Semiconductor devices

Abstract

Multiple active components of a semiconductor device are uniformly cooled. The first plurality of active components, the second plurality of active components, and the passive components are respectively arranged in the first range, the second range, and the third range in the first direction. The third range is located between the first range and the second range. The pin fins are accommodated in the opening portion of the cooling jacket. The opening portion has a first outlet and a second outlet at the downstream end portion in the second direction. The first outlet and the second outlet are respectively arranged in the first range and the second range. The cooling jacket has a diverter wall at the downstream end portion in the second direction. The diverter wall is arranged in the third range. The cooling jacket has a refrigerant inlet groove on the bottom surface. The refrigerant inlet groove is arranged in the third range, extending from the upstream end portion in the second direction to the middle of the arrangement range of the first plurality of active components and the second plurality of active components in the second direction.

Description

Technical Field

[0001] The present invention relates to semiconductor devices. Background Art

[0002] The water-cooled power module includes a cooler and a plurality of semiconductor elements. A refrigerant flows through the cooler. The plurality of semiconductor elements are cooled by the refrigerant flowing through the cooler.

[0003] In water-cooled power modules, various cooler structures have been proposed in order to efficiently cool a plurality of semiconductor elements.

[0004] For example, in the technology described in Patent Document 1, a baffle plate is provided to prevent the coolant from bypassing the heat dissipation fin group and flowing (paragraph 0070). This can improve the cooling performance of the power module (paragraph 0070).

[0005] In addition, in the technology described in Patent Document 2, the water cooling jacket is deformed by the convex portion of the central portion of the circuit board (paragraph 0039). As a result, the flow path of the water cooling jacket at the central portion of the circuit board becomes narrower, so the flow rate in this portion becomes faster (paragraph 0039). As a result, the heat dissipation of the power module can be improved (paragraph 0039).

[0006] Patent Document 1: Japanese Patent Application Publication No. 2013-13255

[0007] Patent Document 2: Japanese Patent Application Publication No. 2007-266224 Summary of the invention

[0008] However, in the case of conventional water-cooled power modules, the refrigerant that has become high temperature for cooling the semiconductor elements arranged on the upstream side of the refrigerant flow is used to cool the semiconductor elements arranged on the downstream side of the refrigerant flow. Therefore, the temperature of the semiconductor elements of the latter is higher than that of the semiconductor elements of the former. As a result, the lifespan of multiple semiconductor elements fluctuates. This problem becomes particularly significant when high-load power is applied.

[0009] The present invention has been made in view of these problems. An object of the present invention is to uniformly cool a plurality of active elements included in a semiconductor device.

[0010] The semiconductor device includes a base plate with pin fins, a first plurality of active elements, a second plurality of active elements, a passive element, and a cooling jacket.

[0011] The base plate with pin fins has a base plate and pin fins. The base plate has a first main surface and a second main surface. The second main surface is located on the opposite side to the first main surface.

[0012] A first plurality of active elements, a second plurality of active elements, and passive elements are arranged on the first main surface. A pin fin is connected to the second main surface.

[0013] The first direction and the second direction are parallel to the first main surface, and the second direction is perpendicular to the first direction.

[0014] The first plurality of active elements, the second plurality of active elements and the passive elements are arranged in a first range, a second range and a third range in the first direction, respectively. The third range is located between the first range and the second range. The first plurality of active elements are arranged along the second direction. The second plurality of active elements are arranged along the second direction.

[0015] The cooling jacket has an opening, and the pin fins are housed in the opening.

[0016] In the first aspect of the present invention, the opening portion has a first outlet and a second outlet at the downstream end portion in the second direction. The first outlet and the second outlet are respectively arranged in the first range and the second range. In addition, the cooling jacket has a flow dividing wall at the downstream end portion in the second direction. The flow dividing wall is arranged in the third range, and is arranged between the first outlet and the second outlet.

[0017] In the second aspect of the present invention, the opening has an inlet at the upstream end in the second direction. In addition, the cooling jacket has a bottom surface. The bottom surface is opposite to the second main surface across the opening. In addition, the cooling jacket has a coolant introduction groove on the bottom surface. The coolant introduction groove is arranged in a third range, extending from the upstream end in the second direction to the middle of the arrangement range of the first plurality of active elements and the second plurality of active elements in the second direction.

