A method and device for additional damping control of a doubly-fed wind turbine controller

Abstract

The application provides a doubly-fed wind turbine controller additional damping control method and device, determines a doubly-fed wind turbine rotor current reference value, determines a pre-set current inner loop damping controller additional oscillation damping control instruction, and determines a doubly-fed wind turbine rotor control instruction; and controls the excitation current of the doubly-fed wind turbine rotor. The application determines the doubly-fed wind turbine rotor control instruction through the current inner loop damping controller additional oscillation damping control instruction, realizes the doubly-fed wind turbine controller additional damping control, the control process is simple, the calculation amount is small, and the damping system oscillation capacity can be provided, thereby improving the anti-interference capacity of the wind power grid-connected system; on the basis of the doubly-fed wind turbine rotor simplified control instruction and the doubly-fed wind turbine rotor control instruction compensation amount, the current inner loop damping controller additional oscillation damping control instruction is added, the equivalent damping of the wind power grid-connected system in the subsynchronous frequency band is increased, and the subsynchronous oscillation of the wind power grid-connected system is effectively inhibited.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of new energy power generation technology, in particular to a double-fed wind turbine controller additional damping control method and device. BACKGROUND

[0002] Double-fed wind turbine (DFIG, Double Fed Induction Generator) is a winding type induction generator, the stator winding of double-fed asynchronous generator is directly connected with the power grid, the rotor winding is connected with the power grid through the frequency converter, the frequency, voltage, amplitude and phase of the rotor winding power supply are automatically adjusted by the frequency converter according to the operation requirements, the unit can realize constant frequency power generation at different speeds to meet the requirements of power load and grid connection. Because of the adoption of AC excitation, the generator and the power system form a flexible connection, that is, the excitation current can be adjusted according to the voltage and current of the power grid and the speed of the generator, and the output voltage of the generator can be accurately adjusted to meet the requirements. The advantages of double-fed wind turbine include: 1. It can control reactive power and decouple active power and reactive power control by independently controlling rotor excitation current. 2. No excitation from the power grid, but from the rotor circuit. 3. It can generate reactive power and transmit it to the stator through the grid-side converter.

[0003] With the continuous expansion of grid-connected wind power, the wind power grid-connected system based on power electronic technology is facing serious oscillation. At present, the main measures for double-fed wind turbine control are based on eigenvalue analysis method and number calculation to determine the input control signal and the additional position of the additional damping controller, which can solve the oscillation problem caused by large-scale wind power grid connection. However, the control process is complicated, the calculation amount is large, and the system cannot provide damping oscillation ability, the stability of wind power grid-connected system is poor, and the anti-interference ability is poor. SUMMARY

[0004] In order to overcome the deficiency of poor anti-interference ability of wind power grid-connected system in the prior art, the present application provides a double-fed wind turbine controller additional damping control method, comprising:

[0005] determining the rotor current reference value of the double-fed wind turbine based on the rotor speed reference value of the double-fed wind turbine and the rotor speed of the double-fed wind turbine;

[0006] determining the additional oscillation damping control instruction of the preset constant current inner loop damping controller based on the rotor current reference value of the double-fed wind turbine;

[0007] determining the rotor control instruction of the double-fed wind turbine based on the additional oscillation damping control instruction and the rotor current of the double-fed wind turbine;

[0008] controlling the excitation current of the rotor of the double-fed wind turbine based on the rotor control instruction of the double-fed wind turbine.

[0009] the setting of the additional damping controller, comprising:

[0010] In the current inner loop control circuit, a filter link and a proportional amplification and amplitude limiting output link are sequentially constructed to obtain the additional damping controller;

[0011] and the damping coefficient of the additional damping controller is determined based on the outer loop proportional coefficient of the active power;

[0012] The filter link is used to filter the steady-state direct current component and the high-frequency component in the input control signal and retain the subsynchronous frequency component; the proportional amplification and amplitude limiting output link is used to obtain the control instruction by proportional amplification and amplitude limiting of the subsynchronous frequency component and then output the control instruction.

[0013] The additional oscillation damping control instruction of the pre-set current inner loop damping controller is determined based on the rotor current reference value of the doubly-fed wind power generator unit, comprising:

[0014] The d-axis rotor current disturbance of the doubly-fed wind power generator unit is obtained by processing the d-axis rotor current reference value of the doubly-fed wind power generator unit through the filter link of the current inner loop damping controller;

[0015] The d-axis current inner loop damping controller additional oscillation damping control instruction is obtained by processing the d-axis rotor current disturbance of the doubly-fed wind power generator unit through the proportional amplification link and the amplitude limiting link of the current inner loop damping controller.

[0016] The d-axis current inner loop damping controller additional oscillation damping control instruction is determined according to the following formula:

[0017]

[0018] wherein, Δu dr is the d-axis current inner loop damping controller additional oscillation damping control instruction, Δu dr_max is the upper limit of the d-axis current inner loop damping controller additional oscillation damping control instruction, Δu dr_min is the lower limit of the d-axis current inner loop damping controller additional oscillation damping control instruction, Δi dr_ref is the d-axis rotor current disturbance of the doubly-fed wind power generator unit, K damp is the damping coefficient of the additional damping controller.

[0019] The determination of the damping coefficient of the additional damping controller, comprising:

[0020] The d-axis stator current and the q-axis stator current of the doubly-fed wind power generator unit are determined based on the d-axis rotor current and the q-axis rotor current of the doubly-fed wind power generator unit;

[0021] The electromagnetic torque variation of the doubly-fed wind power generator unit is determined based on the d-axis stator current and the q-axis stator current of the doubly-fed wind power generator unit;

[0022] determine an additional damping controller damping coefficient based on the electromagnetic torque variation of the doubly-fed wind power generator.

