Patent Description:
Recently, there is a rapid advance in development of technology of electric vehicles driving using electricity that is green energy. Electric vehicles refer to vehicles operated using electricity, and may be largely classified into a battery powered electric vehicle and a hybrid electric vehicle.

Here, the battery powered electric vehicle travels only using electricity, and is generally referred to as an electric vehicle. The hybrid electric vehicle refers to a vehicle that travels using electricity and fossil fuels.

Most electric vehicles include a motor configured to generate rotational power, a battery configured to supply power to the motor, an inverter configured to control a number of rotations of the motor, a battery charger configured to charge electricity to the battery, and a low-voltage direct current (DC)/DC converter (LDC) for a vehicle.

Among the elements described above, the inverter includes a sensor configured to sense current to precisely control the motor.

A sensor in the related art which is configured to sense current is provided separately from a bus bar. In detail, a bus bar, a current sensor, and a shield are combined with each other to thereby provide at least two configurations. Accordingly, an error may occur when the current sensor measures current flowing through the bus bar.

In addition, as the bus bar, the current sensor, and the shield are combined with each other to thereby provide the at least two configurations, it may be difficult to structurally change a location relationship therebetween.

<CIT> discloses a current sensing unit in which a bus bar, a board and a sensor part are reliably fixed to a housing for the purpose of minimizing effects of vibration and shock.

The document <CIT> discloses a further current sensor according to the state of the art.

Therefore, to obviate those problems, an aspect of the detailed description is to provide a current sensor assembly in which a bus bar, a current sensor, and a shield may be combined with each other as one configuration.

Another aspect of the detailed description is to provide a current sensor assembly in which relative positions and distances between the bus bar, the current sensor, and the shield may be optimized.

The present invention is defined by the appended independent claim, and preferred aspects of the present invention are defined by the appended dependent claims. In the following description, there is provided a current sensor assembly including: a housing; a plurality of shields which are accommodated inside the housing and open toward a top of the housing; a plurality of bus bars to which current with three phases is applied and which are arranged spaced apart from each other to go past the plurality of shields, respectively; and a current sensor unit comprising a printed circuit board and a plurality of current sensors disposed on the printed circuit board to measure the current applied to the plurality of bus bars, wherein the plurality of shields, the plurality of bus bars, and the current sensor unit are configured to be accommodated inside the housing, and the current sensors are spaced apart from the plurality of bus bars and disposed in inner spaces of the plurality of shields.

The current sensor assembly may further include a housing cover arranged at an upper end of the housing to cover the inside of the housing, wherein the housing cover extends in a downward direction to include a support protrusion portion in contact with the printed circuit board.

The plurality of current sensors may be disposed on the printed circuit substrate to be spaced apart from each other, and grooves through which the plurality of shields may pass are provided in the printed circuit board.

The plurality of shields may include: inner side surfaces arranged at an inner side of the housing; and protruding surfaces protruding from both sides of the inner side surfaces, wherein the plurality of bus bars are disposed near the inner side surfaces and pass through the plurality of shields, the plurality of current sensors are spaced apart from the plurality of bus bars and arranged between the protruding surfaces, and the inside of the housing is spaced apart from the plurality of shields to provide a first axis in a direction in which the plurality of bus bars pass over the inner side surfaces of the plurality of shields, a second axis in a direction in which the inner side surfaces of the plurality of shields extend, and a third axis in which the plurality of protruding surfaces extend from both ends of the plurality of shields.

Volumes of the plurality of shields may be estimated according to widths and thicknesses of the plurality of shields and lengths of the protruding surfaces, and included in a range in which linearity in a numerical range, in which the plurality of current sensors measure the current applied to the plurality of bus bars, is ensured within a range of current passing through the plurality of bus bars.

The plurality of shields and the plurality of bus bars may be spaced apart from each other in a direction of the third axis by a first distance to ensure the linearity in the numerical range in which the plurality of bus bars measure the current applied to the plurality of bus bars, within the range of the current passing through the plurality of bus bars.

The plurality of current sensors may be spaced apart from the plurality of bus bars in a direction of the third axis by a second distance to maintain the linearity in the measured current within the range of the current passing through the plurality of bus bars.

The plurality of current sensors may be arranged in correspondence to the plurality of the bus bars providing the three phases, respectively, and arranged adjacent to centers between the protruding surfaces of the plurality of shields surrounding of the plurality of current sensors, respectively.

The plurality of current sensors may be arranged spaced apart from surfaces of the inner side surfaces of the plurality of shields in a direction of the third axis by a third distance.

The plurality of current sensors may be disposed spaced apart from centers of the plurality of bus bars in a direction of the second axis by a fourth distance.

The plurality of current sensors may be disposed spaced apart from surfaces of the plurality of bus bars in a direction of the third axis by a constant distance.

In accordance with the detailed description, effects of the present disclosure described herein may be obtained.

Since a support protrusion portion of a housing cover is in contact with a printed circuit board, vibration of a current sensor in a current sensor unit, which may be caused by vibration of a current sensor assembly when an inverter vibrates according to driving of the inverter, may be reduced. Thus, an error that may be caused by the vibration of the current sensor during detection of current supplied to a bus bar may be reduced.

