Control methods for bridgeless rectifiers, bridgeless rectifiers and wireless charging systems

Abstract

This invention relates to the field of rectifier circuit control technology, specifically to a control method for a bridgeless rectifier, a bridgeless rectifier, and a wireless charging system, comprising: Step S1: acquiring the load power at the load end, and adjusting the output power of the bridgeless rectifier according to the load power; Step S2: generating the current operating efficiency of the bridgeless rectifier based on the output power and the input power of the bridgeless rectifier, and adjusting the operating frequency of the bridgeless rectifier according to the operating efficiency until the operating efficiency is maximized, thereby completing the operating frequency adjustment under the current load power. The beneficial effects of this invention are: by reducing the operating frequencies of the first and second switching transistors in the bridgeless rectifier, while achieving voltage regulation and effective output power adjustment, the requirements for sampling circuits and control frequencies of the bridgeless rectifier are reduced, thereby reducing the overall production and design costs of the bridgeless rectifier.

Description

Technical Field

[0001] This invention relates to the field of rectifier circuit control technology, specifically to a control method for a bridgeless rectifier, a bridgeless rectifier, and a wireless charging system. Background Technology

[0002] Bridgeless rectifier refers to a rectifier based on... Figure 1 The uncontrolled rectifier shown and such Figure 2 The rectifier shown is an improved version of the fully controlled rectifier. Compared to... Figure 1 The uncontrolled rectifier shown consists of four diodes and Figure 2 The bridgeless rectifier uses only two switching transistors, while the fully controlled rectifier uses four switching transistors. This achieves better voltage control than the uncontrolled rectifier, while reducing the need to control the switching transistors.

[0003] In the prior art, there are already relevant technical solutions for applying bridgeless rectifiers in power supply systems. However, in the actual implementation process, the inventors found that the control methods of bridgeless rectifiers in the prior art, such as those in references [1] and [2], both mention that a switching frequency with the same frequency as the input current is required to achieve voltage regulation control of the bridgeless rectifier during the control process. However, since the frequency of the input current of the bridgeless rectifier is usually high, a high operating frequency needs to be designed in the control process of the bridgeless rectifier based on the above methods, which in turn puts forward higher design requirements on the sampling and calculation circuit of the bridgeless rectifier, increases the design and manufacturing cost, and is not conducive to reducing the power consumption of the bridgeless rectifier.

[0004] [1]Jaeho Cha. Modeling and Control of Double-Sided LCC CompensationTopology with Semi-Bridgeless Active Rectifier for Inductive Power TransferSystem[J]. Energies,2019

[0005] [2]Deshang Sha. A High-Efficiency Current-Fed Semi-Dual-Active BridgeDC–DC Converter for Low Input Voltage Applications[J]. IEEE Transactions on Industrial Electronics, 2016 Summary of the Invention

[0006] To address the aforementioned problems in the existing technology, a control method for a bridgeless rectifier, a bridgeless rectifier, and a wireless charging system are provided.

[0007] The specific technical solution is as follows:

[0008] A control method for a bridgeless rectifier, the bridgeless rectifier including a first switching transistor and a second switching transistor, both the first switching transistor and the second switching transistor being located in the lower bridge arm of the bridgeless rectifier, the control method comprising:

[0009] Step S1: Obtain the load power at the load end, and adjust the output power of the bridgeless rectifier according to the load power;

[0010] Step S2: Calculate the current operating efficiency of the bridgeless rectifier based on the output power and the input power of the bridgeless rectifier, and adjust the operating frequency of the bridgeless rectifier according to the operating efficiency until the operating efficiency is maximized, so as to complete the operating frequency adjustment under the current load power.

[0011] The operating frequency includes the operating frequency of the first switching transistor and the operating frequency of the second switching transistor.

[0012] Preferably, step S1 includes:

[0013] Step S11: Obtain the load power and the current output power of the bridgeless rectifier;

[0014] Step S12: Adjust the duty cycle of the first switch and the second switch according to the load power and the current output power to obtain the output power corresponding to the load power.

[0015] Preferably, in step S12, the duty cycle of the first switch and the duty cycle of the second switch are adjusted using a proportional-integral-derivative method.

