CN110445406B - Dual-mode smooth transition control method of PWM rectifier - Google Patents

Dual-mode smooth transition control method of PWM rectifier Download PDF

Info

Publication number
CN110445406B
CN110445406B CN201910632631.8A CN201910632631A CN110445406B CN 110445406 B CN110445406 B CN 110445406B CN 201910632631 A CN201910632631 A CN 201910632631A CN 110445406 B CN110445406 B CN 110445406B
Authority
CN
China
Prior art keywords
modulation ratio
axis
soft start
pwm rectifier
controller
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.)
Active
Application number
CN201910632631.8A
Other languages
Chinese (zh)
Other versions
CN110445406A (en
Inventor
郑丽君
吕世轩
李长辉
耿蒲龙
高云广
田慕琴
宋建成
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.)
Taiyuan University of Technology
Original Assignee
Taiyuan University of Technology
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 Taiyuan University of Technology filed Critical Taiyuan University of Technology
Priority to CN201910632631.8A priority Critical patent/CN110445406B/en
Publication of CN110445406A publication Critical patent/CN110445406A/en
Application granted granted Critical
Publication of CN110445406B publication Critical patent/CN110445406B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • H02M1/36—Means for starting or stopping converters
    • 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
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12—Conversion 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
    • H02M7/21—Conversion 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
    • H02M7/217—Conversion 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
    • H02M7/219—Conversion 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
    • 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
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0038—Circuits 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

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Rectifiers (AREA)

Abstract

The invention discloses aA modulation ratio soft start controller is additionally arranged between a double closed-loop controller of a PWM rectifier and a PWM pulse signal generation module, the modulation ratio when the PWM rectifier is started is gradually reduced to a steady state value from large to small through the modulation ratio soft start controller, and then starting impact current of the PWM rectifier is restrainedk= 0; at the moment of start-upt 0To the end of the startt 1The mathematical model of the modulation ratio soft start controller isk=k 2‑k 1 tAfter the modulation ratio soft start is finished, the mathematical model of the modulation ratio soft start controller becomesk= 1; the PWM rectifier is started in a segmented mode through the modulation ratio soft start controller, so that the impact current generated at the starting moment of the PWM rectifier is completely eliminated, and the purpose of smooth transition is achieved.

