Static VAR generator control method and system

Abstract

The present invention discloses a static VAR generator control method and system, which can quickly respond to changes in grid voltage and maintain the system voltage within a set range by dynamically adjusting reactive power output. This is especially important for long-distance transmission lines and heavily loaded areas. When the system is subject to large disturbances, reactive power can be quickly provided or absorbed to prevent voltage collapse and ensure stable operation of the system.

Description

Technical Field

[0001] The present invention relates to the field of electromechanical equipment, and in particular to a static VAR generator control method and system. Background Art

[0002] A static VAR generator connects a self-commutated bridge circuit to the grid through a reactor or directly in parallel, adjusts the phase and amplitude of the output voltage on the AC side of the bridge circuit, or directly controls its AC side current, so that the circuit absorbs or emits reactive power that meets the requirements, thereby achieving the purpose of dynamic reactive power compensation.

[0003] Static VAR generators (SVARs) can be used to compensate for reactive power, improve power factor, and optimize power quality. However, when a grid voltage sag occurs, the SVAR generator will disconnect from the grid and cease operation, waiting for the grid to recover before restarting. This can cause grid fluctuations and degrade the user experience.

[0004] In summary, a static VAR generator control method and system are needed to address the deficiencies in the prior art. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention provides a static VAR generator control method and system, aiming to solve the above problems.

[0006] To achieve the above object, the present invention provides the following technical solution: a static VAR generator control method and system, comprising the following steps:

[0007] Step S1: Set and measure reactive power, set the required reactive power as Qref,

[0008] Step S2: Reactive power measurement, measuring the actual three-phase current and voltage through current sensors and voltage sensors;

[0009] Step S3: Reactive power calculation, calculating the actual reactive power Q based on the measured current and voltage, and calculating the error between the required reactive power and the actual reactive power;

[0010] Step S4: converting the reactive power error into a current reference value Iref, and decomposing the current reference value Iref into d-axis and q-axis components;

[0011] Step S5: Convert the circuit errors of the d-axis and q-axis into PWM modulation signals Ud and Uq;

[0012] Step S6: Convert the d-axis and q-axis control signals Ud and Uq into three-phase PWM modulation signals to control the power electronic switches of the static VAR generator, and adjust the output power of the static VAR generator by adjusting the amplitude and phase of the output current of the static VAR generator.

[0013] Optionally, the reactive power calculation and error calculation in step S3 are performed in the following manner:

[0014] The reactive power Q is calculated by multiplying the conversion factor by the peak voltage and current values ​​and the sine value of the phase difference between the current and the voltage.

[0015] The reactive power error is calculated as the difference between the required reactive power Qref and the reactive power Q.

[0016] Optionally, the reactive power error in step S4 is converted into a current reference value Iref in the following manner:

[0017] The conversion is performed by multiplying the proportional gain coefficient by the power-free error and adding the integral gain coefficient by the integral term of the power error from the initial time 0 to the current time t.

[0018] Optionally, in step S4, the current reference value Iref is decomposed into d-axis and q-axis components in the following manner:

[0019] d-axis: Iref d By the current reference value Iref and the phase angle Calculate the product of the cosine values ​​of

[0020] q-axis: Iref q By the current reference value Iref and the phase angle Calculates the product of the sines of .

[0021] Optionally, the circuit errors of the d-axis and the q-axis in step S5 are converted into PWM modulation signals Ud and Uq in the following manner:

[0022] Modulation signal Ud: converted by multiplying the d-axis proportional gain by the product of the d-axis component and the actual d-axis current difference, plus the integral gain and the integral term of the d-axis component and the actual d-axis current difference from the initial time 0 to the current time t;

[0023] Modulation signal Uq: converted by the product of the q-axis proportional gain and the difference between the q-axis component and the actual q-axis current, plus the integral gain and the integral term of the difference between the q-axis component and the actual q-axis current from the initial time 0 to the current time t.

[0024] Optionally, in step S6, the control signals Ud and Uq are converted into three-phase PWM modulation signals in the following manner:

[0025] Step S61: Selecting a suitable inverter model and decomposing the inverter voltage into d-axis voltage and q-axis voltage;

[0026] Step S62: Convert the control signals Ud and Uq into three-phase PWM modulation signals ua, ub and uc through the inverter's inverse Park transformation.

