JP5152136B2 - Semiconductor power module - Google Patents

Description

  The present invention relates to a semiconductor power module that suppresses switching noise generated during switching of a power semiconductor element.

In power converters such as an AC motor drive device (so-called inverter) and an uninterruptible power supply (UPS), power conversion is performed by switching power semiconductor elements.
FIG. 4 is a circuit diagram of this type of power converter. In FIG. 4, 1 is a DC power source, 2U, 2V, and 2W are semiconductor power modules in which two IGBT (Insulated Gate Bi-polar Transistors) are connected in series as power semiconductor elements in which freewheeling diodes are connected in antiparallel. Is a motor as a load. In the semiconductor power modules 2U, 2V, and 2W of each phase, the DC power of the DC power source 1 is converted into AC power and supplied to the motor 3 by alternately switching the IGBTs of the upper and lower arms.
In FIG. 4, the illustration of the IGBT gate drive circuit is omitted.
As a switching method of the IGBT, a PWM (Pulse Width Modulation) control method in which the external control circuit 5 determines the switching pattern by comparing the magnitude relationship between the reference sine wave 5a and the output voltage command 5b by the comparison operation unit 5c is good. Are known. The switching pattern is sent to the drive circuit 4, converted into a gate signal for the IGBT, and output to the power modules 2U, 2V, 2W. The IGBT gate drive circuit is not shown.

Here, the power semiconductor elements such as the IGBT and the freewheeling diode are mounted in one package to constitute the semiconductor power modules 2U, 2V, and 2W, thereby simplifying the device structure, assembling work, and wiring work. Simplification and element cooling are facilitated.
In recent years, in addition to IGBTs and freewheeling diodes, a power module called an intelligent power module (IPM) mounted in a single container including a drive circuit 4 for driving the IGBT has been developed. Efforts are being made to further simplify the configuration of the device.
FIG. 5 is a circuit diagram of a power conversion device having the intelligent power module 2A. This power module 2A includes an IGBT, a freewheeling diode, a diode, a drive circuit 4 and the like, and includes DC input terminals 2a and 2b connected to the DC power supply 1, AC output terminals 2c and 2d connected to the load 3, and so on. 2e, a connection terminal 2f of the braking resistor 11, and a control input terminal 2g connected to the control circuit 5.
In the power converter provided with the conventional semiconductor power modules 2U, 2V, 2W and the intelligent power module 2A described above, excessive switching noise occurs when the power semiconductor element is switched, and other power converters installed around the power converter are provided. There was a risk of malfunctions such as equipment malfunctioning and noise.

The switching noise can be mainly classified into two types.
The first switching noise is normal mode noise due to a normal mode high-frequency current flowing in a closed loop composed of a power module and a DC power supply. FIG. 6A shows a closed loop 10N through which the normal mode noise current flows. In FIG. 6A, reference numeral 2 denotes a power module representative of the power modules for one phase in the semiconductor power modules 2U, 2V, 2W and the intelligent power module 2A described above.
In this normal mode, switching of the power semiconductor element causes LC resonance due to the stray inductance of the wiring constituting the closed loop 10N and the junction capacitance of the power semiconductor element, and a high-frequency noise current due to this resonance flows through the closed loop 10N. Mode.
The second switching noise is common mode noise due to a noise current flowing through the ground through the stray capacitance inside the power module and the power converter. FIG. 7A shows a closed loop 10C through which this common mode noise current flows.
This common mode is a mode in which the stray capacitances 7 and 8 are charged and discharged at a high frequency by a high voltage change (dV / dt) caused by switching of the power semiconductor element, and this high frequency charge / discharge current flows through the closed loop 10C through the ground. . In this mode, noise current may flow out to the DC power supply 1 side, or noise may be radiated as radio waves.

