JP3646049B2 - Power converter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power conversion device using a high-speed switching element, and in particular, reduces the wiring inductance between the smoothing capacitor and the power conversion module, and efficiently cools the power conversion module and the smoothing capacitor. The present invention relates to a power conversion device that can be reduced in size and price.
[0002]
[Prior art]
In recent years, power converters that can change the commercial power supply to an arbitrary AC output have been remarkably developed for high-speed switching.
[0003]
As the high-speed switching element, for example, GCT or the like is often used in the current drive type, and IGBT, IEGT (Injection Enhanced Gate Transistor) or the like that is an insulated gate type in the voltage drive type, respectively.
[0004]
There are two types of these high-speed switching elements, a flat semiconductor element and a module type in which a semiconductor chip is molded with a gel material and packaged. In particular, a module type with high voltage and large capacity has been developed and put to practical use. It has begun to be.
[0005]
On the other hand, because switching operation is performed at high speed and large capacity, switching surge due to electrical equipment and wiring inductance around the switching element becomes a problem, and a low-inductance mounting structure to avoid them is becoming increasingly difficult. Is the current situation.
[0006]
FIG. 3 is a circuit diagram showing an example of a main circuit configuration of a conventional power conversion device to which this kind of general high-speed switching element is applied.
[0007]
In FIG. 3, a DC power source 1 obtained by converting an AC power source (not shown) with a rectifier (not shown) or a DC power source 1 such as a battery (not shown) is smoothed by a smoothing capacitor 2 to be a positive main circuit conductor 3P and a negative main circuit conductor 3N. An inverter comprising a power conversion module (hereinafter referred to as IPM) 4 comprising a plurality of switching elements 4U to 4Z and a gate drive substrate 9 for controlling a base signal of the switching elements 4U to 4Z. It is converted into predetermined AC power by a circuit, and further supplied to a load such as an electric motor (not shown) via AC output terminals 6 to 8 of the three phases (R, S, T) of the IPM 4.
[0008]
In FIG. 3, 2P is a positive terminal of the smoothing capacitor 2, 2N is a negative terminal of the smoothing capacitor 2, 4P is a positive input terminal which is one DC input terminal of the IPM 4, and 4N is the other DC input terminal of the IPM 4. A negative input terminal 5 and a current sensor for detecting an AC output current of the IPM 4 are shown.
[0009]
[Problems to be solved by the invention]
By the way, in the power converter configured in this way, the smoothing capacitor 2 serving as the main circuit wiring and the energy accumulated in the floating inductances of the positive and negative main circuit conductors 3P and 3N are used to switch the switching elements 4U to 4Z of the IPM 4. Spike voltage is generated when the switch is off.
[0010]
That is, particularly when the IGBTs that are the switching elements 4U to 4Z are turned off, a rapid change in the main circuit current induces a high voltage in the main circuit stray inductance, and a spike voltage in the turn-off process is generated.
[0011]
For this reason, it is necessary to reduce the stray inductance of the positive and negative main circuit conductors 3P and 3N that are wiring between the smoothing capacitor 2 and the IPM 4 as much as possible.
[0012]
In order to reduce the wiring inductance, conventionally, various methods as described below have been proposed.
[0013]
(A) A wiring that cancels the change in magnetic flux.
[0014]
(B) Widen the surface of the conductor to avoid current concentration due to the skin effect.
[0015]
(C) Minimize the wiring length.
[0016]
(D) Disperse current as parallel connection.
[0017]
However, such a method has a problem in reducing the size and cost of the apparatus.
[0018]
On the other hand, the heat density is steadily increasing due to the small size and large capacity of the device, and it is difficult to cool the switching elements 4U to 4Z against heat generation.
[0019]
In particular, when the power conversion device is a power conversion device applied for driving a motor of an electric vehicle, most of the cooling is performed by cooling with a liquid refrigerant such as a coolant, and the temperature of the liquid refrigerant also serves as cooling for the motor or the like. Therefore, it is a high temperature of 70 ° C. or higher, which makes it difficult to cool with a liquid refrigerant, which is a particular problem in miniaturizing the apparatus.
[0020]
Furthermore, there are considerable restrictions in terms of storage space and weight.
