Active power distribution network multi-resource cooperative on-grid and off-grid control method and device and storage medium

Abstract

The application provides a kind of active power distribution network multi-resource collaborative on-grid and off-grid control method, device and storage medium, the method comprises: determining the voltage active component U a And voltage reactive component U r Of line impedance voltage according to the initial signal of converter;If power distribution network fails, the phase instruction of converter output current is dynamically adjusted based on the voltage active component U a And voltage reactive component U r Of line impedance voltage, realize the control of converter output current in off-grid state;If power distribution network restores power supply, realize the control of converter output current in on-grid state based on current operating state.The present application not only can get rid of the dependence on satellite time signal, and can realize the flexible control of converter output current phase during on-grid to autonomous, which is beneficial to reduce the cost of equipment and improve the operation reliability of equipment.

Description

Technical Field

[0001] This invention relates to the field of power grid control technology, and in particular to a method, device and storage medium for multi-resource coordinated and off-grid control of active distribution networks. Background Technology

[0002] With the increasing penetration rate of distributed power sources and energy storage devices in power distribution networks, ensuring stable power supply under unstable external conditions has become an urgent technical problem to be solved.

[0003] In existing technologies, based on the characteristics of the operating frequency of autonomous distribution networks, they can be divided into two types: network construction technology similar to a virtual synchronous machine and fixed-frequency network construction technology. The former is prone to transient current surges under complex grid connection control conditions or when the load fluctuates drastically; the latter relies on satellites for time synchronization, which increases the cost of the equipment. Summary of the Invention

[0004] Based on this, this application provides an active distribution network multi-resource collaborative on-grid and off-grid control method, device and storage medium, which can ensure the stability of the output current of the distribution network converter under complex on-grid and off-grid control states and when the load fluctuates drastically without relying on satellites.

[0005] In a first aspect, embodiments of the present invention provide a method for multi-resource coordinated off-grid control of an active distribution network, the method comprising: S102: determining the voltage active component U of the line impedance voltage based on the initial signal of the converter. a and voltage reactive component U r S104: If a fault occurs in the distribution network, the active voltage component U based on the line impedance voltage... a and voltage reactive component U r Synchronously and dynamically adjust the phase command of the converter output current to realize the control of the converter output current in the off-grid state; S106: If the power distribution network resumes power supply, the control of the converter output current in the grid-connected state is realized based on the current operating state.

[0006] Further, S102 includes: S1022: determining the direct-axis component u of the converter port voltage under different operating conditions based on the real-time acquired initial signal of the converter. d Port voltage quadrature axis component u q and the direct-axis component i of the converter output current d Output current quadrature axis component i q S1024: Calculate the direct-axis component difference Δu of the port voltage under any two different operating conditions. d Port voltage quadrature axis component difference Δu q The difference in the direct-axis component of the output current Δi d Output current quadrature axis component difference Δi qS1026: Based on the difference Δu of the direct-axis components of the port voltage under any two different operating states d Port voltage quadrature axis component difference Δu q The difference in the direct-axis component of the output current Δi d Output current quadrature axis component difference Δi q Determine the average resistive component of the line impedance and average sensory component S1028: Based on the real-time acquired phase-locked loop A-phase voltage phase signal θ AU Determine the active current component I of the converter output current. oa and reactive component of current I or S10210: Active current component I based on the output current of the converter oa Reactive component of current I or Average resistive component of line impedance and average sensory component The line impedance voltage is decomposed into an active voltage component U. a and voltage reactive component U r .

[0007] Further, S104 includes: S1042: based on the voltage active component U of the line impedance voltage a and voltage reactive component U r Confirm the current phase signal θ of phase-locked loop A-phase voltage. AU Preliminary phase command signal θ, which is synchronized globally with the prior acquisition s The first phase difference between S1044: Based on the first phase difference The phase signal θ of phase-locked loop A-phase voltage acquired in real time AU Dynamic adjustment is performed to obtain the real-time phase command signal θ. srt S1046: In the off-grid state, according to the real-time phase command signal θ srt Control the output current of the converter.

[0008] Furthermore, S1042 includes: S10422: Real-time calculation of the direct-axis component u of the converter port voltage obtained from S1022. d and port voltage cross-axis component u q Determine the phase voltage amplitude information V at the converter port 端口 S10424: Based on the port phase voltage amplitude information V 端口 The active voltage component U of the line impedance voltage a and voltage reactive component U r Determine the phase offset angle S10426: Based on the currently acquired fault occurrence time, the preset tracing time interval Δt, and the phase offset angle. The initial phase command signal θ for global synchronization is obtained. s S10428: Initial phase command signal θ for global synchronization s Phase signal θ of phase-locked loop A-phase voltage at the current moment AU The first phase difference is obtained by subtraction.

[0009] Further, S1044 includes: S10442: if the first phase difference <The preset first phase threshold is then based on the first gradient frequency f a The preset tracking time interval Δt and the real-time phase-locked loop A-phase voltage phase signal θ AU Obtain the real-time phase command signal θ srt Wherein, the first gradient frequency f a It is obtained based on dynamic adjustment of proportional-integral operations; S10444: If the first phase difference If the first phase threshold is greater than or equal to the preset threshold, then the second gradient frequency f is used. b The preset tracking time interval Δt and the real-time phase-locked loop A-phase voltage phase signal θ AU Obtain the real-time phase command signal θ srt Wherein, the second gradient frequency f b It is obtained by dynamic adjustment based on proportional-integral calculation.

[0010] Further, S1046 includes: S10462: Based on the converter three-phase port voltage signal u in the real-time acquired initial signal of the converter. a u b u c Determine the active current command information of the converter (cmd) Ia and reactive current command information cmd Ir S10464: According to the real-time phase command signal θ srt For voltage signal u a u b u c After transformation and filtering, the active current component I of the converter output current in the off-grid state is obtained. oa_离网 and the reactive component of current I or_离网 S10466: According to the active current command information cmd of the converter Ia and reactive current command information cmd Ir The active current component I of the converter output current in off-grid mode oa_离网 and the reactive component of current I or_离网The three-phase modulated wave signals xa, xb, and xc in the stationary coordinate system are obtained; S10468: The three-phase modulated wave signals xa, xb, and xc are subjected to pulse width modulation or space vector pulse width modulation to obtain the control signal Y of the switch, and the output current of the converter is controlled based on the control signal Y.

[0011] Furthermore, in S104, the step of determining whether a fault has occurred in the distribution network includes: if the real-time acquired converter port phase voltage amplitude information V 端口 If the voltage exceeds the preset first voltage threshold, a fault is considered to have occurred in the distribution network; if the real-time acquired converter port phase voltage amplitude information V 端口 >The preset second voltage threshold is considered to indicate that no fault has occurred in the distribution network; if the converter port phase voltage amplitude information V 端口 Between the preset first voltage threshold and the preset second voltage threshold, the angle sum θ is calculated. SUM If the sum of the angles θ SUM If the voltage is not within the preset summation threshold range, the distribution network is considered to have a fault; otherwise, the distribution network is considered not to have a fault. Wherein, the first voltage threshold is less than the second voltage threshold.

[0012] Furthermore, in S104, the sum of angles θ is calculated. SUM The steps include: injecting a preset amount of reactive power into the distribution network, and based on the port voltage amplitude V after the reactive power injection. 端口 and the phase signal θ of phase A voltage AU Determine the sum of angles θ SUM .

[0013] Furthermore, in S106, the step of determining whether the distribution network has resumed power supply includes: based on the active current component I of the converter output current under continuous different operating conditions. oa Reactive component of current I or A first angle value is determined. If the first angle value is greater than a preset first angle threshold, the count is incremented to obtain a count value. If the first angle value is less than or equal to the preset first angle threshold, the count value is cleared to zero. When the count value is greater than a preset control threshold, the power distribution network is considered to have resumed power supply.