[0018] Effects of the Invention

[0019] According to the first aspect of the present invention, a refrigerant flow that flows through the downstream portion of the opening in the second direction and flows out from the opening is formed in the first range and the second range in the first direction, and such a refrigerant flow is not formed in the third range in the first direction. Therefore, the flow velocity of the refrigerant flow that flows through the downstream portion of the opening in the second direction becomes faster. Thus, the active components arranged on the downstream side of the second direction can be effectively cooled. Therefore, a plurality of active components of a semiconductor device can be uniformly cooled.

[0020] According to the second aspect of the present invention, when a coolant flow is formed that flows through the downstream portion of the opening and flows out from the opening, the coolant flow formed by the coolant flow flowing through the coolant introduction groove and maintained at a low temperature is merged. Thus, the active element arranged on the downstream side of the second direction can be effectively cooled. Therefore, a plurality of active elements of the semiconductor device can be uniformly cooled.

[0021] The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is an exploded perspective view schematically illustrating the semiconductor device according to the first embodiment.

[0023] Figure 2 This is a plan view schematically showing a semiconductor module included in the semiconductor device according to the first embodiment.

[0024] Figure 3 This is a perspective view schematically showing a cooling jacket and an O-ring included in the semiconductor device according to the first embodiment.

[0025] Figure 4 This is a perspective view schematically showing a portion of a cooling jacket and an O-ring included in the semiconductor device according to the first embodiment.

[0026] Figure 5 This is a plan view schematically showing a portion of a cooling jacket and an O-ring included in the semiconductor device of the first embodiment, and a coolant flow formed inside the semiconductor device of the first embodiment. DETAILED DESCRIPTION

[0027] 1 Implementation Method 1

[0028] 1.1 Semiconductor Devices

[0029] Figure 1 This is an exploded perspective view schematically illustrating the semiconductor device according to the first embodiment.

[0030] Figure 1 The semiconductor device 1 according to the illustrated embodiment 1 is a semiconductor module with a cooling jacket.

[0031] The semiconductor device 1 includes a semiconductor module 11 , a cooling jacket 12 , an O-ring 13 , and screws 14 .

[0032] The semiconductor module 11 has a base plate 101 with pin fins, a first plurality of active elements 102, a second plurality of active elements 103, and a plurality of passive elements 104. In addition, the semiconductor module 11 has a mounting screw hole 111. The base plate 101 with pin fins has a base plate 121 and pin fins 122. The first plurality of active elements 102, the second plurality of active elements 103, and the plurality of passive elements 104 are arranged on a first main surface 121a of the base plate 121. The pin fins 122 are combined with a second main surface 121b of the base plate 121. The second main surface 121b is located on the side opposite to the side where the first main surface 121a is located.

[0033] The cooling jacket 12 has a mounting screw hole 131, an opening 132, and an O-ring groove 133. The mounting screw hole 131, the opening 132, and the O-ring groove 133 are arranged on the mounting surface 12a of the cooling jacket 12. A screw groove is formed on the inner surface of the mounting screw hole 131. The O-ring groove 133 is arranged along the outer periphery of the opening 132. A refrigerant flows in the opening 132.

[0034] The O-ring 13 is accommodated in the O-ring groove 133. The screw 14 passes through the mounting screw hole 111 and is screwed into the mounting screw hole 131. Thus, the semiconductor module 11 is mounted on the mounting surface 12a of the cooling jacket 12 via the O-ring 13. The O-ring 13 blocks the path from the opening 132 through the gap between the semiconductor module 11 and the cooling jacket 12 to the outside of the semiconductor device 1. Thus, the refrigerant flowing through the opening 132 is sealed.

[0035] In a state where the semiconductor module 11 is mounted on the mounting surface 12a of the cooling jacket 12, the pin fins 122 are accommodated in the opening 132. Thus, the pin fins 122 are immersed in the refrigerant flowing through the opening 132. Thus, the heat generated by the first plurality of active elements 102, the second plurality of active elements 103, and the plurality of passive elements 104 is sequentially conducted to the refrigerant flowing through the opening 132 via the base plate 121 and the pin fins 122. The conducted heat is transferred to the outside of the semiconductor device 1 by the refrigerant flow flowing out of the opening 132. Thus, the first plurality of active elements 102, the second plurality of active elements 103, and the plurality of passive elements 104 are cooled by the refrigerant.

