Solid state circuit breaker with negative temperature coefficient temperature data acquisition

Abstract

The utility model relates to a solid-state circuit breaker with NTC temperature data acquisition, comprising a plurality of first NTC temperature data acquisition circuits, each of which is connected with an input end and an output end of a power supply terminal and is configured to acquire a first resistance value indicating temperature data of the power supply terminal; the plurality of second NTC temperature data acquisition circuits, each of the plurality of second NTC temperature data acquisition circuits is connected with two ends of the switch, and the plurality of second NTC temperature data acquisition circuits are configured to acquire a second resistance value indicating the temperature data of the switch; a voltage follower configured to output a voltage value corresponding to the second resistance value; a voltage / frequency (V / F) conversion circuit configured to output a voltage value subjected to amplitude-frequency conversion; an isolator configured to output a digitally isolated voltage value; and the MCU is connected to the first NTC temperature data acquisition circuit and the isolator, and executes on-off of the switch based on the first resistance value and the digitally isolated voltage value.

Description

Technical Field

[0001] The utility model relates to an electrical device, in particular to a solid-state circuit breaker with negative temperature coefficient (NTC) temperature acquisition data acquisition. Background Art

[0002] Circuit breakers are widely used in power grid systems to automatically turn off in case of faults such as short circuits and leakage in the circuit that may cause personal and property safety, so that the load circuit is powered off and accidents are avoided. With the rapid development of power technology, traditional mechanical circuit breakers are gradually difficult to meet the increasingly high requirements of power systems. Solid-state circuit breakers use power electronic devices as switching elements, realizing contactless switching operations, having fast response capabilities, and being able to cut off fault currents in an extremely short time, effectively protecting the system from the influence of faults such as short circuits and leakage.

[0003] Negative temperature coefficient (NTC) refers to the phenomenon and material of a thermistor with a negative temperature coefficient, where the resistance decreases exponentially with the increase in temperature. It generally refers to semiconductor materials or components with a large negative temperature coefficient. An NTC thermistor is a negative temperature coefficient thermistor. NTC has advantages such as low cost and simple peripheral design. Therefore, NTC temperature data acquisition circuits are often set in various products on the market to achieve temperature acquisition functions. By measuring the resistance value of the NTC sensor, the corresponding temperature can be determined. Based on this characteristic, it is possible to check whether the temperature in the circuit or device is within the normal range, and then determine whether there are abnormal working states such as poor contact in the detected circuit or device, and control the working state of the circuit or device based on its working state. Summary of the Utility Model

[0004] The present utility model provides a solid-state circuit breaker with NTC temperature data acquisition, characterized in that the solid-state circuit breaker comprises: a plurality of first NTC temperature data acquisition circuits, each of the plurality of first NTC temperature data acquisition circuits being connected to the input end and the output end of a power supply terminal and configured to acquire a first resistance value indicating the temperature data of the power supply terminal; a plurality of second NTC temperature data acquisition circuits, each of the plurality of second NTC temperature data acquisition circuits being connected to both ends of a switch and configured to acquire a second resistance value indicating the temperature data of the switch; a voltage follower, the input end of the voltage follower being connected to the second NTC temperature data acquisition circuit and configured to output a voltage value corresponding to the second resistance value; a voltage / frequency V / F conversion circuit, the input end of the V / F conversion circuit being connected to the output end of the voltage follower and configured to output a voltage value after amplitude-frequency conversion; an isolator, the input end of the isolator being connected to the output end of the V / F conversion circuit and configured to output a voltage value after digital isolation; and a microcontroller MCU, connected to the first NTC temperature data acquisition circuit and the isolator and performing the on / off of the switch based on the first resistance value and the voltage value after digital isolation.

[0005] According to an embodiment of the present utility model, the power supply terminal comprises three-phase terminals A, B, C and an N terminal.

[0006] According to an embodiment of the present utility model, the switch is a metal-oxide-semiconductor field-effect transistor MOSFET.

[0007] According to an embodiment of the present utility model, the switch controls the on / off of the three-phase lines A, B, C.

[0008] According to an embodiment of the present utility model, the number of the first NTC temperature data acquisition circuits is 8, respectively acquiring the temperature data of 8 power supply terminals.