[0023] The doubly-fed wind power generator stator d-axis current and q-axis current are determined according to the following formula:

[0024]

[0025] wherein, i ds is the doubly-fed wind power generator stator d-axis current, i qs is the doubly-fed wind power generator stator q-axis current, i qr is the doubly-fed wind power generator rotor q-axis current, i dr is the doubly-fed wind power generator rotor d-axis current, L m is the mutual inductance between the doubly-fed wind power generator rotor and stator, L s is the doubly-fed wind power generator stator leakage inductance, ω1 is the synchronous angular velocity of the wind power grid-connected system, U s is the doubly-fed wind power generator stator voltage.

[0026] determine the electromagnetic torque variation of the doubly-fed wind power generator based on the doubly-fed wind power generator stator d-axis current and q-axis current, comprising:

[0027] determine the electromagnetic torque of the doubly-fed wind power generator according to the following formula:

[0028]

[0029] wherein, T em is the electromagnetic torque of the doubly-fed wind power generator;

[0030] determine the electromagnetic torque variation of the doubly-fed wind power generator based on the electromagnetic torque of the doubly-fed wind power generator according to the following formula:

[0031]

[0032] wherein, ΔT em is the electromagnetic torque variation of the doubly-fed wind power generator, Δi dr is the doubly-fed wind power generator rotor d-axis current variation.

[0033] determine the additional damping controller damping coefficient according to the following formula:

[0034]

[0035] wherein, K p1 is the active power outer loop proportional coefficient, K p2 is the current inner loop proportional coefficient, ψ s is the doubly-fed wind power generator stator flux linkage.

[0036] The method for determining the rotor control command of a doubly-fed wind turbine based on the additional oscillation damping control command of the current inner loop damping controller and the rotor current of the doubly-fed wind turbine includes:

[0037] Based on the reference value of the d-axis current of the doubly fed wind turbine rotor and the d-axis current of the doubly fed wind turbine rotor, the simplified control command of the d-axis of the doubly fed wind turbine rotor is determined.

[0038] The compensation amount of the control command for the rotor d-axis of the doubly fed wind turbine is determined based on the rotor d-axis current, rotor q-axis current and stator q-axis current of the doubly fed wind turbine.

[0039] The oscillation damping control command of the inner loop damping controller of the d-axis current, the simplified d-axis control command of the doubly-fed wind turbine rotor, and the compensation amount of the d-axis control command of the doubly-fed wind turbine rotor are superimposed to obtain the d-axis control command of the doubly-fed wind turbine rotor.

[0040] The simplified control command for the d-axis of the doubly fed wind turbine rotor is determined by the following formula:

[0041]

[0042] In the formula, u dr1 To simplify the control commands for the d-axis of the doubly-fed wind turbine rotor, i dr K represents the d-axis current of the doubly-fed wind turbine rotor. p2 K is the proportional coefficient of the inner current loop. i2 is the integral coefficient of the inner current loop.

[0043] The compensation amount for the rotor d-axis control command of the doubly fed wind turbine is determined by the following formula:

[0044] u dr2 =R r i dr -L m (ω1-ω r )i qs -L r (ω1-ω r )i qr

[0045] In the formula, u dr2 R is the compensation amount for the d-axis control command of the doubly-fed wind turbine rotor. r L is the rotor resistance of a doubly-fed wind turbine. m For the mutual inductance between the rotor and stator of a doubly-fed wind turbine, ω r i is the rotor angular velocity of the doubly fed wind turbine. qr Let i be the q-axis current of the doubly-fed wind turbine rotor. qs This refers to the stator q-axis current of the doubly fed wind turbine.

[0046] The rotor current reference value of the doubly-fed wind turbine is determined according to the following formula:

[0047]

[0048] In the formula, i dr_ref is the rotor d-axis current reference value of the doubly-fed wind turbine, ω r_ref is the rotor speed reference value of the doubly-fed wind turbine, L s is the stator leakage inductance of the doubly-fed wind turbine, K i1 is the integral coefficient of the active power outer loop, K p1 is the proportional coefficient of the active power outer loop.

[0049] In another aspect, the application further provides a doubly-fed wind turbine controller additional damping control device, comprising:

[0050] A first determining module is configured to determine the rotor current reference value of the doubly-fed wind turbine based on the rotor speed reference value of the doubly-fed wind turbine and the rotor speed of the doubly-fed wind turbine;

[0051] A second determining module is configured to determine the additional oscillation damping control instruction of the preset current inner loop damping controller based on the rotor current reference value of the doubly-fed wind turbine;

[0052] A third determining module is configured to determine the rotor control instruction of the doubly-fed wind turbine based on the additional oscillation damping control instruction of the current inner loop damping controller and the rotor current of the doubly-fed wind turbine;

[0053] A control module is configured to control the field current of the rotor of the doubly-fed wind turbine based on the rotor control instruction of the doubly-fed wind turbine.

[0054] The second determining module is specifically configured to:

[0055] In the current inner loop control circuit, a filter link and a proportional amplification and amplitude limiting output link are sequentially constructed to obtain the additional damping controller;

[0056] The damping coefficient of the additional damping controller is determined based on the proportional coefficient of the active power outer loop;

[0057] The filter link is configured to filter the steady-state DC component and the high-frequency component in the input control signal and retain the subsynchronous frequency component; the proportional amplification and amplitude limiting output link is configured to proportionally amplify and limit the subsynchronous frequency component to obtain the control instruction and output the control instruction.

