A wireless charging method and system without additional communication module

Abstract

The present invention belongs to the field of wireless charging technology, and provides a wireless charging method without an additional communication module, including the steps of: S1, the transmitter and the receiver respectively control their respective circuits; S2, modulate the rectifier bridge of the receiver; S3, the transmitter detects the signal change caused by the modulation of the rectifier bridge of the receiver, obtains the signal sent by the receiver, and regulates the circuit of the transmitter. The advantage of the present invention is that the transmitter and the receiver can be coordinated and controlled without the need to use an additional communication module for wireless charging, can achieve constant voltage or constant current output, and can find the best charging working point.

Description

Technical Field

[0001] The present invention relates to the field of wireless charging technology, and in particular to a wireless charging method and system without an additional communication module. Background Art

[0002] Wireless charging refers to the technology of transferring electric energy between the charger and the device being charged through electromagnetic induction and other technologies, thereby charging the battery of the device being charged. Compared with wired charging, wireless charging has the advantages of less leakage, fully automatic operation and unattended operation, and has been widely used in various fields.

[0003] At present, in wireless charging technology, it is often necessary for the charger and the charged device to communicate and identify each other in order to match each other and then charge. When the charging speed needs to be adjusted, an adjustment signal needs to be sent through a special communication module, which will reduce the charging efficiency. Summary of the invention

[0004] The object of the present invention is to provide a wireless charging method and system without an additional communication module, so as to solve the problem that the charger and the charged device need complicated communication connection in wireless charging;

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A wireless charging method without an additional communication module comprises the following steps:

[0007] S1, the transmitting end and the receiving end control their respective circuits;

[0008] S2, modulate the rectifier bridge at the receiving end;

[0009] S3. The transmitter detects the signal change caused by the modulation of the rectifier bridge at the receiver, obtains the signal sent by the receiver, and regulates the circuit at the transmitter.

[0010] Furthermore, the specific steps of regulating the circuit of the transmitting end in step S3 are:

[0011] S31, the transmitting end adjusts the coil current of the transmitting end according to the signal sent by the receiving end to find a stable working point;

[0012] S32, the transmitting end finds the optimal working point by gradually changing the working point position near the stable working point.

[0013] Further, step S31 includes:

[0014] S311, the receiving end adjusts the phase shift angle of the receiving end rectifier bridge through the PI control method;

[0015] S312, determining whether the phase shift angle adjustment of the rectifier bridge at the receiving end meets the charging requirements;

[0016] S313: If yes, then find a stable operating point and obtain the threshold current of the DC side of the transmitter when the charging requirement of the receiver is met.

[0017] Furthermore, when the phase shift angle of the rectifier bridge at the receiving end is the largest and cannot meet the control requirements of the receiving end, the steps to meet the control requirements of the receiving end are:

[0018] A1. The receiving end controller controls the receiving end rectifier bridge to conduct in a preset manner;

[0019] A2, by changing the conduction mode of the rectifier bridge at the receiving end, the receiving end coil is short-circuited, and a short-circuit signal is sent to the transmitting end, so that the input current on the DC side of the transmitting end is reduced;

[0020] A3. After the transmitter controller detects that the DC input current of the transmitter is reduced, the transmitter controller gradually increases the phase shift angle of the inverter in the transmitter according to the short-circuit signal until the short circuit no longer occurs at the receiving end, and returns to step S311.

[0021] Further, step S32 includes:

[0022] S321, the receiving end monitors the charging current or charging voltage in real time, and when no short-circuit signal is detected, adjusts the phase shift angle of the rectifier bridge at the receiving end to meet the charging requirement;

[0023] S322, the transmitter monitors the DC side input current in real time, and controls the phase shift angle of the inverter in the transmitter through the transmitter controller to obtain the optimal working point.

[0024] Further, step S321 includes:

[0025] S3211, the receiving end monitors the charging current or charging voltage in real time;

[0026] S3212: When no short-circuit signal is detected, the receiving end adjusts the phase shift angle of the receiving end rectifier bridge through a PI controller to meet the charging requirement.

[0027] Further, step S322 includes:

[0028] S3221, detecting the DC input current of the transmitting end;

[0029] S3222, determining whether the input current is greater than a threshold current;

[0030] S3223. If so, the transmitting end controller controls the phase shift angle of the transmitting end inverter to increase with a first preset step size, and returns to step S3221; if not, the transmitting end controller perturbs the inverter bridge phase shift angle with a second preset step size to change the input current in a decreasing direction, thereby obtaining the optimal operating point.

