Voltage composite processing type voltage detection circuit

Abstract

The utility model discloses a voltage composite processing type voltage detection circuit, which comprises a mutual inductor, a low-pass filter, an AD conversion module and a controller, the input end of the mutual inductor is used for being connected to voltage to be detected, and the output end of the mutual inductor is connected to the input end of the low-pass filter. The voltage composite processing type voltage detection circuit further comprises a first group of signal conversion modules, a second group of signal conversion modules and a controllable voltage supply module. The input end of the first signal conversion module is connected to the output end of the low-pass filter, the filtering output end is used for outputting filtered analog voltage, and the first signal conversion module is used for converting the filtered analog voltage into two differential analog signals. The voltage composite processing type voltage detection circuit solves the problem that in the prior art, a low-pass filter only outputs one path of signal to an AD conversion module, so that frequency characteristics in voltage to be detected by a controller are distorted to a certain extent.

Description

Technical Field

[0001] The utility model relates to an electric energy detection circuit, in particular to a voltage detection circuit with voltage composite processing. Background Art

[0002] In order to detect electric energy, a voltage detection circuit is designed to detect the voltage used.

[0003] In the prior art, the voltage detection circuit includes: a mutual inductor, a low-pass filter, an AD conversion module and a controller. The input end of the mutual inductor is connected to the voltage to be detected. The voltage to be detected is a relatively large alternating current. After the voltage to be detected is connected through the input end of the mutual inductor, it is connected through the first coil of the mutual inductor. A second coil beside the first coil in the mutual inductor induces a voltage, and the voltage of the second coil is output through the output end of the mutual inductor. The voltage at the second coil is relatively low. The output end of the mutual inductor is connected to the input end of the filter, the output end of the filter is connected to the input end of the AD conversion module, and the output end of the AD conversion module is connected to the input end of the controller, so as to realize voltage detection.

[0004] Although the above voltage detection circuit can realize voltage detection, the disadvantages of the voltage detection circuit still exist: during the transmission process, since the low-pass filter only outputs one signal to the AD conversion module, and the voltage to be detected has frequency characteristics, it may cause a certain distortion phenomenon in the frequency characteristics of the voltage to be detected detected by the controller. Summary of the Utility Model

[0005] The utility model aims to provide a voltage detection circuit with voltage composite processing to solve the problem that the frequency characteristics of the voltage detected by the controller are distorted to a certain extent because the low-pass filter only outputs one signal to the AD conversion module in the prior art.

[0006] To achieve the above object, the utility model adopts the following technical solutions:

[0007] The utility model discloses a voltage detection circuit with voltage composite processing, which includes: a mutual inductor, a low-pass filter, an AD conversion module and a controller. The input end of the mutual inductor is used to connect to the voltage to be detected, and the output end of the mutual inductor is connected to the input end of the low-pass filter. The voltage detection circuit with voltage composite processing further includes: a first group of signal conversion modules, a second group of signal conversion modules and a controllable voltage supply module; the input end of the first group of signal conversion modules is connected to the output end of the low-pass filter, and the filtered output end is used to output the filtered analog voltage. The first group of signal conversion modules is used to convert the filtered analog voltage into two differential analog signals. The first output end and the second output end of the first group of signal conversion modules are respectively connected to the first input end and the second input end of the AD conversion module; the voltage to be measured input end of the second group of signal conversion modules is connected to the output end of the low-pass filter, and the filtered analog voltage is a sine signal. The second group of signal conversion modules is used to convert the filtered analog voltage into a square wave signal, and the output end of the second group of signal conversion modules is connected to the third input end of the AD conversion module; the controller controls the voltage output of the controllable voltage supply module, and the output end of the controllable voltage supply module is connected to the reference voltage input end of the second group of signal conversion modules; in the AD conversion module, the first input end corresponds to the first output end, the second input end corresponds to the second output end, the third input end corresponds to the third output end, and the first output end, the second output end and the third output end of the AD conversion module are respectively connected to the first input end, the second input end and the third input end of the controller.

[0008] Preferably, the mutual inductor includes: a first step-down unit, an inductor X1 and a first amplification unit. The L end of the voltage to be detected is connected to the first input end of the inductor X1 through the first step-down unit, the second input end of the inductor X1 is connected to the N end of the voltage to be detected, and the first output end and the second output end of the inductor X1 are respectively connected to the inverting input end and the non-inverting input end of the first amplification unit.

[0009] Preferably, the first group of signal conversion modules is a single-ended to differential module.

