Phase jump compensation method and device of network-forming converter, terminal and medium

Abstract

The invention provides a phase jump compensation method and device of a network-forming converter, a terminal and a medium. The method comprises the following steps: calculating an instantaneous power angle compensation amount based on the voltage of a grid-connected point of the grid-forming converter; if the instantaneous power angle compensation amount is greater than a preset threshold value, determining a weighted full feed-forward compensation amount based on a capacitor voltage of the network-constructing converter, and determining a cross decoupling compensation amount based on a bridge arm current of the network-constructing converter; and adding the instantaneous power angle compensation amount, the weighted feed-forward compensation amount and the cross decoupling compensation amount into a voltage control loop of the network-forming converter to obtain a control signal added with phase jump compensation. According to the method, the influence of internal virtual inertia on the output response of the grid-forming converter can be reduced, the change of the power grid is quickly responded, the power grid adaptability of the grid-forming converter is improved, the power grid adaptability comprises the phase angle jump adaptability and the power grid strength SCR adaptability, and an overcurrent fault during phase jump is avoided.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and in particular to a phase jump compensation method, device, terminal and medium for a grid-type converter. Background Art

[0002] Grid Forming Converter (GFM) is a new type of power electronic device, mainly used in renewable energy power generation grid-connected systems to improve the stability and reliability of power systems. The main feature of the grid forming converter is that it can independently establish frequency and control voltage, reduce dependence on external voltage sources, and thus improve the stability of the system.

[0003] However, when the grid phase jumps or the system impedance changes, due to the existence of the virtual inertia of the grid-connected converter, the output internal potential of the grid-connected converter cannot quickly track the grid connection point power angle, which makes the converter prone to overcurrent faults. Summary of the invention

[0004] The embodiments of the present invention provide a phase jump compensation method, device, terminal and medium for a grid-type converter to solve the problem that the grid-type converter is prone to overcurrent faults when the grid phase jumps or the system impedance changes.

[0005] In a first aspect, an embodiment of the present invention provides a phase jump compensation method for a grid-connected converter, comprising:

[0006] Calculate the instantaneous power angle compensation based on the voltage at the grid connection point of the grid-connected converter;

[0007] If the instantaneous power angle compensation amount is greater than a preset threshold, a weighted full feedforward compensation amount is determined based on the capacitor voltage of the grid-type converter, and a cross-decoupling compensation amount is determined based on the bridge arm current of the grid-type converter;

[0008] The instantaneous power angle compensation, the weighted feedforward compensation and the cross-decoupling compensation are added to the voltage control loop of the grid-connected converter to obtain a control signal with phase jump compensation.

[0009] In a possible implementation, the formula for calculating the instantaneous power angle compensation based on the voltage at the grid connection point of the grid-connected converter is:

[0010]

[0011] Among them, θ c is the instantaneous power angle compensation, U q1 is the q-axis voltage at the grid connection point, U d1 is the d-axis voltage at the grid connection point, U q0 is the q-axis voltage at the grid-connected point in steady state, U d0 is the d-axis voltage at the grid-connected point in steady state.

[0012] In a possible implementation, the mechanical and electromagnetic models of the grid-type converter are:

[0013]

[0014] Where, ω is the output angular velocity, ω0 is the rated angular velocity, J is the moment of inertia of the synchronous motor, T m is the mechanical torque of the synchronous motor, T e is the electromagnetic torque of the synchronous motor, P e is the instantaneous active power at the grid connection point, D is the damping coefficient, and θ is the output power angle.

[0015] In a possible implementation, the calculation formula of the weighted feedforward compensation is:

[0016] U sd1 =U ref (1-kf)+u sd kf

[0017] U sq1 =u sq kf

[0018] Among them, U sd1 is the weighted feedforward compensation of the d-axis, U ref is the rated voltage, U αβ is the voltage amplitude at the grid connection point, kf is the preset weight, U sd is the d-axis capacitor voltage, U sq1 is the weighted feedforward compensation of the q-axis, U sq is the q-axis capacitor voltage.

