Voltage detection multiplexing circuit and application

Abstract

The invention discloses a voltage detection multiplexing circuit and application, relates to the technical field of voltage detection multiplexing, and is applied to door lock detection, zero-cross detection and voltage detection. The voltage detection multiplexing circuit comprises a strong current input end, a rectification unit, a divider resistance network and an AD sampling port of the MCU chip. Through the simplified circuit architecture design, the number of required electronic elements is greatly reduced, the overall cost is reduced, and the stability and reliability of the system are improved; through a multifunctional multiplexing circuit, three functions of zero-cross detection, door lock state monitoring and voltage monitoring are ingeniously integrated. By adopting the single circuit structure, the function which can be realized by a plurality of independent circuits traditionally is effectively simplified, so that the circuit complexity and potential fault points are remarkably reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of voltage detection multiplexing, and in particular to a voltage detection multiplexing circuit and application thereof. Background Art

[0002] In existing electronic control systems, zero-crossing detection, door lock detection, and voltage detection are common functional requirements. For example, in a washing machine control system, zero-crossing detection is used to control the start and stop of the motor, door lock detection is used to ensure that the door lock is closed before starting, and voltage detection is used to monitor whether the grid voltage is normal.

[0003] In traditional solutions, these functions are usually implemented by independent detection circuits, which leads to complex circuits, a large number of electronic components, high costs, and increased system size and power consumption. Summary of the invention

[0004] In order to overcome the above-mentioned technical problems, the purpose of the present invention is to provide a voltage detection multiplexing circuit and application, which is used to solve the problem that the existing zero-crossing detection, door lock detection and voltage detection functions proposed in the above-mentioned background technology are realized by multiple independent detection circuits, resulting in complex circuits, a large number of electronic components and high costs.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A voltage detection multiplexing circuit is applied to door lock detection, zero-crossing detection and voltage detection; the voltage detection multiplexing circuit comprises a strong power input terminal, a rectifier unit, a voltage-dividing resistor network and an AD sampling port of an MCU chip; wherein the strong power input terminal is used to receive a strong power input signal; the rectifier unit is connected to the strong power input terminal and is used to rectify the input signal; the voltage-dividing resistor network is connected to the output terminal of the rectifier unit and is used to divide the signal after half-wave rectification; the AD sampling port of the MCU chip is connected to the voltage-dividing resistor network and is used to sample the voltage value after voltage division.

[0007] Preferably, the voltage-dividing resistor network includes a plurality of series-connected resistors, wherein one resistor is connected to an AD sampling port of the MCU chip.

[0008] Preferably, a voltage clamping unit is further included, wherein the voltage clamping unit is connected to the voltage-dividing resistor network and is used for clamping the voltage.

[0009] Preferably, the voltage clamping unit comprises a voltage stabilizing diode; the cathode of the voltage stabilizing diode is connected to the voltage dividing resistor network, and the anode is grounded.

[0010] Preferably, the voltage clamping unit includes two ordinary diodes; the positive electrode of one ordinary diode is connected to the power supply, and the negative electrode is connected to the voltage-dividing resistor network; the positive electrode of the other ordinary diode is connected to the voltage-dividing resistor network, and the negative electrode is grounded.

[0011] Preferably, it also includes a resistor 2, and the voltage-dividing resistor network is connected to the AD sampling port of the MCU chip through the resistor 2.

[0012] Preferably, a capacitor is also included, wherein the positive electrode or negative electrode of the capacitor is connected between the resistor 2 and the AD sampling port of the MCU chip, and correspondingly, the negative electrode or positive electrode of the capacitor is grounded.

[0013] Preferably, the rectification unit comprises a full-wave rectification unit, and the full-wave rectification unit is connected to the high-voltage input terminal via a rectification bridge.

[0014] Preferably, the rectification unit comprises a half-wave rectification unit, and the half-wave rectification unit is connected to the high-voltage input terminal via a diode.

[0015] Preferably, the half-wave rectifier unit includes an ordinary diode; the positive pole or negative pole of the ordinary diode is connected to the strong power input terminal, and correspondingly, the negative pole or positive pole of the ordinary diode is connected to the voltage-dividing resistor network.

[0016] Preferably, the rectifier unit comprises an operational amplifier biased full-wave circuit, and the operational amplifier biased full-wave circuit is connected to the high-voltage input terminal.

