CN114678968A - A high and low voltage compatible wireless power transmission system and method for manufacturing the same resonant inductance integrated transformer - Google Patents

Abstract

The invention relates to a high-low voltage compatible wireless power transmission system and a manufacturing method of a resonance inductor integrated transformer thereof, wherein the system comprises a transmitting coil end and a receiving coil end; the receiving coil end further comprises a resonance inductance integrated transformer, a primary winding of the resonance inductance integrated transformer is connected with the receiving end LCC compensation network, a secondary winding of the resonance inductance integrated transformer is connected with the receiving end rectifier bridge, leakage inductance of the primary winding of the resonance inductance integrated transformer replaces the receiving end LCC compensation network to compensate inductance, so that the receiving coil end reaches a resonance state under a rated frequency, and the primary winding and the secondary winding of the resonance inductance integrated transformer are compatible with a high-voltage and low-voltage charging rechargeable battery by changing the transformation ratio of the primary winding and the secondary winding of the resonance inductance integrated transformer. The resonant inductor integrated transformer has the beneficial effects that impedance matching is realized by replacing a resonant compensation inductor with the resonant inductor integrated transformer, and the charging requirements of different voltage levels are met.

Description

A high and low voltage compatible wireless power transmission system and its resonant inductance integrated transformer manufacturing method

【Technical field】

The invention relates to the technical field of power electronic converters, in particular to a high and low voltage compatible wireless power transmission system and a method for manufacturing a resonant inductance integrated transformer.

【Background technique】

Wireless power transfer (WPT) technology utilizes magnetic field coupling to realize energy transmission without direct electrical connection, and has the advantages of safety, convenience, and high reliability. In recent years, WPT technology has been applied to mobile phone charging, implantable medical treatment, robotics, electric vehicle charging and other fields, especially in the field of electric vehicle wireless charging, which has a good development prospect. Huawei, WiTricity, VIE and other companies are at the forefront of technology in the field of wireless charging for electric vehicles, and are gradually putting them into practical applications. Therefore, the research on WPT not only has academic significance, but also has strong social application value.

At present, the widely used electric vehicle wireless charging system generally adopts bilateral LCC topology as the compensation network. The transmitter coil end (Ground assembly, GA) is buried in the ground, and usually the parameters are not easily changed after selection; the receiver coil end (Vehicle assembly, VA) is placed on the side In the car, it is designed according to the conditions of the space in the car, the transmission power level, and the charging voltage of the load battery. The charging voltage of the load battery is usually 400V, and it is required that charging can be achieved in a wide range around a given load voltage. With the development of battery technology, the voltage of rechargeable batteries has been raised from 400V to 800V, and 800V batteries are gradually being put into use. High-voltage batteries can increase the charging power and improve the power density of the system under the same charging current condition, which is a development trend, which also brings challenges to the wireless charging of electric vehicles. The design of the GA terminal and the VA terminal depends on the charging voltage of the rechargeable battery. The increase of the charging voltage leads to the change of the coil parameters of the VA terminal and the compensation network parameters. One solution is to remake the VA terminal suitable for 800V battery voltage, which is expensive for actual production and is not conducive to product normalization design. The second solution is to add a DC-DC converter at the rear stage of the rectifier side, which can solve the problem of load voltage changes, but after adding a first-stage converter, the transmission efficiency of the system will be reduced, which will be lower than the minimum required under the SAE J2954 standard. Energy transmission efficiency, and the volume of the vehicle-end device is too large to meet the stringent application requirements of car companies.

Existing wireless power transmission power adjustment methods, such as phase-shift control and frequency modulation control, are difficult to deal with the challenges brought by the wide range of output voltages of high and low voltage batteries; designing a separate system for each application scenario increases the project cost and is not conducive to different equipment. compatibility between them; and adding an additional DC-DC power conditioning circuit will bring about a significant drop in efficiency. Therefore, there is an urgent need for a high-efficiency, high-power wireless charging technical solution for electric vehicles that is compatible with high and low voltage batteries.

The main components of the transformer are the iron core and the two windings set on the iron core, and the two windings have magnetic coupling. An alternating voltage is added to the primary winding to generate alternating magnetic fluxes that link the primary and secondary windings, and electromotive force is induced in the two windings respectively. When the primary winding is connected to the AC power supply, an AC current flows in the winding, and a magnetic flux with the same frequency as the applied voltage is generated in the iron core. This alternating magnetic flux links the primary winding and the secondary winding at the same time. . Transformer leakage inductance refers to the fact that the magnetic lines of force generated by the coil (primary side) cannot all pass through the secondary coil (secondary side), so the inductance that produces magnetic leakage is called leakage inductance.

