Modularized low-voltage electric energy quality compensation circuit and device thereof

Abstract

The utility model discloses a modularized low-voltage electric energy quality compensation circuit and a device thereof, and the circuit comprises a power input unit which is configured to input an AC power supply, and is internally provided with a rectifier bridge; a rectifying unit configured to convert the alternating current power supply into direct current; the filtering unit is configured to perform filtering shaping on the direct current; the signal detection unit is configured to monitor voltage or current signals in the circuit, an analog switch is arranged in the signal detection unit, and the analog switch is used for controlling connection or disconnection of the signal detection unit; according to the utility model, through the modularized and integrated design, the circuit structure is simplified, the requirement of external components is reduced, the cost is reduced, the efficiency and performance of the circuit are improved, harmonic waves can be effectively inhibited, the power factor is improved, the electric energy quality is improved, and the stability and safety of the compensation circuit are enhanced; and the method is suitable for various industrial application scenes.

Description

TECHNICAL FIELD

[0001] The utility model relates to a modular low-voltage power quality compensation circuit and device, belonging to the technical field of power supply or distribution circuit device. BACKGROUND

[0002] With the development of power electronics technology and the improvement of industrial automation level, the requirement for power quality is also higher and higher. In low-voltage distribution system, power quality problems mainly include voltage fluctuation, harmonic pollution, three-phase imbalance and low power factor, etc. The above problems not only affect the stability and reliability of the power system, but also may cause equipment damage, energy efficiency reduction and production interruption. Therefore, it is particularly important to effectively compensate and control low-voltage power quality. The existing low-voltage power quality compensation device includes reactive power compensation device, active filter and passive filter, etc. The above device can improve power quality to a certain extent, but still has the following shortcomings:

[0003] Single function: most of the existing devices can only compensate for specific power quality problems, such as reactive power compensation device can only be used to adjust power factor, and active filter can only be used to filter out harmonics, lacking coordination ability.

[0004] Insufficient dynamic response: harmonic suppression reactive power compensation device based on fixed capacitance / reactance cannot cope with rapidly changing load conditions and power grid environment.

[0005] Lack of flexibility: the compensation effect and adaptability of the existing device are limited when facing different load conditions and power grid environment, and it is difficult to realize dynamic optimization.

[0006] Control strategy conflict: the multi-compensation target cooperative control algorithm is imperfect, and there is parameter coupling interference between harmonic control and reactive power compensation adjustment, affecting the comprehensive control precision.

[0007] Low system integration: the existing device is usually composed of multiple independent components, lacking modular design, resulting in low system integration, complex installation and maintenance.

[0008] In summary, the existing technology cannot meet people's requirements and needs to be improved. UTILITY MODEL CONTENT

[0009] The utility model aims at providing a modular low-voltage power quality compensation circuit and device, solving the defects in the prior art.

[0010] The utility model provides the following scheme:

[0011] According to one aspect of the utility model, a kind of modular low voltage power quality compensation circuit is provided, comprising: power input unit, configured to input alternating current power, the rectifier bridge is provided in the power input unit;Rectifying unit, configured to convert the alternating current power into direct current;Filter unit, configured to filter and shape the direct current;Signal detection unit, configured to monitor voltage or current signal in circuit, analog switch is provided in the signal detection unit, and the analog switch is used to control the connection or disconnection of signal detection unit;The modular low voltage power quality compensation circuit is connected and disconnected by analog switch in signal detection unit, for the state of the modular low voltage power quality compensation circuit is monitored in real time.

[0012] According to at least one specific embodiment of the utility model, the power input unit is provided with alternating current source, one end of the alternating current source is connected with the rectifying unit, the other end is connected with the load of modular low voltage power quality compensation circuit, and the two ends of the load are respectively connected with first relay switch and second relay switch.

[0013] According to at least one specific embodiment of the utility model, one end of the first relay switch is connected between the alternating current source and the load, and the other end is connected with the filter unit, one end of the second relay switch is connected between the load and the signal detection unit, and the other end is connected with the filter unit.

