CN216771835U - Three-phase voltage sampling conditioning circuit based on resistance voltage division method - Google Patents
Three-phase voltage sampling conditioning circuit based on resistance voltage division method Download PDFInfo
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- CN216771835U CN216771835U CN202122928430.8U CN202122928430U CN216771835U CN 216771835 U CN216771835 U CN 216771835U CN 202122928430 U CN202122928430 U CN 202122928430U CN 216771835 U CN216771835 U CN 216771835U
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Abstract
The utility model relates to a three-phase voltage sampling conditioning circuit based on a resistance voltage division method, which is simple in circuit structure and comprises three-phase voltage sampling conditioning units and a neutral line voltage division unit, wherein each three-phase voltage sampling conditioning unit comprises a resistance voltage division unit, the input end of the resistance voltage division unit is used for being connected with any phase line of a three-phase alternating current circuit, the output end of the resistance voltage division unit is connected with the input end of a voltage conditioning unit, the output end of the voltage conditioning unit is connected with the input end of a limiting circuit, and the output end of the limiting circuit is used for being connected with an analog-to-digital converter (ADC); the voltage conditioning unit comprises a first operational amplifier, an inverting input end of the first operational amplifier is connected with an output end of the resistance voltage dividing unit through a first input resistor, an inverting input end of the first operational amplifier is connected with an output end of the first operational amplifier through a feedback resistor, and in-phase input ends of the first operational amplifiers of the three-phase voltage sampling conditioning units are connected with the neutral voltage dividing unit through second input resistors.
Description
Technical Field
The utility model relates to the technical field of signal sampling, in particular to a three-phase voltage sampling conditioning circuit based on a resistance voltage division method.
Background
The pollution of electric energy is becoming more and more serious due to the massive use of modern power electronic equipment and nonlinear loads, and the governance of the electric energy quality becomes a topic which is increasingly concerned by the power sector and users thereof, so that the significance of the research and development of equipment for governing the electric energy quality is great. In order to obtain the quality of electric energy, the voltage and current information of the electric energy needs to be acquired, but the voltage of a power grid in a power distribution network is usually 380V of three phases of a mains supply, the voltage ratio is high, the electric grid cannot directly enter an analog-digital converter module for processing, and sampling and conditioning are needed.
For a common three-phase four-wire system power grid framework of a power grid in China, a transformer is mostly adopted for isolation sampling of the power grid voltage in the traditional voltage sampling, although the isolation protection effect can be achieved, the transformer is high in cost and large in structure, and the volume and the use cost of an instrument for controlling the power quality are increased.
Disclosure of Invention
The utility model aims to provide a three-phase voltage sampling conditioning circuit based on a resistance voltage division method, which has the advantages of simple circuit structure and low cost, is used for sampling conditioning at the rear side of an electric energy quality control instrument connected with a phase line, can realize the lightning protection and overcurrent protection of a power grid, can perform operations such as amplification, filtering, voltage lifting and the like on a collected voltage signal, and converts the collected voltage signal into a standard analog signal suitable for being recognized by an analog-to-digital converter, thereby realizing the sampling conditioning of three-phase voltage.
The purpose of the utility model is realized by adopting the following scheme: a three-phase voltage sampling and conditioning circuit based on a resistance voltage division method comprises three-phase voltage sampling and conditioning units and a neutral line voltage division unit, wherein each three-phase voltage sampling and conditioning unit comprises a resistance voltage division unit, the input end of each resistance voltage division unit is used for being connected with any phase line of a three-phase alternating current circuit through a protection circuit of an electric energy quality treatment instrument, the output end of each resistance voltage division unit is connected with the input end of a voltage conditioning unit, the output end of each voltage conditioning unit is connected with the input end of a limiting circuit, the output end of each limiting circuit is used for being connected with an ADC (analog to digital converter), each voltage conditioning unit of the three-phase voltage sampling and conditioning units is connected to the output end of the neutral line voltage division unit in parallel, and the input end of the neutral line voltage division unit is used for being connected with a neutral line;
the voltage conditioning unit includes that first fortune is put, the inverting input that first fortune was put is connected with the output of resistance voltage divider unit through first input resistance, the inverting input that first fortune was put is connected with the output that first fortune was put through a feedback resistance, the homophase input that each first fortune that three-phase voltage sampling conditioning unit was put all is connected with the output of neutral line voltage divider unit through second input resistance, a ground resistance that connects in parallel between the homophase input that second input resistance and first fortune were put, an amplitude limiting unit that connects in parallel between the inverting input that first fortune was put and the homophase input for prevent that first fortune from putting by high voltage breakdown.
