CN115333502A - Multistage parallel active common mode interference filter and control method - Google Patents

Multistage parallel active common mode interference filter and control method Download PDF

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Publication number
CN115333502A
CN115333502A CN202211250247.XA CN202211250247A CN115333502A CN 115333502 A CN115333502 A CN 115333502A CN 202211250247 A CN202211250247 A CN 202211250247A CN 115333502 A CN115333502 A CN 115333502A
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common mode
operational amplifier
output
parallel
voltage
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蒋云昊
周高逸
蔡子硕
侯天豪
宋一鸣
袁雷
徐岸非
肖集雄
王航
杨帅
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Hubei University of Technology
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Hubei University of Technology
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Priority to CN202310323040.9A priority patent/CN116032247A/en
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H11/00—Networks using active elements
    • H03H11/02—Multiple-port networks
    • H03H11/04—Frequency selective two-port networks
    • H03H11/12—Frequency selective two-port networks using amplifiers with feedback
    • H03H11/1217—Frequency selective two-port networks using amplifiers with feedback using a plurality of operational amplifiers
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/12—Arrangements for reducing harmonics from ac input or output
    • H02M1/123—Suppression of common mode voltage or current
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/44—Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • H02M7/53871—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
    • H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
    • H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters
    • H02P27/08—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters with pulse width modulation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/40—Arrangements for reducing harmonics

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Networks Using Active Elements (AREA)

Abstract

The invention relates to the field of electromagnetic compatibility, in particular to a multistage parallel active common mode interference filter and a control method thereof. The invention adopts a multi-stage parallel structure, modifies the proportion of each stage of compensation to the total compensation, and can selectively inhibit common mode interference of different frequency bands; compared with a single-stage AEF, the filter has more stable working state and structure, still has the function of interference suppression on a system when a certain stage fails, and can continuously compensate the common-mode current when the failed stage is removed and the output resistor is modified.

Description

Multistage parallel active common mode interference filter and control method
Technical Field
The invention relates to the field of electromagnetic compatibility, in particular to a multistage parallel active common mode interference filter and a control method thereof, which are suitable for solving the problem that a circuit system is influenced by overlarge common mode interference caused by a large number of coupling stray components contained in a power terminal.
Background
Electric energy is gradually becoming the center of the current energy system as a new energy source, and the full utilization of the electric energy is an important ring for realizing clean production and green industry. As power electronic converters are receiving wide attention and research from researchers as core devices for power conversion, the power electronic devices are developed in the directions of high frequency, high power and high energy density, and thus, the power electronic devices can obtain required power and cause serious Electromagnetic Interference (EMI Interference) problems. Electromagnetic interference is commonly present in inverter systems, and EMI can be distinguished into radiated interference and conducted interference according to the difference of EMI propagation paths, wherein conducted interference is a form of interference that an interference source transmits to an interfered object in the form of voltage or current through a coupling loop. Non-ideal factors in the system can generate common-mode noise sources, such as a motor casing-to-ground stray capacitance, an inverter-to-ground stray capacitance and other coupling loops included in a motor dragging system, and therefore, a large amount of common-mode conducted interference is included. Common mode conducted interference can damage the insulation structure and the motor bearing of the motor, so that the suppression of the common mode interference in an inverter system becomes an important research direction for improving the electromagnetic environment of the whole circuit.
In practical engineering applications, researchers often add filtering devices to the circuit system to block the coupling path of conducted interference or to suppress interference by reducing the conducted emissions of the interference source. Traditional Passive electromagnetic interference filters (PEFs), such as common mode choke, LCL type Filter, etc., are difficult to reduce the volume and weight while ensuring the system power density, and have many limitations when they are used in scenes with high requirements on space utilization, such as new energy vehicles, motor-driven ships, etc. The conduction emission can be reduced to a certain extent by improving the modulation mode of the inverter, such as adopting a spread spectrum modulation technology, or redesigning a circuit board aiming at circuit elements and improving the packaging form of the elements, but the two modes can increase the complexity of the design of a main circuit and increase the cost, only a specific scene can be designed in a targeted manner, and the universality is difficult to ensure. An Active electromagnetic interference Filter (AEF) can suppress interference by extracting common-mode interference and injecting components with opposite propagation directions into a circuit to cancel the components, and the system does not have large volume change due to no adoption of elements such as a coil and a mutual inductor, so that the system does not have increased volume basically, and the working characteristics of the AEF externally hung on a main circuit make the AEF rich in use scenes. However, because the operating band of circuit elements such as operational amplifiers included in the AEF is fixed, the unoptimized AEF has weak capability of suppressing common mode interference and poor reliability, and the invention intends to improve the AEF.