[0017] The application of voltage detection multiplexing circuit is applied to the abnormal voltage detection of power grid.

[0018] Beneficial effects of the present invention:

[0019] 1. The present invention not only greatly reduces the number of electronic components required and the overall cost through a streamlined circuit architecture design, but also improves the stability and reliability of the system; through a multi-functional multiplexing circuit, it cleverly integrates the three functions of zero-crossing detection, door lock status monitoring, and voltage monitoring into one. The use of this single circuit structure effectively simplifies the functions that traditionally require multiple independent circuits to achieve, thereby significantly reducing circuit complexity and potential failure points.

[0020] 2. By using two ordinary diodes instead of the Zener diode to build a clamping circuit, this design can effectively limit the voltage within a safe range, thereby protecting the chip interface of the MCU chip from overvoltage damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below in conjunction with the accompanying drawings.

[0022] Figure 1It is a schematic diagram of a zero-crossing detection circuit in the prior art;

[0023] Figure 2 It is a schematic diagram of a door lock detection circuit in the prior art;

[0024] Figure 3 It is a schematic diagram of zero-crossing detection and door lock detection in the prior art;

[0025] Figure 4 It is a schematic diagram of a voltage detection multiplexing circuit of the present invention;

[0026] Figure 5 It is a schematic diagram of the application of the voltage detection multiplexing circuit of the present invention in a washing machine control system;

[0027] Figure 6 This is the schematic diagram of the circuit connection status of the MCU chip port when the door lock is closed;

[0028] Figure 7 This is the signal waveform of the MCU chip port when the door lock is not closed;

[0029] Figure 8 It is a schematic diagram of a clamping circuit in which the voltage-stabilizing diode in the present invention is replaced by a common diode;

[0030] Fig. 9 It is a schematic diagram of the full-wave rectifier unit circuit of the present invention;

[0031] Fig.10 It is a schematic diagram of the operational amplifier bias full-wave circuit of the present invention.

[0032] In the figure: 1. Rectifier unit; 2. Voltage-dividing resistor network; 3. Voltage clamping unit; L1 / N1-high power input terminal; D1, D7, D9-ordinary diodes; R1, R2, R3, R4, R6-resistor one; R5-resistor two; D2-voltage-stabilizing diode; C11, C14-capacitors. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] like Figure 1-Figure 10As shown, a voltage detection multiplexing circuit is applied to door lock detection, zero crossing detection and voltage detection; the voltage detection multiplexing circuit includes a strong power input terminal L1 / N1, a rectifier unit 1, a voltage divider resistor network 2 and an AD sampling port of an MCU chip (microcontroller unit); wherein the strong power input terminal L1 / N1 is used to receive a strong power input signal, such as a 220V AC power supply; the rectifier unit 1 is connected to the strong power input terminal L1 / N1 (wherein L1 represents the live wire and N1 represents the neutral wire), and is used to rectify the input signal; the voltage divider resistor network 2 is connected to the output end of the rectifier unit 1, and is used to divide the signal after half-wave rectification; the AD sampling port of the MCU chip is connected to the voltage divider resistor network 2, and is used to sample the voltage value after voltage division, and realizes zero crossing detection, door lock detection and voltage detection functions through an algorithm.

[0035] It is understandable that the rectifier unit can be selected from one of a full-wave rectifier unit, a half-wave rectifier unit or an op amp biased full-wave circuit; the full-wave rectifier unit, the half-wave rectifier unit or the op amp biased full-wave circuit is connected to the strong power input terminal L1 / N1 and is used to rectify the input signal; wherein the full-wave rectifier unit includes a rectifier bridge (such as Fig. 9 As shown); the op amp bias full-wave circuit converts the input bipolar AC signal into a unipolar signal to achieve full-wave rectification, and the op amp bias full-wave circuit can be built into the MCU chip, as shown Fig.10 The dotted line part can be built into the MCU chip; the half-wave rectifier unit includes a common diode D1 (such as Figure 4 As shown); the positive electrode or negative electrode of the common diode D1 is connected to the strong power input terminal L1 / N1, and correspondingly, the negative electrode or positive electrode of the common diode D1 is connected to the voltage divider resistor network 2.

