US 4,908,553 A · Magnetic regenerative braking system

Abstract

The present invention is a regenerative braking system useful in systems having variable kinetic energy such as vehicles. A DC machine having an independently energized field coil includes a rotor mechanically coupled for rotation at a speed proportional to the velocity of the load. During deceleration the armature is coupled to an inductor and rotational energy provided by the load is converted into magnetic energy stored in the magnetic field of the inductor. To store the energy a short is connected across the inductor, which is preferably operating under superconducting conditions. For acceleration this inductor current is applied to the DC machine to produce a torque for moving the load. The phase reversal required for proper direction of torque is preferably achieved by reversing the direction of field current. The rate of energy transfer and thus the rate of acceleration or deceleration is controlled by controlling the magnitude of the field coil current. A preferred embodiment includes a vehicle battery and motor control for powering the DC machine as the prime mover of the system. A control circuit responsive to vehicle speed, accelerator pedal position, brake pedal position, and the amount of current in the inductor controls switches for proper transfer of energy.

Claims10

Dependent claims

A regenerative braking system adapted for connection to a load having variable kinetic energy, comprising:

a DC machine having a rotor mechanically coupled to the load for rotating at a speed proportional to the velocity of the load, an independently energized field coil and an armature coil;
an inductor;
and
a control circuit connected to said load, said DC machine and said inductor for
decreasing the velocity of the load by energizing said field coil and connecting said inductor across said armature coil, thereby converting kinetic energy of the load into magnetic energy within said inductor via said DC machine,
storing said magnetic energy in said inductor by connecting a short circuit across said inductor, and disconnecting said inductor from across said armature coil, and
increasing the velocity of the load by energizing said field coil, switching said DC machine to an opposite polarity and connecting said inductor across said armature coil, thereby converting the magnetic energy of said inductor into kinetic energy of the load via said DC machine.

4 more elements

A vehicle propulsion system comprising:

a vehicle speed sensor for generating a vehicle speed signal proportional to the speed of motion of the vehicle;
a vehicle battery for storing electrical energy;
an accelerator control for generating an acceleration signal proportional to the rate of acceleration of the vehicle;
a brake control for generating a brake signal proportional to a desired rate of deceleration of the vehicle;
a DC machine having a rotor mechanically coupled to said vehicle for rotation with vehicle motion, a field coil and an armature coil;
an inductor;
a current sensor circuit disposed in proximity to said inductor for generating a current signal indicative of the magnitude of current flowing through said inductor;
a motor control circuit connected to said accelerator control and said DC machine for supplying electric power to said DC machine proportional to said acceleration signal when said motor control circuit is connected to said vehicle battery;
a first controllable switch for controllably either connecting said motor control circuit to said vehicle battery or disconnecting said motor control circuit from said battery;
a second controllable switch for controllably either connecting said armature coil of said DC machine in series with said inductor or disconnecting said armature coil of said DC machine from said inductor;
a third controllable switch connected in shunt with said inductor for controllably either connecting a short circuit across said inductor or disconnecting said short circuit from said inductor;
a control demand circuit connected to said accelerator control and said brake control for generating a control demand signal proportional to the difference between said acceleration signal and said brake signal;
a field coil current driver circuit connected to said control demand circuit and said field coil of said DC machine for supplying current to said field coil corresponding to the magnitude and sign of said control demand signal;
and
a control circuit connected to said vehicle speed sensor, said accelerator control, said brake control, said first, second and third controllable switches, and said current sensor circuit
for controlling said first controllable switch to disconnect said motor control circuit from said battery, said second controllable switch to connect said armature coil of said DC machine in series with said inductor, and said third controllable switch to disconnect said short circuit from said inductor when either (1) said control demand signal indicates a desired net acceleration demand and said current signal indicates the presence of a nonzero current through said inductor, or (2) said control demand signal indicates a net braking demand, said vehicle speed signal indicates a vehicle speed greater than zero and said current signal indicates an inductor current less than a predetermined amount,
for controlling said first controllable switch to disconnect said motor control circuit from said vehicle battery, said second controllable switch to disconnect said armature coil of said DC machine from said inductor, and said third controllable switch to connect said short circuit across said inductor when either (1) said control demand signal indicates a net braking demand, said vehicle speed signal indicates a vehicle speed greater than zero and said current signal indicates an inductor current greater than or equal to said predetermined amount, (2) said control demand signal indicates a net braking demand and said vehicle speed signal indicates a vehicle speed equal to zero, or (3) said control demand signal indicates a zero net demand, and
for controlling said first controllable switch to connect said motor control circuit to said vehicle battery, said second controllable switch to disconnect said armature coil of said DC machine from said inductor, and said third controllable switch to disconnect said short circuit across said inductor when said control demand signal indicates a net acceleration demand and said current signal indicates zero current through said inductor.

15 more elements

Dependencies are inferred from the claim text.

Magnetic regenerative braking system

Life of this patent

Magnetic regenerative braking system

Life of this patent

Abstract

Claims10