Rectifier starting control method and system considering inertia transfer link

Abstract

The invention relates to the technical field of power electronics, in particular to a rectifier starting control method and system considering an inertia transfer link. The pre-charging resistors at the alternating current side and the direct current side are bypassed in sequence, so that the rectifier firstly works in an uncontrolled rectification mode and has relatively appropriate direct current voltage, and then PWM pulses are started and a current reference value is linearly increased from 0 until saturation; aC side overcurrent and DC overvoltage in the rectifier starting process can be effectively suppressed.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and in particular to a rectifier startup control method and system considering an inertia transfer link. Background Art

[0002] The three-phase PWM rectifier serves as the front-stage constant power control unit in the grid-type direct-drive wind turbine. It converts the three-phase AC input voltage into a DC voltage output, transferring power from the machine side of the new energy power generation unit to the grid-side inverter. In addition, by adding an inertia transfer link, the three-phase PWM rectifier can effectively capture DC voltage changes and thus sense grid frequency changes, allowing the rectifier to increase input power and transfer additional machine-side energy to the grid side, thereby achieving inertia support.

[0003] However, starting and controlling a grid-connected direct-drive wind turbine with inertia transfer is difficult. The input of a traditional three-phase PWM rectifier requires a complex pre-charging process for the DC capacitors, making the startup process highly dependent on pre-charging the DC capacitors. During startup, the transient charging effect of the rectifier input voltage on the DC voltage increases the risk of DC overvoltage. Summary of the Invention

[0004] In response to the problems in the prior art, the present invention provides a rectifier startup control method and system that takes into account the inertia transfer link. Unlike the traditional startup method, the AC side pre-charging resistor is first bypassed to make the converter work in the uncontrolled rectification mode, and then the DC side pre-charging resistor is bypassed to further increase the DC voltage. When it is detected that all the AC and DC side pre-charging resistors are bypassed, the PWM pulse signal is enabled and the current reference value is linearly increased from 0 until saturation. Finally, after the system stabilizes, the inertia transfer control link is introduced into the current reference value to realize the rectifier startup control that takes into account the inertia transfer link. The specific technical solution is as follows:

[0005] A rectifier startup control method considering an inertia transfer link comprises the following steps:

[0006] Step S1, collecting the rectifier grid connection point voltage V pcc and the rectifier grid-connected point input current I g , and based on the phase-locked loop control, the rectifier grid-connected point voltage V pcc The projection value V on the dq axis of the rectifier phase-locked loop control pccd 、V pccq And the projection of the rectifier grid-connected point input current on the dq axis of the rectifier grid-connected point I gd , I gq ;

[0007] Step S2: Detect the projection value V of the input voltage on the AC side of the rectifier on the q axis of the rectifier phase-locked loop control.pccq Less than a given threshold ε q , enable the rectifier start flag S C ;

[0008] Step S3, after a delay of Δt1, bypass the rectifier AC side pre-charging resistor R S_AC , bypass the pre-charge resistor on the AC side of the rectifier to put the rectifier into uncontrolled rectification mode, and calculate the rectifier output DC voltage V dc ;

[0009] Step S4: Detect the rectifier AC side pre-charge resistor bypass flag S C_AC After a delay of Δt2, the rectifier DC side pre-charge resistor bypass flag S is enabled. C_DC , bypass rectifier DC side pre-charge resistor R S_DC Step S5, after detecting that the rectifier AC side pre-charge resistor and the rectifier DC side pre-charge resistor are bypassed, the PWM pulse flag S is started after a delay of Δt3 P , and enable the current inner loop control at the same time, enable the d-axis current reference value I of the current inner loop control dref It increases linearly from 0 and eventually reaches saturation;

[0010] Step S6: Detect the actual value of the rectifier DC voltage V dc With reference value V dcref The deviation is less than the given threshold ε dc , enable inertia transfer control flag S I , according to the current output by the inertia transfer control, adjust the d-axis current reference value I of the current inner loop control dref , the d-axis current reference value I of the current inner loop control adjusted after considering inertia transfer is obtained dref ';

[0011] Step S7: The d-axis current reference value I of the current inner loop control adjusted after considering the inertia transfer is dref 'Input current inner loop control, according to the rectifier grid voltage V pcc The projection value V on the dq axis of the rectifier phase-locked loop control pccd 、V pccq And the rectifier grid-connected point input current I g Projection I on the dq axis of the rectifier grid connection point gd , I gq The PWM control signal is generated to control the operating state of the rectifier.

