| 摘要 |
A control circuit for a DC inverter for an induction motor comprises: circuitry to produce a control waveform characterized by a sequence of pulse groups wherein the durations of the pulse groups increase with time, and wherein the widths of the pulses within each group increase with time, the circuitry supplying the waveform to the inverter. The circuits typically includes: (i) a first oscillator having a sawtooth output, (ii) a ramp generator having a voltage output which changes with time, (iii) a first comparator operatively connected with and responsive to the first oscillator and ramp generator outputs to produce an output characterized by a duty cycle which increases with time, and (iv) a second oscillator responsive to the comparator output to produce an output having a frequency which increases with time.
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