An optimum volume of the shield such that the current sensor may linearly measure current flowing through the bus bar may be easily determined. Further, a range in which the current sensor may linearly measure current according to a position relationship between the bus bar and a current sensor center portion may be easily determined, and thus, positions of the bus bar and the current sensor may be optimized.

Current flowing through the bus bar may be accurately detected by easily determining a position of the current sensor for minimizing a crosstalk effect generated by an adjacent bus bar and adjusting positions of the current sensor and the shield, by measuring and taking into account respective crosstalk effects of the current sensor positioned inside protruding surfaces of the shield with respect to first to third axes.

The current sensor may be arranged near the bus bar by taking into account a change in a magnetic flux density according to a skin effect of the bus bar, and as the current sensor is arranged near an end portion of the bus bar, a phase delay effect that may be caused by a magnetic flux density difference may be reduced.

A mold unit is not arranged to excessively surround the protruding surfaces, and a large portion of the protruding surfaces is exposed from the mold unit. Accordingly, an inner width w between the protruding surfaces is maintained, and thus, a volume of the shield and a shielding ability of the shield may be maintained to be constant.

Description will now be given in detail according to exemplary embodiments disclosed herein, with reference to the accompanying drawings. For the sake of brief description with reference to the drawings, the same or equivalent components may be provided with the same or similar reference numbers, and description thereof will not be repeated. In general, a suffix such as "module" and "unit" may be used to refer to elements or components. Use of such a suffix herein is merely intended to facilitate description of the specification, and the suffix itself is not intended to give any special meaning or function. In describing the present disclosure, if a detailed explanation for a related known function or construction is considered to unnecessarily divert the gist of the present disclosure, such explanation has been omitted but would be understood by those skilled in the art. The accompanying drawings are used to help easily understand the technical idea of the present disclosure and it should be understood that the idea of the present disclosure is not limited by the accompanying drawings. The idea of the present disclosure should be construed to extend to any alterations, equivalents and substitutes besides the accompanying drawings.

It will be understood that when an element is referred to as being "connected with" another element, the element can be connected with the another element or intervening elements may also be present. In contrast, when an element is referred to as being "directly connected with" another element, there are no intervening elements present.

<FIG> is a diagram illustrating an integrated power equipment. <FIG> is a diagram illustrating an inverter assembly. <FIG> is an exploded perspective view illustrating the inverter assembly <NUM> of <FIG>. <FIG> and <FIG> are diagrams for explaining a direction in which current C1 flows in the inverter assembly <NUM>.

Referring to <FIG>, an integrated power device <NUM> is illustrated. The integrated power device <NUM> may include an auxiliary power module (APM) assembly, a charging module, the inverter assembly <NUM>, and a battery disconnect unit (BDU) assembly configured to distribute power to each module. The integrated power device <NUM> is surrounded by a top cover assembly and an integrated module housing.

Referring to <FIG> and <FIG>, the inverter assembly <NUM> included in the integrated power device <NUM> is illustrated. The inverter assembly <NUM> is configured to control current supplied to a motor, and may include a bulk capacitor <NUM> configured to store energy (power) for driving an inverter, a direct current bus bar assembly <NUM>, a control board <NUM>, a gate board <NUM>, a top compressor <NUM>, a power module assembly <NUM>, and a bottom compressor <NUM>.

In addition, current C1 supplied from the bulk capacitor <NUM> to the motor may be delivered to a bus bar <NUM> via a power semiconductor module B. In this process, the current C1 flowing through the bus bar <NUM> may pass through a current sensor assembly A.

<FIG> is a diagram illustrating the current sensor assembly A according to an embodiment of the present invention. <FIG> and <FIG> are exploded perspective views illustrating the current sensor assembly A of <FIG>. <FIG> is a diagram for explaining that a housing cover <NUM> coupled to a rear surface of a housing <NUM> and a support protrusion portion <NUM> protruding from the housing cover <NUM> support a printed circuit board <NUM>. <FIG> is a cross-sectional view for explaining the current sensor assembly A of <FIG>.

Referring to <FIG>, the current sensor assembly A according to an embodiment of the present invention is arranged in a process in which current flows from the bulk capacitor <NUM> configured to store energy (power) for driving an inverter to an assembly <NUM> of the bus bar <NUM>. The bulk capacitor <NUM>, the current sensor assembly A, and the assembly <NUM> of the bus bar <NUM> may be arranged to be coupled to a housing H.

Referring to <FIG>, the current sensor assembly A according to an embodiment of the present invention includes the housing <NUM>, a shield <NUM>, the bus bar <NUM>, and a current sensor unit <NUM>.

The housing <NUM> has an approximate rectangular cross section. An inner space <NUM> in which the shield <NUM>, the bus bar <NUM>, and the current sensor unit <NUM> are accommodated is provided in the housing <NUM>. The shield <NUM>, the bus bar <NUM>, and the current sensor unit <NUM> may be sequentially accommodated in the inner space <NUM> in an upward direction.

The housing <NUM> may further include the housing cover <NUM>. The housing cover <NUM> may be coupled to an upper end of the housing <NUM> to cover the inner space <NUM> of the housing <NUM>.

