Over-current protection method and circuit for a DC inverter

1. An over-current protection method for a DC Inverter, wherein said over-current protection method comprises:

sampling output currents from a power module to form a sampled signal;

amplifying with a plurality of magnification factors and low-pass filtering said sampling signal to generate a first over-current signal and a second over-current signal, wherein a first magnification factor, on the basis of which said first over-current signal is generated, is pertinent to an over-current threshold of said power module, and a second magnification factor, on the basis of which said second over-current signal is generated, is pertinent to an over-current threshold of a motor;

generating a first interrupt trigger signal based on said first over-current signal;

comparing said second over-current signal with a reference voltage corresponding to said over-current threshold of the motor, with a comparison result being a second interrupt trigger signal;

controlling said power module based on said first interrupt trigger signal; and

controlling said motor based on said second interrupt trigger signal.

2. The over-current protection method as defined in claim 1 , wherein said over-current threshold of the motor is dynamically adjustable.

3. An over-current protection circuit for a DC Inverter, wherein said over-current protection circuit comprises:

a sampling unit for sampling output currents from a power module to form a sampling signal;

a signal-processing unit for amplifying with a plurality of magnification factors and low-pass filtering said sampling signal to generate a first over-current signal and a second over-current signal, wherein a first magnification factor, on the basis of which said first over-current signal is generated, is pertinent to an over-current threshold of said power module, and a second magnification factor, on the basis of which said second over-current signal is generated, is pertinent to an over-current threshold of a motor;

a signal-generating unit for generating a first interrupt trigger signal based on said first over-current signal;

a comparison unit for comparing said second over-current signal with a reference voltage corresponding to said over-current threshold of the motor, with a comparison result being a second interrupt trigger signal; and

a control unit for controlling said power module based on said first interrupt trigger signal, and said motor based on said second interrupt trigger signal.

4. The over-current protection circuit as defined in claim 3 , wherein said over-current threshold of the motor is obtained via digital-to-analog conversion after calculation by said control unit on the basis of specifications and running states of said motor.

5. The over-current protection circuit as defined in claim 4 , wherein a digital-to-analog converter used for said digital-to-analog conversion is comprised inside said control unit.

6. The over-current circuit as defined in claim 3 , wherein said comparison unit is comprised inside said control unit.

7. The over-current circuit as defined in claim 3 , wherein dynamic adjustability of said over-current threshold of the motor is realized by a duty ratio generated from a pulse-width modulation output of said control unit together with a resistance-capacitance low-pass filter circuit.

8. The over-current protection circuit as defined in claim 3 , wherein said sampling unit comprises a sampling resistance.

9. The over-current protection circuit as defined in claim 3 , wherein said signal-processing unit comprises an operational amplifier and a low-pass filter, and said operational amplifier is a non-inverting amplifier.

10. The over-current circuit as defined in claim 3 , wherein said signal-generating unit is said power module.