[0031] The present invention also provides a wireless charging system without an additional communication module, comprising a transmitting end and a receiving end;

[0032] The transmitting end includes a DC power supply, a transmitting end controller, a transmitting end inverter and a transmitting end coil, and the transmitting end controller controls the transmitting end inverter to transmit the electric energy of the DC power supply to the receiving end through the transmitting end coil;

[0033] The receiving end includes a receiving end controller, a receiving end coil, a receiving end rectifier bridge, a receiving end filter capacitor and a battery load. The receiving end controller controls the receiving end rectifier bridge so that the electric energy obtained by the receiving end coil is transmitted to the battery load after passing through the filter capacitor.

[0034] The receiving end rectifier bridge comprises two bridge arms, wherein a comparator and a sampling resistor are connected in series between one of the bridge arms and the receiving end controller, and the comparator and the sampling resistor are used to determine the current zero-crossing point.

[0035] Compared with the prior art, the present invention has at least the following beneficial effects:

[0036] The present invention detects the signal changes caused by the modulation of the rectifier circuit at the receiving end through the transmitting end, obtains the signal sent by the receiving end, and regulates the circuit of the transmitting end, so that the transmitting end and the receiving end can be coordinated and controlled without using an additional communication module for wireless charging, and can achieve constant voltage or constant current output and find the optimal charging operating point. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is an overall flow chart of the wireless charging method in Embodiment 1 of the present invention;

[0038] Figure 2 is a flowchart of step S3 in embodiment 1 of the present invention;

[0039] Figure 3 is a flowchart of step S31 in the first embodiment of the present invention;

[0040] Figure 4 is a flowchart of steps in the first embodiment of the present invention to meet the control requirements of the receiving end;

[0041] Figure 5 is a flowchart of step S32 in the first embodiment of the present invention;

[0042] Figure 6is a flowchart of step S321 in the first embodiment of the present invention;

[0043] Figure 7 is a flowchart of step S322 in the first embodiment of the present invention;

[0044] Figure 8 This is a circuit topology diagram of the wireless charging system in the second embodiment of the present invention;

[0045] Fig. 9 yes Figure 8 A simplified circuit model diagram of the circuit topology;

[0046] Fig.10 is a schematic diagram of the principle of a wireless charging system in Embodiment 2 of the present invention;

[0047] Fig.11 is a schematic diagram of the structure of the receiving end rectifier bridge in the second embodiment of the present invention;

[0048] Fig.12 It is a schematic diagram of the input voltage and current of the receiving end rectifier bridge and the switch tube driving waveform in the second embodiment of the present invention. DETAILED DESCRIPTION

[0049] It should be noted that in the present invention, descriptions such as "first", "second", "one", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0050] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0051] The following are specific embodiments of the present invention, and the technical solutions of the present invention are further described in conjunction with the accompanying drawings, but the present invention is not limited to these embodiments.

[0052] Embodiment 1

[0053] like Figure 1 As shown, the present invention provides a wireless charging method without an additional communication module, comprising the steps of:

[0054] S1, the transmitting end and the receiving end control their respective circuits;

[0055] S2, modulate the rectifier bridge at the receiving end;

[0056] S3. The transmitter detects the signal change caused by the modulation of the rectifier bridge at the receiver, obtains the signal sent by the receiver, and regulates the circuit at the transmitter.

[0057] like Figure 2 As shown, the specific steps of regulating the circuit of the transmitting end in step S3 are:

[0058] S31, the transmitting end adjusts the coil current of the transmitting end according to the signal sent by the receiving end to find a stable working point;

[0059] S32, the transmitting end finds the optimal working point by gradually changing the working point position near the stable working point.

[0060] like Figure 3 As shown, step S31 includes:

[0061] S311, the receiving end adjusts the phase shift angle of the receiving end rectifier bridge through the PI control method;

[0062] S312, determining whether the phase shift angle adjustment of the rectifier bridge at the receiving end meets the charging requirements;

[0063] S313: If yes, then find a stable operating point and obtain the threshold current of the DC side of the transmitter when the charging requirement of the receiver is met.

[0064] Further, such as Figure 4 As shown, when the phase shift angle of the receiving end rectifier bridge is the largest and cannot meet the control requirements of the receiving end, the steps to meet the control requirements of the receiving end are:

[0065] A1. The receiving end controller controls the receiving end rectifier bridge to conduct in a preset manner;

[0066] A2, by changing the conduction mode of the rectifier bridge at the receiving end, the receiving end coil is short-circuited, and a short-circuit signal is sent to the transmitting end, so that the input current on the DC side of the transmitting end is reduced;

[0067] A3. After the transmitter controller detects that the DC input current of the transmitter is reduced, the transmitter controller gradually increases the phase shift angle of the inverter in the transmitter according to the short-circuit signal until the short circuit no longer occurs at the receiving end, and returns to step S311.

