Power line carrier communication zero-cross detection circuit and system and elevator
Through capacitive voltage division and filtering technology, combined with voltage biasing unit, the problem of low zero crossing detection accuracy in the prior art is solved, and higher detection accuracy and cost reduction are achieved.
Patent Information
- Application Number
- CN202420927428.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-29
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2034-04-29
AI Technical Summary
In the prior art, when the photocouple isolation method detects zero crossing, the diode and phototransistor have on-voltage problems, resulting in low detection accuracy.
A combined circuit of a capacitive voltage division unit, a filter unit and a voltage biasing unit is adopted to provide a bias voltage through capacitive voltage division and filtering to improve detection accuracy and reduce dependence on semiconductor devices.
Improves the accuracy of zero crossing detection, reduces design costs, and reduces dependence on diodes and optocouplers.
Smart Images
Figure CN222234853U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of electronic circuits, and in particular to a power line carrier communication zero-crossing detection circuit, system and elevator. Background Art
[0002] In the prior art, optocoupler isolation is often used to detect the zero-crossing point. After the alternating current is rectified by a rectifier diode, it enters the optocoupler. The optocoupler rectifies the alternating current signal into a square wave output. The square wave signal enters the elevator power line carrier microcontroller. The controller determines whether it is a zero point to control whether to send data. However, both the diode and the primary-side light-emitting diode of the optocoupler have a conduction voltage. When the forward voltage at both ends is greater than the conduction voltage, the phototransistor on the secondary side of the optocoupler can be turned on. At this time, the square wave signal obtained by the power line carrier controller is not the zero-crossing moment, whether it is the rising edge or the falling edge, resulting in a relatively low detection accuracy of the detection device. Therefore, there are still technical problems that need to be solved in the relevant technology. Utility Model Content
[0003] The purpose of this application is to solve one of the technical problems existing in the prior art to at least a certain extent.
[0004] To this end, an object of an embodiment of the present application is to provide a power line carrier communication zero-crossing detection circuit and a semiconductor device, wherein the power line carrier communication zero-crossing detection circuit can improve detection accuracy.
[0005] In order to achieve the above technical objectives, the technical solution adopted by the embodiment of the present application includes: a power line carrier communication zero-crossing detection circuit, which is used to connect to the live line and the neutral line of the power system, and the circuit includes an isolation voltage divider unit, a filter unit, a voltage bias unit and a detection unit; the live line, the neutral line and the filter unit are connected to the isolation voltage divider unit; the filter unit and the detection unit are connected to the voltage bias unit;
[0006] Among them, the voltage bias unit includes a first resistor, a second resistor, a third resistor and a fourth resistor; one end of the first resistor is connected to the detection unit as the first output end of the voltage bias unit; one end of the second resistor is connected to the detection unit as the second output end of the voltage bias unit; the other end of the first resistor, the other end of the second resistor and one end of the fourth resistor are connected to one end of the third resistor; the other end of the third resistor is connected to a power supply; the other end of the fourth resistor is grounded.
[0007] In addition, the power line carrier communication zero-crossing detection circuit according to the above embodiment of the utility model may also have the following additional technical features:
[0008] Furthermore, in an embodiment of the present application, the isolation voltage divider unit includes a first capacitor, a second capacitor, a third capacitor and a fourth capacitor; one end of the first capacitor is connected to the live wire, the other end of the first capacitor is connected to one end of the third capacitor, the other end of the third capacitor is connected to one end of the fourth capacitor, the other end of the fourth capacitor is connected to one end of the second capacitor, the other end of the second capacitor is connected to the neutral wire, the other end of the first capacitor serves as the first output end of the isolation voltage divider unit, and one end of the second capacitor serves as the second output end of the isolation voltage divider unit.
[0009] Furthermore, in the embodiment of the present application, the capacitance of the first capacitor is the same as the capacitance of the second capacitor, and the capacitance of the third capacitor is the same as the capacitance of the fourth capacitor.
[0010] Furthermore, in the embodiment of the present application, the capacitance of the first capacitor and the capacitance of the third capacitor satisfy the relationship: a≤1 / 100b, where a is the capacitance of the first capacitor, and b is the capacitance of the third capacitor.