Description

Dual-mode smooth transition control method of PWM rectifier
Technical Field
The invention relates to a control method of a three-phase voltage PWM rectifier, in particular to a safety control method of the PWM rectifier without current impact.
Background
When the PWM rectifier is started, the charging and discharging time of the filter inductor at the alternating current side is controlled to supply power to the direct current side mainly through the on and off of the bridge arm IGBT, so that the three-phase PWM rectifier can be divided into two types from the state of the filter inductor, wherein one type is inductor charging and energy accumulation; the other is that the inductor discharges to charge the direct current side, and when the charging time and the discharging time reach balance, the voltage of the direct current side is stable; when the PWM rectifier is started, if the initial modulation ratio amplitude is small, the time of the first circuit state is too long, the inductor is approximately connected between two phase power supplies on the alternating current side at the moment, the current increase rate is high, and large impact current influences the service life and safety of the system.
Common starting inrush current suppression methods include: the clipping method, as disclosed in publication No.: CN 104734481A; the target voltage value parabola rule starting method comprises the following steps: CN 103904873A; the vector type soft start method comprises the following steps: CN107196496A, and a parabolic superimposed ramp function starting method, as disclosed by the publication: CN105915039A, according to the formula
Figure RE-107109DEST_PATH_IMAGE001
The common point of these methods is that the output value of the voltage outer loop PI regulator, i.e. the reference value of the current inner loop d-axis is reducedi d *When the actual current increases more than the reference valuei d *When the temperature of the water is higher than the set temperature,m dthe current of the actual system is larger than the rated current, namely the suppression effect is generated after the generation of the impact current, so that the impact current caused by the undersize modulation ratio at the beginning of starting cannot be suppressed.
Disclosure of Invention
In order to improve the defects of the existing control method, the invention provides a dual-mode smooth transition control method of a PWM rectifier, which is characterized in that a modulation ratio soft start controller is added between a dual closed-loop controller and a PWM pulse signal generation module of the PWM rectifier, the modulation ratio soft start controller is used for changing the modulation ratio when the starting impact current of the PWM rectifier is not generated, and further changing a switch mode to achieve the purpose of inhibiting the impact current, and the specific technical scheme is as follows:
a dual-mode smooth transition control method of a PWM rectifier is characterized in that: the dual-mode smooth transition control method is characterized in that a modulation ratio soft start controller is additionally arranged between a dual closed-loop controller of a PWM rectifier and a PWM pulse signal generation module; the double closed-loop controller is used for controlling the voltage stability of the direct current side of the PWM rectifier; the modulation ratio soft start controller is used for amplifying the modulation ratio of the PWM rectifier during starting and inhibiting starting impact current; the PWM pulse generation module is used for generating a PWM pulse signal to control the switch to be conducted.
In the above technical scheme: the PWM rectifier is firstly calculated by a double closed-loop controller to obtain a three-phase modulation ratio when being startedm a 、m b、 m c (ii) a Then will bem a 、m b、 m c Inputting the modulation ratio soft start controller to calculate a new three-phase modulation ratiom a *、m b * 、 m c And outputting a switching signal by the PWM pulse signal generation module to control the PWM rectifier to start working.
The further technical scheme is as follows: the design process of the PWM rectifier double closed-loop controller and the modulation ratio soft start controller during starting is as follows:
(1) establishing a controller mathematical model of the rectifier under a dq coordinate system as follows:
Figure RE-51931DEST_PATH_IMAGE002
wherein:K vP ,K vI ,K iP ,K iI the proportional coefficient and the integral coefficient of the voltage outer ring and the current inner ring are respectively;v dc *is a reference value for the dc bus voltage;i d *，i d *given values for the d-axis and q-axis of the current loop respectively,i d ，i q the components of the actual net side current in the d-axis and q-axis respectively,ωis the fundamental angular frequency of the grid-side voltage,i cd ，i cq the components of the capacitor current in the d-axis and q-axis are filtered separately,L T is an AC side inductor (L T =L 1+L 2）；
(2) And (3) calculating to obtain a three-phase modulation ratio according to the d-axis component and the q-axis component of the modulation ratio obtained in the step (1), wherein the calculation formula is as follows:
Figure RE-DEST_PATH_IMAGE003
wherein:m a,m b,m cthe three-phase modulation ratio is adopted,C r s2/3a transformation matrix from a three-phase static coordinate system to a two-phase rotating coordinate system;
(3) inputting the three-phase modulation ratio in the step (2) into a modulation ratio soft start controller to obtain a new modulation ratio expression as follows:
Figure RE-138836DEST_PATH_IMAGE004
wherein:m a *、m b *、m c *the modulation ratio is output by the modulation ratio soft start controller;
(4) according to the three-phase modulation ratio output by the modulation ratio soft start controllerm a *、m b * 、 m c And controlling the PWM rectifier to conduct and work.
The further technical scheme is as follows: mathematical model of modulation ratio soft start controller at startkThe following were used:
Figure RE-DEST_PATH_IMAGE005
function(s)kIn the expression:
Figure RE-533914DEST_PATH_IMAGE006
v trmis a triangular carrierAmplitude, TsIs a period of a triangular carrier wave,ωis the fundamental angular frequency of the grid-side voltage,t 1in order to modulate the end time softer than the soft start time,t 0for the moment of start-up of the PWM rectifier,e d is the d-axis transformation component of the three-phase modulation ratio,v dc is the dc side voltage.
Wherein: the soft start controller of the modulation ratio when the PWM rectifier is started is a reverse slope function with a linear rule decreasing to 1.
Compared with the existing voltage soft start technology, the dual-mode smooth transition control method of the PWM rectifier provided by the invention is additionally provided with the modulation ratio soft start controller, the charging time of the inductor can be gradually increased when the PWM rectifier is controllably started by amplifying the modulation ratio, and the generation of impact current is inhibited.
Drawings
FIG. 1 is a main circuit and control diagram of a PWM rectifier according to the present invention.
