Multi-resource collaborative grid-connected and off-grid control method and device for active power distribution network and storage medium

Abstract

The invention provides a multi-resource cooperative grid-connected and off-grid control method and device for an active power distribution network and a storage medium. The method comprises the following steps: determining a voltage active component Ua and a voltage reactive component Ur of line impedance voltage according to an initial signal of a converter; if the power distribution network has a fault, synchronously and dynamically adjusting the phase instruction of the output current of the converter based on the voltage active component Ua and the voltage reactive component Ur of the line impedance voltage to realize the control of the output current of the converter in an off-grid state; and if the power distribution network recovers power supply, controlling the output current of the converter in the grid-connected state based on the current operation state. According to the invention, dependence on satellite time service signals can be eliminated, flexible control of the output current phase of the converter during the period from grid connection to autonomy can be realized, the cost of equipment can be reduced, and the operation reliability of the equipment can be improved.

Description

Technical Field

[0001] The present invention relates to the field of power grid control technology, and in particular to a method, device and storage medium for coordinated on-grid and off-grid control of multiple resources in an active distribution network. Background Art

[0002] With the increasing penetration rate of distributed power sources and energy storage devices in distribution networks, how to ensure stable power supply of distribution networks under external unstable conditions has become a technical problem that needs to be solved urgently.

[0003] Existing technologies for autonomous distribution networks can be categorized into two types, based on their operating frequency characteristics: virtual synchronous generator-like networking and fixed-frequency networking. The former is prone to transient current surges when connected to complex control systems or when loads fluctuate dramatically; the latter relies on satellite timing synchronization, increasing device costs. Summary of the Invention

[0004] Based on this, the present application provides a method, device and storage medium for collaborative on-grid and off-grid control of multiple resources in an active distribution network, which can ensure the stability of the output current of the distribution network converter under complex off-grid and on-grid control conditions and when the load fluctuates violently without relying on satellites.

[0005] In a first aspect, an embodiment of the present invention provides a method for controlling multi-resource coordination and disconnection of an active power distribution network, the method comprising: S102: determining the active voltage component U of the line impedance voltage according to the initial signal of the converter. a and voltage reactive component U r ; 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 Synchronously and dynamically adjust the phase command of the converter output current to achieve control of the converter output current in the off-grid state; S106: If the distribution network resumes power supply, control of the converter output current in the grid-connected state is achieved 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 states based on the initial signal of the converter obtained in real time d , port voltage quadrature axis component u q And the converter output current direct axis component i 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 states d , port voltage quadrature axis component difference Δu q , output current direct axis component difference Δi d , output current quadrature axis component difference Δi q; S1026: According to 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 , output current direct axis component difference Δi d , output current quadrature axis component difference Δi q Determine the average resistive component of the line impedance and average perceptual component S1028: Based on the real-time acquired phase-locked loop A phase voltage phase signal θ AU Determine the active component I of the converter output current oa and the reactive component of current I or ; S10210: Based on the active current component I of the output current of the converter oa , reactive component of current I or , the average resistive component of the line impedance and average perceptual component Split the line impedance voltage into the active voltage component U a and voltage reactive component U r .

[0007] Further, S104 includes: S1042: according to the voltage active component U of the line impedance voltage a and voltage reactive component U r Confirm the current phase-locked loop A phase voltage phase signal θ AU The preliminary phase command signal θ obtained in advance and synchronized with the global s The first phase difference between S1044: Based on the first phase difference The phase-A voltage phase signal θ obtained in real time AU Perform dynamic adjustment to obtain real-time phase command signal θ srt ; S1046: In the off-grid state, according to the real-time phase command signal θ srt Controls the output current of the converter.

[0008] Furthermore, S1042 includes: S10422: real-time acquisition of the converter port voltage direct axis component u according to S1022 d and the quadrature axis component u of the port voltage q Determine the phase voltage amplitude information V of the converter port 端口 ; S10424: According to 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 retrospective time interval Δt and the phase offset angle Get the preliminary phase command signal θ for global synchronization s ; S10428: The preliminary phase instruction signal θ of global synchronization s and the phase-locked loop A phase voltage phase signal θ at the current moment AU The first phase difference is obtained by subtracting

[0009] Further, S1044 includes: S10442: If the first phase difference <preset first phase threshold, then based on the first gradual frequency f a , the preset recall 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 is obtained by dynamic adjustment based on proportional integral operation; S10444: if the first phase difference ≥ the preset first phase threshold, then based on the second gradual frequency f b , the preset recall 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 operation.

[0010] Furthermore, S1046 includes: S10462: according to the converter three-phase port voltage signal u in the converter initial signal obtained in real time a 、u b 、u c Determine the converter active current command information 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 Perform conversion and filtering to obtain the active current component I of the converter output current in the off-grid state. oa_离网 and the reactive component of current I or_离网 ; 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 the off-grid state oa_离网 and the reactive component of current I or_离网Obtain three-phase modulated wave signals xa, xb, and xc in a stationary coordinate system; S10468: Perform pulse width modulation or space vector pulse width modulation on the three-phase modulated wave signals xa, xb, and xc to obtain a switch control signal Y, and control the output current of the converter based on the control signal Y.

[0011] Furthermore, in S104, the step of determining whether a fault occurs in the distribution network includes: if the real-time acquired converter port phase voltage amplitude information V 端口 < the preset first voltage threshold, it is considered that the distribution network has failed; if the real-time obtained converter port phase voltage amplitude information V 端口 > the preset second voltage threshold, it is considered that the distribution network has not failed; 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 value θ is calculated SUM , if the angle sum θ SUM If it is not within the preset sum threshold range, it is considered that the distribution network has failed, otherwise it is considered that the distribution network has not failed; wherein, the first voltage threshold is less than the second voltage threshold.

