A bridgeless totem-pole PFC power supply circuit for a wireless charging system and a control method thereof

Abstract

This invention discloses and provides a low-cost, simple-structured totem-pole PFC power supply circuit and its control method for wireless charging systems, which can reduce total harmonic distortion and improve the performance of wireless charging systems. The bridgeless totem-pole PFC power supply circuit for wireless charging systems in this invention includes an AC power supply V... ac The components include inductors Lm1 and Lm2, a first high-speed power bridge arm, a second high-speed power bridge arm, a slow-speed rectifier bridge arm, an output filter capacitor C, a load resistor R, and a voltage output V. This invention is applicable to the field of power electronics technology.

Description

Technical Field

[0001] This invention relates to a bridgeless totem pole type PFC power supply circuit for wireless charging systems and its control method. Background Technology

[0002] Due to economic reasons and environmental concerns, the efficiency of power conversion systems is becoming increasingly important. The efficiency level defined in 80 Plus requires 96% to achieve Titanium certification. Achieving such high efficiency presents significant design challenges for power supply companies using traditional topologies.

[0003] An offline power supply consists of power factor correction (PFC) and a DC / DC converter. PFC forces the input current to vary with the input voltage, thus making any electrical load behave as a resistor. To improve efficiency, different PFC topologies have been investigated, including conventional PFC, semi-bridgeless PFC, bidirectional bridgeless PFC, and totem-pole bridgeless PFC. Among all these different PFC topologies, totem-pole PFC has attracted increasing attention due to its minimal component count, lowest conduction losses, and highest efficiency.

[0004] LCC-type wireless charging systems require a stable and controllable DC input power supply. Due to the parameter sensitivity of wireless charging systems, the requirements for EMC and power conduction losses in the PFC switching power supply are relatively high. Therefore, a more efficient PFC with lower electromagnetic interference is needed as the AC-DC converter front end. Totem-pole PFC is a very suitable topology choice.

[0005] Although the concept of totem pole PFC has existed for many years, technical application challenges have hindered its widespread use.

[0006] First, totem-pole PFC cannot operate in continuous conduction mode (CCM) due to the slow reverse recovery of the MOSFET body diode. Second, there is an inherent problem with the totem-pole PFC topology: the input current has a large spike at the AC zero crossing. These spikes disrupt the current waveform and cause the total harmonic distortion (THD) to fail to meet specifications. Third, Q3 and Q4 alternate between the PFC activation switch and the synchronous rectification switch every half AC cycle. This alternation requires the controller to provide a pulse width modulation (PWM) waveform with either D (duty cycle) or 1-D based on the positive or negative AC cycle.

[0007] These issues will limit the application of totem pole PFC technology in wireless charging systems. Therefore, the original topology needs to be improved, and new advanced control algorithms need to be developed to control the switches to turn on in a special sequence, and each switch to perform a soft-start mechanism, thereby greatly reducing current spikes. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a totem pole PFC power circuit and its control method that is low in cost, simple in structure, and applicable to wireless charging systems, which can reduce total harmonic distortion and improve the wireless charging system.

[0009] The bridgeless totem pole type PFC power supply circuit for wireless charging systems in this invention includes an AC power supply V. ac The components include inductors Lm1 and Lm2, a first high-speed power bridge arm, a second high-speed power bridge arm, a slow rectifier bridge arm, an output filter capacitor C, a load resistor R, and a voltage output V. The positive terminals of inductors Lm1 and Lm2 are respectively connected to the AC power supply V. ac The positive terminal of the inductor is electrically connected. Inductor Lm1 and inductor Lm2 are connected in parallel. The first high-speed power bridge arm, the second high-speed power bridge arm, the slow rectifier bridge arm, the output filter capacitor C, the load resistor R, and the voltage output V are connected in parallel in sequence. The negative terminal of inductor Lm1 is electrically connected to the first high-speed power bridge arm, and the negative terminal of inductor Lm2 is electrically connected to the second high-speed power bridge arm. The AC power supply V... ac The negative terminal is electrically connected to the slow rectifier bridge arm.