[0014] Furthermore, in S106, the step of determining whether the power distribution network has been restored to power also includes: confirming whether the power distribution network has been restored to power based on the switch status at the common bus of the power distribution network received by the converter.

[0015] Furthermore, S106 includes: S1062: Based on the active power P of the converter under the current operating state... ref and reactive power Q ref Determine the active current command information of the converter (cmd) Ia′ and reactive current command information cmd Ir S1064: Based on the current phase-locked loop A-phase voltage phase signal θ AU For the three-phase output current signal i in the current initial signal oa i ob i oc Transformation and filtering are performed to obtain the active current component I of the converter output current under grid-connected conditions. oa_并网 and the reactive component of current I or_并网 S1066: Based on the converter active current command information cmd Ia ′ and reactive current command information cmd Ir The active current component I of the converter output current under grid-connected conditions. oa_并网 and the reactive component of current I or_并网 S1068: Obtain the three-phase modulated wave signals xa', xb', and xc' in the stationary coordinate system; S1068: Perform pulse width modulation or space vector pulse width modulation on the three-phase modulated wave signals xa', xb', and xc' to obtain the control signal Y' of the switch, and control the output current of the converter based on the control signal Y'.

[0016] Furthermore, S104 includes: if no fault occurs in the distribution network, then S106 is executed.

[0017] Furthermore, S106 includes: if the power distribution network has not been restored, then S104 shall be executed.

[0018] Further, S10462 includes: S104622: based on the phase signal θ of the phase-locked loop A-phase voltage. AU For the three-phase port voltage signal u of the converter a u b u c The voltage reactive component U of the converter port voltage is obtained by using Clarke transform, Park transform, and filtering. or_变流器 S104624: Based on the pre-acquired converter port voltage amplitude command U set and converter port voltage amplitude V 端口 Determine the initial active current command information for the converter (cmd) Ia0 S104626: Voltage reactive component U of the converter port voltage or_变流器 After negation, proportional-integral calculation is performed to obtain the initial converter reactive current command information cmd. Ir0 S104628: Initial converter active current command information cmd Ia0 Initial converter reactive current command information cmd Ir0 The active current command information (cmd) of the converter is obtained by making corrections respectively. Iaand reactive current command information cmd Ir .

[0019] Furthermore, in S104624, the instruction U for obtaining the port voltage amplitude of the converter is... set The steps include: based on the current active power command value P ref The active power command value P at the previous moment ref0 The converter port voltage amplitude command U from the previous moment set0 Real-time acquisition of converter port phase voltage amplitude information V 端口 Average resistive component of line impedance Command U to determine the port voltage amplitude of the converter set Alternatively, based on the current off-grid topology and line impedance, the port voltage amplitude command U of the converter in the distribution network can be obtained through power flow calculation. set .

[0020] Secondly, embodiments of the present invention provide an active power distribution network multi-resource coordinated on-grid and off-grid control device, the device comprising: a first control module, used to determine the voltage active component U of the line impedance voltage based on the initial signal of the converter. a and voltage reactive component U r The second control module is used to, in the event of a fault in the distribution network, determine the active voltage component U based on the line impedance voltage. a and voltage reactive component U r The phase command for synchronously and dynamically adjusting the converter output current enables control of the converter output current in the off-grid state; the third control module is used to control the converter output current in the grid-connected state based on the current operating state if the power distribution network is restored.

[0021] Thirdly, embodiments of the present invention provide an electronic device, including: at least one processor; and at least one memory communicatively connected to the processor, wherein: the memory stores program instructions executable by the processor, and the processor can execute the above-described active power distribution network multi-resource coordination and off-grid control method by calling the program instructions.

[0022] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing computer instructions that cause the computer to execute the above-described active power distribution network multi-resource coordination and off-grid control method.

[0023] The beneficial effects of the embodiments of the present invention are as follows:

[0024] This invention provides a method, apparatus, and storage medium for multi-resource coordinated on-grid and off-grid control in an active distribution network, comprising: determining the voltage active component U of the line impedance voltage based on the initial signal of the converter.a and voltage reactive component U r If a fault occurs in the distribution network, the active voltage component U based on the line impedance voltage will be... a and voltage reactive component U r The converter phase is dynamically adjusted synchronously to control the converter output current in off-grid mode; if the distribution network resumes power supply, the converter output current can be controlled in grid-connected mode based on the current operating status. This application not only eliminates the dependence on satellite timing signals but also enables flexible control of the converter output current phase during the transition from grid-connected to autonomous operation, which helps reduce equipment costs and improve equipment operational reliability. Attached Figure Description

[0025] Figure 1 A flowchart of an active power distribution network multi-resource collaborative on-grid and off-grid control method provided for the implementation of this invention;

[0026] Figure 2 A schematic diagram of another active power distribution network multi-resource collaborative on-grid and off-grid control device provided for the implementation of the present invention;

[0027] Figure 3 A schematic diagram of an active power distribution network multi-resource collaborative on-grid and off-grid control device provided for the implementation of this invention;

[0028] Figure 4 A schematic diagram of an active power distribution network multi-resource collaborative and off-grid control electronic device provided for the implementation of this invention. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] With the increasing penetration rate of distributed power sources and energy storage devices in distribution networks, it is easier for distribution networks to achieve local power balancing. Distribution networks can restore power to local loads in the form of planned islands / microgrids when the main power grid is out of service, which is of great significance for resisting the damage of natural disasters and war, and improving the reliability of power supply.

[0031] Islanded systems with a high proportion of new energy sources and power electronic devices have low inertia and no longer possess the electromechanical characteristics of traditional synchronous machines. Therefore, they require network construction techniques to support the frequency and voltage of autonomous distribution networks. Based on the characteristics of the operating frequency of autonomous distribution networks, network construction techniques can be divided into two types: those similar to virtual synchronous machines and those based on fixed frequency. The former struggles with power-angle and frequency stability issues during severe load fluctuations, is difficult to implement plug-and-play, has complex multi-distribution interconnection control, and is prone to transient current surges. The latter often employs satellite-based time synchronization technology, which can achieve fixed-frequency operation and avoid frequency deviations in steady state, but its reliance on time synchronization tools increases the cost of the equipment.

[0032] Example 1

[0033] like Figure 1 As shown, this embodiment proposes a multi-resource collaborative on-grid and off-grid control method for active distribution networks, including:

[0034] S102: Determine the active voltage component U of the line impedance voltage based on the initial signal of the converter. a and voltage reactive component U r ;

[0035] S104: If a fault occurs in the distribution network, the voltage active component U based on the line impedance voltage... a and voltage reactive component U r The phase command of the converter output current is synchronously and dynamically adjusted to realize the control of the converter output current in the off-grid state;

[0036] S106: If the power distribution network resumes power supply, the output current of the converter under grid-connected status will be controlled based on the current operating status.

[0037] Specifically, the operating status of the distribution network includes the active power and reactive power of the converters.

[0038] S102-106 can be summarized as follows: The converter acquires and processes the three-phase voltage and three-phase current signals at its grid connection point; it performs calculations on the acquired phase voltage and current signals of the converter under different operating conditions to calculate the line impedance from the converter to the common bus (the impedance is decomposed into voltage active component U). a and voltage reactive component U r Further, the phase of phase A voltage and its phase deviation angle from the common bus voltage are calculated and recorded. The phase voltage amplitude and phase information are calculated to determine if an AC fault has occurred. If a fault occurs, the time synchronization of each distributed power converter is achieved based on the phase of phase A voltage and its phase deviation angle recorded before the fault. The active and reactive current command signals obtained through closed-loop control of the port voltage amplitude are used to achieve fixed-frequency grid-connected control of the energy storage converter. Then, the phase difference between the phase voltage and phase current is used to determine whether the grid has resumed power supply. When no fault occurs or the grid resumes power supply, the converter output current is controlled in grid-connected mode. The fixed-frequency grid-connected control in this embodiment not only eliminates the dependence on satellite timing signals but also enables flexible control of the converter output current phase during the transition from grid connection to autonomous operation. This helps reduce equipment costs and improve equipment operational reliability.

