On-line opening and closing current monitoring system for permanent magnetic mechanism circuit breaker

Abstract

The utility model relates to the technical field of opening and closing current monitoring, in particular to an online opening and closing current monitoring system for a permanent magnetic mechanism circuit breaker, which comprises a permanent magnetic mechanism coil loop and a monitoring unit, and is characterized in that the permanent magnetic mechanism coil loop comprises a capacitor C, an IGBT (Insulated Gate Bipolar Translator) switch T, a diode D, an inductor L and a resistor R; the inductor L and the resistor R are connected in series and then are coupled with the positive electrode of the capacitor through the IGBT switch T. The capacitor C and the IGBT switch T are connected in series and then are connected with the diode D in parallel. The monitoring unit comprises a Hall current sensor, an amplifier U2 and a voltage follower U3; according to the utility model, the design is simple, the Hall effect principle is fully utilized, pulse current is output in a small voltage signal mode, the signal following performance is good, online coil current waveform monitoring can be realized by combining with a controller, the health degree of devices such as an electronic operation loop IGBT module and a capacitor can be analyzed according to the waveform, and local alarm is realized or through a built-in communication unit, the reliability is high, and the reliability is high. And waveform data can be uploaded to a remote background for display.

Description

Technical Field

[0001] This utility model relates to the field of circuit breaker opening and closing current monitoring technology, and in particular to an online circuit breaker opening and closing current monitoring system for permanent magnet circuit breakers. Background Technology

[0002] With the widespread use of permanent magnet mechanism coil circuit breakers, malfunctions and burnouts of the permanent magnet mechanism coil circuit drive modules are becoming increasingly common, highlighting the lack of an effective online monitoring method for the current in the permanent magnet drive circuit. Currently, current monitoring of the mechanism's opening and closing coils mainly relies on traditional current transformers. However, because the current is in a steady state, this method has significant errors when used for monitoring the current loop of pulse-type permanent magnet mechanism coils, and the CTs are prone to saturation, affecting accuracy. With the introduction of the State Grid's deep integration technology for primary and secondary circuits, higher requirements are placed on the energy storage of the operating mechanism and the current and voltage recording of the opening and closing circuits.

[0003] Introduction to the Hall effect:

[0004] When a current-carrying semiconductor material (usually made into a thin semiconductor wafer) is placed in a magnetic field, with the direction of the magnetic field making a 90° angle with the direction of the current (for optimal Hall effect), the charge carriers in the conductor will be deflected due to the Lorentz force, generating a voltage difference across the semiconductor wafer. Under the influence of the electric and magnetic fields, the movement of the charge carriers reaches an equilibrium state. This process is the generation of the Hall effect, and the resulting voltage is called the Hall potential, Vh.

[0005]

[0006] In the formula, I is the current passing through the Hall element; B is the magnetic flux density perpendicular to the Hall element; and Kh is the Hall material sensitivity coefficient. Kh = Rh / d × f(L / b), where Rh is the Hall coefficient; L, b, and d are the length, width, and height of the Hall element; and f(L / b) is the correction coefficient.

[0007] Therefore, we propose an online opening and closing current monitoring system for permanent magnet circuit breakers. Utility Model Content

[0008] To address the shortcomings of existing technologies, this utility model provides an online opening and closing current monitoring system for permanent magnet mechanism circuit breakers. This system solves the technical problem that "currently, the market mainly relies on traditional current transformers for monitoring the opening and closing coils of the mechanism. Because the current is in a steady state, this results in significant errors when used for monitoring the current loop of pulse-type permanent magnet mechanism coils, and the CT is prone to saturation, affecting accuracy. With the introduction of the State Grid's deep integration technology for primary and secondary circuits, higher requirements are placed on the energy storage of the operating mechanism and the current and voltage recording of the opening and closing circuits."

[0009] To achieve the above objectives, this utility model provides the following technical solution:

[0010] An online opening and closing current monitoring system for a permanent magnet mechanism circuit breaker includes a permanent magnet mechanism coil circuit and a monitoring unit.