There are many reports on the transformer with integrated resonant inductor (Resonant Inductor Integrated Transformer, RIIT). For example, the application (patent) number: CN202022860514.8 utility model "Transformer with integrated resonant inductor"; application (patent) number: CN202121541913.6 practical The new "Transformer with Integrated Resonant Inductance"; Application (Patent) No.: CN201821274694.8 Utility Model "An LLC Half-Bridge Transformer with Integrated Resonant Inductance", etc.

Aiming at the technical problem of compatible charging of high and low voltage loads existing in the wireless charging technology of electric vehicles, the present invention improves the wireless charging technology of electric vehicles by using the transformer technology integrating resonant inductance.

[Content of the invention]

The purpose of the present invention is to provide a high and low voltage compatible wireless power transmission system that uses a resonant inductance integrated transformer to replace the resonant compensation inductance to achieve impedance matching and is compatible with charging requirements of different voltage levels.

In order to achieve the above purpose, the technical solution adopted by the present invention is a high and low voltage compatible wireless power transmission system, which includes a transmitting coil end and a receiving coil end; the transmitting coil end includes a transmitting end inverter and a transmitting end LCC compensation connected in sequence. network and transmitter coil; the receiver coil end includes a receiver coil and a receiver LCC compensation network connected to each other, and a receiver rectifier bridge and a rechargeable battery connected to each other; the receiver coil also includes a resonant inductance integrated transformer, so The primary winding of the resonant inductance integrated transformer is connected to the LCC compensation network of the receiving end, the secondary winding of the resonant inductance integrated transformer is connected to the rectifier bridge of the receiving end, and the leakage inductance L _r of the primary winding of the resonant inductance integrated transformer replaces the LCC compensation of the receiving end The network compensation inductance L _{f_va} makes the receiving coil end reach a resonance state at the rated frequency, and is compatible with high and low voltage rechargeable batteries by changing the transformation ratio of the primary winding and the secondary winding of the resonant inductance integrated transformer.

Preferably, the high-voltage and low-voltage compatible wireless power transmission system is compatible with charging of high-voltage rechargeable batteries and low-voltage rechargeable batteries, and the charging voltage of the high-voltage rechargeable battery is twice that of the low-voltage rechargeable battery, including two fixed transformation ratios The resonant inductance integrated transformer and two receiving end rectifier bridges are connected to the receiving end LCC compensation network after the primary windings of the two fixed ratio resonant inductance integrated transformers are connected in series; when charging the low-voltage rechargeable battery, the two fixed The secondary windings of the resonant inductance integrated transformer with variable ratio are respectively connected to two receiving end rectifier bridges and output in parallel to charge the low-voltage rechargeable battery; when charging the high-voltage rechargeable battery, the two fixed-ratio resonant inductance integrated transformer secondary windings The windings are respectively connected to two receiving end rectifier bridges and then output in series to charge the high-voltage rechargeable battery.

Preferably, the high-voltage and low-voltage compatible wireless power transmission system further includes a first voltage-balancing auxiliary coil and a second voltage-balancing auxiliary coil for assisting in realizing voltage-balancing output when charging a high-voltage rechargeable battery. A voltage equalizing auxiliary coil and a second voltage equalizing auxiliary coil are respectively wound on the magnetic cores of the two fixed ratio resonant inductance integrated transformers to form a loop, and the two fixed ratio resonant inductance integrated transformer magnetic The difference in the change rate of the flux linkage in the core is compensated for the flux linkage to achieve automatic voltage equalization output.

所述第一均压辅助线圈和第二均压辅助线圈磁通计算公式：Φ_rec1＝Φ₁-Φ_aux、Φ_rec1＝Φ₁+Φ_aux，当两个接收端整流桥串联输出电压出现偏差时，在所述第一均压辅助线圈和第二均压辅助线圈内产生感应电流，在磁通大的谐振电感集成变压器磁芯中产生反向磁通，在磁通小的谐振电感集成变压器磁芯中产生正向磁通，抵消两个接收端整流桥串联输出电压的不平衡，实现自动均压输出。Preferably, the self-inductance of the first voltage-balancing auxiliary coil is L _aux1 , the self-inductance of the second voltage-balancing auxiliary coil is L _aux2 , the two fixed-ratio resonant inductances integrate the primary winding turns of the transformer and two The number of turns of the secondary winding is n ₁ and n ₂ respectively, the number of turns of the first voltage equalization auxiliary coil and the second voltage equalization auxiliary coil is n ₃ , and Ф ₁ , Ф _aux , Ф _rec1 and Ф _rec2 are the receiving ends respectively. The output current i ₁ of the LCC compensation network, the primary winding current i _aux of the two fixed-ratio resonant inductor integrated transformers, and the two receiving-end rectifier bridge currents i _rec1 and i _{rec2 are} excited to generate the magnetic flux. The formula for calculating the current of the coil and the second voltage equalizing auxiliary coil:

