacitance C 1 The increased value C 2 The corresponding output power P OUT The volatility D 2 , and judge D 2 Is it less than or equal to D 1 If yes, then return to step S73; otherwise, let C 2 The value of m is reduced to get C 2 The reduced value C 3 , execute step S75; S75. Judgment C 3 Is the value greater than C Z If the value is, then C will be output 3 The value of the first compensation capacitor C corresponding to the minimum fluctuation rate is set 1 value, and the first compensation capacitor C 1 The value of is set as the optimal parameter of the system; otherwise, execute step S76; S76. Order C 3 The value of m is reduced to get C 3 The reduced value C 4 ; S77. Calculate C 4 The corresponding output power P OUT The volatility D 3 , and judge D 3 Is it less than or equal to D 1 If yes, then return to step S76; otherwise, let C 4 The value increases by m, and the output is C 4 The increased value C 5 , will output C 5 The value of the first compensation capacitor C corresponding to the minimum fluctuation rate is determined 1 value, and the first compensation capacitor C 1 The value of is set as the optimal parameter of the system.

2. The LCC-S type wireless power transmission system parameter compensation method according to claim 1, It is characterized in that In step S1, the specific steps of obtaining the equivalent resonant circuit of the primary circuit module of the system are: S11. Resonate the receiving coil L of the secondary circuit module S And the third compensation capacitor C S It is equivalent to the reflected impedance Zr, and the reflected impedance Zr is connected in series to the transmitting coil L of the primary circuit module P middle; S12. Make the second compensation capacitor C of the primary circuit module P and the transmitting coil L P Resonance, so that C P and L P The reactance is added to 0, and the first compensation capacitor C 1 And the reflected impedance Zr is equivalent to the parallel impedance Z 1 , and obtain the equivalent resonant circuit of the primary circuit module of the system.

3. The LCC-S type wireless power transmission system parameter compensation method according to claim 2, It is characterized in that In step S2, the Z in The expression is: （1） Taking the purely resistive impedance circuit as the constraint condition of expression (1), let Z in The imaginary part of expression (1) is 0, so Z in The expression (1) is transformed into: （2）。 4. The LCC-S type wireless power transmission system parameter compensation method according to claim 3, It is characterized in that The specific expression of the constraint condition is: （3） Based on the constraint condition of formula (3), the expression of compensation inductance L1 is obtained as follows: （4）。 5. The LCC-S type wireless power transmission system parameter compensation method according to claim 4, It is characterized in that In step S3, the output power P OUT The specific expression is: （5） Among them, U in Indicates the input voltage.

6. The parameter compensation method of the LCC-S type wireless power transmission system according to claim 5, It is characterized in that In step S4, the rated coefficient interval of the coupling coefficient k is selected from the coupling coefficient variation range of the common coil.

7. The LCC-S type wireless power transmission system parameter compensation method according to claim 6, It is characterized in that The specific expression of the coupling coefficient k is: （6） The maximum output power P max The coupling coefficient corresponding to the value of k Located in the middle of the rated coefficient range.

8. The parameter compensation method of the LCC-S type wireless power transmission system according to claim 7, It is characterized in that In step S7, the output power P OUT The calculation expression of volatility D is: （8） Among them, P O Indicates the actual output power, Indicates the output power within the rated coefficient range.

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