Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
89 words
Control circuit for an inverter with a variable voltage and output frequency, in which the variation of amplitude of the output voltage is provided by a chopper of the supply voltage, including means of controlling the frequency of the chopper and the output frequency, characterized by the fact that the frequency of the chopper is a multiple of the inverter frequency, the means for controlling the frequency of the chopper being set so as to modify automatically said multiple when the frequency of the chopper leaves a predetermined range.
Claim 2
Dependent Claim
89 words
Control circuit for an inverter with a variable voltage and output frequency, in which the variation of amplitude of the output voltage is provided by a chopper of the supply voltage, including means of controlling the frequency of the chopper and the output frequency, characterized by the fact that the frequency of the chopper is a multiple of the inverter frequency, the means for controlling the frequency of the chopper being set so as to modify automatically said multiple when the frequency of the chopper leaves a predetermined range.
Claim 3
Dependent Claim
109 words
Circuit according to claim 1, characterized by the fact that it includes means for integrating a voltage of the inverter so as to obtain a signal which is an image of the variation of the flux in a motor supplied by the inverter, the output voltage of the inverter being decreased each time this signal reaches a maximum value corresponding to the desired variation of flux, the integrated signal then being reset to zero, the output voltage being periodically increased to a multiple of the frequency of the inverter, means being provided for making a variation of flux inversely proportional to the selected multiple corresponding to said maximum value.
Claim 4
Dependent Claim
54 words
Circuit according to claim 1, characterized by the fact that the control of the frequency of the inverter is obtained from a variable-frequency oscillator and means for dividing the oscillator frequency by two, the output frequencies of the oscillator and of the dividing means being selected as the chopper frequency of the supply voltage.
Claim 5
Dependent Claim
59 words
Circuit according to claim 2, in which said maximum value of the integrated signal is constant and in which current is supplied to said integrating means via a modifiable resistance, the value of which is inversely proportional to said chosen multiple, and including means for supplying to said modifiable resistance a voltage proportional to the voltage to be integrated.
Claim 6
Dependent Claim
28 words
CircUit according to claim 1, comprising a variable-frequency oscillator and means for providing a minimal frequency, and flip-flop means for selecting successive frequencies to periodically retrigger the chopper.
Claim 7
Dependent Claim
52 words
Circuit according to claim 5, in which said means for modifying said multiple includes a circuit which delivers a signal when the period of the pulses of the chopper is smaller than a minimal period or greater than a maximum period, said maximum period being slightly greater than twice said minimal period.
Claim 8
Dependent Claim
53 words
Circuit according to claim 1, comprising means sensitive to the amplitude of the negative peaks of the d.c. current supplying the inverter after each switching of the phases of the inverter for acting on the inverter output voltage in a manner to reduce said voltage when the amplitude of said negative peaks increases.
Claim 9
Dependent Claim
63 words
Circuit according to claim 1, comprising means sensitive to the amplitude of the negative peaks of the d.c. current supplying the inverter after each switching of the phases of the inverter for acting on the switching frequency of the phases of the inverter to momentarily modify the frequency thereof, an increase in the amplitude of said negative peaks momentarily increasing said switching frequency.