Method for regulated output and wireless charging receiving device

Abstract

The present application provides a method for stable voltage output. When the output voltage of the voltage stabilizing circuit (i.e., the voltage across the load) is less than a preset voltage value, the load is disconnected from the charging circuit to prevent the voltage stabilizing circuit from entering an unstable range and causing the voltage across the load to become even lower. When the output voltage of the voltage stabilizing circuit is greater than or equal to the preset voltage value, the load is reconnected to the charging circuit, so that the voltage stabilizing circuit can operate in a stable range and the output voltage on the load side can be stabilized.

Description

Technical Field

[0001] The present application relates to the field of circuits, and particularly to a method for regulated output and a wireless charging receiving device. Background Art

[0002] Omnidirectional wireless charging refers to a technology in which, within an effective charging area, the charging is less affected by distance and direction, and effective charging can be achieved in any direction. This technology is an improvement over the "patch type" wireless charging technology based on a single direction and is one of the trends in the development of future wireless charging technologies. Currently, the regulated voltage circuit on the receiving side of omnidirectional wireless charging generally adjusts the duty cycle of a direct current / direct current (DC / DC) converter through a proportion integral differential (PID) control algorithm to adjust the load output voltage and stabilize the load voltage. However, the traditional regulated voltage circuit does not consider that the AC internal resistance of the receiving side coil will cause an unstable interval where the regulated voltage function fails. At the same time, the existing wireless charging closed-loop control system is complex, expensive, and the control algorithm is complex.

[0003] Then, how to achieve the stability of the voltage on the load side has become an urgent problem to be solved. Summary of the Invention

[0004] The present application provides a method for regulated output. Compared with the traditional regulated voltage circuit, it improves the influence brought by the high AC internal resistance of the receiving side coil, avoids the unstable interval where the regulated voltage circuit fails to regulate voltage, and thus realizes the stability of the voltage on the load side. At the same time, this method does not need to be controlled by the primary side, that is, it can achieve regulated output in a large range without establishing communication with the primary side circuit.

[0005] In a first aspect, a method for regulated output is provided, including: determining whether the output voltage of a first circuit is higher than or equal to a first preset voltage value, where the output voltage is used to charge a device to be charged; when the output voltage of the first circuit is higher than or equal to the first preset voltage value, connecting the device to be charged to the first circuit; when the output voltage of the first circuit is lower than the first preset voltage value, disconnecting the device to be charged from the first circuit.

[0006] In the above technical solution, when the output voltage of the voltage stabilization circuit (i.e., the voltage across the load) is less than the preset voltage value, the load is disconnected from the charging circuit to prevent the voltage stabilization circuit from entering an unstable range and making the voltage across the load even lower; when the output voltage of the voltage stabilization circuit is greater than or equal to the preset voltage value, the load is reconnected to the charging circuit, so that the voltage stabilization circuit can work in a stable range and the voltage on the load side can be stabilized. Compared with the traditional wireless charging system and its voltage stabilization circuit, the voltage stabilization function can be achieved at a farther distance under the same conditions, and a higher internal resistance of the receiving coil is allowed, making the design range of the receiving coil wider.

[0007] In combination with the first aspect, in some implementation manners of the first aspect, when the output voltage of the first circuit is higher than or equal to the first preset voltage value and the input voltage of the first circuit is higher than or equal to the second preset voltage value, the device to be charged is connected to the first circuit, where the input voltage is used to provide voltage for the output voltage.

[0008] In combination with the first aspect, in some implementation manners of the first aspect, when the input voltage of the first circuit is higher than or equal to the second preset voltage value, the device to be charged is connected to the first circuit, where the input voltage is used to provide voltage for the output voltage, and when the input voltage of the first circuit is higher than or equal to the second preset voltage value, the output voltage of the first circuit is higher than or equal to the first preset voltage value.

[0009] In a second aspect, a wireless charging receiving device is provided, including: an induction circuit for providing voltage for the device to be charged; a rectification circuit for converting the alternating current generated by the induction circuit into direct current; a DC / DC converter for regulating the voltage of the device to be charged; a first switch connected between the positive output of the rectification circuit and the positive input of the DC / DC converter; a second switch connected between the positive output of the rectification circuit and the positive output of the DC / DC converter; and a third switch connected between the positive output of the DC / DC converter and the positive pole of the device to be charged.

[0010] In the above technical solution, a specific circuit for implementing the voltage stabilization method of the first aspect through three-switch logic control is given. The three switches are applied between the rectification circuit, the voltage stabilization circuit and its output load, and its working mode does not need to be controlled by the primary side, that is, a wide range of voltage stabilization output can be achieved without establishing communication with the primary circuit.

