Rapid phase locking processing method and device based on phase angle compensation

Abstract

The invention discloses a fast phase locking processing method and device based on phase angle compensation. The method comprises the following steps: acquiring a three-phase voltage of a power grid through a voltage sensor in the power grid; performing coordinate transformation on the three-phase voltage to obtain a d-axis component voltage and a q-axis component voltage; processing the q-axis component voltage by using a proportional-integral (PI) controller to obtain a frequency deviation value; superposing the frequency deviation value and the rated frequency value to obtain a superposition value; the superposition quantity is subjected to integral processing and then superposed with a compensation angle, the voltage phase angle of the power grid is obtained, and the compensation angle is obtained according to the d-axis component voltage and the q-axis component voltage; and controlling a current loop of the power grid by using the voltage phase angle so as to perform rapid phase locking processing on the power grid. According to the invention, the technical problem that a power grid system may be off-grid due to bus overvoltage caused by the fact that a current vector and a voltage vector of an inverter cannot be synchronized for a long time during large-angle phase jump in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of inverter control, and in particular to a fast phase-locking processing method and device based on phase angle compensation. Background Art

[0002] As the interface between renewable energy and the power grid, the control performance of the grid-connected inverter is crucial to the stability of the power system. At present, in industrial sites, the grid-connected inverter mainly adopts a grid-following control architecture, that is, it generates a current reference value after phase locking according to the voltage angle, and then outputs the desired active power and reactive power. The key function is phase locking. The typical system block diagram of the grid-following grid-connected inverter is as follows: Figure 1 ( Figure 1 The system block diagram of the grid-connected inverter according to the prior art is shown in FIG. 1 , in which the terminal voltage generates angle information through a phase-locked loop (PLL) as the reference angle of the current loop dq / abc conversion. The simplified equivalent block diagram of the grid-connected inverter is shown in FIG. Figure 2 As shown ( Figure 2 is a simplified block diagram of a grid-following inverter according to an embodiment of the present invention), the angle information generated by the phase-locked loop directly determines the active power and reactive power values ​​injected into the PCC point by the system.

[0003] The phase-locked loop is a key functional module of the grid-following inverter. For the grid-following inverter, its essence is to control the inverter into a controlled current source to inject active power and reactive power into the grid. Among them, it is important to use the phase-locked loop to accurately obtain the phase of the grid voltage. A typical phase-locked loop solution is as follows: Figure 3 ( Figure 3 It is a system structure diagram of a typical phase-locked loop according to the prior art); Figure 3 The equivalent control block diagram is as follows Figure 4 As shown ( Figure 4 is the above Figure 3 The equivalent control block diagram of the phase-locked loop is shown in Figure 1, where δ is the phase difference between the phase angle output by the PLL and the actual phase angle of the grid voltage, and Vg is the modulus of the three-phase grid voltage vector. When the grid voltage has a phase jump, the phase-locked loop will gradually reduce the phase angle difference δ to zero through closed-loop regulation to achieve synchronization. Figure 2 It can be seen that the traditional phase-locked loop is essentially a second-order system, and its damping coefficient And the adjustment time ts expression is as follows: In actual sites, in order to adapt to the weak power grid scenario, the system's regulation bandwidth is usually set very small, which results in a slow response speed of the system. A set of typical phase-locked loop parameters are given below, as shown in Table 1 (Typical parameters of phase-locked loops in actual sites):

[0004] Table 1

[0005]

[0006]

[0007] According to the parameters in Table 1, the adjustment time of the phase-locked loop can be calculated to be 14.2ms. In practice, in order to suppress the interference of harmonics, a low-pass filter or a band-pass filter is usually added, which will lead to a longer adjustment time of the phase-locked loop.

[0008] When the grid is operating normally or a fault occurs only due to a change in voltage amplitude, the phase of the grid voltage does not change suddenly. The slower phase-locked loop can continuously lock the phase of the grid voltage, so that the inverter can continue to output the desired active power and reactive power according to instructions.

[0009] When the grid voltage phase jumps, a large phase difference suddenly appears between the grid voltage phase angle and the phase angle of the PLL output. If the phase-locked loop adjustment time is long, the current vector and the grid voltage vector in the grid-following inverter, which rely on the angle orientation provided by the phase-locked loop, will be in a non-aligned state for a long time, which may cause power backflow and DC side voltage instability in the system, causing the inverter to shut down. When the inverter is set to the unity power factor working state, such as Figure 3 As shown, the current vector I (OB vector) and the grid voltage vector V g (OA vector) directions coincide, and the system only outputs active power.

[0010] When a phase jump fault occurs in the grid voltage, such as Figure 5 and Figure 6 ( Figure 5 It is a voltage and current vector relationship diagram under normal working conditions in the prior art. Figure 6 As shown in the schematic diagram of the voltage-current vector relationship after a grid voltage phase jump fault in the prior art, the grid voltage vector will suddenly jump to the OA1 direction. Since the output of the phase-locked loop cannot change suddenly, the current vector is still along the OB direction at the time of the fault. As the phase-locked loop is adjusted, the phase angle difference gradually decreases, and the current vector gradually rotates to the OB1 direction and regains synchronization with the voltage vector. It is worth noting that during the phase-locked loop adjustment process, the phase angle difference between the voltage vector and the current vector may be an obtuse angle, which means that the inverter may be in a rectification state during the adjustment process, absorbing energy from the grid. This may cause the DC side voltage to rise suddenly and trigger the overvoltage protection.