Preferably, a filter circuit unit is arranged between the voltage conditioning unit and the amplitude limiting circuit and used for filtering.
Preferably, the filter circuit unit is a second-order active low-pass filter circuit for filtering out high-frequency voltage components.
Preferably, the filter circuit unit comprises a second operational amplifier, a first resistor and a second resistor are sequentially connected in series between a non-inverting input end of the second operational amplifier and an output end of the voltage conditioning unit, a first filter capacitor is connected in parallel between the first resistor and the second resistor, and the first filter capacitor is grounded;
the inverting input end of the second operational amplifier is connected with the output end of the second operational amplifier, and the output end of the second operational amplifier is connected with the input end of the amplitude limiting circuit;
and a second filter capacitor is connected in parallel between the non-inverting input end and the inverting input end of the second operational amplifier.
Preferably, a voltage raising resistor is connected in parallel between the first resistor and the second resistor, and is used for raising the input voltage of the second operational amplifier.
Preferably, the resistance voltage dividing unit/neutral line voltage dividing unit includes a first adjustable resistor and a second adjustable resistor, the first adjustable resistor and the second adjustable resistor are connected in series, a node between the first adjustable resistor and the second adjustable resistor is an output end of the resistance voltage dividing unit/neutral line voltage dividing unit, the output end is connected with an input end of the voltage conditioning unit through a first input resistor/a second input resistor, and a head end of the first adjustable resistor is used for connecting any phase line/neutral line of the three-phase alternating current circuit through a protection circuit of the electric energy quality management instrument.
Preferably, the amplitude limiting circuit comprises a first diode and a second diode, and a node at which the anode of the first diode is connected with the cathode of the second diode is connected with the output end of the voltage conditioning unit in parallel.
Preferably, a third resistor is arranged in series between the output end of the voltage conditioning unit and the amplitude limiting circuit, so as to avoid gain distortion.
Preferably, a third filter capacitor is arranged between the third resistor and the amplitude limiting circuit in parallel.
Preferably, the amplitude limiting unit includes a third diode and a fourth diode, and the third diode and the fourth diode are connected end to end and then connected in parallel between the inverting input terminal and the non-inverting input terminal of the first operational amplifier.
The utility model has the following beneficial effects: the three-phase voltage sampling and conditioning unit comprises a resistance voltage dividing unit, the input end of the resistance voltage dividing unit is used for being connected with any phase line of a three-phase alternating current circuit through a protection circuit of an electric energy quality treatment instrument, the output end of the resistance voltage dividing unit is connected with the input end of a voltage conditioning unit, the output end of the voltage conditioning unit is connected with the input end of a limiting circuit, the output end of the limiting circuit is used for being connected with an ADC (analog to digital converter), each voltage conditioning unit of the three-phase voltage sampling and conditioning units is connected to the output end of a neutral line voltage dividing unit in parallel, and the input end of the neutral line voltage dividing unit is used for being connected with a neutral line;
the voltage conditioning unit includes that first fortune is put, the inverting input that first fortune was put is connected with the output of resistance voltage divider unit through first input resistance, the inverting input that first fortune was put is connected with the output that first fortune was put through a feedback resistance, the homophase input that each first fortune that three-phase voltage sampling conditioning unit was put all is connected with the output of neutral line voltage divider unit through second input resistance, a ground resistance that connects in parallel between the homophase input that second input resistance and first fortune were put, an amplitude limiting unit that connects in parallel between the inverting input that first fortune was put and the homophase input for prevent that first fortune from putting by high voltage breakdown.
Preferably, a filter circuit unit is arranged between the voltage conditioning unit and the amplitude limiting circuit and used for filtering.
Preferably, the filter circuit unit is a second-order active low-pass filter circuit for filtering out high-frequency voltage components.
Preferably, the filter circuit unit comprises a second operational amplifier, a first resistor and a second resistor are sequentially connected in series between a non-inverting input end of the second operational amplifier and an output end of the voltage conditioning unit, a first filter capacitor is connected in parallel between the first resistor and the second resistor, and the first filter capacitor is grounded;
the inverting input end of the second operational amplifier is connected with the output end of the second operational amplifier, and the output end of the second operational amplifier is connected with the input end of the amplitude limiting circuit;
and a second filter capacitor is connected in parallel between the non-inverting input end and the inverting input end of the second operational amplifier.
