A high-inertia doubly-fed motor unit and a control method thereof

Abstract

The application provides a high-inertia double-fed motor unit and a control method thereof. The corresponding control method comprises the following steps: when an alternating current system in which the high-inertia double-fed motor unit is located is in a normal operation state, determining a first active instruction value of a rotor side converter according to a pre-set rotating speed instruction value of a double-fed motor; when the alternating current system is in a fault operation state, determining a second active instruction value of the rotor side converter according to a rated power of the double-fed motor; when the alternating current system is switched from the fault operation state to the normal operation state, determining a third active instruction value of the rotor side converter according to a current rotating speed of the rotor of the double-fed motor. The application relies on the double-fed motor with a high rotating inertia rotor to reserve high rotor kinetic energy, and provides active frequency support for the system by releasing the rotor kinetic energy when the system fails.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of generator control, in particular to a double high-inertia double-fed motor unit and a control method thereof. BACKGROUND

[0002] With the continuous expansion of new energy power generation scale and the rapid increase of wind and light generator installed capacity proportion, the problems of short-circuit capacity reduction, system inertia and active frequency stability reduction, insufficient dynamic reactive power support and voltage out-of-limit risk increase caused by large-scale new energy grid connection are increasingly prominent, which brings severe challenges to the safe and stable operation of power system.

[0003] In terms of providing frequency support and improving system frequency stability, due to the gradual reduction of the proportion of traditional thermal power units in the power system, the potential of relying on thermal power units to provide active frequency regulation is limited; the method of relying on wind power units and photovoltaic power generation and other new energy power sources to provide frequency support for the system has technical and economic limitations such as complex control principle and implementation method, poor economy, and narrow adjustable range. SUMMARY

[0004] The high-inertia double-fed motor unit and the control method thereof provided by the present application aim to solve the problems of short-circuit capacity reduction, system inertia and active frequency stability reduction, insufficient dynamic reactive power support and voltage out-of-limit risk increase caused by new energy grid connection in the prior art.

[0005] In order to achieve the above-mentioned purpose, in a first aspect, the present application provides a high-inertia double-fed motor unit, comprising:

[0006] A high-rotational-inertia rotor connected with a rotor of the double-fed motor;

[0007] A rotor-side converter connected with the rotor;

[0008] A grid-side converter connected with the rotor-side converter through a DC bus;

[0009] A step-up transformer connected with the grid-side converter and the stator of the double-fed motor respectively.

[0010] In some embodiments of the present application, the high-inertia double-fed motor unit further comprises:

[0011] A DC bus capacitor arranged on the DC bus.

[0012] In some embodiments of the present application, the high-inertia double-fed motor unit further comprises:

[0013] A filter inductor arranged between the grid-side converter and the step-up transformer.

[0014] In a second aspect, the present application provides a control method of the high-inertia double-fed motor unit according to the first aspect, comprising:

[0015] When the AC system in which the high-inertia double-fed motor unit is located is in a normal operation state, determining a first active instruction value of the rotor-side converter according to a pre-set rotation speed instruction value of the double-fed motor;

[0016] When the AC system in which the high-inertia double-fed motor unit is located is in a fault operation state, determining a second active instruction value of the rotor-side converter according to a rated power of the double-fed motor;

[0017] When the AC system is changed from the fault operation state to the normal operation state, determining a third active instruction value of the rotor-side converter according to a current rotation speed of the rotor of the double-fed motor.

[0018] In some embodiments of the present application, after determining the third active instruction value of the rotor-side converter according to the current rotation speed of the rotor of the double-fed motor, the method further comprises:

[0019] When the duration of the fault operation state disappears reaches a pre-set time, determining the first active instruction value according to the pre-set rotation speed instruction value of the double-fed motor.

[0020] In some embodiments of the present application, the determining of the first active instruction value according to the pre-set rotation speed instruction value of the double-fed motor comprises:

[0021] Determining a difference between the pre-set rotation speed instruction value and a first actual rotation speed of the rotor;

[0022] Determining the first active instruction value according to the difference between the pre-set rotation speed instruction value and the first actual rotation speed of the rotor.

[0023] In some embodiments of the present application, the determining of the first active instruction value according to the difference between the pre-set rotation speed instruction value and the first actual rotation speed of the rotor comprises:

[0024] Determining a first active power instruction value of the double-fed motor according to the difference between the pre-set rotation speed instruction value and the first actual rotation speed of the rotor;

[0025] Determining the first active instruction value according to the first active power instruction value.

[0026] In some embodiments of the present application, the determining of the second active instruction value of the rotor-side converter according to the rated power of the double-fed motor comprises:

[0027] Determining a second active power instruction value of the double-fed motor according to the rated power;

[0028] determining the second active power instruction value according to the second active power instruction value.

[0029] In some embodiments of the application, determining the third active instruction value of the rotor-side converter according to the current rotational speed of the rotor of the double-fed motor comprises:

[0030] performing sample-and-hold processing on the current rotational speed to determine a sample-and-hold rotational speed instruction value;

[0031] determining a difference between the second actual rotational speed and the sample-and-hold rotational speed instruction value;

[0032] determining the third active instruction value according to the difference between the second actual rotational speed and the sample-and-hold rotational speed instruction value.