In order to suppress the above-described normal mode noise current and common mode noise current, conventionally, an impedance such as an inductance is generally added to the noise current loop.
FIG. 6B shows a conventional technique in which an inductance 6a is provided in series with the power module 2 in order to suppress the normal mode noise current.
FIG. 7B shows a conventional technique in which the positive and negative sides of the DC input terminal of the power module 2 are collectively connected to both ends of the DC power source 1 via the inductance 6b in order to suppress the common mode noise current. According to this prior art, since the inductance 6b works as an impedance component with respect to the noise current flowing to the ground side through the stray capacitances 7 and 8 in FIG. 7A, the noise current can be suppressed.
6B and 7B, the normal mode noise current and the common mode noise current can be temporarily suppressed.
In this case, if the inductance for suppressing the noise current can be arranged at a position closer to the semiconductor element, it is effective for downsizing and packaging of the entire circuit. Therefore, the technology described in the patent document as described below is provided. Yes.

First, Patent Document 1 below discloses means for suppressing common mode noise current. That is, the means surrounds the periphery of the positive and negative electrodes of a DC power supply inner lead (connection line) of a semiconductor device (IC chip) connected to a DC power supply with an annular composite magnetic material as a filter element. Is enclosed in a package.
Patent Document 2 below discloses a noise reduction element made of an amorphous magnetic alloy that is externally fitted to a lead portion of various semiconductor elements such as a diode or molded integrally.

JP 2000-58740 A (Claim 1, FIG. 1, etc.) JP-A-9-12116 (Claim 1, Claim 4, FIG. 1, FIG. 2, etc.)

However, in the prior art described in Patent Document 1, since the composite magnetic material used as the filter element is sealed in the package, the composite magnetic material cannot be exchanged (inductance value changed).
Usually, the frequency of switching noise varies depending on external circuit conditions (wiring stray inductance and stray capacitance). For this reason, when a filter element is added to a semiconductor element to reduce noise, it is desirable that the filter element be mounted outside the package and replaced as necessary. However, this is not possible with Patent Document 1.
Moreover, in the prior art of patent document 1, since a composite magnetic material is incorporated in a package, there exists a problem that a package enlarges.
Furthermore, the prior art described in Patent Document 2 is assumed to be applied to a relatively small capacity semiconductor element having a lead wire, and cannot be applied to a medium / large capacity power module as it is. . Moreover, since it is common to connect large wiring components, such as a copper bar with a large area, to the terminal of a power module so that a big electric current can be sent, the noise reduction element as described in patent document 2 is used. It was impossible to fit the terminals of the power module.
Accordingly, an object of the present invention is to provide a semiconductor power module in which a magnetic member used as a filter element can be replaced as necessary.

Another object of the present invention is to provide a semiconductor power module that enables a package to be miniaturized.
Furthermore, another object of the present invention is applicable regardless of the individual power semiconductor elements or the capacity of the entire module, and the semiconductor power module for one phase of the upper and lower arms, the intelligent power module with a built-in driving circuit, and the like. It is to provide a possible semiconductor power module.

In the present invention, in a semiconductor power module for a power conversion device that converts DC power or AC power by switching power semiconductor elements, an annular magnetic member is disposed so as to surround terminals connected to the power semiconductor elements. To do. Thereby, the common mode noise current and the normal mode noise current flowing through the terminal as the power semiconductor element is switched can be effectively suppressed.
The semiconductor power module of the present invention includes, for example, a semiconductor power module in which a power semiconductor element for one phase of an upper and lower arm constituting a power converter is built in a module package, and the power semiconductor element and its drive circuit in the module package Includes built-in power modules (so-called intelligent power modules).
In short, the present invention has any function and structure as long as the power semiconductor element is built in the module package and the terminal connected to the power semiconductor element is arranged outside the module package. It may be a semiconductor power module.
The annular magnetic member is arranged in a magnetic member arrangement space formed around the terminal, and this magnetic member arrangement space forms a recess around the terminal or projects the terminal from the module package. Formed by.

  The terminals surrounded by the annular magnetic member include a terminal for transmitting DC power such as a DC input terminal, a terminal for transmitting AC power such as an AC output terminal, and a control for a power semiconductor element. This corresponds to a control terminal such as a control input terminal for inputting a signal.

