| 摘要 |
PROBLEM TO BE SOLVED: To detect the individual operation of a power converter by adding a specific order of frequency component to the voltage command value of the power converter, detecting the amplitude value of the specific order of frequency component from a current being outputted from a system, and obtaining the change in the amplitude value. SOLUTION: An n-th order harmonic voltage computing element 13 calculates an n-th order three-phase voltage command value and adds a voltage command value by adders 15d, 15e, and 15f. Then, a PWM computing element 11a outputs a gate pulse based on the voltage command value of the power converter to a power converter 1a. Also, the output of a connection point current detector 2b enables a current amplitude to be calculated by an n-th order harmonic current detector 14a, an individual operation to be detected according to the rapid changes or increase/decrease of the amplitude, and a circuit breaker 19a to be operated. As a result, by deciding the change in system impedance when an individual operation state results according to an n-order current, the individual operation state can be detected and a system can be stopped. |