[0033] In some embodiments of the application, determining the third active instruction value according to the difference between the second actual rotational speed and the sample-and-hold rotational speed instruction value comprises:

[0034] determining a third active power instruction value of the double-fed motor according to the difference between the second actual rotational speed and the sample-and-hold rotational speed instruction value;

[0035] determining the third active instruction value according to the third active power instruction value.

[0036] In a third aspect, the application provides a control device of a high-inertia double-fed motor unit as described in the first aspect, comprising:

[0037] a first active instruction value determination module configured to determine a first active instruction value of a rotor-side converter according to a pre-set rotational speed instruction value of a double-fed motor when an AC system in which the high-inertia double-fed motor unit is located is in a normal operating state;

[0038] a second active instruction value determination module configured to determine a second active instruction value of the rotor-side converter according to a rated power of the double-fed motor when the AC system in which the high-inertia double-fed motor unit is located is in a fault operating state;

[0039] a third active instruction value determination module configured to determine a third active instruction value of the rotor-side converter according to a current rotational speed of a rotor of the double-fed motor when the AC system is switched from the fault operating state to the normal operating state.

[0040] In some embodiments of the application, a control device of a high-inertia double-fed motor unit further comprises:

[0041] a state cycle module configured to determine the first active instruction value according to the pre-set rotational speed instruction value of the double-fed motor when a duration of the fault operating state disappearing reaches a pre-set time.

[0042] In some embodiments of the application, the first active instruction value determination module comprises:

[0043] a difference determination unit configured to determine a difference between the pre-set rotation speed instruction value and the first actual rotation speed of the rotor;

[0044] a first active instruction value determination unit configured to determine the first active instruction value according to the difference between the pre-set rotation speed instruction value and the first actual rotation speed of the rotor.

[0045] In some embodiments of the application, the first active instruction value determination unit comprises:

[0046] a first active power instruction value determination unit configured to determine a first active power instruction value of the doubly-fed motor according to the difference between the pre-set rotation speed instruction value and the first actual rotation speed of the rotor;

[0047] a first active instruction value determination sub-unit configured to determine the first active instruction value according to the first active power instruction value.

[0048] In some embodiments of the application, the second active instruction value determination module comprises:

[0049] a second active power instruction value determination unit configured to determine a second active power instruction value of the doubly-fed motor according to the rated power;

[0050] a second active instruction value determination sub-unit configured to determine the second active instruction value according to the second active power instruction value.

[0051] In some embodiments of the application, the third active instruction value determination module comprises:

[0052] a sample-and-hold rotation speed determination unit configured to perform sample-and-hold processing on the current rotation speed to determine a sample-and-hold rotation speed instruction value;

[0053] a rotation speed difference determination unit configured to determine a difference between the second actual rotation speed and the sample-and-hold rotation speed instruction value;

[0054] a third active instruction value determination unit configured to determine the third active instruction value according to the difference between the second actual rotation speed and the sample-and-hold rotation speed instruction value.

[0055] In some embodiments of the application, the third active instruction value determination unit comprises:

[0056] a third active power instruction value determination unit configured to determine a third active power instruction value of the doubly-fed motor according to the difference between the second actual rotation speed and the sample-and-hold rotation speed instruction value;

[0057] The third active instruction value determination subunit is configured to determine the third active instruction value according to the third active power instruction value.

[0058] In a fourth aspect, the present application provides a computer program product, comprising computer programs / instructions, which, when executed by a processor, implement the steps of the control method of the high-inertia double-fed motor unit.

[0059] In a fifth aspect, the present application provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the control method of the high-inertia double-fed motor unit when executing the program.

[0060] In a sixth aspect, the present application provides a computer-readable storage medium, which stores a computer program, wherein the computer program, when executed by a processor, implements the steps of the control method of the high-inertia double-fed motor unit.

[0061] As can be seen from the above description, the high-inertia double-fed motor unit and the control method thereof provided by the embodiments of the present application correspond to the high-inertia double-fed motor unit, which comprises a high-rotational-inertia rotor connected with a rotor of a double-fed motor, a rotor-side converter connected with the rotor, a grid-side converter connected with the rotor-side converter through a DC bus, and a step-up transformer connected with the grid-side converter and the stator of the double-fed motor.

[0062] The control method of the corresponding high-inertia double-fed motor unit comprises the following steps: when an AC system in which the high-inertia double-fed motor unit is located is in a normal operation state, determining a first active instruction value of the rotor-side converter according to a pre-set rotor speed instruction value of the double-fed motor; when the AC system is in a fault operation state, determining a second active instruction value of the rotor-side converter according to a rated power of the double-fed motor; and when the AC system is switched from the fault operation state to the normal operation state, determining a third active instruction value of the rotor-side converter according to a current rotor speed of the double-fed motor.

