Wireless power transfer system and control system and control method

Abstract

The present disclosure relates to the field of power electronics, in particular to a wireless power transmission system, a control system and a control method. The wireless power transmission system comprises a transmitting end and a receiving end. The transmitting end comprises an input power supply group, an inverter circuit and an LCC network, which are connected in sequence. The receiving end comprises an LLC network, a rectifier circuit and an output load group, which are connected in sequence. The LLC network comprises a receiving coil, a compensation inductor and a first compensation capacitor. The receiving coil and the transmitting coil in the LCC network are oppositely arranged. The receiving coil and the first compensation capacitor satisfy a resonance condition. The present disclosure can improve the output voltage control range of the wireless power transmission system at low cost and improve the control accuracy.

Description

Technical Field

[0001] This disclosure relates to the field of power electronics technology, and in particular to a wireless power transmission system, control system, and control method. Background Technology

[0002] Wireless power transfer technology can achieve mechanical isolation between power generation and power consumption equipment, reduce the use of sockets and cables, and has broad application prospects in fields such as rail transportation and railway freight train power supply systems. In particular, in demand scenarios with a large voltage variation range, wireless power transfer systems need to have a large output voltage range.

[0003] Among related technologies, the most widely used technical solutions for secondary-side controlled LCC-S wireless power transfer systems are: cascading an additional DC-DC converter into the system to regulate the output voltage; or introducing a wireless communication system into the system for phase-shift frequency modulation control.

[0004] However, the output voltage regulation scheme provided in the related technologies by adding a DC-DC converter increases the system size, which not only leads to high control costs for the wireless power transfer converter, but also reduces power density. On the other hand, the output voltage regulation scheme based on the wireless communication system requires communication between the transmitter and receiver inside the wireless power transfer system, which can lead to bit errors and / or regulation delays. Summary of the Invention

[0005] This disclosure provides a wireless power transfer system, control system, and control method that can improve the output voltage control range of the wireless power transfer system at low cost and enhance control accuracy.

[0006] In a first aspect, this disclosure provides a wireless power transmission system, comprising:

[0007] The transmitter includes an input power supply, an inverter circuit, and an LCC network, which are connected in sequence.

[0008] The receiving end includes an LLC network, a rectifier circuit, and an output load group, which are connected in sequence. The LLC network includes a receiving coil, a compensation inductor, and a first compensation capacitor. The receiving coil and the transmitting coil in the LLC network are arranged opposite to each other, and the receiving coil and the first compensation capacitor satisfy the resonance condition.

[0009] In some embodiments, the receiving coil, the compensation inductor, and the first compensation capacitor are connected in series.

[0010] In some embodiments, the rectifier circuit includes a first switch, a second switch, a third switch, and a fourth switch, wherein the first switch and the second switch are connected in series to form a first bridge arm, the third switch and the fourth switch are connected in series to form a second bridge arm, the first bridge arm and the second bridge arm are connected in parallel, the first compensation capacitor is connected in the first bridge arm at a first common node between the first switch and the second switch, the receiving coil is connected in the second bridge arm at a second common node between the third switch and the fourth switch.

[0011] In some embodiments, the output load group includes a load capacitor and an output load, wherein the load capacitor and the output load are connected in parallel.

[0012] In some embodiments, the LCC network includes a transmitting coil, a second compensation capacitor, a third compensation capacitor, and a resonant inductor, wherein the transmitting coil, the second compensation capacitor, and the resonant inductor are connected in series, and the third compensation capacitor is connected in parallel with the series circuit of the transmitting coil and the second compensation capacitor.

[0013] In some embodiments, the inverter circuit includes a fifth switch, a sixth switch, a seventh switch, and an eighth switch, wherein the fifth switch and the sixth switch are connected in series to form a third bridge arm, the seventh switch and the eighth switch are connected in series to form a fourth bridge arm, the third bridge arm and the fourth bridge arm are connected in parallel, the resonant inductor is connected in the third bridge arm at a third common node between the fifth switch and the sixth switch, and the third compensation capacitor and the transmitting coil are connected in the fourth bridge arm at a fourth common node between the seventh switch and the eighth switch.

