A comprehensive device for coordinated governance of primary frequency modulation and power quality

Abstract

The application discloses a kind of primary frequency modulation and electric energy quality collaborative governance integrated device, the present application relates to electric energy coordinated management technical field, it is solved that the technical problem that function is divided and leads to equipment redundancy and coordination difficulty, capacity allocation lacks priority management, system is out of control when overload, the present application is integrated in same integrated system by primary frequency modulation, reactive power compensation, harmonic suppression and three-phase imbalance governance, replaces traditional multiple separate devices, reduces hardware procurement cost, installation space requirement and operation and maintenance management burden, while unified control architecture eliminates cross-system communication delay, shortens the total response time of frequency detection to power output, improves primary frequency modulation action qualification rate, sets the fixed priority of primary frequency modulation, voltage regulation, harmonic compensation, and uses hierarchical limiting method for capacity dynamic allocation, low priority task is automatically derated or exits, to ensure that primary frequency modulation function is always fully guaranteed under the emergency state of power grid frequency.

Description

Technical Field

[0001] This invention relates to the field of power coordination and management technology, specifically to a comprehensive device for the coordinated management of primary frequency regulation and power quality. Background Technology

[0002] In power systems, primary frequency regulation and power quality management are two important tasks to ensure the safe and stable operation of the power grid. Traditional solutions typically use independent devices to perform these functions: primary frequency regulation is achieved by an energy storage coordinating controller in conjunction with an energy storage converter, while power quality management is performed by dedicated devices such as static var generators and active power filters.

[0003] However, in the existing technology, the primary frequency regulation device and the power quality management device operate independently and lack a unified collaborative control mechanism. When the grid frequency fluctuates, the primary frequency regulation device quickly adjusts the active power output, but this process is often accompanied by passive changes in reactive power, which may aggravate voltage fluctuations and deteriorate power quality. Conversely, when the power quality management device performs reactive power compensation or harmonic suppression, it will also affect the distribution of active power and cause secondary frequency disturbances. Meanwhile, existing technologies attempt to simply superimpose frequency regulation and governance functions onto the same converter, but have not established a dynamic capacity management mechanism based on task priority. When the active frequency regulation command and the reactive / harmonic compensation command both exceed the converter's capacity limit, the system often experiences command conflicts, output distortion, or even protective shutdown, causing all functions to fail simultaneously and seriously threatening grid security. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a comprehensive device for the coordinated management of primary frequency regulation and power quality, which solves the problems of equipment redundancy and coordination difficulties caused by functional separation, lack of priority management in capacity allocation, and system malfunction under overload.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a comprehensive device for the coordinated management of primary frequency regulation and power quality, comprising: The sampling and detection module is used to collect the three-phase voltage and three-phase current at the grid connection point in real time, and to perform frequency and active power state detection, voltage and reactive power state detection, and harmonic and imbalance detection. At the same time, the detection results are transmitted to the multi-target current command generation module. The multi-target current command generation module generates three current command components in parallel under a unified dq rotating coordinate system based on the detection results. These components include the primary frequency regulation active current component, the voltage regulation reactive current component, and the harmonic compensation current component. The module then transmits the three current command components to the priority coordination and dynamic limiting module. Priority coordination and dynamic limiting module: This module is used to dynamically coordinate current commands based on set priorities. The first priority is the active current component of primary frequency regulation, the second priority is the reactive current component of voltage regulation, and the third priority is the harmonic compensation current component. It generates coordination information and transmits it to the high-bandwidth current inner loop control module. A high-bandwidth current inner loop control module is used to input the total current command after priority arbitration into the current inner loop controller for tracking. The current inner loop adopts a proportional resonant controller. The active-reactive dynamic decoupling control module is used to perform decoupling control based on the current inner loop tracking control. In the current inner loop, the voltage equation of the converter in the dq synchronous rotating coordinate system is established. The feedforward compensation term is superimposed on the original current inner loop output to obtain the actual output voltage command. Cross feedforward compensation is introduced in the power outer loop, and the compensation amount is superimposed on the current command for correction and priority coordination.

