Control method for a three-phase self-excited inverter
AssigneeBrown, Boveri & Cie AG
InventorsLudwig Abraham, Armando Moschetti
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Abstract
A control method for a three-phase self-excited inverter which is fed from a dc voltage source and in which the fundamental oscillation of the output voltage is adjustable in frequency and amplitude, in particular by the subharmonic method, and wherein the pulsing or timing is always done in only one of three phases (R, S or T) such that 60.degree.-wide pulse regions are arranged symmetric to the maximum and minimum of the fundamental voltage oscillation of each phase (R, S or T) and overlap each fundamental voltage oscillation.
Claims2
In a control method for a three-phase self-excited inverter which is fed from a DC voltage source and in which the fundamental oscillation of the output voltage is adjustable in frequency and amplitude, in particular by the subharmonic method, the improvement comprising:
- generating three phased series of triangular waveform signals of the same amplitude and having repetition frequencies bearing predetermined relationships;
- generating an input command signal having an amplitude variable between predetermined limits;
- level comparing selected of the triangular waveform signals with said input command signal;
- generating sequentially non-overlapping respective series of gate pulse signals for initiating switching of an inverter coupled to a respective phase (R, S or T), the gate pulse signals for a respective phase being generated only in two 60.degree. (electrical)-wide operating pulse regions arranged symmetric to the maximum and minimum of the fundamental voltage oscillation of said respective phase (R, S or T) and such that said 60.degree. (electrical)-wide pulse regions overlap the fundamental voltage oscillation of each respective phase.
Dependencies are inferred from the claim text.