CN113363951A - Direct current residual current protector, protection method and direct current power supply system - Google Patents
Direct current residual current protector, protection method and direct current power supply system Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/268—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for dc systems
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
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Abstract
The application relates to a direct current residual current protector, a protection method and a direct current power supply system. The control device obtains alternating current leakage current in the direct current circuit according to residual current detected by the current sensor, obtains a compensation power value according to the alternating current leakage current, and controls the alternating current counteracting device to generate alternating current according to the compensation power value so as to counteract the alternating current leakage current in the direct current circuit, so that the direct current residual current can be detected by the current sensor, and interference of the alternating current leakage current on the RCD can be effectively avoided.
Description
Technical Field
The application relates to the technical field of power supply equipment, in particular to a direct current residual current protector, a protection method and a direct current power supply system.
Background
With the direct current of the equipment in the civil scene, the advantage of low-voltage direct current power supply is shown, and therefore the direct current power supply system in the civil scene is gradually formed. The application of civil scenes means that electric shock protection measures need to be added to ensure the safety of human bodies, and direct Current (Residual Current) Residual Current protection (RCD) is a crucial measure, and when a human body gets an electric shock, a system generates direct Current Residual Current, and the RCD just utilizes the direct Current Residual Current to protect the safety of people.
However, in actual operation, the dc power supply system also has ac leakage current, which adversely affects the normal operation of the RCD. How to avoid interference of alternating current leakage current on the RCD is an urgent problem to be solved.
Disclosure of Invention
Therefore, it is necessary to provide a dc residual current protector, a protection method and a dc power supply system for solving the problem that the ac leakage current in the dc power supply system adversely affects the normal operation of the RCD, so as to achieve the effect of effectively avoiding the interference of the ac leakage current on the RCD.
A direct current residual current protector comprises a current sensor, an alternating current counteracting device and a control device, wherein the current sensor and the alternating current counteracting device are arranged on a direct current line of a direct current power supply system, and the control device is connected with the current sensor and the alternating current counteracting device;
the control device is used for acquiring alternating current leakage current in the direct current circuit according to residual current detected by the current sensor, acquiring a compensation power supply value according to the alternating current leakage current, and controlling the alternating current counteracting device to generate alternating current according to the compensation power supply value so as to counteract the alternating current leakage current in the direct current circuit.
In one embodiment, the control device performs PI (Proportional Integral and Integral) calculation according to the ac leakage current to obtain a compensation power value.
In one embodiment, the control device takes the alternating leakage current as the controlled quantity of a PI control loop, the PI control loop aims at controlling the alternating component in the measuring winding of the current sensor to be 0, and PI calculation is carried out to output a compensation power supply value.
In one embodiment, the control device performs fast fourier transform on the residual current measured by the current sensor to obtain the ac leakage current.
In one embodiment, the control device filters residual current measured by the current sensor to obtain alternating leakage current.
In one embodiment, the ac cancellation device includes a compensation winding and a compensation power supply, and the compensation power supply connects the compensation winding and the control device.
In one embodiment, the dc residual current protector further comprises an executing device connected to the control device, wherein the executing device is arranged in the dc power supply system; the control device is also used for disconnecting the power supply of the direct current power supply system through the execution device when the direct current residual current detected by the current sensor is larger than a preset threshold value.
A direct current residual current protection method comprises the following steps:
acquiring residual current detected by a current sensor; the current sensor is arranged on a direct current line of the direct current power supply system;
obtaining alternating current leakage current in the direct current circuit according to the residual current;
obtaining a compensation power supply value according to the alternating current leakage current, and controlling an alternating current counteracting device to generate alternating current according to the compensation power supply value so as to counteract the alternating current leakage current in the direct current circuit; the alternating current offset device is arranged on a direct current line of the direct current power supply system.
A direct current power supply system comprises the direct current residual current protector.
In one embodiment, the dc power supply system further comprises a dc line connecting the power source and the powered device.
According to the direct current residual current protector, the protection method and the direct current power supply system, the control device obtains the alternating current leakage current in the direct current circuit according to the residual current detected by the current sensor, obtains the compensation power supply value according to the alternating current leakage current, and controls the alternating current offset device to generate alternating current according to the compensation power supply value so as to offset the alternating current leakage current in the direct current circuit, so that the direct current residual current can be detected through the current sensor, and the interference of the alternating current leakage current on the RCD can be effectively avoided.
