Network-building inverter power decoupling control method and device based on voltage vector compensation

Abstract

The invention relates to a voltage vector compensation-based power decoupling control method and device for a network-constructed inverter, computer equipment, a storage medium and a computer program product. The method comprises the following steps: acquiring power information of a grid-connected point of the grid-forming inverter, and acquiring voltage vector compensation of the grid-forming inverter; according to the power information of the grid-connected point and voltage vector compensation, obtaining voltage loop control information for the grid-forming inverter; obtaining current inner loop control information for the network-forming inverter according to the output voltage of the network-forming inverter; the output voltage is obtained according to the switching state of a switching device in the grid-forming inverter in the current period; and based on the voltage loop control information and the current inner loop control information, decoupling processing is carried out on the output power of the network-forming inverter. By adopting the method, the problem of output power coupling of the grid-forming inverter can be eliminated, and the capacity utilization rate of the inverter is improved.

Description

Technical Field

[0001] The present application relates to the field of microgrid technology, and in particular to a method, device, computer equipment, storage medium and computer program product for power decoupling control of a grid-connected inverter based on voltage vector compensation. Background Art

[0002] The high proportion of renewable energy and power electronic equipment in the new power system has led to a lack of inertial support in the power grid, which has made the voltage and frequency stability of the new power system face challenges. The grid-type control technology can provide inertial support and transient damping for large power grids, solve the stability problems of voltage and frequency in the power system, realize active perception, active response and active support of the power grid, and improve the local new energy absorption capacity and the power supply quality of the local power grid.

[0003] In the grid-connected system architecture of grid-connected inverters, there is mutual coupling between the active power and reactive power output by the inverter. The mutual influence between the power loops not only deteriorates the dynamic performance of the grid-connected inverter system, but also reduces the control accuracy of the reactive loop and the power sharing accuracy between the grid-connected inverters during island operation. Summary of the invention

[0004] Based on this, it is necessary to provide a power decoupling control method, device, computer equipment, computer-readable storage medium and computer program product for a grid-type inverter based on voltage vector compensation, which can eliminate the output power coupling problem of the grid-type inverter.

[0005] In a first aspect, the present application provides a power decoupling control method for a grid-connected inverter based on voltage vector compensation. The method comprises:

[0006] Obtaining power information of a grid-connected point of a grid-connected inverter, and obtaining voltage vector compensation of the grid-connected inverter;

[0007] Obtaining voltage loop control information for the grid-connected inverter according to the power information of the grid-connected point and the voltage vector compensation;

[0008] According to the output voltage of the grid-type inverter, current inner loop control information for the grid-type inverter is obtained; the output voltage is obtained according to the switching state of the switching device in the grid-type inverter in the current cycle;

[0009] Based on the voltage loop control information and the current inner loop control information, the output power of the grid-connected inverter is decoupled.

[0010] In one embodiment, obtaining the current inner loop control information for the grid-type inverter according to the output voltage of the grid-type inverter includes:

[0011] According to the circuit topology information of the grid-type inverter, a hybrid linear dynamic model of the grid-type inverter is obtained;

[0012] The hybrid linear dynamic model is discretized by a forward Euler method to obtain the single vector current prediction model;

[0013] According to the single-vector current prediction model, current inner-loop control information for the grid-connected inverter is obtained.

[0014] In one embodiment, according to the single-vector current prediction model, the current inner loop control information for the grid-connected inverter is obtained, including:

[0015] Obtaining the next cycle current prediction value of the grid-connected inverter under different preset switching states through the single-vector current prediction model;

[0016] Determine a difference between the predicted value of the current in the next cycle and a reference value of the current in the next cycle of the grid-connected inverter;

[0017] Determining, according to the difference value, a target switching state of the switching device in the next cycle from the different preset switching states;

[0018] Based on the target switch state, current inner loop control information for the grid-connected inverter is obtained.

[0019] In one embodiment, obtaining voltage loop control information for the grid-connected inverter according to the power information of the grid-connected point and the voltage vector compensation includes:

[0020] Obtaining a given reference value of a grid-connected voltage of the grid-connected inverter according to the power information of the grid-connected point and the voltage vector compensation;

[0021] Performing coordinate transformation processing on the given reference value of the grid voltage to obtain the component of the output filter capacitor voltage value of the grid inverter on the αβ axis;

[0022] Based on the components of the output filter capacitor voltage value on the αβ axes, voltage loop control information for the grid-type inverter is obtained.

[0023] In one embodiment, decoupling the output power of the grid-connected inverter is performed based on the voltage loop control information and the current inner loop control information, including:

[0024] Determining a target output filter capacitor voltage value of the grid-connected inverter based on the voltage loop control information;

[0025] Determining a target output filter capacitor current value of the grid-connected inverter based on the current inner loop control information;

[0026] Generating a control signal for the grid-connected inverter according to the target output filter capacitor voltage value and the target output filter capacitor current value;

[0027] According to the control signal, the grid-connected inverter is controlled to decouple the output power.