Preferably, a voltage raising resistor is connected in parallel between the first resistor and the second resistor and used for raising the input voltage of the second operational amplifier, because the second operational amplifier actually forms a voltage following circuit, the output voltage is equal to the input voltage, raising the input voltage of the second operational amplifier is equivalent to raising the output voltage of the second operational amplifier, and finally the voltage input to the ADC is raised so as to meet the requirement that the sampling range of part of the ADC is greater than 0.
Preferably, the resistance voltage dividing unit/neutral line voltage dividing unit includes a first adjustable resistor and a second adjustable resistor, the first adjustable resistor and the second adjustable resistor are connected in series, a node between the first adjustable resistor and the second adjustable resistor is an output end of the resistance voltage dividing unit/neutral line voltage dividing unit, the output end is connected with an input end of the voltage conditioning unit through a first input resistor/a second input resistor, a head end of the first adjustable resistor is used for connecting any phase line/neutral line of the three-phase alternating current circuit through a protection circuit of the electric energy quality treatment instrument, and a tail end of the second adjustable resistor is grounded.
The first adjustable resistor is located at the head end of the resistor voltage division unit, and the second adjustable resistor is located at the tail end of the resistor voltage division unit.
Preferably, the amplitude limiting circuit comprises a first diode and a second diode, and a node at which the anode of the first diode is connected with the cathode of the second diode is connected with the output end of the voltage conditioning unit in parallel.
Preferably, a third resistor is arranged in series between the output end of the voltage conditioning unit and the amplitude limiting circuit, and is used for avoiding gain distortion of the back-end analog-to-digital converter ADC.
Preferably, a third filter capacitor is arranged between the third resistor and the amplitude limiting circuit in parallel.
Preferably, the amplitude limiting unit includes a third diode and a fourth diode, and the third diode and the fourth diode are connected end to end and then connected in parallel between the inverting input terminal and the non-inverting input terminal of the first operational amplifier.
Aiming at signal acquisition of three-phase four-wire system power grid voltage, the utility model carries out resistance voltage division and amplitude reduction on the signal, and then converts the signal into an electric signal suitable for an analog-digital converter through isolation protection, filtering, amplitude limiting and the like, and has the advantages that:
the designed resistance voltage division circuit can realize the function of the traditional mutual inductor, the use of the mutual inductor is omitted, the circuit structure is simple, and the engineering cost is greatly reduced;
the input differential mode protection and the output amplitude limiting protection controlled by the operational amplifier can effectively realize the protection of the operational amplifier and the protection of a subsequent analog-digital converter;
the designed filter circuit is a second-order active low-pass filter, so that high-frequency components can be effectively filtered, and required voltage quality information can be obtained;
and the three-phase voltage sampling and conditioning unit is suitable for the common three-phase four-wire system structure of the existing power grid.
Drawings
FIG. 1 is a schematic diagram of the present invention;
FIG. 2 is a circuit diagram of an embodiment of the present invention.
Detailed Description
As shown in fig. 1 to 2, a three-phase voltage sampling and conditioning circuit based on a resistance voltage division method includes three-phase voltage sampling and conditioning units and a neutral line voltage division unit, the three-phase voltage sampling and conditioning unit includes a resistance voltage division unit, an input end of the resistance voltage division unit is used for connecting any phase line of a three-phase alternating current circuit, in this embodiment, an input end of the resistance voltage division unit in the three-phase voltage sampling and conditioning units is respectively connected with a phase line of the three-phase alternating current circuit a/B/C through a protection circuit of an electric energy quality management instrument, and the three-phase voltage sampling and conditioning circuit is implemented by taking 380V, which is a currently commonly used three-wire four-wire system, as an example.
The output end of the resistance voltage division unit is connected with the input end of a voltage conditioning unit, the output end of the voltage conditioning unit is connected with the input end of a limiting circuit, the output end of the limiting circuit is used for connecting an ADC, each voltage conditioning unit of the three-phase voltage sampling conditioning units is connected in parallel with the output end of the neutral line voltage division unit, and the input end of the neutral line voltage division unit is used for connecting a neutral line.
The resistance voltage division unit/neutral line voltage division unit comprises a first adjustable resistor and a second adjustable resistor, the first adjustable resistor and the second adjustable resistor are connected in series, a node between the first adjustable resistor and the second adjustable resistor is an output end of the resistance voltage division unit/neutral line voltage division unit and is connected with an input end of the voltage conditioning unit through a first input resistor/a second input resistor, and the head end of the first adjustable resistor is used for connecting any phase line/neutral line of a three-phase alternating current circuit through a protection circuit of an electric energy quality improvement instrument.