[0010] The first high-speed power bridge arm includes a first MOSFET and a second MOSFET. The source S of the first MOSFET is electrically connected to the drain D of the second MOSFET. The negative terminal of the inductor Lm1 is electrically connected to the source S of the first MOSFET and the drain D of the second MOSFET.

[0011] The second high-speed power bridge arm includes a third MOSFET and a fourth MOSFET. The source S of the third MOSFET is electrically connected to the drain D of the fourth MOSFET. The negative terminal of the inductor Lm2 is electrically connected to the source S of the third MOSFET and the drain D of the fourth MOSFET, respectively.

[0012] The slow-speed rectifier bridge arm includes a fifth MOSFET and a sixth MOSFET. The source (S) of the fifth MOSFET is electrically connected to the drain (D) of the sixth MOSFET. The AC power supply V... acThe negative terminal is electrically connected to the source S of the fifth MOSFET and the drain D of the sixth MOSFET, respectively.

[0013] The drain D of the first MOSFET, the drain D of the third MOSFET, the drain D of the fifth MOSFET, the positive terminal of the output filter capacitor C, the positive terminal of the load resistor R, and the positive terminal of the voltage output V are electrically connected to each other. The source S of the second MOSFET, the source S of the fourth MOSFET, the source S of the sixth MOSFET, the negative terminal of the output filter capacitor C, the negative terminal of the load resistor R, and the negative terminal of the voltage output V are electrically connected to each other.

[0014] The bridgeless totem pole type PFC power control method for wireless charging systems implemented in this invention using the above-mentioned bridgeless totem pole type PFC power circuit includes the following steps:

[0015] A. Power on the bridgeless totem pole type PFC power supply;

[0016] B. Set the voltage boost slope, and the output voltage will increase from zero.

[0017] C. Determine the voltage regulation status of the output voltage. If it is over-voltage or under-voltage, return to step B to modify the voltage boost slope and re-determine the voltage regulation status until the output voltage is determined to be regulated.

[0018] D. After the output voltage is determined to be regulated, it is determined whether the output voltage value has reached the standard value. If it has not reached the standard value, the voltage will continue to be increased until the output voltage reaches the standard value. Once the output voltage value reaches the standard value, the start-up phase ends and the working phase begins.

[0019] E. Determine the working range, corresponding to three stages, and use different control algorithms for each: use the normal working algorithm under normal working conditions; use the positive-negative algorithm during the period when the AC voltage changes from the positive half-cycle to the negative half-cycle; use the negative-positive algorithm during the period when the AC voltage changes from the negative half-cycle to the positive half-cycle.

[0020] F. Complete the algorithm calculation and output the corresponding control quantity;

[0021] G. Perform the corresponding driving action according to the control quantity;

[0022] H. Determine whether the driving action obtained in step G is a shutdown action. If it is, execute the shutdown action; otherwise, return to step E to continue the judgment of the working area.

[0023] The normal working algorithm used in step E under normal working conditions includes the following steps:

[0024] E11. The inductor current I in the bridgeless totem pole type PFC power supply circuit for the wireless charging system is respectively... Lm AC voltage V AC and output voltage V out The sampled values ​​are then processed and transformed before being input into the control loop;

[0025] E12. The output voltage V out The output voltage error V is obtained by comparing it with the target value. out_err The output is then fed into the voltage loop PI for proportional-integral calculation to obtain the control quantity of the output voltage;

[0026] E13. The voltage loop PI output control quantity is fed into the multiplier, and the corresponding multiplication operation is performed to obtain the control quantity of the target power value;

[0027] E14. The control quantity of the target power value and the AC voltage V AC The values ​​after proportional calculation are multiplied to calculate the control quantity of the inductor current and perform phase detection at the same time.