[0011] In combination with the second aspect, in certain implementation manners of the second aspect, the wireless charging receiving device further includes: a charging circuit connected between the second switch and the negative output terminal of the DC / DC converter. The charging circuit is configured to increase the voltage across the charging circuit to a first preset voltage value when the second switch is closed and the first switch and the third switch are open.

[0012] In combination with the second aspect, in certain implementation manners of the second aspect, the wireless charging receiving device further includes: an intelligent switch selection module configured to control the closing or opening of the first switch, the second switch, and the third switch.

[0013] In combination with the second aspect, in certain implementation manners of the second aspect, the intelligent switch selection module is a relay, and the relay includes the first switch, the second switch, and the third switch.

[0014] In a third aspect, a method for output voltage regulation is provided, which is applied to the wireless charging receiving device of the second aspect. The method includes: when the voltage across the device to be charged is less than the first preset voltage value, closing the second switch and opening the first switch and the third switch; or when the voltage across the charging circuit is greater than or equal to the first preset voltage value, opening the second switch and closing the first switch and the third switch.

[0015] In a fourth aspect, a wireless charging transmitting device is provided, including: a switch group including N switches, where N≥2 and N is an integer; an induction coil array including N coils, and the N switches are respectively corresponding to the N induction coils one by one; a power circuit configured to provide an excitation current for the induction coil array; and the power circuit, the switch group, and the induction coil array are connected in series.

[0016] In the above technical solutions, for the scenario where multiple transmitting coils work in multiple directions, the coupling effect between the receiving coil and the transmitting coil will also affect the size of the unstable interval of the voltage regulation circuit. By the magnitude of the primary current corresponding to the transmitting coil, it is possible to determine the coil in the transmitting induction coil array that has the best coupling effect with the receiving coil without primary-secondary communication, thereby reducing the size of the unstable interval of the voltage regulation circuit.

[0017] In combination with the fourth aspect, in certain implementation manners of the fourth aspect, the wireless charging transmitting device further includes: a sampling circuit configured to perform periodic sampling on the currents of the N coils; a comparison circuit configured to compare the sampled currents of the N coils to determine the minimum current among the N coils; and an intelligent switch selection module configured to determine the closing or opening of the N switches according to the minimum current among the N coils.

[0018] In combination with the fourth aspect, in some implementations of the fourth aspect, the intelligent switch selection module is a relay, and the relay includes N switches in the switch group.

[0019] Fifth aspect, a method for determining a transmitting induction coil is provided, which is applied to the wireless charging transmitting device of the fourth aspect, and includes: when the output voltage of the power circuit is the same, closing N switches in sequence at N moments, and simultaneously opening the remaining (N - 1) switches; respectively sampling the currents on N coils after the N switches are closed in sequence; determining the minimum current on the N coils according to the sampled currents on the N coils; the intelligent switch selection module closes the switch corresponding to the minimum current value, and simultaneously disconnects the remaining (N - 1) switches.

[0020] According to the solution provided in this embodiment, when the output voltage of the voltage stabilizing circuit (i.e., the voltage across the load) is less than the preset voltage value, the load is disconnected from the charging circuit to prevent the voltage stabilizing circuit from entering an unstable range and making the voltage across the load lower; when the output voltage of the voltage stabilizing circuit is greater than or equal to the preset voltage value, the load is reconnected to the charging circuit, so that the voltage stabilizing circuit can work in a stable range and the voltage on the load side can be stabilized. Description of the Drawings

[0021] Figure 1 is a schematic diagram of a traditional post-stage voltage stabilizing circuit.

[0022] Figure 2 is the variation relationship diagram between V o and D in the traditional voltage stabilizing circuit under the influence of the internal resistance of the receiving coil.

[0023] Figure 3 is a method for stabilizing the output provided in an embodiment of the present application.

[0024] Figure 4 is a schematic diagram of a three-switch wireless charging receiving device provided by the present application.

[0025] Figure 5 is a schematic diagram of a single-switch wireless charging receiving device provided by the present application.

[0026] Figure 6 is a schematic diagram of a two-switch wireless charging receiving device provided by the present application.

[0027] Figure 7 is at V o = 5 as the target stable value, the variation relationship diagram between different V s and D.

[0028] Figure 8 is a schematic diagram of a wireless charging transmitting device provided by the present application.

[0029] Figure 9 It is a schematic diagram of a three-transmitting-coil wireless charging transmitting device provided by this application.

[0030] Figure 10 A planar spiral coil design scheme proposed by this application. Specific implementation manners

[0031] Next, the technical solutions in this application will be described with reference to the accompanying drawings.

[0032] The technical solutions of the embodiments of this application can be applied to various scenarios that require wireless charging, such as intelligent wearables, electric vehicles, etc. The load has more freedom in spatial position, which is flexible and convenient.

