Distributed Torque Generation System and Method of Control

Abstract

An apparatus for an electrically powered terrestrial vehicle applies electrical energy to front wheels and to rear wheels. A control system receives desired acceleration inputs and provides target torque requirements to a plurality of adaptive field-oriented motor control circuits. One or more three-phase alternating current synchronous motors receive voltage magnitude and voltage frequency to generate torque, which is applied through a reduction gear. The reduction gear may be coupled to one wheel or a pair of wheels. Forward acceleration is favored over deceleration by a chosen ratio between reduction gearing of the front axle versus reduction gearing of the rear axle.

We claim: 
     
         1 . A system comprising:
 a plurality of wheels, each wheel being one of a front wheel and a rear wheel;   a plurality of reduction gears, each reduction gear being one of a front reduction gear and a rear reduction gear;   a plurality of alternating current electric motors (AC motors), each motor mechanically coupled to at least one wheel by at least one reduction gear;   a plurality of adaptive field-oriented motor control circuits (AF-OC), each AF-OC electrically coupled to one or more AC motors to provide voltage magnitude and voltage frequency and communicatively coupled to a vehicle control unit (VCU) to receive digitally encoded signals which specify voltage magnitude and voltage frequency; and   the vehicle control unit to budget torque among one of all wheels, front wheels, and rear wheels according to indicia for desired acceleration received from an operator.   
     
     
         2 . The system of  claim 1  wherein a pair of wheels are coupled to one reduction gear coupled to one AC motor. 
     
     
         3 . The system of  claim 1  wherein each front wheel is coupled to one front reduction gear coupled to one AC motor, and each rear wheel is coupled to one rear reduction gear coupled to one AC motor. 
     
     
         4 . The system of  claim 1  wherein each AC motor is a 3-phase electric motor. 
     
     
         5 . The system of  claim 1  wherein a front reduction gear has a first reduction ratio and a rear reduction year has a second reduction ratio. 
     
     
         6 . The system of  claim 5  wherein the first reduction ratio is greater than the second reduction ratio. 
     
     
         7 . The system of  claim 5  wherein the first reduction ratio is less than the second reduction ratio. 
     
     
         8 . The system of  claim 1  further comprising sensors to measure wheel rotational speed (spin). 
     
     
         9 . The system of  claim 1  further comprising sensors to measure wheel slip relative to a surface. 
     
     
         10 . The system of  claim 1  further comprising one or more generators or stores of direct current electricity coupled to each AF-OC. 
     
     
         11 . A method for optimizing energy efficiency and improving vehicle performance executing instructions in a processor to
 receive indicia for desired acceleration from an operator;   receive measurements of wheel slip and wheel spin;   read stored values for each reduction ratio and maximum slip,   determine positive or negative torque for each wheel; and,   transmit digitally encoded voltage maximum and voltage frequency to each AF-OC.   
     
     
         12 . The method of  claim 11  wherein more energy is provided to rear wheels when accelerating forward. 
     
     
         13 . The method of  claim 11  wherein more energy is provided to front wheels when not accelerating forward. 
     
     
         14 . The method of  claim 11  wherein the voltage maximum and voltage frequency are limited to enable no more than A % slippage when accelerating and -D % slippage when decelerating. 
     
     
         15 . The method of  claim 11  wherein all positive torque is provided to rear wheels when forward acceleration is desired. 
     
     
         16 . The method of  claim 11  wherein all negative torque is provided to front wheels when only deceleration is desired. 
     
     
         17 . The method of  claim 11  wherein all positive torque is provided to front wheels when only air and road resistance needs to be overcome. 
     
     
         18 . An apparatus for controlling an adaptive field-oriented electric motor comprising:
 a current speed determination circuit;   a desired acceleration determination circuit;   a torque generation distribution circuit;   and   a voltage magnitude and voltage frequency determination circuit;   
       whereby only front wheel adaptive field-oriented motor control circuits receive voltage magnitude and voltage frequency torque generation signals when a threshold speed has been attained and no further acceleration is desired, and 
       whereby only rear wheel adaptive field oriented motor control circuits receive voltage magnitude and voltage frequency torque generation signals when acceleration is desired and a threshold speed has not been exceeded. 
     
     
         19 . The apparatus of  claim 18  which controls only one wheel at any forward or reverse speed below a threshold. 
     
     
         20 . The apparatus of  claim 18  which controls all four wheels on the condition of inclement weather, poor road quality, or aggressive cornering.