[0036] 1.2 Semiconductor Module

[0037] Figure 2 This is a plan view schematically showing a semiconductor module included in the semiconductor device according to the first embodiment.

[0038] Figure 2 The semiconductor module 11 shown in the figure is a 6-in-1 semiconductor module. Therefore, the active element group composed of the first plurality of active elements 102 and the second plurality of active elements 103 includes 6 semiconductor elements for switching. The semiconductor module 11 may also be a semiconductor module other than the 6-in-1 semiconductor module. The semiconductor module 11 is installed in a power conversion device. The power conversion device is an inverter, etc. The semiconductor module 11 may also be installed in a device other than the power conversion device.

[0039] The first plurality of active elements 102, the second plurality of active elements 103, and the plurality of passive elements 104 are bonded to the first main surface 121a of the base plate 121. The bonding longitudinal structure for bonding the first plurality of active elements 102, the second plurality of active elements 103, and the plurality of passive elements 104 to the first main surface 121a of the base plate 121 is not limited.

[0040] The first plurality of active elements 102 include active elements 102U, 102V, and 102W. The second plurality of active elements 103 include active elements 103U, 103V, and 103W. The plurality of passive elements 104 include passive elements 104PU, 104PV, 104PW, 104NU, 104NV, and 104NW.

[0041] Active components 102U, 102V and 102W are respectively switching elements on the upper bridge arm side of the U phase, the V phase and the W phase. Active components 103U, 103V and 103W are respectively switching elements on the lower bridge arm side of the U phase, the V phase and the W phase. The switching element is an insulated gate bipolar transistor (IGBT). The switching element may also be a switching element other than the IGBT. For example, the switching element may be a metal oxide semiconductor field effect transistor (MOSFET). Passive components 104PU, 104PV and 104PW are respectively freewheeling diodes on the upper bridge arm side of the U phase, the V phase and the W phase. Passive components 104NU, 104NV and 104NW are respectively freewheeling diodes on the lower bridge arm side of the U phase, the V phase and the W phase.

[0042] The plurality of passive elements 104 are arranged in the central portion of the first main surface 121a. The first plurality of active elements 102 and the second plurality of active elements 103 are arranged in the peripheral portion of the first main surface 121a. Therefore, the first plurality of active elements 102 are arranged in a first range R1 in the first direction X parallel to the first main surface 121a of the base plate 121. In addition, the second plurality of active elements 103 are arranged in a second range R2 in the first direction X. The plurality of passive elements 104 are arranged in a third range R3 in the first direction X located between the first range R1 and the second range R2.

[0043] The active elements 102U, 102V, and 102W constituting the first plurality of active elements 102 are linearly arranged along a second direction Y that is parallel to the first main surface 121a of the base plate 121 and perpendicular to the first direction X. The active elements 103U, 103V, and 103W constituting the second plurality of active elements 103 are linearly arranged along the second direction Y. The passive elements 104PU, 104PV, and 104PW constituting the plurality of passive elements 104 are linearly arranged along the second direction Y. The passive elements 104NU, 104NV, and 104NW constituting the plurality of passive elements 104 are linearly arranged along the second direction Y.

[0044] The active element 102U, the active element 103U, the passive element 104PU, and the passive element 104NU of the U phase are linearly arranged along the first direction X. The active element 102V, the active element 103V, the passive element 104PV, and the passive element 104NV of the V phase are linearly arranged along the first direction X. The active element 102W, the active element 103W, the passive element 104PW, and the passive element 104NW of the W phase are linearly arranged along the first direction X.

[0045] The refrigerant for cooling the first plurality of active components 102, the second plurality of active components 103 and the plurality of passive components 104 flows along a refrigerant flow direction D from the positions of the active components 102U, 103U, 104PU and 104NU configured with the U phase, through the positions of the active components 102V, 103V, 104PV and 104NV configured with the V phase, toward the positions of the active components 102W, 103W, 104PW and 104NW configured with the W phase.

[0046] 1.3 Cooling Jacket

[0047] Figure 3 This is a perspective view schematically showing a cooling jacket and an O-ring included in the semiconductor device according to the first embodiment. Figure 4 This is a perspective view schematically showing a portion of a cooling jacket and an O-ring included in the semiconductor device according to the first embodiment. Figure 4 The cooling jacket and a portion of the O-ring shown in the figure correspond to the Figure 3 The cooling jacket and O-ring shown will Figure 3 The dotted line portion depicted in FIG.