[0033] Wireless charging technology refers to the technology that realizes non-contact power transmission through air media by means of electromagnetic induction, radio frequency, microwave, laser, etc. instead of wires. At present, there are many research results in wireless charging, and "surface-mounted" wireless charging has been commercialized and widely used in fields such as smart phones. However, since "surface-mounted" wireless charging requires the device to be closely attached to the charging board, the usage scenarios are limited. For example, when the device moves randomly, such as when a mobile phone is placed in a pocket or a watch is worn on the hand, it is difficult to achieve effective wireless charging, and the device must be placed flat on the charging board.

[0034] Omnidirectional wireless charging refers to the technology in which the charging is less affected by distance and direction within the effective charging area, and effective charging can be achieved in any direction. This technology is an improvement on the "surface-mounted" wireless charging technology based on a single direction and is one of the trends in the development of future wireless charging technology.

[0035] Currently, a control strategy of time-division multiplexing and adjustable excitation amplitude is proposed, and three-dimensional orthogonal transmitting coils are used to achieve omnidirectional wireless charging of the receiving coil. On this basis, a front-end monitoring control strategy is further proposed, so that the system can achieve omnidirectional control without sampling the signals on the receiving side. Although this strategy solves the communication problem between the transmitting side and the receiving side to a certain extent, it requires the use of an SS compensation network and requires the circuit not to work near the resonance point, which reduces the system output power and efficiency.

[0036] See Figure 1 , Figure 1This is a schematic diagram of a traditional post-stage voltage stabilization circuit. This voltage stabilization circuit adjusts the load voltage through a post-stage direct current / direct current (DC / DC) converter. The receiving side generally adjusts the voltage through rectification, filtering, and a DC / DC converter to achieve a constant output voltage on the load side. A DC / DC converter is a device that converts a DC power supply of a certain voltage level into a DC power supply of another voltage level. By collecting the output voltage value V o , the duty cycle of the DC / DC converter is adjusted through the proportional-integral-differential (PID) control algorithm to adjust the output voltage and stabilize the load voltage.

[0037] However, this method of adjusting the output voltage by adjusting the duty cycle does not take into account the AC internal resistance of the receiving coil. When the influence of the internal resistance of the receiving side induction coil is considered, Figure 1 The load voltage V o and the receiving coil induced voltage V s There are the following relationships:

[0038]

[0039] Where Vs is the induced voltage of the receiving coil, R s is the AC resistance of the receiving coil, and D is the duty cycle of the DC / DC module. e is the equivalent resistance from the load side to the input terminal of the DC / DC module, and Where η is the efficiency of the DC / DC module, R o For load.

[0040] See also Figure 2 , Figure 2 In the traditional voltage stabilization circuit, V is affected by the internal resistance of the receiving coil. o The relationship diagram between the changes in and D. Figure 2 V s =1, R s =10, R o =100, η ​​= 0.9, Figure 2 Hit the V o As D increases, this part of the interval is called the stable interval. o When D decreases as it increases, this part of the interval is called the unstable interval.

[0041] Depend on Figure 2 It can be seen that the unstable interval is located in the interval with a high duty cycle. According to the traditional PID control algorithm, the modulation method of the duty cycle of the DC / DC converter is adjusted. When the receiving side circuit is not powered and just starts to work, V oUsually it is relatively small, that is, when the system starts to work, it is necessary to quickly increase V o , at this time, the duty cycle D will be increased through PID regulation, so that the voltage stabilizing circuit is very likely to enter the unstable working range.

[0042] When Figure 1 As shown in the traditional load voltage stabilizing circuit, due to the continuous increase of the duty cycle, there is an unstable range, and the output voltage V o is lower than the voltage required for the normal operation of the load R o , the traditional load voltage stabilizing circuit will continue to increase the duty cycle of the DC / DC converter through the PID control link. As can be seen from Figure 2 , in the unstable range, the output voltage V o becomes lower instead as the duty cycle D increases, and such a cycle will not be able to achieve the voltage stabilizing effect.

[0043] In view of this, the present application proposes a receiving-side output voltage stabilizing circuit structure without feedback, which optimizes the traditional load voltage stabilizing circuit, so as to better realize the voltage stabilizing function of the load circuit.

[0044] Next, each embodiment provided by the present application will be described in detail with reference to the accompanying drawings.

[0045] Figure 3 is a method for stabilizing output provided by an embodiment of the present application.

[0046] S301, determine whether the output voltage of the first circuit is higher than or equal to the first preset voltage value. If so, jump to S302; if not, jump to S303.

[0047] S302, when the output voltage of the first circuit is higher than or equal to the first preset voltage value, connect the device to be charged to the first circuit, where the output voltage is used to charge the device to be charged.