[0012] Preferably, the control equation of the phase-locked loop control in step S1 is as follows:

[0013]

[0014] Where T represents the time constant of the sampling low-pass filter; K P_PLL and K I_PLL Respectively represent the proportional gain and integral gain of the phase-locked loop control; δ PLL Represents the phase difference between the phase of the phase-locked loop control output and the phase of the rectifier AC side input voltage, ω PLL is the output frequency of the phase-locked loop control; ω0 is the rated frequency of the grid voltage.

[0015] Preferably, the actual value of the rectifier DC voltage V in step S3 is dc is calculated as follows:

[0016]

[0017] Preferably, the d-axis current reference value I of the current inner loop control in step S5 is dref It starts from 0 and increases linearly and eventually reaches saturation as follows:

[0018]

[0019] Where k represents the d-axis current reference value I of the current inner loop control dref The slope of the linear growth with time t, I dref_max Represents the d-axis current reference value I of the current inner loop control dref saturation value.

[0020] Preferably, the current output according to the inertia transfer control is calculated as follows:

[0021]

[0022] Among them, I In Represents the current output by the inertia transfer link; K C represents the proportional gain of the inertia transfer link; T represents the time constant of the low-pass filter in the inertia transfer link; α represents the lead correction coefficient of the lead correction link in the inertia transfer link; T l represents the advance correction time constant of the advance correction link in the inertia transfer link; β represents the lag correction coefficient of the lag correction link in the inertia transfer link; T d Represents the lag correction time constant of the lag correction link in the inertia transfer link.

[0023] Preferably, the d-axis current reference value I of the current inner loop control is adjusted according to the current output by the inertia transfer control. dref The details are as follows:

[0024] I dref '=I dref_max +I In ;(5)

[0025] Among them, I dref ' represents the d-axis current reference value of the current inner loop control adjusted after considering inertia transfer; I In Represents the current output by the inertia transfer link.

[0026] Preferably, the control equation of the current inner loop control in step S7 is as follows:

[0027]

[0028] Among them, U td and U tq They represent the projection of the rectifier PWM modulation signal on the dq axis of the rectifier grid connection point; L f Represents the rectifier input filter inductance value; U ta 、U tb and U tc Respectively represent the three-phase modulation signals input to the SPWM modulation module; ω n K is the rated frequency of the input voltage on the AC side of the rectifier; pc and K ic They represent the proportional gain and integral gain of the current inner loop control respectively.

[0029] A rectifier startup control system considering the inertia transfer link, applying the method described above, includes: a collection and processing module for collecting the rectifier grid connection point voltage V pcc and the rectifier grid-connected point input current I g , and based on the phase-locked loop control, the rectifier grid-connected point voltage V pcc The projection value V on the dq axis of the rectifier phase-locked loop control pccd 、V pccq And the projection of the rectifier grid-connected point input current on the dq axis of the rectifier grid-connected point I gd , I gq The first processing module is used to detect the projection value V of the rectifier AC side input voltage on the rectifier phase-locked loop control q axis pccq Less than a given threshold ε q , enable the rectifier start flag S C ;

[0030] The second processing module is used to bypass the rectifier AC side pre-charging resistor R after a delay of Δt1 S_AC , bypass the pre-charge resistor on the AC side of the rectifier to put the rectifier into uncontrolled rectification mode, and calculate the rectifier output DC voltage V dc ;

[0031] The third processing module is used to detect the bypass flag S of the pre-charging resistor on the AC side of the rectifier C_AC After a delay of Δt2, the rectifier DC side pre-charge resistor bypass flag S is enabled.C_DC , bypass rectifier DC side pre-charge resistor R S_DC ;

[0032] The fourth processing module detects that the rectifier AC side pre-charging resistor and the rectifier DC side pre-charging resistor are both bypassed, and then starts the PWM pulse flag S after a delay of Δt3. P , and enable the current inner loop control at the same time, enable the d-axis current reference value I of the current inner loop control dref It increases linearly from 0 and eventually reaches saturation;

[0033] The fifth processing module detects the actual value of the rectifier DC voltage V dc With reference value V dcref The deviation is less than the given threshold ε dc , enable inertia transfer control flag S I , according to the current output by the inertia transfer control, adjust the d-axis current reference value I of the current inner loop control dref , the d-axis current reference value I of the current inner loop control adjusted after considering inertia transfer is obtained dref ';

[0034] The sixth processing module is used to adjust the d-axis current reference value I of the current inner loop control after considering the inertia transfer dref 'Input current inner loop control, according to the rectifier grid voltage V pcc The projection value V on the dq axis of the rectifier phase-locked loop control pccd 、V pccq And the rectifier grid-connected point input current I g Projection I on the dq axis of the rectifier grid connection point gd , I gq The PWM control signal is generated to control the operating state of the rectifier.

