CN115189557A - Method and device for suppressing second harmonic current of direct current transmission system - Google Patents
Method and device for suppressing second harmonic current of direct current transmission system Download PDFInfo
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- CN115189557A CN115189557A CN202210770246.1A CN202210770246A CN115189557A CN 115189557 A CN115189557 A CN 115189557A CN 202210770246 A CN202210770246 A CN 202210770246A CN 115189557 A CN115189557 A CN 115189557A
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- 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
- H02M1/14—Arrangements for reducing ripples from dc input or output
- H02M1/143—Arrangements for reducing ripples from dc input or output using compensating arrangements
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J1/00—Circuit arrangements for dc mains or dc distribution networks
- H02J1/02—Arrangements for reducing harmonics or ripples
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- 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
- H02M1/42—Circuits or arrangements for compensating for or adjusting power factor 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
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac 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
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac 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
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac 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 with automatic control of output voltage or current, e.g. switching regulators
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- 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
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
Abstract
The invention provides a method for suppressing second harmonic current of a direct current transmission system, which comprises the following steps: acquiring output voltage of an output side, and converting the output voltage to obtain converted voltage; sampling the converted voltage, comparing the sampled voltage with a reference voltage, and generating an error voltage amplification signal; attenuating a low-frequency pulsating component of the voltage frequency of the error voltage amplification signal, and taking the attenuated low-frequency pulsating component as a given signal; collecting a sampling signal of the filter inductance current, and generating a high-frequency pulse signal with a given signal; generating a driving signal by the high-frequency pulse signal, and regulating the output voltage by performing up-conversion or down-conversion; detecting a signal of second harmonic of the converted voltage; and generating a compensation voltage with the same magnitude and the opposite direction as the output low-frequency ripple on the load side according to the detected signal. The invention improves the quality of output voltage at the output side and achieves the purpose of reducing second harmonic current.
Description
Technical Field
The invention relates to the technical field of direct current transmission, in particular to a method and a device for suppressing second harmonic current of a direct current transmission system.
Background
Harmonic transmission phenomenon exists in a direct current transmission system based on a power grid commutation converter. The power frequency negative sequence harmonic voltage of a typical ac system will produce 2 times harmonic voltage on the dc side, and the harmonic current caused by the 2 times harmonic voltage on the dc side will produce 3 times positive sequence harmonic current and power frequency negative sequence harmonic current in the ac system, which will further produce harmonic current. In the prior art, if a Buck PFC circuit based on a Buck converter exists, a low-frequency pulse signal of input power current at the low-voltage side of the converter cannot be effectively inhibited, and the output power quality is influenced.
Disclosure of Invention
The present invention is directed to a method and an apparatus for suppressing second harmonic current in a dc power transmission system, so as to solve the problems in the background art.
In order to achieve the purpose, the invention provides the following technical scheme:
a second harmonic current suppression method of a direct current transmission system comprises the following steps:
acquiring output voltage of an output side, and converting the output voltage to obtain converted voltage;
sampling the converted voltage, comparing the sampled voltage with a reference voltage, and generating an error voltage amplification signal;
attenuating a low-frequency pulsating component of a voltage frequency of the error voltage amplification signal, and taking the attenuated low-frequency pulsating component as a given signal;
collecting a sampling signal of the filter inductance current, and generating a high-frequency pulse signal with a given signal;
generating a driving signal by the high-frequency pulse signal, and regulating the output voltage by performing up-conversion or down-conversion;
detecting a signal of a second harmonic of the converted voltage;
and generating a compensation voltage with the same magnitude and the opposite direction as the output low-frequency ripple on the load side according to the detected signal.
Preferably, the signal of the second harmonic of the converted voltage is detected, and then the detected signal is amplified in proportion.
Preferably, the converting the output voltage comprises a step-up conversion or a step-down conversion.
Preferably, a sampling signal of the filter inductance current is collected, and a PWM high-frequency pulse signal is generated by the sampling signal and the given signal.