[0039] This invention provides a method, apparatus, and storage medium for multi-resource coordinated on-grid and off-grid control in an active distribution network, comprising: determining the voltage active component U of the line impedance voltage based on the initial signal of the converter. aand voltage reactive component U r If a fault occurs in the distribution network, the active voltage component U based on the line impedance voltage will be... a and voltage reactive component U r The converter phase is dynamically adjusted synchronously to control the converter output current in off-grid mode; if the distribution network resumes power supply, the converter output current can be controlled in grid-connected mode based on the current operating status. This application not only eliminates the dependence on satellite timing signals but also enables flexible control of the converter output current phase during the transition from grid-connected to autonomous operation, which helps reduce equipment costs and improve equipment operational reliability.

[0040] Example 2

[0041] This embodiment is a detailed explanation of Embodiment 1, as follows: Figure 2 As shown.

[0042] S102: Based on the converter's initial signal (i.e. Figure 2 (Processing signal) to determine the active voltage component U of the line impedance voltage a and voltage reactive component U r (Right now Figure 2 (Line impedance from the converter to the common bus).

[0043] S104: If a fault occurs in the distribution network, the voltage active component U based on the line impedance voltage... a and voltage reactive component U r The phase command of the converter output current is synchronously and dynamically adjusted, thereby realizing the control of the converter output current in the off-grid state (i.e., Figure 2 The energy storage converter adopts fixed-frequency grid control.

[0044] Specifically, the energy storage converter in the autonomous system adopts grid-connected control with a fixed frequency of 50Hz, while the photovoltaic and wind turbine converters can adopt grid-connected control with a fixed frequency of 50Hz or grid-following control before autonomous operation (such as closed-loop control of active and reactive power) to achieve closed-loop control of the converter output current.

[0045] S104 includes: If no fault occurs in the distribution network, then execute S106.

[0046] S106: If the power distribution network resumes power supply, then based on the current operating status, control the converter output current under grid-connected conditions (i.e., Figure 2 The converter adopts grid-connected control to achieve closed-loop control of the output current.

[0047] S106 includes: If the power distribution network has not been restored, then S104 shall be executed.

[0048] The following is a detailed introduction to S102:

[0049] S102 includes:

[0050] S1022: Determine the direct-axis component u of the converter port voltage under different operating conditions based on the real-time acquired initial signal of the converter. d Port voltage quadrature axis component u q and the direct-axis component i of the converter output current d Output current quadrature axis component i q .

[0051] Specifically, the initial signals of the converters include, but are not limited to, the three-phase voltage signals u at each converter's grid connection point. a u b u c Three-phase output current signal i oa i ob i oc The current direction is defined as the direction in which it flows into the converter. All the above data are instantaneous values ​​and can be collected in real time.

[0052] Specifically, different operating states of the distribution network correspond to different converter transmission powers, and different initial signals are generated under different transmission powers. In order to make the data more accurate, the initial signals can be collected multiple times under different transmission powers.

[0053] S1024: Calculate the direct-axis component difference Δu of the port voltage under any two different operating conditions. d Port voltage quadrature axis component difference Δu q The difference in the direct-axis component of the output current Δi d Output current quadrature axis component difference Δi q .

[0054] S1026: Based on the direct-axis component difference Δu of the port voltage under any two different operating states d Port voltage quadrature axis component difference Δu q The difference in the direct-axis component of the output current Δi d Output current quadrature axis component difference Δi q Determine the average resistive component of the line impedance and average sensory component

[0055] S1028: Based on the real-time acquired phase-locked loop A-phase voltage phase signal θ AU Determine the active current component I of the converter output current. oa and reactive component of current I or ;

[0056] S10210: Current active component I based on the output current of the converter oa Reactive component of current Ior Average resistive component of line impedance and average sensory component The line impedance voltage is decomposed into the active current component U. a and reactive component of current U r .

[0057] Specifically, S1022-S10210 includes 1)-9):

[0058] 1) Each converter spontaneously generates a phase signal θ with a fixed frequency of 50Hz using its own controller. F ;

[0059] 2) Based on the obtained phase signal θ F The three-phase voltage signal u is acquired. a u b u c The Clarke transform and Park transform are applied sequentially, followed by filtering with a low-pass filter (cutoff frequency greater than 10Hz and less than 50Hz) to obtain the direct-axis component u of the converter port voltage. d and cross-axis component u q ;

[0060] 3) Based on the obtained phase signal θ F For the three-phase output current signal i oa i ob i oc The Clarke transform and Park transform are applied sequentially, followed by filtering with a low-pass filter (cutoff frequency greater than 10Hz and less than 50Hz) to obtain the direct-axis component i of the converter output current. d and cross-axis component i q ;

[0061] 4) 10ms interval (when the output power changes, generally after half a power frequency cycle i) d andi q (It will be stable) Record the direct-axis and quadrature-axis components u of the converter port voltage and output current. d u q i d i q When the direct-axis component i of the output current d Or the cross-axis component i q When the change in value compared to the previous recorded value exceeds 10% of the previous value, it is considered that the transmission power has changed; by determining this, the direct-axis and quadrature-axis components u of multiple sets of converter port voltages and output currents are obtained. d u q i d i q And record it in memory.

[0062] Different operating states correspond to different transmission powers. Under different transmission powers, the direct-axis component u of the converter port voltage... d , cross-axis component u q The direct-axis component i of the output current d Cross-axis component i q Phase signal θ F Data such as three-phase voltage signals and three-phase output current signals will change.

[0063] 5) Randomly select two components to calculate the resistive component R and the inductive component X of the line impedance. L :

[0064] Using the direct-axis components of the two-port voltage u d The difference is obtained by subtracting the direct-axis components of the port voltage, Δu. d Using the cross-axis components u of the two port voltages q The difference between the cross-axis components of the port voltage is obtained by subtraction Δu. q ; Utilizing the direct-axis components i of the two sets of output currents in corresponding order d The difference is obtained by subtracting the direct-axis components of the output current, Δi. d Using the cross-axis components i of two sets of output currents in corresponding order q The difference is obtained by subtracting the cross-axis components of the output current, Δi. q ; Utilizing the difference in the direct-axis components of the output current Δi d The square of the sum of the quadrature-axis component difference of the output current Δi q The square of the difference between the direct and quadrature components of the output current is obtained by summing the squares of the differences:

[0065]

[0066] The direct-axis component difference of the port voltage Δu d Multiplied by the difference in the direct-axis components of the output current, Δi d The difference between the port voltage cross-axis components Δu q Multiply by the difference in the quadrature axis components of the output current, Δi q Sum the two values ​​above, and divide the sum by the sum of the squares of the differences between the direct and quadrature components of the output current. By taking the negative of this value, we obtain the resistive component R of the line impedance;

[0067]

[0068] Multiply the difference in the quadrature-axis components of the port voltage by the difference in the direct-axis components of the output current, multiply the difference in the direct-axis components of the port voltage by the difference in the quadrature-axis components of the output current, subtract the second value from the first value, divide this difference by the sum of the squares of the differences in the quadrature and direct-axis components of the output current, and take the negative of this value to obtain the inductive component X of the line impedance. L ;

[0069]

[0070] 6) Take the direct-axis and quadrature-axis components of the converter port voltage and output current from two sets of different combinations, and repeat the calculation to obtain at least three sets of resistive component R and inductive component X values ​​of the line impedance. L By averaging, the average resistive component of the line impedance is obtained. and average sensory component

[0071] 7) Based on the real-time acquired phase-locked loop A-phase voltage phase signal θ AU Determine the active current component I of the converter output current. oa and reactive component of current I or .

