JP2014117112A - Semiconductor control device, and power conversion equipment - Google Patents

Abstract

Immediately after detecting a short circuit, the gate resistance at the time of turn-on is switched, the turn-on is delayed to suppress di / dt, and short circuit vibration is prevented.
In order to perform orthogonal transformation, a main circuit is constituted by a plurality of switching elements, and the first switching element, the first resistor, the second resistor, and the second switching element are arranged in this order between the DC power supply terminals. A first series circuit in which a connection point of the first resistor and the second resistor is connected to a gate of the switching element, a third switching element and a third resistor are arranged in this order, and a DC power supply terminal And a second series circuit connected between one end of the switching element and the gate of the switching element. The first switching element and the second switching element are alternately controlled by a control signal, and a short circuit of the main circuit is detected. Then, the third switching element is turned on to connect the third resistor having a resistance value larger than that of the first resistor to the gate of the switching element.
[Selection] Figure 1

Description

  The present invention relates to a semiconductor control device and a power conversion device, and more particularly to a semiconductor control device and a power conversion device capable of reducing di / dt of a short-circuit current at the time of a short circuit while ensuring high speed.

  The power converter is a function for converting DC power supplied from a DC power source into AC power for supplying an AC electric load such as a rotating electrical machine, or for supplying AC power generated by the rotating electrical machine to a DC power source. It has a function to convert to DC power. In order to perform this conversion function, the power conversion device has an inverter circuit having a plurality of switching elements, and the switching elements repeat the conduction operation and the interruption operation to change from DC power to AC power or from AC power to DC power. Power conversion.

  In a circuit for driving a switching element, there is a problem that if there is no protection circuit in the event of an abnormality such as a power supply short circuit, an excessive current flows through the switching element and the element is destroyed due to heat generation or switching surge voltage.

  A technique for suppressing this short-circuit overcurrent is described in Patent Document 1 (Japanese Patent Laid-Open No. 3-40517). Patent Document 1 describes that, for example, a sense IGBT is used as a switching element, an overcurrent and a short circuit are detected based on the sense current, and the switching element IGBT is cut off.

Japanese Patent Laid-Open No. 3-40517

  Japanese Patent Application Laid-Open No. 2004-228561 discloses a countermeasure for shutting off the switching element IGBT at the time of an overcurrent and a short circuit. However, a countermeasure should be taken on the turn-on side as described below.

  In power converters, it is desirable to reduce power loss during operation as much as possible. As part of measures to reduce this loss, the gate resistance when switching elements are turned on is lowered to speed up switching.

  This measure is effective for reducing the loss during normal operation, but because the gate resistance is small, the di / dt of the short-circuit current rapidly increases at the time of a short circuit, causing the short-circuit current to oscillate and possibly causing the switching element IGBT to break down. Occurs. For this reason, at the time of a short circuit, it is desirable to reduce di / dt as a countermeasure on the turn-on side.

  Accordingly, an object of the present invention is to provide a semiconductor control device and a power conversion device that can switch a gate resistance at the time of turn-on immediately after detecting a short-circuit, delay a turn-on to suppress di / dt, and prevent a short-circuit vibration. .

  From the above, in the present invention, a semiconductor control device that constitutes a main circuit with a plurality of switching elements in order to perform conversion between direct current and alternating current, and the control device that determines the gate signal of the switching elements includes: One switching element, a first resistor, a second resistor, and a second switching element are arranged between the DC power supply terminals in this order, and a connection point of the first resistor and the second resistor is connected to the gate of the switching element. A first series circuit, a third switching element and a third resistor arranged in this order, and a second series circuit connected between one end of the DC power supply terminal and the gate of the switching element, The first switching element and the second switching element are alternately controlled by a control signal from the host control device, and a short circuit of the main circuit is detected and the third switching element is turned on. Than the first resistor are turned on, characterized in that for connecting the third resistor having a large resistance value to the gate of the switching element.

  ADVANTAGE OF THE INVENTION According to this invention, the current vibration and surge voltage which generate | occur | produce at the time of a short circuit can be reduced, and high-speed switching, a low loss, high noise resistance, and a highly reliable small power module can be provided.

  Moreover, according to the Example of this invention, the small and high output power converter device provided with the said power module circuit between a drive part and a vehicle-mounted rotary electric machine can be provided.

The figure which shows the typical structure of a semiconductor control apparatus. The block diagram which shows a specific electrical circuit structure. The figure which shows the structure of another semiconductor control apparatus. The block diagram which shows another concrete electrical circuit structure. The figure which shows each part waveform at the time of the normal time by a conventional system, and a short circuit. The figure which shows each part waveform at the time of the normal time by this invention system, and a short circuit. The figure which shows the electrical circuit structure of an inverter apparatus.

  Embodiments of the present invention will be described below with reference to the drawings.

  In the embodiments described below, a power conversion device using the power module of the present invention will be described as an example.

  The configuration described below can also be applied to a DC-DC power converter such as a DC / DC converter or a DC chopper. Moreover, the structure demonstrated below is applicable also to power converters, such as vehicle-mounted use, industrial use, and household use.

  A first embodiment of the present invention will be described with reference to the drawings. First, the electrical circuit configuration of the inverter device INV of this embodiment will be described with reference to FIG.

  The inverter device INV of the present embodiment includes a power module PMU, a drive circuit device DCU, and an electric motor control unit MCU.

  The power module PMU constitutes a main circuit for power conversion, operates in response to the control signals VP and VN output from the drive circuit unit DCU, and converts the DC power supplied from the high voltage battery BAT into three-phase AC power. Converted and supplied to the stator winding of the motor M.

