Phase-shift control method and device of wireless power transmission system and wireless electrical appliance

Abstract

The application discloses a phase-shifting control method and device of a wireless power transmission system and wireless electrical equipment, the wireless power transmission system comprising a wireless transmitting module for wirelessly transmitting electric energy, and a wireless receiving module for wirelessly receiving electric energy, the wireless transmitting module comprising a full-bridge inverter circuit, and the wireless receiving module being connected with a load, the method comprising: acquiring a target input inductance curve under a target load resistance value, wherein the input inductance curve is used for representing the corresponding relationship between the working frequency of the wireless power transmission system and the input inductance value; determining the target input inductance value and the target working frequency corresponding to the target input inductance value based on the target input inductance curve, wherein the target input inductance value makes the wireless power transmission system inductive; and adjusting the working frequency of the wireless power transmission system to the target working frequency and performing phase-shifting control, so that the switching device of the full-bridge inverter circuit performs soft switching. The above scheme effectively reduces the loss of the wireless power transmission system.

Description

Technical Field

[0001] This invention belongs to the field of wireless power transmission, and particularly relates to a phase-shifting control method, device and wireless electrical equipment for a wireless power transmission system. Background Technology

[0002] Wireless power transmission systems are typically divided into a transmitting side and a receiving side. The transmitting side transmits electrical energy wirelessly, while the receiving side receives the transmitted energy to power electrical equipment. In related technologies, to ensure a stable output voltage, voltage regulation is usually required. Voltage regulation methods in wireless power transmission systems include frequency conversion control and phase-shift control. Frequency conversion control adjusts the output voltage by changing the operating frequency, while phase-shift control is a fixed-frequency control that adjusts the proportion of the square wave voltage output by the inverter circuit in the wireless power transmission system to regulate the output voltage.

[0003] However, when using frequency conversion control for voltage regulation, the wide range of operating frequency changes leads to low transmission efficiency of the wireless power transmission system. When using phase shift control for voltage regulation, the switching devices in the inverter circuit cannot achieve zero-voltage turn-on, resulting in increased losses. Summary of the Invention

[0004] The present invention aims to solve, at least to some extent, the technical problems of low transmission efficiency and high loss in the voltage regulation process of wireless power transmission systems in related technologies, and provides a phase shift control method, device and wireless electrical equipment for wireless power transmission systems.

[0005] In a first aspect, embodiments of the present invention provide a phase-shift control method for a wireless power transmission system. The wireless power transmission system includes a wireless transmitting module for wirelessly transmitting electrical energy and a wireless receiving module for wirelessly receiving electrical energy. The wireless transmitting module includes a full-bridge inverter circuit, and the wireless receiving module is connected to a load. The method includes:

[0006] Obtain the target input reactance curve under the target load resistance value, wherein the input reactance curve is used to characterize the correspondence between the operating frequency of the wireless power transmission system and the input reactance value;

[0007] Based on the target input reactance curve, the target input reactance value and the target operating frequency corresponding to the target input reactance value are determined, wherein the target input reactance value makes the wireless power transmission system inductive;

[0008] The operating frequency of the wireless power transmission system is adjusted to the target operating frequency and phase-shift control is performed to enable soft switching of the switching devices in the full-bridge inverter circuit.

[0009] In some implementations, obtaining the target input inductive reactance curve under the target load resistance includes:

[0010] Obtain N input inductive reactance curves for N load resistance values, where N is an integer greater than 1;

[0011] For each input reactance curve, determine the maximum reactance value of each input reactance curve within the preset operating frequency range, and obtain a total of N maximum reactance values;

[0012] From the N maximum inductive reactance values, M maximum inductive reactance values ​​that satisfy a preset range are determined, and the inductive reactance curve corresponding to the minimum value among the M maximum inductive reactance values ​​is taken as the target input inductive reactance curve, wherein the lower limit of the preset range of inductive reactance values ​​is greater than 0, and M is a positive integer.

[0013] In some implementations, determining the target input reactance value and the target operating frequency corresponding to the target input reactance value based on the target input reactance curve includes:

[0014] The maximum inductive reactance of the target input reactance curve within a preset operating frequency range is determined as the target input reactance value;

[0015] Based on the target input reactance curve, the target operating frequency corresponding to the target input reactance value is determined.

[0016] In some implementations, the method further includes:

[0017] Determine the resonant frequency of the wireless power transmission system;

[0018] Based on the resonant frequency, the preset operating frequency is determined, wherein the upper limit of the preset operating frequency is less than the resonant frequency.