[0068] like Figure 5 As shown, step S32 includes:

[0069] S321, the receiving end monitors the charging current or charging voltage in real time, and when no short-circuit signal is detected, adjusts the phase shift angle of the rectifier bridge at the receiving end to meet the charging requirement;

[0070] S322, the transmitter monitors the DC side input current in real time, and controls the phase shift angle of the inverter in the transmitter through the transmitter controller to obtain the optimal working point.

[0071] like Figure 6 As shown, step S321 includes:

[0072] S3211, the receiving end monitors the charging current or charging voltage in real time;

[0073] S3212: When no short-circuit signal is detected, the receiving end adjusts the phase shift angle of the receiving end rectifier bridge through PI control to meet the charging requirements.

[0074] like Figure 7 As shown, step S322 includes:

[0075] S3221, detecting the DC input current of the transmitting end;

[0076] S3222, determining whether the input current is greater than a threshold current;

[0077] S3223. If so, the transmitting end controller controls the phase shift angle of the transmitting end inverter to increase with a first preset step size, and returns to step S3221; if not, the transmitting end controller perturbs the inverter bridge phase shift angle with a second preset step size to change the input current in a decreasing direction, thereby obtaining the optimal operating point.

[0078] The present invention detects the signal changes caused by the modulation of the rectifier circuit at the receiving end through the transmitting end, obtains the signal sent by the receiving end, and regulates the circuit of the transmitting end, so that the transmitting end and the receiving end can be coordinated and controlled without using an additional communication module for wireless charging, and can achieve constant voltage or constant current output and find the optimal charging operating point.

[0079] Embodiment 2

[0080] The present invention provides a wireless charging system that does not require an additional communication module, and the circuit topology it relies on is as follows Figure 8 shown.

[0081] Specifically, the simplified circuit model is as follows: Fig. 9 As shown, according to Fig. 9 The simplified circuit model shown has the following basic circuit equation:

[0082] (R1+jX1)I1+jωM 12 I2=V1 (1)

[0083] jωM 12 I1+(R2+R L +jX2)I2=0 (2)

[0084] Where Ri , i = 1 or 2 is the parasitic resistance in the circuit, generally including the resistance of the coil and the equivalent series resistance of the capacitor; X i =ωL i -1 / (ωC i ), i = 1 or 2 is the reactance of resonator i; I1 and I2 are the current phasors of the transmitting and receiving loops respectively; V1 is the phasor of the input voltage; M 12 is the mutual inductance of the two coils; R L is the equivalent load resistance; ω=2πf is the angular frequency (f is the frequency of the power supply).

[0085] According to the theory of wireless power transmission, X i = 0 (that is, full compensation) can obtain the highest power transmission efficiency and the minimum input apparent power (that is, the input voltage and input current are in phase).

[0086] At this time, the efficiency of the system is

[0087]

[0088] The system efficiency is proportional to R L Derivative, get the equivalent optimal load resistance of the system

[0089]

[0090] Where M is the mutual inductance of the coil.

[0091] When both the transmitting inverter and the receiving rectifier bridge adopt phase shift control

[0092]

[0093]

[0094] Among them, U1 is the inverter input voltage, U in is the DC side input voltage, α is the inverter phase shift angle, U2 is the rectifier bridge output voltage, U out is the battery voltage, and β is the phase shift angle of the rectifier bridge.

[0095] Ignore the rectifier bridge loss

[0096] U2I2=U out I out (7)

[0097] U out ,I out is the charging voltage and the charging current, so the charging current I out for

[0098]

[0099] Equivalent load resistance

[0100]

[0101] According to (1), (2) and the full compensation condition

[0102]

[0103] Substituting (5) and (9) into (10), we can obtain

[0104]

[0105] Efficiency when converter losses are ignored

[0106]

[0107] Minimum DC input current

[0108]

[0109] Therefore, the system equivalent load resistance can be made equal to the optimal load resistance by adjusting the phase shift angle β at the receiving end, that is,

[0110]

[0111] This system can achieve the best efficiency. By changing the phase shift angle α of the transmitter inverter, the receiver controller can change the phase shift angle β of the receiver accordingly to maintain a constant current or voltage. When the phase shift angle of the receiver reaches the optimal value, it is equivalent to I dc The minimum value is reached, so I can be found by monitoring the DC input current of the transmitter. dc Minimum value to improve system efficiency.

