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Lennart Stridsberg

Gunnar Rodin

An electric motor/generator includes a rotor with magnets mounted on the surface of the rotor, the magnets facing the stator over a gap. The magnets have a very high flux density but a limited ability to withstand high stator currents at high temperatures, preferably magnets made of the N48H material. By providing rotor magnet cooling means that reduces the temperature of the magnets by a cooling fluid, use of magnets with lower maximum working temperature and higher flux density is permitted and thereby higher flux can be obtained from the magnets.

Cooled magnet motor

Set of playing cards

A fast automated gear shift operation is performed using a powertrain in a hybrid vehicle, the powertrain including a gear box, an engine, at least one controllable motor, a torque ripple damping device, a mechanical connecting device for connecting or disconnecting the engine to or from, respectively, wheels of the vehicle. In the gear shift operation the motor is controlled to perform a sequence of steps in which different torques are delivered by the motor to temporarily change the speed thereof. The torques are selected so that they to reduce the mechanical tension over at least one elastic part of the powertrain. Hence it can be achieved, that during at least a period during the gear shift operation torques over mechanical elements in the gear box cooperating in the current gear and/or over the mechanical connecting device are eliminated or at least strongly reduced. The period should be sufficiently long so as to permit disconnection of said mechanical elements cooperating for the present gear and/or to permit disconnection of the mechanical connection device.

Hybrid vehicle with soft shafts

A position transducer for a rotary member such as the rotor of a motor has a rotating encoder disc and flat, disc-shaped elements interacting with the encoder disc to produce position dependent signals. The encoder disc has at least one active element such as metal surfaces configured so that signals from one of several portions or sectors of the encoder system are not transferred to another portion or sector, thus permitting the position transducer to be split into several position detectors that can operate independently of each other without having signals from one position detector affecting the other position detectors. The position detectors can cover individual circular sectors or concentric rings and e.g. be based on sensing the capacitive coupling between transmitter and sensor electrodes located on opposite sides of the encoder disc. The components of the transducer can be assembled with substantial air gaps between them and be made from materials that are not easily destroyed by corrosion and contaminants like dust particles, water, oil or lubricant grease. The position transducer also permits detecting multiturn rotation without additional mechanical components.

Redundant compact encoders

An actuator and movement linkage system for moving a load, such as a control surface of aircraft, in relation to a carrying structure includes an electric motor system, an actuator device connectable or connected to the load to move the load, the actuator device connected to the electric motor system to be driven thereby, and transfer units provided for mechanically connecting the actuator device to move the load. Fault tolerant and release devices are provided both in the electrical motor system and in the actuator device to make the actuator and movement linkage system fault tolerant to at least single faults in the actuator and movement linkage system,

Actuator and movement linkage system

An electromagnetic rotary actuator is driven by a single-phase voltage. Permanent magnets on a rotor interact over a part-cylindrical small airgap with a soft-iron stator having pole teeth that carry at least one winding for rotating the rotor within a limited angular range, the airgap having a high flux density. The windings are applied around those of the pole teeth that are centrally located. The permanent magnets and stator poles have the same angular pitch. The actuator is compact having a low total length and has a high output power/loss ratio and allows a fast response. It can be built with a low thermal resistance to an enclosure or casing by having the coils being in direct mechanical contact therewith.

Electric motor

A brushless electric motor system comprises a rotor and a stator comprising poles. Electrical phase windings have coils (U, V, W) wound around the poles. Power switches (T) controlled by a control device supply electric current the windings from positive and negative rails connected to power supply. For each phase at least one group of four power switches arranged in a H-bridge configuration is provided. The coils of each phase winding are preferably divided into winding group (U, Ua-, V, V, W, W) and the electric conductor of each winding group is then electrically conductor of the other winding groups. Then four power switches arranged in an H-configuration is provided for each winding group. The use of power switches in H-bridge configurations allows the faulty windings or winding groups to be disabled and that the rest of the windings or coils can be used for driving the rotor, this giving the motor system a high reliability. The current supplied to other windings or winding groups can then be increased to compensate for the faulty group. The coil groups can be separated from other coil groups by unwound stator poles. Current sensors () can sense the current in each winding group and be used to detect whether the currents are too high. The sensed currents can be used to identify fault conditions in the system so that then suitable switches can be disabled, disconnecting a faulty winding group.

