Electric energy filter with abnormal voltage compensation function

Abstract

The utility model discloses an electric energy filter with a voltage abnormity compensation function, which can monitor voltage abnormity fluctuation conditions such as voltage sag, voltage swell, voltage interruption and the like of each phase voltage by respectively arranging input sampling voltage transformers on three input phase lines of commercial power. A voltage compensation module is arranged in front of an input winding of an isolation transformer, the voltage compensation module can output compensation voltage with the same frequency, phase locking and adjustable amplitude, and a controller can control the compensation voltage of the voltage compensation module according to a three-phase voltage monitoring result, so that the compensation voltage and three-phase input voltage of commercial power are superposed or counteracted. Therefore, the input voltage and the output voltage of the isolation transformer are kept stable, the voltage abnormity automatic compensation function is realized, and a power supply with stable voltage is provided for a load.

Description

Technical Field

[0001] The utility model relates to the technical field of power filters, and in particular to a power filter with a voltage anomaly compensation function. Background Art

[0002] At present, with the rapid popularization of power filters, the diversity and complexity of the application environment are also constantly expanding during the application process. For example, in a power distribution and transmission system, instantaneous disturbances of the grid voltage or short-circuit faults of the load will cause problems such as voltage dips and rises in the branch voltages of sensitive loads. In various precision devices sensitive to power supply quality such as airport static inverters, it is required that the voltage sag range cannot have fluctuations at the 10mS level, and the losses caused by voltage mutations and other problems are countless every year. Therefore, it is of great practical significance to develop a power filter that can effectively solve the voltage fluctuation problem. Content of the Utility Model

[0003] The utility model provides a power filter with a voltage anomaly compensation function, which can realize the automatic voltage anomaly compensation function and provide a stable voltage power supply for the load.

[0004] According to one aspect of the utility model, there is provided a power filter with a voltage anomaly compensation function, including an input sampling voltage transformer, a contactor, a voltage compensation module, an isolation transformer and a controller. The input sampling voltage transformer is respectively arranged on three input phase lines of the commercial power for monitoring the three-phase input voltage of the commercial power. The contactor is respectively arranged on three input phase lines of the commercial power for controlling the on-off of the commercial power supply line. The input winding and the output winding of the isolation transformer are respectively connected to the contactor and the load for filtering the alternating current of the commercial power. The voltage compensation module is arranged between the contactor and the input winding of the isolation transformer for compensating the three-phase input voltage of the commercial power. The input sampling voltage transformer, the contactor and the voltage compensation module are all electrically connected to the controller. The controller is used for controlling the contactor to close or open, and is also used for controlling the compensation voltage of the voltage compensation module according to the monitoring result of the input sampling voltage transformer, so as to keep the input voltage and the output voltage of the isolation transformer stable.

[0005] Further, the voltage compensation module includes a three-phase rectifier ZL1, a first DC capacitor C1, a second DC capacitor C2, three IGBT modules PM, and three compensation coils L2. The input end of the three-phase rectifier ZL1 is connected to three input phase lines of the mains power supply, and is used to convert alternating current into direct current. The first DC capacitor C1 and the second DC capacitor C2 are connected in series to form a DC energy storage module. The output end of the three-phase rectifier ZL1 is connected to the DC energy storage module. The three IGBT modules PM are connected to the DC energy storage module in parallel. The three compensation coils L2 are respectively arranged on the three input phase lines of the mains power supply. The first end of each compensation coil L2 is connected to the middle point of the series connection of the first DC capacitor C1 and the second DC capacitor C2, and the other end is respectively connected to the output ends of the three IGBT modules PM. The three IGBT modules PM are all electrically connected to the controller.

[0006] Further, the voltage compensation module further includes a first discharge resistor R4 and a second discharge resistor R5. The first end of the first discharge resistor R4 is connected to the positive terminal of the first DC capacitor C1, and the second end is connected to the negative terminal of the first DC capacitor C1. The first end of the second discharge resistor R5 is connected to the positive terminal of the second DC capacitor C2, and the second end is connected to the negative terminal of the second DC capacitor C2. The first discharge resistor R4 and the second discharge resistor R5 are used to provide discharge circuits for the first DC capacitor C1 and the second DC capacitor C2 respectively when the power filter stops working.

[0007] Further, the voltage compensation module further includes a fuse FU1 connected in series between the DC energy storage module and the IGBT module.

[0008] Further, the voltage compensation module further includes a Hall current detector CT1 connected in series between the DC energy storage module and the IGBT module.

[0009] Further, at least one IGBT module PM is provided with a first temperature sensor RT1, and the first temperature sensor RT1 is electrically connected to the controller.

[0010] Further, it further includes a dual-power switch arranged between the output winding of the isolation transformer and the load. The dual-power switch is respectively connected to the output winding of the isolation transformer and the mains power supply. The dual-power switch is electrically connected to the controller, and the controller is further used to control the switching action of the dual-power switch.

[0011] Further, an arc suppression resistor is connected in parallel at both ends of each contactor.

[0012] Further, a circuit breaker QF is arranged on the three input phase lines of the mains power supply and / or on the three output phase lines of the isolation transformer.

[0013] Further, a reactor L1 is also provided on the three input phase lines of the mains power supply.

[0014] The utility model has the following beneficial effects:

[0015] The power filter with voltage anomaly compensation function of the utility model can monitor voltage anomaly fluctuations such as voltage sag, voltage swell, and voltage interruption of each phase voltage by respectively arranging input sampling voltage transformers on the three input phase lines of the mains power supply. A voltage compensation module is arranged before the input winding of the isolation transformer. The voltage compensation module can output a compensation voltage with the same frequency, phase-locked, and adjustable amplitude. The controller can control the compensation voltage of the voltage compensation module according to the monitoring results of the three-phase voltage, so that the compensation voltage is superimposed or offset with the three-phase input voltage of the mains power supply, so as to keep the input voltage and output voltage of the isolation transformer stable, realizing the function of automatic voltage anomaly compensation, and providing a power supply with stable voltage for the load.

[0016] In addition to the purposes, features, and advantages described above, the utility model has other purposes, features, and advantages. The following will refer to the drawings to make a further detailed description of the utility model. Description of the Drawings

[0017] The drawings forming a part of this application are used to provide a further understanding of the utility model. The schematic embodiments of the utility model and their descriptions are used to explain the utility model and do not constitute an improper limitation of the utility model. In the drawings:

[0018] Figure 1 is a schematic circuit diagram of the power filter with voltage anomaly compensation function of the preferred embodiment of this application.

[0019] Description of the Reference Signs

[0020] 1. Input sampling voltage transformer; 2. Contactor; 3. Voltage compensation module; 4. Isolation transformer; 5. Dual power supply switch; 6. Output voltage transformer; 7. Leakage current transformer. Detailed Embodiments

[0021] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The following will refer to the drawings and combine with the embodiments to make a detailed description of this application.

[0022] Refer to Figure 1As shown in the figure, a preferred embodiment of the present application provides an electric energy filter with a voltage anomaly compensation function, which includes an input sampling voltage transformer 1, a contactor 2, a voltage compensation module 3, an isolation transformer 4, and a controller. The input sampling voltage transformer 1 is respectively arranged on three input phase lines of the mains power supply, and is used to monitor the three-phase input voltage of the mains power supply. The contactor 2 is respectively arranged on three input phase lines of the mains power supply, behind the input sampling voltage transformer 1, and is used to control the on / off of the mains power supply line. It can be understood that by respectively arranging the input sampling voltage transformer 1 on three input phase lines of the mains power supply to monitor the voltage of each phase of the mains power supply, voltage anomaly fluctuations such as voltage dips, voltage surges, and voltage interruptions of each phase voltage can be monitored. Also, by respectively arranging the contactor 2 on three input phase lines of the mains power supply, the input of three-phase voltage can be controlled, where the three-phase voltage is synchronously controlled, that is, the three input phase lines are simultaneously turned on or simultaneously turned off. The input winding and output winding of the isolation transformer 4 are respectively connected to the contactor 2 and the load, and are used to filter the alternating current of the mains power supply. Among them, the isolation transformer 4 can convert the alternating current of the mains power supply into safe alternating current, and the ground current of each phase after conversion is less than the human body safety current value. The specific filtering principle belongs to the prior art and will not be elaborated here. Reference can be made to the patent CN208837572U previously applied by the applicant. The voltage compensation module 3 is arranged between the contactor 2 and the input winding of the isolation transformer 4, and is used to perform voltage compensation on the three-phase input voltage of the mains power supply to ensure that the three-phase input voltage of the isolation transformer 4 remains stable, so as to ensure that its output voltage remains stable, so as to provide a stable power supply voltage for the load. The input sampling voltage transformer 1, the contactor 2, and the voltage compensation module 3 are all electrically connected to the controller. The controller is used to control the contactor 2 to close or open, and is also used to control the compensation voltage of the voltage compensation module 3 according to the monitoring result of the input sampling voltage transformer 1, so that the input voltage and output voltage of the isolation transformer 4 remain stable. It can be understood that the controller can control the voltage compensation module 3 to output a compensation voltage with the same frequency, phase-locked, and variable amplitude according to the monitoring results of the three-phase voltage of the input sampling voltage transformer 1. For example, when it is monitored that the three-phase input voltage has a voltage dip or voltage interruption, the voltage compensation module 3 can be controlled to output a compensation voltage with the same frequency, the same phase, and a certain amplitude, so that the compensation voltage is superimposed on the three-phase input voltage of the mains power supply, so that the input voltage of the isolation transformer 4 remains stable, that is, the input voltage waveform remains a stable sine waveform; and when it is monitored that the three-phase input voltage has a voltage surge, the voltage compensation module 3 is controlled to output a compensation voltage with the same frequency, opposite phase, and a certain amplitude, so that the compensation voltage cancels out the three-phase input voltage of the mains power supply, so that the input voltage of the isolation transformer 4 remains stable, that is, the input voltage waveform remains a stable sine waveform.

[0023] It can be understood that for the power filter with voltage anomaly compensation function in this embodiment, by respectively arranging input sampling voltage transformers 1 on three input phase lines of the mains power supply, voltage anomaly fluctuations such as voltage sags, voltage surges, and voltage interruptions of each phase voltage can be monitored. A voltage compensation module 3 is arranged before the input winding of the isolation transformer 4. The voltage compensation module 3 can output a compensation voltage with the same frequency, phase-locked, and adjustable amplitude. The controller can control the compensation voltage of the voltage compensation module 3 according to the monitoring results of the three-phase voltage, so that the compensation voltage is superimposed or offset with the three-phase input voltage of the mains power supply, so as to keep the input voltage and output voltage of the isolation transformer 4 stable, realizing the function of automatic voltage anomaly compensation and providing a power supply with stable voltage for the load.

[0024] Among them, the voltage compensation module 3 includes a three-phase rectifier ZL1, a first DC capacitor C1, a second DC capacitor C2, three IGBT modules PM, and three compensation coils L2. The input end of the three-phase rectifier ZL1 is connected to three input phase lines of the mains power supply and is used to convert alternating current into direct current. The first DC capacitor C1 and the second DC capacitor C2 are connected in series to form a DC energy storage module. The output end of the three-phase rectifier ZL1 is connected to the DC energy storage module. The three IGBT modules PM are connected to the DC energy storage module in parallel. The three compensation coils L2 are respectively arranged on three input phase lines of the mains power supply. The first end of each compensation coil L2 is connected to the middle point of the series connection of the first DC capacitor C1 and the second DC capacitor C2, and the other end is respectively connected to the output ends of the three IGBT modules PM. The three IGBT modules PM are all electrically connected to the controller, and the compensation voltage waveform output by each IGBT module PM is modulated by the controller. Among them, the three-phase rectifier ZL1 preferably adopts a three-phase bridge rectifier, and the first DC capacitor C1 and the second DC capacitor C2 adopt large-capacity supercapacitors.

[0025] It can be understood that the voltage compensation module 3 of this application converts the alternating current of the mains power supply into direct current through the three-phase rectifier ZL1, thereby charging the two DC capacitors. When it is monitored that any one of the input voltages of the mains power supply has a voltage anomaly fluctuation, the controller controls the corresponding IGBT module PM to start working. The two DC capacitors discharge to provide electrical energy for the inverter. The corresponding IGBT module PM generates a compensation voltage with the same frequency, phase-locked, and adjustable amplitude on the corresponding compensation coil L2, thereby performing single-phase compensation on the input voltage of this phase of the mains power supply, and independent compensation for each phase and automatic balance of the three-phase voltage can be realized. Among them, due to the use of IGBT for dynamic compensation, when the three-phase voltage of the mains power supply has flicker or voltage drop, the inverter compensates at a speed less than 1 ms, and the response speed is fast.

[0026] Optionally, the voltage compensation module 3 further includes a first discharge resistor R4 and a second discharge resistor R5. The first end of the first discharge resistor R4 is connected to the positive terminal of the first DC capacitor C1, and the second end is connected to the negative terminal of the first DC capacitor C1. The first end of the second discharge resistor R5 is connected to the positive terminal of the second DC capacitor C2, and the second end is connected to the negative terminal of the second DC capacitor C2. The first discharge resistor R4 and the second discharge resistor R5 are used to provide discharge circuits for the first DC capacitor C1 and the second DC capacitor C2 respectively when the power filter stops working. It can be understood that when the power filter stops working, since the IGBT module PM stops working, the two DC capacitors still maintain a high voltage state, which will shorten the service life of the DC capacitors. At this time, the two discharge resistors R4 and R5 can be used for discharging respectively, which is beneficial to improving the service life of the DC capacitors.

[0027] Optionally, the voltage compensation module 3 further includes a fuse FU1 connected in series between the DC energy storage module and the IGBT module, which can play a role in overcurrent protection. When the discharge current of the two DC capacitors exceeds the limit, the fuse FU1 will burn out to automatically disconnect the power supply line of the IGBT module and prevent the IGBT module from being burned out.

[0028] Optionally, the voltage compensation module 3 further includes a Hall current detector CT1 connected in series between the DC energy storage module and the IGBT module, which can safely monitor the DC current output by the two DC capacitors. Once an abnormal output DC current is detected, an alarm reminder can be issued, or the contactor 2 can be controlled to disconnect.

[0029] Optionally, a first temperature sensor RT1 is provided in at least one IGBT module PM. The first temperature sensor RT1 is electrically connected to the controller, and the working temperature of the IGBT module PM can be monitored through the first temperature sensor RT1 to prevent the IGBT module PM from overheating. Preferably, a first temperature sensor RT1 is provided in each IGBT module PM.

[0030] In addition, the power filter with voltage anomaly compensation function further includes a dual-power switching switch 5 disposed between the output winding of the isolation transformer 4 and the load. The dual-power switching switch 5 is respectively connected to the output winding of the isolation transformer 4 and the commercial power. The dual-power switching switch 5 is electrically connected to the controller, and the controller is further configured to control the switching action of the dual-power switching switch 5. For example, when the isolation transformer 4 fails, the controller can control the dual-power switching switch 5 to switch to be connected to the commercial power to facilitate emergency power supply for the load; when the isolation transformer 4 is operating normally, the controller controls the dual-power switching switch 5 to switch to be connected to the output winding of the isolation transformer 4, so as to provide safe alternating current for the load. Optionally, output voltage transformers 6 are respectively disposed on the three-phase output lines of the isolation transformer 4 to facilitate single-phase voltage monitoring of the three-phase output voltage of the isolation transformer 4. The output voltage transformers 6 are electrically connected to the controller. When any one of the output voltages of the isolation transformer 4 is monitored to be abnormal, the controller controls the dual-power switching switch 5 to switch to the commercial power for emergency power supply. Optionally, filter capacitors C3, C4, and C5 are respectively disposed on the three-phase output lines of the isolation transformer 4 to facilitate filtering of the output voltages of each phase of the isolation transformer 4. Among them, the first ends of the filter capacitors C3, C4, and C5 are respectively connected to the three-phase output lines of the isolation transformer 4, and the other ends are all connected to the output neutral line of the isolation transformer 4. Optionally, current transformers CT2 are respectively disposed on the three-phase output lines of the isolation transformer 4 to facilitate single-phase current monitoring of the three-phase output current of the isolation transformer 4, ensuring that the output current of each phase is less than the human body safety current value.

[0031] In addition, arc suppression resistors are connected in parallel at both ends of each contactor 2. Specifically, arc suppression resistors R1, R2, and R3 are respectively connected in parallel at both ends of the three contactors 2. The resistance values of the arc suppression resistors R1, R2, and R3 are relatively large. When the contactor 2 is disconnected, a small current path is provided for the commercial power supply. When the contactor 2 is closed, the arc spark generated at the moment of closing the contactor 2 can be reduced.

[0032] In addition, circuit breakers QF are disposed on the three input phase lines of the commercial power and / or the three output phase lines of the isolation transformer 4 to play a role in overcurrent protection. In addition, reactors L1 are further disposed on the three input phase lines of the commercial power, which can limit the voltage drop on the grid side during the commutation of the converter and the current rise rate and voltage rise rate of the thyristor. In addition, a leakage current transformer 7 is disposed on the output line of the isolation transformer 4 for monitoring the leakage current. The leakage current transformer 7 is electrically connected to the controller. When the leakage current is monitored, an alarm reminder can be issued, or the contactor 2 can be controlled to disconnect.

[0033] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. For those skilled in the art, the present utility model may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. An electric energy filter with voltage anomaly compensation function, characterized in that: The invention comprises an input sampling voltage transformer (1), a contactor (2), a voltage compensation module (3), an isolation transformer (4) and a controller. The input sampling voltage transformer (1) is respectively arranged on three input phase lines of the mains power supply and is used to monitor the three-phase input voltage of the mains power supply. The contactor (2) is respectively arranged on the three input phase lines of the mains power supply and is used to control the on and off of the mains power supply line. The input winding and the output winding of the isolation transformer (4) are respectively connected to the contactor (2) and the load and are used to filter the alternating current of the mains power supply. The voltage compensation module (3) is used to filter the alternating current of the mains power supply. The block (3) is arranged between the contactor (2) and the input winding of the isolation transformer (4), and is used to perform voltage compensation on the three-phase input voltage of the mains. The input sampling voltage transformer (1), the contactor (2) and the voltage compensation module (3) are all electrically connected to a controller. The controller is used to control the contactor (2) to close or open, and is also used to control the compensation voltage of the voltage compensation module (3) according to the monitoring result of the input sampling voltage transformer (1), so as to keep the input voltage and output voltage of the isolation transformer (4) stable.

2. The electric energy filter with voltage anomaly compensation function according to claim 1, characterized in that: The voltage compensation module (3) comprises a three-phase rectifier ZL1, a first DC capacitor C1, a second DC capacitor C2, three IGBT modules PM and three compensation coils L2. The input end of the three-phase rectifier ZL1 is connected to three input phase lines of the mains for converting AC into DC. The first DC capacitor C1 and the second DC capacitor C2 are connected in series to form a DC energy storage module. The output end of the three-phase rectifier ZL1 is connected to the DC energy storage module. The three IGBT modules PM are connected to the DC energy storage module in parallel. The three compensation coils L2 are respectively arranged on the three input phase lines of the mains. The first end of each compensation coil L2 is connected to the middle point of the series connection of the first DC capacitor C1 and the second DC capacitor C2, and the other end is respectively connected to the output ends of the three IGBT modules PM. The three IGBT modules PM are all electrically connected to the controller.

3. The electric energy filter with voltage anomaly compensation function as claimed in claim 2, characterized in that: The voltage compensation module (3) further comprises a first discharge resistor R4 and a second discharge resistor R5, wherein a first end of the first discharge resistor R4 is connected to a positive terminal of the first DC capacitor C1, and a second end is connected to a negative terminal of the first DC capacitor C1, and a first end of the second discharge resistor R5 is connected to a positive terminal of the second DC capacitor C2, and a second end is connected to a negative terminal of the second DC capacitor C2, and the first discharge resistor R4 and the second discharge resistor R5 are used to provide discharge circuits for the first DC capacitor C1 and the second DC capacitor C2 respectively when the electric energy filter stops working.

4. The electric energy filter with voltage anomaly compensation function as claimed in claim 2, characterized in that: The voltage compensation module (3) further comprises a fuse FU1 connected in series between the DC energy storage module and the IGBT module.

5. The electric energy filter with voltage anomaly compensation function as claimed in claim 2, characterized in that: The voltage compensation module (3) also includes a Hall current detector CT1 connected in series between the DC energy storage module and the IGBT module.

6. The electric energy filter with voltage anomaly compensation function as claimed in claim 2, characterized in that: At least one IGBT module PM is provided with a first temperature sensor RT1 , and the first temperature sensor RT1 is electrically connected to the controller.

7. The electric energy filter with voltage anomaly compensation function according to claim 1, characterized in that: It also includes a dual power switch (5) arranged between the output winding of the isolation transformer (4) and the load, the dual power switch (5) being connected to the output winding of the isolation transformer (4) and the mains respectively, the dual power switch (5) being electrically connected to a controller, and the controller being further used to control the switching action of the dual power switch (5).

8. The electric energy filter with voltage anomaly compensation function as claimed in claim 1, characterized in that: Both ends of each contactor (2) are connected in parallel with an arc-extinguishing resistor.

9. The electric energy filter with voltage anomaly compensation function as claimed in claim 1, characterized in that: Circuit breakers QF are provided on the three input phase lines of the mains electricity and / or the three output phase lines of the isolation transformer (4).

10. The electric energy filter with voltage anomaly compensation function according to claim 1, characterized in that: Reactors L1 are also provided on the three input phase lines of the mains.

Images