[0012] Furthermore, in S104, the angle sum value 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 is injected 端口 and A phase voltage phase signal θ AU Determine the angle sum θ SUM .

[0013] Furthermore, in S106, the step of judging whether the power distribution network has resumed power supply includes: determining the active current component I of the output current of the converter under different continuous operating conditions; oa , reactive component of current I or Determine a first angle value. If the first angle value is greater than a preset first angle threshold, start accumulating the 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. When the count value is greater than the preset control threshold, it is considered that the distribution network has restored power supply.

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

[0015] Furthermore, S106 includes: S1062: according to the active power P of the converter in the current operating state ref and reactive power Q ref Determine the converter active current command information cmd Ia' and reactive current command information cmd Ir '; S1064: According to 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 After transformation and filtering, the active current component I of the converter output current in the grid-connected state is obtained. oa_并网 and the reactive component of current I or_并网 ; 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 in the grid-connected state oa_并网 and the reactive component of current I or_并网 Obtain three-phase modulated wave signals xa', xb', and xc' in a 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 a switch control signal Y', and control the output current of the converter based on the control signal Y'.

[0016] Furthermore, S104 includes: if no failure occurs in the distribution network, executing S106.

[0017] Furthermore, S106 includes: if the power distribution network has not restored power supply, executing S104.

[0018] Further, S10462 includes: S104622: according to the phase signal θ of the A phase voltage of the phase locked loop AU The voltage signal u of the three-phase port of the converter a 、u b 、u c Clarke transform, Park transform and filtering are used to obtain the voltage reactive component U of the converter port voltage. or_变流器 ; S104624: According to the pre-acquired converter port voltage amplitude instruction U set and the converter port voltage amplitude V 端口 Determine the initial converter active current command information cmd Ia0 ; S104626: Reactive voltage component U of the converter port voltage or_变流器 After taking the negative, perform proportional plus integral operation 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 Correct the converter active current command information cmd IaAnd reactive current command information cmd Ir .

[0019] Furthermore, in S104624, the port voltage amplitude instruction U of the converter is obtained. 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 at the previous moment set0 , Real-time acquired converter port phase voltage amplitude information V 端口 , the average resistive component of the line impedance Determine the converter's port voltage amplitude command U set Alternatively, based on the current off-grid area topology and line impedance, the port voltage amplitude command U of the converter in the distribution network is obtained by flow calculation. set .

[0020] In a second aspect, an embodiment of the present invention provides a multi-resource coordinated on-grid and off-grid control device for an active distribution network, the device comprising: a first control module for determining the active voltage component U of the line impedance voltage according to the initial signal of the converter; a and voltage reactive component U r The second control module is used for if the distribution network fails, the voltage active component U based on the line impedance voltage a and voltage reactive component U r Synchronously and dynamically adjust the phase instruction of the converter output current 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 in the grid-connected state based on the current operating status if the distribution network resumes power supply.

[0021] In a third aspect, an embodiment of the present invention provides an electronic device, comprising: 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 calls the program instructions to execute the above-mentioned active distribution network multi-resource coordination and off-grid control method.

[0022] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and the computer instructions enable the computer to execute the above-mentioned active 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] The embodiment of the present invention provides a method, device and storage medium for controlling multi-resource coordination and disconnection of an active power distribution network, including: determining the active voltage component U of the line impedance voltage according to 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 a and voltage reactive component U r The inverter phase is dynamically adjusted synchronously to control the inverter output current in the off-grid state. If the distribution network resumes power supply, the inverter output current is controlled in the grid-connected state based on the current operating state. This application not only eliminates the dependence on satellite timing signals, but also enables flexible control of the inverter output current phase during the transition from grid connection to autonomy, which helps reduce equipment costs and improve equipment operational reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A flow chart of a method for collaborative on-grid and off-grid control of multiple resources in an active distribution network provided for the implementation of the present invention;

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

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

[0028] Figure 4 A schematic diagram of an electronic device for multi-resource coordinated and off-grid control of an active power distribution network provided for the implementation of the present invention. DETAILED DESCRIPTION

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

[0030] With the increasing penetration of distributed power sources and energy storage devices in distribution networks, local power balancing is becoming increasingly easier. These networks can restore power to local loads in the form of planned islands or microgrids when the main grid is down. This is crucial for protecting against natural disasters and war damage, and for improving power supply reliability.

[0031] Island systems with a high proportion of renewable energy and power electronic devices have a low inertia and no longer possess the electromechanical characteristics of traditional synchronous machines. Networking technology is required to achieve frequency and voltage support for autonomous distribution networks. Based on the operating frequency characteristics of autonomous distribution networks, there are two types of network construction technologies: virtual synchronous machine-like network construction and fixed-frequency network construction. The former is difficult to avoid power-angle stability and frequency stability issues when the load fluctuates violently, is difficult to plug and play, and is complex to implement in interconnected control across multiple substations and prone to transient current shocks. The latter mostly uses satellite-based timing synchronization technology. Although it can achieve fixed-frequency operation and avoid frequency deviations in steady state, it relies on timing synchronization tools, which increases the cost of the device.

[0032] Example 1

[0033] like Figure 1 As shown, this embodiment proposes a method for controlling multi-resource coordination and on-grid disconnection in an active distribution network, including:

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

[0035] 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 achieve 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 is controlled in the grid-connected state based on the current operating state.