[0036] It should be noted that the common diode D1 is used to perform half-wave rectification on the input AC signal and output a pulsating half-wave signal; when the positive electrode of the common diode D1 is connected to the strong power input terminal L1 / N1 and the negative electrode is connected to the voltage divider resistor network 2, the output pulsating half-wave signal is as follows: Figure 3 As shown; half-wave rectification converts the AC signal into a unidirectional pulsating DC signal, which is convenient for subsequent voltage detection and processing. This signal is more suitable for sampling through the voltage-dividing resistor network 2, and can avoid the negative voltage of the negative half-cycle from causing damage to the subsequent circuit (such as the AD sampling port of the MCU chip); when the cathode of the ordinary diode D1 is connected to the strong power input terminal L1 / N1 and the positive electrode is connected to the voltage-dividing resistor network 2, a pulsating half-wave signal can also be output, thereby converting the AC signal into a unidirectional pulsating DC signal, which is convenient for the voltage-dividing resistor network 2 to perform sampling, and can avoid the positive voltage of the positive half-cycle from causing damage to the subsequent circuit (such as the AD sampling port of the MCU chip).

[0037] It should be noted that the voltage detection multiplexing technology realizes the multiplexing of at least two of the three functions of zero-crossing detection, door lock detection and voltage detection; it has the advantages of simple circuit structure, few electronic components, low cost and high reliability, and is particularly suitable for washing machine control systems or other systems that require multiple detection functions. It not only simplifies circuit design and reduces costs, but also improves the integration and reliability of the system, and has broad application prospects.

[0038] When the voltage detection multiplexing circuit is suitable for the washing machine control system, the detection circuit is placed at the rear end of the washing machine door lock detection line, such as Figure 5 As shown in the figure, L1 / N1 is the door lock detection line output, and L / N (where L represents the live wire and N represents the neutral wire) is the AC input. When the door lock is closed, the chip reads the voltage-divided signal after half-wave rectification, and quickly samples the voltage value through AD to realize zero-crossing detection, door lock detection, and voltage detection functions.

[0039] like Figure 4 As shown, the voltage-divider resistor network 2 includes a plurality of series resistors (i.e., resistor R1, resistor R2, resistor R3, resistor R4 and resistor R6); one of the resistors is connected to the AD sampling port of the MCU chip, and is used to divide the signal after half-wave rectification, and output a stable voltage-divided signal to the AD sampling port of the MCU chip.

[0040] like Figure 4 As shown, the voltage detection multiplexing circuit also includes a voltage clamping unit, which is connected to the voltage-dividing resistor network and is used to clamp the voltage; the voltage clamping unit 3 includes a voltage-stabilizing diode D2; the cathode of the voltage-stabilizing diode D2 is connected to the voltage-dividing resistor network 2, the anode is grounded, and is used to clamp the voltage to prevent excessive voltage from damaging the MCU chip port.

[0041] It should be noted that, in order to realize the detection of three functions, specifically: after the strong power input terminal L1 / N1 is half-wave rectified by the ordinary diode D1, a pulsating half-wave signal is output, and then the voltage is divided by multiple series resistors. The AD sampling port of the MCU chip judges whether zero crossing occurs and whether the door lock is closed through the voltage value on the resistor R6. The level and phase angle of the power supply voltage can be calculated according to the sampled voltage value. L1 is rectified by the ordinary diode D1, and L1 and N1 are converted into half-wave sinusoidal signals. The resistor R6 is divided by the resistor R1, the resistor R2, the resistor R3 and the resistor R4. The divided signal is output to the AD sampling port of the MCU chip, and the voltage is clamped by the voltage regulator diode D2 to prevent the AD sampling port of the MCU chip from being damaged by excessive voltage. The ratio of the output voltage of the AD sampling port to the AD reference voltage is multiplied by the set range of the AD to obtain the AD value. According to the value and the resistor voltage division relationship, the corresponding actual real-time voltage value of L1 / N1 can be obtained.

[0042] like Figure 8 As shown, the voltage clamping unit 3 includes a common diode D7 and a common diode D9, wherein the positive electrode of one common diode D9 is connected to the power supply, and the negative electrode is connected to the voltage-dividing resistor network 2; the positive electrode of the other common diode D7 is connected to the voltage-dividing resistor network 2, and the negative electrode is grounded.

