A signal injection-based network-forming converter control method and device

Abstract

The present application relates to the technical field of flexible direct current power transmission, and specifically provides a network-constructing converter control method and device based on signal injection, comprising: determining a working mode of a network-constructing converter based on the operating condition of the network-constructing converter and a new energy system; determining a network-side current derivation value of the network-constructing converter based on the working mode; generating a driving pulse for driving the network-constructing converter based on the network-side current derivation value, and controlling the network-constructing converter by using the driving pulse; the technical scheme provided by the present application can reduce the risk of system instability, effectively suppress the power angle deviation of weak grid voltage under fault and sudden change condition, ensure the power angle stability of the network-constructing converter of the weak grid, more effectively improve the network-constructing performance of the network-constructing converter, increase the flexibility of the distributed new energy end, and realize the power stability and stable operating condition operation of the weak grid with the network-constructing and high new energy proportion.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flexible direct current power transmission, in particular to a network-constructing converter control method and device based on signal injection. BACKGROUND

[0002] With the accelerated construction of new power systems, the proportion of new energy is increasing, and the system inertia support is insufficient, the short-circuit ratio is too low, the wideband oscillation is weak, and the anti-disturbance ability is weak, which has become a prominent problem restricting the efficient use of new energy. At the same time, the external power receiving proportion of the receiving end power grid is high, and the load center voltage stability problem is prominent, and the power system safety and stability operation guarantee is under great pressure. The network-constructing technology has strong weak grid adaptability, can effectively improve the inertia damping characteristics of the power grid, and actively provides voltage and frequency support for the system, and has broad application prospects in new power systems.

[0003] During power grid failure or power grid state mutation, the fault current variation of new energy grid connection is extremely high. Since new energy is connected to the grid based on power electronic converters, the overcurrent resistance is poor, and during abnormal operation, new energy is prone to be disconnected from the grid, and even the grid-connected equipment is damaged, so it is difficult to realize the ride-through control.

[0004] The current fault ride-through strategy for network-constructing new energy is to add a current control link in the inner loop of network-constructing control, and to realize fault ride-through through current limiting or constant current control. However, this fault ride-through method requires modification of the network-constructing control link, thereby introducing control delay and reducing the stability of the control system. In addition, the forced current limiting control strategy reduces the power angle stability of the network-constructing new energy, and the constant current control strategy is essentially a grid-following control strategy, which reduces the ability of the network-constructing new energy to support power grid operation during faults.

[0005] For example, patent CN120280889A designs a network-constructing new energy fault ride-through method and system for realizing amplitude and phase stability, which only needs to adjust the power reference value of the control link to realize the fault ride-through of the network-constructing new energy. Compared with the traditional current-based fault ride-through control, the control response speed and stability of the network-constructing new energy are improved. However, this design only considers the power reference value factor and does not consider the change and search of the optimal operating point after the working condition changes under weak grid conditions, which affects the utilization rate of direct current voltage.

[0006] Patent CN120281096A provides a network type energy storage system reconstruction method and system based on dynamic impedance matching, which adopts high-frequency disturbance signal injection decoupling method to obtain real-time impedance and real-time reactance of the associated power grid, and combines the closed-loop control of impedance outer loop and voltage inner loop to realize transient impact suppression and oscillation suppression, effectively avoiding the limitation of separate triggering and improving the grid voltage control effect. However, the direct high-frequency disturbance signal injection used in this design will increase the instability risk of weak power grid, and the real-time reactance calculation will increase the calculation cost and hardware cost.

[0007] Patent CN113394825B introduces the concept of virtual power and proposes a quadrature power synchronous control strategy. The proposed method can suppress the power angle deviation between the voltage source converter and the power grid during fault, prevent the VSC from losing the static operating point, avoid synchronization instability, and improve the synchronization stability of grid-connected inverters in extremely weak power grid conditions. However, this design can only alleviate part of the transient problem of weak power grid and cannot be applied to more extensive unconventional conditions and fault problems. SUMMARY

[0008] To overcome the above-mentioned defects, the present application provides a signal injection-based network type converter control method and device.

[0009] In a first aspect, a signal injection-based network type converter control method is provided, which includes:

[0010] Determining the working mode of the network type converter based on the operating conditions of the network type converter and the new energy system;

[0011] Determining the network side current derivation value of the network type converter based on the working mode;

[0012] Generating a driving pulse for driving the network type converter based on the network side current derivation value, and controlling the network type converter using the driving pulse;

[0013] When the working mode of the network type converter is the dynamic working mode, determining the network side current derivation value of the network type converter based on the working mode includes:

[0014] Determining the virtual power reference value of the network type converter based on the network side current and the network side voltage of the network type converter;

[0015] Determining the target power angle of the network type converter based on the virtual power of the network type converter;

[0016] The difference between the initial power angle and the target power angle of the grid-connected converter is subjected to a PI controller to obtain an initial derived value of the grid-side three-phase current of the grid-connected converter, and the initial derived value of the grid-side three-phase current is subjected to dq conversion to obtain a dq-axis component of the initial derived value of the grid-side current of the grid-connected converter;

[0017] Signal injection is performed on the dq-axis component of the initial derived value of the grid-side current of the grid-connected converter respectively to obtain a derived value of the grid-side current of the grid-connected converter;

[0018] When the working mode of the grid-connected converter is a static working mode, the determination of the derived value of the grid-side current of the grid-connected converter based on the working mode comprises:

[0019] The active boundary trajectory and the reactive boundary trajectory of the grid-connected converter are determined based on the grid-side current and the grid-side voltage of the grid-connected converter;

[0020] Feasible region calculation is performed based on the active boundary trajectory and the reactive boundary trajectory of the grid-connected converter to obtain a reactive power reference value and a grid-side voltage reference value of the grid-connected converter;

[0021] The difference between the reactive power reference value of the grid-connected converter and an actual value of the reactive power of the grid-connected converter and the difference between the grid-side voltage reference value of the grid-connected converter and an actual value of the grid-side voltage of the grid-connected converter are subjected to PI controllers respectively to obtain the derived value of the grid-side current of the grid-connected converter.

