Voltage support control method for high-quality power supply equipment

Abstract

The invention relates to the technical field of voltage control, and discloses a voltage support control method for high-quality power supply equipment. The equipment voltage support control method comprises the following steps: acquiring equipment electrical quantity information in real time; performing Q-V droop control on the difference value between the actual voltage and the given voltage to generate a reactive power reference value; performing integral operation on the reactive power reference value and the actual reactive power to generate a first internal potential instruction value; the first internal potential instruction value generates a second internal potential instruction value through an adaptive voltage compensation control strategy; a current instruction reference value is obtained from the second internal potential instruction value through a virtual impedance control strategy; the current instruction reference value and the actual current pass through the PI controller to obtain a modulation wave, and the modulation wave and the triangular carrier pass through the modulation module to obtain a switching tube driving signal. According to the equipment voltage support control method, the voltage of the grid-connected point is controlled through the adaptive voltage compensation control strategy, the equipment can provide reactive power output to the maximum extent, and the voltage support capability is improved.

Description

Technical Field

[0001] This invention relates to the field of voltage control technology, specifically to a voltage support control method for high-quality power supply equipment. Background Technology

[0002] With the continuous development of society and the economy, the demand for electricity resources in all sectors of society is increasing day by day. Voltage sag faults are a typical power quality problem. This fault refers to an abnormal drop in the root mean square value of the supply voltage within a short period of time, rapidly decreasing to 10% to 90% of the rated voltage and lasting for 10ms to 1 minute before automatically recovering. During this process, voltage sags may cause the shutdown of sensitive equipment, resulting in irreparable economic losses to social production.

[0003] When grid-connected converters and energy storage devices such as batteries or supercapacitors form a grid-connected system, they have voltage source characteristics, large inertia, and strong resistance to grid disturbances. They can provide stable voltage support when the grid experiences voltage dips or power outages.

[0004] Existing grid-type converters employ virtual synchronous machine technology, and the voltage control stage typically uses reactive voltage droop control. For example... Figure 1 As shown, when the system voltage is subjected to a fault or disturbance, the voltage change ΔU is controlled by QV droop (droop coefficient k). v The reactive power reference value Q is then generated. ref Combined with the current reactive power output Q, after the integration process (integration operation), the internal potential command value is generated.

[0005] The inventors of this application have discovered that when a voltage dip occurs in the power grid, due to reactive voltage droop control, the converter cannot provide maximum reactive power output in some operating conditions, affecting the voltage support effect. Summary of the Invention

[0006] The purpose of this invention is to provide a high-quality power supply equipment voltage support control method to solve the problems mentioned in the background art.

[0007] This invention provides a voltage support control method for high-quality power supply equipment, comprising the following steps:

[0008] The S1 power supply equipment is connected to the local load based on a common coupling point and is connected to the power grid;

[0009] S2 collects electrical quantity information of power supply equipment in real time;

[0010] S3 generates a reactive power reference value Q based on the difference ΔU between the actual voltage and the given voltage, after QV droop control. ref ;

[0011] S4 is based on the reactive power reference value Q. ref The first internal potential command value E is generated by integrating the actual reactive power Q_fbk. ref ;

[0012] S5 will assign the first internal potential command value E ref After the adaptive voltage compensation control strategy, the second internal potential command value E is generated. ref ';

[0013] S6 The second internal potential command value E ref After applying the virtual impedance control strategy, the current command reference value Idq_ref is obtained;

[0014] S7 obtains the PWM modulation wave of the power supply equipment based on the current command reference value and the actual current after passing through the PI controller. The PWM modulation wave and the triangular carrier are then passed through the PWM modulation module to obtain the switching transistor drive signal, so as to control the switching transistor of the power supply equipment to turn on and off.

[0015] Based on the above scheme, it can be seen that the high-quality power supply equipment voltage support control method of the present invention has a reactive power reference value Q. ref The actual reactive power Q_fbk is integrated to generate the first internal potential command value E. ref Then, the first internal potential command value E is set. ref After applying the adaptive voltage compensation control strategy, the second internal potential command value E is generated. ref Then, through a virtual impedance control strategy, a current command reference value is obtained. This current command reference value and the actual current are then processed by a PI controller to obtain the PWM modulation wave of the power supply equipment. The PWM modulation wave, along with a triangular carrier wave, is then processed by a PWM modulation module to obtain the switching transistor drive signal, which controls the on / off state of the power supply equipment's switching transistors. An adaptive voltage compensation control strategy is used to control the grid connection point voltage. When the system voltage experiences a temporary drop, the power supply equipment can provide maximum reactive power output, improving the system's voltage support capability. When the system voltage is normal, this strategy will not affect the steady-state operation of the equipment.

