Analysis and modeling of novel brushless exciter based on hybrid excitation topology
The exciter is a key component of the synchronous generator system with self-excited initiation. Based on the topology of hybrid excitation, this paper proposes a novel brushless exciter, which is suitable for an isolated power system. The parameters of the exciter are calculated by the numerical method based on finite element model, and the state space model is established. The experimental researches are carried out on a 3 kW prototype.
Synchronous Generator Output Voltage Real-Time Feedback Control via $H_\infty$ Strategy
A new approach on synchronous generator (SG) output voltage control is presented. The originality of such a strategy is based on the excitation structure that integrates a permanent-magnet generator combined with a modern control method: the H infin. The main motivation of this paper is the debatable results obtained with the classical excitation structure controlled by a traditional PID controller. The SG model as well as the control strategy will be presented. The implementation in real time domain and a comparison with the classical structure will allow us to prove the efficiency of the proposed structure compared to the classical one as regards the reference tracking and signal quality.
DC vacuum circuit-breaker
The results of switching tests of a DC vacuum circuit-breaker designed for rated voltage 3.3 kV and rated current 3000A are presented. The circuit-breaker is intended for current interruption in the networks with fault currents up to 30 kA. To interrupt the direct current, the authors used a method of artificial current transition through zero in the electrical arc between the vacuum interrupter (VI) contacts by means of discharging a preliminary charged capacitor with countercurrent having the direction reverse to the one of the interrupted current. The countercurrent circuit was connected with the use of a triggered vacuum switch (TVS). The contacts in the VI were opened with an electromagnetic repulsion drive activated in the result of the preliminary charged capacitor discharge. The drive circuit was also controlled with the TVS. The contact opening time was 3 ms. The TVS switch-on time did not exceed several microseconds. Three test cycles were carried out for the cases of the current interruption in the mode similar to the normal one, in the fault current mode and in the low current mode. The tests proved that the circuit-breaker ensured safe current interruption in all those modes.