JP2008220060A - Power converter and current sensor - Google Patents

Abstract

The present invention provides a power converter that can be used in an environment where vibration and temperature change are severe, such as in-vehicle use.
A power module is connected between a DC power source and an AC power load of a power converter that drives an AC power load from a DC power source, and first semiconductor elements 15a, 15b for driving the power module 1 are connected. The second semiconductor elements 16a, 16b, and 16c constituting the current sensor circuit that detects the current of the power module 1 are mounted on the power module driving substrate 12 on which 15c, 15d, 15e, and 15f are mounted.
[Selection] Figure 2

Description

  The present invention relates to a power conversion device and a current sensor for driving an AC power load from a DC power source.

  In recent years, various hybrid vehicles equipped with an internal combustion engine, an electric motor, and a power storage device such as a battery have been proposed. In such a hybrid vehicle, the internal combustion engine and the electric motor are controlled according to the traveling state of the vehicle to travel.

  In an electric motor in such a hybrid vehicle, generally, a direct current output from a power storage device is converted into an alternating current by a power conversion device, more precisely, a power module in the power conversion device, and the alternating current is supplied to the electric motor. It is operated by.

  In the power converter, an alternating current flowing through a bus bar extending from the power module (three-phase inverter circuit module) is detected by a current sensor, and the power converter is controlled based on the detected signal or the like. Yes.

  By the way, conventionally, an in-vehicle power conversion device has been disclosed in which a current sensor substrate and a power module driving substrate on which a semiconductor element constituting a power module driving circuit is mounted are separated (see, for example, Patent Document 1). ).

JP 2006-81111 A (summary column, FIG. 11)

  However, in the in-vehicle power conversion device disclosed in Patent Document 1, since the power module drive substrate and the current sensor substrate are separate structures, there is a limit to downsizing, and the current sensor substrate Leading pins for connecting the mounted semiconductor elements and the semiconductor elements mounted on the power module drive board are required, increasing the number of assembly steps, and this is an increase in the cost of manufacturing in-vehicle power converters. It was.

  The present invention has been made to solve the above problems, and a first object of the invention is to provide a power converter that realizes miniaturization and cost reduction.

Moreover, the place made into the 2nd objective is to provide the power converter device which can respond to the use in the environment where vibration and temperature change are severe, such as for vehicle-mounted use.

A third object is to provide a current sensor that can be used in an environment where vibration and temperature change are severe such as in-vehicle use.

  The power conversion device according to the present invention is a power conversion device that drives an AC power load from a DC power source, and that drives a power module connected between the DC power source and the AC power load, and the power module. A power module driving board on which a first semiconductor element is mounted and a current sensor for detecting a current of the power module are mounted, and a second semiconductor element constituting a circuit of the current sensor is mounted on the power module driving board. It is a thing.

  According to the present invention, since the second semiconductor element constituting the circuit of the current sensor is mounted on the power module driving board on which the first semiconductor element for driving the power module is mounted, the first semiconductor element is mounted. The substrate on which the substrate and the second semiconductor element are mounted can be shared, and a power conversion device having both a reduction in size and a reduction in cost can be obtained.

  Exemplary embodiments of a power conversion device and a current sensor according to the present invention will be described below with reference to the accompanying drawings. For convenience of explanation, an in-vehicle power conversion device will be described as an example.

Embodiment 1 FIG.
1-3 is a figure explaining Embodiment 1 of this invention, FIG. 1 is a top view explaining the power module part of the vehicle-mounted power converter device. In FIG. 1, reference numeral 1 denotes a power module. The power module 1 is composed of switching elements 1a, 1b, 1c molded with resin or the like, and power is controlled by appropriately controlling these switching elements 1a, 1b, 1c. A three-phase inverter circuit that performs conversion is configured.

  The power module 1 is disposed in the case 2 and is connected to the DC side terminal 3 and the AC side terminal 4 provided in the case 2 by bus bars 5 and 6. The power module 1 and the bus bars 5 and 6 are fixed by screws 7 and 8, respectively. In addition, a holder 9 that holds a power module drive board, which will be described later, is formed at desired locations (eight locations in the figure) of the case 2. The DC side terminal 3 is connected to a DC power source (not shown), and the AC side terminal 4 is connected to an AC load (not shown).

  In the vicinity of the AC side terminal 4 of the power module 1, an iron core 10 for a current sensor that detects a current of the power module 1 is arranged, and the iron core 10 is arranged so as to surround the periphery of the bus bar 6. It has become. In other words, the bus bar 6 is configured to penetrate the iron core 10. The switching elements 1a, 1b, and 1c constituting the power module 1 are provided with signal terminals 11a, 11b, and 11c, respectively, and are connected to a first semiconductor element mounted on a power module driving board described later.

  FIG. 2 is a plan view showing a state in which the power module drive substrate is attached to the holder 9 of the case 2. As understood from this figure, the power module drive substrate 12 is held by the holder 9 and fixed by screws 13. The power module 1 is housed in the case 2 by fixing the power module drive substrate 12 to the holder 9 of the case 2.

  In one side portion of the power module driving substrate 12, a plurality of slits 14a to 14f parallel to the central portion from the side are formed, and an area of the power module driving substrate 12 where the slits 14a to 14f are not formed. The first semiconductor elements 15a to 15f for driving the power module 1 are mounted. Further, second semiconductor elements 16a to 16c constituting a circuit of a current sensor are mounted in an area formed between the slits 14a to 14f formed in the power module drive substrate 12.

3 is a cross-sectional view from the direction of arrow A in FIG. As shown in FIG. 3, the bus bar 6 passes through the iron core 10, and magnetic flux due to the current flowing through the bus bar 6 is collected by the iron core 10. A gap G is formed in the iron core 10, and the magnetic flux collected by the iron core 10 is converted into an electric signal by the Hall element 18 inserted in the gap G. The electrical signal from the hall element 18 is output to the second semiconductor elements 16a to 16c.

  By the way, in general, when a semiconductor element is subjected to mechanical stress, a piezo effect is generated in which the resistance of the semiconductor element changes, and its characteristics change. Therefore, it is necessary to devise a circuit for handling an analog signal such as a current sensor so as not to be subjected to mechanical stress. In particular, in an in-vehicle environment where the environment is severe, a screw for fixing the substrate is loosened due to vibration or temperature change, causing substrate distortion, and mechanical stress is likely to be generated due to the substrate distortion. It is known that this tendency is that the larger the substrate size, the larger the substrate distortion, and the more easily mechanical stress is applied to the semiconductor element mounted on the substrate.

  Here, the substrate of the area formed between the slits 14a to 14f according to the first embodiment, that is, the current sensor substrates 17a to 17c is shared with the power module driving substrate 12, and the substrate is the slits 14a to 14f. It is divided and formed by. Therefore, the second semiconductor elements 16a to 16c mounted in this area can obtain the same effect as that mounted on a small-sized substrate. That is, since the power module drive substrate 12 is large in size, the substrate is likely to be distorted. However, even if the entire substrate is distorted, the current sensor substrates 17a to 17c partitioned from the substrate body by the slits 14a to 14f are not distorted. . Therefore, even though the current sensor substrates 17a to 17c and the power module drive substrate 12 are configured by the same substrate and shared, the second semiconductor element 16a configuring the current sensor circuit mounted on the substrate is used. Since ˜16c is not subjected to mechanical stress, the characteristics do not change.

  As described above, the in-vehicle power conversion device according to the first embodiment configures the circuit of the current sensor even though the power module driving substrate 12 and the current sensor substrate 17 are configured by the same substrate and shared. The second semiconductor elements 16a to 16c become a power conversion device having a structure that is not subjected to mechanical stress, and can be applied to an environment where the vibration and temperature change are severe such as in-vehicle use. In addition, the power module drive board 12 and the current sensor boards 17a to 17c are formed of the same board and are used in common, so that the power conversion device can be reduced in size and the number of assembly steps can be reduced and the cost can be reduced.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described. FIG. 4 is a plan view showing the in-vehicle power converter according to the second embodiment. In FIG. 4, the power module drive substrate 12 is mounted with first semiconductor elements 15a to 15f for driving the power module 1, and second semiconductor elements 16a to 16c constituting a circuit of a current sensor. ing. Further, on one side portion of the power module driving substrate 12, a slit 40 constituted by a first slit 40a extending from one side of the power module driving substrate 12 toward the central portion and a second slit 40b intersecting with the first slit 40a. Is formed. That is, a T-shaped slit 40 is formed in part on the power module drive substrate 12. A second semiconductor element is mounted on a part of the power module drive substrate 12 partitioned by the T-shaped slit 40, and this partitioned portion functions as current sensor substrates 17a to 17c. Since other parts are the same as those in the first embodiment, the same reference numerals are given and description thereof is omitted.

