Half-bridge CLC / S-CLC self-switching constant-current constant-voltage composite wireless power transmission control system and method

Abstract

The invention belongs to the technical field of wireless charging, and particularly relates to a half-bridge CLC / S-CLC self-switching constant-current constant-voltage composite wireless power transmission control system and method. The design is reasonable, a direct-current voltage source is converted into high-frequency alternating current through the high-frequency inversion module, the primary side compensation network and a transmitting coil of the loose coupling transformer are connected to the output end of the high-frequency inversion module in series to form a primary side transmitting circuit, and a receiving coil of the loose coupling transformer and the secondary side compensation network are connected to the input end of the rectification filter circuit in series. The output end of the rectification filter circuit is connected with the load resistor in series, and the detection control circuit is used for detecting the output current and the output voltage of the load resistor and controlling the switching tube. According to the invention, only one control switch is needed to realize constant-current and constant-voltage switching, and the whole system does not need additional compensation devices, so that the cost is greatly reduced; complex closed-loop adjustment control is not needed, and the problem that the system stability is reduced due to depth adjustment is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless charging, and in particular relates to a half-bridge CLC / S-CLC self-switching constant current and constant voltage composite wireless power transmission control system and method. Background Art

[0002] Wireless power transmission technology refers to an energy transmission technology that effectively transfers electrical energy from the power source to the load end through electromagnetic fields, electromagnetic waves or other non-contact media in space without relying on traditional wires or physical contact. Among them, when using magnetic field induction wireless power technology to charge the battery, it can get rid of the physical constraints brought by traditional plug-in cables, making the equipment layout more flexible; it avoids the electric sparks caused by long-term repeated plug-in and unplugging, which may cause electric shock hazards and wear problems. In addition, the development of wireless power transmission technology will not only change people's lifestyles, but also promote the sustainable development of society.

[0003] In order to ensure the safety of the battery and extend its service life, a constant current and constant voltage charging method is usually used when wirelessly charging the battery. This charging method includes two stages: a constant current charging stage and a constant voltage charging stage. In the constant current charging stage, the battery will be charged at a constant rated battery current. During this stage, the battery voltage increases rapidly until it reaches the rated voltage. After the constant current charging stage, it will enter the constant voltage charging stage. The battery will be charged at the rated battery voltage. During this stage, the battery current drops rapidly until it reaches the charging cut-off current. At this point, the entire charging process of the battery is completed.

[0004] However, there are currently several methods to achieve constant current and constant voltage wireless charging of batteries: 1) Add a DC-DC converter in front of the high-frequency inverter module or after the rectifier filter circuit for adjustment. This method can achieve constant current and constant voltage charging by adjusting the duty cycle through closed-loop control, but due to the addition of a DC-DC module, the transmission efficiency of the system is greatly reduced. 2) Use variable frequency control technology to adjust the operating frequency over a wide frequency range to achieve constant current and constant voltage charging, but frequency bifurcation will occur, affecting system stability. 3) Achieving constant current and constant voltage output of the system through hybrid topology switching will introduce additional control switches and additional compensation components, which will undoubtedly increase the size and cost of the system. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned problems existing in the conventional technology and to provide a half-bridge CLC / S-CLC self-switching constant current and constant voltage composite wireless power transmission control system and method.

[0006] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0007] The present invention provides a half-bridge CLC / S-CLC self-switching constant current and constant voltage composite wireless power transmission control system, which mainly includes a DC voltage source, a high-frequency inverter module, a primary compensation network, a switching switch, a secondary compensation network, a loosely coupled transformer, a rectifier filter circuit, a load resistor and a detection control circuit;

[0008] The high-frequency inverter module, the primary compensation network, the loosely coupled transformer, the secondary compensation network and the rectifier filter circuit are connected in sequence, the high-frequency inverter module is connected to a DC voltage source, the rectifier filter circuit is connected to a load resistor, the switching switch is arranged in the high-frequency inverter module, and the switching switch is switched between constant current and constant voltage charging modes under the control of a driving signal generated in the detection control circuit.