The invention aims to adopt a multistage parallel Voltage detection current compensation (VSCC) active electromagnetic interference filter to solve the problem of poor interference suppression effect when a single AEF is used. Aiming at the problem of fixed working bandwidth of circuit elements such as operational amplifier and the like, the multi-level parallel connection mode utilizes multiple resistance values to compensate common-mode current sub-bands, so that the frequency band which can be compensated by the VSCC-AEF is expanded, the interference suppression effect of a certain specific frequency band is enhanced, and the VSCC-AEF has better working effect in each frequency band.
Disclosure of Invention
The invention aims to overcome the limitation of the conventional AEF on the compensation effect of common-mode interference, and provides a multistage parallel active common-mode interference filter, which can compensate common-mode current by adopting a plurality of reverse amplification resistance values, so that the rejection capability of the AEF on the common-mode interference is enhanced, and meanwhile, the filter also has a better rejection effect on certain specific frequency points.
The technical problem of the invention is mainly solved by the following technical scheme:
a multi-stage parallel active common mode interference filter comprising:
a main circuit: the inverter is used for forming a common mode interference conduction loop through equivalent common mode impedance grounding of a motor at the output side of the inverter and an inverter ground coupling capacitor;
the common-mode voltage detection network module: the voltage-reducing circuit is used for extracting and reducing the voltage according to a certain proportion to generate a waveform with the same form as the common-mode voltage as the input voltage of the improved AEF;
the multistage parallel reverse amplification network module: the operational amplifier generates voltages required by compensation of each frequency band through the same equivalent common-mode input impedance and the reverse amplification resistors with different sizes;
a compensation current injection module: the current compensation circuit is used for generating compensation current required by each section, summarizing the section current, and injecting summarized current into a main circuit to counteract the original common-mode total current so as to inhibit common-mode interference.
In the above multistage parallel active electromagnetic interference filter, the main circuit includes an inverter and a line impedance stabilization network LISN connected in parallel to the dc side of the inverter; DC power supply generated by rectification circuitU DC The positive and negative two stages are connected between the positive and negative poles of the LISN, the LISN is output to a three-phase full-bridge inverter, and the three-phase inverter inputs a series capacitor between the positive and negative polesC 1 、C 2 And the midpoint of the two capacitors is grounded to be used as a power supply neutral point O; three-phase full-bridge inversion comprises S a 、S b 、S c Three bridge arms, the inverter is driven to operate by using an SVPWM (space vector pulse width modulation) modulation mode, and the inverter outputs three-phase alternating current to pass through the equivalent common-mode impedance of the motorZ motor The output lines of three bridge arms of the inverter pass through three ground coupling capacitors respectivelyC p A ground wire is connected; wherein the motor equivalent common mode impedanceZ motor With three capacitors coupled to groundC p The parallel total impedance is the equivalent common mode total impedance of the systemZ LOAD 。
In the above multistage parallel active electromagnetic interference filter, the motor equivalent common mode impedanceZ motor One phase of (1) includes a capacitorC m1 And is andC m1 series resistance-inductance loadRL 11 And is prepared byRL 11 Series resistance-inductance loadRL 12 And is prepared byRL 11 Parallel capacitorsC m11 And a resistorR 11 And is andRL 12 parallel capacitorsC m12 And a resistorR 12 ；
Structure and motor equivalent common mode impedanceZ motor One phase of equivalent impedance with the same structure and three phases of equivalent impedance are connected in parallel to form a complete equivalent common mode impedance of the motorZ motor ；
Equivalent common mode impedance of motorZ motor Wherein each single phase is respectively connected with the equivalent ground coupling capacitor of the three-phase line output by the inverter in parallelC p1 、C p2 、C p3 To form the equivalent common mode total impedance of the systemZ LOAD In whichC p =C p1 =C p2 =C p3 。
In the aforementioned multi-stage parallel active emi filter, the common mode voltage detection network module utilizes three resistors with equal resistance respectively connected in parallel to three phase lines of the full bridge inverterR 0 And is andR 0 series connected resistorsR 1 、R 2 Collecting a common-mode voltage detection value;
will the resistanceR 2 One end of the first resistor is grounded and the other end is connected to the operational amplifierOP 1 Positive input electrode of, operational amplifierOP 1 The negative input pole and the output pole are connected to form a voltage follower; operational amplifierOP 1 Connecting driving voltage ± -2V s 。
In the aforementioned multi-stage parallel active electromagnetic interference filter, the multi-stage parallel reverse amplifying network module comprises an operational amplifierOP 21 To an operational amplifierOP 2n (ii) a Amplifying resistorR 31 To an amplifying resistorR 3n ；
Operational amplifierOP 21 Equivalent common mode impedance of negative input pole connection systemZ LOAD The positive input electrode is grounded, and the output electrode passes through an amplifying resistorR 31 Is connected with the negative input electrode; operational amplifierOP 21 Connecting driving voltage +/-V s (ii) a Operational amplifierOP 22 To an operational amplifierOP 2n In the connection mode and the operational amplifierOP 21 The same, their amplification resistance values are respectively replaced byR 32 ToR 3n 。
In the aforementioned multi-stage parallel active emi filter, the compensating current injection module includes a multi-stage push-pull circuit, a multi-stage output resistor, and an isolation capacitor, wherein an input terminal of the first-stage push-pull circuit is connected to the operational amplifier in the multi-stage parallel reverse amplification network moduleOP 21 The output end of the output resistor is connected with the output resistorR 41 ；
The connection mode of the rest multi-stage push-pull circuits is the same as that of the first-stage push-pull circuit, and the input ends of the rest multi-stage push-pull circuits are respectively connected with the operational amplifierOP 21 To an operational amplifierOP 2n Output ends of the power supply are respectively connected with output powerResistance blockR 42 ToR 4n (ii) a Will output resistance in multiple stagesR 41 ToR 4n The other end of the first capacitor is connected in parallel to a point to connect an isolation capacitorC 3 (ii) a Isolation capacitorC 3 The other end is grounded to form a complete compensation loop.