[0048] Optionally, when the output voltage of the first circuit is higher than or equal to the first preset voltage value and the input voltage of the first circuit is higher than or equal to the second preset voltage value, connect the device to be charged to the first circuit.

[0049] Optionally, when the input voltage of the first circuit is higher than or equal to the second preset voltage value, connect the device to be charged to the first circuit, where when the input voltage of the first circuit is higher than the second preset voltage value, the output voltage of the first circuit is higher than or equal to the first preset voltage value.

[0050] S303, when the output voltage of the first circuit is lower than the first preset voltage value, disconnect the device to be charged from the first circuit.

[0051] Optionally, in S304, when the device to be charged is disconnected, charge the output voltage of the first circuit to increase the voltage value of the output voltage of the first circuit, and then jump to S301. In the above technical solution, according to the magnitude of the output voltage values between the circuits directly charging the load, it is determined whether to connect the device to be charged to the charging circuit, so as to avoid the device to be charged entering the unstable operating range when the output voltage value is small.

[0052] By way of example and not limitation, the present application provides three voltage stabilization circuits that can achieve the above-mentioned voltage stabilization output on the basis of the existing voltage stabilization circuit.

[0053] The first: the three-switch method.

[0054] See Figure 4 , Figure 4 which is a schematic diagram of a three-switch wireless charging receiving device provided by the present application.

[0055] The receiving-side wireless charging receiving device includes: an induction circuit, a rectification circuit, and a first circuit. The first circuit includes: a DC / DC converter, a first switch (S 1 ), a second switch (S 2 ), a third switch (S 3 ), a first capacitor (C o ) and a relay (i.e., an example of an intelligent gating module). Among them,

[0056] The induction circuit is used to provide voltage for the device to be charged;

[0057] The rectification circuit is used to convert the alternating current generated by the induction circuit into direct current;

[0058] The DC / DC converter is used to regulate the voltage of the device to be charged;

[0059] The relay, as a logic switch, includes two normally open contacts S 1 and S 3 , one normally closed contact S 2 and the relay coil, and is used to control the closing or opening of the first switch, the second switch, and the third switch through the conduction voltage V set of the coil in the relay;

[0060] The first switch is connected between the output positive pole of the rectification circuit and the input positive pole of the DC / DC converter;

[0061] The second switch is connected between the output positive pole of the rectification circuit and the output positive pole of the DC / DC converter;

[0062] The third switch is connected between the positive output of the DC / DC converter and the positive pole of the device to be charged;

[0063] The first capacitor is used to charge the coil in the relay.

[0064] Refer to Figure 1 It can be seen that the traditional voltage stabilizing circuit is equivalent to keeping the switches S Figure 4 in 1 and S 3 normally closed, while S 2 is kept normally open.

[0065] Specifically, when the receiving side is not working, the receiving side circuit keeps the switches S 1 and S 3 normally open, while S 2 is kept normally closed. When the receiving side starts to work, the power supply of the relay coil is provided by the output capacitor C o , and the conduction voltage value V set of the relay coil can ensure that the voltage stabilizing circuit works in a stable range. When the voltage V o across C o (i.e., the output voltage of the first circuit) rises to the conduction voltage V set of the relay coil, the switches S 1 and S 3 close, and S 2 opens. At this time, the voltage stabilizing circuit is equivalent to the traditional voltage stabilizing circuit, and the circuit adjusts the duty ratio D of the DC / DC converter through the PID control algorithm to adjust the load voltage V o . When the voltage across the capacitor C o is less than the conduction voltage V set of the relay coil, that is, when the load voltage V o is less than the conduction voltage V set of the relay coil, the relay switch S 2 closes, and the switches S 1 and S 3 are open, and the voltage stabilizing circuit does not work. At this time, the induced voltage V s of the receiving coil will directly charge C o until the voltage across C o rises to the conduction voltage V set of the relay coil. At this time, the switches S 1 and S 3 close, and the switch S 2 opens, and the DC / DC converter starts to work normally to supply power to the load. Since the output voltage V o has risen to a certain value, the DC / DC module can work normally in a stable range.

[0066] It should be understood that Figure 4Only one connection method of the three switches is given. Any switch connection method that can achieve the voltage stabilization method proposed in this application is within the protection scope of this application. For example: It is also possible to Figure 4 make corresponding symmetric connections to the three switches in

[0067] That is, the first switch is connected between the negative output of the rectifier circuit and the negative input of the DC / DC converter; the second switch is connected between the negative output of the rectifier circuit and the negative output of the DC / DC converter; the third switch is connected between the negative output of the DC / DC converter and the negative electrode of the device to be charged. This application does not limit the specific connection relationship.

