JP2018143050A - Intelligent power module and dead time setting device - Google Patents

Abstract

An intelligent power module and a dead time setting device capable of setting an optimum dead time according to variations of each element. A memory 11 stores an actual measured value of an on delay time and an off delay time of a pair of power switching elements Q1, Q2 measured by an on / off time measuring device 4, and an on-state of each power switching element stored in the memory. An adder 12 that calculates a dead time value at which both of the pair of power switching elements are turned off based on the measured values of the delay time and the off delay time; a dead time generation circuit 13 that generates a dead time based on the calculated dead time value; A PWM generation circuit 14 that generates a control signal for alternately turning on and off the pair of power switching elements based on the generated dead time, and drivers 3a and 3b that drive the pair of power switching elements by the generated control signal are provided. [Selection] Figure 1

Description

  The present invention relates to an intelligent power module and a dead time setting device for generating dead times of a high-side power switch element and a low-side power switch element.

  An intelligent power module (IPM) including a power device and a driver IC is composed of a high-side power switching element of an upper arm and a low-side power switching element of a lower arm made of MOSFET and IGBT (insulated gate bipolar transistor). Yes. Although the high-side power switching element and the low-side power switching element are alternately turned on, it is necessary to provide a dead time Td during which the upper and lower arms are turned off so that the upper and lower arms are not short-circuited.

  The dead time Td is equal to or greater than the difference obtained by subtracting the on-delay time (td (on) L) of the low-side power switching element from the off-delay time (toffH) of the high-side power switching element. The dead time Td is set so as to satisfy at least the difference obtained by subtracting the on-delay time (td (on) H) of the high-side power switching element from the off-delay time (toffL) of the low-side power switching element. There is a need to.

  The on-delay time td (on) and the off-delay time toff must take into account variations in the signal transmission time of the drive IC for driving the power switching element, the gate resistance, and the characteristics of the power switching element.

  For this reason, the dead time Td is set in consideration of the worst condition of variation of each power switching element so as to satisfy the conditions (a) and (b).

  As a conventional technique, a power semiconductor module shown in FIG. 7 described in Patent Document 1 is known. In the power semiconductor module, the current detection circuit 112 detects the current flowing through the low-side power switching element 123, the OFF signal OFF is input to the AND circuit 102, the current zero detection circuit 108 detects the zero current, and the zero detection signal is detected. Is input to the AND circuit 102, the on-operation of the high-side power switching element 121 is permitted through the level shift circuit 109.

JP 2002-204581 A

  However, when the dead time Td is set in consideration of the worst condition of variation of each power switching element so as to satisfy the conditions (a) and (b), a value larger than the dead time Td required for each product is set. Will be set. For this reason, motor current distortion increases, motor rotation ripple increases, and noise increases.

  Further, in the power semiconductor module shown in FIG. 7 described in Patent Document 1, since two sets of the zero current detection circuit 108 and the level shift circuit 109 are necessary, the circuit scale increases and the power consumption also increases. .

  An object of the present invention is to provide an intelligent power module and a dead time setting device capable of setting an optimum dead time according to the variation of each element.

  The intelligent power module according to the present invention includes a pair of power switching elements respectively provided on the upper and lower arms, and an on delay time of each power switching element of the pair of power switching elements measured by an external on / off time measuring device. A memory for storing an actual measured value of the off-delay time, and a dead time during which the pair of power switching elements are both turned off based on the actual measured values of the on-delay time and off-delay time of each of the power switching elements stored in the memory A calculation unit for calculating a value, a dead time generation circuit for generating a dead time based on the dead time value calculated by the calculation unit, and the pair of power switching elements based on the dead time generated by the dead time generation circuit Generate a control signal to turn on and off alternately A control circuit, characterized in that it comprises a drive circuit for driving the pair of power switching elements by a control signal generated by the control circuit.

  The dead time setting device of the present invention includes an intelligent power module, and an on / off time measuring device for measuring an on delay time and an off delay time of each of the power switching elements of the pair of power switching elements, and the intelligent power module includes: A memory for storing an actual measurement value of an on delay time and an off delay time of each of the pair of power switching elements measured by the on / off time measuring device; A calculation unit that calculates a dead time value at which both of the pair of power switching elements are turned off based on the actually measured values of the ON delay time and the OFF delay time of each of the power switching elements, and the dead calculated by the calculation unit Generate dead time based on time value A dead time generation circuit, a control circuit for generating a control signal for alternately turning on and off the pair of power switching elements based on the dead time generated by the dead time generation circuit, and a control signal generated by the control circuit And a drive circuit for driving the pair of power switching elements.