[0058] The third determining module is specifically configured to:

[0059] The rotor d-axis current reference value of the doubly-fed wind turbine is processed through the filter link of the current inner loop damping controller to obtain the rotor d-axis current disturbance of the doubly-fed wind turbine;

[0060] The d-axis rotor current disturbance of the doubly-fed wind turbine is processed through a proportional amplification link and a limiting link of the current inner loop damping controller, and a d-axis current inner loop damping controller additional oscillation damping control instruction is obtained.

[0061] The technical solution provided by the application has the following beneficial effects:

[0062] In the additional damping control method of the doubly-fed wind turbine controller provided by the application, the rotor current reference value of the doubly-fed wind turbine is determined based on the rotor speed reference value and the rotor speed of the doubly-fed wind turbine; the additional oscillation damping control instruction of the pre-set current inner loop damping controller is determined based on the rotor current reference value of the doubly-fed wind turbine; the rotor control instruction of the doubly-fed wind turbine is determined based on the additional oscillation damping control instruction and the rotor current of the doubly-fed wind turbine; and the field current of the rotor of the doubly-fed wind turbine is controlled based on the rotor control instruction of the doubly-fed wind turbine. The rotor control instruction of the doubly-fed wind turbine is determined through the additional oscillation damping control instruction of the current inner loop damping controller, the additional damping control of the doubly-fed wind turbine controller is realized, the control process is simple, the calculation amount is small, the ability of damping system oscillation can be provided, and the anti-interference ability of the wind power grid-connected system is improved.

[0063] The rotor current reference value of the doubly-fed wind turbine is determined based on the rotor speed reference value and the rotor speed of the doubly-fed wind turbine, and the additional oscillation damping control instruction of the current inner loop damping controller is determined based on the obtained rotor current reference value of the doubly-fed wind turbine, thereby providing a basis for the control of the field current of the rotor of the doubly-fed wind turbine.

[0064] The technical solution provided by the application increases the additional oscillation damping control instruction of the current inner loop damping controller on the basis of the simplified rotor control instruction of the doubly-fed wind turbine and the compensation amount of the rotor control instruction of the doubly-fed wind turbine, increases the equivalent damping of the wind power grid-connected system in the subsynchronous frequency band, and effectively suppresses the subsynchronous oscillation of the wind power grid-connected system. BRIEF DESCRIPTION OF DRAWINGS

[0065] Figure 1 It is a flow chart of the additional damping control method of the doubly-fed wind turbine controller in the embodiment of the application.

[0066] Figure 2 It is a flow chart of the determination of the additional oscillation damping control instruction of the d-axis current inner loop damping controller in the embodiment of the application.

[0067] Figure 3 It is a block diagram of the determination of the d-axis rotor control instruction of the doubly-fed wind turbine in the embodiment of the application.

[0068] Figure 4 It is a flow chart of the determination of the d-axis rotor current reference value of the doubly-fed wind turbine in the embodiment of the application.

[0069] Figure 5 is a flow chart for determining d-axis control instruction of a rotor of a doubly-fed wind turbine in an embodiment of the application;

[0070] Figure 6 is a flow chart for determining q-axis control instruction of a rotor of a doubly-fed wind turbine in an embodiment of the application. DETAILED DESCRIPTION

[0071] The application will be further described in detail below with reference to the accompanying drawings.

[0072] Embodiment 1

[0073] Embodiment 1 of the application provides a method for additional damping control of a doubly-fed wind turbine controller, and a specific flow chart is shown in Figure 1 and the specific process is as follows:

[0074] S101: determining a rotor current reference value of the doubly-fed wind turbine based on a rotor speed reference value of the doubly-fed wind turbine and a rotor speed of the doubly-fed wind turbine;

[0075] S102: determining an additional oscillation damping control instruction of a current inner loop damping controller based on the rotor current reference value of the doubly-fed wind turbine;

[0076] S103: determining a rotor control instruction of the doubly-fed wind turbine based on the additional oscillation damping control instruction and the rotor current of the doubly-fed wind turbine, and a specific process is shown in Figure 5 ;

[0077] S104: controlling an excitation current of the rotor of the doubly-fed wind turbine based on the rotor control instruction of the doubly-fed wind turbine.

[0078] In the above S102, the setting of the additional damping controller includes:

[0079] In the current inner loop control circuit, a filter link and a proportional amplification and amplitude limiting output link are sequentially constructed to obtain the additional damping controller;

[0080] and a damping coefficient of the additional damping controller is determined based on a proportional coefficient of an active power outer loop;

[0081] The filter link is used to filter the steady direct current component and high frequency component in the input control signal and retain the subsynchronous frequency component; the proportional amplification and amplitude limiting output link is used to proportionally amplify and limit the amplitude of the subsynchronous frequency component to obtain the control instruction and output.

[0082] Determining the rotor control instruction of the doubly-fed wind turbine based on the additional oscillation damping control instruction and the rotor current of the doubly-fed wind turbine, as shown in Figure 2 , includes:

[0083] The d-axis rotor current reference value of the doubly-fed wind turbine is processed by a filter link of the current inner loop damping controller to obtain a d-axis rotor current disturbance of the doubly-fed wind turbine;

[0084] The d-axis rotor current disturbance of the doubly-fed wind turbine is processed by a proportional amplification link and a limiting link of the current inner loop damping controller to obtain an oscillation damping control instruction of the d-axis current inner loop damping controller.