Fig. 2 is a graph of a mathematical model of a modulation ratio soft start controller of the present invention.
Fig. 3 is an experimental waveform for a direct start PWM rectifier of the present invention.
Fig. 4 is a PWM rectifier voltage reference ramp soft start test waveform of the present invention.
Fig. 5 is a waveform of a PWM rectifier soft start experiment based on modulation ratio according to the present invention.
Detailed Description
The following further describes the embodiments of the present invention.
Implementing a method for controlling a bimodal smooth transition of a PWM rectifier, said bimodal smooth transition control
The preparation method comprises the following steps:
the first step is as follows: when the PWM rectifier is started, the three-phase modulation ratio is obtained by calculating through the double closed-loop controllerm a 、m b、 m c ；
The second step is that: at the time of start-upt 0-t 1In the interior of said container body,m a 、m b、 m c the input modulation ratio soft start controller calculates to obtain a new three-phase modulation ratiom a *、m b * 、 m c *；
The third step: according to the new three-phase modulation ratiom a *、m b * 、 m c *And the PWM pulse signal generating module outputs a pulse signal to control the work of the PWM rectifier.
The first step specifically comprises the following steps: firstly, uncontrolled rectification is carried out by diodes on a three-phase bridge arm to complete the pre-charging process of a direct current side capacitor, then the amplitude and the frequency of alternating current voltage and whether the alternating current side current and the direct current side voltage are in a normal value range are detected, after the detection is finished, network side voltage and current signals are collected, the alternating current component is converted into a direct current component under a dq coordinate system, voltage and current double closed loop, network voltage feedforward calculation and current inner loop decoupling calculation are finished to obtain modulation ratio d-axis and q-axis components, and a three-phase modulation ratio is obtained through coordinate transformationm a 、m b、 m c 。
The second step comprises the following specific contents: let the three-phase modulation ratio obtained in the first stepm a 、m b、 m c Inputting the three-phase modulation ratio into a modulation ratio soft start controller to obtain a new three-phase modulation ratio
Figure RE-DEST_PATH_IMAGE007
Coefficient of proportionalitykExpression (c):
Figure RE-706269DEST_PATH_IMAGE008
function(s)kIn the expression:
Figure RE-537607DEST_PATH_IMAGE009
m 0the calculation formula of (2) is as follows:
Figure RE-744597DEST_PATH_IMAGE010
v trmis the amplitude of the triangular carrier wave, TsIs a period of a triangular carrier wave,ωis the fundamental angular frequency of the grid-side voltage,t 1in order to modulate the end time softer than the soft start time,t 0for the moment of start-up of the PWM rectifier,e d is a d-axis transformation component of the three-phase voltage on the grid side,v dc is the dc side voltage.
The third step comprises the following specific contents: and (4) generating a switching signal of a three-phase bridge arm by using the three-phase modulation ratio obtained in the second step according to the SPWM principle, and controlling the PWM rectifier to work.
Detailed description of the preferred embodiment 1
The embodiment of the invention is described with reference to fig. 1 and fig. 2, in which fig. 1 is a main circuit and a control diagram of a PWM rectifier, v dc is a direct-current voltage, and the voltage is,S ap、S an、S bp、S bn、S cp、S cnis six IGBT switching tubes of a three-phase rectifier,e a、e b、e cthe voltage of the power grid is used as the voltage of the power grid,L 1、L 2、C 1is the network side inductor, the inverter side inductor and the filter capacitor of the LCL filter, R1 R2The parasitic resistance of the inductor is reduced,i dcthe current is input for the direct current power supply,i ga、i gb、i gcis the current on the network side and is,i La、i Lb、i Lcis the current of the side of the bridge arm, Cthe capacitor is a direct current side capacitor, and R is a direct current side load; the specific embodiment of the invention describes a dual-mode smooth transition control method of a PWM rectifier, the PWM rectifier is started by mainly controlling the amplitude of a three-phase modulation ratio so as to gradually increase the charging time of a filter inductor at an alternating current side and achieve the purpose of a three-phase PWM rectifierThe purpose of starting without impact current comprises the following specific steps:
the first step is as follows: firstly, uncontrolled rectification is carried out by diodes on a three-phase bridge arm to complete the pre-charging of a direct current side capacitor.
The second step is that: and detecting the amplitude and frequency of the alternating current voltage and whether the alternating current side current and the direct current side voltage are in a normal value range, acquiring network side voltage, filter capacitor current and current signals after detection is finished, and converting the alternating current component into a direct current component under a dq coordinate system.
The third step: the given value of the DC-side voltage is slowly increased according to the function curve 1 shown in FIG. 1v dc *The d-axis q-axis component of the three-phase modulation ratio is calculated according to the following formulam d 、m q ；
Figure RE-248260DEST_PATH_IMAGE011
。
The fourth step: according to
Figure RE-173491DEST_PATH_IMAGE012
Obtaining three-phase modulation ratiom a 、m b、 m c 。
The fifth step: let the three-phase modulation ratio obtained in the fourth stepm a 、m b、 m c The input modulation ratio soft start controller obtains a new three-phase modulation ratiom a *、m b * 、 m c And controlling the PWM rectifier to conduct and work.
The mathematical model of the soft start controller for the modulation ratio at the starting moment is a piecewise function formed by splicing an inverse slope function and a constant functionkThe function of (a) is expressed as follows:
Figure RE-460115DEST_PATH_IMAGE013
function(s)kIn the expression:
Figure RE-583929DEST_PATH_IMAGE014
m 0the calculation formula of (2) is as follows:
Figure RE-868280DEST_PATH_IMAGE015
in the formula:v trmis the amplitude of the triangular carrier wave, TsIs a triangular carrier period, omega is the angular frequency of the fundamental wave of the voltage on the network side, t1For a softer than soft start end time of modulation, t0For the moment of start-up of the PWM rectifier,e dis a d-axis transformation component of the three-phase voltage on the grid side,v dcis the dc side voltage.
And a sixth step: and calculating the three-phase modulation ratio obtained in the fifth step by using an SPWM principle to obtain a switching signal of a three-phase bridge arm, and controlling the PWM rectifier to work.
The embodiment amplifies the modulation ratio of the PWM rectifier during starting, and further avoids the impulse current generated when the PWM rectifier is transited from an uncontrollable state to a controllable state.