[0022] Preferably, the determination of the working mode of the grid-connected converter based on the operating conditions of the grid-connected converter and the new energy system comprises:

[0023] When the grid-connected converter fails and the operating state has multiple conditions, the working mode of the grid-connected converter is a dynamic working mode;

[0024] When the grid-connected converter fails and operates in a single condition, the working mode of the grid-connected converter is a static working mode.

[0025] Preferably, the virtual power reference value of the grid-connected converter is as follows:

[0026]

[0027] In the above formula, P v-ref is a virtual power reference value of the grid-connected converter, u g-α is a grid-side voltage α axis of the grid-connected converter, u g-β is a grid-side voltage β axis of the grid-connected converter, ig-v-α Virtual quadrature output current for grid-forming converter α axis quantity, i g-v-β Virtual quadrature output current for grid-forming converter β axis quantity.

[0028] Further, the target power angle of the grid-forming converter satisfies:

[0029]

[0030] In the above formula, E is the new energy collection end voltage corresponding to the initial operation condition of the grid-forming converter, E sag New energy collection end voltage corresponding to the target working condition when the grid-forming converter is in operation state transition, delta f Target power angle of the grid-forming converter, C Synchronization coefficient, lambda Disturbance quantity of angle, X g Grid-side impedance of the grid-forming converter, P ref Power reference value of the grid-forming converter, U g Grid-side voltage of the grid-forming converter.

[0031] Further, the initial power angle of the grid-forming converter satisfies:

[0032]

[0033] In the above formula, E is the new energy collection end voltage corresponding to the initial operation condition of the grid-forming converter, delta Initial power angle of the grid-forming converter.

[0034] Further, the grid-side current derivation value of the grid-forming converter is as follows:

[0035]

[0036] In the above formula, E is the new energy collection end voltage corresponding to the initial operation condition of the grid-forming converter, i d++ d-axis component of the grid-side current derivation value of the grid-forming converter, i d+ d-axis component of the initial derivation value of the grid-side current of the grid-forming converter, i q++ q-axis component of the grid-side current derivation value of the grid-forming converter, i q+ q-axis component of the initial derivation value of the grid-side current of the grid-forming converter, A Amplitude of the injection signal, omega ha frequency of the injected signal, t a time of the injected signal.

[0037] Preferably, the mathematical model corresponding to the active boundary trajectory of the grid-forming converter is as follows:

[0038]

[0039] In the above formula, ( x u , y u ) are the horizontal and vertical coordinates of the active / reactive boundary trajectory end point of the grid-forming converter, U g is the grid-side voltage of the grid-forming converter, X g is the grid-side impedance of the grid-forming converter, R g is the grid-side reactance of the grid-forming converter, and P is the grid-side active power of the grid-forming converter.

[0040] Further, the mathematical model corresponding to the reactive boundary trajectory of the grid-forming converter is as follows:

[0041]

[0042] In the above formula, ( x u , y u ) are the horizontal and vertical coordinates of the active / reactive boundary trajectory end point of the grid-forming converter, U g is the grid-side voltage of the grid-forming converter, X g is the grid-side impedance of the grid-forming converter, R g is the grid-side reactance of the grid-forming converter, and Q is the grid-side reactive power of the grid-forming converter.

[0043] Preferably, the feasible region calculation based on the active boundary trajectory and the reactive boundary trajectory of the grid-forming converter to obtain the reactive power reference value and the grid-side voltage reference value of the grid-forming converter comprises:

[0044] obtaining the intersection point of the active boundary trajectory and the reactive boundary trajectory of the grid-forming converter;

[0045] selecting the intersection point corresponding to the power angle less than the preset value, obtaining the reactive power and the voltage corresponding to the intersection point, and taking the reactive power and the voltage as the reactive power reference value and the grid-side voltage reference value of the grid-forming converter.

[0046] Preferably, the generating of the driving grid-forming converter driving pulse based on the grid-side current derivation value comprises:

[0047] differences between the network-side current derived values of the network-forming converter and actual values of the network-side current are controlled by a PI controller to obtain network-side voltage reference values of the network-forming converter;

[0048] a driving pulse for driving the network-forming converter is generated using the network-side voltage reference values of the network-forming converter, and the network-forming converter is controlled using the driving pulse.

[0049] In a second aspect, a signal injection-based network-forming converter control device is provided, and the signal injection-based network-forming converter control device comprises:

[0050] A first determination module is configured to determine a working mode of a network-forming converter based on an operating condition of the network-forming converter and a new energy system.

[0051] A second determination module is configured to determine a network-side current derived value of the network-forming converter based on the working mode.

[0052] A control module is configured to generate a driving pulse for driving the network-forming converter based on the network-side current derived value, and control the network-forming converter using the driving pulse.

[0053] When the working mode of the network-forming converter is a dynamic working mode, the second determination module is specifically configured to:

[0054] A virtual power reference value of the network-forming converter is determined based on a network-side current and a network-side voltage of the network-forming converter.

[0055] A target power angle of the network-forming converter is determined based on the virtual power of the network-forming converter.

[0056] A difference between an initial power angle of the network-forming converter and the target power angle is controlled by a PI controller to obtain an initial derived value of a network-side three-phase current of the network-forming converter, and a dq-axis component of the initial derived value of the network-side current of the network-forming converter is obtained by dq conversion of the initial derived value of the network-side three-phase current of the network-forming converter.

[0057] Signal injection is performed on the dq-axis component of the initial derived value of the network-side current of the network-forming converter respectively to obtain a network-side current derived value of the network-forming converter.