[0028] In one embodiment, obtaining voltage vector compensation of the grid-connected inverter includes:

[0029] According to the dq-axis component of the voltage at the grid-connected point of the grid-connected inverter in the dq coordinate system, a coupling degree prediction model for the output power of the grid-connected inverter is obtained; the coupling degree prediction model is used to determine the degree of coupling between the active power and the reactive power output by the grid-connected inverter;

[0030] Determining a virtual inductance value of the grid-connected inverter according to the coupling degree prediction model;

[0031] The voltage vector compensation is obtained according to the virtual inductance value and the component of the d-axis of the output current of the grid-type inverter in the dq coordinate system.

[0032] In a second aspect, the present application also provides a power decoupling control device for a grid-type inverter based on voltage vector compensation. The device comprises:

[0033] A parameter acquisition module, used to acquire power information of a grid-connected point of a grid-connected inverter and to acquire voltage vector compensation of the grid-connected inverter;

[0034] A voltage control module, used for obtaining voltage loop control information for the grid-connected inverter according to the power information of the grid-connected point and the voltage vector compensation;

[0035] A current control module, used to obtain current inner loop control information for the grid-type inverter according to the output voltage of the grid-type inverter; the output voltage is obtained according to the switching state of the switching device in the grid-type inverter in the current cycle;

[0036] A decoupling processing module is used to decouple the output power of the grid-connected inverter based on the voltage loop control information and the current inner loop control information.

[0037] In a third aspect, the present application further provides a computer device. The computer device includes a memory and a processor, the memory stores a computer program, and the processor implements the following steps when executing the computer program:

[0038] Obtaining power information of a grid-connected point of a grid-connected inverter, and obtaining voltage vector compensation of the grid-connected inverter;

[0039] Obtaining voltage loop control information for the grid-connected inverter according to the power information of the grid-connected point and the voltage vector compensation;

[0040] According to the output voltage of the grid-type inverter, current inner loop control information for the grid-type inverter is obtained; the output voltage is obtained according to the switching state of the switching device in the grid-type inverter in the current cycle;

[0041] Based on the voltage loop control information and the current inner loop control information, the output power of the grid-connected inverter is decoupled.

[0042] In a fourth aspect, the present application further provides a computer-readable storage medium. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the following steps are implemented:

[0043] Obtaining power information of a grid-connected point of a grid-connected inverter, and obtaining voltage vector compensation of the grid-connected inverter;

[0044] Obtaining voltage loop control information for the grid-connected inverter according to the power information of the grid-connected point and the voltage vector compensation;

[0045] According to the output voltage of the grid-type inverter, current inner loop control information for the grid-type inverter is obtained; the output voltage is obtained according to the switching state of the switching device in the grid-type inverter in the current cycle;

[0046] Based on the voltage loop control information and the current inner loop control information, the output power of the grid-connected inverter is decoupled.

[0047] In a fifth aspect, the present application further provides a computer program product. The computer program product includes a computer program, and when the computer program is executed by a processor, the following steps are implemented:

[0048] Obtaining power information of a grid-connected point of a grid-connected inverter, and obtaining voltage vector compensation of the grid-connected inverter;

[0049] Obtaining voltage loop control information for the grid-connected inverter according to the power information of the grid-connected point and the voltage vector compensation;

[0050] According to the output voltage of the grid-type inverter, current inner loop control information for the grid-type inverter is obtained; the output voltage is obtained according to the switching state of the switching device in the grid-type inverter in the current cycle;

[0051] Based on the voltage loop control information and the current inner loop control information, the output power of the grid-connected inverter is decoupled.

[0052] The above-mentioned power decoupling control method, device, computer equipment, storage medium and computer program product of the grid-type inverter based on voltage vector compensation obtain the power information of the grid-connected point of the grid-type inverter and obtain the voltage vector compensation of the grid-type inverter; obtain the voltage loop control information for the grid-type inverter according to the power information of the grid-connected point and the voltage vector compensation; obtain the current inner loop control information for the grid-type inverter according to the output voltage of the grid-type inverter; the output voltage is obtained according to the switching state of the switching device in the grid-type inverter in the current cycle; based on the voltage loop control information and the current inner loop control information, the output power of the grid-type inverter is decoupled. By adopting this method, the power information of the grid-connected point of the grid-type inverter is quickly obtained, and the inverter is controlled to operate under the condition of no coupling of active power and reactive power through the voltage loop control information and the current inner loop control information, eliminating the output power coupling problem of the grid-type inverter, thereby improving the capacity utilization of the inverter. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 A schematic diagram of a traditional grid-connected inverter system architecture in an embodiment;

[0054] Figure 2 It is a flow chart of a power decoupling control method of a grid-type inverter based on voltage vector compensation in one embodiment;

[0055] Figure 3 It is a schematic diagram of the architecture of a grid-type inverter power decoupling control system based on voltage vector compensation in one embodiment;