[0014] According to at least one specific embodiment of the utility model, the rectifying unit includes first inductor, first capacitor, first diode and second diode, one end of the first inductor is connected with the alternating current source in the power input unit, and the other end is connected with the first diode, the second diode is connected across the two ends of the first diode, one end of the first capacitor is connected with the first and second diodes, and the other end is grounded.

[0015] According to at least one specific embodiment of the utility model, the filter unit includes first resistor, second inductor, third inductor, second capacitor and first mutual inductor, one end of the second inductor is connected with the first relay, and the other end is connected with one end of the third inductor, the other end of the third inductor is connected with the first resistor, the other end of the first resistor is connected with the first reactor, the other end of the first reactor is grounded, and the second capacitor is connected across the third inductor and the first resistor.

[0016] According to at least one embodiment of the present application, the signal detection unit comprises a first transistor, a second transistor and an analog switch, the base of the first transistor is connected with the collector of the second transistor, the collector of the first transistor is connected with one end of a third resistor, the other end of the third resistor is connected with a power supply, the base of the second transistor is connected with a digital channel control pin of the analog switch, and the emitter of the second transistor is grounded.

[0017] According to at least one embodiment of the present application, the signal detection unit comprises a first transistor, a second transistor and an analog switch, the base of the first transistor is connected with the collector of the second transistor, the collector of the first transistor is connected with one end of a third resistor, the other end of the third resistor is connected with a power supply, the base of the second transistor is connected with a digital channel control pin of the analog switch, and the emitter of the second transistor is grounded.

[0018] According to at least one embodiment of the present application, the switch pin of the analog switch is connected across the third reactor of the filter unit, and the signal channel pin, the enable pin and the digital channel control pin of the analog switch are connected with the base of the second transistor.

[0019] According to at least one embodiment of the present application, the signal detection unit further comprises a fourth resistor and a second mutual inductor, one end of the fourth resistor is connected with a power supply, the other end is connected between the base of the first transistor and the collector of the second transistor, one end of the second mutual inductor is connected with a load, and the other end is a signal detection end.

[0020] According to another aspect of the present application, a modular low-voltage power quality compensation device is provided, wherein the modular low-voltage power quality compensation circuit is included in the modular low-voltage power quality compensation device.

[0021] Compared with the prior art, the present application has the following advantages:

[0022] The modular low-voltage power quality compensation circuit and the device thereof can improve the power quality, integrate the power input unit, the rectifier unit, the filter unit and the signal detection unit through the modular structure, can monitor and dynamically respond to the change of the circuit state in real time, and ensure the stability and reliability of the power quality.

[0023] The utility model discloses based on modularization design, makes compensation circuit easy to install, maintain and upgrade, and each functional unit can independently operate or work cooperatively, and through the analog switch of configuration signal detection unit, can control the connection and disconnection of signal, realizes the real -time monitoring of circuit state, the quick response of electric energy quality's change, adjusts in time, can dynamically according to the voltage or current signal of monitoring, adjusts its working condition to adapt to different load condition and power grid environment, thereby improves electric energy quality, through setting relay switch between power input unit and load provides additional protection measure, prevents circuit overload or short circuit, strengthens the security and reliability of compensation circuit.

[0024] The modular low-voltage power quality compensation circuit and the device thereof simplify the circuit structure through modularization and integration, reduce the demand for external components, reduce the cost, improve the efficiency and performance of the circuit, effectively suppress harmonics, compensate for reactive power through the rectifier unit, improve the power factor, improve the power quality, and enhance the stability and safety of the compensation circuit, and can be applied to various industrial application scenarios. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the specific embodiments of the utility model or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings described below are some embodiments of the utility model, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0026] Figure 1 It is the principle diagram of modular low-voltage power quality compensation circuit.