[0027] Optionally, the power electronic switch of the static VAR generator controlled in step S6 is adjusted in the following manner:

[0028] Step S63: inputting the generated three-phase PWM signal into the drive circuit of the inverter;

[0029] Step S64: The driving circuit converts the PWM signal into a driving signal to control the on and off of the IGBTs;

[0030] Step S65: The IGBTs are switched rapidly according to the received driving signal to adjust the amplitude and phase of the output current of the static VAR generator.

[0031] Optionally, in step S65,

[0032] The adjustment amplitude is:

[0033] The duty cycle of the PWM signal is adjusted by a PI controller to adjust the amplitude of the output current of the static VAR generator so that the amplitude of the output current of the static VAR generator tracks the reference value Iref;

[0034] Adjust the phase to:

[0035] The PI controller adjusts the phase angle of the PWM signal to adjust and change the phase of the static VAR generator output current relative to the grid voltage, so that the reactive power Q output by the static VAR generator tracks the reference value Qref.

[0036] Optionally, the PWM modulation in step S6 includes sinusoidal pulse width modulation and space vector modulation.

[0037] Sinusoidal pulse width modulation is:

[0038] Select appropriate triangular carrier frequency and amplitude, compare each phase voltage with the triangular carrier signal, and output a high level when the phase voltage is greater than the triangular carrier; output a low level when the phase voltage is less than the triangular carrier.

[0039] Space vector modulation is:

[0040] Determine the sector where the current voltage vector is located, calculate the action time of each basic voltage vector, generate the corresponding PWM signal, and control the switching state in the inverter.

[0041] A static VAR generator control system adopts the static VAR generator control method, including a main circuit unit, a control unit, a detection unit, a protection unit and a human-computer interaction unit.

[0042] The main circuit unit is used to convert direct current into alternating current with the same frequency as the power grid;

[0043] The control unit is responsible for detecting the state of the power grid, calculating the amount of reactive power that needs to be emitted or absorbed, and adjusting the working state of the power electronic switches in the circuit;

[0044] The detection unit is used to collect relevant parameters of the power grid in real time and transmit the parameters to the control unit;

[0045] A protection unit for ensuring safe operation of the static VAR generator and the connected power grid;

[0046] The human-machine interaction unit is used to provide an interactive interface between the operator and the static VAR generator.

[0047] Beneficial effects of the present invention:

[0048] 1. The present invention can quickly respond to changes in grid voltage and maintain the system voltage within a set range by dynamically adjusting reactive power output. This is particularly important for long-distance transmission lines and heavily loaded areas. When the system is subject to large disturbances, reactive power can be quickly provided or absorbed to prevent voltage collapse and ensure stable system operation.

[0049] 2. The present invention can smooth voltage fluctuations, reduce voltage swells and dips, improve power quality, and has a filtering function. It can reduce the harmonic content in the system, reduce the impact of harmonics on equipment, compensate for negative sequence current, and reduce the impact of unbalanced loads on the system.

[0050] 3. In the present invention, by compensating for reactive power, the reactive power flow on the transmission line can be reduced, the transmission loss can be reduced, the overall efficiency of the system can be improved, the utilization rate of equipment such as transformers and cables can be improved, the equipment life can be extended, and the maintenance cost can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 The present invention is a flow chart of a method.

[0052] Figure 2 This is a system structure diagram of the present invention. DETAILED DESCRIPTION

[0053] In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0054] like Figure 1 As shown, a static VAR generator control method includes the following contents:

[0055] Step S1: Set and measure reactive power, set the required reactive power as Qref,

[0056] Step S2: Reactive power measurement, measuring the actual three-phase current and voltage through current sensors and voltage sensors;

[0057] Step S3: Reactive power calculation, calculating the actual reactive power Q based on the measured current and voltage, and calculating the error between the required reactive power and the actual reactive power;

[0058] Step S4: converting the reactive power error into a current reference value Iref, and decomposing the current reference value Iref into d-axis and q-axis components;

[0059] Step S5: Convert the circuit errors of the d-axis and q-axis into PWM modulation signals Ud and Uq;

[0060] Step S6: Convert the d-axis and q-axis control signals Ud and Uq into three-phase PWM modulation signals to control the power electronic switches of the static VAR generator, and adjust the output power of the static VAR generator by adjusting the amplitude and phase of the output current of the static VAR generator.