[0063] In summary, the double-fed motor with the high-rotational-inertia rotor reserves a high rotor kinetic energy, and when a fault occurs in the AC system, the rotor kinetic energy is released to provide active frequency support for the system. BRIEF DESCRIPTION OF DRAWINGS

[0064] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0065] Figure 1 A structural schematic diagram of a high-inertia double-fed motor unit provided in an embodiment of the present application;

[0066] Figure 2 A flowchart of a control method of a high-inertia double-fed motor unit provided in an embodiment of the present application Figure 1 ;

[0067] Figure 3 A flowchart of a control method of a high-inertia double-fed motor unit provided in an embodiment of the present application Figure 2 ;

[0068] Figure 4 A flowchart of step 100 provided in an embodiment of the present application;

[0069] Figure 5 A connection diagram of three outer-loop active instruction generation strategies of a rotor controller and a mode switching logic module provided in an embodiment of the present application;

[0070] Figure 6 A flowchart of step 102 provided in an embodiment of the present application;

[0071] Figure 7 A control block diagram of a rotor-side converter RSC provided in an embodiment of the present application;

[0072] Figure 8 A flowchart of step 200 provided in an embodiment of the present application;

[0073] Figure 9 A flowchart of step 300 provided in an embodiment of the present application;

[0074] Figure 10 A control block diagram of a grid-side converter GSC provided in an embodiment of the present application;

[0075] Figure 11 A three-mode switching logic judgment flowchart of a mode switching logic module provided in an embodiment of the present application;

[0076] Figure 12 A flowchart of step 303 provided in an embodiment of the present application;

[0077] Figure 13 A flowchart of a control method of a high-inertia double-fed motor unit provided in a specific application example of the present application;

[0078] Figure 14 A structural schematic diagram of a control device of a high-inertia double-fed motor unit provided in an embodiment of the present application Figure 1 ;

[0079] Figure 15 Fig. 1 is a structural schematic of a control device of a high-inertia double-fed motor set according to an embodiment of the present application. Figure 2

[0080] Figure 16 Fig. 2 is a structural schematic of a first active instruction value determination module according to an embodiment of the present application.

[0081] Figure 17 Fig. 3 is a structural schematic of a first active instruction value determination unit according to an embodiment of the present application.

[0082] Figure 18 Fig. 4 is a structural schematic of a second active instruction value determination module according to an embodiment of the present application.

[0083] Figure 19 Fig. 5 is a structural schematic of a third active instruction value determination module according to an embodiment of the present application.

[0084] Figure 20 Fig. 6 is a structural schematic of a third active instruction value determination unit according to an embodiment of the present application.

[0085] Figure 21 Fig. 7 is a structural schematic of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0086] In the following, the technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, but not all embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0087] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can adopt a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt a computer program product implemented on one or more computer usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program codes.

[0088] ​It should be noted that the terms "comprising" and "having" and any variations thereof in the specification and claims of this application and in the accompanying drawings are intended to cover not only the listed steps or units but also additional steps or units that are not listed but that would be obvious to one skilled in the art in view of the description of the application.

[0089] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0090] Embodiments of the present application provide a specific implementation of a high-inertia doubly-fed motor unit. Specifically, referring to Figure 1 , the high-inertia doubly-fed motor unit specifically includes the following contents:

[0091] A high-rotational-inertia rotor is connected to the rotor of the doubly-fed motor and is coaxially arranged with the rotor.

[0092] A rotor-side converter RSC is connected to the rotor.

[0093] A grid-side converter GSC is connected to the rotor-side converter through a DC bus.

[0094] A step-up transformer is connected to the grid-side converter and the stator of the doubly-fed motor, respectively.

[0095] Figure 1 , i rd and i rq are the d-axis and q-axis components of the rotor current i r in the synchronous coordinate; i sd and i sq are the d-axis and q-axis components of the stator current i s in the synchronous coordinate; i gd and i gq are the d-axis and q-axis components of the grid-side converter current i g in the synchronous coordinate; U pccd and U pccq are the d-axis and q-axis components of the grid-connected point voltage U pcc in the synchronous coordinate; U dc is the voltage value of the DC bus capacitor C; P S and Q S are the active power and reactive power output by the doubly-fed motor stator; P r and Q rrespectively, active power and reactive power flowing into the rotor of the doubly-fed electric machine; P G is the total active power output by the doubly-fed electric machine.

[0096] With reference to the foregoing description Figure 1 In some embodiments of the present application, a high-inertia doubly-fed electric machine set further comprises:

[0097] A DC bus capacitor C is arranged on the DC bus.

[0098] With reference to the foregoing description Figure 1 In some embodiments of the present application, a high-inertia doubly-fed electric machine set further comprises:

[0099] A filter inductance L g is arranged between the grid-side converter and the step-up transformer.

[0100] In some embodiments of the present application, with reference to the foregoing description Figure 2 The present application further provides a control method applied to the high-inertia doubly-fed electric machine set described above, which comprises:

[0101] Step 100: when the AC system in which the high-inertia doubly-fed electric machine set is located is in a normal operating state, determining a first active instruction value of the rotor-side converter according to a pre-set speed instruction value of the doubly-fed electric machine;

[0102] Step 200: when the AC system in which the high-inertia doubly-fed electric machine set is located is in a fault operating state, determining a second active instruction value of the rotor-side converter according to a rated power of the doubly-fed electric machine;

[0103] Step 300: when the AC system is switched from the fault operating state to the normal operating state, determining a third active instruction value of the rotor-side converter according to a current speed of the rotor of the doubly-fed electric machine.