[0011] Further, in the embodiment of the present application, the resistance value of the first resistor is equal to the resistance value of the second resistor, and the resistance value of the third resistor is equal to the resistance value of the fourth resistor.
[0012] Furthermore, in an embodiment of the present application, the filtering unit includes a fifth resistor, a sixth resistor, a fifth capacitor and a sixth capacitor; one end of the fifth resistor is connected to the first output end of the isolation voltage divider unit, the other end of the fifth resistor is connected to one end of the fifth capacitor, the other end of the fifth capacitor and one end of the sixth capacitor are both grounded, the other end of the sixth capacitor is connected to one end of the sixth resistor, and the other end of the sixth resistor is connected to the second output end of the isolation voltage divider unit.
[0013] Furthermore, in an embodiment of the present application, the isolation voltage divider unit includes a third capacitor; the impedance of the first resistor, the impedance of the fifth resistor and the impedance of the third capacitor satisfy the relationship: Za+Zb≥100Zc, where Za is the impedance of the first resistor at a frequency of 50 Hz, Zb is the impedance of the fifth resistor at a frequency of 50 Hz, and Zc is the impedance of the third capacitor at a frequency of 50 Hz.
[0014] Furthermore, in an embodiment of the present application, the detection unit includes an MCU chip or a field programmable gate array chip.
[0015] On the other hand, an embodiment of the present application further provides a detection system, including a power line carrier communication zero-crossing detection circuit as described above.
[0016] On the other hand, an embodiment of the present application further provides an elevator, comprising the detection system described above.
[0017] The advantages and benefits of the present application will be partially given in the following description, and partially become apparent from the following description, or be understood through the practice of the present application:
[0018] The present application can detect the zero point by a bias circuit composed of a first resistor, a second resistor, a third resistor and a fourth resistor. The present application does not use semiconductor devices such as diodes and optical couplers, but realizes the detection of the zero point by voltage division of a capacitor. The present application can improve the accuracy of zero point detection and reduce the cost of design. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 It is a module schematic diagram of a power line carrier communication zero-crossing detection circuit in a specific embodiment of the utility model;
[0020] Figure 2 It is a circuit structure diagram of a power line carrier communication zero-crossing detection circuit in a specific embodiment of the utility model;
[0021] Figure 3 It is a schematic diagram of a flow chart of the function realization of a power line carrier communication zero-crossing detection circuit in another specific embodiment of the utility model;
[0022] Figure 4 It is a structural schematic diagram of a power line carrier communication zero-crossing detection circuit in another specific embodiment of the utility model;
[0023] Figure 5 It is a schematic diagram of simulation results of the power line carrier communication zero-crossing detection circuit of the utility model. DETAILED DESCRIPTION
[0024] The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings to explain the principles and processes of the power line carrier communication zero-crossing detection circuit, system and elevator in the embodiments of the present invention.
[0025] Reference Figure 1 The present application provides a power line carrier communication zero-crossing detection circuit. The power line carrier communication zero-crossing detection circuit can be connected to the live line and the neutral line of the power system. The power line carrier communication zero-crossing detection circuit may include an isolation voltage division unit 10, a filter unit 20, a voltage bias unit 30 and a detection unit 40. The live line AC-L and the neutral line AC-N may be connected to the isolation voltage division unit 10. The isolation voltage division unit 10 may be connected to the filter unit 20. The filter unit 20 may be connected to the voltage bias unit 30. The bias unit 30 may be connected to the detection unit 40.
[0026] Among them, refer to Figure 2 , the voltage bias unit 30 may include a first resistor R3, a second resistor R4, a third resistor R5 and a fourth resistor R6. One end of the first resistor R3 can be connected to the detection unit 40 as a first output end of the voltage bias unit. One end of the second resistor R4 can be connected to the detection unit 40 as a second output end of the voltage bias unit 30. The other end of the first resistor R3, the other end of the second resistor R4 and one end of the fourth resistor R6 can be connected to one end of the third resistor R5. The other end of the third resistor R5 can be connected to the power supply VCC. The other end of the fourth resistor R6 is grounded. It can be understood that the specific value of VCC can be adjusted according to actual needs, and its voltage value can be 5V, 3.3V or a voltage of other values.