The magnetic flux calculation formulas of the first voltage equalization auxiliary coil and the second voltage equalization auxiliary coil are as follows: Φ _rec1 =Φ ₁ -Φ _aux , Φ _rec1 =Φ ₁ +Φ _aux , when the output voltage of the two receiving end rectifier bridges is deviated in series When the magnetic flux is large, an induced current is generated in the first voltage-sharing auxiliary coil and the second voltage-sharing auxiliary coil, a reverse magnetic flux is generated in the magnetic core of the resonant inductance integrated transformer with large magnetic flux, and a resonant inductance integrated transformer with small magnetic flux is generated. A forward magnetic flux is generated in the magnetic core, which offsets the unbalance of the output voltage of the two receiving end rectifier bridges in series, and realizes automatic voltage equalization output.

Preferably, the charging voltage of the high-voltage rechargeable battery is 800V, and the charging voltage of the low-voltage rechargeable battery is 400V.

Another object of the present invention is to provide a method for manufacturing a resonant inductance integrated transformer that replaces the resonant compensation inductance with a resonant inductance integrated transformer to achieve impedance matching and is compatible with high and low voltage compatible wireless power transmission systems with different voltage levels of charging requirements.

In order to achieve the above-mentioned another object, the technical solution adopted by the present invention is a method for manufacturing a resonant inductance integrated transformer of a high-low voltage compatible wireless power transmission system, which is used for the manufacture of the resonant inductance integrated transformer of a high-low voltage compatible wireless power transmission system, Include the following steps:

S1. According to the charging voltage of the rechargeable battery, the transmission power of the system, the leakage inductance L _r of the primary winding of the resonant inductance integrated transformer, and the space limitation, make a preliminary calculation on the coil transformation ratio and output current of the resonant inductance integrated transformer, and select the coil diameter of the resonant inductance integrated transformer. ;

S2. Select the material and shape of the magnetic core of the resonant inductor integrated transformer, and determine the transformation ratio of the resonant inductor integrated transformer;

S3. Estimate the leakage inductance L _r of the primary winding of the resonant inductance integrated transformer, and calculate the power loss P _o of the resonant inductance integrated transformer. If the requirements are not met, step S2 is performed, otherwise, S5 is performed;

S4. Make a prototype of a resonant inductor integrated transformer;

S5, perform parameter test on the prototype of the resonant inductance integrated transformer, if it is unqualified, perform step S2, otherwise obtain the target resonant inductance integrated transformer.

系统输出功率为

其中μ为谐振电感集成变压器磁芯的磁导率，A_e为谐振电感集成变压器磁芯的有效截面积，l_e为谐振电感集成变压器磁路长度，k_riit为谐振电感集成变压器线圈间的耦合系数，M为谐振电感集成变压器线圈间的互感系数，L_ga、L_va、L_{f_ga}、L_{f_va}分别为发射端线圈自感、接收端线圈自感、发射端LCC补偿网络补偿电感、接收端LCC补偿网络补偿电感，ω为谐振角频率，V_bus、V_bat1、V_bat2分别为直流母线电压、高压充电电池的充电电压和低压充电电池的充电电压。Preferably, in the method for manufacturing a resonant inductance integrated transformer of a high and low voltage compatible wireless power transmission system, the resonant inductance integrated transformer primary winding inductance L ₁ =μn ² A _e / _le , the resonant inductance integrated transformer primary winding leakage inductance

The system output power is

where μ is the magnetic permeability of the resonant inductor integrated transformer core, A _e is the effective cross-sectional area of the resonant inductor integrated transformer core, l _e is the magnetic circuit length of the resonant inductor integrated transformer, and k _riit is the coupling between the resonant inductor integrated transformer coils coefficient, M is the mutual inductance coefficient between the resonant inductor integrated transformer coils, L _ga , L _va , L _{f_ga} , L _{f_va} are the self-inductance of the transmitter coil, the receiver coil self-inductance, the transmitter LCC compensation network compensation inductance, the receiver LCC The compensation network compensates the inductance, ω is the resonant angular frequency, V _bus , V _bat1 , and V _bat2 are the DC bus voltage, the charging voltage of the high-voltage rechargeable battery and the charging voltage of the low-voltage rechargeable battery, respectively.

Preferably, the magnetic core of the resonant inductor integrated transformer is an iron core.

