CN209690401U - A kind of alternating voltage DC component detection circuit - Google Patents
A kind of alternating voltage DC component detection circuit Download PDFInfo
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- CN209690401U CN209690401U CN201920046004.1U CN201920046004U CN209690401U CN 209690401 U CN209690401 U CN 209690401U CN 201920046004 U CN201920046004 U CN 201920046004U CN 209690401 U CN209690401 U CN 209690401U
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Abstract
A kind of alternating voltage DC component detection circuit, belongs to inverter field, including the low-pass filter circuit, voltage follower circuit and the signal condition that are sequentially connected electrically and amplifying circuit；Low-pass filter circuit is for extracting DC offset voltage in ac voltage signal；Signal impedance matching and isolation conditioning of the voltage follower circuit for DC offset voltage；The signal condition and amplification of signal condition and amplifying circuit for DC offset voltage.The lesser direct current biasing of amplitude is extracted from the biggish of ac of voltage magnitude, utilize the voltage follow function of operational amplifier, DC bias signal is handled, signal can be effectively improved and enter the impedance matching before operational amplifier, it is equivalent to input, the output signal progress isolation processing for entering follower, common mode interference can be effectively suppressed, direct current biasing still can be precisely detected when inverter system is harassed and occurred by biggish common mode, provides necessary condition for the inhibition of inverter system DC component.
Description
Technical field
The utility model belongs to inverter field more particularly to a kind of alternating voltage DC component detection circuit.
Background technique
Inverter class product ac output voltage always contains the direct current of suitable ingredient due to device, control equal error
Amount.Relevant national standard requires inverter output voltage direct current biasing to require within ± 100mV, and existing inverter product is related
The inhibition of DC component, since the detection accuracy by DC component is limited, inhibitory effect is undesirable, especially inverter system
In the more significant topological structure of common mode interference, DC component detection circuit is since ability resistant to common code interference is weaker, and precision is more
Add and is difficult to ensure.
In existing inverter product, the acquisition of DC component is by the way of traditional, i.e., ac voltage signal passes through first
It crosses using after resistance decrement, is filtered into low-pass filter, extracts the direct current biasing in AC signal, then through transporting
The A/D mouth of DSP or microprocessor is sent into after calculation amplifier ratio enlargement.The program is the disadvantage is that low-pass filter exported after handling
Signal, when being sent into operational amplifier processing vulnerable to inverter system common mode interference.The A/D mouth voltage of the micro processs such as DSP compared with
It is low, in links such as signal acquisition, conditionings vulnerable to external interference.Inverter is the system of a progress power conversion, inside
All the time it is likely to that biggish di/dt, du/dt occurs, therefore inverter system is that an electromagnetic interference is complex, tight
The system of weight.When switching device high-frequency work in system, just has biggish common mode harassing and wrecking signal and generate.Traditional direct current point
Amount detection circuit does not consider the precision of signal acquisition when common mode interference occurs, therefore DC component detection and processing just will receive sternly
The influence of weight.
Summary of the invention
The utility model aims to solve the problem that the above problem, and inverter class product ac output voltage can precisely be acquired by providing one kind
DC offset voltage alternating voltage DC component detection circuit.
Alternating voltage DC component detection circuit described in the utility model, including be sequentially connected electrically low-pass filter circuit,
Voltage follower circuit and signal condition and amplifying circuit；The low-pass filter circuit is used for direct current biasing in ac voltage signal
Voltage extracts；Signal impedance matching and isolation conditioning of the voltage follower circuit for DC offset voltage；The letter
Number conditioning and amplifying circuit for DC offset voltage signal condition and amplification.