[0011] The fluctuation of the DC side voltage depends on the integral of the DC side absorbed power over the regulation time. In order to adapt to the weak grid characteristics on site and avoid sub / super synchronous oscillation, the existing phase-locked schemes often have a very low PLL bandwidth, which results in a too long PLL regulation speed. Therefore, the system is very likely to be disconnected from the grid due to the long-term inability of the inverter current vector and voltage vector to synchronize when there is a large phase jump, causing the busbar to be over-voltage.

[0012] To address the above-mentioned problems, no effective solution has been proposed yet. Summary of the invention

[0013] The embodiments of the present invention provide a fast phase-locking processing method and device based on phase angle compensation, so as to at least solve the technical problem in the related art that the power grid system may be disconnected from the grid due to the long-term inability to synchronize the inverter current vector and voltage vector when a large-angle phase jump occurs, causing bus overvoltage.

[0014] According to one aspect of an embodiment of the present invention, a fast phase-locking processing method based on phase angle compensation is provided, comprising: acquiring the three-phase voltage of the power grid through a voltage sensor in the power grid; performing coordinate transformation on the three-phase voltage to obtain a d-axis component voltage and a q-axis component voltage; processing the q-axis component voltage using a proportional-integral (PI) controller to obtain a frequency deviation; superimposing the frequency deviation and a rated frequency value to obtain a superimposed amount; integrating the superimposed amount and superimposing it with a compensation angle to obtain a voltage phase angle of the power grid, wherein the compensation angle is obtained based on the d-axis component voltage and the q-axis component voltage; and controlling the current loop of the power grid using the voltage phase angle to perform fast phase-locking processing on the power grid.

[0015] Optionally, performing coordinate transformation on the three-phase voltage to obtain a d-axis component voltage and a q-axis component voltage includes: obtaining an initial phase angle of the current loop; and obtaining the d-axis component voltage and the q-axis component voltage according to the initial phase angle and the three-phase voltage using a first formula, wherein the first formula is: V ga 、V gb and V gc represents the three-phase voltage, θ represents the initial phase angle, V gdt represents the d-axis component voltage, V gqt represents the q-axis component voltage.

[0016] Optionally, using a proportional-integral PI controller to process the q-axis component voltage to obtain a frequency deviation comprises: using a proportional-integral PI controller to process the q-axis component voltage to obtain the frequency deviation through a second formula, wherein the second formula is: Δω represents the frequency deviation, V gqtrepresents the q-axis component voltage, k p represents the proportional coefficient of the PI controller, k i represents the integral coefficient of the PI controller, and s represents the operator in Laplace transform.

[0017] Optionally, integrating the superimposed amount and superimposing the superimposed amount with the compensation angle to obtain the voltage phase angle of the power grid includes: integrating the superimposed amount and superimposing the superimposed amount with the compensation angle by a third formula to obtain the voltage phase angle of the power grid, wherein the third formula is: θ represents the voltage phase angle, Δω represents the frequency deviation, ω n Indicates the rated frequency value, represents the compensation angle.

[0018] Optionally, before integrating the superposition amount and superimposing it with the compensation angle to obtain the voltage phase angle of the power grid, the fast phase locking processing method based on phase angle compensation further includes: obtaining the compensation angle according to the d-axis component voltage and the q-axis component voltage by a fourth formula, wherein the fourth formula is: represents the compensation angle, V gdt represents the d-axis component voltage, V gqt represents the q-axis component voltage.

[0019] According to another aspect of an embodiment of the present invention, a fast phase-locking processing device based on phase angle compensation is also provided, including: a first acquisition unit, used to acquire the three-phase voltage of the power grid through a voltage sensor in the power grid; a transformation unit, used to perform coordinate transformation on the three-phase voltage to obtain a d-axis component voltage and a q-axis component voltage; a first processing unit, used to process the q-axis component voltage using a proportional integral PI controller to obtain a frequency deviation; a first superposition unit, used to superimpose the frequency deviation and the rated frequency value to obtain a superposition amount; a second superposition unit, used to integrate the superposition amount and then superimpose it with a compensation angle to obtain a voltage phase angle of the power grid, wherein the compensation angle is obtained based on the d-axis component voltage and the q-axis component voltage; a second processing unit, used to control the current loop of the power grid using the voltage phase angle to perform fast phase-locking processing on the power grid.

[0020] Optionally, the transformation unit includes: a first acquisition module, used to acquire an initial phase angle of the current loop; and a second acquisition module, used to obtain the d-axis component voltage and the q-axis component voltage according to the initial phase angle and the three-phase voltage through a first formula, wherein the first formula is: V ga 、V gband V gc represents the three-phase voltage, θ represents the initial phase angle, V gdt represents the d-axis component voltage, V gqt represents the q-axis component voltage.