[0058] When the working mode of the network-forming converter is a static working mode, the second determination module is specifically configured to:

[0059] An active boundary trajectory and a reactive boundary trajectory of the network-forming converter are determined based on a network-side current and a network-side voltage of the network-forming converter.

[0060] The feasible region is calculated based on the active boundary trajectory and the reactive boundary trajectory of the network-forming converter, to obtain a reactive power reference value and a grid-side voltage reference value of the network-forming converter;

[0061] The difference between the reactive power reference value of the network-forming converter and an actual value of the reactive power of the network-forming converter and the difference between the grid-side voltage reference value of the network-forming converter and an actual value of the grid-side voltage of the network-forming converter are respectively subjected to PI controllers to obtain a grid-side current derivation value of the network-forming converter.

[0062] Preferably, the first determination module is specifically configured to:

[0063] When the network-forming converter fails and the operating state has multiple operating conditions, the working mode of the network-forming converter is a dynamic working mode.

[0064] When the network-forming converter fails and operates in a single operating condition, the working mode of the network-forming converter is a static working mode.

[0065] Preferably, the virtual power reference value of the network-forming converter is as follows:

[0066]

[0067] In the above formula, P v-ref is a virtual power reference value of the network-forming converter, u g-α is a grid-side voltage α axis of the network-forming converter, u g-β is a grid-side voltage β axis of the network-forming converter, i g-v-α is a virtual quadrature output current α axis of the network-forming converter, i g-v-β is a virtual quadrature output current β axis of the network-forming converter.

[0068] Further, the target power angle of the network-forming converter satisfies:

[0069]

[0070] In the above formula, E sag is a new energy collection end voltage corresponding to a state transition of the network-forming converter to a target operating condition, delta f is a target power angle of the network-forming converter, C is a synchronization coefficient, lambda is a disturbance amount of an angle, Xg is a grid-side impedance of the grid-forming converter, P ref is a power reference value of the grid-forming converter, U g is a grid-side voltage of the grid-forming converter.

[0071] Further, an initial power angle of the grid-forming converter satisfies:

[0072]

[0073] In the above formula, E is a new energy collection end voltage corresponding to an initial operation condition of the grid-forming converter, delta is an initial power angle of the grid-forming converter.

[0074] Further, a grid-side current derivation value of the grid-forming converter is as follows:

[0075]

[0076] In the above formula, i d++ is a d-axis component of the grid-side current derivation value of the grid-forming converter, i d+ is a d-axis component of an initial grid-side current derivation value of the grid-forming converter, i q++ is a q-axis component of the grid-side current derivation value of the grid-forming converter, i q+ is a q-axis component of the initial grid-side current derivation value of the grid-forming converter, A is an amplitude of the injected signal, omega h is a frequency of the injected signal, t is a time of the injected signal.

[0077] Preferably, a mathematical model corresponding to the active boundary trajectory of the grid-forming converter is as follows:

[0078]

[0079] In the above formula, ( x u , y u ) is a horizontal and vertical coordinate of an active / reactive boundary trajectory end point of the grid-forming converter, U g is a grid-side voltage of the grid-forming converter, X g is a grid-side impedance of the grid-forming converter, R g is a grid-side reactance of the grid-forming converter, and P is a grid-side active power of the grid-forming converter.

[0080] Further, the mathematical model corresponding to the reactive boundary trajectory of the grid-forming converter is as follows:

[0081]

[0082] In the above formula, ( x u , y u ) is the horizontal and vertical coordinates of the active / reactive boundary trajectory end point of the grid-forming converter, U g is the grid-side voltage of the grid-forming converter, X g is the grid-side impedance of the grid-forming converter, R g is the grid-side reactance of the grid-forming converter, and Q is the grid-side reactive power of the grid-forming converter.

[0083] Preferably, the feasible region calculation based on the active boundary trajectory and the reactive boundary trajectory of the grid-forming converter obtains a reactive power reference value and a grid-side voltage reference value of the grid-forming converter, including:

[0084] obtaining the intersection point of the active boundary trajectory and the reactive boundary trajectory of the grid-forming converter;

[0085] selecting the intersection point corresponding to a power angle less than a preset value, obtaining the reactive power and voltage corresponding to the intersection point, and taking the reactive power and voltage as the reactive power reference value and the grid-side voltage reference value of the grid-forming converter.

[0086] Preferably, the generation of the driving pulse for driving the grid-forming converter based on the grid-side current derivation value includes:

[0087] deriving the grid-side voltage reference value of the grid-forming converter through PI control of the difference between the grid-side current derivation value and the actual value of the grid-side current of the grid-forming converter;

[0088] generating the driving pulse for driving the grid-forming converter by using the grid-side voltage reference value of the grid-forming converter, and controlling the grid-forming converter by using the driving pulse.

[0089] In a third aspect, a computer device is provided, including: one or more processors;

[0090] the processor is configured to execute one or more programs;

[0091] when the one or more programs are executed by the one or more processors, the grid-forming converter control method based on signal injection is implemented.

[0092] In a fourth aspect, a computer readable storage device is provided, and a computer program is stored on the computer readable storage device, and the computer program is executed to implement the signal injection-based grid-forming converter control method.