Alternating voltage DC component detection circuit described in the utility model, the low-pass filter circuit include being sequentially connected electrically
Low-pass filter I and low-pass filter II；The low-pass filter I includes the resistance R being arranged in parallel1With resistance R2；The electricity
Hinder R1With resistance R2Output end between be provided with capacitor C1；The low-pass filter II includes resistance R3, resistance R4, resistance R5With
Resistance R6；The resistance R3With resistance R5It is sequentially connected and connects；The resistance R4With resistance R6It is sequentially connected and connects；The resistance R3With electricity
Hinder R4Output end between be provided with capacitor C2；The resistance R1With resistance R3It is sequentially connected and connects；The resistance R2With resistance R4According to
It is secondary to be connected.Resistance R1, resistance R2With capacitor C1Form symmetrical low-pass filter I, resistance R3, resistance R4With capacitor C2Group is pairs of
The low-pass filter II of title, resistance R5, resistance R6Cooperation late-class circuit plays the work to DC offset voltage decaying and impedance matching
With.
Alternating voltage DC component detection circuit described in the utility model, the voltage follower circuit include resistance R7, electricity
Hinder R8, resistance R9, resistance R10, capacitor C3, capacitor C4, operational amplifier U1With operational amplifier U2；The resistance R7Input terminal
With aforementioned resistance R5Output end be connected；The resistance R7Output end and operational amplifier U1Non-inverting input terminal be connected；
The resistance R9One end and resistance R7Output end be connected, the other end ground connection；The capacitor C3With resistance R9It is arranged in parallel；
The resistance R8Input terminal and aforementioned resistance R6Output end be connected；The resistance R8Output end and operational amplifier U2
Non-inverting input terminal be connected；The resistance R10One end and resistance R8Output end be connected, the other end ground connection；The capacitor
C4With resistance R10It is arranged in parallel；The operational amplifier U1Inverting input terminal be connected with output end；The operational amplifier U2
Inverting input terminal be connected with output end.
Alternating voltage DC component detection circuit described in the utility model, the signal condition and amplifying circuit include resistance
R11, resistance R12, resistance R13, resistance R14, resistance R15, capacitor C5, capacitor C6With operational amplifier U3；The resistance R11Input
End and aforementioned opamp U1Defeated end be connected；The resistance R11Output end and operational amplifier U3Non-inverting input terminal
It is connected；The resistance R13One end and resistance R11Output end be connected, another termination standard bias voltage；The resistance
R12Input terminal and aforementioned opamp U2Output end be connected；The resistance R12Output end and operational amplifier U3's
Inverting input terminal is connected；The resistance R14One end and resistance R12Output end be connected, the other end and operational amplifier U3
Output end be connected；The capacitor C5With resistance R14It is arranged in parallel；The resistance R15Input terminal and operational amplifier U3's
Output end is connected；The capacitor C6One end and resistance R15Output end be connected, the other end ground connection.
Alternating voltage DC component detection circuit described in the utility model, the resistance R1With resistance R2Output end between
It is provided with Zener diode；The Zener diode and capacitor C1It is arranged in parallel.
Alternating voltage DC component detection circuit described in the utility model, Zener diode include concatenated Zener diode
D1With Zener diode D2；The Zener diode D1With Zener diode D2It is arranged using the connection type of common-anode, i.e. Zener
Diode D1Anode and Zener diode D2Anode be connected, Zener diode D1With Zener diode D2Cathode difference
With capacitor C1Both ends be connected；When DC offset voltage is timing, i.e. the end L input voltage is higher than N-terminal input voltage, D2It is positive
Conducting, to protect the voltage for entering voltage follower to be unlikely to excessively high, D1Play the role of the clamper voltage；When direct current biasing electricity
When pressure is negative, i.e., the end L input voltage is lower than N-terminal input voltage, D1Forward conduction, D2Clamper is carried out to this bias voltage.
Alternating voltage DC component detection circuit described in the utility model can precisely acquire the exchange output of inverter class product
The DC offset voltage of voltage, the mechanism that alternating voltage DC component detection circuit occurs according to common mode interference source, fundamentally
It eliminates or reduces common mode interference as far as possible, the lesser direct current biasing of amplitude is extracted from the biggish of ac of voltage magnitude,
Using the voltage follow function of operational amplifier, DC bias signal is handled, signal can be effectively improved enters operation and put
Impedance matching before big device, substantial equivalents, can be effective in carrying out isolation processing to the input into follower, output signal
Inhibit common mode interference, still can precisely detect direct current biasing when inverter system is harassed and occurred by biggish common mode, is inversion
The inhibition of device system dc component provides necessary condition.