[0068] Optionally, when Figure 4 the device to be charged in the voltage stabilization circuit is disconnected, Figure 4 the voltage values on both sides of C in in in are V o (i.e., an example of the input voltage of the first circuit). Among them, V in = V in * D / (1 - D). Therefore, it is possible to judge whether the output voltage V o reaches the set value by detecting V o or V o . Compared with detecting V in , the relay voltage is lower and the power consumption is smaller when detecting V in in the boost mode. However, after V o reaches the set value, it may take some time for V in to reach the set value. Therefore, there is a risk of entering the unstable interval. Therefore, it is necessary to set whether to detect V o or V in

[0069]

[0070] Refer to Figure 5 Figure 5 which is a schematic diagram of a single-switch wireless charging receiver device provided by this application.

[0071] ​The wireless charging receiving device includes: an induction circuit, a rectification circuit, a DC / DC converter, a third switch (S 3 ), a first capacitor (C o ) and a relay (i.e., an example of an intelligent selection module).

[0072] Among them, the induction circuit is used to provide voltage for the device to be charged; the rectification circuit is used to convert the alternating current generated by the induction circuit into direct current; the DC / DC converter is used to regulate the voltage of the device to be charged; the third switch is connected between the positive output of the DC / DC converter and the positive pole of the device to be charged; the first capacitor is used to charge the coil in the relay; the relay is used to control the closing or opening of the third switch through the conduction voltage of the coil in the relay.

[0073] Optionally, when the voltage V o across the first capacitor is less than the conduction voltage V set of the relay (i.e., an example of the first preset voltage value), the relay disconnects the third switch; or when the voltage V o across the first capacitor is greater than or equal to the conduction voltage V set of the relay, the relay closes the third switch.

[0074] Optionally, when the third switch of the voltage stabilization circuit in Figure 5 is turned on (i.e., the device to be charged is disconnected), Figure 5 the voltage value on both sides of C in in is V in (i.e., another example of the input voltage of the first circuit), then V o = V in * D / (1 - D). Therefore, it is also possible to judge whether the output voltage V in reaches the set value by detecting V o . Compared with detecting V o , the relay voltage is lower and the power consumption is smaller when detecting V in in the boost mode. However, after V in reaches the set value, it may take some time for V o to reach the set value. Therefore, there is a risk of entering an unstable range. Therefore, it is necessary to determine whether to detect V in or V o according to the specific circuit. This application does not make specific limitations on this. The third type: the two-switch method.

[0075] Referring to Figure 6 , Figure 6 is a schematic diagram of a two-switch wireless charging receiving device provided by this application.

[0076] The wireless charging receiving device includes: an induction circuit, a rectification circuit, a DC / DC converter, a third switch (S3), a fourth switch (S4), a first capacitor (C o ), a second capacitor (C in ), a first relay, and a second relay.

[0077] Among them, the induction circuit is used to provide voltage for the device to be charged; the rectification circuit is used to convert the alternating current generated by the induction circuit into direct current; the DC / DC converter is used to adjust the voltage of the device to be charged; the third switch is connected between the positive output of the DC / DC converter and the positive pole of the device to be charged; the fourth switch is connected between the negative output of the DC / DC converter and the negative pole of the device to be charged; the first capacitor is used to charge the coil in the first relay; the second capacitor is used to charge the coil in the second relay; the first relay is used to control the closing or opening of the third switch through the conduction voltage of the coil in the relay; the second relay is used to control the closing or opening of the fourth switch through the conduction voltage of the coil in the second relay.

[0078] Optionally, when the voltage V o across the first capacitor is less than the conduction voltage V set1 of the first relay (i.e., an example of the first preset voltage value), the first relay disconnects the third switch; or when the voltage V in across the second capacitor is less than the conduction voltage V set2 of the second relay (i.e., an example of the second preset voltage value), the second relay disconnects the fourth switch; or when the voltage V o across the first capacitor is greater than or equal to the conduction voltage V set1 of the first relay and the voltage V in across the second capacitor is greater than or equal to the conduction voltage V set2 of the second relay, the first relay closes the third switch and the second relay closes the fourth switch.

[0079] By way of example and not limitation, the DC / DC converter in all embodiments of the present application may be a Buck - Boost circuit.

[0080] It should be understood that the present application only exemplarily gives the specific circuit structure diagrams of three methods for implementing the voltage stabilization method proposed by the present application, and any circuit structure capable of implementing the voltage stabilization method of the present application falls within the protection scope of the present application.

[0081] In addition to the internal resistance of the coil on the receiving side affecting the function of the voltage stabilization circuit, different receiving - side induced voltages V s will also affect the unstable range of the voltage stabilization circuit.

[0082] SeeFigure 7 , Figure 7 is the variation relationship diagram between different Vs and D when V o = 5 is the target stable value. It can be seen that s in Figure 7 when R s , R o , and η are the same, taking V o = 5 as an example of the target stable value, when the induced voltage V s is equal to 5, 10, and 15 respectively, the larger V s is, the smaller the unstable interval represented by the shaded part is.

