| 摘要 |
PURPOSE: To stabilize the potential of the voltage of a neutral point by controlling the phase, agreeably to the phase data, for a fundamental wave command data, and controlling the amplitude, according to the deviation of the potential of the neutral point, and besides, controlling the amplitude by the data on amplitude range, and generating the sixth harmonic waves, and controlling the phase and amplitude. CONSTITUTION: The controller of a neutral point clamp type inverter controls the phase of the sixth harmonic wave oscillator 1, according to the fundamental wave power factor which changes in the operation state of the inverter, and controls the amplitude of the sixth harmonic waves, according to the deviation of the potential at the neutral point, and adds the sixth harmonic waves of these controlled phase and amplitude to the fundamental wave command value, and gets triangular wave comparison PWM waveform, with the voltage command value of the inverter as frequency and voltage commands. By controlling the phase and amplitude of the sixth harmonic waves when the deviation is going to occur in the potential of the neutral point, a current flows out of the neutral point in the case that the potential of the neutral point goes up too much, and the current flows into the neutral point in the case that it goes down too much, thus the potential of the neutral point is stabilized. |
