New energy power generation system and converter control method and converter controller thereof

Abstract

The invention provides a new energy power generation system, a converter control method thereof and a converter controller. The converter control method comprises the following steps: inputting a last received three-phase voltage value of a station grid-connected point into a phase-locked loop to obtain a phase-locked angle, and determining a reference phase angle based on the phase-locked angle; based on the reference phase angle, carrying out coordinate transformation on the grid-side inductive current value of the converter, which is collected most recently, to obtain a dq-axis positive and negative sequence inductive current value, and carrying out coordinate transformation on the grid-side three-phase voltage value of the converter, which is collected most recently, to obtain a dq-axis positive and negative sequence grid-side voltage value; based on the dq-axis positive and negative sequence inductance current value and the dq-axis positive and negative sequence network side voltage value, determining a dq-axis network side voltage reference value; and generating a PWM signal for controlling a grid-side three-phase power module of the converter based on the dq-axis grid-side voltage reference value and the reference phase angle.

Description

Technical Field

[0001] The present disclosure generally relates to the field of renewable energy power generation technology, and more specifically, to a renewable energy power generation system and a converter control method and a converter controller thereof. Background Art

[0002] The priority direction of technical research and development is to build a new power system with new energy as the main body, increase the proportion of new energy and the power grid's absorption capacity, and ensure the safe and stable operation of the power grid. In recent years, the new energy industry represented by wind power has maintained a rapid growth trend, but at the same time, the wind power industry still has many technical problems that need to be solved and improved, the first of which is the grid connection stability problem.

[0003] At present, the operation of wind farms at home and abroad adopts the idea of ​​"centralized dispatching and decentralized control". The so-called centralized dispatching means that the wind turbines (hereinafter referred to as wind turbines) in the station are uniformly distributed by the upper-level centralized control center; decentralized control is reflected in the use of an independent control unit for each wind turbine to realize data collection and grid connection / offline control. Each wind turbine is equivalent to an independent individual. In this way, under special working conditions such as low voltage ride-through and high voltage ride-through, the wind turbines disturb each other, the combined effect is weak, and the fault ride-through ability is average. Especially under weak power grid conditions, the wind turbines face the risk of being off-grid. Summary of the invention

[0004] An exemplary embodiment of the present disclosure provides a new energy power generation system and a converter control method and a converter controller thereof, which can effectively solve the stability problem of the grid-connected operation of the new energy power generation system.

[0005] According to a first aspect of an embodiment of the present disclosure, a converter control method for a new energy power generation system is provided, the converter control method comprising: inputting the most recently received three-phase voltage value at the station grid-connected point into a phase-locked loop to obtain a phase-locked angle, and determining a reference phase angle based on the phase-locked angle; based on the reference phase angle, performing a coordinate transformation on the most recently collected grid-side inductor current value of the converter to obtain a dq-axis positive and negative-sequence inductor current value, and performing a coordinate transformation on the most recently collected grid-side three-phase voltage value of the converter to obtain a dq-axis positive and negative-sequence grid-side voltage value; determining a dq-axis grid-side voltage reference value based on the dq-axis positive and negative-sequence inductor current value and the dq-axis positive and negative-sequence grid-side voltage value; and generating a PWM signal for controlling a grid-side three-phase power module of the converter based on the dq-axis positive and negative-sequence inductor current value and the dq-axis positive and negative-sequence grid-side voltage value.

[0006] Optionally, the data collection time point of the converter is the same as that of the station grid-connected point; wherein, the step of determining the reference phase angle based on the phase-locked angle includes: based on the transmission delay of the three-phase voltage value of the station grid-connected point and the phase difference between the high and low voltage sides of the transformer, compensating the phase-locked angle to obtain the reference phase angle; wherein, the converter is connected to the station grid-connected point via the transformer; wherein, the transmission delay is the transmission delay of the three-phase voltage value of the station grid-connected point from the station grid-connected point to the converter.