In this embodiment, the resistance of the first adjustable resistor is 600k Ω, and four resistors with resistance of 150k Ω are connected in series to form a resistor with resistance of 600k Ω, which is specifically as follows:
the first adjustable resistor of the resistor voltage division unit connected with the phase line A through the protection circuit of the power quality treatment instrument is formed by serially connecting a resistor R3, a resistor R4, a resistor R5 and a resistor R6;
the first adjustable resistor of the resistor voltage division unit connected with the phase line B through the protection circuit of the power quality treatment instrument is formed by serially connecting a resistor R14, a resistor R15, a resistor R16 and a resistor R17;
the first adjustable resistor of the resistor voltage division unit connected with the C-phase line through the protection circuit of the power quality treatment instrument is formed by serially connecting a resistor R25, a resistor R26, a resistor R27 and a resistor R28;
the first adjustable resistor of the neutral line voltage division unit is formed by connecting a resistor R34, a resistor R35, a resistor R36 and a resistor R37 in series.
The second adjustable resistor is a resistor R11/a resistor R22/a resistor R33/a resistor R38, and the resistance value is 1k omega.
The voltage conditioning unit comprises a first operational amplifier, and in the embodiment, the first operational amplifier is an operational amplifier IC2/IC4/IC 6.
The inverting input end of the first operational amplifier is connected with the output end of the resistance voltage dividing unit through a first input resistor, in this embodiment, the first input resistor is a resistor R7/a resistor R18/a resistor R29, and the resistance values are all 10k Ω.
The inverting input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier through a feedback resistor, in this embodiment, the feedback resistor is a resistor R1/a resistor R12/a resistor R23, and the resistance values are all 20k Ω.
The non-inverting input end of each first operational amplifier of the three-phase voltage sampling and conditioning units is connected with the output end of the neutral line voltage dividing unit through a second input resistor, in this embodiment, the second input resistor is a resistor R40, and the resistance value is 10k Ω.
A ground resistor is connected in parallel between the second input resistor and the non-inverting input terminal of the first operational amplifier, in this embodiment, the ground resistor is R39, and the resistance value is 20k Ω.
And an amplitude limiting unit is connected in parallel between the inverting input end and the non-inverting input end of the first operational amplifier and used for preventing the first operational amplifier from being broken down by high voltage. In this embodiment, the amplitude limiting unit includes a third diode and a fourth diode, and the third diode and the fourth diode are connected end to end and then connected in parallel between the inverting input terminal and the non-inverting input terminal of the first operational amplifier. The third diode of this embodiment is diode D2/diode D6/diode D10, and the fourth diode is diode D3/diode D7/diode D11.
In this embodiment, a filter circuit unit is disposed between the voltage conditioning unit and the amplitude limiting circuit, and the filter circuit unit is a second-order active low-pass filter circuit and is configured to filter a high-frequency component of the voltage. The filter circuit unit comprises a second operational amplifier, and in the embodiment, the second operational amplifier is an operational amplifier IC 1/an operational amplifier IC 3/an operational amplifier IC 5.
A first resistor and a second resistor are sequentially connected in series between the non-inverting input end of the second operational amplifier and the output end of the voltage conditioning unit, a first filter capacitor is connected in parallel between the first resistor and the second resistor, and the first filter capacitor is grounded;
in this embodiment, a voltage raising resistor is connected in parallel between the first resistor and the second resistor, and is used to raise the input voltage of the second operational amplifier, and finally raise the voltage input to the ADC, so as to meet the requirement that the sampling range of part of the ADC is greater than 0. For example, the sampling range of the internal ADC of the DSP is 0-3.3V, so that the voltage needs to be increased. The voltage raising resistor is a resistor R2/a resistor R13/a resistor R24, and the resistance values are all 2k omega. The first resistor is a resistor R9/a resistor R20/a resistor R31, the second resistor is a resistor R10/a resistor R21/a resistor R32, the resistance values are all 2k omega, the first filter capacitor is a capacitor C7/a capacitor C14/a capacitor C21, the capacitance is 10nF, the cut-off frequency is 8kHz, and the filter is used for filtering high-frequency harmonics more than 50 times and keeping harmonics within 50 times.
A second filter capacitor is connected in parallel between the non-inverting input terminal and the inverting input terminal of the second operational amplifier, in this embodiment, the second filter capacitor is a capacitor C3/a capacitor C10/a capacitor C17, and the capacitance is 10 nF.
