KR-102963921-B1 - SOLID STATE CIRCUIT BREAKER(SSCB), CURRENT SENSOR OF THE SSCB, AND CONTROL METHOD OF THE SSCB AND THE CURRENT SENSOR

KR102963921B1KR 102963921 B1KR102963921 B1KR 102963921B1KR-102963921-B1

Abstract

The present invention relates to a solid-state circuit breaker, wherein the invention includes a current sensor that detects the occurrence of an overcurrent according to a change in the magnitude of the current flowing into the solid-state circuit breaker, transmits a signal indicating the occurrence of the overcurrent to a control unit of the solid-state circuit breaker, and determines whether the overcurrent is a noise overcurrent or a fault current based on an integral value obtained by integrating the magnitude of the detected current over time elapsed after the occurrence of the overcurrent; and wherein the solid-state circuit breaker including the current sensor limits the gate voltage applied to the gate terminal of each solid-state switch when an overcurrent occurs to limit the amount of current that can be output from the solid-state switch, and controls the gate drivers of each solid-state switch to disconnect the load and the solid-state circuit breaker from the power system or restore the limited gate voltage according to the type of overcurrent determined by the current sensor.

Inventors

윤동진
심정욱
강성희
송웅협

Assignees

엘에스일렉트릭(주)

Dates

Publication Date: 20260511
Application Date: 20210329

Claims (16)