[0027] Figure 2 It is the circuit principle diagram of modular low-voltage power quality compensation circuit. DETAILED DESCRIPTION

[0028] The technical solutions of the utility model will be described clearly and completely in combination with the drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the utility model.

[0029] As shown in Figure 1 The modular low-voltage power quality compensation circuit and the device thereof include power input unit A, rectifier unit B, filter unit C, signal detection unit D, wherein:

[0030] The power input unit A is configured to input an alternating power supply, and a rectifier bridge is arranged in the power input unit A.

[0031] The rectification unit B is configured to convert the alternating power supply into direct current.

[0032] The filter unit C is configured to filter and shape the direct current.

[0033] The signal detection unit D is configured to monitor the voltage or current signal in the circuit, and an analog switch is arranged in the signal detection unit D to control the connection and disconnection of the signal detection unit.

[0034] The modular low-voltage power quality compensation circuit controls the connection and disconnection of the signal detection unit through the analog switch in the signal detection unit, for real-time monitoring of the state of the modular low-voltage power quality compensation circuit.

[0035] In Figure 1 In the modular low-voltage power quality compensation circuit shown in the figure, the power input unit A provides basic power for the circuit, receives and introduces external alternating power supply, so that the modular low-voltage power quality compensation circuit can obtain the required power from the low-voltage power grid, and provides the basis for subsequent power conversion and processing. The rectification unit B converts the input alternating current into direct current through the rectifier bridge, provides stable direct current power for the circuit, so that the compensation circuit can process and utilize direct current power. The filter unit C filters and shapes the rectified direct current to eliminate possible voltage fluctuations and ripples, which is used to improve the stability and quality of the power, ensure the output of the direct current is flat and suitable for sensitive equipment, thereby reducing the risk of damage to the equipment. The signal detection unit D is responsible for monitoring the voltage or current signal in the circuit, and controls its connection and disconnection through the analog switch. The signal detection unit D enables the circuit to respond to changes in power quality in real time, and through the control of the analog switch, it realizes accurate monitoring and adjustment of the state of the circuit, thereby improving the adaptability and reliability of the entire compensation circuit.

[0036] In summary, the power input unit A, the rectification unit B, the filter unit C and the signal detection unit D work together to realize efficient conversion, stable output and real-time monitoring of power, effectively improve the power quality of the low-voltage power grid, and enhance the stability and reliability of the power grid.

[0037] As Figure 2As shown, an alternating current source AC is provided in the power input unit A, one end of the alternating current source AC is connected with the rectifier unit B, the other end is connected with the load of the modular low-voltage power quality compensation circuit, and the two ends of the load are respectively connected with the first relay switch K1 and the second relay switch K2, wherein one end of the first relay switch K1 is connected between the alternating current source AC and the load, and the other end is connected with the filter unit C, one end of the second relay switch K2 is connected between the load and the signal detection unit D, and the other end is connected with the filter unit C. The power input unit A and its alternating current source AC are one of the core components of the compensation circuit. In order to enhance the control ability and safety of the circuit, the two ends of the load are respectively controlled by the first relay switch K1 and the second relay switch K2. By setting the first relay switch K1 and the second relay switch K2 at both ends of the load, the power connection of the load can be independently controlled to achieve more precise circuit management. For example, the first and second relay switches K1 and K2 in the power input unit A can be independently controlled, the power supply state of the rectifier unit B can be synchronously controlled or fault isolation can be performed without affecting other circuit parts.

[0038] The rectifier unit B includes a first inductor L1, a first capacitor C1, a first diode D1 and a second diode D2. One end of the first inductor L1 is connected with the alternating current source AC in the power input unit A, and the other end is connected with the first diode D1. The second diode D2 is connected across the first diode D1. One end of the first capacitor C1 is connected with the first and second diodes D1 and D2, and the other end is grounded.