[0016] In one feasible approach, in step S5, the first internal potential command value E ref After the adaptive voltage compensation control strategy, the second internal potential command value E is generated. ref The method is as follows:

[0017] The difference ΔU between the actual voltage and the given voltage is passed through a PI controller and used as the internal potential voltage command increment ΔE. ref Superimposed on the first internal potential command value E ref The second internal potential command value E is obtained. ref ', E ref '=Eref +ΔE ref .

[0018] In one feasible approach, the difference ΔU between the actual voltage and the given voltage is provided with a dead zone.

[0019] In one feasible solution, step S5 further includes:

[0020] S51 generates a second internal potential command value E ref 'Limited amplitude'.

[0021] In one feasible approach, the amplitude limit is calculated in step S51 as follows:

[0022] E ref ' _max =-i sq *ωL v +u sd .

[0023] Among them, i sq The set reactive current threshold is ω, where ω is the angular frequency, and L is the value of L. v For virtual inductance, ωL v The virtual impedance value, u sd This represents the grid-side D-axis voltage.

[0024] The high-quality power supply equipment voltage support control method of the present invention achieves control of the grid connection point voltage by adding an adaptive voltage compensation control strategy, so that when the system voltage drops, the power supply equipment can increase reactive power output and improve the voltage support capability of the equipment. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of voltage control in the prior art of this invention;

[0027] Figure 2 This is a flowchart illustrating the voltage support control method for high-quality power supply equipment in an embodiment of the present invention.

[0028] Figure 3 This is a schematic diagram of the adaptive voltage compensation control strategy in an embodiment of the present invention;

[0029] Figure 4This is a schematic diagram illustrating the generation of the current command reference value in an embodiment of the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0033] The technical solution of the present invention will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0034] As described in the background section of this application, existing grid-type converters employ virtual synchronous machine technology, and the voltage control stage typically uses reactive voltage droop control. Figure 1 As shown, when the system voltage is subjected to a fault or disturbance, the voltage change ΔU is controlled by QV droop (droop coefficient k). v The reactive power reference value Q is then generated. ref Combined with the current reactive power output Q, after the integration process (integration operation), the internal potential command value is generated.

[0035] The inventors of this application have discovered that when a voltage dip occurs in the power grid, due to reactive voltage droop control, the converter cannot provide maximum reactive power output in some operating conditions, affecting the voltage support effect.

[0036] To address the aforementioned problems, the inventors of this application have proposed a technical solution, the specific embodiments of which are as follows:

[0037] Figure 2 This is a flowchart illustrating the voltage support control method for high-quality power supply equipment in an embodiment of the present invention. Figure 3 This is a schematic diagram of the adaptive voltage compensation control strategy in an embodiment of the present invention. Figure 4 This is a schematic diagram illustrating the generation of the current command reference value in an embodiment of the present invention.

[0038] like Figures 2 to 4 As shown, the high-quality power supply equipment voltage support control method of this embodiment includes the following steps:

[0039] The S1 power supply equipment is connected to the local load based on a common coupling point and is connected to the power grid.

[0040] S2 collects and updates electrical quantity information parameters of power supply equipment in real time.

[0041] S3 generates a reactive power reference value Q based on the difference ΔU between the actual voltage and the given voltage through QV droop control. ref .

[0042] Specifically, based on the difference ΔU between the real-time acquired actual voltage U_ref and the given voltage reference value U_fbk, the voltage is controlled by QV (reactive power - voltage) droop (droop coefficient k). v After that, the reactive power reference value Q is obtained. ref .

[0043] S4 is based on the reactive power reference value Q. ref The first internal potential command value E is generated by integrating the actual reactive power Q_fbk. ref Eref

[0044] Specifically, the reactive power reference value Q obtained in step S3 is... ref Based on the current actual reactive power Q_fbk, the first internal potential command value E is generated after integration. ref .

[0045] S5 First internal potential command value E ref The second internal potential command value E is generated through an adaptive voltage compensation control strategy. ref '.

[0046] Specifically, the first internal potential command value E obtained in step S4 is...ref After the adaptive voltage compensation control strategy, a new second internal potential command value E is generated. ref '.

[0047] S6 The second internal potential command value E ref After applying the virtual impedance control strategy, the current command reference value Idq_ref is obtained.

[0048] Specifically, the second internal potential command value E obtained in step S5 is... ref After applying the virtual impedance control strategy, the current command reference value Idq_ref is obtained.

[0049] The S7 current command reference value Idq_ref and the actual current are passed through the PI controller to obtain the PWM modulation wave of the power supply equipment. The PWM modulation wave and the triangular carrier are passed through the PWM modulation module to obtain the switching transistor drive signal, so as to control the switching transistor of the power supply equipment to turn on and off.

[0050] Specifically, the obtained current command reference value Idq_ref and the real-time acquired actual current are processed by a PI controller to obtain the PWM modulation wave of the power supply equipment. The PWM modulation wave and the triangular carrier are then processed by a PWM modulation module to obtain the switching transistor drive signal. This drive signal is used to control the switching transistor of the power supply equipment to turn on and off.

