Switching value sampling circuit
By designing rectifying filtering and signal preprocessing circuits in power system equipment, converting the switch quantity into square wave signals, electrical isolation of multiple voltage levels is achieved, and the problems of complexity and high cost of equipment monitoring in the prior art are solved. , reduces management costs.
Patent Information
- Application Number
- CN202420247338.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-31
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2034-01-31
AI Technical Summary
The prior art is difficult to simultaneously apply to the switching quantity monitoring of power system equipment of different voltage levels, resulting in the need of a variety of optoelectronic isolation devices and boards, increasing management costs and usage complexity.
Design a switching quantity sampling circuit, including a rectifying filtering circuit and a signal preprocessing circuit, which converts the input switching quantity into a DC signal, and the signal preprocessing circuit converts it into a square wave signal with a fixed period, and the square wave signal. The duty cycle is linearly related to the voltage value of the original signal, and electrical isolation is achieved through a digital isolator, which is suitable for various voltage levels.
The switching input of different voltage levels is converted into digital square wave output. The controller can judge the voltage value, reduce management costs, and eliminate the need for a variety of optoelectronic isolation devices. It is suitable for all voltage levels that can be withstandable circuits.
Smart Images
Figure CN222147598U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of power systems, in particular to a switch quantity sampling circuit. Background Art
[0002] With the continuous development of power system automation technology, it is necessary to monitor power system equipment in real time. The switch quantities of these power system equipment include AC signals and DC signals, and the voltage values of the output switch quantities vary from 24V, 48V, 110V or 220V. For the monitoring of the switch quantities of the above-mentioned different power system equipment, it is often necessary to select appropriate optoelectronic isolation devices for electrical isolation according to the output type. Different parameter boards need to be provided for different input voltage levels, which brings inconvenience to on-site production and increases management costs.
[0003] In order to solve the above technical problems, Jiangsu Chuneng Engineering Technology Co., Ltd.'s public patent with publication number: CN116069098A proposes a DC wide-voltage input open-in acquisition circuit. By stabilizing and limiting the input of high voltage values and amplifying the acquisition signal of low voltage values, the range of applicable input voltage is broadened. However, the widened range is limited, and one circuit board cannot adapt to all voltage levels, and its use still has certain limitations. Utility Model Content
[0004] In order to overcome the shortcomings of the prior art, the purpose of the utility model is to provide a switch quantity acquisition circuit that can be simultaneously applicable to the input of DC or AC switch quantities of mainstream voltage levels, and realize switch quantity acquisition of mainstream power system equipment by one circuit, thereby reducing the management cost of on-site production and use.
[0005] To solve the above problems, the technical solution adopted by the utility model is as follows: a switch quantity sampling circuit, comprising: a rectifier and filter circuit, whose input end is connected to the switch quantity input, and is used to rectify and filter the input analog voltage signal of the switch quantity; a signal preprocessing circuit, whose input end is connected to the output end of the filter circuit, and whose output end is connected to a controller, and is used to convert the analog voltage signal after rectification and filtering into a square wave signal with a fixed period, and the duty cycle of the square wave signal is linearly related to the voltage value of the analog voltage signal of the switch quantity.
[0006] Compared with the prior art, the beneficial effect of the utility model is that the rectifier and filter circuit converts the input switch quantity into an analog signal in the form of a DC signal after rectification and filtering, and the signal preprocessing circuit converts the analog signal into a square wave signal with a fixed period, and the duty cycle of the square wave signal is linearly related to the voltage value of the analog signal before conversion. The circuit can realize the conversion of switch quantity inputs of different voltage levels into digital square waves and output them to the controller. The controller can judge whether the voltage value of the input switch quantity reaches the corresponding threshold value according to the duty cycle of the received square wave signal, thereby realizing the monitoring of the power system equipment. Electrical isolation is achieved by converting the switch quantity input into the corresponding digital signal. There is no photoelectric isolator in the circuit. The applicable voltage level is only limited by the withstand voltage range of the circuit components. It can be applied to the switch quantity acquisition of all voltage levels within the input range that the circuit can withstand. Only one acquisition circuit board is required on site, which reduces management costs.
[0007] In the above-mentioned switch quantity sampling circuit, the rectification and filtering circuit is a bridge rectifier circuit.
[0008] In the above-mentioned switch quantity sampling circuit, a varistor is connected in parallel to the input end of the rectifier and filter circuit, and the varistor is used to filter surge impact.
[0009] In the above-mentioned switch quantity sampling circuit, a filter capacitor is connected in parallel to the output end of the rectifier and filter circuit.
[0010] The above-mentioned switch quantity sampling circuit, the signal preprocessing circuit includes an operational amplifier circuit and a digital isolator, the input end of the operational amplifier circuit is connected to the output end of the rectification and filtering circuit, and is used to convert the analog voltage signal after rectification and filtering into an approximate square wave signal of the corresponding duty cycle, the input end of the digital isolator is connected to the output end of the operational amplifier circuit, and the output end of the digital isolator is connected to the controller, and the digital isolator is used to convert the approximate square wave signal into a square wave signal.