  According to the present invention, at the time of product inspection, the on-delay time and the off-delay time of the power switching element of each product are measured by the on-off time measuring device, and the dead time value for each product is stored in the intelligent power module. Write to memory. In other words, since the dead time value according to each product is used, the optimum dead time can be set according to the variation of each element. Therefore, a short circuit of the upper and lower arms can be prevented.

It is a figure which shows the circuit structure of the dead time setting apparatus provided with the intelligent power module which concerns on Example 1 of this invention. It is a figure which shows the process flowchart of the production factory of the intelligent power module which concerns on Example 1 of this invention. It is a figure which shows the definition of the on-delay time and off-delay time of a pair of power switching element Q1, Q2 of the dead time setting apparatus which concerns on Example 1 of this invention. It is a figure which shows writing to the memory of the ON delay time of the dead time setting apparatus concerning Example 1 of this invention, and an OFF delay time measurement result. It is a figure which shows reset of the dead time by the dead time setting apparatus which concerns on Example 1 of this invention. It is a figure which shows the circuit structure of the dead time setting apparatus provided with the intelligent power module which concerns on Example 2 of this invention. It is a figure which shows an example of the conventional semiconductor module for electric power.

  Hereinafter, a dead time setting device including an intelligent power module according to an embodiment of the present invention will be described in detail with reference to the drawings.

  The present invention measures the time td (on) H, td (on) L, toffH, and toffL in the product electrical characteristics shipment inspection process after assembling the intelligent power module in an intelligent power module having a dead time generation circuit. Then, by using the result, the optimum dead time value for each product is written in the memory, and the optimum dead time corresponding to the variation of each element is set.

Example 1
FIG. 1 is a diagram illustrating a circuit configuration of a dead time setting device including an intelligent power module according to a first embodiment of the present invention. The dead time setting device is a circuit for generating a dead time of a power switching element, and includes an intelligent power module (IPM) 1 and an on / off time measuring device 4 connected to the intelligent power module 1.

  The intelligent power module 1 includes a controller 2, a low side driver 3a, a high side driver 3b, and a pair of power switching elements Q1 and Q2 as switching devices. The pair of power switching elements Q1, Q2 is made of a MOSFET. The power switching elements Q1, Q2 may be IGBTs instead of MOSFETs.

  The pair of power switching elements Q1, Q2 are connected in series, and the drain of the power switching element Q2 of the upper arm is connected to the power supply terminal VBB. The source of the lower arm power switching element Q1 is connected to the ground terminal LS.

  The on / off time measuring device 4 is connected to the drain of the power switching element Q1 and the source of the power switching element Q2, and measures the on delay time and the off delay time of each power switching element of the pair of power switching elements Q1 and Q2. The measured on delay time and off delay time are output to the memory 11 in the controller 2. Details of a method for measuring the on-delay time and the off-delay time of each power switching element Q1, Q2 will be described later.

  The controller 2 includes a memory 11, an adder 12, a dead time generation circuit 13, and a PWM generation circuit 14. The memory 11 stores the actual measured values of the on delay time and the off delay time of each of the pair of power switching elements Q1 and Q2 measured by the on / off time measuring device 4.

  The adder 12 corresponds to the calculation unit of the present invention, and the pair of power switching elements Q1 and Q2 is based on the actually measured values of the on delay time and the off delay time of each power switching element Q1 and Q2 stored in the memory 11. The dead time value that turns off both is calculated.

  The dead time generation circuit 13 generates a dead time based on the dead time value calculated by the adder 12. The PWM generation circuit 14 corresponds to the control circuit of the present invention, and PWM (pulse width modulation) control for alternately turning on and off the pair of power switching elements Q1 and Q2 based on the dead time generated by the dead time generation circuit 13 Generate a signal.

  The low side driver 3a and the high side driver 3b correspond to the drive circuit of the present invention, and the low side driver 3a turns on and off the power switching element Q1 by the PWM control signal generated by the PWM generation circuit 14. The high side driver 3b turns on and off the power switching element Q2 by the PWM control signal generated by the PWM generation circuit 14.

  Next, the production process of the intelligent power module will be described with reference to the flowchart shown in FIG.

  First, the wafer is cut into wafer dies (step S11). This wafer die becomes a chip. Next, this chip is bonded to the substrate with a die mount agent. That is, die mounting is performed (step S12).

  Next, a wire is bonded to the chip. That is, wire bonding is performed (step S13). Thereafter, the wire and the chip are sealed with resin (step S14). Thereafter, separation / LF processing is performed (step S15). The processing of step S11 to step S15 is a product assembly process of the intelligent power module 1.