[0061] Assume that the static VAR generator is connected to a three-phase balanced AC grid. The grid voltage is expressed in vector form as V=Vm∠0︒, and the required reactive power is Qref.

[0062] The reactive power Q can be calculated as follows:

[0063] , where Vm is the peak voltage, Im is the peak current, and θ is the phase difference between current and voltage;

[0064] If the goal is to increase reactive power output (i.e., the SVG operates as a reactive power source), the positive value of sin(θ) needs to be increased. If the goal is to reduce reactive power output or absorb reactive power (i.e., the SVG operates as a reactive load), sin(θ) needs to be reduced or made negative.

[0065] The reactive power error is: eQ=Qref-Q.

[0066] Control strategy:

[0067] The outer loop first determines the required reactive power, Qref. Based on Qref and the actual measured reactive power, Q, the error, eQ = Qref - Q, is calculated. This error is then converted to a current reference, Iref, using a PI controller or other type of controller.

[0068] The current reference value of the outer loop control is calculated as:

[0069] ,

[0070] Where, Iref: This is the current reference value, which is the target current value obtained after processing by the PI controller and is used to guide the SVG on how to adjust its output current to match the desired reactive power demand.

[0071] Kp: Proportional gain coefficient. This is a constant that determines the degree to which the current reactive power error, eQ, affects the current reference. Proportional gain directly affects the control system's response speed.

[0072] eQ: Reactive power error, defined as the difference between the set reactive power reference value Qref and the actual measured reactive power Q, that is, eQ = Qref - Q. This error reflects the gap between the actual performance of the SVG in the current state and its expected target.

[0073] Ki: The integral gain factor, a constant that determines the impact of the accumulated reactive power error over all past time points on the current reference. The integral term eliminates steady-state errors, allowing the system to stabilize over long timescales.

[0074] This is an integral term of the reactive power error eQ from the initial time 0 to the current time t, which represents the cumulative effect of the reactive power error in the entire process from the beginning to now.

[0075] The current reference value Iref is decomposed into d-axis and q-axis components in the following way:

[0076] ,

[0077] ,

[0078] Where, is the phase angle, usually set to 0 degrees.

[0079] In the inner loop control, another PI controller is used to convert the current reference value 𝐼ref into a PWM modulation signal to control the power electronic switches in the SVG. This step ensures that the current output by the SVG can quickly and accurately track the reference value.

[0080] The circuit errors of the d-axis and q-axis are converted into PWM modulation signals Ud and Uq in the following way:

[0081] ,

[0082] ,

[0083] Where K p,d is the d-axis proportional gain, K i,d is the integral gain, K p,q is the q-axis proportional gain, K i,q is the q-axis integral gain, I d is the actual d-axis current, I q is the actual q-axis current.

[0084] Converting the d-axis and q-axis control signals Ud and Uq into three-phase PWM modulation signals to control the power electronic switches in the SVG is an important step in the SVG control system. This process usually involves the following steps:

[0085] 1. Inverter model

[0086] Assuming that the SVG uses a three-phase voltage source inverter, its output voltage can be controlled by PWM modulation. The output voltage of the inverter can be expressed as:

[0087] V=Vdad+Vqaq,

[0088] Where ad and aq are the unit vectors of the d-axis and q-axis, corresponding to the direct and quadrature axis directions, respectively.

[0089] 2. Coordinate Transformation

[0090] The d-axis and q-axis control signals Ud and Uq are converted into voltage signals ua, ub, and uc in a three-phase stationary coordinate system. This is usually achieved through an inverse Park transform (also known as a dq0 to abc transform).

[0091] Inverse Park transform formula:

[0092] ,

[0093] Where θ is the voltage phase angle.

[0094] Based on the generated PWM signal, the output power of the static VAR generator (SVG) is adjusted by adjusting the amplitude and phase of the SVG output current. The specific steps are as follows:

[0095] 1. Generate PWM signal

[0096] First, three-phase PWM signals are generated according to the method described above. These signals will be used to control the power electronic switches (such as IGBTs) in the SVG.