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In order to more clearly illustrate the technical solutions in the embodiments or the conventional technologies of the present application, the drawings used in the descriptions of the embodiments or the conventional technologies will be briefly introduced below, it is obvious that the drawings in the following descriptions are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a block diagram of a dc residual current protector according to an embodiment;
FIG. 2 is a schematic diagram of a PI control loop for controlling the AC component of the residual current measurement to be zero in one embodiment;
FIG. 3 is a schematic diagram of the current sensor and AC cancellation device in one embodiment;
FIG. 4 is a flow chart of a DC residual current protection method according to an embodiment;
fig. 5 is a schematic view of an application scenario of the dc residual current protector in an embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
Unless defined otherwise, all 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. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
It will be understood that, as used herein, the terms "first," "second," and the like may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, a first resistance may be referred to as a second resistance, and similarly, a second resistance may be referred to as a first resistance, without departing from the scope of the present application. The first resistance and the second resistance are both resistances, but they are not the same resistance.
It is to be understood that "connection" in the following embodiments is to be understood as "electrical connection", "communication connection", and the like if the connected circuits, modules, units, and the like have communication of electrical signals or data with each other.
As used herein, the singular forms "a", "an" and "the" may include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises/comprising," "includes" or "including," etc., specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Also, as used in this specification, the term "and/or" includes any and all combinations of the associated listed items.
In one embodiment, a dc residual current protector is provided, which is suitable for solving the problem of inaccurate action caused by ac leakage current of a dc RCD in a civil low-voltage dc power supply system. As shown in fig. 1, the dc residual current protector includes a current sensor 110, an ac cancellation device 120, and a control device 130, wherein the current sensor 110 and the ac cancellation device 120 are disposed on a dc line of a dc power supply system, and the control device 130 is connected to the current sensor 110 and the ac cancellation device 120. The control device 130 is configured to obtain an ac leakage current in the dc line according to the residual current detected by the current sensor 110, obtain a compensation power value according to the ac leakage current, and control the ac cancellation device 120 to generate ac power according to the compensation power value to cancel the ac leakage current in the dc line.
Specifically, the current sensor 110 may employ a current transformer, and employ the fluxgate principle to realize the detection of the micro direct current. The ac cancellation device 120 and the current sensor 110 are disposed on the dc line, and ac current generated by the ac cancellation device 120 cancels ac leakage current in the dc line, so that the current sensor 110 can detect dc residual current without being affected by the ac leakage current.
The Control device 130 may be an MCU (Micro Control Unit), a CPU (Central Processing Unit), or the like. The manner of obtaining the ac leakage current in the dc line by the control device 130 is not unique, and may be that after the current sensor 110 detects a residual current containing an ac component, the residual current is converted or filtered, the ac component is extracted to obtain an ac measurement value, and then a current having the same magnitude and the opposite direction as the ac measurement value is injected into the ac cancellation device 120, so as to cancel the ac leakage current in the dc line, and then the dc residual current is detected by the current sensor 110.
In the dc residual current protector, the control device 130 obtains the ac leakage current in the dc line according to the residual current detected by the current sensor 110, obtains the compensation power value according to the ac leakage current, and controls the ac cancellation device 120 to generate the ac power according to the compensation power value, so as to cancel the ac leakage current in the dc line, thereby detecting the dc residual current by the current sensor 110, and effectively avoiding the interference of the ac leakage current to the RCD.
In one embodiment, the control device 130 performs a fast fourier transform on the residual current measured by the current sensor to obtain the ac leakage current. The residual current measured by the current sensor 110 is subjected to Fast Fourier Transform (FFT), and then the ac portion of the main frequency band is obtained, so as to obtain the ac leakage current.
In another embodiment, the control device 130 filters the residual current measured by the current sensor to obtain the ac leakage current. Specifically, after the residual current is measured by the current sensor 110, the ac component in the residual current can be directly separated by using a filter, so as to obtain the ac leakage current.