[0009] Furthermore, the loosely coupled transformer includes a primary winding and a secondary winding, the primary winding is connected to a primary compensation network, and the secondary winding is connected to a secondary compensation network.

[0010] Furthermore, the high frequency inverter module includes switching transistors S1, S2, and S3.

[0011] Furthermore, the rectification and filtering circuit includes a diode V D1 、V D2 、V D3 、V D4 and filter capacitor C0, diode V D1 、V D4 The diodes V D2 、V D3 The series connection forms another bridge arm, and the series diode V D1 、V D4 The diode V D2 、V D3 And the filter capacitor C0 are connected in parallel.

[0012] Furthermore, the primary compensation network includes a primary compensation capacitor C p , primary compensation inductor L pp And the primary compensation capacitor C ps , the primary compensation capacitor C ps One end is connected to the midpoint of the bridge arm in constant current mode through the switching switch K, and the other end is connected to the primary compensation inductor L pp Parallel and primary compensation capacitor C p The primary compensation capacitor C p The other end is connected to the primary winding; the primary compensation inductor L pp The other end of the primary winding is connected to the midpoint of the bridge arm in the constant voltage mode; the other end of the primary winding is connected to the bottom end of the bridge arm in the constant voltage mode.

[0013] Furthermore, the secondary compensation network includes a secondary compensation capacitor C ss , secondary side compensation inductor L sp and the secondary compensation capacitor C s , the secondary compensation capacitor C s One end is connected to the secondary winding, and the other end is connected to the secondary compensation inductor L sp Parallel and secondary compensation capacitor C ss In series; the compensation capacitor C ss The other end is connected to the midpoint of a bridge arm of the full-bridge rectifier filter circuit; the secondary side compensation inductor L sp The other end and the other end of the secondary winding are connected to the midpoint of the other bridge arm of the rectifier and filter circuit.

[0014] The present invention also provides a half-bridge CLC / S-CLC self-switching constant current constant voltage composite wireless power transmission control switching method, which uses the above-mentioned wireless power transmission control system to control the switching of the charging mode, including the following steps:

[0015] 1) The detection control circuit compares the collected output current and voltage with the optimal load switching point to generate a constant current control instruction or a constant voltage control instruction;

[0016] 2) The switching transistors in the high-frequency inverter module select different switching transistors for driving according to the constant current control instruction or the constant voltage control instruction, and the switching switch K is turned on or off according to the constant current control instruction or the constant voltage control instruction.

[0017] Furthermore, in step 1), when the switching transistor in the high-frequency inverter module receives a constant current control instruction, the switching transistors S1 and S2 form a half-bridge inverter circuit for driving, the switching transistor S3 is continuously turned on, the switching switch K is turned on, and the primary side compensation network and the secondary side compensation network form a CLC-CLC compensation network with a constant current whose output is independent of the load, thereby realizing a constant current charging mode.

[0018] Furthermore, in step 1), when the switching transistor in the high-frequency inverter module receives a constant voltage instruction, the switching transistors S2 and S3 form a half-bridge inverter circuit for driving, the switching transistor S1 is continuously turned on, the switching switch K is turned off, and the primary side compensation network and the secondary side compensation network form an S-CLC compensation network with an output having a constant voltage that is independent of the load, thereby realizing a constant voltage charging mode.

[0019] Furthermore, in step 1), the real-time load value collected by the detection control circuit is compared with the optimal load value. When the real-time load value is less than the optimal load value, the detection control circuit generates a constant current control instruction; when the real-time load value is greater than the optimal load value, the detection control circuit generates a constant voltage control instruction.

[0020] The beneficial effects of the present invention are:

[0021] 1. The present invention only needs to construct a transmitter compensation network in the primary circuit of the loosely coupled transformer, and the circuit structure is simple. Compared with the full-bridge driving mode, the half-bridge driving mode only requires one control switch, which reduces the use of control switches and reduces the complexity of the system. The primary side topology switching does not require additional compensation devices, which greatly reduces the cost and improves stability. It does not require a complex control circuit to achieve switching between constant current and constant voltage charging modes.