[0035] A computer-readable storage medium includes a stored program, wherein when the program is run, the device where the computer-readable storage medium is located is controlled to execute the rectifier startup control method considering the inertia transfer link.

[0036] A processor is used to run a program, wherein the program executes the rectifier startup control method considering the inertia transfer link when running.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The present invention bypasses the AC side and DC side pre-charging resistors in sequence, so that the rectifier first operates in an uncontrolled rectification mode and has a relatively suitable DC voltage, and then starts the PWM pulse and makes the current reference value linearly increase from 0 until saturation, which can effectively suppress AC side overcurrent and DC overvoltage during the rectifier startup process. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly describes the drawings required for the specific embodiments or the description of the prior art. Similar elements or parts are generally identified by similar reference numerals throughout the drawings. Elements or parts in the drawings are not necessarily drawn to scale.

[0040] Figure 1 It is a schematic diagram of the main circuit topology of a three-phase PWM rectifier and the principle diagram of the rectifier startup control method considering inertia transfer control adopted by the present invention.

[0041] Figure 2 This is the relationship diagram between the rectifier phase-locked loop output phase and the input voltage phase.

[0042] Figure 3 The figure is a logic flow chart of the startup method of the present invention.

[0043] Figure 4 This is the rectifier startup waveform after adopting the startup method of the present invention. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0045] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0046] It should also be understood that the terms used in the present specification are only for the purpose of describing particular embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0047] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0048] Example 1:

[0049] like Figure 1 As shown, this embodiment provides a rectifier startup control method considering the inertia transfer link, including the following steps:

[0050] Step S1, collecting the rectifier grid connection point voltage V pcc and the rectifier grid-connected point input current I g , and based on the phase-locked loop control, the rectifier grid-connected point voltage V pcc The projection value V on the dq axis of the rectifier phase-locked loop control pccd 、V pccq And the projection of the rectifier grid-connected point input current on the dq axis of the rectifier grid-connected point I gd , I gq .

[0051] The control equation of the phase-locked loop control is as follows:

[0052]

[0053] Where T represents the time constant of the sampling low-pass filter; K P_PLL and K I_PLL Respectively represent the proportional gain and integral gain of the phase-locked loop control; δ PLL Represents the phase difference between the phase of the phase-locked loop control output and the phase of the rectifier AC side input voltage, ω PLL is the output frequency of the phase-locked loop control; ω0 is the rated frequency of the grid voltage. pcc The projection value V on the q axis of the rectifier phase-locked loop control pccq is calculated as follows:

[0054] V pccq =-V g cosδ PLL ;(2).

[0055] Figure 2 The relationship between the inverter phase-locked loop control output phase and the grid voltage phase is plotted. c and q c They represent the d-axis and q-axis coordinate systems constructed by the inverter’s phase-locked loop control, d g and q g They represent the d-axis and q-axis coordinate systems corresponding to the grid voltage respectively.

[0056] Step S2: Detect the projection value V of the grid voltage on the q axis of the rectifier phase-locked loop control. pccq Less than a given threshold ε q , enable the rectifier start flag S C =1.

[0057] Step S3, after a delay of Δt1 = 3 seconds, enable the AC side pre-charging resistor bypass signal S C_AC =1, bypass the rectifier AC side pre-charge resistor R S_AC , so that the rectifier enters the uncontrolled rectification operation mode, and calculates the rectifier output DC voltage V dc The rectifier outputs a DC voltage V dc The expression is:

[0058]

[0059] Among them, V g Represents the AC side input grid voltage of the three-phase PWM rectifier.

[0060] Step S4: Detect the rectifier AC side pre-charge resistor bypass flag S C_AC =1, after delay Δt2=3 seconds, enable the DC pre-charge resistor bypass flag S C_DC =1, bypass the rectifier DC side pre-charge resistor R S_DC , at this time the DC voltage will increase further.