[0104] As can be seen from the foregoing description, the control method of the high-inertia doubly-fed electric machine set provided by the embodiments of the present application comprises: when the AC system in which the high-inertia doubly-fed electric machine set is located is in a normal operating state, determining a first active instruction value of the rotor-side converter according to a pre-set speed instruction value of the doubly-fed electric machine; when the AC system in which the high-inertia doubly-fed electric machine set is located is in a fault operating state, determining a second active instruction value of the rotor-side converter according to a rated power of the doubly-fed electric machine; and when the AC system is switched from the fault operating state to the normal operating state, determining a third active instruction value of the rotor-side converter according to a current speed of the rotor of the doubly-fed electric machine. Specifically, the present application has the following beneficial effects:

[0105] In summary, the application relies on the high rotational inertia rotor of the doubly-fed motor to store more rotational kinetic energy, relies on the wide variable speed operation performance of the doubly-fed motor to realize large amplitude change of rotor speed, and releases a large amount of rotor kinetic energy and converts it into active power, thereby providing active frequency support for the system.

[0106] It can be understood that there is no strict sequence relationship between steps 100, 200 and 300, but the running state of the high-inertia doubly-fed motor set is selected. Specifically, for step 100, it can be simply understood as a constant speed mode; for step 200, it can be simply understood as a constant power mode; for step 300, it can be simply understood as a speed maintaining mode.

[0107] In some embodiments of the application, referring to Figure 3 The control method of the high-inertia doubly-fed motor set further comprises the following steps after step 300:

[0108] Step 400: When the duration of the disappearance of the fault running state reaches the preset time, the first active instruction value is determined according to the pre-set speed instruction value of the doubly-fed motor.

[0109] Specifically, when the fault running state of the high-inertia doubly-fed motor set disappears and lasts for a period of time (preset time), the high-inertia doubly-fed motor set is converted to the constant speed mode of step 100.

[0110] In some embodiments of the application, referring to Figure 4 The first active instruction value is determined according to the pre-set speed instruction value of the doubly-fed motor in step 100, comprising:

[0111] Step 101: determining the difference between the pre-set speed instruction value and the first actual speed of the rotor;

[0112] Step 102: determining the first active instruction value according to the difference between the pre-set speed instruction value and the first actual speed of the rotor.

[0113] In steps 101 and 102, referring to Figure 5 To realize frequency support, three kinds of outer loop active instruction generation strategies of the rotor converter are designed, which are constant speed mode, constant power mode and speed maintaining mode. The output of one of the three control modes is taken as the final output by the mode switching logic module.

[0114] The constant speed mode is used for the constant speed control of the doubly-fed motor when the system is normally running without fault, and the control strategy is as shown in Figure 5 The input signals include: 1) rotor speed instruction value W rref, which is the rated power frequency angular velocity; 2) rotor speed actual value W r . The input is rotor speed actual value W r , and the output is the deviation of rotor speed command value W rref . The proportional coefficient is K ωp , which is 15; the integral coefficient is K ωi , which is 20. S is the Laplace operator. The output is the active power command value P Gref1 of the doubly-fed motor in the constant speed mode.

[0115] In some embodiments of the present application, referring to Figure 6 , step 102 comprises:

[0116] Step 1021: determining the first active power command value of the doubly-fed motor according to the difference between the pre-set rotor speed command value and the first actual rotor speed of the rotor;

[0117] Step 1022: determining the first active command value according to the first active power command value.

[0118] Specifically, referring to Figure 7 , the rotor-side converter double-closed-loop PI proportional / integral control strategy is adopted to implement step 1021 and step 1022, K rPp and K rPi are the proportional and integral coefficients of the active outer loop control respectively; K rdp and K rdi are the proportional and integral coefficients of the active inner loop control respectively; K rQp and K rQi are the proportional and integral coefficients of the reactive outer loop control respectively; K rqp and K rqi are the proportional and integral coefficients of the reactive inner loop control respectively. The meanings of P s and Q s are the same as described above, which are the stator active power and reactive power respectively; i rdref and i rqref are the rotor active and reactive inner loop current command values respectively; the meanings of i rd and i rq are the same as described above, which are the d-axis and q-axis components of rotor current i r ; U rdref and U rqref are the d-axis and q-axis voltage command values of the rotor-side converter RSC generated by the controller respectively. S is the Laplace operator.

[0119] In some embodiments of the present application, referring to Figure 8 , the step of determining the second active command value of the rotor-side converter according to the rated power of the doubly-fed motor in step 200 comprises:

[0120] Step 201: determining a second active power instruction value of the doubly-fed motor according to the rated power;

[0121] Step 202: determining the second active instruction value according to the second active power instruction value.

[0122] In step 201 and step 202, the constant power mode is used to provide active power to the system when the system fails, and frequency support is realized. Figure 5 As shown in the figure, P Gref2 is the active power instruction value, which is the rated power P N of the doubly-fed motor.

[0123] In some embodiments of the present application, referring to Figure 9 , the third active instruction value of the rotor-side converter is determined according to the current rotor speed of the doubly-fed motor in step 300, which includes:

[0124] Step 301: sampling and holding the current rotor speed to determine the instruction value of the sampling and holding rotor speed;

[0125] Step 302: determining the difference between the second actual rotor speed and the instruction value of the sampling and holding rotor speed;

[0126] Step 303: determining the third active instruction value according to the difference between the second actual rotor speed and the instruction value of the sampling and holding rotor speed.