[0093] The one or more technical solutions of the present application have at least one or more of the following beneficial effects:

[0094] The present application relates to the technical field of flexible direct current power transmission, and specifically provides a signal injection-based grid-forming converter control method and device, which comprises the following steps: determining a working mode of a grid-forming converter based on an operating condition of the grid-forming converter and a new energy system; determining a grid-side current derivation value of the grid-forming converter based on the working mode; generating a driving pulse for driving the grid-forming converter based on the grid-side current derivation value, and controlling the grid-forming converter by using the driving pulse; and the technical solution provided by the present application can reduce the risk of system instability, effectively suppress the power angle deviation of a weak grid voltage under fault and sudden change conditions, ensure the power angle stability of the grid-forming converter of the weak grid, and more effectively improve the grid-forming performance of the grid-forming converter, increase the flexibility of the distributed new energy end, and realize the power stability and stable operating condition operation of the weak grid with a high proportion of grid-forming and new energy. BRIEF DESCRIPTION OF DRAWINGS

[0095] Figure 1 FIG. 1 is a main step flow diagram of the signal injection-based grid-forming converter control method according to an embodiment of the present application;

[0096] Figure 2 FIG. 2 is a principle diagram of the signal injection-based grid-forming converter control method when the working mode of the grid-forming converter is a dynamic working mode according to an embodiment of the present application;

[0097] Figure 3 FIG. 3 is a principle diagram of the signal injection-based grid-forming converter control method when the working mode of the grid-forming converter is a static working mode according to an embodiment of the present application;

[0098] Figure 4 FIG. 4 is a curve diagram of the active boundary trajectory and the reactive boundary trajectory of the grid-forming converter according to an embodiment of the present application. DETAILED DESCRIPTION

[0099] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0100] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0101] Embodiment 1

[0102] Reference is made to the accompanying Figure 1 , Figure 1 Figure 1 is a schematic diagram of main steps of a signal injection-based grid-forming converter control method according to an embodiment of the present application. As shown in Figure 1, the signal injection-based grid-forming converter control method according to the embodiment of the present application mainly includes the following steps: Figure 1

[0103] Step S101: determining a working mode of a grid-forming converter based on an operating condition of the grid-forming converter and a new energy system;

[0104] Step S102: determining a grid-side current derivation value of the grid-forming converter based on the working mode;

[0105] Step S103: generating a driving pulse for driving the grid-forming converter based on the grid-side current derivation value, and controlling the grid-forming converter by using the driving pulse;

[0106] As shown in Figure 1, when the working mode of the grid-forming converter is a dynamic working mode, the determination of the grid-side current derivation value of the grid-forming converter based on the working mode includes: Figure 2 determining a grid-side current of the grid-forming converter based on a grid-side voltage of the grid-forming converter and a grid-side voltage of the new energy system;

[0107] I g U g determining a virtual power reference value of the grid-forming converter based on the grid-side current of the grid-forming converter and the grid-side voltage of the grid-forming converter; P v

[0108] determining a target power angle of the grid-forming converter based on the virtual power of the grid-forming converter;

[0109] obtaining an initial derivation value of a grid-side three-phase current of the grid-forming converter by a PI controller based on a difference between an initial power angle of the grid-forming converter and the target power angle; i g * obtaining a dq-axis component of the initial derivation value of the grid-side three-phase current of the grid-forming converter by dq conversion based on the initial derivation value of the grid-side three-phase current of the grid-forming converter; ​​​​

[0110] Signal injection is performed on dq-axis components of the initial deduced value of the grid-side current of the grid-forming converter to obtain a deduced value of the grid-side current of the grid-forming converter;

[0111] As shown in Figure 3 when the working mode of the grid-forming converter is a static working mode, the determination of the deduced value of the grid-side current of the grid-forming converter based on the working mode comprises:

[0112] determination of active boundary trajectories and reactive boundary trajectories of the grid-forming converter based on the grid-side current and the grid-side voltage of the grid-forming converter;

[0113] feasible region calculation based on the active boundary trajectories and the reactive boundary trajectories of the grid-forming converter to obtain a reactive power reference value of the grid-forming converter Q ref and a grid-side voltage reference value U g-ref ;

[0114] the difference between the reactive power reference value of the grid-forming converter and an actual value of the reactive power of the grid-forming converter and the difference between the grid-side voltage reference value of the grid-forming converter and an actual value of the grid-side voltage of the grid-forming converter are respectively subjected to PI controllers to obtain the deduced value of the grid-side current of the grid-forming converter.

[0115] In this embodiment, the determination of the working mode of the grid-forming converter based on the operating conditions of the grid-forming converter and the new energy system comprises:

[0116] when the grid-forming converter fails and the operating state has multiple conditions, the working mode of the grid-forming converter is a dynamic working mode

[0117] when the grid-forming converter fails and operates in a single condition, the working mode of the grid-forming converter is a static working mode.

[0118] In this embodiment, the virtual power reference value of the grid-forming converter is as follows:

[0119]

[0120] In the above formula, P v-ref is the virtual power reference value of the grid-forming converter, u g-α is a grid-side voltage α axis quantity of the grid-forming converter, u g-β is a grid-side voltage β axis quantity of the grid-forming converter, i g-v-α is the virtual orthogonal output current of the grid-forming converterα axis quantity, i g-v-β a target power angle of the grid-forming converter β axis quantity.

[0121] In one embodiment, the target power angle of the grid-forming converter satisfies:

[0122]

[0123] In the above formula, E is a new energy collection end voltage corresponding to an initial operating condition of the grid-forming converter, E sag a new energy collection end voltage corresponding to a target operating condition of the grid-forming converter, delta f a target power angle of the grid-forming converter, C a synchronization coefficient, lambda a disturbance quantity of an angle, X g a grid-side impedance of the grid-forming converter, P ref a power reference value of the grid-forming converter, U g a grid-side voltage of the grid-forming converter.

[0124] In one embodiment, the initial power angle of the grid-forming converter satisfies:

[0125]

[0126] In the above formula, E is a new energy collection end voltage corresponding to an initial operating condition of the grid-forming converter, delta an initial power angle of the grid-forming converter.

[0127] In one embodiment, the grid-side current derivation value of the grid-forming converter is as follows:

[0128]

[0129] In the above formula, E is a new energy collection end voltage corresponding to an initial operating condition of the grid-forming converter, i d++ a d-axis component of the grid-side current derivation value of the grid-forming converter, i d+ a d-axis component of an initial grid-side current derivation value of the grid-forming converter, i q++ a q-axis component of the grid-side current derivation value of the grid-forming converter, i q+ a q-axis component of an initial grid-side current derivation value of the grid-forming converter, A a magnitude of the injected signal, omega h a frequency of the injected signal, tTime for injecting the signal.

