| Popis: |
Digital control possesses evident advantages and has become a mainstream control of photovoltaic grid connected inverter.The mathematical model and parameter setting of the single phase photovoltaic grid connected inverter with L filter was introduced in the paper.It was analysed on the effect on system stability of digital process from the two aspects which were the zero-order-hold and one-step-delay control. The bode diagram was verified the theoretical analysis on system stability.The conclusions were made that the introduction of digital control reduces the critical stable gain of photovoltaic grid connected inverter system,system stability is varied with sample time, the parameters of L can affect the system stability range,zero-order-hold reduces the stability range and limits the performance improved of digital control system,one-step-delay control on photovoltaic grid connected inverter reduces again the stability range on the basis of the zero-order-hold control. |