[0007] Optionally, based on the transmission delay of the three-phase voltage value of the station grid connection point and the phase difference between the high and low voltage sides of the transformer, the phase-locked angle is compensated, and the step of obtaining the reference phase angle includes: taking the sum of the phase-locked angle, the first compensation angle for compensating for the phase difference between the high and low voltage sides, and the second compensation angle for compensating for the transmission delay as the reference phase angle.

[0008] Optionally, the data synchronization collection period of the converter and the station grid-connected point is the same as the control period of the converter, and the switching period of the grid-side three-phase power module is twice the control period; and / or the transmission delay is less than 1ms.

[0009] Optionally, a system short-circuit capacity ratio SCR of a power grid to which the new energy power generation system is connected via the station grid connection point is within a predetermined range.

[0010] Optionally, the step of determining the dq axis grid-side voltage reference value based on the dq axis positive and negative sequence inductor current values ​​and the dq axis positive and negative sequence grid-side voltage values ​​includes: determining the d axis inductor current reference value based on the DC voltage target setting value of the converter, the most recently collected DC voltage value, and the q axis positive sequence grid-side voltage value; determining the q axis inductor current reference value based on the target setting value of the grid-side line voltage effective value of the converter, the most recently collected grid-side line voltage effective value, the most recently collected reactive power value of the converter, and the d axis positive sequence grid-side voltage value; determining the dq axis grid-side voltage reference value based on the d axis inductor current reference value, the q axis inductor current reference value, the dq axis positive and negative sequence inductor current values, and the dq axis positive and negative sequence grid-side voltage values.

[0011] Optionally, the step of determining the dq axis grid-side voltage reference value based on the d-axis inductor current reference value, the q-axis inductor current reference value, the dq axis positive-sequence inductor current value, and the dq axis positive-sequence grid-side voltage value includes: determining the d-axis positive-sequence grid-side voltage reference value based on the d-axis inductor current reference value, the dq axis positive-sequence inductor current value, and the d-axis positive-sequence grid-side voltage value; determining the q-axis positive-sequence grid-side voltage reference value based on the q-axis inductor current reference value, the dq axis positive-sequence inductor current value, and the q-axis positive-sequence grid-side voltage value; determining the d-axis negative-sequence grid-side voltage reference value based on the dq axis negative-sequence inductor current value and the d-axis negative-sequence grid-side voltage value; determining the q-axis negative-sequence grid-side voltage reference value based on the dq axis negative-sequence inductor current value and the q-axis negative-sequence grid-side voltage value; determining the dq axis grid-side voltage reference value based on the d-axis positive-sequence grid-side voltage reference value and the q-axis positive-sequence grid-side voltage reference value.

[0012] According to a second aspect of an embodiment of the present disclosure, a computer-readable storage medium storing a computer program is provided. When the computer program is executed by a processor, the processor is prompted to execute the converter control method of the new energy power generation system as described above.

[0013] According to the third aspect of an embodiment of the present disclosure, a converter controller for a renewable energy power generation system is provided, the converter controller comprising: a processor; and a memory storing a computer program, wherein when the computer program is executed by the processor, the processor is prompted to execute the converter control method for the renewable energy power generation system as described above.

[0014] According to a fourth aspect of an embodiment of the present disclosure, a new energy power generation system is provided, wherein the new energy power generation system includes a converter and the converter controller as described above.

[0015] According to the new energy power generation system and its converter control method and converter controller of the exemplary embodiment of the present invention, the voltage of the substation grid-connected point is introduced into the grid-side control of the converter of the new energy power generation system, and the flexible grid-connected characteristics of the converter are utilized to coordinate and intensively control the decentralized new energy power generation system, so that the new energy power generation system group (for example, a wind turbine group) has the dynamic properties of synchronous control, synchronous response, and synchronous execution, so as to maximize the group effect and synergy of the new energy power generation system, thereby improving the fault ride-through capability and grid-connected stability of the new energy power generation system.

