Influence of Noise on Multifrequency Signals for the Amplitude and Phase Estimation in Photovoltaic Systems with a DSP Processor

Digital signal processing is used in many areas of technology, science and industry. One of them is analysis of multifrequency signals in PV systems where an estimation method is necessary to run the system. Recently, a new method was developed to estimate frequency, amplitude and phase. It can obtain results very fast (even below one cycle of the tested signal) and it is also very accurate. It is not computationally complex and eliminates the impact of the conjugate component in the spectrum. This paper presents expressions for variances of amplitude and phase estimators taking into account the conjugate component in calculations. Simulation results show that the accuracy of expressions is very high in the tested range of maximum two cycles of distorted by AWGN noise signals taken into calculations. Results were compared with proper Cramér-Rao Bounds in various measurement conditions. Presented expressions allow to calculate error levels of the estimation based on the measurement parameters before starting the estimation process.