[0021] Optionally, the first processing unit includes: a first processing module, configured to process the q-axis component voltage using a proportional-integral (PI) controller through a second formula to obtain the frequency deviation, wherein the second formula is: Δω represents the frequency deviation, V gqt represents the q-axis component voltage, k p represents the proportional coefficient of the PI controller, k i represents the integral coefficient of the PI controller, and s represents the operator in Laplace transform.

[0022] Optionally, the second superposition unit includes: a superposition module, configured to integrate the superposition amount through a third formula and then superimpose the result with the compensation angle to obtain a voltage phase angle of the power grid, wherein the third formula is: θ represents the voltage phase angle, Δω represents the frequency deviation, ω n represents the rated frequency value, and φ represents the compensation angle.

[0023] Optionally, the fast phase-locking processing device based on phase angle compensation further includes: a second acquisition unit, configured to obtain the compensation angle according to the d-axis component voltage and the q-axis component voltage by a fourth formula before performing integration processing on the superposition amount and superimposing it with the compensation angle to obtain the voltage phase angle of the power grid, wherein the fourth formula is: φ represents the compensation angle, V gdt represents the d-axis component voltage, V gqt represents the q-axis component voltage.

[0024] According to another aspect of an embodiment of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium includes a stored program, wherein the program executes any one of the above-mentioned fast phase locking processing methods based on phase angle compensation.

[0025] According to another aspect of an embodiment of the present invention, a processor is further provided, the processor being used to run a program, wherein the program, when running, executes any one of the above-mentioned fast phase locking processing methods based on phase angle compensation.

[0026] According to another aspect of an embodiment of the present invention, a computer program product is provided, comprising computer instructions, wherein when the computer instructions are executed by a processor, any one of the above-mentioned fast phase locking processing methods based on phase angle compensation is executed.

[0027] In the embodiment of the present invention, the three-phase voltage of the power grid is obtained by the voltage sensor in the power grid; the three-phase voltage is transformed into coordinates to obtain the d-axis component voltage and the q-axis component voltage; the q-axis component voltage is processed by the proportional integral PI controller to obtain the frequency deviation; the frequency deviation and the rated frequency value are superimposed to obtain the superposition; the superposition is integrated and then superimposed with the compensation angle to obtain the voltage phase angle of the power grid, wherein the compensation angle is obtained according to the d-axis component voltage and the q-axis component voltage; the voltage phase angle is used to control the current loop of the power grid to perform fast phase-locking processing on the power grid. The above technical solution provided by the present invention realizes the use of the V generated by the abc / dq transformation in the phase-locked loop. gdt and V gqt The value of is used to inversely calculate the phase angle of the phase-locked loop output and the phase angle difference of the grid voltage, and then the phase angle compensation is performed on the phase-locked loop output, thereby accelerating the synchronization speed of the current vector and the voltage vector under conditions such as phase jump, thereby solving the technical problem in the related technology that the grid system may be disconnected from the grid due to the long-term inability to synchronize the inverter current vector and voltage vector when a large-angle phase jump occurs, causing bus overvoltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0029] Figure 1 It is a system block diagram of a root-grid type grid-connected inverter according to the prior art;

[0030] Figure 2 is a simplified block diagram of a grid-following inverter according to an embodiment of the present invention;

[0031] Figure 3 is a system structure diagram of a typical phase-locked loop according to the prior art;

[0032] Figure 4 is the above Figure 3 The equivalent control block diagram of the phase-locked loop;

[0033] Figure 5 It is a voltage and current vector relationship diagram under normal working conditions in the prior art;

[0034] Figure 6 It is a schematic diagram of the voltage and current vector relationship after a grid voltage phase jump fault according to the prior art;

[0035] Figure 7 It is a hardware structure block diagram of a mobile terminal of a fast phase locking processing method based on phase angle compensation according to an embodiment of the present invention;

[0036] Figure 8 is a flow chart of a fast phase locking processing method based on phase angle compensation according to an embodiment of the present invention;

[0037] Fig. 9 is a control block diagram of a phase-locked loop according to an embodiment of the present invention;

[0038] Fig.10 is a schematic diagram of a calculation principle of a feedforward compensation angle φ according to an embodiment of the present invention;

[0039] Fig.11 is a schematic diagram of the effect of phase angle difference on current loop control according to an embodiment of the present invention;

[0040] Fig.12 is a flow chart of an optional fast phase locking processing method based on phase angle compensation according to an embodiment of the present invention;

[0041] Fig.13 is a schematic diagram of verifying a fast phase-locking processing method based on phase angle compensation provided in an embodiment of the present invention;

[0042] Fig.14 is a schematic diagram of a fast phase locking processing device based on phase angle compensation according to an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0044] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0045] As introduced in the background technology, in the related art, the power grid system may be disconnected from the grid due to the long-term inability to synchronize the inverter current vector and voltage vector when the phase jump is large, causing the busbar to be over-voltage. In view of the above defects, in the embodiments of the present invention, a fast phase-locking processing method and device based on phase angle compensation, a computer-readable storage medium, a processor and a computer program product are provided.

[0046] For the convenience of description, some nouns or terms appearing in the embodiments of the present invention are explained below:

[0047] Phase-Locked Loop - A software algorithm module used to determine the phase information of the input signal.

[0048] Grid-following inverter - uses a phase-locked loop to achieve phase setting and controls the inverter into an inverter form that is a controlled current source.

