US-12627246-B1 - Electrically driven distillation system with variable dynamic load and a distillation method

US12627246B1US 12627246 B1US12627246 B1US 12627246B1US-12627246-B1

Abstract

The present invention provides an inverter control method, device, computer equipment and storage medium, belonging to the field of power electronics. The method comprises: determining a frequency control equation of the inverter under a grid-connected condition when the inverter is in a VSG control mode; determining a relationship between a virtual electromotive force of a virtual synchronous generator in a reactive state and an output voltage of the inverter; constructing a voltage-current double closed-loop control structure of the inverter under the VSG control mode, and determining a current reference value and a voltage reference value of the virtual synchronous generator under d q axes through the frequency control equation and the relationship; constructing a fuzzy control rule of a virtual damping coefficient and a virtual inertia according to the current reference value and the voltage reference value; and controlling the virtual damping coefficient and the virtual inertia through the fuzzy control rule, thereby improving the stability and performance of the inverter during the grid-connected process, reducing the harmonic disturbance of the power system, and helping to improve the adaptability and reliability of the entire photovoltaic power generation system.

Inventors

Meng Qi
Chengtian Cui
Xiaodong Zhang
Dongfeng Zhao

Assignees

CHINA UNIVERSITY OF PETROLEUM (EAST CHINA)

Dates

Publication Date: 20260512
Application Date: 20250117

Claims (9)

1 . 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 d q 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 d q 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 d q axis, and feedback is calculated with the actual output voltage value under the inverter VSG control mode under the d q axis; the result of feedback calculation is controlled by proportional integral to determine the d q axis reference current; the reference current is feedback-calculated with the actual output current component of the inverter VSG control mode in the d q axis, and the result of the feedback calculation is controlled by proportional integral to determine the voltage reference value in the d q 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.
2 . The inverter control method according to claim 1 , characterized in that the first relational expression is as follows: P m =P ref +k p ( w 0 −w ); Wherein, P m and P ref are the mechanical power and reference active power of the virtual synchronous generator, k p is the active power-frequency droop coefficient, w and w 0 are the grid-side angular velocity and reference angular velocity of the virtual synchronous generator.
3 . The inverter control method according to claim 2 , characterized in that the second relational expression is as follows: J ⁢ d ⁢ ω dt = T m - T e - T d = P m ω 0 - P e ω 0 - D ⁡ ( ω - ω 0 ) ; Wherein, J is the virtual inertia, T m , T e and T d are the mechanical torque, electromagnetic torque and damping torque of the virtual synchronous generator respectively, P e is the electromagnetic power of the virtual synchronous generator, D is the virtual damping coefficient, dω/dt is the time derivative of the grid-side angular velocity, that is, the rate of change of the grid-side angular velocity.
4 . The inverter control method according to claim 3 , characterized in that the frequency control equation is as follows: J ⁢ s ⁢ Δ ⁢ ω = P r ⁢ e ⁢ f + k p ( ω 0 - ω ) - P e ω 0 - D ⁡ ( ω - ω 0 ) ; Where, s is the equivalent moment of inertia and Δω is the angular frequency deviation.
5 . The inverter control method according to claim 1 , characterized in that the third relational expression is as follows: K ⁢ dE dt = Q ref - Q e + K q ( U n - U 0 ) ; Wherein, Q ref is the reference reactive power, Q e is the actual output reactive power, U n is the effective value of the terminal voltage, U 0 is the rated voltage, K q is the voltage droop coefficient, K is the reactive power regulation coefficient, and E is the no-load electromotive force.
6 . The inverter control method according to claim 1 , characterized in that the inverter is used to maintain the stability of the internal electromotive force of the energy storage system when the photovoltaic grid is connected; and the voltage reference value is used to characterize the internal electromotive force of the energy storage system.
7 . A computer-readable storage medium, characterized in that the storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the inverter control method according to claim 1 is implemented.
8 . A computer device, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the inverter control method according to claim 1 when executing the program.
9 . An inverter control device, characterized in that the device comprises: a determination module capable of simulating frequency modulation characteristics of a virtual synchronous generator (VSG) through the speed regulator when the inverter is in VSG control mode, determining a first relationship between active power-frequency droop characteristics of the VSG, and a second relationship between rotor angular velocity of the VSG and a virtual damping coefficient and virtual inertia of the inverter; determining a frequency control equation of the inverter under a grid-connected condition according to the first relationship and the second relationship; determining a third relationship between the virtual electromotive force of the virtual synchronous generator in the reactive state and the output voltage of the inverter; constructing a voltage-current dual closed-loop control structure of the inverter under the VSG control mode, and determining a current reference value and voltage reference value of the VSG under a d q axis through the frequency control equation and the third relationship; wherein determining the current reference value and the voltage reference value of the virtual synchronous generator under the d q 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 d q axis, and feedback is calculated with the actual output voltage value under the inverter VSG control mode under the d q axis; the result of feedback calculation is controlled by proportional integral to determine the d q axis reference current; the reference current is feedback-calculated with the actual output current component of the inverter VSG control mode in the d q axis, and the result of the feedback calculation is controlled by proportional integral to determine the voltage reference value in the d q axis: a construction module, used for constructing fuzzy control rules of virtual damping coefficient and virtual inertia according to the voltage reference value; and a control module is capable of controlling the virtual damping coefficient and the virtual inertia by using the fuzzy control rule when the inverter is connected to the grid.