In detail, a housing groove <NUM> may be provided in a rear surface of the housing <NUM>. In addition, the housing cover <NUM> may extend in a downward direction from a main body of the housing cover <NUM>, and may include a fixing projection portion <NUM> provided to fit into the housing groove <NUM>. As illustrated in <FIG>, when the housing cover <NUM> is arranged to cover the inner space <NUM> of the housing <NUM>, the fixing projection portion <NUM> of the housing cover <NUM> may be connected to the housing groove <NUM> to engage the housing <NUM> with the housing cover <NUM>.

The housing cover <NUM> may extend in a downward direction to include the support protrusion portion <NUM> in contact with the printed circuit board <NUM>.

In detail, as illustrated in <FIG>, the support protrusion unit <NUM> protrudes in a downward direction from the main body of the housing cover <NUM>. In addition, as illustrated in <FIG>, when the housing cover <NUM> is coupled to the housing <NUM>, the support protrusion portion <NUM> may be in contact with the printed circuit board <NUM>.

To do so, the support protrusion portion <NUM> may be provided to have a length slightly greater than a distance h1 between an inner side of the main body of the housing cover <NUM> and the printed circuit substrate <NUM>. For example, the support protrusion portion <NUM> may be provided to be about <NUM> longer than the distance h1 between the inner side of the main body of the housing cover <NUM> and the printed circuit substrate <NUM>.

Since the support protrusion portion <NUM> supports the printed circuit board <NUM>, vibration of the current sensor <NUM> in the current sensor unit <NUM>, which may be caused by vibration of the current sensor assembly A when the inverter vibrates according to driving of the inverter, may be reduced. Thus, an error that may be generated due to the vibration of the current sensor <NUM> during measurement of current supplied to the bus bar <NUM> may be reduced.

A plurality of shields <NUM> are provided. The shields <NUM> is accommodated in the housing <NUM>, and arranged to open toward a top of the housing <NUM>.

The shields <NUM> include inner side surfaces <NUM> arranged inside the housing <NUM> and protruding surfaces <NUM> protruding from both sides of the inner side surfaces <NUM>. In this case, open portions of the shields <NUM> which are not surrounded by three surfaces of the shields <NUM> are arranged toward the top of the housing <NUM>. However, an installation direction of the housing <NUM> may vary according to a design.

Inner portions of the shields <NUM> refer to regions surrounded by the inner side surfaces <NUM> and the protruding surfaces <NUM> of the shields <NUM>. In addition, each of the regions provided by the inner portions of the shields <NUM> may be understood as a volume of each of the shields <NUM>. The volume of each of the shields <NUM> is relevant to a magnitude of current measured by the current sensor <NUM> arranged in each of the shields <NUM>. This will be described later in detail. The bus bar <NUM> is arranged to pass through inside of each of the shields <NUM>.

A plurality of bus bars <NUM> are provided. Three-phase current is applied to each of the bas bars <NUM>. The bus bars <NUM> are arranged near the inner side surfaces <NUM> and spaced apart from each other to pass through the shields <NUM>, respectively.

In detail, as illustrated in <FIG>, first to third bus bars 300a to 300c may be arranged. Currents with different phase may flow to the bus bars <NUM>, respectively. For example, U-phase current may flow to the first bus bar 300a, V-phase current may flow to the second bus bar 300b, and W-phase current may flow to the third bus bar 300c.

In detail, a power module including the bulk capacitor <NUM> may provide three-phase power by supplying three phase currents to drive the motor.

The three-phase power includes three symmetrical sine waves having different phases by an electrical angle of <NUM> degrees, respectively. For example, in a symmetrical three-phase power supply system, three conductors deliver alternate current with a same frequency and a same voltage amplitude but with a phase difference by <NUM>/<NUM> of a cycle, with reference to a common reference. Due to the phase difference, a voltage on an arbitrary conductor reaches a peak after <NUM>/<NUM> of a cycle of another conductor and before <NUM>/<NUM> of a cycle of the other conductor. Such phase delay provides constant power to a balanced linear load. In addition, a rotating magnetic field may be generated in an electric motor and another phase array may be generated using a transformer.

The current sensor unit <NUM> may include the printed circuit board <NUM> and a plurality of current sensors <NUM>.

The plurality of current sensors <NUM> are arranged on the printed circuit board <NUM>. The current sensors <NUM> measure current flowing through the bus bars <NUM>. According to a type of the current sensors <NUM>, a magnitude of current that may be measured may vary. For example, the current sensors <NUM> that may measure a magnetic flux density of <NUM> mT may be used, or a magnetic flux density equal to or greater than <NUM> mT or a magnetic flux density less than <NUM> mT may be measured.

The current sensors <NUM> are spaced apart from the bus bars <NUM> and arranged in the inner spaces <NUM> of the housing <NUM>. The current sensors <NUM> are arranged between the protruding surfaces <NUM> of the shields <NUM>. In detail, referring to <FIG>, the shields <NUM> are inserted into the housing <NUM>. In addition, the bus bars <NUM> are arranged to pass over the shields <NUM>. In addition, the current sensor unit <NUM> is arranged to be apart from the bus bars <NUM> by a certain distance. In this case, the current sensors <NUM> are arranged in regions surrounded by three surfaces of the shields <NUM>.