In a current sensor provided in a semiconductor circuit breaker, A current detection unit that detects a change in the magnitude of the current from the voltage of the current flowing into any one of the semiconductor switches of the above-mentioned semiconductor circuit breaker; As a result of detecting a change in the magnitude of the above current, an integrating unit that integrates the detected current magnitude according to the time elapsed from a first point in time when the current magnitude increased, when the current magnitude increases; and, It includes a detection control unit that transmits an overcurrent detection signal indicating the occurrence of an overcurrent to the control unit of the semiconductor circuit breaker when the current magnitude increases as a result of detection by the current detection unit, and transmits a fault current detection signal indicating the occurrence of a fault current to the control unit of the semiconductor circuit breaker based on a comparison result obtained by comparing a value accumulated according to the time elapsed since the first point in time according to the integration result of the integration unit with a preset threshold value. The above current sensor is, It further includes an initial charging circuit to prevent overcurrent from being detected by an inrush current that occurs when any one of the above semiconductor switches is turned on, and The above first point in time is, A current sensor characterized by the fact that, as an overcurrent greater than the overcurrent absorbed by the hardware in front of the current detection unit including the initial charging circuit occurs, the magnitude of the current flowing into any one of the semiconductor switches increases.
In paragraph 1, the current detection unit is, A current sensor characterized by further including a semiconductor current detection unit that detects a change in the magnitude of a current flowing in from a power system based on the voltage between the source terminal and the drain terminal of any one of the semiconductor switches according to the DESAT (Desaturation fault detection) method.
In paragraph 1, the detection control unit is, A current sensor characterized by further transmitting a current restoration signal to the control unit of the semiconductor circuit breaker, indicating that the current state has been restored, when the current level detected after the first point in time is restored to a normal level as a result of detection by the current detection unit.
In paragraph 1, the detection control unit is, A current sensor characterized by controlling the integration unit to calculate a value accumulated over a preset time period from the first point in time, and comparing the calculated value with the threshold value.
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A method for controlling a current sensor provided in a semiconductor circuit breaker, A step of detecting a change in the magnitude of the current from the voltage of the current flowing into any one of the semiconductor switches of the semiconductor circuit breaker; A step of transmitting an overcurrent detection signal to the control unit of the semiconductor circuit breaker to indicate the occurrence of an overcurrent when the magnitude of the current increases as a result of the above detection; A step of integrating the magnitude of the detected current according to the time elapsed from the first point in time when the increase in the magnitude of the current is detected; A step of comparing the value accumulated during the time elapsed since the first point in time according to the integration result with a preset threshold value; and, Based on the comparison result above, if the accumulated value is greater than or equal to the threshold value, the method includes the step of transmitting a fault current detection signal indicating the occurrence of a fault current to the control unit of the semiconductor circuit breaker. The above current sensor is, It further includes an initial charging circuit to prevent overcurrent from being detected by an inrush current that occurs when any one of the above semiconductor switches is turned on, and The above first point in time is, A method for controlling a current sensor, characterized in that the magnitude of the current flowing into any one of the semiconductor switches increases as an overcurrent greater than the overcurrent absorbed by the hardware of the current sensor including the initial charging circuit occurs.
In paragraph 6, the change in the magnitude of the above current is, A control method for a current sensor characterized by detecting based on the voltage between the source terminal and the drain terminal of any one of the semiconductor switches according to the DESAT (Desaturation fault detection) method.
In paragraph 6, The step of comparing the above accumulated value with a preset threshold value is If the accumulated value is less than the threshold value as a result of the comparison above, a step of re-detecting a change in the magnitude of the current flowing into any one of the semiconductor switches; and, A method for controlling a current sensor, characterized by further including the step of transmitting a current restoration signal indicating that the current state has been restored according to the above re-detection result to the control unit of the semiconductor circuit breaker.
In paragraph 6, The step of integrating the magnitude of the detected current is, The step of integrating the magnitude of the detected current from the first point in time until a preset time has elapsed, and The step of comparing the above accumulated value with a preset threshold value is A method for controlling a current sensor characterized by a step of comparing a value accumulated over a preset time with a preset threshold value.
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In semiconductor circuit breakers, A cutoff switch that physically connects or isolates the semiconductor circuit breaker and the load from the power system; A semiconductor switch unit comprising a plurality of semiconductor switches, wherein the maximum magnitude of the current supplied from the power system to the load is determined according to the gate voltage applied to the gate terminal; A plurality of gate drivers that apply a gate voltage to each gate terminal of the plurality of semiconductor switches; A current sensor for sensing current flowing in from the above power system; and, When an overcurrent detection signal indicating the occurrence of an overcurrent is received from the current sensor, the plurality of gate drivers are controlled so that a limited gate voltage is applied to each gate terminal, and The control unit includes, when the gate voltage is limited, a fault current detection signal indicating the occurrence of a fault current is received from the current sensor, controlling the cutoff switch to isolate the semiconductor circuit breaker and the load from the power system. The above current sensor is, A current detection unit that detects a change in the magnitude of the current from the voltage of the current flowing into any one of the semiconductor switches of the above-mentioned semiconductor circuit breaker; As a result of detecting a change in the magnitude of the above current, an integrating unit that integrates the detected current magnitude according to the time elapsed from a first point in time when the current magnitude increased, when the current magnitude increases; and, A semiconductor circuit breaker characterized by including a detection control unit that transmits an overcurrent detection signal indicating the occurrence of an overcurrent to a control unit of the semiconductor circuit breaker when the current magnitude increases as a result of detection by the current detection unit, and transmits a fault current detection signal indicating the occurrence of a fault current to a control unit of the semiconductor circuit breaker according to a comparison result in which a value accumulated according to the time elapsed since the first point in time according to the integration result of the integration unit is compared with a preset threshold value.
In Paragraph 11, The above limited gate voltage is, It is a voltage lower than the normal gate voltage output by the above gate driver in a normal operating state, and The above plurality of semiconductor switches are, A semiconductor circuit breaker characterized by limiting the maximum amount of outputtable current as the above gate voltage is limited.
In Clause 11, the control unit is, A semiconductor circuit breaker characterized by controlling the plurality of gate drivers to restore the limited gate voltage when a current restoration signal indicating that the magnitude of the current flowing in from the power system has been restored is received from the current sensor while the gate voltage is limited.
In Clause 13, the control unit above is, A semiconductor circuit breaker characterized by maintaining a state in which the gate voltage is limited until the fault current detection signal or the current restoration signal is received when the overcurrent detection signal is received.
A control method for a semiconductor circuit breaker including a current sensor, A step of electrically connecting a power system and a load by driving a blocking switch and gate drivers that apply a gate voltage to a plurality of semiconductor switches equipped in the semiconductor circuit breaker; A step of detecting whether an overcurrent detection signal indicating that an overcurrent is flowing in from the power system is received from the current sensor; A step of controlling the gate drivers to apply a limited gate voltage when the above overcurrent detection signal is received; In a state of controlling the gate drivers to apply the above-mentioned limited gate voltage, a step of checking whether a fault current detection signal indicating the occurrence of a fault current or a current recovery signal indicating that the current magnitude has been restored is received from the current sensor; and, Based on the above check result, the method includes the step of controlling the cutoff switch according to the signal received from the current sensor to isolate the semiconductor circuit breaker and the load from the power system, or controlling the plurality of gate drivers to restore the limited gate voltage. The above current sensor is, Detecting a change in the magnitude of the current from the voltage of the current flowing into any one of the semiconductor switches of the above semiconductor circuit breaker, and As a result of detecting the change in the magnitude of the above current, if the magnitude of the current increases, the detected magnitude of the current is integrated according to the time elapsed from the first point in time when the magnitude of the current increased, and A control method for a semiconductor circuit breaker characterized by transmitting an overcurrent detection signal indicating the occurrence of an overcurrent to a control unit of the semiconductor circuit breaker when the magnitude of the current increases, and transmitting a fault current detection signal indicating the occurrence of a fault current to the control unit of the semiconductor circuit breaker according to a comparison result in which a value accumulated according to the time elapsed since the first point in time according to the integration result of the integration unit is compared with a preset threshold value.
In paragraph 15, The above limited gate voltage is, It is a voltage lower than the normal gate voltage output by the above gate driver in a normal operating state, and The above plurality of semiconductor switches are, A control method for a semiconductor circuit breaker characterized by limiting the maximum amount of outputtable current as the gate voltage is limited.