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

[0038] S102-106 can be paraphrased as follows: the converter collects and processes the three-phase voltage signal and three-phase current of its grid connection point; operates on the collected phase voltage signal and current signal of the converter under different working conditions, and calculates the line impedance from the converter to the common bus (the impedance is split into the voltage active component U a and voltage reactive component U r ); further calculate and record the A-phase voltage phase and the voltage phase deviation angle of the phase relative to the common bus; calculate the phase voltage amplitude and phase information to determine whether an AC fault has occurred. If a fault occurs, the time synchronization of each distributed power converter is achieved by relying on the A-phase voltage phase and voltage phase deviation angle recorded before the fault, and the active and reactive current command signals obtained by closed-loop control of the port voltage amplitude are used to achieve fixed-frequency network control of the energy storage converter, and then determine whether the power grid has restored power supply based on the phase difference of the phase voltage and phase current; when no fault occurs or the power grid has restored power supply, the output current of the converter is controlled in the grid-following mode. The fixed-frequency network control in this embodiment can not only get rid of the dependence on satellite timing signals, but also achieve flexible control of the converter output current phase during the transition from grid connection to autonomy, which is conducive to reducing equipment costs and improving equipment operation reliability.

[0039] The embodiment of the present invention provides a method, device and storage medium for controlling multi-resource coordination and disconnection of an active power distribution network, including: determining the active voltage component U of the line impedance voltage according to 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 a and voltage reactive component U r The inverter phase is dynamically adjusted synchronously to control the inverter output current in the off-grid state. If the distribution network resumes power supply, the inverter output current is controlled in the grid-connected state based on the current operating state. This application not only eliminates the dependence on satellite timing signals, but also enables flexible control of the inverter output current phase during the transition from grid connection to autonomy, which helps reduce equipment costs and improve equipment operational reliability.

[0040] Example 2

[0041] This embodiment is a specific explanation of the first embodiment. Figure 2 shown.

[0042] S102: According to the initial signal of the converter (ie Figure 2 The active voltage component U of the line impedance voltage is determined by the processed signal a and voltage reactive component U r (Right now Figure 2 The line impedance from the converter to the common bus).

[0043] 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 The phase command of the converter output current is adjusted synchronously and dynamically, 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 network control).

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

[0045] S104 includes: if no fault occurs in the distribution network, executing S106.

[0046] S106: If the distribution network resumes power supply, the output current of the converter is controlled in the grid-connected state based on the current operating state (i.e. Figure 2 The converter adopts grid-following control to achieve closed-loop control of the output current).

[0047] S106 includes: if the power distribution network has not restored power supply, executing S104.

[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 states based on the initial signal of the converter obtained in real time d , port voltage quadrature axis component u q And the converter output current direct axis component i d , output current quadrature-axis component i q .

[0051] Specifically, the initial signal of the converter includes but is not limited to the three-phase voltage signal u of each converter grid connection point. a 、u b 、u c , three-phase output current signal i oa 、i ob 、i oc , where the current flows into the converter in the positive direction. 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. Different transmission powers produce different initial signals. To make the data more accurate, the initial signals may be collected multiple times at 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 , output current direct axis component difference Δi d , output current quadrature axis component difference Δi q .

[0054] S1026: Based on the direct axis component difference Δu of the port voltages under any two different operating states d , port voltage quadrature axis component difference Δu q , output current direct axis component difference Δi d , output current quadrature axis component difference Δi q Determine the average resistive component of the line impedance and average perceptual component

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

[0056] S10210: Active current component I based on the output current of the converter oa , reactive component of current Ior , the average resistive component of the line impedance and average perceptual component Split the line impedance voltage into the active current component U a and the reactive component of current U r .

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

[0058] 1) Each converter uses its own controller to spontaneously generate a phase signal θ with a fixed frequency of 50Hz F ;

[0059] 2) Based on the obtained phase signal θ F , collect the three-phase voltage signal u a 、u b 、u c Clarke transform and Park transform are used in sequence, and then filtered through a low-pass filter (cut-off frequency is greater than 10Hz and less than 50Hz) to obtain the direct axis component u of the converter port voltage. d and the quadrature 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 Clarke transform and Park transform are used in sequence, and then filtered through a low-pass filter (cut-off frequency is greater than 10Hz and less than 50Hz) to obtain the direct axis component i of the converter output current. d and the quadrature axis component i q ;

[0061] 4) 10ms interval (when the output power changes, generally half of the power frequency cycle d andi q (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 of the output current i d Or the quadrature axis component i q When the change in the last recorded value exceeds 10% of the last moment value, it is considered that the transmission power has changed; by judging the direct axis and quadrature axis components u of multiple groups of converter port voltages and output currents, d 、u q 、i d 、i q and record it in the memory.

[0062] Different operating states correspond to different transmission powers. Under different transmission powers, the direct axis component u of the converter port voltage is d , quadrature axis component u q , the direct axis component of the output current i d , quadrature axis component i q , phase signal θ F , three-phase voltage signals, three-phase output current signals and other data will change.