[0019] In a possible implementation, before determining the weighted full feedforward compensation amount based on the capacitor voltage of the grid-type converter and determining the cross decoupling compensation amount based on the bridge arm current of the grid-type converter, the method further includes:

[0020] The instantaneous active power at the grid connection point, the instantaneous reactive power at the grid connection point, the voltage amplitude at the grid connection point and the rated voltage are calculated based on the capacitor voltage and bridge arm current of the grid-connected converter; wherein, the formula for calculating the instantaneous active power at the grid connection point, the instantaneous reactive power at the grid connection point, the voltage amplitude at the grid connection point and the rated voltage is:

[0021] P e =1.5×(U sd ×i d +U sq ×i q )

[0022] Q = 1.5 × (U sd ×i q -Usq ×i d )

[0023]

[0024] U ref =(Q ref -Q)*pn+E0

[0025] Among them, P e is the instantaneous active power at the grid connection point, U sd is the d-axis capacitor voltage, U sq is the q-axis capacitor voltage, i d is the d-axis bridge arm current, i q is the q-axis bridge arm current, Q is the instantaneous reactive power at the grid connection point, U αβ is the voltage amplitude at the grid connection point, U α is the α-axis output voltage, U β is the β-axis output voltage, U ref is the rated voltage, Q ref is the rated reactive power, pn is the voltage droop coefficient, and E0 is the no-load amplitude of the virtual internal potential.

[0026] In a possible implementation, the calculation formula of the cross-decoupling compensation amount is:

[0027] U sd 2=i q ωL

[0028] U sq 2=i d ωL

[0029] Among them, U sd2 is the cross decoupling compensation of the d-axis, i q is the q-axis bridge arm current, ω is the output angular velocity, L is the stator inductance of the synchronous motor, U sq2 is the cross-decoupling compensation of the q axis, i d is the d-axis bridge arm current.

[0030] In a possible implementation, the control signal for adding phase jump compensation is:

[0031] θ=∫ωdt+θ c

[0032] U sd =PI(U ref -U αβ )+U sd1 -U sd2

[0033] U sq =U sq1 +U sq2

[0034] Among them, θ is the output power angle, ω is the output angular velocity, θ c is the instantaneous power angle compensation, U sd is the d-axis capacitor voltage, PI is the PI controller, U ref is the rated voltage, U αβ is the voltage amplitude at the grid connection point, U sd1 is the weighted feedforward compensation of the d-axis, U sd2 is the cross decoupling compensation of the d-axis, U sq is the q-axis capacitor voltage, U sq1 is the weighted feedforward compensation of the q-axis, U sq2 is the cross-decoupling compensation of the q-axis.

[0035] In a second aspect, an embodiment of the present invention provides a phase jump compensation device for a grid-type converter, comprising:

[0036] A first calculation module is used to calculate the instantaneous power angle compensation amount based on the voltage of the grid-connected point of the grid-connected converter;

[0037] A second calculation module is used to determine a weighted full feedforward compensation amount based on the capacitor voltage of the grid-type converter and a cross decoupling compensation amount based on the bridge arm current of the grid-type converter when the instantaneous power angle compensation amount is greater than a preset threshold value;

[0038] The jump compensation module is used to add the instantaneous power angle compensation, the weighted feedforward compensation and the cross decoupling compensation to the voltage control loop of the grid-type converter to obtain a control signal with phase jump compensation added.

[0039] In a third aspect, an embodiment of the present invention provides a terminal, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the method described in the first aspect or any possible implementation manner of the first aspect are implemented.

[0040] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method described in the first aspect or any possible implementation method of the first aspect are implemented.

[0041] The embodiments of the present invention provide a phase jump compensation method, device, terminal and medium for a grid-type converter. The phase jump angle is calculated based on the voltage of the grid-connected point of the grid-type converter and used as the instantaneous power angle compensation amount. While performing phase jump compensation based on the instantaneous power angle, the system tracking error is reduced through weighted feedforward compensation to improve the dynamic response effect. The mutual influence between variables is eliminated through cross-decoupling compensation. The influence of the internal virtual inertia on the output response of the grid-type converter can be reduced, the grid change can be responded to quickly, and the grid adaptability of the grid-type converter, including phase angle jump adaptability and grid strength SCR adaptability, is improved to avoid overcurrent faults during phase jumps. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0043] Figure 1 is a flow chart of a phase jump compensation method for a grid-type converter provided by an embodiment of the present invention;