[0028] E15. After multiplication phase detection, the control quantity of the inductor current is obtained, and it is compared with the inductor current I. Lm The sampled values ​​are compared, and then the current loop PI is used for PI calculation, finally obtaining the output control quantity of the current loop PI.

[0029] E16. PWM is generated based on the output control quantity of the final current loop PI to obtain the corresponding high-speed bridge arm drive signal;

[0030] E17. The slow-speed transistor operates in normal mode based on the AC voltage V. AC The positive and negative values ​​are used for driving, in the AC voltage V AC When the value is positive, Q1 of the fifth MOSFET is off and Q2 of the sixth MOSFET is on. When the AC voltage Vac is negative, Q1 of the fifth MOSFET is on and Q2 of the sixth MOSFET is off.

[0031] The positive-negative algorithm used in step E during the transition of AC voltage from the negative half-cycle to the positive half-cycle includes the following steps:

[0032] E21. The inductor current I in the bridgeless totem pole type PFC power supply circuit for the wireless charging system is respectively... Lm AC voltage V AC and output voltage V out The sampled values ​​are then processed and transformed before being input into the control loop;

[0033] E22. The output voltage V out The output voltage error V is obtained by comparing it with the target value. out_err The output is then fed into the voltage loop PI for proportional-integral calculation to obtain the control quantity of the output voltage;

[0034] E23. The voltage loop PI output control quantity is fed into the multiplier, and the corresponding multiplication operation is performed to obtain the control quantity of the target power value;

[0035] E24. The bottom loop generates a triangular ramp with a positive slope. The triangular ramp can control three parameters: ramp slope, ramp time, and ramp enable, and generate a corresponding triangular ramp.

[0036] E25. By using a multiplier, the positive triangular ramp signal and the calculated power value are superimposed to obtain a calculated power value that varies according to the ramp ratio.

[0037] E26. The control signal after the superposition of ramps drives the first high-speed power bridge arm and the second high-speed power bridge arm, but only gives the drive signal to the second MOSFET and the Q3 of the fourth MOSFET, that is, the lower transistor of the two high-speed power bridge arms.

[0038] E27. The drive signal of the first MOSFET and the Q4 of the third MOSFET remains at 0, that is, there is no drive level;

[0039] E28. The slow rectifier bridge arm is in the dead zone at this time, and the drive signals of the fifth MOSFET and the sixth MOSFET are both 0, that is, there is no drive level.

[0040] The negative-positive algorithm used in step E during the transition of AC voltage from the negative half-cycle to the positive half-cycle includes the following steps:

[0041] E31. The inductor current I in the bridgeless totem pole type PFC power supply circuit for the wireless charging system is respectively... Lm AC voltage V AC and output voltage V out The sampled values ​​are then processed and transformed before being input into the control loop;

[0042] E32. The output voltage V out The output voltage error V is obtained by comparing it with the target value. out_err The output is then fed into the voltage loop PI for proportional-integral calculation to obtain the control quantity of the output voltage;

[0043] E33. The voltage loop PI output control quantity is fed into the multiplier, and the corresponding multiplication operation is performed to obtain the control quantity of the target power value;

[0044] E34. The bottom loop generates a triangular ramp with a positive slope. The triangular ramp can control three parameters: ramp slope, ramp time, and ramp enable, and generate a corresponding triangular ramp.

[0045] E35. By using a multiplier, the positive triangular ramp signal and the calculated power value are superimposed to obtain a calculated power value that varies according to the ramp ratio.

[0046] E36. The control quantity after the superposition of ramps is used to drive the first high-speed power bridge arm and the second high-speed power bridge arm, but only the drive signal is given to the Q4 of the first MOSFET and the third MOSFET, that is, the upper transistor of the two high-speed power bridge arms.

[0047] E37. The drive signals of the second MOSFET of the high-speed power bridge arm and the Q3 of the fourth MOSFET are kept at 0, that is, there is no drive level;

[0048] E38. The slow rectifier bridge arm is in the dead zone at this time, and the drive signals of the fifth MOSFET and the sixth MOSFET are both 0, that is, there is no drive level.

