CN117254704A - Grid-connected voltage type rectifier frequency division analog resistance control method under unbalanced power grid - Google Patents

Grid-connected voltage type rectifier frequency division analog resistance control method under unbalanced power grid Download PDF

Info

Publication number
CN117254704A
CN117254704A CN202311231999.6A CN202311231999A CN117254704A CN 117254704 A CN117254704 A CN 117254704A CN 202311231999 A CN202311231999 A CN 202311231999A CN 117254704 A CN117254704 A CN 117254704A
Authority
CN
China
Prior art keywords
voltage
direct
current
grid
rectifier
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN202311231999.6A
Other languages
Chinese (zh)
Other versions
CN117254704B (en
Inventor
林建亨
袁炜豪
刘厅
熊文静
刘永露
孙尧
粟梅
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Central South University
Original Assignee
Central South University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Central South University filed Critical Central South University
Priority to CN202311231999.6A priority Critical patent/CN117254704B/en
Priority claimed from CN202311231999.6A external-priority patent/CN117254704B/en
Publication of CN117254704A publication Critical patent/CN117254704A/en
Application granted granted Critical
Publication of CN117254704B publication Critical patent/CN117254704B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS 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
    • H02M7/00Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21Conversion of ac power input into dc 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
    • H02M7/217Conversion of ac power input into dc 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
    • H02M7/219Conversion of ac power input into dc 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 in a bridge configuration
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS 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
    • H02M1/00Details of apparatus for conversion
    • H02M1/0003Details of control, feedback or regulation circuits
    • H02M1/0038Circuits or arrangements for suppressing, e.g. by masking incorrect turn-on or turn-off signals, e.g. due to current spikes in current mode control
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS 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
    • H02M1/00Details of apparatus for conversion
    • H02M1/12Arrangements for reducing harmonics from ac input or output

Abstract

The control method of the frequency division analog resistor of the grid-connected voltage type rectifier under the unbalanced power grid comprises the steps of firstly, obtaining a power grid current signal and a direct current bus voltage signal under a two-phase static coordinate system. And secondly, according to the idea of frequency division control, respectively extracting a direct current component and a frequency doubling component of the direct current bus voltage based on a notch filter and a band-pass filter. Then, the direct-current voltage control ring is designed to regulate and control the direct-current component of the direct-current bus voltage, and the pulsating voltage control ring is designed to inhibit the frequency doubling component of the direct-current bus voltage caused by the unbalanced power grid. And finally, based on the idea of analog resistance control, calculating by utilizing the output of the two voltage controllers and the sampled power grid current signal, filtering by a band-pass filter to obtain a voltage reference at the alternating current side of the rectifier, and generating a pulse signal for controlling the switching tube of the rectifier to be conducted according to a carrier modulation method. The method is completely realized under a static coordinate system, and accurate line parameters, a power grid voltage sensor and a complex phase-locked loop algorithm are not needed.

