Abstract: It is presented a control device for driving an electric motor, wherein a drive control signal for the electric motor is arranged to be determined using a calculated rotor flux. A direct quadrature, dq, coordinate system relating to a rotor of the electric motor is used. The control device comprises a flux estimator arranged to determine the calculated rotor flux using a quadrature axis voltage, a measured direct axis current, a measured quadrature axis current, an angular velocity, stator resistance and a direct axis inductance and an actual torque calculator arranged to obtain an actual torque estimation using the calculated rotor flux, the measured direct axis current and the measured quadrature axis current. A corresponding method is also presented.

Abstract: It is presented a control device for driving an electric motor, wherein a drive control signal for the electric motor is arranged to be determined using a calculated rotor flux. A direct quadrature, dq, coordinate system relating to a rotor of the electric motor is used. The control device comprises a flux estimator arranged to determine the calculated rotor flux using a quadrature axis voltage, a measured direct axis current, a measured quadrature axis current, an angular velocity, stator resistance and a direct axis inductance and an actual torque calculator arranged to obtain an actual torque estimation using the calculated rotor flux, the measured direct axis current and the measured quadrature axis current. A corresponding method is also presented.

Abstract: It is presented a protection circuit for a drive circuit of a permanent magnet motor being powered by a main DC source. The protection circuit comprises a protection circuit DC source; a changeover switch being arranged to select an input to a gate of a main drive switch of the drive circuit, the input being selectable between an output of the protection circuit DC source and a second control signal; and a changeover control device connected to control the changeover switch, which changeover control device is arranged to ensure that the changeover switch is connected to the output of the second side of the protection circuit DC source when an overvoltage is detected.

Abstract: A cooling device comprises a main body (4) and an adapter device (5) arranged at an end (4a) of the main body. The main body is provided with a plurality of channels (6, 7) running from one to the other one of the oppositely located ends of the main body. A further adapter device is arranged at the other end of the main body and each of the adapter devices comprises two separate chambers (10, 11) and, for each of the two separate chambers, an input/output (10a, 11a) in fluid communication with the chamber, and holes (12, 13) providing fluid communication between the chamber and alternating ones of said plurality of channels, thereby providing two separate fluid path systems.

Abstract: A self-energizing, non-contacting sensing device for detecting movement of ferrous elements, methods of use and assemblies therewith. The device includes a permanent magnet, a pair of ferrous conductors, an inductor coil and a microprocessor. The ferrous conductors are attached to the permanent magnet with free ends of the ferrous conductors being spaced from one another to provide a gap. The gap provides an open circuit in the absence of the moving ferrous elements and a substantially closed circuit in the presence of the moving ferrous elements. When the circuit alters between open and closed states, in the absence and presence of the moving ferrous elements, respectively, an electromotive force imparted on the inductor coil generates an alternating current. The microprocessor is configured to detect the alternating current produced in the inductor coil, and thus, can assess whether the ferrous elements are moving in a normal or abnormal manner.

Abstract: An electric braking or clutching device includes a housing; an armature having an axis and disposed at the housing, the armature and the housing defining a radial air gap therebetween; and a coil configured to generate, when energized, a magnetic field at the housing and armature, a flux path of the field extending from the coil into the housing, from the housing into the armature, from the armature into the housing, and from the housing back to the coil, with the direction of the flux path from the armature into the housing being substantially radial in orientation.

Abstract: It is presented a gate driver circuit for driving an electric switch, the switch being arranged to control a main current using a gate signal. The gate driver circuit comprises: a non-linear capacitor means having a lower capacitance when an applied voltage is under a threshold voltage and a higher capacitance when an applied voltage is over the threshold voltage, wherein the non-linear capacitor is arranged to be connected between a high voltage connection point of the switch and a connection point for the gate signal; a current change rate sensor, the current change rate sensor being configured to detect changes in a main current of the electric switch and to control a gate signal of the electric switch depending on the current change; a gate buffer; and at least one current source, arranged to drive the gate buffer. The current change rate sensor is connected to control the current source to thereby control the gate signal of the electric switch.

Abstract: A ball screw assembly has an axially extending screw with an external helical groove and a nut with a through bore for receipt of the screw. The through bore has an internal helical groove adapted for cooperation with the external helical groove to define a ball raceway. A plurality of load bearing balls is disposed in the raceway for rolling contact with the internal and external grooves. A spacer is disposed between adjacent ones of the load bearing balls to prevent the balls from contacting one another. Each of the spacers has at least three pairs of diametrically opposite concave dimples adapted for contact with the load bearing balls at separate times from one another.

Abstract: A method, apparatus or computer program implements an overload prevention approach involving monitoring a speed of a motor; detecting an overload condition of the motor based on the monitored speed; and controlling an operation of the motor according to the detected overload condition.

Abstract: The present invention relates to an electrical drive unit comprising a circuit board, a plurality of components, attached to a first side of the circuit board, a heat sink, arranged on the first side of the circuit board, a positioning assembly, arranged on a second side of the circuit board opposite the first side of the circuit board. The circuit board comprises a plurality of holes between the first and second sides, where through the positioning assembly has a plurality of protrusions arranged against the plurality of components, such that each component of the plurality of components individually is pressed against the heat sink by the positioning assembly.