[0011] The utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 It is a principle block diagram of a switch quantity sampling circuit according to an embodiment of the utility model;
[0013] Figure 2 The schematic diagram of the light-on quantity sampling circuit of the embodiment of the utility model is shown in FIG. DETAILED DESCRIPTION
[0014] The embodiments of the present invention are described in detail below. Figure 1The embodiment of the utility model provides a switching quantity sampling circuit, including a rectifier filter circuit and a signal preprocessing circuit, wherein the input end of the rectifier filter circuit is connected to the switch quantity input of the power system equipment, and the analog voltage signal of the switch quantity is rectified and filtered, and the input AC or DC switch quantity is rectified into a DC signal. The input end of the signal preprocessing circuit is connected to the output end of the filter circuit, and the output end is connected to the controller, and the analog voltage signal after rectification and filtering is converted into a square wave signal with a fixed period, and the duty cycle of the square wave signal is linearly related to the voltage value of the analog voltage signal of the switch quantity. The above-mentioned switch quantity sampling circuit converts the analog voltage signal of the switch quantity into a square wave signal with a corresponding duty cycle, and realizes electrical isolation between the power system equipment and the controller by digitally processing the voltage value of the switch quantity. The controller can obtain the corresponding signal input voltage according to the duty cycle of the input square wave, and compare it with the set threshold value to realize monitoring of the power system equipment. Since the circuit uses digital isolation instead of optoelectronic isolation, the voltage level range of the input voltage that the circuit can receive is not limited by the parameters of the optoelectronic isolator. As long as the devices in the rectifier and filter circuits and the signal preprocessing circuit can support the input of 220V AC and DC power, the switching quantity collection of mainstream voltage levels can be realized. One circuit board can support the collection of switching quantities of all mainstream power system equipment. There is no need to prepare a variety of switch quantity collection circuit boards for power system equipment of different specifications, which reduces the management cost of on-site production use.
[0015] Reference Figure 2 In this embodiment, the rectifier filter circuit is a bridge rectifier circuit. The input end of the rectifier bridge D1 is connected to the switch input, which can support the input of AC signals and DC signals. The input end of the rectifier bridge D1 is connected in parallel with a varistor ZL to filter out the surge impact generated when the switch input is turned on. The positive and negative poles of the input end of the rectifier bridge D1 are also connected in series with resistors R1 and R2 respectively. The output end of the rectifier bridge D1 is connected in parallel with a capacitor C1 for filtering the output DC signal.
[0016] It is understandable that the signal preprocessing circuit can be composed of a Schmitt trigger, a hysteresis comparator or an operational amplifier. Figure 2In this embodiment, the signal preprocessing circuit is composed of an operational amplifier circuit and a digital isolator U2. The input end of the operational amplifier circuit is electrically connected to the output end of the rectifier bridge D1, and the output end is connected to the input end of the digital isolator U2. The analog voltage signal after rectification and filtering is converted into an approximate square wave signal with a fixed period waveform similar to a square wave, and the digital isolator U2 then converts the approximate square wave signal into a square wave signal. The application of operational amplifier circuits in square wave generation is common knowledge in this field, and the specific structure of the operational amplifier circuit is not described here. Compared with traditional photoelectric isolators, the power consumption of digital isolators is only one-tenth of that of photoelectric isolators, and the heat generation in a closed chassis is lower, which is more conducive to the stable operation of the equipment. Moreover, compared with photoelectric isolators, the aging characteristics of digital isolators are not obvious, and the stability of long-term operation is also better than that of photoelectric isolators.
[0017] It should be noted that in the description of the present invention, if there are any orientation descriptions, such as up, down, front, back, left, right, etc., the orientations or positional relationships indicated are all based on the orientations or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed or operated in a specific orientation, and cannot be understood as a limitation on the present invention.
[0018] In the description of the present utility model, "several" means one or more, "more" means two or more, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used to distinguish the technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.
[0019] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.
[0020] The above-mentioned implementation modes are only preferred implementation modes of the present invention, and cannot be used to limit the protection scope of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.
Claims
1. A switch quantity sampling circuit, characterized in that: include: A rectifier and filter circuit, the input end of which is connected to the switch quantity input, and is used to perform rectification and filtering processing on the analog voltage signal of the input switch quantity; The signal preprocessing circuit has an input end connected to the output end of the filtering circuit and an output end connected to the controller, and is used to convert the analog voltage signal after rectification and filtering into a square wave signal with a fixed period, and the duty cycle of the square wave signal is linearly related to the voltage value of the analog voltage signal of the switching quantity.
2. The switch quantity sampling circuit according to claim 1, characterized in that: The rectification and filtering circuit is a bridge rectifier circuit.
3. The switch quantity sampling circuit according to claim 1, characterized in that: A varistor is connected in parallel to the input end of the rectifier and filter circuit, and the varistor is used to filter surge impact.
4. The switch quantity sampling circuit according to claim 1, characterized in that: The output end of the rectifier and filter circuit is connected in parallel with a filter capacitor.
5. The switch quantity sampling circuit according to claim 1, characterized in that: The signal preprocessing circuit includes an operational amplifier circuit and a digital isolator. The input end of the operational amplifier circuit is connected to the output end of the rectification and filtering circuit, and is used to convert the analog voltage signal after rectification and filtering into an approximate square wave signal with a corresponding duty cycle. The input end of the digital isolator is connected to the output end of the operational amplifier circuit, and the output end of the digital isolator is connected to a controller. The digital isolator is used to convert the approximate square wave signal into a square wave signal.