[0048] Cooling jacket 12 Figure 3 and Figure 4 As shown in the figure, there are an inlet path 141 and an outlet path 142. The opening portion 132 has an inlet 150, a first outlet 151, and a second outlet 152. The inlet path 141 has an inlet 153. The outlet path 142 has an outlet 154. The inlet 153 and the outlet 154 are arranged on the surface of the cooling jacket 12.

[0049] The inflow path 141 and the outflow path 142 extend in the second direction Y. The opening 132 has an inlet 150 at an upstream end in the second direction Y. The opening 132 has a first outlet 151 and a second outlet 152 at a downstream end in the second direction Y.

[0050] The inflow path 141 reaches the inlet 150 from the inflow port 153. The outflow path 142 reaches the outflow port 154 from the first outlet 151 and the second outlet 152. Thus, the refrigerant flowing into the inflow path 141 through the inflow port 153 flows through the inflow path 141 to reach the inlet 150, and flows into the opening 132 through the inlet 150. The refrigerant flowing into the opening 132 flows through the opening 132 to reach the first outlet 151 and the second outlet 152, and flows out of the opening 132 through the first outlet 151 and the second outlet 152. The refrigerant flowing out of the opening 132 flows through the outflow path 142 to reach the outflow port 154, and flows out of the outflow path 142 through the outflow port 154.

[0051] The bottom surface 12b of the cooling jacket 12 is opposite to the second main surface 121b of the base plate 121 via the opening 132. The bottom surface 12b of the cooling jacket 12 is separated from the second main surface 121b of the base plate 121 in the thickness direction of the base plate 121. The cooling jacket 12 has a bottom surface protrusion 161. The bottom surface protrusion 161 has a bottom surface 12b, and the bottom surface 12b is raised to the configuration position of the front end of the pin fin 122.

[0052] The cooling jacket 12 has a coolant introduction groove 171 on the bottom surface 12b. The coolant introduction groove 171 is arranged in a third range R3 in the first direction X. The coolant introduction groove 171 extends from the upstream end of the opening 132 in the second direction Y to the arrangement range R of the first plurality of active elements 102 and the second plurality of active elements 103 in the second direction Y (see Figure 2 ) midway.

[0053] The first outlet 151 is arranged in a first range R1 in the first direction X. The second outlet 152 is arranged in a second range R2 in the first direction X. The cooling jacket 12 has a diverter wall 12c at the downstream end of the opening 132 in the second direction Y. The diverter wall 12c is arranged in a third range R3 in the first direction X. The diverter wall 12c blocks the flow from the bottom surface 12b of the cooling jacket 12 to the second main surface 121b of the base plate 121. The diverter wall 12c is arranged between the first outlet 151 and the second outlet 152 to separate the first outlet 151 and the second outlet 152 from each other.

[0054] 1.4 Refrigerant flow

[0055] Figure 5 This is a plan view schematically showing a portion of a cooling jacket and an O-ring included in the semiconductor device of the first embodiment, and a coolant flow formed inside the semiconductor device of the first embodiment.

[0056] Figure 5The low-temperature refrigerant flow A flowing through the inflow path 141 shown in the figure forms refrigerant flows B1 and B2 flowing through the upstream portion 181 and the midstream portion 182 of the opening portion 132, and forms a refrigerant flow C1 flowing through the refrigerant introduction groove 171. The refrigerant flow B1 is formed in the first range R1 of the first direction X. The refrigerant flow B2 is formed in the second range R2 of the first direction X. The refrigerant flows B1, B2, and C1 travel from the upstream side of the second direction Y to the downstream side of the second direction Y.

[0057] The refrigerant flow C1 flows out from the refrigerant inlet groove 171 at the midstream portion 182 of the opening portion 132, forming refrigerant flows C2, C3 and C4 flowing through the midstream portion 182 of the opening portion 132. The refrigerant flows C2, C3 and C4 are formed in the third range R3 of the first direction X. The refrigerant flow C2 flows from the third range R3 of the first direction X to the first range R1 of the first direction X while traveling from the upstream side of the second direction Y to the downstream side of the second direction Y. The refrigerant flow C3 flows from the third range R3 of the first direction X to the second range R2 of the first direction X while traveling from the upstream side of the second direction Y to the downstream side of the second direction Y. The refrigerant flow C4 travels from the upstream side of the second direction Y to the downstream side of the second direction Y.

