Electrical propulsion systems for a vehicle
First Claim
1. [.A golf car.]. .Iadd.An electrically powered vehicle .Iaddend.having at least one driven wheel .[.and adapted for carrying at least one person and golf equipment on a golf course, the golf car including.]. .Iadd.the vehicle including.Iaddend.:
- a direct current electric drive motor having a separately excited field winding and a separately excited armature winding;
a battery for supplying direct current electric power to said drive motor;
.[.a foot operated.]. an accelerator for selectively establishing the speed of said vehicle between zero velocity and a preset maximum vehicle speed;
control means interconnecting said battery to said drive motor, said control means included;
(i) first current sensing means for sensing the magnitude of current in said armature winding;
(ii) second current sensing means for sensing the magnitude of current in said field winding;
(iii) switching means connected in series with each of said armature winding and said field winding;
(iv) a logic control coupled to supply signals to said switching means in response to said accelerator for establishing a current through each of said armature winding and said field winding at a magnitude to cause said motor to accelerate said .[.golf car.]. .Iadd.vehicle .Iaddend.to a speed corresponding to accelerator position, said logic control receiving signals from said first and second current sensing means and being responsive thereto for initiating electrical retarding of said .[.golf car.]. .Iadd.vehicle .Iaddend.when current through said armature winding reverses direction.
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Accused Products
Abstract
A method and apparatus for preventing overspeed of an electrically powered .[.golf car.]. .Iadd.vehicle .Iaddend.having a shunt wound direct current electric motor with an armature winding and a field winding serially connected to respective switching devices and to a source of on-board direct current electric power. The .[.golf car.]. .Iadd.vehicle .Iaddend.includes a control adapted and connected to regulate the current in each of the armature and field windings for controlling speed in response to an operator'"'"'s command. The .[.golf car.]. .Iadd.vehicle .Iaddend.incorporates overspeed detect sensing the magnitude of current in each of the armature winding and the field winding and detecting when the current in the armature winding reverses direction. The magnitude of the armature winding current upon such reversal is compared to a preselected value and an overspeed signal generated when the reverse current magnitude exceeds the preselected value. The field current is then controlled, in response to the overspeed signal, to limit the speed of the .[.golf car.]. .Iadd.vehicle .Iaddend.to inhibit the overspeed condition. Additionally, the voltage at the motor armature winding is monitored during a time period when the motor is in a non-energized condition and a motion signal indicative of motor armature rotation is provided upon detection of a motor armature winding voltage. The motor field winding is energized, in response to the motion signal, with a voltage of a polarity for generating a field current to cause the motor to act as an electric current generator and the current generated by the motor armature is circulated through a plugging diode and into the motor armature for electrically retarding rotation of the motor armature by plug braking.
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Citations
20 Claims
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1. [.A golf car.]. .Iadd.An electrically powered vehicle .Iaddend.having at least one driven wheel .[.and adapted for carrying at least one person and golf equipment on a golf course, the golf car including.]. .Iadd.the vehicle including.Iaddend.:
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a direct current electric drive motor having a separately excited field winding and a separately excited armature winding; a battery for supplying direct current electric power to said drive motor; .[.a foot operated.]. an accelerator for selectively establishing the speed of said vehicle between zero velocity and a preset maximum vehicle speed; control means interconnecting said battery to said drive motor, said control means included; (i) first current sensing means for sensing the magnitude of current in said armature winding; (ii) second current sensing means for sensing the magnitude of current in said field winding; (iii) switching means connected in series with each of said armature winding and said field winding; (iv) a logic control coupled to supply signals to said switching means in response to said accelerator for establishing a current through each of said armature winding and said field winding at a magnitude to cause said motor to accelerate said .[.golf car.]. .Iadd.vehicle .Iaddend.to a speed corresponding to accelerator position, said logic control receiving signals from said first and second current sensing means and being responsive thereto for initiating electrical retarding of said .[.golf car.]. .Iadd.vehicle .Iaddend.when current through said armature winding reverses direction. - View Dependent Claims (2, 3, 4, 5)
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6. A method for preventing overspeed of an electrically powered .[.golf car.]. .Iadd.vehicle.Iaddend., said .[.golf car.]. .Iadd.vehicle .Iaddend.including a shunt wound direct current electric motor having an armature winding and a field winding, each of said armature winding and said field winding being serially connected to respective switching means and to a source of on-board direct current electric power, said .[.golf car.]. .Iadd.vehicle .Iaddend.further including control means adapted and connected to regulate the current in each of said armature and field windings for controlling the speed of said .[.golf car.]. .Iadd.vehicle .Iaddend.in response to an operator'"'"'s command, the .[.golf car.]. .Iadd.vehicle .Iaddend.being subject to overspeed when running downhill, the method comprising the steps of:
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sensing the magnitude of current in each of the armature winding and the field winding; detecting when the current in the armature winding reverses direction; comparing the magnitude of the armature winding current during reversal thereof to a preselected value and providing an overspeed signal when the reverse current magnitude exceeds the preselected value; and controlling the field current, in response to the overspeed signal, to limit the speed of the .[.golf car.]. .Iadd.vehicle .Iaddend.to inhibit the overspeed condition. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method for controlling operation of an electrically powered .[.golf car.]. .Iadd.vehicle.Iaddend., said .[.golf car.]. .Iadd.vehicle .Iaddend.having a shunt wound separately excited electric motor having an armature winding and a field winding and further having an accelerator for selecting a desired speed of operation of the .[.car.]. .Iadd.vehicle.Iaddend., the .[.car.]. .Iadd.vehicle .Iaddend.being operative in one of a motoring, a regenerative electrical braking and an electrical plug braking mode at any one time, the method comprising the steps of:
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responding, by a motor control system, to accelerator position by applying electric power to the motor to affect motion of the .[.golf car.]. .Iadd.vehicle.Iaddend.; detecting an overspeed condition of the .[.golf car.]. .Iadd.vehicle .Iaddend.subsequent to the step of affecting motion thereof and enabling regenerative braking of the .[.car.]. .Iadd.vehicle.Iaddend.; and detecting motion of the .[.car.]. .Iadd.vehicle .Iaddend.prior to actuation of the accelerator and the step of affecting motion thereof and enabling plug braking of the .[.car.]. .Iadd.vehicle.Iaddend.. - View Dependent Claims (20)
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Specification