CN-122026539-A - Multi-port converter input/output energy storage VSG joint control method, system, equipment and medium

CN122026539ACN 122026539 ACN122026539 ACN 122026539ACN-122026539-A

Abstract

The invention discloses a method, a system, equipment and a medium for jointly controlling input and output energy storage VSG of a multi-port converter, which relate to the technical field of power system control and comprise the steps of constructing a port control unit with virtual inertia and damping characteristics at an alternating current input port, a direct current output port and an energy storage port of the converter, and establishing a unified coordination mechanism of a penetrating port, based on the real-time power state of the DC bus of the converter, dynamically coupling the output of the port control unit, deploying a multi-mode smooth switching logic to enable the converter to switch on line between a voltage source operation mode and a power controlled operation mode, judging a switching trigger condition by the switching logic according to the system state, and reconstructing and smoothly transiting the internal state of each port control unit in the switching process. The invention solves the problem of converter multiport cooperative control, improves the stability and the power supply reliability of an alternating-current/direct-current system, and realizes the optimal utilization of undisturbed switching and adjustment resources of an operation mode.

Inventors

LIN CHENGHUI
LUO GUOQIANG
CHEN DUNHUI
Dai Qiji
LI XIANG
FENG QIHUI
TAN ZHUKUI
ZHANG YUELANG
ZHANG XUAN
WU YANG
CHEN XIAYU
LIU DONGDONG
ZHANG HOUYI

Assignees

贵州电网有限责任公司

Dates

Publication Date: 20260512
Application Date: 20251226

Claims (10)

