Battery wireless charging system for high-order composite compensation network

Abstract

The invention discloses a battery wireless charging system for a high-order composite compensation network, provides the required first constant-current and second constant-voltage output in a batterycharging process, relates to the battery wireless charging technology and is suitable for the battery wireless charging occasions of electric automobiles and medical instruments. The system comprisesa high-frequency full-bridge inversion circuit, a primary side compensation network, a loose coupling transformer, a secondary side compensation network, a constant current-constant voltage switchingnetwork and a full-bridge rectification filter circuit. The system achieves the constant current output or constant voltage output irrelevant to a load at the specific frequency, achieves the switching of two modes through the constant current-constant voltage switching network placed at a secondary side, avoids the complex communication between the transmitting end and receiving end of the wireless charging system, simplifies the control, improves the reliability, achieves the approximate zero reactive loop current of a circuit and the soft switching of a switching device, and improves the efficiency, reduces the device stress. The output constant current and constant voltage values are not limited by the parameters of the loose coupling transformer, the design freedom of an energy transmission coil is improved, and the network transmission efficiency is improved.

Description

technical field [0001] The invention discloses a battery wireless charging system of a high-order composite compensation network, relates to battery wireless charging technology, and is suitable for battery wireless charging occasions such as electric vehicles and medical equipment. Background technique [0002] Wireless charging technology is convenient, safe and reliable because there is no electrical and mechanical connection between the power supply end and the power receiving end, so it has great application prospects. Battery charging usually includes two stages of constant current charging and constant voltage charging. Therefore, the wireless charging system needs to provide the battery with the required constant current and constant voltage output. [0003] The loosely coupled transformer used in the wireless charging system has a low coupling coefficient and a large leakage inductance, which inevitably generates reactive circulating current in the circuit, which in...

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Problems solved by technology

For example, the two basic topologies of SS / PS or PP / SP are composited through a switch, and the output of constant current and then constant voltage and full reactive power compensation can be realized through the control of the switch, and the above two composite structures are in different It has the same compensation parameters and resonant frequency in the working mode, which can reduce the number of compensation devices and switching switches. However, the mode switching switch is on the primary side. Therefore, the control of the mode switch needs to be carried out through the communication system between the transmitting end and the receiving end. Signal transmission, relatively complex control, low reliability

Based on the shortcomings of the composite structure of the primary side, the existing research puts the mode switching switch on the secondary side, such as SS / SP or PP / PS two composite structures, because the compensation frequency and parameters are not exactly the same, it is necessary to add additional compensation devices to Simultaneously realize constant current or constant voltage output and reactive power full compensation

The above composite structures are all based on four basic compensation structures. The coil design needs to consider the load situation, the coil design is limited, and the degree of freedom in parameter design is reduced.

[0005] Based on the problems existing in the above-mentioned composite topology, some studies have proposed that on the basis of bilateral LCC, by changing the operating frequency of the charging system, the output of constant current and then constant voltage and full reactive power compensation have been realized, but there are already relevant standards and specifications The working frequency of the charging system, if the working frequency exceeds the given frequency range, this method cannot be realized, and the communication between the primary side and the secondary side is still required to realize the change of the primary side frequency, which reduces the reliability of the system

[0006] From the above analysis, it can be seen that at present, the composite structure of secondary side mode switching, approximately zero reactive energy and constant current-constant voltage output can be realized at the same time, but there is still a problem that the parameters of the loosely coupled transformer outputting constant current or constant voltage are limited by the load condition. The method of realizing constant current and then constant voltage output and full reactive power compensation by changing the system operating frequency also has the problems of limited system operating frequency and reduced reliability.

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