[0016] In the following description, some aspects and / or advantages of the general inventive concept will be set forth, and some other aspects and / or advantages will be known through the following description or the implementation of the general inventive concept. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] These and / or other aspects and advantages of the present application will become clearer and easier to understand from the following detailed description of the embodiments of the present application in conjunction with the accompanying drawings, in which:

[0018] Figure 1 A flowchart showing a converter control method of a new energy power generation system according to an exemplary embodiment of the present disclosure;

[0019] Figure 2 A schematic diagram showing a topological structure of a wind turbine converter according to an exemplary embodiment of the present disclosure is shown;

[0020] Figure 3 A timing diagram showing local control of a station grid connection point and a converter according to an exemplary embodiment of the present disclosure is shown;

[0021] Figure 4 A schematic diagram of coordinate transformation according to an exemplary embodiment of the present disclosure is shown;

[0022] Figure 5 A flow chart showing a method for determining a dq axis grid side voltage reference value based on dq axis positive and negative sequence inductor current values ​​and dq axis positive and negative sequence grid side voltage values ​​according to an exemplary embodiment of the present disclosure;

[0023] Figure 6 A flow chart showing a method for determining a dq axis grid side voltage reference value according to an exemplary embodiment of the present disclosure;

[0024] Figure 7 A schematic diagram showing a voltage outer loop according to an exemplary embodiment of the present disclosure;

[0025] Figure 8 A schematic diagram showing a reactive closed loop according to an exemplary embodiment of the present disclosure;

[0026] Fig. 9 A schematic diagram showing an inner current loop according to an exemplary embodiment of the present disclosure;

[0027] Fig.10 A schematic diagram of low voltage ride through simulation according to an exemplary embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0028] Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like parts throughout. The embodiments will be described below with reference to the drawings in order to explain the present disclosure.

[0029] It should be noted that the terms "first", "second", etc. in the specification and claims of the present disclosure 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 disclosure described herein can be implemented in an order other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0030] It should be noted that the phrase "at least one of the items" in the present disclosure includes three types of parallel situations: "any one of the items", "a combination of any number of the items", and "all of the items". For example, "including at least one of A and B" includes the following three parallel situations: (1) including A; (2) including B; (3) including A and B. Another example is "executing at least one of step 1 and step 2" which means the following three parallel situations: (1) executing step 1; (2) executing step 2; (3) executing step 1 and step 2.

[0031] Figure 1 A flow chart showing a converter control method of a new energy power generation system according to an exemplary embodiment of the present disclosure.

[0032] As an example, the type of the renewable energy power generation system may include, but is not limited to: a wind turbine and / or a photovoltaic power generation system. It should be understood that the type of the renewable energy power generation system may also be other types, and the present disclosure does not limit this. In other words, the application scenario of the converter control method of the renewable energy power generation system according to the exemplary embodiment of the present disclosure is not limited to wind farms, but may also be applied to other types of renewable energy stations.

[0033] Taking the renewable energy power generation system as a wind turbine generator set and the wind power converter as a back-to-back dual PWM converter as an example, the topological structure of the wind power converter can be as follows: Figure 2 As shown, the wind power converter may include a grid-side inverter and a machine-side rectifier, the DC side of the grid-side inverter is connected to the generator of the wind turbine generator set via the machine-side rectifier, the AC side of the grid-side inverter is connected to the low-voltage side of the transformer via a filter (i.e., a grid-side filter), and the high-voltage side of the transformer is connected to the PCC point of the station substation (i.e., the public grid connection point after all the converter equipment in the station is collected). For example, the grid-side filter may be an LC filter or an LCL filter.

[0034] As an example, the converter control method of the new energy power generation system according to the exemplary embodiment of the present disclosure may be executed by a controller of the converter of the new energy power generation system (ie, a converter controller).

[0035] Reference Figure 1 In step S101, the three-phase voltage value of the station grid connection point received most recently is input into the phase-locked loop PLL to obtain a phase-locked angle, and a reference phase angle is determined based on the phase-locked angle.

[0036] The station grid connection point sends the real-time collected data (including but not limited to the three-phase voltage value of the station grid connection point) to each new energy power generation system in the new energy station that is connected to the power grid through the station grid connection point through a high-speed communication bus. Accordingly, the converter control method of the new energy power generation system according to the exemplary embodiment of the present disclosure may also include: receiving the three-phase voltage value of the station grid connection point in real time.