In order to achieve the purpose, the invention also provides the following technical scheme:
a second harmonic current suppression apparatus for a direct current transmission system, comprising:
the DC-DC converter is used for acquiring output voltage of an output side and converting the output voltage to obtain converted voltage;
the voltage regulator is used for sampling the voltage of the converted voltage, comparing the voltage with a reference voltage and generating an error voltage amplification signal;
the resonance controller is connected with the voltage regulator and is used for attenuating the low-frequency pulsating component of the voltage frequency of the error voltage amplification signal and using the attenuated low-frequency pulsating component as a given signal;
the current regulator is connected with the resonance controller and is used for collecting a sampling signal of the filter inductance current,
the signal generator is connected with the current regulator and is used for generating a high-frequency pulse signal by the sampling signal and the given signal;
the logic and drive circuit is used for generating a drive signal from the high-frequency pulse signal and regulating the output voltage by up-conversion or down-conversion;
the ripple compensation and amplification unit is used for detecting a signal of a second harmonic of the converted voltage;
and the compensating transformer is used for generating a compensating voltage with the same magnitude and the opposite direction as the output low-frequency ripple on the load side according to the detected signal.
Preferably, the ripple compensation and amplification unit includes a coupling isolation amplifier and a band pass filter connected thereto.
Compared with the prior art, the invention has the beneficial effects that:
according to the invention, the resonance controller is arranged to greatly attenuate the low-frequency component in the output of the voltage regulator, so that the low-frequency pulsation of the input direct current is effectively inhibited, the precision of the output voltage is well improved, the ripple waves can be directly offset on the output side by adopting the ripple wave compensation and amplification unit, meanwhile, the input current still keeps a higher power factor, the quality of the output voltage is improved, and the purpose of reducing the second harmonic current is achieved.
Drawings
Fig. 1 is a schematic flow chart of a second harmonic current suppression method of a dc power transmission system according to the present invention;
FIG. 2 is a schematic diagram of a second harmonic current suppression apparatus of a DC transmission system according to the present invention;
fig. 3 is a block diagram of the ripple compensation and amplification unit according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example (b):
referring to fig. 1 to 3, the present invention provides a technical solution:
a second harmonic current suppression method of a direct current transmission system comprises the following steps:
acquiring output voltage of an output side, and converting the output voltage to obtain converted voltage;
sampling the converted voltage, comparing the sampled voltage with a reference voltage, and generating an error voltage amplification signal;
attenuating a low-frequency pulsating component of a voltage frequency of the error voltage amplification signal, and taking the attenuated low-frequency pulsating component as a given signal;
collecting a sampling signal of the filter inductance current, and generating a high-frequency pulse signal with a given signal;
generating a driving signal by the high-frequency pulse signal, and regulating the output voltage by up-conversion or down-conversion;
detecting a signal of second harmonic of the converted voltage;
and generating a compensation voltage with the same magnitude and the opposite direction as the output low-frequency ripple on the load side according to the detected signal.
Specifically, the signal of the second harmonic of the converted voltage is detected, and then the detected signal is amplified in proportion. Converting the output voltage includes either a step-up conversion or a step-down conversion. And collecting a sampling signal of the filter inductance current, and generating a PWM high-frequency pulse signal with a given signal.
In the present invention: the adopted suppression device comprises:
the DC-DC converter is used for acquiring output voltage of an output side and converting the output voltage to obtain converted voltage;
the voltage regulator is used for sampling the voltage of the converted voltage, comparing the voltage with a reference voltage and generating an error voltage amplification signal;
the resonance controller is connected with the voltage regulator and is used for attenuating the low-frequency pulsating component of the voltage frequency of the error voltage amplification signal and taking the attenuated low-frequency pulsating component as a given signal;
the current regulator is connected with the resonance controller and is used for collecting a sampling signal of the filter inductance current,
the signal generator is connected with the current regulator and is used for generating a high-frequency pulse signal by the sampling signal and the given signal;
the logic and drive circuit is used for generating a drive signal from the high-frequency pulse signal and regulating the output voltage by up-conversion or down-conversion;
the ripple compensation and amplification unit is used for detecting a signal of a second harmonic of the converted voltage;
and the compensation transformer is used for generating a compensation voltage with the same magnitude and the opposite direction as the output low-frequency ripple on the load side according to the detected signal.