[0083] Since the coupling effect between the receiving coil and the transmitting coil affects the magnitude of its induced voltage V s , in view of this, the present application proposes a primary circuit structure that can better achieve the voltage stabilization function of the load circuit by selecting the transmitting coil with the best coupling with the receiving coil.

[0084] Figure 8 is a schematic diagram of a wireless charging transmitting device provided by the present application.

[0085] The wireless charging transmitting device includes a primary circuit power circuit, a switch group (for example: n (n≥2) gating switches S 1 ,…, S n ), and a transmitting coil array. Among them, the transmitting coil array includes n conducting transmitting coils TX 1 ,…, TX n , and the gating switches S 1 ,…, S n correspond to the conducting transmitting induction coils TX 1 ,…, TX n one by one. The power circuit, the switch group, and the induction coil array are connected in series according to Figure 7 .

[0086] Optionally, the device may further include a sampling circuit, a comparison circuit, and a peak holding circuit. Among them,

[0087] The power circuit is used to provide an excitation current for the transmitting induction coil array.

[0088] The high-frequency sampling circuit is used to perform periodic sampling on the currents on the n conducting transmitting coils.

[0089] The peak holding circuit is used to hold the peak current in the sinusoidal current sampled on the n conducting transmitting coils.

[0090] The comparison circuit is used to compare the currents on the n sampled coils to determine the minimum current on the n coils.

[0091] The intelligent switch gating module is used to determine the closing or opening of n switches in the switch group according to the minimum current on the n coils.

[0092] It should be understood that when the currents on the n coils are compared using a comparison circuit, the parameters of the currents must be the same, for example: comparing the peak currents or average currents on the n coils.

[0093] It should be noted that the n transmitting coils and the receiving coil on the receiving side have mutual inductance M 1 ,…,M n , under the condition that the power circuit outputs the same voltage, in the above current calculation process, it can be assumed that the self-inductance of the n conducting transmitting induction coils is exactly the same.

[0094] Optionally, the 1 ,…,t n Sequentially turn on switch S 1 ,…,S n The current i of each transmitting induction coil branch is obtained in turn through the microcontroller unit (MCU) 1 ,…,i n As mentioned above, it can be the peak current of n coils or the average current of n coils, which is not specifically limited in this application. Since the higher the coupling coefficient between the transmitting induction coil and the receiving coil, the smaller the current of the transmitting coil, the comparison circuit is based on the time t 1 ,…,t n The current in the n transmitting coils that are turned on determines the minimum current value i k The intelligent switch gating module closes the minimum current i according to the minimum current value k The corresponding switch S of the conducting coil k , turn on the remaining switches in the switch group, that is, TX k The coil is the best conduction coil.

[0095] Optionally, a relay can be used as an example of an intelligent switch gating module, and the relay includes a switch S 1 ,…,S n And a relay coil corresponding to each switch.

[0096] Optionally, the high-frequency sampling circuit uses LTC6252 with a bandwidth of 720MHz as a pre-stage sampling scaling circuit to ensure the sampling range while meeting the bandwidth requirement.

[0097] Optionally, the peak hold circuit uses OPA615 as a transconductance value peak sampling circuit, and its bandwidth of 720MHz can easily meet the requirements of high-frequency sampling.

[0098] The following takes the transmitting - side circuit including three switches S 1 、S 2 and S 3 、and the transmitting - coil array including three conducting transmitting coils TX_x, TX_y, TX_z as an example for illustration. Among them, the selected switches S 1 、S 2 and S 3 correspond to the conducting transmitting coils TX_x, TX_y, TX_z one by one respectively.

[0099] Refer to Figure 9 , Figure 9 which is a schematic diagram of a wireless - charging transmitting device with three transmitting coils provided by this application.

[0100] The three conducting transmitting coils TX_x, TX_y, TX_z are respectively located in the x, y, and z directions. When the receiving coil RX_x is in the x direction, the conducting transmitting coil TX_x in the x direction has the best coupling with the receiving coil RX_x. At this time, there are mutual inductances M xx , M yx and M zx among the three conducting transmitting coils and the receiving coil, where M xx >M yx , M xx >M zx . Then, under the condition of the same output voltage of the power circuit, by sequentially selecting the switches S 1 、S 2 and S 3 , by sampling the currents i 1 , i 2 , i 3 in each branch, where i 1 , i 2 , i 3 are respectively the peak currents passing through the transmitting coils TX_x, TX_y, TX_z. Since M xx >M yx , M xx >M zx , then i 1 <i 2 , i 1 <i 3 . According to the minimum current value, determine that TX_x is the best - conducting coil, and close the switch S 1 , and select the transmitting coil TX_x. At this time, the coupling between the transmitting coil TX_x and the receiving coil RX_x is the best, and the induced voltage of the receiving - side circuit is larger, and the unstable interval is relatively smaller.

