Low-voltage series reactive compensation device

Abstract

The utility model discloses a low pressure series compensation device relates to the technical field of compensation circuit, including the soft start power supply circuit for controlling starting current slow rise, the surge impact is suppressed, the capacitive reactive power output for the dynamic regulation series capacitor, the low pressure reactive power compensation circuit of compensation inductive load's reactive power shortage, the voltage detection circuit for real -time tracking circuit voltage fluctuation, generates the voltage feedback signal required for compensation control. The utility model discloses through the voltage detection circuit, thereby through the accurate detection of resistance voltage dividing network and operational amplifier IC1, realizes real -time monitoring and signal conditioning to the grid voltage, ensures that compensation system can accurately obtain voltage variation information, provides reliable data support for reactive power compensation control.

Description

Technical Field

[0001] This utility model relates to the field of compensation circuit technology, specifically to a low-voltage series reactive power compensation device. Background Technology

[0002] Low-voltage series reactive power compensation (LVPC) is a method that dynamically compensates for reactive power in a low-voltage power grid by connecting capacitors in series. Its aim is to improve the power factor, reduce reactive power losses, and optimize power quality. Reactive power is mainly generated by inductive loads (such as motors and transformers). LVPC compensates for the reactive power consumed by inductive loads by adjusting the amount of series capacitors connected in real time, thereby reducing the reactive power burden on the power grid and improving the overall efficiency and stability of the power system.

[0003] When compensating for reactive power in the power grid, if changes in grid voltage cannot be monitored in real time, the compensation amount cannot be adjusted promptly according to voltage fluctuations, leading to overcompensation or undercompensation. Overcompensation causes the grid voltage to rise, potentially resulting in excessively high voltage, affecting the normal operation of electrical equipment and even damaging it. Undercompensation, on the other hand, leads to a decrease in the power factor, increases reactive power in the grid, and reduces energy efficiency. Therefore, the voltage detection circuit is crucial for ensuring the stable operation of the compensation system and accurately adjusting the compensation amount. The absence of this circuit will significantly reduce the reliability and safety of the power grid and may even lead to equipment damage. Utility Model Content

[0004] In view of the problems in the related technologies, this utility model proposes a low-voltage series reactive power compensation device to overcome the above-mentioned technical problems existing in the existing related technologies.

[0005] Therefore, the specific technical solution adopted by this utility model is as follows:

[0006] A low-voltage series reactive power compensation device, comprising:

[0007] A soft-start power supply circuit used to control the slow rise of the starting current and suppress surge impact;

[0008] A low-voltage reactive power compensation circuit used to dynamically adjust the capacitive reactive power output of series capacitors and compensate for the reactive power deficit of inductive loads.

[0009] A voltage detection circuit is used to track circuit voltage fluctuations in real time and generate the voltage feedback signal required for compensation control.

[0010] The output of the soft-start power supply circuit is electrically connected to the input of the low-voltage reactive power compensation circuit, and the output of the low-voltage reactive power compensation circuit is electrically connected to the input of the voltage detection circuit.

[0011] Furthermore, the soft-start power supply circuit includes diodes D1, D2, D3, D4, D5, and D6, transformer T1, capacitors C3 and C4, inductor L1, transistor KT1, and driver chip U1.

[0012] In this circuit, the cathode of diode D1 is connected to the cathode of diode D3 and one end of resistor R10. The anode of diode D1 is connected to the cathode of diode D2 and connected to the AC terminal. The anode of diode D2 is connected to the anode of diode D4, the second pin of driver chip U2, one end of capacitor C3, and the emitter of transistor KT1. The cathode of diode D4 is connected to the anode of diode D3 and connected to the AC terminal. The first pin of driver chip U1 is connected to the base of transistor KT1. The collector of transistor KT1 is connected to the third pin of transformer T1. The first pin of transformer T1 is connected to the other end of capacitor C3 and the other end of resistor R10. The second pin of transformer T1 is connected to the anode of diode D5. The cathode of diode D5 is connected to one end of inductor L1 and the cathode of diode D6. The other end of inductor L1 is connected to one end of capacitor C4. The other end of capacitor C4 is connected to the anode of diode D6, the fourth pin of transformer T1, and the low-voltage reactive power compensation circuit.

[0013] Furthermore, both capacitors C3 and C4 are energy storage capacitors.

[0014] Furthermore, the low-voltage reactive power compensation circuit includes resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, transistor KT3, relay switch KT2, and microcontroller U2.