[0061] Step S5, detecting the AC side pre-charging resistor bypass signal S C_AC and DC side pre-charge resistor bypass signal S C_DC When both are 1, that is, after the rectifier AC side pre-charging resistor and the rectifier DC side pre-charging resistor are bypassed, the PWM pulse flag S is started after a delay of Δt3 = 3 seconds. P , and enable the current inner loop control and the current reference value I dref It increases linearly from 0 and eventually reaches saturation. The specific expression is as follows:

[0062]

[0063] Where k represents the d-axis current reference value I of the current inner loop control dref The slope of the linear growth with time t, I dref_max Represents the d-axis current reference value I of the current inner loop control dref saturation value.

[0064] Step S6: Detect the actual value of the rectifier DC voltage V dc The deviation from the reference value is less than the given threshold ε dc , enable inertia transfer control flag S I, according to the current output by the inertia transfer control, adjust the d-axis current reference value I of the current inner loop control dref , the d-axis current reference value I of the current inner loop control adjusted after considering inertia transfer is obtained dref '.

[0065] The calculation method of the output current of the inertia transfer control is as follows:

[0066]

[0067] Among them, I In Represents the current output by the inertia transfer link; K C represents the proportional gain of the inertia transfer link; T represents the time constant of the low-pass filter in the inertia transfer link; α represents the lead correction coefficient of the lead correction link in the inertia transfer link; T l represents the advance correction time constant of the advance correction link in the inertia transfer link; β represents the lag correction coefficient of the lag correction link in the inertia transfer link; T d Represents the lag correction time constant of the lag correction link in the inertia transfer link.

[0068] The inertia transfer link detects the output voltage V of the rectifier dc , first of all, V dc Perform low-pass filtering and then extract V through the differential link dc The differential dynamics, and through the second-order lead-lag link output I In .

[0069] Adjust the d-axis current reference value I of the current inner loop control according to the current output of the inertia transfer control dref The details are as follows:

[0070] I dref '=I dref_max +I In ;(6).

[0071] I dref ' represents the d-axis current reference value of the current inner loop control adjusted after taking into account inertia transfer. When the load resistance suddenly changes, an additional current reference value is output by detecting the DC voltage change, thereby increasing the active power, simulating the inertia response characteristics of the new energy power generation unit, and providing inertia support.

[0072] Step S7: The d-axis current reference value I of the current inner loop control adjusted after considering the inertia transfer is dref 'Input current inner loop control, according to the rectifier grid voltage V pcc The projection value V on the dq axis of the rectifier phase-locked loop control pccd 、V pccq And the rectifier grid-connected point input current I gProjection I on the dq axis of the rectifier grid connection point gd , I gq The PWM control signal is generated to control the operating state of the rectifier.

[0073] The control equation of the current inner loop control is as follows:

[0074]

[0075] According to U td and U tq Generate PWM control signal, the specific process is as follows:

[0076]

[0077] Among them, U td and U tq They represent the projection of the rectifier PWM modulation signal on the dq axis of the rectifier grid connection point; L f Represents the rectifier input filter inductance value; U ta 、U tb and U tc Respectively represent the three-phase modulation signals input to the SPWM modulation module; ω n K is the rated frequency of the input voltage on the AC side of the rectifier; pc and K ic They represent the proportional gain and integral gain of the current inner loop control respectively. The three-phase modulation signal is compared with the triangular carrier to generate the PWM signal.

[0078] Figure 3 A rectifier startup logic flow chart considering the inertia transfer link was drawn, and the rectifier startup control considering the inertia transfer link was completed by successively enabling the rectifier startup control flag, the AC side and DC side pre-charging resistor bypass signals, and the inertia transfer link enable signal.

[0079] When implementing it specifically, Figure 4 As shown, at the moment of startup, the rectifier input q-axis voltage V pccq Less than a given threshold ε q , enable the rectifier start control flag S C , after a delay of 3 seconds, the AC side pre-charge resistor bypass signal S is enabled C_AC , bypass the AC side pre-charge resistor R S_AC , the rectifier enters the uncontrolled rectification mode, and the DC voltage increases. Then, after a delay of 3 seconds, the DC side pre-charge resistor bypass signal S is enabled. C_DC , bypass the DC side pre-charge resistor R S_DC , the DC voltage increases further. Detect S C_AC and S C_DC After all are enabled, delay 3 seconds and enable PWM pulse signal SP , the rectifier enters the closed-loop PWM rectification mode, the current reference value I dref It starts to increase linearly, and the output current on the AC side increases rapidly. Detect the DC voltage V dc and V dcref The deviation is less than the given threshold ε dc , enable the inertia transfer control link enable signal S I At this point, fluctuations in the DC voltage are fed back to the rectifier's power output via the inertia transfer link. Ultimately, rectifier startup control that considers the inertia transfer link is complete. During the aforementioned rectifier startup process, no severe output overcurrent occurred, and the output DC voltage exhibited a good dynamic response, demonstrating that the present method is capable of implementing rectifier startup control that considers the inertia transfer link.