  Next, a non-defective product selection inspection of the intelligent power module 1 is performed (step S16). Thereafter, the on / off time measuring device 4 is connected to the output terminals of the pair of power switching elements Q1, Q2 and the input terminal of the IPM 1 of the intelligent power module 1. Then, the on / off time measuring device 4 measures the on delay time and the off delay time of each of the pair of power switching elements Q1 and Q2 (step S17).

  FIG. 3 is a diagram showing the definitions of the on-delay time and the off-delay time of the pair of power switching elements Q1, Q2. By the switching operation of the intelligent power module 1, the on-delay time td (on) and the off-delay time toff are set to the drain current Ic and drain-source voltage Vds of the pair of power switching elements Q1 and Q2 with respect to the signal input IN. Arise.

  The cause of the time delay is due to the output delay of the low-side driver 3a and the high-side driver 3b, the gate resistance of the pair of power switching elements Q1 and Q2, the threshold value Vth, and the input capacitance Ciss.

  As shown in FIG. 3, the on-delay time td (on) is the time from when the signal input IN is turned on until the drain current Ic reaches 10% of a certain value. The off-delay time toff is the time from when the signal input IN is turned off until the drain current Ic reaches 10% of a certain value.

  Next, the on / off time measuring device 4 communicates with the intelligent power module 1 and, as shown in FIG. 4, the measured on delay time td (on) and off delay of each of the pair of power switching elements Q1 and Q2. The time toff is written in the memory 11 (step S18).

  In this case, the on-delay time td (on) L and the off-delay time toffL of the low-side power switching element Q1, and the on-delay time td (on) H and the off-delay time toffH of the high-side power switching element Q2 are stored in the memory 11. Is written to.

  Next, as shown in FIG. 5A, the adder 12 a corresponds to the adder 12 of FIG. 1, and the low-side delay time toffH of the high-side power switching element Q <b> 2 written in the memory 11 is used. The on-delay time td (on) L of the power switching element Q1 is subtracted, and the obtained value is output to the dead time generation circuit 13 as the dead time value Td.

  The adder 12b corresponds to the adder 12 of FIG. 1, and the on-delay time td (on) H of the high-side power switching element Q2 from the off-delay time toffL of the low-side power switching element Q1 written in the memory 11. And the obtained value is output to the dead time generation circuit 13 as the dead time value Td.

  The dead time generation circuit 13 generates a dead time greater than or equal to the dead time value Td based on the dead time value Td from the adder 12a, and generates a dead time greater than or equal to the dead time value Td based on the dead time value Td from the adder 12b. Generate.

  Then, a PWM signal with an optimized dead time is output via the PWM generation circuit 14. Thereafter, the product is shipped (step S19).

  As described above, according to the intelligent power module 1 and the dead time setting device of the first embodiment, the on / off time measuring device 4 determines the on delay time and the off delay time of the power switching elements Q1 and Q2 of each product at the time of product inspection. Measure and write a dead time value tailored to each product into the memory 11 in the intelligent power module 1. In other words, since the dead time value according to each product is used, the optimum dead time can be set according to the variation of each element. Therefore, a short circuit of the upper and lower arms can be prevented.

  In the conventional circuit shown in FIG. 7, two sets of the zero current detection circuits 107 and 108 and the level shift circuit 109 are required. In the first embodiment, the memory 11 and the adder 12 are required. The zero current detection circuits 107 and 108 are not necessary. Therefore, the configuration can be simplified.

  Moreover, the actual measurement value of each power switching element Q1, Q2 changes with the change of temperature. For this reason, a value obtained by adding a temperature correction value for temperature compensation for each power switching element Q1, Q2 to the actual measurement value measured by the on / off time measuring device 4 may be stored in the memory 11.

  Thus, by adding the temperature correction value to the actual measurement value and correcting the actual measurement value, a more accurate dead time can be generated.

  In addition, there is a model in which the gate resistance of an IPM switching element is increased according to customer specifications, and the switching speed is decreased to suppress noise. Thus, when a model with a slow switching speed different from a normal switching speed model is mixed, conventionally, it is necessary to change the dead time for each model. However, according to the first embodiment, since the dead time based on the actual measurement value is stored in the memory 11 at the time of product inspection, the process of changing the dead time of the model in which the gate resistance of the switching element is increased becomes unnecessary and the management is simplified There is an advantage of being.

(Example 2)
FIG. 6 is a diagram illustrating a circuit configuration of a dead time setting device including the intelligent power module according to the second embodiment of the present invention. The dead time setting device including the intelligent power module according to the second embodiment shown in FIG. 6 corresponds to a three-phase motor as an output load, and three pairs of power switching elements Q1, Q2, Q3, Q4, Q5. Q6 is provided.