[0014] In some embodiments, the input power supply group includes an input voltage source and an input capacitor, wherein the input voltage source and the input capacitor are connected in parallel.

[0015] In a second aspect, this disclosure provides a control system for a wireless power transmission system, the control system being used to control the wireless power transmission system as described in the first aspect, comprising:

[0016] The bridge phase shift angle calculator is used to obtain the current target output voltage and acquire the voltage across the current rectifier bridge. Based on the first voltage relationship between the voltage across the rectifier bridge and the target output voltage and the bridge phase shift angle, the target bridge phase shift angle is determined and sent to the pulse width modulation (PWM) controller.

[0017] The adder / subtractor is used to acquire the fundamental component of the equivalent total input voltage at the receiving end and the fundamental component of the voltage across the current rectifier bridge, determine the difference between the fundamental component of the equivalent total input voltage at the receiving end and the fundamental component of the voltage across the current rectifier bridge, obtain the current fundamental component difference, and send the current fundamental component difference to the proportional-integral processor.

[0018] A proportional-integral processor is used to process the difference of the fundamental component of the current voltage based on proportional-integral calculations to obtain the current inter-bridge phase shift angle, and send the current inter-bridge phase shift angle to the PWM controller;

[0019] The PWM controller is used to determine the pulse control signal of the switching transistor in the rectifier circuit based on the target bridge phase shift angle and the current bridge phase shift angle. When it is determined that the output voltage of the output load is not the target output voltage, the controller repeatedly instructs the adder and subtractor and the proportional-integral processor to determine the updated bridge phase shift angle and performs the process of determining the updated pulse control signal of the switching transistor in the rectifier circuit based on the target bridge phase shift angle and the updated bridge phase shift angle, until the output voltage of the output load is the target output voltage.

[0020] Thirdly, this disclosure provides a control method for a wireless power transmission system, the method being applied in a control system of the wireless power transmission system as described in the second aspect, comprising:

[0021] Obtain the current target output voltage;

[0022] Based on the current target output voltage, the current voltage across the rectifier bridge, and the first voltage relationship between the voltage across the rectifier bridge and the target output voltage and the phase shift angle within the bridge, the target phase shift angle within the bridge is determined.

[0023] Based on the fundamental component of the equivalent total input voltage at the receiving end, and the fundamental components of the voltages at both ends of the current rectifier bridge, the current inter-bridge phase shift angle is determined;

[0024] Based on the target bridge phase shift angle and the current bridge phase shift angle, the load output voltage is adjusted. If the load output voltage is not the target output voltage, the process of determining the updated bridge phase shift angle and adjusting the output load output voltage is repeated until the output load output voltage is the target output voltage.

[0025] In some embodiments, the method further includes:

[0026] The equivalent load of the receiver is determined based on the load value of the receiver and the phase shift angle within the target bridge, as well as the correlation between the equivalent load of the receiver and the load value and the phase shift angle within the bridge.

[0027] Based on the equivalent total input voltage at the receiving end, the current voltage across the rectifier bridge, and the second voltage relationship between the system reactive power and the equivalent total input voltage at the receiving end, the voltage across the rectifier bridge, and the phase shift angle between the bridges, the minimum reactive power of the system is determined when the output voltage of the output load is the target output voltage.

[0028] This disclosure provides a wireless power transmission system, control system, and control method. By connecting a compensating inductor in series at the receiver of an LCC / S resonant network, the receiver transmits power based on the LLC network. The LLC network can be equivalent to a receiving coil in resonance state connected in series with a compensating inductor. This facilitates a dual phase-shift control strategy at the receiver, enabling the adjustment of the output voltage and the control of reactive power of the wireless power transmission system without additional equipment. This increases the output voltage control range of the wireless power transmission system and facilitates the reduction of reactive power, thereby improving the system's power density. Furthermore, the system achieves output voltage adjustment and reactive power control without the need for wireless communication between the transmitter and receiver, improving the control accuracy of the wireless power transmission system.