[0080] Example 2:

[0081] Based on the same inventive concept as Example 1, this embodiment provides a rectifier startup control system that takes into account the inertia transfer link. Applying the described method, the control system includes:

[0082] The acquisition and processing module is used to collect the rectifier grid connection point voltage V pcc and the rectifier grid-connected point input current I g , and based on the phase-locked loop control, the rectifier grid-connected point voltage V pcc The projection value V on the dq axis of the rectifier phase-locked loop control pccd 、V pccq And the projection of the rectifier grid-connected point input current on the dq axis of the rectifier grid-connected point I gd , I gq The first processing module is used to detect the projection value V of the rectifier AC side input voltage on the rectifier phase-locked loop control q axis pccq Less than a given threshold ε q , enable the rectifier start flag S C ;

[0083] The second processing module is used to bypass the rectifier AC side pre-charging resistor R after a delay of Δt1 S_AC , bypass the pre-charge resistor on the AC side of the rectifier to put the rectifier into uncontrolled rectification mode, and calculate the rectifier output DC voltage V dc ;

[0084] The third processing module is used to detect the bypass flag S of the pre-charging resistor on the AC side of the rectifier C_AC After a delay of Δt2, the rectifier DC side pre-charge resistor bypass flag S is enabled. C_DC , bypass rectifier DC side pre-charge resistor R S_DC ;

[0085] The fourth processing module detects that the rectifier AC side pre-charging resistor and the rectifier DC side pre-charging resistor are both bypassed, and then starts the PWM pulse flag S after a delay of Δt3. P , and enable the current inner loop control at the same time, enable the d-axis current reference value I of the current inner loop control dref It increases linearly from 0 and eventually reaches saturation;

[0086] The fifth processing module detects the actual value of the rectifier DC voltage V dc With reference value V dcref The deviation is less than the given threshold ε dc , enable inertia transfer control flag S I , according to the current output by the inertia transfer control, adjust the d-axis current reference value I of the current inner loop control dref , the d-axis current reference value I of the current inner loop control adjusted after considering inertia transfer is obtained dref ';

[0087] The sixth processing module is used to adjust the d-axis current reference value I of the current inner loop control after considering the inertia transfer dref 'Input current inner loop control, according to the rectifier grid voltage V pcc The projection value V on the dq axis of the rectifier phase-locked loop control pccd 、V pccq And the rectifier grid-connected point input current I g Projection I on the dq axis of the rectifier grid connection point gd , I gq The PWM control signal is generated to control the operating state of the rectifier.

[0088] Figure 1 The main circuit topology and startup control block diagram of the rectifier considering the inertia transfer link are drawn. C Represents the rectifier startup control flag, S C_AC and S C_DC Respectively represent the pre-charge resistor bypass signal on the AC side and DC side, S I Indicates the inertia transfer link enable signal.

[0089] This embodiment builds Figure 1 (a) The rectifier topology model and Figure 1 (b) The control topology model shown in the rectifier topology model is as follows: the rectifier is connected to the AC side of the rectifier through the filter inductor Lf and the pre-charge resistor R S_AC Connected to the grid, and the rectifier AC side pre-charging resistor R S_AC Parallel AC side pre-charging resistor bypass switch S C_AC , rectifier DC side pre-charge resistor R S_DC Parallel DC side pre-charging resistor bypass switch SC_DC , the rectifier is connected to the PWM signal output by the control topology model through the pulse enable switch Sp.

[0090] The control topology model includes an inertia transfer link module, a current reference value slow increase module, a phase-locked loop control module, and a current inner loop control module;

[0091] The inertia transfer link module enables the inertia switch S I The current inner loop control module is connected, the current reference value slow increase module is connected to the current inner loop control module, the phase-locked loop control module is connected to the acquisition and processing module of the control system, and the current inner loop control module is connected to the rectifier through the pulse enable switch Sp.