According to the present invention, by attaching the annular magnetic member to the terminals arranged outside the module package, the common mode noise current and the normal mode noise current due to the annular magnetic member are suppressed without increasing the size of the package. be able to.
In addition, since the inductance required for the filter element also changes according to the frequency of the switching noise that depends on the external circuit conditions, when the external circuit conditions change, it may be replaced with an annular magnetic member having an optimum inductance. . At that time, since the annular magnetic member is externally fitted to the terminal, the replacement work can be easily performed.

It is a perspective view which shows embodiment at the time of applying this invention to an intelligent power module. It is a perspective view which shows embodiment at the time of applying this invention to an intelligent power module. It is a perspective view which shows embodiment at the time of applying this invention to an intelligent power module. It is a side view of FIG. 1C. It is a perspective view which shows embodiment at the time of applying this invention to an intelligent power module. It is a circuit diagram which shows the path | route of the noise current in FIG. 2A. It is a perspective view showing an embodiment at the time of applying the present invention to a semiconductor power module. It is a perspective view showing an embodiment at the time of applying the present invention to a semiconductor power module. It is a perspective view showing an embodiment at the time of applying the present invention to a semiconductor power module. It is a perspective view showing an embodiment at the time of applying the present invention to a semiconductor power module. It is a perspective view which shows the modification of the annular magnetic member at the time of applying this invention to a semiconductor power module. It is a circuit diagram of the power converter device which has a semiconductor power module of a prior art. It is a circuit diagram of the power converter device which has an intelligent power module of a prior art. It is a circuit diagram explaining the loop of the normal mode noise current of a prior art. It is a conventional circuit diagram for suppressing the normal mode noise current of the prior art. It is a circuit diagram explaining the loop of the common mode noise current of a prior art. It is the conventional circuit diagram for suppressing the common mode noise current of a prior art.

The best mode for carrying out the present invention will be described below with reference to the drawings.
First, FIG. 1A, FIG. 1B, and FIG. 1C are perspective views showing an embodiment when the present invention is applied to an intelligent power module.
In FIG. 1A, 2B is an intelligent power module. For example, the resin module package 21 incorporates an IGBT, a freewheeling diode, a diode, and a drive circuit, as in the intelligent power module 2A shown in FIG. Further, around the module package 21, there are provided DC input terminals 2a, 2b, AC output terminals 2c, 2d, 2e connected to internal circuit components, a connection terminal 2f of the braking resistor 11, and a control input terminal 2g. It has been. The connection state between the circuit components such as the IGBT and the terminals 2a to 2g is the same as that of the intelligent power module 2A in FIG.
In this embodiment, the terminals 2a to 2g are projected slightly above the surface of the module package 21, and the recesses 2h are formed around the terminals 2a to 2g, thereby inserting the following annular magnetic members. A magnetic member arrangement space is formed for this purpose.
FIG. 1B shows an intelligent power module 2C in which an annular magnetic member 6c is inserted so as to collectively surround the DC input terminals 2a and 2b. In this example, the annular magnetic member 6c is operated as an inductance for removing common mode noise.

FIG. 1C shows an intelligent power module 2D in which an annular magnetic member 6d is fitted so as to surround the DC input terminal 2b on the negative electrode side. In this example, the annular magnetic member 6d is operated as an inductance for removing normal mode noise.
Of course, the annular magnetic member 6d may be fitted so as to surround the DC input terminal 2a on the positive electrode side or other terminals.
As the annular magnetic members 6c and 6d, for example, a ferrite sintered body molded in an annular shape is used.
FIG. 1D is a side view of FIG. 1C viewed from the lateral direction (direction facing the terminals 2f, 2a, 2b). The annular magnetic member 6d is inserted between the copper bus bar 9 connecting the terminals 2a, 2b, and 2f and the intelligent power module 2D.
As shown in FIGS. 1A to 1D, the module package 21 is enlarged by inserting the annular magnetic member 6 c or 6 d so as to surround the terminals 2 a to 2 g arranged outside the module package 21. Noise countermeasures can be implemented.
Further, since the annular magnetic member is arranged outside the module package 21, the annular magnetic member having a desired inductance matched to the noise frequency can be replaced and mounted.