Detailed description of the invention
Fig. 1 is alternating voltage DC component detection circuit structural schematic diagram described in the utility model；
Fig. 2 is the alternating voltage DC component detection circuit structural representation of not set voltage follower circuit described in embodiment
Figure.
Specific embodiment
Alternating voltage DC component detection circuit described in the utility model is carried out with reference to the accompanying drawings and embodiments detailed
Explanation.
Alternating voltage DC component detection circuit described in the utility model, including be sequentially connected electrically low-pass filter circuit,
Voltage follower circuit and signal condition and amplifying circuit；The low-pass filter circuit is used for direct current biasing in ac voltage signal
Voltage extracts；Signal impedance matching and isolation conditioning of the voltage follower circuit for DC offset voltage；The letter
Number conditioning and amplifying circuit for DC offset voltage signal condition and amplification.Alternating voltage direct current described in the utility model
Component detecting circuit can be applied in the output DC bias signal detection of inverter class product, such as UPS, photovoltaic DC-to-AC converter etc.
In the detection circuit of product.
Alternating voltage DC component detection circuit described in the utility model, as shown in Figure 1, the low-pass filter circuit includes
The low-pass filter I and low-pass filter II being sequentially connected electrically；The low-pass filter I includes the resistance R being arranged in parallel1And electricity
Hinder R2；The resistance R1With resistance R2Output end between be provided with capacitor C1；The low-pass filter II includes resistance R3, resistance
R4, resistance R5With resistance R6；The resistance R3With resistance R5It is sequentially connected and connects；The resistance R4With resistance R6It is sequentially connected and connects；Institute
State resistance R3With resistance R4Output end between be provided with capacitor C2；The resistance R1With resistance R3It is sequentially connected and connects；The resistance
R2With resistance R4It is sequentially connected and connects.The resistance R1With resistance R2Output end between be provided with Zener diode；The Zener two
Pole pipe and capacitor C1It is arranged in parallel.Zener diode includes concatenated Zener diode D1With Zener diode D2。
Ac voltage signal is sent into low-pass filter input port, to friendship after two groups of symmetrical resistance are decayed
The DC component of stream voltage signal is extracted for the first time, selects filter cutoff frequency appropriate, it is right due to filter to prevent
Direct current signal generates decaying.
Resistance R in low-pass filter I1, resistance R2Play the role of two: on the one hand the high-voltage signal by exchange output is decayed
For low-voltage signal, another aspect, with capacitor C1The low-pass filter for constituting RC, filters out the ingredient of high frequency.Zener diode D1、D2
Effect are as follows: have a power failure or booting moment when being exported in inverter ac, when alternating signal has not yet been formed, DC component is very this moment
Greatly, clamper is carried out to filtered signal, prevents overtension from damaging rear class element.
Resistance R in low-pass filter II3, resistance R4Effect be that secondary filtering tune is carried out to the signal of low-pass filter I
Reason, the ingredient of high frequency is decayed again, extracts flip-flop.Resistance R5, resistance R6Cooperation late-class circuit is played to flip-flop
The effect of decaying and impedance matching.
The voltage follower circuit includes resistance R7, resistance R8, resistance R9, resistance R10, capacitor C3, capacitor C4, operation amplifier
Device U1With operational amplifier U2；The resistance R7Input terminal and aforementioned resistance R5Output end be connected；The resistance R7It is defeated
Outlet and operational amplifier U1Non-inverting input terminal be connected；The resistance R9One end and resistance R7Output end be connected, separately
One end ground connection；The capacitor C3With resistance R9It is arranged in parallel；The resistance R8Input terminal and aforementioned resistance R6Output end be connected
It connects；The resistance R8Output end and operational amplifier U2Non-inverting input terminal be connected；The resistance R10One end and resistance R8
Output end be connected, the other end ground connection；The capacitor C4With resistance R10It is arranged in parallel；The operational amplifier U1Reverse phase it is defeated
Enter end to be connected with output end；The operational amplifier U2Inverting input terminal be connected with output end.
