Sequenced pulse width modulation method and apparatus for controlling and powering a plurality of direct current motors
AssigneeRailpower Technologies Corp.
InventorsFrank Wegner Donnelly, Brian Ward Gulayets
Life of this patent
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Abstract
A control system for individually controlling power from a single voltage source to a plurality of motors is described. A chopper circuit, in conjunction with the control system, generates drive-pulses, which operates the IGBT switching devices to sequentially provide pulses to each motor.
Claims54
A method of controlling power provided from a direct current power storage source to a plurality of direct current traction motors, comprising:
- (a) determining the power requirement for each motor at each of a number of successive time intervals;
- (b) determining the necessary effective amplitude and pulse width of a power pulse to achieve the desired power for each motor;
- and
- (c) sequentially pulsing power to each said motor for a duration necessary to achieve said power requirement at said time interval, wherein, for each motor, the frequency of pulses is maintained at least substantially constant and wherein the pulse width is varied depending upon the revolutions per minute of the respective traction motor.
An apparatus for controlling power provided from a direct current power storage source to a plurality of direct current traction motors, comprising:
- (a) a controller operable to determine the power requirement for each motor at each of a number of successive time intervals and determine the necessary amplitude and pulse width of a power pulse to achieve the desired power for each motor;
- and
- (b) a sequencer operable to sequentially pulse power to each said motor for a duration necessary to achieve said power requirement at said time interval, wherein, for each motor, the frequency of pulses is maintained at least substantially constant and wherein the pulse width is varied depending upon the revolutions per minute of the respective action motor.
A method of controlling power provided from a direct current power source to a plurality of direct current traction motors, comprising:
- (a) determining the power requirement for each motor at each of a number of successive time intervals;
- (b) determining the necessary effective amplitude and pulse width of a power pulse to achieve the desired power for each motor;
- and
- (c) sequentially pulsing power to each said motor for a duration necessary to achieve said power requirement at said time interval, wherein, when the revolutions per minute (RPM) of each of the traction motors is below an intermediate RPM threshold, the pulses provided to the direct current traction motors are temporally non-overlapping and, when the RPM of each of the traction motors is above the intermediate RPM threshold, the pulses provided to the direct current traction motors are temporally at least partially overlapping.
An apparatus for controlling power provided from a direct current power source to a plurality of direct current traction motors, comprising:
- (a) a controller operable to determine the power requirement for each motor at each of a number of successive time intervals and determine the necessary amplitude and pulse width of a power pulse to achieve the desired power for each motor;
- and
- (b) a sequencer operable to sequentially pulse power to each said motor for a duration necessary to achieve said power requirement at said time interval, wherein, when the revolutions per minute (RPM) of each of the traction motors is below an intermediate RPM threshold, the pulses provided to the direct current traction motors are temporally overlapping and, when the RPM of each of be traction motors is above the intermediate RPM threshold, the pulses provided to the direct current traction motors are temporally at least partially overlapping.
A method of controlling power provided from a direct current power source to a plurality of direct current traction motors, comprising:
- (a) determining that at least a first traction motor is experiencing wheel slip while each of the remaining traction motors are not experiencing wheel slip;
- (b) in response to the determining step, terminating power to the at least a first traction motor while continuing to provide power pulses to the remaining traction motors;
- and
- (c) sequentially pulsing power to each said traction motor for a duration sufficient to achieve a selected power requirement for each traction motor during a selected time interval, wherein, for each motor, the frequency of pulses is maintained at least substantially constant and wherein the pulse width is varied depending upon the revolutions per minute of the respective traction motor.
An apparatus for controlling power provided from a direct current power source to a plurality of direct current traction motors, comprising:
- a controller operable to (a) determine that at least a first traction motor is experiencing wheel slip while each of the remaining traction motors are not experiencing wheel slip and (b), in response to the wheel slip determination, terminate power to the at least a first traction motor while continuing to provide power pulses to the remaining traction motor;
- and further comprising a sequencer operable to sequential pulse power to each said motor for a duration necessary to achieve a selected power requirement at a selected time interval, wherein, for each motor, the frequency of pulses is maintained at least substantially constant and wherein the pulse width is varied depending upon the revolutions per minute of the respective traction motor.
Dependencies are inferred from the claim text.