[0072] Specifically, based on the phase signal θ of phase A voltage obtained from the phase-locked loop... AU For the three-phase output current signal i oa i ob i oc The active current component I of the converter output current is obtained by sequentially applying the Clarke transform and Park transform, followed by filtering with a low-pass filter (cutoff frequency greater than 10Hz and less than 50Hz). oa and the reactive component of current I or .

[0073] 8) Calculate the reactive component U of the line impedance voltage. r Its value is equal to the sum of the two components:

[0074] The first component is the active current component I of the converter output current. oa With the average inductive component of the line impedance Z The product;

[0075] The second component is the reactive current component I of the converter output current. or With the average resistive component of the line impedance The product;

[0076]

[0077] 9) Calculate the active current component U of the line impedance voltage. a Its value is equal to the difference between the two components:

[0078] The first component is the active current component I of the converter output current. oa With the average resistive component of the line impedance The product of

[0079] The second sub-item is the reactive current component I of the converter output current.or With average sensory component The product;

[0080]

[0081] The following is a detailed introduction to S104:

[0082] S104 includes:

[0083] S1042: Based on the active voltage component U of the line impedance voltage a and voltage reactive component U r Confirm the current phase signal θ of phase-locked loop A-phase voltage. AU Preliminary phase command signal θ, which is synchronized globally with the prior acquisition s The first phase difference between (Right now Figure 2 (voltage phase deviation angle).

[0084] S1042 includes:

[0085] S10422: Real-time calculation of the direct-axis component u of the converter port voltage obtained from S1022. d and port voltage cross-axis component u q Determine the phase voltage amplitude information V at the converter port 端口 .

[0086] Specifically, based on the direct-axis component u of the converter port voltage obtained in real time d and cross-axis component u q The square root of the sum of the squares of the direct-axis and quadrature-axis components is taken to obtain the amplitude information V of the phase voltage at the converter port. 端口 Under different operating conditions, the corresponding converter port phase voltage amplitude information V 端口 .

[0087] S10424: Based on the port phase voltage amplitude information V 端口 The active voltage component U of the line impedance voltage a and voltage reactive component U r Determine the phase offset angle Where arctan is the arctangent calculation;

[0088]

[0089] S10426: Based on the currently acquired fault occurrence time, the preset tracing time interval Δt, and the phase offset angle. The initial phase command signal θ for global synchronization is obtained. s .

[0090] S10426 includes: based on the determined time of the fault occurrence, tracing back a certain time interval Δt (generally not less than 100ms), setting this time as zero, and taking the phase θ of phase A voltage at the zero time. AU Voltage phase offset angle calculated with S10424 The difference between the former and the latter is used as the initial phase θ0, and then θ is calculated. s :

[0091]

[0092] Where Δt is the preset time interval for retracing, and the time unit is seconds.

[0093] S10428: Initial phase command signal θ for global synchronization s Phase θ of phase A voltage at time zero AU The first phase difference is obtained by subtraction.

[0094]

[0095] S1044: Based on the first phase difference The phase signal θ of phase-locked loop A-phase voltage acquired in real time AU Dynamic adjustment is performed to obtain the real-time phase command signal θ. srt .

[0096] S1044 includes:

[0097] S10442: If the first phase difference <The preset first phase threshold is then based on the first gradient frequency f a And the preset tracking time interval Δt and the real-time phase-locked loop A-phase voltage phase signal θ AU Obtain the real-time phase command signal θ srt Wherein, the first gradient frequency f a It is obtained by dynamic adjustment based on proportional-integral calculation;

[0098] S10444: If the first phase difference If the first phase threshold is greater than or equal to the preset threshold, then the second gradient frequency f is used. b And the preset tracking time interval Δt and the real-time phase-locked loop A-phase voltage phase signal θ AU Obtain the real-time phase command signal θ srt Wherein, the second gradient frequency f b It is obtained by dynamic adjustment based on proportional-integral calculation.

[0099] More specifically, S1044 includes:

[0100] 1) If the phase difference value Less than 3.1415926 radians:

[0101] θ srt =θ AU +f a ×2π×Δt; Formula 9;

[0102] The first gradient frequency f a The initial value is 50.1Hz. The dynamic adjustment is a PI (proportional plus integral) operation of the phase angle difference. The proportional coefficient and integral coefficient ensure that the dynamic adjustment of the frequency is less than 0.1Hz, and the steady-state gradient frequency is 50Hz.

[0103] 2) If the phase difference value Greater than 3.1415926 radians:

[0104] θ srt =θ AU +f b ×2π×Δt formula 10;

[0105] Where the gradient frequency f b The initial value is 49.9Hz. The dynamic adjustment is a PI (proportional plus integral) operation (phase angle difference minus 2*pi). The proportional and integral coefficients ensure that the dynamic frequency adjustment is less than 0.1Hz, and the steady-state gradient frequency is 50Hz. If the dynamic frequency adjustment is less than 0.1Hz, it will be limited if it is greater than 0.1Hz.

[0106] The frequency fluctuation of a large-capacity system is generally ±0.2Hz. Considering the initial adjustment speed and the output effect of the regulator, half of it can be taken as the initial adjustment value in specific implementation, and is generally used as the adjustment effect: 50.1 = 50 + 0.1, 49.9 = 50 - 0.1.

[0107]

[0108] Among them, K p K i These are the preset proportional coefficients.

[0109] S1046: In the off-grid state, according to the real-time phase command signal θ srt Control the output current of the converter.

[0110] S1046 can also be described as: In autonomous mode, the converter is controlled by fixed-frequency network configuration according to the real-time phase command signal.

[0111] S1046 includes:

[0112] S10462: Based on the converter's three-phase port voltage signal u from the real-time acquired initial signal of the converter. a u b u c Determine the active current command information of the converter (cmd) Ia and reactive current command information cmd Ir ;

[0113] S10464: According to the real-time phase command signal θ srt For voltage signal u a u b u c After transformation and filtering, the active current component I of the converter output current in the off-grid state is obtained. oa_离网 and the reactive component of current I or_离网 ;

[0114] S10466: According to the converter active current command information cmd Ia and reactive current command information cmd Ir The active current component I of the converter output current in off-grid mode oa_离网 and the reactive component of current I or_离网 The three-phase modulated wave signals xa, xb, and xc in the stationary coordinate system are obtained.

[0115] S10468: Perform pulse width modulation or space vector pulse width modulation on the three-phase modulation wave signals xa, xb, and xc to obtain the control signal Y of the switch, and control the output current of the converter based on the control signal Y.

[0116] In specific implementation, S1046 can be paraphrased as follows: 1)-9):

[0117] 1) The phase signal θ of phase A voltage obtained from the real-time phase-locked loop AU For the three-phase port voltage signal u a u b u c The voltage reactive component U of the converter port voltage is obtained by sequentially applying the Clarke transform and Park transform, followed by filtering with a low-pass filter (cutoff frequency greater than 10Hz and less than 50Hz). or_变流器 .

[0118] 2) Utilize the pre-acquired converter port voltage amplitude command U set (e.g., 311V) minus the real-time port voltage amplitude V 端口 The difference is then proportionally and integrally calculated to obtain the initial converter active current command information cmd. Ia0 .

