Patent
Inverter system with hysteresis transition between pulse width modulation mode and pure square wave mode of operation
TLDR
A hysteresis circuit is provided within the pulse generating means to guarantee that once the pulse generation has stopped it will not increase again as a result of the aforementioned motor voltage rise.Abstract:
Motor control apparatus for controlling the speed of a motor as a function of a variable frequency square wave and chopping pulses. The chopping pulses are cut off at some value greater than zero pulse width which causes motor voltage to increase in a step manner thus causing a feed forward voltage signal which is related to a DC rectified voltage which cooperates with the square wave production system to increase accordingly. A hysteresis circuit is provided within the pulse generating means to guarantee that once the pulse generation has stopped it will not increase again as a result of the aforementioned motor voltage rise.read more
Citations
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References
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Patent
Adjustable speed A-C motor drive with smooth transition between operational modes and with reduced harmonic distortion
TL;DR: In this paper, a dual d-c level set scheme is proposed to minimize selected harmonics of the alternating voltage and the higher level is varied as a function of the amplitude command signal thereby to vary the amplitude of the fundamental voltage component, and means are provided for smoothly transitioning to a square wave mode of operation as the amplitude signal approaches 1.0 per unit.
Patent
Pulse width modulated inverter adaptive logic
TL;DR: In this paper, an adaptive logic is provided to control conduction of the switch means in the inverter, which is responsive to pulse width, notch width and a maximum or minimum carrier frequency all controlling the change of the ratio of carrier frequency to fundamental frequency.
Patent
Pulse width modulated inverter machine drive
TL;DR: In this article, a control apparatus which regulates inverter switching device conduction by modifying switching signal waveforms transmitted to the inverter to eliminate switching pulses narrower than the minimum inverter switch device pulse width is presented.
Journal ArticleDOI
Technique for pulse dropping in pulse-width modulated inverters
TL;DR: In this paper, it is shown that the traditional method of pulse dropping is unsatisfactory and a new method is proposed which produces much smaller step changes in output voltage, which can produce large current transients in the power circuit and the load.
Patent
Method of controlling pulse width modulated inverter for use in induction motor drive
TL;DR: In this paper, an amplitude ratio of a specific level of a modulating wave and a crest value of a carrier wave is introduced into control of a pulse width modulated inverter.