1. The multi-port converter input/output energy storage VSG joint control method is characterized by comprising the steps of, Constructing a port control unit with virtual inertia and damping characteristics at an alternating current input port, a direct current output port and an energy storage port of the converter; establishing a unified coordination mechanism of the through port, dynamically coupling the output of the port control unit based on the real-time power state of the DC bus of the converter, and inhibiting the fluctuation of the frequency of the AC side and the voltage of the DC bus; And deploying a multi-mode smooth switching logic, wherein the converter is used for switching between a voltage source operation mode and a power controlled operation mode on line, judging a switching trigger condition according to a system state by the switching logic, and reconstructing and smoothly transiting the internal state of each port control unit in the switching process.
2. The method for jointly controlling the input and output energy storage VSG of the multi-port converter according to claim 1, wherein the establishing a unified coordination mechanism of the through port comprises the steps of monitoring system state deviation of an alternating current side and a direct current side, comprehensively solving the monitored system state deviation according to a preset deviation-power collaborative mapping relation to generate a coordination control instruction; and respectively issuing the coordination control instructions to the corresponding port control units, triggering the control actions, and executing the power changes generated by the control actions by the port control units, and mutually coupling through the direct current buses to counteract the power disturbance causing the system state deviation.
3. The method of claim 2, wherein the deviation-power collaborative mapping comprises dynamically allocating power adjustment shares to be respectively born by the AC input port and the energy storage port based on an instantaneous power coupling model according to the type and the amplitude of the system state deviation monitored in real time.
4. The method for jointly controlling the input and output energy storage VSG of the multi-port converter according to claim 3, wherein said multi-mode smooth switching logic includes evaluating a current operating state of the system based on a predefined operating mode switching criterion and generating an instruction to switch from the current operating mode to a target operating mode when the criterion condition is satisfied; And during the switching transition period, a reference instruction smooth gradual change method is adopted to ensure that the control reference quantity influenced by switching is transited from a steady-state value before switching to a target value after switching without step.
5. The method of claim 4, wherein the constructing the port control unit by the AC input port comprises establishing a virtual rotor motion equation simulating the mechanical dynamics of the synchronous generator rotor, converting the difference between the actually measured output active power and the reference active power into the change of the angular velocity and the phase of the virtual rotor by solving the equation, combining the voltage amplitude reference generated by the reactive-voltage droop control link with the phase as a reference to synthesize a reference waveform of the three-phase AC voltage, and driving the AC/DC converter to generate the actual output voltage and current by a double closed-loop controller consisting of a voltage outer loop and a current inner loop; the virtual rotor equation of motion is expressed as: Wherein, the For the virtual moment of inertia, For the virtual angular velocity of the rotor, For the rated angular velocity of the wheel, For the virtual mechanical power to be a function of the mechanical power, For the virtual electromagnetic power to be present, Is a virtual damping coefficient, which is a virtual damping coefficient, In order to be able to take time, As a reference value for the active power, Is the active-frequency droop coefficient; The direct current output port construction port control unit comprises the steps of calculating the deviation between the actual measurement value of the direct current bus voltage and the rated reference value in real time, multiplying the voltage deviation by a preset proportionality coefficient, mapping the voltage deviation into an equivalent virtual frequency deviation signal, taking the virtual frequency deviation signal as a feedforward compensation quantity, and introducing the feedforward compensation quantity into an input side or a power regulation link of a virtual rotor motion equation of an alternating current input port to obtain a correction quantity; The equivalent mapping relationship is expressed as: Wherein, the As an equivalent virtual frequency deviation signal, For the voltage deviation of the direct current bus, In order to map the scaling factor(s), Is the actual measurement value of the voltage of the direct current bus, Rated voltage of the direct current bus; the power adjustment formula is expressed as: Wherein, the In order to modify the virtual machine power command, To compensate for transfer functions; The energy storage port construction port control unit comprises a coordination control strategy of integrating direct current droop and power instruction following, wherein a power reference value is determined by the product of a fixed power set point and direct current bus voltage deviation regulated by droop coefficients, the power reference value is input into a power management ring, the power reference value is converted into a battery current reference value through a real-time battery terminal voltage, charge-discharge current limiting protection is executed, the current reference value is used as an instruction, a switching device of a bidirectional AC/DC converter is rapidly controlled through a current inner ring, a voltage outer ring which takes the direct current bus voltage as a controlled quantity is arranged in a discharge mode, and the output and the current reference value are overlapped to obtain a final current instruction; the power reference value calculation formula is expressed as: Wherein, the For the stored port power reference command, positive values indicate discharge, negative values indicate charge, A power set point is fixed for the energy storage port, The direct current droop coefficient of the energy storage port; The current reference value calculation formula is expressed as: Wherein, the As a reference value for the current of the battery, Is the measured value of the battery terminal voltage.