[0022] 2. The present invention can realize constant current and constant voltage switching regardless of load at the same frequency, can meet the charging requirements of constant current first and then constant voltage during battery charging, avoid frequency bifurcation, and the system can work stably.

[0023] 3. The present invention can be used for wireless charging of electric vehicles. The mutual inductance M between the coils is fixed. The system can detect the real-time load value and then compare it with the optimal load value so as to switch at the optimal load to ensure the normal operation of the system.

[0024] Of course, any product implementing the present invention does not necessarily need to achieve all of the above advantages at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0026] Figure 1 The main circuit and control block diagram of the system in the embodiment of the present invention;

[0027] Figure 2 Schematic diagram of the CLC-CLC compensation network formed by switching the switch closed and S1 and S2 driven;

[0028] Figure 3 Schematic diagram of the S-CLC compensation network formed by switching off the switch and driving S2 and S3;

[0029] Figure 4 : is a fundamental wave equivalent circuit diagram of a CLC-CLC constant current charging mode in an embodiment of the present invention;

[0030] Figure 5 is a fundamental wave equivalent circuit diagram of the S-CLC constant voltage charging mode in an embodiment of the present invention;

[0031] Figure 6 A logic flow chart of a system control method in an embodiment of the present invention;

[0032] Figure 7 Schematic diagram of the switch tube driving method in the CLC-CLC constant current charging mode in an embodiment of the present invention;

[0033] Figure 8 Schematic diagram of the switch tube driving method in the S-CLC constant voltage charging mode in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] like Figure 1 The wireless power transmission system shown in the figure includes a primary transmitting end and a secondary receiving end, wherein the primary transmitting end includes a DC voltage source, a high frequency inverter module, a primary compensation network, a primary winding L connected in sequence p The primary compensation network includes a compensation capacitor C p , compensation inductance L pp , compensation capacitor C ps , the primary CLC compensation network formed by the switching switch K (this primary CLC compensation network is driven by the half-bridge inverter circuit formed by S1 and S2), and the compensation inductor L when the switching switch K is disconnected pp and compensation capacitor C p The series compensation network formed by series connection (this series compensation network is driven by the half-bridge inverter circuit formed by S2 and S3) is converted into an S-CLC compensation network by the bilateral CLC compensation network, and no additional compensation devices are required. The secondary receiving end includes the compensation capacitor C ss , compensation inductance L sp , compensation capacitor C s The secondary side CLC compensation network is formed. p and the secondary winding L s A loosely coupled transformer is formed, and the mutual inductance between the two is M.

[0036] like Figure 2 As shown, when the switching controller receives the constant current charging instruction, it controls the switching switch K to close, at which time the half-bridge inverter circuit formed by S1 and S2 starts to work, and S3 is continuously turned on. The wireless power transmission system can form a constant current bilateral CLC compensation network with an output current independent of the load by the primary side CLC compensation network and the secondary side CLC compensation network, thereby realizing a CLC-CLC constant current charging mode.

[0037] like Figure 3 As shown, when the switching controller receives a constant voltage charging instruction, it controls the switching switch K to be disconnected, at which time the half-bridge inverter circuit formed by S2 and S3 starts to work, and S1 is continuously turned on. The wireless power transmission system can form a constant voltage S-CLC compensation network with an output voltage independent of the load by the primary side series compensation network and the secondary side CLC compensation network, thereby realizing the S-CLC constant voltage charging mode.

[0038] In this embodiment, the high frequency inverter module is composed of switch transistors S1 , S2 , and S3 , and the switch transistors S1 , S2 , and S3 are respectively connected in series.

[0039] In this embodiment, the full-bridge rectifier filter circuit includes a diode V D1 、V D2 、V D3 、V D4 and filter capacitor C0, where the diode V D1 、V D4 Connected in series, the diodes V D2 、V D3 connected in series, the diodes V D1 、V D4 and V D2 、V D3 connected in parallel, and the capacitor C0 and the series diode V D2 、V D3 And the series V D1 、V D4 Connected in parallel.