[0058] The refrigerant flow C4 hits the diverter wall 12c to form refrigerant flows C5 and C6 that flow through the downstream portion 183 of the opening 132. The refrigerant flows C5 and C6 are formed in the third range R3 of the first direction X. The refrigerant flow C5 travels from the third range R3 of the first direction X to the first range R1 of the first direction X. The refrigerant flow C6 travels from the third range R3 of the first direction X to the second range R2 of the first direction X.

[0059] The refrigerant flows B1, C2, and C5 merge to form a refrigerant flow D1 that flows through the downstream portion 183 of the opening 132 and flows out of the opening 132 through the first outlet 151. The refrigerant flows B2, C3, and C6 merge to form a refrigerant flow D2 that flows through the downstream portion 183 of the opening 132 and flows out of the opening 132 through the second outlet 152. The refrigerant flow D1 is formed in the first range R1 of the first direction X. The refrigerant flow D2 is formed in the second range R2 of the first direction X. The refrigerant flows D1 and D2 travel from the upstream side of the second direction Y to the downstream side of the second direction Y.

[0060] The cooling medium flow B1 flows under the active elements 102U and 102V. The cooling medium flow B1 absorbs the heat generated by the active elements 102U and 102V and becomes a high temperature. The cooling medium flow B2 flows under the active elements 103U and 103V. The cooling medium flow B2 absorbs the heat generated by the active elements 103U and 103V and becomes a high temperature.

[0061] The coolant flow C1 does not flow under the active elements 102U, 102V, 103U, and 103V but flows under the plurality of passive elements 104, and is kept at a low temperature. Therefore, the coolant flows C2, C3, C4, C5, and C6 formed by the coolant flow C1 are kept at a low temperature.

[0062] The cooling medium flow D1 flows under the active element 102W. The cooling medium flow D1 absorbs the heat generated by the active element 102W. The cooling medium flow D2 flows under the active element 103W. The cooling medium flow D2 absorbs the heat generated by the active element 103W.

[0063] According to the invention of embodiment 1, in the first range R1 and the second range R2 of the first direction X, coolant flows D1 and D2 are formed that flow through the downstream portion 183 of the opening 132 along the second direction Y and flow out from the opening 132, and such coolant flows are not formed in the third range R3 of the first direction X. Therefore, the flow rate of the coolant flows D1 and D2 for cooling the active elements 102W and 103W arranged on the downstream side of the second direction Y becomes faster. Thus, the thermal resistance Rth(j_w) of the active elements 102W and 103W arranged on the downstream side of the second direction Y can be reduced, and the active elements 102W and 103W can be effectively cooled. That is, the temperature rise of the active elements 102W and 103W can be alleviated. Therefore, the multiple active elements 102U, 102V, 102W, 103U, 103V and 103W possessed by the semiconductor device 1 can be uniformly cooled.

[0064] In addition, according to the invention of Embodiment 1, when the downstream portion 183 flowing through the opening portion 132 is formed, and the coolant flows D1 and D2 flowing out from the opening portion 132 to cool the active elements 102W and 103W are made to merge, the coolant flows C2, C3, C5, and C6 formed by the coolant flow C1 flowing through the coolant inlet groove 171 and maintained at a low temperature are made to merge. Therefore, the temperature of the coolant flows D1 and D2 for cooling the active elements 102W and 103W arranged on the downstream side of the second direction Y becomes lower. Thus, the active elements 102W and the active elements 103W arranged on the downstream side of the second direction Y can be effectively cooled. Therefore, the plurality of active elements 102U, 102V, 102W, 103U, 103V, and 103W possessed by the semiconductor device 1 can be uniformly cooled.

[0065] Therefore, in the semiconductor device 1 of the first embodiment, the multiple active elements 102U, 102V, 102W, 103U, 103V, and 103W of the semiconductor device 1 can be uniformly cooled by the complementary effect of the flow dividing wall 12c and the coolant introduction groove 171. As a result, the temperature fluctuation of the multiple active elements 102U, 102V, 102W, 103U, 103V, and 103W can be suppressed, and the reliability of the semiconductor device 1 can be improved.