[0127] In step 301 to step 303, the essence is the above-mentioned constant speed mode, which is used to maintain the current rotor speed of the doubly-fed motor after the active power output mode ends. The control strategy is shown in the figure. Figure 5 The input signal is the actual rotor speed W r . The actual rotor speed W r is sampled and held through the S / H sampling / holding link at the moment when the constant speed mode is put into operation to obtain W r0 . The deviation between W r0 and the actual rotor speed W r of the rotor enters the PI proportional / integral link. The parameters and values of the PI proportional / integral link are the same as those in the constant speed mode. The output is the active power instruction value P Gref3 of the doubly-fed motor in the constant speed mode.

[0128] Next, referring to Figure 10 , U dc has the same meaning as before, which is the voltage value of the DC bus capacitor C; U dcref is the DC voltage instruction value; U pccd is the d-axis component of the grid-connected point voltage U pcc in the synchronous coordinate; igdref and i gqref are the command values of the inner loop of the grid-side active and reactive currents respectively; i gd and i gq have the same meaning as the foregoing, and are the grid-side converter currents i g are the d, q axis components in the synchronous coordinate; ω g is the grid voltage U pcc is the electrical angular frequency; L g have the same meaning as the foregoing, and are the grid-side converter filter inductances; K gUp and K gUi are the proportional and integral coefficients of the DC voltage outer loop control respectively; K gdp and K gdi are the proportional and integral coefficients of the active inner loop control respectively; K gqp and K gqi are the proportional and integral coefficients of the reactive inner loop control respectively; U gdref and U gqref are the d-axis and q-axis voltage command values of the grid-side converter GSC generated by the controller; S is the Laplace operator.

[0129] Finally, referring to Figure 11 , P Gref1 , P Gref2 and P Gref3 the input mode switching logic module, according to the logic of the mode switching logic module, the output of one of the three control modes is taken as the final output P Gref , and then the power command value P Gref is divided by the rotor speed W r to obtain the stator power command value P sref as the active command value input of the rotor-side converter double closed-loop control strategy.

[0130] In some embodiments of the present application, referring to Figure 12 , step 303 comprises:

[0131] Step 3031: determining a third active power command value of the double-fed motor according to the difference between the second actual speed and the command value of the sample and hold speed;

[0132] Step 3032: determining the third active command value according to the third active power command value.

[0133] From the above description, the control method of the high-inertia double-fed motor unit provided by the embodiment of the application comprises: when an alternating current system in which the high-inertia double-fed motor unit is located is in a normal operation state, determining a first active instruction value of a rotor-side converter according to a rotational speed instruction value of the double-fed motor that is set in advance; when the alternating current system in which the high-inertia double-fed motor unit is located is in a fault operation state, determining a second active instruction value of the rotor-side converter according to a rated power of the double-fed motor; and when the alternating current system is switched from the fault operation state to the normal operation state, determining a third active instruction value of the rotor-side converter according to a current rotational speed of the rotor of the double-fed motor. Specifically, the application has the following beneficial effects:

[0134] 1. By configuring a high-rotational-inertia rotor coaxial with the rotor of the double-fed motor, the double-fed motor has high rotational inertia, thereby being able to have high rotational kinetic energy.

[0135] 2. When a fault occurs in the system, the kinetic energy of the rotor of the double-fed motor is released to emit active power to the system, thereby providing frequency support for the system.

[0136] To further illustrate the application, the application provides a specific application example of the control method of the high-inertia double-fed motor unit, which is described below with reference to Figure 13 and Figure 11 and specifically comprises the following contents.

[0137] With reference to Figure 11 The mode switching logic module switches among the three control modes according to whether a fault occurs in the system and the length of time after the fault disappears.

[0138] S1: The initial operation mode is the constant-rotational-speed mode.

[0139] The constant-rotational-speed mode functions to maintain high rotational kinetic energy by relying on the high rotational inertia and high rotational speed of the rotor in the normal operation state, thereby preparing for active frequency support.

[0140] S2: Detect whether a fault occurs in the alternating current system. If a fault occurs, switch to the constant-power mode; if no fault occurs, remain in the constant-rotational-speed mode.

[0141] S3: When operating in the constant-power mode, detect whether the fault disappears. If the fault exists, remain in the constant-power mode; if the fault disappears, switch to the rotational speed maintaining mode.

[0142] The constant-power mode functions to emit active power to the system by releasing the kinetic energy of the rotor when a fault occurs in the system, thereby providing active frequency support for the system.

[0143] S4: When running in the rotating speed maintaining mode, it is detected whether the fault disappearance time reaches 3 seconds. If the fault disappearance time is greater than 3 seconds, the rotating speed maintaining mode is switched to the constant rotating speed mode, active power is absorbed from the system to increase the rotating speed to the instruction rotating speed, and the next frequency support is prepared; otherwise, the rotating speed maintaining mode is maintained.

[0144] The rotating speed maintaining mode functions in that, in a short time after the system fault just ends, the current rotating speed of the rotor is maintained, and the system frequency is prevented from dropping due to the rotor rotating speed increasing to absorb power.