[0039] In the rectifier unit B, the circuit design adopts a full-wave rectification configuration. The first inductor L1 is used to limit the rising rate of current, reduce current impact, and provide electromagnetic interference suppression function. The first and second diodes D1 and D2 are connected in a bridge structure to ensure that a single direction of DC output is generated regardless of the phase change of the alternating current, allowing both positive and negative half cycles of the alternating current to be utilized, thereby improving the rectification efficiency. The first capacitor C1 is connected between the connection point of the first and second diodes D1 and D2 and the ground, and is used to smooth the rectified pulsating DC current, reduce ripple voltage, and provide more stable DC output. The rectifier unit B realizes full-wave rectification through the diode configuration of the bridge structure, improves the efficiency of the conversion of alternating current energy to direct current energy, controls the rapid change of current through the first inductor L1, reduces electromagnetic interference in the circuit, protects subsequent circuit elements from damage, and utilizes the filtering effect of the first capacitor C1 to help eliminate voltage fluctuations after rectification, thereby providing higher quality DC power to subsequent circuits. In summary, through the cooperation of inductors and capacitors, the rectifier unit B can provide more stable and smoother DC output, which is conducive to improving the performance and reliability of the entire modular low-voltage power quality compensation circuit.

[0040] In the filter unit C, including the first resistor R1, the second inductor L2, the third inductor L3, the second capacitor C2, the first mutual inductor CT1, the first reactor LD1, the second reactor LD2, the third reactor LD3, the second inductor L2 is connected with the first relay switch K1 at one end, and the other end is connected with one end of the third inductor L3, the other end of the third inductor L3 is connected with the first resistor R1, the other end of the first resistor R1 is connected with the first reactor LD1, the other end of the first reactor LD1 is grounded, the second capacitor C2 is connected between the third inductor L3 and the first resistor R1, one end of the first reactor LD1 is connected with the second relay switch K2, the other end of the first reactor LD1 is connected with one end of the second reactor LD2, the other end of the second reactor LD2 is connected with one end of the third reactor LD3, the other end of the third reactor LD3 is connected with one end of the second resistor R2, the other end of the second resistor R2 is grounded.

[0041] The reactor in the filter unit C is used to filter the current size and phase in the filter unit C, and the circuit characteristics can be changed by introducing inductive or capacitive impedance, which can limit short-circuit current, improve power factor, filter and stabilize voltage, etc. The reactor can limit the change of current, which helps to reduce electromagnetic interference (EMI) in the circuit and improve power quality. Multiple reactors in the filter unit C can be used to form a harmonic filter, which works with the second capacitor C2 to absorb or suppress harmonics of a certain frequency, improving power quality. The first, second and third reactors LD1, LD2 and LD3 are used to filter out harmonics in the filter unit C, improve power quality, stabilize voltage and current in the filter unit C, and ensure stable operation of the circuit.

[0042] The filter unit C is formed by connecting inductors, mutual inductors, resistors and other circuit elements to form a filter network, which is used to further filter and shape the rectified DC voltage. Through the series connection of the second inductor L2 and the third inductor L3, and the cooperation of the first resistor R1 and the second capacitor C2, the filter unit C can effectively smooth the current waveform after rectification, reduce the high-frequency components in the current, and thus provide a more stable DC power supply. The first mutual inductor CT1 is used to monitor and stabilize the voltage to ensure that the load obtains a constant voltage supply, which is used to ensure that sensitive electronic components can obtain a constant and effective voltage supply. The series structure of the first reactor LD1, the second reactor LD2 and the third reactor LD3 helps to suppress harmonics in the circuit, reduce electromagnetic interference and improve power quality. The setting of the first relay switch K1 and the second relay switch K2 allows the input and output of the filter unit C to be controlled, providing additional safety and flexibility, which can disconnect or connect the circuit as needed. The ground connection of the first reactor LD1 and the second resistor R2 provides a low-impedance path for the circuit, which helps to protect the circuit from voltage spikes and transients.