[0016] Preferably, before step S1, the input current frequency of the bridgeless rectifier is obtained as the operating frequency of the bridgeless rectifier in its initial state, then step S2 includes:

[0017] Step S21: Generate and store the current operating efficiency of the bridgeless rectifier based on the output power and the input power of the bridgeless rectifier;

[0018] Step S22: Reduce the operating frequency, and then acquire and store the new operating efficiency corresponding to the operating frequency;

[0019] Step S23: Repeat step S22 to obtain multiple work efficiencies, compare the multiple work efficiencies, and obtain and output the work frequency with the highest work efficiency;

[0020] Step S24: Adjust the operating frequency of the bridgeless rectifier to the operating frequency with the highest operating efficiency to complete the operating frequency adjustment under the current load power.

[0021] Preferably, in step S22, the method for reducing the operating frequency is as follows:

[0022] ;

[0023] in, The operating frequency, The input current frequency is n, which is a set of pre-generated frequency reduction parameters.

[0024] Preferably, the range of the frequency reduction parameter is: , where n is the frequency reduction parameter.

[0025] Preferably, the control method further includes:

[0026] Obtain the current direction and input voltage of the input current;

[0027] When the input current is a positive current and the amplitude of the input voltage is zero, the fourth switch is turned on, which can realize the soft turn-on of the fourth switch and prevent the rectifier input voltage distortion.

[0028] When the input current is a reverse current and the amplitude of the input voltage is zero, the second switch is turned on, which can realize the soft turn-on of the second switch and prevent the rectifier input voltage distortion.

[0029] Preferably, the control method further includes:

[0030] Step S3: Obtain the new load power, and adjust the duty cycle of the first switch and the second switch at the current operating frequency to generate output power corresponding to the load power.

[0031] A bridgeless rectifier, comprising:

[0032] The first switching transistor has its drain connected to the positive input terminal of the bridgeless rectifier;

[0033] The source of the first switching transistor is connected to the negative output terminal of the bridgeless rectifier, and the base of the first switching transistor is connected to the first control terminal of a controller.

[0034] A first diode, the anode of which is connected to the positive input terminal, and the cathode of which is connected to the positive output terminal of the bridgeless rectifier;

[0035] The drain of the second switching transistor is connected to the negative input terminal of the bridgeless rectifier;

[0036] The source of the second switching transistor is connected to the negative output terminal, and the base of the second switching transistor is connected to the second control terminal of the controller;

[0037] The second diode has its anode connected to the negative input terminal and its cathode connected to the positive output terminal.

[0038] The controller includes a memory and a processor, and the memory stores computer instructions;

[0039] When the processor executes the computer instructions, the controller performs the control method described above.

[0040] A wireless charging system, comprising:

[0041] The first rectifier is connected to an external AC power supply.

[0042] An inverter, the input of which is connected to the output of the first rectifier;

[0043] A first compensation network, the input of which is connected to the output of the inverter;

[0044] A transmission coil, the input end of which is connected to the output end of the first compensation network;

[0045] A receiving coil, which is coupled to the transmitting coil;

[0046] A second compensation network, the input of which is connected to the output of the receiving coil;

[0047] A second rectifier, the input of which is connected to the output of the second compensation network, and the output of which is connected to an external electrical appliance;

[0048] The first rectifier and the second rectifier are rectifier modules of the same type;

[0049] The rectifier module includes a memory and a processor, wherein the memory stores computer instructions;

[0050] When the processor executes the computer instructions, the rectifier module performs the control method described above.

[0051] The above technical solution has the following advantages or beneficial effects: by reducing the operating frequency of the first switching transistor and the second switching transistor in the bridgeless rectifier, the requirements of the bridgeless rectifier for sampling circuit and control frequency are reduced while achieving voltage regulation and effective adjustment of output power, thereby reducing the overall production and design cost of the bridgeless rectifier. Attached Figure Description

[0052] Embodiments of the invention will be described more fully with reference to the accompanying drawings. However, the drawings are for illustration and explanation only and do not constitute a limitation on the scope of the invention.

[0053] Figure 1 This is a schematic diagram of an uncontrolled rectifier in the prior art;

[0054] Figure 2 This is a schematic diagram of a fully controlled rectifier in the prior art;

[0055] Figure 3 This is a schematic diagram of a semi-controlled rectifier in an embodiment of the present invention;

[0056] Figure 4 This is a schematic diagram of a control method in an embodiment of the present invention;

[0057] Figure 5 This is a waveform diagram of the control scheme in one embodiment of the present invention;

[0058] Figure 6 This is a waveform diagram of the control scheme in another embodiment of the present invention;

[0059] Figure 7 This is a schematic diagram of sub-step S1 in an embodiment of the present invention;

[0060] Figure 8 This is a schematic diagram of sub-step S2 in an embodiment of the present invention;

[0061] Figure 9 This is a schematic diagram of voltage distortion in an embodiment of the present invention;