  The main circuit is a three-phase bridge circuit, and a series circuit A (AU, AV, AW) for three phases is electrically connected in parallel between the positive electrode P side and the negative electrode N side of the high voltage battery BAT. ing. The series circuit A (AU, AV, AW) is also called an arm, and is composed of two power semiconductor elements MP, MN.

  The arm A (AU, AV, AW) is configured by electrically connecting an upper arm power semiconductor element MP and a lower arm power semiconductor element MN in series. In this embodiment, IGBTs (insulated gate bipolar transistors) are used as the power semiconductor elements MP and MN. In the IGBT, it is necessary to separately connect a diode element between the collector electrode and the emitter electrode. The IGBT includes a gate electrode in addition to the collector electrode and the emitter electrode. Control signals VP and VN output from the drive circuit unit DCU are applied to the gate electrode.

  As the power semiconductor elements MP and MN, n-channel MOSFETs (metal oxide semiconductor field effect transistors) which are switching semiconductor elements may be used. A semiconductor chip constituting the MOSFET includes three electrodes, a drain electrode, a source electrode, and a gate electrode. In addition, a parasitic diode having a forward direction from the source electrode to the drain electrode is electrically connected between the drain electrode and the source electrode.

  The U-phase arm Au is configured by electrically connecting an emitter electrode of the power semiconductor element Mpu and a collector electrode of the power semiconductor element Mnu in series. The V-phase arm Av and the W-phase arm Aw are the same as the U-phase arm Au, and are configured such that the emitter electrodes of the power semiconductor elements Mpv and Mpw and the collector electrodes of the power semiconductor elements Mnv and Mnw are electrically connected in series. Yes.

  Although details are omitted, u, v, and w given to the arm A and the power semiconductor element M mean AC phases of the stator winding of the motor M, and P and N are positive poles of the high-voltage battery BAT, Means negative electrode. This convention also applies to the following explanation of symbols.

  The collector electrodes of the semiconductor elements Mpu, Mpv, and Mpw are electrically connected to the high potential side (positive electrode side) of the high-voltage battery BAT. The emitter electrodes of the power semiconductor elements Mnu, Mnv and Mnw are electrically connected to the low potential side (negative electrode side) of the high voltage battery BAT. The midpoint of the U-phase arm Au (the connection portion between the emitter electrode of the upper arm side power semiconductor element and the collector electrode of the lower arm side power semiconductor element) is electrically connected to the U phase stator winding of the motor M. Yes. Similarly to the midpoint of the u-phase arm Au, the midpoint of the V-phase arm Av and the W-phase arm Aw is electrically connected to the V-phase and W-phase stator windings of the motor M.

  A smoothing electrolytic capacitor SEC is electrically connected between the positive electrode side and the negative electrode side of the high-voltage battery BAT in order to suppress fluctuations in DC voltage caused by the operation of the power semiconductor element.

  In the power module PMU, a semiconductor chip is mounted on a base surrounded by a case via an insulating substrate so that a three-phase bridge circuit is formed. Between the semiconductor chips, between the semiconductor chip and the input terminal, the semiconductor chip And the output terminal are electrically connected by a connection conductor such as an aluminum wire or a plate-like conductor. The base is made of a heat conductive member such as copper or aluminum. The lower surface of the base is cooled by a cooling medium such as air or cooling water. Fins and the like are provided on the lower surface of the base in order to improve the cooling efficiency by the cooling medium. The insulating substrate is made of an insulating member such as aluminum nitride, and wiring patterns are metallized on both sides. The semiconductor chip constitutes the IGBT described above, and has electrodes on both sides. The base and the insulating substrate, and the insulating substrate and the semiconductor chip are joined by a joining member such as solder.

  The drive circuit unit DCU is electrically connected to the gate electrodes of the power semiconductor elements Mpu, Mpv, Mpw, Mnu, Mnv, and Mnw.

  The drive circuit unit DCU receives the control signals Vpu *, Vpv *, Vpw * of the upper arm power semiconductor elements Mpu, Mpv, Mpw output from the motor control unit MCU, and receives the received control signals Vpu *, Vpv *, Vpw. * Is output to the gate electrodes of the upper arm power semiconductor elements Mpu, Mpv, Mpw as control signals Vpu, Vpv, Vpw for driving the upper arm power semiconductor elements Mpu, Mpv, Mpw.

  The drive circuit unit DCU receives the control signals Vnu *, Vnv *, Vnw * of the lower arm power semiconductor elements Mnu, Mnv, Mnw output from the motor control unit MCU, and receives the received control signals Vnu *, Vnv *, Vnw * is output to the gate electrodes of the lower arm power semiconductor elements Mnu, Mnv, Mnw as control signals Vnu, Vnv, Vnw for driving the lower arm power semiconductor elements Mnu, Mnv, Mnw.

  The motor control unit MCU calculates a control value for operating the power semiconductor element of the power module PMU based on a plurality of input signals that are input, and calculates the calculated control values as control signals Vpu *, Vpv *, Vpw. *, Vnu *, Vnv *, and Vnw * are output to the drive circuit unit DCU, and are provided with a microcomputer (hereinafter referred to as “microcomputer”) that calculates control values.

  The microcomputer has as input signals a torque command signal (torque command value) τ *, a rotation speed command signal (rotation speed command value) n *, detection signals (current values of u phase to w phase) iu, iv, iw, and A detection signal (rotor magnetic pole position) θ is input.

  The torque command signal (torque command value) τ * and the rotation speed command signal (rotation speed command value) n * are output from a higher-level integrated control device (not shown) according to the vehicle operation mode. Detection signals (u-phase, v-phase, and w-phase current values) iu, iv, and iw are output from current sensors Cu, Cv, and Cw. The detection signal (rotor magnetic pole position) θ is output from a magnetic pole position sensor (not shown).

