Abstract: A polyphase electric motor has a rotor, a stator with a plurality of slots, a plurality of main windings and a plurality of auxiliary windings installed in slots of the stator, and a main winding and an auxiliary winding that correspond to a selected phase of an alternating current power source. The auxiliary windings are connected to the motor terminals through a plurality of capacitors, and the auxiliary windings and corresponding capacitors are connected in parallel to the main windings. The main winding and the auxiliary winding of the selected phase are offset by about 60 to about 120 electrical degrees. A power of the plurality of main windings is at least 75% of a power of the polyphase electric motor at full load rating and the power of the plurality of main windings is motoring at 25% of the full load rating.

Abstract: A polyphase electric motor has a rotor, a stator with a plurality of slots, a plurality of main windings and a plurality of auxiliary windings installed in slots of the stator, and a main winding and an auxiliary winding that correspond to a selected phase of an alternating current power source. The auxiliary windings are connected to the motor terminals through a plurality of capacitors, and the auxiliary windings and corresponding capacitors are connected in parallel to the main windings. The main winding and the auxiliary winding of the selected phase are offset by about 60 to about 120 electrical degrees. A power of the plurality of main windings is at least 75% of a power of the polyphase electric motor at full load rating and the power of the plurality of main windings is motoring at 25% of the full load rating.

Abstract: A polyphase electric motor has a rotor, a stator with a plurality of slots, a plurality of main windings and a plurality of auxiliary windings installed in slots of the stator, and a main winding and an auxiliary winding that correspond to a selected phase of an alternating current power source. The auxiliary windings are connected to the motor terminals through a plurality of capacitors, and the auxiliary windings and corresponding capacitors are connected in parallel to the main windings. The main winding and the auxiliary winding of the selected phase are offset by about 80 to about 100 electrical degrees. A power of the plurality of main windings is at least 75% of a power of the polyphase electric motor at full load rating and the power of the plurality of main windings is motoring at 25% of the full load rating.

Abstract: A stator for an alternating-current induction machine, the stator comprising a cylindrical stator core. The stator may also comprise a first stator tooth. The first stator tooth may comprise a proximal end extending from the cylindrical stator core and a distal end comprising an outer surface positioned to face a rotor. A first arc of the outer surface may be eccentric relative to the cylindrical stator core. Various additional stator designs and methods are also disclosed.

Abstract: An electromechanical machine includes a stator. A rotor is configured to rotate relative to the stator about a rotational axis. A coil extends about the axis and is wound on a bobbin. The bobbin surrounds the axis and has a circumferentially extending pocket in which the coil is located. The bobbin further has a circumferentially-extending overhang section that extends directly over at least a portion of the coil.

Abstract: A fault-handling system for a 2-phase motor. When an electric motor is used for power assist in a steering system in a vehicle, malfunctions can cause loss of assist, and detectable vibration. The invention utilizes a 2-phase motor in such an application, and implements alternate modes of operation when certain malfunctions occur, thereby maintaining the assist function in situations wherein the function would otherwise be lost or reduced.

Abstract: An apparatus and method for controlling sinusoidal currents in inductive loads during zero-crossing to reduce distortion. The apparatus and method utilizes first and second PWM signals during a single PWM cycle to apply opposite voltage signals to obtain a net desired voltage across the inductive load. The voltage applied to the load is compared with a threshold and, when the applied voltage is greater than the threshold, normal PWM signals are applied to the load, and when the applied voltage is less than the threshold, an adjusted voltage formed of first and second PWM signals is applied to the load.

Abstract: A control system for an electric motor. Field Oriented Control, FOC, uses a digital control system, and attempts to maintain the rotating stator magnetic field ninety degrees ahead of the rotor field, in order to maximize torque. However, if a three-phase motor is used, which is very common, large amounts of computation are required, to convert from a three-phase coordinate system to an orthogonal coordinate system. The invention replaces the three-phase motor with a two-phase motor, which has been found to impose certain additional costs, but also provides benefits.

Abstract: A control system for an electric motor, of the type used to deliver mechanical power to a power-steering system in a vehicle. In one form of the invention, at high motor speeds, an inverter is requested to deliver a pseudo-sinusoidal voltage having peak-to-peak value which a vehicle battery cannot attain. Consequently, the pseudo-sinusoidal voltage delivered to the motor is clipped at some value: the tops, and bottoms, of the pseudo-sinusoid peaks are chopped off. This clipping brings current in the phases closed to being in-phase with the voltage.

Abstract: A control system for an electric motor used to provide mechanical power to a power steering system in a vehicle. The motor is of the two-phase type with an independent winding for each phase, or of the three-phase type with two independent stator windings. Two inverters are provided, one for each winding. Each inverter provides AC current to run the motor. If a fault is detected in an inverter or its stator winding, current is terminated to that inverter, and the motor is run using the other winding. In addition, if the vehicle battery is installed with incorrect polarity, components within the inverters can be destroyed. The invention detects the incorrect polarity, and blocks current to the inverters.