[0092] Example 3:

[0093] Based on the same inventive concept as Example 1, this embodiment provides a computer-readable storage medium, which includes a stored program, wherein when the program is running, the device where the computer-readable storage medium is located is controlled to execute the rectifier startup control method considering the inertia transfer link.

[0094] Example 4:

[0095] Based on the same inventive concept as that of Example 1, this embodiment provides a processor, which is used to run a program, wherein the rectifier startup control method considering the inertia transfer link is executed when the program is running.

[0096] Those skilled in the art will appreciate that the modules of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition of each example has been generally described in terms of function in the above description. 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.

[0097] In the embodiments provided by the present invention, it should be understood that the division of modules is merely a logical function division, and there may be other division methods in actual implementation, for example, multiple modules can be combined into one module, one module can be split into multiple modules, or some features can be ignored, etc.

[0098] In addition, the functional modules in various embodiments of the present invention may be integrated into a single processing module, or each module may exist physically separately, or two or more modules may be integrated into a single module. The aforementioned integrated modules may be implemented in the form of hardware or software functional modules.

[0099] If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-0nly Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk, etc., various media that can store program code.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

Claims

1. A rectifier startup control method considering the inertia transfer link, characterized in that: The following steps are involved: Step S1, collecting the rectifier grid connection point voltage V pcc and the rectifier grid-connected point input current I g , and based on the phase-locked loop control, the rectifier grid-connected point voltage V pcc The projection value V on the dq axis of the rectifier phase-locked loop control pccd 、V pccq And the projection of the rectifier grid-connected point input current on the dq axis of the rectifier grid-connected point I gd , I gq ; Step S2: Detect the projection value V of the input voltage on the AC side of the rectifier on the q axis of the rectifier phase-locked loop control. pccq Less than a given threshold ε q , enable the rectifier start flag S C ; Step S3, after a delay of Δt1, bypass the rectifier AC side pre-charging resistor R S_AC , bypass the pre-charge resistor on the AC side of the rectifier to put the rectifier into uncontrolled rectification mode, and calculate the rectifier output DC voltage V dc ; Step S4: Detect the rectifier AC side pre-charge resistor bypass flag S C_AC After a delay of Δt2, the rectifier DC side pre-charge resistor bypass flag S is enabled. C_DC , bypass rectifier DC side pre-charge resistor R S_DC ; Step S5: After detecting that the rectifier AC side pre-charging resistor and the rectifier DC side pre-charging resistor are both bypassed, the PWM pulse flag S is started after a delay of Δt3. P , and enable the current inner loop control at the same time, enable the d-axis current reference value I of the current inner loop control dref It increases linearly from 0 and eventually reaches saturation; Step S6: Detect the actual value of the rectifier DC voltage V dc With reference value V dcref The deviation is less than the given threshold ε dc , enable inertia transfer control flag S I , according to the current output by the inertia transfer control, adjust the d-axis current reference value I of the current inner loop control dref , the d-axis current reference value I of the current inner loop control adjusted after considering inertia transfer is obtained dref '; Step S7: The d-axis current reference value I of the current inner loop control adjusted after considering the inertia transfer is dref 'Input current inner loop control, according to the rectifier grid voltage V pcc The projection value V on the dq axis of the rectifier phase-locked loop control pccd 、V pccq And the rectifier grid-connected point input current I g Projection I on the dq axis of the rectifier grid connection point gd , I gq The PWM control signal is generated to control the operating state of the rectifier.

2. The rectifier startup control method considering the inertia transfer link according to claim 1 is characterized in that: The control equation of the phase-locked loop control in step S1 is as follows: Where T represents the time constant of the sampling low-pass filter; K P_PLL and K I_PLL Respectively represent the proportional gain and integral gain of the phase-locked loop control; δ PLL Represents the phase difference between the phase of the phase-locked loop control output and the phase of the rectifier AC side input voltage, ω PLL is the output frequency of the phase-locked loop control; ω0 is the rated frequency of the grid voltage.

3. The rectifier startup control method considering the inertia transfer link according to claim 1 is characterized in that: In step S3, the actual value of the rectifier DC voltage V dc is calculated as follows:

4. The rectifier startup control method considering the inertia transfer link according to claim 1 is characterized in that: The d-axis current reference value I of the current inner loop control in step S5 dref It starts from 0 and increases linearly and eventually reaches saturation as follows: Where k represents the d-axis current reference value I of the current inner loop control dref The slope of the linear growth with time t, I dref_max Represents the d-axis current reference value I of the current inner loop control dref saturation value.