[0049] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0050] The method embodiments provided in the embodiments of the present invention can be executed in a mobile terminal, a computer terminal or a similar computing device. Taking running on a mobile terminal as an example, Figure 7 1 is a hardware structure block diagram of a mobile terminal of a fast phase-locking processing method based on phase angle compensation according to an embodiment of the present invention. Figure 7 As shown, the mobile terminal may include one or more ( Figure 7 Only one is shown in the figure) a processor 702 (the processor 702 may include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA) and a memory 704 for storing data, wherein the mobile terminal may also include a transmission device 706 and an input / output device 708 for communication functions. It can be understood by those skilled in the art that Figure 7 The structure shown is only for illustration and does not limit the structure of the mobile terminal. Figure 7 More or fewer components as shown, or with Figure 7 Different configurations are shown.

[0051] The memory 704 can be used to store computer programs, for example, software programs and modules of application software, such as the computer program corresponding to the fast phase-locking processing method based on phase angle compensation in the embodiment of the present invention. The processor 702 executes various functional applications and data processing by running the computer program stored in the memory 704, that is, the above method is implemented. The memory 704 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 704 may further include a memory remotely arranged relative to the processor 702, and these remote memories can be connected to the mobile terminal via a network. Examples of the above network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof. The transmission device 706 is used to receive or send data via a network. The specific example of the above network may include a wireless network provided by a communication provider of the mobile terminal. In one example, the transmission device 706 includes a network adapter (Network Interface Controller, referred to as NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 706 may be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0052] According to an embodiment of the present invention, a method embodiment of a fast phase-locked processing method based on phase angle compensation is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0053] Figure 8 is a flow chart of a fast phase locking processing method based on phase angle compensation according to an embodiment of the present invention, such as Figure 7 As shown, the fast phase-locking processing method based on phase angle compensation includes the following steps:

[0054] Step S802: acquiring the three-phase voltage of the power grid through a voltage sensor in the power grid.

[0055] In this embodiment, a voltage sensor can be used to obtain the three-phase voltage V in the power grid. ga 、V gb and V gc .

[0056] Fig. 9 is a control block diagram of a phase-locked loop according to an embodiment of the present invention, such as Fig. 9 As shown, V ga 、V gb and V gc Indicates the three-phase grid voltage.

[0057] Step S804, performing coordinate transformation on the three-phase voltage to obtain a d-axis component voltage and a q-axis component voltage.

[0058] In this embodiment, if Fig. 9 As shown, V gdt and V gqt Represents the d and q axis component voltages generated by the grid voltage after abc / dq transformation.

[0059] Step S806: Process the q-axis component voltage using a proportional-integral (PI) controller to obtain a frequency deviation.

[0060] Step S808: superimpose the frequency deviation amount and the rated frequency value to obtain a superimposed amount.

[0061] Step S810, integrating the superposition amount and superimposing it with the compensation angle to obtain the voltage phase angle of the power grid, wherein the compensation angle is obtained according to the d-axis component voltage and the q-axis component voltage.

[0062] Step S812, using the voltage phase angle to control the current loop of the power grid to perform fast phase-locking processing on the power grid.

[0063] As can be seen from the above, in the embodiment of the present invention, the three-phase voltage of the power grid can be obtained by the voltage sensor in the power grid; the three-phase voltage is transformed into coordinates to obtain the d-axis component voltage and the q-axis component voltage; the q-axis component voltage is processed by the proportional integral PI controller to obtain the frequency deviation; the frequency deviation and the rated frequency value are superimposed to obtain the superposition; the superposition is integrated and then superimposed with the compensation angle to obtain the voltage phase angle of the power grid, wherein the compensation angle is obtained according to the d-axis component voltage and the q-axis component voltage; the voltage phase angle is used to control the current loop of the power grid to perform fast phase-locking processing on the power grid, thereby realizing the V generated by the abc / dq transformation in the phase-locked loop. gdt and V gqt The value of is used to inversely calculate the phase angle of the phase-locked loop output and the phase angle difference of the grid voltage, and then the phase angle compensation is performed on the phase-locked loop output, thereby accelerating the synchronization speed of the current vector and the voltage vector under conditions such as phase jump.

[0064] The technical solution provided by the embodiment of the present invention solves the technical problem in the related art that the power grid system may be disconnected from the grid due to bus overvoltage caused by the long-term inability to synchronize the inverter current vector and voltage vector during a large-angle phase jump.

[0065] According to the above embodiment of the present invention, coordinate transformation is performed on the three-phase voltage to obtain the d-axis component voltage and the q-axis component voltage, including: obtaining the initial phase angle of the current loop; and obtaining the d-axis component voltage and the q-axis component voltage according to the initial phase angle and the three-phase voltage by a first formula, wherein the first formula is: V ga 、V gb and V gc represents the three-phase voltage, θ represents the initial phase angle, V gdt Represents the d-axis component voltage, V gqt Represents the q-axis component voltage.

[0066] In this embodiment, the phase angle θ information is combined with the sampled three-phase voltage V ga 、V gb and V gc Information, get V gdt and V gqt The formula for abc / dq conversion is the same as the first formula above.