[0119] Specifically, the converter's port voltage amplitude command U set The method of obtaining it is:

[0120] The first acquisition method is for the remote controller to determine the port voltage amplitude command U at the edge where each converter is located. set Specifically, the remote controller, based on the current topology and line impedance of the isolated area (calculated by S102), calculates the port voltage amplitude command U for each node through power flow. set And distribute it to the edge.

[0121] The second method is to locally adjust the port voltage amplitude command U based on the active power transmitted by the converter. set Specifically, when the converter transmits the command value P of active power... ref When changes occur, the difference in active power command is divided by the phase voltage amplitude information V. 端口 Multiply this value by the average resistive component of the line impedance. (Calculated by S1026), this product term is used as the adjustment amount for the voltage port voltage command. This value is added to the port voltage command U at the previous time (i.e., the previous acquisition cycle, which can be set to sample once per second or per minute). set0 As the new port voltage command information U set :

[0122]

[0123] Among them, P ref0 This is the command value of the active power at the previous moment.

[0124] 3) Convert the reactive component U or_变流器 After negation, perform proportional-integral calculations to obtain the initial converter reactive current command information cmd. Ir0 .

[0125] 4) Regarding cmd Ia0 cmd Ir0 The active current command information (cmd) of the converter is obtained after correction. Ia and reactive current command information cmd Ir The correction process is as follows:

[0126] ①If the initial active current command information is cmd Ia0 and initial reactive current command information cmd Ir0 If the amplitudes are all greater than or equal to k times the rated current of the device (k is a proportionality coefficient between 1.1 and 1.3), then cmd Ia0 The amplitude correction is k times the device's rated current multiplied by the cosine of the pre-obtained target power factor angle, with its sign remaining consistent with the original value; cmd Ir0The amplitude correction is k times the device's rated current multiplied by the sine of the pre-obtained target power factor angle, with the positive and negative signs remaining consistent with those before correction.

[0127] ②If the initial active current command information is cmd Ia0 Initial reactive current command information cmd Ir0 If any amplitude is less than k times the rated current of the device, then the active current command information cmd is calculated. Ia0 and reactive current command information cmd Ir0 The amplitude of the synthesized total current command information.

[0128] ③If cmd Ir0 If the amplitude of the synthesized total current command information is less than or equal to k times the device's rated current (k is a proportionality coefficient between 1.1 and 1.3), then no adjustment to the cmd is required. Ia0 and reactive current command information cmd Ir0 Processing, directly using cmd Ia0 As cmd Ia 1. cmd Ir0 As cmd Ir .

[0129] ④ If the amplitude of the synthesized total current command information is greater than k times the device's rated current, and cmd Ia0 The amplitude is less than k times the rated current, cmd Ir0 k times greater than the rated current: only for cmd Ir0 Make corrections to obtain the corrected cmd. Ir cmd Ir The absolute value is the square root of the difference between two parameters, where the first parameter is the square of k times the device's rated current, and the second parameter is cmd. Ia0 The square of; cmd Ir The sign of the phase current is determined by the phase relationship between the phase voltage and the phase current. If the phase voltage leads the phase current, the converter generates inductive reactive current; otherwise, it generates capacitive reactive current.

[0130] ⑤ If the amplitude of the synthesized total current command information is greater than k times the device's rated current, cmd Ia0 The amplitude is greater than k times the rated current, cmd Ir0 If the amplitude is less than k times the rated current, then the correction process in ① is executed.

[0131] ⑥ If the amplitude of the synthesized total current command information is greater than k times the device's rated current, cmd Ia0 amplitude, cmd Ir0 If the amplitude of each current is less than k times the rated current, then the correction process in ④ is executed.

[0132] 5) The converter dynamic phase command signal θ obtained based on S1044 srt For the three-phase output current signal u a u b u c The active current component I of the converter output current in the autonomous (i.e., off-grid) state of the distribution network is obtained by sequentially applying the Clark transform and Park transform, followed by filtering with a low-pass filter (cutoff frequency greater than 10Hz and less than 50Hz). oa_离网 and the reactive component of current I or_离网 .

[0133] 6)cmd Ia Subtract I oa_离网 The direct-axis signal u of the modulation wave command is obtained by performing a PI (proportional-integral) operation on the difference. d1 .

[0134] 7)cmd Ir Subtract I or_离网 The cross-axis signal u of the modulation wave command is obtained by performing a PI (proportional-integral) operation on the difference. q1 .

[0135] 8) For the direct-axis signal u of the modulated wave d1 and cross-axis signal u q1 After undergoing inverse Parker transform and inverse Clarke transform respectively, the three-phase modulated wave signals xa, xb, and xc in the stationary coordinate system are obtained.

[0136] 9) Pulse width modulation (PWM) or space vector pulse width modulation (SVM) is applied to the three-phase modulation wave signals xa, xb, and xc to obtain the control signal Y of the switch. Based on the control signal Y, the drive circuit is adjusted to complete the control of the switching transistor in the converter.

[0137] In addition, S104 includes the following steps for determining whether a fault has occurred in the distribution network:

[0138] If the real-time converter port phase voltage amplitude information V 端口 If the voltage exceeds the preset first voltage threshold, a fault is considered to have occurred in the distribution network; if the real-time acquired converter port phase voltage amplitude information V 端口 >The preset second voltage threshold is considered to indicate that no fault has occurred in the distribution network; if the converter port phase voltage amplitude information V 端口 Between the preset first voltage threshold and the preset second voltage threshold, the angle sum θ is calculated. SUM If the sum of angles θ SUMIf the voltage is not within the preset summation threshold range, the distribution network is considered to have a fault; otherwise, the distribution network is considered not to have a fault. Wherein, the first voltage threshold is less than the second voltage threshold.

[0139] In S104, the sum of angles θ is calculated. SUM The steps include:

[0140] A preset amount of reactive power is injected into the distribution network (at which point the operating state of the distribution network changes), and the voltage amplitude V at the port after the reactive power injection is calculated. 端口 and the phase signal θ of phase A voltage AU Determine θ SUM .

[0141] In practical implementation, the steps in S104 for determining whether a fault has occurred in the distribution network can be summarized as follows:

[0142] Based on the real-time acquired phase signal θ of phase A voltage AU Real-time acquisition of port phase voltage amplitude information V 端口 Islanding detection is performed. When certain conditions are met, a fault is considered to have occurred. At this time, the distribution network switches to islanding autonomy. Otherwise, the grid connection control operation shown in step S106 is executed.

[0143] The steps in S104 to determine whether a fault has occurred in the distribution network can also be summarized as 1)-3):

[0144] 1) When the port voltage amplitude V 端口 If the voltage is less than 80% of its rated value (generally 311V for low-voltage distribution networks), then the distribution network is considered to have a fault.

[0145] 2) When the port voltage amplitude V 端口 If the value is greater than 90% of its rated value, the distribution network is considered to be without fault.

[0146] 3) When the port voltage amplitude V 端口 When the angle is 80%-90% of the rated value, calculate the sum of the angles θ. SUM Then determine whether a malfunction has occurred.

[0147] ① Based on the existing transmission power, a certain amount of reactive power Q is injected into the distribution network using a current loop controller. ref :

[0148] Q ref =Q ref +A1×P ref 0.8V ref ≤V 端口 ≤0.9V ref Formula 13;

[0149] Among them, Vref For its rated value, P ref Q is the current active power command value. ref A1 is the current reactive power command value, and A1 is the injection proportional coefficient, which can be 0.1.

[0150] ②Injected reactive power Q ref Then, the phase difference between the output phases of two adjacent control cycles is calculated (the first phase-locked loop that meets this condition is defined as i). The difference is then summed for a specified number of consecutive times to obtain the angle sum θ. SUM The consecutive specified number is the controller's control frequency f divided by 50:

[0151]

[0152] Where, θ AU,i The phase is calculated for the i-th control cycle, where i is a natural number. When the port voltage is less than 90% of the rated value, the corresponding value of i is 1.