In one embodiment, the control device 130 performs a PI calculation based on the ac leakage current to obtain the compensation power value. The PI regulation is a linear control, a control deviation is formed according to a given value and an actual output value, the proportion and the integral of the deviation are linearly combined to form a control quantity, a controlled object is controlled, and the regulation control is accurate and reliable. In the present embodiment, the control device 130 outputs the compensation power supply value by performing PI calculation with the ac leakage current as the controlled variable of the PI control loop targeting the ac component in the measurement winding of the control current sensor 110 as 0.
Specifically, as shown in fig. 2, an FFT or a filter is used to obtain an ac component in the residual current as a controlled quantity of the PI control loop; the PI control loop aims to control the ac component in the measurement winding of the current sensor 110 to be 0, the feedback quantity is the ac component value, and the PI calculates to obtain the compensation power supply value, so that the ac component generated by the ac cancellation device 120 can be cancelled out by the ac leakage current.
The specific structure of ac cancellation device 120 is not exclusive, and in one embodiment ac cancellation device 120 includes a compensation winding and a compensation power source connected to compensation winding and control device 130.
Specifically, as shown in fig. 3, the compensation winding may be disposed on the same iron core as the measurement winding of the current sensor 110, after the residual current is detected by the measurement winding of the current sensor 110, when the control device 130 performs PI calculation, first, the FFT or the filter is used to obtain the ac residual current in the residual current as a given value (i.e., a controlled quantity), an actual output value (i.e., a feedback quantity) is an ac component output by the compensation power supply on the compensation winding, a control loop aims to control the ac component in the measurement winding of the current sensor 110 to be 0, specifically, the compensation power supply value is output by PI calculation, and a current having the same magnitude and the opposite direction to the ac measured value is injected on the compensation winding by the compensation power supply, so that the ac component is in cancellation effect.
In another embodiment, the ac cancellation device includes a common mode core, a common mode filter inductor, and an auxiliary winding, the common mode filter inductor and the auxiliary winding are disposed on the common mode core, the common mode filter inductor is connected in series to the dc line, and the auxiliary winding is connected to the control device.
In order to avoid the influence of the ac leakage current on the detection of the dc residual current in the dc power supply system, a common mode filter may be connected in series to the dc line to suppress the ac leakage current. However, when a dc residual current occurs, the common mode filter may also be affected, and the common mode filter needs to have a larger dc residual current bearing capability, and also needs to maintain the suppression effect of the ac leakage current. Therefore, in this embodiment, the ac cancellation device 120 is designed to add an auxiliary winding to the common-mode core based on the common-mode filter, and the current of the auxiliary winding is obtained by performing PI calculation compensation by the control device 130.
In particular, the ac leakage current is related to the switching frequency of the power converter in the dc power supply system, and by this feature, the residual current I detectable by the current sensor 110RCAnalyzing and calculating the component I related to the switching frequencySAccording to ISIs used for generating a compensation current IC. By continuously dependent on the residual current IRCAnd ISAdjusting the compensating current ICUntil a residual current IRCIn (II)SAnd minimum.
In one embodiment, the dc residual current protector further comprises a signal amplifier, and the control device 130 is connected to the current sensor 110 through the signal amplifier. The signal detected by the current sensor 110 is amplified by the signal amplifier and then transmitted to the control device 130, which facilitates the signal analysis of the control device 130.
In addition, in one embodiment, the dc residual current protector further includes an executing device connected to the control device 130, the executing device is disposed in the dc power supply system; the control device 130 is further configured to disconnect the power supply of the dc power supply system through the execution device when the dc residual current detected by the current sensor is greater than a preset threshold.
The value of the preset threshold is not unique and can be set according to actual requirements. Specifically, the executing device may be a circuit breaker, and when the dc residual current is greater than the preset threshold, the controlling device 130 controls the circuit breaker to be turned off, so as to trigger protection to turn off the power supply, thereby ensuring personal safety.
In one embodiment, as shown in fig. 4, there is further provided a dc residual current protection method, including:
step S110: and acquiring residual current detected by the current sensor. The current sensor is arranged on a direct current line of the direct current power supply system. The current sensor can adopt a current transformer and adopts the fluxgate principle to realize the detection of the micro direct current.