6. The method of claim 5 wherein the system state deviation comprises a deviation of an ac system frequency from a nominal frequency and a deviation of a dc bus voltage from a nominal voltage, expressed as: Wherein, the For the frequency deviation of the ac system, For the real-time frequency of the ac system, Rated frequency for the alternating current system; The deviation-power collaborative mapping relation further comprises the steps that the direct-current bus voltage deviation is converted into virtual frequency deviation through a mapping method, the virtual frequency deviation is used as an additional item to influence an alternating-current side power instruction, the alternating-current frequency deviation and the direct-current voltage deviation are input into a coordination controller together, and the controller calculates the superposition correction quantity of the energy storage port power reference instruction according to a preset sagging coefficient and weight to cooperatively restrain the two deviations; the dc bus power balance equation is expressed as: Wherein, the Is the equivalent capacitance of the direct current bus, Is the voltage of the direct current bus, and the voltage of the direct current bus is the voltage of the direct current bus, The first derivative of the dc bus voltage with respect to time, the voltage rate of change, Active power of the dc bus is injected into the ac input port, The power consumed by the load carried by the dc output port, Exchanging power between the energy storage port and the direct current bus; the calculated power difference formula is expressed as: Wherein, the Is the instantaneous power difference of the system; The calculation correction amount formula is expressed as: Wherein, the In order to modify the virtual machine power command, As an original virtual machine power command, For the feed-forward compensation of the transfer function, A coefficient is allocated for the ac port power, For the modified tank port power reference command, And (5) distributing coefficients for the power of the energy storage ports.
7. The method for jointly controlling the input and output energy storage VSG of the multi-port converter according to claim 6, wherein the cross-mode state mapping method comprises the steps of calculating an initial voltage amplitude reference and a voltage phase reference in a voltage source mode by solving a relation equation of active power and power angle and a relation equation of reactive power and voltage amplitude according to an output active power value, a reactive power value, a power grid voltage amplitude and a preset virtual synchronous reactance value of the converter detected at a switching moment when the power control mode is switched to a voltage source mode, estimating an initial active power reference value and a reactive power reference value in the power control mode according to the output voltage amplitude, the output voltage phase, the power grid voltage amplitude, the phase and line impedance parameters of the converter at the switching moment when the power control mode is switched to the power control mode, and resetting an integral state of a proportional-integral regulator in a control loop affected by the mode switching; the equation for solving the relation between the active power and the active angle is expressed as: Wherein, the Is the power angle of the power point, Active power is output for the VSG detected at the moment of switching, For a virtual synchronous reactance that is a function of the frequency of the power source, For the initial amplitude of the VSG output voltage to be solved, For switching the detected grid voltage amplitude at the instant, Outputting reactive power for the VSG detected at the switching instant; the calculation of the initial voltage amplitude reference and the voltage phase reference are expressed as: Wherein, the To refer to the command for the initial voltage amplitude when switching to the voltage source mode, For an initial voltage phase reference command when switching to the voltage source mode, A power grid voltage phase at the switching instant; the initial active power reference and reactive power reference in the estimated power control mode are formulated as: Wherein, the For the initialized active power reference value, For the initialized reactive power reference value, To switch the output voltage phase of the instant VSG, For the line impedance magnitude value, As a component of the line resistance, For the line reactance component, Is the line impedance angle; The reference instruction smooth gradual change method comprises the following steps that a control reference quantity to be switched is changed from an initial value of a switching starting moment to a target value of a switching target moment according to a linear rule in a preset transition time, and a slope function is subjected to a smooth processing formula to be expressed as: Wherein, the For the control reference command value at time t, For the initial value of the reference quantity at the start time of the handover, For the reference target value at the time of completion of the switch, The total switching transition time is preset.
8. The multi-port converter input/output energy storage VSG joint control system is applied to the multi-port converter input/output energy storage VSG joint control method according to any one of claims 1-7, and is characterized by comprising an AC side virtual synchronous machine control module, a DC side equivalent virtual synchronous machine control module, an energy storage port VSG and sagging coordination control module and a multi-mode online smooth switching control module; the AC side virtual synchronous machine control module is used for simulating the mechanical inertia and damping characteristics of a real synchronous generator by establishing and solving a virtual rotor motion equation at an alternating current input port, receiving active power instructions and feedback in real time, dynamically generating virtual frequency and phase signals with inertia buffering effect, and synthesizing a three-phase voltage reference waveform; the DC side equivalent virtual synchronous machine control module is used for establishing an equivalent virtual synchronous machine mechanism on a DC side, mapping the deviation of the DC bus voltage into an equivalent virtual frequency disturbance signal according to a proportion, and introducing the signal into a power regulation loop on an AC side as a feedforward quantity; The energy storage port VSG and the sagging coordination control module are used for integrating sagging characteristics and a double-layer control structure for rapid power tracking in the energy storage system design, the upper layer comprehensively generates a power support instruction through a sagging algorithm according to direct current voltage deviation and alternating current frequency deviation, and the lower layer is controlled through a high-bandwidth current-voltage double closed loop; The multi-mode online smooth switching control module is used for triggering switching based on criteria, initializing a control variable of a target mode through a state mapping algorithm at the switching moment, and carrying out smooth gradual change on a reference instruction by adopting a slope function.
9. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor, when executing the computer program, implements the steps of the multi-port converter input output energy storage VSG joint control method of any of claims 1 to 7.
10. A computer readable storage medium having stored thereon a computer program, wherein the computer program when executed by a processor implements the steps of the multi-port converter input output stored energy VSG joint control method of any of claims 1 to 7.