[0015] In this circuit, one end of resistor R1 is connected to one end of resistor R5 and one end of capacitor C2. The other end of capacitor C2 is connected to the base of transistor KT1. The collector of transistor KT1 is connected to one end of resistor R2 and one end of capacitor C1. The other end of capacitor C1 is connected to the first pin of relay switch KT2. The second pin of relay switch KT2 is connected to one end of resistor R7. The other end of resistor R7 is connected to one end of resistor R6, the other end of resistor R1, and the soft-start power supply circuit. The other end of resistor R6 is connected to the emitter of transistor KT1. The third pin of relay switch KT2 is connected to one end of resistor R3. The other end of resistor R3 is connected to one end of resistor R8, one end of resistor R4, and one end of resistor R9. The other end of resistor R8 is connected to the other end of resistor R5. The other end of R9 is connected to the voltage detection circuit. The other end of resistor R4 is connected to microprocessor U2.

[0016] Furthermore, the voltage detection circuit includes resistors R11, R12, R13, R14, R15 and operational amplifier IC1;

[0017] In this configuration, the first pin of operational amplifier IC1 is connected to one end of resistor R11 and one end of resistor R14, with the other end of resistor R14 grounded. The second pin of operational amplifier IC1 is connected to one end of resistor R13, the third pin of operational amplifier IC1, and the other end of resistor R9. The fourth pin of operational amplifier IC1 is connected to the VCC terminal, and the fifth pin of operational amplifier IC1 is grounded. The other end of resistor R11 is connected to one end of resistor R12 and to the POWER terminal. The other end of resistor R12 is connected to the other end of resistor R13 and one end of resistor R15, with the other end of resistor R15 grounded.

[0018] Furthermore, resistor R15 is the load resistor in voltage detection circuit 3.

[0019] The beneficial effects of this utility model are as follows:

[0020] 1. This utility model, through a soft-start power supply circuit, can achieve smooth start-up and stable power supply, effectively suppress the inrush current at the moment of start-up, prevent grid voltage fluctuations, improve the safety and reliability of the system, and at the same time ensure the long-term stable operation of the compensation device, extend the equipment life, and reduce interference to the power grid and other electrical equipment.

[0021] 2. This utility model, by setting up a low-voltage reactive power compensation circuit, can monitor and automatically adjust the reactive power compensation amount in real time, accurately compensate the reactive power of inductive loads, optimize the power factor, reduce reactive power loss in the power grid, and improve power quality. At the same time, through the control of relays and transistors, it ensures efficient switching and stable operation of the circuit, ensuring the safety and long service life of the equipment.

[0022] 3. This utility model, by setting up a voltage detection circuit, achieves real-time monitoring and signal conditioning of the power grid voltage through the precise detection of the resistor voltage divider network and the operational amplifier IC1. This ensures that the compensation system can accurately obtain voltage change information, providing reliable data support for reactive power compensation control, thereby avoiding overcompensation or undercompensation, and effectively protecting the equipment from the effects of voltage fluctuations. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of a low-voltage series reactive power compensation device according to an embodiment of the present utility model.

[0025] In the picture:

[0026] 1. Soft-start power supply circuit; 2. Low-voltage reactive power compensation circuit; 3. Voltage detection circuit. Detailed Implementation

[0027] To further illustrate the various embodiments, the present invention provides accompanying drawings, which are part of the disclosure of the present invention. These drawings are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementation methods and the advantages of the present invention.

[0028] According to an embodiment of the present invention, a low-voltage series reactive power compensation device is provided.

[0029] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments, such as... Figure 1 As shown, the low-voltage series reactive power compensation device according to an embodiment of the present invention includes:

[0030] Soft-start power supply circuit 1 is used to control the slow rise of the starting current and suppress surge impact;

[0031] Low-voltage reactive power compensation circuit 2 is used to dynamically adjust the capacitive reactive power output of series capacitors and compensate for the reactive power deficit of inductive loads.

[0032] Voltage detection circuit 3 is used to track circuit voltage fluctuations in real time and generate the voltage feedback signal required for compensation control.

[0033] The output terminal of the soft-start power supply circuit 1 is electrically connected to the input terminal of the low-voltage reactive power compensation circuit 2, and the output terminal of the low-voltage reactive power compensation circuit 2 is electrically connected to the input terminal of the voltage detection circuit 3.