High reliability motor system

An encoder for detecting the angular position of a shaft of an electric motor comprises an encoder disc ( ) having tracks ( ) sensed by detectors in reading heads ( ). Analog position signals from the detectors are sampled in sampling circuits ( ) at times given by sampling pulses issued by a device such as a counter ( ). The sampled analog values are converted to digital values by a converter ( ) and provided to a local processor ( ) calculating position values. The local processor sends commands to the device ( ) to issue sampling pulses at accurately defined times, normally regularly spaced in time. The local processor also receives, from a central processor, read command signals commanding to it provide position values. These read command signals normally arrive rather regularly but are not synchronised. In order to provide positions values at suitable times after receiving the read command signals, the local processor can send its commands earlier or later, in relation to the normal regular rate.

Position transducer

A method and an apparatus control a car equipped with an automatic transmission having a lockup clutch. When the lockup clutch is in the lockup state, a variation of a generated torque is detected. When the range of the torque variation detected exceeds a predetermined value, an engine torque is reduced by controlling the engine, and the automatic transmission is controlled to compensate for a reduction of the driving torque due to a reduction of the engine torque. Thus, the speed change ratio is changed to the low gear side. The control unit includes a unit for controlling an output torque of an engine according to a command value, a unit for changing the transmission ratio of the automatic transmission, a unit for detecting a variation of the engine torque, a unit for deciding a target driving torque, a unit for reducing a torque command value when the range of a detected variation of the torque has exceeded a predetermined value when the lockup clutch was in the lockup state, and a unit for deciding a transmission ratio at which the reduction of the driving torque due to the reduction of the engine torque is compensated for.

Hybrid powertrain

A compact position and velocity transducer having a high speed resolution and a fast speed response and that does not place much demand on the precision of the bearings. The transducer includes an optical encoder that, when assembled in motors, is assembled on a short protruding part of the rotor close to the torque-creating parts. The optical incremental encoder signals are fed both to a moderate frequency digital counter that counts 4 counts per basic encoder period and to an A/D-converter that samples and digitizes the primary encoder analog signals. A processor uses a linearization algorithm on the sampled and digitized signals that yields position information that is locally highly continuous.

A position transducer has a moving modulating portion that can move to various positions through rotation, for example. The position transducer provides at least one analog signal that varies periodically with the moving position of the modulating portion, where the movement of the modulating portion has a period. The analog signal is provided to a converter that converts the analog signal into digital information which is applied to a computing arrangement to provide information as to the position of the modulating portion by using at least one transformation including stored information as to deviations of the periodic variation of the analog signal relative to a sinusoidal shape having a constant amplitude for all periods of movement of the modulating portion.

An encoder disc (,) of an optical position transducer is mounted on a short protruding part (,) of a rotor (,) of an electric motor close to torque creating parts. One part of the optical system, normally the light emitter part (,), is insertable between the rotor (,) and the encoder disc (,) after the insertion of the rotor-encoder disc assembly into the motor stator case (,). The optical incremental encoder signals are fed both to a moderate frequency digital counter that counts 4 counts per basic encoder period and to an A/D-converter that samples and digitises the primary encoder analog signals. A synchronising network ensures that the primary encoder digitised signal corresponds to the correct state of the digital counter. More than one decoder head can be used to compensate for the bearing play common in servo motors having varying axial loads. This construction gives a high speed resolution and fast speed response, is very compact and operates with modest demands on bearing precision.

A position transducer is provided that includes an encoder disc and at least two detector devices arranged to read at least one track on the encoder disc having low resolution in order to produce position signals. The detector devices each provide position signals to a processing device having a substantial phase difference therebetween. The signal processing device can determine movements of the encoder disc based upon the signals provided by the detector devices and the detector devices can be energized with a low duty cycle during a low power mode.

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Stockholm, Sweden

Lennart Stridsberg