[0006] As a further aspect of the present invention, the sampling and detection module performs frequency and active power state detection, voltage and reactive power state detection, and harmonic and imbalance detection in the following manner: Frequency and active power status detection: Extract the frequency f of the fundamental positive sequence component from the three-phase voltage and calculate the frequency deviation. ,in The rated frequency; Voltage and reactive power status detection includes: according to the formula The voltage deviation is calculated, where Rated voltage; Harmonic and imbalance detection includes: calculating the required reactive power Q of the system through instantaneous reactive power theory, specifically... ,in and This represents the voltage components along the a-axis and b-axis in a three-phase voltage. and For three-phase current in and The phase angle of the fundamental positive sequence component is obtained through a phase-locked loop, and the three-phase current is transformed into the dq synchronous rotating coordinate system via Park transform to obtain the fundamental active current. and fundamental reactive current To extract specific harmonics, a rotating coordinate system corresponding to the harmonic order is established. After low-pass filtering, the dq component of the harmonic current is obtained. The negative sequence current component is extracted by the negative sequence synchronous rotating coordinate system. The extracted harmonics and negative sequence components are inverted to obtain the harmonic current command to be compensated.

[0007] As a further aspect of the present invention, the generation of the primary frequency-modulated active current component is as follows: According to frequency deviation Calculate active power regulation Its calculation formula is ,in The active power-frequency droop factor is... This is the virtual inertia coefficient; When the State of Charge (SOC) is higher than the upper threshold, the forward charging power command is corrected in reverse; when the SOC is lower than the lower threshold, the reverse discharging power command is corrected in reverse, resulting in the corrected active power regulation. Next, adjust the active power. The conversion formula for active current command is as follows: ,in This represents the d-axis voltage component.

[0008] As a further aspect of the present invention, the generation of the voltage-regulated reactive current component and the harmonic compensation current component is as follows: The reactive current component of voltage regulation is generated as follows: based on the voltage deviation. Combined with reactive power demand Q, and the calculation formula The amount of reactive power that needs to be adjusted is calculated. ,in The reactive power-frequency droop factor; When the system power factor is detected to be lower than the set value, reactive power output is automatically increased until the power factor recovers to the target range, at which point the final reactive power adjustment command is issued. The reactive power regulation is obtained by adding the voltage droop control quantity and the power factor adjustment quantity, converting the reactive power regulation quantity into a q-axis reactive current command, according to the calculation formula. The voltage regulation reactive current component was calculated. , Represents the q-axis voltage component; The harmonic compensation current component is generated by inverting the extracted harmonics and negative sequence components to generate the compensation current command. .

[0009] As a further aspect of the present invention, the priority coordination and dynamic limiting module is based on a set priority dynamic coordination current command in the following manner: Set the rated apparent power capacity of the converter to be The current capacity used for active power output is The remaining capacity is When the apparent power required by the total current command does not exceed At that time, the three instructions are directly superimposed. Receive total current command when the apparent power required by the total current command exceeds At that time, a graded amplitude limiting method is used to reduce the amplitude of lower priority instructions in order of priority.

[0010] As a further aspect of the present invention, the method of using a graded amplitude limiting method to sequentially reduce the amplitude of lower priority instructions according to priority is as follows: The third priority harmonic compensation current component Multiply by a reduction factor and recalculate Obtain the corrected remaining capacity and with If a comparison is made, Not exceeding Then the reduction coefficient is fixed. The first and second priorities remain unchanged; If the reduction coefficient is After dropping to 0 Still more Then, the second priority command is further reduced, and the voltage regulation reactive current component of the second priority is reduced. Multiply by a coefficient Recalculate; like If the load remains at 0, the controller will automatically trigger overload protection, temporarily reducing the amplitude of the first priority command to within the allowable range, and simultaneously sending an alarm signal to the upper-level system. When detected Three consecutive cycles below At this time, the controller gradually restores the reduced low-priority instructions, first restoring the second priority, and then restoring the third priority after stabilization.