[0019] In some implementations, adjusting the operating frequency of the wireless power transmission system to the target operating frequency and performing phase-shift control includes:

[0020] Adjust the operating frequency of the wireless power transmission system to the target operating frequency;

[0021] Obtain the actual output voltage and target output voltage of the wireless receiving module;

[0022] Based on the voltage difference between the actual output voltage and the target output voltage, the target phase shift angle of the lagging arm relative to the leading arm in the full-bridge inverter circuit is determined, and based on the target phase shift angle, the switching devices in the full-bridge inverter circuit are controlled to open and close.

[0023] In some implementations, determining the target phase shift angle of the lagging arm relative to the leading arm in the full-bridge inverter circuit based on the voltage difference between the actual output voltage and the target output voltage includes:

[0024] The target phase shift angle is obtained by performing proportional-integral control on the voltage difference.

[0025] Secondly, embodiments of the present invention provide a phase-shifting control device for a wireless power transmission system. The wireless power transmission system includes a wireless transmitting module for wirelessly transmitting electrical energy and a wireless receiving module for wirelessly receiving electrical energy. The wireless transmitting module includes a full-bridge inverter circuit, and the wireless receiving module is connected to a load. The device includes:

[0026] The acquisition module is used to acquire the target input reactance curve under the target load resistance value, wherein the input reactance curve is used to characterize the correspondence between the operating frequency of the wireless power transmission system and the input reactance value;

[0027] The processing module is used to determine the target input inductive reactance value and the target operating frequency corresponding to the target input inductive reactance value based on the target input inductive reactance curve, wherein the target input inductive reactance value makes the wireless power transmission system inductive;

[0028] The adjustment module is used to adjust the operating frequency of the wireless power transmission system to the target operating frequency and perform phase shift control so that the switching devices of the full-bridge inverter circuit can be soft-switched.

[0029] Thirdly, embodiments of the present invention provide a wireless electrical device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method described in any embodiment of the first aspect.

[0030] In some implementations, the wireless electrical equipment is a wireless air conditioning unit.

[0031] Fourthly, embodiments of the present invention provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method provided in the first aspect.

[0032] One or more technical solutions provided in the embodiments of the present invention achieve at least the following technical effects or advantages:

[0033] The control method for the wireless power transmission system provided in the embodiments of this specification includes a wireless transmitting module for transmitting electrical energy and a wireless receiving module for wirelessly receiving electrical energy. The wireless transmitting module includes a full-bridge inverter circuit, and the wireless receiving module is connected to the load. When performing phase-shift control on the wireless power transmission system, a target input inductive reactance curve is obtained under a target load resistance value. This input inductive reactance curve characterizes the correspondence between the operating frequency of the wireless power transmission system and the input inductive reactance value. Based on the target input inductive reactance curve, a target input inductive reactance value and a target operating frequency corresponding to that value are determined. The target input inductive reactance value makes the wireless power transmission system inductive. The operating frequency of the wireless power transmission system is adjusted to the target operating frequency, and phase-shift control is performed to soft-switch the switching devices of the full-bridge inverter circuit. The scheme in the embodiments of this specification adjusts the operating frequency of the wireless power transmission system to the target operating frequency, making the wireless power transmission system inductive. Since the voltage will lead the current in an inductive circuit, for the switching devices of the full-bridge inverter circuit, the voltage across the switching device will drop to zero before the switching device is turned on, so that there is no crossover time between the voltage and current changes across the switching device, thereby reducing the loss of the switching device. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 A flowchart of a phase-shifting control method for a wireless power transmission system according to an embodiment of the present invention is shown;

[0036] Figure 2 A circuit structure diagram of a wireless power transmission system according to an embodiment of the present invention is shown;

[0037] Figure 3 This diagram illustrates N input inductive reactance curves corresponding to N load resistance values ​​in an embodiment of the present invention.

[0038] Figure 4 The figure shows a simulated voltage waveform of the wireless power transmission system operating at the resonant frequency in an embodiment of the present invention.

[0039] Figure 5 The figure shows a simulated voltage waveform of the wireless power transmission system operating at the target operating frequency in an embodiment of the present invention.