[0009] According to an embodiment of the present utility model, the number of the second NTC temperature data acquisition circuits is 6, respectively acquiring the temperature data of 6 switches.

[0010] According to an embodiment of the present utility model, the first resistance value is input to the ADC port of the MCU through I / O expansion.

[0011] According to an embodiment of the present utility model, the I / O expansion receives an address signal through the I / O port of the MCU and selects the first resistance value to be input to the ADC port of the MCU based on the received address signal.

[0012] According to an embodiment of the present utility model, the voltage value after digital isolation corresponding to the second resistance value is input to the I / O port of the MCU.

[0013] According to an embodiment of the present utility model, the voltage follower is further configured to isolate the second resistance value from the subsequent circuit

[0014] In the present utility model, the proposed solid-state circuit breaker with NTC temperature data acquisition can collect the temperature at key points for the main circuit from the A, B, C, and N terminals to the MOSFET to determine the contact state of the main circuit, and based on the judgment of whether the contact is good, execute the on / off of the switch, thereby achieving the breaking of the main circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] From the following description in conjunction with the drawings, the above and other aspects, features, and advantages of specific embodiments of the present utility model will become clearer, where:

[0016] Figure 1 is a schematic structural diagram showing the solid-state circuit breaker provided by an embodiment of the present utility model;

[0017] Figure 2 is a principle block diagram showing the solid-state circuit breaker provided by an embodiment of the present utility model;

[0018] Figure 3 is a schematic diagram of the principle of the V / F conversion circuit provided by an embodiment of the present utility model;

[0019] Figure 4 is a principle block diagram showing a system including the solid-state circuit breaker provided by an embodiment of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] Before proceeding with the following detailed description, it may be advantageous to set forth definitions of certain words and phrases used throughout this utility model. The terms "comprise" and "include" and their derivatives mean including but not limited to. The term "controller" or "control unit" refers to any device, system, or part thereof that controls at least one operation. Such a controller can be implemented in hardware, or in a combination of hardware and software and / or firmware. For example, a controller can include, for example, an application specific integrated circuit (ASIC), a general or special purpose central processing unit (CPU), a digital signal processor (DSP), and programmable logic devices such as a field programmable gate array (FPGA). A controller can be fabricated as a single printed circuit board (PCB) or distributed across several interconnected PCBs. A controller can contain other processing circuits. For example, a controller can include two processing circuits such as an FPGA and a CPU interconnected on a PCB. The functions associated with any particular controller can be centralized or distributed, whether locally or remotely. Controller. The phrase "at least one", when used in conjunction with a list of items, means that different combinations of one or more of the listed items can be used, and it may only be necessary to have one item from the list. For example, "at least one of A, B, C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, A and B and C. Also, in the description of this utility model, the terms "first", "second", etc. are only used for distinguishing descriptions and should not be construed as indicating or implying relative importance or order. In the embodiments of this disclosure, unless otherwise clearly stated, "connection" does not mean that it must be "directly connected" or "in direct contact", but only requires electrical connectivity.

[0021] Throughout this utility model, definitions of other specific words and phrases are provided. Those of ordinary skill in the art should understand that in many cases, if not most cases, such definitions apply to the prior and future use of the words and phrases so defined.

[0022] The following describes various embodiments of the principles of this utility model in conjunction with the accompanying drawings only by way of illustration and should not be construed in any way as limiting the scope of this utility model. Those skilled in the art will understand that the principles of this utility model can be implemented in any suitably arranged system or device. In some cases, the actions described in this utility model can be performed in a different order and still achieve the desired result. Additionally, the processes depicted in the drawings do not necessarily require the specific order or sequential order shown to achieve the desired result. In certain embodiments, multitasking and parallel processing may be advantageous.

[0023] The text and the drawings are provided only as examples to assist in understanding the present utility model. They should not be construed as limiting the scope of the appended claims of the present utility model in any way. Although certain embodiments and examples have been provided, it will be clear to those skilled in the art based on the content of the present utility model that the illustrated embodiments and examples can be changed without departing from the scope of the present utility model.

[0024] Figure 1 is a schematic structural diagram showing a solid-state circuit breaker provided by an embodiment of the present utility model.