[0043] In summary, the filter unit C improves the electromagnetic compatibility of the entire compensation circuit, reduces interference to other electronic devices, realizes effective filtering and shaping of the rectified direct current, thereby improving power quality, enhancing the stability and reliability of the circuit, and providing a high-quality direct current power supply for other parts of the modular low-voltage power quality compensation circuit.

[0044] The signal detection unit D includes a first transistor Q1, a second transistor Q2, a fourth resistor R4, and a second transformer CT2, an analog switch U1, a signal detection end signal detecting, the base of the first transistor Q1 is connected with the collector of the second transistor Q2, the collector of the first transistor Q1 is connected with one end of the third resistor R3, the other end of the third resistor R3 is connected with the power supply VCC, the base of the second transistor Q2 is connected with the digital channel control pin D0 of the analog switch U1, and the emitter of the second transistor Q2 is grounded. The switch pins S1-S4 of the analog switch U1 are connected across the two ends of the third reactor LD3 of the filter unit C, and the signal channel pins C1-C4, the enable pin ENB and the digital channel control pin D0 of the analog switch are connected with the base of the second transistor Q2. One end of the fourth resistor R4 is connected with the power supply VCC, and the other end of the fourth resistor R4 is connected between the base of the first transistor Q1 and the collector of the second transistor Q2. One end of the second transformer CT2 is connected with the load, and the other end is the signal detection end signal detecting. The signal detection end signal detecting monitors and analyzes the voltage or current signal in the circuit, and is used for real-time monitoring and adjustment of the working state of the circuit, realizes accurate control and monitoring of the circuit state. The signal detection end signal detecting can monitor the voltage or current signal in the circuit in real time, provide instant feedback information for the circuit, and real-time monitoring can ensure that the circuit responds quickly to grid changes. The signals collected by the signal detection end signal detecting can be used for further processing, such as controlling the transmission path of the signal through the analog switch U1 to realize accurate control of the signal, so that the circuit can adapt to different working conditions and requirements. The signal detection end signal detecting can also cooperate with the protection circuit to trigger the protection mechanism through the analog switch U1 when detecting abnormal signals such as overvoltage or overcurrent, disconnect the circuit or adjust the working state to avoid damage, optimize power quality, adapt to different load demands, thereby improving power utilization efficiency and circuit stability.

[0045] The analog switch U1 has the advantages of low power consumption, high speed, no mechanical contact, small size, long service life and the like. The analog switch U1 can realize signal routing control, signal channel management, dynamic response and electrical isolation and the like in the application. For example, the analog switch U1 is used for controlling the routing of signals in the signal detection unit D, or the analog switch U1 can be connected across the third reactor LD3 of the filter unit C through the switch pins S1-S4, so as to control the flow direction of the signals. The signal channel pins C1-C4, the enable pin ENB and the digital channel control pin DO of the analog switch U1 are connected with the base of the second transistor Q2, so as to allow the analog switch U1 to turn on or off the signal channel according to the digital control signal. The analog switch U1 provides electrical isolation for the circuits on both sides, protects the sensitive measurement and control circuit from high voltage or current damage, and enhances the safety of the compensation circuit. Through the above circuit connection structure, the analog switch U1 can quickly respond to the control signal, realize real-time monitoring and dynamic adjustment of the circuit state, and thus improve the performance and reliability of the entire modular low-voltage power quality compensation circuit.

[0046] The transformer in the signal detection unit D is used for monitoring the current and voltage, and cooperates with the capacitor in the filter unit C to form a filter network, suppresses harmonics, smooths the current and voltage waveform, and improves the power quality. The signal detection unit D is responsible for monitoring the voltage or current signal in the circuit. In the signal detection unit D, the second transformer CT2 can accurately monitor the load current to provide a real-time current signal for the circuit. The analog switch U1 can control the signal detection unit D to flexibly control the transmission path of the signal, allowing selective monitoring of different circuit parameters. The cascade structure of the first transistor Q1 and the second transistor Q2 can be used for signal amplification to enhance the strength of the detection signal for subsequent processing. The fourth resistor R4 provides current limiting to protect the first and second transistors Q1 and Q2 from excessive current damage. The analog switch U1 provides electrical isolation to ensure a safe distance between the signal detection unit D and the main circuit, preventing the influence of high voltage or current on the detection circuit. Through the fast switching capability of the analog switch U1, the signal detection unit D can quickly respond to changes in the circuit state to achieve dynamic monitoring.

[0047] In summary, the design of the signal detection unit D improves the monitoring capability and overall performance of the modular low-voltage power quality compensation circuit through accurate monitoring, flexible control, signal amplification, protection mechanism, electrical isolation and dynamic response, ensuring the stability and reliability of the circuit.

[0048] As the alternative technical scheme of the utility model, one or more voltage regulators can be added in the power input unit A to ensure that the alternating voltage received by the rectifier unit B is within the preset range, or one or more overvoltage protection circuits can be added in the power input unit A, when detecting abnormal voltage rise, the signal is sent through the analog switch U1 in the signal detection unit D, the power supply of the rectifier unit B is cut off, and other circuit modules in the modular low-voltage power quality compensation circuit are protected. A current feedback loop can be arranged between the rectifier unit B and the filter unit C, the current is monitored through the second mutual inductor CT2, and the signal is fed back to the rectifier unit B, so that the rectifier parameters are dynamically adjusted, and the power quality is optimized.

[0049] In order to further realize the cooperative relationship between the rectifier unit B and the filter unit C, the output end of the rectifier unit B can be connected to the second inductor L2 in the filter unit C, a new connection relationship is formed, the new connection relationship can reduce the current ripple after rectification, improve the smoothness of direct current, and: a current feedback loop is arranged between the rectifier unit B and the filter unit C, the current is monitored through the second mutual inductor CT2, and the signal is fed back to the rectifier unit B, so that the rectifier parameters are dynamically adjusted, and the power quality is optimized.

[0050] In order to further improve the cooperative relationship between the filter unit C and the signal detection unit D, and enhance the control of the signal detection unit D on other units, through the cooperative work of the third inductor L3 in the filter unit C and the second mutual inductor CT2 of the signal detection unit D, the filtered current quality is monitored, and the information is transmitted to the signal detection unit D for analysis, the second capacitor C2 in the filter unit C can work cooperatively with the analog switch U1 in the signal detection unit D, for example, the signal channel pin C1-C4 connected to the analog switch U1, the charging and discharging of the capacitor is controlled through the analog switch U1, and the dynamic adjustment of the filtering effect is realized. For the analog switch U1 in the signal detection unit D, the control signal can be sent through the digital channel control pin D0 to adjust the voltage regulator in the power input unit A, so that the input voltage is finely controlled, when the signal detection unit D detects abnormal signal, the first relay switch K1 and the second relay switch K2 are triggered through the analog switch U1, the power connection of the rectifier unit B and the filter unit C is cut off or adjusted, and the circuit is protected from damage.

[0051] Exemplarily, a central control unit can also be arranged in the modular low-voltage power quality compensation circuit, the central control unit is connected with the signal detection unit D, according to the detected power quality data, the power input unit A, the rectification unit B and the filter unit C are comprehensively controlled through the analog switch U1 and the first and second relay switches K1 and K2, the parameters of the filter unit C can be adjusted through the signal detection unit D according to the change of the load, so as to adapt to different load requirements, improve the power quality, and improve the performance and reliability of the entire modular low-voltage power quality compensation circuit.

[0052] Those skilled in the art will appreciate that unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0053] It should be noted that the specification and claims of the present application use certain terms to describe particular elements of the application. Those skilled in the art will recognize that elements defined by these terms can vary in structure, appearance, and function depending on the context in which the term is used. As used herein, the singular form "a", "an", and "the" include plural references unless the context clearly dictates otherwise.

[0054] The technical features of the above embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not contradict, they should be considered within the scope of the present application.