[0044] Figure 2 It is a block diagram of data collection and calculation relationship of a phase jump compensation method of a grid-type converter provided by an embodiment of the present invention;

[0045] Figure 3 is a schematic diagram of the voltage relationship before and after the phase jump provided by an embodiment of the present invention;

[0046] Figure 4 is a calculation block diagram of the rated voltage provided by an embodiment of the present invention;

[0047] Figure 5 is a calculation block diagram of an output power angle provided by an embodiment of the present invention;

[0048] Figure 6 is a calculation block diagram of a driving signal provided by an embodiment of the present invention;

[0049] Figure 7 1 is a schematic structural diagram of a phase jump compensation device for a grid-type converter provided by an embodiment of the present invention;

[0050] Figure 8 is a schematic diagram of a terminal provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0051] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0052] In order to make the purpose, technical solutions and advantages of the present invention more clear, specific embodiments will be described below in conjunction with the accompanying drawings.

[0053] See also Figure 1 , which shows a flow chart of the implementation of the phase jump compensation method of the grid-type converter provided by an embodiment of the present invention, which is described in detail as follows:

[0054] Step 101, calculating an instantaneous power angle compensation amount based on the voltage of the grid-connected point of the grid-connected converter.

[0055] In this embodiment, the data collection and pre-processing process is as follows: Figure 2 As shown in the figure, the collected data includes three-phase output current, three-phase output voltage and three-phase voltage at the grid connection point. First, the grid connection point information is collected through the hardware sampling circuit, and hardware conditioning and filtering and other preliminary signal processing are performed. Then the signal is transformed from the three-phase stationary coordinate system to the two-phase rotating coordinate system to obtain the value i of the bridge arm current in the rotating coordinate system d 、i q ; Get the transformed value U of the AC filter capacitor voltage in the rotating coordinate system sd , U sq , and finally through U sd , U sq 、i d 、i q The instantaneous power at the grid connection point, the voltage amplitude at the grid connection point and the instantaneous power angle of the grid-connected converter are calculated to compensate for phase jumps.

[0056] Step 102: If the instantaneous power angle compensation amount is greater than a preset threshold, a weighted full feedforward compensation amount is determined based on the capacitor voltage of the grid-type converter, and a cross-decoupling compensation amount is determined based on the bridge arm current of the grid-type converter.

[0057] In this embodiment, the instantaneous power angle is calculated in real time based on the rotating coordinate system information of the sampled instantaneous values ​​of voltage and current. When the set instantaneous current change threshold condition is met, that is, the instantaneous power angle is greater than the preset threshold, the output power angle of the synchronous ring of the grid-connected converter is directly compensated.

[0058] The specific calculation method of the compensation amount is as follows: sd , U sqThe instantaneous value is kf-weighted, and the set rated voltage is weighted by (1-kf). The two weighted sums form the voltage full feedforward compensation; the bridge arm current i d 、i q The instantaneous value is used to perform cross-decoupling compensation of the reactor ωL.

[0059] Step 103, adding the instantaneous power angle compensation, the weighted feedforward compensation and the cross decoupling compensation to the voltage control loop of the grid-connected converter to obtain a control signal with phase jump compensation added.

[0060] In this embodiment, based on step 102, the potential power angle compensation in the converter with instantaneous voltage full feedforward and instantaneous current decoupling is obtained, and then the compensation component is directly added to the output of the networked single voltage loop to form a modulation wave, and the modulation wave space vector modulation generates a drive signal.

[0061] In this embodiment, when generating a driving signal, the traditional method of judging sectors and calculating pulse time is not used. Instead, SVPWM based on triple zero-sequence component injection is adopted, and the modulation wave is directly injected into the mean zero-sequence component to achieve it. Finally, the IGBT driving signal is obtained through modulation.

[0062] The embodiment of the present invention calculates the phase jump angle based on the voltage of the grid-connected point of the grid-type converter and uses it as the instantaneous power angle compensation amount. While performing phase jump compensation based on the instantaneous power angle, it reduces the system tracking error through weighted feedforward compensation and improves the dynamic response effect. It eliminates the mutual influence between variables through cross-decoupling compensation, thereby reducing the influence of the internal virtual inertia on the output response of the grid-type converter, responding quickly to grid changes, and improving the grid adaptability of the grid-type converter, including phase angle jump adaptability and grid strength SCR adaptability, to avoid overcurrent faults during phase jumps.