[0021]
The object of the present invention is to reduce the wiring inductance between the smoothing capacitor and the power conversion module, and to efficiently cool the power conversion module and the smoothing capacitor, thereby realizing a reduction in size and price. It is in providing the power converter device which can do.
[0022]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, a DC power source comprising a capacitor for smoothing a DC power source and a plurality of switching elements is converted into a predetermined AC power source. In a power conversion device configured to include a power conversion module, the smoothing capacitor cools the power conversion module as a configuration in which the power conversion module, the heat sink, and the smoothing capacitor are stacked in this order from top to bottom. A heat sink can be shared, and among the DC input terminal and AC output terminal of the power conversion module, at least a DC input terminal is provided on the side surface of the power conversion module so that it can be connected to the smoothing capacitor at the shortest distance .
[0023]
Therefore, in the power conversion device according to the first aspect of the present invention, the power conversion module, the heat sink, and the smoothing capacitor are stacked in three layers in this order from top to bottom, and the DC input terminal of the power conversion module and By providing at least a DC input terminal on the side surface of the power conversion module among AC output terminals, it is possible to make the shortest connection between the power conversion module and the smoothing capacitor, and between the smoothing capacitor and the power conversion module. Wiring inductance can be greatly reduced.
This makes it possible to suppress the turn-off voltage reduced, it is possible to reduce or remove the snubber circuit, it is possible to miniaturize the device, the reduction of assembly wiring man-hours to achieve a low cost.
Therefore, the surge voltage to the semiconductor element that performs high-speed switching operation can be suppressed, and an economical and highly reliable power conversion device can be obtained.
In addition, the smoothing capacitor can share the heat sink that cools the power conversion module. If the smoothing capacitor has a large ripple current and is thermally severe, or the installation space of the power conversion device is limited, downsizing is the top priority. Can be applied very effectively.
[0024]
According to a second aspect of the present invention, a capacitor for smoothing a DC power source and a power conversion module that includes a plurality of switching elements and converts the DC power source smoothed by the smoothing capacitor into a predetermined AC power source are provided. In the power conversion device configured, as a configuration in which the smoothing capacitor, the power conversion module, and the heat sink are stacked in this order from the top to the bottom, the switching elements in the power conversion module are arranged in a portion close to the heat sink side. In addition, a direct current input terminal and an alternating current output terminal of the power conversion module are provided on a side surface of the power conversion module so as to be connectable to the smoothing capacitor in the shortest distance.
[0025]
Therefore, in the power converter of the invention corresponding to claim 2, the smoothing capacitor and the power conversion module are stacked in three layers in the order of the smoothing capacitor, the power conversion module, and the heat sink from the top to the bottom. Since they are adjacent to each other, it is possible to make the shortest connection between the power conversion module and the smoothing capacitor, and it is possible to further reduce the wiring inductance between the smoothing capacitor and the power conversion module.
[0030]
Furthermore, in the invention corresponding to claim 3, in the power conversion device of the invention corresponding to claim 1 or claim 2 , the heat sink is a cooling system using a liquid refrigerant.
[0031]
Therefore, in the power conversion device according to the third aspect of the present invention, the heat sink can be made ultra-thin by adopting a cooling method using a liquid refrigerant, and the power conversion module and the smoothing capacitor can be reduced. Becomes extremely low inductance wiring, and the surge voltage can be minimized.
[0032]
As described above, the wiring inductance between the smoothing capacitor and the power conversion module can be reduced, and the power conversion module and the smoothing capacitor can be efficiently cooled to achieve downsizing and cost reduction. It becomes possible.
[0033]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0034]
(First embodiment: corresponding to claims 1, 2 and 4)
FIG. 1 is a front view illustrating a mounting configuration example of the power conversion device according to the present embodiment, and the same components as those in FIG. 3 are denoted by the same reference numerals.
[0035]
In FIG. 1, the smoothing capacitor 2, the IPM 4, and the heat sink 10 that cools the IPM 4 are stacked in three layers in the height direction.
[0036]
In other words, in this embodiment, the IPM 4, the heat sink 10, and the smoothing capacitor 2 are stacked in three layers from top to bottom.
[0037]
The IPM 4 includes switching elements 4U to 4W, 4X to 4Z, and a gate drive substrate 9.