[0010] Preferably, the first group of signal conversion modules includes: resistor R11, resistor R12, resistor R13, resistor R14, resistor R15, resistor R16, capacitor C3, and differential amplifier U3. The first end of resistor R11 is grounded, the second end of resistor R11 is connected to the first end of resistor R12, the second end of resistor R12 is connected to the first end of resistor R13, the second end of resistor R11 is linked to the non-inverting input terminal of differential amplifier U3, and the inverting output terminal of differential amplifier U3 is connected to the first end of resistor R13. The first end of resistor R14 is connected to the output terminal of the low-pass filter, the second end of resistor R14 is connected to the first end of resistor R15, the second end of resistor R15 is connected to the first end of resistor R16, the second end of resistor R14 is linked to the inverting input terminal of differential amplifier U3, and the non-inverting output terminal of differential amplifier U3 is connected to the first end of resistor R16. The second end of resistor R13 is connected to the positive electrode of capacitor C3, the negative electrode of capacitor C3 is connected to the second end of resistor R16, the second end of resistor R13 is the first output terminal of the first group of signal conversion modules, and the second end of resistor R16 is the second output terminal of the first group of signal conversion modules.

[0011] Preferably, the second group of signal conversion modules includes: a band-pass filter, a limit compensation unit, and a comparison and shaping unit. The input terminal of the band-pass filter is connected to the output terminal of the low-pass filter, the output terminal of the band-pass filter is connected to the input terminal of the limit compensation unit, the output section of the limit compensation unit is connected to the input terminal of the comparison and shaping unit, the input terminal of the comparison and shaping unit is connected to the voltage to be measured input terminal of the second group of signal conversion modules, the reference voltage terminal of the comparison and shaping unit is the reference voltage input terminal of the second group of signal conversion modules, and the output terminal of the comparison and shaping unit is the output terminal of the second group of signal conversion modules.

[0012] Preferably, the controllable voltage supply module includes: voltage-dividing resistors R21, R18, R19, R20, a first controllable switch unit, a second controllable switch unit, a third controllable switch unit, and a sliding resistor RV. One end of voltage-dividing resistor R21 is connected to DC power supply VDD, the other end of voltage-dividing resistor R21 is connected to one end of voltage-dividing resistor R18, one end of voltage-dividing resistor R19, and one end of voltage-dividing resistor R20. The other end of voltage-dividing resistor R18 is connected to the moving end and the first fixed end of sliding resistor RV through the first controllable switch unit, the other end of voltage-dividing resistor R19 is connected to the moving end and the first fixed end of sliding resistor RV through the second controllable switch unit, one end of voltage-dividing resistor R20 is connected to the moving end and the first fixed end of sliding resistor RV through the third controllable switch unit, and the first controllable switch unit, the second controllable switch unit, and the third controllable switch unit.

[0013] Preferably, the first controllable switch unit, the second controllable switch unit, and the third controllable switch unit all include: a triode Q1, the emitter of the triode Q1 is connected to the movable end of the sliding resistor RV and the first fixed end, the collector of the triode Q1 is connected to the voltage-dividing resistor R18, the voltage-dividing resistor R19, or the voltage-dividing resistor R20, and the base of the triode Q1 is connected to the first output terminal, the second output terminal, or the third output terminal of the controller.

[0014] Compared with the prior art, the present utility model has the following beneficial effects:

[0015] In this application, first, a mutual inductor is used to convert the voltage to be detected into a low-voltage analog signal that can be processed; then, a low-pass filter is used to achieve the first filtering; then, the first group of signal conversion modules and the second group of signal conversion modules are used to convert the low-voltage analog signal into three different signals to be processed; then, an AD conversion module is used to convert the three different signals to be processed into three digital signals; finally, the controller identifies the three digital signals. The controller can know the frequency and amplitude of the voltage to be detected through the three digital signals. By identifying the three different digital signals, the phenomenon of frequency distortion caused by only one signal identification can be compensated.

[0016] Other advantages, objectives, and features of the present utility model will be partially reflected by the following description, and partially will also be understood by those skilled in the art through the research and practice of the present utility model. Description of the Drawings

[0017] Figure 1 It is the circuit diagram of the mutual inductor in the voltage composite processing type voltage detection circuit.

[0018] Figure 2 It is the circuit diagram of the low-pass filter.

[0019] Figure 3 It is the circuit diagram of the first group of signal conversion modules.

[0020] Figure 4 It is the circuit diagram of the comparison shaping unit and the controllable voltage supply module.

[0021] Figure 5 It is the circuit diagram of the band-pass filter.