[0085] Since the d-axis rotor current i dr of the doubly-fed wind turbine is controlled by the rotor-side converter of the doubly-fed wind turbine, the d-axis rotor current i qr of the doubly-fed wind turbine is controlled by the rotor-side converter of the doubly-fed wind turbine. dr_ref The d-axis rotor current reference value i qr_ref and the q-axis rotor current reference value i qr_ref of the doubly-fed wind turbine are tracked respectively, and the subsynchronous frequency component of the rotor current reference value of the doubly-fed wind turbine is amplified after the current inner loop. Figure 6 As shown in FIG. 4, the d-axis rotor current i qr_ref is mainly obtained by two integral links without a proportional amplification link, so the subsynchronous frequency component of the d-axis rotor current i dr_ref is small; and the proportional amplification link exists in the active power outer loop, so the subsynchronous frequency component of the d-axis rotor current i dr_ref is large, and the d-axis rotor current i dr_ref dominates. Therefore, the d-axis rotor current i dr_ref is taken as an input signal of the additional damping controller, and the subsynchronous frequency component of the d-axis rotor current i dr is proportionally amplified and added to the d-axis voltage reference value of the doubly-fed wind turbine, and the principle can be understood as follows: in the subsynchronous oscillation mode, a virtual negative resistance is added to the rotor circuit, and the virtual negative resistance presents a positive value on the stator side of the doubly-fed wind turbine after considering the rotor slip at the subsynchronous frequency, so that the equivalent total resistance of the wind power grid-connected system is increased.

[0086] The oscillation damping control instruction of the d-axis current inner loop damping controller is determined according to the following formula:

[0087]

[0088] wherein, Δu dr is the oscillation damping control instruction of the d-axis current inner loop damping controller, Δu dr_max is the upper limit of the oscillation damping control instruction of the d-axis current inner loop damping controller, Δu dr_min is the lower limit of the oscillation damping control instruction of the d-axis current inner loop damping controller, Δi dr_ref is the d-axis rotor current disturbance of the doubly-fed wind turbine, and K damp is a damping coefficient of the additional damping controller.

[0089] The determination of the additional damping controller damping coefficient comprises:

[0090] The d-axis current and the q-axis current of the stator of the doubly-fed wind power generator are determined based on the d-axis current and the q-axis current of the rotor of the doubly-fed wind power generator.

[0091] The electromagnetic torque variation of the doubly-fed wind power generator is determined based on the d-axis current and the q-axis current of the stator of the doubly-fed wind power generator.

[0092] The additional damping controller damping coefficient is determined based on the electromagnetic torque variation of the doubly-fed wind power generator.

[0093] The d-axis current and the q-axis current of the stator of the doubly-fed wind power generator are determined according to the following formula:

[0094]

[0095] In the formula, i ds is the d-axis current of the stator of the doubly-fed wind power generator, i qs is the q-axis current of the stator of the doubly-fed wind power generator, i qr is the q-axis current of the rotor of the doubly-fed wind power generator, i dr is the d-axis current of the rotor of the doubly-fed wind power generator, L m is the mutual inductance between the rotor and the stator of the doubly-fed wind power generator, L s is the leakage inductance of the stator of the doubly-fed wind power generator, ω1 is the synchronous angular velocity of the wind power grid-connected system, U s is the stator voltage of the doubly-fed wind power generator.

[0096] The electromagnetic torque variation of the doubly-fed wind power generator is determined based on the d-axis current and the q-axis current of the stator of the doubly-fed wind power generator, and the determination comprises:

[0097] The electromagnetic torque of the doubly-fed wind power generator is determined according to the following formula:

[0098]

[0099] In the formula, T em is the electromagnetic torque of the doubly-fed wind power generator;

[0100] The electromagnetic torque variation of the doubly-fed wind power generator is determined based on the electromagnetic torque of the doubly-fed wind power generator according to the following formula:

[0101]

[0102] In the formula, ΔT em is the electromagnetic torque variation of the doubly-fed wind power generator, Δi dr is the d-axis current variation of the rotor of the doubly-fed wind power generator.

[0103] The additional damping controller damping coefficient is determined according to the following formula:

[0104]

[0105] wherein K p1 is a proportional coefficient of the active power outer loop, K p2 is a proportional coefficient of the current inner loop, ω1is a synchronous angular velocity of the wind power grid-connected system, U s is a stator voltage of the doubly-fed wind power generator set, ψ s is a stator flux linkage of the doubly-fed wind power generator set.

[0106] The rotor control command of the doubly-fed wind power generator set is determined based on the oscillation damping control command added to the current inner loop damping controller and the rotor current of the doubly-fed wind power generator set, as shown in the following formula: Figure 3

[0107] The d-axis simplified control command of the doubly-fed wind power generator set is determined based on the d-axis current reference value of the rotor of the doubly-fed wind power generator set and the d-axis current of the rotor of the doubly-fed wind power generator set.

[0108] The d-axis control command compensation of the rotor of the doubly-fed wind power generator set is determined based on the d-axis current of the rotor of the doubly-fed wind power generator set, the q-axis current of the rotor of the doubly-fed wind power generator set and the q-axis current of the stator of the doubly-fed wind power generator set.

[0109] The d-axis control command of the rotor of the doubly-fed wind power generator set is obtained by superimposing the oscillation damping control command added to the d-axis current inner loop damping controller, the d-axis simplified control command of the rotor of the doubly-fed wind power generator set and the d-axis control command compensation of the rotor of the doubly-fed wind power generator set.