[0097] 2. Control power electronic switches

[0098] The generated PWM signal is applied to the power electronic switches in the SVG. The specific steps are as follows:

[0099] PWM signal input: The generated three-phase PWM signals pwma, pwmb, and pwmc are input into the drive circuit of the inverter.

[0100] Driver circuit: The driver circuit converts the PWM signal into appropriate drive signals to control the on and off of the IGBTs. These drive signals are usually high-voltage pulses that can quickly switch the IGBTs on and off.

[0101] IGBTs control: IGBTs switch rapidly according to the received drive signal, thereby changing the amplitude and phase of the SVG output current.

[0102] 3. Adjust the amplitude and phase of the output current

[0103] By controlling the switching state of IGBTs, the amplitude and phase of the SVG output current can be adjusted, thereby regulating the output power of the SVG.

[0104] Adjust the amplitude

[0105] PWM duty cycle: The duty cycle of the PWM signal determines the amplitude of the inverter output voltage. By adjusting the duty cycle of the PWM signal, the amplitude of the SVG output current can be changed.

[0106] Control strategy: In the inner loop control, the duty cycle of the PWM signal is adjusted through the PI controller so that the amplitude of the SVG output current tracks the reference value Iref.

[0107] Adjust Phase

[0108] Phase angle: By adjusting the phase angle of the PWM signal, the phase of the SVG output current relative to the grid voltage can be changed.

[0109] Control strategy: In the outer loop control, the PI controller is used to adjust the phase angle of the PWM signal so that the reactive power Q output by the SVG tracks the reference value Qref.

[0110] 4. Real-time monitoring and feedback

[0111] To ensure that the SVG's output current accurately tracks the reference value, real-time monitoring and feedback are required:

[0112] Current sensor: The current sensor installed at the output end of the SVG measures the output current ia, ib, ic in real time.

[0113] Voltage sensor: The voltage sensor installed on the grid side measures the grid voltage va, vb, vc in real time.

[0114] Data acquisition: Transmits the measured current and voltage data to the control unit.

[0115] Error calculation: The control unit calculates the error between the actual output current and the reference value and adjusts the PWM signal according to the error.

[0116] 5. Dynamic Adjustment

[0117] In actual operation, grid conditions may change, so it is necessary to dynamically adjust the control parameters:

[0118] Adaptive control: Dynamically adjust the parameters of the PI controller according to changes in grid conditions to maintain system stability and response speed.

[0119] Fault detection and protection: Real-time monitoring of system status, detection of faults such as overvoltage and overcurrent, and implementation of protective measures to ensure safe operation of the SVG.

[0120] PWM modulation

[0121] The three-phase voltage signals ua, ub, and uc are converted into PWM signals to control the power electronic switches (such as IGBTs) in the inverter. Common PWM modulation methods include sinusoidal pulse width modulation (SPWM) and space vector modulation (SVPWM).

[0122] Sinusoidal Pulse Width Modulation

[0123] In SPWM, each phase voltage ua, ub, uc is compared with a triangular carrier signal to generate the corresponding PWM signal. The specific steps are as follows:

[0124] Generate a triangular carrier signal: Select an appropriate triangular carrier frequency and amplitude.

[0125] Comparison: Compare each phase voltage ua, ub, uc with the triangular carrier signal.

[0126] Generate PWM signal: when the phase voltage is greater than the triangular carrier, the output is high level; when the phase voltage is less than the triangular carrier, the output is low level.

[0127] Space Vector Modulation

[0128] SVPWM is a more efficient modulation method that can improve inverter utilization and output waveform quality. The specific steps are as follows:

[0129] Calculate sector: Determine the sector where the current voltage vector is located.

[0130] Calculate the action time: Calculate the action time of each basic voltage vector based on Ud and Uq.

[0131] Generate PWM signal: Generate corresponding PWM signal according to the calculated action time to control the switching state in the inverter.

[0132] 4. Control inverter

[0133] Based on the generated PWM signal, the power electronic switches (such as IGBTs) in the inverter are controlled to adjust the amplitude and phase of the SVG output current so that it tracks the reference value.

[0134] like Figure 2 As shown, a static VAR generator control system includes the following contents:

[0135] The main circuit unit, consisting of a power electronic converter, is the core of the SVG, responsible for converting DC power to AC power with the same frequency as the grid, and vice versa. Depending on the application scenario, the main circuit can adopt different topologies, such as two-level, three-level, or multiplexed structures.

[0136] The control unit monitors grid conditions (such as voltage and current) and calculates the amount of reactive power required to be generated or absorbed. This information then generates corresponding control signals to adjust the operating conditions of the power electronic devices in the main circuit. Control strategies can be highly complex, including but not limited to instantaneous value control and predictive control.

[0137] Detection unit: This unit collects grid-related parameters, such as voltage and current, in real time and transmits this information to the control unit. Accurate and reliable detection is crucial for achieving precise control.

[0138] Protection unit: Ensures the safe operation of the SVG and the grid it is connected to. When an abnormal situation is detected (such as overvoltage, undervoltage, overcurrent, etc.), timely protection measures can be taken.

[0139] Human-machine interface: Provides an interactive interface between the operator and the SVG, making it easy to monitor the operating status of the SVG and make necessary settings adjustments.

[0140] The present invention can bring the following effects:

[0141] Improve voltage stability

[0142] Voltage Regulation: SVGs can quickly respond to grid voltage changes by dynamically adjusting reactive power output to maintain system voltage within a set range. This is particularly important for long-distance transmission lines and heavily loaded areas.

[0143] Preventing voltage collapse: When the system is subject to a major disturbance, SVG can quickly provide or absorb reactive power to prevent voltage collapse and ensure stable system operation.

[0144] Improve power quality

[0145] Reduce voltage fluctuations: SVG can smooth voltage fluctuations, reduce voltage swells and sags, and improve power quality.

[0146] Harmonic suppression: SVG has a filtering function that can reduce the harmonic content in the system and reduce the impact of harmonics on equipment.

[0147] Reducing negative sequence components: SVG can compensate for negative sequence current, reduce the impact of unbalanced loads on the system, and improve power supply quality.

[0148] Improve system efficiency

[0149] Reduce transmission losses: By compensating for reactive power, SVG can reduce the flow of reactive power on transmission lines, lower transmission losses, and improve the overall efficiency of the system.

[0150] Optimize equipment utilization: SVG can improve the utilization of equipment such as transformers and cables, extend equipment life, and reduce maintenance costs.

[0151] Enhance system reliability

[0152] Fast response: SVG has fast response capabilities and can complete reactive power regulation within milliseconds, effectively dealing with transient disturbances in the system.

[0153] Fault recovery: After a system fault occurs, SVG can quickly restore reactive power balance, speed up system recovery, and reduce the duration and scope of power outages.

[0154] Supporting renewable energy access

[0155] Smoothing fluctuations: SVG can smooth the output fluctuations of renewable energy (such as wind and solar energy) to ensure the stable operation of the power grid.

[0156] Improve grid connection capability: Through reactive power compensation, SVG can improve the grid connection capability of distributed power sources and promote the large-scale integration of renewable energy.

[0157] Reduce operating costs

[0158] Reduce costs: By improving power quality and voltage stability, SVG can help users avoid costs caused by power quality issues.

[0159] Energy saving and consumption reduction: reduce the transmission loss of reactive power, reduce system energy consumption, and save operating costs.

[0160] Improve user satisfaction.

[0161] Stable power supply: SVG can ensure that users receive stable voltage and high-quality electricity, improving user satisfaction and trust.

[0162] Reduce equipment damage: By improving power quality, the risk of equipment damage due to voltage fluctuations and harmonics is reduced, and the service life of equipment is extended.

[0163] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A static VAR generator control method, characterized in that: The following steps are involved: Step S1: Set and measure reactive power, set the required reactive power as Qref, Step S2: Reactive power measurement, measuring the actual three-phase current and voltage through current sensors and voltage sensors; Step S3: Reactive power calculation, calculating the actual reactive power Q based on the measured current and voltage, and calculating the error between the required reactive power and the actual reactive power; Step S4: converting the reactive power error into a current reference value Iref, and decomposing the current reference value Iref into d-axis and q-axis components; Step S5: Convert the circuit errors of the d-axis and q-axis into PWM modulation signals Ud and Uq; Step S6: Convert the d-axis and q-axis control signals Ud and Uq into three-phase PWM modulation signals to control the power electronic switches of the static VAR generator, and adjust the output power of the static VAR generator by adjusting the amplitude and phase of the output current of the static VAR generator.