Description

Solid State Circuit Breaker (SSCB), Current Sensor of the SSCB, and Control Method of the SSCB and the Current Sensor The present invention relates to a semiconductor circuit breaker (SSCB) using a power semiconductor switch and a current sensor provided in the semiconductor circuit breaker. When a fault occurs in a power supply system, abnormal currents, such as overcurrents or fault currents, may flow into the load through the power system. These abnormal currents can cause damage to the load. Therefore, in the event of a power system fault, a circuit breaker may be used to disconnect the load from the power system in order to prevent the abnormal currents from flowing into the load and to block the inflow of current to the load. On the other hand, conventional mechanical circuit breakers had a problem in that it took a relatively long time of tens of milliseconds for the circuit to be interrupted, during which abnormal current flowed into the load. Therefore, nowadays, semiconductor circuit breakers (SSCBs) capable of high-speed current interruption are being used, including semiconductor switches made of power semiconductors that can conduct high currents and have high switching frequencies. These semiconductor circuit breakers have the advantage of being able to interrupt circuits at high speed because the current detection time is very short compared to breakers such as MCCBs (Molded Case Circuit Breakers). On the other hand, in the case of abnormal currents that increase instantaneously but return to a normal state within a short period of time, such as noise overcurrents or inrush currents, they do not cause damage to the load or are unlikely to cause damage, so if the circuit is interrupted due to this, the loss caused by the interruption of the circuit may actually be greater. However, as described above, in the case of semiconductor circuit breakers, the current detection time is very short, so there is a problem in that the circuit is interrupted even when currents that do not need to be interrupted or should not be interrupted, such as the noise-induced overcurrent or inrush current, occur. Furthermore, there is a problem that losses may occur if the normal operation of the load is not maintained due to the repeated unnecessary circuit interruptions. Therefore, there is currently active research being conducted on methods to enable semiconductor circuit breakers to distinguish between such temporarily occurring overcurrents (hereinafter referred to as noise overcurrents) and fault currents caused by short circuits or ground faults, and to avoid interrupting the circuit when the noise overcurrents occur. FIG. 1 is a circuit diagram illustrating the circuit structure of a semiconductor circuit breaker according to an embodiment of the present invention. FIG. 2 is a conceptual diagram illustrating an example in which bidirectional current is conducted through a semiconductor circuit breaker according to an embodiment of the present invention. FIG. 3a is a circuit diagram illustrating the current sensor circuit structure of a semiconductor circuit breaker according to an embodiment of the present invention. FIG. 3b is a block diagram illustrating the configuration of an overcurrent detection unit equipped in the current sensor shown in FIG. 3a. Figure 4 is a graph showing examples of noise overcurrent and fault current through a graph of current magnitude over time. FIG. 5 is a flowchart illustrating the operation process in which a detection control unit determines overcurrent in a current sensor of a semiconductor circuit breaker according to an embodiment of the present invention. Figure 6 is a graph showing the difference in the amount of current accumulated over time for noise-induced overcurrent and fault current. FIG. 7 is a flowchart illustrating the operation process in which a detection control unit determines whether there is an overcurrent before a certain amount of time elapses in a current sensor of a semiconductor circuit breaker according to an embodiment of the present invention. FIG. 8 is a flowchart illustrating the operation process of a semiconductor circuit breaker according to an embodiment of the present invention based on the overcurrent determination result detected by the current sensor. It should be noted that technical terms used in this specification are used merely to describe specific embodiments and are not intended to limit the invention. Additionally, singular expressions used in this specification include plural expressions unless the context clearly indicates otherwise. The suffixes "module" and "part" for components used in the following description are assigned or used interchangeably solely for the ease of drafting the specification and do not inherently possess distinct meanings or roles. In this specification, terms such as "composed" or "comprising" should not be interpreted as necessarily including all of the various components or steps described in the s