The plurality of current sensors <NUM> are arranged to be apart from each other on the printed circuit board <NUM>.

Grooves through which the shields <NUM> may pass may be provided in the printed circuit board <NUM>. In detail, as illustrated in <FIG>, first grooves <NUM> through which the shields <NUM> may pass may be provided in the printed circuit board <NUM>.

In addition, second holes <NUM> into which fixing protrusion portions <NUM> protruding from the housing cover <NUM> are inserted may be provided in the printed circuit board <NUM>. The printed circuit board <NUM> may be fixed to the inner space <NUM> of the housing <NUM> by using the fixing protrusion portions <NUM>. In addition, a mold unit md may be provided in the inner space <NUM> of the housing <NUM> to fix the housing <NUM>, the shields <NUM>, and the bus bars <NUM>.

In the current sensor assembly A, the shields <NUM>, the of bus bars <NUM>, and the current sensor unit <NUM> are stacked and fixed in one housing <NUM>. Thus, an error that may occur when the current sensor assembly A is divided into two or more configurations may be reduced. In addition, a design may be performed such that the shields <NUM>, the bus bars <NUM>, and the current sensor unit <NUM> are arranged close to each other in the inner space <NUM> of one housing <NUM> to minimize various problems that may occur when the current sensors <NUM> measure current.

<FIG> and <FIG> are diagrams for explaining a range of current that may be measured by the current sensors <NUM> according to locations of the bus bars <NUM> and the current sensors <NUM> and volumes of the shields <NUM>.

A volume of a shield <NUM> may be provided within a range in which a linearity in a numerical range, in which current supplied to the bus bar <NUM> is measured by the current sensor <NUM>, may be ensured within a range of current passing through the bas bar <NUM>. Thus, the volume of the shield <NUM> may be selected within a magnetic range in which the current sensor <NUM> may measure current.

The volume of the shield <NUM> is estimated by a width w and a thickness t of the shield <NUM> and a length h of the protruding surfaces <NUM>. In detail, referring to (c) of <FIG>, a product of the width w, length l, and height h-t of the shield <NUM> may be the volume of the shield <NUM>.

Referring to (a) of <FIG>, a vertical axis of the table indicates a magnetic flux density measured by the current sensor <NUM> according to volumes of the shields <NUM>. In detail, lines a to d each indicate a magnetic flux density measured by the current sensors <NUM>, according to lengths of inner widths of the shields <NUM> having a same thickness t of the shields <NUM> and a same height of the protruding surfaces <NUM>. In addition, a horizontal axis of the table indicates current supplied to the bus bars <NUM>.

For example, the line a indicates a case when the inner width of the shield <NUM> is about <NUM>, the line b indicates a case when the inner width of the shield <NUM> is about <NUM>, the line c indicates a case when the inner width of the shield <NUM> is about <NUM>, and the line d indicates a case when the inner width of the shield <NUM> is about <NUM>.

Lines e to f indicate magnitudes of magnetic flux densities measured at inner surfaces of the shield <NUM> when lengths of the inner side surfaces <NUM> of the shield <NUM> are about <NUM>, <NUM>, <NUM>, and <NUM>, respectively. When about <NUM> A is exceeded, in all of the four cases described above, the magnetic flux density drastically decreases.

According sizes and performance of the current sensors <NUM>, the current sensors <NUM> may have a maximum magnetic density needed to linearly measure the current supplied to the bus bars <NUM>. For example, in a case of the current sensors <NUM> with a product name of MLX91208CAV, when the current supplied to the bus bars <NUM> is about <NUM> A, the maximum magnetic density may be about <NUM> mT to about <NUM> mT according to lengths of the inner widths of the shields <NUM> measured by the current sensors <NUM>.

The current sensors <NUM> described above may linearly measure a magnetic flux density of up to about <NUM> mT. Accordingly, the lengths of the inner side surfaces <NUM> of the shields <NUM> may be desirably about <NUM> or about <NUM>. In addition, the volumes of the shields <NUM> may be selected within a range in which the current sensors <NUM> may linearly measure the current supplied to the bus bar <NUM>. In this example, the lines c and d may be selected.

First to third axes inside the housing <NUM> may be defined as follows.

The first axis is in a direction in which the bus bars <NUM> are spaced apart from the shields <NUM> and pass over the inner side surfaces <NUM> of the shields <NUM>. For example. referring to (e) of <FIG>, the first axis is in a direction of an x-axis. The second axis is in a direction in which the inner side surfaces <NUM> of the shields <NUM> extend. Referring to (e) of <FIG>, the second axis is in a direction of a y-axis. The third axis is in a direction in which the protruding surfaces <NUM> at both ends of the shields <NUM> extend. Referring to (a) of <FIG>, the third axis is in a direction of a z-axis.

The shields <NUM> and the bus bars <NUM> may be spaced apart from each other in a direction of the third axis by a first distance to ensure linearity in a numerical range in which current supplied to the bus bars <NUM> is measured by the current sensors <NUM>, within a range of current passing through the bas bars <NUM>. In detail, referring to (b) of <FIG>, a distance from inner surfaces of the shields <NUM> to the bus bars <NUM> may be referred to as a first distance in the direction of the third axis. This will be described later in detail with reference to <FIG> and <FIG>.