A control method of a multistage parallel active electromagnetic interference filter comprises
When the main circuit is not connected to the improved AEF, theZ motor Total current to ground isI CM1 Capacitance viaC p Total current to ground isI CM2 The total current flowing into the LISN neutral point through the ground wire isI LISNs Total common mode current of the system isI CM WhereinI CM1 + I CM2 =I LISNs =I CM Forming a common mode interference conduction loop; wherein the content of the first and second substances,Z motor and three coupling capacitorsC p The parallel total impedance is the equivalent common mode total impedance of the systemZ LOAD Is provided withU CM /Z LOAD =I CM ；
When the improved AEF is connected into a main circuit, the common-mode voltage detection network module is used for extracting and reducing according to a certain proportion, and generating a waveform with the same form as the common-mode voltage as the input voltage of the improved AEF; the multistage parallel reverse amplification network module utilizes an operational amplifier to generate voltages required by compensation of each frequency band; the compensation current injection module applies the voltage generated by the multistage parallel reverse amplification network module to the output resistor to generate and collect compensation current required by each section, and the collected current is injected into the main circuit to be mutually offset with the original common-mode current so as to inhibit common-mode interference.
In the control method of the multistage parallel active electromagnetic interference filter, when the main circuit is connected to the improved AEF, the working process of the common mode voltage detection network module is as follows: using three equal-resistance resistors respectively connected in parallel to three phase lines of full-bridge inverterR 0 And is andR 0 series connected resistorsR 1 、R 2 Collecting a common-mode voltage detection value; will the resistanceR 2 Another end is grounded and connected to a resistorR 2 Upper partial pressure value ofV sense In whichkAs resistors in impedance networksR 2 The partial pressure proportion relation of (1) is as follows:
Figure 705731DEST_PATH_IMAGE001
(1)
will the resistanceR 2 Value of partial pressureV sense Input operational amplifierOP 1 Positive input electrode of, operational amplifierOP 1 The negative input pole and the output pole are connected to form a voltage follower; the voltage output value of the voltage follower is the voltage value input into the multistage parallel reverse amplification network moduleV IN Therein is provided withV IN =V sense =kU CM 。
In the control method of the multistage parallel active electromagnetic interference filter, when the main circuit is connected to the improved AEF, the working process of the multistage parallel reverse amplification network module is as follows: operational amplifierOP 21 Equivalent common mode impedance of negative input pole connection systemZ LOAD Input ofV IN Voltage value, grounding the positive input electrode, passing the output electrode through an amplifying resistorR 31 Is connected with the negative input electrode; operational amplifierOP 21 Connecting driving voltage +/-V s The output voltage value is the voltage value of the input compensation current injection moduleV OUT1 (ii) a Operational amplifierOP 22 To an operational amplifierOP 2n Connection mode and operational amplifierOP 21 The same, the amplification resistance values are respectively changed toR 32 ToR 3n The obtained output voltage values are respectivelyV OUT2 ToV OUTn (ii) a WhereinOP 21 To is thatOP 2n Respectively have gains ofA 1 ToA n ，n=1,2,3 …, having:
Figure 419609DEST_PATH_IMAGE002
(2)。
in the control method of the multistage parallel active electromagnetic interference filter, the working process of the compensation current injection module is as follows: operational amplifier in multi-stage parallel reverse amplification network moduleOP 21 Output voltage value ofV OUT1 The input is connected to the input end of the first stage push-pull circuit, and the output end of the first stage push-pull circuit is connected with the output resistorR 41 I.e. the value of the voltageV OUT1 Applied to the output resistorR 41 To obtain a compensation currentI COMP1 ；
