| 摘要 |
PURPOSE:To enable good operational characteristic to be obtained in the full operation range of an inverter, by setting a means for synchronizing a reference waveform and a triangular wave carrier waveform with each other, on the output of constant frequency. CONSTITUTION:Binary data and the pulse trains of the constant frequency of a reference generator 1 are multiplied by each other with a proportional multiplication unit 2, and the pulse trains of the output are counted by a phase unit 3a. From the phase output unit 3a, the output of voltage in proportion to residual phase for output for reference waveform generated hereafter is generated, and by a subtractor 4, from the voltage, the output of a carrier frequency command unit 8a is subtracted. By the subtractor 4 and a polarity discriminator 5, the positive or the negative of (output remainder phase quantity)-(2 X triangular wave carrier cycle) is discriminated. Only when the output of the polarity discriminator 5 is 1 on constant frequency output, then voltage in proportion to the output remainder phase for output generated from the phase output unit 3a is subtracted from voltage for carrier frequency command for output generated from the carrier frequency command unit 8a.
|