[0067] According to the above embodiment of the present invention, the q-axis component voltage is processed by a proportional-integral PI controller to obtain a frequency deviation, including: using a second formula, the q-axis component voltage is processed by a proportional-integral PI controller to obtain a frequency deviation, wherein the second formula is: Δω represents the frequency deviation, V gqt represents the q-axis component voltage, k p represents the proportional coefficient of the PI controller, k i represents the integral coefficient of the PI controller, and s represents the operator in the Laplace transform.

[0068] In this embodiment, the calculation formula for the frequency deviation Δω obtained by passing the q-axis component voltage through a PI controller is as shown in the second formula above.

[0069] According to the above embodiment of the present invention, the superposition amount is integrated and then superimposed with the compensation angle to obtain the voltage phase angle of the power grid, including: integrating the superposition amount and then superimposing with the compensation angle through a third formula to obtain the voltage phase angle of the power grid, wherein the third formula is: θ represents the voltage phase angle, Δω represents the frequency deviation, ω n Indicates the rated frequency value, Indicates the compensation angle.

[0070] In this embodiment, the voltage phase angle of the power grid can be obtained by the third formula above.

[0071] It should be noted that, in the embodiment of the present invention, θ in the above first formula represents the initial phase angle, and θ in the third formula represents the voltage phase angle obtained by processing the initial phase angle.

[0072] According to the above embodiment of the present invention, before the superposition amount is integrated and superimposed with the compensation angle to obtain the voltage phase angle of the power grid, the fast phase locking processing method based on phase angle compensation further includes: obtaining the compensation angle according to the d-axis component voltage and the q-axis component voltage by a fourth formula, wherein the fourth formula is: Indicates the compensation angle, V gdt Represents the d-axis component voltage, V gqt Represents the q-axis component voltage.

[0073] In this embodiment, the phase angle of the feedforward compensation is It can be calculated using the fourth formula above.

[0074] Among them, in the embodiment of the present invention, the feedforward compensation angle The calculation principle is as follows: Fig.10 is the feedforward compensation angle according to an embodiment of the present invention The schematic diagram of the computer theory is as follows: Fig.10 As shown, V gd -V gq The coordinate system is the two-phase rotating coordinate system where the grid voltage is located, V gd_θ -V gq_θ The coordinate system is a two-phase rotating coordinate system constructed based on the output of the phase-locked loop. The construction here means that the phase angle θ of the phase-locked loop output is used as Figure 1 The angle values ​​of all abc / dq transformations and dq / abc inverse transformations in the current loop, the current reference value I of the system dref and I qref With V gd_θ -V gq_θ Alignment.

[0075] When phase lock is not completed, V gd -V gq Coordinate System and V gd_θ -V gq_θ The coordinate systems do not completely coincide with each other, and there is a phase angle difference, such as Figure 5 Angle in As shown. The grid voltage is V gd_θ -V gq_θ The components in the coordinate system are: Where θ is the angle value of the phase-locked loop output, θ g is the actual grid voltage phase angle value.

[0076] According to the above formula It can be seen that the regulation of the phase-locked loop will continuously reduce the grid voltage at V gd_θ -V gq_θ The value of the q-axis component on the coordinate system, which causes the phase angle difference φ to decrease continuously until V gd_θ -V gq_θ Coordinate System and V gd -V gq The coordinate systems are completely overlapped and the system phase lock is completed.

[0077] Fig.11 Schematic diagram of the effect of phase angle difference on current loop control according to an embodiment of the present invention. Fig.11 As shown, V gd and V gq Refers to the dq component value of the grid voltage determined based on the true phase angle; V gd_θ and V gd_θ Refers to the dq component value of the grid voltage determined based on the phase angle of the phase-locked loop output, I dqref Refers to the desired current reference value, I dqref_pll The value is the actual current reference value.

[0078] When the inverter adopts the grid-following control architecture, the angle of the current vector reference value can only be given according to the angle of the phase-locked loop output. The phase angle θ output by the phase-locked loop is used as Figure 1 The angle values ​​of all abc / dq transformations and dq / abc inverse transformations in the current loop, the current reference value I of the system dref and I qref With V gd_θ -V gq_θ Alignment.

[0079] Since the current reference given value is affected by the phase angle difference Assume that the direction of the current vector reference value we expect is along V gd direction, such as Fig.11 I dqref As shown, due to the influence of the phase angle difference, the actual current vector reference value direction is along V gd_θ direction, such as Fig.11 I dqref_pll As shown in the figure, the actual output current is inconsistent with the expected one, resulting in output power confusion. In severe cases, the inverter may even be disconnected from the grid due to the protection triggered by the over-high or under-low DC side voltage.

[0080] From the above analysis, it can be seen that the phase angle difference between the phase-locked loop output angle and the real angle of the grid voltage during dynamic regulation is an important factor affecting system performance. In order to eliminate its influence, this patent proposes the following Fig. 9 The improvement plan shown. Fig. 9 As shown, by dynamically compensating the phase angle difference in the phase-locked loop To the angle value of the PLL output, and then the response speed of the phase-locked loop system.

