A power semiconductor device includes a planar rectifying element, a base electrode, a first solder layer, a lead electrode, a second solder layer, and first and second sealing portions. The base electrode is electrically connected to the rectifying element via the first solder layer formed on a first surface of the rectifying element. The lead electrode is electrically connected to the rectifying element via the second solder layer formed on a second surface of the rectifying element. The first sealing portion is formed of a first resin and provided in a recess; the recess is formed by the first surface of the rectifying element and the first solder layer or by the second surface of the rectifying element and the second solder layer. The second sealing portion is formed of a second resin and separately from the first sealing portion to cover an outer surface of the first sealing portion.

A system and a method for producing fracturing fluid, comprising: receiving source fluid from one or more inlet manifolds of a single transport, driving a first pump mounted on the single transport to route the source fluid from the inlet manifolds into a hydration tank mounted on the single transport, driving a second pump mounted on the single transport to route hydrated fluid produced by the hydration tank to a blending tub mounted on the single transport, and discharging fracturing fluid produced by the blending tub to one or more outlet manifolds of the single transport.

A synchronous machine (100) includes a housing, a shaft (106) to mount a three-phase rectifier (124), main motor (116) and a rotating transformer (RT) (108). The main rotor (110) is concentrically and co-axially mounted on shaft (106), and main stator (112) is concentrically and co-axially assembled over main rotor (110). Main rotor (110) includes Direct Current field windings and main stator (112) includes Alternating Current poly-phased distributed windings. Further, the RT (108) includes an RT rotor (120) and RT stator (122). RT rotor (120) and RT stator (122) may include AC poly-phase distributed windings and second predefined number of poles. Further, RT rotor (120) may be configured to be rotatably coupled on first end (106A) of shaft (106). The RT stator (122) may be configured to concentrically and co-axially assembled over RT rotor (120).

A synchronous machine (100) includes a housing, a shaft (106) to mount a three-phase rectifier (124), main motor (116) and a rotating transformer (RT) (108). The main rotor (110) is concentrically and co-axially mounted on shaft (106), and main stator (112) is concentrically and co-axially assembled over main rotor (110). Main rotor (110) includes Direct Current field windings and main stator (112) includes Alternating Current poly-phased distributed windings. Further, the RT (108) includes an RT rotor (120) and RT stator (122). RT rotor (120) and RT stator (122) may include AC poly-phase distributed windings and second predefined number of poles. Further, RT rotor (120) may be configured to be rotatably coupled on first end (106A) of shaft (106). The RT stator (122) may be configured to concentrically and co-axially assembled over RT rotor (120).

Methods, systems, and devices are disclosed for wind power generation. In one aspect, a wind power generator includes a support base; inductors positioned over the support base in a circular array; an annulus ring track fixed to the base support and providing a circular track around which the inductors are located; an annulus ring rotor placed on the annulus ring track and engaged to rollers in the circular track so that the annulus ring rotor can rotate relative to the an annulus ring track, in which the annulus ring rotor include separate magnets to move through the circular array of inductors to cause generation of electric currents; and a wind rotor assembly coupled to the annulus ring rotor and including wind-deflecting blades that rotate with the rotor and a hollow central interior for containing a wind vortex formed from deflecting wind by the blades to convert into the electric energy.

A rotating electric machine includes a machine main body, a frame member and a rectifier. The machine main body is configured to generate alternating current. The frame member holds the machine main body. The rectifier is provided axially outside the frame member and has a rectification circuit configured to rectify the alternating current generated in the machine main body into direct current. The rectifier includes first and second heat sinks that are located to axially overlap each other, first rectifying elements mounted to the first heat sink and constituting an upper arm of the rectification circuit, and second rectifying elements mounted to the second heat sink and constituting a lower arm of the rectification circuit. The second heat sink is located closer than the first heat sink to the frame member. The surface area of the second heat sink is greater than the surface area of the first heat sink.

An electric machine (21) having a stator (20) and having a rotor (29) rotatably mounted to the stator (20) is specified. The stator (20) comprises a stator winding (24), at least three teeth (23), and at least three grooves (22). In each case, one tooth (23) of the stator (20) is arranged between two grooves (22) along a circumference of the stator (20), and the stator winding (24) has at least three coils (25), wherein each of the coils (25) is wound around a tooth (23) of the stator (20), so that the stator winding (24) is a concentrated winding. In addition, the winding direction of all coils (25) is the same, each of the coils (25) is designed to be fed with its own phase current, and the stator (20) is designed to generate at least two rotary fields having different numbers of pole pairs independently of each other, in particular simultaneously. In addition, an activation unit (40) for the electric machine (21) and a method for operating an electric machine (21) are specified.

An electric machine (21) having a stator (20) and having a rotor (29) rotatably mounted to the stator (20) is specified. The stator (20) comprises a stator winding (24), at least three teeth (23), and at least three grooves (22). In each case, one tooth (23) of the stator (20) is arranged between two grooves (22) along a circumference of the stator (20), and the stator winding (24) has at least three coils (25), wherein each of the coils (25) is wound around a tooth (23) of the stator (20), so that the stator winding (24) is a concentrated winding. In addition, the winding direction of all coils (25) is the same, each of the coils (25) is designed to be fed with its own phase current, and the stator (20) is designed to generate at least two rotary fields having different numbers of pole pairs independently of each other, in particular simultaneously. In addition, an activation unit (40) for the electric machine (21) and a method for operating an electric machine (21) are specified.

In some embodiments, a system includes a machine segment that includes multiple coils. Each coil is electrically isolated from the other coils in the machine segment, and each coil is electrically coupled to at least one electrical terminal to provide electrical access to the coil. Each electrical terminal provides electrical access to the coil to which it is electrically coupled such that the coil can be removably electrically coupled to an electrical circuit. The machine segment is also configured to be removably mechanically coupled to a second machine segment to form at least a portion of a stator or a portion of a rotor.

An electrical sub-assembly comprises a stator having a plurality of coils and a cooling means attached to the stator. The electrical sub-assembly further comprises a plurality of pairs of diodes attached to the cooling means, each pair of diodes being in antiparallel configuration and having three electrical terminals. One of the three electrical terminals is a common terminal shared by both diodes in each pair of diodes. A plurality of busbars electrically connect each of the diodes to at least one of the plurality of coils via one or more of the electrical terminals. In use, the cooling means is configured to simultaneously cool the stator and the plurality of diodes. The electrical sub-assembly may have particular application as a part of a switched reluctance machine.