Gm Global Technolgoy Operations, Inc.

Thomas A Radomski

Alexander Kade

Sam M Karadsheh

Michael F Matouka

Paul D Agarwal

Larry J Leaf

Roger D Fruechte

An automotive alternator has a rotor including a first single coil Lundell portion and a second permanent magnet portion. Permanent magnet poles are axially aligned in spaced adjacency with the fingers of the magnetic members of the Lundell portion of the machine. The current through the field coil of the Lundell portion is controllable in magnitude and direction to control the output of the machine.

Alternating current generator

An alternating current generator for supplying the electrical loads on a motor vehicle. The generator has a stator core that carries a three-phase stator or output winding. The rotor of the generator has two claw pole members that are magnetically connected by a core. A field coil is disposed about the core. The pole fingers of the claw pole members are interleaved and a plurality of permanent magnets are secured to side surfaces of the pole fingers such that there is a permanent magnet between each pair of adjacent pole fingers. The generator is arranged such that flux developed by the permanent magnets can flow through a closed magnetic path that bypasses the air gap between the rotor and stator and such that energization of the field coil with unidirectional current cause permanent magnet flux to traverse the air gap between the rotor and stator and thereby provide a useful flux for generating voltage in the stator winding.

An alternating current generator for supplying the electrical loads on a motor vehicle. The generator has a stator core that carries a three-phase stator or output winding. The rotor of the generator has two claw pole members that are so oriented that the fingers of the pole members are aligned. Disposed between the two pole members is a third pole member having projections disposed between the aligned fingers of the claw pole members. The rotor has two field coils which are so arranged and energized that the magnetic polarity of the two claw pole members is the same and opposite the magnetic polarity of the third pole member. One of the field coils can be replaced by a permanent magnet and when this is done the generator is provided with a magnetic circuit that can divert permanent magnet flux away from the stator core. Flux diversion is controlled by supplying unidirectional current to the field winding under the control of a voltage regulator.

A dual voltage motor vehicle electrical system wherein batteries are series connected across the direct voltage output terminals of a generator. The system has a DC to DC converter that operates in a first mode as an equalizer to maintain the batteries in a substantially equal state of charge. When an electric starting motor is energized to crank the engine of the vehicle the converter is switched to a second mode of operation wherein it provides a substantially constant output voltage that is applied to certain electrical loads on the vehicle that require a stable voltage. The converter responds to a first reference voltage that is provided by a voltage divider connected across the batteries when operating in the first mode and responds to a second reference voltage provided by a constant voltage device when operating in the second mode. The system switches between the reference voltages, depending upon the mode of operation that is being used.

Dual voltage motor vehicle electrical system

A dual voltage motor vehicle electrical system wherein a pair of batteries are connected in series across the direct voltage output terminals of a bridge rectifier that is connected to the output winding of an alternating current generator. First and second groups of controlled rectifiers are connected between a junction of the batteries and the generator output winding. In low speed operation of the generator the groups of controlled rectifiers are alternately biased conductive. The time period of conduction of the groups of controlled rectifiers is controlled as a function of the difference in the voltages across the respective batteries. At a higher speed of the generator one of the two groups of controlled rectifiers is biased conductive, dependent upon the relative magnitudes of the voltages across the batteries.

Dual voltage electrical system

A starter/generator in combination with a dual battery dual voltage motor vehicle electrical system and an equalization circuit for maintaining substantially equal charge on the batteries. In starting, the starter/generator is operated as an equivalent series motor from the serial combination of the two batteries to crank the engine. Upon starting, the starter/generator supplies charging current at one or the other of the system voltages, depending on the engine speed. At all times, the equalization circuit transfers energy from one battery to the other as required to maintain balanced battery voltages.

Motor vehicle electrical system including a combined starter/generator

A speed selection control is provided for a DC electric accessory motor having an armature winding and being mounted on a vehicle having a high reactance, multiphase alternator with a diode bridge rectifying output circuit, a battery connected across the output circuit and a voltage regulator controlling the voltage across the output circuit to a substantially constant voltage. One end of the motor armature winding is connected to the ungrounded end of the output circuit, and the other end of the motor armature winding is connected to the junctions of the diodes of each phase of the output circuit through a plurality of switched rectifiers, each having an anode connected to the other end of the motor armature winding and a cathode connected to the junction of the diodes of one phase of the output circuit. A switch control provides a continuous activation signal to selected numbers of the switched rectifiers, so that the motor armature receives electric power from the alternator in a substantially rectangular voltage wave with duty cycle determined by the number of switched rectifiers activated and thus the number of alternator phases used.

Speed selection control for vehicle mounted electric accessory motor

A transistor bridge driver circuit having reduced operating losses, comprising a driver transistor connected to supply drive current to diagonally opposed bridge transistors and an auxiliary transistor effective when biased conductive to divert driver current away from one of the diagonally opposed bridge transistors. Switching losses are minimized because the bridge is operated in the one quadrant control mode and driver losses are minimized because one driver circuit controls the conduction of two diagonally opposed bridge transistors.

Bridge driver circuit for a DC electric motor

The torque gain of an electric motor assisted power steering system is modified as a function of the estimated level of road load friction such that the relationship between the operator exerted steering torque and the resulting rate of steer is substantially insensitive to a reduction in the level of road load. The road load is estimated as a function of the operator exerted steering torque, the torque assist provided by the electric motor, and the resulting steer rate.

Road load insensitive electric power steering system

The current in each phase of a multiple phase chopper is sensed and compared to a reference overcurrent value. Any chopper phase reaching overcurrent and any chopper phase on for a longer period of time are turned off immediately. The conduction periods of chopper phases that have been on for a shorter period of time than the overcurrent phase are similarly shortened to maintain balanced phase conduction and minimize the ripple content of the source current. The phase relationship among the various chopper phases is adjusted in response to an overcurrent turn-off to allow the commutation network associated with such phase to be adequately charged before the generation of a current turn-on for another phase.

Multiple phase chopper current limiting

A multiple phase SCR chopper controller for establishing a normal phase relationship among the various SCR phases and for modifying the normal phase relationship for input signals for which the SCR commutation networks cannot be sufficiently charged. These input signals correspond to conduction period overlap, and the modified phase relationship avoids chopper commutation failure under such conditions.

Phase control for a multiple phase SCR chopper

A circuit for protecting the transistor of a high current transistor chopper from damage due to inductive energy stored in the chopper circuit when the transistor is biased nonconductive. The inductive energy charges a capacitor connected in parallel with the transistor, and a return circuit returns the energy stored in the capacitor to the source while the transistor is nonconductive and to the load when the transistor is subsequently biased conductive.

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Utica, MI, United States of America

Thomas A Radomski