[0110] The d-axis simplified control command of the rotor of the doubly-fed wind power generator set is determined according to the following formula:

[0111]

[0112] wherein u dr1 is the d-axis simplified control command of the rotor of the doubly-fed wind power generator set, i dr is the d-axis current of the rotor of the doubly-fed wind power generator set, K p2 is a proportional coefficient of the current inner loop, K i2 is an integral coefficient of the current inner loop.

[0113] The d-axis control command compensation of the rotor of the doubly-fed wind power generator set is determined according to the following formula:

[0114] u dr2 = R r i dr - L m (ω1- ω r )i qs - L r (ω1- ω r )i qr

[0115] wherein u dr2 ​R is the compensation amount for the d-axis control command of the doubly-fed wind turbine rotor. r L is the rotor resistance of a doubly-fed wind turbine. m For the mutual inductance between the rotor and stator of a doubly-fed wind turbine, ω r i is the rotor angular velocity of the doubly fed wind turbine. qr Let i be the q-axis current of the doubly-fed wind turbine rotor. qs This refers to the stator q-axis current of the doubly fed wind turbine.

[0116] like Figure 4 As shown, the reference value of the rotor current of the doubly-fed wind turbine is determined by the following formula:

[0117]

[0118] In the formula, i dr_ref ω is the reference value for the d-axis current of the doubly-fed wind turbine rotor. r_ref L is the reference value for the rotor speed of a doubly-fed wind turbine. s For the stator leakage inductance of the doubly fed wind turbine, K i1 K is the integral coefficient of the active power outer loop. p1 This is the proportional coefficient of the active power outer loop.

[0119] In Embodiment 1 of this invention, the subscript d represents the d-axis component, q represents the q-axis component, the subscript s represents the stator of the doubly fed wind turbine, r represents the rotor of the doubly fed wind turbine, and i represents the current.

[0120] Example 2

[0121] Based on the same inventive concept, Embodiment 2 of the present invention also provides an additional damping control device for a doubly fed wind turbine controller, comprising:

[0122] The first determining module is used to determine the reference value of the rotor current of the doubly fed wind turbine based on the reference value of the rotor speed of the doubly fed wind turbine and the rotor speed of the doubly fed wind turbine.

[0123] The second determining module is used to determine the additional oscillation damping control command of the pre-set current inner loop damping controller based on the rotor current reference value of the doubly fed wind turbine.

[0124] The third determining module is used to determine the rotor control command of the doubly fed wind turbine based on the additional oscillation damping control command and the rotor current of the doubly fed wind turbine.

[0125] The control module is used to control the excitation current of the doubly-fed wind turbine rotor based on the rotor control commands of the doubly-fed wind turbine.

[0126] The second determining module is specifically used for:

[0127] In the current inner loop control circuit, a filter stage, a proportional amplifier, and a limiting output stage are constructed sequentially to obtain an additional damping controller.

[0128] The damping coefficient of the additional damping controller is determined based on the active power outer loop proportional coefficient.

[0129] The filtering stage filters the steady-state DC component and high-frequency component in the input control signal, retaining the subsynchronous frequency component; the proportional amplification and limiting output stage amplifies and limits the subsynchronous frequency component to obtain the control command and outputs it.

[0130] The second determining module is specifically used for:

[0131] The reference value of the rotor d-axis current of the doubly fed wind turbine is processed by the filtering stage of the current inner loop damping controller to obtain the rotor d-axis current disturbance of the doubly fed wind turbine.

[0132] The d-axis current disturbance of the doubly fed wind turbine rotor is processed by the proportional amplification and limiting stages of the current inner loop damping controller to obtain the additional oscillation damping control command of the d-axis current inner loop damping controller.

[0133] Due to the control of the rotor-side converter of the doubly-fed wind turbine, the rotor d-axis current i of the doubly-fed wind turbine is... dr and the rotor q-axis current i of the doubly fed wind turbine qr The reference value of the rotor d-axis current i of the doubly fed wind turbine should be tracked separately. dr_ref Reference value of rotor q-axis current i of doubly fed wind turbine qr_ref The change in frequency, after passing through the inner current loop, will amplify the subsynchronous frequency component in the rotor current reference value of the doubly-fed wind turbine. For example... Figure 6 As shown, i qr_ref It is mainly obtained from reactive power through two integral stages, without going through a proportional amplification stage, so i qr_ref The subsynchronous frequency component is relatively small; however, there is a proportional amplification stage in the active power outer loop, therefore i dr_ref The subsynchronous frequency component is relatively large, i dr_ref It has a dominant influence. Therefore, we choose i. dr_ref As the input signal to the additional damping controller, by i dr_ref The subsynchronous frequency component is amplified proportionally and added to the reference value of the rotor d-axis voltage of the doubly-fed wind turbine. The principle can be understood as follows: In the subsynchronous oscillation mode, a virtual negative resistance is added to the rotor circuit. After considering the rotor slip at the subsynchronous frequency, the virtual negative resistance presents a positive value on the stator side of the doubly-fed wind turbine, thereby increasing the equivalent total resistance of the wind power grid-connected system.