By the high input impedance of voltage follower circuit and the characteristic of low output impedance, being equivalent to will be at prime low-pass filtering
The DC bias signal managed amplifies, and the signal is made to have certain intensity, so as to have certain support to interference source
Anti- ability, it is ensured that before carrying out rear class processing distortion caused by due to interference etc. does not occur for signal.
It is smaller to voltage magnitude, signal is weaker in addition, the characteristic of voltage follower circuit high input impedance and low output impedance
Direct current configuration component can also play the role of isolation, i.e. the input terminal of voltage follower is played with output end is isolated,
Interfering for caused by prime to be effectively isolated.
In voltage follower circuit, resistance R7, resistance R9With resistance R8, resistance R10The effect of two symmetrical resistor networks is
Decaying and impedance matching, two resistor network connection type phases are carried out to the signal for the operational amplifier for entering voltage follower circuit
Together, the direct current signal of positively biased and the direct current signal of negative film can effectively be extracted.Meanwhile capacitor C3、C4It can be to entrance voltage follower
Signal carries out necessary filtering.Two input ports and operational amplifier U1、U2Anode connection, the cathode of operational amplifier with
Output connection, forms the voltage follower of standard, and this two input ports respectively enter pair of two voltage followers
The strong electromagnetic interference of system can be effectively suppressed in the form of title.The voltage follower being made of operational amplifier, input impedance
It is very very big, and output impedance is very small, and the effect of isolation is equivalent in the effect of signal condition.
The signal condition and amplifying circuit include resistance R11, resistance R12, resistance R13, resistance R14, resistance R15, capacitor C5、
Capacitor C6With operational amplifier U3；The resistance R11Input terminal and aforementioned opamp U1Defeated end be connected；The resistance
R11Output end and operational amplifier U3Non-inverting input terminal be connected；The resistance R13One end and resistance R11Output end
It is connected, another termination standard bias voltage；The resistance R12Input terminal and aforementioned opamp U2Output end be connected
It connects；The resistance R12Output end and operational amplifier U3Inverting input terminal be connected；The resistance R14One end and resistance
R12Output end be connected, the other end and operational amplifier U3Output end be connected；The capacitor C5With resistance R14Parallel connection is set
It sets；The resistance R15Input terminal and operational amplifier U3Output end be connected；The capacitor C6One end and resistance R15's
Output end is connected, other end ground connection；Resistance R15Output end external controller the port A/D.
Signal condition and the amplifying circuit signal conditioned to voltage follower circuit are amplified with differential amplifier circuit
Processing, the circuit can also effectively prevent common mode interference, it is ensured that signal is undistorted before the port A/D for entering controller.Direct current is inclined
It sets in signal condition and amplifying circuit, resistance R11, resistance R13It may be positive value or the offset signal of negative value by this, utilize 1.65V
Standard bias voltage pull-up, becomes after DSP or certain controller A/D identifiable 0 to 3.3V signal.Resistance R12, resistance R14With
Operational amplifier U3Cooperation carries out ratio enlargement processing, capacitor C to DC bias signal5While ratio enlargement, to conditioning
Circuit increases integral element and increases the acquisition precision of circuit to reduce error.Resistance R15With capacitor C6Constitute low-pass filtering
Device carries out low-pass filtering to the output signal of conditioning circuit before the A/D mouth for entering controller, and the high frequency eliminated in route is made an uproar
Sound.
In the exchange output of the present embodiment UPS, exchange letter can precisely be acquired using detection circuit described in the utility model
DC offset voltage in number, and the DC offset voltage is introduced into the algorithm of control system and is handled, to symmetrical inverse
Become the biasing control that device system carries out opposite direction, the direct current biasing of AC signal can be inherently eliminated, prevented since this is straight
Problems caused by stream biasing.