[0027] Further, in some feasible embodiments of the present application, referring to Figure 2 , the isolation voltage divider unit 10 may include a first capacitor C1, a second capacitor C2, a third capacitor C3 and a fourth capacitor C4. One end of the first capacitor C1 may be connected to the live wire AC-L. The other end of the first capacitor C1 may be connected to one end of the second capacitor C2. The other end of the second capacitor C2 may be connected to one end of the fourth capacitor C4. The other end of the fourth capacitor C4 may be connected to one end of the second capacitor C2. The other end of the second capacitor C2 may be connected to the neutral line AC-N. The other end of the first capacitor C1 serves as a first output end of the isolation voltage divider unit 10. One end of the second capacitor C2 serves as a second output end of the isolation voltage divider unit 10.
[0028] Further, in some feasible embodiments of the present application, referring to Figure 2 The capacitance of the first capacitor C1 may be the same as the capacitance of the second capacitor C2, and the capacitance of the third capacitor C3 may be the same as the capacitance of the fourth capacitor C4.
[0029] Further, in some feasible embodiments of the present application, referring to Figure 2 The capacitance of the first capacitor C1 and the capacitance of the third capacitor C3 may satisfy the relationship: a≤1 / 100b, where a is the capacitance of the first capacitor C1, and b is the capacitance of the third capacitor C3.
[0030] Further, in some feasible embodiments of the present application, referring to Figure 2 , the resistance value of the first resistor R3 is equal to the resistance value of the second resistor R4, and the resistance value of the third resistor R5 is equal to the resistance value of the fourth resistor R6.
[0031] Further, in some feasible embodiments of the present application, the filtering unit 20 may include a fifth resistor R1, a sixth resistor R2, a fifth capacitor C5 and a sixth capacitor C6; one end of the fifth resistor R1 can be connected to the first output end of the isolation voltage divider unit 10, the other end of the fifth resistor R1 can be connected to one end of the fifth capacitor C5, the other end of the fifth capacitor C5 and one end of the sixth capacitor C6 are both grounded, the other end of the sixth capacitor C6 can be connected to one end of the sixth resistor R2, and the other end of the sixth resistor R2 can be connected to the second output end of the isolation voltage divider unit 10.
[0032] Further, in some feasible embodiments of the present application, referring to Figure 2 , the isolation voltage divider unit 10 may include a first capacitor C1, a second capacitor C2, a third capacitor C3 and a fourth capacitor C4. One end of the first capacitor C1 may be connected to the live wire AC-L. The other end of the first capacitor C1 may be connected to one end of the second capacitor C2. The other end of the second capacitor C2 may be connected to one end of the fourth capacitor C4. The other end of the fourth capacitor C4 may be connected to one end of the second capacitor C2. The other end of the second capacitor C2 may be connected to the neutral wire AC-N. The other end of the first capacitor C1 serves as the first output end of the isolation voltage divider unit 10. One end of the second capacitor C2 serves as the second output end of the isolation voltage divider unit 10; the impedance of the first resistor R3, the impedance of the fifth resistor R1 and the impedance of the third capacitor C3 satisfy the relationship: Za+Zb≥100Zc, where Za is the impedance of the first resistor R1 at the frequency f=50Hz, Zb is the impedance of the fifth resistor R1 at the frequency f=50Hz, and Zc is the impedance of the third capacitor C3 at the frequency f=50Hz, where Zc==1 / (2π*f*C3), where C3 is the capacitance value of C3 at the frequency f=50Hz, and f is the frequency, generally 50Hz.