[0029] 1. Technical Features: The receiving end includes an LLC network, a rectifier circuit, and an output load group. The LLC network includes a receiving coil, a compensation inductor, and a first compensation capacitor. The receiving coil and the first compensation capacitor satisfy the resonance condition. The technical effect is to solve the problems of high wireless power transmission costs or poor system adjustment accuracy caused by the need to cascade an additional DC-DC converter (DC / DC converter) in the system or introduce a wireless communication system for phase-shift frequency modulation control. Attached Figure Description

[0030] The present disclosure will be described in more detail below based on embodiments and with reference to the accompanying drawings:

[0031] Figure 1 This is a schematic diagram of the circuit structure of a wireless power transmission system provided in an embodiment of the present disclosure.

[0032] Figure 2 This is a schematic diagram of the circuit structure of a controlled source model of a wireless power transmission system provided in an embodiment of this disclosure.

[0033] Figure 3 An equivalent circuit diagram of a receiver compensation network provided in an embodiment of this disclosure.

[0034] Figure 4 This is a schematic diagram of the control system of a wireless power transmission system provided in an embodiment of the present disclosure.

[0035] Figure 5This is a schematic diagram of the pulse control signal for a switching transistor in a rectifier circuit, provided as an embodiment of the present disclosure.

[0036] Figure 6 A flowchart of a control method for a wireless power transmission system provided in an embodiment of this disclosure.

[0037] In the accompanying drawings, the same parts are referred to by the same reference numerals, and the drawings are not drawn to scale. Detailed Implementation

[0038] To enable those skilled in the art to better understand the technical solutions of this disclosure, and to fully understand and implement the process of how this disclosure applies technical means to solve technical problems and achieve corresponding technical effects, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, not all embodiments. The embodiments of this disclosure and the various features within them can be combined with each other without conflict, and the resulting technical solutions are all within the protection scope of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort should fall within the protection scope of this disclosure.

[0039] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this disclosure 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 this disclosure 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 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.

[0040] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0041] Example 1

[0042] Figure 1 A wireless power transmission system provided in this disclosure embodiment, such as Figure 1 As shown, the wireless power transmission system includes:

[0043] The transmitter 101 and receiver 102 are provided. The transmitter 101 includes an input power supply, an inverter circuit, and an LCC network, which are connected in sequence.

[0044] The receiver 102 includes an LLC network, a rectifier circuit, and an output load group, which are connected in sequence. The LLC network includes a receiving coil L. 2f Compensating inductor L f2e and the first compensation capacitor C 2e The receiving coil L 2f The receiving coil L is positioned opposite to the transmitting coil L1 in the LCC network. 2f and the first compensation capacitor C 2e The resonance condition is met.

[0045] Optional, such as Figure 1 As shown, in the transmitter 101, the LCC network includes a transmitter coil L1, a second compensation capacitor C1, and a third compensation capacitor C f1 and resonant inductance L f1 Among them, the transmitting coil L1, the second compensation capacitor C1 and the resonant inductor L f1 The third compensation capacitor C is connected in series. f1 It is connected in parallel with the series circuit of the transmitting coil L1 and the second compensation capacitor C1.

[0046] The inverter circuit includes a fifth switch T1, a sixth switch T2, a seventh switch T3, and an eighth switch T4. The fifth switch T1 and the sixth switch T2 are connected in series to form the third bridge arm, and the seventh switch T3 and the eighth switch T4 are connected in series to form the fourth bridge arm. The resonant inductor L... f1 The third compensation capacitor C is connected in the third bridge arm, at the third common node between the fifth switch T1 and the sixth switch T2. f1 The transmitting coil L1 is connected to the fourth common node in the fourth bridge arm between the seventh switch T3 and the eighth switch T4.

[0047] The input power supply group includes an input voltage source U1 and an input capacitor C. d1 Wherein, the input voltage source U1 and the input capacitor C d1 in parallel.

[0048] It should be noted that at the transmitting end, U AB Switching transistors for inverter circuits T 1- T4. Input voltage source U 1. Output voltage of the inverter circuit after conversion.