In the present embodiment, for the ups system of 10kW, alternating current described in the utility model as shown in Figure 1 is respectively adopted
Press the alternating voltage DC component detection circuit of DC component detection circuit and not set voltage follower circuit as shown in Figure 2 into
Row detection.In two kinds of different circuits, it is divided to two kinds of processing: first, by being safely reliably connected to distribution system for ups system
It is safely PE, it is well known that reliable ground can provide relatively straightforward return flow path for electromagnetic interference signal, to reduce and be
System electromagnetic interference；Second, the grounding point of ups system is hanging, i.e., do not connect with the PE of distribution system, the first opposite processing,
System electromagnetic interference can be to each analoglike of system, number almost without return flow path, electromagnetic interference signal under such operating condition
Signal has certain interference, which will be far seriously in the processing of the first reliable ground.The processing method of both the above ground connection
Cooperate two different direct current biasing Acquisition Circuits, UPS in house software braking measure is constant, i.e. institute's test result is by direct current
The precision of component Acquisition Circuit causes.It is as shown in table 1 that actual test exchanges output DC component data.
Table 1
From upper table test result as it can be seen that sampling Acquisition Circuit shown in FIG. 1, i.e., alternating voltage direct current described in the utility model
Component detecting circuit, no matter ups system reliable ground whether, by braking measure inside UPS, the effect that DC component is inhibited
Well, the relevant criterion requirement within satisfaction ± 100mV.Using traditional Acquisition Circuit of Fig. 2, in ups system reliable ground
Though it is able to satisfy standard requirements in the case of, but it is inferior with Fig. 1 circuit, and in the earth-free situation of ups system, inhibitory effect
It cannot meet the requirements, than having apparent difference using the effect of Fig. 1 circuit.Alternating voltage direct current described in the utility model as a result,
Component detecting circuit has apparent advantage for the acquisition precision of the DC component of exchange output under strong electromagnetic, to friendship
Stream signal is decayed, after low-pass filtering treatment, before carrying out signal amplification into operational amplifier, passes through the place of voltage follower
Reason.The advantages of voltage follower is that input impedance is larger, and output impedance is smaller, and therefore, the signal after filtering processing is played
The effect of impedance matching.In addition, high input impedance and low output impedance be equivalent to for input, output signal every
From to play the effect for inhibiting common mode interference.By the test of Inverter Experimental model machine, under high-intensitive common mode interference
DC offset voltage can precisely be obtained.
Claims (6)
1. a kind of alternating voltage DC component detection circuit, it is characterised in that: including low-pass filter circuit, the electricity being sequentially connected electrically
Pressure follows circuit and signal condition and amplifying circuit；The low-pass filter circuit is used for direct current biasing electricity in ac voltage signal
Pressure extracts；Signal impedance matching and isolation conditioning of the voltage follower circuit for DC offset voltage；The signal
The signal condition and amplification of conditioning and amplifying circuit for DC offset voltage.
2. alternating voltage DC component detection circuit according to claim 1, it is characterised in that: the low-pass filter circuit packet
Include the low-pass filter I and low-pass filter II being sequentially connected electrically；The low-pass filter I includes the resistance R being arranged in parallel1With
Resistance R2；The resistance R1With resistance R2Output end between be provided with capacitor C1；The low-pass filter II includes resistance R3, electricity
Hinder R4, resistance R5With resistance R6；The resistance R3With resistance R5It is sequentially connected and connects；The resistance R4With resistance R6It is sequentially connected and connects；
The resistance R3With resistance R4Output end between be provided with capacitor C2；The resistance R1With resistance R3It is sequentially connected and connects；The electricity
Hinder R2With resistance R4It is sequentially connected and connects.
3. alternating voltage DC component detection circuit according to claim 2, it is characterised in that: the voltage follower circuit packet
Include resistance R7, resistance R8, resistance R9, resistance R10, capacitor C3, capacitor C4, operational amplifier U1With operational amplifier U2；The resistance
R7Input terminal and aforementioned resistance R5Output end be connected；The resistance R7Output end and operational amplifier U1It is same mutually defeated
Enter end to be connected；The resistance R9One end and resistance R7Output end be connected, the other end ground connection；The capacitor C3With resistance
R9It is arranged in parallel；The resistance R8Input terminal and aforementioned resistance R6Output end be connected；The resistance R8Output end and fortune
Calculate amplifier U2Non-inverting input terminal be connected；The resistance R10One end and resistance R8Output end be connected, another termination
Ground；The capacitor C4With resistance R10It is arranged in parallel；The operational amplifier U1Inverting input terminal be connected with output end；It is described
Operational amplifier U2Inverting input terminal be connected with output end.