Description

Grid-connected voltage type rectifier frequency division analog resistance control method under unbalanced power grid
Technical Field
The invention relates to the field of frequency division analog resistance control of rectifiers, in particular to a frequency division analog resistance control method of a grid-connected voltage type rectifier under an unbalanced power grid.
Background
Three-phase voltage type rectifiers have been widely used as interfaces for power grids and distributed generation systems, storage systems and transmission systems, due to advantages of controllability and flexibility. However, when connected to an unbalanced grid (unbalanced voltage amplitude, phase imbalance, asymmetric input impedance, etc.), the performance of the grid-tied voltage type rectifier will deteriorate dramatically, inducing dc bus voltage ripple and ac side third harmonic current at twice the grid frequency. Therefore, it is of great importance to study the high-performance control strategy of the three-phase grid-connected rectifier under the unbalanced grid voltage condition to reduce the negative influence of the unbalanced grid voltage. Control schemes under unbalanced power networks for voltage-type rectifiers have been proposed in great numbers, with sensorless control having received great attention due to cost savings and improved reliability. The most common approach is to design a grid voltage observer. The leberg state observer, kalman filter-based observer and virtual flux linkage-based observer have been widely studied and proved to be effective. But these methods all suffer from parameter uncertainty. In recent years, analog resistance control has become a very promising method for controlling grid-connected converters due to the characteristics of no sensor and easy implementation. Although the control thought is expanded to the three-phase voltage type rectifier under the unbalanced power network by the prior scholars, the control structure is complex, and certain implementation difficulty exists. Therefore, it is of great practical importance to develop a simple but effective sensorless control strategy.
Disclosure of Invention
In order to solve the technical problems, the invention provides a frequency division analog resistance control method of a grid-connected voltage type rectifier under an unbalanced power grid, which combines the idea of frequency division control with an analog resistance control technology to achieve the aims of constant direct current bus voltage and sine input current of a three-phase voltage type rectifier under the working condition of the unbalanced power grid.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
the frequency division analog resistance control method of the grid-connected voltage type rectifier under the unbalanced power grid comprises the following steps of:
s1, acquiring a current signal of an alternating current side and a voltage signal of a direct current side of a three-phase voltage type rectifier under a two-phase static coordinate system;
s2, respectively extracting a direct current component and a frequency doubling component of the direct current bus voltage based on a notch filter and a band-pass filter according to the idea of frequency division control;
s3, designing a direct-current voltage control loop to regulate and control direct-current components of the direct-current bus voltage, and designing a pulsating voltage control loop to inhibit double frequency components of the direct-current bus voltage caused by an unbalanced power grid;
and S4, based on the thought of analog resistance control, calculating by utilizing the output of the two voltage controllers and the sampled power grid current signal, filtering by a band-pass filter to obtain a voltage reference at the alternating current side of the rectifier, and generating a pulse signal for controlling the switching tube of the rectifier to be conducted according to a carrier modulation method.
As a further improvement of the present invention, the specific process of voltage division control in step S2 is as follows:
the sampled dc bus voltage signal is divided using a filter. The notch filter is used for extracting the DC bus voltage u dc The direct current component u of (2) dc0 The band-pass filter is used for extracting the frequency doubling component u of the direct current voltage dc2
Where s represents the Laplace operator, ω s Is the angular frequency, ζ and ζ of the power network 2 Respectively notch filter G Notch (s) and bandpass filter G BPF2 Damping factor of(s).
As a further improvement of the present invention, the specific processes of the dc voltage control loop and the pulsating voltage control loop in the step S3 are as follows:
DC component u of DC bus voltage dc0 And a DC voltage reference value u dc * Is used as the input of the direct voltage control loop proportional-integral PI controller to realize the direct current component u dc0 No static difference tracks the reference value, and the error of the frequency doubling component and the reference value 0 is used as the input of the pulse voltage ring proportion-resonance PR controller to restrain the frequency doubling pulse voltage.
The design of the direct current voltage control loop is as follows:
the design of the ripple voltage controller is as follows:
R e2 =PR(s)(0-u dc2 ) (4)
wherein,
k p0 ,k i0 respectively represent the proportional and integral gains, k of the PI controller p2 ,k r2 Respectively represent the proportional gain and resonance gain of the PR controller, R * Is a feed forward constant term greater than 0.
As a further development of the invention, the voltage reference calculation on the ac side of the rectifier described in S4 is specifically as follows:
s4.1 based on analog electricityThe idea of resistance control is to output R of two voltage controllers e0 、R e2 Sampling grid current signal i under two-phase stationary coordinate system α ,i β Multiplication to obtain i αβ R e0 And i αβ R e2 Will i αβ R e2 Screening out fundamental frequency components by a band-pass filter and then combining the fundamental frequency components with i αβ R e0 The difference is taken to obtain the voltage reference of the alternating current side of the rectifier, and the voltage reference u cαβ * The calculated expression of (2) is as follows:
wherein,
ζ 1 is G BPF1 A damping factor of(s);
band-pass filter G in the above BPF1 (s) center frequency of omega s For filtering out i αβ R e2 Third harmonic component of (a);
and S4.2, generating driving signals of six switching tubes of the rectifier by using a carrier modulation method according to the command voltage value of the alternating current side of the rectifier.
The innovation points of the invention are as follows:
1) The frequency division analog resistance control method of the grid-connected voltage type rectifier under the unbalanced power grid is completely realized based on a static coordinate system, a grid-side voltage sensor, accurate line parameters and a complex phase-locked loop algorithm are not needed, and the method has the advantages of simplicity in realization, low cost and strong robustness.
2) The control method only uses a Proportional Integral (PI) controller, a Proportional Resonance (PR) controller, a notch filter and three band-pass filters, so that direct-current bus voltage pulsation of the three-phase rectifier under an unbalanced power grid is simply and effectively restrained, and current harmonic waves at the grid side are reduced.
Drawings
FIG. 1 is a flowchart of the control algorithm of an embodiment of the present invention;
FIG. 2 is a block diagram of a control system according to an embodiment of the present invention;
FIG. 3 is a general control block diagram of a control method according to an embodiment of the present invention;
FIG. 4 is a waveform diagram of input voltage and input current of a simulation experiment power grid and a harmonic analysis diagram of a phase current at an input side by a frequency division simulation resistance control method of a grid-connected voltage type rectifier under an unbalanced power grid in an embodiment of the invention;
fig. 5 is a dynamic response diagram of a step change of a voltage of a direct current bus in a simulation experiment of a frequency division analog resistance control method of a grid-connected voltage type rectifier under an unbalanced power grid.
Detailed Description
The invention is described in further detail below with reference to the attached drawings and detailed description:
fig. 1 is a working flow chart of a frequency division simulation resistance control method of a grid-connected voltage type rectifier under an unbalanced power network. Fig. 2 is a block diagram of a control system of a frequency division analog resistance control method of a grid-connected voltage type rectifier under an unbalanced power supply of the present invention, in which a main circuit includes a voltage type rectifier 1 to be implemented according to the present invention; the control circuit part is a sampling circuit 2, a controller 3 and a driving circuit 4. The left sampling circuit of the sampling circuit 2 is responsible for sampling and conditioning the grid current, and the right sampling circuit is used for sampling the direct current bus voltage. The controller 3 is responsible for the operations such as modulation and control, and transmits the generated PWM switching pulse signal to the driving circuit 4 to control the operation of each switching tube.
FIG. 3 is a general control block diagram of a method for controlling a frequency-dividing analog resistor of a grid-connected voltage-type rectifier under an unbalanced power grid, collecting a grid current i abc And a DC bus voltage u dc And a trap is adopted to acquire the direct current component of the direct current bus voltage, and a band-pass filter is adopted to acquire the frequency component of the double power grid of the direct current bus voltage. According to the frequency division concept, the direct current bus voltage control loop is divided into a direct current voltage control loop and a pulsating voltage control loop. DC busThe error of the DC component of the voltage and the DC voltage reference value is used as the input of the DC voltage control loop PI controller, and the error of the frequency doubling component and the reference value 0 is used as the input of the pulse voltage loop PR controller. The output of the two controllers is multiplied by the grid current under the two-phase static coordinate system and then subtracted to obtain the voltage reference value u of the alternating current side under the two-phase static coordinate system of the rectifier * ,u *
Fig. 4 is a waveform diagram of an input side of a grid in a simulation experiment of a frequency division simulation resistance control method of a grid-connected voltage type rectifier under an unbalanced power grid, fig. 4 (a) is a waveform diagram of an unbalanced grid voltage simulation, three-phase voltages are in an unbalanced state, and the phase and amplitude of the grid voltage are asymmetric (u) sa =99V,u sb =88V,u sc =110V,). Fig. 4 (b) is a simulation waveform of the current of the power grid, fig. 4 (c) is harmonic analysis of the a-phase current of the power grid, and as can be seen from the graph, the input current of the power grid is basically sinusoidal, the total harmonic distortion rate of the a-phase input current is 3.33%, and the feasibility of the proposed control method is verified.
Fig. 5 is a waveform diagram of a given voltage step response in a simulation experiment of a frequency division simulation resistance control method of a grid-connected voltage type rectifier under an unbalanced power grid. Wherein the dc link voltage reference varies from 300V to 350V. The transient response is within 20ms, indicating that the proposed control has good dynamic performance.
The above description is only of the preferred embodiment of the present invention, and is not intended to limit the present invention in any other way, but is intended to cover any modifications or equivalent variations according to the technical spirit of the present invention, which fall within the scope of the present invention as defined by the appended claims.