[0033] Further, in some feasible embodiments of the present application, the detection unit may include an MCU chip or a field programmable gate array chip, both of which can realize the collection of electrical signals and the processing of electrical signals. Similarly, the detection unit of the present application may also be other chips with electrical parameter detection functions and data processing functions. It is understandable that the MCU chip or the field programmable gate array chip or other chips all need to realize their electrical parameter detection and data processing functions through peripheral circuits, and the specific chip peripheral circuits can be adjusted according to different peripheral circuits, such as the peripheral circuits of the MCU may include a crystal oscillator circuit, a pull-up resistor circuit or a pull-down resistor circuit, etc.
[0034] The specific calculation principle of this application is explained below with reference to the accompanying drawings:
[0035] Reference Figure 3 as well as Figure 4, the AC power of the power line enters the isolation voltage divider unit through the live wire and the neutral wire, and outputs the voltage after capacitor voltage division; after the output voltage is divided, the voltage enters the filter unit for low-pass filtering to filter out high-frequency noise and output the filtered voltage; the filtered voltage enters the voltage bias unit, and the voltage bias unit provides a bias voltage of 1 / 2VCC, so that Ua and Ub fluctuate around 1 / 2VCC as the center point, and the change value is within the input range of the power line carrier controller port PA0 and PA1. The output voltages Ua and Ub of the voltage bias unit enter the power line carrier controller ports PA0 and PA1. The power line carrier microcontroller samples the voltages Ua and Ub through the PA0 and PA1 ports, performs analog-to-digital conversion, and then performs the difference operation between Ua and Ub (a differential sampling circuit is formed at this time), and calculates the result of Ua-Ub. If it is equal to 0, the AC power is in a zero state at this time, and the controller starts to send the data to be transmitted to the outside. The processing flow of the power line carrier controller is as follows: Figure 3 .
[0036] Specifically, the AC voltage of the power line is 220VAC, and the frequency f=50Hz; the capacitance of the first capacitor C1 and the second capacitor C2 are both 2.2nF; the capacitance of the third capacitor C3 and the fourth capacitor C4 are both 220nF; the resistance of the fifth resistor R1 and the sixth resistor R2 are both 3MΩ; the resistance of the first resistor R3 and the second resistor R4 are both 3MΩ; the capacitance of the fifth capacitor C5 and the sixth capacitor C6 are both 10pF; the resistance of the third resistor R5 and the fourth resistor R6 are both 10KΩ; the impedance of the first capacitor ZC1=1 / (2π*f*C1); the impedance of the third capacitor ZC3=1 / (2π*f*C3).
[0037] During the test, Figure 4 Ua-Ub≈[R3 / (R1+R3)]*[ZC3 / (ZC1+ZC3)]*V1, where V1 is Figure 5 Where is the input AC voltage of the power line, the peak value of V1 is 220√2V, and the frequency is f=50Hz. When the input AC passes through zero point, that is, when V1=0, Ua-Ub=0. The power line carrier controller samples and calculates that Ua-Ub=0, which is the zero point of AC. Figure 5 The simulation result waveform shows that when the AC voltage V1 is at zero point, Ua-Ub is synchronously at zero point.
[0038] In addition, an embodiment of the present application further provides a detection system, which may include one or more power line carrier communication zero-crossing detection circuits and other detection circuits as described in any of the above embodiments, such as a waveform detection circuit or a voltage detection circuit.
[0039] It should be noted that the contents of the above-mentioned power line carrier communication zero-crossing detection circuit embodiment are all applicable to the present test system embodiment, and the functions specifically implemented by the present test system embodiment are the same as those of the above-mentioned power line carrier communication zero-crossing detection circuit embodiment, and the beneficial effects achieved are also the same as those achieved by the above-mentioned power line carrier communication zero-crossing detection circuit embodiment.
[0040] In addition, an elevator is provided in an embodiment of the present application, and the elevator may include one or more detection systems described in any of the foregoing embodiments.
[0041] It should be noted that the contents of the above-mentioned detection system embodiment are all applicable to the present elevator embodiment. The functions specifically implemented by the present elevator embodiment are the same as those of the above-mentioned detection system embodiment, and the beneficial effects achieved are also the same as those achieved by the above-mentioned detection system embodiment.
[0042] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the term "switch" should be understood in a broad sense, for example, it can be a transformation or a conversion; for ordinary technicians in this field, the specific meaning of the above terms in the present invention can be understood according to specific circumstances.