And the inverting input end of the second operational amplifier is connected with the output end of the second operational amplifier, and the output end of the second operational amplifier is connected with the input end of the amplitude limiting circuit.
In this embodiment, the clipping circuit includes a first diode and a second diode, and a node at which the anode of the first diode is connected to the cathode of the second diode is connected in parallel to the output terminal of the voltage conditioning unit, where in this embodiment, the first diode is diode D1/diode D5/diode D9, and the second diode is diode D4/diode D8/diode D12.
In this embodiment, the third resistor is a resistor R8/a resistor R19/a resistor R30, and the resistance values are all 10 Ω.
And a third filter capacitor is arranged between the third resistor and the amplitude limiting circuit in parallel, and in the embodiment, the third filter capacitor is a capacitor C4/a capacitor C11/a capacitor C18, and the capacitance is 100 pF.
In this embodiment, all diodes are switching diodes, all operational amplifiers are provided by the dual operational amplifier AD712J, and one dual operational amplifier AD712J may provide two operational amplifiers.
The dual operational amplifier AD712J adopts a dual power supply of +/-15V for power supply, and the output voltage range of the dual operational amplifier AD712J is-15V.
The voltage at VCC2 terminal is + 3.3V, and VEE2 terminal is grounded.
Taking a three-phase voltage sampling and conditioning unit connected with a three-phase alternating-current circuit a as an example, setting the input end voltage of a neutral line voltage division unit as uN, the output end voltage of the neutral line voltage division unit as uN1, the input end voltage of a resistance voltage division unit in the three-phase voltage sampling and conditioning unit as UA, the input end voltage of the resistance voltage division unit as UA1, the output end voltage of a first operational amplifier as UA2, the in-phase input end voltage of a second operational amplifier as UA3, and the output end voltage of a limiting circuit as UA, specifically, the calculation process is as follows:
in the formula, resistance values of the resistor R3, the resistor R4, the resistor R5, the resistor R6, the resistor R34, the resistor R35, the resistor R36 and the resistor R37 are all 150k Ω, resistance values of the resistor R11 and the resistor R38 are 1k Ω, and a calculation formula of the input end voltage ua1 of the resistor voltage dividing unit and the output end voltage uN1 of the neutral voltage dividing unit can be simplified as follows:
and the output terminal voltage ua2 of the first op-amp is calculated according to the following formula:
in the formula, the resistance values of the resistor R7 and the resistor R40 are both 10k Ω, and the resistance values of the resistor R39 and the resistor R1 are both 20k Ω, so the calculation formula of ua2 can be simplified as follows:
ua2≈2(uN1-ua1)
combining the calculation formulas of the uN1 and the ua, the calculation formula of the ua2 is further simplified as follows:
ua2≈(uN-ua)/300
through the voltage boost circuit, the calculation formula of the non-inverting input voltage ua3 of the second operational amplifier is as follows:
in the formula, the resistance R9 and the resistance R2 are both 2k Ω, and VCC3 is 3.3V, then the calculation formula of ua3 can be simplified as follows:
ua3＝1.65V+ua2/2
in combination with the above calculation formula of ua2, the calculation formula of ua3 is further simplified as follows:
ua3＝1.65V+(uN-ua)/600
the output end voltage UA of the amplitude limiting circuit is equal to UA3, that is, the calculation formula of the finally processed a-phase voltage is as follows:
UA＝1.65V+(uN-ua)/600
for a currently common three-wire four-wire system power grid of 380V, the effective value of the phase voltage is 220V, and the waveform of the phase voltage is a sine wave of-311V. The UA range obtained by combining the calculation of the above formula is 1.132V-2.168V, and the requirement that the internal ADC sampling range of a digital signal processor DSP is 0-3.3V is met.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and modifications of the present invention by those skilled in the art are within the scope of the present invention without departing from the spirit of the present invention.