[0025] Referring Figure 1 , the solid-state circuit breaker may include a plurality of first NTC temperature data acquisition circuits, a plurality of second NTC temperature data acquisition circuits, a voltage follower, a voltage / frequency V / F conversion circuit, an isolator, and a microprocessor.

[0026] Each of the plurality of first NTC temperature data acquisition circuits may be connected to the input terminal and the output terminal of the power supply terminal. Among them, the power supply terminal may include A, B, C three-phase terminals and an N terminal. A, B, C, and N respectively represent the A, B, and C phases in a three-phase four-wire transmission line, and the neutral line N. Generally, three-phase four-wire refers to a wiring method composed of three live wires and one neutral line, and a circuit powered by a three-phase power supply is called a three-phase circuit. In a three-phase system, when the three phases are balanced, there is no current passing through the neutral line (zero line).

[0027] Each of the plurality of second NTC temperature data acquisition circuits may be connected to both ends of the switch. In the embodiment of the present utility model, the switch may be a metal-oxide-semiconductor field-effect transistor MOSFET. Among them, the switch may control the on / off of the A, B, and C three-phase lines.

[0028] The input terminal of the voltage follower may be connected to the second NTC temperature data acquisition circuit.

[0029] The input terminal of the voltage / frequency V / F conversion circuit may be connected to the output terminal of the voltage follower.

[0030] The input terminal of the isolator may be connected to the output terminal of the V / F conversion circuit, and the output terminal of the isolator is connected to the microprocessor.

[0031] The microprocessor may be implemented by an MCU, and may receive the temperature data of the A, B, C, and N terminals collected through 4 I / O ports and 2 ADC ports occupied by I / O expansion, and may receive the temperature data of the MOSFET collected through 6 I / O ports.

[0032] Figure 2 is a schematic block diagram showing the principle of a solid-state circuit breaker provided by an embodiment of the present utility model.

[0033] Reference Figure 2 The solid-state circuit breaker 200 may include a power supply terminal NTC temperature data acquisition circuit 201, a switch NTC temperature data acquisition circuit 202, a voltage follower 203, a voltage / frequency V / F conversion circuit 204, an isolator 205, and an MCU 206.

[0034] The power supply terminal NTC temperature data acquisition circuit 201 may be a first NTC temperature data acquisition circuit, and may be configured to acquire a first resistance value indicating the temperature data of the power supply terminal. Among them, the power supply terminal may include A, B, C three-phase terminals and an N terminal. After insulation treatment such as additional insulating glue, the first resistance value indicating the temperature data of the input and output terminals of the A, B, C, and N terminals may be transmitted to the MCU 206.

[0035] Among them, the first resistance value of the temperature data indicating the input and output terminals of the A, B, C, and N terminals collected may be input to the ADC port of the MCU through the I / O expansion 207. The I / O expansion 207 receives an address signal through the I / O port of the MCU, and selects the first resistance value to be input to the ADC port of the MCU based on the received address signal, thereby realizing the acquisition of temperature data. By collecting the temperature data of 8 channels of A, B, C, and N terminals, it is judged whether there is a phenomenon of abnormal temperature rise of the terminals due to poor contact, so as to break the main circuit in case of abnormal heating. In the embodiment of the present invention, the main circuit may represent the circuit from the A, B, C, and N terminals to the MOSFET in the solid-state circuit breaker 200.

[0036] In addition, in the solid-state circuit breaker of the present invention, when collecting the temperature data of 8 channels of A, B, C, and N terminals, the temperature data is collected by selecting the 8 channels of A, B, C, and N terminal temperature data and occupying 4 I / O ports and 2 ADCs of the MCU, thereby saving the resources of the MCU.

[0037] The switch NTC temperature data acquisition circuit 202 may be a second NTC temperature data acquisition circuit, and may be configured to acquire a second resistance value indicating the temperature data of the switch. Among them, the switch may be a metal-oxide-semiconductor field-effect transistor MOSFET, and may control the on / off of the A, B, and C three-phase lines. After data processing including amplitude-frequency conversion, digital isolation, etc., the temperature data of the MOSFET may be converted into a digital signal meeting the insulation requirements, and then may be transmitted to 6 I / O ports of the MCU206 to realize the acquisition of temperature data.