[0145] Based on the same inventive concept, the embodiments of the present application further provide a control device of a high-inertia double-fed motor unit, which can be used to implement the method described in the above embodiments, such as the following embodiments. Since the control device of the high-inertia double-fed motor unit solves problems by the similar principle as the control method of the high-inertia double-fed motor unit, the implementation of the control device of the high-inertia double-fed motor unit can be referred to the implementation of the control method of the high-inertia double-fed motor unit, and the repeated parts will not be described herein. The term "unit" or "module" used below can be a combination of software and / or hardware that implements a predetermined function. Although the system described in the following embodiments is preferably implemented in software, the implementation of hardware or a combination of software and hardware is also possible and is conceived.

[0146] The embodiments of the present application provide a specific implementation of a control device of a high-inertia double-fed motor unit capable of implementing a control method of the high-inertia double-fed motor unit, referring to Figure 14 , the control device comprises:

[0147] The first active instruction value determination module 10 is configured to determine a first active instruction value of the rotor-side converter according to a rotating speed instruction value of the double-fed motor pre-set when the AC system where the high-inertia double-fed motor unit is located is in a normal operation state.

[0148] The second active instruction value determination module 20 is configured to determine a second active instruction value of the rotor-side converter according to a rated power of the double-fed motor when the AC system where the high-inertia double-fed motor unit is located is in a fault operation state.

[0149] The third active instruction value determination module 30 is configured to determine a third active instruction value of the rotor-side converter according to a current rotating speed of the rotor of the double-fed motor when the AC system is switched from the fault operation state to the normal operation state.

[0150] In some embodiments of the present application, referring to Figure 15 , the control device of the high-inertia double-fed motor unit further comprises:

[0151] The state cycle module 40 is configured to determine the first active instruction value according to a pre-set rotating speed instruction value of the double-fed motor when the duration of disappearance of the AC system fault operation state reaches a preset time.

[0152] In some embodiments of the present application, referring to Figure 16 , the first active instruction value determination module 10 comprises:

[0153] The difference instruction value determination unit 10a is configured to determine the difference between the pre-set rotating speed instruction value and the first actual rotating speed of the rotor.

[0154] The first active instruction value determination unit 10b is configured to determine the first active instruction value according to the difference between the pre-set rotating speed instruction value and the first actual rotating speed of the rotor.

[0155] In some embodiments of the present application, referring to Figure 17 , the first active instruction value determination unit 10b comprises:

[0156] The first active power instruction value determination unit 10b1 is configured to determine the first active power instruction value of the double-fed motor according to the difference between the pre-set rotating speed instruction value and the first actual rotating speed of the rotor.

[0157] The first active instruction value determination sub-unit 10b2 is configured to determine the first active instruction value according to the first active power instruction value.

[0158] In some embodiments of the present application, referring to Figure 18 , the second active instruction value determination module 20 comprises:

[0159] The second active power instruction value determination unit 20a is configured to determine the second active power instruction value of the double-fed motor according to the rated power.

[0160] The second active instruction value determination sub-unit 20b is configured to determine the second active instruction value according to the second active power instruction value.

[0161] In some embodiments of the present application, referring to Figure 19 , the third active instruction value determination module 30 comprises:

[0162] The sample-and-hold rotating speed determination unit 30a is configured to perform sample-and-hold processing on the current rotating speed to determine a sample-and-hold rotating speed instruction value.

[0163] The rotating speed difference determination unit 30b is configured to determine the difference between the second actual rotating speed and the sample-and-hold rotating speed instruction value.

[0164] The third active instruction value determination unit 30c is configured to determine the third active instruction value according to the difference between the second actual rotating speed and the instruction value of the sample holding rotating speed.

[0165] In some embodiments of the present application, referring to Figure 20 , the third active instruction value determination unit 30c comprises:

[0166] The third active power instruction value determination unit 30c1 is configured to determine the third active power instruction value of the double-fed motor according to the difference between the second actual rotating speed and the instruction value of the sample holding rotating speed.

[0167] The third active instruction value determination sub-unit 30c2 is configured to determine the third active instruction value according to the third active power instruction value.

[0168] From the above description, it can be known that the control device for the high-inertia double-fed motor unit provided by the embodiments of the present application comprises: a first active instruction value determination module, configured to determine the first active instruction value of the rotor-side converter according to the rotating speed instruction value of the double-fed motor when the AC system in which the high-inertia double-fed motor unit is located is in a normal operating state; a second active instruction value determination module, configured to determine the second active instruction value of the rotor-side converter according to the rated power of the double-fed motor when the AC system in which the high-inertia double-fed motor unit is located is in a fault operating state; and a third active instruction value determination module, configured to determine the third active instruction value of the rotor-side converter according to the current rotating speed of the rotor of the double-fed motor when the AC system is switched from the fault operating state to the normal operating state.

[0169] In summary, the present application relies on the high rotating inertia rotor of the double-fed motor to store more rotating kinetic energy, relies on the wide variable speed operating performance of the double-fed motor to realize large amplitude change of the rotor rotating speed, and releases a large amount of rotor kinetic energy and converts it into active power, thereby providing active frequency support for the system.