[0040] Figure 6A schematic diagram of a phase-shifting control device for a wireless power transmission system according to an embodiment of the present invention is shown;

[0041] Figure 7 A schematic diagram of a wireless electrical device according to an embodiment of the present invention is shown. Detailed Implementation

[0042] In view of the technical problem of large losses when regulating voltage in wireless power transmission systems through phase-shift control in related technologies, this specification provides a phase-shift control method, device and wireless electrical equipment for wireless power transmission systems. By adjusting the operating frequency of the wireless power transmission system to the target operating frequency, the wireless power transmission system becomes inductive. The voltage of the switching devices in the full-bridge inverter circuit can drop to zero before being turned on, so that there is no crossover time between the voltage and current changes across the switching devices, thereby reducing the losses of the switching devices.

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0044] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0045] The phase-shifting control method for a wireless power transmission system provided by the present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0046] like Figure 1 The diagram shown is a flowchart of a phase-shifting control method for a wireless power transmission system provided in an embodiment of this specification. The method includes the following steps:

[0047] Step S101: Obtain the target input reactance curve under the target load resistance value, wherein the input reactance curve is used to characterize the correspondence between the operating frequency of the wireless power transmission system and the input reactance value;

[0048] Step S102: Based on the target input reactance curve, determine the target input reactance value and the target operating frequency corresponding to the target input reactance value, wherein the target input reactance value makes the wireless power transmission system inductive;

[0049] Step S103: Adjust the operating frequency of the wireless power transmission system to the target operating frequency and perform phase shift control so that the switching devices of the full-bridge inverter circuit can be soft-switched.

[0050] The methods provided in the embodiments of this specification can be applied to wireless power transmission systems, which can be installed in electrical appliances, such as wireless air conditioners and wireless air purifiers that include wireless power transmission systems.

[0051] It should be noted that the wireless power transmission system includes a wireless transmitting module and a wireless receiving module. The wireless transmitting module is used to wirelessly transmit electrical energy, and the wireless receiving module is used to receive the electrical energy transmitted by the wireless transmitting module and output a stable voltage or current signal.

[0052] To facilitate understanding, a specific circuit structure of a wireless power transmission system is described below. For example... Figure 2 As shown, the wireless transmission module of this wireless power transmission system may include a DC power supply, a full-bridge inverter circuit, and a transmitter compensation capacitor C. T Transmitting coil L T Internal resistance R of the transmitting coil T The full-bridge inverter circuit consists of four MOSFETs (Q1, Q2, Q3, Q4); the wireless receiver module of the wireless power transmission system may include a receiving coil L. R The internal resistance R of the receiving coil R Receiver compensation capacitor C R rectifier circuit, electrolytic capacitor and load R L The rectifier circuit can be selected according to actual needs; for example, a full-bridge rectifier circuit can be used.

[0053] Figure 2 In the wireless power transmission system, the wireless transmitting module can convert DC power to AC power through a full-bridge inverter circuit, and then transmit the AC power through the transmitting end compensation capacitor C. T From transmitting coil L T It transmits wirelessly outwards. The wireless receiver module can transmit wirelessly via a receiving coil L. R The AC power transmitted by the wireless transmitter module is received and then passes through the compensation capacitor C at the receiver end. RThe alternating current (AC) is transmitted to the rectifier circuit, which converts the AC to direct current (DC) to supply the load R. L Provides electrical energy.

[0054] Of course, the circuit structure of a wireless power transmission system can be adjusted and modified according to actual needs, and no limitation is made here. To facilitate the description of the voltage control method provided in the embodiments of this specification, the following will use... Figure 2 We will use the circuit structure in the example to illustrate this.

[0055] In step S101, the target load resistance value can be one of multiple load resistance values ​​corresponding to the wireless power transmission system. Taking a wireless air conditioner as an example, the load resistance value corresponding to the wireless air conditioner operating in dehumidification mode may be different from the load resistance value corresponding to the wireless air conditioner operating in cooling mode. When determining the target load resistance value, the load resistance values ​​of the wireless air conditioner under various operating states can be determined first, and then the target load resistance value can be determined from them. The target load resistance value can also be a pre-set load resistance value. For example, in order to simulate the voltage regulation of the wireless power transmission system, multiple load resistance values ​​can be pre-set, and the target load resistance value can be one of them.