Claims (1)

1. A dual-mode smooth transition control method of a PWM rectifier is characterized in that: the starting process of the PWM rectifier is controlled by a double closed-loop controller and a modulation ratio soft start controller together, and the design process of the double closed-loop controller and the modulation ratio soft start controller is as follows:
(1) establishing a mathematical model of the double closed-loop controller of the rectifier under the dq coordinate system as follows:
Figure DEST_PATH_IMAGE001
wherein:K vP ,K vI ,K iP ,K iI the proportional coefficient and the integral coefficient of the voltage outer ring and the current inner ring are respectively;v dc *is a reference value for the dc bus voltage;v dc is the actual dc bus voltage value of the rectifier;m d ，m q the components of the modulation ratio generated by the double closed-loop controller on the d-axis and the q-axis respectively;e d ，e q the components of the three-phase voltage on the grid side on the d axis and the q axis are respectively;k 0is the active damping coefficient of the double closed-loop controller;i d *，i q *respectively setting values of d axis and q axis of the current loop;i d ，i q the components of the actual grid side current in the d-axis and q-axis, respectively;ωis the grid side voltage fundamental angular frequency;i cd ，i cq the components of the filter capacitor current of the LCL filter at the input side of the rectifier on the d axis and the q axis respectively;L T is an equivalent inductance of the alternating current side, L T =L 1+L 2；L 1，L 2the filter inductor is arranged on the side, close to the power grid, of the LCL filter of the rectifier and the filter inductor is arranged on the side close to the switching device;
(2) and (3) calculating to obtain a three-phase modulation ratio according to the d-axis component and the q-axis component of the modulation ratio obtained in the step (1), wherein the calculation formula is as follows:
Figure 470144DEST_PATH_IMAGE002
wherein:m a,m b,m cthe three-phase modulation ratio is adopted,C r s2/3a transformation matrix from a two-phase rotating coordinate system to a three-phase static coordinate system;
(3) inputting the three-phase modulation ratio in the step (2) into a modulation ratio soft start controller to obtain a new modulation ratio, wherein the calculation formula is as follows:
Figure DEST_PATH_IMAGE003
wherein:m a *、m b *、m c *the modulation ratio is output by the modulation ratio soft start controller;
(4) according to the three-phase modulation ratio output by the modulation ratio soft start controllerm a *、m b *、m c *Controlling the PWM rectifier to conduct and work;
(5) wherein: mathematical model of modulation ratio soft start controller at startkThe following were used:
Figure 268336DEST_PATH_IMAGE004
function(s)kIn the expression:
Figure DEST_PATH_IMAGE005
v trmis the amplitude of the triangular carrier wave, TsIs a period of a triangular carrier wave,ωis the fundamental angular frequency of the grid-side voltage,t 1in order to modulate the end time softer than the soft start time,t 0for the moment of start-up of the PWM rectifier,e d is a d-axis transformation component of the three-phase voltage on the grid side,v dc is a direct current side voltage;
(6) wherein: the mathematical model k of the modulation ratio soft start controller when the PWM rectifier is started is a reverse slope function with a linear rule decreasing to 1.
CN201910632631.8A 2019-07-14 2019-07-14 Dual-mode smooth transition control method of PWM rectifier Active CN110445406B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201910632631.8A CN110445406B (en) 2019-07-14 2019-07-14 Dual-mode smooth transition control method of PWM rectifier