The working process of the rest multi-stage push-pull circuit is the same as that of the first stage push-pull circuit, and the operational amplifier is usedOP 22 To an operational amplifierOP 2n Output voltage value ofV OUT2 ToV OUTn Respectively applied to the output resistorsR 42 ToR 4n Thereby obtaining a compensation currentI COMP2 To is thatI COMPn (ii) a Order ton=1,2,3 …, having:
Figure 746816DEST_PATH_IMAGE003
(3)
compensating current to be outputI COMP1 ToI COMPn An isolation capacitor is connected in series after being connected to one point in parallelC 3 Can obtain a current flowing through the isolation capacitorC 3 Total compensation current ofI COMP (ii) a WhereinPIs a constant value representing the parallel progression of the improved AEF, and comprises:
Figure 673184DEST_PATH_IMAGE004
(4)
make the compensating currentI COMP Can cancel common mode current, need to makeI COMP =-I CM Then, there are:
Figure 18714DEST_PATH_IMAGE005
(5)
will output the compensating currentI COMP Connected to ground, in which case the common-mode interference conduction loop of the system isI CM1 +I CM2 +I COMP =I LISNs Wherein whenI COMP =-I CM =-(I CM1 +I CM2 ) When there isI LISNs =0; in this case, the detected common mode current on the LISN is reduced to suppress system common mode interference.
Compared with the existing electromagnetic interference filtering device, the electromagnetic interference filtering device has the advantages that:
1. compared with the PEF, the invention does not contain devices such as coils, mutual inductors and the like, has small volume, light weight, rich use scenes and simple use mode;
2. compared with single-stage AEF, the invention expands the amplification resistance value of the usable reverse amplification module in a multi-stage parallel mode, and can compensate for the electromagnetic interference of multiple frequency bands;
3. when the single-stage AEF is applied to a nonlinear system such as a motor system, since the common-mode impedance in the system varies with the frequency, the single amplification resistance value cannot vary according to the variation of the common-mode impedance, and thus the compensation effect is poor. The defect can be made up by adopting a multi-stage parallel connection mode and utilizing a plurality of amplification resistance values;
4. because a multi-stage parallel structure is adopted, the proportion of each stage of compensation to the total compensation is modified, and common mode interference of different frequency bands can be selectively inhibited;
5. because of adopting the multistage parallel structure, compared with a single-stage AEF, the filter has more stable working state and structure, when a certain stage fails, the filter still has the function of inhibiting interference on a system, and when the failed stage is removed and the output resistor is modified, the common-mode current can be continuously compensated.
Drawings
FIG. 1 is a schematic diagram of a three-phase full-bridge inverter system driven by SVPWM and having motor equivalent common-mode impedance as a load and a common-mode current conduction loop without adding an improved AEF;
FIG. 2 is a simplified illustration of simulation generationU CM A waveform;
FIG. 3 is a schematic diagram of a system equivalent common mode total impedance network topology;
FIG. 4 is a model of the system equivalent common mode total impedance;
FIG. 5 is a drawing showingZ LOAD Phase frequency and amplitude frequency characteristics;
FIG. 6 is a simplified common mode current propagation path topology;
FIG. 7 is a block diagram of an improved AEF operation;
FIG. 8 is a block diagram of a common mode voltage detection network;
FIG. 9 is a block diagram of a multi-stage parallel reverse amplifier network module and a compensating current injection module;
fig. 10 is a diagram of the system common mode current conduction path topology after the addition of the improved AEF.
Detailed Description
The invention will be further explained by the following figures and examples in connection with the implementation of the invention and the related technology
The specific main circuit comprises:
step 1: in order to obtain a common-mode voltage detection value of the trigger improved AEF and verify the effect of suppressing common-mode interference, a common-mode interference conduction loop in a system, an improved AEF common-mode voltage detection network module, a multi-stage parallel reverse amplification network module and a compensation current injection module are required to be modeled and analyzed.
