Method and device for determining over-current of inverter

Abstract

The invention discloses a method for determining the over-current of an inverter. The method comprises the steps that a current detection circuit detects the current of the inverter and sends a current detection result to a microprocessor; the microprocessor compares a detected current peak with a preset current threshold, stops normal outputting of sinusoidal pulse width modulation (SPWM) signals if the current peak is larger than or equal to the current threshold and outputs the SPWM signals equivalent to low-amplitude sinusoidal wave signals to the inverter; a voltage detection circuit detects the output voltage of the inverter and sends a voltage detection result to the microprocessor; and the microprocessor compares a detected voltage effective value with a preset voltage threshold and determines that the inverter is short-circuited if the voltage effective value is smaller than the voltage threshold, and the over-current occurs to the inverter due to impact loads. The invention further discloses a device for implementing the method. By means of the method and the device, whether the over-current of the inverter is caused by impact loads or short-circuit can be distinguished accurately.

Description

technical field [0001] The invention relates to a method and a device for judging the overcurrent of an inverter. Background technique [0002] Short-circuit protection is a crucial issue in the development of inverter power supply, which is related to the operation safety of the entire device. The difficulty of short-circuit protection technology is that it is easy to confuse the large current caused by an impact load (such as a sudden power adapter or a light bulb, etc.) with the real short-circuit current, so that a wrong judgment can be made. This kind of misjudgment is likely to cause two consequences: first, the real short circuit is missed, resulting in instantaneous damage to the device; second, the impact load current is misjudged as a short circuit current, and the device will be turned off by mistake. broken. In addition, the existing inverter short-circuit protection circuit mainly relies on hardware implementation, resulting in high implementation cost. Cont...

AI Technical Summary

Problems solved by technology

The difficulty of short-circuit protection technology is that it is easy to confuse the large current caused by the impact load (such as sudden power adapter or light bulb, etc.) with the real short-circuit current, so that a wrong judgment can be made

This kind of misjudgment is likely to cause two consequences: first, the real short circuit is missed, resulting in instantaneous damage to the device; second, the impact load current is misjudged as a short circuit current, and the device will be turned off by mistake. broken

In addition, the existing inverter short-circuit protection circuit mainly relies on hardware implementation, resulting in high implementation cost

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