  Current sensors Cu, Cv, and Cw detect u-phase, v-phase, and w-phase currents iu, iv, and iw supplied from the inverter device INV (power module PMU) to the stator winding of the stator of the motor M. It is comprised from a shunt resistor, a current transformer (CT), etc.

  The magnetic pole position sensor is for detecting the magnetic pole position θ of the rotor of the motor M, and includes a resolver, an encoder, a Hall element, a Hall IC, and the like.

  The microcomputer calculates the d-axis and q-axis current command values Id * and Iq * based on the input signal, and calculates the voltage control values Vu, Vv and Vw based on the calculated current command values Id * and Iq *. The calculated voltage control values Vu, Vv, and Vw are used as control signals (PWM signals (pulse width modulation signals)) Vpu *, Vpv *, Vpw *, and Vnu * for operating the power semiconductor elements of the power module PMU. , Vnv *, Vnw * are output to the drive circuit unit DCU.

  Next, the configuration of the semiconductor control device of this embodiment will be described in detail with reference to FIGS.

  FIG. 1 shows a typical configuration of a semiconductor control device of a switching element MNu constituting a lower arm (negative electrode side) of a U-phase arm Au in the power module PMU of the present embodiment. The other phases of the power module PMU or the upper arm can be handled by the same circuit configuration, and therefore illustration and description thereof are omitted here. In the following description, it is assumed that the switching element MNu is, for example, an IGBT and has a function of detecting a sense current. Further, MNu is expressed as a switching element 24.

  Here, a diode element 25 is electrically connected in parallel with a switching element (hereinafter simply referred to as IGBT) 24. Further, the IGBT 24 includes a current sensing IGBT 100 that detects the main current. For example, a sense current that is one thousandth of the main current flows. The sense resistor 101 converts a sense current into a sense voltage.

  DCUNu is a circuit portion (driver) that controls the switching element MNu constituting the lower arm (negative electrode side) of the U-phase arm Au in the drive circuit unit DCU. The driver DCUNu obtains the control signal Vnu * from the motor control unit MCU to the drive circuit 105 and gives the control signal Vnu to the IGBT 24. This circuit portion is well known in the art and will not be described in detail. In the present invention, the initial purpose is achieved by correcting the control signal Vnu provided to the IGBT 24 by the drive circuit 105 in accordance with the short circuit detection signal.

  In order to correct the control signal Vnu, a short circuit di / dt control unit 106 and a drive cutoff unit 104 are provided in the driver DCUNu. The short-circuit di / dt control unit 106 executes a process of reducing di / dt as a countermeasure on the turn-on side at the time of the short circuit, and the drive cutoff unit 104 blocks the switching element IGBT as a countermeasure on the cutoff side at the time of the short circuit. Note that a short-circuit detection unit 102 and a noise mask unit 103 are provided for pre-processing of the drive cutoff unit 104. Both the short-circuit di / dt control unit 106 and the drive cutoff unit 104 execute the subsequent processing with the sense voltage detected and converted by the sense resistor 101 as an input.

  First, the operation on the drive cutoff side described in Patent Document 1 will be described. Here, the sense voltage detected and converted by the sense resistor 101 is applied to the short-circuit detection unit 102, and when this exceeds a predetermined threshold, a short-circuit detection signal is output. This detection output enters the noise mask unit 103, and if the detection signal is due to switching noise of the IGBT 24, the detection signal is masked, otherwise the short-circuit detection signal is passed. Since the switching noise is a harmonic, the noise mask unit 103 removes the switching noise by an integration function. The drive cut-off unit 104 receives a short circuit detection signal from the noise mask unit 103 and sends a cut-off signal to the drive unit 105 that drives the IGBT 24.

  In addition, the drive interruption | blocking part 104 may be provided with the function which performs interruption | blocking operation besides the said interruption | blocking operation | movement at the time of a short circuit. These are logic functions for sending a shut-off signal to the drive unit 105 in response to the detection signal of these abnormal states when the gate power supply of the IGBT 24 falls below a predetermined voltage or when the IGBT 24 exceeds a predetermined temperature. It is good to also have.

  The drive unit 105 receives a control signal sent from the host motor control unit MCU and sends a control signal for turning on and off the IGBT 24. Note that the control signal from the upper level is usually electrically insulated by, for example, a photocoupler. The drive unit 105 also has a soft cutoff function that receives the cutoff signal from the drive cutoff unit 104 and slowly turns off the IGBT 24.

  In the present invention, a process for reducing di / dt is executed as a countermeasure on the gate-on side at the time of a short circuit. The short-circuit di / dt control unit 106 has a function of reducing the short-circuit current di / dt by slowly turning on the IGBT 24 when a sense voltage is received and a predetermined threshold value is exceeded.

  FIG. 2 is a block diagram showing a specific electrical circuit configuration of the present embodiment. In this circuit, the operation during normal operation will be described first, and then the operation during short circuit will be described.

  In FIG. 2, the driving unit 105 receives a control signal Vnu * sent from the host motor control unit MCU and sends a control signal for turning on and off the IGBT 24 to the gate of the IGBT 24. Note that the control signal Vnu * from the upper level is normally electrically insulated by, for example, a photocoupler.

  The drive unit 105 is connected to a control power supply Vcc and a ground for a normal circuit operation, in which a pMOS 211, a resistor Rg (on), a resistor Rg (off), and a pMOS 208 are connected in series in this order. Connected between.

  Among these, the pMOS 211 is a switching element that turns on the IGBT 24 in response to a control signal Vnu * from the host, and can output, for example, a current of several ampere class. In this figure, the drive unit 105 is composed of MOS transistors, but the same function is achieved with bipolar transistors. The on-gate resistance Rg (on) 210 is a resistor that limits a current that charges the gate input capacitance of the IGBT 24 when the IGBT 24 is turned on.

  As mentioned earlier, it is desirable for power converters to reduce power loss during operation as much as possible. As part of measures to reduce this loss, the gate resistance when switching elements are turned on is lowered to speed up switching. ing. The resistance value of the on-gate resistance Rg (on) 210 is set in accordance with the viewpoint for increasing the speed.

  The nMOS 208 is a switching element that receives the control signal Vnu * from the host and turns off the IGBT 24, and can output, for example, a current of several ampere class. In this figure, the drive unit is composed of MOS transistors, but the bipolar transistor has the same function. The off-gate resistance Rg (off) 209 is a resistor for extracting the charge accumulated in the gate input capacitance of the IGBT 24 when the IGBT 24 is turned off.

  In contrast to the circuit configuration of the driving unit 105 for the operation during the normal operation described above, the following circuit configuration is used for the operation of “cutting off the switching element by detecting an overcurrent and a short circuit based on the sense current” in Patent Document 1. Has been added. The circuit for this countermeasure is a short circuit detection unit 102, a noise mask unit 103, and a drive cutoff unit 104. Further, in order to receive the signal from the drive shut-off unit 104 and shut off the IGBT 24, between the connection point (gate terminal of the IGBT 24) of the resistor Rg (on) and the resistor Rg (off) in the drive unit 105 and the ground, A series circuit of a soft blocking gate resistance Rg (sc) 207 and an nMOS 206 is connected. The nMOS 206 is a switching element that operates when receiving a cutoff signal from the drive cutoff unit 104 and performing a soft cutoff.

  The circuit configuration and its operation will be described sequentially from the short-circuit detection unit 102 along the signal flow. First, the short-circuit detection unit 102 shown in FIG. 2 is configured with the comparator 201 as the center, inputs a sense voltage of the sense resistor 101, and outputs a short-circuit detection signal (for example, a High signal) when a predetermined threshold value Vic1 is exceeded. The threshold value Vic1 is a reference voltage determined based on the sense ratio and sense resistance of the sense IGBT 100, for example, a current several times the rated current of the IGBT 24. For example, the threshold value Vic1 is generated from a highly accurate reference power source such as a band gap reference by resistance voltage division. ing.

  The detection output of the short-circuit detection unit 102 enters the noise mask unit 103, and the detection signal is masked if the detection signal is due to, for example, switching noise of the IGBT 24 of several microseconds or less. If the detection signal exceeds several microseconds, the IGBT 24 is short-circuited. The state is determined and the short circuit detection signal is passed.

  The drive cutoff unit 104 receives the short circuit detection signal and sends a cutoff signal to the drive unit 105 that drives the IGBT 24. The drive shut-off unit 104 receives a detection signal of an abnormal state such as when the gate power supply of the IGBT 24 falls below a predetermined voltage, or when the IGBT 24 exceeds a predetermined temperature, and sends a cut-off signal to the drive unit 105 Also have.

  The drive unit 105 has a soft cutoff function that receives the cutoff signal from the drive cutoff unit 104 and slowly turns off the IGBT 24. In the drive unit 105, the nMOS 206 is a switching element that operates when receiving a cutoff signal from the drive cutoff unit 104 and performing a soft cutoff. The soft-blocking gate resistance Rg (sc) 207 is a resistor that slowly draws out the charge accumulated in the gate input capacitance of the IGBT 24 when the IGBT 24 is soft-turned off. For example, the number of the off-gate resistance Rg (off) 209 The resistance value is about ten to several hundred times.

  The above operations performed by the drive unit 105 in response to a signal from the drive cut-off unit 104 are operations on the current cut-off side. On the other hand, the present invention takes measures against the turn-on side. The short circuit di / dt control unit 106 is additionally installed for this purpose. As a countermeasure against this turn-on, a soft turn-on gate resistor Rg (di) 205 and a pMOS 205 are connected between the connection point (gate terminal of the IGBT 24) of the resistor Rg (on) and the resistor Rg (off) in the driving unit 105 and the ground. Are connected in series. In addition, a comparator 202 and an inverter 203 are provided to detect a short circuit.

  The short-circuit di / dt control unit 106 configured as described above has a function of reducing the short-circuit current di / dt by slowly turning on the IGBT 24 when the sense voltage is received and exceeds a predetermined threshold value. Specific circuit operations will be described below.

  First, the comparator 202 inputs the sense voltage of the sense resistor 101, and outputs a short circuit detection signal (for example, a High signal) when a predetermined threshold value Vic2 is exceeded. The threshold value Vic2 is a reference voltage determined based on the sense ratio and sense resistance of the sense IGBT 100, for example, a current several times the rated current of the IGBT 24, and is generated from a highly accurate reference power source such as a band gap reference, for example, by resistance voltage division. Yes. The threshold value Vic1 of the comparator 201 and the threshold value Vic2 of the comparator 202 are the same. The inverter 203 outputs a signal for inverting the polarity of the short circuit detection signal (for example, High signal) of the comparator 202.

  The pMOS 205 in the short-circuit di / dt control unit 106 is a switching element and is driven by the output of the inverter 203. For this reason, since the short circuit current flows and the comparator 202 is driven after detecting this, the pMOS 205 is turned on halfway until the short circuit current reaches the peak.

  On the other hand, the output of the comparator 202 is also given to the pMOS 211 of the drive circuit 105. As a result, the pMOS 205 is turned on and at the same time, the pMOS 211 is turned off to disconnect the on-gate resistance Rg (on) and switch to the soft-turn-on gate resistance Rg (di) 205. In this figure, the drive unit is composed of MOS transistors, but the bipolar transistor has the same function.

  The soft turn-on gate resistance Rg (di) 205 is a resistor that slowly charges the gate input capacitance of the IGBT 24 in order to reduce the di / dt of the short-circuit current in the middle of the short-circuit current of the IGBT 24 reaching a peak. The resistance value is about several tens to several hundred times as large as the on-gate resistance Rg (on) 210.

  In this embodiment, an IGBT is used for the power semiconductor element 24, but a MOSFET may be used. In the case of a MOSFET, no diode is required. Moreover, although the IGBT and the diode are connected one by one, the number thereof depends on the capacity of the power conversion device, and N may be connected in parallel. In the above description, the configuration of the U-phase arm Au has been described, but the V-phase arm Av and the W-phase arm Aw have the same configuration.

  Hereinafter, the current suppression effect of the gate-on part at the time of a short circuit achieved by the process of the present invention will be described with reference to the drawings in comparison with the conventional method. First, FIG. 5 shows waveforms at the normal time and short circuit in the conventional method. FIG. 5 shows time on the horizontal axis and the current, voltage waveforms, etc. of each part of the circuit in FIG. 2 on the vertical axis. In addition, each part waveform during normal operation is shown in the first half, and each part waveform during short circuit is shown in the second half. The conventional method assumes a circuit that does not include the short-circuit di / dt control unit 106 in FIG.

  The time-series waveforms shown in FIG. 5 are the gate voltage 75 of the pMOS 211, the gate voltage 76 of the nMOS 208, the gate voltage 77 of the nMOS 206, the gate voltage Vge71 of the IGBT 24 (MNu in FIG. 7), the gate current Ig72 of the IGBT 24, The collector-emitter voltage 74 of the positive side IGBT (MPu in FIG. 7) and the collector current 73 of the positive side IGBT are shown.

  The normal operation by this circuit is well known and will not be described in detail. However, in the pMOS 211 for turn-on, the gate voltage 75 periodically repeats the high level H and the low level L according to the control signal. Even in the nMOS 208 for turn-off, the gate voltage 76 periodically repeats the high level H and the low level L according to the control signal, but the gate voltage 75 rises after the gate voltage 76 falls, and the gate voltage 75 falls after the gate voltage 75 falls. The time relationship that 76 rises is maintained. As a result, the gate voltage Vge71 of the IGBT 24 (MNu in FIG. 7) can be stably turned on and off. The gate current Ig72 of the IGBT 24 is generated at the time of turn-on and turn-off operation transients.

  On the other hand, the positive-side IGBT (MPu in FIG. 7) connected in series with the IGBT 24 (MNu in FIG. 7) to form the U-phase arm is similarly turned on and off in normal operation. As a result, the collector-emitter voltage 74 of the positive-side IGBT (MPu in FIG. 7) shown in FIG. 5 and the collector current 73 of the positive-side IGBT appear.

  On the other hand, in the operation at the time of short circuit in the right half of FIG. 5, the waveform fluctuates as follows. First, in a short circuit state, the turn-off nMOS 208 lowers the gate voltage 76 by the control signal, and then the turn-on pMOS 211 sequentially raises the gate voltage 75 by the control signal. As a result, the gate voltage Vge71 of the IGBT 24 (MNu in FIG. 7) and the gate current Ig72 of the IGBT 24 increase. However, the magnitudes of the gate voltage Vge71 greatly exceed the normal value and are steep. Further, the gate current Ig72 becomes an oscillating current and starts to increase and decrease repeatedly. The gate current Ig72 initially increases, then decreases, and this is repeated thereafter.

  On the other hand, with regard to the positive-side IGBT (MPu in FIG. 7) in this state, when a short-circuit current (gate current Ig72) starts to flow at the time of a short circuit, the short circuit current di / dt and the parasitic of the wiring connecting the switching element and the battery An induced electromotive voltage is generated by the inductance L, and the collector-emitter voltage 74 decreases. When the short-circuit current (gate current Ig72) of the IGBT 24 reaches a peak and starts to decrease, the collector-emitter voltage 74 increases. Along with this, the collector current 73 of the positive-side IGBT also increases or decreases. Thereafter, the current / voltage oscillation as shown in this figure is repeated as the short-circuit current increases or decreases. Further, current flows to the gate due to the time variation dv / dt of the collector-emitter voltage and the feedback capacitance of the IGBT 24, and further induces collector voltage oscillation.

  The nMOS 206 of the drive unit 105 is driven via the short-circuit detection unit 102 and the drive cutoff unit 104, and the gate voltage 77 of the nMOS 206 is set to a high level to perform the cutoff operation of the IGBT 24. In the meantime, it has been damaged by current / voltage vibration. In particular, the damage in the initial state of the short circuit is large.

  On the other hand, in the waveform of the present invention shown in FIG. 6, current / voltage oscillation is suppressed. FIG. 6 also shows waveforms at normal time and short circuit, but the difference from FIG. 5 is that a gate voltage 78 of the pMOS 205 is newly added, and other waveforms are completely the same as FIG. The same thing is displayed. The pMOS 205 functions only when a short circuit is detected, and is maintained at a low level L during normal operation, and therefore exhibits the same operation waveform as that of FIG. For this reason, the following explanation is given only about the operation at the time of a short circuit.

  In the short-half operation in the right half of FIG. 6, the turn-off nMOS 208 lowers the gate voltage 76 by the control signal, and then the turn-on pMOS 211 sequentially raises the gate voltage 75 by the control signal. As a result, the gate voltage Vge71 of the IGBT 24 (MNu in FIG. 7) and the gate current Ig72 of the IGBT 24 increase.