And 2, step: DC side input DC voltage of inverterU DC As in fig. 1, the value thereof is set to 311V. DC input side between positive and negative poles of inverterTwo filter capacitors with equal series capacitanceC 1 、C 2 The neutral point of the two capacitors is grounded as the neutral point O of the power supply, the LISN is connected between the DC voltage output end and the input end of the inverter, the neutral point of the LISN is grounded, and the current flows inI LISNs 。
And 3, step 3:U a O 、U bO 、U cO respectively are voltage values between the three-phase output line of the inverter and a neutral point O point on the direct current side,U aN 、U bN 、U cN respectively equivalent common-mode impedance of three-phase output circuit of inverter and motorZ motor A voltage value between the grounding point and the N point, whereinU aO =U aN +U NO 、U bO =U bN +U NO 、U cO =U cN +U NO . The phase voltage and the line voltage values obtained according to different conduction states of the inverter are shown in table 1, wherein 0 represents that the lower bridge arm switching device is conducted, and 1 represents that the upper bridge arm switching device is conducted.
TABLE 1 phase voltages and line voltages for different conduction conditions of the switching device
Figure 388647DEST_PATH_IMAGE006
And 4, step 4: from Table 1, it is understood that the sum of the phase voltages is 0U aN +U bN +U cN =0, the system common mode voltage is the voltage value between the neutral point O of the DC side of the inverter and the grounding point N of the equivalent common mode impedance of the motorU CM =U NO =(U aO +U aN +U bO +U bN +U cO +U cN )/3=(U aO +U bO +U cO )/3. Summary of all switchesThe common mode voltage values in the inverter system under the conditions are shown in table 2.
TABLE 2 common mode voltage for each switching state of the inverter
Figure 186839DEST_PATH_IMAGE007
And 5: as can be seen from Table 2, when SVPWM modulation is used, the common mode voltage has four level states in common, a single vector synthesis switching period is set to be 0.0001s, and the common mode voltage value change sequence in the first half switching period of the SVPWM modulation mode is-1/2U DC To-1/6U DC To 1/6U DC To 1/2U DC The second half period common mode voltage waveform is symmetrical to the first half period, and MATLAB/Simulink is used to generate simplified common mode voltage waveformU CM Waveform sequence, as in fig. 2.
Step 6: due to equivalent common mode impedance of the motorZ motor The equivalent common-mode total impedance network topology of the system is shown in fig. 3, and the equivalent common-mode total impedance network topology can not change along with the change of the position of the motor rotor and needs to be modeled to serve as the input impedance of an operational amplifier in a multi-stage reverse amplification module.Z motor One phase of the capacitorC m1 And is prepared byC m1 Series resistance-inductance loadRL 11 And is prepared byRL 11 Series resistance-inductance loadRL 12 And is andRL 11 parallel capacitorsC m11 And a resistorR 11 And is andRL 12 parallel capacitorsC m12 And a resistorR 12 。
TABLE 3Z motor Value of parameter of middle element
Figure 182477DEST_PATH_IMAGE008
And 7: two-phase equivalent impedances having the same structure as that in step 6 are constructed and three-phase equivalent impedances are connected in parallel,form a completeZ motor 。
And 8: order toZ motor Each single phase is respectively connected with equivalent coupling capacitors in parallelC p1 ToC p3 Is composed ofZ LOAD Built by SimulinkZ LOAD The model, and the impedance characteristics thereof detected by the impedance measuring tool are shown in FIG. 4, in whichC p =C p1 =C p2 =C p3 =3.3pF。Z LOAD The detection results of the phase-frequency and amplitude-frequency characteristics are shown in fig. 5. The partial frequency point impedance was measured as in table 4.
TABLE 4 System equivalent common mode Total impedance part frequency Point impedance
Figure 133246DEST_PATH_IMAGE009
And 7: the simplified common mode current propagation path is shown in fig. 6, where,Z LISN is an LISN equivalent impedance to ground, with a value of 25 omega,U CM is a common-mode voltage, and is,Z LOAD for the system equivalent common mode total impedance, there areI CM =U CM / Z LOAD . Forming a common mode current loop through the ground line, whereinI LISNs =I CM 。
The three modules forming the improved AEF are respectively a common-mode voltage detection network module, a multi-stage parallel reverse amplification network module and a compensation current injection module, a structural block diagram of the working process of the improved AEF is shown in figure 7,I CM2 is the sum of the common mode currents of the three phase line-to-ground coupling capacitors of the inverter,I CM1 for equivalent impedance of motorZ motor The common-mode current to ground is set to be,I COMP for the improved AEF generated compensation current,I LISNs is the total current flowing into the LISN. WhereinI LISNs Is the sum of the common mode current and the compensation current.