Step S120: and obtaining the alternating current leakage current in the direct current line according to the residual current. Specifically, the residual current measured by the current sensor may be subjected to fast fourier transform to obtain the ac leakage current. In addition, the residual current measured by the current sensor can be filtered to obtain the alternating current leakage current.
Step S130: and obtaining a compensation power supply value according to the alternating current leakage current, and controlling the alternating current counteracting device to generate alternating current according to the compensation power supply value so as to counteract the alternating current leakage current in the direct current circuit. The alternating current offset device is arranged on a direct current line of the direct current power supply system.
Specifically, the compensation power supply value can be obtained by performing PI calculation according to the ac leakage current. And taking the alternating current leakage current as the controlled quantity of a PI control loop, wherein the PI control loop aims at controlling the alternating current component in a measuring winding of the current sensor to be 0, and performing PI calculation to output a compensation power supply value. The specific structure of the ac cancellation device is not exclusive, and the ac cancellation device may be a structure including a compensation winding and a compensation power supply, or a structure including a common-mode magnetic core, a common-mode filter inductor, and an auxiliary winding.
It should be noted that, for specific limitations of the dc residual current protection method, reference may be made to the above limitations of the dc residual current protector, and details are not described herein again.
According to the direct current residual current protection method, the alternating current leakage current in the direct current circuit is obtained according to the residual current detected by the current sensor, the compensation power supply value is obtained according to the alternating current leakage current, the alternating current counteracting device is controlled to generate alternating current according to the compensation power supply value so as to counteract the alternating current leakage current in the direct current circuit, therefore, the direct current residual current can be detected by the current sensor, and the interference of the alternating current leakage current on the RCD is effectively avoided.
In one embodiment, a dc power supply system is also provided, which includes the dc residual current protector. Further, the direct current power supply system further comprises a direct current line, and the direct current line is connected with the power supply and the electric equipment. And the direct current output by the power supply is transmitted to the electric equipment through the direct current line for power supply. The direct current residual current protector comprises a current sensor, an alternating current counteracting device and a control device, wherein the current sensor and the alternating current counteracting device are arranged on a direct current line of a direct current power supply system, and the control device is connected with the current sensor and the alternating current counteracting device.
The current sensor may employ a current transformer. The control device may be an MCU, a CPU, or the like. The control device may be configured to convert or filter the residual current including the ac component after detecting the residual current by the current sensor, extract the ac component to obtain an ac measurement value, and inject a current having a same magnitude and an opposite direction as the ac measurement value into the ac cancellation device, so as to cancel the ac leakage current in the dc line, and then detect the dc residual current by the current sensor.
In one embodiment, the control device performs fast fourier transform on the residual current measured by the current sensor to obtain the ac leakage current. And performing fast Fourier transform on the residual current measured by the current sensor, and then acquiring the alternating current part of the main frequency band to obtain the alternating current leakage current.
In another embodiment, the control device filters a residual current measured by the current sensor to obtain an ac leakage current. After the current sensor measures and obtains the residual current, the alternating current component in the residual current is directly separated by using the filter, and the alternating current leakage current is obtained.
In one embodiment, the control device performs a PI calculation based on the ac leakage current to obtain the compensation power supply value. The PI regulation forms a control deviation according to a given value and an actual output value, the proportion and the integral of the deviation form a control quantity through linear combination, a controlled object is controlled, and the regulation control is accurate and reliable. In this embodiment, the control device performs PI calculation to output a compensation power supply value by using the ac leakage current as the controlled variable of the PI control loop, targeting the control current sensor to control the ac component in the measurement winding to 0.
Specifically, an alternating current component in the residual current is obtained by using an FFT or a filter and is used as the controlled quantity of a PI control loop; the PI control loop aims at controlling the alternating current component in the measuring winding of the current sensor to be 0, the feedback quantity is the alternating current component value, and the PI calculates to obtain a compensation power supply value so that the alternating current component generated by the alternating current offset device can be offset with the alternating current leakage current.
In one embodiment, the ac cancellation means comprises a compensation winding and a compensation power supply, the compensation power supply connecting the compensation winding and the control means. The compensation winding and the measurement winding of the current sensor can be arranged on the same iron core, after the residual current is obtained through the detection of the measurement winding of the current sensor, when the control device performs PI calculation, the FFT or the filter is firstly utilized to obtain the alternating current residual current in the residual current as a given value (namely controlled quantity), an actual output value (namely feedback quantity) is an alternating current component output by the compensation power supply on the compensation winding, a control loop aims at controlling the alternating current component in the measurement winding of the current sensor to be 0, the compensation power supply value is specifically realized through PI calculation output, and the compensation winding is injected with a current which is equal to the alternating current measured value and opposite in direction through the compensation power supply, so that the alternating current component is in a cancellation effect.
In another embodiment, the ac cancellation device includes a common mode core, a common mode filter inductor, and an auxiliary winding, the common mode filter inductor and the auxiliary winding are disposed on the common mode core, the common mode filter inductor is connected in series to the dc line, and the auxiliary winding is connected to the control device. In this embodiment, the ac cancellation device adopts a design of adding an auxiliary winding to the common-mode magnetic core on the basis of the common-mode filter, and the current of the auxiliary winding is obtained by performing PI calculation compensation by the control device.
In one embodiment, the dc residual current protector further comprises a signal amplifier, and the control device is connected with the current sensor through the signal amplifier.
In addition, in one embodiment, the direct current residual current protector further comprises an execution device connected with the control device, and the execution device is arranged in the direct current power supply system; the control device is also used for disconnecting the power supply of the direct current power supply system through the execution device when the direct current residual current detected by the current sensor is larger than a preset threshold value.
According to the direct current power supply system, alternating current leakage current in a direct current line is obtained according to residual current detected by the current sensor, a compensation power value is obtained according to the alternating current leakage current, the alternating current counteracting device is controlled to generate alternating current according to the compensation power value so as to counteract the alternating current leakage current in the direct current line, and therefore the direct current residual current can be detected by the current sensor, and interference of the alternating current leakage current on the RCD is effectively avoided.
In order to better describe the dc residual current protector and the dc power supply system, the following detailed explanation is provided with reference to specific embodiments.
The RCD is used as an important link of electric shock protection, and has wide application prospect in the scenes of electric vehicle charging facilities (charging piles and charging stations), photovoltaic power generation, civil buildings, municipal road lighting, data center direct current power supply systems and the like. The civil direct current power supply system is only in an initial test and demonstration stage, the direct current RCD product is not mature, but according to analysis, alternating current leakage current in the direct current system can have adverse effects on the normal operation of the direct current RCD.
As shown in FIG. 5, when an electric shock accident occurs, a current flows through a human bodyITWith residual current IRCIs detected by the RCD according to IRCAnd judging the severity of the danger, triggering protection when the severity reaches a limit value, and disconnecting a power supply to ensure personal safety.
The direct current RCD residual current protector mainly comprises a current transformer, a judging element, an executing element, an electronic signal amplifier, a testing device and the like, and the detection of micro direct current is generally realized by adopting a fluxgate principle. Because there are certain ripple voltage and common mode voltage in the DC power supply, even do not take place the electric shock accident, also can form some alternating current leakage currents through cable to ground stray capacitance, these leakage currents also represent the form of residual current to be detected by RCD's current transformer, to direct current residual current's detection and analysis production interference, and then influence direct current RCD's detection and protection precision.
Based on this, the application provides a scheme that reduces alternating current leakage current and detects the influence to direct current residual current, can reduce the degree that direct current supply system RCD received alternating current leakage current influence. Because the alternating current leakage current only plays a role in interference on the direct current RCD, no matter how large the alternating current leakage current is measured by the direct current RCD, the alternating current component in the residual current is counteracted by a certain method, and the influence of the alternating current leakage current is avoided.
As shown in fig. 3, the RCD measures the phasor sum of currents of the positive and negative poles through magnetic induction to obtain the system residual current, adds a compensation winding on the basis of the original measurement winding, and injects a current with the same magnitude and the opposite direction as the alternating current measurement value into the compensation winding through a compensation power supply to eliminate the alternating current component in the compensation winding. Firstly, extracting alternating current components in residual current measured by a measuring winding to be used as controlled quantity of a PI control loop shown in figure 2; in fig. 2, the PI control loop aims to control the ac component in the measurement winding to be 0, the feedback quantity is the ac component value, and the PI calculates and outputs the compensation power supply value, so that the ac component in the compensation winding can be cancelled out by the ac residual current. The residual current of human body when electric shock is direct current, and the frequency of alternating current leakage current is high frequency, generally above 10kHz, so the method for obtaining alternating current residual current can be divided into two methods: firstly, performing fast Fourier transform on the measured residual current, and then acquiring an alternating current part of a main frequency band; secondly, the alternating current component in the water is directly separated by using a filter.
