| 摘要 |
PURPOSE:To reduce the cost of a device by transmitting frequency and phase data over a sub-processor from a main processor in order to generate sine waves and changing the number of samples read from sine-wave sampling data and the position of sampling by the sub-processor. CONSTITUTION:A main processor 1 conducts the arithmetic operation of slip frequency and the arithmetic operation of vector control from the revolution signal of an induction motor and a speed pattern signal, torque is obtained, and the frequency of an inverter output, phase and primary current data are acquired. A sub-processor 2 obtains sine-wave sampling data coinciding with frequency and phase data transmitted from the main processor 1. D/A converters 41, 42 each convert said sampling data into analog signals, and change the amplitude of sine-wave analog signals, using primary current data transmitted from the main processor 1 as conversion gains in the conversion. These data are employed as pulse-width modulated gate pulses, thus controlling each switching element.
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