In addition, the current sensors <NUM> are spaced apart from the bus bars <NUM> by a second distance in the direction of the third axis to maintain linearity of measured current within a range of the current passing through the bus bars <NUM>. In detail, in (b) <FIG>, a distance c from surfaces of the bus bars <NUM> to current sensor center portions <NUM> may be understood as the second distance in the direction of the third axis.

<FIG> illustrates an amount of current measured by the current sensors <NUM> according to changes in relative positions of the bus bars <NUM> and the current sensor center portions <NUM> along the first to third axes.

(a) of <FIG> illustrates magnetic flux densities measured by the current sensor <NUM> in respective positions with reference to the first position 415a on the bus bar <NUM> along the first axis (the x-axis) when the current sensor center portion <NUM> is located in the respective different positions.

When the current sensor <NUM> is located in the first position 415a, a second position 415b, and a third position 415c, magnetic flux densities measured by the current sensor <NUM> in the first to third positions 415a to 415c correspond to lines a to c, respectively. In this case, there is very little difference between the magnetic flux densities measured by the current sensor <NUM> in the first position 415a, the second position 415b, and the third position 415c, respectively.

(b) of <FIG> illustrates magnetic flux densities measured by the current sensor <NUM> in respective positions with reference to the first position 415a on the bus bar <NUM> along the second axis (the y-axis) when the current sensor center portion <NUM> is located in the respective different positions. In this case, there is very little difference between the magnetic flux densities measured by the current sensor <NUM> in the first position 415a, the second position 415b, and the third position 415c, respectively.

(c) of <FIG> illustrates magnetic flux densities measured by the current sensor <NUM> in respective positions with reference to the first position 415a on the bus bar <NUM> along the third axis (the z-axis) when the current sensor center portion <NUM> is located in the respective different positions. The first position 415a is a position of the current sensor center portion <NUM> being spaced apart from the bus bar <NUM> by a reference distance. The second position 415b is a position of the current sensor center portion <NUM> being spaced far apart from the bus bar <NUM>. The third position 415c is a position of the current sensor center portion <NUM> being arranged nearer the bus bar <NUM> than in the first position 415a.

In a case when the current sensor center portion <NUM> is located in the third position 415c nearer the bus bar <NUM> than in the first position 415a, when current of about <NUM> A flows through the bus bar <NUM>, a magnetic flux density measured by the current sensor <NUM> may exceed <NUM> mT. This is because a magnetic field according to the current flowing through the bus bar <NUM> is strong when the current sensor center portion <NUM> is arranged near the bus bar <NUM>. Accordingly, with respect to the magnetic range, it is desirable that the current sensor center portion <NUM> is arranged apart from the bus bar <NUM> by a certain distance rather than being arranged near the bus bar <NUM>.

The current sensor assembly A may easily determine an optimum volume of the shield <NUM> such that the current sensor <NUM> may linearly measure current flowing through the bus bar <NUM>. Further, the current sensor assembly A may easily determine a range in which the current sensor <NUM> may linearly measure current according to a position relationship between the bus bar <NUM> and the current sensor center portion <NUM> to optimize positions of the bus bar <NUM> and the current sensor <NUM>.

<FIG> and <FIG> are diagrams for explaining a crosstalk generated on one current sensor <NUM> according to relative positions of the shield <NUM> and the current sensor <NUM>.

Referring to <FIG>, the bus bar <NUM> may include the first bus bar 300a, the second bus bar 300b, and the third bus bar 300c through which U-phase current, V-phase current, and W-phase current flow, respectively. In this case, the current sensor <NUM> arranged over one bus bar <NUM> such as the first bus bar 300a, the second bus bar 300b, or the third bus bar 300c may measure current flowing through another bus bar <NUM> adjacent to the bus bar <NUM> on which the current sensor <NUM> is arranged. This may be referred to a crosstalk.

To minimize the crosstalk, the plurality of current sensors <NUM> arranged in correspondence to the plurality of the bus bars <NUM> providing the three phases, respectively, may be arranged adjacent to centers between the protruding surfaces <NUM> of the plurality of shield <NUM> surrounding the current sensors <NUM>, respectively.

In detail, (a) of <FIG> illustrates a degree of a crosstalk generated in the current sensor <NUM> in respective positions with reference to the first position 415a between the protruding surfaces <NUM> of the shield <NUM> along the first axis (the x-axis) when the current sensor center portion <NUM> is located in the respective different positions.

Points g1 to g4 indicate a crosstalk effect between the first bus bar 300a and the second bus bar 300b, a crosstalk effect between the first bus bar 300a and the third bus bar 300c, and a crosstalk effect between the second bus bar 300b and the third bus bar 300c, respectively. In addition, crosstalk effects generated in a region a, a region b, and a region c indicate crosstalk effects generated in the first position 415a, the second position 415b, and the third position 415c, respectively.