[0056] In the embodiments described in this specification, different load resistance values ​​correspond to different input inductive reactance curves. The input inductive reactance curve characterizes the relationship between the operating frequency of the wireless power transmission system and the input inductive reactance value. In practical implementation, the input inductive reactance value can be calculated using the following formula:

[0057]

[0058] Among them, X in ω is the input inductive reactance, L is the operating frequency of the wireless power transmission system, and ω is the input inductive reactance. T L is the self-inductance of the transmitting coil. R For the self-inductance of the receiving coil, C T For the transmitter compensation capacitor, C R R is the compensation capacitor for the receiving end. R R is the internal resistance of the receiving coil. L R is the load resistance, and M is the mutual inductance between the transmitting and receiving coils. From the above formula, we can see that R... L Different, X in The input impedance curves between ω and ω are also different.

[0059] In this embodiment of the specification, multiple input inductive reactance curves under different load resistance values ​​can be predetermined. Then, the target input inductive reactance curve under the target load resistance value can be selected from the multiple input inductive reactance curves. Specifically, step S101 can be achieved through the following steps: obtaining N input inductive reactance curves under N load resistance values, where N is an integer greater than 1; for each input inductive reactance curve, determining the maximum inductive reactance value of each input inductive reactance curve within a preset operating frequency range, obtaining a total of N maximum inductive reactance values; determining M maximum inductive reactance values ​​that satisfy the preset inductive reactance value range from the N maximum inductive reactance values, and taking the inductive reactance curve corresponding to the minimum value among the M maximum inductive reactance values ​​as the target input inductive reactance curve, wherein the lower limit of the preset inductive reactance value range is greater than 0, and M is a positive integer.

[0060] Specifically, the N load resistance values ​​can be multiple load resistance values ​​that the wireless power transmission system can actually connect to, or they can be multiple preset load resistance values; there is no limitation here. For example... Figure 3 The figure shows a schematic diagram of N input inductive reactance curves corresponding to N load resistance values, where N is 7 and the load resistance values ​​are 2Ω, 4Ω, 6Ω...14Ω respectively. Figure 3 In the diagram, the vertical axis represents the imaginary part of the input impedance, which corresponds to the input inductive reactance. The horizontal axis represents the normalized frequency, which is equal to the actual operating frequency divided by the resonant frequency.

[0061] Furthermore, for each input reactance curve, the maximum reactance value within a preset operating frequency range is determined. This preset operating frequency range can be set according to actual needs. In this embodiment, considering that the coil transmission efficiency is higher the operating frequency is closer to the resonant frequency and lower the operating frequency is farther from the resonant frequency, the preset operating frequency range can be selected near the resonant frequency to improve the coil transmission efficiency.

[0062] In one embodiment, the preset operating frequency range can be determined by: determining the resonant frequency of the wireless power transmission system; and determining the preset operating frequency based on the resonant frequency, wherein the upper limit of the preset operating frequency is less than the resonant frequency. For example, the preset operating frequency can be a range less than the resonant frequency, or a lower limit and / or an upper limit of the preset operating frequency can be set. For example, the upper limit can be an operating frequency that differs from the resonant frequency by a first threshold, and the difference between the upper limit and the lower limit can be a second threshold, wherein the first threshold and the second threshold can be limited according to actual needs.

[0063] The preset frequency range in the embodiments of this specification is: Figure 3The frequency range corresponding to region ①. The process of determining region ① can be as follows: determine the input inductive reactance curve with the minimum load resistance, determine two points with zero input inductive reactance within the range below the resonant frequency, and then take the operating frequencies corresponding to these two points as the upper and lower limits of the preset operating frequency range.

[0064] For each input inductive reactance curve, the maximum inductive reactance value in region ① is determined, resulting in N maximum inductive reactance values. It should be noted that for switching devices such as MOSFETs and IGBTs, the voltage across their terminals is 0 when they are on, and the voltage across their terminals is the input voltage when they are off. When the switching device switches from the off state to the on state, the voltage across its terminals must drop from the input voltage to 0, while the current rises from 0 to the steady-state current. If there is an overlap between the rise and fall times of voltage and current, then the product of voltage and current will not be zero during this overlap time, resulting in losses. Zero-voltage switching means that the voltage across the switching device has already dropped to 0 before it is turned on. In this way, there is no overlap time between voltage and current, thus reducing losses. Therefore, to achieve zero-voltage switching, the voltage can act before the current. The characteristic of an inductor is that the voltage leads the current. The role of an inductor in a circuit is inductive reactance. Therefore, the larger the inductive reactance value, the more the voltage can lead the current, and the easier it is to achieve zero-voltage switching, i.e., soft switching. Therefore, in order to achieve soft switching of the switching device, the embodiments of this specification can set the operating frequency of the wireless power transmission system at the frequency corresponding to the maximum inductive reactance. However, the frequency corresponding to the maximum inductive reactance will shift under different load resistance values. Therefore, it is necessary to further filter out the target operating frequency from multiple frequencies corresponding to the maximum inductive reactance.