[0049] Please continue to refer to this. Figure 1 At receiver 102, the receiving coil L in the LLC network 2f Compensating inductor L f2e and the first compensation capacitor C 2e Connected in series.

[0050] The rectifier circuit includes a first switch T5, a second switch T6, a third switch T7, and a fourth switch T8. The first switch T5 and the second switch T6 are connected in series to form a first bridge arm, and the third switch T7 and the fourth switch T8 are connected in series to form a second bridge arm. The first bridge arm and the second bridge arm are connected in parallel. The first compensation capacitor C... 2e The receiving coil L is connected in the first bridge arm to the first common node between the first switch T1 and the second switch T2. 2f It is connected in the second bridge arm to the second common node between the third switch T7 and the fourth switch T8.

[0051] The output load group includes a load capacitor and an output load, wherein the load capacitor C R and the output load R L in parallel.

[0052] It should be noted that, in the embodiments disclosed herein, U ab The voltage across the rectifier bridge is the voltage induced in the receiving coil. U ab Through the switching transistor T 5- T 8. Transfer energy to the load R L Its output voltage is U 2.

[0053] In the wireless power transmission system provided in this embodiment, under resonant conditions, the voltage excitation angular frequency satisfies:

[0054] ;(Formula 1)

[0055] In Formula 1, f The switching frequency is given, where L2 is the total receiving coil at the receiving end, and the size of the total receiving coil is equal to the receiving coil L. 2f and compensation inductor L f2e The sum of, i.e., L 2= L 2f +L f2e .

[0056] Among them, the voltage and current of the receiving end and the transmitting end are related to the mutual inductance. M The relation is:

[0057] ;(Formula 2)

[0058] In Formula 2, This is the first equivalent output voltage of the transmitting end. This is the second equivalent input voltage at the receiving end. The equivalent current at the transmitting end, This is the equivalent current at the receiving end.

[0059] Furthermore, ignoring the series equivalent resistance of the resonant components in the resonant compensation network, and by equivalently replacing the mutual inductance model with the controlled source model, the controlled source model of the wireless power transfer system is obtained as follows: Figure 2 ,in, U is the second equivalent output voltage of the transmitter. L2 Given the second equivalent input voltage at the receiving end, Kirchhoff's voltage law equation at the transmitting end is:

[0060] (Formula 3)

[0061] In Formula 3, For the current in loop 1, This is the current in loop 2, i.e., the current in the transmitting coil.

[0062] Kirchhoff's voltage law equation at the receiving end is:

[0063] (Formula 4)

[0064] In Formula 4, U is the current in the receiving circuit. c2 U is the equivalent total input voltage at the receiving end, where U c2 The value is the voltage across the first compensation capacitor ( U c2e ) and the voltage across the receiving coil ( U L2f ) and.

[0065] Furthermore, based on the above formulas 3 and 4, the receiver compensation network under resonance conditions can be equivalent to... Figure 3 At system resonance, the current in the transmitting coil... and inverter circuit output voltage U AB They are directly proportional; if the output voltage U of the inverter circuit... AB If the current in the coil is constant, then... If the voltage is constant, then the equivalent total input voltage U at the receiving end is... c2 Constant, meaning the equivalent input voltage across the receiving coil at the receiver is a constant voltage source; therefore, two control degrees of freedom can be introduced for the wireless power transfer system: the inter-bridge phase shift angle α and the intra-bridge phase shift angle β, by maintaining the voltage U across the rectifier bridge. ab The fundamental amplitude is constant. By controlling the inter-bridge phase shift angle and the intra-bridge phase shift angle, the output voltage of the output load is adjusted, thereby reducing the reactive power of the system. In the wireless power transmission system, the first voltage relationship between the voltage across the rectifier bridge and the output voltage and the intra-bridge phase shift angle β is:

[0066] ;(Formula 5)

[0067] The second voltage relationship between the system reactive power and the equivalent total input voltage at the receiving end, the voltage across the rectifier bridge, and the phase shift angle between the bridges is as follows:

[0068] ;(Formula 6)

[0069] In Equation 6, P represents the reactive power at the system receiver. The equivalent load at the receiving end is related to the load value and the phase shift angle within the bridge as follows:

[0070] ;(Formula 7)

[0071] In summary, the wireless power transmission system provided in this disclosure enables power transmission based on the LLC network by connecting a compensation inductor in series at the receiver of the LCC / S resonant network. The LLC network can be equivalent to a receiving coil in resonance connected in series with a compensation inductor, facilitating the use of a dual phase-shift control strategy at the receiver. This allows for voltage regulation and reactive power control of the wireless power transmission system without additional equipment, increasing the output voltage control range and reducing reactive power, thereby improving the system's power density. Furthermore, the system achieves voltage regulation and reactive power control without the need for wireless communication between the transmitter and receiver, enhancing the control accuracy of the wireless power transmission system.

[0072] Example 2

[0073] This disclosure provides a control system for a wireless power transmission system, which is used to control the wireless power transmission system as described in the above embodiments, such as... Figure 4As shown, the control system of the wireless power transmission system includes an in-bridge phase shift angle calculator 401, a pulse width modulation (PWM) controller 402, an adder / subtractor 403, and a proportional-integral processor 404, wherein...

[0074] Bridge phase shift angle calculator 401 is used to obtain the current target output voltage. U 2ref And collect the current voltage U across the rectifier bridge. ab And, based on the first voltage relationship between the voltage across the rectifier bridge and the target output voltage and the phase shift angle within the bridge, the target phase shift angle within the bridge is determined, and the target phase shift angle within the bridge is sent to the pulse width modulation (PWM) controller 402;

[0075] Adder / subtractor 403 is used to acquire the fundamental component U of the equivalent total input voltage at the receiving end. c2m and the fundamental component U of the voltage across the current rectifier bridge abm The difference between the fundamental component of the equivalent total input voltage at the receiving end and the fundamental component of the voltage at both ends of the rectifier bridge is determined, the current fundamental component difference is obtained, and the current fundamental component difference is sent to the proportional-integral processor 404.

[0076] The proportional-integral processor 404 is used to process the difference of the fundamental component of the current voltage based on proportional-integral calculation to obtain the current inter-bridge phase shift angle, and send the current inter-bridge phase shift angle to the PWM controller 402;

[0077] The PWM controller 402 is used to determine the pulse control signal of the switching transistor in the rectifier circuit based on the target bridge phase shift angle and the current inter-bridge phase shift angle, and when it is determined that the output voltage of the output load is not the target output voltage, it repeatedly instructs the adder and subtractor and the proportional-integral processor to determine the updated inter-bridge phase shift angle, and determines the updated pulse control signal of the switching transistor in the rectifier circuit based on the target bridge phase shift angle and the updated inter-bridge phase shift angle, until the output voltage of the output load is the target output voltage.

[0078] It should be noted that, in the embodiments disclosed herein, the current target output voltage is the voltage value that the output terminal needs to output, which may be the voltage value indicated by the user command obtained by the control system of the wireless power transmission system; when the output voltage of the output load is the target output voltage, the reactive power of the wireless power transmission system is also the lowest.

[0079] The process by which the adder / subtractor and the proportional-integral processor determine the updated inter-bridge phase shift angle may include: the adder / subtractor acquiring the fundamental component U of the equivalent total input voltage at the receiving end. c2mand the fundamental component U of the voltage across the updated rectifier bridge abm The difference between the fundamental component of the equivalent total input voltage at the receiving end and the fundamental component of the voltage across the updated rectifier bridge is determined, and the updated fundamental component difference is obtained. The updated fundamental component difference is then sent to the proportional-integral processor. The proportional-integral processor then processes the updated fundamental component difference based on proportional-integral operations to obtain the updated inter-bridge phase shift angle.

[0080] Understandably, after the proportional-integral processor obtains the updated inter-bridge phase shift angle, it will send the updated inter-bridge phase shift angle to the PWM controller.