[0037] As an example, the data collection time point (ie, sampling point) of the converter and the station grid connection point is the same. In other words, the converter and the station grid connection point are sampled synchronously.

[0038] like Figure 3 As shown, as an example, the data synchronization acquisition cycle of the converter and the station grid connection point is the same as the control cycle T of the converter. s (i.e., the execution period of the converter control method) is the same as the length of the switching period T of the three-phase power module on the grid side, and the length of the control period T s Twice the length of d It indicates the communication delay from the substation PCC point to the converter controller (i.e., the transmission delay of the three-phase voltage value of the station grid connection point from the station grid connection point to the converter controller), specifically, the time deviation between the time when the three-phase voltage value of the station grid connection point transmitted from the station grid connection point is received locally and the time when the three-phase voltage value of the station grid connection point is collected. It should be understood that the data synchronization collection cycle is not limited to the same length as the control cycle, and the transmission delay is not limited to be less than the length of the control cycle. For example, the transmission delay can be less than 1ms.

[0039] Taking into account the transmission delay of the three-phase voltage value at the station grid connection point and the phase angle difference of the transformer through which the converter is connected to the station grid connection point, the phase-locked angle can be compensated to obtain a more accurate reference phase angle. As an example, the phase-locked angle can be compensated based on the transmission delay of the three-phase voltage value at the station grid connection point and the phase difference between the high and low voltage sides of the transformer to obtain a reference phase angle.

[0040] As an example, the sum of the phase-locking angle, the first compensation angle used to compensate for the phase difference between the high and low voltage sides of the transformer, and the second compensation angle used to compensate for the transmission delay of the three-phase voltage value of the station grid connection point can be used as the reference phase angle.

[0041] For example, the reference phase angle θ can be calculated by the following formula pcc :

[0042] θpcc =θ0+δ θ0 +δ θ1

[0043] Among them, θ0 represents the phase-locking angle, δ θ0 represents the first compensation angle, δ θ1 Indicates the second compensation angle.

[0044] As an example, the first compensation angle may be determined based on the phase difference between the high and low voltage sides of the transformer. For example, the phase difference between the high and low voltage sides of the transformer is related to the type of the transformer, the connection relationship between the high voltage side and the low voltage side of the transformer, etc. For example, the phase difference between the high and low voltage sides of the transformer may be 30 degrees.

[0045] As an example, the second compensation angle may be determined based on the transmission delay of the three-phase voltage value of the station grid connection point. For example, the transmission delay is related to the length of the communication line and the communication rate.

[0046] In step S102, based on the reference phase angle, the grid-side inductor current value i of the converter collected most recently is la 、i lb 、i lc Perform coordinate transformation to obtain the dq axis positive and negative sequence inductor current values (i.e., the d-axis positive sequence component, q-axis positive sequence component, d-axis negative sequence component, and q-axis negative sequence component of the grid-side inductor current value); the most recently collected grid-side three-phase voltage value v a 、v b 、v c Perform coordinate transformation to obtain the dq axis positive and negative sequence grid side voltage values (That is, the d-axis positive-sequence component, q-axis positive-sequence component, d-axis negative-sequence component, and q-axis negative-sequence component of the three-phase voltage value on the grid side).

[0047] The grid-side inductor current value is the current value flowing through the filter inductor in the grid-side filter.

[0048] Phase-locked loop and coordinate transformation design Figure 4 As shown, combined Figure 3 When the coordinate transformation is performed on the grid-side inductor current value and the grid-side three-phase voltage value collected in the current data synchronization collection cycle, due to the communication delay, the three-phase voltage value of the station grid connection point collected in the current data synchronization collection cycle has not been received, so the reference phase angle used is the three-phase voltage value of the station grid connection point collected in the previous data synchronization collection cycle. The phase angle is obtained by compensating the phase-locked angle.