[0063] In a possible implementation, the formula for calculating the instantaneous power angle compensation based on the voltage at the grid connection point of the grid-connected converter is:

[0064]

[0065] Among them, θ c is the instantaneous power angle compensation, U q1 is the q-axis voltage at the grid connection point, U d1 is the d-axis voltage at the grid connection point, U q0 is the q-axis voltage at the grid-connected point in steady state, U d0 is the d-axis voltage at the grid-connected point in steady state.

[0066] In this embodiment, the voltage relationship of the grid connection point before and after the phase jump is as follows: Figure 3As shown, the voltage vector of the PCC grid connection point in steady state is U0, and the current power angle is α; the voltage vector after the phase jump β is U1, and the power angle is α+β. At the moment of phase jump, the internal potential of the converter VSG mode output remains unchanged, and the phase jump β value can be calculated by the following formula:

[0067]

[0068] The above two formulas can be combined to calculate the phase jump angle value β, that is, the instantaneous power angle θ that needs to be compensated c .

[0069] In a possible implementation, the mechanical and electromagnetic models of the grid-type converter are:

[0070]

[0071] Where, ω is the output angular velocity, ω0 is the rated angular velocity, J is the moment of inertia of the synchronous motor, T m is the mechanical torque of the synchronous motor, T e is the electromagnetic torque of the synchronous motor, P e is the instantaneous active power at the grid connection point, D is the damping coefficient, and θ is the output power angle.

[0072] In this embodiment, the grid-type converter adopts a converter control technology that can truly equal the inertia and damping characteristics of a conventional synchronous motor. By simulating the synchronous generator body model, active frequency regulation and reactive voltage regulation, the converter is comparable to the synchronous generator in terms of operating mechanism and external characteristics. The mechanical model and electromagnetic model of the grid-type converter simulating the synchronous generator can be expressed as:

[0073]

[0074] In a possible implementation, the calculation formula of the weighted feedforward compensation is:

[0075] U sd1 =U ref (1-kf)+u sd kf

[0076] U sq1 =u sq k

[0077] Among them, U sd1 is the weighted feedforward compensation of the d-axis, U ref is the rated voltage, U αβ is the voltage amplitude at the grid connection point, kf is the preset weight, U sd is the d-axis capacitor voltage, U sq1 is the weighted feedforward compensation of the q-axis, Usq is the q-axis capacitor voltage.

[0078] In this embodiment, the weighted feedforward compensation amount is determined based on the capacitor voltage and the rated voltage, and the weight kf can be set according to actual conditions. Additional compensation paths and weight factors are introduced into the voltage control loop to reduce the impact of grid voltage fluctuations on the loop output, thereby improving the control system's ability to resist disturbances, thereby improving the performance of the entire control loop.

[0079] In a possible implementation, before determining the weighted full feedforward compensation amount based on the capacitor voltage of the grid-type converter and determining the cross decoupling compensation amount based on the bridge arm current of the grid-type converter, the method further includes:

[0080] The instantaneous active power at the grid connection point, the instantaneous reactive power at the grid connection point, the voltage amplitude at the grid connection point and the rated voltage are calculated based on the capacitor voltage and bridge arm current of the grid-connected converter; wherein, the formula for calculating the instantaneous active power at the grid connection point, the instantaneous reactive power at the grid connection point, the voltage amplitude at the grid connection point and the rated voltage is:

[0081] P e =1.5×(U sd ×i d +U sq ×i q )

[0082] Q = 1.5 × (U sd ×i q -U sq ×i d )

[0083]

[0084] U ref =(Q ref -Q)*pn+E0

[0085] Among them, P e is the instantaneous active power at the grid connection point, U sd is the d-axis capacitor voltage, U sq is the q-axis capacitor voltage, i d is the d-axis bridge arm current, i q is the q-axis bridge arm current, Q is the instantaneous reactive power at the grid connection point, U αβ is the voltage amplitude at the grid connection point, U α is the α-axis output voltage, U β is the β-axis output voltage, U ref is the rated voltage, Q ref is the rated reactive power, pn is the voltage droop coefficient, and E0 is the no-load amplitude of the virtual internal potential.