[0101] It should be understood that Figure 9Among them, LTX_x, LTX_y, and LTX_z respectively represent the self-inductances of the three transmitting coils in the x, y, and z directions. In the above calculation process of the current, it can be considered that the self-inductances of the three receiving coils are exactly the same.

[0102] In the above technical solution, the transmitting coils in the transmitting coil array are sequentially selected, and the optimal conducting coil on the transmitting side is determined and selected by the magnitude of the peak current of each transmitting coil branch, so that its coupling effect with the receiving coil is the best, the induced voltage of the receiving coil is the highest, and in this solution, only the transmitting side circuit needs to judge the magnitude of the current, without communication between the transmitting side circuit and the receiving side circuit.

[0103] In addition, the present application also proposes a method for determining the transmitting induction coil of the primary circuit. By sequentially collecting the magnitudes of the currents on each coil in the coil array at different times, the coil with the smallest current is selected as the actual transmitting coil. The specific method is the same as that in Figure 8 、 Figure 9 and will not be elaborated here.

[0104] As can be seen from the above, the significantly increased AC internal resistance R of the receiving side induction coil s will cause the traditional voltage stabilizing circuit to have an unstable interval where the voltage stabilizing function fails. Therefore, the present application improves the existing induction coil and can reduce the AC internal resistance of the receiving side induction coil.

[0105] According to the finite element simulation results of the planar spiral coil, the magnetic field distribution of the planar spiral coil shows that the magnetic field intensity is larger on the inner and outer sides and smaller in the middle. To reduce the AC resistance of the coil, it is necessary to design a smaller wire diameter of the winding at the place where the field intensity is larger, which can reduce the eddy current loss.

[0106] See Figure 10 , Figure 10 A design scheme of a planar spiral coil proposed by the present application. The induction coil is composed of a combination of multiple turns of coils. The inner diameter (ID), outer diameter (OD), and cross-section of the coil are as shown in Figure 10 For the design of the coupling coil, a suitable position in the middle of the induction coil is selected as the position of the turn with the maximum line width, and the turn width of each turn first increases in proportion of k1 from the inside to the outside, and then decreases in proportion of k2, while the gap between each turn first changes in proportion of kg1 from the inside to the outside, and then changes in proportion of kg2, where k1>1, k2>1, kg1≥1, kg2≥1.

[0107] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present application. It should be understood that the above description is only for the specific embodiments of the present application and is not intended to limit the protection scope of the present application. Any modifications, equivalent replacements, improvements, etc. made on the basis of the technical solutions of the present application shall be included within the protection scope of the present application.

Claims

1. A method for regulated output, characterized in that, comprising: judging whether the output voltage of the first circuit in the wireless charging receiving circuit is higher than or equal to a first preset voltage value, wherein the output voltage is used to charge the device to be charged, the first circuit includes a DC / DC converter, a first switch, a second switch, a third switch and a first capacitor, wherein the DC / DC converter is used to regulate the voltage of the device to be charged, the input negative electrode of the DC / DC converter is connected to the output negative electrode of the rectifier circuit, and the output negative electrode of the DC / DC converter is connected to the negative electrode of the device to be charged, the first switch, the first switch is connected between the output positive electrode of the rectifier circuit and the input positive electrode of the DC / DC converter, the second switch, the second switch is connected between the output positive electrode of the rectifier circuit and the output positive electrode of the DC / DC converter, the third switch, the third switch is connected between the output positive electrode of the DC / DC converter and the positive electrode of the device to be charged, the first capacitor, the first capacitor is connected between the second switch and the output negative electrode of the DC / DC converter, and the output voltage of the first circuit is equal to the voltage across the first capacitor; when the output voltage of the first circuit is higher than or equal to the first preset voltage value, connecting the device to be charged to the first circuit; when the output voltage of the first circuit is lower than the first preset voltage value, disconnecting the device to be charged from the first circuit.

2. The method according to claim 1, characterized in that, when the output voltage of the first circuit is higher than or equal to the first preset voltage value, connecting the device to be charged to the first circuit, including: when the output voltage of the first circuit is higher than or equal to the first preset voltage value and the input voltage of the first circuit is higher than or equal to a second preset voltage value, connecting the device to be charged to the first circuit, wherein the input voltage is used to provide voltage for the output voltage.

3. The method according to claim 1, characterized in that, when the output voltage of the first circuit is higher than or equal to the first preset voltage value, connecting the device to be charged to the first circuit, including: when the input voltage of the first circuit is higher than or equal to the second preset voltage value, connecting the device to be charged to the first circuit, wherein, the input voltage is used to provide voltage for the output voltage, and when the input voltage of the first circuit is higher than or equal to the second preset voltage value, the output voltage of the first circuit is higher than or equal to the first preset voltage value.