[0065] Because the inductive reactance decreases with increasing load resistance within a range below the resonant frequency, and the larger the load resistance, the more difficult it is to achieve zero-voltage switching of the switching device. Therefore, in this embodiment, the operating frequency corresponding to a larger load resistance can be selected as the target operating frequency to enable soft switching even with a larger load resistance. Specifically, firstly, M maximum inductive reactance values ​​(M is a positive integer) that satisfy a preset inductive reactance range are determined from N maximum inductive reactance values. Since the circuit is not inductive when the inductive reactance is 0, soft switching of the switching device cannot be achieved. Therefore, the preset inductive reactance range can be selected as a range where the inductive reactance is greater than 0. Of course, the preset inductive reactance range can also be set as needed, for example, the lower limit of the preset inductive reactance range is greater than 5Ω, 8Ω, etc. Further, the input inductive reactance curve corresponding to the minimum value among the M maximum inductive reactance values ​​is taken as the target input inductive reactance curve, and the load resistance corresponding to this inductive reactance curve is taken as the target load resistance.

[0066] like Figure 3As shown, taking a preset inductive reactance range greater than 0 as an example, since the maximum inductive reactance of the input inductive reactance curve corresponding to a load resistance of 12Ω in region ① is 0, and the maximum inductive reactance of the input inductive reactance curve corresponding to a load resistance of 10Ω in region ① is greater than 0, and the maximum inductive reactance corresponding to other load resistances less than 10Ω is greater than the maximum inductive reactance when the load resistance is 10Ω, therefore, 10Ω can be used as the target load resistance, and the input inductive reactance curve corresponding to 10Ω can be used as the target input inductive reactance curve.

[0067] Further, in step S102, after determining the target input reactance curve, the target input reactance value and the target operating frequency corresponding to the target input reactance value are determined based on the target input reactance curve. The target input reactance value is the reactance value that makes the wireless power transmission system inductive. In one embodiment, target S102 can be achieved through the following steps: determining the maximum reactance value of the target input reactance curve within a preset operating frequency range as the target input reactance value; and determining the target operating frequency corresponding to the target input reactance value based on the target input reactance curve.

[0068] Specifically, as described above, the closer the operating frequency is to the resonant frequency, the higher the coil's transmission efficiency and the larger the input inductive reactance, which is more conducive to achieving zero-voltage switching of the switching device. Therefore, in the embodiments of this specification, the maximum inductive reactance within a preset operating frequency range can be used as the target input inductive reactance value, and its corresponding operating frequency can be used as the target operating frequency. The determination of the preset operating frequency range has already been described above and will not be repeated here.

[0069] In step S103, the operating frequency of the wireless power transmission system is adjusted to the target operating frequency, and phase shift control is performed on the wireless power transmission system to output a stable voltage.

[0070] The operating frequency of the wireless power transmission system can be the switching frequency of the switching devices in the full-bridge inverter circuit. By controlling the switching frequency of the switching devices, the output AC frequency of the full-bridge inverter circuit can be adjusted, enabling soft switching of the switching devices at the target operating frequency. Simultaneously, to achieve a stable output voltage, phase-shift control is applied to the wireless power transmission system, setting the phase shift angle between the lagging arm and the leading arm of the full-bridge inverter circuit. For example... Figure 2 As shown, the leading arms in the full-bridge inverter circuit are Q1 and Q2, and the lagging arms are Q3 and Q4. The phase shift angle of the lagging arm relative to the leading arm in the full-bridge inverter circuit can be the angle by which Q4 lags behind Q1 in conduction.

[0071] Phase-shift control of a wireless power transmission system can be achieved by: adjusting the operating frequency of the wireless power transmission system to the target operating frequency; obtaining the actual output voltage and the target output voltage of the wireless receiving module; determining the target phase shift angle of the lagging arm relative to the leading arm in the full-bridge inverter circuit based on the voltage difference between the actual output voltage and the target output voltage; and controlling the switching of the switching devices in the full-bridge inverter circuit based on the target phase shift angle.