A high-low voltage compatible wireless power transmission system and a method for making a resonant inductance integrated transformer of the present invention have the following beneficial effects: the ground end of the system remains unchanged, compatible with all vehicle models, and the resonant inductance integrated transformer at the vehicle end replaces the resonant compensation inductance of the conventional system Realize impedance matching; realize impedance matching through the connection method of the transformer and the leakage inductance and transformation ratio of the designed transformer to adapt to different charging voltages; when the transformation ratio of the resonant inductance integrated transformer is fixed, it can be realized by changing the series-parallel relationship on the DC output side. The charging voltage of the load battery is compatible between 400V and 800V; the battery charging requirements of different voltage levels are compatible with the series-parallel connection of the modules, different power levels are obtained by increasing the number of modules, and the natural inter-module between multiple rectifiers is realized through the small auxiliary winding. For voltage equalization and current equalization, the first voltage equalization auxiliary coil L _aux1 and the second voltage equalization auxiliary coil L _aux2 are respectively wound on two transformer cores to realize voltage equalization of multiple modules in series, with small current and small volume; Applicable to battery charging voltages of different voltage levels, with automatic voltage equalization and current equalization output characteristics between modules, compact structure and high power density; suitable for occasions where the voltage of rechargeable batteries changes, replacing the traditional redesign parameters and adding DC-DC The method of the converter greatly reduces the cost of the system, improves the efficiency of the system, and realizes the voltage and current sharing between the rectifiers.

【Description of drawings】

Figure 1 is a circuit schematic diagram of a high and low voltage compatible wireless power transmission system.

FIG. 2 is an equivalent circuit diagram of the receiving coil end of a high and low voltage compatible wireless power transmission system.

Figure 3 is a flow chart of the fabrication of a dual-resonant inductance integrated transformer at the receiving coil end of a high and low voltage compatible wireless power transmission system.

Figure 4 is a parallel equivalent circuit diagram of the output of a resonant inductance integrated transformer at the receiving coil end of a high and low voltage compatible wireless power transmission system.

Figure 5 is an equivalent circuit diagram of a high-low voltage compatible wireless power transmission system receiving coil end circuit resonant inductor integrated transformer output series equivalent circuit diagram.

FIG. 6 is a schematic diagram of the principle of realizing voltage equalization in series with the output of a resonant inductor integrated transformer in a receiving coil end circuit of a high and low voltage compatible wireless power transmission system.

Figure 7 is an equivalent circuit diagram of a high and low voltage compatible wireless power transmission system receiving coil end circuit resonant inductance integrated transformer output in series to achieve voltage equalization.

【Detailed ways】

The present invention will be further described below in conjunction with the embodiments and with reference to the accompanying drawings.

Example 1

This embodiment implements a high and low voltage compatible wireless power transmission system.

This embodiment is a high and low voltage compatible wireless power transmission system, which can be compatible with charging requirements of different voltage levels through the series-parallel connection of modules, and can automatically achieve voltage equalization and current equalization output between modules. This embodiment is a high and low voltage compatible wireless power transmission system. By designing the leakage inductance and transformation ratio of the transformer, the integration of the resonant inductance and the transformer is simply and efficiently realized. The way of redesigning parameters and adding DC-DC converters greatly reduces the cost of the wireless power transfer system, improves the efficiency of the wireless power transfer system, and realizes voltage and current sharing between the rectifiers.

Figure 1 is a circuit schematic diagram of a high and low voltage compatible wireless power transmission system. As shown in FIG. 1 , the circuit topology of a high and low voltage compatible wireless power transmission system in this embodiment includes an inverter at the GA end, an LCC compensation network at the GA end, a transmitting coil at the GA end, a receiving coil at the VA end, and a resonant inductor at the VA end. LCC compensation network including transformer leakage inductance L _r , VA side rectifier bridge and rechargeable battery.

This embodiment is a high and low voltage compatible wireless power transmission system, which can realize the integration of compensation inductance and the matching of charging voltage at the same time by means of designing leakage inductance and transformation ratio, and has a compact structure and high power density. FIG. 2 is an equivalent circuit diagram of the receiving coil end of a high and low voltage compatible wireless power transmission system. As shown in FIG. 2 , the design of the resonant inductance integrated transformer in this embodiment includes: the design of the leakage inductance L _r of the transformer, the design of the transformer transformation ratio n, the design of the auxiliary voltage equalizing coils L _aux1 and L _aux2 , and the design of the connection mode of the transformer , in which the transformer leakage inductance L _r is used as the resonant inductance in the LCC compensation network of the on-board terminal in the wireless power transmission system, and is connected with the two resonant capacitors C _va and C _f-va in the connection mode shown in Figure 1, so that the receiving end is at rated The resonant state is reached at the frequency, and the equivalent circuit diagram is obtained.