[0056] Figure 4 A schematic diagram of a control module of a power decoupling control method for a grid-type inverter based on voltage vector compensation in one embodiment;

[0057] Figure 5 A schematic diagram of voltage loop control in one embodiment;

[0058] Figure 6 A control flow chart for determining a target output filter capacitor current value of a grid-type inverter in one embodiment;

[0059] Figure 7It is a flow chart of a power decoupling control method of a grid-type inverter based on voltage vector compensation in another embodiment;

[0060] Figure 8 It is a structural block diagram of a power decoupling control device of a grid-type inverter based on voltage vector compensation in one embodiment;

[0061] Fig. 9 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0063] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0064] In the related technology, the grid-type inverter can ignore the power coupling caused by the resistance-to-inductance ratio in a high-voltage power grid with inductive line impedance, thereby achieving automatic and independent adjustment of frequency and voltage; however, the power system containing a large amount of renewable energy is faced with complex application scenarios where the lines are resistive and inductive and the power angle varies over a large range. It is impossible to ensure that the conditions for independent control of the active loop and the reactive loop are met, resulting in serious power coupling.

[0065] refer to Figure 1 , is a schematic diagram of the traditional grid-connected inverter system architecture. This system architecture mainly includes four parts, namely, the DC voltage V dc , grid-type inverter, line inductance L l With line resistance R l , and AC grid V g . DC voltage V dc Connected to the next-stage grid-building inverter as its DC input. The grid-building inverter adopts a three-phase full-bridge topology and is connected to the AC grid V through an LC filter. g The LC filter includes the filter inductor L f And the filter capacitor C f LC filter and AC grid V g There is a line inductance L between l With line resistance R l .

[0066] In view of the above problems, the present application proposes a power decoupling control method for a grid-type inverter based on voltage vector compensation, which eliminates the output power coupling problem of the grid-type inverter, thereby improving the inverter capacity utilization.

[0067] In one embodiment, Figure 2 As shown, a power decoupling control method for a grid-type inverter based on voltage vector compensation is provided. In this embodiment, the method includes the following steps:

[0068] Step S201, obtaining power information of a grid-connected point of a grid-connected inverter, and obtaining voltage vector compensation of the grid-connected inverter.

[0069] Step S202: obtaining voltage loop control information for the grid-connected inverter according to the power information of the grid-connected point and the voltage vector compensation.

[0070] Step S203, obtaining current inner loop control information for the grid-type inverter according to the output voltage of the grid-type inverter; the output voltage is obtained according to the switching state of the switching device in the grid-type inverter in the current cycle.

[0071] Step S204: decoupling the output power of the grid-connected inverter based on the voltage loop control information and the current inner loop control information.

[0072] Specifically, refer to Figure 3 , is a schematic diagram of the architecture of a grid-type inverter power decoupling control system based on voltage vector compensation provided in an embodiment of the present application. Figure 3 As shown, firstly, the output power extraction module connected to the grid point obtains the relevant voltage and current input, and calculates the total load power in real time. Then, the grid control module with voltage vector compensation calculates the information of the given voltage of the grid in real time. Then, the SPWN control signal (Sine pulse width modulation) is generated through the voltage and current inner loop control module, and the SPWN module is output to generate the drive signal according to the SPWM control signal through the SPWN module. Finally, the drive signal acts on Figure 3 The grid-connected inverter in the system is controlled to decouple the output power (active power and reactive power).

[0073] The decoupling control process for grid-connected inverters mainly consists of three parts: active loop control, reactive loop control, voltage vector control loop branch and coordinate transformation module. Figure 4 The control module diagram of the power decoupling control method of the grid-connected inverter based on voltage vector compensation is shown in Figure 4 In, P e , Q eThe grid point power extraction module is the real-time measured active power and reactive power of the grid point, P set The grid-connected inverter outputs active power given reference value, Q set The reference value of reactive power output of grid-connected inverter is given, D p , J, D q are the droop coefficient and virtual inertia coefficient of the active loop, and the droop coefficient of the reactive loop, ω n ,ω,V n They are the rated angular frequency, actual angular frequency and rated output voltage amplitude of the output voltage. cd 、V cq , δ are the components and phase angles of the given voltage in the dq coordinate system respectively. The three-phase voltage V can be generated through the coordinate transformation module. c_abc .

[0074] Among them, the expression of the coordinate transformation module (dq to abc) is as follows:

[0075]

[0076] In the above-mentioned power decoupling control method of the grid-type inverter based on voltage vector compensation, the power information of the grid-connected point of the grid-type inverter is obtained, and the voltage vector compensation of the grid-type inverter is obtained; according to the power information of the grid-connected point and the voltage vector compensation, the voltage loop control information for the grid-type inverter is obtained; according to the output voltage of the grid-type inverter, the current inner loop control information for the grid-type inverter is obtained; the output voltage is obtained according to the switching state of the switching device in the grid-type inverter in the current cycle; based on the voltage loop control information and the current inner loop control information, the output power of the grid-type inverter is decoupled. By adopting this method, the power information of the grid-connected point of the grid-type inverter is quickly obtained, and the inverter is controlled to operate under the condition of no coupling of active power and reactive power through the voltage loop control information and the current inner loop control information, eliminating the output power coupling problem of the grid-type inverter, thereby improving the inverter capacity utilization rate.

