| 主权项 |
1. A static synchronous compensator comprising:
a single-phase voltage AC-DC conversion circuit having an internal electromotive force and an internal equivalent impedance when viewed from an AC terminal and converting between a single-phase AC power from a single-phase AC power system connected to the AC terminal and a DC power according to the pulse width of a gate signal generated based on a PWM command; a voltage command circuit outputting a first axis voltage command acting as an amplitude target value of a single-phase AC voltage of the AC terminal, set with a DC voltage command value higher than the peak value of the single-phase AC voltage, detecting the DC voltage converted by the single-phase voltage AC-DC conversion circuit, and outputting the second axis voltage command by calculating the difference between the DC voltage command value and the DC voltage detection value; a phase difference generation circuit having a phase-delayed single-phase AC current generator for delaying the phase of a single-phase AC voltage of the AC terminal and generating a delayed single-phase AC current and generating a voltage corresponding to the phase difference between the single-phase AC voltage of the AC terminal and the internal electromotive force of the single-phase voltage AC-DC conversion circuit based on the delayed single-phase AC current; a upper voltage control circuit outputting a voltage command signal generated so that the amplitude of the single-phase AC voltage of the AC terminal approaches the first axis voltage command and a frequency command signal generated so that a voltage corresponding to the phase difference from the phase difference generation circuit approaches the second axis voltage command based on the first axis voltage command and the second axis voltage command from the voltage command circuit, the voltage corresponding to the phase difference from the phase difference generation circuit, and the single-phase AC voltage of the AC terminal; a frequency control circuit set with a reference frequency acting as a reference of the frequency of the single-phase AC current in the AC terminal, determining the electric angle of the internal electromotive force of the single-phase voltage AC-DC conversion circuit based on the reference frequency, the frequency command signal from the upper voltage control circuit, and the voltage corresponding to the phase difference generated by the phase difference generation circuit, and generating a generated electric angle; and a lower voltage control circuit set with a reference voltage acting as a reference of the voltage amplitude of the single-phase AC current in the AC terminal, using the value obtained by adding the voltage command signal from the upper voltage control circuit to the value, which is obtained by multiplying the signal based on the electric angle from the frequency control circuit and the reference voltage, as an internal electromotive force and outputting the difference between the internal electromotive force and the single-phase AC voltage as the PWM command. |