Specifically, the ripple compensation and amplification unit comprises a coupling isolation amplifier and a band-pass filter connected with the coupling isolation amplifier.
In the circuit of FIG. 1, a DC-DC converter is connected to the output side (i.e., DC side), and the DC-DC converter outputs a voltage sampling signal U via a voltage regulator 0 And a reference voltage U ref The error voltage amplification signal generated after the comparison is used as the given signal I of the current loop (current regulator) ref The same-direction end of the input current regulator outputs a sampling signal I of the filter inductance current of the DC-DC converter Lf Into the reverse end of the current regulator. The current regulator outputs a modulation wave signal, the modulation wave signal and a carrier signal enter a Pulse Width Modulation (PWM) signal generator together to generate a (PWM) high-frequency pulse signal, and finally a DC-DC converter power tube driving signal is generated through a logic control and driving circuit. By connecting the resonant controller to the rear of the voltage regulator, the resonant controller is only on the inverter (rear stage output U) 0 I.e. the dotted line schematic part of fig. 1), the low-frequency ripple component in the output signal of the voltage loop (voltage regulator) is greatly attenuated after passing through the resonant controller, and the low-frequency component twice in the current given signal of the current regulator is filtered or greatly reduced so as to be suppressed.
In the present invention, as shown in the circuit of FIG. 1, the output side is connected via an inductor L f And an inductance L n The second harmonic in the output voltage is detected by the ripple compensation and amplification unit, the detected signal is amplified in proportion, and finally the signal is sent to the compensation transformer, so that the compensation transformer generates a compensation voltage U with the same size and the opposite direction as the output low-frequency ripple on the load side out The compensation voltage U out For accessing loads R 1 An output voltage is provided. The structure block diagram of the ripple compensation and amplification unit is shown in FIG. 3, the input end voltageSampling signal U 2 Through a resistance R 2 The divided voltage is taken and then fed to the input of the AD 204. The AD204 is a transformer coupling isolation amplifier, has the characteristics of small volume, low power consumption, good common mode performance, frequency bandwidth and the like, a band-pass filter which is formed by MAX26 and takes power frequency 50Hz as central frequency, an external clock signal generator 4047 chip is selected, the frequency is easy to adjust, and after the ratio is set through parameters, the adjustment is equal to the indirect adjustment of f, so that the fine adjustment of the phase position is facilitated. Then obtaining continuous smooth 50Hz fundamental wave signal through 1-order RC active low-pass filter circuit, adding proportion adjusting circuit composed of operational amplifier for matching amplitude, subtracting the adjusted signal and continuous smooth fundamental wave signal to obtain harmonic voltage signal U 1 . The fundamental wave signal and the fundamental wave signal in the measured signal are in the same phase, namely undistorted U is obtained 1 . By connecting a compensation transformer behind the ripple compensation and amplification unit, a compensation voltage U with the same magnitude and the opposite direction of the output low-frequency ripple is generated on the load side by the compensation transformer out The compensation voltage U out For accessing loads R 1 Providing an output voltage.
According to the invention, the resonance controller is arranged to greatly attenuate the low-frequency component in the output of the voltage regulator, so that the low-frequency pulsation of the input direct current is effectively inhibited, the precision of the output voltage is well improved, the ripple can be directly counteracted on the output side by adopting the ripple compensation and amplification unit, meanwhile, the input current still maintains a higher power factor, the quality of the output voltage is improved, and the purpose of reducing the second harmonic current is achieved.
The remaining parts of the invention, which are not described, may be the same as, or well known or may be implemented using the prior art, and will not be described in detail herein.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (6)
1. A method for suppressing a second harmonic current of a DC power transmission system, comprising:
acquiring output voltage of an output side, and converting the output voltage to obtain converted voltage;
sampling the converted voltage, comparing the sampled voltage with a reference voltage, and generating an error voltage amplification signal;
attenuating a low-frequency pulsating component of a voltage frequency of the error voltage amplification signal, and taking the attenuated low-frequency pulsating component as a given signal;
collecting a sampling signal of the filter inductance current, and generating a high-frequency pulse signal with a given signal;
generating a driving signal by the high-frequency pulse signal, and regulating the output voltage by performing up-conversion or down-conversion;
detecting a signal of a second harmonic of the converted voltage;
and generating a compensation voltage with the same magnitude and the opposite direction as the output low-frequency ripple on the load side according to the detected signal.