4. alternating voltage DC component detection circuit according to claim 3, it is characterised in that: the signal condition and amplification
Circuit includes resistance R11, resistance R12, resistance R13, resistance R14, resistance R15, capacitor C5, capacitor C6With operational amplifier U3；It is described
Resistance R11Input terminal and aforementioned opamp U1Defeated end be connected；The resistance R11Output end and operational amplifier U3
Non-inverting input terminal be connected；The resistance R13One end and resistance R11Output end be connected, another termination standard bias electricity
Pressure；The resistance R12Input terminal and aforementioned opamp U2Output end be connected；The resistance R12Output end and fortune
Calculate amplifier U3Inverting input terminal be connected；The resistance R14One end and resistance R12Output end be connected, the other end with
Operational amplifier U3Output end be connected；The capacitor C5With resistance R14It is arranged in parallel；The resistance R15Input terminal and fortune
Calculate amplifier U3Output end be connected；The capacitor C6One end and resistance R15Output end be connected, the other end ground connection.
5. according to the alternating voltage DC component detection circuit of claim 2 or 4, it is characterised in that: the resistance R1And resistance
R2Output end between be provided with Zener diode；The Zener diode and capacitor C1It is arranged in parallel.
6. alternating voltage DC component detection circuit according to claim 5, it is characterised in that: Zener diode includes series connection
Zener diode D1With Zener diode D2；The Zener diode D1With Zener diode D2Using the connection side of common-anode
Formula setting.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920046004.1U CN209690401U (en) | 2019-01-11 | 2019-01-11 | A kind of alternating voltage DC component detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920046004.1U CN209690401U (en) | 2019-01-11 | 2019-01-11 | A kind of alternating voltage DC component detection circuit |
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| Publication Number | Publication Date |
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| CN209690401U true CN209690401U (en) | 2019-11-26 |
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| CN201920046004.1U Expired - Fee Related CN209690401U (en) | 2019-01-11 | 2019-01-11 | A kind of alternating voltage DC component detection circuit |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111464143A (en) * | 2020-04-03 | 2020-07-28 | 南京中岭艾恩环保科技有限公司 | Circuit for conditioning electric signals of electrostatic sensor |
| CN112946549A (en) * | 2021-01-28 | 2021-06-11 | 杭州西力智能科技股份有限公司 | Method for correcting direct current component in alternating current system |
| CN114488993A (en) * | 2021-12-20 | 2022-05-13 | 上海华兴数字科技有限公司 | Circuit state detection device and method |
| CN116643082A (en) * | 2023-07-27 | 2023-08-25 | 闽南理工学院 | AC voltage signal non-isolation measuring circuit containing DC bias and measuring method |
| CN117060490A (en) * | 2023-08-18 | 2023-11-14 | 合肥开关厂有限公司 | Control method and device for energy storage system direct current bias suppression single-phase inverter |
-
2019
- 2019-01-11 CN CN201920046004.1U patent/CN209690401U/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111464143A (en) * | 2020-04-03 | 2020-07-28 | 南京中岭艾恩环保科技有限公司 | Circuit for conditioning electric signals of electrostatic sensor |
| CN112946549A (en) * | 2021-01-28 | 2021-06-11 | 杭州西力智能科技股份有限公司 | Method for correcting direct current component in alternating current system |
| CN114488993A (en) * | 2021-12-20 | 2022-05-13 | 上海华兴数字科技有限公司 | Circuit state detection device and method |
| CN116643082A (en) * | 2023-07-27 | 2023-08-25 | 闽南理工学院 | AC voltage signal non-isolation measuring circuit containing DC bias and measuring method |
| CN116643082B (en) * | 2023-07-27 | 2024-04-19 | 闽南理工学院 | AC voltage signal non-isolation measuring circuit containing DC bias and measuring method |
| CN117060490A (en) * | 2023-08-18 | 2023-11-14 | 合肥开关厂有限公司 | Control method and device for energy storage system direct current bias suppression single-phase inverter |
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