The common mode voltage detection network module comprises:
step 1: the improved AEF needs to extract the common mode voltage as an input quantity, and a resistor voltage dividing network for extracting the common mode voltage is shown in fig. 8. Using three equal-resistance resistors respectively connected in parallel to three phase lines of full-bridge inverterR 0 And is andR 0 series connected resistorsR 1 ，R 2 And collecting a common-mode voltage detection value. Will be provided withR 2 Is connected in series to the neutral point of the power supply to ground,R 2 resistance voltage division valueV sense To extract the voltage values, among them:
Figure 923348DEST_PATH_IMAGE010
(1)
step 2: the AD826 operational amplifier is selected to form a voltage follower with a driving voltage of +/-V s Set to +/-15V, and since the DC side input voltage value of the inverter is 311V, the common mode amplitude value is 0.5U DC =155.5V，V sense The voltage follower can work normally only by adjusting the voltage to be less than +/-15V. Is provided withR 0 =3kΩ，R 1 =10kΩ，R 2 =1k Ω, at this timek=1/12，V sense Amplitude of 13V, operational amplifierOP 1 Value of the output voltageV IN =V sense 。
The multistage parallel reverse amplification network module comprises:
step 1: an AD826 operational amplifier is selected to form an inverting amplifier, and the system equivalent total mode impedanceZ LOAD The input impedance of the multistage parallel inverse amplification network module operational amplifier is connected in series with the input voltageV IN AndOP 21 toOP 2n See fig. 9 for operational amplifierOP 21 ToOP 2n Has an amplifying resistance ofR 31 ToR 3n Output voltageV OUT1 ToV OUTn 。
Step 2: according to the amplitude-frequency characteristic of the equivalent common-mode total impedance set in the invention, the parallel series is selectedP=3, amplify resistance according to resistance data of frequency band in table 4R 31 、R 32 、R 33 Set to 72 omega, 112 omega and 240 omega respectively, and the reverse amplification modules output voltage values respectivelyV OUT1 、V OUT2 、V OUT3 The following formula (2), whereinn=1，2，3。
Figure 208835DEST_PATH_IMAGE002
(2)
The compensation current injection module comprises:
step 1: the improved AEF compensation current is generated by a push-pull circuit and a compensation resistor, and the push-pull circuit is isolated by an isolation resistorR 5 、R 6 Set to 2000 omega, the isolation diode is 1N4148,R 7 、R 8 the setting of 5 omega prevents the push-pull circuit from thermal breakdown, and the driving voltage is +/-15V. Output voltage of preceding stageV OUT1 ToV OUT3 Are respectively applied to compensation resistorsR 41 ToR 43 To obtain a compensation currentI COMP1 ToI COMP3 Formula (3) below, where n =1,2,3.
Figure 496247DEST_PATH_IMAGE011
(3)
Will compensate the currentI COMP1 To is thatI COMP3 Connected in parallel to a point to obtain the total compensation currentI COMP 。
Figure 816370DEST_PATH_IMAGE012
(4)
Step 2: is added with a modified type AThe common mode current conduction path in the post-EF system is shown in fig. 10, and in order to cancel the common mode current existing in the system, the compensation current needs to be madeI COMP =-I CM . Then it is required to satisfy
Figure 777373DEST_PATH_IMAGE013
(5)
Figure 566468DEST_PATH_IMAGE014
(6)
Output resistorR 41 To is thatR 43 Set to 18 Ω,28 Ω,60 Ω, respectively. Connecting isolation capacitorC 3 And inputting the voltage to the ground wire to form a complete compensation loop.
An improved AEF simulation model built by using the PSPICE is utilized, and an MATLAB and PSPICE combined simulation tool is utilized to verify the improved AEF mode, so that the accuracy and the interference suppression capability are confirmed to be superior.
The above embodiments are merely illustrative and do not limit the scope of the present invention. Other modifications and additions may be made to the described embodiments or may be substituted in a similar manner by those skilled in the art without departing from the spirit of the invention or exceeding the scope thereof as defined in the appended claims.

Claims (10)

1. A multistage parallel active common mode interference filter comprising:
a main circuit: the inverter is used for forming a common mode interference conduction loop through equivalent common mode impedance grounding of a motor at the output side of the inverter and an inverter ground coupling capacitor;
the common-mode voltage detection network module: the voltage-reducing circuit is used for extracting and reducing the voltage according to a certain proportion to generate a waveform with the same form as the common-mode voltage as the input voltage of the improved AEF;
the multistage parallel reverse amplification network module: the operational amplifier generates voltages required by compensation of each frequency band through the same equivalent common-mode input impedance and the reverse amplification resistors with different sizes;
a compensation current injection module: the current compensation circuit is used for generating compensation current required by each section, summarizing the section current, and injecting summarized current into a main circuit to counteract original common mode total current so as to inhibit common mode interference.