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

[0064] Using the direct axis components u of the two port voltages d The difference of the direct axis component of the port voltage is obtained by subtracting △u d , using the two-port voltage quadrature component u q The difference of the quadrature axis component of the port voltage is obtained by subtracting △u q ; Using the direct axis components i of the two sets of output currents in corresponding order d The direct axis component difference of the output current is obtained by making a difference △i d , using the quadrature axis components i of the two sets of output currents in corresponding order q The difference of the quadrature axis component of the output current is obtained by making a difference △i q ; Using the direct axis component difference △i of the output current d The square of the output current plus the quadrature component difference △i q The square of the output current quadrature and direct axis components is obtained by:

[0065]

[0066] The direct axis component difference of the port voltage △u d Multiply the direct axis component difference of the output current △i d , the quadrature axis component difference of the port voltage △u q Multiply by the quadrature axis component difference △i of the output current q , add the above two values ​​and divide the sum by the sum of the squares of the difference between the quadrature and direct axis components of the output current After negating this value, we get the resistive component R of the line impedance;

[0067]

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

[0069]

[0070] 6) Take two different combinations of the direct-axis and quadrature-axis components of the converter port voltage and output current, repeat the calculation, and obtain the resistive component R and inductive component value X of the line impedance of at least three groups. L , calculate the average and get the average resistive component of the line impedance and average perceptual component

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

[0072] Specifically, the phase signal θ of the A phase voltage obtained by the phase-locked loop is AU , for the three-phase output current signal i oa 、i ob 、i oc Clarke transform and Park transform are used in sequence, and then filtered through a low-pass filter (cut-off frequency is greater than 10Hz and less than 50Hz) to obtain the active current component I of the converter output current. oa and the reactive component of current I or .

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

[0074] The first sub-item is the active component of the converter output current I oa and the average inductive component of the line impedance Z The product of

[0075] The second sub-item is the reactive component of the converter output current I or and the average resistive component of the line impedance The product of

[0076]

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

[0078] The first sub-item is the active component of the converter output current I oa and the average resistive component of the line impedance The product of

[0079] The second sub-item is the reactive component of the output current of the step converter Ior Average perceptual component The product of

[0080]

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

[0082] S104 includes:

[0083] S1042: Calculate the active voltage component U of the line impedance voltage according to the voltage a and voltage reactive component U r Confirm the current phase-locked loop A phase voltage phase signal θ AU The preliminary phase command signal θ obtained in advance and synchronized with the global s The first phase difference between (Right now Figure 2 voltage phase deviation angle).

[0084] S1042 includes:

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

[0086] Specifically, according to the direct axis component u of the converter port voltage obtained in real time d and the quadrature axis component u q , add the square of the direct axis component and the square of the quadrature axis component, and take the square root of the sum to get the amplitude information of the phase voltage at the converter port V 端口 Under different operating conditions, the corresponding 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 Among them, arctan is the inverse tangent calculation;

[0088]

[0089] S10426: Based on the currently acquired fault occurrence time, the preset retrospective time interval Δt and the phase offset angle Get the preliminary phase command signal θ for global synchronization s .

[0090] S10426 includes: according to the time when the fault occurs, tracing back a certain time interval Δt (generally not less than 100ms), setting the time as zero, and taking the phase of the voltage of phase A at zero time θ AU The voltage phase offset angle calculated by S10424 The difference between the former and the latter is taken as the initial phase θ0, and then θ is calculated. s :

[0091]

[0092] Wherein, Δt is the preset tracing time interval, and the time unit is second.

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

[0094]

[0095] S1044: Based on the first phase difference The phase-A voltage phase signal θ obtained in real time AU Perform dynamic adjustment to obtain real-time phase command signal θ srt .

[0096] S1044 includes:

[0097] S10442: If the first phase difference <preset first phase threshold, then based on the first gradual frequency f a and the preset recall 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 operation;

[0098] S10444: If the first phase difference ≥ the preset first phase threshold, then based on the second gradual frequency f b and the preset recall 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 operation.

[0099] More specifically, S1044 includes:

[0100] 1) If the phase difference 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 50.1 Hz, and the dynamic adjustment amount is a PI (proportional plus integral) operation of the phase angle difference. The proportional coefficient and the integral coefficient ensure that the dynamic adjustment amount of the frequency is less than 0.1 Hz, and the gradual frequency in the steady state is 50 Hz.

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

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

[0105] The gradient frequency f b The initial value is 49.9Hz, and the dynamic adjustment amount is the PI (proportional plus integral) operation of (phase angle difference minus 2*pi). The proportional coefficient and integral coefficient ensure that the dynamic adjustment amount of the frequency is less than 0.1Hz, and the gradual frequency in steady state is 50Hz; the dynamic adjustment amount of the frequency is less than 0.1Hz, and if it is greater than 0.1Hz, it is limited.

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

[0107]

[0108] Among them, K p , K i are the preset scaling factors respectively.

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

[0110] S1046 can be further stated as: in the autonomous state, performing fixed-frequency networking control on the converter according to the real-time phase instruction signal.

[0111] S1046 includes:

[0112] S10462: Based on the converter three-phase port voltage signal u in the converter initial signal obtained in real time a 、u b 、u c Determine the converter active current command information 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 Perform conversion and filtering to obtain the active current component I of the converter output current in the off-grid state. 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 the off-grid state oa_离网 and the reactive component of current I or_离网 Obtain the three-phase modulated wave signals xa, xb, and xc in the stationary coordinate system;

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

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

[0117] 1) The phase signal θ of the A phase voltage obtained by the real-time phase-locked loop AU , for the three-phase port voltage signal u a 、u b 、u c Clarke transform and Park transform are used in sequence, and then filtered through a low-pass filter (cut-off frequency is greater than 10Hz and less than 50Hz) to obtain the voltage reactive component U of the converter port voltage. or_变流器 .

[0118] 2) Using the pre-acquired converter port voltage amplitude command U set (e.g. 311V) minus the real-time port voltage amplitude V 端口 , perform proportional and integral operations on the difference to obtain the initial converter active current command information cmd Ia0 .