[0049] Beneficial Effects: This invention improves upon totem-pole PFC technology, replacing it with a derived totem-pole topology for application in wireless charging systems. Even without using GaN FETs, traditional MOSFETs can enable totem-pole PFC to operate in continuous conduction mode (CCM). It reduces or even eliminates the large spikes in input current at AC zero-crossing, thereby lowering total harmonic distortion (THD) and allowing totem-pole PFC to be used in wireless charging systems. The power transistor alternates between the PFC activation switch and the synchronous rectification switch every half AC cycle. This forms a soft-switching technology adapted to wireless charging applications, controlling the PWM waveform of the power transistor based on the positive or negative AC voltage cycle, thereby improving the performance of the wireless charging system. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of a traditional totem pole PFC circuit.

[0051] Figure 2 This is a schematic diagram of the circuit principle of the bridgeless totem pole type PFC power supply circuit for wireless charging system in this invention.

[0052] Figure 3 This is a flowchart illustrating the control method of the bridgeless totem pole type PFC power supply for a wireless charging system in this invention.

[0053] Figure 4This is a block diagram of the control loop of the present invention under normal operating conditions;

[0054] Figure 5 This is a schematic diagram of the positive-negative algorithm used in this invention during the transition of AC voltage from the positive half-cycle to the negative half-cycle.

[0055] Figure 6 This is a schematic diagram of the negative-positive algorithm used in this invention during the transition of AC voltage from the negative half-cycle to the positive half-cycle. Detailed Implementation

[0056] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 As shown, the bridgeless totem-pole type PFC power supply circuit for wireless charging systems in this invention includes an AC power supply V. ac The components include inductors Lm1 and Lm2, a first high-speed power bridge arm, a second high-speed power bridge arm, a slow rectifier bridge arm, an output filter capacitor C, a load resistor R, and a voltage output V. The positive terminals of inductors Lm1 and Lm2 are respectively connected to the AC power supply V. ac The positive terminal of the inductor is electrically connected. Inductor Lm1 and inductor Lm2 are connected in parallel. The first high-speed power bridge arm, the second high-speed power bridge arm, the slow rectifier bridge arm, the output filter capacitor C, the load resistor R, and the voltage output V are connected in parallel in sequence. The negative terminal of inductor Lm1 is electrically connected to the first high-speed power bridge arm, and the negative terminal of inductor Lm2 is electrically connected to the second high-speed power bridge arm. The AC power supply V... ac The negative terminal is electrically connected to the slow rectifier bridge arm.

[0057] The first high-speed power bridge arm includes a first MOSFET and a second MOSFET. The source S of the first MOSFET is electrically connected to the drain D of the second MOSFET. The negative terminal of the inductor Lm1 is electrically connected to the source S of the first MOSFET and the drain D of the second MOSFET.

[0058] The second high-speed power bridge arm includes a third MOSFET and a fourth MOSFET. The source S of the third MOSFET is electrically connected to the drain D of the fourth MOSFET. The negative terminal of the inductor Lm2 is electrically connected to the source S of the third MOSFET and the drain D of the fourth MOSFET, respectively.

[0059] The slow-speed rectifier bridge arm includes a fifth MOSFET and a sixth MOSFET. The source (S) of the fifth MOSFET is electrically connected to the drain (D) of the sixth MOSFET. The AC power supply V... ac The negative terminal is electrically connected to the source S of the fifth MOSFET and the drain D of the sixth MOSFET, respectively.

[0060] The drain D of the first MOSFET, the drain D of the third MOSFET, the drain D of the fifth MOSFET, the positive terminal of the output filter capacitor C, the positive terminal of the load resistor R, and the positive terminal of the voltage output V are electrically connected to each other. The source S of the second MOSFET, the source S of the fourth MOSFET, the source S of the sixth MOSFET, the negative terminal of the output filter capacitor C, the negative terminal of the load resistor R, and the negative terminal of the voltage output V are electrically connected to each other.

