CN110176855A - A kind of active clamp protection circuit of the IGBT driving based on HCPL-316J - Google Patents

Abstract

The invention discloses an active clamp protection circuit driven by an IGBT based on HCPL-316J, which relates to the field of integrated circuits and includes a control module, an HCPL-316J drive chip, an IGBT overcurrent protection circuit and an active clamp protection circuit. The HCPL‑316J driver chip has an overcurrent soft shutdown function, and its internal input and output have optocoupler isolation, which reduces the number of components in the driving circuit and improves system stability and safety; at the same time, the collector of the IGBT and An active clamping protection circuit is added between the gate, the collector of the IGBT and the HCPL-316J drive output Vout (base stage of the push-pull circuit) to ensure that when the IGBT is turned off, due to the The spike voltage generated by the stray inductance will not damage the IGBT.

Description

An active clamp protection circuit driven by IGBT based on HCPL-316J

technical field

The invention relates to the field of integrated circuits, in particular to an active clamp protection circuit driven by an IGBT based on HCPL-316J.

Background technique

IGBT (Insulated Gate Bipolar Transistor), Insulated Gate Bipolar Transistor, is a composite fully-controlled voltage-driven power semiconductor device composed of BJT (Bipolar Transistor) and MOSFET (Insulated Gate Field Effect Transistor).

The saturation voltage of BJT is reduced, the current carrying density is large, but the driving power is large; the driving power of MOSFET is small, the switching speed is fast, but the conduction voltage drop is large, and the current carrying density is small. IGBT combines the advantages of the above two devices, and the drive The power is small and the saturation pressure is reduced. It is very suitable for the field of converter systems with mainstream voltages of 600V and above. It is the most rapidly developing power electronic device at present, and the drive and protection of IGBT are the most important.

Most of the current IGBT drive circuits are direct drive or isolation drive, which requires a large margin and a large system, which cannot completely resist external interference and various failure problems caused by its own system, and the system stability and reliability are poor.

Contents of the invention

The purpose of the present invention is to provide an active clamping protection circuit driven by an IGBT based on HCPL-316J. The HCPL-316J driver chip used has an overcurrent soft shutdown function, and has an optocoupler isolation between its internal input and output. While reducing the number of components in the drive circuit, improve system stability and safety; at the same time, between the collector and gate of the IGBT, between the collector of the IGBT and the HCPL-316J drive output Vout (the base of the push-pull circuit) An active clamp protection circuit is added in between to ensure that the peak voltage generated by the stray inductance in the inverter circuit will not damage the IGBT when the IGBT is turned off.

An active clamp protection circuit driven by an IGBT based on HCPL-316J, including a control module, an HCPL-316J drive chip, an IGBT overcurrent protection circuit and an active clamp protection circuit;

The control module includes a DSP unit, the PWM output pin of the DSP unit is connected to the PWM output terminal, the PWM wave is output, the reset signal and the FAULT signal are connected to the IO port of the DSP unit, and the reset signal and the fault signal are provided for the HCPL-316J chip respectively. For the return interface, a resistor is connected to the PWM output pin of the DSP unit to prevent the IGBT overcurrent protection circuit from being misconducted during the DSP initialization process, and a diode is connected in series to the FAULT signal connection line;

The HCPL-316J driver chip is combined with the DSP to realize the driving of the IGBT overcurrent protection circuit. The input side power supply of the HCPL-316J driver chip is shared with the DSP unit, and its output side is connected to the DC/DC module power supply. The output voltage is +15V and -8V, and connect several bypass capacitors between the +15V power supply terminal, -8V power supply terminal and ground;

The IGBT overcurrent protection circuit is connected to the DESAT end of the HCPL-316J driver chip, and two FR107 fast recovery diodes and two 1N4148 diodes are connected to the DESAT end as clamping diodes to protect the HCPL-316J chip;

The active clamping protection circuit is connected to the Vout end of the HCPL-316J driver chip, and the active clamping protection circuit is connected in parallel with an 18V bidirectional TVS tube between the gate and the emitter, through the TVS tube and two ES1D fast recovery rectifier diodes Connect the gate and collector of the IGBT, and connect the collector of the IGBT to the base of the push-pull circuit.

Preferably, the HCPL-316J drive chip contains an optocoupler isolation circuit and a push-pull drive circuit. After the DSP outputs a PWM signal to the HCPL-316J drive chip, the PWM signal passes through the optocoupler isolation circuit and then the push-pull drive circuit for power Amplify and drive the IGBT overcurrent protection circuit.

Preferably, when the IGBT overcurrent protection circuit is driven, the DSP unit only needs one IO port as a fault return interface.

Preferably, two FR107 fast recovery diodes are connected in series, and two 1N4148 diodes are connected in parallel.

Preferably, five bypass capacitors are connected between the +15V power supply terminal of the DC/DC module power supply and the ground, and the five bypass capacitors are connected in parallel with each other, and the -8V power supply terminal of the DC/DC module power supply and the ground Five bypass capacitors are also connected between them, and the five bypass capacitors are also connected in parallel with each other.

Preferably, the threshold voltage of the TVS tube is higher than its DC bus voltage and lower than the safety voltage of the IGBT overcurrent protection circuit.

The advantages of the present invention are: the HCPL-316J driver chip used has an over-current soft shutdown function, and its internal input and output have optocoupler isolation, which improves system stability and safety while reducing the number of components in the driver circuit ; At the same time, an active clamp protection circuit is added between the collector and the gate of the IGBT, between the collector of the IGBT and the HCPL-316J drive output Vout (base stage of the push-pull circuit), to ensure that the IGBT is turned off at the moment , the spike voltage generated by the stray inductance in the inverter circuit will not damage the IGBT.

Description of drawings

Fig. 1 is the total circuit schematic diagram of the present invention;

Fig. 2 is circuit protection working principle diagram among the present invention;

Fig. 3 is a control module circuit diagram in the present invention;

Fig. 4 is HCPL-316J driver chip and peripheral circuit diagram among the present invention;

Fig. 5 is IGBT overcurrent protection circuit diagram among the present invention;

Fig. 6 is an active clamp protection circuit diagram in the present invention;

Detailed ways

In order to make the technical means, creative features, goals and effects achieved by the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments.

As shown in Figures 1 to 6, an active clamp protection circuit driven by an IGBT based on HCPL-316J includes a control module, an HCPL-316J drive chip, an IGBT overcurrent protection circuit and an active clamp protection circuit;

The control module includes a DSP unit, the PWM output pin of the DSP unit is connected to the PWM output terminal, the PWM wave is output, the reset signal and the FAULT signal are connected to the IO port of the DSP unit, and the reset signal and the fault signal are provided for the HCPL-316J chip respectively. Backhaul interface, the PWM output pin of the DSP unit is connected to a resistor to prevent the IGBT overcurrent protection circuit from being misconducted during the DSP initialization process, and a diode is connected in series to the FAULT signal connection line; the control module generally refers to DSP, FPGA or a combination of the two The unit is mainly used for sending PWM pulses, HCPL-316J chip reset and fault feedback. The present invention selects the DSP unit as the control module, and the specific connections are as shown in Figure 3. PWM4 is connected to the PWM output pin of the DSP unit to output the PWM wave; the reset signal is directly connected to the IO port of the DSP unit to provide for the HCPL-316J chip. Reset signal; FAULT signal is connected to the IO port of the DSP unit as a fault return interface. The pull-down resistor IR3 is to prevent the IGBT overcurrent protection circuit from being misconducted during the initialization process of the DSP unit. The ID1 diode is added to consider that when driving multiple IGBT overcurrent protection circuits, only one IO port is needed as a fault return interface.

The HCPL-316J driver chip is combined with the DSP to realize the driving of the IGBT overcurrent protection circuit. The input side power supply of the HCPL-316J driver chip is shared with the DSP unit, and its output side is connected to the DC/DC module power supply. The output voltage is +15V and -8V, and add some bypass capacitors between +15V power supply terminal, -8V power supply terminal and ground; HCPL-316J drive chip is an optocoupler isolation drive device, which integrates collector-emitter voltage undersaturation detection circuit inside And fault feedback circuit, with over-current soft shutdown and optocoupler isolation function, compatible with COMS/TTL level. Combining with the DSP unit can realize the driving of the IGBT overcurrent protection circuit, making the IGBT overcurrent protection circuit more compact and lower in cost. DSP unit outputs PWM signal, connects to HCPL-316J through PWM input module, passes through its internal optocoupler isolation circuit, and then performs power amplification through push-pull drive circuit to drive IGBT overcurrent protection circuit.

As shown in Figure 4, the HCPL-316J drive chip is an optocoupler isolation drive device, and its input side power supply can be shared with the DSP unit. In the present invention, its output side power supply chooses Jinshengyang's IGBT driver dedicated DC/DC module power supply. The output voltages are +15V/120mA and -8V/120mA. It adopts an asymmetrical voltage output form inside to reduce the driving loss of the IGBT overcurrent protection circuit. It also has output short circuit protection and self-recovery capabilities. A large number of bypass capacitors are added between +15V, -8V and ground to reduce ripple noise and provide a large amount of transient current during switching transitions to ensure the effective conduction of the IGBT overcurrent protection circuit. ,

The IGBT overcurrent protection circuit is connected to the DESAT end of the HCPL-316J driver chip, and two FR107 fast recovery diodes and two 1N4148 diodes are connected to the DESAT end as clamping diodes to protect the HCPL-316J chip; when the IGBT overcurrent When the protection circuit is turned on, overcurrent occurs. Due to the characteristics of the IGBT overcurrent protection circuit, U _CE (the voltage between the collector and emitter of the circuit) rises sharply. The fast recovery diodes ID4 and ID5 detect the value of U _CE . If If the set U _CE protection voltage is exceeded, the input voltage of the DESAT terminal is greater than 7V, the desaturation protection circuit starts to work, the HCPL-316J locks the low-level output, turns off the IGBT over-current protection circuit, and at the same time, the FAULT terminal outputs a low level to the DSP unit. The threshold voltage of V _DESAT (DESAT port voltage) is 7V, V _DESAT ＝U _CE +nU _D (UD is the voltage drop of the fast recovery diode, _n is the number of fast recovery diodes), so U _CE ＝V _{DESAT -nU D} , the value of U _CE can be adjusted by increasing or decreasing the number of fast recovery diodes. In the present invention, two FR107 fast recovery diodes are selected; two 1N4148 diodes are used as clamping diodes to protect the HCPL-316J chip. The circuit diagram is shown in Figure 5 below.

The active clamping protection circuit is connected to the Vout end of the HCPL-316J driver chip, and the active clamping protection circuit is connected in parallel with an 18V bidirectional TVS tube between the gate and the emitter, through the TVS tube and two ES1D fast recovery rectifier diodes Connect the gate and collector of the IGBT overcurrent protection circuit, and connect the collector of the IGBT overcurrent protection circuit with the base of the push-pull circuit.

As shown in Figure 6, since the gate withstand voltage of the IGBT overcurrent protection circuit is about ±20V, it is easy to break down and cause damage if it exceeds this value. In the present invention, an 18V bidirectional TVS transistor is connected in parallel between the gate and the emitter. ID6, which prevents this. There is a high voltage on the collector of the IGBT over-current protection circuit. Once the gate level of the IGBT over-current protection circuit is suspended, the IGBT over-current protection may be caused by the action of the Miller capacitor C _GE of the IGBT over-current protection circuit. The circuit is mis-conducted and the IGBT overcurrent protection circuit is burned out. The presence of the IR5 resistor in the figure can provide a release channel for the Miller capacitor C _GE to prevent misconduct.

The gate and collector of the IGBT overcurrent protection circuit, the collector of the IGBT overcurrent protection circuit and the base of the push-pull circuit are established through the TVS tube and two ES1D fast recovery rectifier diodes ID10 and ID11. When U When the _CE voltage is too high, the TVS tube is broken down. Since the turn-off transistor in the push-pull circuit is in the open state at this time, most of the current flowing into the TVS tube enters the base stage of the push-pull circuit, and a small part enters the IGBT overcurrent protection circuit. gate pole. The part that enters the gate of the IGBT overcurrent protection circuit can realize the fast response of the IGBT overcurrent protection circuit; the part that enters the base stage of the push-pull circuit makes the turn-off triode still open and bypasses the TVS tube current .

For the selection of TVS tubes, the threshold voltage needs to be higher than the DC bus voltage and lower than the safety voltage of the IGBT overcurrent protection circuit. According to experience, TVS tubes are generally selected in series, and the threshold voltage V _TH after series connection is 1.1 times the bus voltage. The bus voltage V _DC of the present invention is 600V, and three SMBJ220CA are selected to be connected in series.

The HCPL-316J drive chip contains an optocoupler isolation circuit and a push-pull drive circuit. After the DSP outputs a PWM signal to the HCPL-316J drive chip, the PWM signal passes through the optocoupler isolation circuit, and then the power is amplified by the push-pull drive circuit to drive IGBT overcurrent protection circuit. The push-pull drive circuit plays the role of amplifying the PWM signal.

When the IGBT overcurrent protection circuit is driven, the DSP unit only needs one IO port as a fault return interface. Save wires and interfaces.

The two FR107 fast recovery diodes are connected in series, and the two 1N4148 diodes are connected in parallel.

5 bypass capacitors are connected between the +15V power supply terminal of the DC/DC module power supply and the ground, and the 5 bypass capacitors are connected in parallel with each other, and the -8V power supply terminal of the DC/DC module power supply is also connected to the ground Five bypass capacitors are also connected in parallel with each other. While reducing ripple noise, it provides a large amount of transient current during the switching process to ensure the effective conduction of the IGBT over-current protection circuit.

The threshold voltage of the TVS tube is higher than its DC bus voltage and lower than the safety voltage of the IGBT overcurrent protection circuit. Ensure the sensitivity of the TVS tube.

Specific implementation and principle

The present invention selects the DSP unit as the control module, and the specific connections are as shown in Figure 3. PWM4 is connected to the PWM output pin of the DSP unit to output the PWM wave; the reset signal is directly connected to the IO port of the DSP unit to provide for the HCPL-316J chip. Reset signal; FAULT signal is connected to the IO port of the DSP unit as a fault return interface. The pull-down resistor IR3 is to prevent the IGBT overcurrent protection circuit from being misconducted during the initialization process of the DSP unit. The ID1 diode is added to consider that when driving multiple IGBT overcurrent protection circuits, only one IO port is needed as a fault return interface;

And choose HCPL-316J driver chip, HCPL-316J driver chip is an optocoupler isolation drive device, which integrates collector-emitter voltage undersaturation detection circuit and fault feedback circuit, with over-current soft shutdown and optocoupler isolation function, Compatible with COMS/TTL level. Combining with the DSP unit can realize the driving of the IGBT overcurrent protection circuit, making the IGBT overcurrent protection circuit more compact and lower in cost. The DSP unit outputs the PWM signal, which is connected to the HCPL-316J through the PWM input module, through its internal optocoupler isolation circuit, and then through the push-pull drive circuit for power amplification to drive the IGBT over-current protection circuit;

As shown in Figure 4, the HCPL-316J drive chip is an optocoupler isolation drive device, and its input side power supply can be shared with the DSP unit. In the present invention, its output side power supply chooses Jinshengyang's IGBT driver dedicated DC/DC module power supply. The output voltage is +15V/120mA and -8V/120mA. It adopts an asymmetrical voltage output form inside to reduce the driving loss of the IGBT overcurrent protection circuit, and has output short-circuit protection and self-recovery capabilities. A large number of bypass capacitors are added between +15V, -8V and ground to reduce ripple noise and provide a large amount of transient current during switching transitions to ensure the effective conduction of the IGBT overcurrent protection circuit. ,

When an overcurrent occurs when the IGBT overcurrent protection circuit is turned on, due to the characteristics of the IGBT overcurrent protection circuit, U _CE (the voltage between the collector and emitter of the circuit) rises sharply, and the fast recovery diodes ID4 and ID5 detect U _CE If the value exceeds the set U _CE protection voltage, the input voltage of the DESAT terminal is greater than 7V, the desaturation protection circuit starts to work, the HCPL-316J locks the low-level output, turns off the IGBT over-current protection circuit, and at the same time the FAULT terminal outputs low level to the DSP unit. The threshold voltage of V _DESAT (DESAT port voltage) is 7V, V _DESAT ＝U _CE +nU _D (UD is the voltage drop of the fast recovery diode, _n is the number of fast recovery diodes), so U _CE ＝V _{DESAT -nU D} , the value of U _CE can be adjusted by increasing or decreasing the number of fast recovery diodes. In the present invention, two FR107 fast recovery diodes are selected; two 1N4148 diodes are used as clamping diodes to protect the HCPL-316J chip. The circuit diagram is shown in Figure 5 below.

And as shown in Figure 6, since the gate withstand voltage of the IGBT overcurrent protection circuit is about ±20V, it is easy to break down and cause damage if it exceeds this value. In the present invention, an 18V bidirectional TVS is connected in parallel between the gate and the emitter. Pipe ID6, can prevent this. There is a high voltage on the collector of the IGBT over-current protection circuit. Once the gate level of the IGBT over-current protection circuit is suspended, the IGBT over-current protection may be caused by the action of the Miller capacitor C _GE of the IGBT over-current protection circuit. The circuit is misconducted and burns out the IGBT overcurrent protection circuit. The existence of the IR5 resistor in the figure can provide a release channel for the Miller capacitor C _GE to prevent misconduct;

The gate and collector of the IGBT overcurrent protection circuit, the collector of the IGBT overcurrent protection circuit and the base of the push-pull circuit are established through the TVS tube and two ES1D fast recovery rectifier diodes ID10 and ID11. When U When the _CE voltage is too high, the TVS tube is broken down. Since the turn-off transistor in the push-pull circuit is in the open state at this time, most of the current flowing into the TVS tube enters the base stage of the push-pull circuit, and a small part enters the IGBT overcurrent protection circuit. gate pole. The part that enters the gate of the IGBT overcurrent protection circuit can realize the fast response of the IGBT overcurrent protection circuit; the part that enters the base stage of the push-pull circuit makes the turn-off triode still open and bypasses the TVS tube current ;

For the selection of TVS tubes, the threshold voltage needs to be higher than the DC bus voltage and lower than the safety voltage of the IGBT overcurrent protection circuit. According to experience, TVS tubes are generally selected in series, and the threshold voltage V _TH after series connection is 1.1 times the bus voltage. The bus voltage V _DC of the present invention is 600V, and three SMBJ220CA are selected to be connected in series.

