Multi-loop integrated measurement and control device and method

Abstract

This invention discloses a multi-loop integrated measurement and control device and method, comprising a circuit board located within a housing. The circuit board houses a microcontroller and multiple interface components. Each interface component includes two input ports. The two ports of each interface component are connected to the communication port of the microcontroller via isolation circuits. One port of each interface component is electrically connected together. The two output terminals of half of the interface components, after isolation circuits, are connected to the microcontroller in a forward direction, while the two output terminals of the other half of the interface components, after isolation circuits, are connected to the microcontroller in a reverse direction. This multi-loop integrated measurement and control device and method can be applied to high-current applications.

Description

Technical Field

[0001] This invention relates to a multi-loop integrated measurement and control device and method, belonging to the field of power technology. Background Technology

[0002] Currently, in industries such as electric arc furnaces, it is necessary to use measurement and control devices to measure and monitor parameters of multiple circuits of electrical equipment, thereby controlling the opening and closing of circuits through specific logic. To improve the integration of measurement and control devices, multi-circuit integrated measurement and control devices are generally used to simultaneously measure and monitor the power parameters of multiple circuits. For this purpose, the measurement and control device needs to be equipped with multiple sets of interface circuits to match the required number of circuits. During wiring, the two output terminals of the current transformer in each circuit are connected to the two input terminals of each interface group, and the wiring must correspond one-to-one; otherwise, inaccurate measurements will occur. However, in actual operation, mismatched wiring often occurs, leading to invalid monitoring data. Therefore, some companies have begun to consider merging multiple sets of interfaces, connecting one input terminal of each interface group to a busbar. This way, each time wiring is done, one of the two output terminals of the current transformer is inserted into one input terminal of the interface in sequence, and the other output terminal can be arbitrarily inserted into any port of the interface, thus simplifying the wiring operation. However, in practical applications, it has been found that although the above method simplifies the wiring, the current at the shared terminal is large due to multiple circuits sharing a single busbar, making it unsuitable for high-current applications. Therefore, corresponding improvements are urgently needed to match the high-current applications in industries such as electric arc furnaces. Summary of the Invention

[0003] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a multi-loop integrated measurement and control device and method that can be applied to high-current applications, and whose size is made more compact through an integrated structure.

[0004] The objective of this invention is achieved as follows:

[0005] A multi-loop integrated measurement and control device includes a circuit board located inside a housing. The circuit board is equipped with a microcontroller and multiple interface components. Each interface component has two input ports. The two ports of each interface component are connected to the ADC input port of the microcontroller after passing through an isolation circuit. One channel of the ports of the multiple interface components is electrically connected together. The two output terminals of half of the interface components after passing through the isolation circuit are connected to the microcontroller in the forward direction, and the two output terminals of the other half of the interface components after passing through the isolation circuit are connected to the microcontroller in the reverse direction.

[0006] Preferably, the isolation circuit includes a current transformer. The two input terminals of the current transformer are respectively connected to the two ports of the interface device. The output terminal of the current transformer is filtered by a filter circuit to output two output terminals, namely output terminal one and output terminal two. Output terminals one and output terminal two of half of the isolation circuit are directly connected to the microcontroller, and output terminals one and output terminal two of the other half of the isolation circuit are crossed and then connected to the microcontroller.

[0007] Preferably, multiple interface components are integrated into a junction box, with one port of each interface component divided into two groups and arranged at both ends of the junction box, and the other port of each interface component located in the middle of the junction box for convenient centralized connection.

