Controller Design for Synchronizing Distributed Generation Systems with the Phase Locked Loop (PLL)
S. Z. Moussavi1, P. Amiri2, S. A. Hoseini3
1Seyyed Zynolabedin Mousavi, Shahid Rajaee Teacher Training University. Babaee Highway, Lavizan, Electrical And Computer Engineering Department, Laboratory Of Microelectronic, Tehran, Iran.
2Parviz Amiri, Shahid Rajaee Teacher Training University. Babaee Highway, Lavizan, Electrical and Computer engineering Department, Laboratory Of Microelectronic, Tehran, Iran.
3Seyyed Ahmad Hoseini, Shahid Rajaee teacher Training University. Babaee Highway, Lavizan, Electrical And Computer engineering Department, Laboratory Of Microelectronic, Tehran, Iran.
Manuscript received on September 22, 2012. | Revised Manuscript received on October 12, 2012. | Manuscript published on October 30, 2012. | PP: 122-128 | Volume-2 Issue-1, October 2012. | Retrieval Number: A0746102112/2012©BEIESP
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Abstract: In this paper a fuel cell power plant design using phase locked loop method for paralleling a fuel cell with the global network is described. Despite the fact that synchronous systems for scattering generation sources like generators have been used in Iran’s plants, but there has been made fewer efforts in the case of plants based on fuel cell. In this paper an approach is presented for synchronization based on PLL that can reduce the response time to less than 2 seconds and time difference becomes zero in less than 3 seconds. Using the relay auto tuning algorithm in the closed loop system, the frequency fluctuations become less than 0.05% at the output. As in this approach, tuning is based on the DC voltage level, the induction property that makes the PID controller be unstable is reduced and we will have a very stable output wave. This is the main advantage of this controller. Presented control structure is made up of three loops, whichwe will reached frequency to reference frequency by use of first loop and in the next loop we do it’s phasecontrol whit take an integration of frequency, and in the frequencies difference less than 1 Hz. Presented control structure is made up of three loops. Using first loop, the frequency is reached near the reference value and in the next loop the phase is controlled by integration of the frequency, and in the frequency differences less than 1 Hz, the third loops does control frequency in independent way from the phase. Another advantage of this method is that the circuit remains in phase locked state when the phase has been synchronized, and there is no need to consider the time of connection to the network, and finally the output fluctuation is brought into zero. In this paper, it is also built an empirical example of digital synchronizer which is efficient in synchronizing distributed generation systems with the phase locked loop and will be described in detail in continuation.
Keywords: Phase locked loop, synchronizer, parallel and fuel cell.