CN103311902B - Over-current protection circuit of controller of motor of automobile - Google Patents

Abstract

The invention discloses an overcurrent protection circuit of an automobile motor controller, which comprises a trigger hold circuit connected to the output end of the trigger signal of the overcurrent judgment circuit, a reset circuit connected to the trigger hold circuit, and the input end of the reset circuit is also connected to the motor The reset signal output terminal of the main control chip is connected, and the output terminal of the trigger and hold circuit is also connected with the power device driving chip. The invention has the advantages of fast response speed, low cost and the like, and can provide protection for power devices in time.

Description

An automotive motor controller overcurrent protection circuit

technical field

The invention relates to the field of circuits, in particular to an overcurrent protection circuit for an automobile motor controller.

Background technique

The core components of motor controllers for new energy vehicles are power devices such as MOSFETs or IGBTs, and their development trend is high current and high power. The most common form of damage to power devices is overcurrent damage, so accurate measurement of the output current of the motor controller and reliable overcurrent protection based on accurate measurement are particularly important to ensure the safe operation of the motor controller.

At present, the current of the controller can be accurately measured by relying on high-precision current sensors, but the commonly used forms of over-current protection are over-current protection based on software detection or simple over-current protection based on over-saturation detection of integrated driver chips .

The reaction speed of overcurrent protection after software detection is slow, and the occurrence of overcurrent of power devices cannot be measured in time. It takes a long time to turn off the output signal after detection, and the time from overcurrent to damage of power devices is very short. , so software protection cannot provide overcurrent protection for power devices well. The oversaturation detection of the integrated driver chip can quickly detect and turn off quickly, but it cannot set the overcurrent protection value, and it cannot provide overcurrent protection for power devices well when the continuous large current does not cause oversaturation.

Contents of the invention

The technical problem to be solved by the present invention is: aiming at the above-mentioned problems existing in the prior art, the present invention provides an overcurrent protection circuit with short response time, low cost and good versatility. The present invention can provide power devices for motor controllers Fast hardware over-current protection, free to set the motor controller over-current protection current value, to ensure safe and efficient operation of the motor controller.

In order to achieve the above object, a kind of automobile motor controller overcurrent protection circuit of the present invention comprises a trigger holding circuit connected to the output terminal of the trigger signal of the overcurrent judgment circuit, a reset circuit connected to the trigger holding circuit, and the input terminal of the above reset circuit It is also connected to the reset signal output terminal of the motor main control chip, and the output terminal of the above trigger and hold circuit is also connected to the power device drive chip.

As a further improvement of the present invention, the above-mentioned reset circuit includes a resistor R9, a resistor R10, a capacitor C5, a capacitor C6, a diode D1, a diode D2, a resistor R11, and a resistor R12, wherein: the resistor R9 is connected to the reset signal output terminal of the motor main control chip ; After the resistor R9 and the capacitor C5 are connected in series, the capacitor C5 is connected to the positive pole of the diode D2, and the negative pole of the diode D2 is simultaneously connected to the positive pole of the diode D1, one end of the resistor R11, one end of the resistor R12, one end of the capacitor C6 and one of the trigger and hold circuits Input terminal; the other end of the resistor R11 and the cathode of the diode D1 are connected to the power supply VCC; the other end of the resistor R12 is connected to an output end of the trigger and hold circuit; one end of the capacitor C6 is connected to the cathode of the diode D2, and the other end is grounded; One end of R10 is connected between the capacitor C5 and the diode D2, and the other end is grounded.