Claims (4)

1. The frequency division analog resistance control method of the grid-connected voltage type rectifier under the unbalanced power grid comprises the following steps of:
s1, acquiring a current signal of an alternating current side and a voltage signal of a direct current side of a three-phase voltage type rectifier under a two-phase static coordinate system;
s2, respectively extracting a direct current component and a frequency doubling component of the direct current bus voltage based on a notch filter and a band-pass filter according to the idea of frequency division control;
s3, designing a direct-current voltage control loop to regulate and control direct-current components of the direct-current bus voltage, and designing a pulsating voltage control loop to inhibit double frequency components of the direct-current bus voltage caused by an unbalanced power grid;
and S4, based on the thought of analog resistance control, calculating by utilizing the output of the two voltage controllers and the sampled power grid current signal, filtering by a band-pass filter to obtain a voltage reference at the alternating current side of the rectifier, and generating a pulse signal for controlling the switching tube of the rectifier to be conducted according to a carrier modulation method.
2. The method for controlling the frequency division analog resistance of the grid-connected voltage type rectifier under the unbalanced power network according to claim 1, wherein the method comprises the following steps of:
the specific process of voltage frequency division control described in step S2 is as follows:
the sampled dc bus voltage signal is divided using a filter. The notch filter is used for extracting the DC bus voltage u dc The direct current component u of (2) dc0 The band-pass filter is used for extracting the frequency doubling component u of the direct current voltage dc2
Where s represents the Laplace operator, ω s Is the angular frequency, ζ and ζ of the power network 2 Respectively notch filter G Notch (s) and bandpass filter G BPF2 Damping factor of(s).
3. The method for controlling the frequency division analog resistance of the grid-connected voltage type rectifier under the unbalanced power network according to claim 1, wherein the method comprises the following steps of:
the specific processes of the direct-current voltage control loop and the pulsating voltage control loop in the step S3 are as follows:
DC component u of DC bus voltage dc0 And a DC voltage reference value u dc * Is used as the input of the direct voltage control loop proportional-integral PI controller to realize the direct current component u dc0 No static difference tracks the reference value, and the error of the frequency doubling component and the reference value 0 is used as the input of the pulse voltage ring proportion-resonance PR controller to restrain the frequency doubling pulse voltage.
The design of the direct current voltage control loop is as follows:
the design of the ripple voltage controller is as follows:
R e2 =PR(s)(0-u dc2 ) (4)
wherein,
k p0 ,k i0 respectively represent the proportional and integral gains, k of the PI controller p2 ,k r2 Respectively represent the proportional gain and resonance gain of the PR controller, R * Is a feed forward constant term greater than 0.
4. The method for controlling the frequency division analog resistance of the grid-connected voltage type rectifier under the unbalanced power network according to claim 1, wherein the method comprises the following steps of:
the voltage reference calculation on the ac side of the rectifier described in S4 is specifically as follows:
s4.1, based on the thought of analog resistance control, outputting R by two paths of voltage controllers e0 、R e2 Sampling grid current signal i under two-phase stationary coordinate system α ,i β Multiplication to obtain i αβ R e0 And i αβ R e2 Will i αβ R e2 Screening out fundamental frequency components by a band-pass filter and then combining the fundamental frequency components with i αβ R e0 The difference is taken to obtain the voltage reference of the alternating current side of the rectifier, and the voltage reference u cαβ * The calculated expression of (2) is as follows:
wherein,
ζ 1 is G BPF1 A damping factor of(s);
band-pass filter G in the above BPF1 (s) center frequency of omega s For filtering out i αβ R e2 Third harmonic component of (a);
and S4.2, generating driving signals of six switching tubes of the rectifier by using a carrier modulation method according to the command voltage value of the alternating current side of the rectifier.
CN202311231999.6A 2023-09-22 Grid-connected voltage type rectifier frequency division analog resistance control method under unbalanced power grid Active CN117254704B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202311231999.6A CN117254704B (en) 2023-09-22 Grid-connected voltage type rectifier frequency division analog resistance control method under unbalanced power grid

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202311231999.6A CN117254704B (en) 2023-09-22 Grid-connected voltage type rectifier frequency division analog resistance control method under unbalanced power grid

Publications (2)

Publication Number Publication Date
CN117254704A true CN117254704A (en) 2023-12-19
CN117254704B CN117254704B (en) 2024-04-19

Family

ID=

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101944853A (en) * 2010-03-19 2011-01-12 郁百超 Green power inverter
CN102891614A (en) * 2012-10-26 2013-01-23 河南师范大学 Improved dead-beat control method for pulse width modulation (PWM) rectifier at unbalance of voltage of power grid
WO2014107938A1 (en) * 2013-01-08 2014-07-17 广东志成冠军集团有限公司 Current source type rectifier and grid-connected control method based on virtual resistor
CN109802584A (en) * 2019-03-26 2019-05-24 大连理工大学 A kind of unitized MPC method of the three-phase VSR that achievable alternating current-direct current side performance is taken into account
CN111740455A (en) * 2020-07-22 2020-10-02 太原理工大学 Bus interface converter control method for uniformly compensating alternating-current unbalanced voltage and direct-current pulsating voltage
CN112350595A (en) * 2020-11-19 2021-02-09 中南大学 Analog impedance control method for inhibiting input unbalance influence of AC/DC matrix converter
CN114142751A (en) * 2021-12-06 2022-03-04 重庆理工大学 Three-phase CSR proportional-integral resonance control method under unbalanced grid voltage
CN115498696A (en) * 2022-10-24 2022-12-20 中南大学 Three-phase rectifier analog resistance control method for unbalanced power grid