[0055] In the description of the specification of the present application, the description of the reference terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0056] In addition, the technical solutions of each embodiment of the present application can be combined with each other, but it must be based on the realization of ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, also not within the protection scope required by the present application.

[0057] It should be finally pointed out that: the above embodiments are only used to illustrate the technical solutions of the present application, but not limit them. Although the embodiments of the present application are described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some or all of the technical features can be replaced equivalently, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the embodiments of the present application.

Claims

1. A modular low voltage power quality compensation circuit, characterized by, include: A power input unit is configured to input AC power, and a rectifier bridge is provided in the power input unit; A rectifier unit is configured to convert the AC power supply into DC power. The filtering unit is configured to filter and shape the DC current. A signal detection unit is configured to monitor voltage or current signals in a circuit. An analog switch is provided in the signal detection unit to control the connection or disconnection of the signal detection unit. The modular low-voltage power quality compensation circuit controls the connection and disconnection of the signal detection unit through an analog switch in the signal detection unit, which is used to monitor the status of the modular low-voltage power quality compensation circuit in real time.

2. The modular low voltage power quality compensation circuit of claim 1, wherein, The power input unit is equipped with an AC current source. One end of the AC current source is connected to the rectifier unit, and the other end is connected to the load of the modular low-voltage power quality compensation circuit. The two ends of the load are respectively connected to a first relay switch and a second relay switch.

3. The modular low voltage power quality compensation circuit of claim 2, wherein, One end of the first relay switch is connected between the AC current source and the load, and the other end is connected to the filter unit. One end of the second relay switch is connected between the load and the signal detection unit, and the other end is connected to the filter unit.

4. The modular low voltage power quality compensation circuit of claim 1, wherein, The rectifier unit includes a first inductor, a first capacitor, a first diode, and a second diode. One end of the first inductor is connected to the AC current source in the power input unit, and the other end is connected to the first diode. The second diode is connected across the two ends of the first diode. One end of the first capacitor is connected to the first and second diodes, and the other end is grounded.

5. The modular low voltage power quality compensation circuit of claim 1, wherein, The filtering unit includes a first resistor, a second inductor, a third inductor, a second capacitor, and a first transformer. One end of the second inductor is connected to a first relay, and the other end is connected to one end of the third inductor. The other end of the third inductor is connected to the first resistor, and the other end of the first resistor is connected to a first reactor. The other end of the first reactor is grounded, and the second capacitor is connected between the third inductor and the first resistor.

6. The modular low voltage power quality compensation circuit of claim 5, wherein, It also includes a first reactor, a second reactor, and a third reactor. One end of the first reactor is connected to a second relay, the other end of the first reactor is connected to one end of the second reactor, the other end of the second reactor is connected to one end of the third reactor, the other end of the third reactor is connected to one end of a second resistor, and the other end of the second resistor is grounded.

7. The modular low voltage power quality compensation circuit of claim 1, wherein, The signal detection unit includes a first transistor, a second transistor, and an analog switch. The base of the first transistor is connected to the collector of the second transistor. The collector of the first transistor is connected to one end of a third resistor, and the other end of the third resistor is connected to a power supply. The base of the second transistor is connected to the digital channel control pin of the analog switch, and the emitter of the second transistor is grounded.

8. The modular low voltage power quality compensation circuit of claim 7, wherein, The switching pins of the analog switch are connected across the two ends of the third reactor of the filter unit, and the signal channel pins, enable pins, and digital channel control management pins of the analog switch are connected to the base of the second transistor.

9. The modular low voltage power quality compensation circuit of claim 7, wherein, The signal detection unit further comprises a fourth resistor and a second mutual inductor, one end of the fourth resistor is connected with the power supply, the other end is connected between the base of the first transistor and the collector of the second transistor, one end of the second mutual inductor is connected with the load, and the other end is a signal detection end.

10. A modular low voltage power quality compensation device, characterized by, The modular low-voltage power quality compensation device comprises the modular low-voltage power quality compensation circuit according to any one of claims 1 to 9.

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