In order to set the inductance value of the annular magnetic member to a desired value, for example, the inductance value may be changed while changing the material (relative magnetic permeability) of the annular magnetic member and maintaining the same outer shape. Alternatively, a thin annular magnetic member may be prepared and the inductance value may be changed by adjusting the number of insertions as necessary.
Next, FIG. 2A is a perspective view of an intelligent power module 2E in which a round-shaped annular magnetic member 6e is inserted into the control input terminal 2g.
In this case, as shown in the figure, by slightly projecting the control input terminal 2g from the surface of the module package 21, a magnetic member arrangement space is inevitably formed around the control input terminal 2g. In addition, due to the structure, the height of the control input terminal 2g is the module package 21
If the surface is substantially the same, the recess may be formed around the control input terminal 2g to form the magnetic member arrangement space.
The path of the common mode noise current in FIG. 2A is shown in FIG. 2B. In FIG. 2B, only the power semiconductor elements for one phase of the upper and lower arms are shown in the circuit configuration inside the module package 21.
The common mode noise current may flow through the control input terminal 2g of the intelligent power module 2E and through the stray capacitance 8 between the power module and the earth or between the control circuit 5 and the earth, and the annular magnetic member 6e is connected to the noise current path 10C. The noise current can be suppressed by inserting.

If a concave portion is provided around the control input terminal 2g and the annular magnetic member 6e is inserted into the concave portion, the annular magnetic member 6e can be used when wiring by the copper bus bar 9 shown in FIG. 1D or wiring using a printed board is performed. It won't get in the way.
Next, FIG. 3A, FIG. 3B, and FIG. 3C are perspective views showing an embodiment of a semiconductor power module that incorporates power semiconductor elements for one phase of the upper and lower arms. These power modules correspond to, for example, the semiconductor power modules 2U, 2V, and 2W in FIG. 4 described above.
In the semiconductor power module 2F shown in FIG. 3A, 12a is a positive side DC input terminal, 12b is a negative side DC input terminal, 12c is an AC output terminal, and 12g is a control input terminal. Arrangement order and arrangement of each terminal are arbitrary. It can be changed. Also in this embodiment, each terminal 12a, 12b, 12c, 12g protrudes from the module package 12 to form a recess 12h around each terminal 12a, 12b, 12c, 12g, thereby inserting the annular magnetic member. The magnetic member arrangement space is held.
FIG. 3B shows a semiconductor power module 2G in which the annular magnetic material 6f is fitted around the DC input terminals 12a and 12b together, and is a structure for suppressing common mode noise by the annular magnetic material 6f. .

FIG. 3C shows the semiconductor power module 2H in which the annular magnetic material 6g is inserted only into the positive side DC input terminal 12a, and is a structure for suppressing normal mode noise by the annular magnetic material 6g. Of course, the annular magnetic material 6g may be fitted into the negative side DC input terminal 12b.
Since the annular magnetic materials 6f and 6g can be inserted with the space above each terminal open, the annular magnetic materials 6f and 6g are obstructive when wiring is performed by connecting a copper bus bar or the like to each terminal. There is no fear, and since the annular magnetic materials 6f and 6g can be easily insulated, it is possible to easily prevent the electrodes from being short-circuited. In this case, as an insulating method of the annular magnetic materials 6f and 6g, there is a method of covering the surfaces of the annular magnetic materials 6f and 6g with an insulating resin.
Next, FIG. 3D is an example in which the positive electrode side DC input terminals 12a and the negative electrode side DC input terminals 12b of the plurality of semiconductor power modules 2H are respectively connected by copper bus bars 9a and 9b. Since these copper bus bars 9a and 9b can be connected to the respective terminals while being placed on the upper surface of the annular magnetic material 6f, conventional parts are used without changing the shape and structure of the copper bus bars 9a and 9b. be able to.
As described above, the embodiment of FIGS. 3A to 3D also has a structure in which the annular magnetic materials 6f and 6g are fitted so as to surround each terminal. Can be miniaturized. It is also easy to replace and mount the annular magnetic member having a desired inductance corresponding to the noise frequency by the same method as described above.