[0040] Set each resonant loop to meet the following conditions:

[0041]

[0042] When the system is working in the constant current charging stage, the operating status of each switch tube in the high-frequency inverter module is as follows:

[0043] S1: half-cycle conduction, and the conduction time is complementary to that of S2; S2: half-cycle conduction, and the conduction time is complementary to that of S1; S3: continuous conduction state; switch K: continuous conduction state. Its fundamental wave equivalent circuit is as follows: Figure 4 As shown, the AC voltage source V mid1 With the DC voltage source V shown in the figure in The relationship is as follows:

[0044]

[0045] AC output current I o The DC output current I L The relationship is as follows:

[0046]

[0047] Using the mesh current method Figure 4 Analyze the circuit shown and write the following equation:

[0048]

[0049] Solving the above equation gives the output current:

[0050]

[0051] Substituting the above formula into the formula, we can get:

[0052]

[0053] It can be seen from the formula that the output current I L With load R L Not relevant.

[0054] When the system is operating in the constant voltage charging stage, the operating status of each switch tube in the high-frequency inverter module is as follows:

[0055] S1: continuous conduction state; S2: half-cycle conduction, and the conduction time is complementary to S3; S3: half-cycle conduction, and the conduction time is complementary to S2; switch K: continuous off state. Its fundamental wave equivalent circuit is as follows Figure 5 As shown, the AC voltage source V mid2 With the DC voltage source V shown in the figure in The relationship is as follows:

[0056]

[0057] AC output voltage V o The battery voltage V L The relationship is as follows:

[0058]

[0059] Using the mesh current method Figure 5 Analyze the circuit shown and write the following equation:

[0060]

[0061] Solving the above equation gives the output voltage

[0062]

[0063] Substituting the above formula into the formula, we can get:

[0064]

[0065] It can be seen from the formula that the output voltage V L With load R L Not relevant.

[0066] The system parameters are determined as follows:

[0067] The compensation inductor L in the primary compensation network pp The inductance value is:

[0068]

[0069] The compensation capacitor C in the primary compensation network ps The capacitance value is:

[0070]

[0071] The compensation capacitor C in the primary compensation network p The capacitance value is:

[0072]

[0073] The compensation inductor L in the secondary compensation network sp The inductance value is:

[0074]

[0075] The compensation capacitor C in the secondary compensation network ss The capacitance value is:

[0076]

[0077] The compensation capacitor C in the secondary compensation network s The capacitance value is:

[0078]

[0079] In the above formula, V in is the output voltage of the DC voltage source; ω is the system operating angular frequency; I L 、V L They are the rated current and rated voltage for charging the battery; L p , L s are the inductance of the primary transmitting coil and the secondary receiving coil respectively; M is the mutual inductance between the primary transmitting coil and the secondary receiving coil.

[0080] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A half-bridge CLC / S-CLC self-switching constant current and constant voltage composite wireless power transmission control system, characterized in that: The system mainly includes a DC voltage source, a high-frequency inverter module, a primary compensation network, a switching switch, a secondary compensation network, a loosely coupled transformer, a rectifier filter circuit, a load resistor and a detection control circuit; The high-frequency inverter module, the primary compensation network, the loosely coupled transformer, the secondary compensation network and the rectifier filter circuit are connected in sequence, the high-frequency inverter module is connected to a DC voltage source, the rectifier filter circuit is connected to a load resistor, the switching switch is arranged in the high-frequency inverter module, and the switching switch is switched between constant current and constant voltage charging modes under the control of a driving signal generated in the detection control circuit.

2. The half-bridge CLC / S-CLC self-switching constant current and constant voltage composite wireless power transmission control system according to claim 1, characterized in that: The loosely coupled transformer comprises a primary winding and a secondary winding, wherein the primary winding is connected to a primary compensation network, and the secondary winding is connected to a secondary compensation network.

3. The half-bridge CLC / S-CLC self-switching constant current and constant voltage composite wireless power transmission control system according to claim 2, characterized in that: The high frequency inverter module includes switching transistors S1, S2, and S3.