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101944853A (en) * 2010-03-19 2011-01-12 郁百超 Green power inverter
CN102891614A (en) * 2012-10-26 2013-01-23 河南师范大学 Improved dead-beat control method for pulse width modulation (PWM) rectifier at unbalance of voltage of power grid
WO2014107938A1 (en) * 2013-01-08 2014-07-17 广东志成冠军集团有限公司 Current source type rectifier and grid-connected control method based on virtual resistor
CN109802584A (en) * 2019-03-26 2019-05-24 大连理工大学 A kind of unitized MPC method of the three-phase VSR that achievable alternating current-direct current side performance is taken into account
CN111740455A (en) * 2020-07-22 2020-10-02 太原理工大学 Bus interface converter control method for uniformly compensating alternating-current unbalanced voltage and direct-current pulsating voltage
CN112350595A (en) * 2020-11-19 2021-02-09 中南大学 Analog impedance control method for inhibiting input unbalance influence of AC/DC matrix converter
CN114142751A (en) * 2021-12-06 2022-03-04 重庆理工大学 Three-phase CSR proportional-integral resonance control method under unbalanced grid voltage
CN115498696A (en) * 2022-10-24 2022-12-20 中南大学 Three-phase rectifier analog resistance control method for unbalanced power grid

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
SHIMING XIE; YAO SUN; JIANHENG LIN: "Resistance-Emulating Control Strategy for Three-Phase Voltage Source Rectifiers Under Unbalanced Grids", IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, vol. 2022, no. 69, 25 February 2021 (2021-02-25), pages 2837 - 3841 *
谢宙桦;赵晨聪;黄万启;: "不平衡电压下基于RBF网络并网变流器的控制", 控制工程, no. 09, 20 September 2020 (2020-09-20) *

Similar Documents

Publication Publication Date Title
Song et al. Predictive current control of three-phase grid-connected converters with constant switching frequency for wind energy systems
CN103475029B (en) Three-phase LCL type grid-connected inverter control system and method based on pole assignment
CA2719584A1 (en) Dc bus voltage harmonics reduction
CN103904922A (en) Control method based on virtual flux linkage orientation and used for voltage-type rectifier
CN106357143A (en) Loop current inhibition method suitable for modular multilevel converter
WO2020204010A1 (en) Electric power converting device, and electricity generating system
CN102916596A (en) Input and output power resonance control method of PWM (pulse width modulation) rectifier under voltage unsymmetrical fault
Ahmad et al. A new simple structure PLL for both single and three phase applications
CN107863775B (en) Current control algorithm suitable for selective harmonic compensation of active power filter
CN105743367A (en) Dead beat control method of pulse width modulation (PWM) rectifier under unbalanced power grid voltage
CN112787491A (en) Input current harmonic suppression method of three-stage AC/DC power supply
JP5055184B2 (en) Power converter and its harmonic current suppression method
CN112636348B (en) Control method of modular three-phase current type grid-connected inverter
CN117254704B (en) Grid-connected voltage type rectifier frequency division analog resistance control method under unbalanced power grid
CN102916597B (en) PWM (pulse width modulation) rectifier input and output power compensation control method in voltage asymmetry
CN117254704A (en) Grid-connected voltage type rectifier frequency division analog resistance control method under unbalanced power grid
Kikuchi et al. Deadbeat control for Multi-level Inverter using 1MHz Multisampling Method for Utility Interactive System
CN114928076B (en) Double closed-loop control method of virtual synchronous machine without alternating-current voltage sensor
CN107742987A (en) A kind of phase sequence self-adaption control method of Three-Phase PWM Rectifier
CN107565564A (en) Active Power Filter-APF and its quick composite control method based on quick Repetitive controller
CN114301361B (en) Control method of electrolytic capacitor-free permanent magnet synchronous motor driving system based on bus current control
CN115800328A (en) Method, device and medium for controlling unbalance of three-phase four-leg full-bridge inverter
CN111525551B (en) Target control method and system for rectifier under unbalanced power grid voltage
CN112039123B (en) Control method for grid-connected inverter without alternating voltage sensor
CN111934575B (en) Output voltage balance control method and medium for train auxiliary converter

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant