JPH07285344A - Structure for motor control circuit of electric vehicle - Google Patents

Abstract

PURPOSE:To improve radiation efficiency, suppress the heating of elements, miniaturize radiating plates, and reduce the cost by bringing a coolant into direct contact with the radiating plate portions of switching elements fixed to the metal radiating plates for cooling. CONSTITUTION:An inlet 8 and an outlet 9 of a coolant are provided on a radiating board 1 fixed with multiple switching elements 2 with screws and formed with a coolant passage 10 inside, and the coolant is circulated by an external pump. The coolant passage 10 of the radiating board 1 is opened at the portions corresponding to the radiating plates 11 of the switching elements 2, and the surrounding of the hole is sealed via an O-ring 5 not to generate a leak. The coolant is brought into direct contact with the radiating plates 11 of the switching elements 2, and the heat of the switching elements 2 is radiated to the coolant via the radiating plates 11. Extremely excellent cooling efficiency is attained, and the radiating plates 11 can be miniaturized and made lightweight.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a control circuit for an electric motor of an electric vehicle which radiates heat from a switching element by liquid cooling.

[0002]

2. Description of the Related Art In recent years, due to the development of switching elements, MOS-F has been used as a switching control circuit for general industrial motors.
ET and IGBT have come to be used. In addition, various types have been developed that can handle large currents. Similar elements are used in switching control circuits for electric vehicles to improve efficiency. However, if the current is large, the amount of heat generated increases due to the switching loss of the element and other factors, and the problem is how to dissipate the heat. As a cooling method, a fan may be provided for forced air cooling, or liquid cooling using water, oil, or the like may be used, but liquid cooling is generally used for downsizing.

A conventional liquid cooling control circuit is shown in FIGS.
First, in FIGS. 3 to 6, the switching element 2 is the heat sink 1.
It is installed on the heat sink 21. The heat radiating plate 1 and the heat radiating plate 21 are provided with liquid passages inside, and by flowing a cooling liquid through them, the heat radiating plate 1 and the heat radiating plate 21 are cooled, and further, the switching element 2 is cooled and the terminal 3 is switched. It is connected to the element 2. The power distribution metal bar 4 is connected to the switching element 2. The heat dissipation plate 7 of the switching element is sandwiched between the switching element 2, the heat dissipation plate 1 and the heat dissipation plate 21.

In FIG. 4, a cooling pipe 6 through which a cooling liquid flows is provided as compared with FIG. 6, and a cooling liquid inlet 8 and a cooling liquid outlet 9 are provided.
Is provided. This cooling pipe 6 cools the radiator plate 1 and the radiator plate 21, and further cools the switching element 2. In either case, since heat resistance exists between the switching element 2 and the heat sink 1 or the heat sink 21, and between the heat sink 1 or the heat sink 21 and the cooling pipe 6, the heat dissipation efficiency is reduced.

[0005]

In order to save energy, the large current control circuit must pursue further improvement in efficiency. Especially when used in electric vehicles and the like, it is essential to improve efficiency in order to extend the cruising range with a limited battery capacity. The loss due to the energization of the switching element leads to an increase in the temperature of the element, which leads to deterioration of the performance of the switching element and further damage. Therefore, it is necessary to use a switching element having a higher rank in order to provide a margin for durability of the switching element, resulting in an increase in size and a significant cost increase.

The present invention solves the above-mentioned problems, and prevents performance deterioration of a switching element by maximizing heat dissipation efficiency with a simple structure, improves reliability, and is small-sized, lightweight and low-cost controller. Is intended to provide.

[0007]

In order to achieve the above-mentioned object, the present invention reduces the thermal resistance between the heat sink and the heat sink of the switching element by directly contacting the cooling solution with the heat sink of the switching element, The heat dissipation efficiency can be maximized.

[0008]

According to the present invention, the heat generation of the switching element is directly transmitted from the heat radiation plate of the switching element to the cooling liquid by the above-described structure, so that the heat radiation efficiency is maximized, the heat generation of the element is suppressed and the heat radiation plate can be downsized, and the control circuit is low cost. Can be provided.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.
Will be described with reference to.

FIG. 1 is an external view of a structural embodiment of a control circuit according to the present invention, and FIG. 2 is a sectional view taken along line AA '. The radiator plate 1 has an inlet 8 and an outlet 9 for the cooling liquid, which are connected by a pipe or the like, and when operating, the cooling liquid is sent by an external pump, passes through the inside of the radiator plate, and is discharged from the opposite side. Switching element 2
Is fixed to the heat sink 1 with screws or the like. The cooling water passage 10 of the heat radiating plate 1 has a hole in the heat radiating plate portion of the switching element 2, and an O-ring 5 or the like is provided around the hole to seal the cooling liquid so as not to leak. Therefore, the cooling liquid comes into direct contact with the heat dissipation plate 11 of the switching element. The heat generated by the operation of the switching element 2 is transferred to the heat dissipation plate 11 of the switching element and further directly transferred to the cooling liquid. In the present invention, the cooling liquid is in direct contact with the heat dissipation plate 11 of the switching element, so that the cooling efficiency during that period is maximized. Further, the heat dissipation plate 1 itself is sufficient if it has a water channel through which a minimum amount of cooling liquid necessary for cooling flows, and a volume and strength to which the switching element 2 can be fixed.
In addition, since the switching element 2 has improved heat dissipation, the margin for heat generation is increased, reliability is improved, and a small one can be used. Therefore, a control circuit of smaller size, lighter weight, and lower cost can be provided.

[0011]

As is apparent from the above description, according to the present invention, the heat generated by the switching element is directly transmitted from the heat radiation plate of the switching element to the cooling liquid, the heat radiation efficiency is maximized, the heat generation of the element is suppressed, and the heat radiation plate is downsized. Therefore, a low-cost control circuit can be provided.

[Brief description of drawings]

FIG. 1 is a plan view of a control circuit according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line AA ′ of the control circuit in FIG.

FIG. 3 is a plan view of a conventional control circuit.

4 is a cross-sectional view taken along the line BB ′ of the control circuit in FIG.

FIG. 5 is a plan view of another conventional control circuit.

6 is a sectional view taken along line CC ′ of the control circuit in FIG.

[Explanation of symbols]

 1, 21 Heat sink 2 Switching element 3 Terminal 4 Distribution metal bar 5 O-ring 6 Cooling pipe 7 Switching element heat sink 8 Coolant inlet 9 Coolant outlet 10 Coolant water channel 11 Switching element drive circuit

Claims (1)

[Claims] 1. A structure of a control circuit for an electric motor of an electric vehicle, wherein a cooling liquid is in direct contact with a heat radiation plate portion of a switching element fixed to a metal heat radiation plate for liquid cooling.