[0077] In one embodiment, the above step S203 obtains the current inner-loop control information for the meshed inverter according to the output voltage of the meshed inverter, and specifically includes the following contents: obtaining a hybrid linear dynamic model of the meshed inverter according to the circuit topology information of the meshed inverter; discretizing the hybrid linear dynamic model through the forward Euler method to obtain a single-vector current prediction model; obtaining the current inner-loop control information for the meshed inverter according to the single-vector current prediction model.

[0078] Specifically, single vector current predictive control can be used in the current inner loop of the grid-type inverter. First, the corresponding MLD (Mixed Linear Dynamic) model differential equation is obtained according to the circuit topology, that is, the mixed linear dynamic model of the grid-type inverter is obtained:

[0079]

[0080] Among them, R f is the equivalent resistance of the output filter inductor of the grid-type inverter, L f is the output filter inductor, V a 、V b 、V c is the output voltage of the inverter, V ca 、V cb 、V cc is the voltage on the filter capacitor.

[0081] The hybrid linear dynamic model is discretized using the forward Euler method to obtain the single vector current prediction model of the grid-type inverter:

[0082]

[0083] Then, according to the single vector current prediction model, the current inner loop control information for the grid-type inverter is obtained. The current inner loop control information can be a control signal describing the target switching state of the switching device in the grid-type inverter in the next cycle, or a control signal describing the current required for the grid-type inverter output.

[0084] Among them, the output voltage V of the grid-type inverter in the single vector current prediction model formula is a 、V b 、V c It is calculated based on the switch state. The switch state is defined as follows:

[0085]

[0086]

[0087]

[0088] The output voltages in all switching states are shown in Table 1:

[0089] Table 1

[0090]

[0091] In another implementation, the output voltage of the grid-type inverter in the αβ coordinate system can also be calculated according to the switch state:

[0092]

[0093] Then, the single vector current prediction model of the grid-type inverter in the αβ coordinate system can be obtained as follows:

[0094]

[0095] In this embodiment, the current inner loop control information for the grid-type inverter is generated through a single-vector current prediction model, which can control the opening and closing of the switching devices in the grid-type inverter, thereby achieving precise control of the output current of the grid-type inverter, which helps to improve the decoupling effect of the output power of the grid-type inverter.

[0096] In one embodiment, according to a single-vector current prediction model, current inner-loop control information for a grid-type inverter is obtained, specifically including the following contents: through a single-vector current prediction model, a next-cycle current prediction value of the grid-type inverter under different preset switching states is obtained; a difference value between the next-cycle current prediction value and a next-cycle current reference value of the grid-type inverter is determined; according to the difference value, a target switching state of the switching device in the next cycle is determined from different preset switching states; based on the target switching state, the current inner-loop control information for the grid-type inverter is obtained.

[0097] The switch state is used to represent the working state of the switch device. For example, the switch state includes on and off.

[0098] Specifically, the single-vector current prediction model is used to predict the next cycle current prediction value of the grid-type inverter under different preset switching states, and then the optimal target switching state of the switching device in the grid-type inverter in the next cycle is screened out according to the proximity between the next cycle current prediction value and the next cycle current reference value of the grid-type inverter. Therefore, a value function needs to be set to measure the gap between the predicted value and the reference value. The value function used in this application is as follows:

[0099]

[0100] Where I d * and I q * They are the d-axis and q-axis components of the current reference value respectively.

[0101] In practical applications, the smaller the value of the cost function is, the closer the predicted current value of the next cycle is to the reference current value of the next cycle, and the better the corresponding preset switch state is, so that the optimal preset switch state can be selected as the target switch state. Based on the target switch state, the reference current of the grid-forming inverter and other current inner loop control information for the grid-forming inverter are further set.

[0102] In this embodiment, the target switching state of the switching device in the next cycle is determined by the difference between the next cycle current prediction value and the next cycle current reference value of the grid-type inverter; thereby, based on the target switching state, the current inner loop control information of the grid-type inverter is accurately determined, thereby controlling the switching device of the grid-type inverter to enable the optimal switching state, effectively improving the decoupling effect of the output power of the grid-type inverter.

[0103] In one embodiment, the above step S202 obtains voltage loop control information for the grid-connected inverter based on the power information and voltage vector compensation of the grid-connected point, and specifically includes the following contents: obtaining a given reference value of the grid-connected voltage of the grid-connected inverter based on the power information and voltage vector compensation of the grid-connected point; performing coordinate transformation processing on the given reference value of the grid-connected voltage to obtain a component of the output filter capacitor voltage value of the grid-connected inverter on the αβ axis; obtaining the voltage loop control information for the grid-connected inverter based on the component of the output filter capacitor voltage value on the αβ axis.