[0081] Optionally, during the process of the PWM controller determining the pulse control signal of the switching transistor in the rectifier circuit based on the target bridge phase shift angle and the current bridge phase shift angle, the pulse control signal of the switching transistor in the rectifier circuit is as follows: Figure 5 As shown, with the fifth switch T1 as the reference, the phase difference between the first switch T5 and the fifth switch T1 is α, the phase difference between the fourth switch T8 and the first switch T5 is β, the phase difference between the second switch T6 and the fourth switch T8 is the difference between the unit pulse and β, and the phase difference between the second switch T6 and the third switch T7 is β.

[0082] In summary, the control system of the wireless power transmission system provided in this embodiment can achieve the adjustment of the output voltage of the wireless power transmission system and the control of reactive power based on a dual phase-shift control strategy by using parameters such as the voltage across the rectifier bridge, the target output voltage, the fundamental component of the equivalent input voltage, and the fundamental component of the voltage across the rectifier bridge. This increases the output voltage control range of the wireless power transmission system and facilitates the reduction of reactive power in the wireless power transmission system.

[0083] Example 3

[0084] This disclosure provides a control method for a wireless power transmission system, which is applied to the control system of the wireless power transmission system provided in the above embodiments, such as... Figure 6 As shown, it includes:

[0085] Step S601: Obtain the current target output voltage.

[0086] Step S602: Based on the current target output voltage, the current voltage across the rectifier bridge, and the first voltage relationship between the voltage across the rectifier bridge and the target output voltage and the phase shift angle within the bridge, determine the target phase shift angle within the bridge.

[0087] Step S603: Determine the current inter-bridge phase shift angle based on the fundamental component of the equivalent total input voltage at the receiving end and the fundamental components of the voltages at both ends of the current rectifier bridge.

[0088] Step S604: Based on the target bridge phase shift angle and the current bridge phase shift angle, adjust the output voltage of the output load. If the output voltage of the load is not the target output voltage, repeat the process of determining the updated bridge phase shift angle and adjusting the output voltage of the output load until the output voltage of the output load is the target output voltage.

[0089] In summary, the control method for the wireless power transmission system provided in this disclosure enables power transmission at the receiver based on an LLC network by connecting a compensation inductor in series at the receiver based on an LCC / S resonant network. The LLC network can be equivalent to a receiving coil that satisfies the resonant state connected in series with a compensation inductor, so as to facilitate the use of a dual phase-shift control strategy at the receiver to adjust the rise and fall of the output voltage of the wireless power transmission system, thereby increasing the output voltage control range of the wireless power transmission system.

[0090] It should be noted that, in the embodiments of this disclosure, the process by which the control system of the wireless power transmission system determines the current inter-bridge phase shift angle based on the fundamental component of the equivalent total input voltage at the receiving end and the fundamental component of the voltage across the current rectifier bridge can refer to the implementation scheme for determining the current inter-bridge phase shift angle in the above embodiments, and will not be elaborated upon in this disclosure. The process of determining the updated inter-bridge phase shift angle can also refer to the implementation scheme for determining the updated inter-bridge phase shift angle in the above embodiments, and will not be elaborated upon in this disclosure.

[0091] Example 4

[0092] Based on the above embodiments, when the output voltage of the load is the target output voltage, the control system of the wireless power transmission system can further determine the equivalent load of the receiver based on the load value of the receiver and the target bridge phase shift angle, as well as the correlation between the equivalent load of the receiver and the load value and the bridge phase shift angle. Then, based on the equivalent total input voltage of the receiver, the current voltage across the rectifier bridge, and a second voltage relationship between the system reactive power and the equivalent total input voltage of the receiver, the voltage across the rectifier bridge, and the bridge phase shift angle, the minimum reactive power of the system when the output voltage of the output load is the target output voltage can be determined. A dual phase shift control strategy at the receiver can be adopted to ensure that the reactive power of the wireless power transmission system is minimized while adjusting the output voltage of the wireless power transmission system, thereby reducing system power consumption.