[0051] It is not difficult to see from the above that the high-quality power supply equipment voltage support control method of this embodiment has a reactive power reference value Q. ref The actual reactive power Q_fbk is integrated to generate the first internal potential command value E. ref Then, the first internal potential command value E is set. ref After applying the adaptive voltage compensation control strategy, the second internal potential command value E is generated. ref Then, through a virtual impedance control strategy, a current command reference value is obtained. This current command reference value and the actual current are then processed by a PI controller to obtain the PWM modulation wave of the power supply equipment. The PWM modulation wave, along with a triangular carrier wave, is then processed by a PWM modulation module to obtain the switching transistor drive signal, which controls the on / off state of the power supply equipment's switching transistors. An adaptive voltage compensation control strategy is used to control the grid connection point voltage. When the system voltage experiences a temporary drop, the power supply equipment can provide maximum reactive power output, improving the system's voltage support capability. When the system voltage is normal, this strategy will not affect the steady-state operation of the equipment.

[0052] Optionally, in the high-quality power supply equipment voltage support control method of this embodiment, in step S5, the first internal potential command value E ref After the adaptive voltage compensation control strategy, a second internal potential command value E is generated. ref The method is as follows:

[0053] The difference ΔU between the actual voltage collected and the set given voltage is processed by a PI controller and used as the internal potential voltage command increment ΔE. ref Superimposed on the first internal potential command value E ref The second internal potential command value E is obtained. ref ':

[0054] E ref ' = E ref +ΔE ref .

[0055] Furthermore, in the high-quality power supply equipment voltage support control method of this embodiment, in step S5, the difference ΔU between the real-time collected actual voltage and the set given voltage is set with a dead zone to avoid saturation.

[0056] Optionally, the high-quality power supply equipment voltage support control method in this embodiment further includes, in step S5:

[0057] S51 generates the final second internal potential command value E. ref 'Limit the amplitude.'

[0058] Furthermore, in the high-quality power supply equipment voltage support control method of this embodiment, in step S51, the second internal potential command value E ref The method for calculating the limit size of ' is as follows:

[0059] E ref ' _max =-i sq *ωL v +u sd .

[0060] Among them, E ref ' _max The second internal potential command value E ref The limiting value of ', i sq The maximum reactive current threshold set for the equipment, ω is the angular frequency of the equipment, and L v For the virtual inductance of the device, ωL v u is the virtual impedance value of the device. sd The grid-side D-axis voltage is calculated from the collected grid-side voltage through Dq transformation.

[0061] In this invention, unless otherwise explicitly specified and limited, the first feature being "on" or "below" the second feature can mean that the first feature and the second feature are in direct contact, or that the first feature and the second feature are in indirect contact through an intermediate medium.

[0062] Furthermore, "above," "on top of," and "above" the first feature in relation to the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "under," and "beneath" the first feature in relation to the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0063] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-quality power supply device voltage support control method, characterized by, The method comprises the following steps: S1, a power supply device is connected with a local load based on a point of common coupling and accesses a power grid; S2, electrical quantity information of the power supply device is collected in real time; S3 generates the reactive power reference value Q based on the difference ΔU between the actual voltage and the given voltage after Q-V droop control ref ; S4 generates a first internal voltage command value E based on the reactive power reference value Q ref ref ;​ S5 sets the first inner potential command value E ref After adaptive voltage compensation control strategy, the second inner potential command value E ref ' ; S6 the second internal potential instruction value E ref After the virtual impedance control strategy, the current instruction reference value Idq_ref is obtained. S7, a PWM modulation wave of the power supply device is obtained based on the current instruction reference value and the actual current after passing through a PI controller, the PWM modulation wave and a triangular carrier wave pass through a PWM modulation module to obtain a switch tube driving signal to control the on-off of the switch tube of the power supply device.

2. The high-quality power supply device voltage support control method according to claim 1, characterized by, In step S5, the first internal potential command value E ref After the adaptive voltage compensation control strategy, the second internal potential command value E ref The method of the application is characterized in that: The difference ΔU between the actual voltage and the given voltage is passed through a PI controller to be used as an inner electromotive voltage command increment ΔE ref is superimposed on the first inner electromotive command value E ref The second inner electromotive command value E ref is obtained as follows. E ref ' = E ref ΔE ref .

3. The high-quality power supply device voltage support control method according to claim 2, characterized by, The difference ΔU between the actual voltage and the given voltage is provided with a dead zone.

4. The high-quality power supply device voltage support control method according to claim 1, characterized by, In step S5, further comprising: S51 generates a second internal potential command value E ref clipping.

5. The high-quality power supply device voltage support control method according to claim 4, characterized by, In step S51, the calculation method of the limiting value is: E ref _max sq v sd .​​​​ where i sq is a set reactive current threshold, ω is an angular frequency, L v is a virtual inductance, ωL v is a virtual impedance value, u sd is a grid-side D-axis voltage.

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