[0011] As a further aspect of the present invention, the proportional resonant controller includes: Its transfer function is ,in For proportional gain, the specific calculation formula is as follows: Where L is the AC side filter inductance of the converter. For the switching cycle, Let H be the damping ratio, and H be the set of harmonic orders that need to be compensated. Let h be the resonant gain of the h-th resonant term. For the resonant bandwidth, ω is the fundamental angular frequency.

[0012] As a further aspect of the present invention, the active-reactive dynamic decoupling control module performs decoupling control based on the current inner loop tracking control in the following manner: The controller establishes the voltage equations of the converter in the dq synchronous rotating coordinate system, specifically... and ,in and For cross-coupling terms, and As a resistance voltage drop term, the controller adds a feedforward compensation term to the original inner current loop output, so that the actual output voltage command of the converter is... and ,in and This refers to the adjustment amount generated by the inner loop current controller based on the current deviation. The grid angular frequency is output in real time by the phase-locked loop. After the decoupling of the inner current loop is completed, cross-feedforward compensation is introduced in the outer power loop.

[0013] As a further aspect of the present invention, the method of introducing cross-feedforward compensation in the power outer loop is as follows: When the rate of change of active power is detected When the threshold is exceeded, a compensation amount is injected into the reactive current command. ,in The active-reactive cross-compensation coefficient is preferably in the range of 0.05-0.2, and is used when the reactive power change rate is detected. When the threshold is exceeded, and the specific value of the threshold is set by the operator, a compensation amount is injected into the active current command. ,in The active-reactive cross-compensation coefficient is preferably in the range of 0.05-0.2. The cross-feedforward compensation is added to the generated current command to obtain... and ,in This represents the active current component of primary frequency modulation. It represents the reactive current component of voltage regulation and performs priority coordination processing according to the corrected instructions.

[0014] This invention provides a comprehensive device for the coordinated management of primary frequency regulation and power quality. Compared with existing technologies, it has the following advantages: This invention integrates primary frequency regulation, reactive power compensation, harmonic suppression, and three-phase imbalance control into a single integrated system, replacing multiple separate devices such as traditional energy storage coordinator controller + SVG + APF. This reduces hardware procurement costs, installation space requirements, and operation and maintenance management burden. At the same time, the unified control architecture eliminates cross-system communication delays, shortens the total response time from frequency detection to power output, and improves the pass rate of primary frequency regulation.

[0015] This invention sets fixed priorities for primary frequency regulation, voltage regulation, and harmonic compensation, and uses a graded limiting method for dynamic capacity allocation. When the total command exceeds the converter capacity, low-priority tasks are automatically derated or withdrawn, ensuring that the primary frequency regulation function is always fully guaranteed in emergency grid frequency conditions. At the same time, the reduction coefficient is rapidly iterated using a binary method and smoothed through a first-order low-pass filter to avoid oscillations caused by sudden command changes.

[0016] This invention adds a bidirectional cross-feedforward channel to the power outer loop. When the active power changes rapidly, a compensation amount is injected into the reactive current; when the reactive power changes rapidly, a compensation amount is injected into the active current. This mechanism effectively counteracts the voltage disturbance caused by the line resistance of the active power regulation and the frequency disturbance caused by the line reactance of the reactive power regulation. At the same time, the invention uses a multi-synchronous rotating coordinate system transformation method to extract characteristic subharmonics and negative sequence components, and utilizes a high-bandwidth proportional resonant current inner loop to achieve zero steady-state error tracking. Compared with conventional PI controllers, the PR controller's gain for harmonics tends to infinity at the resonant frequency, which can effectively suppress each harmonic and reduce the total harmonic distortion rate of the current. Attached Figure Description

[0017] Figure 1 This is a system block diagram of the integrated device for primary frequency regulation and power quality management according to the present invention. Detailed Implementation

[0018] 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, and 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.

[0019] First Embodiment Please see Figure 1 This application provides a comprehensive device for the coordinated management of primary frequency regulation and power quality, including a sampling and detection module. This module is used to collect the three-phase voltage and three-phase current at the grid connection point in real time, and to perform frequency and active power state detection, voltage and reactive power state detection, and harmonic and imbalance detection. At the same time, the detection results are transmitted to the multi-target current command generation module. The multi-target current command generation module is used to generate three current command components in parallel in a unified dq rotating coordinate system based on the detection results. These components include the primary frequency regulation active current component, the voltage regulation reactive current component, and the harmonic compensation current component. The three current command components are then transmitted to the priority coordination and dynamic limiting module. Priority coordination and dynamic limiting module: This module is used to dynamically coordinate current commands based on set priorities. The first priority is the active current component of primary frequency regulation, the second priority is the reactive current component of voltage regulation, and the third priority is the harmonic compensation current component. It generates coordination information and transmits it to the high-bandwidth current inner loop control module. A high-bandwidth current inner loop control module is used to input the total current command after priority arbitration into the current inner loop controller for tracking. The current inner loop adopts a proportional resonant controller. The active-reactive dynamic decoupling control module is used to perform decoupling control based on the current inner loop tracking control. In the current inner loop, the voltage equation of the converter in the dq synchronous rotating coordinate system is established. The feedforward compensation term is superimposed on the original current inner loop output to obtain the actual output voltage command. Cross feedforward compensation is introduced in the power outer loop, and the compensation amount is superimposed on the current command for correction and priority coordination.

[0020] Second Embodiment As a second embodiment of the present invention, it is implemented based on the first embodiment, and the difference from the first embodiment is as follows: The specific implementation process of the sampling and detection module is as follows: The controller collects the three-phase voltage and three-phase current at the grid connection point in real time at a sampling frequency of not less than 10kHz, and performs frequency and active power state detection, voltage and reactive power state detection, and harmonic and imbalance detection. The frequency and active power state detection is as follows: Simultaneously, the frequency f of the fundamental positive sequence component is extracted from the three-phase voltage, and the frequency deviation is calculated. ,in The rated frequency; Voltage and reactive power status detection includes: according to the formula The voltage deviation is calculated, where Rated voltage; Harmonic and imbalance detection includes: calculating the required reactive power Q of the system through instantaneous reactive power theory, specifically... ,in and This represents the voltage components along the a-axis and b-axis in a three-phase voltage. and For three-phase current in and The phase angle of the fundamental positive sequence component is obtained through a phase-locked loop, and the three-phase current is transformed into the dq synchronous rotating coordinate system via Park transform to obtain the fundamental active current. and fundamental reactive current To extract specific harmonics, rotating coordinate systems corresponding to the harmonic orders are established. After low-pass filtering, the dq component of the harmonic current is obtained. The negative sequence current component is extracted by the negative sequence synchronous rotating coordinate system. The extracted harmonics and negative sequence components are inverted to obtain the harmonic current command to be compensated.

[0021] The specific implementation process of the multi-target current command generation module is as follows: Based on the different detection results obtained, three current command components are generated in parallel under a unified dq rotating coordinate system. Specifically, these include the primary frequency modulation active current component, the voltage regulation reactive current component, and the harmonic compensation current component. The generation of the primary frequency modulation active current component is as follows: According to frequency deviation Calculate active power regulation Its calculation formula is ,in The active power-frequency droop factor is... This is the virtual inertia coefficient; When the State of Charge (SOC) is higher than the upper threshold, the forward charging power command is corrected in reverse; when the SOC is lower than the lower threshold, the reverse discharging power command is corrected in reverse, resulting in the corrected active power regulation. Next, adjust the active power. The conversion formula for active current command is as follows: ,in Represents the d-axis voltage component; The reactive current component of voltage regulation is generated as follows: based on the voltage deviation. The reactive power demand Q is used to generate a reactive current command through reactive-voltage droop control, specifically according to the formula. The amount of reactive power that needs to be adjusted is calculated. ,in The reactive power-frequency droop factor; When the system power factor is detected to be lower than the set value, reactive power output is automatically increased until the power factor recovers to the target range, at which point the final reactive power adjustment command is issued. The reactive power regulation is obtained by adding the voltage droop control quantity and the power factor adjustment quantity, converting the reactive power regulation quantity into a q-axis reactive current command, according to the calculation formula. The voltage regulation reactive current component was calculated. , Represents the q-axis voltage component; The harmonic compensation current component is generated by inverting the extracted harmonics and negative sequence components to generate the compensation current command. .