[0061] The main differences between the main topology of the totem pole PFC in this invention and the traditional totem pole PFC are as follows:

[0062] The number of high-speed power bridge arms has increased from one to two, and the number of inductors has also increased to two, which improves the input AC current I. ac The size of the [something] increases the output power;

[0063] The rectifier diodes in the traditional topology are replaced by slow rectifier bridge arms for rectification, and can also be used to implement advanced control algorithms to improve the circuit, reduce electromagnetic radiation and interference, making it more suitable for wireless charging systems.

[0064] The input AC current ILm sampling point is set at the common terminal of the two inductors to collect the total inductor current controlled by the high-speed power bridge arm;

[0065] Sampled AC input voltage V ac and output voltage V out It is used for loop calculation.

[0066] The present invention utilizes the aforementioned bridgeless totem pole type PFC power supply circuit to implement a bridgeless totem pole type PFC power control method for a wireless charging system. This method requires judgment based on the system's operating status and executes the corresponding control algorithm based on the judgment result. The method includes the following steps:

[0067] A. Power on the bridgeless totem pole type PFC power supply;

[0068] B. Set the voltage boost slope, and the output voltage will increase from zero.

[0069] C. Determine the voltage regulation status of the output voltage. If it is over-voltage or under-voltage, return to step B to modify the voltage boost slope and re-determine the voltage regulation status until the output voltage is determined to be regulated.

[0070] D. After the output voltage is determined to be regulated, it is determined whether the output voltage value has reached the standard value. If it has not reached the standard value, the voltage will continue to be increased until the output voltage reaches the standard value. Once the output voltage value reaches the standard value, the start-up phase ends and the working phase begins.

[0071] E. Determine the working range and use different control algorithms for the three stages: use the normal working algorithm under normal working conditions; use the positive-negative algorithm when the AC voltage changes from the positive half-cycle to the negative half-cycle; use the negative-positive algorithm when the AC voltage changes from the negative half-cycle to the positive half-cycle.

[0072] F. Complete the algorithm calculation and output the corresponding control quantity;

[0073] G. Perform the corresponding driving action according to the control quantity;

[0074] H. Determine whether the driving action obtained in step G is a shutdown action. If it is, execute the shutdown action; otherwise, return to step E to continue the judgment of the working area.

[0075] Figure 4 This is a control loop block diagram of the normal operating state of the present invention, showing the control loop situation of the present invention under normal operating conditions. That is, except for the following situations, the operation process follows the calculation of this control loop, but in other situations, the relevant algorithm will be executed.

[0076] The normal working algorithm used in step E under normal working conditions includes the following steps:

[0077] E11. The inductor current I in the bridgeless totem pole type PFC power supply circuit for the wireless charging system is respectively... Lm AC voltage V AC and output voltage V out The sampled values ​​are then processed and transformed before being input into the control loop;

[0078] E12. The output voltage V out The output voltage error V is obtained by comparing it with the target value. out_err The output is then fed into the voltage loop PI for proportional-integral calculation to obtain the control quantity of the output voltage;

[0079] E13. The voltage loop PI output control quantity is fed into the multiplier, and the corresponding multiplication operation is performed to obtain the control quantity of the target power value;

[0080] E14. The control quantity of the target power value and the AC voltage V AC The values ​​after proportional calculation are multiplied to calculate the control quantity of the inductor current and perform phase detection at the same time.

[0081] E15. After multiplication phase detection, the control quantity of the inductor current is obtained, and it is compared with the inductor current I. Lm The sampled values ​​are compared, and then the current loop PI is used for PI calculation, finally obtaining the output control quantity of the current loop PI.

[0082] E16. PWM is generated based on the output control quantity of the final current loop PI to obtain the corresponding high-speed bridge arm drive signal;

[0083] E17. The slow-speed transistor operates in normal mode based on the AC voltage V. AC The positive and negative values ​​are used for driving, in the AC voltage V AC When the value is positive, Q1 of the fifth MOSFET is off and Q2 of the sixth MOSFET is on. When the AC voltage Vac is negative, Q1 of the fifth MOSFET is on and Q2 of the sixth MOSFET is off.

