The Impact of Sampling Aliasing Introduced by Crystal Oscillator Frequency Errors on the Stability of the Droop Control System

The crystal oscillator in the microprocessor is susceptible to errors due to factors such as temperature, shocks, and electrostatic influences. That will lead to errors in the frequency of the generated PWM waves, then the deviations in the switching frequencies can cause sampling aliasing in the inverter, resulting in beat frequency oscillations. In the master-slave control microgrid, the main power source is controlled using droop control, while other distributed energy sources adopt PQ control, beat oscillations will flow into various parts of the droop control system, thus affecting system stability. This results in significant fluctuations or oscillations in the voltage and frequency support provided by the main source, subsequently leading to instability and even uncontrollability of other distributed power sources. In this paper, an investigation and analysis are carried out to examine the effects of varying degrees of inverter switching frequency errors on the stability of the system.