[0022] Figure 6 It is the circuit diagram of the limit compensation unit. Detailed Embodiment

[0023] In order to make the technical means, creative features, achieved objectives, and functions of the present utility model clearer and easier to understand, the present utility model will be further described below in conjunction with the drawings and specific embodiments:

[0024] AsFigures 1 to 6 As shown in the figure, the utility model discloses a voltage detection circuit with voltage composite processing, which includes: a mutual inductor, a low-pass filter, an AD conversion module and a controller. The input end of the mutual inductor is used to connect to the voltage to be detected, and the output end V-VIN-A of the mutual inductor is connected to the input end of the low-pass filter. The voltage detection circuit with voltage composite processing further includes: a first group of signal conversion modules, a second group of signal conversion modules and a controllable voltage supply module; the input end of the first group of signal conversion modules is connected to the output end AD-VIN-A of the low-pass filter, and the filtered output end is used to output the filtered analog voltage. The first group of signal conversion modules is used to convert the filtered analog voltage into two differential analog signals. The first output end AD-VIN-A- of the first group of signal conversion modules and the second output end AD-VIN-A+ of the first group of signal conversion modules are respectively connected to the first input end and the second input end of the AD conversion module; the input end of the voltage to be detected of the second group of signal conversion modules is connected to the output end AD-VIN-A of the low-pass filter, and the filtered analog voltage is a sine signal. The second group of signal conversion modules is used to convert the filtered analog voltage into a square wave signal, and the output end of the second group of signal conversion modules is connected to the third input end of the AD conversion module; the controller controls the voltage output of the controllable voltage supply module, and the output end of the controllable voltage supply module is connected to the reference voltage input end of the second group of signal conversion modules; in the AD conversion module, the first input end corresponds to the first output end, the second input end corresponds to the second output end, the third input end corresponds to the third output end, and the first output end, the second output end and the third output end of the AD conversion module are respectively connected to the first input end, the second input end and the third input end of the controller.

[0025] The mutual inductor includes: a first step-down unit, an inductor X1 and a first amplification unit. The L end of the voltage to be detected is connected to the first input end of the inductor X1 through the first step-down unit. The second input end of the inductor X1 is connected to the N end of the voltage to be detected. The first output end and the second output end of the inductor X1 are respectively connected to the inverting input end and the non-inverting input end of the first amplification unit. The first step-down unit realizes the step-down function, and the inductor X1 realizes the function of isolating the high-voltage end from the low-voltage end, reducing the probability of damaging the electrical components at the low-voltage end.

[0026] The first step-down unit includes: resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, inductor L1, inductor X1 and thermistor VR1. One end of resistor R1 is connected to the L terminal of the voltage to be detected, the other end of resistor R1 is connected to one end of resistor R2, the other end of resistor R2 is connected to one end of resistor R3, the other end of resistor R3 is connected to one end of resistor R4, the other end of resistor R4 is connected to resistor R5, the other end of resistor R5 is connected to one end of inductor L1, the other end of inductor L1 is connected to the first end of inductor X1, the other end of inductor wire X1 is connected to one end of thermistor VR1, and the other end of thermistor VR1 is connected to the N terminal of the voltage to be detected; The first amplification unit includes: resistor R6, amplifier U1, diode D1 and diode D2. The first output terminal and the second output terminal of inductor X1 are respectively connected to the anode and cathode of diode D1, the anode of diode D1 is connected to the cathode of diode D2, the cathode of diode D1 is connected to the anode of diode D2, the cathode of diode D2 is respectively connected to one end of resistor R6 and the inverting input terminal of amplifier U1, the anode of diode D2 is connected to the non-inverting input terminal of amplifier U1, and the other end of resistor R6 is connected to the output terminal of amplifier U1.

[0027] The first group of signal conversion modules is a single-ended to differential module. It can convert a low-voltage analog signal into two differential analog signals, and the differential analog signals can be compared with each other, thereby reducing the probability of frequency distortion.

[0028] The first group of signal conversion modules includes: resistor R11, resistor R12, resistor R13, resistor R14, resistor R15, resistor R16, capacitor C3 and differential amplifier U3. The first end of resistor R11 is grounded, the second end of resistor R11 is connected to the first end of resistor R12, the second end of resistor R12 is connected to the first end of resistor R13, the second end of resistor R11 is connected to the non-inverting input terminal of differential amplifier U3, and the inverting output terminal of differential amplifier U3 is connected to the first end of resistor R13; The first end of resistor R14 is connected to the output terminal of the low-pass filter, the second end of resistor R14 is connected to the first end of resistor R15, the second end of resistor R15 is connected to the first end of resistor R16, the second end of resistor R14 is connected to the inverting input terminal of differential amplifier U3, and the non-inverting output terminal of differential amplifier U3 is connected to the first end of resistor R16; The second end of resistor R13 is connected to the positive electrode of capacitor C3, the negative electrode of capacitor C3 is connected to the second end of resistor R16, the second end of resistor R13 is the first output terminal of the first group of signal conversion modules, and the second end of resistor R16 is the second output terminal of the first group of signal conversion modules.

