Industrial-grade wireless charging system and control method

Abstract

The invention discloses an industrial-grade wireless charging system which is simple in structure, reduces product cost and matching complexity and can meet output requirements of different powers within a specified range. The circuit comprises a PFC which is used for converting alternating current into direct current voltage and outputting the direct current voltage; a DC / DC converter which reduces the PFC output DC voltage to a low voltage required by the system; the inverter is used for converting the direct current into alternating current with set frequency according to system requirements; a primary side compensation network; the coupling mechanism comprises a primary side coil and a secondary side coil, and the primary side coil and the secondary side coil are independent coils formed by winding Litz wires; a secondary side compensation network; and the rectifier is used for rectifying the alternating current induced by the secondary side into direct current and charging a battery of the equipment. The invention further discloses a control method of the industrial-grade wireless charging system.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless charging, and in particular to an industrial-grade wireless charging system. The present invention also provides a control method for the industrial-grade wireless charging system. Background Art

[0002] The currently released wireless charging standards for electric vehicles have specified parameters such as wireless charging topology (LCC-LCC), power levels (3kW, 7kW, 11kW), and offset range, and the industry is also in a rapid development stage.

[0003] However, in industrial-grade wireless charging technology, its application scenarios are diverse, including warehousing and logistics, power inspection, coal mining industry, service industry, etc., and its corresponding equipment is of various types, including AGV / AMR, inspection robots, special robots, industrial robots, etc., making it difficult to form standardized industry standards. In addition, the battery capacity of industrial-grade wireless charging equipment is generally low, so it does not require too much charging power. Common power levels are 60W, 120W, 300W, 600W, 1200, 3000W, and 7000W. How to set up a stable and reliable industrial-grade wireless charging system is a technical problem that urgently needs to be solved in the field of wireless charging. Summary of the invention

[0004] In view of the above problems, the present invention provides an industrial-grade wireless charging system, which has a simple structure, reduces product cost and matching complexity, and can adapt to different power output requirements within a specified range.

[0005] An industrial-grade wireless charging system, characterized in that it comprises:

[0006] PFC, which is used to convert AC power into DC voltage output;

[0007] A DC / DC converter, which converts the PFC output DC voltage into a low voltage required by the system;

[0008] Inverter, which converts DC power into AC power of a set frequency according to system requirements;

[0009] Primary side compensation network;

[0010] A coupling mechanism, comprising a primary coil and a secondary coil, wherein the primary coil and the secondary coil are independent coils wound by Litz wire;

[0011] Secondary side compensation network;

[0012] and a rectifier for rectifying the alternating current induced on the secondary side into direct current and charging the battery of the device;

[0013] The DC / DC converter is a Buck circuit;

[0014] The primary compensation network is composed of two groups of capacitors C1_a and C1_b, which are symmetrically distributed relative to the primary coil L1, and the secondary compensation network is composed of two groups of capacitors C2_a and C2_b, which are symmetrically distributed relative to the secondary coil L2;

[0015] The PFC, DC / DC converter, inverter, primary compensation network, and primary coil are combined to form a primary side, and the secondary coil, secondary compensation network, and rectifier are combined to form a secondary side;

[0016] The input end of the PFC is connected to a single-phase AC power grid, the output end of the PFC is connected to the input end of the DC / DC converter, the output end of the DC / DC converter is connected to an inverter, the two groups of corresponding capacitors of the primary compensation network are connected to the inverter arrangement, the coupling mechanism and the primary compensation network and the secondary compensation network form a series resonant topology, the two groups of capacitors of the secondary compensation network are connected to the rectifier arrangement, and the output end of the rectifier is connected to a battery.

[0017] It is further characterized by:

[0018] The inverter is a full-bridge inverter, which includes four MOS tubes, namely S1, S2, S3, and S4. The controlled parameters of the full-bridge inverter include the inverter bridge arm midpoint voltage UAB and the inverter current Iinv.