[0066] The refrigerant inlet groove 171 slows down the flow rate of the refrigerant flowing over the refrigerant inlet groove 171. However, the refrigerant flowing over the refrigerant inlet groove 171 flows under the plurality of passive components 104 that do not generate a large amount of heat, and therefore, the slowing down of the flow rate of the refrigerant flowing over the refrigerant inlet groove 171 does not have a significant impact on the cooling of the plurality of active components 102U, 102V, 102W, 103U, 103V, and 103W.

[0067] In addition, the number, position, shape, etc. of the cooling medium introduction grooves 171 may be changed according to the number, position, shape, etc. of the active components and the passive components, and the number, position, shape, etc. of the outlets 151 and 152 may also be changed.

[0068] In addition, the present invention can appropriately modify or omit the embodiments within the scope of the present invention.

[0069] While the present invention has been described in detail, the above description is in all aspects illustrative and the present invention is not limited thereto, and it is understood that numerous modifications not shown here are conceivable without departing from the scope of the present invention.

[0070] Description of the label

[0071] 1 semiconductor device, 11 semiconductor module, 12 cooling jacket, 12b bottom surface, 12c diverter wall, 101 base plate with pin fins, 102 first plurality of active components, 103 second plurality of active components, 104 plurality of passive components, 121 base plate, 122 pin fins, 121a first main surface, 121b second main surface, X first direction, Y second direction, R1 first range, R2 second range, R3 third range, R configuration range, 150 inlet, 151 first outlet, 152 second outlet, 171 refrigerant introduction groove.

Claims

1. A semiconductor device comprising: A base plate with pin fins, comprising a base plate and pin fins, wherein the base plate has a first main surface and a second main surface located on the side opposite to the first main surface, and the pin fins are combined with the second main surface; a first plurality of active elements disposed on the first main surface, disposed in a first range in a first direction parallel to the first main surface, and arranged along a second direction parallel to the first main surface and perpendicular to the first direction; A second plurality of active elements are arranged on the first main surface, in a second range in the first direction, and arranged along the second direction; a passive element disposed on the first main surface and disposed in a third range in the first direction between the first range and the second range; and A cooling jacket having an opening portion for accommodating the pin fins, the opening portion having a first outlet arranged in the first range and a second outlet arranged in the second range at the downstream end portion in the second direction, the cooling jacket having a diverter wall at the downstream end portion in the second direction of the opening portion, the diverter wall being arranged in the third range and between the first outlet and the second outlet.

2. The semiconductor device according to claim 1, wherein The first plurality of active elements are switch elements on the upper arm side of the U phase, the V phase, and the W phase, The second plurality of active elements are switch elements on the lower bridge arm side of the U phase, the V phase and the W phase, The passive elements are freewheeling diodes on the upper arm side and the lower arm side of the U phase, the V phase, and the W phase.

3. A semiconductor device comprising: A base plate with pin fins, comprising a base plate and pin fins, wherein the base plate has a first main surface and a second main surface located on the side opposite to the first main surface, and the pin fins are combined with the second main surface; a first plurality of active elements disposed on the first main surface, disposed in a first range in a first direction parallel to the first main surface, and arranged along a second direction parallel to the first main surface and perpendicular to the first direction; A second plurality of active elements are arranged on the first main surface, in a second range in the first direction, and arranged along the second direction; a passive element disposed on the first main surface and disposed in a third range in the first direction between the first range and the second range; and A cooling jacket having an opening portion for accommodating the pin fins, the opening portion having an inlet at an upstream end portion in the second direction, the cooling jacket having a bottom surface opposite to the second main surface across the opening portion, the cooling jacket having a coolant inlet groove on the bottom surface, the coolant inlet groove being arranged in the third range and extending from the upstream end portion in the second direction of the opening portion to the middle of the arrangement range of the first plurality of active elements and the second plurality of active elements in the second direction.

4. The semiconductor device according to claim 3, wherein: The first plurality of active elements are switch elements on the upper arm side of the U phase, the V phase, and the W phase, The second plurality of active elements are switch elements on the lower bridge arm side of the U phase, the V phase and the W phase, The passive elements are freewheeling diodes on the upper arm side and the lower arm side of the U phase, the V phase, and the W phase.

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