[0008] A multi-loop integrated measurement and control method involves multiple circuits under test, each equipped with a primary current transformer. Half of the primary transformers are arranged in a forward configuration, and the other half in a reverse configuration. One output terminal of each primary transformer is connected to a corresponding terminal, while the other output terminal is connected to a combined terminal. This forward and reverse configuration of the transformers causes the induced currents of the multiple primary transformers to cancel each other out at the combined terminal, reducing the current value. Simultaneously, the measurement signal input from the forward-configured primary transformers is isolated and then input to a microcontroller in the forward direction; the measurement signal input from the reverse-configured primary transformers is isolated and then input to the microcontroller in the reverse direction, thus reversing the signal and ensuring measurement accuracy. In other words, for the interface of the multi-loop integrated measurement and control device, secondary current transformers are used internally for secondary isolation. For external forward-configured circuits, internal forward connection is used; for external reverse-configured circuits, internal reverse connection is used again. This ensures both current reduction in wiring and accuracy in measuring multi-functional electrical quantities.

[0009] Compared with the prior art, the beneficial effects of the present invention are:

[0010] This invention facilitates easy connection of interface components while the external reverse-connected current transformer cancels out the cascaded currents, thus reducing the total current value and making it suitable for high-current monitoring applications. Simultaneously, the internal input signal, after being reversed again, ensures that multiple signals are still connected to the microcontroller with the same phase for processing, guaranteeing monitoring accuracy and precision. Furthermore, by integrating multiple ports into a single unit and using cross-wiring to ensure signal flow, simultaneous measurement of multiple circuits under test can be achieved without adding additional electrical components. Compared to traditional single-circuit measurement, the integrated mechanism is more compact, expanding its application range. Attached Figure Description

[0011] Figure 1 This is an electrical circuit diagram of a multi-loop integrated measurement and control device according to the present invention.

[0012] Figure 2 This is a schematic diagram of the main circuit of a multi-circuit integrated measurement and control device of the present invention (the electrical markings at the end of the line are the corresponding connection terminals, and this is a schematic diagram of the whole circuit, not multiple independent circuit diagrams).

[0013] Figure 3 and Figure 4 This is a circuit diagram of a six-channel isolation circuit in a multi-loop integrated measurement and control device of the present invention.

[0014] Figure 5 and Figure 6 This is a circuit diagram of two sets of microcontrollers in a multi-loop integrated measurement and control device of the present invention. Detailed Implementation

[0015] See Figures 1-6 The present invention relates to a multi-loop integrated measurement and control device and method, comprising a circuit board located inside a housing, on which two sets of microcontrollers, model RN7302, are installed. Each set of microcontrollers receives signals from three loops, and can receive a total of six loop signals simultaneously.

[0016] The outer casing has six sets of interface components embedded in its front panel, such as... Figure 1 The interface components shown are: I1*, ICOM1; I2*, ICOM2; I3*, ICOM3; I4*, ICOM4; I5*, ICOM5; and I6*, ICOM6. All six interface components are mounted on the circuit board. The ICOM1, ICOM2, ICOM3, ICOM4, ​​ICOM5, and ICOM6 terminals of the six interface components are connected together. This connection can be achieved through copper traces on the circuit board or by physically arranging them close together and then soldering them together. The two terminals of each interface component are isolated before the signal is input to the microcontroller. The isolation circuit includes a secondary current transformer and a limiting low-pass filter circuit. The induced current generated after the primary current transformer's output passes through the secondary current transformer is filtered by the limiting low-pass filter circuit before being input to the microcontroller. Among them, the secondary current transformer is a high-precision miniature current transformer, model ZEMCT131; the limiting low-pass filter circuit is composed of high-frequency switching diodes, model 4148.

[0017] To match the convenient plug-in mating structure formed by connecting the interface component terminals together, it is necessary to reduce the current generated after the six circuits are collected through the primary current transformer. At this time, multiple adjacent primary current transformers are reverse-connected to each other, i.e. Figure 1As shown, among the primary current transformers CT1, CT2, CT3, CT4, CT5, and CT6, CT1, CT3, and CT5 are inserted into the cable of the circuit under test in the forward direction, while CT2, CT4, and CT6 are inserted into the cable of the circuit under test in the reverse direction. This results in the current phase difference of 180° between the input interface components of adjacent primary current transformers. When the six terminals of the interface components are combined together, the adjacent reverse currents will cancel each other out, thereby greatly reducing the overall current value. Therefore, it can be safely and reliably applied in high-flow environments.