Abstract: An apparatus and method for controlling sinusoidal currents in inductive loads during zero-crossing to reduce distortion. The apparatus and method utilizes first and second PWM signals during a single PWM cycle to apply opposite voltage signals to obtain a net desired voltage across the inductive load. The voltage applied to the load is compared with a threshold and, when the applied voltage is greater than the threshold, normal PWM signals are applied to the load, and when the applied voltage is less than the threshold, an adjusted voltage formed of first and second PWM signals is applied to the load.

Abstract: A control system for a brushless DC motor, preferably used in a power steering system in a vehicle. Presently delivered torque is computed without measuring currents in the motor. A demanded torque signal is received, and a torque error signal is produced. The torque error signal is modified by an inertial torque component, if the motor is accelerating. In response to the modified error signal, the control system first attempts to increase motor torque by increasing motor voltage, if that is possible, without increasing magnetic field which is parallel with the magnetic field of the rotor. If that is not possible, then motor voltage is held fixed, and the magnetic field just mentioned is increased.

Abstract: An improved stator for an electric motor. In one form of the invention, each stator slot in a stator contains only coils of a single phase. Thus, if a short occurs in that coil, no other phase is present in the slot for the short to connect with. In another form of the invention, pre-formed coils are constructed, having hollow cores. Each coil is inserted over a stator tooth, and then additional structure is added to form a rim from which the teeth extend, somewhat like spokes on a wheel.

Abstract: A fault-handling system for a 2-phase motor. When an electric motor is used for power assist in a steering system in a vehicle, malfunctions can cause loss of assist, and detectable vibration. The invention utilizes a 2-phase motor in such an application, and implements alternate modes of operation when certain malfunctions occur, thereby maintaining the assist function in situations wherein the function would otherwise be lost or reduced.

Abstract: A control system for an electric motor. Field Oriented Control, FOC, uses a digital control system, and attempts to maintain the rotating stator magnetic field ninety degrees ahead of the rotor field, in order to maximize torque. However, if a three-phase motor is used, which is very common, large amounts of computation are required, to convert from a three-phase coordinate system to an orthogonal coordinate system. The invention replaces the three-phase motor with a two-phase motor, which has been found to impose certain additional costs, but also provides benefits.

Abstract: An electric motor having reduced cogging torque. Motors have stator teeth separated by a slot, or space, which is filled with air and/or copper. The magnetic field present in the space is reduced, compared to that present in the iron cores. Thus, when the rotor rotates, it sees a changing magnetic field as it passes a tooth face, then a slot, and then a neighboring tooth face. This change can produce a force or cogging torque in the motor. The invention changes the geometry of the tooth face and slot to reduce variation of reluctance and increase overall flux of the stator.

Abstract: System for reducing electronic noise in a radio in a vehicle. Pulse Width Modulated, PWM, motors used in a vehicle receive pulses of electric current. These pulses have a Fourier spectrum of harmonics which can be picked up by a radio in the vehicle, causing the radio to produce unwanted noise. The invention reduces the noise by continually varying the base frequency of the PWM pulses, to thereby vary the spectrum of the noise. This varying spectrum is more difficult for humans to detect.

Abstract: A control circuit for a motor having at least two windings is used to optimize noise reduction by controlling the deenergization of each winding in a two-stage decay. The duration of the two-stage decay and particularly the first decaying current portion is controlled by a controller operatively coupled to a switch device. The duration of the first decaying current portion is varied between the various phases of the motor to provide optimum noise reduction.

Abstract: An encoder circuit particularly suited for a switched reluctance (SR) electric motor includes a single switch and a plurality of encoder windings. Each one of the plurality of encoder windings is connected to the switch. When closed, the switch initiates current flow through the windings. A plurality of comparators are connected to the encoder windings. Each comparator has an output having a first state and second state. The output changes state when the encoder winding current exceeds a reference current level. A counter connected to the comparator outputs measures the time that each winding current is below the reference current level (i.e., before changing state). The switch simultaneously disconnects the encoder windings from a power supply after each one of the plurality of encoder windings reaches the reference current (i.e, after each of the comparators changes state).

Abstract: A switched reluctance electric motor is disclosed that includes a stator portion having a plurality of stator poles. Adjacent stator poles are wound with energizing windings and which are connected in-series to form a respective one of a plurality of motor phases of the electric motor. A rotor portion of the electric motor is also disclosed, and is supported for rotation relative to the stator, and which also includes a plurality of rotor poles. An electrical conductor having first and second ends is disposed about the adjacent stator poles for each one of the plurality of motor phases. The first and second ends of each electrical conductor are shorted together to thereby minimize induced flux linkages in non-energized motor phases when one of the motor phases is energized.