Electrically driven distillation system with variable dynamic load and a distillation method

An inverter control method, characterized in that the method comprises:

• when the inverter is in a virtual synchronous generator (VSG) control mode, simulate frequency regulation characteristics of a VSG by a speed regulator to determine a first relational expression of active power-frequency droop characteristics of the VSG and a second relational expression of rotor angular velocity of the VSG and a virtual damping coefficient and virtual inertia of the inverter;
• determine a frequency control relationship of the inverter in a grid-connected state according to the first relational expression and the second relational expression;
• adjust a virtual electromotive force of the VSG, thereby adjusting output of reactive power of the inverter, and determine a third relational expression between the virtual electromotive force of the VSG in the reactive state and output voltage of the inverter;
• construct a voltage-current dual closed-loop control structure of the inverter in the VSG control mode, and determine a current reference value and a voltage reference value of the virtual synchronous generator under a dq axis by the frequency control equation and the third relational expression;
• wherein determining the current reference value and the voltage reference value of the virtual synchronous generator under the dq axis by the frequency control equation and the third relational expression comprises:
• determining the output voltage amplitude and phase angle of the virtual synchronous generator by the frequency control equation and the third relational expression;
• wherein,
• the output voltage amplitude and phase angle are converted to the dq axis, and feedback is calculated with the actual output voltage value under the inverter VSG control mode under the dq axis;
• the result of feedback calculation is controlled by proportional integral to determine the dq axis reference current;
• the reference current is feedback-calculated with the actual output current component of the inverter VSG control mode in the dq axis, and
• the result of the feedback calculation is controlled by proportional integral to determine the voltage reference value in the dq axis:
• according to the current reference value and the voltage reference value, construct a fuzzy control rule of a virtual damping coefficient and a virtual inertia,
• wherein, when the inverter is connected to the grid, the virtual damping coefficient and the virtual inertia are adjusted by the fuzzy control rule to control the inverter.