[0034] In one embodiment, the soft-start power supply circuit 1 includes diodes D1, D2, D3, D4, D5, and D6, transformer T1, capacitors C3 and C4, inductor L1, transistor KT1, and driver chip U1.

[0035] In this configuration, the cathode of diode D1 is connected to the cathode of diode D3 and one end of resistor R10. The anode of diode D1 is connected to the cathode of diode D2 and connected to the AC terminal. The anode of diode D2 is connected to the anode of diode D4, the second pin of driver chip U2, one end of capacitor C3, and the emitter of transistor KT1. The cathode of diode D4 is connected to the anode of diode D3 and connected to the AC terminal. The first pin of driver chip U1 is connected to the base of transistor KT1. The collector of transistor KT1 is connected to the transformer... The third pin of transformer T1 is connected to the other end of capacitor C3 and resistor R10 respectively. The second pin of transformer T1 is connected to the positive terminal of diode D5. The negative terminal of diode D5 is connected to one end of inductor L1 and the negative terminal of diode D6 respectively. The other end of inductor L1 is connected to one end of capacitor C4. The other end of capacitor C4 is connected to the positive terminal of diode D6, the fourth pin of transformer T1 and low-voltage reactive power compensation circuit 2 respectively. Both capacitors C3 and C4 are energy storage capacitors.

[0036] Specifically, the working principle of the soft-start power supply circuit 1 is as follows:

[0037] The AC power supply is converted into pulsating DC by a bridge rectifier circuit composed of diodes D1 to D4. The driver chip U1 controls the duty cycle of transistor KT1 by adjusting the base current, which gradually increases the switching frequency of the primary coil of transformer T1, indirectly regulating the voltage amplitude coupled to the secondary coil, and realizing a gradual increase in output voltage. The AC voltage output from the secondary coil is then converted into DC by a full-wave rectifier circuit composed of diodes D5 and D6. After being smoothed by an LC filter composed of inductor L1 and capacitor C4, a stable DC power supply VDC is output. At the same time, the primary side capacitor C3 and resistor R10 form an RC filter network to suppress the input surge current. Throughout the process, the driver chip U1 limits the initial excitation rate of the transformer T1 core by dynamically adjusting the switching sequence of KT1, avoiding sudden changes in the input current, and finally achieving a soft-start function, ensuring that the capacitor switching of the subsequent reactive power compensation circuit 2 is connected to the grid without impact.

[0038] In one embodiment, the low-voltage reactive power compensation circuit 2 includes resistors R1, R2, R3, R4, R5, R6, R7, R8, and R9, transistor KT3, relay switch KT2, and microcontroller U2.

[0039] In this circuit, one end of resistor R1 is connected to one end of resistor R5 and one end of capacitor C2. The other end of capacitor C2 is connected to the base of transistor KT1. The collector of transistor KT1 is connected to one end of resistor R2 and one end of capacitor C1. The other end of capacitor C1 is connected to the first pin of relay switch KT2. The second pin of relay switch KT2 is connected to one end of resistor R7. The other end of resistor R7 is connected to one end of resistor R6, the other end of resistor R1, and soft-start power supply circuit 1. The other end of resistor R6 is connected to the emitter of transistor KT1. The third pin of relay switch KT2 is connected to one end of resistor R3. The other end of resistor R3 is connected to one end of resistor R8, one end of resistor R4, and one end of resistor R9. The other end of resistor R8 is connected to the other end of resistor R5. The other end of R9 is connected to voltage detection circuit 3. The other end of resistor R4 is connected to microprocessor U2.

[0040] Specifically, the working principle of the low-voltage reactive power compensation circuit is as follows:

[0041] The microprocessor U2 receives the system voltage signal from the voltage detection circuit 3 in real time via resistor R4, and dynamically analyzes the reactive power demand of the load in conjunction with the stable power supply VD provided by the soft-start power supply circuit 1. When an inductive load is detected causing a voltage drop or a decrease in the power factor, U2 sends a control signal to the base of transistor KT3 (adjusting the drive current via a network of resistors R1 and R5), causing KT3 to conduct and activating the coil of relay KT2. Its contacts close, connecting the compensation capacitor bank (through an RC buffer network composed of capacitors C1 and C2 and resistors R6 and R9) to the power grid. The capacitive reactive current of the capacitors cancels the inductive reactive component of the load. At the same time, the charging and discharging circuit composed of resistors R7 and R8 and capacitors C1 and C2 suppresses the surge current at the moment of switching, preventing voltage overshoot. As the load changes, the microprocessor U2 controls the switching frequency of relay switch KT2 through a cyclic detection-decision-execution mechanism, using the dynamic connection / disconnection of capacitors to balance the reactive power of the system, ultimately achieving voltage stability and power factor improvement.