  In the present invention, in parallel with the above operation, the comparator 202 detects that a short-circuit current has started to flow when a short circuit occurs, turns off the pMOS 211, and turns on the pMOS 205. That is, the pMOS 211 is lowered at the output of the comparator 202 immediately after the rise by the control signal. As a result, the resistor Rg (on) 210 having a small gate resistance value is connected to the gate terminal of the IGBT 24 only for a short time, but immediately switches to the resistor Rg (di) 204 having a large gate resistance value. As a result, the turn-on speed of the IGBT 24 becomes slow.

  According to the waveform 71 in FIG. 6 (gate voltage Vge of IGBT 24 (MNu in FIG. 7)), the voltage rapidly rises for a short period from the rise to the fall of the pMOS 211, but the slope of the voltage increase sharply decreases immediately after the pMOS 205 is turned on. I am letting. It can also be seen that the gate current Ig72 of the IGBT 24 has a suppressed current peak value and does not cause subsequent current oscillation.

  On the other hand, with regard to the positive side IGBT (MPu in FIG. 7) in this state, when the short circuit current (gate current Ig72) starts to flow at the time of the short circuit, the IGBT 24 starts to short circuit due to the short circuit di / dt control of the present invention, and reaches the peak current. By the time, the di / dt of the positive-side IGBT (MPu in FIG. 7) decreases, and the peak current value also decreases compared to the conventional case. For this reason, short circuit current oscillation is eliminated. In addition, since di / dt is reduced as compared with the prior art, the drop amount of the emitter-collector voltage 74 is also smaller than in the conventional case, and the dv / dt of the collector-emitter voltage 74 is also reduced, which is induced by the feedback capacitance of the IGBT 24. The gate current is also reduced and the collector voltage oscillation is eliminated. Although the U-phase arm Au has been described, the same applies to the V-phase arm Av and the W-phase arm Aw.

  As described above, according to this embodiment, it is possible to reduce current vibration and surge voltage generated at the time of a short circuit, and it is possible to provide a small power module with high speed switching, low loss, high noise resistance, and high reliability. Moreover, according to the present Example, the small and high output power converter device provided with the said power module circuit between a drive part and a vehicle-mounted rotary electric machine can be provided.

  Further, since the power module can be downsized, the cooling device of the inverter device INV can be downsized and reduced in cost.

  Note that modularization may be performed in units of each phase (2 in 1). Or you may carry out by the form (6 in 1) which put all together.

  Next, a second embodiment of the present invention will be described with reference to FIG. In the first embodiment, the threshold value Vic1 of the comparator 201 and the threshold value Vic2 of the comparator 202 are the same, but in the second embodiment, the threshold value Vce2 is larger than the threshold value Vce1.

  Since the noise mask unit 103 is not included in the short circuit di / dt control unit of the first embodiment, there is a concern that the short circuit di / dt control unit 106 may operate due to erroneous detection of a short circuit due to switching noise of the IGBT 24 or the like. Therefore, the threshold value Vic2 is set to be larger than the threshold value Vic1, and malfunction of the short-circuit di / dt control unit 106 due to switching noise is prevented. Otherwise, the operation is exactly the same as that of the first embodiment.

  As described above, according to this embodiment, it is possible to reduce current vibration and surge voltage generated at the time of a short circuit, and it is possible to provide a small power module with high speed switching, low loss, high noise resistance, and high reliability. Moreover, according to the present Example, the small and high output power converter device provided with the said power module circuit between a drive part and a vehicle-mounted rotary electric machine can be provided.

  Further, since the power module can be downsized, the cooling device of the inverter device INV can be downsized and reduced in cost.

  Note that modularization may be performed in units of each phase (2 in 1). Or you may carry out by the form (6 in 1) which put all together.

  A third embodiment of the present invention will be described with reference to FIGS. The difference from the first embodiment is the short circuit detection method. In the first embodiment, the short circuit is detected using the sense IGBT 100, but in this embodiment, the short circuit is detected using the collector voltage of the IGBT 24. Otherwise, the operation is the same as in the first embodiment. FIG. 3 shows the configuration of the semiconductor control device of the lower arm (negative electrode side) of the U phase (V phase, W phase) Au (Av, Aw) in the power module PMU of the present embodiment.

  In FIG. 3, a diode element 25 is electrically connected in parallel with the switching element IGBT 24. Further, the collector voltage VCE of the IGBT 24 is introduced into the short circuit detection unit 102, and when this exceeds a predetermined threshold, a short circuit detection signal is output. This detection output enters the noise mask unit 103, and if the detection signal is due to switching noise of the IGBT 24, the detection signal is masked, otherwise the short-circuit detection signal is passed.

  The drive cut-off unit 302 receives the short-circuit detection signal and the gate voltage of the IGBT 24 and sends a cut-off signal to the drive unit 105 that drives the IGBT 24. The reason for inputting the gate voltage of the IGBT 24 is to prevent erroneous detection of a short circuit. In addition, it also has a logic function of sending an interruption signal to the drive unit 105 in response to a detection signal of an abnormal state such as when the gate power supply of the IGBT 24 falls below a predetermined voltage or when the IGBT 24 exceeds a predetermined temperature.

  The drive unit 105 receives a control signal sent from the host motor control unit MCU and sends a control signal for turning on and off the IGBT 24. Note that the control signal from the upper level is usually electrically insulated by, for example, a photocoupler. The driving unit 105 also has a soft cutoff function that receives the cutoff signal from the drive cutoff 302 and slowly turns off the IGBT 24.

  The short-circuit di / dt control unit 301 has a function of reducing the short-circuit current di / dt by slowly turning on the IGBT 24 when the collector voltage VCE of the IGBT 24 is received and a predetermined threshold value is exceeded.

  FIG. 4 is a block diagram showing a specific electrical circuit configuration of the present embodiment.