[0029] The low-pass filter mainly uses the TL071 type chip U2.

[0030] The second group of signal conversion modules includes: a band-pass filter, a limit compensation unit, and a comparison and shaping unit. The input end of the band-pass filter is connected to the output end AD-VIN-A of the low-pass filter. The output end of the band-pass filter is connected to the input end of the limit compensation unit. The output section of the limit compensation unit is connected to the input end of the comparison and shaping unit. The input end of the comparison and shaping unit is connected to the voltage to be measured input end of the second group of signal conversion modules. The reference voltage end of the comparison and shaping unit is the reference voltage input end of the second group of signal conversion modules. The output end of the comparison and shaping unit is the output end of the second group of signal conversion modules.

[0031] The band-pass filter mainly uses the LM358 model chip U5. The limit compensation unit mainly uses the TP1271 model chip U6.

[0032] The controllable voltage supply module includes: voltage-dividing resistors R21, R18, R19, R20, a first controllable switch unit, a second controllable switch unit, a third controllable switch unit, and a sliding resistor RV. One end of the voltage-dividing resistor R21 is connected to the DC power supply VDD. The other end of the voltage-dividing resistor R21 is connected to one end of the voltage-dividing resistor R18, one end of the voltage-dividing resistor R19, and one end of the voltage-dividing resistor R20. The other end of the voltage-dividing resistor R18 is connected to the moving end and the first fixed end of the sliding resistor RV through the first controllable switch unit. The other end of the voltage-dividing resistor R19 is connected to the moving end and the first fixed end of the sliding resistor RV through the second controllable switch unit. One end of the voltage-dividing resistor R20 is connected to the moving end and the first fixed end of the sliding resistor RV through the third controllable switch unit, the first controllable switch unit, and the second controllable switch unit. When two differential signals are detected by the first group of signal conversion modules, the low-voltage analog signal output by the low-pass filter can be known. Thus, the on / off of the first controllable switch unit, the second controllable switch unit, and the third controllable switch unit can be controlled to initially control the resistance access of the voltage-dividing resistors R18, R19, and R20, so as to initially adjust the voltage division formed by the voltage-dividing resistors R18, R19, and R20. Initially adjusting the parallel resistance value composed of the voltage-dividing resistors R18, R19, and R20 is also the rough adjustment of the parallel resistance value. Then, the resistance value of the sliding resistor RV is adjusted to avoid the resistance value being affected too much by the temperature drift due to a large span of adjusting the sliding resistor RV at one time. Thus, the voltage at the connection point of the voltage-dividing resistor R21 and the voltage-dividing resistor R18 is increased, which is also to adjust the reference voltage value accessed by the comparison and shaping unit, so as to control the width of the square wave signal output by the comparison and shaping unit to be at a specified value.

[0033] The first controllable switch unit, the second controllable switch unit, and the third controllable switch unit all include: a triode Q1. The emitter of the triode Q1 is connected to the movable end of the sliding resistor RV and the first fixed end. The collector of the triode Q1 is connected to the voltage-dividing resistor R18, the voltage-dividing resistor R19, or the voltage-dividing resistor R20. The base of the triode Q1 is connected to the first output terminal, the second output terminal, or the third output terminal of the controller.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. Voltage composite processing type voltage detection circuit, comprising: A current transformer, a low-pass filter, an AD conversion module, and a controller. The input end of the current transformer is used to connect to the voltage to be detected, and the output end of the current transformer is connected to the input end of the low-pass filter. It is characterized in that it further includes: a first group of signal conversion modules, a second group of signal conversion modules, and a controllable voltage supply module; The input end of the first group of signal conversion modules is connected to the output end of the low-pass filter. The filtered output end is used to output the filtered analog voltage. The first group of signal conversion modules is used to convert the filtered analog voltage into two differential analog signals. The first output end and the second output end of the first group of signal conversion modules are respectively connected to the first input end and the second input end of the AD conversion module; The input end of the voltage to be measured of the second group of signal conversion modules is connected to the output end of the low-pass filter. The filtered analog voltage is a sine signal. The second group of signal conversion modules is used to convert the filtered analog voltage into a square wave signal. The output end of the second group of signal conversion modules is connected to the third input end of the AD conversion module; The controller controls the voltage output of the controllable voltage supply module. The output end of the controllable voltage supply module is connected to the reference voltage input end of the second group of signal conversion modules; In the AD conversion module, the first input end corresponds to the first output end, the second input end corresponds to the second output end, the third input end corresponds to the third output end. The first output end, the second output end, and the third output end of the AD conversion module are respectively connected to the first input end, the second input end, and the third input end of the controller.