Further, the above-mentioned trigger and hold circuit includes a comparator U2B, a comparator U2C, a comparator U2D and a voltage divider circuit, wherein: the non-inverting input terminal of the comparator U2B, the inverting input terminal of the comparator U2C, the inverting input terminal of the comparator U2D The input terminals are all connected to the voltage divider circuit; the positive input terminal of the comparator U2D is connected to the cathode of the above-mentioned diode D2; the inverting input terminal of the comparator U2B and the positive input terminal of the above-mentioned comparator U2C are connected to the output of the comparator U2D The output terminal of the comparator U2C is connected to the other end of the resistor R12; the output terminal of the comparator U2B is connected to the power device driver chip; the output terminal of the comparator U2D is also grounded through the capacitor C7; the power supply terminal of the comparator U2B is connected to a 12V power supply , the ground terminal is grounded; the output terminal of the trigger signal of the overcurrent judging circuit is simultaneously connected to the inverting input terminal of the above-mentioned comparator U2B and the non-inverting input terminal of the above-mentioned comparator U2C.

Further, the voltage dividing circuit is composed of capacitor C8, resistor R13, and resistor R14. The resistor R13 is connected to the power supply VCC, and the resistor R14 is grounded. The resistor R13 is connected in series with the resistor R14, and the capacitor C8 is connected in parallel to both ends of the resistor R14.

Further, the above trigger and hold circuit further includes a capacitor C9 and a resistor R15; the power supply terminal of the comparator U2B is also grounded through the capacitor C9; the output terminal of the comparator U2B is also connected to the power supply VCC through the resistor R15.

The working principle of the present invention is: when an overcurrent occurs, the overcurrent judgment circuit triggers the signal output terminal to output a low-level signal to report an error, and the power device driver chip receives the error signal to seal the output, and at the same time, FLTn makes the overcurrent protection circuit send a signal to the driver chip. Output a high-level signal and keep it, that is, keep the signal OE output from the over-current protection circuit to the driver chip at a high level, so that the output of the drive signal is blocked to ensure that the power device does not work until the main control chip outputs the RST signal to make the system reset.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

1. The invention has a fast response speed and can provide fast hardware overcurrent protection in time to ensure safe and efficient operation of the motor controller.

2. The present invention has simple structure and low cost.

Description of drawings

Fig. 1 is the circuit diagram of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

As shown in Figure 1, a kind of automobile motor controller overcurrent protection circuit of the present embodiment comprises the trigger hold circuit connected with the trigger signal output end of the overcurrent judgment circuit, the reset circuit connected with the trigger hold circuit, the above reset circuit The input terminal is also connected to the reset signal output terminal of the motor main control chip, and the output terminal of the above trigger and hold circuit is also connected to the power device drive chip.

The above trigger and hold circuit includes a comparator U2B, a comparator U2C, a comparator U2D and a voltage divider circuit, wherein: the non-inverting input terminal of the comparator U2B, the inverting input terminal of the comparator U2C, and the inverting input terminal of the comparator U2D Both are connected with the voltage divider circuit; the positive phase input terminal of the comparator U2D is connected with the cathode of the diode D2; the negative phase input terminal of the comparator U2B and the positive phase input terminal of the comparator U2C are connected with the output terminal of the comparator U2D; The output terminal of the comparator U2C is connected to the other end of the resistor R12; the output terminal of the comparator U2B is connected to the power device driver chip; the output terminal of the comparator U2D is also grounded through the capacitor C7; the power supply terminal of the comparator U2B is connected to the 12V power supply, and the ground terminal is grounded ; The trigger signal output terminal of the overcurrent judgment circuit is simultaneously connected to the inverting input terminal of the comparator U2B and the non-inverting input terminal of the comparator U2C. When over-current occurs, the over-current judgment circuit triggers the signal output terminal to output a low-level signal to report an error, and the power device driver chip receives the error signal to seal the output, and at the same time, FLTn makes the comparator U2B output a high-level signal to the driver chip and maintain it. Even if the signal OE output by the comparator U2B to the driver chip remains at a high level, the output of the driver signal is blocked to ensure that the power device does not work until the main control chip outputs the RST signal to reset the system.