[0043] It should be noted that the voltage stabilizing diode D2 can be replaced by a clamping circuit composed of a common diode D7 and a common diode D9 (such as a silicon diode). The common diode D9 is pulled up to VCC, and the common diode D7 is pulled down to GND, limiting the clamping voltage within a safe range, ensuring that the voltage at the MCU chip port does not exceed 5V, and protecting the MCU chip port;

[0044] This clamp circuit uses the forward conduction characteristics of the diode to automatically conduct when the input voltage exceeds the set safety threshold, directing the excess voltage to the ground line, ensuring that the voltage applied to the MCU chip port is always maintained at a safe level. This not only improves the safety and reliability of the circuit, but also provides a cost-effective protection solution because ordinary diodes are more economical than Zener diodes.

[0045] Preferably, it further includes a second resistor R5, and the voltage-dividing resistor network is connected to the AD sampling port of the MCU chip through the second resistor R5.

[0046] Preferably, a capacitor C11 is further included, wherein the positive electrode or negative electrode of the capacitor C11 is connected between the second resistor R5 and the AD sampling port of the MCU chip, and correspondingly, the negative electrode or positive electrode of the capacitor C11 is grounded.

[0047] like Figure 6 and Figure 7 As shown, the application of the voltage detection multiplexing circuit is applied to door lock detection; specifically, whether the door lock is closed is judged by detecting the level state of the MCU chip port; when the door lock is closed, the MCU chip port receives the voltage division signal after half-wave rectification; when the door lock is not closed, the MCU chip port continues to be at a low level.

[0048] It should be noted that when the door lock is closed, the strong power input terminal L1 / N1 outputs a half-wave rectified voltage-divided signal to the AD sampling port of the MCU chip through the door lock detection line. The MCU chip determines whether the door lock is closed by sampling the signal. If the door lock is not closed, the MCU chip port is continuously at a low level, indicating that the door lock is not closed.

[0049] like Figure 6 and Figure 7As shown, the application of the voltage detection multiplexing circuit is applied to zero-crossing detection; specifically, the voltage value after voltage division is sampled through the AD sampling port of the MCU chip. When the sampled value is near zero, it is defined as the zero-crossing moment, realizing the zero-crossing detection function.

[0050] It should be noted that, taking the AC 220VAC, 50Hz power grid as an example, the AD value is set to be read once every 100us, 100 sampling points can be read within 10ms, and the reading frequency is 10000Hz. Through zero-crossing positioning, the AC voltage waveform can be completely reconstructed, thereby realizing the zero-crossing detection function.

[0051] like Figure 6 and Figure 7 As shown, the application of the voltage detection multiplexing circuit is applied to voltage detection; specifically, the real-time value, peak value and effective value of the half-wave rectified divided voltage are calculated by continuously sampling the voltage value after voltage division, and the real-time value, effective value, peak value and phase angle of the AC voltage are obtained by combining the resistor voltage division relationship to realize the voltage detection function; the voltage detection multiplexing circuit can also be used for power grid frequency detection; specifically, the power grid frequency is determined by calculating the time interval between two zero crossing points.

[0052] like Figure 6 and Figure 7 As shown, the application of the voltage detection multiplexing circuit is applied to the abnormality detection of the grid voltage; specifically, it is to judge whether the grid voltage is abnormal by analyzing the sampling data to realize the protection of the circuit board.

[0053] It should be noted that the MCU chip continuously and quickly reads the half-wave rectified voltage value through the AD sampling port, and can obtain the real-time value of the half-wave rectified voltage divider, as well as the maximum value of the half-wave rectified voltage divider, that is, the peak value. The effective value of the half-wave rectified voltage divider can be calculated through cumulative integration, and the phase angle of the half-wave rectified voltage divider can be known through time; the real-time value, effective value, peak value, and phase angle of the AC voltage can be obtained through the resistor voltage divider relationship. The combination of these data can also determine the abnormality of the grid voltage and realize rapid protection of the circuit board. Combined with current detection technology, power and power factor can also be calculated in real time.