[0104] Figure 5 Specifically, the grid voltage reference value V of the grid-connected inverter is calculated based on the power information of the grid-connected point and the voltage vector compensation. c_abc ; Afterwards, the given reference value of the grid voltage can be subjected to coordinate transformation (abc to αβ) to obtain the component of the output filter capacitor voltage value of the grid inverter on the αβ axis; based on the component of the output filter capacitor voltage value on the αβ axis, the open-loop transfer function of the voltage loop is obtained; through the open-loop transfer function, the voltage loop control information for the grid inverter is obtained.

[0105] exist Figure 5 In, V c_abc is the given reference value of the grid voltage, K p The overall gain of the PR controller can be adjusted, K r The resonance peak gain can be adjusted, and the resonance frequency band width can be adjusted at the same time, ω c The width of the resonant frequency band can be adjusted, and the resonant peak gain can be adjusted at the same time. ω0 is the resonant frequency point. p With k r are the control parameters of the controller voltage loop, I cα ,I cβ is the current value of the grid inverter output filter capacitor on the αβ axis, V cα 、V cβ is the voltage component of the grid inverter output filter capacitor on the αβ axis, U dc is the actual value of the DC bus voltage, and the open-loop transfer function of the voltage loop is as follows:

[0106]

[0107] Among them C dc is the output capacitance value.

[0108] In this embodiment, based on the given reference value of the grid voltage, voltage loop control information for the grid-type inverter is generated to achieve precise control of the voltage loop of the grid-type inverter, thereby adjusting the coupling between the active power and reactive power of the grid-type inverter, effectively improving the decoupling effect of the output power of the grid-type inverter.

[0109] In one embodiment, the above-mentioned step S204 decouples the output power of the meshed inverter based on the voltage loop control information and the current inner loop control information, and specifically includes the following contents: based on the voltage loop control information, determining the target output filter capacitor voltage value of the meshed inverter; based on the current inner loop control information, determining the target output filter capacitor current value of the meshed inverter; according to the target output filter capacitor voltage value and the target output filter capacitor current value, generating a control signal for the meshed inverter; according to the control signal, controlling the meshed inverter to decouple the output power.

[0110] Specifically, by setting the reference current, the grid-connected inverter can output the required current. The control flow chart is as follows: Figure 6 As shown. By setting the initial parameters m, n, and g, the value function under different preset switch states is calculated, and finally the target output filter capacitor current value of the grid-type inverter is determined according to the switch state corresponding to the parameter m. Further, according to the voltage loop control information, the target output filter capacitor voltage value of the grid-type inverter is determined; and then the control signal corresponding to the target output filter capacitor voltage value and the target output filter capacitor current value is adopted to control the grid-type inverter to decouple the active power and reactive power.

[0111] In this embodiment, based on the given reference value of the grid voltage, voltage loop control information for the grid-type inverter is generated to achieve precise control of the voltage loop of the grid-type inverter, thereby adjusting the coupling between the active power and reactive power of the grid-type inverter, effectively improving the decoupling effect of the output power of the grid-type inverter.

[0112] In one embodiment, the above step S201, obtaining the power information of the grid-connected point of the grid-connected inverter, specifically includes the following contents: according to the component of the voltage of the grid-connected point of the grid-connected inverter on the dq axis in the dq coordinate system, obtaining a coupling degree prediction model for the output power of the grid-connected inverter; the coupling degree prediction model is used to judge the degree of coupling between the active power and the reactive power output by the grid-connected inverter; according to the coupling degree prediction model, determining the virtual inductance value of the grid-connected inverter; according to the virtual inductance value and the component of the output current of the grid-connected inverter on the d axis in the dq coordinate system, obtaining voltage vector compensation.

[0113] First, determine the power information of the grid-connected point of the grid-connected inverter, and then use the power information of the grid-connected point to calculate the voltage vector compensation. abc , I abc The mathematical expression converted into the stationary coordinate system is:

[0114]

[0115]

[0116] The calculation method of the power information of the grid connection point is as follows:

[0117]

[0118] V α 、V β ,I α ,I β They are the components of voltage and current at the grid-connected point in the stationary coordinate system respectively. The above power calculation formula can be used to obtain the real-time active power of the grid-connected inverter.