[0042] In one embodiment, the voltage detection circuit 3 includes resistors R11, R12, R13, R14, R15 and operational amplifier IC1.

[0043] In this circuit, the first pin of operational amplifier IC1 is connected to one end of resistor R11 and one end of resistor R14, and the other end of resistor R14 is grounded. The second pin of operational amplifier IC1 is connected to one end of resistor R13, the third pin of operational amplifier IC1, and the other end of resistor R9. The fourth pin of operational amplifier IC1 is connected to the VCC terminal, and the fifth pin of operational amplifier IC1 is grounded. The other end of resistor R11 is connected to one end of resistor R12 and to the POWER terminal. The other end of resistor R12 is connected to the other end of resistor R13 and one end of resistor R15, and the other end of resistor R15 is grounded. Resistor R15 is the load resistor in voltage detection circuit 3.

[0044] Specifically, the working principle of voltage detection circuit 3 is as follows:

[0045] The POWER signal is attenuated to a safe range by a voltage divider network consisting of resistors R11 and R12. The divided signal is then input to the non-inverting input (pin 3) of operational amplifier IC1 via resistor R13. Simultaneously, the inverting input (pin 2) of operational amplifier IC1 is grounded via resistor R15 to form a reference. Operational amplifier IC1 operates as a voltage follower or differential amplifier in single-supply mode. After impedance isolation or linear amplification, the divided signal is output from pin 1. Resistor R14 at the output terminal is used to limit current and suppress high-frequency interference. Finally, the conditioned voltage signal is transmitted to the microcontroller U2 of the low-voltage reactive power compensation circuit 2 via resistor R9, realizing real-time monitoring and closed-loop feedback control of grid voltage fluctuations.

[0046] To facilitate understanding of the above-mentioned technical solutions of this utility model, the working principle or operation method of this utility model in actual process will be described in detail below.

[0047] In practical applications, after AC power is input, the soft-start power supply circuit 1 converts AC to pulsating DC through a bridge rectifier with diodes D1-D4. The driver chip U1 controls the duty cycle of transistor KT1, gradually increasing the conduction rate of the primary coil of transformer T1. This results in a gradually rising DC output after full-wave rectification by diodes D5-D6 and LC filtering, suppressing the initial surge current. The voltage detection circuit 3 samples the grid voltage through a voltage divider between resistors R11 and R12, and after conditioning by operational amplifier IC1, feeds it back to the low-voltage reactive power compensation circuit in real time. The microcontroller U2 of the compensation circuit 2 combines voltage fluctuation data with a preset power factor target to dynamically calculate the required compensation capacity and control transistor KT3 to drive relay KT2 to switch capacitor banks. The capacitive reactive current injected through the series capacitor offsets the inductive reactive component of the load. At the same time, the buffer network composed of resistor R7-resistor R9 and capacitor C1-capacitor C2 absorbs the transient overvoltage during switching, thus forming a cyclic control of "voltage sampling → decision compensation → capacitor adjustment → closed-loop feedback", ultimately achieving grid voltage stability, power factor improvement and line loss reduction.

[0048] In summary, by utilizing the above-mentioned technical solutions of this utility model, the soft-start power supply circuit enables smooth startup and stable power supply, effectively suppressing the inrush current during startup, preventing grid voltage fluctuations, improving system safety and reliability, ensuring long-term stable operation of the compensation device, extending equipment lifespan, and reducing interference to the grid and other electrical equipment. By setting up a low-voltage reactive power compensation circuit, this utility model can monitor and automatically adjust the reactive power compensation amount in real time, accurately compensate for the reactive power of inductive loads, optimize the power factor, reduce reactive power losses in the grid, and improve power quality. Simultaneously, through the control of relays and transistors, efficient switching and stable operation of the circuit are ensured, guaranteeing equipment safety and long lifespan. Furthermore, through the precise detection of the resistor voltage divider network and operational amplifier IC1, this utility model achieves real-time monitoring and signal conditioning of the grid voltage, ensuring that the compensation system can accurately acquire voltage change information, providing reliable data support for reactive power compensation control, thereby avoiding over-compensation or under-compensation, effectively protecting equipment from voltage fluctuations, and extending system lifespan.