[0119] Specifically, the converter port voltage amplitude command U set The way to obtain is:

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

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

[0122]

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

[0124] 3) The reactive component U or_变流器 After taking the negative, perform proportional plus integral operation on it to obtain the initial converter reactive current command information cmd Ir0 .

[0125] 4) cmd Ia0 、cmd Ir0 Correction is performed to obtain the converter active current command information cmd Ia And reactive current command information cmd Ir , the correction process is as follows:

[0126] ① If the initial active current command information cmd Ia0 And initial reactive current command information cmd Ir0 The amplitude of the device is greater than or equal to k times the rated current of the device (k is a proportional coefficient between 1.1 and 1.3), then cmd Ia0 The amplitude of is corrected to k times the rated current of the device multiplied by the cosine value of the target power factor angle obtained in advance, and its positive and negative signs are consistent with those before correction; cmd Ir0The amplitude correction is k times the rated current of the device multiplied by the sine value of the pre-acquired target power factor angle, and its positive and negative signs remain the same as before correction.

[0127] ② If the initial active current command information cmd Ia0 , initial reactive current command information cmd Ir0 If any amplitude of is less than k times of the device rated current, 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 rated current of the device (k is a proportional coefficient between 1.1 and 1.3), there is no need to adjust cmd Ia0 And reactive current command information cmd Ir0 Processing, directly cmd Ia0 As cmd Ia 、Change cmd Ir0 As cmd Ir .

[0129] ④ If the amplitude of the synthesized total current instruction information is greater than k times the rated current of the device, and cmd Ia0 The amplitude is less than k times of the rated current, cmd Ir0 Greater than k times the rated current: only for cmd Ir0 Make corrections and get the corrected cmd Ir :cmd Ir The absolute value is the square root of the difference between the two parameters. The first parameter is the square of k times the rated current of the device, and the second parameter is cmd Ia0 square of cmd Ir The sign of 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 rated current of the device, cmd Ia0 The amplitude is greater than k times the rated current, cmd Ir0 If the amplitude is less than k times of the rated current, execute the correction process in ①.

[0131] ⑥ If the amplitude of the synthesized total current command information is greater than k times the rated current of the device, cmd Ia0 Amplitude, cmd Ir0 If the amplitudes of are all less than k times of the rated current, execute the correction process in ④.

[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 Clarke transform and Park transform are used in sequence, and then filtered by a low-pass filter (cut-off frequency is greater than 10Hz and less than 50Hz) to obtain the active current component I of the converter output current in the autonomous (i.e. off-grid) state of the distribution network. oa_离网 and the reactive component of current I or_离网 .

[0133] 6)cmd Ia Subtract I oa_离网 , perform PI (proportional plus integral) operation on the difference to obtain the direct axis signal u of the modulation wave instruction d1 .

[0134] 7)cmd Ir Subtract I or_离网 , perform PI (proportional plus integral) operation on the difference to obtain the quadrature axis signal u of the modulation wave instruction q1 .

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

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

[0137] In addition, in S104, the step of determining whether a fault occurs in the distribution network includes:

[0138] If the real-time information of the phase voltage amplitude of the converter port V 端口 < the preset first voltage threshold, it is considered that the distribution network has failed; if the real-time obtained converter port phase voltage amplitude information V 端口 > the preset second voltage threshold, it is considered that the distribution network has not failed; 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 value θ is calculated SUM , if the angle sum θ SUMIf it is not within the preset sum threshold range, it is considered that the distribution network has failed, otherwise it is considered that the distribution network has not failed; wherein, the first voltage threshold is less than the second voltage threshold.

[0139] In S104, the angle sum value θ is calculated SUM The steps include:

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

[0141] In a specific implementation process, the step of determining whether a fault occurs in the distribution network in S104 can be paraphrased as follows:

[0142] According to the real-time acquired A phase voltage phase signal θ AU , Real-time acquired port phase voltage amplitude information V 端口 , perform island detection, and when certain conditions are met, it is considered that a fault has occurred. At this time, the distribution network switches to island autonomy, otherwise the grid connection control operation shown in step S106 is executed.

[0143] The steps of determining whether a fault occurs in the distribution network in S104 can also be described as 1)-3):

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

[0145] 2) When the port voltage amplitude V 端口 If it is greater than 90% of its rated value, the distribution network is considered to have no fault.

[0146] 3) When the port voltage amplitude V 端口 When the angle is 80%-90% of the rated value, calculate the angle sum value θ SUM , and then determine whether a fault occurs.

[0147] ① Based on the existing transmission power, a certain reactive power Q is injected into the distribution network using the 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 is the current active power command value, Q ref is the current reactive power command value, A1 is the injection proportional coefficient, which can be 0.1.

[0150] ②Injected reactive power Q ref After that, the phase difference of the phase-locked loop outputs of two adjacent control cycles is calculated (the first phase-locked loop that meets this condition is defined as i), and the above difference values ​​are added up for a specified number of times to obtain the angle sum value θ SUM , where the number of consecutive designations is the controller's control frequency f divided by 50:

[0151]

[0152] Among them, θ AU,i The phase 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 i value is 1.

[0153] If the θ SUM If it is not within the preset sum threshold range, it is considered that the distribution network has failed; if it is within the preset sum threshold range, it is considered that the distribution network has not failed. This detection process is a rolling test process, that is, continuous detection of V 端口 When the value is between 80% and 90% of the rated value, Formula 13 and Formula 14 are executed.

[0154] Specifically, if θ SUM When it is less than 6.157rad or greater than 6.409rad, it is considered that a fault has occurred.