[0086] In this embodiment, the d-axis voltage and current are multiplied to obtain the active power component on the d-axis, and the q-axis voltage and current are multiplied to obtain the active power component on the q-axis. The two are then added to obtain the total instantaneous active power.

[0087] Multiply the q-axis voltage and the d-axis current to obtain the reactive power component on the q-axis, multiply the d-axis voltage and the q-axis current to obtain the reactive power component on the d-axis, and then subtract the reactive power component on the d-axis from the reactive power component on the q-axis to obtain the total instantaneous reactive power.

[0088] The square root of the sum of the squares of the α-axis output voltage and the β-axis output voltage is the grid-connected point voltage amplitude.

[0089] The rated voltage is used for grid pre-synchronization and voltage droop equation, voltage set value, and grid voltage amplitude. The calculation block diagram is as follows: Figure 4 As shown in Figure 1, the difference between the actual reactive power and the rated reactive power is multiplied by the voltage droop coefficient and the virtual internal potential no-load amplitude is added. The reactive power of the power system can be adjusted by the rated voltage, thereby controlling the voltage level of the converter and the grid connection point.

[0090] In a possible implementation, the calculation formula of the cross-decoupling compensation amount is:

[0091] U sd2 =i q ωL

[0092] U sq2 =i d ωL

[0093] Among them, U sd2 is the cross decoupling compensation of the d-axis, i q is the q-axis bridge arm current, ω is the output angular velocity, L is the stator inductance of the synchronous motor, U sq2 is the cross-decoupling compensation of the q axis, i d is the d-axis bridge arm current.

[0094] In this embodiment, the cross-decoupling compensation amount of the d-axis voltage is calculated based on the q-axis bridge arm current, and the cross-decoupling compensation amount of the q-axis voltage is calculated based on the d-axis bridge arm current, and combined with the stator inductance, so as to eliminate the influence of the q-axis current on the d-axis voltage, and the influence of the d-axis current on the q-axis voltage.

[0095] In a possible implementation, the control signal for adding phase jump compensation is:

[0096] θ=∫ωdt+θ c

[0097] U sd =PI(U ref -Uα β)+U sd1 -U sd2

[0098] U sq =U sq1 +U sq2

[0099] Among them, θ is the output power angle, ω is the output angular velocity, θ c is the instantaneous power angle compensation, U sd is the d-axis capacitor voltage, PI is the PI controller, U ref is the rated voltage, U αβ is the voltage amplitude at the grid connection point, U sd1 is the weighted feedforward compensation of the d-axis, U sd2 is the cross decoupling compensation of the d-axis, U sq is the q-axis capacitor voltage, U sq1 is the weighted feedforward compensation of the q-axis, U sq2 is the cross-decoupling compensation of the q-axis.

[0100] In this embodiment, if Figure 5 As shown in Figure 2, before the phase jump occurs, the output power angle of the converter is calculated only by the output angular velocity, where P ref is the active power command, pm is the active power adjustment coefficient, P e is the active power of the synchronous motor, D is the damping coefficient, and J is the moment of inertia of the synchronous motor. When a phase jump occurs, the instantaneous power angle compensation value θ is calculated based on c Compensate the output power angle.

[0101] like Figure 6 As shown, based on the weight kf, rated voltage U ref , d-axis capacitor voltage U sd And the q-axis bridge arm current i q The output of the PI controller is compensated to obtain the compensated d-axis capacitor voltage U sd , and based on the weight kf, q-axis capacitor voltage U sq And the d-axis bridge arm current i d The compensated q-axis capacitor voltage U is obtained sq , and finally to U sd and U sq Coordinate transformation is performed to obtain three-phase voltage, and SVPWM modulation is performed to generate a drive signal, which is input into the converter PCS for control to achieve phase jump compensation.

[0102] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0103] The following is an embodiment of the device of the present invention. For details not described in detail, reference may be made to the corresponding method embodiments described above.

