Over-current detection system of inverter circuit and method of over-current detection system

Abstract

The invention relates to an over-current detection system of an inverter circuit and a method of the over-current detection system. The method comprises the steps of: collecting a current signal of the inverter circuit by a detection circuit, converting the current signal into a voltage signal to output to a microcontroller; if the inverter circuit is in a short circuit or overloaded, receiving a series of spike pulse signals by the microcontroller, wherein a timer and a counter for recording the quality of the spike pulse signals are arranged inside the microcontroller; if the microcontroller detects that a counting variable of the counter within timing time is greater than or equal to an upper limit value of counting set in advance, judging that the inverter circuit is in the short circuit or overloaded, then transmitting a terminating signal to a drive circuit by the microcontroller, and closing a PWM (pulse-width modulation) signal. The detection circuit disclosed by the invention is simple; the hardware cost is low, and a software testing method is simple and convenient; meanwhile, the detection method provided by the invention is strong in instantaneity; the short circuit or overload state of the inverter circuit can be immediately detected, so as to close the PWM signal, and the inverter circuit can be efficiently and timely protected.

Description

technical field [0001] The invention relates to the technical field of inverter circuits, in particular to an inverter circuit overcurrent detection system and method thereof. Background technique [0002] The inverter circuit is a circuit structure device that converts direct current into alternating current, and has been widely used. A general inverter circuit includes a DC voltage source and a switching element driven by a pulse width modulation (PWM) control signal connected to an output smoothing capacitor to generate a desired output voltage. However, in order to ensure the service life of the inverter circuit, it is necessary to prevent the short circuit or overload of the inverter circuit from causing damage to the internal components of the inverter circuit, especially the switching devices. At present, the short circuit or overload protection circuit of the inverter circuit is generally used to protect the inverter circuit. The traditional short-circuit or overlo...

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Problems solved by technology

This method requires a complex circuit to limit the short-circuit current, and the software test also has a certain complexity

Moreover, this method needs to go through several power frequency cycles to protect the switching devices of the inverter circuit. In this way, the switching devices inside the inverter circuit must withstand the damage of several power frequency cycles when they are short-circuited or overloaded.

The traditional method for short-circuit or overload protection of the inverter circuit is bulky, the software test is complicated, the cost is high, and the effect is not ideal

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