  The gates of the power switching elements Q1, Q3, and Q5 are connected to the low side driver 3c, and the gates of the power switching elements Q2, Q4, and Q6 are connected to the high side driver 3d. The drains of the power switching elements Q2, Q4, Q6 are connected to the power supply terminal VBB. The sources of the power switching elements Q1, Q3, Q5 are connected to the ground terminals LS1, LS2, LS3.

  The source of the power switching element Q2, the drain of the power switching element Q1, and the output terminal of the high side driver 3d are connected to the terminal U. The source of the power switching element Q4 and the output terminal of the high side driver 3d are connected to the terminal V1. The source of the power switching element Q6 and the output terminal of the high side driver 3d are connected to the terminal W1. The drain of the power switching element Q3 is connected to the terminal V2. The drain of the power switching element Q5 is connected to the terminal W2.

  Terminal U, terminal V1, terminal W1, terminal V2, and terminal W2 are provided for connection to each terminal of a three-phase motor (not shown).

  The memory 11 stores the actual measured values of the on-delay time and the off-delay time of each of the three pairs of power switching elements Q1 to Q6 measured by the on / off time measuring device 4a.

  The adder 12 turns off both of the pair of power switching elements for each group based on the actually measured values of the on-delay time and the off-delay time of each of the three power switching elements Q1 to Q6 stored in the memory 11. Calculate the dead time value.

  According to the dead time setting device including the intelligent power module according to the second embodiment configured as described above, three pairs of power switching elements Q1 to Q6 are provided corresponding to the three-phase motor, In addition, the dead time value at which both the pair of power switching elements are turned off can be calculated.

  Therefore, the same effect as that of the dead time setting device including the intelligent power module according to the first embodiment can be obtained, and the optimum dead time corresponding to the three-phase motor can be generated.

1 Intelligent Power Module (IPM)
2 Controller 3a Low side driver 3b High side driver 4 ON / OFF time measuring device 11 Memory 12, 12a, 12b Adder 13 Dead time generation circuit 14 PWM generation circuit Q1-Q6 Power switching element

Claims (6)

A pair of power switching elements respectively provided on the upper and lower arms;
A memory for storing an actual measured value of an on delay time and an off delay time of each of the pair of power switching elements measured by an external on / off time measuring device;
A calculation unit that calculates a dead time value at which both of the pair of power switching elements are turned off based on an actual measurement value of an on delay time and an off delay time of each of the power switching elements stored in the memory;
A dead time generation circuit that generates a dead time based on the dead time value calculated by the calculation unit;
A control circuit for generating a control signal for alternately turning on and off the pair of power switching elements based on the dead time generated by the dead time generation circuit;
A drive circuit for driving the pair of power switching elements by a control signal generated by the control circuit;
An intelligent power module comprising:   The intelligent power module according to claim 1, wherein the memory stores a value obtained by adding a temperature correction value of each power switching element to the actual measurement value measured by the on / off time measuring device. Three sets of the pair of power switching elements corresponding to a three-phase motor are provided,
The memory stores the actual measured values of the on-delay time and the off-delay time of each of the three pairs of power switching elements measured by the on-off time measuring device,
The calculation unit calculates a dead time when both of the pair of power switching elements are turned off for each group based on an actual measurement value of an on delay time and an off delay time of each of the three power switching elements stored in the memory. The intelligent power module according to claim 1, wherein a value is calculated. Intelligent power module,
An on / off time measuring device for measuring an on delay time and an off delay time of each of the pair of power switching elements;
The intelligent power module
The pair of power switching elements;
A memory for storing an actual measured value of an on delay time and an off delay time of each of the pair of power switching elements measured by the on / off time measuring device;
A calculation unit that calculates a dead time value at which both of the pair of power switching elements are turned off based on an actual measurement value of an on delay time and an off delay time of each of the power switching elements stored in the memory;
A dead time generation circuit that generates a dead time based on the dead time value calculated by the calculation unit;
A control circuit for generating a control signal for alternately turning on and off the pair of power switching elements based on the dead time generated by the dead time generation circuit;
A drive circuit for driving the pair of power switching elements by a control signal generated by the control circuit;
A dead time setting device comprising:   5. The dead time setting device according to claim 4, wherein the memory stores a value obtained by adding a temperature correction value of each power switching element to the actual measurement value measured by the on / off time measuring device. Three sets of the pair of power switching elements corresponding to a three-phase motor are provided,
The memory stores the actual measured values of the on-delay time and the off-delay time of each of the three pairs of power switching elements measured by the on-off time measuring device,
The calculation unit calculates a dead time in which each pair of power switching elements is turned off for each group based on the actual measured values of the on delay time and the off delay time of each of the three power switching elements stored in the memory. 6. The dead time setting device according to claim 4, wherein a value is calculated.

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