[0038] By the switch NTC temperature data acquisition circuit, 6-channel MOSFET temperature data is collected to realize real-time detection of the MOSFET temperature, so that when overheated, the MCU receives a fault message and shuts off the circuit.

[0039] In the data processing for the second resistance value of the temperature data of the indicating switch, including amplitude-frequency conversion, digital isolation, etc., the voltage follower 203 can be used to avoid the influence of the resistance value obtained by voltage division on the subsequent circuit. In the voltage follower, the second resistance value of the temperature data of the indicating switch collected by the switch NTC temperature data acquisition circuit can be calculated according to the following Equation 1:

[0040] [Equation 1]

[0041]

[0042] Among them, R(T) is the resistance value collected by the MOSFET NTC temperature data acquisition circuit, and V(T) is the output voltage value of the voltage follower. This output voltage value corresponds to the second resistance value. Due to the property of the NTC resistance that the resistance decreases exponentially with the increase of temperature, in the temperature range of -40°C to 150°C, the value of the NTC internal resistance is in the range of 334280Ω to 181.41Ω.

[0043] The V / F conversion circuit 204 can be used to perform amplitude-frequency conversion on the voltage value corresponding to the second resistance value output by the voltage follower and output the voltage value after amplitude-frequency conversion. The specific method for calculating the frequency output can be shown according to the subsequent reference Figure 3 shown.

[0044] The isolator 205 can be used to perform digital isolation on the voltage value after amplitude-frequency conversion and output the voltage value after digital isolation.

[0045] The MCU 206 can be used to receive the collected temperature data. Based on the received first resistance value corresponding to the temperature data of the power supply terminal and the digitally isolated voltage value corresponding to the temperature data of the switch, the MCU 206 can judge the working state of the main circuit and control the on-off of the main circuit. For example, the MCU 206 can judge whether there is a phenomenon of excessive local current caused by poor contact, impurities, etc. in the main circuit based on the collected temperature data, resulting in too high temperature, and then execute the on-off of the switch to control the on-off of the main circuit.

[0046] The solid-state circuit breaker provided by the present utility model has a compact structure, and there are physical position limitations when designing for the NTC temperature data acquisition of A, B, C, and N terminals and the NTC temperature data acquisition of MOSFETs. Therefore, when collecting 8-channel A, B, C, and N terminal temperature data and 6-channel MOSFET temperature data, it is necessary to classify the acquisition positions. Due to the structural design of the solid-state circuit breaker, the acquisition loop is made as short as possible, and different insulation treatments are carried out for the two temperature data acquisition circuits of A, B, C, and N terminals and MOSFETs respectively.

[0047] Figure 3 FIG. shows the schematic diagram of the V / F conversion circuit provided by the embodiment of the present utility model.

[0048] Reference Figure 3 , in the V / F conversion circuit provided by the embodiment of the present utility model, it includes a precision silicon oscillator LTC6990 that can be used as a fixed-frequency or voltage-controlled oscillator.

[0049] Reference Figure 3 , in the V / F conversion circuit provided by the embodiment of the present utility model, the frequency output can be calculated according to the following Equation 2:

[0050] [Equation 2]

[0051]

[0052] Wherein, V(T) is the output voltage value of the voltage follower, f(T) is the frequency output of the V / F conversion circuit. Corresponding to the temperature range of -40°C to 150°C, the frequency output is in the range of 14.641 kHz to 1.37 kHz. Ndiv is the internal divider value, which is set to Ndiv = 64; the control voltage provides / absorbs current through Rvco, thereby changing the Iset current, and it is set to the first reference resistor Rvco = 62 kΩ; a single resistor Rset programs the internal main oscillator frequency of LTC6990, and it is set to the second reference resistor Rset = 200 kΩ; Vset is the voltage of the SET pin of LTC6990, which is set to Vset = 1 V; the third reference resistor Rg = 10 kΩ; the fourth reference resistor Rf = 2.21 kΩ.

[0053] Figure 4 FIG. shows the principle block diagram of the system including the solid-state circuit breaker provided by the embodiment of the present utility model.

[0054] Reference Figure 4, the system 400 includes a solid-state circuit breaker 200 and a load circuit 300. Among them, the solid-state circuit breaker 200 is connected to the load circuit 300 to turn off in the case of faults such as short circuits and leakage in the circuit that may cause personal and property safety, so that the load circuit 300 is powered off.

