CURRENT SIGNAL GENERATOR AND METHOD OF IMPLEMENTING SUCH A GENERATOR
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Abstract
A generator for providing regulated current signals, to terminals of a load includes: a plurality of secondary stages, including a direct voltage source insulated from those of other stages, connected in series between the midpoint of the second half-bridge of each secondary stage and the midpoint of the first half-bridge of the next secondary stage, the load terminals being respectively connected to the midpoint of the first half-bridge of a first secondary stage, and to the midpoint of the second half-bridge of a last secondary stage; and a control circuit capable of: selecting a group of secondary active stages, and at least one regulating stage; simultaneously controlling each active stage, except the regulating stage, at the frequency of the current slots; controlling the regulating stage according to a frequency higher than the previous one; and controlling the switches of the non-selected secondary stages to insulate their voltage source.
27 Citations
24 Claims
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1-12. -12. (canceled)
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13. Generator of current signals, suitable to provide signals of regulated current of alternating polarity under high voltage to the terminals of a load (7), said generator comprising:
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a plurality of circuits, so-called secondary stages (20), each secondary stage (20) including at least one source (21) of DC voltage isolated from the voltage sources (21) of the other secondary stages, and a switching circuit (22) comprising four switches (Q1-Q4) arranged in first (Q1, Q2) and second (Q3, Q4) half-bridges each formed of two switches connected in series between the positive pole and the negative pole of the voltage source, the secondary stages (20) being interconnected in such a way that the midpoint of the second half-bridge (Q3, Q4) of each secondary stage is linked to the midpoint of the first half-bridge (Q1, Q2) of the following secondary stage, the terminals (5,8) of the load (7) being respectively linked to the midpoint of the first half-bridge of a first secondary stage and to the midpoint of the second half-bridge of a last secondary stage, and a control circuit (15), wherein said current signals are gating pulses of current and wherein said control circuit (15) is suitable to; select a group of secondary stages (20), so-called active stages, depending on a set point (Ic) of a current flowing in the load (7), select from said active stages at least one stage, the so-called regulation stage, control simultaneously the switches (Q1-Q4) of each active stage, with the exception of the regulation stage, at the frequency (T1, T3) of, and synchronously with, the gating pulses of current, so as to place the voltage sources of these stages in series, control the switches (Q1-Q4) of said regulation stage in accordance with a frequency (TREG) higher than the preceding frequency, with a control duty cycle that is suitable to regulate the current flowing in the load to the set point (Ic), control the switches (Q1-Q4) of the non-selected secondary stages, in order to isolate their voltage source (21). - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. Process for generation of current signals, suitable to provide signals of regulated current of alternating polarity under high voltage to the terminals (5,8) of a load (7), in which:
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a generator including a plurality of secondary stages (20) each including a source (21) of DC voltage isolated from the voltage sources of the other secondary stages, and a switching circuit (22) comprising four switches (Q1-Q4) arranged in first (Q1, Q2) and second (Q3, Q4) half-bridges each formed of two switches connected in series between the positive pole and the negative pole of the voltage source are used, the secondary stages being interconnected in such a way that the midpoint of the second half-bridge of each secondary stage is linked to the midpoint of the first half-bridge of the following secondary stage, the terminals (5,8) of the load (7) being respectively linked to the midpoint of the first half-bridge of a first secondary stage and to the midpoint of the second half-bridge of a last secondary stage, wherein; current signals in the form of gating pulses are voluntarily generated, a group of secondary stages (20), so-called active stages, is selected, depending on a set point (Ic) of a current flowing in the load (7), from said active stages at least one stage, the so-called regulation stage, is selected, simultaneously the switches (Q1-Q4) of each active stage, with the exception of the regulation stage, are controlled at the frequency (T1, T3) of, and synchronously with, the gating pulses of current, so as to place the voltage sources of these stages in series, the switches (Q1-Q4) of said regulation stage are controlled in accordance with a frequency (TREG) higher than the preceding frequency, with a control duty cycle that is suitable to regulate the current flowing in the load to the set point (Ic), the switches (Q1-Q4) of the non-selected secondary stages are controlled, in order to isolate their voltage source (21).
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Specification