[0054] Specifically, the real-time value of the calculated voltage of the effective value is read as zero or close to zero as the zero-crossing point. Taking the AC 220VAC, 50Hz power grid as an example, the full wave period of 50Hz is 20ms, and the half wave period is 10ms. We set the AD value to be read once every 100us, and 100 can be read within 10ms. The reading frequency is 10000Hz. According to Shannon's law (the existing technology), it is much greater than 2 times of 50Hz, and a complete continuous voltage waveform can be obtained. Due to the symmetry of AC, a complete AC voltage waveform can be obtained by translational flipping. Through zero-crossing positioning, the zero-crossing point is defined as 0°, so 0°, 180°, 360° (0°) can be obtained. The phase angle, 100us is divided into 20ms, and the phase angle corresponding to each 100us moment can be obtained. In the half-wave 10ms period, the maximum value read every 100ms can be considered as the peak value. The time between the two zero-crossing points can be used to know the grid frequency, and the peak value can be used to know the real-time voltage of the grid, as well as the effective value.

[0055] In the description of the present invention, it should be understood that the terms "upper", "lower", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction and a specific direction structure and operation, and therefore, cannot be understood as a limitation on the present invention. In addition, "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0056] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", etc. should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A voltage detection multiplexing circuit, characterized in that: Applied to door lock detection, zero-crossing detection and voltage detection; the voltage detection multiplexing circuit includes: A strong current input terminal, used for receiving a strong current input signal; A rectifier unit, the rectifier unit is connected to the strong power input terminal and is used to rectify the input signal to obtain a rectified signal; A voltage-dividing resistor network, the voltage-dividing resistor network is connected to the rectifier unit and is used to divide the voltage of the rectified signal; An MCU chip, wherein an AD sampling port of the MCU chip is connected to the voltage-dividing resistor network and is used for sampling the voltage value after voltage division.

2. The voltage detection multiplexing circuit according to claim 1, characterized in that: The voltage-dividing resistor network includes a plurality of resistors 1 connected in series, wherein one resistor 1 is connected to an AD sampling port of the MCU chip.

3. The voltage detection multiplexing circuit according to claim 1, characterized in that: A voltage clamping unit is also included, which is connected to the voltage-dividing resistor network and is used to clamp the voltage.

4. The voltage detection multiplexing circuit according to claim 3, characterized in that: The voltage clamping unit comprises a voltage stabilizing diode; the cathode of the voltage stabilizing diode is connected to the voltage dividing resistor network, and the anode of the voltage stabilizing diode is grounded.

5. The voltage detection multiplexing circuit according to claim 3, characterized in that: The voltage clamping unit includes two common diodes, wherein the positive electrode of one common diode is connected to the power supply, and the negative electrode is connected to the voltage-dividing resistor network; the positive electrode of the other common diode is connected to the voltage-dividing resistor network, and the negative electrode is grounded.

6. The voltage detection multiplexing circuit according to claim 1, characterized in that: It also includes a resistor 2, and the voltage-dividing resistor network is connected to the AD sampling port of the MCU chip through the resistor 2.

7. The voltage detection multiplexing circuit according to claim 6, characterized in that: It also includes a capacitor, the positive electrode or negative electrode of the capacitor is connected between the resistor 2 and the AD sampling port of the MCU chip, and correspondingly, the negative electrode or positive electrode of the capacitor is grounded.

8. The voltage detection multiplexing circuit according to claim 1, characterized in that: The rectifying unit comprises a full-wave rectifying unit, and the full-wave rectifying unit is connected to the strong power input terminal through a rectifying bridge.

9. The voltage detection multiplexing circuit according to claim 1, characterized in that: The rectifying unit comprises a half-wave rectifying unit, and the half-wave rectifying unit is connected to the strong power input terminal through a diode.

10. The voltage detection multiplexing circuit according to claim 9, characterized in that: The half-wave rectification unit comprises an ordinary diode; the positive electrode or the negative electrode of the ordinary diode is connected to the strong power input terminal, and correspondingly, the negative electrode or the positive electrode of the ordinary diode is connected to the voltage-dividing resistor network.

11. The voltage detection multiplexing circuit according to claim 1, characterized in that: The rectifier unit comprises an operational amplifier bias full-wave circuit, and the operational amplifier bias full-wave circuit is connected to the strong power input terminal.

12. Application of the voltage detection multiplexing circuit according to any one of claims 1 to 8, characterized in that: Applied to grid voltage anomaly detection.

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