[0072] Specifically, the actual output voltage of the wireless receiver module can be obtained by detecting the voltage across the load, such as... Figure 2 As shown, the actual output voltage can be the load resistance R. L The voltage at both ends. The target output voltage of the wireless receiver module can be the desired output voltage. The target output voltage can be adjusted and set according to actual needs, and is not limited here.

[0073] In order to output a stable voltage, the actual output voltage needs to be stable near the target output voltage. In the embodiments of this specification, the target phase shift angle can be obtained by performing proportional-integral control on the voltage difference between the actual output voltage and the target output voltage.

[0074] Specifically, proportional-integral (PI) control can be used to control the voltage difference. This PI control circuit can be located at either the receiver or the transmitter. Taking the transmitter as an example, the PI control circuit can be integrated within the wireless transmission module or used as a separate circuit. In practice, when the actual output voltage is higher than the target output voltage, the voltage difference is accumulated in the positive direction using PI control and added to the current phase shift angle to obtain the new phase shift angle, i.e., the target phase shift angle. When the actual output voltage is lower than the target output voltage, the voltage difference is accumulated in the negative direction using PI control and the accumulated amount is subtracted from the current phase shift angle to obtain the new phase shift angle, i.e., the target phase shift angle.

[0075] Furthermore, the phase shift angle of the lagging arm relative to the leading arm in the full-bridge inverter circuit is set as the target phase shift angle to stabilize the actual output voltage near the target output voltage.

[0076] To better illustrate the control method provided in the embodiments of this specification, the operation of the wireless power transmission system is simulated using the following system parameters as an example, wherein the input voltage U of the DC power supply is... in =311V, mutual inductance M between transmitting and receiving coils = 21uH, compensation capacitor C at transmitting end T =31.349nF, self-inductance of transmitting coil L T=60uH, receiving coil self-inductance L R =60uH, internal resistance R of transmitting coil T =0.05Ω, receiving end compensation capacitor C T =31.349nF, internal resistance R of the receiving coil R =0.05Ω, the resonant frequency of the wireless power transmission system is 116kHz, the target load resistance is 10Ω, and in the input reactance curve corresponding to the target load resistance, the target frequency corresponding to the maximum reactance within the preset operating frequency range is 110kHz.

[0077] like Figure 4 The figure shows the simulated voltage waveform of the wireless power transmission system operating at a resonant frequency of 116kHz. Figure 4 Figure A shows the simulated voltage waveforms of the source-drain voltage (VDS) and drive voltage (VGS) of the lagging arm switching device. Figure B shows the actual output voltage waveforms of the wireless power transmission system, where VO represents the actual output voltage. Figure C shows the target phase shift angle between the lagging arm and the leading arm in the full-bridge inverter circuit, with VGS1 being the drive voltage waveform of the leading arm switching device and VGS4 being the drive voltage waveform of the lagging arm switching device. Specifically, from... Figure 4 As can be seen from Figure A, VDS did not drop to 0 before VGS changed from low to high, and there was a crossover between the two, so the zero-voltage turn-on of the hysteresis arm was not achieved.

[0078] like Figure 5 The figure shows the simulated voltage waveform of the wireless power transmission system operating at the target operating frequency of 110kHz. Figure 5 Figure A shows the simulated voltage waveforms of the source-drain voltage (VDS) and drive voltage (VGS) of the lagging arm switching device; Figure B shows the actual output voltage waveforms of the wireless power transmission system; Figure C shows the target phase shift angle between the lagging arm and the leading arm in the full-bridge inverter circuit; VGS1 is the drive voltage waveform of the leading arm switching device; and VGS4 is the drive voltage waveform of the lagging arm switching device. Specifically, from... Figure 5 As can be seen from Figure A, VDS has dropped to 0 before VGS changes from low to high, achieving zero-voltage turn-on of the hysteresis arm.

[0079] In summary, the solution in the embodiments of this specification sets the operating frequency of the wireless power transmission system to the target operating frequency corresponding to the maximum inductive reactance. Since the target operating frequency is close to the resonant frequency, the transmission efficiency can be effectively improved. At the same time, since the wireless power transmission system is inductive at the target operating frequency, zero-voltage conduction of the switching devices can be effectively achieved.