[0038]
On the other hand, the IPM 4, the heat sink 10, and the smoothing capacitor 2 are attached by the following method.
[0039]
That is, the heat sink 10 is provided with a plurality of countersunk holes 10a and a plurality of screw holes 10b. The countersink 10a is used to attach and fix the IPM 4, and a buried metal having a screw hole below the IPM 4. Four 4a are molded and fixed with a countersunk screw 11 from a countersink 10a of the heat sink 10.
[0040]
Further, the screw hole 10 b is for fixing the smoothing capacitor 2, and is fixed to the mounting hole 2 a provided in the smoothing capacitor 2 with a screw 12.
[0041]
Further, the IPM 4 and the smoothing capacitor 2 are connected to the positive and negative terminals 2P and 2N and the positive and negative terminals 4P and 4N provided on the smoothing capacitor 2 and the IPM 4, respectively, with a positive main circuit conductor 3P and a negative main circuit conductor 3N. is doing.
[0042]
On the other hand, the positive and negative terminals 4P and 4N of the IPM 4 are provided on one side surface of the IPM 4 and connect the main circuit cable 18.
[0043]
The AC output terminals 6 to 8 of the IPM 4 are provided on the other side surface of the IPM 4 and connect the main circuit cable 17.
[0044]
Note that the heat sink 10 of the present embodiment is a cooling method using liquid refrigerant, and reference numeral 20 in FIG. 1 denotes a pipe base to which a hose for guiding the liquid refrigerant into the heat sink 10 is attached.
[0045]
Next, in the power conversion device according to the present embodiment configured as described above, the smoothing capacitor 2, the IPM 4, and the heat sink 10 are stacked in three layers in the height direction. Wiring inductance with the heat sink 10 can be reduced, and low inductance can be achieved.
[0046]
As a result, the turn-off voltage can be kept small, and the snubber circuit can be reduced or reduced, so that the cost can be reduced by downsizing the apparatus and reducing the number of assembly wiring work steps.
[0047]
In particular, the IPM 4, the heat sink 10, and the smoothing capacitor 2 are stacked in this order from top to bottom, so that the smoothing capacitor 2 can be forcibly cooled with a liquid refrigerant and the heat sink 10 that cools the IPM 4 can be shared. It can be applied extremely effectively when the ripple current of the smoothing capacitor 2 is large and thermally severe, or when the installation space of the power converter is limited and miniaturization is required with the highest priority.
[0048]
In addition, by providing the positive and negative terminals 4P and 4N of the IPM 4 and the AC output terminals 6 to 8 of the IPM 4 on the side surfaces of the IPM 4, the shortest connection between the IPM 4 and the smoothing capacitor 2 becomes possible. In addition, the wiring inductance between the smoothing capacitor 2 and the IPM 4 can be further reduced.
[0049]
On the other hand, the case of the IPM 4 generally has a length of 50 mm or more, and the switching elements 4U to 4Z housed in the case are heating elements, but in the present embodiment, the switching elements 4U to 4Z are replaced with the heat sink 10. By disposing the portion closer to the side, that is, the bottommost portion of the IPM 4, it is possible to improve the heat radiation efficiency and efficiently cool the device, and to further reduce the size of the device.
[0050]
Further, since the heat sink 10 is a cooling method using a liquid refrigerant, the heat sink 10 can be made ultra thin with a thickness of 20 mm or less, and the positive main circuit conductor 3 </ b> P serving as a wiring between the IPM 4 and the smoothing capacitor 2. The length of the negative electrode main circuit conductor 3N can be minimized, resulting in extremely low inductance wiring, and the surge voltage can be minimized.
[0051]
As described above, in the power conversion device according to the present embodiment, the wiring inductance between the smoothing capacitor 2 and the IPM 4 can be reduced to the minimum, and the inductance can be reduced.
[0052]
As a result, the turn-off voltage can be reduced, the snubber circuit can be reduced or reduced, and the cost can be reduced by downsizing the apparatus and reducing the number of assembly wiring work steps.
[0053]
Therefore, the surge voltage to the semiconductor elements 4U to 4Z that perform high-speed switching operation can be suppressed, and an economical and extremely reliable power converter can be obtained.