[0081] Due to the phase difference It is not easy to obtain in practice, so here we propose to use the measurable quantity to calculate the value of the phase angle difference φ. As shown, the grid voltage V g In V gd_θ -V gq_θ Projection value V on the coordinate system gdt and V gqt contains angle information, so the phase difference The sine and cosine expressions of are as follows: Combining this formula, the angle φ that needs feedforward compensation can be obtained as:

[0082] It should be noted that, in the embodiment of the present invention, the specific implementation block diagram is as follows Fig.12 ( Fig.12 , which is a flowchart of an optional fast phase-locking processing method based on phase angle compensation according to an embodiment of the present invention, wherein the voltage sensor obtains the three-wire voltage V ga 、V gb and V gc后 , can be combined with the phase angle θ to perform abc / dq transformation to obtain V gdt and V gqt ; V gqt The frequency deviation Δω is obtained through the PI controller; Δω is superimposed on the rated frequency value and then integrated and superimposed on the compensation angle Get the voltage phase angle; finally output the phase angle θ to control the current loop. Here we only need to use the output V of the abc / dq conversion in the phase-locked loop gdt and V gqt The value of the angle output value is according to the formula Just make the corrections.

[0083] use Figure 1 The system structure shown in Figure 1 and the system parameters shown in Table 1 can be used to obtain simulation verification results based on MATLAB / SIMULINK. Fig.13 As shown. Fig.13 ( Fig.13 , which is a schematic diagram for verifying the fast phase-locking processing method based on phase angle compensation provided by an embodiment of the present invention, shows that when a 90° phase jump fault occurs in the grid voltage, the grid-connected inverter needs 61ms under the traditional solution for the current vector to follow the upper voltage vector; while under the proposed improved algorithm, it only takes 4ms for the current vector to follow the upper voltage vector. This fully proves the superiority of the proposed fast phase-locking improvement solution.

[0084] Therefore, the above technical solution provided by the embodiment of the present invention can help the system quickly achieve phase lock under fault conditions such as phase angle jump of the grid voltage, avoiding output power confusion and shutdown due to under / overvoltage on the DC side of the inverter. The verification results show that the system synchronization time provided by the embodiment of the present invention can be reduced from 61ms to 4ms, and the implementation method is simple, only needing to follow the formula A simple modification of the traditional phase-locked loop is sufficient and can be extended to all scenarios where a phase-locked loop is required to achieve synchronization.

[0085] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0086] Through the description of the above implementation methods, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in each embodiment of the present application.

[0087] According to an embodiment of the present invention, a fast phase locking processing device based on phase angle compensation is provided for implementing the fast phase locking processing method based on phase angle compensation. Fig.14 is a schematic diagram of a fast phase locking processing device based on phase angle compensation according to an embodiment of the present invention, such as Fig.14 As shown, the device includes: a first acquisition unit 1401, a transformation unit 1403, a first processing unit 1405, a first superposition unit 1407, a second superposition unit 1409 and a second processing unit 1411. The fast phase locking processing device based on phase angle compensation is described below.

[0088] The first acquisition unit 1401 is used to acquire the three-phase voltage of the power grid through a voltage sensor in the power grid.

[0089] The transformation unit 1403 is used to perform coordinate transformation on the three-phase voltage to obtain a d-axis component voltage and a q-axis component voltage.

[0090] The first processing unit 1405 is used to process the q-axis component voltage by using a proportional-integral (PI) controller to obtain a frequency deviation.

[0091] The first superposition unit 1407 is used to superimpose the frequency deviation amount and the rated frequency value to obtain a superposition amount.

[0092] The second superposition unit 1409 is used to integrate the superposition amount and then superimpose it with the compensation angle to obtain the voltage phase angle of the power grid, wherein the compensation angle is obtained according to the d-axis component voltage and the q-axis component voltage.

[0093] The second processing unit 1411 is used to control the current loop of the power grid by using the voltage phase angle to perform fast phase-locking processing on the power grid.

[0094] It should be noted here that the above-mentioned first acquisition unit 1401, transformation unit 1403, first processing unit 1405, first superposition unit 1407, second superposition unit 1409 and second processing unit 1411 correspond to steps S802 to S812 in the above-mentioned embodiments, and the six units have the same instances and application scenarios implemented by the corresponding steps, but are not limited to the contents disclosed in the above-mentioned embodiments.

[0095] As can be seen from the above, in the scheme recorded in the above-mentioned embodiment of the present invention, the three-phase voltage of the power grid can be obtained by the first acquisition unit through the voltage sensor in the power grid; the three-phase voltage is transformed by the conversion unit to obtain the d-axis component voltage and the q-axis component voltage; the q-axis component voltage is processed by the first processing unit using the proportional integral PI controller to obtain the frequency deviation; the frequency deviation and the rated frequency value are superimposed by the first superposition unit to obtain the superposition amount; the superposition amount is integrated by the second superposition unit and then superimposed with the compensation angle to obtain the voltage phase angle of the power grid, wherein the compensation angle is obtained according to the d-axis component voltage and the q-axis component voltage; the voltage phase angle is used to control the current loop of the power grid by the second processing unit to perform fast phase-locking processing on the power grid, thereby realizing the V generated by the abc / dq transformation in the phase-locked loop. gdt and V gqt The value of is used to inversely calculate the phase angle of the phase-locked loop output and the phase angle difference of the grid voltage, and then the phase angle compensation is performed on the phase-locked loop output, thereby accelerating the synchronization speed of the current vector and the voltage vector under conditions such as phase jump.