[0104] Figure 7 The structure diagram of the phase jump compensation device of the grid-type converter provided by the embodiment of the present invention is shown. For the convenience of description, only the part related to the embodiment of the present invention is shown, which is described in detail as follows:

[0105] like Figure 7 As shown, the phase jump compensation device 7 of the grid-type converter includes:

[0106] A first calculation module 71, used for calculating the instantaneous power angle compensation amount based on the voltage of the grid-connected point of the grid-connected converter;

[0107] A second calculation module 72 is used to determine a weighted full feedforward compensation amount based on the capacitor voltage of the grid-type converter and a cross decoupling compensation amount based on the bridge arm current of the grid-type converter when the instantaneous power angle compensation amount is greater than a preset threshold value;

[0108] The jump compensation module 73 is used to add the instantaneous power angle compensation, the weighted feedforward compensation and the cross decoupling compensation to the voltage control loop of the grid-connected converter to obtain a control signal with phase jump compensation added.

[0109] In a possible implementation, the formula for calculating the instantaneous power angle compensation based on the voltage at the grid connection point of the grid-connected converter is:

[0110]

[0111] Among them, θ c is the instantaneous power angle compensation, U q1 is the q-axis voltage at the grid connection point, U d1 is the d-axis voltage at the grid connection point, U q0 is the q-axis voltage at the grid-connected point in steady state, U d0 is the d-axis voltage at the grid-connected point in steady state.

[0112] In a possible implementation, the mechanical and electromagnetic models of the grid-type converter are:

[0113]

[0114] Where, ω is the output angular velocity, ω0 is the rated angular velocity, J is the moment of inertia of the synchronous motor, T m is the mechanical torque of the synchronous motor, T e is the electromagnetic torque of the synchronous motor, P e is the instantaneous active power at the grid connection point, D is the damping coefficient, and θ is the output power angle.

[0115] In a possible implementation, the calculation formula of the weighted feedforward compensation is:

[0116] U sd1 =U ref (1-kf)+u sd kf

[0117] U sq1 =u sq kf

[0118] Among them, U sd1 is the weighted feedforward compensation of the d-axis, U ref is the rated voltage, U αβ is the voltage amplitude at the grid connection point, kf is the preset weight, U sd is the d-axis capacitor voltage, U sq1 is the weighted feedforward compensation of the q-axis, U sq is the q-axis capacitor voltage.

[0119] In a possible implementation, the second calculation module 72 is further configured to:

[0120] Before determining the weighted full feedforward compensation amount based on the capacitor voltage of the grid-type converter and determining the cross decoupling compensation amount based on the bridge arm current of the grid-type converter, the instantaneous active power at the grid-connected point, the instantaneous reactive power at the grid-connected point, the voltage amplitude at the grid-connected point and the rated voltage are calculated based on the capacitor voltage and the bridge arm current of the grid-type converter; wherein the formula for calculating the instantaneous active power at the grid-connected point, the instantaneous reactive power at the grid-connected point, the voltage amplitude at the grid-connected point and the rated voltage is:

[0121] P e =1.5×(U sd ×i d +U sq ×i q )

[0122] Q = 1.5 × (U sd ×i q -U sq ×i d )

[0123]

[0124] U ref =(Q ref -Q)*pn+E0

[0125] Among them, P e is the instantaneous active power at the grid connection point, U sd is the d-axis capacitor voltage, U sq is the q-axis capacitor voltage, i dis the d-axis bridge arm current, i q is the q-axis bridge arm current, Q is the instantaneous reactive power at the grid connection point, U αβ is the voltage amplitude at the grid connection point, U α is the α-axis output voltage, U β is the β-axis output voltage, U ref is the rated voltage, Q ref is the rated reactive power, pn is the voltage droop coefficient, and E0 is the no-load amplitude of the virtual internal potential.

[0126] In a possible implementation, the calculation formula of the cross-decoupling compensation amount is:

[0127] U sd2 =i q ωL

[0128] U sq2 =i d ωL

[0129] Among them, U sd2 is the cross decoupling compensation of the d-axis, i q is the q-axis bridge arm current, ω is the output angular velocity, L is the stator inductance of the synchronous motor, U sq2 is the cross-decoupling compensation of the q axis, i d is the d-axis bridge arm current.

[0130] In a possible implementation, the control signal for adding phase jump compensation is:

[0131] θ=∫ωdt+θ c

[0132] U sd =PI(U ref -U αβ )+U sd1 -U sd2

[0133] U sq =U sq1 +U sq2

[0134] Among them, θ is the output power angle, ω is the output angular velocity, θ c is the instantaneous power angle compensation, U sd is the d-axis capacitor voltage, PI is the PI controller, U ref is the rated voltage, U αβ is the voltage amplitude at the grid connection point, U sd1 is the weighted feedforward compensation of the d-axis, U sd2 is the cross decoupling compensation of the d-axis, U sq is the q-axis capacitor voltage, U sq1 is the weighted feedforward compensation of the q-axis, Usq2 is the cross-decoupling compensation of the q-axis.