4. The method according to any one of claims 1 to 3, characterized in that, the method further includes: when the output voltages of the power circuits in the wireless charging transmitting circuit are the same, closing N switches in the switch group of the wireless charging transmitting circuit in sequence at N moments, and simultaneously turning on the remaining (N - 1) switches, where N ≥ 2 and N is an integer, wherein, the wireless charging transmitting circuit includes: the switch group; An induction coil array, the induction coil array includes N coils, and the N switches respectively correspond to the N coils one by one; The power circuit, the power circuit is used to provide an excitation current for the coil array; The power circuit, each of the N switches and the coil corresponding to each switch are connected in series; Sample the currents on the N coils after the N switches are sequentially closed; Close the switch corresponding to the minimum current value on the N coils, and at the same time disconnect the remaining (N - 1) switches.

5. A wireless charging device, Characterized in that, Comprising: A wireless charging receiving circuit, the wireless charging receiving circuit includes: An induction circuit, the induction circuit is used to provide a voltage for the device to be charged; A rectification circuit, the rectification circuit is used to convert the alternating current generated by the induction circuit into direct current; A first circuit, the first circuit includes a DC / DC converter, a first switch, a second switch, a third switch and a first capacitor, wherein, The DC / DC converter is used to adjust the voltage of the device to be charged, the input negative electrode of the DC / DC converter is connected to the output negative electrode of the rectification circuit, and the output negative electrode of the DC / DC converter is connected to the negative electrode of the device to be charged; The first switch is connected between the output positive electrode of the rectification circuit and the input positive electrode of the DC / DC converter; The second switch is connected between the output positive electrode of the rectification circuit and the output positive electrode of the DC / DC converter; The third switch is connected between the output positive electrode of the DC / DC converter and the positive electrode of the device to be charged; The first capacitor is connected between the second switch and the output negative electrode of the DC / DC converter; Wherein, when the voltage across the first capacitor is less than the first preset voltage value, the second switch is in the closed state and the first switch and the third switch are in the open state, When the voltage across the first capacitor is greater than or equal to the first preset voltage value, the second switch is in the open state and the first switch and the third switch are in the closed state.

6. The wireless charging device according to claim 5, Characterized in that, The wireless charging receiving circuit further includes: An intelligent switch selection module, the intelligent switch selection module controls the closing or opening of the first switch, the second switch and the third switch based on the voltage across the first capacitor.

7. The wireless charging device according to claim 6, Characterized in that, The intelligent switch selection module is a relay, the relay includes a coil, the first switch, the second switch and the third switch, and the first capacitor is used to charge the coil, When the conduction voltage of the coil is reached, the second switch is in the open state and the first switch and the third switch are in the closed state, otherwise, the second switch is in the closed state and the first switch and the third switch are in the open state, and the conduction voltage of the coil is the first preset voltage value.

8. The wireless charging device according to claim 5 or 6, Characterized in that, The wireless charging device further includes: A second capacitor, which is connected between the output positive electrode and the output negative electrode of the rectification circuit, where When the second switch is in the closed state and the first switch and the third switch are in the open state, the voltage V across the first capacitor o satisfies the following formula: V o = V in * D / (1 - D) wherein, the V in is the voltage across the second capacitor, and the D is the duty cycle of the DC / DC converter.

9. The wireless charging device according to any one of claims 5 to 7, characterized in that The wireless charging device further includes: A wireless charging transmitting circuit, the wireless charging transmitting circuit includes: a switch group, the switch group includes N switches, where N≥2 and N is an integer; An induction coil array, the induction coil array includes N coils, and the N switches respectively correspond to the N coils one by one; A power circuit, the power circuit is used to provide an excitation current for the induction coil array; The power circuit, each of the N switches and the coil corresponding to each switch are connected in series, wherein, when the coupling coefficient between the coil corresponding to the fifth switch among the N switches and the receiving coil in the wireless charging receiving circuit is the highest, the fifth switch is in a connected state, and the remaining (N - 1) switches among the N switches are in a disconnected state.

10. The wireless charging device according to claim 9, characterized in that The wireless charging transmitting circuit further includes: A sampling circuit, the sampling circuit is used to perform periodic sampling on the currents on the N coils; A comparison circuit, the comparison circuit is used to compare the sampled currents on the N coils to determine the minimum current on the N coils; An intelligent switch gating module, the intelligent switch gating module is used to determine the closing or opening of the N switches according to the minimum current on the N coils.

11. The wireless charging device according to claim 10, characterized in that The intelligent switch gating module is a relay, and the relay includes the N switches in the switch group.

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