Method and apparatus for propelling and retarding off-road haulers

In a system for propelling an off-road hauler of the type in which an internal combustion engine drives an AC generator to produce AC current, an AC grid electrically connected to said AC generator distributes said AC current, a first thyristor-type converter electrically connected to said AC grid and a DC electrical wheel motor receives AC power from the AC power distribution grid and delivers DC power to said DC electric wheel motor which, in turn, delivers motive power to a drive wheel for said hauler, the improvement comprising:

• line power connection means on said hauler for selective electric connection to DC line power from a source external to said hauler;
• and
• a second thyristor-type converter electrically connected to said line power connection means and said AC grid, said second thyristor-type converter comprising means for receiving DC power from said line power connection means and delivering AC power to said AC grid;
• whereby electrical power from said source external to said hauler may be used to replace AC power supplied by said AC generator, to thereby reduce fuel consumption by said internal combustion engine, without electrically disconnecting said AC generator from said AC grid and without using electrical switching apparatus for switching between AC power supplied by said AC generator and DC power supplied from said line power source external to said hauler.

A system selectively operable in propel and retarding modes for, selectively, propelling and retarding an off-road hauler, said system comprising:

• an internal combustion engine;
• AC generator means mechanically connected to said engine and adapted, when said system is operated in said propel mode, to be powered by said engine to generate AC electric power and adapted, when said system is operated in said retarding mode, to act as an AC electric motor and to deliver power to said engine;
• AC power distribution means electrically connected to said AC generator means and adapted, when said system is operated in said propel mode, to distribute AC electric power generated by said generator means and adapted, when said system is operated in said retarding mode, to deliver AC electric power to said generator means;
• voltage regulator means electrically connected to said AC power distribution means, said voltage regulator means comprising means for regulating the voltage of said AC electric power;
• DC wheel motor means on said hauler and adapted, when said system is operated in said propel mode, to deliver propelling torque to a drive wheel of said hauler and adapted, when said system is operated in said retarding mode, to act as a DC generator, receiving motive power from said drive wheel of said hauler and generating DC electric power to thereby exert retarding torque on said drive wheel;
• armature thyristor converter means electrically connected to said AC power distribution means and said DC wheel motor means and adapted, when said system is operated in said propel mode, to receive AC electric power from said AC power distribution means and to deliver DC electric power to said DC wheel motor means and adapted, when said system is operated in said retarding mode, to receive DC power generated by said DC wheel motor means and to deliver AC electric power to said AC power distribution means;
• field current generating means associated with said DC wheel motor means, said field current generating means comprising means for generating a DC current field for said DC wheel motor means;
• field current thyristor converter means electrically connected to said AC power distribution means and said field current generating means, said field current thyristor converter means comprising means for receiving AC power from said AC power distribution means and supplying DC power to said field current generating means;
• means associated with said DC wheel motor means for selectively causing said DC wheel motor means to act as a motor when said system is operated in said propel mode and to act as a DC generator when said system is operated in said retarding mode;
• retarding resistor means adapted, when said system is operated in said retarding mode, to consume electric power generated by said DC electric wheel motor means;
• retarding resistor thyristor converter means electrically connected to said AC power distribution means and said retarding resistor means, said retarding resistor thyristor converter means comprising means for receiving AC electric power from said AC power distribution means and supplying DC electric power to said retarding resistor means;
• and
• control means electrically connected to said voltage regulator means, armature thyristor converter means, field current thyristor converter means and retarding resistor thyristor converter means, said control means comprising means for controlling the operation of said voltage regulator means, armature thyristor converter means, field current thyristor converter means and retarding resistor thyristor converter means to thereby control the direction and amount of propelling and retarding torque exerted by said DC wheel motor means;
• whereby, when said system is operated in said retarding mode, electric power generated by said DC wheel motor means may be used first to reduce the power requirements for said internal combustion engine, with excess electric power generated by said DC electric wheel motor means being supplied to said retarding resistor means.

A system for selectively propelling and retarding an off-road hauler, said system comprising:

• an internal combustion engine;
• an AC generator mechanically connected to said engine;
• an AC power distribution grid electrically connected to said AC generator;
• a voltage regulator electrically connected to said AC power distribution grid for regulating the voltage of AC electric power in said AC power distribution grid;
• an armature converter electrically connected to said AC power distribution grid;
• a DC electric wheel motor electrically connected to said armature thyristor converter;
• a drive wheel for said off-road hauler mechanically connected to said DC electric wheel motor;
• an electrical coil associated with said DC electric wheel motor for generating a DC current field for said DC electric wheel motor;
• a field current thyristor converter electrically connected to said coil and to said AC power distribution grid;
• a plurality of retarding resistors for dissipating excess electrical power generated in said system;
• a retarding resistor thyristor converter electrically connected to said plurality of retarding resistors and electrically connected to said AC power distribution grid;
• and
• a controller for controlling the operation of said voltage regulator, armature thyristor converter, field current thyristor converter and retarding resistor converters;
• whereby said system may be operated in a propel mode in which said internal combustion engine drives said AC generator to produce AC power for supply to said AC power distribution grid, said armature thyristor converter converts AC power to DC power for said DC electric wheel motor, and said DC wheel motor exerts a desired propelling torque on said drive wheel;
• and whereby said system also may be operated in a retarding mode in which the direction of current in one of said DC current field and said DC electric wheel motor is reversed in polarity, said drive wheel of said hauler powers said DC electric wheel motor, causing said DC electric wheel motor to generate DC electrical power which is converted by said armature thyristor converter to AC electrical power and supplied to said AC power distribution grid, said AC generator is powered by AC power from said AC power distribution grid, causing said AC generator to operate as an AC motor, driving said internal combustion engine, so as to reduce the fuel requirements for said engine and excess AC electrical power generated by said DC electric wheel motor is converted to DC electrical power by said retarding thyristor converter and is consumed by said retarding resistors and dissipated as heat.

An electrical propulsion and distribution system for a vehicle, comprising:

• an AC grid;
• an AC generator coupled to said AC grid, and adapted to be coupled to an internal combustion engine;
• a trolley converer, having DC terminals, having a control input, and having AC terminals coupled to said AC grid, for inverting DC power applied to said DC terminals and applying the inverted DC power to said AC grid responsive to control signals received at the control input of said trolley converter;
• a DC motor, having a field coil and an armature;
• a field converter for applying power from said AC grid to the field coil of a DC motor responsive to signals received at a control input;
• an armature converter for applying power from said AC grid to the armature of a DC motor responsive to signals received at a control input;
• and
• a controller, having outputs coupled to the control input of said trolley converter, to the control input of said field converter, and to the control input of said armature converter, said controller also having an input for sensing DC power applied to said DC terminals of said trolley converter, said controller for controlling said field converter and said armature converter to apply power from said AC grid to said field coil and armature, respectively, and for gating said trolley converter in such a manner to apply the inverted DC power to said AC grid simultaneously with said AC generator applying AC power to said AC grid.

An electrical propulsion and distribution system for a vehicle, comprising:

• an AC grid;
• an AC generator coupled to said AC grid, and adapted to be coupled to an internal combustion engine;
• a trolley converter, having DC terminals, having a control input, and having AC terminals coupled to said AC grid, for inverting DC power applied to said DC terminals and applying the inverted DC power to said AC grid responsive to control signals received at the control input of said trolley converter;
• a DC motor, having a field coil and an armature;
• a field converter for applying power from said AC grid to the field coil of a DC motor responsive to signals received at a control input;
• an armature converter for applying power from said AC grid to the armature of a DC motor responsive to signals received at a control input;
• a retard load connected across said DC terminals;
• and
• a controller, having output coupled to the control input of said trolley converter, to the control input of said field converter, and to the control input of said armature converter, said controller also having an input for sensing DC power applied to said DC terminals of said trolley converter, said controller for controlling said field converter and said armature converter to apply power from said AC grid to said field coil and armature, respectively, and for gating said trolley converter in such a manner to apply the inverted DC power to said AC grid;
• wherein said controller, in a retard mode, is also for controlling said field coil converter to apply reversed current to the field coil so that said armature converter applies power to said AC grid in such a manner that said AC grid powers said AC generator as a synchronous motor, and for controlling said trolley converter in such a manner that said retard load receives power from said AC grid.

An electrical propulsion and distribution system for a vehicle, comprising:

• an AC grid;
• an AC generator coupled to said AC grid, and adapted to be coupled to an internal combustion engine;
• a trolley converter, having DC terminals, having a control input, and having AC terminals coupled to said AC grid, for inverting DC power applied to said DC terminals and applying the inverted DC power to said AC grid responsive to control signals received at the control input of said trolley converter;
• a DC motor, having a field coil and an armature;
• a field converter for applying power from said AC grid to the field coil of a DC motor responsive to signals received at a control input;
• an armature converter for applying power from said AC grid to the armature of a DC motor responsive to signals received at a control input;
• a retard load connected across said DC terminals;
• and
• a controller, having outputs coupled to the control input of said trolley converter, to the control input of said field converter, and to the control input of said armature converter, said controller also having an input for sensing DC power applied to said DC terminals of said trolley converter, said controller for controlling said field converter and said armature converter to apply power from said AC grid to said field coil and armature, respectively, and for gating said trolley converter in such a manner to apply the inverted DC power to said AC grid;
• wherein said controller, in a retard mode, is also for controlling said armature converter to apply reversed current to the armature and to apply power to said AC grid in such a manner that said AC grid powers said AC generator as a synchronous motor, and for controlling said trolley converter in such a manner that said retard load receives power from said AC grid.