[0135] The embodiment of the present invention calculates the phase jump angle based on the voltage of the grid-connected point of the grid-type converter and uses it as the instantaneous power angle compensation amount. While performing phase jump compensation based on the instantaneous power angle, it reduces the system tracking error through weighted feedforward compensation and improves the dynamic response effect. It eliminates the mutual influence between variables through cross-decoupling compensation, thereby reducing the influence of the internal virtual inertia on the output response of the grid-type converter, responding quickly to grid changes, and improving the grid adaptability of the grid-type converter, including phase angle jump adaptability and grid strength SCR adaptability, to avoid overcurrent faults during phase jumps.

[0136] Figure 8 is a schematic diagram of a terminal provided by an embodiment of the present invention. Figure 8 As shown, the terminal 8 of this embodiment includes: a processor 80, a memory 81, and a computer program 82 stored in the memory 81 and executable on the processor 80. When the processor 80 executes the computer program 82, the steps in the above-mentioned embodiments of the phase jump compensation method for the grid-type converter are implemented, for example Figure 1 Alternatively, when the processor 80 executes the computer program 82, the functions of each module / unit in the above-mentioned device embodiments are realized, for example, Figure 7 Functions of modules / units 71 to 73 are shown.

[0137] Exemplarily, the computer program 82 may be divided into one or more modules / units, which are stored in the memory 81 and executed by the processor 80 to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of implementing specific functions, which are used to describe the execution process of the computer program 82 in the terminal 8. For example, the computer program 82 may be divided into Figure 7 Modules / units 71 to 73 are shown.

[0138] The terminal 8 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The terminal 8 may include, but is not limited to, a processor 80 and a memory 81. Those skilled in the art will appreciate that Figure 8 It is only an example of terminal 8 and does not constitute a limitation on terminal 8. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the terminal may also include input and output devices, network access devices, buses, etc.

[0139] The processor 80 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0140] The memory 81 may be an internal storage unit of the terminal 8, such as a hard disk or memory of the terminal 8. The memory 81 may also be an external storage device of the terminal 8, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the terminal 8. Further, the memory 81 may also include both an internal storage unit of the terminal 8 and an external storage device. The memory 81 is used to store the computer program and other programs and data required by the terminal. The memory 81 may also be used to temporarily store data that has been output or is to be output.

[0141] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0142] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0143] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0144] In the embodiments provided by the present invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as 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 devices or units, which can be electrical, mechanical or other forms.

[0145] 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 network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0146] 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.

[0147] If the integrated module / 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 present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of the above-mentioned phase jump compensation method embodiments of each grid-type converter can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device that can carry the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practices in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practices, computer-readable media does not include electrical carrier signals and telecommunication signals.

[0148] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A phase jump compensation method for a grid-connected converter, characterized in that: include: Calculate the instantaneous power angle compensation based on the voltage at the grid connection point of the grid-connected converter; If the instantaneous power angle compensation amount is greater than a preset threshold, a weighted full feedforward compensation amount is determined based on the capacitor voltage of the grid-type converter, and a cross-decoupling compensation amount is determined based on the bridge arm current of the grid-type converter; The instantaneous power angle compensation amount, the weighted feedforward compensation amount and the cross-decoupling compensation amount are added to the voltage control loop of the grid-connected converter to obtain a control signal with phase jump compensation added.

2. The phase jump compensation method of the grid-type converter according to claim 1, characterized in that: The formula for calculating the instantaneous power angle compensation based on the voltage at the grid-connected point of the grid-connected converter is: Among them, θ c is the instantaneous power angle compensation, U q1 is the q-axis voltage at the grid connection point, U d1 is the d-axis voltage at the grid connection point, U q0 is the q-axis voltage at the grid-connected point in steady state, U d0 is the d-axis voltage at the grid-connected point in steady state.