[0170] The embodiments of the present application also provide a specific implementation of an electronic device capable of realizing all the steps in the control method for the high-inertia double-fed motor unit in the above embodiments, referring to Figure 21 , the electronic device specifically comprises the following contents:

[0171] a processor 1201, a memory 1202, a communications interface 1203 and a bus 1204;

[0172] The processor 1201, the memory 1202 and the communication interface 1203 complete communication with each other through the bus 1204; the communication interface 1203 is used for realizing information transmission between the server-side device, the power measurement device, the user-side device and other related devices.

[0173] The processor 1201 is used for calling the computer program in the memory 1202, and when the processor executes the computer program, all steps in the control method of the high-inertia double-fed motor unit in the above embodiment are realized, for example, when the processor executes the computer program, the following steps are realized:

[0174] Step 100: when the AC system where the high-inertia double-fed motor unit is located is in a normal operation state, determining a first active instruction value of the rotor-side converter according to a pre-set speed instruction value of the double-fed motor;

[0175] Step 200: when the AC system where the high-inertia double-fed motor unit is located is in a fault operation state, determining a second active instruction value of the rotor-side converter according to a rated power of the double-fed motor;

[0176] Step 300: when the AC system is changed from the fault operation state to the normal operation state, determining a third active instruction value of the rotor-side converter according to a current speed of the rotor of the double-fed motor.

[0177] The embodiment of the application also provides a computer readable storage medium capable of realizing all steps in the control method of the high-inertia double-fed motor unit in the above embodiment, and the computer readable storage medium has a computer program stored thereon, and when the processor executes the computer program, all steps in the control method of the high-inertia double-fed motor unit in the above embodiment are realized, for example, when the processor executes the computer program, the following steps are realized:

[0178] Step 100: when the AC system where the high-inertia double-fed motor unit is located is in a normal operation state, determining a first active instruction value of the rotor-side converter according to a pre-set speed instruction value of the double-fed motor;

[0179] Step 200: when the AC system where the high-inertia double-fed motor unit is located is in a fault operation state, determining a second active instruction value of the rotor-side converter according to a rated power of the double-fed motor;

[0180] Step 300: when the AC system is changed from the fault operation state to the normal operation state, determining a third active instruction value of the rotor-side converter according to a current speed of the rotor of the double-fed motor.

[0181] Each of the embodiments in the present specification is described in a progressive manner, and the same or similar parts among the embodiments can be mutually referred to. Each of the embodiments focuses on the difference from other embodiments. In particular, for the hardware + program type embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the part of the method embodiments.

[0182] The above describes specific embodiments of the present specification. Other embodiments are within the scope of the appended claims. In some cases, the acts or steps recited in the claims can be performed in a different order than the order in which they are recited and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve the desired results. In certain implementations, multitasking and parallel processing can be advantageous.

[0183] Although the present application provides method operation steps as embodiments or flowcharts, more or less operation steps can be included based on routine or non-creative labor. The order of steps listed in the embodiments is only one of the many execution orders of the steps, and does not represent the only execution order. When the device or client product is executed in practice, the method order shown in the embodiments or the accompanying drawings can be executed in sequence or in parallel (for example, in the environment of parallel processors or multi-threaded processing).

[0184] The present application is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, as well as combinations of flows and / or blocks in the flowcharts 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, a special-purpose computer, an embedded processor, or other programmable data processing apparatus to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing apparatus produce an apparatus that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus that implements the functions specified in the flowcharts and / or block diagrams.

[0185] These computer program instructions can also be stored in a computer-readable memory that can direct the computer or other programmable data processing apparatus to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including instruction apparatus, which implements the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus that implements the functions specified in the flowcharts and / or block diagrams.

[0186] These computer program instructions can also be loaded into a computer or other programmable data processing devices, so that a series of operational steps are generated to realize the computer-implemented processes, and the instructions executed on the computer or other programmable devices provide a process for implementing the functions specified in the flowchart Figure 1 one flow or multiple flows and / or the functions specified in the block Figure 1 one flow or multiple flows and / or the functions specified in the block

[0187] The principles and implementation manners of the present application are described in the specific embodiments. The above embodiment descriptions are only used to help understand the method and core idea of the present application; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manners and application ranges will be changed, and the above descriptions should not be understood as limitations on the present application.

Claims

1. A control method for a high-inertia doubly-fed generator unit, characterized in that, The high-inertia doubly-fed generator unit includes: A high moment of inertia rotor is connected to the rotor of a doubly-fed motor; A rotor-side converter is connected to the rotor; The grid-side converter is connected to the rotor-side converter via a DC bus. The step-up transformer is connected to the stator of the grid-side converter and the doubly-fed motor, respectively. DC bus capacitor, which is installed on the DC bus; A filter inductor is disposed between the grid-side converter and the step-up transformer; The control method includes: When the AC system where the high-inertia doubly-fed motor unit is located is in normal operation, the first active power command value of the rotor-side converter is determined according to the speed command value preset by the doubly-fed motor. When the AC system where the high-inertia doubly-fed generator unit is located is in a fault operation state, the second active power command value of the rotor-side converter is determined according to the rated power of the doubly-fed generator. When the AC system changes from a fault operation state to a normal operation state, the third active power command value of the rotor-side converter is determined according to the current speed of the rotor of the doubly fed motor. When the duration of the disappearance of the fault operation state of the AC system reaches a preset time, the first active power command value is determined according to the speed command value preset by the doubly fed motor. Specifically, after the fault operation state of the high inertia doubly fed motor unit disappears and continues for the preset time, the high inertia doubly fed motor unit is switched to the constant speed mode of the normal operation state.