[0130] In this embodiment, the mathematical model corresponding to the active boundary trajectory of the grid-forming converter is as follows:

[0131]

[0132] In the above formula, ( x u , y u ) are the horizontal and vertical coordinates of the active / reactive boundary trajectory end point of the grid-forming converter, U g is the grid-side voltage of the grid-forming converter, X g is the grid-side impedance of the grid-forming converter, R g is the grid-side reactance of the grid-forming converter, and P is the grid-side active power of the grid-forming converter.

[0133] In one embodiment, the mathematical model corresponding to the reactive boundary trajectory of the grid-forming converter is as follows:

[0134]

[0135] In the above formula, ( x u , y u ) are the horizontal and vertical coordinates of the active / reactive boundary trajectory end point of the grid-forming converter, U g is the grid-side voltage of the grid-forming converter, X g is the grid-side impedance of the grid-forming converter, R g is the grid-side reactance of the grid-forming converter, and Q is the grid-side reactive power of the grid-forming converter.

[0136] In this embodiment, the feasible region calculation based on the active boundary trajectory and the reactive boundary trajectory of the grid-forming converter obtains the reactive power reference value and the grid-side voltage reference value of the grid-forming converter, including:

[0137] obtaining the intersection point of the active boundary trajectory P-E and the reactive boundary trajectory Q-E of the grid-forming converter, for example, points b and c in Figure 4

[0138] selecting the intersection point corresponding to the power angle less than the preset value, obtaining the reactive power and voltage corresponding to the intersection point, and taking the reactive power and voltage as the reactive power reference value and the grid-side voltage reference value of the grid-forming converter;

[0139] wherein the power angle is as follows Figure 4 ​The angle between the line connecting the central point to the points b and c and the horizontal axis delta ;

[0140] In this embodiment, the driving grid-connected converter driving pulse is generated based on the grid-side current derivation value, including:

[0141] The difference between the grid-side current derivation value (dq-axis component, i.e. i q++ and the actual value (dq-axis component, i.e. i d++ ) of the grid-side current is controlled by PI to obtain the grid-side voltage reference value (dq-axis component, i.e. i q and i d ) of the grid-connected converter; u q * and u d * ;

[0142] The driving grid-connected converter driving pulse is generated based on the grid-side voltage reference value of the grid-connected converter, and the grid-connected converter is controlled by using the driving pulse.

[0143] Embodiment 2

[0144] Based on the same inventive concept, the application further provides a grid-connected converter control device based on signal injection, which comprises:

[0145] A first determination module is configured to determine the working mode of the grid-connected converter based on the operating conditions of the grid-connected converter and the new energy system;

[0146] A second determination module is configured to determine the grid-side current derivation value of the grid-connected converter based on the working mode.

[0147] A control module is configured to generate a driving grid-connected converter driving pulse based on the grid-side current derivation value, and control the grid-connected converter by using the driving pulse.

[0148] When the working mode of the grid-connected converter is the dynamic working mode, the second determination module is specifically configured to:

[0149] Determine the virtual power reference value of the grid-connected converter based on the grid-side current and the grid-side voltage of the grid-connected converter.

[0150] Determine the target power angle of the grid-connected converter based on the virtual power of the grid-connected converter.

[0151] The difference between the initial power angle and the target power angle of the grid-connected converter is subjected to a PI controller to obtain an initial derivation value of a three-phase grid-side current of the grid-connected converter, and the initial derivation value of the three-phase grid-side current is subjected to dq conversion to obtain a dq-axis component of an initial derivation value of a grid-side current of the grid-connected converter;

[0152] The dq-axis component of the initial derivation value of the grid-side current of the grid-connected converter is subjected to signal injection to obtain a derivation value of the grid-side current of the grid-connected converter;

[0153] When the working mode of the grid-connected converter is the static working mode, the second determining module is specifically configured to:

[0154] The active boundary trajectory and the reactive boundary trajectory of the grid-connected converter are determined based on the grid-side current and the grid-side voltage of the grid-connected converter;

[0155] The feasible region is calculated based on the active boundary trajectory and the reactive boundary trajectory of the grid-connected converter to obtain a reactive power reference value and a grid-side voltage reference value of the grid-connected converter;

[0156] The derivation value of the grid-side current of the grid-connected converter is obtained by subjecting the difference between the reactive power reference value of the grid-connected converter and an actual value of the reactive power of the grid-connected converter and the difference between the grid-side voltage reference value of the grid-connected converter and an actual value of the grid-side voltage of the grid-connected converter to PI controllers respectively.

[0157] Preferably, the first determining module is specifically configured to:

[0158] When the grid-connected converter fails and the operating state has multiple working conditions, the working mode of the grid-connected converter is the dynamic working mode;

[0159] When the grid-connected converter fails and operates in a single working condition, the working mode of the grid-connected converter is the static working mode.

[0160] Preferably, the virtual power reference value of the grid-connected converter is as follows:

[0161] P v-ref =u g-β i g-v-α -u g-α i g-v-β

[0162] In the above formula, P v-ref is a virtual power reference value of the grid-connected converter, u g-α is a grid-side voltage of the grid-connected converter αaxis quantity, u g-β a grid-forming converter grid-side voltage β axis quantity, i g-v-α a virtual quadrature output current of the grid-forming converter α axis quantity, i g-v-β a virtual quadrature output current of the grid-forming converter β axis quantity.

[0163] Further, the target power angle of the grid-forming converter satisfies:

[0164]

[0165] In the above formula, E is the new energy collection end voltage corresponding to the initial operation condition of the grid-forming converter, E sag a new energy collection end voltage corresponding to the grid-forming converter when the operation state of the grid-forming converter is converted to a target working condition, delta f a target power angle of the grid-forming converter, C a synchronization coefficient, lambda a disturbance amount of the angle, X g a grid-side impedance of the grid-forming converter, P ref a power reference value of the grid-forming converter, U g a grid-side voltage of the grid-forming converter.