[0096] The technical solution provided by the embodiment of the present invention solves the technical problem in the related art that the power grid system may be disconnected from the grid due to bus overvoltage caused by the long-term inability to synchronize the inverter current vector and voltage vector during a large-angle phase jump.

[0097] Optionally, the transformation unit includes: a first acquisition module, used to acquire the initial phase angle of the current loop; a second acquisition module, used to obtain the d-axis component voltage and the q-axis component voltage according to the initial phase angle and the three-phase voltage through a first formula, wherein the first formula is: V ga 、V gb and V gc represents the three-phase voltage, θ represents the initial phase angle, V gdt Represents the d-axis component voltage, V gqt Represents the q-axis component voltage.

[0098] Optionally, the first processing unit includes: a first processing module, used to process the q-axis component voltage using a proportional integral PI controller through a second formula to obtain a frequency deviation, wherein the second formula is: Δω represents the frequency deviation, V gqt represents the q-axis component voltage, k p represents the proportional coefficient of the PI controller, k i represents the integral coefficient of the PI controller, and s represents the operator in the Laplace transform.

[0099] Optionally, the second superposition unit includes: a superposition module, which is used to integrate the superposition amount through a third formula and then superimpose it with the compensation angle to obtain a voltage phase angle of the power grid, wherein the third formula is: θ represents the voltage phase angle, Δω represents the frequency deviation, ω n represents the rated frequency value, and φ represents the compensation angle.

[0100] Optionally, the fast phase lock processing device based on phase angle compensation further includes: a second acquisition unit, which is used to obtain the compensation angle according to the d-axis component voltage and the q-axis component voltage by a fourth formula before superimposing the superposition amount with the compensation angle after integrating the superposition amount to obtain the voltage phase angle of the power grid, wherein the fourth formula is: φ represents the compensation angle, V gdt Represents the d-axis component voltage, V gqt Represents the q-axis component voltage.

[0101] According to another aspect of an embodiment of the present invention, a processor is provided, and the processor is used to run a program, wherein when the program is run, any one of the above-mentioned fast phase locking processing methods based on phase angle compensation is executed.

[0102] According to another aspect of an embodiment of the present invention, a computer program product is provided, comprising computer instructions, which, when executed by a processor, execute any one of the above-mentioned fast phase-locking processing methods based on phase angle compensation.

[0103] According to another aspect of an embodiment of the present invention, a computer-readable storage medium is provided, the computer-readable storage medium comprising a stored program, wherein the program executes any one of the above-mentioned fast phase-locking processing methods based on phase angle compensation.

[0104] Optionally, in this embodiment, the computer-readable storage medium may be located in any one of the computer terminals in a computer terminal group in a computer network, or in any one of the communication devices in a communication device group.

[0105] Optionally, in this embodiment, the computer-readable storage medium is configured to store program codes for executing the following steps: obtaining the three-phase voltage of the power grid through a voltage sensor in the power grid; performing coordinate transformation on the three-phase voltage to obtain a d-axis component voltage and a q-axis component voltage; processing the q-axis component voltage using a proportional-integral (PI) controller to obtain a frequency deviation; superimposing the frequency deviation and the rated frequency value to obtain a superimposed amount; integrating the superimposed amount and superimposing it with a compensation angle to obtain a voltage phase angle of the power grid, wherein the compensation angle is obtained based on the d-axis component voltage and the q-axis component voltage; and controlling the current loop of the power grid using the voltage phase angle to perform fast phase-locking processing on the power grid.

[0106] Optionally, in this embodiment, the computer-readable storage medium is configured to store a program code for executing the following steps: obtaining an initial phase angle of the current loop; obtaining a d-axis component voltage and a q-axis component voltage according to the initial phase angle and the three-phase voltage by a first formula, wherein the first formula is: V ga 、V gb and V gc represents the three-phase voltage, θ represents the initial phase angle, V gdt Represents the d-axis component voltage, V gqt Represents the q-axis component voltage.

[0107] Optionally, in this embodiment, the computer-readable storage medium is configured to store a program code for executing the following steps: using a proportional-integral PI controller to process the q-axis component voltage through a second formula to obtain a frequency deviation, wherein the second formula is: Δω represents the frequency deviation, V gqt represents the q-axis component voltage, k p represents the proportional coefficient of the PI controller, k i represents the integral coefficient of the PI controller, and s represents the operator in the Laplace transform.

[0108] Optionally, in this embodiment, the computer-readable storage medium is configured to store a program code for executing the following steps: integrating the superposition amount and superimposing it with the compensation angle by a third formula to obtain a voltage phase angle of the power grid, wherein the third formula is: θ represents the voltage phase angle, Δω represents the frequency deviation, ω n Indicates the rated frequency value, Indicates the compensation angle.