In addition, a design of adding an auxiliary winding to the common mode core may be adopted on the basis of the common mode filter. According to residual current I detected by current sensorRCAnalyzing to calculate component I related to switching frequencyS. According to ISIs used for generating a compensation current ICContinuously according to the residual current IRCAnd ISAdjusting the compensating current ICUntil a residual current IRCIn (II)SAnd minimum.
In order to avoid the influence of alternating current leakage current, the alternating current component in the residual current is eliminated when the residual current is measured, so that the influence of the residual current on the action of a direct current RCD is avoided.
In the description herein, references to the description of "some embodiments," "other embodiments," "desired embodiments," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, a schematic description of the above terminology may not necessarily refer to the same embodiment or example.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A direct current residual current protector is characterized by comprising a current sensor, an alternating current counteracting device and a control device, wherein the current sensor and the alternating current counteracting device are arranged on a direct current line of a direct current power supply system, and the control device is connected with the current sensor and the alternating current counteracting device;
the control device is used for acquiring alternating current leakage current in the direct current circuit according to residual current detected by the current sensor, acquiring a compensation power supply value according to the alternating current leakage current, and controlling the alternating current counteracting device to generate alternating current according to the compensation power supply value so as to counteract the alternating current leakage current in the direct current circuit.
2. A dc residual current protector according to claim 1, wherein said control means performs PI calculations based on said ac leakage current to obtain a compensated power supply value.
3. A dc residual current protector according to claim 2, wherein the control means is arranged to perform PI calculation to output the compensated power supply value by using the ac leakage current as a controlled quantity of a PI control loop targeting the ac component in the measurement winding of the control current sensor as 0.
4. A dc residual current protector according to claim 1, wherein the control means performs a fast fourier transform on the residual current measured by the current sensor to obtain an ac leakage current.
5. A dc residual current protector according to claim 1, wherein the control means filters the residual current measured by the current sensor to obtain an ac leakage current.
6. A dc residual current protector according to claim 1, wherein said ac cancellation means comprises a compensation winding and a compensation power supply, said compensation power supply connecting said compensation winding and said control means.
7. A direct current residual current protector according to any one of claims 1-6, further comprising an execution device connected with said control device, said execution device being disposed in said direct current supply system; the control device is also used for disconnecting the power supply of the direct current power supply system through the execution device when the direct current residual current detected by the current sensor is larger than a preset threshold value.
8. A direct current residual current protection method is characterized by comprising the following steps:
acquiring residual current detected by a current sensor; the current sensor is arranged on a direct current line of the direct current power supply system;
obtaining alternating current leakage current in the direct current circuit according to the residual current;
obtaining a compensation power supply value according to the alternating current leakage current, and controlling an alternating current counteracting device to generate alternating current according to the compensation power supply value so as to counteract the alternating current leakage current in the direct current circuit; the alternating current offset device is arranged on a direct current line of the direct current power supply system.
9. A dc power supply system comprising a dc residual current protector according to any one of claims 1 to 7.
10. The dc power supply system of claim 9, further comprising a dc link connecting the power source and the powered device.
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| CN202110558189.6A CN113363951B (en) | 2021-05-21 | 2021-05-21 | Direct current residual current protector, protection method and direct current power supply system |
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| CN202110558189.6A CN113363951B (en) | 2021-05-21 | 2021-05-21 | Direct current residual current protector, protection method and direct current power supply system |
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| WO2023086545A1 (en) * | 2021-11-15 | 2023-05-19 | Medtronic, Inc. | Methods and apparatus for reducing leakage currents in cryo, radio-frequency, and pulsed-field ablation systems |
| CN117543503A (en) * | 2023-11-13 | 2024-02-09 | 重庆电道智能科技有限公司 | Leakage protector |
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| CN113363951B (en) | 2023-10-31 |
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