5. The rectifier startup control method considering the inertia transfer link according to claim 1 is characterized in that: The calculation method of the output current of the inertia transfer control is as follows: Among them, I In Represents the current output by the inertia transfer link; K C represents the proportional gain of the inertia transfer link; T represents the time constant of the low-pass filter in the inertia transfer link; α represents the lead correction coefficient of the lead correction link in the inertia transfer link; T l represents the advance correction time constant of the advance correction link in the inertia transfer link; β represents the lag correction coefficient of the lag correction link in the inertia transfer link; T d Represents the lag correction time constant of the lag correction link in the inertia transfer link.

6. The rectifier startup control method considering the inertia transfer link according to claim 1 is characterized in that: Adjust the d-axis current reference value I of the current inner loop control according to the current output of the inertia transfer control dref The details are as follows: I dref '=I dref_max +I In ;(5) Among them, I dref ' represents the d-axis current reference value of the current inner loop control adjusted after considering inertia transfer; I In Represents the current output by the inertia transfer link.

7. The rectifier startup control method considering the inertia transfer link according to claim 1 is characterized in that: The control equation of the current inner loop control in step S7 is as follows: Among them, U td and U tq They represent the projection of the rectifier PWM modulation signal on the dq axis of the rectifier grid connection point; L f Represents the rectifier input filter inductance value; U ta 、U tb and U tc Respectively represent the three-phase modulation signals input to the SPWM modulation module; ω n K is the rated frequency of the input voltage on the AC side of the rectifier; pc and K ic They represent the proportional gain and integral gain of the current inner loop control respectively.

8. A rectifier starting control system considering the inertia transfer link, characterized in that: Applying the method according to any one of claims 1 to 7, comprising: The acquisition and processing module is used to collect the rectifier grid connection point voltage V pcc and the rectifier grid-connected point input current I g , and based on the phase-locked loop control, the rectifier grid-connected point voltage V pcc The projection value V on the dq axis of the rectifier phase-locked loop control pccd 、V pccq And the projection of the rectifier grid-connected point input current on the dq axis of the rectifier grid-connected point I gd , I gq ; The first processing module is used to detect the projection value V of the rectifier AC side input voltage on the rectifier phase-locked loop control q axis. pccq Less than a given threshold ε q , enable the rectifier start flag S C ; The second processing module is used to bypass the rectifier AC side pre-charging resistor R after a delay of Δt1 S_AC , bypass the pre-charge resistor on the AC side of the rectifier to put the rectifier into uncontrolled rectification mode, and calculate the rectifier output DC voltage V dc ; The third processing module is used to detect the bypass flag S of the pre-charging resistor on the AC side of the rectifier C_AC After a delay of Δt2, the rectifier DC side pre-charge resistor bypass flag S is enabled. C_DC , bypass rectifier DC side pre-charge resistor R S_DC ; The fourth processing module detects that the rectifier AC side pre-charging resistor and the rectifier DC side pre-charging resistor are both bypassed, and then starts the PWM pulse flag S after a delay of Δt3. P , and enable the current inner loop control at the same time, enable the d-axis current reference value I of the current inner loop control dref It increases linearly from 0 and eventually reaches saturation; The fifth processing module detects the actual value of the rectifier DC voltage V dc With reference value V dcref The deviation is less than the given threshold ε dc , enable inertia transfer control flag S I , according to the current output by the inertia transfer control, adjust the d-axis current reference value I of the current inner loop control dref , the d-axis current reference value I of the current inner loop control adjusted after considering inertia transfer is obtained dref '; The sixth processing module is used to adjust the d-axis current reference value I of the current inner loop control after considering the inertia transfer dref 'Input current inner loop control, according to the rectifier grid voltage V pcc The projection value V on the dq axis of the rectifier phase-locked loop control pccd 、V pccq And the rectifier grid-connected point input current I g Projection I on the dq axis of the rectifier grid connection point gd , I gq The PWM control signal is generated to control the operating state of the rectifier.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the rectifier startup control method considering the inertia transfer link according to any one of claims 1 to 7.

10. A processor, characterized in that: The processor is used to run a program, wherein the program, when running, executes the rectifier startup control method considering the inertia transfer link according to any one of claims 1 to 7.

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