| 摘要 |
Variable-frequency control method for electric drives by means of varying the output voltage or current, and of varying the inverter frequency, whereas the inverter frequency is worked out in the PI regulator depending on the differential voltage fed from the frequency regulator or depending on another superordinated parameter, and from the signal proportional to the active component of the machine's magnetic flux, or depending on a signal being proportional to the phase angle between the machine's flux and the inverter current, and the inverter frequency is also worked out by limiting the output signal from the frequency controller, or by limiting another superordinated parameter by a signal worked out previously in the limit calculation circuit, whereas that signal is the machine's real flux signal or the sum of the real flux signal and of the flux error signal, or the sum of the constant signal and of the real flux signal, characterized in that the acceleration limit circuit (15) controls the absolute value of the limit signal that was worked out by a known method in the limit circuit (4), or the acceleration limit circuit (15) controls another superordinated parameter, and further, if the controlled signal's absolute value increases, the rise time of that signal also increases so that the time -constant of the signal received at the acceleration limit block (15) output is preferably equal to the time -constant of the machine's magnetic flux increase, whereas that machine is supplied from the inverter, and further, the signal formed so is used for limiting the frequency controller (10) output signal of for limiting another superordinated parameter.<IMAGE>
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