[0112] The wireless charging system of the present invention comprises a transmitter and a receiver, wherein the transmitter comprises a DC power supply, a transmitter controller, a transmitter inverter and a transmitter coil, and the transmitter controller controls the transmitter inverter to transmit the electric energy of the DC power supply to the receiver through the transmitter coil.

[0113] The receiving end includes a receiving end controller, a receiving end coil, a receiving end rectifier bridge, a receiving end filter capacitor and a battery load. The receiving end controller controls the receiving end rectifier bridge so that the electric energy obtained by the receiving end coil is transmitted to the battery load after passing through the filter capacitor.

[0114] The principle block diagram of this system is as follows Fig.10 As shown, first, the receiving end monitors the charging current or charging voltage in real time, and when no short-circuit signal is detected, the receiving end controller controls the phase shift angle of the receiving end rectifier circuit to meet the charging requirements;

[0115] However, when the phase shift angle of the rectifier bridge at the receiving end is 180° and still cannot meet the output current or output voltage control requirements, the receiving end controller determines that the power provided by the transmitting end is insufficient. Subsequently, the receiving end controller controls the rectifier bridge switch to short-circuit the coil.

[0116] Specifically, the receiving end controller controls the two upper tubes or the two lower tubes of the rectifier bridge to be turned on at the same time, entering the coil short-circuit state. The time that the receiving end is in the coil short-circuit state is determined by the operating frequency of the system, and corresponding adjustments are made according to different working cycles. After exiting the coil short-circuit state, the receiving end rectifier bridge starts to adjust from a phase shift angle of 180°. If it still cannot meet the control requirements, it enters the next coil short-circuit state and continues to transmit the short-circuit signal to the primary side.

[0117] When the system is in normal output state, the transmitting coil current is

[0118]

[0119] When the system is in the coil short-circuit state, the transmitting coil current is

[0120]

[0121] When the coil is in a short-circuit state, the transmitting coil current is less than the transmitting coil current in the normal output state.

[0122]

[0123] Therefore, during the coil short-circuit state, the DC input current of the system will drop significantly. Therefore, it is possible to determine whether the system has entered the coil short-circuit state by monitoring the changes in the DC input current.

[0124] In this system, a threshold current I is set th , the DC side input current is less than I th When , the system is judged to have entered the coil short-circuit state, and the transmitter controller changes the inverter phase shift angle α accordingly until the system control requirements are met.

[0125] The selection of the threshold current needs to satisfy the requirement of being able to distinguish between state A and state B. From (5) and (16), we can get

[0126]

[0127] The maximum DC input current in state B is

[0128]

[0129] According to the relationship between input power and output power

[0130] Iin_modeA_dc U in =P in >P out (20)

[0131] The minimum DC input current in state A is

[0132]

[0133] Therefore, the threshold current I th The selection should satisfy

[0134] I in_modeB_max <I th <I in_modeA_min (twenty two)

[0135] After detecting that the receiving end coil is approaching, the transmitting end enters the continuous mode, and the phase shift angle of the transmitting end inverter gradually increases from 0°. The receiving end transmits a short-circuit signal to the transmitting end to reflect the power status. When the short-circuit signal sent by the receiving end is not detected for a period of time, the phase shift angle of the transmitting end inverter no longer increases, and the system enters the continuous charging mode.

[0136] In the continuous charging mode, the receiving end adjusts the phase shift angle of the rectifier bridge through the PI controller to control the constant current output, and the transmitting end monitors the DC side input current. The DC side input current is less than the threshold current I th When , the transmitter controller controls the inverter phase shift angle to increase with a step size of α1 to increase the output power.

[0137] When the DC input current is greater than I th When , the transmitter controller disturbs the inverter bridge phase shift angle with a step size of α2, so that the DC side input current changes in the direction of reduction to improve the system efficiency.

[0138] Furthermore, the system uses MOS tubes instead of diodes in the receiving end rectifier bridge, and the receiving end rectifier bridge part is characterized by: one bridge arm works in synchronous rectification mode, and one bridge arm works in phase shift mode. At the same time, in order to ensure that the leading arm works in synchronous rectification mode, the system connects a comparator and a sampling resistor in series between the leading arm and the receiving end controller to determine the current zero crossing point. After the current passes zero, the comparator sends an interrupt signal to the receiving end controller, and the receiving end controller can output the corresponding rectifier bridge PWM waveform.