Description

Multi-port converter input/output energy storage VSG joint control method, system, equipment and medium Technical Field The invention relates to the technical field of power system control, in particular to a multi-port converter input-output energy storage VSG joint control method, a system, equipment and a medium. Background The light Chu Zhi flexible building is used as a novel low-carbon building form, the stable operation of a direct current power supply and distribution system becomes a key technical pain point, wherein an isolated AC/DC converter is a core junction for connecting a direct current micro-grid in the building with a public alternating current power grid, and is used for carrying out energy bidirectional transmission tasks of photovoltaic power grid connection, energy storage bidirectional charge and discharge and emergency energy supplement of the alternating current power grid, however, the switching characteristics of the traditional power electronic converter are completely different from synchronous generators, and have no mechanical inertia and inherent damping, when the light Fu Fuzhao mutation (such as cloud cover) is encountered, the charge and discharge modes of an energy storage unit are rapidly switched, or a large-capacity direct current load (such as a charge pile and a central air conditioner) in the building is instantaneously switched, the frequency and the voltage transient instability of the alternating current side are easily caused, even the harmonic exceeding of the power grid is caused, the huge impact is brought to the safe operation of the power distribution network, meanwhile, the voltage of a low-voltage direct current bus can be greatly fluctuated, and the voltage exceeds the tolerance threshold of equipment in serious. The existing Virtual Synchronous Generator (VSG) control strategy focuses on stable regulation and control of a single port, or performs inertial simulation only on an alternating current grid-connected side, or performs voltage stabilization only on a direct current bus side, so that cooperative linkage of an input stage AC port, an output stage DC port and an energy storage port cannot be realized, the quick response capability of the energy storage unit cannot be fully released, the control of the alternating current side and the direct current side is disjointed, the power supply reliability of a system is reduced, the friendly interaction capability of a light Chu Zhi flexible building on a power grid is restricted, and therefore a VSG combined control system with multiple ports and multiple layers and supporting on-line mode switching is constructed, and the urgent requirement for improving the overall stability and the operation flexibility of the system is already met. Disclosure of Invention In view of the above existing problems, the present invention provides a method, a system, a device and a medium for controlling a multi-port converter in combination with an input/output energy storage VSG, which are used for solving the problems that in the prior art, the quick response capability of an energy storage unit cannot be fully released, the control of an ac side and a dc side is disjointed, and the power supply reliability of the system is reduced. In order to solve the technical problems, the method for jointly controlling the input and output energy storage VSG of the multi-port converter is provided, which comprises the following steps, The method comprises the steps of constructing a port control unit with virtual inertia and damping characteristics at an alternating current input port, a direct current output port and an energy storage port of a converter, establishing a unified coordination mechanism of a penetrating port, dynamically coupling the output of the port control unit based on the real-time power state of a direct current bus of the converter, restraining the voltage fluctuation of the alternating current side and the direct current bus, deploying a multi-mode smooth switching logic, judging a switching trigger condition according to the system state by the switching logic between an on-line switching voltage source operation mode and a power controlled operation mode of the converter, and reconstructing and smoothly transiting the internal state of each port control unit in the switching process. The method for controlling the input/output energy storage VSG of the multi-port converter comprises the steps of monitoring system state deviation of an alternating current side and a direct current side, comprehensively resolving the monitored system state deviation according to a preset deviation-power collaborative mapping relation to generate a coordination control instruction; and respectively issuing the coordination control instructions to the corresponding port control units, triggering the control actions, and executing the power changes generated by the control actions by the port control units, and mutually coupl