[0049] In step S103, a dq axis grid side voltage reference value is determined based on the dq axis positive and negative sequence inductor current values ​​and the dq axis positive and negative sequence grid side voltage values.

[0050] It should be understood that the dq axis grid side voltage reference value can be determined in an appropriate manner, and the present disclosure does not limit this. Figure 5 An exemplary embodiment of step S103 is described below, which will not be expanded here.

[0051] In step S104, a PWM signal for controlling a grid-side three-phase power module of the converter is generated based on a dq-axis grid-side voltage reference value and a reference phase angle.

[0052] It should be understood that the reference phase angle is used for coordinate transformation in the process of generating the PWM signal.

[0053] As an example, the grid-side inverter of the converter may include a plurality of three-phase power modules with the same structure (i.e., grid-side three-phase power modules). The three-phase power module may also be referred to as a three-level bridge arm, a three-level topology, or an IGBT module. As an example, each three-phase power module may include a plurality of switch tubes (IGBTs) and diodes connected in reverse parallel thereto.

[0054] As an example, the PWM pulse signal calculation method is not limited to SVPWM.

[0055] According to an exemplary embodiment of the present disclosure, the voltage at the grid-connected point of the station is integrated into the synchronization algorithm for controlling the converter of the renewable energy power generation system group. Based on a high-speed synchronous control system, the grid-side control action rhythm of the converter of the renewable energy power generation system group is consistent, so that the output direction of the renewable energy power generation systems in the same renewable energy station is consistent, thereby improving the fault ride-through capability and operation stability of the renewable energy power generation system under the power grid.

[0056] Figure 5 A flow chart of a method for determining a dq-axis grid-side voltage reference value based on dq-axis positive and negative sequence inductor current values ​​and dq-axis positive and negative sequence grid-side voltage values ​​according to an exemplary embodiment of the present disclosure is shown.

[0057] Reference Figure 5 In step S201, the d-axis inductor current reference value is determined based on the DC voltage target setting value of the converter and the most recently collected DC voltage value and the q-axis positive sequence grid-side voltage value.

[0058] As an example, the difference between the DC voltage target setting value of the converter and the most recently collected DC voltage value can be input into the first PI controller, and then the d-axis inductor current reference value is determined based on the output value of the first PI controller, the q-axis positive-sequence grid-side voltage value, the grid voltage angular frequency, and the grid-side filter capacitance value of the converter.

[0059] As an example, you can Figure 7 The d-axis inductor current reference value is obtained in the manner shown, Indicates the DC voltage target setting value, Vdc Indicates the most recently collected DC voltage value (i.e., DC voltage measurement value). The control deviation is adjusted by the PI controller, plus the feedforward amount Get the d-axis inductor current reference value I d_ref , where ω represents the grid voltage angular frequency (for example, 2π*50 Hz), and C represents the capacitance value of the filter capacitor in the grid-side filter (that is, the grid-side filter capacitance value).

[0060] In step S202, the q-axis inductor current reference value is determined based on the target setting value of the grid-side line voltage effective value of the converter, the most recently acquired grid-side line voltage effective value, the most recently acquired converter reactive power value, and the d-axis positive-sequence grid-side voltage value.

[0061] As an example, the difference between the target setting value of the effective value of the grid-side line voltage of the converter and the effective value of the grid-side line voltage collected most recently can be input into the second PI controller, and then the q-axis inductor current reference value is determined based on the output value of the second PI controller, the reactive value of the converter collected most recently, the d-axis positive-sequence grid-side voltage value, the grid voltage angular frequency, and the grid-side filter capacitance value of the converter.

[0062] As an example, you can Figure 8 The q-axis inductor current reference value is obtained by the method shown, Indicates the target setting value of the effective value of the grid-side line voltage, V rms It represents the effective value of the grid-side line voltage collected most recently (that is, the measured and calculated value of the effective value of the grid-side line voltage). The control deviation is adjusted by the PI controller to obtain the reactive reference set value Q cmd , Q represents the reactive value of the converter collected most recently (i.e., reactive measurement value), and then through PI reactive closed loop and feedforward control, the q-axis inductor current reference value I is obtained. q_ref , where k represents the inertia coefficient.