[0084] The positive-negative algorithm used in step E during the transition of AC voltage from the negative half-cycle to the positive half-cycle includes the following steps:

[0085] E21. The inductor current I in the bridgeless totem pole type PFC power supply circuit for the wireless charging system is respectively... Lm AC voltage V AC and output voltage V out The sampled values ​​are then processed and transformed before being input into the control loop;

[0086] E22. The output voltage V out The output voltage error V is obtained by comparing it with the target value. out_err The output is then fed into the voltage loop PI for proportional-integral calculation to obtain the control quantity of the output voltage;

[0087] E23. The voltage loop PI output control quantity is fed into the multiplier, and the corresponding multiplication operation is performed to obtain the control quantity of the target power value;

[0088] E24. The bottom loop generates a triangular ramp with a positive slope. The triangular ramp can control three parameters: ramp slope, ramp time, and ramp enable, and generate a corresponding triangular ramp.

[0089] E25. By using a multiplier, the positive triangular ramp signal and the calculated power value are superimposed to obtain a calculated power value that varies according to the ramp ratio.

[0090] E26. The control signal after the superposition of ramps drives the first high-speed power bridge arm and the second high-speed power bridge arm, but only gives the drive signal to the second MOSFET and the Q3 of the fourth MOSFET, that is, the lower transistor of the two high-speed power bridge arms.

[0091] E27. The drive signal of the first MOSFET and the Q4 of the third MOSFET remains at 0, that is, there is no drive level;

[0092] E28. The slow rectifier bridge arm is in the dead zone at this time, and the drive signals of the fifth MOSFET and the sixth MOSFET are both 0, that is, there is no drive level.

[0093] The negative-positive algorithm used in step E during the transition of AC voltage from the negative half-cycle to the positive half-cycle includes the following steps:

[0094] E31. The inductor current I in the bridgeless totem pole type PFC power supply circuit for the wireless charging system is respectively... Lm AC voltage V AC and output voltage V out The sampled values ​​are then processed and transformed before being input into the control loop;

[0095] E32. The output voltage V out The output voltage error V is obtained by comparing it with the target value. out_err The output is then fed into the voltage loop PI for proportional-integral calculation to obtain the control quantity of the output voltage;

[0096] E33. The voltage loop PI output control quantity is fed into the multiplier, and the corresponding multiplication operation is performed to obtain the control quantity of the target power value;

[0097] E34. The bottom loop generates a triangular ramp with a positive slope. The triangular ramp can control three parameters: ramp slope, ramp time, and ramp enable, and generate a corresponding triangular ramp.

[0098] E35. By using a multiplier, the positive triangular ramp signal and the calculated power value are superimposed to obtain a calculated power value that varies according to the ramp ratio.

[0099] E36. The control quantity after the superposition of ramps is used to drive the first high-speed power bridge arm and the second high-speed power bridge arm, but only the drive signal is given to the Q4 of the first MOSFET and the third MOSFET, that is, the upper transistor of the two high-speed power bridge arms.

[0100] E37. The drive signals of the second MOSFET of the high-speed power bridge arm and the Q3 of the fourth MOSFET are kept at 0, that is, there is no drive level;

[0101] E38. The slow rectifier bridge arm is in the dead zone at this time, and the drive signals of the fifth MOSFET and the sixth MOSFET are both 0, that is, there is no drive level.

[0102] This invention relates to switching power supply technology for AC-DC conversion in the front end of wireless charging systems within the field of power electronics technology.