When the current sensor <NUM> is positioned in the first position 415a, the second position 415b, or the third position 415c between the protruding surfaces <NUM> of the shield <NUM>, respectively, a difference between the crosstalk effects generated in the first to third positions 415a, 415b, and 415c is not significant. A crosstalk effect in the first position 415a that is a reference position is least. Accordingly, a crosstalk effect is least when the current sensor <NUM> is arranged in the first position 415a between the protruding surfaces <NUM> in a direction of the first axis.

(b) of <FIG> illustrates a degree of a crosstalk generated in the current sensor <NUM> in respective positions with reference to the first position 415a between the protruding surfaces <NUM> of the shield <NUM> along the second axis (the y-axis) when the current sensor center portion <NUM> is located in the respective different positions.

A crosstalk effect in the second or third position 415b or 415c is great compared to a cross effect in the first position 415a. Accordingly, the current sensor <NUM> may not measure an accurate current value of the corresponding bus bar <NUM>. Accordingly, a crosstalk effect is least when the current sensor <NUM> is arranged in the first position 415a between the protruding surfaces <NUM> in a direction of the second axis.

(c) of <FIG> illustrates a degree of a crosstalk generated in the current sensor <NUM> in respective positions with reference to the first position 415a between the protruding surfaces <NUM> of the shield <NUM> along the third axis (the z-axis) when the current sensor center portion <NUM> is located in the respective different positions.

It may be understood that a crosstalk effect increases in an order from a case when the current sensor center portion <NUM> is located in the second position 415b, a case when the current sensor center portion <NUM> is located in the first position 415a, to a case when the current sensor center portion <NUM> is located in the third position 415c. This is because a shield effect that may be exerted on the current sensor <NUM> by the protruding surfaces <NUM> is small when the current sensor center portion <NUM> is far apart from the inner side surface <NUM> of the shield <NUM>. Accordingly, an influence exerted on the current sensor <NUM> by current flowing through the adjacent bus bar <NUM> may be great. Accordingly, a crosstalk effect is least when the current sensor <NUM> is arranged in the second position 415b between the protruding surfaces <NUM> in a direction of the third axis.

That is, it may be desirable that the current sensor <NUM> is arranged to be apart from a surface of the inner side surface <NUM> of the shield <NUM> in the third axis by a third distance. In this case, the third distance will be described later in detail with reference to <FIG> and <FIG>.

The current sensor assembly A may measure and take into account respective crosstalk effects with respect to the first to third axes of the current sensor <NUM> positioned in the protruding surfaces <NUM> of the shield <NUM>. By doing so, the current sensor assembly A may accurately measure current flowing through the bus bar <NUM> by easily determining a position of the current sensor <NUM> for minimizing a crosstalk effect generated by the adjacent bus bar <NUM> and adjusting positions of the current sensor <NUM> and the shield <NUM>.

<FIG> and <FIG> are diagrams for explaining a skin effect and phase delay generated according to a frequency of current passing through the bus bar <NUM>.

An upper drawing in <FIG> illustrates a magnetic flux density generated according to each position of the bus bar <NUM> according to a frequency of current flowing through the bus bar <NUM>. Referring to the upper drawing in <FIG>, as a frequency of current increases, a magnetic flux density in a central region <NUM> of the bus bar <NUM> drastically decreases. In addition, as the frequency of current increases, a magnetic flux density in an outer region <NUM> of the bus bar <NUM> greatly increases. This may be referred to a skin effect.

In addition, a lower drawing in <FIG> illustrates phase delay generated in each position of the bus bar <NUM> according to a frequency of current flowing through the bus bar <NUM>. As described above, when a frequency of current increases, a magnetic flux density in the central region <NUM> of the bus bar <NUM> drastically decreases. Accordingly, when the frequency is high, phase delay in the central region <NUM> of the bus bar <NUM> may be greater than that in the outer region <NUM> of the bus bar <NUM>.

To reduce the phase delay described above. the current sensor <NUM> may be arranged apart from a center of the bus bar <NUM> along the second axis by a fourth distance.

In detail, (a) of <FIG> illustrates a degree of phase delay generated for the current sensor <NUM> in respective positions with reference to the first position 415a apart from the bus bar <NUM> along the first axis (the x-axis) when the current sensor center portion <NUM> is located in the respective positions. The regions a to c indicate degrees of phase delay generated in the first position 415a, the second position 415b, and the third position 415c, respectively.

When the current sensor <NUM> moves along the first axis, this indicates that the current sensor <NUM> moves along a central portion of the bus bar <NUM>. Thus, phase delay in the first position 415a, the second position 415b, and the third position 415c are identical to each other. Accordingly, a location of the current sensor <NUM> with reference to the first position 415a along the first axis does not affect phase delay within a certain distance.

(b) of <FIG> illustrates a degree of phase delay generated for the current sensor <NUM> in respective positions with reference to the first position 415a on the bus bar <NUM> along the second axis (the y-axis) when the current sensor center portion <NUM> is located in the respective positions.

In this case, as the current sensor center portion <NUM> moves with reference to the first position 415a along the second axis, the current sensor center portion <NUM> may be moved from the central region <NUM> of the bus bar <NUM> to the outer region <NUM> of the bus bar <NUM>. As described above, a magnetic flux density is high and phase delay occurs little in the outer region <NUM> of the bus bar <NUM>. Thus, occurrence of phase delay may decrease when the current sensor <NUM> moves from the first position 415a that is a reference position, the second position 415b, to the third position 415c.