The above reset circuit includes a resistor R9, a resistor R10, a capacitor C5, a capacitor C6, a diode D1, a diode D2, a resistor R11, and a resistor R12, wherein: the resistor R9 is connected to the reset signal output terminal of the motor main control chip; the resistor R9 and the capacitor C5 are connected in series Finally, the capacitor C5 is connected to the positive pole of the diode D2, and the negative pole of the diode D2 is connected to the positive pole of the diode D1, one end of the resistor R11, one end of the resistor R12, one end of the capacitor C6 and an input end of the trigger and hold circuit; the other end of the resistor R11 One end and the cathode of the diode D1 are connected to the power supply VCC; the other end of the resistor R12 is connected to an output end of the trigger and hold circuit; one end of the capacitor C6 is connected to the cathode of the diode D2, and the other end is grounded; one end of the resistor R10 is connected to the capacitor C5 and diode D2, the other end is grounded. One end of the resistor R12 is connected to the cathode of the diode D2, and the other end is connected to the output end of the comparator U2C.

The voltage dividing circuit is composed of capacitor C8, resistor R13, and resistor R14. The resistor R13 is connected to the power supply VCC, and the resistor R14 is grounded.

The above trigger and hold circuit also includes a capacitor C9 and a resistor R15; the power terminal of the comparator U2B is also grounded through the capacitor C9; the output terminal of the comparator U2B is also connected to the power supply VCC through the resistor R15.

The above are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions under the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those skilled in the art, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims (4)

1. an over-current protection circuit of controller of motor of automobile, it is characterized in that, comprise the triggering holding circuit be connected with overcurrent judgment circuit triggering signal output, the reset circuit be connected with triggering holding circuit, the input of described reset circuit is also connected with the reset signal output of motor main control chip, and the output of described triggering holding circuit is also connected with power device driving chip;

Described reset circuit comprises resistance R9, resistance R10, electric capacity C5, electric capacity C6, diode D1, diode D2, resistance R11, resistance R12, wherein: resistance R9 is connected to the reset signal output of motor main control chip; After resistance R9 and electric capacity C5 connects, electric capacity C5 is connected to the positive pole of diode D2, and the negative pole of diode D2 is connected to the positive pole of diode D1, one end of resistance R11, one end of resistance R12, one end of electric capacity C6 simultaneously and triggers an input of holding circuit; The other end of described resistance R11 and the negative pole of diode D1 are all connected on power supply VCC; The other end of described resistance R12 is connected with the output triggering holding circuit; One end of described electric capacity C6 connects the negative pole of diode D2, other end ground connection; Described resistance R10 one end is connected between electric capacity C5 and diode D2, other end ground connection.

2. a kind of over-current protection circuit of controller of motor of automobile according to claim 1, it is characterized in that, described triggering holding circuit comprises comparator U2B, comparator U2C, a comparator U2D and bleeder circuit, wherein: the reverse input end of the normal phase input end of described comparator U2B, the inverting input of comparator U2C, comparator U2D is all connected with bleeder circuit; The normal phase input end of described comparator U2D is connected with the negative pole of described diode D2; The inverting input of described comparator U2B is all connected with the output of comparator U2D with the normal phase input end of described comparator U2C; The output of described comparator U2C is connected with the other end of resistance R12; The output of described comparator U2B is connected with power device driving chip; The output of described comparator U2D is also by electric capacity C7 ground connection; Described comparator U2B power end connects 12V power supply, earth terminal ground connection; Described overcurrent judgment circuit triggering signal output is connected to the inverting input of described comparator U2B and the normal phase input end of described comparator U2C simultaneously.

3. a kind of over-current protection circuit of controller of motor of automobile according to claim 2; it is characterized in that; described bleeder circuit is made up of electric capacity C8, resistance R13, resistance R14; resistance R13 connects power supply VCC, resistance R14 ground connection; resistance R13 connects with resistance R14, and electric capacity C8 is connected in parallel on resistance R14 two ends.

4. a kind of over-current protection circuit of controller of motor of automobile according to Claims 2 or 3, is characterized in that, described triggering holding circuit also comprises electric capacity C9 and resistance R15; The power end of described comparator U2B is also by electric capacity C9 ground connection; The output of described comparator U2B also connects power supply VCC by resistance R15.