  First, a circuit configuration for detecting a short circuit with the collector voltage VCE will be described with reference to FIG. The diode 401 detects the collector voltage VCE of the IGBT 24. The diode 401 is turned on when the IGBT 24 is turned on and the collector voltage VCE falls below the control voltage Vcc. Output to control 301. The resistor 402 is connected to the control voltage Vcc and the diode 401, and limits the current value when the diode 401 becomes conductive.

  The comparator 201 receives an addition value of the collector voltage VCE when the IGBT 24 is turned on and the forward voltage of the diode 401, and outputs a short circuit detection signal (for example, a High signal) when a predetermined threshold value Vic1 is exceeded. The threshold value Vic1 is a reference voltage determined based on the collector-emitter voltage of the IGBT 24 when a current several times the rated current of the IGBT 24 flows, for example, and is generated from a high-accuracy reference power source such as a band gap reference by resistance voltage division. It has been.

  This detection output enters the noise mask unit 103, and if the detection signal is caused by switching noise of the IGBT 24 of, for example, several microseconds or less, the detection signal is masked. Pass the short circuit detection signal.

  The drive cut-off unit 302 receives the short-circuit detection signal and the gate voltage of the IGBT 24 and sends a cut-off signal to the drive unit 105 that drives the IGBT 24. The drive shut-off unit 302 receives a detection signal of an abnormal state such as when the gate power supply of the IGBT 24 falls below a predetermined voltage or when the IGBT 24 exceeds a predetermined temperature, and sends a cut-off signal to the drive unit 105 Also have.

  The drive unit 105 receives a control signal sent from the host motor control unit MCU and sends a control signal for turning on and off the IGBT 24. Note that the control signal from the upper level is usually electrically insulated by, for example, a photocoupler. The pMOS 211 is a switching element that turns on the IGBT 24 in response to a control signal from the host, and can output a current of several ampere class, for example. In this figure, the drive unit is composed of MOS transistors, but the bipolar transistor has the same function. The on-gate resistance Rg (on) 210 is a resistor that limits a current for charging the gate input capacitance of the IGBT 24 when the IGBT 24 is turned on.

  The nMOS 208 is a switching element that turns off the IGBT 24 in response to a control signal from the host, and can output a current of several ampere class, for example. In this figure, the drive unit is composed of MOS transistors, but the bipolar transistor has the same function. The off-gate resistance Rg (off) 209 is a resistor for extracting the charge accumulated in the gate input capacitance of the IGBT 24 when the IGBT 24 is turned off. The driving unit 105 also has a soft cutoff function that receives the cutoff signal from the drive cutoff 302 and slowly turns off the IGBT 24.

  The nMOS 206 is a switching element that operates when receiving a cutoff signal from the drive cutoff unit 104 and performing a soft cutoff. The soft-blocking gate resistance Rg (sc) 207 is a resistor that slowly draws out the charge accumulated in the gate input capacitance of the IGBT 24 when the IGBT 24 is soft-turned off. For example, from the tens of the off-gate resistance Rg (off) 209 The resistance value is about several hundred times.

  The short-circuit di / dt control unit 106 receives the added value of the collector voltage VCE at the turn-on time of the IGBT 24 and the forward voltage of the diode 401, and when this exceeds a predetermined threshold, the IGBT 24 is turned on slowly and the short-circuit current di / It has a function to lower dt.

  The comparator 202 receives an added value of the collector voltage VCE when the IGBT 24 is turned on and the forward voltage of the diode 401, and outputs a short circuit detection signal (for example, a high signal) when a predetermined threshold value Vic2 is exceeded. The threshold value Vic2 is a reference voltage that is determined based on the collector-emitter voltage of the IGBT 24 when a current several times the rated current of the IGBT 24 flows, for example, and is generated from a high-accuracy reference power source such as a band gap reference by resistance voltage division. It has been. The threshold value Vic1 of the comparator 201 and the threshold value Vic2 of the comparator 202 are the same.

  The logic unit 403 has a function of inputting a short circuit detection signal (for example, a high signal) of the comparator 202 and the gate voltage of the IGBT 24 to determine whether or not a short circuit has occurred. The reason why the gate voltage of the IGBT 24 is also input is to prevent erroneous detection of a short circuit. When the collector voltage VCE of the IGBT 24 exceeds the threshold value Vic2 of the comparator 202 and the gate voltage of the IGBT 24 is turned on, it is determined as a short circuit. To do.

  The pMOS 205 is a switching element, and the pMOS 205 is turned on in the middle of a short circuit current flowing until the current reaches a peak. At the same time as the pMOS 205 is turned on, the pMOS 211 is turned off to disconnect the on-gate resistance Rg (on) and switch to the soft-turn-on gate resistance Rg (di) 205. In this figure, the drive unit is composed of MOS transistors, but the bipolar transistor has the same function.

  The soft turn-on gate resistance Rg (di) 205 is a resistor that slowly charges the gate input capacitance of the IGBT 24 in order to reduce the di / dt of the short-circuit current in the middle of the short-circuit current of the IGBT 24 reaching a peak. The resistance value is about several tens to several hundred times as large as the on-gate resistance Rg (on) 210.

  In this embodiment, an IGBT is used as the power semiconductor element, but a MOSFET may be used. In the case of a MOSFET, no diode is required. Moreover, although the IGBT and the diode are connected one by one, the number thereof depends on the capacity of the power conversion device, and N may be connected in parallel. In addition, although the configuration of the U-phase arm Au has been described in the drawing, the V-phase arm Av and the W-phase arm Aw have the same configuration.

  The short-circuit waveform according to the present embodiment is the same as that of FIG. 6, and according to the present embodiment, it is possible to reduce current vibration and surge voltage generated at the time of short-circuit, and to achieve high-speed switching, low loss, high noise resistance, and a highly reliable small power module. Can provide. Moreover, according to the present Example, the small and high output power converter device provided with the said power module circuit between a drive part and a vehicle-mounted rotary electric machine can be provided.