[0166] Further, the initial power angle of the grid-forming converter satisfies:

[0167]

[0168] In the above formula, E is the new energy collection end voltage corresponding to the initial operation condition of the grid-forming converter, delta an initial power angle of the grid-forming converter.

[0169] Further, the grid-side current derivation value of the grid-forming converter is as follows:

[0170]

[0171] In the above formula, E is the new energy collection end voltage corresponding to the initial operation condition of the grid-forming converter, i d++ a d-axis component of the grid-side current derivation value of the grid-forming converter, i d+ a d-axis component of the initial derivation value of the grid-side current of the grid-forming converter, i q++ a q-axis component of the grid-side current derivation value of the grid-forming converter, i q+A q-axis component of an initial derivation value of a grid-side current of the grid-forming converter, A A magnitude of the injection signal, omega h A frequency of the injection signal, t A time of the injection signal.

[0172] Preferably, a mathematical model corresponding to the active boundary trajectory of the grid-forming converter is as follows:

[0173]

[0174] In the above formula, ( x u , y u ) are horizontal and vertical coordinates of an end point of the active / reactive boundary trajectory of the grid-forming converter, U g is a grid-side voltage of the grid-forming converter, X g is a grid-side impedance of the grid-forming converter, R g is a grid-side reactance of the grid-forming converter, and P is a grid-side active power of the grid-forming converter.

[0175] Further, a mathematical model corresponding to the reactive boundary trajectory of the grid-forming converter is as follows:

[0176]

[0177] In the above formula, ( x u , y u ) are horizontal and vertical coordinates of an end point of the active / reactive boundary trajectory of the grid-forming converter, U g is a grid-side voltage of the grid-forming converter, X g is a grid-side impedance of the grid-forming converter, R g is a grid-side reactance of the grid-forming converter, and Q is a grid-side reactive power of the grid-forming converter.

[0178] Preferably, the feasible region calculation based on the active boundary trajectory and the reactive boundary trajectory of the grid-forming converter to obtain a reactive power reference value and a grid-side voltage reference value of the grid-forming converter comprises:

[0179] obtaining an intersection point of the active boundary trajectory and the reactive boundary trajectory of the grid-forming converter;

[0180] Select the intersection corresponding to the power angle less than the preset value, obtain the reactive power and voltage corresponding to the intersection, and take the reactive power and voltage as the reactive power reference value and the grid-side voltage reference value of the grid-forming converter.

[0181] Preferably, the generating the driving pulse for driving the grid-forming converter based on the grid-side current derived value comprises:

[0182] The difference between the grid-side current derived value of the grid-forming converter and the actual value of the grid-side current is subjected to PI control to obtain the grid-side voltage reference value of the grid-forming converter.

[0183] The grid-side voltage reference value of the grid-forming converter is used to generate the driving pulse for driving the grid-forming converter, and the driving pulse is used to control the grid-forming converter.

[0184] Embodiment 3

[0185] Based on the same inventive concept, the application further provides a computer device, which comprises a processor and a memory, the memory is used to store a computer program, the computer program comprises program instructions, and the processor is used to execute the program instructions stored in the computer storage device. The processor can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions in the computer storage device to implement a corresponding method process or a corresponding function, so as to implement the steps of the above-mentioned embodiment of the grid-forming converter control method based on signal injection.

[0186] Embodiment 4

[0187] Based on the same inventive concept, the present application also provides a storage device, specifically a computer readable storage device (Memory), which is a memory device in a computer device, used for storing programs and data. It can be understood that the computer readable storage device herein can include the built-in storage device in the computer device, and of course can also include the extended storage device supported by the computer device. The computer readable storage device provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, which can be one or more computer programs (including program codes). It should be noted that the computer readable storage device herein can be a high-speed RAM memory, or a non-volatile memory such as at least one disk memory. One or more instructions stored in the computer readable storage device can be loaded and executed by the processor to implement the steps of the signal injection-based network construction type converter control method in the above embodiment.

[0188] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer usable storage devices (including but not limited to disk storage, CD-ROMs, optical storage devices, etc.) containing computer usable program code.

[0189] The present application is described with reference to flowcharts and / or block diagrams of the method, device (system), and computer program product according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a means for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus that performs the functions specified in one or more flows and / or blocks.

[0190] These computer program instructions can also be stored in a computer readable memory that can guide the computer or other programmable data processing devices to work in a specific way, so that the instructions stored in the computer readable memory produce a product including instruction means, which implements the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocksFigure 1 the function specified in the one or more blocks.

[0191] These computer program instructions can also be loaded into computer or other programmable data processing devices, so that a series of operation steps are performed on the computer or other programmable data processing devices to generate computer-implemented processes, thus the instructions executed on the computer or other programmable data processing devices provide a process for implementing the flow Figure 1 the flow or flows and / or blocks Figure 1 the steps of the function specified in the one or more blocks.

[0192] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit it, although the present application has been described in detail with reference to the above examples, those skilled in the art should understand: the specific embodiments of the present application can still be modified or replaced by the equivalent, without departing from the spirit and scope of the present application, any modification or equivalent replacement, which should be covered within the protection scope of the claims of the present application.