[0022] Third Embodiment As a third embodiment of the present invention, it is implemented based on the second embodiment, and the difference from the second embodiment is as follows: The specific implementation process of the priority coordination and dynamic limiting module is as follows: Based on the calculated multi-target current commands, the priority of the current commands is dynamically coordinated. Specifically, the first priority is the primary frequency regulation active current component, the second priority is the voltage regulation reactive current component, and the third priority is the harmonic compensation current component. The rated apparent power capacity of the converter is set to... The current capacity used for active power output is The remaining capacity is When the apparent power required by the total current command does not exceed At that time, the three instructions are directly superimposed. Receive total current command when the apparent power required by the total current command exceeds At that time, a tiered limiting method is used to reduce the amplitude of lower priority instructions in order of priority. The specific limiting method is as follows: Level 1: Compensate for the third-priority harmonic current component. Multiply by a reduction factor and recalculate Obtain the corrected remaining capacity and with If a comparison is made, Not exceeding Then the reduction coefficient is fixed. The first and second priorities remain unchanged; Level 2: If the reduction coefficient is... After dropping to 0 Still more Then, the second priority command is further reduced, and the voltage regulation reactive current component of the second priority is reduced. Multiply by a coefficient Recalculate; at this point, the third priority has completely exited. Level 3: If If the load remains at 0, the controller will automatically trigger overload protection, temporarily reducing the amplitude of the first priority command to within the allowable range, and simultaneously sending an alarm signal to the upper-level system. When detected Three consecutive cycles below At this time, the controller gradually restores the reduced low-priority instructions, first restoring the second priority, and then restoring the third priority after stabilization; The specific implementation process of the high-bandwidth current inner loop control module is as follows: the total current command after priority arbitration is... A high-bandwidth current inner-loop controller is used for tracking. The current inner loop employs a proportional-resonant controller with the following transfer function: ,in For proportional gain, the specific calculation formula is as follows: Where L is the AC side filter inductance of the converter. For the switching cycle, Let H be the damping ratio, and H be the set of harmonic orders that need to be compensated. Let h be the resonant gain of the h-th resonant term. The resonant bandwidth is typically taken as 5-10 rad / s. The switching frequency is set to above 10kHz to ensure that the tracking bandwidth of the current loop can simultaneously cover the fundamental frequency and the frequency components of up to dozens of harmonics.

[0023] The specific implementation process of the active-reactive dynamic decoupling control module is as follows: Based on the current inner-loop tracking control, active-reactive dynamic decoupling control is performed. First, the controller establishes the voltage equation of the converter in the dq synchronous rotating coordinate system. and ,in and For cross-coupling terms, and As a resistance voltage drop term, the controller adds a feedforward compensation term to the original inner current loop output, so that the actual output voltage command of the converter is... and ,in and This refers to the adjustment amount generated by the inner loop current controller based on the current deviation. This refers to the real-time output angular frequency of the power grid from the phase-locked loop. After the current inner loop is decoupled, cross-feedforward compensation is introduced into the power outer loop. When the active power change rate is detected... When the threshold is exceeded, a compensation amount is injected into the reactive current command. ,in The active-reactive cross-compensation coefficient is preferably in the range of 0.05-0.2, and is used when the reactive power change rate is detected. When the threshold is exceeded, and the specific value of the threshold is set by the operator, a compensation amount is injected into the active current command. ,in The active-reactive cross-compensation coefficient is preferably in the range of 0.05-0.2. The cross-feedforward compensation is added to the generated current command to obtain... and ,in This represents the active current component of primary frequency modulation. It represents the reactive current component of voltage regulation and performs priority coordination processing according to the corrected instructions.