[0080] Based on the same inventive concept, embodiments of this specification provide a phase-shifting control device for a wireless power transmission system. The wireless power transmission system includes a wireless transmitting module for wirelessly transmitting electrical energy and a wireless receiving module for wirelessly receiving electrical energy. The wireless transmitting module includes a full-bridge inverter circuit, and the wireless receiving module is connected to a load, such as... Figure 6 The device includes:

[0081] The acquisition module 601 is used to acquire the target input reactance curve under the target load resistance value, wherein the input reactance curve is used to characterize the correspondence between the operating frequency of the wireless power transmission system and the input reactance value;

[0082] Processing module 602 is used to determine a target input inductive reactance value and a target operating frequency corresponding to the target input inductive reactance value based on the target input inductive reactance curve, wherein the target input inductive reactance value makes the wireless power transmission system inductive;

[0083] The adjustment module 603 is used to adjust the operating frequency of the wireless power transmission system to the target operating frequency and perform phase shift control so that the switching devices of the full-bridge inverter circuit can be soft-switched.

[0084] In some implementations, the acquisition module 601 is used for:

[0085] Obtain N input inductive reactance curves for N load resistance values, where N is an integer greater than 1;

[0086] For each input reactance curve, determine the maximum reactance value of each input reactance curve within the preset operating frequency range, and obtain a total of N maximum reactance values;

[0087] From the N maximum inductive reactance values, M maximum inductive reactance values ​​that satisfy a preset range are determined, and the inductive reactance curve corresponding to the minimum value among the M maximum inductive reactance values ​​is taken as the target input inductive reactance curve, wherein the lower limit of the preset range of inductive reactance values ​​is greater than 0, and M is a positive integer.

[0088] In some implementations, the processing module 602 is used for:

[0089] The maximum inductive reactance of the target input reactance curve within a preset operating frequency range is determined as the target input reactance value;

[0090] Based on the target input reactance curve, the target operating frequency corresponding to the target input reactance value is determined.

[0091] In some embodiments, the apparatus further includes:

[0092] The first determining module is used to determine the resonant frequency of the wireless power transmission system;

[0093] The second determining module is used to determine the preset operating frequency based on the resonant frequency, wherein the upper limit of the preset operating frequency is less than the resonant frequency.

[0094] In some implementations, the adjustment module 603 is used for:

[0095] Adjust the operating frequency of the wireless power transmission system to the target operating frequency;

[0096] Obtain the actual output voltage and target output voltage of the wireless receiving module;

[0097] Based on the voltage difference between the actual output voltage and the target output voltage, the target phase shift angle of the lagging arm relative to the leading arm in the full-bridge inverter circuit is determined, and based on the target phase shift angle, the switching devices in the full-bridge inverter circuit are controlled to open and close.

[0098] In some implementations, the adjustment module 603 is used for:

[0099] The target phase shift angle is obtained by performing proportional-integral control on the voltage difference.

[0100] Regarding the above-mentioned device, the specific functions of each module have been described in detail in the embodiments of the phase-shifting control method of the wireless power transmission system provided in this specification, and will not be elaborated here.

[0101] This invention provides a wireless electrical device, such as... Figure 7 As shown, the device includes a memory 704, a processor 702, and a computer program stored in the memory 704 and executable on the processor 702. When the processor 702 executes the program, it implements the aforementioned phase-shift control method for a wireless power transmission system. This electrical device can be a wireless air conditioning unit or other equipment equipped with a wireless power transmission system.

[0102] Among them, Figure 7In this document, a bus architecture (represented by bus 700) is used. Bus 700 may include any number of interconnected buses and bridges, linking various circuits including one or more processors represented by processor 702 and memory represented by memory 704. Bus 700 may also link various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further herein. Bus interface 707 provides an interface between bus 700 and receiver 701 and transmitter 703. Receiver 701 and transmitter 703 may be the same element, i.e., a transceiver, providing a unit for communicating with various other devices over a transmission medium. Processor 702 is responsible for managing bus 700 and general processing, while memory 704 can be used to store data used by processor 702 during operation.

[0103] The functions described herein can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions can be stored as one or more instructions or codes on or transmitted via a computer-readable medium. Other examples and embodiments are within the scope and spirit of this invention and the appended claims. For example, due to the nature of software, the functions described above can be implemented using software executed by a processor, hardware, firmware, hardwired, or any combination thereof. Furthermore, the functional units can be integrated into a single processing unit, or each unit can exist physically separately, or two or more units can be integrated into a single unit.