[0063] In step S203, a dq axis grid side voltage reference value is determined based on the d axis inductor current reference value, the q axis inductor current reference value, the dq axis positive and negative sequence inductor current values, and the dq axis positive and negative sequence grid side voltage values.

[0064] It should be understood that the dq axis grid side voltage reference value can be determined based on the d axis inductor current reference value, the q axis inductor current reference value, the dq axis positive and negative sequence inductor current values, and the dq axis positive and negative sequence grid side voltage values ​​in an appropriate manner, and the present disclosure does not limit this. Figure 6 An exemplary embodiment of step S203 is described below, which will not be expanded here.

[0065] Figure 6A flow chart of a method for determining a dq axis grid side voltage reference value according to an exemplary embodiment of the present disclosure is shown.

[0066] Reference Figure 6 In step S301, a d-axis positive-sequence grid-side voltage reference value is determined based on the d-axis inductor current reference value, the dq-axis positive-sequence inductor current value, and the d-axis positive-sequence grid-side voltage value.

[0067] As an example, the difference between the d-axis inductor current reference value and the d-axis positive-sequence inductor current value can be input into the third PI controller, and then the d-axis positive-sequence grid-side voltage reference value is determined based on the output value of the third PI controller, the q-axis positive-sequence inductor current value, the d-axis positive-sequence grid-side voltage value, the grid-side filter inductance value, and the grid voltage angular frequency.

[0068] In step S302, a q-axis positive-sequence grid-side voltage reference value is determined based on the q-axis inductor current reference value, the dq-axis positive-sequence inductor current value, and the q-axis positive-sequence grid-side voltage value.

[0069] As an example, the difference between the q-axis inductor current reference value and the q-axis positive-sequence inductor current value can be input into the fourth PI controller, and then the q-axis positive-sequence grid-side voltage reference value is determined based on the output value of the fourth PI controller, the d-axis positive-sequence inductor current value, the q-axis positive-sequence grid-side voltage value, the grid-side filter inductance value, and the grid voltage angular frequency.

[0070] In step S303, a d-axis negative-sequence grid-side voltage reference value is determined based on the dq-axis negative-sequence inductor current value and the d-axis negative-sequence grid-side voltage value.

[0071] As an example, the difference between 0 and the d-axis negative-sequence inductor current value can be input into the fifth PI controller, and then the d-axis negative-sequence grid-side voltage reference value is determined based on the output value of the fifth PI controller, the q-axis negative-sequence inductor current value, the d-axis negative-sequence grid-side voltage value, the grid-side filter inductance value, and the grid voltage angular frequency.

[0072] In step S304, a q-axis negative-sequence grid-side voltage reference value is determined based on the dq-axis negative-sequence inductor current value and the q-axis negative-sequence grid-side voltage value.

[0073] As an example, the difference between 0 and q-axis negative-sequence inductor current values ​​can be input into the sixth PI controller, and then the q-axis negative-sequence grid-side voltage reference value is determined based on the output value of the sixth PI controller, the d-axis negative-sequence inductor current value, the q-axis negative-sequence grid-side voltage value, the grid-side filter inductance value, and the grid voltage angular frequency.

[0074] In step S305, based on the d-axis positive and negative sequence grid-side voltage reference value and the q-axis positive and negative sequence grid-side voltage reference value, a dq-axis grid-side voltage reference value is determined.

[0075] As an example, the sum of the d-axis positive and negative sequence grid-side voltage reference values ​​may be used as the d-axis grid-side voltage reference value.

[0076] As an example, the sum of the q-axis positive and negative sequence grid-side voltage reference values ​​may be used as the q-axis grid-side voltage reference value.

[0077] like Fig. 9 As shown, the current inner loop design adopts separate control of positive and negative sequences. L represents the inductance value of the filter inductor in the grid-side filter (that is, the grid-side filter inductance value). For the positive sequence design, the positive sequence grid-side voltage dq axis reference value is obtained through PI closed loop and feedforward control. and In the negative sequence design, the target current value of the current loop dq axis is set to 0, and the negative sequence grid side voltage dq axis reference value is obtained through PI closed loop and feedforward control. and After summing with the positive sequence calculated value, pulses are output through the SVPWM mode.