[0155] In short, when the terminal voltage amplitude V 端口 Less than 80% of the rated value or θ SUM If the value is not within the preset threshold range, it is considered that the distribution network has failed; otherwise, it is considered that the distribution network has not failed.

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

[0157] Specifically, S106 includes:

[0158] S1062: According to the active power P of the converter in the current operating state ref and reactive power Q ref Determine the converter active current command information 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 The current three-phase output current signal ioa 、i ob 、i oc After transformation and filtering, the active current component I of the converter output current in the grid-connected state is obtained. 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 in the grid-connected state oa_并网 and the reactive component of current I or_并网 Obtain the three-phase modulated wave signals xa', xb', xc' in the stationary coordinate system;

[0161] S1068: Perform pulse width modulation or space vector pulse width modulation on the three-phase modulated wave signals xa', xb', and xc' to obtain a switch control signal Y', 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) The current converter active power instruction P ref Divide by the amplitude information of the phase voltage at the converter port V 端口 , multiply the above result by 2 and divide by 3 to get the converter active current command information cmd Ia ′.

[0164] 2) The current converter reactive power instruction Q ref Divide by the amplitude information of the phase voltage at the converter port V 端口 , multiply the above result by 2 and divide by 3 to get the converter reactive current command information cmd Ir ′.

[0165] 3) The phase signal θ of the A phase voltage obtained according to the real-time phase-locked loop AU , for the three-phase output current signal i oa 、i ob 、i oc Clarke transform and Park transform are used in sequence, and then filtered through a low-pass filter (cut-off frequency is greater than 10Hz and less than 50Hz) to obtain the active current component I of the converter output current in the grid-connected state. oa_并网 and the reactive component of current I or_并网 .

[0166] 4)cmd Ia ' minus I oa_并网 , perform PI (proportional plus integral) operation on the difference to obtain the direct axis signal u of the modulation wave instructiond2 .

[0167] 5)cmd Ia ' minus I or_并网 , perform PI (proportional plus integral) operation on the difference to obtain the quadrature axis signal u of the modulation wave instruction q2 .

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

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

[0170] In addition, in S106, the step of determining whether the power distribution network has resumed power supply includes:

[0171] According to the active current component I of the converter output current under different continuous operating conditions oa , reactive component of current I or Determine a first angle value. If the first angle value is greater than a preset first angle threshold, start accumulating the count 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 the preset control threshold, it is considered that the distribution network has restored 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 S1028.

[0173] Specifically, the active current component I of the converter output current is continuously collected. oa , reactive component of current I or Take the quotient and perform an inverse tangent operation on the quotient. If the angle is greater than 0.5 radians, start counting and obtain the count value N. If the angle is less than 0.45, the count value is reset to zero. When the count value N exceeds the control period / 500, it is considered that the distribution network has restored power supply, otherwise it is considered that the distribution network has not restored 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 step of determining whether the power distribution network has restored power supply further includes:

[0177] Whether the distribution network has restored power supply is confirmed based on the switch status at the common bus of the distribution network received by the converter.

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

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

[0180] 1. The existing technology relies on synchronous satellite assistance to achieve fixed frequency control, but it increases the cost. In S1042, this application uses the phase voltage amplitude information V of the converter port to achieve fixed frequency control. 端口 , the active voltage component U of the line impedance voltage a and voltage reactive component U r The preliminary phase command signal θ for global synchronization is determined s , it can also achieve synchronization and reduce costs.

[0181] 2. During the process of grid connection to autonomy or autonomous secondary grid connection, current shock problems may occur. The present application can not only realize steady-state fixed-frequency control without relying on synchronous satellites (see S1042), but also can switch smoothly and flexibly (see S1044, S1046, S106), which is beneficial to reduce the current stress during the switching transient process.

[0182] 3. The fixed-frequency networking control in the present invention can not only get rid of the dependence on satellite timing signals (see S1042), but also realize flexible control of the output current phase of the converter during the transition from grid connection to autonomy (see S1044, S1046, S106), which is conducive to reducing the cost of equipment and improving the operational reliability of the equipment.

[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 dependence on communication methods such as satellite timing, thereby reducing costs.

[0184] 5. During the transient transition from grid connection to autonomous operation, frequency gradient control is used to ensure that the output current phase of the converter does not change suddenly and the frequency fluctuation is small under transient conditions (see S1044, S1046, and S106). This is beneficial to reducing the transient stress of the current during the switching transient period.

[0185] 6. Not only can the distribution network operate in an autonomous operating state at a constant frequency (see S1044, S1046, S106), but it can also avoid dependence on timing tools (see S1042), and can also achieve flexible switching between grid connection / autonomy (i.e., off-grid), autonomy and grid connection.

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

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

[0188] 9. The correction process of S10462 calculates the active current command information by PI operation of the voltage amplitude, and the reactive component U of the converter port voltage or_变流器 By obtaining the reactive current command information, the reactive power output of the converter can be used to achieve on-site reactive power compensation. 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, thereby taking into account the converter's active output, reactive power compensation (meeting the target power factor) and the reliability of the long-term operation of the equipment.

[0189] 10. In S1046, the converter port voltage command U is modified by the remote global controller and the converter self-regulation mode. set , which not only ensures the distributed characteristics of voltage in the distribution network, but also realizes accurate voltage regulation, and is also conducive to ensuring the control of power flow in autonomous microgrids.

[0190] 11. In S106, the count value N is calculated based on the reactive component of the converter output current divided by the active component, which can more quickly and accurately determine whether the power grid has recovered.