Based on the above, the HCPL-316J driver chip used in the present invention has an overcurrent soft shutdown function, and has optocoupler isolation between its internal input and output, which improves system stability and safety while reducing the number of components in the driver circuit; At the same time, an active clamp protection circuit is added between the collector and gate of the IGBT, between the collector of the IGBT and the HCPL-316J drive output Vout (base stage of the push-pull circuit), to ensure that the IGBT is turned off at the moment, The spike voltage generated by the stray inductance in the inverter circuit will not damage the IGBT.

It can be known from common technical knowledge that the present invention can be realized through other embodiments without departing from its spirit or essential features. Accordingly, the above-disclosed embodiments are, in all respects, illustrative and not exclusive. All changes within the scope of the present invention or within the scope equivalent to the present invention are embraced by the present invention.

Claims (6)

1. An active clamp protection circuit driven by an IGBT based on HCPL-316J, characterized in that it comprises a control module, HCPL-316J driver chip, IGBT overcurrent protection circuit and active clamp protection circuit; The control module includes a DSP unit, the PWM output pin of the DSP unit is connected to the PWM output terminal, the PWM wave is output, the reset signal and the FAULT signal are connected to the IO port of the DSP unit, and the reset signal and the fault signal are provided for the HCPL-316J chip respectively. For the return interface, a resistor is connected to the PWM output pin of the DSP unit to prevent the IGBT overcurrent protection circuit from being misconducted during the DSP initialization process, and a diode is connected in series to the FAULT signal connection line; The HCPL-316J driver chip is combined with the DSP to realize the driving of the IGBT overcurrent protection circuit. The input side power supply of the HCPL-316J driver chip is shared with the DSP unit, and its output side is connected to the DC/DC module power supply. The output voltage is +15V and -8V, and connect several bypass capacitors between the +15V power supply terminal, -8V power supply terminal and ground; The IGBT overcurrent protection circuit is connected to the DESAT end of the HCPL-316J driver chip, and two FR107 fast recovery diodes and two 1N4148 diodes are connected to the DESAT end as clamping diodes to protect the HCPL-316J chip; The active clamping protection circuit is connected to the Vout end of the HCPL-316J driver chip, and the active clamping protection circuit is connected in parallel with an 18V bidirectional TVS tube between the gate and the emitter, through the TVS tube and two ES1D fast recovery rectifier diodes Connect the gate and collector of the IGBT, and connect the collector of the IGBT to the base of the push-pull circuit. 2. A kind of active clamp protection circuit driven by an IGBT based on HCPL-316J according to claim 1, characterized in that: said HCPL-316J drive chip contains an optocoupler isolation circuit and a push-pull drive circuit, DSP After the PWM signal is output to the HCPL-316J driver chip, the PWM signal passes through the optocoupler isolation circuit, and then the power is amplified by the push-pull drive circuit to drive the IGBT overcurrent protection circuit. 3. A kind of active clamping protection circuit driven by an IGBT based on HCPL-316J according to claim 1, characterized in that: when the IGBT overcurrent protection circuit is driven, the DSP unit only needs one IO port as a fault return transfer interface. 4. An active clamping protection circuit driven by an IGBT based on HCPL-316J according to claim 1, characterized in that: two FR107 fast recovery diodes are connected in series, and two 1N4148 diodes are connected in parallel. 5. A kind of active clamp protection circuit driven by IGBT based on HCPL-316J according to claim 1, characterized in that: 5 bypass pins are connected between the +15V power terminal of the DC/DC module power supply and the ground The 5 bypass capacitors are connected in parallel with each other, and 5 bypass capacitors are also connected between the -8V power supply terminal of the DC/DC module power supply and the ground, and the 5 bypass capacitors are also connected in parallel with each other. 6. An active clamping protection circuit driven by an IGBT based on HCPL-316J according to claim 1, characterized in that: the threshold voltage of the TVS tube is higher than its DC bus voltage and lower than the IGBT overcurrent Safe voltage to protect the circuit.