Figure 3 is a flow chart of the fabrication of a dual-resonant inductance integrated transformer at the receiving coil end of a high and low voltage compatible wireless power transmission system. As shown in FIG. 3 , a high-low voltage compatible wireless power transmission system in the present embodiment uses a dual-resonant inductance integrated transformer to achieve 400V/800V output. The production process of the dual-resonant inductance integrated transformer is as follows: The transmission power, the leakage inductance and the space limitation of the coil are preliminarily calculated for the transformation ratio of the coil and the output current, and the resonant inductance integrated transformer is wound according to the calculation results; the transformer coil self-inductance L ₁ , leakage inductance L _r and transmission power P _oCalculation can be carried out according to formulas (1)-(3), so as to select materials, transformer ratio, etc., and finally, according to the calculation results, a transformer prototype that meets the system requirements, that is, the transformer leakage inductance meets the requirements, can be produced; where μ is the iron core The magnetic permeability of , A _e is the effective cross-sectional area of the iron core, l _e is the length of the magnetic circuit, k _riit is the coupling coefficient between the transformer coils, M is the mutual inductance coefficient between the transformer coils, L _ga , L _va , L _{f_ga} , L _{f_va} are the self-inductance of the ground-side transmitting coil, the self-inductance of the vehicle-side receiving coil, the ground-side compensation inductance, and the receiving-end compensation inductance, respectively, ω is the resonance angular frequency, V _bus , V _bat1 , and V _bat2 are the DC bus voltage and the two The voltage of the rechargeable battery.

L ₁ =μn ² A _e /l _e (1)

This embodiment is a high and low voltage compatible wireless power transmission system. The resonant inductance integrated transformer is placed in the front stage of the load rectifier bridge, and the leakage inductance L _r of the primary side coil of the resonant inductance integrated transformer is used as the resonant inductance L of the LCC compensation network at the VA end. _{f_va} , no additional resonant inductance is required, which reduces the size of the device; the transformation ratio n of the resonant inductor integrated transformer realizes the voltage change of the primary side and the secondary side of the resonant inductor integrated transformer, and realizes impedance matching, which can be changed by changing the transformation ratio n. Change the output voltage under the current parameters of the bilateral LCC resonant network.

This embodiment is a high-voltage and low-voltage compatible wireless power transmission system. When the transformation ratio n of the resonant inductor integrated transformer is fixed, two above-mentioned fixed ratio resonant inductor integrated transformers can be placed in the front stage of the rectifier bridge. By changing the two fixed transformation ratio resonance The series-parallel relationship of the output of the inductor integrated transformer realizes the conversion of the charging voltage of the load battery between 400V and 800V.

Figure 4 is a parallel equivalent circuit diagram of the output of a resonant inductance integrated transformer at the receiving coil end of a high and low voltage compatible wireless power transmission system. As shown in FIG. 4 , in this embodiment, a high-low voltage compatible wireless power transmission system, the connection method of the resonant inductance integrated transformer and the transformation ratio n of the resonant inductance integrated transformer jointly realize impedance matching. When the outputs are connected in parallel, the transformer adopts FIG. 4 The connection method shown, and the transformation ratio n of the transformer is changed according to the demand for the output voltage, so that the charging voltage of 400V can be adapted without changing other configurations of the circuit.

Figure 5 is an equivalent circuit diagram of a high-low voltage compatible wireless power transmission system receiving coil end circuit resonant inductor integrated transformer output series equivalent circuit diagram. As shown in FIG. 5 , a high-low voltage compatible wireless power transmission system in this embodiment, the connection method of the resonant inductance integrated transformer and the transformation ratio n of the resonant inductance integrated transformer jointly realize impedance matching. When the outputs are connected in series, the transformer adopts the method shown in FIG. 5 The connection method shown, and the transformation ratio n of the transformer is changed according to the demand for the output voltage, so that the charging voltage of 800V can be adapted without changing other configurations of the circuit.