[0054]
(Second embodiment: corresponding to claims 1, 3 and 4)
FIG. 2 is a front view showing a mounting configuration example of the power conversion device according to the present embodiment, and the same components as those in FIG. 3 are denoted by the same reference numerals.
[0055]
In FIG. 2, the smoothing capacitor 2, the IPM 4, and the heat sink 10 that cools the IPM 4 are stacked in three layers in the height direction.
[0056]
That is, in this embodiment, the smoothing capacitor 2, the IPM 4, and the heat sink 10 are stacked in three layers from the top to the bottom.
[0057]
The IPM 4 includes switching elements 4U to 4W, 4X to 4Z, and a gate drive substrate 9.
[0058]
On the other hand, the IPM 4, the heat sink 10, and the smoothing capacitor 2 are attached by the following method.
[0059]
That is, the heat sink 10 is provided with a screw hole 10c, the IPM 4 is provided with a through hole 4b, the smoothing capacitor 2 is provided with a through hole 2b, and the screw 13 is provided in the heat sink 10 through the through hole 2b. The screw hole 10c is fastened and fixed.
[0060]
Further, the IPM 4 and the smoothing capacitor 2 are connected to the positive and negative terminals 2P and 2N and the positive and negative terminals 4P and 4N provided on the smoothing capacitor 2 and the IPM 4, respectively, with a positive main circuit conductor 3P and a negative main circuit conductor 3N. is doing.
[0061]
On the other hand, the positive and negative terminals 4P and 4N of the IPM 4 are provided on one side surface of the IPM 4 and connect the main circuit cable 18.
[0062]
The AC output terminals 6 to 8 of the IPM 4 are provided on the other side surface of the IPM 4 and connect the main circuit cable 17.
[0063]
Note that the heat sink 10 of the present embodiment is a cooling method using liquid refrigerant, and reference numeral 20 in FIG. 2 denotes a pipe base to which a hose for guiding the liquid refrigerant into the heat sink 10 is attached.
[0064]
Next, in the power conversion device according to the present embodiment configured as described above, the smoothing capacitor 2, the IPM 4, and the heat sink 10 are stacked in three layers in the height direction. Wiring inductance with the heat sink 10 can be reduced, and low inductance can be achieved.
[0065]
As a result, the turn-off voltage can be kept small, and the snubber circuit can be reduced or reduced, so that the cost can be reduced by downsizing the apparatus and reducing the number of assembly wiring work steps.
[0066]
In particular, since the smoothing capacitor 2, the IPM 4, and the heat sink 10 are stacked in this order from the top to the bottom, the IPM 4 can be efficiently cooled with the liquid refrigerant, the ripple current of the smoothing capacitor 2, the surge voltage of the IPM 4 When the installation space is relatively large, for example, the present invention can be applied very effectively as a power converter for an electric vehicle.
[0067]
In addition, by providing the positive and negative terminals 4P and 4N of the IPM 4 and the AC output terminals 6 to 8 of the IPM 4 on the side surfaces of the IPM 4, the shortest connection between the IPM 4 and the smoothing capacitor 2 becomes possible. In addition, the wiring inductance between the smoothing capacitor 2 and the IPM 4 can be further reduced.
[0068]
Furthermore, since the smoothing capacitor 2 and the IPM 4 are adjacent to each other, the shortest connection between the IPM 4 and the smoothing capacitor 2 becomes possible, and the wiring inductance between the smoothing capacitor 2 and the IPM 4 is further reduced. Can do.
[0069]
On the other hand, the case of the IPM 4 generally has a length of 50 mm or more, and the switching elements 4U to 4Z housed in the case are heating elements, but in the present embodiment, the switching elements 4U to 4Z are replaced with the heat sink 10. By disposing the portion closer to the side, that is, the bottommost portion of the IPM 4, it is possible to improve the heat radiation efficiency and efficiently cool the device, and to further reduce the size of the device.
[0070]
Further, since the heat sink 10 is a cooling method using a liquid refrigerant, the heat sink 10 can be made ultra thin with a thickness of 20 mm or less, and the positive main circuit conductor 3 </ b> P serving as a wiring between the IPM 4 and the smoothing capacitor 2. The length of the negative electrode main circuit conductor 3N can be minimized, resulting in extremely low inductance wiring, and the surge voltage can be minimized.