[0024] Fourth embodiment As a fourth embodiment of the present invention, the focus is on combining the implementation processes of all the above embodiments.

[0025] Some of the data in the above formulas are numerical calculations with dimensions removed, and the contents not described in detail in this specification are all prior art known to those skilled in the art.

[0026] The above embodiments are only used to illustrate the technical methods of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical methods of the present invention without departing from the spirit and scope of the technical methods of the present invention.

Claims

1. A comprehensive device for the coordinated management of primary frequency regulation and power quality, characterized in that, include: The sampling and detection module is used to collect the three-phase voltage and three-phase current at the grid connection point in real time, and to perform frequency and active power state detection, voltage and reactive power state detection, and harmonic and imbalance detection. At the same time, the detection results are transmitted to the multi-target current command generation module. The multi-target current command generation module generates three current command components in parallel under a unified dq rotating coordinate system based on the detection results. These components include the primary frequency regulation active current component, the voltage regulation reactive current component, and the harmonic compensation current component. The module then transmits the three current command components to the priority coordination and dynamic limiting module. Priority coordination and dynamic limiting module: This module is used to dynamically coordinate current commands based on set priorities. The first priority is the active current component of primary frequency regulation, the second priority is the reactive current component of voltage regulation, and the third priority is the harmonic compensation current component. It generates coordination information and transmits it to the high-bandwidth current inner loop control module. A high-bandwidth current inner loop control module is used to input the total current command after priority arbitration into the current inner loop controller for tracking. The current inner loop adopts a proportional resonant controller. The active-reactive dynamic decoupling control module is used to perform decoupling control based on the current inner loop tracking control. In the current inner loop, the voltage equation of the converter in the dq synchronous rotating coordinate system is established. The feedforward compensation term is superimposed on the original current inner loop output to obtain the actual output voltage command. Cross feedforward compensation is introduced in the power outer loop, and the compensation amount is superimposed on the current command for correction and priority coordination.

2. The integrated device for coordinated management of primary frequency regulation and power quality according to claim 1, characterized in that, The sampling and detection module performs frequency and active power state detection, voltage and reactive power state detection, and harmonic and imbalance detection in the following ways: Frequency and active power status detection: Extract the frequency f of the fundamental positive sequence component from the three-phase voltage and calculate the frequency deviation. ,in The rated frequency; Voltage and reactive power status detection includes: according to the formula The voltage deviation is calculated, where Rated voltage; Harmonic and imbalance detection includes: calculating the required reactive power Q of the system through instantaneous reactive power theory, specifically... ,in and This represents the voltage components along the a-axis and b-axis in a three-phase voltage. and For three-phase current in and The phase angle of the fundamental positive sequence component is obtained through a phase-locked loop, and the three-phase current is transformed into the dq synchronous rotating coordinate system via Park transform to obtain the fundamental active current. and fundamental reactive current To extract specific harmonics, a rotating coordinate system corresponding to the harmonic order is established. After low-pass filtering, the dq component of the harmonic current is obtained. The negative sequence current component is extracted by the negative sequence synchronous rotating coordinate system. The extracted harmonics and negative sequence components are inverted to obtain the harmonic current command to be compensated.

3. The integrated device for coordinated management of primary frequency regulation and power quality according to claim 1, characterized in that, The generation of the primary frequency-modulated active current component is as follows: According to frequency deviation Calculate active power regulation Its calculation formula is ,in The active power-frequency droop factor is... This is the virtual inertia coefficient; When the State of Charge (SOC) is higher than the upper threshold, the forward charging power command is corrected in reverse; when the SOC is lower than the lower threshold, the reverse discharging power command is corrected in reverse, resulting in the corrected active power regulation. Next, adjust the active power. The conversion formula for active current command is as follows: ,in This represents the d-axis voltage component.