FIG. 6 is a schematic diagram of the principle of realizing voltage equalization in series with the output of a resonant inductor integrated transformer in a receiving coil end circuit of a high and low voltage compatible wireless power transmission system. Figure 7 is an equivalent circuit diagram of a high and low voltage compatible wireless power transmission system receiving coil end circuit resonant inductance integrated transformer output in series to achieve voltage equalization. As shown in FIG. 6 and FIG. 7 , a high-low voltage compatible wireless power transmission system in this embodiment, when the output series resonant inductance integrated transformer connection mode is adopted, the first voltage equalizing auxiliary coil L _aux1 and the second voltage equalizing The auxiliary coil L _aux2 is used to assist the WPT system to achieve voltage equalization output, and is wound in the manner shown in FIG. 6 . The first voltage equalization auxiliary coil L _aux1 and the second voltage equalization auxiliary coil L _aux2 are respectively wound on the above two transformers. On the magnetic core of the transformer, a loop is formed, and the difference in the flux linkage change rate in the two transformer cores is used to compensate the flux linkage to realize automatic voltage equalization output, which can realize the automatic voltage equalization output of the wireless power transmission system, and the obtained equivalent circuit diagram As shown in Figure 7; the rear stage of the resonant inductor integrated transformer transformer is connected to the rectifier filter circuit shown in Figure 1 or other forms of rectifier filter circuits to obtain the required DC voltage output.

Example 2

This embodiment implements a high and low voltage compatible wireless power transmission system. This embodiment is implemented on the basis of Embodiment 1.

In this embodiment, a high and low voltage compatible wireless power transmission system is designed according to the original 400V battery charging voltage for wireless charging of electric vehicles. The resonant inductance integrated transformer is used to replace the VA terminal resonant inductance, and the transformation ratio of the resonant inductance integrated transformer is set to n=1, it can be used to charge a 400V battery; when the battery charging voltage is adjusted to 800V, the resonant inductance integrated transformer transformation ratio n=0.5 is adjusted, and the battery charging voltage can be adjusted to 0.5 without changing any other circuit parameters. 800V.

Since the forward conduction voltage of the silicon diode has a negative temperature coefficient, it cannot be directly used in parallel. The present embodiment is a high-low voltage compatible wireless power transmission system, which realizes natural current sharing and can be applied to wireless charging of high-power electric vehicles. the occasion.

Figure 4 is a parallel equivalent circuit diagram of the output of a resonant inductance integrated transformer at the receiving coil end of a high and low voltage compatible wireless power transmission system. As shown in FIG. 4 , a high-low voltage compatible wireless power transmission system in this embodiment is provided with two rectifier bridges at the VA end, a resonant inductance integrated transformer is added at the front stage of each rectifier bridge, and the output ends of the rectifier bridges are connected in parallel. The inverter circuit including the resonant inductor integrated transformer together charges the load battery.

Figure 5 is an equivalent circuit diagram of a high-low voltage compatible wireless power transmission system receiving coil end circuit resonant inductor integrated transformer output series equivalent circuit diagram. As shown in FIG. 5 , a high-low voltage compatible wireless power transmission system in this embodiment is provided with two rectifier bridges at the VA end, a resonant inductor integrated transformer is added at the front stage of each rectifier bridge, and the output ends of the rectifier bridges are connected in series, and the two rectifier bridges are connected in series. The inverter circuit including the resonant inductor integrated transformer together charges the load battery.

This embodiment is a high and low voltage compatible wireless power transmission system. When the voltage of the load rechargeable battery is 400V, the resonant inductance integrated transformer and the rectifier bridge are connected in parallel according to the output shown in Figure 4. At this time, each RIIT and the rectifier bridge are connected in parallel. The output voltage is equal to the total output voltage in parallel, and has the characteristics of voltage equalization and current equalization output; when the voltage of the load rechargeable battery is 800V, the resonant inductor integrated transformer and the rectifier bridge are connected in series according to the output shown in Figure 5. The sum of the output voltages of the two RIITs and the rectifier bridge is equal to the total output voltage in series. Therefore, this embodiment is a high-low voltage compatible wireless power transmission system, which can change the charging voltage of the WPT system by changing the connection mode of the resonant inductor integrated transformer, which is suitable for rechargeable batteries of different voltage levels without changing any parameters of the front-stage circuit. , reducing the manufacturing cost of the device.

FIG. 6 is a schematic diagram of the principle of realizing voltage equalization in series with the output of a resonant inductor integrated transformer in a receiving coil end circuit of a high and low voltage compatible wireless power transmission system. As shown in FIG. 6 , in a high-low voltage compatible wireless power transmission system in this embodiment, the voltage equalization process is as follows: the first voltage equalization auxiliary coil L _aux1 and the second voltage equalization auxiliary coil L _aux2 are respectively wound on the above two The resonant inductor is integrated on the magnetic core of the transformer to form a loop, and the difference in the flux linkage change rate in the two transformer cores is used to perform flux linkage compensation to achieve automatic voltage equalization output.