Accordingly, to reduce a phase delay effect, it may be desirable that the current sensor center portion <NUM>, that is, the current sensor <NUM> moves on the bus bar <NUM> along the second axis.

The current sensor <NUM> may be arranged apart from a surface of the bus bar <NUM> in the third axis by the third distance.

In detail, (c) of <FIG> illustrates a degree of phase delay generated for the current sensor <NUM> in respective positions with reference to the first position 415a on the bus bar <NUM> along the third axis (the z-axis) when the current sensor center portion <NUM> is located in the respective positions.

It may be understood that phase delay decreases as the current sensor <NUM> moves from the first position 415a that is a reference position to the third position 415c arranged near the bus bar <NUM>. In addition, it may be understood that phase delay increases as the current sensor <NUM> moves from the first position 415a to the second position 415b. This is caused by a reduction in phase delay that occurs in the current sensor <NUM> as a magnetic flux density of the bus bar <NUM> increases when the current sensor <NUM> is arranged near the bus bar <NUM>.

Accordingly, it may be understood that the current sensor center portion <NUM> may be desirably moved near the bus bar <NUM> on the bus bar <NUM> along the third axis to reduce a phase delay effect.

However, as described above, when the current sensor <NUM> is arranged too close to the bus bar <NUM>, as a magnetic flux density becomes too high, a magnetic flux density that may be linearly measured by the current sensor <NUM> may be exceeded. Accordingly, it is needed to set a distance for reducing phase delay while a condition for a magnetic flux density that may be measured by the current sensor <NUM> is met.

The current sensor assembly A may be configured such that the current sensor <NUM> is arranged near the bus bar <NUM>, by taking into account a change in the magnetic flux density according to a skin effect of the bus bar <NUM>. As the current sensor <NUM> is arranged near an end portion of the bus bar <NUM>, a phase delay effect caused by a magnetic flux density difference may be reduced.

<FIG> and <FIG> are diagrams for explaining positions of and distances between the shields <NUM>, the bus bars <NUM>, and the current sensor <NUM>.

As described above, the shields <NUM>, the bus bars <NUM>, and the current sensors <NUM> may be spaced apart from each other in a direction of the first, second, or third axis by a certain distance.

In detail, the shields <NUM> and the bus bars <NUM> may be spaced apart from each other in a direction of the third axis by a first distance to ensure linearity of the numerical range in which the current sensors <NUM> measure current supplied to the bus bars <NUM> within a range of current passing through the bas bars <NUM>. Referring to <FIG>, the first distance may be the distance g.

In addition, the current sensors <NUM> may be spaced apart from the bus bars <NUM> in a direction of the third axis by a second direction to maintain linearity of measured current within a range of current passing through the bus bars <NUM>. Referring to <FIG>, the second distance may be the distance c.

That is, the current sensors <NUM> may be arranged apart from a surface of the inner side surface <NUM> of the shields <NUM> in the third axis by a third distance. Referring to <FIG>, the third distance may be a distance obtained by adding the distances g, b, and c.

In addition, to reduce phase delay. the current sensors <NUM> may be arranged apart from centers of the bus bars <NUM> along the second axis by a fourth distance. Referring to <FIG>, the fourth distance may be a distance f (refer to (a) of <FIG>).

When the thickness t of the shield <NUM> is <NUM>, a desirable distance obtained by taking into account all of a magnetic range in which the current sensors <NUM> may measure current, a crosstalk effect, and a phase delay effect is described below.

The inner width w between the protruding surfaces <NUM> of the shields <NUM> may be desirably about <NUM>. The length h of the protruding surfaces <NUM> of the shields <NUM> may be desirably about <NUM>. An inner side distance h' between the shields <NUM> may be desirably about <NUM>.

A horizontal length a of the bus bars <NUM> may be desirably about <NUM>. A thickness b of the bus bars <NUM> may be desirably about <NUM>. A distance between surfaces of the bus bars <NUM> and the current sensor center portion <NUM> may be desirably about <NUM>. A distance i between the surfaces of the bus bars <NUM> and inner side surfaces of the protruding surfaces <NUM> at one side may be desirably about <NUM>. A distance j between a bus bar <NUM> and another bus bar <NUM> adjacent thereto may be desirably about <NUM>. A distance g between surface of the bus bar <NUM> and the inner side surface <NUM> of the shield <NUM> may be desirably about <NUM>.

A distance d between the current sensor center portion <NUM> and an end portion of the protruding surface <NUM> may be desirably about <NUM>. A distance e between the current sensor center portion <NUM> and the inner side surface <NUM> of the protruding surface <NUM> may be desirably about <NUM>. A distance k between the current sensor center portion <NUM> and an end portion of the shield <NUM> may be desirably about <NUM>. The distance f between the current sensor center portion <NUM> and a central portion of the bus bar <NUM> may be desirably about <NUM>.

However, a desirable distance between the respective elements described above may be changed according to a volume of the shield <NUM>, a measurement capability of the current sensor <NUM>, and a magnitude of current supplied and a frequency applied to the bus bar <NUM>.