Claims (10)
1. A three-phase voltage sampling and conditioning circuit based on a resistance voltage division method is characterized by comprising three-phase voltage sampling and conditioning units and a neutral line voltage division unit, wherein each three-phase voltage sampling and conditioning unit comprises a resistance voltage division unit, the input end of each resistance voltage division unit is used for being connected with any phase line of a three-phase alternating current circuit through a protection circuit of an electric energy quality management instrument, the output end of each resistance voltage division unit is connected with the input end of a voltage conditioning unit, the output end of each voltage conditioning unit is connected with the input end of a limiting circuit, the output end of each limiting circuit is connected with an ADC (analog to digital converter), each voltage conditioning unit of the three-phase voltage sampling and conditioning units is connected to the output end of the neutral line voltage division unit in parallel, and the input end of the neutral line voltage division unit is connected with a neutral line;
the voltage conditioning unit includes that first fortune is put, the inverting input that first fortune was put is connected with the output of resistance voltage divider unit through first input resistance, the inverting input that first fortune was put is connected with the output that first fortune was put through a feedback resistance, the homophase input that each first fortune that three-phase voltage sampling conditioning unit was put all is connected with the output of neutral line voltage divider unit through second input resistance, a ground resistance that connects in parallel between the homophase input that second input resistance and first fortune were put, an amplitude limiting unit that connects in parallel between the inverting input that first fortune was put and the homophase input for prevent that first fortune from putting by high voltage breakdown.
2. The three-phase voltage sampling conditioning circuit of claim 1, characterized in that: and a filter circuit unit is arranged between the voltage conditioning unit and the amplitude limiting circuit and used for filtering.
3. The three-phase voltage sampling conditioning circuit of claim 2, characterized in that: the filter circuit unit is a second-order active low-pass filter circuit and is used for filtering voltage high-frequency components.
4. The three-phase voltage sampling conditioning circuit of claim 2 or 3, characterized in that: the filter circuit unit comprises a second operational amplifier, a first resistor and a second resistor are sequentially connected between the non-inverting input end of the second operational amplifier and the output end of the voltage conditioning unit in series, a first filter capacitor is connected between the first resistor and the second resistor in parallel, and the first filter capacitor is grounded;
the inverting input end of the second operational amplifier is connected with the output end of the second operational amplifier, and the output end of the second operational amplifier is connected with the input end of the amplitude limiting circuit;
and a second filter capacitor is connected in parallel between the non-inverting input end and the inverting input end of the second operational amplifier.
5. The three-phase voltage sampling conditioning circuit of claim 4, characterized in that: and a voltage lifting resistor is connected in parallel between the first resistor and the second resistor and is used for improving the input voltage of the second operational amplifier.
6. The three-phase voltage sampling conditioning circuit of claim 1, characterized in that: the resistance voltage division unit/neutral line voltage division unit comprises a first adjustable resistor and a second adjustable resistor, the first adjustable resistor and the second adjustable resistor are connected in series, a node between the first adjustable resistor and the second adjustable resistor is an output end of the resistance voltage division unit/neutral line voltage division unit and is connected with an input end of the voltage conditioning unit through a first input resistor/a second input resistor, and the head end of the first adjustable resistor is used for connecting any phase line/neutral line of a three-phase alternating current circuit through a protection circuit of an electric energy quality improvement instrument.
7. The three-phase voltage sampling conditioning circuit of claim 1, characterized in that: the amplitude limiting circuit comprises a first diode and a second diode, and a node connecting the anode of the first diode and the cathode of the second diode is connected with the output end of the voltage conditioning unit in parallel.
8. The three-phase voltage sampling conditioning circuit of claim 7, characterized in that: and a third resistor is arranged between the output end of the voltage conditioning unit and the amplitude limiting circuit in series and is used for avoiding gain distortion.
9. The three-phase voltage sampling conditioning circuit of claim 8, characterized in that: and a third filter capacitor is arranged between the third resistor and the amplitude limiting circuit in parallel.
10. The three-phase voltage sampling conditioning circuit of claim 1, characterized in that: the amplitude limiting unit comprises a third diode and a fourth diode, and the third diode and the fourth diode are connected end to end and then connected in parallel between the inverting input end and the non-inverting input end of the first operational amplifier.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117879611A (en) * | 2024-03-12 | 2024-04-12 | 浙江华昱欣科技有限公司 | Three-phase differential sampling circuit, optimization method thereof and inverter |
| CN117879611B (en) * | 2024-03-12 | 2024-06-04 | 浙江华昱欣科技有限公司 | Three-phase differential sampling circuit, optimization method thereof and inverter |
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2021
- 2021-11-26 CN CN202122928430.8U patent/CN216771835U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117879611A (en) * | 2024-03-12 | 2024-04-12 | 浙江华昱欣科技有限公司 | Three-phase differential sampling circuit, optimization method thereof and inverter |
| CN117879611B (en) * | 2024-03-12 | 2024-06-04 | 浙江华昱欣科技有限公司 | Three-phase differential sampling circuit, optimization method thereof and inverter |
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