[0119] When a grid-type inverter is operated with an αβ unbalanced load, it is often necessary to control its three-phase output voltage to be sinusoidally balanced to provide high-quality power supply to the load. Assume that the three-phase output voltage u a 、u b 、u c Sine balance, which contains only positive sequence components, is shown in the following equation:

[0120]

[0121] When the load is unbalanced, the three-phase output current i a 、i b 、i c It will consist of positive and negative sequence current components, as shown in the following equation:

[0122]

[0123] The output voltage u a 、u b、u c With current i a 、i b 、i c Transformed into the dq coordinate system, the output voltage u a Aligned with the d-axis, the expressions for voltage and current are as follows:

[0124]

[0125] Where: U is the effective value of the positive sequence component of the output voltage; I + ,I - are the effective values ​​of the positive and negative sequence components of the output current respectively; Ф is the initial phase of the output voltage; Ф i+ , Ф i- are the initial phases of the positive and negative sequence components of the output current respectively; ω is the fundamental angular frequency.

[0126] At this time, the calculation expression of the instantaneous power output from the grid-connected inverter to the grid is:

[0127]

[0128] Among them: p1 is the average value component of the output power, which is constant; p2 is the multiple pulsation component of the output power, which is zero when the load is balanced. p1 and p2 can be expressed as:

[0129]

[0130] It can be seen from the power expression p2 that since the output current contains harmonic components and negative sequence components, the output power also contains multiple pulsating components.

[0131] Furthermore, in the traditional grid-connected inverter system, the output active power P out and reactive power Q out The expression is as follows:

[0132]

[0133] In the above formula, V cd 、V cq are the components of the voltage at the grid-connected point of the grid-connected inverter on the dq axis, i od 、i oq are the components of the voltage at the grid-connected point of the grid-connected inverter on the dq axis. To give the equivalent small signal model of the grid-connected inverter under power decoupling control based on voltage vector compensation, the key is to give P out With Q out The specific expression of V cd With V cq It can be expressed as:

[0134]

[0135] Through the traditional grid-connected inverter system, V c With AC grid V g The expression between:

[0136]

[0137] Where θ' is the phase angle difference between the output voltage of the grid-type inverter and the grid voltage after the power decoupling control of the grid-type inverter with voltage vector compensation. Combining the above two expressions, we can get:

[0138]

[0139] in,

[0140]

[0141] From this, we can get the expression of output active power and reactive power in the traditional grid-connected inverter system:

[0142]

[0143] By linearizing the above equation near the equilibrium point, the equivalent mathematical model of the grid-connected inverter under power decoupling control based on voltage vector compensation can be derived:

[0144]

[0145] in,

[0146]

[0147] The θ' in the formula can be calculated as:

[0148]

[0149] In the formula, φ is the output power angle. The coupling coefficient ξ is defined to determine the coupling degree between the output active power and reactive power. The expression is:

[0150]

[0151] By selecting different virtual inductance parameters and substituting them into the ξ expression, the virtual inductance parameter that makes the ξ value closest to 0 is selected. This parameter is the virtual inductance value required for power decoupling. Then, based on the virtual inductance value, the virtual reactance value X of the grid-connected inverter is calculated. v .

[0152] The d-axis component I of the grid-connected inverter output current in the dq coordinate system is obtained by measuring the grid connection point. od Based on Xv and I od , calculate the voltage vector compensation value Δv lv_q , whose expression is as follows:

[0153]

[0154] Among them, I od The calculation expression is as follows:

[0155]

[0156] Where ωt is the phase size extracted by the phase-locked loop.

[0157] In this embodiment, a coupling degree prediction model for the output power of the grid-connected inverter is obtained according to the component of the voltage of the grid-connected point of the grid-connected inverter on the dq axis in the dq coordinate system; the coupling degree prediction model is used to judge the degree of coupling between the active power and the reactive power output by the grid-connected inverter; according to the coupling degree prediction model, the virtual inductance value of the grid-connected inverter is determined; according to the virtual inductance value and the component of the output current of the grid-connected inverter on the d axis in the dq coordinate system, the voltage vector compensation is obtained.

[0158] In one embodiment, Figure 7 As shown, another power decoupling control method of a grid-connected inverter based on voltage vector compensation is provided. In this embodiment, the method includes the following steps:

[0159] Step S701, obtaining power information of a grid-connected point of a grid-connected inverter, and obtaining voltage vector compensation of the grid-connected inverter.

[0160] Step S702: obtaining a given reference value of a grid-connected voltage of the grid-connected inverter according to the power information of the grid-connected point and the voltage vector compensation.

[0161] Step S703, coordinate transformation processing is performed on the given reference value of the grid voltage to obtain the component of the output filter capacitor voltage value of the grid inverter on the αβ axis.

[0162] Step S704: obtaining voltage loop control information for the grid-connected inverter based on the components of the output filter capacitor voltage value on the αβ axes.

[0163] Step S705 : obtaining a hybrid linear dynamic model of the grid-type inverter according to the circuit topology information of the grid-type inverter.

[0164] Step S706 , discretizing the hybrid linear dynamic model through a forward Euler method to obtain the single vector current prediction model.

[0165] Step S707: obtaining current inner loop control information for the grid-connected inverter according to the single-vector current prediction model.