2. The voltage composite processing type voltage detection circuit according to claim 1, wherein, The current transformer includes: a first step-down unit, an inductor X1, and a first amplification unit. The L end of the voltage to be detected is connected to the first input end of the inductor X1 through the first step-down unit. The second input end of the inductor X1 is connected to the N end of the voltage to be detected. The first output end and the second output end of the inductor X1 are respectively connected to the inverting input end and the non-inverting input end of the first amplification unit.

3. The voltage composite processing type voltage detection circuit according to claim 1, wherein The first group of signal conversion modules is a single-ended to differential module.

4. The voltage composite processing type voltage detection circuit according to claim 3, wherein The first group of signal conversion modules includes: a resistor R11, a resistor R12, a resistor R13, a resistor R14, a resistor R1, a resistor R16, a capacitor C3, and a differential amplifier U3. The first end of the resistor R11 is grounded. The second end of the resistor R11 is connected to the first end of the resistor R12. The second end of the resistor R12 is connected to the first end of the resistor R13. The second end of the resistor R11 is connected to the non-inverting input end of the differential amplifier U3. The inverting output end of the differential amplifier U3 is connected to the first end of the resistor R13; The first end of the resistor R14 is connected to the output end of the low-pass filter. The second end of the resistor R14 is connected to the first end of the resistor R15. The second end of the resistor R15 is connected to the first end of the resistor R16. The second end of the resistor R14 is connected to the inverting input end of the differential amplifier U3. The non-inverting output end of the differential amplifier U3 is connected to the first end of the resistor R16; The second end of the resistor R13 is connected to the positive electrode of the capacitor C3. The negative electrode of the capacitor C3 is connected to the second end of the resistor R16. The second end of the resistor R13 is the first output end of the first group of signal conversion modules. The second end of the resistor R16 is the second output end of the first group of signal conversion modules.

5. The voltage composite processing type voltage detection circuit according to claim 3, characterized in that The second group of signal conversion modules includes: a band-pass filter, a limit compensation unit, and a comparison and shaping unit. The input end of the band-pass filter is connected to the output end of the low-pass filter. The output end of the band-pass filter is connected to the input end of the limit compensation unit. The output section of the limit compensation unit is connected to the input end of the comparison and shaping unit. The input end of the comparison and shaping unit is connected to the voltage to be measured input end of the second group of signal conversion modules. The reference voltage end of the comparison and shaping unit is the reference voltage input end of the second group of signal conversion modules. The output end of the comparison and shaping unit is the output end of the second group of signal conversion modules.

6. The voltage composite processing type voltage detection circuit according to claim 5, wherein The controllable voltage supply module includes: a voltage-dividing resistor R21, a voltage-dividing resistor R18, a voltage-dividing resistor R19, a voltage-dividing resistor R20, a first controllable switch unit, a second controllable switch unit, a third controllable switch unit, and a sliding resistor RV. One end of the voltage-dividing resistor R21 is connected to the DC power supply VDD. The other end of the voltage-dividing resistor R21 is connected to one end of the voltage-dividing resistor R18, one end of the voltage-dividing resistor R19, and one end of the voltage-dividing resistor R20. The other end of the voltage-dividing resistor R18 is connected to the moving end and the first fixed end of the sliding resistor RV through the first controllable switch unit. The other end of the voltage-dividing resistor R19 is connected to the moving end and the first fixed end of the sliding resistor RV through the second controllable switch unit. One end of the voltage-dividing resistor R20 is connected to the moving end and the first fixed end of the sliding resistor RV through the third controllable switch unit, the first controllable switch unit, the second controllable switch unit, and the third controllable switch unit.

7. The voltage composite processing type voltage detection circuit according to claim 6, characterized in that, The first controllable switch unit, the second controllable switch unit, and the third controllable switch unit all include: a triode Q1. The emitter of the triode Q1 is connected to the moving end and the first fixed end of the sliding resistor RV. The collector of the triode Q1 is connected to the voltage-dividing resistor R18, the voltage-dividing resistor R19, or the voltage-dividing resistor R20. The base of the triode Q1 is connected to the first output end, the second output end, or the third output end of the controller.

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