[0139] The specific working mode of the rectifier part is as follows Fig.11 As shown, the leading arm switches S5 and S6 work in synchronous rectification mode, turning on and off as the current passes through zero, and the lagging arm switches S7 and S8 work in phase shift mode, adjusting the working state through the phase shift angle provided by the receiving end controller to meet the control requirements. The specific switch tube drive waveform is shown in Fig.12 shown.

[0140] The system detects the signal changes caused by the modulation of the receiving end rectifier circuit through the transmitter, obtains the signal sent by the receiver, and regulates the circuit of the transmitter, so that the transmitter and the receiver can be coordinated and controlled without the need to use an additional communication module for wireless charging.

[0141] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A wireless charging method without an additional communication module, characterized in that: Includes steps: S1, the transmitting end and the receiving end control their respective circuits; S2, modulate the rectifier bridge at the receiving end; S3, the transmitter obtains the signal sent by the receiver by detecting the signal change caused by the modulation of the rectifier bridge at the receiver, and regulates the circuit of the transmitter; The specific steps of regulating the circuit of the transmitting end in step S3 are: S31, the transmitting end adjusts the coil current of the transmitting end according to the signal sent by the receiving end to find a stable working point; S32, the transmitting end finds the best working point by gradually changing the working point position near the stable working point; Step S31 includes: S311, the receiving end adjusts the phase shift angle of the receiving end rectifier bridge through the PI control method; S312, determining whether the phase shift angle adjustment of the rectifier bridge at the receiving end meets the charging requirements; S313: If yes, then find a stable operating point and obtain a threshold current on the DC side of the transmitter that meets the charging requirements of the receiver; When the phase shift angle of the receiving end rectifier bridge is the largest and cannot meet the control requirements of the receiving end, the steps to meet the control requirements of the receiving end are: A1. The receiving end controller controls the receiving end rectifier bridge to conduct in a preset manner; A2, by changing the conduction mode of the rectifier bridge at the receiving end, the receiving end coil is short-circuited, and a short-circuit signal is sent to the transmitting end, so that the input current on the DC side of the transmitting end is reduced; A3. After the transmitter controller detects that the DC input current of the transmitter is reduced, the transmitter controller gradually increases the phase shift angle of the inverter in the transmitter according to the short-circuit signal until the short circuit no longer occurs at the receiving end, and returns to step S311.

2. A wireless charging method without an additional communication module according to claim 1, characterized in that: Step S32 includes: S321, the receiving end monitors the charging current or charging voltage in real time, and when no short-circuit signal is detected, adjusts the phase shift angle of the rectifier bridge at the receiving end to meet the charging requirement; S322, the transmitter monitors the DC side input current in real time, and controls the phase shift angle of the inverter in the transmitter through the transmitter controller to obtain the optimal working point.

3. A wireless charging method without an additional communication module according to claim 2, characterized in that: Step S321 includes: S3211, the receiving end monitors the charging current or charging voltage in real time; S3212: When no short-circuit signal is detected, the receiving end adjusts the phase shift angle of the receiving end rectifier bridge through PI control to meet the charging requirements.

4. A wireless charging method without an additional communication module according to claim 2, characterized in that: Step S322 includes: S3221, detecting the DC input current of the transmitting end; S3222, determining whether the input current is greater than a threshold current; S3223. If so, the transmitting end controller controls the phase shift angle of the transmitting end inverter to increase with a first preset step size, and returns to step S3221; if not, the transmitting end controller perturbs the inverter bridge phase shift angle with a second preset step size to change the input current in a decreasing direction, thereby obtaining the optimal operating point.

5. A wireless charging system without an additional communication module, based on the wireless charging method without an additional communication module as claimed in any one of claims 1 to 4, characterized in that: Includes a transmitter and a receiver; The transmitting end includes a DC power supply, a transmitting end controller, a transmitting end inverter and a transmitting end coil, and the transmitting end controller controls the transmitting end inverter to transmit the electric energy of the DC power supply to the receiving end through the transmitting end coil; The receiving end includes a receiving end controller, a receiving end coil, a receiving end rectifier bridge, a receiving end filter capacitor and a battery load. The receiving end controller controls the receiving end rectifier bridge so that the electric energy obtained by the receiving end coil is transmitted to the battery load after passing through the filter capacitor. The receiving end rectifier bridge comprises two bridge arms, wherein an operational amplifier, a comparator and a sampling resistor are arranged between one of the bridge arms and the receiving end controller, and the operational amplifier, comparator and sampling resistor are used to determine the current zero-crossing point.

Images