2. The control method according to claim 1, characterized in that, The step of determining the first active power command value based on the preset speed command value of the doubly-fed motor includes: Determine the difference between the preset speed command value and the first actual speed of the rotor; The first active power command value is determined based on the difference between the preset speed command value and the first actual speed of the rotor.

3. The control method according to claim 2, characterized in that, Determining the first active power command value based on the difference between the preset speed command value and the first actual speed of the rotor includes: The first active power command value of the doubly fed motor is determined based on the difference between the preset speed command value and the first actual speed of the rotor; The first active power command value is determined based on the first active power command value.

4. The control method according to claim 1, characterized in that, Determining the second active power command value of the rotor-side converter based on the rated power of the doubly-fed motor includes: The second active power command value of the doubly-fed motor is determined based on the rated power; The second active power command value is determined based on the second active power command value.

5. The control method according to claim 1, characterized in that, The third active power command value of the rotor-side converter is determined based on the current rotor speed of the doubly-fed motor, including: The current rotational speed is sampled and held to determine the command value of the sampled and held rotational speed; Determine the difference between the second actual rotational speed and the commanded value of the sampled and held rotational speed; The third active power command value is determined based on the difference between the second actual rotational speed and the command value of the sample-and-hold rotational speed.

6. The control method according to claim 5, characterized in that, The third active power command value is determined based on the difference between the second actual rotational speed and the command value of the sample-and-hold rotational speed, including: The third active power command value of the doubly fed motor is determined based on the difference between the second actual speed and the command value of the sample-and-hold speed. The third active power command value is determined based on the third active power command value.

7. A control device for a high-inertia doubly-fed generator unit, characterized in that, The high-inertia doubly-fed generator unit includes: A high moment of inertia rotor is connected to the rotor of a doubly-fed motor; A rotor-side converter is connected to the rotor; The grid-side converter is connected to the rotor-side converter via a DC bus. The step-up transformer is connected to the stator of the grid-side converter and the doubly-fed motor, respectively. DC bus capacitor, which is installed on the DC bus; A filter inductor is disposed between the grid-side converter and the step-up transformer; The control device includes: The first active power command value determination module is used to determine the first active power command value of the rotor-side converter based on the speed command value preset by the doubly fed motor when the AC system where the high inertia doubly fed motor unit is located is in normal operation. The second active power command value determination module is used to determine the second active power command value of the rotor-side converter based on the rated power of the doubly fed motor when the AC system where the high inertia doubly fed motor unit is located is in a fault operation state. The third active power command value determination module is used to determine the third active power command value of the rotor-side converter based on the current speed of the rotor of the doubly fed motor when the AC system changes from a fault operation state to the normal operation state. The state loop module is used to determine the first active power command value according to the preset speed command value of the doubly-fed motor when the duration of the disappearance of the fault operation state of the AC system reaches a preset time. Specifically, after the fault operation state of the high-inertia doubly-fed motor unit disappears and continues for the preset time, the high-inertia doubly-fed motor unit is switched to the constant speed mode of the normal operation state.

8. The control device according to claim 7, characterized in that, The first active power command value determination module includes: The instruction value difference determination unit is used to determine the difference between the preset speed instruction value and the first actual speed of the rotor; The first active power command value determination unit is used to determine the first active power command value based on the difference between the preset speed command value and the first actual speed of the rotor.

9. The control device according to claim 8, characterized in that, The first active power command value determination unit includes: The first active power command value determination unit is used to determine the first active power command value of the doubly fed motor based on the difference between the preset speed command value and the first actual speed of the rotor. The first active power command value determination subunit is used to determine the first active power command value based on the first active power command value.

10. The control device according to claim 7, characterized in that, The second active power command value determination module includes: The second active power command value determination unit is used to determine the second active power command value of the doubly fed motor based on the rated power. The second active power command value determination subunit is used to determine the second active power command value based on the second active power command value.

11. The control device according to claim 7, characterized in that, The third active power command value determination module includes: A sample-and-hold speed determination unit is used to perform sample-and-hold processing on the current speed to determine the command value of the sample-and-hold speed; The rotational speed difference determination unit is used to determine the difference between the second actual rotational speed and the command value of the sampled and held rotational speed; The third active power command value determination unit is used to determine the third active power command value based on the difference between the command value of the second actual rotational speed and the sample-and-hold rotational speed.

12. The control device according to claim 11, characterized in that, The third active power command value determination unit includes: The third active power command value determination unit is used to determine the third active power command value of the doubly fed motor based on the difference between the command value of the second actual speed and the sample-and-hold speed. The third active power command value determination subunit is used to determine the third active power command value based on the third active power command value.

13. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the control method for the high inertia doubly fed motor unit according to any one of claims 1 to 6.

14. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of the control method for a high-inertia doubly-fed generator unit as described in any one of claims 1 to 6.

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