[0104] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0105] The units described as separate components may or may not be physically separate. Similarly, the components of the control device may or may not be physical units; they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0106] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0107] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A phase-shifting control method for a wireless power transmission system, characterized in that, The wireless power transmission system includes a wireless transmitting module for wirelessly transmitting electrical energy and a wireless receiving module for wirelessly receiving electrical energy. The wireless transmitting module includes a full-bridge inverter circuit, and the wireless receiving module is connected to a load. The method includes: Obtain the target input reactance curve under the target load resistance value, wherein the input reactance curve is used to characterize the correspondence between the operating frequency of the wireless power transmission system and the input reactance value; Based on the target input reactance curve, the target input reactance value and the target operating frequency corresponding to the target input reactance value are determined, wherein the target input reactance value makes the wireless power transmission system inductive; Adjusting the operating frequency of the wireless power transmission system to the target operating frequency and performing phase shift control to enable soft switching of the switching devices in the full-bridge inverter circuit includes: adjusting the operating frequency of the wireless power transmission system to the target operating frequency; acquiring the actual output voltage and the target output voltage of the wireless receiving module; determining the target phase shift angle of the lagging arm relative to the leading arm in the full-bridge inverter circuit based on the voltage difference between the actual output voltage and the target output voltage; and controlling the switching on and off of the switching devices in the full-bridge inverter circuit based on the target phase shift angle.

2. The method as described in claim 1, characterized in that, The process of obtaining the target input inductive reactance curve under the target load resistance includes: Obtain N input inductive reactance curves for N load resistance values, where N is an integer greater than 1; For each input reactance curve, determine the maximum reactance value of each input reactance curve within the preset operating frequency range, and obtain a total of N maximum reactance values; From the N maximum inductive reactance values, M maximum inductive reactance values ​​that satisfy a preset range are determined, and the inductive reactance curve corresponding to the minimum value among the M maximum inductive reactance values ​​is taken as the target input inductive reactance curve, wherein the lower limit of the preset range of inductive reactance values ​​is greater than 0, and M is a positive integer.

3. The method as described in claim 1, characterized in that, The step of determining the target input reactance value and the target operating frequency corresponding to the target input reactance value based on the target input reactance curve includes: The maximum inductive reactance of the target input reactance curve within a preset operating frequency range is determined as the target input reactance value; Based on the target input reactance curve, the target operating frequency corresponding to the target input reactance value is determined.

4. The method as described in claim 2 or 3, characterized in that, The method further includes: Determine the resonant frequency of the wireless power transmission system; Based on the resonant frequency, the preset operating frequency is determined, wherein the upper limit of the preset operating frequency is less than the resonant frequency.

5. The method as described in claim 1, characterized in that, Determining the target phase shift angle of the lagging arm relative to the leading arm in the full-bridge inverter circuit based on the voltage difference between the actual output voltage and the target output voltage includes: The target phase shift angle is obtained by performing proportional-integral control on the voltage difference.

6. A phase-shifting control device for a wireless power transmission system, characterized in that, The wireless power transmission system includes a wireless transmitting module for wirelessly transmitting electrical energy and a wireless receiving module for wirelessly receiving electrical energy. The wireless transmitting module includes a full-bridge inverter circuit, and the wireless receiving module is connected to a load. The device includes: The acquisition module is used to acquire the target input reactance curve under the target load resistance value, wherein the input reactance curve is used to characterize the correspondence between the operating frequency of the wireless power transmission system and the input reactance value; The processing module is used to determine the target input inductive reactance value and the target operating frequency corresponding to the target input inductive reactance value based on the target input inductive reactance curve, wherein the target input inductive reactance value makes the wireless power transmission system inductive; An adjustment module is used to adjust the operating frequency of the wireless power transmission system to the target operating frequency and perform phase shift control to enable soft switching of the switching devices in the full-bridge inverter circuit. The module includes: adjusting the operating frequency of the wireless power transmission system to the target operating frequency; acquiring the actual output voltage and the target output voltage of the wireless receiving module; determining the target phase shift angle of the lagging arm relative to the leading arm in the full-bridge inverter circuit based on the voltage difference between the actual output voltage and the target output voltage; and controlling the switching on / off of the switching devices in the full-bridge inverter circuit based on the target phase shift angle.

7. A wireless electrical device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the program, implements the method of any one of claims 1-5.

8. The wireless electrical device as claimed in claim 7, characterized in that, The wireless electrical equipment is a wireless air conditioning unit.

9. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed by a processor, implements the steps of the method according to any one of claims 1-5.

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