[0049] In this utility model, unless otherwise explicitly specified and limited, the terms "installation", "setting", "connection", "fixing", "screw connection", 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 or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection 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 utility model according to the specific circumstances.

[0050] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A low-voltage series reactive power compensation device, characterized in that, The low-voltage series reactive power compensation device includes: A soft-start power supply circuit (1) is used to control the slow rise of the starting current and suppress surge impact; (2) Low-voltage reactive power compensation circuit for dynamically adjusting the capacitive reactive power output of series capacitors and compensating for the reactive power deficit of inductive loads. A voltage detection circuit (3) is used to track circuit voltage fluctuations in real time and generate voltage feedback signals required for compensation control. The output terminal of the soft-start power supply circuit (1) is electrically connected to the input terminal of the low-voltage reactive power compensation circuit (2), and the output terminal of the low-voltage reactive power compensation circuit (2) is electrically connected to the input terminal of the voltage detection circuit (3).

2. The low-voltage series reactive power compensation device according to claim 1, characterized in that, The soft-start power supply circuit (1) includes diodes D1, D2, D3, D4, D5, and D6, transformer T1, capacitors C3 and C4, inductor L1, transistor KT1, and driver chip U1. In this configuration, the cathode of diode D1 is connected to the cathode of diode D3 and one end of resistor R10. The anode of diode D1 is connected to the cathode of diode D2 and connected to the AC terminal. The anode of diode D2 is connected to the anode of diode D4, the second pin of driver chip U2, one end of capacitor C3, and the emitter of transistor KT1. The cathode of diode D4 is connected to the anode of diode D3 and connected to the AC terminal. The first pin of driver chip U1 is connected to the base of transistor KT1. The collector is connected to the third pin of the transformer T1. The first pin of the transformer T1 is connected to the other end of the capacitor C3 and the other end of the resistor R10. The second pin of the transformer T1 is connected to the positive terminal of the diode D5. The negative terminal of the diode D5 is connected to one end of the inductor L1 and the negative terminal of the diode D6. The other end of the inductor L1 is connected to one end of the capacitor C4. The other end of the capacitor C4 is connected to the positive terminal of the diode D6, the fourth pin of the transformer T1, and the low-voltage reactive power compensation circuit (2).

3. A low-voltage series reactive power compensation device according to claim 2, characterized in that, Both capacitor C3 and capacitor C4 are energy storage capacitors.

4. A low-voltage series reactive power compensation device according to claim 2, characterized in that, The low-voltage reactive power compensation circuit (2) includes resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, transistor KT3, relay switch KT2, and microcontroller U2. In this configuration, one end of resistor R1 is connected to one end of resistor R5 and one end of capacitor C2. The other end of capacitor C2 is connected to the base of transistor KT1. The collector of transistor KT1 is connected to one end of resistor R2 and one end of capacitor C1. The other end of capacitor C1 is connected to the first pin of relay switch KT2. The second pin of relay switch KT2 is connected to one end of resistor R7. The other end of resistor R7 is connected to one end of resistor R6 and one end of resistor R1. The other end is connected to the soft-start power supply circuit (1), the other end of the resistor R6 is connected to the emitter of the transistor KT1, the third pin of the relay switch KT2 is connected to one end of the resistor R3, the other end of the resistor R3 is connected to one end of the resistor R8, one end of the resistor R4 and one end of the resistor R9 respectively, the other end of the resistor R8 is connected to the other end of the resistor R5, the other end of the resistor R9 is connected to the voltage detection circuit (3), and the other end of the resistor R4 is connected to the microcontroller U2.

5. A low-voltage series reactive power compensation device according to claim 4, characterized in that, The voltage detection circuit (3) includes resistors R11, R12, R13, R14, R15 and operational amplifier IC1; Specifically, the first pin of the operational amplifier IC1 is connected to one end of resistor R11 and one end of resistor R14, with the other end of resistor R14 grounded. The second pin of the operational amplifier IC1 is connected to one end of resistor R13, the third pin of the operational amplifier IC1, and the other end of resistor R9. The fourth pin of the operational amplifier IC1 is connected to the VCC terminal. The fifth pin of the operational amplifier IC1 is grounded. The other end of resistor R11 is connected to one end of resistor R12 and to the POWER terminal. The other end of resistor R12 is connected to the other end of resistor R13 and one end of resistor R15, with the other end of resistor R15 grounded.

6. A low-voltage series reactive power compensation device according to claim 5, characterized in that, The resistor R15 is the load resistor in the voltage detection circuit (3).

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