[0166] Step S708: Decoupling the output power of the grid-connected inverter based on the voltage loop control information and the current inner loop control information.

[0167] The above-mentioned power decoupling control method of the grid-type inverter based on voltage vector compensation can achieve the following beneficial effects: it realizes the rapid acquisition of the power information of the grid-connected point of the grid-type inverter, and also controls the inverter to operate under the condition of active power and reactive power without coupling through voltage loop control information and current inner loop control information, thereby eliminating the output power coupling problem of the grid-type inverter, thereby improving the inverter capacity utilization.

[0168] In order to more clearly illustrate the power decoupling control method of the grid-type inverter based on voltage vector compensation provided by the embodiment of the present disclosure, the power decoupling control method of the grid-type inverter based on voltage vector compensation is specifically described below with a specific embodiment. Another power decoupling control method of the grid-type inverter based on voltage vector compensation is provided, which specifically includes the following contents: first, the total load power is calculated in real time through the voltage and current input of the grid-connected point power extraction module, and the amplitude and phase angle information of the grid-connected given voltage are calculated in real time through the grid-connected control module with voltage vector compensation. Then, the opening and closing of the switching devices in the grid-connected inverter are controlled by the dual-loop follower module. The rapid acquisition of grid-connected point power is realized, and the grid voltage is accurately given without coupling of the inverter output active power and reactive power, which can eventually eliminate the output power decoupling of the grid-connected inverter and improve the inverter capacity utilization rate.

[0169] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0170] Based on the same inventive concept, the embodiment of the present application also provides a power decoupling control device for a grid-type inverter based on voltage vector compensation for implementing the power decoupling control method for a grid-type inverter based on voltage vector compensation. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations of one or more embodiments of the power decoupling control device for a grid-type inverter based on voltage vector compensation provided below can be referred to the limitations of the power decoupling control method for a grid-type inverter based on voltage vector compensation above, and will not be repeated here.

[0171] In one embodiment, Figure 8 As shown, a grid-type inverter power decoupling control device 800 based on voltage vector compensation is provided, comprising: a parameter acquisition module 801, a voltage control module 802, a current control module 803 and a decoupling processing module 804, wherein:

[0172] The parameter acquisition module 801 is used to acquire the power information of the grid connection point of the grid-connected inverter and acquire the voltage vector compensation of the grid-connected inverter.

[0173] The voltage control module 802 is used to obtain voltage loop control information for the grid-connected inverter according to the power information of the grid-connected point and the voltage vector compensation.

[0174] The current control module 803 is used to obtain the current inner loop control information for the grid-type inverter according to the output voltage of the grid-type inverter; the output voltage is obtained according to the switching state of the switching device in the grid-type inverter in the current cycle.

[0175] The decoupling processing module 804 is used to perform decoupling processing on the output power of the grid-connected inverter based on the voltage loop control information and the current inner loop control information.

[0176] In one embodiment, the current control module 803 is also used to obtain a hybrid linear dynamic model of the meshed inverter based on the circuit topology information of the meshed inverter; the hybrid linear dynamic model is discretized by the forward Euler method to obtain a single-vector current prediction model; and the current inner-loop control information for the meshed inverter is obtained based on the single-vector current prediction model.

[0177] In one embodiment, the power decoupling control device 800 of a grid-type inverter based on voltage vector compensation also includes a switch control module, which is used to obtain a next-cycle current prediction value of the grid-type inverter under different preset switching states through a single-vector current prediction model; determine the difference between the next-cycle current prediction value and the next-cycle current reference value of the grid-type inverter; according to the difference, determine the target switching state of the switching device in the next cycle from different preset switching states; and obtain current inner-loop control information for the grid-type inverter based on the target switching state.

[0178] In one embodiment, the voltage control module 802 is also used to obtain a given reference value of the grid-connected voltage of the grid-connected inverter according to the power information of the grid-connected point and the voltage vector compensation; perform coordinate transformation processing on the given reference value of the grid-connected voltage to obtain the component of the output filter capacitor voltage value of the grid-connected inverter on the αβ axis; and obtain voltage loop control information for the grid-connected inverter based on the component of the output filter capacitor voltage value on the αβ axis.

[0179] In one embodiment, the decoupling processing module 804 is also used to determine the target output filter capacitor voltage value of the meshed inverter based on the voltage loop control information; determine the target output filter capacitor current value of the meshed inverter based on the current inner loop control information; generate a control signal for the meshed inverter according to the target output filter capacitor voltage value and the target output filter capacitor current value; and control the meshed inverter to decouple the output power according to the control signal.

[0180] In one embodiment, the parameter acquisition module 801 is also used to obtain a coupling degree prediction model for the output power of the grid-connected inverter based on the component of the voltage of the grid-connected point of the grid-connected inverter on the dq axis in the dq coordinate system; the coupling degree prediction model is used to determine the degree of coupling between the active power and the reactive power output by the grid-connected inverter; according to the coupling degree prediction model, the virtual inductance value of the grid-connected inverter is determined; and the voltage vector compensation is obtained based on the virtual inductance value and the component of the output current of the grid-connected inverter on the d axis in the dq coordinate system.