[0011] The permanent magnet mechanism coil circuit includes a capacitor C, an IGBT switch T, a diode D, an inductor L, and a resistor R. The inductor L and the resistor R are connected in series and then coupled to the positive terminal of the capacitor via the IGBT switch T. The capacitor C and the IGBT switch T are connected in series and then connected in parallel with the diode D.

[0012] The monitoring unit includes a Hall current sensor, an amplifier U2, and a voltage follower U3. The positive terminal of the input of the amplifier U2 is coupled to the pin M of the Hall sensor via a resistor R1. The pin M of the Hall sensor is grounded via resistors R1 and R2. The negative terminal of the input of the amplifier U2 is coupled to the positive terminal of the input of the voltage follower U3 via a resistor R3. The output of the voltage follower U3 is coupled to a digital-to-analog converter U4 via a resistor R4. The signal output of the digital-to-analog converter U4 is coupled to an ADC sampler U5.

[0013] As a preferred embodiment of this invention, the Hall sensor is externally connected to a 12V DC voltage source.

[0014] As a preferred embodiment of this invention, the resistor R4 is grounded via capacitor C1.

[0015] As a preferred embodiment of this invention, both amplifiers U2 and U3 are externally connected to a 3.3V voltage source.

[0016] As a preferred embodiment of this invention, the Hall current sensor U1 is grounded via pin G.

[0017] This utility model provides an online opening and closing current monitoring system for a permanent magnet mechanism circuit breaker, which has the following advantages:

[0018] This application features a simple design that fully utilizes the Hall effect principle to output pulsed current as a small voltage signal. The signal has good tracking performance and, combined with a controller, enables online monitoring of coil current waveforms. Based on waveform analysis, it assesses the health of components such as the IGBT module and capacitors in the electronic operating circuit, enabling local alarms or, via a built-in communication unit, sending waveform data to a remote backend for display. Attached Figure Description

[0019] Figure 1 This is a system flowchart of the present invention;

[0020] Figure 2 This is a circuit diagram of the permanent magnet mechanism coil in this utility model;

[0021] Figure 3 This is the circuit diagram of the monitoring unit in this utility model. Detailed Implementation

[0022] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in 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 utility model and are not intended to limit the present utility model.

[0023] Therefore, a feature pointed out in this specification is used to describe one feature of one embodiment of the present invention, and does not imply that every embodiment of the present invention must have the described feature. Furthermore, it should be noted that this specification describes many features. Although certain features may be combined to illustrate possible system designs, these features may also be used in other combinations not explicitly stated. Therefore, unless otherwise stated, the described combinations are not intended to be limiting.

[0024] The principle and structure of this utility model will be described in detail below with reference to the accompanying drawings and embodiments:

[0025] refer to Figure 1-3 An online opening and closing current monitoring system for a permanent magnet mechanism coil circuit breaker includes a permanent magnet mechanism coil circuit and a monitoring unit.

[0026] The permanent magnet mechanism coil circuit includes a capacitor C, an IGBT switch T, a diode D, an inductor L, and a resistor R. The inductor L and the resistor R are connected in series and then coupled to the positive terminal of the capacitor via the IGBT switch T. The capacitor C and the IGBT switch T are connected in series and then connected in parallel with the diode D.

[0027] The monitoring unit includes a Hall current sensor, an amplifier U2, and a voltage follower U3. The positive terminal of the input of the amplifier U2 is coupled to the pin M of the Hall sensor via a resistor R1. The pin M of the Hall sensor is grounded via resistors R1 and R2. The negative terminal of the input of the amplifier U2 is coupled to the positive terminal of the input of the voltage follower U3 via a resistor R3. The output of the voltage follower U3 is coupled to a digital-to-analog converter U4 via a resistor R4. The signal output of the digital-to-analog converter U4 is coupled to an ADC sampler U5.

[0028] In this circuit, R1 and R2 are voltage divider resistors, U2 is a proportional operational amplifier, U3 is a voltage follower, R4 and C1 form a passive filter circuit, U4 is an analog-to-digital converter, and U5 is an AD sampling unit on the core board.