[0078] It should be understood that the voltage outer loop design, reactive power loop design, and current inner loop design in the above embodiments may also adopt other design forms.

[0079] According to an exemplary embodiment of the present disclosure, a station-level synchronous control method is proposed for the grid-connected side of the converter, and the PCC point voltage phase-locked angle is directly involved in the synchronous control of the inner and outer loops of the converters of each renewable energy power generation system, so that the renewable energy power generation system group has the effect of synchronous control.

[0080] According to the exemplary embodiments of the present disclosure, it is possible to solve the stability problem of the grid-connected operation of the renewable energy power generation system when the renewable energy grid accounts for a high proportion and the grid is weak, thereby effectively increasing the proportion of the renewable energy grid.

[0081] According to the converter control method of the new energy power generation system of the exemplary embodiment of the present disclosure, the power grid to which the new energy power generation system is connected via the station grid connection point may include a weak power grid, which is characterized by a system short-circuit capacity ratio SCR within a predetermined range.

[0082] According to the converter control method of the new energy power generation system of the exemplary embodiment of the present disclosure, the new energy power generation system group has the dynamic properties of synchronous control, synchronous response and synchronous execution. Fig.10A set of PSCAD (Power Systems Computer Aided Design, electromagnetic transient simulation software) low voltage ride-through capability simulation data is shown, wherein the SCR (Short Circuit Ratio, system short circuit capacity ratio) indicator is the minimum boundary value of SCR under the premise that low voltage ride-through can be passed. The simulation data show that the converter control method of the new energy power generation system according to the exemplary embodiment of the present disclosure can adapt to lower SCR, and the fault ride-through capability is significantly enhanced compared with the conventional control method.

[0083] In addition, under the same grid conditions, PSCAD and RTDS (Real Time Data Simulator) simulation data show that the converter control method of the new energy power generation system according to the exemplary embodiment of the present disclosure is expected to increase the proportion of new energy by more than 15% while ensuring the stable operation of the grid.

[0084] An exemplary embodiment of the present disclosure provides a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to execute the converter control method of the renewable energy power generation system as described in the above exemplary embodiment. The computer-readable storage medium is any data storage device that can store data read out by a computer system. Examples of computer-readable storage media include: read-only memory, random access memory, read-only optical disk, magnetic tape, floppy disk, optical data storage device, and carrier wave (such as data transmission through the Internet via a wired or wireless transmission path).

[0085] According to the exemplary embodiment of the present disclosure, the converter controller of the renewable energy power generation system includes: a processor and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, it prompts the processor to execute the converter control method of the renewable energy power generation system as described in the above exemplary embodiment.

[0086] A new energy power generation system according to an exemplary embodiment of the present disclosure includes: a converter and a converter controller as described in the above exemplary embodiment.

[0087] Although some exemplary embodiments of the present disclosure have been shown and described, it will be appreciated by those skilled in the art that modifications may be made to these embodiments without departing from the scope and spirit of the present disclosure as defined by the claims and their equivalents.

Claims

1. A converter control method for a new energy power generation system, characterized in that: The converter control method comprises: Inputting the most recently received three-phase voltage value of the station grid connection point into a phase-locked loop to obtain a phase-locked angle, and determining a reference phase angle based on the phase-locked angle; Based on the reference phase angle, coordinate transformation is performed on the grid-side inductor current value of the converter collected most recently to obtain dq-axis positive and negative-sequence inductor current values, and coordinate transformation is performed on the grid-side three-phase voltage value of the converter collected most recently to obtain dq-axis positive and negative-sequence grid-side voltage values; Determine a dq axis grid side voltage reference value based on the dq axis positive and negative sequence inductor current value and the dq axis positive and negative sequence grid side voltage value; Based on the dq axis grid-side voltage reference value and the reference phase angle, a PWM signal for controlling a grid-side three-phase power module of the converter is generated.