In an ideal situation, the parameters of the two-way resonant inductor integrated transformer and the series circuit of the rectifier bridge are exactly the same, the voltages of the two output capacitors are stable, and the average value of the currents I _C1 and I _C2 flowing into the two output capacitors is 0. However, due to the slight numerical deviation of the actual resonant inductor integrated transformer parameters, the average value of the currents I _C1 and I _C2 flowing into the two output capacitors is not 0, although the average value of the currents I _C1 and I _C2 flowing into the two output capacitors For small values, the voltages of the two output capacitors will become unstable, causing the voltage of one output capacitor to increase and the voltage of the other output capacitor to decrease. In this embodiment, a high-low voltage compatible wireless power transmission system uses an auxiliary coil wound on two magnetic cores of a resonant inductor integrated transformer, and the self-inductances of the auxiliary coils wound on the two magnetic cores are L _aux1 and L _{aux2 respectively} , The number of turns of the primary winding and the number of turns of the secondary winding of the two resonant inductor integrated transformers are respectively n ₁ and n ₂ , and the number of turns of the auxiliary coil is n ₃ . Ф ₁ , Ф _aux , Ф _rec1 and Ф _rec2 are the magnetic fluxes generated by the compensation network output current i ₁ , the compensation coil current i _aux , and the rectifier bridge currents i _rec1 and i _{rec2 respectively} . The auxiliary coil current is obtained by the following formula:

The formula for calculating the magnetic flux of the auxiliary coil is as follows:

Φ _rec1 =Φ ₁ -Φ _aux (5)

Φ _rec1 =Φ ₁ +Φ _aux (6)

When there is a deviation of the two output voltages, an induced current will be generated in the auxiliary coil according to the formula (1) in Embodiment 1. The induced current will generate a reverse magnetic flux in the magnetic core with large magnetic flux, and in the magnetic flux A forward magnetic flux is generated in the small magnetic core, thereby offsetting the unbalance of the output voltage and realizing automatic voltage equalization.

This embodiment is a high and low voltage compatible wireless power transmission system, which integrates the design and connection methods of resonant inductance, impedance matching, and transformers adapting to different load charging voltages, synthesizes resonant inductance, reduces the size of the device, and can be used without Under the condition of changing the circuit parameters, the impedance matching is realized, the circuit is allowed to work normally under different load charging voltages, and the output voltage equalization and output current equalization can be automatically realized, which has obvious application value.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and supplements can be made, and these improvements and supplements should also be considered as It is the protection scope of the present invention.

Claims (8)

1. A high and low voltage compatible wireless power transmission system, comprising a transmitting coil end and a receiving coil end; the transmitting coil end comprises a transmitting end inverter, a transmitting end LCC compensation network and a transmitting end coil connected in sequence; the receiving coil The terminal includes a receiving end coil and a receiving end LCC compensation network connected to each other, as well as a receiving end rectifier bridge and a rechargeable battery connected to each other; it is characterized in that: the receiving coil end also includes a resonant inductance integrated transformer, and the resonant inductance integrated transformer is once The winding is connected to the LCC compensation network at the receiving end, the secondary winding of the resonant inductance integrated transformer is connected to the rectifier bridge at the receiving end, and the leakage inductance L _r of the primary winding of the resonant inductance integrated transformer replaces the compensation inductance L _{f_va} of the LCC compensation network at the receiving end. The receiving coil end reaches the resonant state at the rated frequency, and is compatible with high and low voltage rechargeable batteries by changing the transformation ratio of the primary winding and the secondary winding of the resonant inductance integrated transformer. 2. A high-low voltage compatible wireless power transmission system according to claim 1, characterized in that it is compatible with charging of high-voltage rechargeable batteries and low-voltage rechargeable batteries, and the charging voltage of the high-voltage rechargeable battery is twice that of the low-voltage rechargeable battery , including two fixed ratio resonant inductance integrated transformers and two receiving end rectifier bridges, the two fixed ratio resonant inductance integrated transformer primary windings are connected in series to the receiving end LCC compensation network; charge the low-voltage rechargeable battery When charging the low-voltage rechargeable battery, the two fixed-ratio resonant inductance integrated transformer secondary windings are respectively connected to two receiving-end rectifier bridges and output in parallel to charge the low-voltage rechargeable battery; when charging the high-voltage rechargeable battery, the two fixed-ratio The secondary winding of the resonant inductance integrated transformer is respectively connected to two receiving end rectifier bridges and then output in series to charge the high-voltage rechargeable battery. 3. A high-voltage and low-voltage compatible wireless power transmission system according to claim 2, characterized in that: when charging the high-voltage rechargeable battery, it further comprises a first voltage equalizing auxiliary winding and a second equalizing auxiliary winding for assisting in realizing voltage equalization output. voltage auxiliary winding, the first voltage equalization auxiliary winding and the second voltage equalization auxiliary winding are respectively wound on the magnetic cores of the two fixed transformation ratio resonant inductance integrated transformers to form a loop, using the two fixed transformation ratios Compared with the resonant inductance of the integrated transformer core, the flux linkage is compensated for the difference in the flux linkage rate, and the automatic voltage equalization output is realized. 4 . The high and low voltage compatible wireless power transmission system according to claim 3 , wherein the self-inductance of the first voltage-sharing auxiliary winding is L _aux1 , and the self-inductance of the second voltage-balancing auxiliary winding is L _{aux2 . 5 .} , the number of turns of the primary winding and the number of turns of the secondary winding of the two fixed-ratio resonant inductance integrated transformers are n ₁ and n ₂ respectively, and the number of turns of the first and second equalizing auxiliary windings is n ₃ , Ф ₁ , Ф _aux , Ф _rec1 and Ф _rec2 are the output current i ₁ of the LCC compensation network at the receiving end, the primary winding current i _aux of the two fixed-ratio resonant inductor integrated transformers, and the current of the two receiving end rectifier bridges, respectively The magnetic flux generated by the excitation of i _rec1 and i _rec2 , the calculation formula of the current of the first voltage-sharing auxiliary winding and the second voltage-sharing auxiliary winding:

The magnetic flux calculation formulas of the first voltage-sharing auxiliary winding and the second voltage-sharing auxiliary winding are: Φ _rec1 =Φ ₁ -Φ _aux , Φ _rec1 =Φ ₁ +Φ _aux , when the output voltages of the two receiving end rectifier bridges in series have deviation When , an induced current is generated in the first and second equalizing auxiliary windings, a reverse magnetic flux is generated in the magnetic core of the resonant inductance integrated transformer with a large magnetic flux, and a resonant inductance integrated transformer with a small magnetic flux is generated. A forward magnetic flux is generated in the magnetic core, which offsets the unbalance of the output voltage of the two receiving end rectifier bridges in series, and realizes automatic voltage equalization output. 5 . The high-low voltage compatible wireless power transmission system according to claim 2 , wherein the charging voltage of the high-voltage rechargeable battery is 800V, and the charging voltage of the low-voltage rechargeable battery is 400V. 6 . 6. A method for manufacturing a resonant inductance integrated transformer of a high- and low-voltage compatible wireless power transmission system, which is used in the manufacture of a resonant inductance integrated transformer of a high- and low-voltage compatible wireless power transmission system according to any one of claims 1 to 5, wherein It is characterized by the following steps: S1. According to the charging voltage of the rechargeable battery, the transmission power of the system, the leakage inductance L _r of the primary winding of the resonant inductance integrated transformer, and the space limitation, perform preliminary calculations on the transformation ratio and output current of the resonant inductance integrated transformer, and select the winding wire diameter of the resonant inductance integrated transformer; S2. Select the material and shape of the magnetic core of the resonant inductor integrated transformer, and determine the transformation ratio of the resonant inductor integrated transformer; S3. Estimate the leakage inductance L _r of the primary winding of the resonant inductance integrated transformer, and calculate the power loss P _o of the resonant inductance integrated transformer. If the requirements are not met, step S2 is performed, otherwise, S5 is performed; S4. Make a prototype of a resonant inductor integrated transformer; S5, perform parameter test on the resonant inductance integrated transformer prototype, if unqualified, perform step S2, otherwise obtain the target resonant inductance integrated transformer. 7 . The method for manufacturing a resonant inductance integrated transformer of a high and low voltage compatible wireless power transmission system according to claim 6 , wherein the resonant inductance integrated transformer has a primary winding inductance L ₁ =μn ² A _e / _le , and the resonant inductance integrated Transformer primary winding leakage inductance

System transmission power

where μ is the magnetic permeability of the resonant inductor integrated transformer core, A _e is the effective cross-sectional area of the resonant inductor integrated transformer core, l _e is the magnetic circuit length of the resonant inductor integrated transformer, and k _riit is the coupling between the resonant inductor integrated transformer coils coefficient, M is the mutual inductance coefficient between the resonant inductor integrated transformer coils, L _ga , L _va , L _{f_ga} , L _{f_va} are the self-inductance of the transmitter coil, the receiver coil self-inductance, the transmitter LCC compensation network compensation inductance, the receiver LCC The compensation network compensates the inductance, ω is the resonant angular frequency, V _bus , V _bat1 , and V _bat2 are the DC bus voltage, the charging voltage of the high-voltage rechargeable battery and the charging voltage of the low-voltage rechargeable battery, respectively. 8 . The method for manufacturing a resonant inductance integrated transformer of a high and low voltage compatible wireless power transmission system according to claim 7 , wherein the magnetic core of the resonant inductance integrated transformer is an iron core. 9 .

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