Patent Abstract:
An inverter for an electric vehicle is provided. The inverter for an electric vehicle, which controls an RPM of a motor for the electric vehicle, the inverter including a busbar connected to a power semiconductor module for supplying current, a current sensor measuring the current passing through the busbar, and a control board on which the current sensor is mounted, the control board controlling the motor for the electric vehicle according to a result measured by the current sensor. The busbar is disposed to vertically pass through the current sensor and control board.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Pursuant to 35 U.S.C. §119(a), this application claims the benefit of earlier filing date and right of priority to Korean Patent Application No. 10-2013-0150236, filed on Dec. 4, 2013, the contents of which are hereby incorporated by reference herein in its entirety. 
     BACKGROUND 
     The present disclosure relates to an inverter for an electric vehicle. 
     In recent years, technologies in regard to electrical vehicles traveling by using electricity that is green energy are being rapidly developed. Electric vehicles represent vehicles driven by using electricity. Electric vehicles may be largely classified into battery powered electric vehicles and hybrid electric vehicles. Here, the battery powered electric vehicles represent vehicles driven by using only electricity and thus are generally called electric vehicles. Also, the hybrid electric vehicles represent vehicles driven by using electricity and fossil fuels. 
     Most of electric vehicles include a motor generating a rotation force, a battery supplying power into the motor, an inverter controlling an RPM of the motor, a battery charger charging the battery with electricity, and a low voltage DC/DC converter for electric vehicles. 
     Among these, the inverter includes a sensor for sensing current to precisely control the motor. 
       FIG. 1  is a view of an inverter for an electric vehicle according to the related art. 
     Referring to  FIG. 1 , the electric vehicle according to the related art includes a hole-type current sensor  10 . The current sensor  10  is fitted into a busbar  40  and then mounted on a CT terminal block  60 . 
     According to the inverter for the electric vehicle, current generated from a power semiconductor module  30  is transmitted to the outside through the busbar  40 . Here, the current sensor  10  surrounding the busbar  40  measures the current flowing in the busbar  40  to transfer the measured current to a printed circuit board (PCB)  20  through a wire harness  50 . 
     Here, the CT terminal block  60 , which is a separate fixing unit, is installed to fix the busbar  40 . The current sensor  10  is fitted into a plate-shaped portion of the busbar  40 , and then the current sensor  10  and the busbar  40  are assembled with the CT terminal block  60 . 
     Thus, a separate wire harness  50  is needed to transmit the current from the current sensor  10  to the PCB  20 . 
     In this structure in which the busbar  40  is disposed at a side of the power semiconductor module  30 , the CT terminal block  60  is needed to fix the busbar  40 . Thus, the inverter increases in volume and manufacturing cost. 
     Also, since the busbar  40  have a small section-area to pass through the current sensor  10 , a material of the busbar  40  is limited to copper (Cu). Thus, it is difficult to reduce manufacturing costs of the inverter. 
     SUMMARY 
     Embodiments provide an inverter for an electric vehicle, in which a CT terminal block is removed to reduce a volume and manufacturing costs. 
     In one embodiment, an inverter for an electric vehicle, which controls an RPM of a motor for the electric vehicle, the inverter including: a busbar connected to a power semiconductor module for supplying current; a current sensor measuring the current passing through the busbar; and a control board on which the current sensor is mounted, the control board controlling the motor for the electric vehicle according to a result measured by the current sensor, wherein the busbar is disposed to vertically pass through the current sensor and control board. 
     The busbar may include: a main body having a cylindrical shape; and a fixing part disposed on a lower end of the main body to protrude outward from the main body, wherein the busbar may be coupled to the power semiconductor module through the fixing part. 
     The busbar may be disposed on an upper portion of the power semiconductor module to overlap the power semiconductor module when viewed from above. 
     The current sensor may have a through hole through which the busbar vertically passes. 
     The current sensor may be coupled to a bottom surface of the control board by soldering. 
     The current sensor may include a signal terminal and fixing terminal that are connected to the control board, and wherein the signal and fixing terminals may be coupled to the control board by soldering. 
     The busbar may be formed of an aluminum material. 
     The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view illustrating a portion of an inverter for an electric vehicle according to a related art. 
         FIG. 2  is a side view illustrating a portion of an inverter for an electric vehicle according to an embodiment. 
         FIG. 3  is a perspective view illustrating a portion of the inverter for the electric vehicle according to an embodiment. 
         FIG. 4  is a side view illustrating a portion of the inverter for the electric vehicle according to an embodiment. 
         FIG. 5  is a view of a current sensor. 
         FIG. 6  is a view of a busbar. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, an inverter for an electric vehicle according to an embodiment will be described with reference to the accompanying drawings. 
     An electric vehicle inverter according to an embodiment includes a heatsink  100 , a power semiconductor module  200  coupled to an upper portion of the heatsink  100 , a driving board  300  connected to the power semiconductor module  200 , a busbar  400  having one end connected to the driving board  300 , a current sensor  500  disposed at the outside of the busbar  400 , and a control board  600  connected to the current sensor  500 . 
     The heatsink  100  may exhaust heat generated from the power semiconductor module  200  and be formed of a material having excellent thermal conductivity. 