2. The active electromagnetic interference filter of the multi-stage parallel connection type according to claim 1, wherein the main circuit includes an inverter and a line impedance stabilization network LISN connected in parallel to a dc side of the inverter; DC power supply generated by rectification circuitU DC The positive and negative two stages are connected to between the positive and negative electrodes of the LISN, the LISN is output to a three-phase full-bridge inverter, and the three-phase inverter inputs a series capacitor between the positive and negative electrodesC 1 、C 2 And the midpoint of the two capacitors is grounded to be used as a power supply neutral point O; three-phase full-bridge inversion comprises S a 、S b 、S c Three bridge arms, the inverter is driven to operate by using an SVPWM (space vector pulse width modulation) modulation mode, and the inverter outputs three-phase alternating current to pass through the equivalent common-mode impedance of the motorZ motor The output lines of three bridge arms of the inverter pass through three ground coupling capacitors respectivelyC p A ground wire is connected; wherein the motor equivalent common mode impedanceZ motor With three capacitors coupled to groundC p The parallel total impedance is the equivalent common mode total impedance of the systemZ LOAD 。
3. The active electromagnetic interference filter of claim 2, wherein the equivalent common mode impedance of the motor is the same as that of the active electromagnetic interference filter of the multi-stage parallel typeZ motor One phase of (1) includes a capacitorC m1 And is prepared byC m1 Series resistance-inductance loadRL 11 And is andRL 11 series resistance-inductance loadRL 12 And is andRL 11 parallel capacitorsC m11 And a resistorR 11 And is prepared byRL 12 Parallel capacitorsC m12 And a resistorR 12 ；
Structure and motor equivalent common mode impedanceZ motor One phase of equivalent impedance with the same structure and three phases of equivalent impedance are connected in parallel to form a complete equivalent common mode impedance of the motorZ motor ；
Equivalent common mode impedance of motorZ motor Wherein each single phase is respectively connected with the equivalent ground coupling capacitor of the three-phase line output by the inverter in parallelC p1 、C p2 、C p3 To form the equivalent common mode total impedance of the systemZ LOAD WhereinC p =C p1 =C p2 =C p3 。
4. The multi-stage parallel active EMI filter of claim 3 wherein the common mode voltage detection network module utilizes three equal resistance resistors connected in parallel to three phase lines of the full bridge inverter respectivelyR 0 And is andR 0 series connected resistorsR 1 、R 2 Collecting a common mode voltage detection value;
will the resistanceR 2 One end of the first resistor is grounded and the other end is connected to the operational amplifierOP 1 Positive input electrode of (2), operational amplifierOP 1 The negative input pole and the output pole are connected to form a voltage follower; operational amplifierOP 1 Connecting driving voltage ± -2V s 。
5. The active electromagnetic interference filter of claim 4, wherein the plurality of parallel inverse amplifier network modules comprise operational amplifiersOP 21 To an operational amplifierOP 2n (ii) a Amplifying resistorR 31 To amplifying resistanceR 3n ；
Operational amplifierOP 21 Negative inputEquivalent common mode impedance of pole connection systemZ LOAD The positive input electrode is grounded, and the output electrode is connected with an amplifying resistorR 31 Is connected with the negative input electrode; operational amplifierOP 21 Connecting driving voltage ± -2V s (ii) a Operational amplifierOP 22 To an operational amplifierOP 2n In the connection mode and the operational amplifierOP 21 The same, their amplification resistance values are respectively replaced byR 32 ToR 3n 。
6. The active electromagnetic interference filter of claim 5, wherein the compensation current injection module comprises a multi-stage push-pull circuit, a multi-stage output resistor and an isolation capacitor, and an input terminal of the first stage push-pull circuit is connected to the operational amplifier of the multi-stage parallel inverse amplification network moduleOP 21 The output end of the output resistor is connected with the output resistorR 41 ；
The connection mode of the rest multi-stage push-pull circuits is the same as that of the first-stage push-pull circuit, and the input ends of the rest multi-stage push-pull circuits are respectively connected with the operational amplifierOP 21 To an operational amplifierOP 2n The output ends of the two resistors are respectively connected with an output resistorR 42 ToR 4n (ii) a Will output resistance in multiple stagesR 41 ToR 4n The other end of the first capacitor is connected in parallel to a point to connect an isolation capacitorC 3 (ii) a Isolation capacitorC 3 The other end is grounded to form a complete compensation loop.