[0109] Optionally, in this embodiment, the computer-readable storage medium is configured to store a program code for executing the following steps: before integrating the superposition amount and superimposing it with the compensation angle to obtain the voltage phase angle of the power grid, obtaining the compensation angle according to the d-axis component voltage and the q-axis component voltage by a fourth formula, wherein the fourth formula is: Indicates the compensation angle, V gdt Represents the d-axis component voltage, V gqt Represents the q-axis component voltage.

[0110] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0111] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0112] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0113] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0114] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0115] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0116] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A fast phase-locking processing method based on phase angle compensation, characterized in that: include: Obtaining the three-phase voltage of the power grid through a voltage sensor in the power grid; Performing coordinate transformation on the three-phase voltage to obtain a d-axis component voltage and a q-axis component voltage; Processing the q-axis component voltage by using a proportional-integral (PI) controller to obtain a frequency deviation; Superimposing the frequency deviation amount and the rated frequency value to obtain a superimposed amount; Integrating the superposition amount and then superimposing the superposition amount with a compensation angle to obtain a voltage phase angle of the power grid, wherein the compensation angle is obtained according to the d-axis component voltage and the q-axis component voltage; The voltage phase angle is used to control the current loop of the power grid, so as to perform fast phase-locking processing on the power grid.

2. The fast phase locking processing method based on phase angle compensation according to claim 1 is characterized in that: Performing coordinate transformation on the three-phase voltage to obtain a d-axis component voltage and a q-axis component voltage includes: Obtaining an initial phase angle of the current loop; The d-axis component voltage and the q-axis component voltage are obtained according to the initial phase angle and the three-phase voltage through a first formula, wherein the first formula is: V ga 、V gb and V gc represents the three-phase voltage, θ represents the initial phase angle, V gdt represents the d-axis component voltage, V gqt represents the q-axis component voltage.

3. The fast phase locking processing method based on phase angle compensation according to claim 1 is characterized in that: The q-axis component voltage is processed by a proportional-integral PI controller to obtain a frequency deviation, including: The q-axis component voltage is processed by a proportional-integral PI controller through a second formula to obtain the frequency deviation, wherein the second formula is: Δω represents the frequency deviation, V gqt represents the q-axis component voltage, k p represents the proportional coefficient of the PI controller, k i represents the integral coefficient of the PI controller, and s represents the operator in Laplace transform.

4. The fast phase locking processing method based on phase angle compensation according to claim 1 is characterized in that: The superposition amount is integrated and then superimposed with the compensation angle to obtain the voltage phase angle of the power grid, including: The voltage phase angle of the power grid is obtained by integrating the superposition amount and superimposing it with the compensation angle through the third formula, wherein the third formula is: θ represents the voltage phase angle, Δω represents the frequency deviation, ω n Indicates the rated frequency value, represents the compensation angle.

5. The fast phase locking processing method based on phase angle compensation according to claim 1 is characterized in that: Before integrating the superposition amount and superimposing it with the compensation angle to obtain the voltage phase angle of the power grid, the method further includes: The compensation angle is obtained according to the d-axis component voltage and the q-axis component voltage through a fourth formula, wherein the fourth formula is: represents the compensation angle, V gdt represents the d-axis component voltage, V gqt represents the q-axis component voltage.

6. A fast phase-locking processing device based on phase angle compensation, characterized in that: include: A first acquisition unit, configured to acquire a three-phase voltage of the power grid through a voltage sensor in the power grid; A transformation unit, used for performing coordinate transformation on the three-phase voltage to obtain a d-axis component voltage and a q-axis component voltage; A first processing unit is used to process the q-axis component voltage by using a proportional integral PI controller to obtain a frequency deviation; A first superposition unit, used for superimposing the frequency deviation amount and the rated frequency value to obtain a superposition amount; a second superposition unit, configured to integrate the superposition amount and then superpose the integrated amount with a compensation angle to obtain a voltage phase angle of the power grid, wherein the compensation angle is obtained according to the d-axis component voltage and the q-axis component voltage; The second processing unit is used to control the current loop of the power grid by using the voltage phase angle to perform fast phase-locking processing on the power grid.

7. The fast phase-locking processing device based on phase angle compensation according to claim 6, characterized in that: The transformation unit comprises: A first acquisition module, used for acquiring an initial phase angle of the current loop; The second acquisition module is configured to obtain the d-axis component voltage and the q-axis component voltage according to the initial phase angle and the three-phase voltage by using a first formula, wherein the first formula is: V ga 、V gb and V gc represents the three-phase voltage, θ represents the initial phase angle, V gdt represents the d-axis component voltage, V gqt represents the q-axis component voltage.

8. The fast phase-locking processing device based on phase angle compensation according to claim 6, characterized in that: The first processing unit comprises: The first processing module is used to process the q-axis component voltage by using a proportional integral PI controller through a second formula to obtain the frequency deviation, wherein the second formula is: Δω represents the frequency deviation, V gqt represents the q-axis component voltage, k p represents the proportional coefficient of the PI controller, k i represents the integral coefficient of the PI controller, and s represents the operator in Laplace transform.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein the program executes the fast phase locking processing method based on phase angle compensation as described in any one of claims 1 to 5.

10. A computer program product comprising computer instructions, characterized in that: When the computer instructions are executed by the processor, the fast phase locking processing method based on phase angle compensation described in any one of claims 1 to 5 is performed.

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