     The power semiconductor module  200  may include transistors of which an on/off operation is controlled by an external signal, diodes having rectifying property, and other devices. Here, a common transistor may include a metal-oxide semiconductor field-effect-transistor (MOSFET) and an insulated gate bipolar transistor (IGBT). The power semiconductor module  200  is fixed to the upper portion of the heatsink  100 . A bottom surface of the power semiconductor module  200  may be in surface-contact with a top surface of the heatsink  100 . 
     The driving board  300  includes a driving printed circuit board (PCB) and a semiconductor device mounted on the driving PCB. The driving board  300  controls driving of the inverter. The driving board  300  is fixed to the upper portion of the power semiconductor module  200 . 
     The busbar  400  is formed of a conduct material and coupled to the upper portion of the power semiconductor module  200 . In detail, the busbar  400  is coupled to an area at the outside of a portion where the driving board  300  is disposed on the upper portion of the power semiconductor module  200 . 
     The busbar  400  includes a cylindrical part  410  having an approximately cylindrical shape and a fixing part  420  extending outward from the cylindrical part  410 . 
     The cylindrical part  410  may lengthily extend in a vertical direction. A bolt insertion part  411  may be defined by cutting a portion of an upper end of the cylindrical part  410  so that a bolt is coupled to the upper end of the cylindrical part  410 . 
     The fixing part  420  includes a coupling hole  421  vertically passing therethrough. A bolt  700  may pass through the coupling hole  421 . The bolt  700  may fix the fixing part  420  to the power semiconductor module  200 . 
     Thus, the busbar  400  having the above-described structure may be firmly fixed to the upper portion of the power semiconductor module  200  by the bolt  700  passing through a vertical through hole  431  defined in the fixing part  420  of the power semiconductor module  200 . 
     Here, the cylindrical part  410  of the busbar  400  may be disposed vertically directly above the power semiconductor module  200 . In detail, the cylindrical part  410  may have an upper end that is disposed vertically directly above the power semiconductor module  200 . Thus, when viewed from above, the busbar  400  may overlap the power semiconductor module  200 . That is, when viewed from above, the busbar  400  is disposed inside an outer boundary of the power semiconductor module  200 . 
     For reference, the busbar  400  may connect the power semiconductor module  200  to a motor (not shown) of the electric vehicle to allow a current to flow between the semiconductor module  200  and the motor. Thus, the upper end of the busbar  400  may be connected to the motor and a lower end of the busbar  400  may be connected to the power semiconductor module  200 . 
     The busbar  400  may be formed of an aluminum material. Thus, the inverter of the present disclosure may be reduced in manufacturing costs. 
     The current sensor  500  measures the current flowing in the busbar  400  and has a through hole  520  vertically defined in a central portion thereof. The current sensor  500  may sense the current flowing through the busbar  400  passing through the through hole  520 . Also, the current sensor  500  may transmit the sensed information to the control board  600  that will be described later. 
     The current sensor  500  may further include a facing surface  530  that is facing the control board  600 , and signal and fixing terminals  540  and  550  protruding from the facing surface  530  toward the control board  600 . The facing surface  530  may face upward. 
     The signal terminal  540  and the fixing terminal  550  may protrude from the facing surface  530 . Alternatively, the signal terminal  540  and the fixing terminal  550  may protrude from a side surface of the current sensor  500 , which is disposed at a lateral side of the facing surface  530 . 
     The signal terminal  540  is a portion for transmitting a signal by being connected to the control board  600 . The signal terminal  540  may be coupled to the control board  600  by soldering. A current value sensed by the current sensor  500  is transmitted to a control PCB through the signal terminal  540 . 
     The fixing terminal  550  is a portion that is soldered to firmly fix the control board  600  and the current sensor  500  to each other. The fixing terminal  550  may have a thickness greater than that of the signal terminal  540 . 
     The control board  600  includes the control PCB and a semiconductor device mounted on the control PCB. The control board  600  controls the motor. The current sensor  500  is coupled to a lower portion of the control board  600 . 
     Reference numeral  800  represents another busbar. The busbar  800  may connect the power semiconductor module  200  to the battery (not shown). 
     Since the electric vehicle inverter according to an embodiment has the above-described structure, it is unnecessary to use the CT terminal block. In the structure of the typical inverter in which the busbar  40  is disposed at the side of the power semiconductor module  30 , the driving board, and the control board, other member does not exist between the busbar  40  and the heatsink, and thus the CT terminal block is required so as to completely insulate between the busbar  40  and the heatsink. However, according to an embodiment, since the busbar  400  is disposed at the inside of the power semiconductor module  200  and control board  600 , it is unnecessary to insulate between the busbar  400  and the heatsink  100  and to use the CT terminal block. 
     Also, since the CT terminal block is removed, the inverter may be reduced in volume. 
     Also, since the busbar  400  has a section area wider than that of related art to pass through the current sensor  500 , the busbar  400  may be formed of other metal materials such as aluminum (Al), instead of copper (Cu). Thus, the inverter may be reduced in manufacturing costs and in weight to improve fuel-efficiency. 
     According to the present disclosure, the CT terminal block may be removed to reduce the volume of the inverter and manufacturing costs. 
     Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.

Technology Classification (CPC): 1