[0153] If the θ SUM If the summation value is outside the preset threshold range, a fault is considered to have occurred in the distribution network; if it is within the preset threshold range, no fault is considered to have occurred in the distribution network. This detection process is a rolling test process, that is, continuously detecting V. 端口 When the value is between 80% and 90% of the rated value, Formulas 13 and 14 are executed.

[0154] Specifically, if θ SUM A fault is considered to have occurred if the reading is less than 6.157 rad or greater than 6.409 rad.

[0155] In summary, when the port voltage amplitude V 端口 Less than 80% of the rated value or θ SUM If the value is outside the preset threshold range, the distribution network is considered to have experienced a fault; otherwise, the distribution network is considered not to have experienced a fault.

[0156] The following is a detailed introduction to S106:

[0157] Specifically, S106 includes:

[0158] S1062: Based on the current operating status of the converter's active power P ref and reactive power Q ref Determine the active current command information of the converter (cmd) Ia ′ and reactive current command information cmd Ir ′;

[0159] S1064: Based on the current phase-locked loop A-phase voltage phase signal θ AU For the current three-phase output current signal ioa i ob i oc Transformation and filtering are performed to obtain the active current component I of the converter output current under grid-connected conditions. oa_并网 and the reactive component of current I or_并网 ;

[0160] S1066: According to the converter active current command information cmd Ia ′ and reactive current command information cmd Ir The active current component I of the converter output current under grid-connected conditions. oa_并网 and the reactive component of current I or_并网 The three-phase modulated wave signals xa', xb', and xc' in the stationary coordinate system are obtained.

[0161] S1068: Perform pulse width modulation or space vector pulse width modulation on the three-phase modulation wave signals xa', xb', and xc' to obtain the control signal Y' of the switch, and control the output current of the converter based on the control signal Y'.

[0162] Specifically, S106 can be paraphrased as 1)-7):

[0163] 1) Change the current converter active power command P ref Divide by the amplitude information V of the converter port phase voltage 端口 Multiply the above result by 2 and then divide by 3 to obtain the converter active current command information cmd. Ia ′.

[0164] 2) Change the current converter reactive power command Q ref Divide by the amplitude information V of the converter port phase voltage 端口 Multiply the above result by 2 and then divide by 3 to obtain the converter reactive current command information cmd. Ir ′.

[0165] 3) The phase signal θ of phase A voltage obtained from the real-time phase-locked loop. AU For the three-phase output current signal i oa i ob i oc The active current component I of the converter output current under grid-connected conditions is obtained by sequentially applying the Clarke transform and Park transform, followed by filtering with a low-pass filter (cutoff frequency greater than 10Hz and less than 50Hz). oa_并网 and the reactive component of current I or_并网 .

[0166] 4) cmd Ia ′ minus I oa_并网 The direct-axis signal u of the modulation wave command is obtained by performing a PI (proportional-integral) operation on the difference.d2 .

[0167] 5)cmd Ia ′ minus I or_并网 The cross-axis signal u of the modulation wave command is obtained by performing a PI (proportional-integral) operation on the difference. q2 .

[0168] 6) For the direct-axis signal u of the modulated wave d2 and cross-axis signal u q2 After undergoing inverse Parker transform and inverse Clarke transform respectively, the three-phase modulated wave signals xa', xb', and xc' in the stationary coordinate system are obtained.

[0169] 7) Pulse width modulation (PWM) or space vector pulse width modulation (SVM) is performed on the three-phase modulation wave signals xa', xb', and xc' to obtain the control signal Y' of the switch. Based on the control signal Y', the circuit is driven to complete the control of the switching transistors in the converter.

[0170] In addition, S106 includes the following steps for determining whether the power distribution network has been restored:

[0171] Based on the active current component I of the converter output current under different continuous operating conditions oa Reactive component of current I or A first angle value is determined. If the first angle value is greater than a preset first angle threshold, the count is incremented to obtain a count value. If the first angle value is less than or equal to the preset first angle threshold, the count is reset to zero. When the count value is greater than a preset control threshold, the power distribution network is considered to have resumed power supply.

[0172] Specifically, the active current component I of the converter output current is obtained. oa Reactive component of current I or The steps are the same as in S1028.

[0173] Specifically, the active current component I of the converter output current is continuously collected. oa Reactive component of current I or The quotient is calculated by performing an arctangent operation. If the angle is greater than 0.5 radians, the count is incremented to obtain a count value N. If the angle is less than 0.45 radians, the count value is reset to zero. When the count value N exceeds the control cycle / 500, the power distribution network is considered to have resumed power supply; otherwise, the power distribution network is considered not to have resumed power supply.

[0174] if arctan(I or / I oa )>0.5N=N+1 Formula 15;

[0175] if arctan(I or / I oa )<0.45N=0 Formula 16.

[0176] In S106, the steps for determining whether the power distribution network has been restored to power also include:

[0177] The power supply status of the distribution network is determined based on the switch status received by the converter at the common bus of the distribution network.

[0178] Specifically, the switch status at the common bus is transmitted to the converter via remote communication. The switch status is open after a grid fault; it is closed after the grid restores power supply; when the converter receives the information that the switch is closed, it considers that the grid has restored power supply.

[0179] Beneficial effects of the embodiments of the present invention:

[0180] 1. Existing technologies rely on geostationary satellite assistance to achieve fixed-frequency control, but this increases costs. This application, in S1042, uses the converter port phase voltage amplitude information V... 端口 The active voltage component U of the line impedance voltage a and voltage reactive component U r The initial phase command signal θ for global synchronization was determined. s This can also achieve synchronization and reduce costs.

[0181] 2. During the process of grid connection to autonomous or autonomous secondary grid connection, current surge problems may occur. This application can achieve steady-state fixed-frequency control without relying on geostationary satellites (see S1042) and can also perform smooth and flexible switching (see S1044, S1046, S106), which helps to reduce the current stress during the switching transient process.

[0182] 3. The fixed-frequency grid control in this invention can not only get rid of the dependence on satellite timing signals (see S1042), but also realize flexible control of the converter output current phase during the grid-connected to autonomous transition period (see S1044, S1046, S106), which is beneficial to reduce equipment costs and improve equipment operational reliability.

[0183] 4. The technical solution disclosed herein utilizes the phase information output by the phase-locked loop and the internal control algorithm to achieve time synchronization of converters in different regions (see S1042), which can reduce the dependence on communication methods such as satellite time synchronization and help reduce costs.

[0184] 5. During the transient transition from grid connection to autonomous operation, frequency gradient control is adopted to ensure that the phase of the converter output current does not change abruptly and the frequency fluctuation is small during the transient (see S1044, S1046, S106). This helps to reduce the transient stress of the current during the switching transient.

[0185] 6. It can not only enable the distribution network to operate at a constant frequency in an autonomous operation state (see S1044, S1046, S106), but also avoid dependence on timing tools (see S1042), and can also realize flexible switching between grid-connected / autonomous (i.e. off-grid), autonomous and grid-connected.

[0186] 7. By separating the active and reactive components of the line impedance voltage in step S102, it is easier to perform fixed-frequency network control of the converter. S102 is a fundamental and important step. The separation allows for more accurate calculation of the inductive and resistive components of the line impedance, providing a data basis for stabilizing the distribution network.

[0187] 8. In S104, the angle summation value θ is calculated by injecting reactive power. SUM It can more quickly determine whether there is a fault in the power distribution network.