[0134] The second determining module determines the d-axis current inner loop damping controller additional oscillation damping control instruction according to the following formula:

[0135]

[0136] wherein, Δu dr is the d-axis current inner loop damping controller additional oscillation damping control instruction, Δu dr_max is the upper limit of the d-axis current inner loop damping controller additional oscillation damping control instruction, Δu dr_min is the lower limit of the d-axis current inner loop damping controller additional oscillation damping control instruction, Δi dr_ref is the rotor d-axis current disturbance of the doubly-fed wind power generator, K damp is the damping coefficient of the additional damping controller.

[0137] The specific process of the second determining module determining the damping coefficient of the additional damping controller is as follows:

[0138] determining the stator d-axis current and the stator q-axis current of the doubly-fed wind power generator based on the rotor d-axis current and the rotor q-axis current of the doubly-fed wind power generator;

[0139] determining the electromagnetic torque variation of the doubly-fed wind power generator based on the stator d-axis current and the stator q-axis current of the doubly-fed wind power generator;

[0140] determining the damping coefficient of the additional damping controller based on the electromagnetic torque variation of the doubly-fed wind power generator.

[0141] The second determining module determines the stator d-axis current and the stator q-axis current of the doubly-fed wind power generator according to the following formula:

[0142]

[0143] wherein, i ds is the stator d-axis current of the doubly-fed wind power generator, i qs is the stator q-axis current of the doubly-fed wind power generator, i qr is the rotor q-axis current of the doubly-fed wind power generator, i dr is the rotor d-axis current of the doubly-fed wind power generator, L m is the mutual inductance between the rotor and the stator of the doubly-fed wind power generator, L s is the stator leakage inductance of the doubly-fed wind power generator, ω1 is the synchronous angular velocity of the wind power grid-connected system, U s is the stator voltage of the doubly-fed wind power generator.

[0144] The second determining module determines the electromagnetic torque variation of the doubly-fed wind power generator based on the stator d-axis current and the stator q-axis current of the doubly-fed wind power generator, and the specific process is as follows:

[0145] determining the electromagnetic torque of the doubly-fed wind power generator according to the following formula:

[0146]

[0147] In the formula, T em is the electromagnetic torque of the doubly-fed wind turbine;

[0148] Based on the electromagnetic torque of the doubly-fed wind turbine, the electromagnetic torque variation of the doubly-fed wind turbine is determined according to the following formula:

[0149]

[0150] In the formula, ΔT em is the electromagnetic torque variation of the doubly-fed wind turbine, Δi dr is the rotor d-axis current variation of the doubly-fed wind turbine.

[0151] The second determining module determines the additional damping controller damping coefficient according to the following formula:

[0152]

[0153] In the formula, K p1 is the active power outer loop proportional coefficient, K p2 is the current inner loop proportional coefficient, ω1 is the synchronous angular velocity of the wind power grid-connected system, U s is the stator voltage of the doubly-fed wind turbine, ψ s is the stator flux linkage of the doubly-fed wind turbine.

[0154] The third determining module determines the rotor control instruction of the doubly-fed wind turbine based on the additional oscillation damping control instruction of the current inner loop damping controller and the rotor current of the doubly-fed wind turbine, and the specific process is as follows:

[0155] The rotor d-axis simplified control instruction of the doubly-fed wind turbine is determined based on the rotor d-axis current reference value of the doubly-fed wind turbine and the rotor d-axis current of the doubly-fed wind turbine;

[0156] The rotor d-axis control instruction compensation of the doubly-fed wind turbine is determined based on the rotor d-axis current of the doubly-fed wind turbine, the rotor q-axis current of the doubly-fed wind turbine and the stator q-axis current of the doubly-fed wind turbine;

[0157] The rotor d-axis control instruction of the doubly-fed wind turbine is obtained by superimposing the additional oscillation damping control instruction of the d-axis current inner loop damping controller, the rotor d-axis simplified control instruction of the doubly-fed wind turbine and the rotor d-axis control instruction compensation of the doubly-fed wind turbine.

[0158] The third determining module determines the rotor d-axis simplified control instruction of the doubly-fed wind turbine according to the following formula:

[0159]

[0160] In the formula, u dr1 is the rotor d-axis simplified control instruction of the doubly-fed wind turbine, idr K is the proportional coefficient of the current inner loop p2 K is the proportional coefficient of the current inner loop i2 K is the integral coefficient of the current inner loop.

[0161] The d-axis control instruction compensation of the doubly-fed wind turbine rotor is determined according to the following formula:

[0162] u dr2 = R r i dr -L m (ω1-ω r )i qs -L r (ω1-ω r )i qr

[0163] In the formula, u dr2 is the d-axis control instruction compensation of the doubly-fed wind turbine rotor, R r is the rotor resistance of the doubly-fed wind turbine, L m is the mutual inductance between the rotor and the stator of the doubly-fed wind turbine, ω r is the rotor angular velocity of the doubly-fed wind turbine, i qr is the q-axis current of the doubly-fed wind turbine rotor, and i qs is the q-axis current of the stator of the doubly-fed wind turbine.

[0164] The first determining module determines the rotor current reference value of the doubly-fed wind turbine according to the following formula:

[0165]

[0166] In the formula, i dr_ref is the d-axis current reference value of the doubly-fed wind turbine rotor, ω r_ref is the rotor speed reference value of the doubly-fed wind turbine, L s is the leakage inductance of the stator of the doubly-fed wind turbine, K i1 is the integral coefficient of the active power outer loop, K p1 is the proportional coefficient of the active power outer loop.

[0167] In Embodiment 2 of the application, the subscript d represents the d-axis component, the subscript q represents the q-axis component, the subscript s represents the stator of the doubly-fed wind turbine, the subscript r represents the rotor of the doubly-fed wind turbine, and i is current.