[0018] Furthermore, correspondingly, since CT2, CT4, and CT6 adopt a reverse connection method, in order to ensure the accuracy of the monitored values, when the current value of the primary transformer introduced by the interface device is output by the six-channel isolation circuit, the first channel (IAN, LAP), the third channel (ICN, LCP), and the fifth channel (IB2N, LB2P) are directly input to the corresponding ports of the microcontroller. The other three channels are reverse-connected to form the second channel (IBP, LBN), the fourth channel (IA2P, LA2N), and the sixth channel (IC2P, LC2N) before being input to the corresponding ports of the microcontroller. Thus, when the data current is input through the isolation circuit, the phase of the three signals is flipped by 180° again, thereby ensuring that the phase of the six signals is the same.

[0019] Furthermore, to facilitate customer wiring, the physical structure of the six interface components was redesigned, integrating them into a single junction box. This junction box is embedded in the outer casing and contains 12 terminals, namely the 12 terminals constituting the six interface components: (I1*, ICOM1), (I2*, ICOM2), (I3*, ICOM3), (I4*, ICOM4), (I5*, ICOM5), and (I6*, ICOM6). These terminals were then rearranged, with the terminals (I1*, I2*, I3*) and (I4*, I5*, I6*) arranged in two separate groups within the junction box. The terminals (ICOM1, ICOM2, ICOM3, ICOM4, ​​ICOM5, ICOM6) are located in the middle of the junction box. That is, the six terminals (ICOM1, ICOM2, ICOM3, ICOM4, ​​ICOM5, ICOM6) are located between two sets of terminals (I1*, I2*, I3*) and (I4*, I5*, I6*), which makes it easy to connect the six terminals (ICOM1, ICOM2, ICOM3, ICOM4, ​​ICOM5, ICOM6) together by means of wires, solder, etc., which to a certain extent facilitates the flexibility of in-factory calibration and user-side wiring.

[0020] During wiring operations, operators can easily operate the system even without looking at the junction box. Simply insert one output wire of each of the six primary transformers into one of the six terminals at both ends, and then insert the other output wire into any one of the six terminals (ICOM1, ICOM2, ICOM3, ICOM4, ​​ICOM5, ICOM6). This greatly simplifies the wiring operation.

[0021] The following is combined with Figures 2-6 To elaborate further:

[0022] I1* and ICOM1 of interface component one are respectively connected to Ia1* and IA1 of the first isolation circuit;

[0023] Interface components I2* and ICOM2 are respectively connected to Ib1* and IB1 of the second isolation circuit;

[0024] Interface components I3* and ICOM3 are respectively connected to Ic1* and IC1 of the third isolation circuit;

[0025] Interface components I4* and ICOM4 are connected to Ia2* and IA2 of the fourth isolation circuit, respectively;

[0026] Interface components I5* and ICOM5 are connected to Ib2* and IB2 of the fifth isolation circuit, respectively;

[0027] Interface components I6* and ICOM6 are connected to Ic2* and IC2 of the sixth isolation circuit, respectively;

[0028] The first, second, third, fourth, fifth, and sixth isolation circuits have the same circuit structure, and are collectively referred to as isolation circuits below for description:

[0029] The isolation circuit includes a secondary current transformer. The input terminals of the secondary current transformer are (Ia1* and IA1), (Ib1* and IB1), (Ic1* and IC1), (Ia2* and IA2), (Ib2* and IB2), and (Ic2* and IC2), which are pins 1 and 2 of the ZEMCT131 type current transformer. Two high-frequency switching diodes are connected between the two output terminals of the secondary current transformer, and the two output terminals are grounded via RC filter circuits for filtering. Simultaneously, the two output terminals of the secondary current transformer are each connected to a microcontroller as output terminals. Specifically:

[0030] The output of pin 3 of the secondary transformer in the first isolation circuit is used as the output terminal IAP, and the output of pin 4 is used as the output terminal IAN.