100: IGBT for current sensing
101: Sense resistor 102: Short circuit detection unit 103: Noise mask unit 104: Drive cutoff unit 105: Drive unit 106: Short circuit di / dt control unit Mpu, Mpv, Mpw: Positive side IGBT
Mnu, Mnv, Mnw: Negative side IGBT
P: Positive side input terminal N: Negative side input terminal U, V, W: Output terminal

Claims (12)

A semiconductor control device that constitutes a main circuit by a plurality of switching elements to perform conversion between direct current and alternating current,
The control device for determining the gate signal of the switching element is:
The first switching element, the first resistor, the second resistor, and the second switching element are arranged in this order between the DC power supply terminals, and the connection point of the first resistor and the second resistor is the gate of the switching element. A first series circuit connected to
A third switching element and a third resistor arranged in this order, and a second series circuit connected between one end of the DC power supply terminal and the gate of the switching element;
The first switching element and the second switching element are alternately controlled by a control signal from a host controller, and a short circuit of the main circuit is detected to turn on the third switching element to thereby turn on the first resistor. A semiconductor control device, wherein the third resistor having a larger resistance value is connected to the gate of the switching element. The semiconductor control device according to claim 1,
The third switching element is turned on to connect the third resistance having a resistance value larger than that of the first resistance to the gate of the switching element, and to turn off the first switching element. Semiconductor control device. The semiconductor control device according to claim 1 or 2,
The switching device includes a sense current detection unit, and detects a short circuit of the main circuit from the detected sense current value. The semiconductor control device according to claim 1 or 2,
A semiconductor control device that detects a short circuit based on a collector voltage of the switching element. The semiconductor control device according to any one of claims 1 to 4, wherein:
A fourth resistor and a fourth switching element arranged in this order, and a third series circuit connected between the gate of the switching element and the other end of the DC power supply terminal,
Detecting a short circuit of the main circuit and turning on the fourth switching element to connect the fourth resistor having a resistance value larger than that of the second resistor to a gate of the switching element; Control device. A semiconductor control device that constitutes a main circuit by a plurality of switching elements to perform conversion between direct current and alternating current,
A drive unit for controlling the control voltage of the switching element; a current sensing switching element for sensing the current of the switching element; and a sense resistor for converting the current of the current sensing switching element into a sense voltage; A short-circuit detection unit that detects a short circuit based on the sense voltage, a noise mask unit that delays or filters a short-circuit detection signal output from the short-circuit detection unit, and a switching element that blocks the switching element based on a signal output from the filter unit And a short-circuit di / dt control unit that detects a short circuit based on the sense voltage and reduces a short-circuit current di / dt. The semiconductor element control device according to claim 6,
A semiconductor control device, wherein a detection threshold value of the short circuit di / dt control unit is larger than a detection threshold value of the short circuit detection unit. A semiconductor control device that constitutes a main circuit by a plurality of switching elements to perform conversion between direct current and alternating current,
A drive unit for controlling a control voltage of the switching element, a short-circuit detection unit that detects a short circuit based on a collector voltage of the switching element, and a noise mask that delays or filters a short-circuit detection signal output by the short-circuit detection unit A drive cutoff unit that shuts off the switching element based on a signal output from the filter unit and a gate voltage of the switching element, and a short circuit based on a collector voltage of the previous switching element and a gate voltage of the switching element. A semiconductor control device comprising: a short-circuit di / dt control unit that detects and reduces di / dt of a short-circuit current. A power converter electrically connected between a power source and a load,
A power module having a plurality of switching power semiconductor chips, a capacitor having a DC terminal, a drive circuit for controlling the switching power semiconductor chip, a DC terminal to which DC power is supplied, and a rotating electric machine An AC terminal for supplying a phase-cold flow,
A drive unit for controlling the control voltage of the switching element; a current sensing switching element for sensing the current of the switching element; and a sense resistor for converting the current of the current sensing switching element into a sense voltage; A short-circuit detection unit that detects a short circuit based on the sense voltage, a noise mask unit that delays or filters a short-circuit detection signal output from the short-circuit detection unit, and a switching element that blocks the switching element based on a signal output from the filter unit And a short-circuit di / dt control unit that detects a short circuit based on the sense voltage and reduces a short-circuit current di / dt. The power conversion device according to claim 9, wherein
The power conversion device, wherein a detection threshold value of the short-circuit di / dt control unit is larger than a detection threshold value of the short-circuit detection unit. A power converter electrically connected between a power source and a load,
A power module having a plurality of switching power semiconductor chips, a capacitor having a DC terminal, a drive circuit for controlling the switching power semiconductor chip, a DC terminal to which DC power is supplied, and a rotating electric machine An AC terminal for supplying a phase-cold flow,
A drive unit for controlling a control voltage of the switching element, a short-circuit detection unit that detects a short circuit based on a collector voltage of the switching element, and a noise mask that delays or filters a short-circuit detection signal output by the short-circuit detection unit A drive cutoff unit that shuts off the switching element based on a signal output from the filter unit and a gate voltage of the switching element, and a short circuit based on a collector voltage of the previous switching element and a gate voltage of the switching element. A power conversion apparatus comprising: a short-circuit di / dt control unit that detects and reduces di / dt of a short-circuit current. A semiconductor control device that constitutes a main circuit by a plurality of switching elements to perform conversion between direct current and alternating current,
A drive unit for controlling a control voltage of the switching element, a short-circuit detection unit for detecting a short circuit of the main circuit, and a drive cutoff unit for blocking the switching element based on a short-circuit detection signal output by the short-circuit detection unit And a short-circuit di / dt control section for reducing the short-circuit current di / dt based on the short-circuit detection signal.

Images