[0168] For the convenience of description, each part of the device is described as various modules or units in function. Of course, the functions of the modules or units can be realized in the same or multiple software or hardware in the implementation of the application.

[0169] Those skilled in the art will appreciate that embodiments of the application can be devised for a method, a system, or a computer program product. Accordingly, the present application can be embodied in the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application can take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, etc.) embodying computer readable program code.

[0170] The present application is described in reference to the flowchart illustrations and / or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams.

[0171] These computer program instructions can also be stored in a computer- readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams.

[0172] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams.

[0173] Finally, it should be noted that the above-mentioned embodiments are merely intended for describing the technical solutions of the present application, but not for limiting the same. According to the above-mentioned embodiments, the ordinary skilled in the art can still modify or equivalently replace the specific embodiments of the present application, and any modification or equivalent replacement without departing from the spirit and scope of the present application shall be included in the protection scope of the patent application to be granted of the present application.

Claims

1. A method for additional damping control of a doubly-fed wind turbine controller, characterized in that, include: The reference value of the rotor current of the doubly fed wind turbine is determined based on the reference value of the rotor speed and the rotor speed of the doubly fed wind turbine. Based on the reference value of the rotor current of the doubly fed wind turbine, the additional oscillation damping control command of the pre-set inner loop damping controller is determined. The rotor control command of the doubly fed wind turbine is determined based on the additional oscillation damping control command and the rotor current of the doubly fed wind turbine. The excitation current of the doubly fed wind turbine rotor is controlled based on the rotor control command of the doubly fed wind turbine. The settings for the current inner loop damping controller include: In the current inner loop control circuit, a filter stage, a proportional amplifier, and a limiting output stage are constructed sequentially to obtain an additional damping controller. The damping coefficient of the inner current loop damping controller is determined based on the active power outer loop proportional coefficient. The filtering stage is used to filter the steady-state DC component and high-frequency component in the input control signal, while retaining the subsynchronous frequency component; the proportional amplification and limiting output stage is used to proportionally amplify and limit the subsynchronous frequency component to obtain the control command and output it. The determination of the damping coefficient of the inner current loop damping controller includes: The stator d-axis current and q-axis current of the doubly fed wind turbine are determined based on the rotor d-axis current and q-axis current of the doubly fed wind turbine. The electromagnetic torque variation of the doubly fed wind turbine is determined based on the stator d-axis current and q-axis current of the doubly fed wind turbine. The damping coefficient of the additional damping controller is determined based on the electromagnetic torque variation of the doubly fed wind turbine. The damping coefficient of the additional damping controller is determined by the following formula: In the formula, K p1 K is the active power outer loop proportional coefficient. p2 The inner loop proportionality coefficient, ψ s U is the stator flux linkage of the doubly-fed wind turbine, ω1 is the synchronous angular velocity of the wind power grid-connected system, and U s This refers to the stator voltage of the doubly fed wind turbine.

2. The additional damping control method for a doubly-fed wind turbine controller according to claim 1, characterized in that, The additional oscillation damping control command for the pre-set inner loop damping controller, determined based on the rotor current reference value of the doubly fed wind turbine, includes: The reference value of the rotor d-axis current of the doubly fed wind turbine is processed by the filtering stage of the current inner loop damping controller to obtain the rotor d-axis current disturbance of the doubly fed wind turbine. The d-axis current disturbance of the doubly fed wind turbine rotor is processed by the proportional amplification and limiting stages of the current inner loop damping controller to obtain the additional oscillation damping control command of the d-axis current inner loop damping controller.

3. The additional damping control method for a doubly-fed wind turbine controller according to claim 2, characterized in that, The additional oscillation damping control command of the d-axis current inner loop damping controller is determined by the following formula: Where, Δu dr Add an oscillation damping control command, Δu, to the d-axis current inner loop damping controller. dr_max Add an upper limit to the oscillation damping control command Δu to the d-axis current inner loop damping controller. dr_min Add a lower limit to the oscillation damping control command Δi to the inner loop damping controller of the d-axis current. dr_ref K represents the d-axis current disturbance of the doubly-fed wind turbine rotor. damp The damping coefficient is the additional damping controller damping coefficient.

4. The additional damping control method for a doubly-fed wind turbine controller according to claim 1, characterized in that, The stator d-axis current and q-axis current of the doubly fed wind turbine are determined by the following formula: In the formula, i ds i is the stator d-axis current of the doubly fed wind turbine. qs i is the stator q-axis current of the doubly fed wind turbine. qr Let i be the q-axis current of the doubly-fed wind turbine rotor. dr L is the rotor d-axis current of the doubly-fed wind turbine. m For the mutual inductance between the rotor and stator of the doubly fed wind turbine, L s U is the stator leakage inductance of the doubly-fed wind turbine, ω1 is the synchronous angular velocity of the wind power grid-connected system, and U is the stator leakage inductance of the doubly-fed wind turbine. s This refers to the stator voltage of the doubly fed wind turbine.

5. The additional damping control method for a doubly-fed wind turbine controller according to claim 4, characterized in that, The determination of the electromagnetic torque variation of the doubly-fed wind turbine based on the stator d-axis current and q-axis current includes: The electromagnetic torque of a doubly-fed wind turbine is determined by the following formula: In the formula, T em The electromagnetic torque of the doubly-fed wind turbine; Based on the electromagnetic torque of the doubly-fed wind turbine, the change in electromagnetic torque of the doubly-fed wind turbine is determined by the following formula: In the formula, ΔT em Δi represents the change in electromagnetic torque of the doubly-fed wind turbine. dr This represents the change in the d-axis current of the doubly-fed wind turbine rotor.