[0191] 12. Under the premise of improving the power-angle stability and frequency stability problems during autonomous operation of a high-proportion distribution station area, this embodiment, on the one hand, 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 timing, which is conducive to reducing costs; on the other hand, during the transient transition from grid connection to autonomy, frequency gradient control is adopted to ensure that the output current phase of the converter will not change suddenly and the frequency fluctuation is small under transient conditions, which is conducive to reducing the transient stress of the current during the switching transient period.

[0192] 13. This embodiment not only enables the distribution network to operate in an autonomous operating state at a constant frequency, but also avoids dependence on timing tools, and can also achieve flexible switching between grid-connected and autonomous, and autonomous and grid-connected.

[0193] Example 3

[0194] This embodiment provides an active distribution network multi-resource coordinated 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 according to the initial signal of the converter. a and voltage reactive component U r .

[0196] The second control module is used to control the active voltage component U of 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 adjusted synchronously and dynamically to realize the control of the converter output current in the off-grid state.

[0197] The third control module is used to control the output current of the converter in the grid-connected state based on the current operating state if the power distribution network resumes power supply.

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

[0199] Example 4

[0200] Figure 4 FIG. 1 is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention. Figure 4 As shown, the above-mentioned electronic device may include at least one processor; and at least one memory communicatively connected to the above-mentioned processor, wherein: the memory stores program instructions that can be executed by the processor, and the above-mentioned processor calls the above-mentioned program instructions to execute the above-mentioned active distribution network multi-resource collaborative and off-grid control method of the present invention.

[0201] Figure 4A block diagram is shown of an exemplary electronic device suitable for implementing exemplary embodiments of the present invention. Figure 4 The electronic device shown is only an example and should not limit the functions and scope of use of the embodiments of the present invention.

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

[0203] Communication bus 440 represents one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processor, or a local bus using any of a variety of bus architectures. Examples of these architectures include, but are not limited to, the Industry Standard Architecture (ISA) bus, the Micro Channel Architecture (MAC) bus, the Enhanced ISA bus, the Video Electronics Standards Association (VESA) local bus, and the Peripheral Component Interconnect (PCI) bus.

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

[0205] Memory 430 may include computer-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 may 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 generally perform the functions and / or methods described in the embodiments of the present invention.

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

[0208] Example 5

[0209] An embodiment of the present invention provides a non-transitory computer-readable storage medium, which stores computer instructions, and the computer instructions enable the computer to execute the active distribution network multi-resource coordination and off-grid control method of the above embodiment of the present invention.

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

[0211] A computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, which carries computer-readable program code. Such a propagated data signal may take a variety of forms, including, but not limited to, electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium that can transmit, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0212] Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0213] The computer program code for performing the operation of the 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, C++, and conventional procedural programming languages ​​such as "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as an independent software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer through any type of network, including a local area network (Local Area Network; hereinafter referred to as: LAN) or a wide area network (Wide Area Network; hereinafter referred to as: WAN), or can be connected to an external computer (for example, using an Internet service provider to connect through the Internet).

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

[0215] In the description of the embodiments of the present invention, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present invention. In the embodiments of the present invention, the schematic representations 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 any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in the embodiments of the present invention and the features of different embodiments or examples, unless they are mutually inconsistent.

[0216] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of the embodiments of the present invention, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0217] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred implementation of the embodiments of the invention includes alternative implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the invention pertain.

[0218] The word "if," as used herein, may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to the determination" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)," depending on the context.

[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 (Personal Computer; hereinafter referred to as: PC), personal digital assistants (Personal Digital Assistant; hereinafter referred to as: PDA), wireless handheld devices, tablet computers (Tablet Computer), mobile phones, MP3 players, MP4 players, etc.

[0220] In the several embodiments provided in the embodiments of the present invention, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. 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. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection of the devices or units through some interfaces, which may be electrical, mechanical or other forms.

[0221] In addition, the functional units in various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or hardware plus software functional units.

[0222] The above-mentioned integrated unit implemented in the form of a software functional unit can be stored in a computer-readable storage medium. The above-mentioned software functional unit is stored in a storage medium and includes a number of instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) or a processor to perform some of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, an optical disk, and other media that can store program code.

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

Claims

1. A method for controlling multi-resource coordination and on-grid disconnection in an active distribution network, characterized in that: The method comprises: S102: Determine the active voltage component U of the line impedance voltage according to 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 achieve 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 is controlled in the grid-connected state based on the current operating state.

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 u of the converter port voltage under different operating states based on the initial signal of the converter obtained in real time d , port voltage quadrature axis component u q And the converter output current direct axis component i 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 , output current direct axis component difference Δi d , output current quadrature axis component difference Δi q ; 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 , output current direct axis component difference Δi d , output current quadrature axis component difference Δi q Determine the average resistive component of the line impedance and average perceptual component S1028: Based on the real-time acquired phase-locked loop A phase voltage phase signal θ AU Determine the active component I of the converter output current oa and the 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 , the average resistive component of the line impedance and average perceptual component Split the line impedance voltage into the active voltage component U a and voltage reactive component U r .

3. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 2, characterized in that: S104 includes: S1042: Calculate the active voltage component U of the line impedance voltage according to the voltage a and voltage reactive component U r Confirm the current phase-locked loop A phase voltage phase signal θ AU The preliminary phase command signal θ obtained in advance and synchronized with the global s The first phase difference between S1044: Based on the first phase difference The phase-A voltage phase signal θ obtained in real time AU Perform dynamic adjustment to obtain real-time phase command signal θ srt ; S1046: In the off-grid state, according to the real-time phase command signal θ srt Controls the output current of the converter.

4. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 3, characterized in that: S1042 includes: S10422: Real-time converter port voltage direct axis component u obtained according to S1022 d and the quadrature axis component u of the port voltage q Determine the phase voltage amplitude information V of 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 retrospective time interval Δt and the phase offset angle Get the preliminary phase command signal θ for global synchronization s ; S10428: The preliminary phase command signal θ of global synchronization s and the phase-locked loop A phase voltage phase signal θ at the current moment AU The first phase difference is obtained by subtracting 5. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 3, characterized in that: S1044 includes: S10442: If the first phase difference Based on the first gradient frequency f a , the preset recall 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 operation; S10444: If the first phase difference Based on the second gradient frequency f b , the preset recall 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 operation.

6. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 3, characterized in that: S1046 includes: S10462: Based on the converter three-phase port voltage signal u in the converter initial signal obtained in real time a 、u b 、u c Determine the converter active current command information 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 Perform conversion and filtering to obtain the active current component I of the converter output current in the off-grid state. oa_离网 and the reactive component of current I or_离网 ; 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 the off-grid state oa_离网 and the reactive component of current I or_离网 Obtain the three-phase modulated wave signals xa, xb, and xc in the stationary coordinate system; S10468: Perform pulse width modulation or space vector pulse width modulation on the three-phase modulated wave signals xa, xb, and xc to obtain a switch control signal Y, and control the output current of the converter based on the control signal Y.

7. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 1, characterized in that: In S104, the step of determining whether a fault occurs in the distribution network includes: If the real-time information of the phase voltage amplitude of the converter port V 端口 < the preset first voltage threshold, it is considered that the distribution network has failed; If the real-time information of the phase voltage amplitude of the converter port V 端口 >The preset second voltage threshold is considered to be no fault in the distribution network; If the phase voltage amplitude information V 端口 Between the preset first voltage threshold and the preset second voltage threshold, the angle sum value θ is calculated SUM , if the angle sum θ SUM If it is not within the preset sum threshold range, it is considered that the distribution network has failed, otherwise it is considered that the distribution network has not failed; wherein, the first voltage threshold is less than the second voltage threshold.

8. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 7, characterized in that: In S104, the angle sum value θ is calculated SUM The steps include: The preset amount of reactive power is injected into the distribution network, and the port voltage amplitude V after the reactive power is injected is calculated. 端口 and A phase voltage phase signal θ AU Determine the angle sum θ SUM .

9. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 2, characterized in that: In S106, the step of determining whether the power distribution network has resumed power supply includes: According to the active current component I of the converter output current under different continuous operating conditions oa , reactive component of current I or Determine a first angle value, and if the first angle value is greater than a preset first angle threshold, start accumulating the count value 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 is greater than the preset control threshold, it is considered that the distribution network has restored power supply.

10. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 9, characterized in that: In S106, the step of determining whether the power distribution network has restored power supply further includes: Whether the distribution network has restored power supply is confirmed based on the switch status at the common bus of the distribution network received by the converter.

11. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 1, characterized in that: S106 includes: S1062: According to the active power P of the converter in the current operating state ref and reactive power Q ref Determine the converter active current command information 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 After transformation and filtering, the active current component I of the converter output current in the grid-connected state is obtained. oa_并网 and the reactive component of current I or_并网 ; 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 in the grid-connected state oa_并网 and the reactive component of current I or_并网 Obtain the three-phase modulated wave signals xa', xb', 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 a switch control signal Y', and control the output current of the converter based on the control signal Y'.

12. 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, executing S106.

13. 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 restored power supply, executing S104.

14. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 6, characterized in that: S10462 includes: S104622: According to the phase signal θ of the phase-locked loop A voltage AU The voltage signal u of the three-phase port of the converter a 、u b 、u c Clarke transform, Park transform and filtering are used to obtain the voltage reactive component U of the converter port voltage. or_变流器 ; S104624: According to the pre-acquired converter port voltage amplitude instruction U set and the converter port voltage amplitude V 端口 Determine the initial converter active current command information cmd Ia0 ; S104626: Reactive voltage component U of the converter port voltage or_变流器 After taking the negative, perform proportional plus integral operation 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 Correct the converter active current command information cmd Ia And reactive current command information cmd Ir .

15. The active distribution network multi-resource coordinated on-grid and off-grid control method according to claim 14, characterized in that: In S104624, obtain the port voltage amplitude instruction U of the converter 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 at the previous moment set0 , Real-time acquired converter port phase voltage amplitude information V 端口 , the average resistive component of the line impedance Determine the converter's port voltage amplitude command U set ; or, Based on the current off-grid area topology and line impedance, the port voltage amplitude command U of the converter in the distribution network is obtained through power flow calculation. set .

16. An active distribution network multi-resource coordinated on-grid and off-grid control device, characterized in that: The device comprises: The first control module is used to determine the active voltage component U of the line impedance voltage according to the initial signal of the converter. a and voltage reactive component U r ; The second control module is used to control the active voltage component U of the line impedance voltage if a fault occurs in the distribution network. a and voltage reactive component U r Synchronously and dynamically adjust the phase command of the converter output current to achieve control of the converter output current in the off-grid state; The third control module is used to control the output current of the converter in the grid-connected state based on the current operating state if the power distribution network resumes power supply.

17. An electronic device, characterized in that: include: at least one processor; as well as at least one memory in communication with the processor, wherein: The memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to execute the active distribution network multi-resource coordinated and off-grid control method according to any one of claims 1 to 15.

18. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions, and the computer instructions enable the computer to execute the active power distribution network multi-resource coordinated on-grid and off-grid control method according to any one of claims 1 to 15.

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