2. The static VAR generator control method according to claim 1, characterized in that: The reactive power calculation and error calculation in step S3 are performed in the following manner: The reactive power Q is calculated by multiplying the conversion factor by the peak voltage and current values ​​and the sine value of the phase difference between the current and the voltage. The reactive power error is calculated as the difference between the required reactive power Qref and the reactive power Q.

3. The static VAR generator control method according to claim 2, characterized in that: In step S4, the reactive power error is converted into a current reference value Iref in the following manner: The conversion is performed by multiplying the proportional gain coefficient by the reactive power error and adding the integral gain coefficient by the integral term of the reactive power error from the initial time 0 to the current time t.

4. The static VAR generator control method according to claim 3, characterized in that: In step S4, the current reference value Iref is decomposed into d-axis and q-axis components in the following manner: d-axis: Iref d By the current reference value Iref and the phase angle Calculate the product of the cosine values ​​of q-axis: Iref q By the current reference value Iref and the phase angle Calculates the product of the sines of .

5. The static VAR generator control method according to claim 4, characterized in that: The circuit errors of the d-axis and q-axis in step S5 are converted into PWM modulation signals Ud and Uq in the following manner: Modulation signal Ud: converted by multiplying the d-axis proportional gain by the product of the d-axis component and the actual d-axis current difference, plus the integral gain and the integral term of the d-axis component and the actual d-axis current difference from the initial time 0 to the current time t; Modulation signal Uq: converted by the product of the q-axis proportional gain and the difference between the q-axis component and the actual q-axis current, plus the integral gain and the integral term of the difference between the q-axis component and the actual q-axis current from the initial time 0 to the current time t.

6. The static VAR generator control method according to claim 1, characterized in that: In step S6, the control signals Ud and Uq are converted into three-phase PWM modulation signals in the following manner: Step S61: Selecting a suitable inverter model and decomposing the inverter voltage into d-axis voltage and q-axis voltage; Step S62: Convert the control signals Ud and Uq into three-phase PWM modulation signals ua, ub and uc through the inverse Park transformation of the inverter.

7. The static VAR generator control method according to claim 6, characterized in that: The power electronic switch of the static VAR generator controlled in step S6 is adjusted in the following manner: Step S63: inputting the generated three-phase PWM signal into the drive circuit of the inverter; Step S64: The driving circuit converts the PWM signal into a driving signal to control the on and off of the IGBTs; Step S65: The IGBTs are switched rapidly according to the received driving signal to adjust the amplitude and phase of the output current of the static VAR generator.

8. The static VAR generator control method according to claim 7, characterized in that: In the step S65, The adjustment amplitude is: The duty cycle of the PWM signal is adjusted by a PI controller to adjust the amplitude of the output current of the static VAR generator so that the amplitude of the output current of the static VAR generator tracks the reference value Iref; Adjust the phase to: The PI controller adjusts the phase angle of the PWM signal to adjust and change the phase of the static VAR generator output current relative to the grid voltage, so that the reactive power Q output by the static VAR generator tracks the reference value Qref.

9. The static VAR generator control method according to claim 1, characterized in that: The PWM modulation in step S6 includes sinusoidal pulse width modulation and space vector modulation. Sinusoidal pulse width modulation is: Select appropriate triangular carrier frequency and amplitude, compare each phase voltage with the triangular carrier signal, and output a high level when the phase voltage is greater than the triangular carrier; output a low level when the phase voltage is less than the triangular carrier. Space vector modulation is: Determine the sector where the current voltage vector is located, calculate the action time of each basic voltage vector, generate the corresponding PWM signal, and control the switching state in the inverter.

10. A static VAR generator control system, using the static VAR generator control method according to claim 1, characterized in that: Including main circuit unit, control unit, detection unit, protection unit and human-computer interaction unit, The main circuit unit is used to convert direct current into alternating current with the same frequency as the power grid; The control unit is responsible for detecting the state of the power grid, calculating the amount of reactive power that needs to be emitted or absorbed, and adjusting the working state of the power electronic switches in the circuit; The detection unit is used to collect relevant parameters of the power grid in real time and transmit the parameters to the control unit; A protection unit for ensuring safe operation of the static VAR generator and the connected power grid; The human-machine interaction unit is used to provide an interactive interface between the operator and the static VAR generator.

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