2. The method according to claim 1, wherein the signal of the second harmonic of the converted voltage is detected and then the detected signal is scaled up.
3. The method of claim 1, wherein converting the output voltage comprises step-up converting or step-down converting.
4. The method according to claim 1, wherein a sampled signal of the filtered inductor current is collected, and a PWM high frequency pulse signal is generated from the sampled signal and the given signal.
5. A second harmonic current suppression device for a dc power transmission system, comprising:
the DC-DC converter is used for acquiring output voltage of an output side and converting the output voltage to obtain converted voltage;
the voltage regulator is used for sampling the voltage of the converted voltage, comparing the voltage with a reference voltage and generating an error voltage amplification signal;
the resonance controller is connected with the voltage regulator and is used for attenuating the low-frequency pulsating component of the voltage frequency of the error voltage amplification signal and taking the attenuated low-frequency pulsating component as a given signal;
the current regulator is connected with the resonance controller and is used for collecting a sampling signal of the filter inductance current,
the signal generator is connected with the current regulator and is used for generating a high-frequency pulse signal by the sampling signal and the given signal;
the logic and drive circuit is used for generating a drive signal from the high-frequency pulse signal and regulating the output voltage by up-conversion or down-conversion;
the ripple compensation and amplification unit is used for detecting a signal of a second harmonic of the converted voltage;
and the compensation transformer is used for generating a compensation voltage with the same magnitude and the opposite direction as the output low-frequency ripple on the load side according to the detected signal.
6. The apparatus according to claim 5, wherein the ripple compensation and amplification unit comprises a coupled isolation amplifier and a band pass filter connected thereto.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210770246.1A CN115189557A (en) | 2022-06-30 | 2022-06-30 | Method and device for suppressing second harmonic current of direct current transmission system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210770246.1A CN115189557A (en) | 2022-06-30 | 2022-06-30 | Method and device for suppressing second harmonic current of direct current transmission system |
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| CN115189557A true CN115189557A (en) | 2022-10-14 |
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| CN202210770246.1A Pending CN115189557A (en) | 2022-06-30 | 2022-06-30 | Method and device for suppressing second harmonic current of direct current transmission system |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000037072A (en) * | 1998-07-17 | 2000-02-02 | Toshiba Corp | Power converting circuit |
| CN101877549A (en) * | 2010-06-08 | 2010-11-03 | 南京航空航天大学 | Method for inhibiting two-stage type orthogonal inverter input current low-frequency impulse |
| CN103199530A (en) * | 2012-01-05 | 2013-07-10 | 上海韦欧韦滤波设备有限公司 | Active power filter with method for processing harmonic waves in energy-saving and consumption-reducing mode |
| WO2014032369A1 (en) * | 2012-08-30 | 2014-03-06 | 东南大学 | Single-inductor dual-output switch power supply based on ripple control |
| CN210007392U (en) * | 2019-04-23 | 2020-01-31 | 广西电网有限责任公司电力科学研究院 | novel series active filters based on silicon carbide |
-
2022
- 2022-06-30 CN CN202210770246.1A patent/CN115189557A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000037072A (en) * | 1998-07-17 | 2000-02-02 | Toshiba Corp | Power converting circuit |
| CN101877549A (en) * | 2010-06-08 | 2010-11-03 | 南京航空航天大学 | Method for inhibiting two-stage type orthogonal inverter input current low-frequency impulse |
| CN103199530A (en) * | 2012-01-05 | 2013-07-10 | 上海韦欧韦滤波设备有限公司 | Active power filter with method for processing harmonic waves in energy-saving and consumption-reducing mode |
| WO2014032369A1 (en) * | 2012-08-30 | 2014-03-06 | 东南大学 | Single-inductor dual-output switch power supply based on ripple control |
| CN210007392U (en) * | 2019-04-23 | 2020-01-31 | 广西电网有限责任公司电力科学研究院 | novel series active filters based on silicon carbide |
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