[0019] The full-bridge inverter realizes the change of the inverter operating frequency by controlling the driving frequency of the four MOS tubes S1, S2, S3, and S4, and the operating frequency range is MkHz to NkHz;

[0020] In the working range, the inverter load is weakly inductive, and the inverter bridge arm midpoint voltage UAB is always ahead of the inverter current Iinv in phase;

[0021] The inverter adopts phase shift control, and phase shift voltage regulation can be used as an auxiliary voltage regulation method;

[0022] The rectifier is composed of four MOS tubes forming a full-bridge structure. The four MOS tubes are Q1, Q2, Q3, and Q4. The four MOS tubes are used for synchronous rectification control. The parameters include the rectifier input current i in , rectifier bridge arm midpoint voltage Uab, rectifier output current i out ;

[0023] The rectifier input current i in It is generated by the induction of the secondary coil, and its frequency is consistent with the inverter frequency on the primary side. When the inverter on the primary side performs frequency conversion control, the rectifier input current i inAs it changes, the rectifier has a frequency tracking function and adjusts the synchronous rectification working frequency accordingly, that is, changes the drive control frequency of Q1, Q2, Q3, and Q4;

[0024] Among the driving waveforms of Q1, Q2, Q3, and Q4, the driving waveforms of Q1 and Q4 are in phase, the driving waveforms of Q2 and Q3 are in phase, the phase difference between Q1 and Q2 is 180 degrees, and the phase difference between Q3 and Q4 is 180 degrees;

[0025] The rectifier has the function of tracking the primary frequency, which is implemented by: a detecting the frequency of the induced voltage of the secondary coil; b detecting the frequency of the induced current of the secondary coil; c detecting the frequency of the voltage across the capacitor C2_a or C2_b; d detecting the frequency of the rectifier bridge arm midpoint voltage Uab; the above four methods realize the function of the secondary rectifier tracking the primary frequency, and one is selected or used in combination;

[0026] The rectifier bridge arm midpoint voltage Uab is clamped by the rechargeable battery voltage, and the platform voltage is equal to the rechargeable battery voltage;

[0027] The primary coil and primary compensation network, the secondary coil and secondary compensation network all form a series resonant topology with a constant current output characteristic. The secondary output current can be expressed as Expression; where I2 is the secondary coil current; UAB is the primary inverter bridge arm midpoint voltage; ω is the system operating angular frequency, and the frequency relationship is ω=2πf; M is the mutual inductance between the primary coil and the secondary coil, which is directly related to the relative position of the primary coil and the secondary coil;

[0028] The secondary output current is proportional to the midpoint voltage of the primary inverter bridge arm, and inversely proportional to the system operating frequency and the mutual inductance M between the primary coil and the secondary coil. Increasing the secondary output power, that is, increasing the secondary output current, can be achieved by increasing the midpoint voltage of the inverter bridge arm, or reducing the system operating frequency, or reducing the mutual inductance between the primary and secondary coils.

[0029] After fixing the original secondary side position and the inverter input voltage, the system operating frequency is reduced to increase the system output power. The setting range of the system operating frequency is not the wider the better, and it needs to be reasonably determined in accordance with system requirements and system characteristics.

[0030] The midpoint voltage of the inverter bridge arm is controlled by its input voltage, that is, the output voltage of the DC / DC converter and the inverter phase shift angle; the system operating frequency can be changed by adjusting the driving frequency of the four MOS tubes S1, S2, S3, and S4 of the inverter; the mutual inductance between the primary and secondary coils is directly related to the relative position of the primary and secondary coils. In a single charging process, the relative position of the two is not convenient to adjust directly, and will not change under most conditions. Therefore, the output current or output power is adjusted by changing the midpoint voltage of the inverter bridge arm and the system operating frequency.

[0031] The control method of the industrial-grade wireless charging system adopts the industrial-grade wireless charging system, which is characterized in that the output current or output power is adjusted by changing the inverter bridge arm midpoint voltage and the system operating frequency, and comprises the following steps:

[0032] S1. After the communication between the primary side and the secondary side is established, a charging request is initiated. The charging request includes the charging voltage, charging current or charging power. The charging request is initiated by the primary side or the secondary side.

[0033] S2, the primary side receives the charging instruction and enters the charging process, setting the initial operating frequency of the inverter to NkHz, which is the maximum frequency in the system operating frequency range; at the same time, the Buck voltage is raised from Vbuck_min to Vbuck_set, Vbuck_min is the minimum operating voltage of the Buck circuit, Vbuck_min<Vbuck_set<Vbuck_max, Vbuck_max is the maximum operating voltage of the Buck circuit;

[0034] S3, the inverter operating frequency is NkHz, and the Buck voltage reaches Vbuck_set;

[0035] S4, detecting whether the inverter current Iinv is less than the inverter current setting value Iinv_set, wherein Iinv_set<Iinv_max, Iinv_max is the maximum limit value of the inverter current;

[0036] S5. If the inverter current Iinv<Iinv_set, the Buck voltage is fixed at Vbuck_set and the inverter operating frequency is reduced;

[0037] S6. During the process of reducing the inverter operating frequency, monitor whether the inverter current Iinv is greater than or equal to Iinv_set;

[0038] S7, when the inverter current Iinv reaches the set value Iinv_set, the inverter operating frequency is fixed at this time, and the Buck voltage continues to be raised;

[0039] S8, until the target value is reached or the inverter current reaches the maximum value or the Buck voltage reaches the maximum value, the adjustment ends;

[0040] If the inverter current Iinv<Iinv_set is not established in step S4, then directly enter step S7, fix the inverter operating frequency at this time, that is, f=NkHz, and continue to increase the Buck voltage, and then enter step S8 until the target value is reached or the inverter current reaches the maximum value or the Buck voltage reaches the maximum value, and then the regulation ends;

[0041] Among them, Vbuck_set and Iinv_set are system control parameters, which can be flexibly set within the specified range according to system characteristics and requirements.

[0042] After adopting the present invention, the most basic wireless charging topology - SS topology is adopted in the system structure, which has a simple structure and reduces product cost and matching complexity. At the same time, in conjunction with the entire system structure and system characteristics, a control method for an industrial-grade wireless charging system is proposed, which enables the charging system to meet the output requirements within a specified range. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a structural schematic diagram of the industrial-grade wireless charging system of the present invention;

[0044] Figure 2 It is a circuit diagram of the industrial-grade wireless charging system of the present invention;

[0045] Figure 3 is a schematic diagram of the working state of the inverter applicable to the present invention;

[0046] Figure 4 is a schematic diagram of the working state of a rectifier applicable to the present invention;

[0047] Figure 5 A line graph showing the effect of frequency variation on output power within the charging range after the present invention is adopted;

[0048] Figure 6 It is a schematic flow chart of the control method of the present invention. DETAILED DESCRIPTION

[0049] An industrial-grade wireless charging system, see Figure 1-Figure 5 , which includes PFC, DC / DC converter, inverter, primary compensation network, coupling mechanism, secondary compensation network, and rectifier.

[0050] In specific implementation, PFC is used to convert AC power into DC voltage output. It is a single-phase AC grid input and DC voltage output. The output voltage range is 360V~550V, and the voltage can be adjusted and controlled according to system requirements;

[0051] The DC / DC converter is specifically a Buck circuit. When the inverter has a low-voltage input requirement, the DC / DC converter converts the PFC output DC voltage into the low voltage required by the system;

[0052] The inverter is a full-bridge inverter with variable frequency control and an operating frequency range of 79kHz to 90kHz. At this time, M=79, N=90. It converts DC power into AC power of a set frequency according to system requirements.

[0053] The inverter includes four MOS tubes, namely S1, S2, S3, and S4. The controlled parameters of the full-bridge inverter include the inverter bridge arm midpoint voltage UAB and the inverter current Iinv. The full-bridge inverter changes the inverter operating frequency by controlling the driving frequency of the four MOS tubes S1, S2, S3, and S4.

[0054] In the working range, the inverter load is weakly inductive, and the inverter bridge arm midpoint voltage UAB is always ahead of the inverter current Iinv in phase;

[0055] The inverter adopts phase-shift control, and phase-shift voltage regulation can be used as an auxiliary voltage regulation method;

[0056] The coupling mechanism includes a primary coil L1 and a secondary coil L2, and both the primary coil L1 and the secondary coil L2 are independent coils wound by Litz wire;

[0057] The primary compensation network is composed of two groups of capacitors C1_a and C1_b, which are symmetrically distributed relative to the primary coil L1. The secondary compensation network is composed of two groups of capacitors C2_a and C2_b, which are symmetrically distributed relative to the secondary coil L2.

[0058] The rectifier is used to rectify the AC power induced by the secondary side into DC power and charge the battery of the device. The rectifier consists of 4 MOS tubes in a full-bridge structure. The 4 MOS tubes are Q1, Q2, Q3, and Q4. The 4 MOS tubes are used for synchronous rectification control. The parameters include the rectifier input current i in , rectifier bridge arm midpoint voltage Uab, rectifier output current i out ;

[0059] Rectifier input current i in It is generated by the induction of the secondary coil, and its frequency is consistent with the inverter frequency on the primary side. When the inverter on the primary side performs frequency conversion control, the rectifier input current i in As it changes, the rectifier has a frequency tracking function and adjusts the synchronous rectification working frequency accordingly, that is, changes the drive control frequency of Q1, Q2, Q3, and Q4;

[0060] In the driving waveforms of Q1, Q2, Q3, and Q4, the driving waveforms of Q1 and Q4 are in phase, the driving waveforms of Q2 and Q3 are in phase, the phase difference between Q1 and Q2 is 180 degrees, and the phase difference between Q3 and Q4 is 180 degrees (see Figure 4 );

[0061] The rectifier has the function of tracking the primary frequency, which is achieved by: a. detecting the frequency of the induced voltage of the secondary coil; b. detecting the frequency of the induced current of the secondary coil; c. detecting the frequency of the voltage across the capacitor C2_a or C2_b; d. detecting the frequency of the rectifier bridge arm midpoint voltage Uab; the above four methods realize the function of the secondary rectifier tracking the primary frequency, and can be selected or used in combination;

[0062] The rectifier bridge arm midpoint voltage Uab is clamped by the rechargeable battery voltage, and the platform voltage is equal to the rechargeable battery voltage;

[0063] The PFC, DC / DC converter, inverter, primary compensation network, and primary coil form the primary side, and the secondary coil, secondary compensation network, and rectifier form the secondary side.

[0064] The input end of the PFC is connected to the single-phase AC power grid, the output end of the PFC is connected to the input end of the DC / DC converter, the output end of the DC / DC converter is connected to the inverter, the two groups of corresponding capacitors of the primary compensation network are connected to the inverter arrangement, the coupling mechanism and the primary compensation network and the secondary compensation network form a series resonant topology, the two groups of capacitors of the secondary compensation network are connected to the rectifier arrangement, and the output end of the rectifier is connected to the battery.

[0065] In specific implementation, the primary coil and the primary compensation network, the secondary coil and the secondary compensation network all form a series resonant topology with a constant current output characteristic. The secondary output current can be expressed as Expression; where I2 is the secondary coil current; UAB is the primary inverter bridge arm midpoint voltage; ω is the system operating angular frequency, and the frequency relationship is ω=2πf; M is the mutual inductance between the primary coil and the secondary coil, which is directly related to the relative position of the primary coil and the secondary coil;

[0066] The secondary output current is proportional to the midpoint voltage of the primary inverter bridge arm, and inversely proportional to the system operating frequency and the mutual inductance M between the primary coil and the secondary coil. Increasing the secondary output power, that is, increasing the secondary output current, can be achieved by increasing the midpoint voltage of the inverter bridge arm, or reducing the system operating frequency, or reducing the mutual inductance between the primary and secondary coils.

[0067] After fixing the original secondary side position and the inverter input voltage, the system operating frequency is reduced to increase the system output power; the setting range of the system operating frequency is not the wider the better, and it needs to be reasonably determined in accordance with system requirements and system characteristics.

[0068] The midpoint voltage of the inverter bridge arm is controlled by its input voltage, that is, the output voltage of the DC / DC converter and the inverter phase shift angle; the system operating frequency can be changed by adjusting the drive frequency of the four MOS tubes S1, S2, S3, and S4 of the inverter; the mutual inductance between the primary and secondary coils is directly related to the relative position of the primary and secondary coils. In a single charging process, the relative position of the two is not convenient to adjust directly, and will not change under most conditions. Therefore, by changing the midpoint voltage of the inverter bridge arm and the system operating frequency (see Figure 5 ) to adjust the output current or output power.

[0069] Control method of industrial wireless charging system, see Figure 6:Adjusting the output current or output power by changing the inverter bridge arm midpoint voltage and the system operating frequency includes the following steps:

[0070] S1. After the communication between the primary side and the secondary side is established, a charging request is initiated. The charging request includes the charging voltage, charging current or charging power. The charging request is initiated by the primary side or the secondary side.

[0071] S2, the primary side receives the charging instruction and enters the charging process, setting the initial operating frequency of the inverter to 90kHz, which is the maximum frequency in the system operating frequency range; at the same time, the Buck voltage is raised from Vbuck_min to Vbuck_set, Vbuck_min is the minimum operating voltage of the Buck circuit, Vbuck_min<Vbuck_set<Vbuck_max, Vbuck_max is the maximum operating voltage of the Buck circuit;

[0072] S3, the inverter operating frequency is 90kHz, and the Buck voltage reaches Vbuck_set;

[0073] S4, detecting whether the inverter current Iinv is less than the inverter current setting value Iinv_set, wherein Iinv_set<Iinv_max, Iinv_max is the maximum limit value of the inverter current;

[0074] S5. If the inverter current Iinv<Iinv_set, the Buck voltage is fixed at Vbuck_set and the inverter operating frequency is reduced;

[0075] S6. During the process of reducing the inverter operating frequency, monitor whether the inverter current Iinv is greater than or equal to Iinv_set;

[0076] S7, when the inverter current Iinv reaches the set value Iinv_set, the inverter operating frequency is fixed at this time, and the Buck voltage continues to be raised;

[0077] S8, until the target value is reached or the inverter current reaches the maximum value or the Buck voltage reaches the maximum value, the adjustment ends;

[0078] If the inverter current Iinv<Iinv_set in step S4 is not established, then directly enter step S7, fix the inverter operating frequency at this time, that is, f=90kHz, and continue to increase the Buck voltage, and then enter step S8 until the target value is reached or the inverter current reaches the maximum value or the Buck voltage reaches the maximum value, and then the adjustment is ended;

[0079] Among them, Vbuck_set and Iinv_set are system control parameters, which can be flexibly set within the specified range according to system characteristics and requirements.

[0080] The most basic wireless charging topology - SS topology is adopted in the system structure, which has a simple structure and reduces product cost and matching complexity. At the same time, in combination with the entire system structure and system characteristics, a control method for an industrial-grade wireless charging system is proposed, which enables the charging system to meet the output requirements within the specified range.

[0081] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0082] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An industrial-grade wireless charging system, characterized in that: It includes: PFC, which is used to convert AC power into DC voltage output; A DC / DC converter, which converts the PFC output DC voltage into a low voltage required by the system; Inverter, which converts DC power into AC power of a set frequency according to system requirements; Primary side compensation network; A coupling mechanism, comprising a primary coil and a secondary coil, wherein the primary coil and the secondary coil are independent coils wound by Litz wire; Secondary side compensation network; and a rectifier for rectifying the alternating current induced on the secondary side into direct current and charging the battery of the device; The DC / DC converter is a Buck circuit; The primary compensation network is composed of two groups of capacitors C1_a and C1_b, which are symmetrically distributed relative to the primary coil L1, and the secondary compensation network is composed of two groups of capacitors C2_a and C2_b, which are symmetrically distributed relative to the secondary coil L2; The PFC, DC / DC converter, inverter, primary compensation network, and primary coil are combined to form a primary side, and the secondary coil, secondary compensation network, and rectifier are combined to form a secondary side; The input end of the PFC is connected to a single-phase AC power grid, the output end of the PFC is connected to the input end of the DC / DC converter, the output end of the DC / DC converter is connected to an inverter, the two groups of corresponding capacitors of the primary compensation network are connected to the inverter arrangement, the coupling mechanism and the primary compensation network and the secondary compensation network form a series resonant topology, the two groups of capacitors of the secondary compensation network are connected to the rectifier arrangement, and the output end of the rectifier is connected to a battery.

2. An industrial-grade wireless charging system according to claim 1, characterized in that: The inverter is a full-bridge inverter, which includes four MOS tubes, namely S1, S2, S3, and S4. The controlled parameters of the full-bridge inverter include the inverter bridge arm midpoint voltage UAB and the inverter current Iinv; The full-bridge inverter realizes the change of the inverter operating frequency by controlling the driving frequency of the four MOS tubes S1, S2, S3, and S4, and the operating frequency range is MkHz to NkHz.

3. An industrial-grade wireless charging system according to claim 2, characterized in that: In the working range, the inverter load is weakly inductive, and the inverter bridge arm midpoint voltage UAB is always kept ahead of the inverter current Iinv in phase; The inverter adopts phase shift control, and phase shift voltage regulation is used as an auxiliary voltage regulation method.

4. The industrial-grade wireless charging system according to claim 1, characterized in that: The rectifier is composed of four MOS tubes forming a full-bridge structure. The four MOS tubes are Q1, Q2, Q3, and Q4. The four MOS tubes are used for synchronous rectification control. The parameters include the rectifier input current i in , rectifier bridge arm midpoint voltage Uab, rectifier output current i out ; The rectifier input current i in It is generated by the induction of the secondary coil, and its frequency is consistent with the inverter frequency on the primary side. When the inverter on the primary side performs frequency conversion control, the rectifier input current i in As the current changes, the rectifier has a frequency tracking function and adjusts the synchronous rectification operating frequency accordingly, that is, changes the drive control frequency of Q1, Q2, Q3, and Q4.

5. An industrial-grade wireless charging system according to claim 4, characterized in that: Among the driving waveforms of Q1, Q2, Q3, and Q4, the driving waveforms of Q1 and Q4 are in phase, the driving waveforms of Q2 and Q3 are in phase, the phase difference between Q1 and Q2 is 180 degrees, and the phase difference between Q3 and Q4 is 180 degrees.

6. An industrial-grade wireless charging system according to claim 4, characterized in that: The rectifier has the function of tracking the primary frequency, which is implemented by: a detecting the frequency of the induced voltage of the secondary coil; b detecting the frequency of the induced current of the secondary coil; c detecting the frequency of the voltage across the capacitor C2_a or C2_b; d detecting the frequency of the rectifier bridge arm midpoint voltage Uab; the above four methods realize the function of the secondary rectifier tracking the primary frequency, and can be selected or used in combination.

7. An industrial-grade wireless charging system according to claim 4, characterized in that: The rectifier bridge arm midpoint voltage Uab is clamped by the rechargeable battery voltage, and the platform voltage is equal to the rechargeable battery voltage.

8. The industrial-grade wireless charging system according to claim 1, characterized in that: The primary coil and primary compensation network, the secondary coil and secondary compensation network all form a series resonant topology with a constant current output characteristic. The secondary output current can be expressed as Expression; where I2 is the secondary coil current; UAB is the midpoint voltage of the primary inverter bridge arm; ω is the system operating angular frequency, and its relationship with the frequency is ω=2πf; M is the mutual inductance between the primary coil and the secondary coil, which is directly related to the relative positions of the primary coil and the secondary coil.

9. An industrial-grade wireless charging system according to claim 8, characterized in that: The secondary output current is proportional to the midpoint voltage of the primary inverter bridge arm, and inversely proportional to the system operating frequency and the mutual inductance M between the primary coil and the secondary coil. Increasing the secondary output power, that is, increasing the secondary output current, can be achieved by increasing the midpoint voltage of the inverter bridge arm, or reducing the system operating frequency, or reducing the mutual inductance between the primary and secondary coils. After fixing the original secondary side position and the inverter input voltage, the system operating frequency is reduced to increase the system output power. The setting range of the system operating frequency is not the wider the better, and it needs to be reasonably determined in accordance with system requirements and system characteristics. The midpoint voltage of the inverter bridge arm is controlled by its input voltage, that is, the output voltage of the DC / DC converter and the inverter phase shift angle; the system operating frequency can be changed by adjusting the driving frequency of the four MOS tubes S1, S2, S3, and S4 of the inverter; The mutual inductance between the primary and secondary coils is directly related to the relative positions of the primary and secondary coils. During a single charging process, the relative positions of the two are not convenient to adjust directly, and will not change under most conditions. Therefore, the output current or output power is adjusted by changing the inverter bridge arm midpoint voltage and the system operating frequency.

10. A control method for an industrial-grade wireless charging system, which adopts an industrial-grade wireless charging system as claimed in any one of claims 1 to 9, characterized in that: The output current or output power is adjusted by changing the inverter bridge arm midpoint voltage and the system operating frequency, which includes the following steps: S1. After the communication between the primary side and the secondary side is established, a charging request is initiated. The charging request includes the charging voltage, charging current or charging power. The charging request is initiated by the primary side or the secondary side. S2, the primary side receives the charging instruction and enters the charging process, setting the initial operating frequency of the inverter to NkHz, which is the maximum frequency in the system operating frequency range; at the same time, the Buck voltage is raised from Vbuck_min to Vbuck_set, Vbuck_min is the minimum operating voltage of the Buck circuit, Vbuck_min<Vbuck_set<Vbuck_max, Vbuck_max is the maximum operating voltage of the Buck circuit; S3, the inverter operating frequency is NkHz, and the Buck voltage reaches Vbuck_set; S4, detecting whether the inverter current Iinv is less than the inverter current setting value Iinv_set, wherein Iinv_set<Iinv_max, Iinv_max is the maximum limit value of the inverter current; S5. If the inverter current Iinv<Iinv_set, the Buck voltage is fixed at Vbuck_set and the inverter operating frequency is reduced; S6. During the process of reducing the inverter operating frequency, monitor whether the inverter current Iinv is greater than or equal to Iinv_set; S7, when the inverter current Iinv reaches the set value Iinv_set, the inverter operating frequency is fixed at this time, and the Buck voltage continues to be raised; S8, until the target value is reached or the inverter current reaches the maximum value or the Buck voltage reaches the maximum value, the adjustment ends; If the inverter current Iinv<Iinv_set is not established in step S4, then directly enter step S7, fix the inverter operating frequency at this time, that is, f=NkHz, and continue to increase the Buck voltage, and then enter step S8 until the target value is reached or the inverter current reaches the maximum value or the Buck voltage reaches the maximum value, and then the regulation ends; Among them, Vbuck_set and Iinv_set are system control parameters, which can be flexibly set within the specified range according to system characteristics and requirements.

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