[0181] Each module in the above-mentioned grid-type inverter power decoupling control device based on voltage vector compensation can be implemented in whole or in part by software, hardware and a combination thereof. Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

[0182] In one embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as follows: Fig. 9As shown. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface, the display unit and the input device are connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and the external device. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be realized through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a power decoupling control method of a grid-type inverter based on voltage vector compensation is realized. The display unit of the computer device is used to form a visually visible picture, which can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the computer device shell, or an external keyboard, touchpad or mouse.

[0183] Those skilled in the art will understand that Fig. 9 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0184] In one embodiment, a computer device is further provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above method embodiments when executing the computer program.

[0185] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0186] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0187] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0188] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0189] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A power decoupling control method for a grid-connected inverter based on voltage vector compensation, characterized in that: The method comprises: Obtaining power information of a grid-connected point of a grid-connected inverter, and obtaining voltage vector compensation of the grid-connected inverter; Obtaining voltage loop control information for the grid-connected inverter according to the power information of the grid-connected point and the voltage vector compensation; According to the output voltage of the grid-type inverter, current inner loop control information for the grid-type inverter is obtained; the output voltage is obtained according to the switching state of the switching device in the grid-type inverter in the current cycle; Based on the voltage loop control information and the current inner loop control information, the output power of the grid-connected inverter is decoupled.

2. The method according to claim 1, characterized in that The step of obtaining the current inner loop control information for the grid-type inverter according to the output voltage of the grid-type inverter includes: According to the circuit topology information of the grid-type inverter, a hybrid linear dynamic model of the grid-type inverter is obtained; The hybrid linear dynamic model is discretized by a forward Euler method to obtain the single vector current prediction model; According to the single-vector current prediction model, current inner-loop control information for the grid-connected inverter is obtained.

3. The method according to claim 2, characterized in that The step of obtaining the current inner loop control information for the grid-connected inverter according to the single-vector current prediction model includes: Obtaining the next cycle current prediction value of the grid-connected inverter under different preset switching states through the single-vector current prediction model; Determine a difference between the predicted value of the current in the next cycle and a reference value of the current in the next cycle of the grid-connected inverter; Determining, according to the difference value, a target switching state of the switching device in the next cycle from among the different preset switching states; Based on the target switch state, current inner loop control information for the grid-connected inverter is obtained.

4. The method according to claim 1, characterized in that The step of obtaining voltage loop control information for the grid-connected inverter according to the power information of the grid-connected point and the voltage vector compensation includes: Obtaining a given reference value of a grid-connected voltage of the grid-connected inverter according to the power information of the grid-connected point and the voltage vector compensation; Performing coordinate transformation processing on the given reference value of the grid voltage to obtain the component of the output filter capacitor voltage value of the grid inverter on the αβ axis; Based on the components of the output filter capacitor voltage value on the αβ axes, voltage loop control information for the grid-type inverter is obtained.

5. The method according to claim 1, characterized in that The decoupling process of the output power of the grid-type inverter based on the voltage loop control information and the current inner loop control information includes: Determining a target output filter capacitor voltage value of the grid-connected inverter based on the voltage loop control information; Determining a target output filter capacitor current value of the grid-connected inverter based on the current inner loop control information; Generating a control signal for the grid-connected inverter according to the target output filter capacitor voltage value and the target output filter capacitor current value; According to the control signal, the grid-connected inverter is controlled to decouple the output power.

6. The method according to claim 1, characterized in that The obtaining of voltage vector compensation of the grid-connected inverter includes: According to the dq-axis component of the voltage at the grid-connected point of the grid-connected inverter in the dq coordinate system, a coupling degree prediction model for the output power of the grid-connected inverter is obtained; the coupling degree prediction model is used to determine the degree of coupling between the active power and the reactive power output by the grid-connected inverter; Determining a virtual inductance value of the grid-connected inverter according to the coupling degree prediction model; The voltage vector compensation is obtained according to the virtual inductance value and the component of the d-axis of the output current of the grid-type inverter in the dq coordinate system.

7. A grid-type inverter power decoupling control device based on voltage vector compensation, characterized in that: The device comprises: A parameter acquisition module, used to acquire power information of a grid-connected point of a grid-connected inverter and to acquire voltage vector compensation of the grid-connected inverter; A voltage control module, used for obtaining voltage loop control information for the grid-connected inverter according to the power information of the grid-connected point and the voltage vector compensation; A current control module, used to obtain current inner loop control information for the grid-type inverter according to the output voltage of the grid-type inverter; the output voltage is obtained according to the switching state of the switching device in the grid-type inverter in the current cycle; A decoupling processing module is used to decouple the output power of the grid-connected inverter based on the voltage loop control information and the current inner loop control information.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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