[0188] 9. The correction process of S10462 calculates the active current command information through PI calculation of the voltage amplitude, and adjusts the reactive component U of the converter port voltage. or_变流器 By obtaining the reactive current command information, local reactive power compensation can be achieved using the reactive power output of the converter. At the same time, the active current command information and reactive current command information of the converter are constrained after considering the current stress of the device, so as to balance the active power output of the converter, reactive power compensation (meeting the target power factor) and the long-term reliability of the equipment.

[0189] 10. In S1046, the converter port voltage command U is modified through two modes: remote global controller and converter self-adjustment. set This not only ensures the distributed voltage characteristics in the distribution network, but also enables accurate voltage regulation and facilitates power flow control in autonomous microgrids.

[0190] In S106, calculating the count value N based on dividing the reactive component of the converter output current by the active component can determine whether the power grid has been restored to power supply more quickly and accurately.

[0191] 12. This embodiment improves the power-angle stability and frequency stability issues during autonomous operation of high-proportion distribution substations. On the one hand, it utilizes the phase information output by the phase-locked loop and the internal control algorithm to achieve time synchronization of converters in different areas, reducing dependence on communication methods such as satellite time synchronization and thus reducing costs. On the other hand, during the transient transition from grid connection to autonomous operation, frequency gradient control is adopted to ensure that the phase of the converter output current does not change abruptly and that the frequency fluctuation is small during the transient state. This helps to reduce the transient stress of the current during the switching transient state.

[0192] 13. This embodiment can not only enable the distribution network to operate in an autonomous state at a constant frequency, but also avoid dependence on timing tools, and can also realize flexible switching between grid connection and autonomy, and between autonomy and grid connection.

[0193] Example 3

[0194] This embodiment provides an active power distribution network multi-resource collaborative on-grid and off-grid control device, such as... Figure 3 As shown, the device includes:

[0195] The first control module is used to determine the active voltage component U of the line impedance voltage based on the initial signal from the converter. a and voltage reactive component U r .

[0196] The second control module is used to determine the active voltage component U based on the line impedance voltage if a fault occurs in the distribution network. a and voltage reactive component U r The phase command of the converter output current is synchronously and dynamically adjusted to realize the control of the converter output current in the off-grid state.

[0197] The third control module is used to control the converter output current under grid-connected conditions based on the current operating status if the power distribution network is restored.

[0198] The beneficial effects of the active distribution network multi-resource collaborative and off-grid control device in this embodiment are the same as those in the above embodiments, and will not be repeated in this embodiment.

[0199] Example 4

[0200] Figure 4 This is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention, as shown below. Figure 4 As shown, the electronic device may include at least one processor; and at least one memory communicatively connected to the processor, wherein the memory stores program instructions executable by the processor, and the processor can execute the above-described active power distribution network multi-resource collaborative off-grid control method of the present invention by calling the program instructions.

[0201] Figure 4A block diagram is shown that is suitable for implementing embodiments of the present invention. Figure 4 The electronic device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of the present invention.

[0202] like Figure 4 As shown, the electronic device is represented in the form of a general-purpose computing device. The components of the electronic device may include, but are not limited to: one or more processors 410, memory 430, and communication bus 440 connecting different system components (including memory 430 and processing unit 410).

[0203] Communication bus 440 represents one or more of several bus architectures, including a memory bus or memory controller, a peripheral bus, a graphics acceleration port, a processor, or a local bus using any of the various bus architectures. For example, these architectures include, but are not limited to, Industry Standard Architecture (ISA) buses, MicroChannel Architecture (MAC) buses, Enhanced ISA buses, Video Electronics Standards Association (VESA) local buses, and Peripheral Component Interconnect (PCI) buses.

[0204] Electronic devices typically include a variety of computer-readable media. These media can be any available media that can be accessed by the electronic device, including volatile and non-volatile media, and removable and non-removable media.

[0205] Memory 430 may include computer system readable media in the form of volatile memory, such as random access memory (RAM) and / or cache memory. The electronic device may further include other removable / non-removable, volatile / non-volatile computer system storage media. Memory 430 may include at least one program product having a set (e.g., at least one) of program modules configured to perform the functions of various embodiments of the present invention.

[0206] A program / utility having a set (at least one) of program modules can be stored in memory 430. Such program modules include—but are not limited to—an operating system, one or more application programs, other program modules, and program data. Each or some combination of these examples may include an implementation of a network environment. The program modules typically perform the functions and / or methods described in the embodiments of this invention.

[0207] The processor 410 executes various functional applications and data processing by running programs stored in the memory 430, such as implementing the active power distribution network multi-resource collaborative and off-grid control method described in the embodiments of the present invention.

[0208] Example 5

[0209] This invention provides a non-transitory computer-readable storage medium that stores computer instructions, which cause the computer to execute the active power distribution network multi-resource collaborative and off-grid control method of the above embodiments of this invention.

[0210] The aforementioned computer-readable storage medium may be any combination of one or more computer-readable media. A computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium may be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), or flash memory, optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium may be any tangible medium containing or storing a program that may be used by or in connection with an instruction execution system, apparatus, or device.

[0211] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including—but not limited to—electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, capable of transmitting, propagating, or transmitting programs for use by or in connection with an instruction execution system, apparatus, or device.

[0212] The program code contained on a computer-readable medium may be transmitted using any suitable medium, including—but not limited to—wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0213] Computer program code for performing the operations of embodiments of the present invention can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a Local Area Network (LAN) or a Wide Area Network (WAN), or it can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0214] The foregoing has described specific embodiments of the present invention. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired results. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0215] In the description of the embodiments of the present invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In the embodiments of the present invention, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in the embodiments of the present invention, as well as the features of the different embodiments or examples.

[0216] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of embodiments of the present invention, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0217] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of the invention pertain.

[0218] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0219] It should be noted that the terminals involved in the embodiments of the present invention may include, but are not limited to, personal computers (PCs), personal digital assistants (PDAs), wireless handheld devices, tablet computers, mobile phones, MP3 players, MP4 players, etc.

[0220] In the several embodiments provided in this invention, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0221] Furthermore, in the various embodiments of the present invention, the functional units can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or in the form of hardware plus software functional units.

[0222] The integrated units implemented as software functional units described above can be stored in a computer-readable storage medium. These software functional units, stored in a storage medium, include several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute some steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0223] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for multi-resource coordinated on-grid and off-grid control in an active distribution network, characterized in that, The method includes: S102: Determine the active voltage component of the line impedance voltage based on the converter's initial signal. and voltage reactive component ; S104: If a fault occurs in the distribution network, the active voltage component based on the line impedance voltage... and voltage reactive component The phase command of the converter output current is synchronously and dynamically adjusted to realize the control of the converter output current in the off-grid state; S106: If the power distribution network resumes power supply, the output current of the converter under grid-connected status will be controlled based on the current operating status. S104 includes: S1042: Based on the active voltage component of the line impedance voltage and voltage reactive component Confirm the current phase-locked loop A-phase voltage phase signal Preliminary phase command signal with pre-acquired global synchronization The first phase difference between ; S1044: Based on the first phase difference The phase signal of phase-locked loop A-phase voltage acquired in real time Dynamic adjustment is performed to obtain real-time phase command signals. ; S1046: In the off-grid state, according to the real-time phase command signal Control the output current of the converter.

2. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 1, characterized in that, S102 includes: S1022: Determine the direct-axis component of the converter port voltage under different operating conditions based on the real-time acquired initial signal of the converter. Port voltage quadrature axis component and the direct-axis component of the converter output current Output current quadrature axis component ; S1024: Calculate the difference of the direct-axis components of the port voltage under any two different operating conditions. Port voltage quadrature axis component difference Output current direct-axis component difference Output current quadrature axis component difference ; S1026: Based on the difference of the direct-axis components of the port voltage under any two different operating states Port voltage quadrature axis component difference Output current direct-axis component difference Output current quadrature axis component difference Determine the average resistive component of the line impedance and average sensory component ; S1028: Based on the real-time acquired phase-locked loop A-phase voltage phase signal Determine the active current component of the converter output current and reactive components of current ; S10210: Active current component based on the output current of the converter reactive component of current Average resistive component of line impedance and average sensory component Decompose the line impedance voltage into voltage active components. and voltage reactive component .

3. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 2, characterized in that, S1042 includes: S10422: Real-time calculation of the direct-axis component of the converter port voltage obtained from S1022. and port voltage cross-axis component Determine the phase voltage amplitude information at the converter port ; S10424: Based on the port phase voltage amplitude information The active voltage component of the line impedance voltage and voltage reactive component Determine the phase offset angle ; S10426: Based on the currently acquired fault occurrence time and the preset tracing time interval and the phase offset angle Obtain the initial phase command signal for global synchronization. ; S10428: Preliminary phase command signal for global synchronization Phase signal of phase-locked loop A-phase voltage at the current moment The first phase difference is obtained by subtraction. .

4. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 2, characterized in that, S1044 includes: S10442: If the first phase difference <The preset first phase threshold is based on the first gradient frequency. Preset retelling time interval and real-time phase-locked loop A-phase voltage phase signal Obtain real-time phase command signal Wherein, the first gradient frequency It is obtained by dynamic adjustment based on proportional-integral calculation; S10444: If the first phase difference If the first phase threshold is greater than or equal to the preset value, then the second gradient frequency is used. Preset retelling time interval and real-time phase-locked loop A-phase voltage phase signal Obtain real-time phase command signal ; wherein, the second gradient frequency It is obtained by dynamic adjustment based on proportional-integral calculation.

5. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 2, characterized in that, S1046 includes: S10462: Based on the converter's three-phase port voltage signal from the real-time acquired initial signal of the converter. Determine the active current command information of the converter and reactive current command information ; S10464: According to the real-time phase command signal For voltage signals After transformation and filtering, the active current component of the converter output current in the off-grid state is obtained. and reactive component of current ; S10466: Based on the active current command information of the converter and reactive current command information The active current component of the converter output current in off-grid mode and reactive component of current The three-phase modulated wave signals xa, xb, and xc in the stationary coordinate system are obtained. S10468: Perform pulse width modulation or space vector pulse width modulation on the three-phase modulation wave signals xa, xb, and xc to obtain the control signal Y of the switch, and control the output current of the converter based on the control signal Y.

6. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 1, characterized in that, In S104, the steps for determining whether a fault has occurred in the distribution network include: If the converter port phase voltage amplitude information is acquired in real time A voltage threshold less than the preset first voltage threshold is considered a fault in the distribution network. If the converter port phase voltage amplitude information is acquired in real time The preset second voltage threshold is considered to indicate that no fault has occurred in the distribution network; If the converter port phase voltage amplitude information Between the preset first voltage threshold and the preset second voltage threshold, the angle summation value is calculated. If the sum of the angles If the voltage is not within the preset summation threshold range, the distribution network is considered to have a fault; otherwise, the distribution network is considered not to have a fault. Wherein, the first voltage threshold is less than the second voltage threshold.

7. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 6, characterized in that, In S104, the sum of angles is calculated. The steps include: A preset amount of reactive power is injected into the distribution network, and the voltage amplitude at the ports after the reactive power injection is calculated. and A-phase voltage phase signal Determine the sum of angles .

8. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 2, characterized in that, In S106, the steps for determining whether the power distribution network has been restored include: Based on the active current component of the converter output current under different continuous operating conditions reactive component of current Determine a first angle value. If the first angle value is greater than a preset first angle threshold, start accumulating a count to obtain a count value. If the first angle value is less than or equal to the preset first angle threshold, clear the count value to zero. When the count value exceeds the preset control threshold, the power distribution network is considered to have resumed power supply.

9. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 8, characterized in that, In S106, the steps for determining whether the power distribution network has been restored to power also include: The power supply status of the distribution network is determined based on the switch status received by the converter at the common bus of the distribution network.

10. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 1, characterized in that, S106 includes: S1062: Based on the active power of the converter under the current operating condition. and reactive power Determine the active current command information of the converter and reactive current command information ; S1064: Based on the current phase-locked loop A-phase voltage phase signal The three-phase output current signal in the current initial signal Transformation and filtering processes are performed to obtain the active current component of the converter output current under grid-connected conditions. and reactive component of current ; S1066: Based on the active current command information of the converter and reactive current command information The active current component of the converter output current under grid-connected conditions and reactive component of current The three-phase modulated wave signals xa', xb', and xc' in the stationary coordinate system are obtained. S1068: Perform pulse width modulation or space vector pulse width modulation on the three-phase modulation wave signals xa', xb', and xc' to obtain the control signal Y' of the switch, and control the output current of the converter based on the control signal Y'.

11. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 1, characterized in that, S104 includes: If no fault occurs in the distribution network, then execute S106.

12. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 1, characterized in that, S106 includes: If the power distribution network has not been restored, then S104 shall be executed.

13. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 5, characterized in that, S10462 includes: S104622: Based on the phase signal of phase A voltage of the phase-locked loop. For the three-phase port voltage signal of the converter The voltage reactive component of the converter port voltage is obtained by using Clarke transform, Park transform, and filtering. ; S104624: Based on the pre-acquired converter port voltage amplitude command and converter port voltage amplitude Determine the initial active current command information of the converter. ; S104626: Voltage reactive component of converter port voltage After taking the negative value, a proportional-integral operation is performed to obtain the initial converter reactive current command information. ; S104628: Initial converter active current command information Initial converter reactive current command information The converter active current command information is obtained by making corrections separately. and reactive current command information .

14. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 13, characterized in that, In S104624, the command to obtain the port voltage amplitude of the converter is... The steps include: Based on the current active power command value The active power command value at the previous moment The converter port voltage amplitude command from the previous moment Real-time acquisition of converter port phase voltage amplitude information Average resistive component of line impedance Command to determine the port voltage amplitude of the converter ; or, Based on the current topology and line impedance of the off-grid area, the port voltage amplitude command of the converter in the distribution network is obtained through power flow calculation. .

15. An active power distribution network multi-resource collaborative on-grid and off-grid control device, characterized in that, The device includes: The first control module is used to determine the active voltage component of the line impedance voltage based on the initial signal from the converter. and voltage reactive component ; The second control module is used to determine the active voltage component based on the line impedance voltage in the event of a fault in the distribution network. and voltage reactive component The phase command of the converter output current is synchronously and dynamically adjusted to realize the control of the converter output current in the off-grid state; The third control module is used to control the converter output current under grid-connected conditions based on the current operating status if the power distribution network is restored. The second control module is further configured to: determine the first phase difference between the current phase-locked loop A-phase voltage phase signal and the pre-acquired global synchronization preliminary phase command signal based on the active and reactive voltage components of the line impedance voltage; dynamically adjust the real-time acquired phase-locked loop A-phase voltage phase signal based on the first phase difference to obtain a real-time phase command signal; and control the output current of the converter according to the real-time phase command signal in the off-grid state.

16. An electronic device, characterized in that, include: At least one processor; as well as At least one memory communicatively connected to the processor, wherein: The memory stores program instructions that can be executed by the processor, and the processor can execute the active power distribution network multi-resource coordination and off-grid control method as described in any one of claims 1 to 14 by calling the program instructions.

17. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that cause the computer to perform the active power distribution network multi-resource coordination and off-grid control method as described in any one of claims 1 to 14.

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