Abstract: A model predictive virtual synchronous generator inverter control method considering a frequency-movement direction includes: obtaining a current frequency absolute value based on fundamental frequency of an inverter and a steady-state absolute value based on the fundamental frequency of the inverter; determining a frequency-movement state by comparing the above two absolute values: in a state of deviating from the fundamental frequency or a state of regressing to the fundamental frequency; setting a corresponding prediction output horizon according to the frequency-movement state, and constructing a cost function considering the frequency-movement state; and calculating an optimal virtual power increment value based on the cost function, then calculating an optimal virtual power, inputting the optimal virtual power to a swing equation of a virtual synchronous generator, and performing frequency adjustment according to an output value.

Abstract: A model predictive virtual synchronous generator inverter control method considering a frequency-movement direction includes: obtaining a current frequency absolute value based on fundamental frequency of an inverter and a steady-state absolute value based on the fundamental frequency of the inverter; determining a frequency-movement state by comparing the above two absolute values: in a state of deviating from the fundamental frequency or a state of regressing to the fundamental frequency; setting a corresponding prediction output horizon according to the frequency-movement state, and constructing a cost function considering the frequency-movement state; and calculating an optimal virtual power increment value based on the cost function, then calculating an optimal virtual power, inputting the optimal virtual power to a swing equation of a virtual synchronous generator, and performing frequency adjustment according to an output value.

Abstract: A neutral-point voltage balance control method and system for a three-level converter in a full power factor range. The method includes: using a large, medium, and zero vector modulation method to synthesize a reference voltage vector, and duty cycles of a large vector, a medium vector, and a zero vector; obtaining a voltage difference between two dc-link capacitors of signal acquisition, and the voltage difference as a neutral-point potential of the three-level converter; according to a value relationship between the neutral-point potential of the three-level converter and a specified threshold, selecting a small vector and calculating a duty cycle of the small vector; and updating a duty cycle of each basic vector, and obtaining a switching sequence for controlling a power switch of a three-phase bridge arm. An amplitude of a common-mode voltage of an NPC three-level converter is equal to one sixth of a dc-link voltage.

Abstract: A neutral-point voltage balance control method and system for a three-level converter in a full power factor range. The method includes: using a large, medium, and zero vector modulation method to synthesize a reference voltage vector, and duty cycles of a large vector, a medium vector, and a zero vector; obtaining a voltage difference between two dc-link capacitors of signal acquisition, and the voltage difference as a neutral-point potential of the three-level converter; according to a value relationship between the neutral-point potential of the three-level converter and a specified threshold, selecting a small vector and calculating a duty cycle of the small vector; and updating a duty cycle of each basic vector, and obtaining a switching sequence for controlling a power switch of a three-phase bridge arm. An amplitude of a common-mode voltage of an NPC three-level converter is equal to one sixth of a dc-link voltage.