[0093] In the embodiments provided in this disclosure, it should be understood that the disclosed wireless power transmission system, control system, and control method can also be implemented in other ways. The embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of the system, control system, and control method according to various embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0094] It should be noted that, in this disclosure, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element limited by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0095] While the embodiments disclosed herein are as described above, the foregoing content is merely for the purpose of facilitating understanding of this disclosure and is not intended to limit this disclosure. Any person skilled in the art to which this disclosure pertains may make any modifications and changes in form and detail of the implementation without departing from the spirit and scope of this disclosure; however, the scope of patent protection of this disclosure shall still be determined by the scope defined in the appended claims.

Claims

1. A control system for a wireless power transmission system, characterized in that, The wireless power transmission system includes a transmitter and a receiver. The receiver includes an LLC network, a rectifier circuit, and an output load group connected in sequence. The control system includes: The bridge phase shift angle calculator is used to obtain the current target output voltage and acquire the voltage across the current rectifier bridge. Based on the first voltage relationship between the voltage across the rectifier bridge and the target output voltage and the bridge phase shift angle, the target bridge phase shift angle is determined and sent to the pulse width modulation (PWM) controller. The first voltage relationship is: , among which, U ab U is the voltage across the rectifier bridge. 2ref β is the target output voltage, and β is the phase shift angle within the bridge. The adder / subtractor is used to acquire the fundamental component of the equivalent total input voltage at the receiving end and the fundamental component of the voltage across the current rectifier bridge, determine the difference between the fundamental component of the equivalent total input voltage at the receiving end and the fundamental component of the voltage across the current rectifier bridge, obtain the current fundamental component difference, and send the current fundamental component difference to the proportional-integral processor. A proportional-integral processor is used to process the difference of the fundamental component of the current voltage based on proportional-integral calculations to obtain the current inter-bridge phase shift angle, and send the current inter-bridge phase shift angle to the PWM controller; The PWM controller is configured to determine the pulse control signal of the switching transistor in the rectifier circuit based on the target bridge phase shift angle and the current bridge phase shift angle, and when it is determined that the output voltage of the output load is not the target output voltage, repeatedly instruct the adder and subtractor and the proportional-integral processor to determine the updated bridge phase shift angle, and determine the updated pulse control signal of the switching transistor in the rectifier circuit based on the target bridge phase shift angle and the updated bridge phase shift angle, until the output voltage of the output load is the target output voltage.

2. A control method for a wireless power transmission system, characterized in that, The method is applied to the control system of the wireless power transmission system as described in claim 1, comprising: Obtain the current target output voltage; Based on the current target output voltage, the current voltage across the rectifier bridge, and the first voltage relationship between the voltage across the rectifier bridge and the target output voltage and the phase shift angle within the bridge, the target phase shift angle within the bridge is determined. Based on the fundamental component of the equivalent total input voltage at the receiving end, and the fundamental components of the voltages at both ends of the current rectifier bridge, the current inter-bridge phase shift angle is determined; Based on the target bridge phase shift angle and the current bridge phase shift angle, the load output voltage is adjusted. If the load output voltage is not the target output voltage, the process of determining the updated bridge phase shift angle and adjusting the output load output voltage is repeated until the output load output voltage is the target output voltage.

3. The control method for the wireless power transmission system according to claim 2, characterized in that, The method further includes: The equivalent load of the receiver is determined based on the load value of the receiver and the phase shift angle within the target bridge, as well as the correlation between the equivalent load of the receiver and the load value and the phase shift angle within the bridge. Based on the equivalent total input voltage at the receiving end, the current voltage across the rectifier bridge, and the second voltage relationship between the system reactive power and the equivalent total input voltage at the receiving end, the voltage across the rectifier bridge, and the inter-bridge phase shift angle, the minimum reactive power of the system is determined when the output voltage of the output load is the target output voltage. The second voltage relationship is: Among them, R e U is the equivalent load at the receiving end, P is the system reactive power, and U is the system reactive power. c2 U is the equivalent total input voltage at the receiving end. ab α is the voltage across the rectifier bridge, and α is the phase shift angle between the bridges.

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