Claims

1. A signal injection based network-forming converter control method, characterized by, The method comprises the following steps: determining the working mode of the grid-forming converter based on the operating conditions of the grid-forming converter and the new energy system; determining the grid-side current derivation value of the grid-forming converter based on the working mode; generating a driving pulse for driving the grid-forming converter based on the grid-side current derivation value, and controlling the grid-forming converter by using the driving pulse; when the working mode of the grid-forming converter is a dynamic working mode, the step of determining the grid-side current derivation value of the grid-forming converter based on the working mode comprises the following steps: determining the virtual power reference value of the grid-forming converter based on the grid-side current and the grid-side voltage of the grid-forming converter; determining the target power angle of the grid-forming converter based on the virtual power of the grid-forming converter; obtaining the initial grid-side three-phase current derivation value of the grid-forming converter by performing PI control on the difference between the initial power angle of the grid-forming converter and the target power angle, and obtaining the dq-axis components of the initial grid-side current derivation value of the grid-forming converter by performing dq conversion on the initial grid-side three-phase current derivation value of the grid-forming converter; respectively injecting signals into the dq-axis components of the initial grid-side current derivation value of the grid-forming converter to obtain the grid-side current derivation value of the grid-forming converter; when the working mode of the grid-forming converter is a static working mode, the step of determining the grid-side current derivation value of the grid-forming converter based on the working mode comprises the following steps: determining the active boundary trajectory and the reactive boundary trajectory of the grid-forming converter based on the grid-side current and the grid-side voltage of the grid-forming converter; performing feasible region calculation based on the active boundary trajectory and the reactive boundary trajectory of the grid-forming converter to obtain the reactive power reference value and the grid-side voltage reference value of the grid-forming converter; respectively performing PI control on the difference between the reactive power reference value of the grid-forming converter and the actual reactive power value of the grid-forming converter and the difference between the grid-side voltage reference value of the grid-forming converter and the actual grid-side voltage value of the grid-forming converter to obtain the grid-side current derivation value of the grid-forming converter.

2. The method of claim 1, wherein, The step of determining the working mode of the grid-forming converter based on the operating conditions of the grid-forming converter and the new energy system comprises the following steps: when the grid-forming converter fails and the operating state has multiple conditions, the working mode of the grid-forming converter is a dynamic working mode; when the grid-forming converter fails and the operating state is a single condition, the working mode of the grid-forming converter is a static working mode.

3. The method of claim 1, wherein, The virtual power reference value of the grid-forming converter is as follows: In the above formula, P v-ref is a virtual power reference value for the grid-forming converter, u g-α is a grid-side voltage of the grid-forming converter α axis, u g-β is a grid-side voltage of the grid-forming converter β axis, i g-v-α is a virtual quadrature output current for the grid-forming converter α axis, i g-v-β is a virtual quadrature output current for the grid-forming converter β axis.

4. The method of claim 3, wherein, The target power angle of the grid-forming converter satisfies: In the above formula, E sag a new energy collection end voltage corresponding to a target working condition when the grid-forming converter operating state is converted, The initial power angle of the grid-forming converter satisfies: f a target power angle of the grid-forming converter, C a synchronization coefficient, The grid-side current derivation value of the grid-forming converter is as follows: a disturbance amount of the angle, X g a grid-side impedance of the grid-forming converter, P ref a power reference value of the grid-forming converter, U g a grid-side voltage of the grid-forming converter.

5. The method of claim 4, wherein, The mathematical model corresponding to the active boundary trajectory of the grid-forming converter is as follows: In the above formula, E is the voltage of the new energy collection end corresponding to the initial operating condition of the network-forming converter, The mathematical model corresponding to the reactive boundary trajectory of the grid-forming converter is as follows: is the initial power angle of the network-forming converter.

6. The method of claim 4, wherein, The step of performing feasible region calculation based on the active boundary trajectory and the reactive boundary trajectory of the grid-forming converter to obtain the reactive power reference value and the grid-side voltage reference value of the grid-forming converter comprises the following steps: In the above formulae, i d++ d-axis component of the grid-side current derived value for the grid-forming converter, i d+ d-axis component of the initial grid-side current derived value for the grid-forming converter, i q++ q-axis component of the grid-side current derived value for the grid-forming converter, i q+ q-axis component of the initial grid-side current derived value for the grid-forming converter, A amplitude of the injection signal, obtaining the intersection of the active boundary trajectory and the reactive boundary trajectory of the grid-forming converter; h frequency of the injection signal, t time of the injection signal.

7. The method of claim 1, wherein, ​ In the above formula, ( x u , y u ) is the horizontal and vertical coordinates of the end point of the active / reactive boundary trajectory of the grid-forming converter, U g is the grid-side voltage of the grid-forming converter, X g is the grid-side impedance of the grid-forming converter, R g is the grid-side reactance of the grid-forming converter, and P is the grid-side active power of the grid-forming converter.

8. The method of claim 7, wherein, ​ In the above formula, ( x u , y u ) is the horizontal and vertical coordinates of the end point of the active / reactive boundary trajectory of the grid-forming converter, U g is the grid-side voltage of the grid-forming converter, X g is the grid-side impedance of the grid-forming converter, R g is the grid-side reactance of the grid-forming converter, and Q is the grid-side reactive power of the grid-forming converter.

9. The method of claim 1, wherein, ​ ​ Select the intersection corresponding to the power angle less than the preset value, obtain the reactive power and voltage corresponding to the intersection, and take the reactive power and voltage as the reactive power reference value and the grid-side voltage reference value of the grid-forming converter.

10. The method of claim 1, wherein, The driving grid-forming converter driving pulse is generated based on the grid-side current derived value, including: The difference between the grid-side current derived value of the grid-forming converter and the actual value of the grid-side current is subjected to PI control to obtain the grid-side voltage reference value of the grid-forming converter; The driving grid-forming converter driving pulse is generated based on the grid-side voltage reference value of the grid-forming converter, and the grid-forming converter is controlled by using the driving pulse.