3. The phase jump compensation method of the grid-connected converter according to claim 1, characterized in that: The mechanical and electromagnetic models of the grid-type converter are: Where, ω is the output angular velocity, ω0 is the rated angular velocity, J is the moment of inertia of the synchronous motor, T m is the mechanical torque of the synchronous motor, T e is the electromagnetic torque of the synchronous motor, P e is the instantaneous active power at the grid connection point, D is the damping coefficient, and θ is the output power angle.

4. The phase jump compensation method of the grid-connected converter according to claim 1, characterized in that: The calculation formula of weighted feedforward compensation is: YOU sd1 =You ref (1-kf)+u sd kf YOU sq1 =u sq kf Among them, U sd1 is the weighted feedforward compensation of the d-axis, U ref is the rated voltage, U αβ is the voltage amplitude at the grid connection point, kf is the preset weight, U sd is the d-axis capacitor voltage, U sq1 is the weighted feedforward compensation of the q-axis, U sq is the q-axis capacitor voltage.

5. The phase jump compensation method of the grid-type converter according to claim 4, characterized in that: Before determining the weighted full feedforward compensation amount based on the capacitor voltage of the grid-type converter and determining the cross decoupling compensation amount based on the bridge arm current of the grid-type converter, the method further includes: The instantaneous active power at the grid connection point, the instantaneous reactive power at the grid connection point, the voltage amplitude at the grid connection point and the rated voltage are calculated based on the capacitor voltage and the bridge arm current of the grid-connected converter; wherein the formula for calculating the instantaneous active power at the grid connection point, the instantaneous reactive power at the grid connection point, the voltage amplitude at the grid connection point and the rated voltage is: P e =1.5×(U sd ×and d +U sq ×and q ) Q=1.5×(U sd ×i q -U sq ×i d ) U ref =(Q ref -Q)*pm+E0 Among them, P e is the instantaneous active power at the grid connection point, U sd is the d-axis capacitor voltage, U sq is the q-axis capacitor voltage, i d is the d-axis bridge arm current, i q is the q-axis bridge arm current, Q is the instantaneous reactive power at the grid connection point, U αβ is the voltage amplitude at the grid connection point, U α is the α-axis output voltage, U β is the β-axis output voltage, U ref is the rated voltage, Q ref is the rated reactive power, pn is the voltage droop coefficient, and E0 is the no-load amplitude of the virtual internal potential.

6. The phase jump compensation method of a grid-connected converter according to claim 1, characterized in that: The calculation formula of cross decoupling compensation is: U sd2 =i q ωL U sq2 =i d ωL Among them, U sd2 is the cross decoupling compensation of the d-axis, i q is the q-axis bridge arm current, ω is the output angular velocity, L is the stator inductance of the synchronous motor, U sq2 is the cross-decoupling compensation of the q axis, i d is the d-axis bridge arm current.

7. The phase jump compensation method of a grid-connected converter according to claim 1, characterized in that: The control signal with phase jump compensation is: θ=∫ωdt+θ c IN sd =PI(U ref -IN αβ )+U sd1 -IN sd2 IN sq =U sq1 +U sq2 Among them, θ is the output power angle, ω is the output angular velocity, θ c is the instantaneous power angle compensation, U sd is the d-axis capacitor voltage, PI is the PI controller, U ref is the rated voltage, U αβ is the voltage amplitude at the grid connection point, U sd1 is the weighted feedforward compensation of the d-axis, U sd2 is the cross decoupling compensation of the d-axis, U sq is the q-axis capacitor voltage, U sq1 is the weighted feedforward compensation of the q-axis, U sq2 is the cross-decoupling compensation of the q-axis.

8. A phase jump compensation device for a grid-type converter, characterized in that: include: A first calculation module is used to calculate the instantaneous power angle compensation amount based on the voltage of the grid-connected point of the grid-connected converter; A second calculation module is used to determine a weighted full feedforward compensation amount based on the capacitor voltage of the grid-type converter and a cross decoupling compensation amount based on the bridge arm current of the grid-type converter when the instantaneous power angle compensation amount is greater than a preset threshold; The jump compensation module is used to add the instantaneous power angle compensation, the weighted feedforward compensation and the cross decoupling compensation to the voltage control loop of the grid-connected converter to obtain a control signal with phase jump compensation added.

9. A terminal comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method as claimed in any one of claims 1 to 7 are implemented.

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