Description

TECHNICAL FIELD The present invention belongs to the field of power electronics, and in particular relates to an inverter control method, device, computer equipment and storage medium. BACKGROUND ART With the proposal of China's “dual carbon” goals, China's distributed energy installed capacity has grown rapidly. A large-scale distributed energy base development model has become the mainstream, providing strong support for the development of the new energy industry. Since desert areas such as the Gobi desert have rich solar and wind energy resources, the country is focusing on promoting construction of large-scale wind power and photovoltaic bases in desert areas of the Gobi desert. In the prior art, photovoltaic power generation, as an important part of power grid transmission, is connected to the power grid through a grid-connected inverter. The grid-connected inverter has the advantage of fast response speed, but photovoltaic power generation has significant randomness and volatility in energy output, and the inverter lacks the rotational inertia and the ability to participate in frequency and voltage regulation of synchronous generators. This leads to reduced stability of the entire photovoltaic power generation system, and makes it difficult to adapt to the needs and changes of the power grid, resulting in a reduction in the grid's standby rotational inertia, and even affecting the overall stability of the power grid. SUMMARY OF THE INVENTION In order to solve the problem that the above inverter cannot maintain system stability in conjunction with photovoltaic grid connections, the present invention provides an inverter control method, device, computer equipment and storage medium. In order to achieve the above object, the present invention provides the following technical solutions: First, an inverter control method is provided, the method comprising: When the inverter is in a virtual synchronous generator VSG control mode, the frequency regulation characteristics of the virtual synchronous generator are simulated by the speed regulator to determine a first relational expression of the active power-frequency droop characteristics of the virtual synchronous generator and a second relational expression of the rotor angular velocity of the virtual synchronous generator and the virtual damping coefficient and virtual inertia of the inverter; A frequency control equation of the inverter in a grid-connected state according to the first relational expression and the second relational expression is determined;The virtual electromotive force of the virtual synchronous generator is adjusted, thereby adjusting the output of the reactive power of the inverter, and determining a third relationship between the virtual electromotive force of the virtual synchronous generator in the reactive state and the output voltage of the inverter;A voltage-current dual closed-loop control structure of the inverter in the VSG control mode is constructed, and the current reference value and the voltage reference value of the virtual synchronous generator under the dq axis through the frequency control equation and the third relationship is determined; According to the current reference value and the voltage reference value, a fuzzy control rule of a virtual damping coefficient and a virtual inertia is constructed; 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. Optionally, the first relational expression is as follows: Pm=Pref+kp(ω0−ω); Wherein, Pm and Pref are the mechanical power and reference active power of the virtual synchronous generator, respectively, kp is the active power-frequency droop coefficient, ω and ω0 are the grid-side angular velocity and reference angular velocity of the virtual synchronous generator, respectively. Optionally, the second relational expression is as follows: J⁢d⁢ωdt=Tm-Te-Td=Pmω0-Peω0-D⁡(ω-ω0); Wherein, J is the virtual inertia, Tm, Te and Td are the mechanical torque, electromagnetic torque and damping torque of the virtual synchronous generator respectively, Pe is the electromagnetic power of the virtual synchronous generator, D is the virtual damping coefficient, dω/dt which is the time derivative of the grid-side angular velocity, that is, the rate of change of the grid-side angular velocity. Optionally, the frequency control equation is as follows: J⁢s⁢Δ⁢ω=Pr⁢e⁢f+kp(ω0-ω)-Peω0-D⁡(ω-ω0); Where s is the equivalent moment of inertia and Δω is the angular frequency deviation. Optionally, the third relationship is as follows: K⁢dEdt=Qref-Qe+Kq(Un-U0); Wherein, Qref is the reference reactive power, Qe is the actual output reactive power, Un is the effective value of the terminal voltage, U0 is the rated voltage, Kq is the voltage droop coefficient, K is the reactive power regulation coefficient, and/is the no-load electromotive force. Optionally, the current reference value and th