2. The converter control method according to claim 1, characterized in that: The data collection time point of the converter is the same as that of the station grid connection point; The step of determining the reference phase angle based on the phase-locking angle includes: compensating the phase-locking angle based on the transmission delay of the three-phase voltage value of the station grid connection point and the phase difference between the high and low voltage sides of the transformer to obtain the reference phase angle; Wherein, the converter is connected to the station grid connection point via the transformer; The transmission delay is the transmission delay of the three-phase voltage value of the station grid connection point from the station grid connection point to the converter.

3. The converter control method according to claim 2, characterized in that: Based on the transmission delay of the three-phase voltage value of the station grid connection point and the phase difference between the high and low voltage sides of the transformer, the phase-locked angle is compensated to obtain the reference phase angle, which includes: The sum of the phase-locking angle, the first compensation angle for compensating the phase difference between the high and low voltage sides, and the second compensation angle for compensating the transmission delay is used as the reference phase angle.

4. The converter control method according to claim 2, characterized in that: The data synchronization acquisition cycle of the converter and the station grid connection point is the same as the control cycle of the converter, and the switching cycle of the grid-side three-phase power module is twice the control cycle; And / or, the transmission delay is less than 1 ms.

5. The converter control method according to any one of claims 1 to 4, characterized in that: The system short-circuit capacity ratio SCR of the power grid to which the new energy power generation system is connected via the station grid connection point is within a predetermined range.

6. The converter control method according to claim 1, characterized in that: The step of determining a dq axis grid side voltage reference value based on the dq axis positive and negative sequence inductor current value and the dq axis positive and negative sequence grid side voltage value comprises: Determine a d-axis inductor current reference value based on a DC voltage target setting value of the converter, a most recently acquired DC voltage value, and a q-axis positive-sequence grid-side voltage value; Determine the q-axis inductor current reference value based on the target setting value of the grid-side line voltage effective value of the converter, the most recently acquired grid-side line voltage effective value, the most recently acquired reactive power value of the converter, and the d-axis positive-sequence grid-side voltage value; A dq axis grid side voltage reference value is determined based on the d axis inductor current reference value, the q axis inductor current reference value, the dq axis positive and negative sequence inductor current values, and the dq axis positive and negative sequence grid side voltage values.

7. The converter control method according to claim 6, characterized in that: Based on the d-axis inductor current reference value, the q-axis inductor current reference value, the dq-axis positive and negative sequence inductor current values, and the dq-axis positive and negative sequence grid-side voltage values, the step of determining the dq-axis grid-side voltage reference value includes: Determine a d-axis positive-sequence grid-side voltage reference value based on the d-axis inductor current reference value, the dq-axis positive-sequence inductor current value, and the d-axis positive-sequence grid-side voltage value; Determine a q-axis positive-sequence grid-side voltage reference value based on the q-axis inductor current reference value, the dq-axis positive-sequence inductor current value, and the q-axis positive-sequence grid-side voltage value; Determine a d-axis negative-sequence grid-side voltage reference value based on the dq-axis negative-sequence inductor current value and the d-axis negative-sequence grid-side voltage value; Determine a q-axis negative-sequence grid-side voltage reference value based on the dq-axis negative-sequence inductor current value and the q-axis negative-sequence grid-side voltage value; The dq-axis grid-side voltage reference value is determined based on the d-axis positive- and negative-sequence grid-side voltage reference value and the q-axis positive- and negative-sequence grid-side voltage reference value.

8. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the processor is prompted to execute the converter control method for a new energy power generation system according to any one of claims 1 to 7.

9. A current converter controller for a new energy power generation system, characterized in that: The current converter controller comprises: processor; A memory storing a computer program, which, when executed by a processor, prompts the processor to execute the converter control method for a new energy power generation system as claimed in any one of claims 1 to 7.

10. A new energy power generation system, characterized in that: The new energy power generation system comprises a converter and a converter controller as claimed in claim 9.

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