Abstract: An inverter type drive unit for feeding AC electric power of variable parameters to an electric motor has an electronic control section, and a power converting and output section which includes one or more identical power modules, each forming a complete 3-phase output stage. The power modules are arranged side-by-side in a multiplying direction and are clamped by retaining devices to a cooling structure. The power modules are connected in parallel to DC input terminals and to AC output terminals via conductive sheets which are insulated from each other. The DC connected conductive sheets cover substantially the entire physical surface area covered by the power modules so as to accomplish an even, simultaneous and low impedance DC current supply to all power modules.

Abstract: The present invention relates to a device functioning as an electric motor or actuator (100, 100?) comprising: a housing (110) encapsulating a rotating member (120, 120?), one or several arrangements (130, 130?) for generating a magnetic field due to electrical current, a displaceable shaft (140, 140?) at least partly having exterior grooves (141, 141?), said rotating member having a portion (121, 121?) with inner grooves (122, 122?) corresponding to grooves on said shaft (140, 140?). The device comprises at least one magnetic element (150, 150?) arranged on an outer surface of said rotating member (120, 120?) substantially perpendicular to extension direction of said grooves (122, 122?) for interaction with said arrangement (130, 130?) and rotating said rotating member.

Abstract: A heat sink comprises a base panel having a top surface and a bottom surface. A plurality of pin fins extend outwardly from the top surface and each fin has a cross-sectional configuration with two radiuses, a first radius and a second radius, wherein the first radius is larger than the second radius. The first and second radiuses are tangentially interconnected by intermediate portions, giving the pin fin cross-sectional configuration a raindrop shape, thereby generating low pressure drop across the heat sink by minimizing the drag force effects and maintaining large exposed surface area available for heat transfer.

Abstract: An electric braking or clutching device includes a housing; an armature having an axis and disposed at the housing, the armature and the housing defining a radial air gap therebetween; and a coil configured to generate, when energized, a magnetic field at the housing and armature, a flux path of the field extending from the coil into the armature, from the armature into the housing, and from the housing back to the coil, with the direction of the flux path from the armature into the housing being substantially radial in orientation.

Abstract: The present invention relates to an electrical drive unit comprising a circuit board, a plurality of components, attached to a first side of the circuit board, a heat sink, arranged on the first side of the circuit board, a positioning assembly, arranged on a second side of the circuit board opposite the first side of the circuit board. The circuit board comprises a plurality of holes between the first and second sides, where through the positioning assembly has a plurality of protrusions arranged against the plurality of components, such that each component of the plurality of components individually is pressed against the heat sink by the positioning assembly.

Abstract: An induction motor comprises a stator (10) and a rotor (20), which includes material essentially blocking magnetic flux at high frequencies. A difference in number of stator slots and rotor slots is chosen so that the inductance of a winding provided in a stator slot is different from the inductance of a winding provided in another stator slot. A sense means, such as stator winding or separate sense winding, is provided in at least one of the stator slots and the sense means is arranged to allow measuring of the inductance thereof. The sense means constitutes an integrated sensor, which is both inexpensive and reliable. A method of sensing the rotor position and/or speed of an induction motor is also described.

Abstract: This invention propose a way of controlling the flux density in a current transformer to keep the transformer core saturated between two consecutive measurements in a sampling measurement system. Saturation disables transformation of primary to secondary current, and thereby disables losses in the secondary circuit during this time. Both AC and DC currents are possible to measure. The use of saturation of the transformer core also permits the core to be designed physically very small. In order to get effective and accurate low power consuming measurements, both the magnetic fields originating from primary current flowing in the primary winding and external magnetic fields must be symmetrically physically spread in the transformer core. This greatly limits the possible physical arrangement of the primary winding.

Abstract: A power terminal for electrical connection of an electric cable to a circuit board comprises a main body (8a) having a central longitudinal axis and means (12, 12a) for attaching a cable to the main body. An eccentric body (8b) integral with the main body (8a) and having a through hole (13) is arranged to receive a screw. A space (20) is provided at the bottom of the power terminal adjacent to the eccentric body. This configuration provides a means for securing the terminal in an easy and efficient way while also providing for mounting of a current measuring device, for example.

Abstract: A circuit arrangement comprises a circuit board (10), a semi-conductor (12) provided on a first side of the circuit board, and a heat sink (15) provided on a second side of the circuit board opposite to the first side and in heat transferring contact with the power semi-conductor. A heat conductive element (13) is provided in a hole (10a) in the circuit board, wherein the heat conductive element is positioned in heat transferring contact with both the semi-conductor and the heat sink for transfer of heat generated by the semi-conductor to the heat sink. A circuit arrangement is provided, wherein the provision of a low thermal resistance path through the circuit board by means of heat conductive elements provides a compact circuit arrangement well suited for assembly by means of an automated surface mounting process.

Abstract: A linear motion bearing assembly (20) as provided for movement along a splined shaft (10). The rolling element retainer of the bearing assembly (20) is assembled from a plurality of arcuate interengageable self-contained rolling element retainer segments (22). Each of the rolling element retainer segments (22) includes at least one rolling element track (30) having a load bearing portion (34) and a return portion (36). At least one load bearing plate (44) is axially positioned in each segment and serves to receive and transmit loads from the bearing rolling elements (32) in the load bearing portion (34) of the ball tracks (30). An extended housing retainer structure encloses all of the exposed exterior surfaces of the rolling element retainer segments (22) and is configured and dimensioned to maintain the rolling element retainer segments (22) in position and to receive a load either directly or indirectly from the load bearing plates (44).