[0031] The output of pin 3 of the secondary transformer in the second isolation circuit is used as the output terminal IBN, and the output of pin 4 is used as the output terminal IBP.

[0032] The output of pin 3 of the secondary transformer in the third isolation circuit is used as the output terminal ICP, and the output of pin 4 is used as the output terminal ICN.

[0033] The output of pin 3 of the secondary current transformer in the fourth isolation circuit is used as the output terminal IA2N, and the output of pin 4 is used as the output terminal IA2P.

[0034] The output of pin 3 of the secondary transformer in the fifth isolation circuit is used as the output terminal IB2P, and the output of pin 4 is used as the output terminal IB2N.

[0035] The output of pin 3 of the secondary transformer in the sixth isolation circuit is used as the output terminal IC2N, and the output of pin 4 is used as the output terminal IC2P.

[0036] This allows for reverse connection of adjacent output terminals, meaning half are connected in the correct orientation and the other half in the reverse orientation.

[0037] Subsequently, IAP and IAN of the first isolation circuit, IBN and IBP of the second isolation circuit, and ICP and ICN of the third isolation circuit are input to pins 1 and 2, 5 and 4, and 7 and 8 of the first microcontroller U1, respectively.

[0038] The fourth isolation circuit's IA2N and IA2P, the fifth isolation circuit's IB2P and IB2N, and the sixth isolation circuit's IC2N and IC2P are respectively input to pins 2 and 1, 4 and 5, and 8 and 7 of the second microcontroller U2.

[0039] The first microcontroller U1 and the second microcontroller U2 receive the output signal after the isolation circuit.

[0040] Additionally, it should be noted that the above-described specific implementation is merely an optimized solution of this patent, and any modifications or improvements made by those skilled in the art based on the above concept are within the scope of protection of this patent.

Claims

1. A multi-loop integrated measurement and control device, comprising a circuit board located within a housing, the circuit board having a microcontroller and multiple interface components, each interface component having two input ports, the two ports of each interface component being connected to the communication port of the microcontroller via isolation circuits, characterized in that: One port of multiple interface devices is electrically connected together. The two outputs of half of the interface devices after passing through the isolation circuit are connected to the microcontroller in the forward direction, and the two outputs of the other half of the interface devices after passing through the isolation circuit are connected to the microcontroller in the reverse direction. The isolation circuit includes a current transformer. The two input terminals of the current transformer are connected to the two ports of the interface device, respectively. The output terminal of the current transformer is filtered by a filter circuit and outputs two terminals, namely output terminal one and output terminal two. Output terminals one and two of half of the isolation circuit are directly connected to the microcontroller, while output terminals one and two of the other half of the isolation circuit are crossed and connected to the microcontroller. One half of the current transformer is inserted into the cable of the circuit under test in the forward direction, and the other half is inserted into the cable of the circuit under test in the reverse direction. This makes the current phase difference of the adjacent primary current transformer inputs to the interface device 180°. When the six terminals of the interface device are combined together, the adjacent reverse currents will cancel each other out, reducing the overall current value.

2. The multi-loop integrated measurement and control device according to claim 1, characterized in that: Multiple interface components are integrated into a junction box. One port of each interface component is divided into two groups and arranged at both ends of the junction box. The other port of each interface component is located in the middle of the junction box for easy centralized connection.

3. A multi-loop integrated measurement and control method, characterized in that: In this system, half of the primary transformers in the circuit under test are mounted in a forward configuration, and the other half in a reverse configuration. One output terminal of each primary transformer is connected to its corresponding terminal, and the other output terminal is connected to a combined terminal. This two-group configuration of the transformers allows the induced currents of the multiple primary transformers to cancel each other out at the combined terminal, reducing the current value. Simultaneously, the measurement signal input from the forward-mounted primary transformers is sent to the microcontroller in a forward configuration after passing through an isolation circuit, while the measurement signal input from the reverse-mounted primary transformers is sent to the microcontroller in a cross-reverse configuration after passing through an isolation circuit. This reversal of the signal ensures measurement accuracy.

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