7. A control method of a multistage parallel active electromagnetic interference filter is characterized by comprising the following steps
When the main circuit is not connected with the improved AEFZ motor Total current to ground isI CM1 Capacitance viaC p Total current to ground isI CM2 The total current flowing into the LISN neutral point through the ground wire isI LISNs Is a system ofTotal common mode current ofI CM In whichI CM1 + I CM2 =I LISNs =I CM Forming a common mode interference conduction loop; wherein the content of the first and second substances,Z motor and three coupling capacitorsC p The parallel total impedance is the equivalent common mode total impedance of the systemZ LOAD Is provided withU CM /Z LOAD =I CM ；
When the improved AEF is connected into a main circuit, the common-mode voltage detection network module is used for extracting and reducing according to a certain proportion, and generating a waveform with the same form as the common-mode voltage as the input voltage of the improved AEF; the multistage parallel reverse amplification network module utilizes an operational amplifier to generate voltages required by compensation of each frequency band; the compensation current injection module applies the voltage generated by the multistage parallel reverse amplification network module to the output resistor to generate and collect compensation current required by each section, and the collected current is injected into the main circuit to be mutually offset with the original common-mode current so as to inhibit common-mode interference.
8. The method according to claim 7, wherein when the main circuit is connected to the improved AEF, the common mode voltage detection network module operates as follows: using three equal-resistance resistors respectively connected in parallel to three phase lines of full-bridge inverterR 0 And is andR 0 series connected resistorsR 1 、R 2 Collecting a common mode voltage detection value; will the resistanceR 2 Another end is grounded and connected to a resistorR 2 Upper partial pressure value ofV sense In whichkAs resistors in impedance networksR 2 The partial pressure proportion relation of (1) is as follows:
Figure 961953DEST_PATH_IMAGE001
(1)
will the resistanceR 2 Value of partial pressureV sense Input operational amplifierOP 1 Positive input electrode of, operational amplifierOP 1 The negative input pole and the output pole are connected to form a voltage follower; the voltage output value of the voltage follower is the voltage value of the input multistage parallel reverse amplification network moduleV IN Therein is provided withV IN =V sense =kU CM 。
9. The method for controlling the multistage parallel active electromagnetic interference filter according to claim 7, wherein when the main circuit is connected to the improved AEF, the operation process of the multistage parallel reverse amplification network module is as follows: operational amplifierOP 21 Equivalent common mode impedance of negative input pole connection systemZ LOAD Input ofV IN Voltage value, grounding the positive input electrode, passing the output electrode through an amplifying resistorR 31 Is connected with the negative input electrode; operational amplifierOP 21 Connecting driving voltage ± -2V s The output voltage value is the voltage value of the input compensation current injection moduleV OUT1 (ii) a Operational amplifierOP 22 To an operational amplifierOP 2n Connection mode and operational amplifierOP 21 The same, the amplification resistance values are respectively changed toR 32 ToR 3n The obtained output voltage values are respectivelyV OUT2 ToV OUTn (ii) a WhereinOP 21 ToOP 2n Respectively have gains ofA 1 ToA n ，n=1,2,3 …, having:
Figure 402162DEST_PATH_IMAGE002
(2)。
10. a multi-stage parallel connection as claimed in claim 7The control method of the active electromagnetic interference filter is characterized in that the working process of the compensating current injection module is as follows: operational amplifier in multi-stage parallel reverse amplification network moduleOP 21 Output voltage value ofV OUT1 The input is connected to the input end of the first stage push-pull circuit, and the output end of the first stage push-pull circuit is connected with the output resistorR 41 I.e. the value of the voltageV OUT1 Applied to the output resistorR 41 To obtain a compensation currentI COMP1 ；
The working process of the rest multi-stage push-pull circuit is the same as that of the first stage push-pull circuit, and the operational amplifier is usedOP 22 To an operational amplifierOP 2n Output voltage value ofV OUT2 ToV OUTn Respectively applied to the output resistorsR 42 To is thatR 4n Thereby obtaining a compensation currentI COMP2 ToI COMPn (ii) a Order ton=1,2,3 …, having:
Figure 799645DEST_PATH_IMAGE003
(3)
compensating current to be outputI COMP1 ToI COMPn An isolation capacitor is connected in series after being connected to one point in parallelC 3 Can obtain a current flowing through the isolation capacitorC 3 Total compensation current ofI COMP (ii) a WhereinPIs a constant value representing the improved AEF parallel series, and comprises:
Figure 90685DEST_PATH_IMAGE004
(4)
make the compensating currentI COMP Can cancel common mode current, need to makeI COMP =-I CM Then, there are:
Figure 231817DEST_PATH_IMAGE005
(5)
will output the compensating currentI COMP Connected to ground when there is a common mode interference conduction loop in the systemI CM1 +I CM2 +I COMP =I LISNs Wherein whenI COMP =-I CM =-(I CM1 +I CM2 ) When there isI LISNs =0; in this case, the detected common mode current on the LISN is reduced to suppress system common mode interference.
CN202211250247.XA 2022-10-13 2022-10-13 Multistage parallel active common mode interference filter and control method Pending CN115333502A (en)

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