Chopper control system
AssigneeHitachi, Ltd.
InventorTaturo Horie
Life of this patent
Estimating the term…
Abstract
A system for controlling a thyristor chopper used for the speed control of a d.c. motor driving an electric car, in which means are provided for generating turn-on pulses and turn-off pulses at the maximum chopping frequency of the chopper, dividing the frequency of the turn-on pulses and turn-off pulses stepwise in response to the application of chopping frequency instruction signals, and applying these frequency-divided turn-on and turn-off pulses to the chopper for controlling the chopper, so that the motor can be smoothly controlled by the chopper whose chopping frequency varies stepwise from a low to a high valve with conductive rate-control.
Claims5
A system for controlling a chopper which conducts in response to the application of a train of turn-on pulses and is rendered non-conducting in response to the application of a train of turn-off pulses, comprising a frequency oscillator for generating a train of pulses determining the maximum chopping frequency of said chopper and providing said turn-off pulses, means for generating said turn-on pulses in synchronism with said turn-off pulses generated by said frequency oscillator in such a relationship that said turn-on pulses alternate with said turn-off pulses, means for generating instruction signals consisting of a plurality of turn-on pulse instruction signals indicating the frequency of the turn-on pulse to be applied to the chopper and a plurality of turn-off pulse instruction signals indicating the frequency of the turn-off pulse to be applied to the chopper, turn-off pulse selecting means for selectively applying the pulses of the turn-off pulse train generated by said frequency oscillator to said chopper depending on the applied turn-off pulse instruction signal, and turn-on pulse selecting means for selectively applying the pulses of the turn-on pulse train generated by said turn-on pulse generating means to said chopper depending on the applied turn-on pulse instruction signal.
Dependencies are inferred from the claim text.