(b) of <FIG> is a diagram illustrating the bus bar <NUM>.

Referring to (b) of <FIG>, a width of the bus bar <NUM> may be greater than that in the embodiment described above. In detail, the width of the bus bar <NUM> may be small in a section in which the bus bar <NUM> passes through the shield <NUM>. Thus, a magnetic flux density in the bus bar <NUM> may be increased in the section in which the bus bar <NUM> passes through the shield <NUM>.

In detail, in the section the bus bar <NUM> passes through the shield <NUM>, when a width a of the bus bar <NUM> is <NUM>, a width a' of the bus bar <NUM> in sections before and after the bus bar <NUM> passes through the shield <NUM> may be greater than <NUM>, for example,<NUM> to <NUM>. To provide such a section, bus bar protruding portions <NUM> of the bus bar <NUM> may be provided. In addition, a concave portion <NUM>' of the bus bar <NUM> may be provided between the bus bar protruding portions <NUM>.

However, since a phase delay effect decreases in an outer region of the bus bar <NUM>, it may be desirable that the current sensor <NUM> is arranged at an end portion of the bus bar <NUM>.

<FIG> is a diagram for explaining a mold unit md configured to fix the shield <NUM> and the bus bar <NUM> to inside of the housing <NUM>.

The shield <NUM> and the bus bar <NUM> may be fixed inside the housing <NUM> by the mold unit md. In detail, after the shield <NUM> and the bus bar <NUM> are arranged in the inner space <NUM> of the housing <NUM>, the mold unit md may be arranged in the inner space <NUM> of the housing <NUM> to fix positions of the shield <NUM> and the bus bar <NUM>.

However, when the mold unit md is provided to surround a large portion of the protruding surfaces <NUM> of the shield <NUM> as illustrated in (a) of <FIG>, a problem described below may occur. In a process in which the mold unit md in a liquid state coagulates to a solid, force f such as heat expansion or shrinkage may occur. The force f on the mold unit md may be applied to the protruding surfaces <NUM>.

A torque tq that is a bending force may occur on the protruding surfaces <NUM> at both sides of the shield <NUM> according to the force f applied to the protruding surfaces <NUM> by the mold unit md. According to the torque tq, the protruding surfaces <NUM> may become apart from each other or close to each other. Thus, a length of the inner width w between the protruding surfaces <NUM> may vary. When the length of the inner width w between the protruding surfaces <NUM> changes, a whole volume of the shield <NUM> may be changed. Accordingly, a magnetic flux density sensed by the current sensor <NUM> may be affected.

Referring to (b) of <FIG>, the mold unit md may be provided not to cover the protruding surfaces <NUM> of the shield <NUM>. Thus, since the protruding surfaces <NUM> are not affected by heat expansion force or shrinkage force generated as the mold unit md is hardened, the length of the inner width w between the protruding surfaces <NUM> may be maintained to be constant.

In addition, referring to (c) of <FIG>, a height a of the protruding portions <NUM> surrounded by the mold unit md may be provided as being less than <NUM>% of a whole height b of the protruding surfaces <NUM>. Thus, a force provided by the mold unit md to fix the shield <NUM> may be maximized, and at same time, generation of the torque tq on the protruding surfaces <NUM> due to force generated by the hardening of the mold unit md may be reduced.

The current sensor assembly A is provided such that a large portion of the protruding surfaces <NUM> is exposed by the mold unit md, and the mold unit md does not excessively surround the protruding surfaces <NUM>. Accordingly, the inner width w between the protruding surfaces <NUM> is maintained, and thus, the volume of the shield <NUM> and a shielding ability of the shield <NUM> may be maintained to be constant.

Claim 1:
A current sensor assembly comprising:
a housing (<NUM>);
a plurality of shields (<NUM>) which are accommodated inside the housing (<NUM>) and open toward a top of the housing (<NUM>), wherein the plurality of shields (<NUM>) comprise inner side surfaces (<NUM>) arranged at an inner side of the housing (<NUM>), and protruding surfaces (<NUM>) protruding from both sides of the inner side surfaces (<NUM>);
a plurality of bus bars (<NUM>) to which current with three phases is applied and which are arranged spaced apart from each other to extend past the plurality of shields (<NUM>), respectively;
a mold unit (md) moulded inside the housing (<NUM>) and configured to fix positions of the plurality of the shields (<NUM>) and the plurality of the bus bars (<NUM>), wherein the mold unit (md) is arranged not to cover the protruding surfaces (<NUM>) of the shields (<NUM>); and
a current sensor unit (<NUM>) comprising a printed circuit board (<NUM>) and a plurality of current sensors (<NUM>) disposed on the printed circuit board (<NUM>) to measure the current applied to the plurality of bus bars (<NUM>),
wherein the plurality of shields (<NUM>), the plurality of bus bars (<NUM>), and the current sensor unit (<NUM>) are configured to be accommodated inside the housing (<NUM>), and
the current sensors (<NUM>) are spaced apart from the plurality of bus bars (<NUM>) and located between the protruding surfaces (<NUM>) of the plurality of shields (<NUM>).