4. The half-bridge CLC / S-CLC self-switching constant current and constant voltage composite wireless power transmission control system according to claim 3 is characterized in that: The rectifying and filtering circuit includes a diode V D1 、V D2 、V D3 、V D4 and filter capacitor C0, diode V D1 、V D4 The diodes V D2 、V D3 The series connection forms another bridge arm, and the series diode V D1 、V D4 The diode V D2 、V D3 And the filter capacitor C0 are connected in parallel.

5. The half-bridge CLC / S-CLC self-switching constant current and constant voltage composite wireless power transmission control system according to claim 4, characterized in that: The primary compensation network includes a primary compensation capacitor C p , primary compensation inductor L pp And the primary compensation capacitor C ps , the primary compensation capacitor C ps One end is connected to the midpoint of the bridge arm in constant current mode through the switching switch K, and the other end is connected to the primary compensation inductor L pp Parallel and primary compensation capacitor C p The primary compensation capacitor C p The other end is connected to the primary winding; the primary compensation inductor L pp The other end of the primary winding is connected to the midpoint of the bridge arm in the constant voltage mode; the other end of the primary winding is connected to the bottom end of the bridge arm in the constant voltage mode.

6. The half-bridge CLC / S-CLC self-switching constant current and constant voltage composite wireless power transmission control system according to claim 5, characterized in that: The secondary side compensation network includes a secondary side compensation capacitor C ss , secondary side compensation inductor L sp And the secondary compensation capacitor C s , the secondary compensation capacitor C s One end is connected to the secondary winding, and the other end is connected to the secondary compensation inductor L sp Parallel and secondary compensation capacitor C ss Series; the compensation capacitor C ss The other end is connected to the midpoint of a bridge arm of the full-bridge rectifier filter circuit; the secondary side compensation inductor L sp The other end and the other end of the secondary winding are connected to the midpoint of the other bridge arm of the rectifier and filter circuit.

7. A half-bridge CLC / S-CLC self-switching constant current and constant voltage composite wireless power transmission control switching method, characterized in that: The wireless power transmission control system according to claim 6 is used to control the switching of the charging mode, comprising the following steps: 1) The detection control circuit compares the collected output current and voltage with the optimal load switching point to generate a constant current control instruction or a constant voltage control instruction; 2) The switching transistors in the high-frequency inverter module select different switching transistors for driving according to the constant current control instruction or the constant voltage control instruction, and the switching switch K is turned on or off according to the constant current control instruction or the constant voltage control instruction.

8. The half-bridge CLC / S-CLC self-switching constant current and constant voltage composite wireless power transmission control switching method according to claim 7, characterized in that: In step 1), when the switching transistor in the high-frequency inverter module receives a constant current control instruction, the switching transistors S1 and S2 form a half-bridge inverter circuit for driving, the switching transistor S3 is continuously turned on, the switching switch K is turned on, and the primary side compensation network and the secondary side compensation network form a CLC-CLC compensation network with a constant current whose output is independent of the load, thereby realizing a constant current charging mode.

9. The half-bridge CLC / S-CLC self-switching constant current and constant voltage composite wireless power transmission control switching method according to claim 8, characterized in that: In step 1), when the switching transistor in the high-frequency inverter module receives a constant voltage instruction, the switching transistors S2 and S3 form a half-bridge inverter circuit for driving, the switching transistor S1 is continuously turned on, the switching switch K is turned off, and the primary side compensation network and the secondary side compensation network form an S-CLC compensation network with a constant voltage output that is independent of the load, thereby realizing a constant voltage charging mode.

10. The half-bridge CLC / S-CLC self-switching constant current and constant voltage composite wireless power transmission control switching method according to claim 9, characterized in that: In step 1), the real-time load value collected by the detection control circuit is compared with the optimal load value. When the real-time load value is less than the optimal load value, the detection control circuit generates a constant current control instruction; when the real-time load value is greater than the optimal load value, the detection control circuit generates a constant voltage control instruction.

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