[0071]
As described above, in the power conversion device according to the present embodiment, the wiring inductance between the smoothing capacitor 2 and the IPM 4 can be further reduced to the minimum, and the inductance can be reduced.
[0072]
As a result, the turn-off voltage can be reduced, the snubber circuit can be reduced or reduced, and the cost can be reduced by downsizing the apparatus and reducing the number of assembly wiring work steps.
[0073]
Therefore, the surge voltage to the semiconductor elements 4U to 4Z that perform high-speed switching operation can be suppressed, and an economical and extremely reliable power converter can be obtained.
[0074]
(Other embodiments)
In each of the above embodiments, the case where both the positive and negative terminals 4P and 4N of the IPM 4 and the AC output terminals 6 to 8 of the IPM 4 are provided on the side surfaces of the IPM 4 is described. , Only the negative terminals 4P and 4N may be provided on the side surface of the IPM 4.
[0075]
【The invention's effect】
As described above, according to the power conversion device of the present invention, the wiring inductance between the smoothing capacitor and the power conversion module can be reduced, and the power conversion module and the smoothing capacitor can be efficiently cooled. This makes it possible to reduce the size and price.
[0076]
Therefore, it is possible to suppress a surge voltage to a semiconductor element that performs a high-speed switching operation, and it is possible to provide an economical and extremely reliable power conversion device.
[0077]
As described above, the wiring inductance between the smoothing capacitor and the power conversion module can be reduced, and the power conversion module and the smoothing capacitor can be efficiently cooled to achieve downsizing and cost reduction. It becomes possible.
[Brief description of the drawings]
FIG. 1 is a front view showing a first embodiment of a power converter according to the present invention.
FIG. 2 is a front view showing a second embodiment of a power converter according to the present invention.
FIG. 3 is a circuit diagram showing a main circuit configuration example of a conventional power converter.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... DC power supply 2 ... Smoothing capacitor 2P ... Positive electrode terminal 2N of smoothing capacitor 2 ... Negative electrode terminal 3P of smoothing capacitor 2 ... Positive electrode main circuit conductor 3N ... Negative electrode main circuit conductor 4 ... IPM
4U ... switching element 4V ... switching element 4W ... switching element 4X ... switching element 4Y ... switching element 4Z ... switching element 4P ... IPM4 positive input terminal 4N ... IPM4 negative input terminal 4a ... fill 5 ... current sensor 6 ... AC output Terminal 7 ... AC output terminal 8 ... AC output terminal 9 ... Gate drive substrate 10 ... Heat sink 10a ... Countersunk hole 10b ... Screw hole 10c ... Screw hole 11 ... Countersunk screw 12 ... Screw 13 ... Screw 17 ... Main circuit cable 18 ... Main Circuit cable 20 ... Pipe cap.

Claims (3)

In a power conversion device configured to include a capacitor for smoothing a DC power source and a power conversion module that converts a DC power source that is made of a plurality of switching elements and smoothed by the smoothing capacitor into a predetermined AC power source,
As a configuration in which the power conversion module, the heat sink, and the smoothing capacitor are stacked in this order from top to bottom, the smoothing capacitor can share a heat sink that cools the power conversion module, and the DC input terminal of the power conversion module Among the AC output terminals, at least a DC input terminal is provided on a side surface of the power conversion module so that it can be connected to the smoothing capacitor in the shortest distance . In a power conversion device configured to include a capacitor for smoothing a DC power source and a power conversion module that converts a DC power source that is made of a plurality of switching elements and smoothed by the smoothing capacitor into a predetermined AC power source,
As a configuration in which the smoothing capacitor, the power conversion module, and the heat sink are stacked in this order from the top to the bottom, the switching element in the power conversion module is disposed in a portion near the heat sink, and the power conversion module A power conversion apparatus, wherein a DC input terminal and an AC output terminal are provided on a side surface of the power conversion module so as to be connected to the smoothing capacitor at a shortest distance . In the power converter device according to claim 1 or 2 ,
The power converter is characterized in that the heat sink is a cooling system using a liquid refrigerant .

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