[0062] Figure 10 This is a schematic diagram of another control method in an embodiment of the present invention;

[0063] Figure 11 This is a schematic diagram of voltage and duty cycle in an embodiment of the present invention;

[0064] Figure 12 This is a schematic diagram of a semi-controlled rectifier in an embodiment of the present invention;

[0065] Figure 13 This is a schematic diagram of a wireless power transmission system in an embodiment of the present invention. Detailed Implementation

[0066] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0067] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0068] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0069] This invention includes:

[0070] A control method for a bridgeless rectifier, applicable to... Figure 3 The bridgeless rectifier shown includes a first switching transistor D2 and a second switching transistor D4. Both the first switching transistor D2 and the second switching transistor D4 are located in the lower bridge arm of the bridgeless rectifier. Figure 4 As shown, the control methods include:

[0071] Step S1: Obtain the load power at the load end and adjust the output power of the bridgeless rectifier according to the load power;

[0072] Step S2: Calculate the current operating efficiency of the bridgeless rectifier based on the output power and the input power of the bridgeless rectifier, and adjust the operating frequency of the bridgeless rectifier according to the operating efficiency until the operating efficiency is maximized, so as to complete the operating frequency adjustment under the current load power.

[0073] The operating frequency includes the operating frequency of the first switching transistor D2 and the operating frequency of the second switching transistor D4.

[0074] Specifically, to address the issue that existing technologies for controlling bridgeless rectifiers require setting the operating frequencies of the first switch D2 and the second switch D4 to the same frequency as the input current, resulting in high cost and power consumption, the inventors adjusted the operating frequencies of the first switch D2 and the second switch during implementation.

[0075] In one embodiment, the inventors, for a bridgeless rectifier with an input current frequency of 85.5 kHz, set the operating frequencies of the first switching transistor D2 and the second switching transistor to 8550 Hz, and formed the following... Figure 5 , Figure 6 The control scheme shown.

[0076] in, Figure 5In the control scheme shown, the duty cycle of both the first switch D2 and the second switch D4 is 50%, and the switching signals of the first switch D2 and the second switch D4 are complementary. The output waveform is as follows: Figure 4 In At this time, at the input voltage The waveform contains a two-level envelope at 8550 Hz with an amplitude of 110V.

[0077] Figure 6 In the control scheme shown, the duty cycle of both the first switch D2 and the second switch D4 is 80%. At this time, there is a phenomenon where two switches are simultaneously conducting in the bridgeless rectifier circuit, and its output waveform is as follows. Figure 5 In At this time, at the input voltage The waveform has an 8550 Hz three-level envelope with an amplitude of 140V and a zero-level point.

[0078] Based on the above phenomena, the inventors discovered that when the circuit state at the load end changes, the equivalent impedance at the output side of the inverter at the transmitter end changes, thereby causing a change in the system's output power. Based on this principle, the inventors achieved power regulation of the rectifier by setting a lower operating frequency, thus avoiding the problem in the prior art of requiring high-frequency control and sampling circuits for the bridgeless rectifier.

[0079] In a preferred embodiment, such as Figure 7 As shown, step S1 includes:

[0080] Step S11: Obtain the load power and the current output power of the bridgeless rectifier;

[0081] Step S12: Adjust the duty cycle of the first switch D2 and the second switch D4 according to the load power and the current output power to obtain the output power corresponding to the load power.

[0082] Specifically, in order to achieve power control of the bridgeless rectifier, this embodiment obtains the load power at the load end and the current output power of the bridgeless rectifier, and adjusts the output power of the bridgeless rectifier by controlling the duty cycle of the first switch D2 and the second switch D4.

[0083] In a preferred embodiment, in step S12, the duty cycle of the first switch and the duty cycle of the second switch are adjusted using a proportional-integral-differential method.

[0084] In a preferred embodiment, before step S1, the input current frequency of the bridgeless rectifier is obtained as the operating frequency of the bridgeless rectifier in its initial state, then as follows: Figure 8 As shown, step S2 includes:

[0085] Step S21: Generate and store the current operating efficiency of the bridgeless rectifier based on the output power and the input power of the bridgeless rectifier;

[0086] Step S22: Reduce the operating frequency, then acquire and store the new operating efficiency corresponding to the operating frequency;

[0087] Step S23: Repeat step S22 to obtain multiple work efficiencies, compare the multiple work efficiencies, and obtain and output the work frequency with the highest work efficiency;

[0088] Step S24: Adjust the operating frequency of the bridgeless rectifier to the operating frequency with the highest operating efficiency to complete the operating frequency adjustment under the current load power.