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201910632631.8A CN110445406B (en) 2019-07-14 2019-07-14 Dual-mode smooth transition control method of PWM rectifier

Publications (2)

Publication Number Publication Date
CN110445406A CN110445406A (en) 2019-11-12
CN110445406B true CN110445406B (en) 2021-10-26

Family

ID=68430431

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201910632631.8A Active CN110445406B (en) 2019-07-14 2019-07-14 Dual-mode smooth transition control method of PWM rectifier

Country Status (1)

Country Link
CN (1) CN110445406B (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112910283B (en) * 2021-03-09 2022-03-22 山东建筑大学 Method and system for simultaneously restraining common-mode voltage and circulating current of modular parallel rectifier
CN116365855B (en) * 2023-01-07 2023-10-10 安徽大学 Starting control method for three-phase voltage type PWM rectifier

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101783597A (en) * 2010-03-31 2010-07-21 山东新风光电子科技发展有限公司 Dynamic reactive compensation device based on direct current side active structure and amplitude adjustment control
CN103855717A (en) * 2014-03-27 2014-06-11 安徽工业大学 Pulse-free soft starting method of low-voltage SVG (static var generator)

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101783597A (en) * 2010-03-31 2010-07-21 山东新风光电子科技发展有限公司 Dynamic reactive compensation device based on direct current side active structure and amplitude adjustment control
CN103855717A (en) * 2014-03-27 2014-06-11 安徽工业大学 Pulse-free soft starting method of low-voltage SVG (static var generator)

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
单相PWM整流器启动控制策略分析;刘龙等;《变频器世界》;20151031;第34-37页 *

Also Published As

Publication number Publication date
CN110445406A (en) 2019-11-12

Similar Documents

Publication Publication Date Title
US9257931B2 (en) Power conversion apparatus
JP5212491B2 (en) Power converter
CN106026072B (en) double-PWM converter direct-current bus voltage fluctuation suppression method and control method
WO2015165191A1 (en) Steady state control method for three-phase double-mode inverter
JP5435464B2 (en) Motor starting method
US9871462B2 (en) Regenerative variable frequency drive with auxiliary power supply
CN105429484B (en) PWM rectifier prediction power control method and system based on any period delay
CN103944428B (en) A kind of control method of the Three-Phase PWM Rectifier being applicable to waveform distortion of the power supply network
JP5829053B2 (en) Grid-connected inverter device
CN101702583B (en) Method for controlling direct-drive wind power generation convertor
CN110445406B (en) Dual-mode smooth transition control method of PWM rectifier
CN113346559B (en) Low-voltage ride-through power switching control method for direct-drive wind power system under extremely weak grid
SG175197A1 (en) Method of controlling power conversion device
JP6750508B2 (en) Power converter and harmonic suppression method thereof
CN109004849B (en) PWM rectifier fast response control method for electric servo loading system
CN115995813B (en) Grid-connected inverter oscillation suppression strategy based on hybrid damping
JP6265345B2 (en) Speed sensorless motor control apparatus and speed sensorless motor starting method
CN103427694B (en) A kind of three-phase five-level converter electric capacity potential balance control method and system
JP4017113B2 (en) Active filter for power distribution system
CN110365038B (en) Microgrid inverter and control method and control device thereof
CN110365039B (en) Microgrid inverter and control method and control device thereof
Qiu et al. High performance current source inverter fed induction motor drive with minimal harmonic distortion
CN108599600A (en) Single-phase rectifier double -loop control calculation method of parameters and computing system
CN108667322A (en) single-phase rectifier control method and system
WO2018185963A1 (en) Power conversion device and control method thereof

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
GR01 Patent grant