[0055] As described above, the solid-state circuit breaker 200 is a solid-state circuit breaker with NTC temperature data acquisition. The solid-state circuit breaker includes: a plurality of first NTC temperature data acquisition circuits, each of the plurality of first NTC temperature data acquisition circuits is connected to the input end and the output end of the power supply terminal, and is configured to acquire a first resistance value indicating the temperature data of the power supply terminal; a plurality of second NTC temperature data acquisition circuits, each of the plurality of second NTC temperature data acquisition circuits is connected to both ends of the switch, and is configured to acquire a second resistance value indicating the temperature data of the switch; a voltage follower, the input end of the voltage follower is connected to the second NTC temperature data acquisition circuit, and is configured to output a voltage value corresponding to the second resistance value; a voltage / frequency V / F conversion circuit, the input end of the V / F conversion circuit is connected to the output end of the voltage follower, and is configured to output a voltage value after amplitude-frequency conversion; an isolator, the input end of the isolator is connected to the output end of the V / F conversion circuit, and is configured to output a voltage value after digital isolation; and a microcontroller MCU, which is connected to the first NTC temperature data acquisition circuit and the isolator, and performs the on / off of the switch based on the first resistance value and the voltage value after digital isolation.

[0056] Although the present invention has been described with exemplary embodiments, various changes and modifications can be suggested to those skilled in the art. The present invention is intended to cover such changes and modifications that fall within the scope of the appended claims.

[0057] Any description in the present invention should not be construed as implying that any specific element, step or function is an essential element that must be included within the scope of the claims. The scope of the patent subject matter is defined only by the claims.

Claims

1. A solid-state circuit breaker with negative temperature coefficient (NTC) temperature data acquisition, characterized in that, The solid-state circuit breaker includes: A plurality of first NTC temperature data acquisition circuits, each of the plurality of first NTC temperature data acquisition circuits connecting the input end and the output end of the power supply terminal, and configured to acquire a first resistance value indicating the temperature data of the power supply terminal; A plurality of second NTC temperature data acquisition circuits, each of the plurality of second NTC temperature data acquisition circuits connecting both ends of the switch, and configured to acquire a second resistance value indicating the temperature data of the switch; A voltage follower, the input end of the voltage follower connecting to the second NTC temperature data acquisition circuit, and configured to output a voltage value corresponding to the second resistance value; A voltage / frequency V / F conversion circuit, the input end of the V / F conversion circuit connecting to the output end of the voltage follower, and configured to output a voltage value after amplitude-frequency conversion; An isolator, the input end of the isolator connecting to the output end of the V / F conversion circuit, and configured to output a voltage value after digital isolation; and A microcontroller MCU, connected to the first NTC temperature data acquisition circuit and the isolator, and performing the on / off of the switch based on the first resistance value and the voltage value after digital isolation.

2. The solid-state circuit breaker according to claim 1, wherein The power supply terminal includes three-phase terminals A, B, C and an N terminal.

3. The solid-state circuit breaker according to claim 1, characterized in that, The switch is a metal-oxide-semiconductor field-effect transistor MOSFET.

4. The solid-state circuit breaker according to claim 1, characterized in that, The switch controls the on / off of the three-phase lines A, B, C.

5. The solid-state circuit breaker according to claim 1, characterized in that, The number of the first NTC temperature data acquisition circuits is 8, respectively acquiring the temperature data of 8 power supply terminals.

6. The solid-state circuit breaker according to claim 1, characterized in that, The number of the second NTC temperature data acquisition circuits is 6, respectively acquiring the temperature data of 6 switches.

7. The solid-state circuit breaker according to claim 1, characterized in that, The first resistance value is input to the ADC port of the MCU through I / O expansion.

8. The solid-state circuit breaker according to claim 7, wherein The I / O expansion receives an address signal through the I / O port of the MCU, and selects the first resistance value to be input to the ADC port of the MCU based on the received address signal.

9. The solid-state circuit breaker according to claim 1, characterized in that, The voltage value after digital isolation corresponding to the second resistance value is input to the I / O port of the MCU.

10. The solid-state circuit breaker according to claim 1, characterized in that, The voltage follower is further configured to isolate the second resistance value from the backend circuit.

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