[0043] In the description of this specification, the description of the reference term means that the specific structure or feature described in conjunction with the embodiment or example is included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.
[0044] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.
[0045] The above is a specific description of the preferred implementation of the present application, but the present application is not limited to the described embodiments. Technical personnel familiar with the field may make various equivalent modifications or substitutions without violating the spirit of the present application. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present application.
Claims
1. A power line carrier communication zero-crossing detection circuit, characterized in that: Used to connect with the live wire and the neutral wire of the power system, the circuit includes an isolation voltage divider unit, a filter unit, a voltage bias unit and a detection unit; the live wire, the neutral wire and the filter unit are connected to the isolation voltage divider unit; the filter unit and the detection unit are connected to the voltage bias unit; Among them, the voltage bias unit includes a first resistor, a second resistor, a third resistor and a fourth resistor; one end of the first resistor is connected to the detection unit as the first output end of the voltage bias unit; one end of the second resistor is connected to the detection unit as the second output end of the voltage bias unit; the other end of the first resistor, the other end of the second resistor and one end of the fourth resistor are connected to one end of the third resistor; the other end of the third resistor is connected to a power supply; the other end of the fourth resistor is grounded.
2. The power line carrier communication zero-crossing detection circuit according to claim 1, characterized in that: The isolation voltage divider unit includes a first capacitor, a second capacitor, a third capacitor and a fourth capacitor; one end of the first capacitor is connected to the live wire, the other end of the first capacitor is connected to one end of the third capacitor, the other end of the third capacitor is connected to one end of the fourth capacitor, the other end of the fourth capacitor is connected to one end of the second capacitor, the other end of the second capacitor is connected to the neutral line, the other end of the first capacitor serves as the first output end of the isolation voltage divider unit, and one end of the second capacitor serves as the second output end of the isolation voltage divider unit.
3. The power line carrier communication zero-crossing detection circuit according to claim 2, characterized in that: The capacitance of the first capacitor is the same as the capacitance of the second capacitor, and the capacitance of the third capacitor is the same as the capacitance of the fourth capacitor.
4. The power line carrier communication zero-crossing detection circuit according to claim 2, characterized in that: The capacitance of the first capacitor and the capacitance of the third capacitor satisfy the relationship: a≤1 / 100b, where a is the capacitance of the first capacitor and b is the capacitance of the third capacitor.
5. The power line carrier communication zero-crossing detection circuit according to claim 1, characterized in that: The resistance value of the first resistor is equal to the resistance value of the second resistor, and the resistance value of the third resistor is equal to the resistance value of the fourth resistor.
6. The power line carrier communication zero-crossing detection circuit according to claim 1, characterized in that: The filtering unit includes a fifth resistor, a sixth resistor, a fifth capacitor and a sixth capacitor; one end of the fifth resistor is connected to the first output end of the isolation voltage divider unit, the other end of the fifth resistor is connected to one end of the fifth capacitor, the other end of the fifth capacitor and one end of the sixth capacitor are both grounded, the other end of the sixth capacitor is connected to one end of the sixth resistor, and the other end of the sixth resistor is connected to the second output end of the isolation voltage divider unit.
7. The power line carrier communication zero-crossing detection circuit according to claim 6, characterized in that: The isolation voltage divider unit includes a third capacitor; the impedance of the first resistor, the impedance of the fifth resistor and the impedance of the third capacitor satisfy the relationship: Za+Zb≥100Zc, where Za is the impedance of the first resistor at a frequency of f=50Hz, Zb is the impedance of the fifth resistor at a frequency of f=50Hz, and Zc is the impedance of the third capacitor at a frequency of f=50Hz.
8. The power line carrier communication zero-crossing detection circuit according to claim 1, characterized in that: The detection unit includes an MCU chip or a field programmable gate array chip.
9. A detection system, characterized in that: It comprises the power line carrier communication zero-crossing detection circuit as described in any one of claims 1-8.
10. An elevator, characterized in that: Comprising the detection system as claimed in claim 9.