Furthermore, in order to reduce both normal mode noise and common mode noise at the same time, the structures shown in FIGS. 3B and 3C may be combined, or sun-shaped annular magnetic members 6h and 6i as shown in FIG. 3E may be used. .
In each of the above-described embodiments, when the noise current path includes an AC output terminal, an annular magnetic body may be inserted so as to surround the AC output terminal.
Further, depending on the function of the power converter (DC-DC conversion, AC-DC conversion, etc.), a countermeasure against noise may be taken by inserting an annular magnetic body into the DC output terminal or AC input terminal.
In addition, in each of the embodiments, an annular magnetic body integrally formed with a circle shape or a square shape is illustrated as the annular magnetic body. However, the U-shaped magnetic body and the I-shaped magnetic body are combined to form an annular shape as a whole. However, the same effect can be obtained.
In each embodiment, the magnetic member arrangement space is formed around all the terminals of the power module. However, the magnetic member arrangement space is provided only around the terminals where noise current flows and noise current needs to be suppressed. It is enough to form.
Furthermore, as described above, the present invention only needs to form a magnetic member arrangement space around the terminals arranged outside the module package, so that a structure in which a recess is formed around the terminals, and a structure in which the terminals themselves are projected. All belong to the technical scope of the present invention.

1: DC power supply 2, 2U, 2V, 2W, 2F, 2G, 2H: Semiconductor power modules 2A, 2B, 2C, 2D, 2E: Intelligent power modules 2a, 2b, 12a, 12b: DC input terminals 2c, 2d, 2e 12c: AC output terminal 2f: Braking resistor connection terminal 2g, 12g: Control input terminal 2h, 12h: Recess 3: Motor 4: Drive circuit 5: Control circuit 5a: Reference sine wave 5b: Output voltage command 5c: Comparison Arithmetic units 6a, 6b: inductance 6c, 6d, 6e, 6f, 6g, 6h, 6i: annular magnetic member 7, 8: stray capacitance 9, 9a, 9b: copper bus bar 10C, 10N: noise current path 11: braking resistance 12, 21: Module package 1

Claims (4)

In a semiconductor power module in which a power semiconductor element is built in a module package, and a terminal connected to the power semiconductor element is disposed outside the module package,
A magnetic member arrangement space is formed by a recess provided around the terminal, and an annular magnetic member for reducing a noise current flowing through the terminal is arranged so as to surround the terminal in the magnetic member arrangement space.
A semiconductor power characterized in that the annular magnetic member is mounted in the magnetic member arrangement space by changing the relative permeability, exchanging the one having the same outer shape and having the inductance corresponding to the noise frequency. module. In a semiconductor power module in which a power semiconductor element is built in a module package, and a terminal connected to the power semiconductor element is disposed outside the module package,
A magnetic member arrangement space is formed by a recess provided around the terminal, and an annular magnetic member for reducing a noise current flowing through the terminal is arranged so as to surround the terminal in the magnetic member arrangement space.
The semiconductor magnetic module according to claim 1, wherein the annular magnetic member is a thin annular magnetic member, and is mounted in the magnetic member arrangement space with the number of insertions adjusted so as to have an inductance corresponding to a noise frequency . In the semiconductor power module according to claim 1 or 2,
A semiconductor power module, wherein the terminal is protruded from the module package to form a magnetic member arrangement space around the terminal, and the annular magnetic member is arranged in the magnetic member arrangement space. In the semiconductor power module according to any one of claims 1 to 3,
The terminal is at least one of a terminal for transmitting DC power, a terminal for transmitting AC power, and a control terminal for transmitting a control signal for the power semiconductor element. Semiconductor power module.

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