  Here, the second semiconductor elements 16a to 16c constituting the circuit of the current sensor are mounted on the substrate section partitioned by the T-shaped slit 40, in other words, the current sensor substrates 17a to 17c. The same effect as that mounted on a small-sized substrate can be obtained. Therefore, even if the power module drive substrate 12 is distorted, the substrate portion partitioned by the T-shaped slit 40 is not distorted because the connected portion is small. Note that both ends of the T-shaped portion are fixed by screws 41 in order to prevent a reduction in vibration resistance due to the small connecting portion.

  For these reasons, the current sensor boards 17a to 17c and the power module drive board 12 are formed of the same board and shared, but the second semiconductor elements 16a to 16c constituting the current sensor circuit are mechanical. It can be set as the power converter device of the structure which does not receive a static stress. For this reason, it can be applied to an environment where the vibration and temperature change are severe such as for in-vehicle use, and a small-sized and low-cost power conversion device can be realized.

Embodiment 3 FIG.
Next, a third embodiment of the present invention will be described. 5-7 is a figure explaining a current sensor, Comprising: The example which comprised three current sensors in the integral shape is shown. FIG. 5 is a plan view of the current sensor. In this figure, reference numeral 50 denotes a three-piece current sensor substrate, and the current sensor substrate 50 is provided with slits 51a to 51f. The semiconductor elements 52a to 52c to be configured are mounted.

  FIG. 6 is a view seen from the direction of arrow B in FIG. 5. As shown in FIG. 6, the current sensor of the third embodiment includes an iron core 10 that collects magnetic flux, a hall element 18 that converts magnetic flux into an electrical signal, A case 53 for fixing the current sensor substrate 50 and the iron core 10 is provided, and the current sensor substrate 50 is fixed to the case 53 with screws 54. Further, a current sensor substrate 50 and leads 55 for connection to an external substrate such as a power module drive substrate are provided.

7 is a view seen from the direction of arrow C in FIG. 6. As shown in this figure, the lead 55 is insert-molded in the case 53. FIG.

Here, since the semiconductor elements 52a to 52c constituting the circuit of the current sensor are mounted between the slits 51a to 51f, the effect as described in the first embodiment can be obtained, and the circuit of the current sensor can be obtained. Since the semiconductor elements 52a to 52c are configured so as not to be subjected to mechanical stress, the semiconductor elements 52a to 52c can be mounted in an environment where the vibration and temperature change are severe such as in-vehicle. In addition, since the three current sensors have an integral structure, the number of assembling steps for the power conversion device is reduced, which contributes to cost reduction.

  The present invention can be used for a power conversion device having both downsizing and cost reduction, and can also be used for a power conversion device used in an environment where vibration and temperature change are severe such as in-vehicle use.

It is a top view explaining the power module part of the vehicle-mounted power converter device which concerns on Embodiment 1 of this invention. It is a top view which shows the state which attached the power module drive board | substrate to the power module part shown in FIG. It is sectional drawing from the arrow A direction of FIG. 6 is a plan view showing an in-vehicle power converter according to Embodiment 2. FIG. 6 is a plan view of a current sensor according to Embodiment 3. FIG. It is sectional drawing from the arrow B direction of FIG. It is sectional drawing from the arrow C direction of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power module 1a-1c Switching element 2,53 Case 3 DC side terminal 4 AC side terminal 5,6 Bus bar 7, 8, 13, 54 screw 9 Holder 10 Iron core 11a-11c Signal terminal 12 Power module drive board 14a-14f, 40, 51a to 51f Slits 15a to 15f First semiconductor elements 16a to 16c Second semiconductor elements 17a to 17c, 50 Current sensor substrate 18 Hall element 40a First slit 40b Second slits 52a to 52c Semiconductor element 55 Lead

Claims (4)

A power converter for driving an AC power load from a DC power source,
A power module connected between the DC power source and the AC power load;
A power module driving board on which the first semiconductor element for driving the power module is mounted;
A current sensor for detecting the current of the power module,
A power conversion device, wherein a second semiconductor element constituting a circuit of the current sensor is mounted on the power module drive board.   The power converter according to claim 1, wherein a plurality of slits are formed in the power module drive substrate, and the second semiconductor element is mounted between the slits.   3. The electric power according to claim 2, wherein the slit is composed of a first slit from one side of the power module drive substrate toward the center and a second slit that intersects the first slit. Conversion device. A plurality of current sensors are configured in an integrated shape, and a substrate on which a semiconductor element that configures the current sensor circuit is mounted is provided.
A current sensor, wherein a plurality of slits are formed in the substrate, and the semiconductor element is mounted between the slits.

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