Electric car wireless charging system coil protection circuit and method

Abstract

The invention discloses an electric car wireless charging system coil protection circuit and method. The circuit comprises a coil current detecting circuit which is used for acquiring a current in a coil to be detected, converting the current into a DC voltage and outputting the DC voltage through a first output terminal, a second output terminal which is used for outputting a voltage of a DC voltage proportionally stepped down, a reference voltage generating circuit for generating a reference voltage and inputting the reference voltage to a comparison output circuit, the comparison output circuit which is used for comparing the DC voltage with the reference voltage and outputting an alarm signal if the DC voltage is higher than the reference voltage, and a processor which is used for periodically acquiring the voltage outputted by the second output terminal and adjusting the reference voltage generating circuit according to the currently acquired voltage to make the difference betweenthe generated reference voltage and the currently acquired voltage to be a preset voltage value. The reliability and accuracy of the alarm of the present invention are high, and the alarm triggeringtime is short compared to the prior art in some cases.

Description

technical field [0001] The invention relates to the technical field of wireless charging protection, in particular to a coil protection circuit and method for a wireless charging system of an electric vehicle. Background technique [0002] Wireless power supply applications have gradually emerged, and there are more and more products that are close to the daily life of ordinary people. Because the wireless power supply is a resonance method, the voltage and current are particularly large during operation. The coil part is exposed for a long time, and the risk of damage to the short circuit is also higher. Therefore, reliable circuit protection is required. [0003] Conventional circuit protection is to set a threshold voltage. When the external short circuit of the coil or the overcurrent and overload signal voltage exceeds the set threshold voltage, the protection circuit will work, output a signal, and control the shutdown of the equipment. This solution needs the signa...

AI Technical Summary

Problems solved by technology

This solution needs the signal to exceed the preset threshold to trigger the alarm. If the preset threshold is set too high, it will take a long time from overload to alarm; in addition, in practical applications, the time for the signal to exceed the preset threshold is not Certainly, if the signal exceeds the preset threshold after a long time, it indicates that the rate of change of the signal is very slow. In this case, the coil is generally not short-circuited or overloaded, so the alarm at this time is actually a misjudgment and the reliability is low.

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