[0089] In a preferred embodiment, in step S22, the method for reducing the operating frequency is as follows:

[0090] ;

[0091] in, For operating frequency, Where n is the input current frequency, and n is a set of pre-generated frequency reduction parameters.

[0092] In a preferred embodiment, the frequency reduction parameter ranges from [value missing]. , where n is the frequency reduction parameter.

[0093] In a preferred embodiment, the control method further includes:

[0094] Obtain the current direction and input voltage of the input current;

[0095] When the input current is positive and the amplitude of the input voltage is zero, the second switch D4 is turned on, which can realize the soft turn-on of the second switch D4 and prevent the rectifier input voltage distortion.

[0096] When the input current is a reverse current and the amplitude of the input voltage is zero, the second switch D4 is turned on, which can realize the soft turn-on of the second switch D4 and prevent the rectifier input voltage distortion.

[0097] Specifically, such as Figure 9 As shown, since voltage distortion occurs when the first switch D2 and the second switch D4 switch, this embodiment avoids voltage distortion by setting a specific switch to be turned on under specific operating conditions, thereby improving the power supply stability of the bridgeless rectifier.

[0098] In a preferred embodiment, such as Figure 10 As shown, the control method also includes:

[0099] Step S3: Obtain the new load power, and adjust the duty cycle of the first and second switching transistors at the current operating frequency to generate output power corresponding to the load power.

[0100] Specifically, in the process of reducing the operating frequency of the first switching transistor D2 and the second switching transistor D4, the inventors discovered that, as Figure 11 As shown, when the frequency reduction parameter is small, such as 2, adjusting the duty cycle to further change the output power results in a small voltage change. Therefore, by reducing the operating frequency of the first switch S1 and the second switch S2, only the duty cycle needs to be adjusted to change the output power, thus achieving a lower operating frequency and better power control.

[0101] A bridgeless rectifier, such as Figure 12 As shown, it includes:

[0102] The drain of the first switching transistor X2 is connected to the positive input terminal of the bridgeless rectifier.

[0103] The source of the first switching transistor X2 is connected to the negative output terminal of the bridgeless rectifier, and the base of the first switching transistor X2 is connected to the first control terminal of a controller U1.

[0104] The first diode X1 has its anode connected to the positive input terminal and its cathode connected to the positive output terminal of the bridgeless rectifier.

[0105] The drain of the second switching transistor X4 is connected to the negative input terminal of the bridgeless rectifier.

[0106] The source of the second switch X4 is connected to the negative output terminal, and the base of the second switch X4 is connected to the second control terminal of the controller.

[0107] The anode of the second diode X3 is connected to the negative input terminal, and the cathode of the second diode X3 is connected to the positive output terminal.

[0108] The controller U1 includes a memory U11 and a processor U12. The memory U11 stores computer instructions.

[0109] When the processor U12 executes computer instructions, the controller U1 performs the control method described above.

[0110] Specifically, addressing the issue that existing bridgeless rectifiers require high-frequency sampling and control circuits, this embodiment achieves control of the bridgeless rectifier at lower frequencies by setting controller U1 to execute the aforementioned control method, thereby reducing the overall manufacturing cost and design specifications of the bridgeless rectifier.

[0111] During implementation,

[0112] A wireless charging system, such as Figure 12 As shown, it includes:

[0113] First rectifier 1, first rectifier 1 is connected to an external AC power supply terminal;

[0114] Inverter 2, the input terminal of inverter 2 is connected to the output terminal of the first rectifier 1;

[0115] The first compensation network 3 has its input connected to the output of the inverter 2.

[0116] Transmission coil 4, the input end of which is connected to the output end of the first compensation network 3;

[0117] The receiving coil 5 is coupled to the transmitting coil 4.

[0118] The second compensation network 6 has its input terminal connected to the output terminal of the receiving coil 5;

[0119] The second rectifier 7 has its input terminal connected to the output terminal of the second compensation network 6, and its output terminal connected to an external electrical appliance 8.

[0120] The first rectifier 1 and the second rectifier 7 are the same type of rectifier module;

[0121] Taking the first rectifier 1 as an example, the rectifier module of the first rectifier 1 includes a memory 11 and a processor 12, and the memory 11 stores computer instructions.

[0122] When processor 12 executes computer instructions, it performs the control method described above.