4. The integrated device for coordinated management of primary frequency regulation and power quality according to claim 1, characterized in that, The generation of the voltage-regulated reactive current component and the harmonic compensation current component is as follows: The reactive current component of voltage regulation is generated as follows: based on the voltage deviation. Combined with reactive power demand Q, and the calculation formula The amount of reactive power that needs to be adjusted is calculated. ,in The reactive power-frequency droop factor; When the system power factor is detected to be lower than the set value, reactive power output is automatically increased until the power factor recovers to the target range, at which point the final reactive power adjustment command is issued. The reactive power regulation is obtained by adding the voltage droop control quantity and the power factor adjustment quantity, converting the reactive power regulation quantity into a q-axis reactive current command, according to the calculation formula. The voltage regulation reactive current component was calculated. , Represents the q-axis voltage component; The harmonic compensation current component is generated by inverting the extracted harmonics and negative sequence components to generate the compensation current command. .

5. The integrated device for coordinated management of primary frequency regulation and power quality according to claim 1, characterized in that, The priority coordination and dynamic limiting module is based on the following method for dynamically coordinating current commands according to set priorities: Set the rated apparent power capacity of the converter to be The current capacity used for active power output is The remaining capacity is When the apparent power required by the total current command does not exceed At that time, the three instructions are directly superimposed. Receive total current command when the apparent power required by the total current command exceeds At that time, a graded amplitude limiting method is used to reduce the amplitude of lower priority instructions in order of priority.

6. The integrated device for coordinated management of primary frequency regulation and power quality according to claim 5, characterized in that, The method of using graded amplitude limiting to sequentially reduce the amplitude of lower priority instructions according to priority is as follows: The third priority harmonic compensation current component Multiply by a reduction factor and recalculate Obtain the corrected remaining capacity and with If a comparison is made, Not exceeding Then the reduction coefficient is fixed. The first and second priorities remain unchanged; If the reduction coefficient is After dropping to 0 Still more Then, the second priority command is further reduced, and the voltage regulation reactive current component of the second priority is reduced. Multiply by a coefficient Recalculate; like If the load remains at 0, the controller will automatically trigger overload protection, temporarily reducing the amplitude of the first priority command to within the allowable range, and simultaneously sending an alarm signal to the upper-level system. When detected Three consecutive cycles below At this time, the controller gradually restores the reduced low-priority instructions, first restoring the second priority, and then restoring the third priority after stabilization.

7. The integrated device for coordinated management of primary frequency regulation and power quality according to claim 1, characterized in that, The proportional resonant controller includes: Its transfer function is ,in For proportional gain, the specific calculation formula is as follows: Where L is the AC side filter inductance of the converter. For the switching cycle, Let H be the damping ratio, and H be the set of harmonic orders that need to be compensated. Let h be the resonant gain of the h-th resonant term. For the resonant bandwidth, ω is the fundamental angular frequency.

8. The integrated device for coordinated management of primary frequency regulation and power quality according to claim 1, characterized in that, The active-reactive dynamic decoupling control module performs decoupling control based on the current inner-loop tracking control in the following manner: The controller establishes the voltage equations of the converter in the dq synchronous rotating coordinate system, specifically... and ,in and For cross-coupling terms, and As a resistance voltage drop term, the controller adds a feedforward compensation term to the original inner current loop output, so that the actual output voltage command of the converter is... and ,in and This refers to the adjustment amount generated by the inner loop current controller based on the current deviation. The grid angular frequency is output in real time by the phase-locked loop. After the decoupling of the inner current loop is completed, cross-feedforward compensation is introduced in the outer power loop.

9. The integrated device for coordinated management of primary frequency regulation and power quality according to claim 8, characterized in that, The method of introducing cross-feedforward compensation in the power outer loop is as follows: When the rate of change of active power is detected When the threshold is exceeded, a compensation amount is injected into the reactive current command. ,in This is the active-reactive cross-compensation coefficient, which is used when the reactive power change rate is detected. When the threshold is exceeded, and the specific value of the threshold is set by the operator, a compensation amount is injected into the active current command. ,in This is the active-reactive cross-compensation coefficient; The cross-feedforward compensation is added to the generated current command to obtain... and ,in This represents the active current component of primary frequency modulation. It represents the reactive current component of voltage regulation and performs priority coordination processing according to the corrected instructions.

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