A full bridge protection method, circuit, controller and wireless power supply system

Abstract

The invention discloses a full bridge protection method and circuit, a controller and a wireless power supply system. The method comprises the steps of after a first switching group is turned off, acquiring the voltage V2 of the second end of a first switching tube; judging whether V2 / V1 is less than a preset value or not, if yes, controlling a second switching group to be turned on, and if not, repeating the above process, wherein V1 is a rated value of direct current voltage. Therefore, according to the method, after the first switching group is turned off, the second switching group is not immediately turned on or is not turned on after a fixed period of dead time, but whether a ratio of the voltage V2 of the second end of the first switching tube to the rated value of the direct current voltage is less than the preset value or not is judged, and the second switching group is controlled to be turned on only when the ratio of the voltage V2 of the second end of the first switching tube to the rated value of the direct current voltage is less than the preset value, so that the current which is generated due to the existence of the voltage V2 and is carried by a third switching tube is greatly reduced when the third switching tube is turned on, and the safety performance, stability and reliability of a full bridge are improved.

Description

Technical field [0001] The present invention relates to the technical field of full bridge protection, in particular to a full bridge protection method, circuit, controller and wireless power supply system. Background technique [0002] In recent years, wireless power supply technology has been greatly developed. The current high-power wireless power supply transmitter mainly uses a full bridge to supply power to the coil. For details, please refer to figure 1 , figure 1 It is a schematic diagram of the structure of the transmitting end of a wireless power supply system in the prior art. V1 is a DC voltage, and the two switch tubes on the diagonal are a group. Assume that D1 and D4 are the first switch group, and D2 and D3 are In the second switch group, during normal operation, the switch tubes of the first switch group are turned on, and are turned off after a fixed duty cycle. After a fixed dead time, the switch tubes of the second switch group are turned on again, and then pas...

AI Technical Summary

Problems solved by technology

[0003] In practical applications, when the first switch group is turned on, V1=V2, V3=0, when the first switch group is turned off, in theory, V2 should quickly drop to 0, but because there is a transmitting coil, the transmitting coil will Freewheeling, which leads to a slow time for V2 to drop to 0; in addition, the farther the load is from the transmitting coil, the longer the freewheeling time, further slowing down the speed of V2 reduction

If V2 is not reduced to a small value within the fixed dead time, it may cause V2 to be directly grounded when the second switch group is turned on, and a large current will be generated on D3, which will cause D3 to explode, and the first switch group will conduct again. After passing through, it will cause the D1 tube to explode, which greatly reduces the safety performance, stability and reliability of the whole bridge

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