Claims

1. A control method for a bridgeless totem-pole type PFC power supply for a wireless charging system, wherein, Bridgeless totem pole type PFC power supply includes AC power supply It also includes inductors Lm1 and Lm2, a first high-speed power bridge arm, a second high-speed power bridge arm, a slow rectifier bridge arm, an output filter capacitor C, a load resistor R, and a voltage output V. The positive terminals of inductors Lm1 and Lm2 are respectively connected to the AC power supply. The positive terminal of the AC power supply is electrically connected. Inductors Lm1 and Lm2 are connected in parallel. The first high-speed power bridge arm, the second high-speed power bridge arm, the slow rectifier bridge arm, the output filter capacitor C, the load resistor R, and the voltage output V are connected in parallel in sequence. The negative terminal of inductor Lm1 is electrically connected to the first high-speed power bridge arm, and the negative terminal of inductor Lm2 is electrically connected to the second high-speed power bridge arm. The negative terminal is electrically connected to the slow rectifier bridge arm; The first high-speed power bridge arm includes a first MOSFET and a second MOSFET. The source S of the first MOSFET is electrically connected to the drain D of the second MOSFET. The negative terminal of the inductor Lm1 is electrically connected to the source S of the first MOSFET and the drain D of the second MOSFET, respectively. The second high-speed power bridge arm includes a third MOSFET and a fourth MOSFET. The source S of the third MOSFET is electrically connected to the drain D of the fourth MOSFET. The negative terminal of the inductor Lm2 is electrically connected to the source S of the third MOSFET and the drain D of the fourth MOSFET, respectively. The slow-speed rectifier bridge arm includes a fifth MOSFET and a sixth MOSFET. The source (S) of the fifth MOSFET is electrically connected to the drain (D) of the sixth MOSFET. The AC power supply... The negative terminal is electrically connected to the source S of the fifth MOSFET and the drain D of the sixth MOSFET, respectively. The drain D of the first MOSFET, the drain D of the third MOSFET, the drain D of the fifth MOSFET, the positive terminal of the output filter capacitor C, the positive terminal of the load resistor R, and the positive terminal of the voltage output V are electrically connected to each other. The source S of the second MOSFET, the source S of the fourth MOSFET, the source S of the sixth MOSFET, the negative terminal of the output filter capacitor C, the negative terminal of the load resistor R, and the negative terminal of the voltage output V are electrically connected to each other. The method is characterized by the following steps: A. Power on the bridgeless totem pole type PFC power supply; B. Set the voltage boost slope, and the output voltage will increase from zero. C. Determine the voltage regulation status of the output voltage. If it is over-voltage or under-voltage, return to step B to modify the voltage boost slope and re-determine the voltage regulation status until the output voltage is determined to be regulated. D. After the output voltage is determined to be regulated, it is determined whether the output voltage value has reached the standard value. If it has not reached the standard value, the voltage will continue to be increased until the output voltage reaches the standard value. Once the output voltage value reaches the standard value, the start-up phase ends and the working phase begins. E. Determine the working range and use different control algorithms for the three stages: use the normal working algorithm under normal working conditions; use the positive-negative algorithm when the AC voltage changes from the positive half-cycle to the negative half-cycle; use the negative-positive algorithm when the AC voltage changes from the negative half-cycle to the positive half-cycle. F. Complete the algorithm calculation and output the corresponding control quantity; G. Perform the corresponding driving action according to the control quantity; H. Determine whether the driving action obtained in step G is a shutdown action. If it is, execute the shutdown action; otherwise, return to step E to continue the judgment of the working area.