6. The additional damping control method for a doubly-fed wind turbine controller according to claim 1, characterized in that, The determination of the rotor control command for the doubly-fed wind turbine based on the additional oscillation damping control command and the rotor current of the doubly-fed wind turbine includes: Based on the reference value of the d-axis current of the doubly fed wind turbine rotor and the d-axis current of the doubly fed wind turbine rotor, the simplified control command of the d-axis of the doubly fed wind turbine rotor is determined. The compensation amount of the control command for the rotor d-axis of the doubly fed wind turbine is determined based on the rotor d-axis current, rotor q-axis current and stator q-axis current of the doubly fed wind turbine. The oscillation damping control command of the inner loop damping controller of the d-axis current, the simplified d-axis control command of the doubly-fed wind turbine rotor, and the compensation amount of the d-axis control command of the doubly-fed wind turbine rotor are superimposed to obtain the d-axis control command of the doubly-fed wind turbine rotor.

7. The additional damping control method for a doubly-fed wind turbine controller according to claim 6, characterized in that, The simplified control command for the rotor d-axis of the doubly fed wind turbine is determined by the following formula: In the formula, u dr1 To simplify the control commands for the d-axis of the doubly-fed wind turbine rotor, i dr K represents the d-axis current of the doubly-fed wind turbine rotor. p2 K is the proportional coefficient of the inner current loop. i2 i is the integral coefficient of the inner current loop. dr_ref This is the reference value for the d-axis current of the rotor of a doubly fed wind turbine.

8. The additional damping control method for a doubly-fed wind turbine controller according to claim 7, characterized in that, The compensation amount for the rotor d-axis control command of the doubly fed wind turbine is determined by the following formula: at dr2 =R r and dr -L m (ω1-ω r )and qs -L r (ω1-ω r )and qr In the formula, u dr2 R is the compensation amount for the d-axis control command of the doubly-fed wind turbine rotor. r L is the rotor resistance of a doubly-fed wind turbine. m For the mutual inductance between the rotor and stator of a doubly-fed wind turbine, ω r i is the rotor angular velocity of the doubly fed wind turbine. qr Let i be the q-axis current of the doubly-fed wind turbine rotor. qs This refers to the stator q-axis current of the doubly fed wind turbine.

9. The additional damping control method for a doubly-fed wind turbine controller according to claim 8, characterized in that, The reference value of the rotor current of the doubly fed wind turbine is determined by the following formula: In the formula, i dr_ref ω is the reference value for the d-axis current of the doubly-fed wind turbine rotor. r_ref K is the reference value for the rotor speed of a doubly-fed wind turbine. i1 L is the integral coefficient of the active power outer loop. s This refers to the stator leakage inductance of a doubly fed wind turbine.

10. A damping control device for a doubly-fed wind turbine controller, characterized in that, include: The first determining module is used to determine the reference value of the rotor current of the doubly fed wind turbine based on the reference value of the rotor speed of the doubly fed wind turbine and the rotor speed of the doubly fed wind turbine. The second determining module is used to determine the additional oscillation damping control command of the pre-set current inner loop damping controller based on the reference value of the rotor current of the doubly fed wind turbine. The third determining module is used to determine the rotor control command of the doubly fed wind turbine based on the additional oscillation damping control command and the rotor current of the doubly fed wind turbine. The control module is used to control the excitation current of the doubly fed wind turbine rotor based on the rotor control command of the doubly fed wind turbine. The second determining module is specifically used for: In the current inner loop control circuit, a filter stage, a proportional amplifier, and a limiting output stage are constructed sequentially to obtain an additional damping controller. The damping coefficient of the additional damping controller is determined based on the active power outer loop proportional coefficient. The filtering stage is used to filter the steady-state DC component and high-frequency component in the input control signal, while retaining the subsynchronous frequency component; the proportional amplification and limiting output stage is used to proportionally amplify and limit the subsynchronous frequency component to obtain the control command and output it. The determination of the damping coefficient of the inner current loop damping controller specifically includes: The stator d-axis current and q-axis current of the doubly fed wind turbine are determined based on the rotor d-axis current and q-axis current of the doubly fed wind turbine. The electromagnetic torque variation of the doubly fed wind turbine is determined based on the stator d-axis current and q-axis current of the doubly fed wind turbine. The damping coefficient of the additional damping controller is determined based on the electromagnetic torque variation of the doubly fed wind turbine. The damping coefficient of the additional damping controller is determined by the following formula: In the formula, K p1 K is the active power outer loop proportional coefficient. p2 The inner loop proportionality coefficient, ψ s U is the stator flux linkage of the doubly-fed wind turbine, ω1 is the synchronous angular velocity of the wind power grid-connected system, and U s This refers to the stator voltage of the doubly fed wind turbine.

11. The additional damping control device for the doubly fed wind turbine controller according to claim 10, characterized in that, The third determining module is specifically used for: The reference value of the rotor d-axis current of the doubly fed wind turbine is processed by the filtering stage of the current inner loop damping controller to obtain the rotor d-axis current disturbance of the doubly fed wind turbine. The d-axis current disturbance of the doubly fed wind turbine rotor is processed by the proportional amplification and limiting stages of the current inner loop damping controller to obtain the additional oscillation damping control command of the d-axis current inner loop damping controller.

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