[0123] Specifically, in the existing technology, wireless charging systems using bridgeless rectifiers require costly sampling and control circuits for the bridgeless rectifiers. This embodiment eliminates the need for costly high-frequency sampling and control circuits in the existing technology by selecting a specific bridgeless rectifier module and using the above-mentioned control method to control the bridgeless rectifier, thereby effectively reducing the overall cost of the wireless charging system.

[0124] The beneficial effects of this invention are as follows: by reducing the operating frequency of the first switching transistor and the second switching transistor in the bridgeless rectifier, the requirements of the bridgeless rectifier for sampling circuits and control frequency are reduced while achieving voltage regulation and effective adjustment of output power, thereby reducing the overall production and design cost of the bridgeless rectifier.

[0125] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A control method of a bridgeless rectifier, characterized by, The bridgeless rectifier includes a first switching transistor and a second switching transistor, both of which are located in the lower bridge arm of the bridgeless rectifier. The control method includes: Step S1: Obtain the load power at the load end, and adjust the output power of the bridgeless rectifier according to the load power until the output power matches the load power; Step S2: Calculate the current operating efficiency of the bridgeless rectifier based on the output power and the input power of the bridgeless rectifier, and adjust the operating frequency of the bridgeless rectifier according to the operating efficiency until the operating efficiency is maximized, so as to complete the operating frequency adjustment. The operating frequency includes the operating frequency of the first switching transistor and the operating frequency of the second switching transistor; Before step S1, if the input current frequency of the bridgeless rectifier is obtained as the operating frequency of the bridgeless rectifier in its initial state, then step S2 includes: Step S21: Generate and store the current operating efficiency of the bridgeless rectifier based on the output power and the input power of the bridgeless rectifier; Step S22: Reduce the operating frequency, and then acquire and store the new operating efficiency corresponding to the operating frequency; Step S23: Repeat step S22 to obtain multiple work efficiencies, compare the multiple work efficiencies, and obtain and output the work frequency with the highest work efficiency; Step S24: Adjust the operating frequency of the bridgeless rectifier to the operating frequency with the highest operating efficiency to complete the adjustment of the operating frequency.

2. The control method according to claim 1, characterized by, Step S1 includes: Step S11: Obtain the load power and the current output power of the bridgeless rectifier; Step S12: Adjust the duty cycle of the first switch and the second switch according to the load power and the current output power to obtain the output power corresponding to the load power.

3. The control method according to claim 2, characterized by, The control method further includes: Step S3: Obtain the new load power, and adjust the duty cycle of the first switch and the second switch at the current operating frequency to generate the output power corresponding to the load power.

4. The control method according to claim 2, characterized by, In step S12, the duty cycle of the first switch and the duty cycle of the second switch are adjusted using the proportional-integral-derivative method.

5. The control method according to claim 1, characterized by, In step S22, the method for reducing the operating frequency is as follows: ； wherein, is the operating frequency, is the input current frequency, and n is a set of pre-generated frequency reduction parameters.

6. The control method according to claim 5, characterized in that, The frequency reduction parameter n has a value in the range , n is the frequency reduction parameter.

7. A bridgeless rectifier characterized by, include: The first switching transistor has its drain connected to the positive input terminal of the bridgeless rectifier; The source of the first switching transistor is connected to the negative output terminal of the bridgeless rectifier, and the base of the first switching transistor is connected to the first control terminal of a controller. A first diode, the anode of which is connected to the positive input terminal, and the cathode of which is connected to the positive output terminal of the bridgeless rectifier; The drain of the second switching transistor is connected to the negative input terminal of the bridgeless rectifier; The source of the second switching transistor is connected to the negative output terminal, and the base of the second switching transistor is connected to the second control terminal of the controller; The second diode has its anode connected to the negative input terminal and its cathode connected to the positive output terminal. The controller includes a memory and a processor, and the memory stores computer instructions; When the processor executes the computer instructions, the controller performs the control method as described in any one of claims 1-6.

8. A wireless charging system, characterized in that, include: The first rectifier is connected to an external AC power supply. An inverter, the input of which is connected to the output of the first rectifier; A first compensation network, the input of which is connected to the output of the inverter; A transmission coil, the input end of which is connected to the output end of the first compensation network; A receiving coil, which is coupled to the transmitting coil; A second compensation network, the input of which is connected to the output of the receiving coil; A second rectifier, the input of which is connected to the output of the second compensation network, and the output of which is connected to an external electrical appliance; The first rectifier and the second rectifier are rectifier modules of the same type; The rectifier module includes a memory and a processor, wherein the memory stores computer instructions; When the processor executes the computer instructions, the rectifier module performs the control method as described in any one of claims 1-6.

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