2. The control method according to claim 1, characterized in that: The normal working algorithm used in step E under normal working conditions includes the following steps: E11. The inductor current in the bridgeless totem pole type PFC power supply circuit for the wireless charging system is respectively... AC voltage and output voltage The sampled values ​​are then processed and transformed before being input into the control loop; E12. The output voltage Compare with the target value and obtain the output voltage error. The output is then fed into the voltage loop PI for proportional-integral calculation to obtain the control quantity of the output voltage; E13. The voltage loop PI output control quantity is fed into the multiplier, and the corresponding multiplication operation is performed to obtain the control quantity of the target power value; E14. The control quantity of the target power value and the AC voltage. The values ​​after proportional calculation are multiplied to calculate the control quantity of the inductor current and perform phase detection at the same time. E15. After multiplication phase detection, the control quantity of the inductor current is obtained, and the inductor current is... The sampled values ​​are compared, and then the current loop PI is used for PI calculation, finally obtaining the output control quantity of the current loop PI. E16. PWM is generated based on the output control quantity of the final current loop PI to obtain the corresponding high-speed bridge arm drive signal; E17. The slow-speed transistor operates in normal mode based on the aforementioned AC voltage. The positive and negative values ​​are used for driving, in the AC voltage When the value is positive, Q1 of the fifth MOSFET is off and Q2 of the sixth MOSFET is on. When the AC voltage Vac is negative, Q1 of the fifth MOSFET is on and Q2 of the sixth MOSFET is off.

3. The control method according to claim 1, characterized in that: The positive-negative algorithm used in step E during the transition of AC voltage from the negative half-cycle to the positive half-cycle includes the following steps: E21. The inductor current in the bridgeless totem pole type PFC power supply circuit for the wireless charging system is respectively... AC voltage and output voltage The sampled values ​​are then processed and transformed before being input into the control loop; E22. The output voltage Compare with the target value and obtain the output voltage error. The output is then fed into the voltage loop PI for proportional-integral calculation to obtain the control quantity of the output voltage; E23. The voltage loop PI output control quantity is fed into the multiplier, and the corresponding multiplication operation is performed to obtain the control quantity of the target power value; E24. The bottom loop generates a triangular ramp with a positive slope. The triangular ramp controls three parameters: ramp slope, ramp time, and ramp enable, and generates a corresponding triangular ramp. E25. By using a multiplier, the positive triangular ramp signal and the calculated power value are superimposed to obtain a calculated power value that varies according to the ramp ratio. E26. The control signal after the superposition of ramps drives the first high-speed power bridge arm and the second high-speed power bridge arm, but only gives the drive signal to the second MOSFET and the Q3 of the fourth MOSFET, that is, the lower transistor of the two high-speed power bridge arms. E27. The drive signal of the first MOSFET and the Q4 of the third MOSFET remains at 0, that is, there is no drive level; E28. The slow rectifier bridge arm is in the dead zone at this time, and the drive signals of the fifth MOSFET and the sixth MOSFET are both 0, that is, there is no drive level.

4. The control method for a bridgeless totem pole type PFC power supply for a wireless charging system according to claim 1, characterized in that: The negative-positive algorithm used in step E during the transition of AC voltage from the negative half-cycle to the positive half-cycle includes the following steps: E31. The inductor current in the bridgeless totem pole type PFC power supply circuit for the wireless charging system is respectively... AC voltage and output voltage The sampled values ​​are then processed and transformed before being input into the control loop; E32. The output voltage Compare with the target value and obtain the output voltage error. The output is then fed into the voltage loop PI for proportional-integral calculation to obtain the control quantity of the output voltage; E33. The voltage loop PI output control quantity is fed into the multiplier, and the corresponding multiplication operation is performed to obtain the control quantity of the target power value; E34. The bottom loop generates a triangular ramp with a positive slope. The triangular ramp controls three parameters: ramp slope, ramp time, and ramp enable, and generates a corresponding triangular ramp. E35. By using a multiplier, the positive triangular ramp signal and the calculated power value are superimposed to obtain a calculated power value that varies according to the ramp ratio. E36. The control quantity after the superposition of ramps is used to drive the first high-speed power bridge arm and the second high-speed power bridge arm, but only the drive signal is given to the Q4 of the first MOSFET and the third MOSFET, that is, the upper transistor of the two high-speed power bridge arms. E37. The drive signals of the second MOSFET of the high-speed power bridge arm and the Q3 of the fourth MOSFET are kept at 0, that is, there is no drive level; E38. The slow rectifier bridge arm is in the dead zone at this time, and the drive signals of the fifth MOSFET and the sixth MOSFET are both 0, that is, there is no drive level.

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