[0029] The permanent magnet mechanism coil circuit passes through the closed-loop Hall current sensor U1, which will induce a small voltage signal output according to the Hall effect. After passing through the voltage divider resistor, it goes to the amplifier U2 for signal amplification. The voltage follower U3 provides voltage follower isolation. After passing through the low-pass filter composed of R4 & C1, it is input to the analog-to-digital converter U4. Finally, it passes through the high-speed sampling U5 and is quantized to restore the coil current waveform.

[0030] The Hall sensor is connected to a 12V DC voltage source, the resistor R4 is grounded through the capacitor C1, the amplifier U2 and the voltage follower U3 are both connected to a 3.3V voltage source, the Hall current sensor U1 is grounded through pin G, C is the driving capacitor of the permanent magnet mechanism coil circuit, T is the high-speed IGBT switching device, D is the freewheeling diode, and L&R is the coil of the permanent magnet mechanism coil circuit after the abstract model. This method is used to monitor the i(t) waveform during the period from when the T switching device is turned on to when it is turned off (generally 50ms).

[0031] The permanent magnet mechanism coil circuit passes through a closed-loop Hall current sensor, which will induce a small voltage signal output according to the Hall effect. After passing through a voltage divider resistor, the signal is amplified by U2. The voltage of U3 follows and acts as an isolation device. After passing through a low-pass filter composed of R4 & C1, the signal is input to an analog-to-digital converter. Finally, it is sampled and quantized at high speed to restore the coil current waveform.

[0032] This technology is simple in design and makes full use of the Hall effect principle to output pulse current as a small voltage signal. It has good signal tracking and, combined with a controller, can realize online coil current waveform monitoring. Based on the waveform analysis, the health status of the IGBT module, capacitors and other components in the electronic operating circuit can be realized to achieve local alarm or, through the built-in communication unit, the waveform data can be sent to a remote background for display.

[0033] This technology, based on Ampere's circuital law and the Hall effect, converts the pulse current of the permanent magnet drive circuit's working time slot into a small voltage signal. After being restored through a signal conditioning circuit, a digital high-frequency sampling circuit, and a compensation circuit, it is processed by the CPU to restore the actual "RLC" abstract permanent magnet mechanism coil current waveform and generate an operation log. It has the function of "real-time waveform recording" of the drive current and can be used for alarm output and remote data transmission by the feeder terminal of the local permanent magnet mechanism.

[0034] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this utility model, and these modifications or substitutions should all be covered within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. An online opening and closing current monitoring system for a permanent magnet mechanism circuit breaker, comprising a permanent magnet mechanism coil circuit and a monitoring unit, characterized in that, The permanent magnet mechanism coil circuit includes a capacitor C, an IGBT switch T, a diode D, an inductor L, and a resistor R. The inductor L and the resistor R are connected in series and then coupled to the positive terminal of the capacitor via the IGBT switch T. The capacitor C and the IGBT switch T are connected in series and then connected in parallel with the diode D. The monitoring unit includes a Hall current sensor, an amplifier U2, and a voltage follower U3. The positive terminal of the input of the amplifier U2 is coupled to the pin M of the Hall sensor via a resistor R1. The pin M of the Hall sensor is grounded via resistors R1 and R2. The negative terminal of the input of the amplifier U2 is coupled to the positive terminal of the input of the voltage follower U3 via a resistor R3. The output of the voltage follower U3 is coupled to a digital-to-analog converter U4 via a resistor R4. The signal output of the digital-to-analog converter U4 is coupled to an ADC sampler U5.

2. The online opening and closing current monitoring system for a permanent magnet mechanism circuit breaker according to claim 1, characterized in that, The Hall sensor is connected to an external 12V DC voltage source.

3. The online opening and closing current monitoring system for a permanent magnet mechanism circuit breaker according to claim 1, characterized in that, The resistor R4 is grounded via capacitor C1.

4. The online opening and closing current monitoring system for a permanent magnet mechanism circuit breaker according to claim 1, characterized in that, Both amplifiers U2 and U3 are connected to an external 3.3V voltage source.

5. The online opening and closing current monitoring system for a permanent magnet mechanism circuit breaker according to claim 1, characterized in that, The Hall current sensor U1 is grounded via pin G.

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