11. A signal injection based network-forming converter control apparatus, characterized by, The device comprises: The first determination module is configured to determine the working mode of the grid-forming converter based on the operating conditions of the grid-forming converter and the new energy system; The second determination module is configured to determine the grid-side current derived value of the grid-forming converter based on the working mode; The control module is configured to generate the driving grid-forming converter driving pulse based on the grid-side current derived value, and control the grid-forming converter by using the driving pulse; When the working mode of the grid-forming converter is the dynamic working mode, the second determination module is specifically configured to: determine the virtual power reference value of the grid-forming converter based on the grid-side current and the grid-side voltage of the grid-forming converter; determine the target power angle of the grid-forming converter based on the virtual power of the grid-forming converter; subject the difference between the initial power angle of the grid-forming converter and the target power angle to a PI controller to obtain the initial derived value of the grid-side three-phase current of the grid-forming converter, and subject the initial derived value of the grid-side three-phase current of the grid-forming converter to dq conversion to obtain the dq axis components of the initial derived value of the grid-side current of the grid-forming converter; respectively inject signals into the dq axis components of the initial derived value of the grid-side current of the grid-forming converter to obtain the grid-side current derived value of the grid-forming converter; When the working mode of the grid-forming converter is the static working mode, the second determination module is specifically configured to: determine the active boundary trajectory and the reactive boundary trajectory of the grid-forming converter based on the grid-side current and the grid-side voltage of the grid-forming converter; perform feasible region calculation based on the active boundary trajectory and the reactive boundary trajectory of the grid-forming converter to obtain the reactive power reference value and the grid-side voltage reference value of the grid-forming converter; subject the difference between the reactive power reference value of the grid-forming converter and the actual value of the reactive power of the grid-forming converter and the difference between the grid-side voltage reference value of the grid-forming converter and the actual value of the grid-side voltage of the grid-forming converter to PI controllers respectively to obtain the grid-side current derived value of the grid-forming converter.

12. The apparatus of claim 11, wherein, The first determination module is specifically configured to: when the grid-forming converter fails and the operating state has multiple conditions, the working mode of the grid-forming converter is the dynamic working mode; when the grid-forming converter fails and the operating state is a single condition, the working mode of the grid-forming converter is the static working mode.

13. The apparatus of claim 11, wherein, The virtual power reference value of the grid-forming converter is as follows: In the above formulae, P v-ref is a virtual power reference value for the grid-forming converter, u g-α is a grid-side voltage of the grid-forming converter α axis quantity, u g-β is a grid-side voltage of the grid-forming converter β axis quantity, i g-v-α is a virtual quadrature output current for the grid-forming converter α axis quantity, i g-v-β is a virtual quadrature output current for the grid-forming converter β axis quantity.

14. The apparatus of claim 13, wherein, The target power angle of the grid-forming converter satisfies: In the above formula, E sag a new energy collection end voltage corresponding to a target operating condition when the grid-forming converter operating state is converted, The initial power angle of the grid-forming converter satisfies: f a target power angle of the grid-forming converter, C a synchronization coefficient, The grid-side current derived value of the grid-forming converter is as follows: a disturbance amount of the angle, X g a grid-side impedance of the grid-forming converter, P ref a power reference value of the grid-forming converter, U g a grid-side voltage of the grid-forming converter.

15. The apparatus of claim 14, wherein, The mathematical model corresponding to the active boundary trajectory of the grid-forming converter is as follows: In the above formula, E is the voltage of the new energy collection end corresponding to the initial operating condition of the network-forming converter, ​ is the initial power angle of the network-forming converter.

16. The apparatus of claim 14, wherein, ​ In the above formulae, i d++ a d-axis component of the grid-side current derived value for the grid-forming converter, i d+ a d-axis component of the initial grid-side current derived value for the grid-forming converter, i q++ a q-axis component of the grid-side current derived value for the grid-forming converter, i q+ a q-axis component of the initial grid-side current derived value for the grid-forming converter, A a magnitude of the injection signal, ​ h a frequency of the injection signal, t a time of the injection signal.

17. The apparatus of claim 11, wherein, ​ In the above formula, ( x u , y u ) is the horizontal and vertical coordinates of the end point of the active / reactive boundary trajectory of the grid-forming converter, U g is the grid-side voltage of the grid-forming converter, X g is the grid-side impedance of the grid-forming converter, R g is the grid-side reactance of the grid-forming converter, and P is the grid-side active power of the grid-forming converter.

18. The apparatus of claim 17, wherein, A mathematical model corresponding to the reactive boundary locus of the network-forming converter is as follows: In the above formula, ( x u , y u ) is the horizontal and vertical coordinates of the end point of the active / reactive boundary trajectory of the grid-forming converter, U g is the grid-side voltage of the grid-forming converter, X g is the grid-side impedance of the grid-forming converter, R g is the grid-side reactance of the grid-forming converter, and Q is the grid-side reactive power of the grid-forming converter.

19. The apparatus of claim 11, wherein, The feasible region calculation based on the active boundary locus and the reactive boundary locus of the network-forming converter obtains a reactive power reference value and a grid-side voltage reference value of the network-forming converter, and includes: An intersection point of the active boundary locus and the reactive boundary locus of the network-forming converter is obtained; The intersection point corresponding to an angle less than a preset value is selected, a reactive power and a voltage corresponding to the intersection point are obtained, and the reactive power and the voltage are taken as the reactive power reference value and the grid-side voltage reference value of the network-forming converter.

20. The apparatus of claim 11, wherein, The driving pulse for driving the network-forming converter is generated based on the grid-side current derivation value, and includes: A difference between the grid-side current derivation value and an actual value of the grid-side current of the network-forming converter is subjected to PI control to obtain a grid-side voltage reference value of the network-forming converter; The driving pulse for driving the network-forming converter is generated based on the grid-side voltage reference value of the network-forming converter, and the network-forming converter is controlled by using the driving pulse.

21. A computer apparatus comprising: It includes: One or more processors; The processor is configured to execute one or more programs; When the one or more programs are executed by the one or more processors, the signal injection-based network-forming converter control method is implemented.

22. A computer readable storage device, characterized in that, The computer program is stored on the computer readable medium, and when the computer program is executed, the signal injection-based network-forming converter control method is implemented.

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