CN101834443A - Method for balancing three-level direct current midpoint voltage by using time factor - Google Patents
Method for balancing three-level direct current midpoint voltage by using time factor Download PDFInfo
- Publication number
- CN101834443A CN101834443A CN201010155539A CN201010155539A CN101834443A CN 101834443 A CN101834443 A CN 101834443A CN 201010155539 A CN201010155539 A CN 201010155539A CN 201010155539 A CN201010155539 A CN 201010155539A CN 101834443 A CN101834443 A CN 101834443A
- Authority
- CN
- China
- Prior art keywords
- mid
- voltage
- time
- point voltage
- zero
- 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
Links
Images
Classifications
-
- 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
Abstract
The invention discloses a method for balancing a three-level direct current midpoint voltage by using a time factor, which comprises the following steps of: 1, sampling a midpoint voltage and a midpoint current, and judging the midpoint voltage and the midpoint current; 2, executing a step 3 when the midpoint voltage is not zero, and jumping to a step 5 when the midpoint voltage is zero; 3, determining acting time of positive and negative small vectors according to the directions of the midpoint voltage and the midpoint current; 4, balancing the midpoint voltage after the positive and negative small vectors are counteracted; and 5, finishing the program. The value range of the time factor is experimental data and is adjusted according to the voltage value and the current value detected by an active filter and the running directions of the voltage and the current. The method has the advantages of prolonging service life of the capacitor, along with simple and convenient operation, low voltage fluctuation on a direct-current side capacitor, few sampling data and low requirement on software and hardware.
Description
Technical field
The present invention relates to a kind of balance method that is applied to Active Power Filter-APF three level system, particularly relate to a kind of method of utilizing time factor balancing three-level direct current mid-point voltage.
Background technology:
Three level voltage equilibrium problems of the DC side of Active Power Filter-APF are one of key technologies of active filter.When the mid point of active electric-power filter DC side is uneven, to bring following harm: the first, the current transformer output voltage waveforms distorts, the harmonic compensation current that is input in the electrical network just has low-order harmonic, thereby makes Active Power Filter-APF can not follow the tracks of the harmonic current of load well; The second, the voltage that bears of switching device is unbalanced, every mutually in a part of device to bear voltage higher, will influence operate as normal when serious; Three, the voltage fluctuation on the dc bus capacitor has reduced the life-span of electric capacity.
In order to make the Active Power Filter-APF can operate as normal, should make great efforts to make mid-point voltage to keep balance.Especially when design current transformer control strategy, to consider the influence of vector alignment voltage, the fluctuation of mid-point voltage is dropped to minimum degree.The method of prior art control neutral point voltage balance mainly contains: one, open loop control, by the positive and negative small vector of alternate selection, do not need to detect DC bus-bar voltage and output end current, realize simple, but because the influence of vector alignment voltage in can't compensating, thus can only be by the symmetry of middle vector self, at a complete output voltage in the cycle, finish neutral point voltage balance, cause mid-point voltage to have very big low-frequency ripple; Two, detect the dc capacitor voltage size, according to the offset direction of mid-point voltage, rationally arrange the action time of PWM (abbreviation of Pulse WidthModulation, the i.e. pulse width modulation) pulse of positive and negative small vector then, carry out the mid-point voltage compensation, but this method algorithm is very complicated; Three, detect dc capacitor voltage size and three-phase alternating current output current, this method obtains directivity function by real-time detection three-phase alternating current output current direction, utilize this function to select in the PWM cycle generating positive and negative voltage vector to control the mid point sense of current action time, realize the balance of voltage, this in theory method is fine good, and it can calculate the concrete time of compensation, but the data that this method will be sampled are many, amount of calculation is bigger, to having relatively high expectations of software and hardware.
Summary of the invention:
The objective of the invention is to overcome the deficiencies in the prior art, a kind of method of utilizing time factor balancing three-level direct current mid-point voltage is provided, realize three level neutral point voltage balances simply and easily.
In order to achieve the above object, the technical solution used in the present invention is:
A kind of method of utilizing time factor balancing three-level direct current mid-point voltage, step is as follows:
Step 1, beginning alignment voltage and mid point electric current are sampled, and alignment voltage and mid point electric current are judged;
Step 2, mid-point voltage are non-vanishing, execution in step 3, and mid-point voltage is zero, skips to step 5;
Step 3, mid-point voltage greater than zero and the mid point electric current greater than zero the time negative small vector according to time factor fine setting offset mid-point voltage greater than zero part,
Mid-point voltage less than zero and the mid point electric current less than zero the time positive small vector according to time factor fine setting offset mid-point voltage greater than zero part,
Mid-point voltage less than zero and the mid point electric current greater than zero the time positive small vector according to time factor fine setting offset mid-point voltage greater than zero part,
Mid-point voltage greater than zero and the mid point electric current less than zero the time negative small vector according to time factor k fine setting offset mid-point voltage greater than zero part;
Mid-point voltage after step 4, the positive and negative small vector of process are offset reaches balance;
Step 5, EP (end of program).
The present invention adopts time factor to distribute the action time of the positive and negative state of a pair of small vector in the sampling period, the control mid-point voltage.Be Tx the action time of supposing controlled small vector, the k express time factor, be kTx the negative small vector action time when then beginning, be (1-k) Tx the action time of positive small vector, the mid-point voltage value is the poor of DC side dividing potential drop capacitance voltage Vdc1 and Vdc2, the mid point electric current flows out direction for just, and concrete control law is:
Vdc1-Vdc2>h and I
0>0 k value is got (1-k), and the time of positive small vector effect is (1-k) Tx;
Vdc1-Vdc2>h and I
0<0 k value is constant, and the time of negative small vector effect is kTx;
Vdc1-Vdc2<-h and I
0>0 k value is constant, and the time of negative small vector effect is kTx;
Vdc1-Vdc2<-h and I
0<0 k value is got (1-k), and the time of positive small vector effect is (1-k) Tx.
H is that the stagnant endless belt of voltage is wide, I
0Be the mid point electric current, k is an experimental data, traffic direction according to detected magnitude of voltage, current value and voltage and current in active power filter is adjusted size, decide positive and negative small vector pwm pulse to act on the time of system, the size of adjustment is according to the size of the wide h of stagnant endless belt in 4 relational expressions.
Find out from above four formulas, need not just can keep the balance of mid-point voltage, simultaneously because the wide existence of endless belt that stagnates makes that k value amplitude of variation is little through complicated logic determines, control by the real-time alignment magnitude of voltage of negative feed back control system, reach the balance of mid-point voltage.
Compared with prior art, the invention has the beneficial effects as follows: the first, utilize time factor k that the positive and negative small vector of three level mid-point voltages is finely tuned, reach neutral point voltage balance, easy and simple to handle; The second, the voltage fluctuation on the dc bus capacitor is little, has prolonged the life-span of electric capacity; Three, sampled data is few, to software and hardware require low.
Description of drawings:
Fig. 1 is a theory diagram of the present invention;
Fig. 2 is the three dimensional vector diagram of three level of the present invention.
Embodiment:
Central idea of the present invention is to overcome the deficiencies in the prior art, and a kind of method of utilizing time factor balancing three-level direct current mid-point voltage is provided, can simple and effective realization three level neutral point voltage balances.Be elaborated with reference to accompanying drawing below in conjunction with embodiment, so that technical characterictic of the present invention and advantage are carried out more deep annotation.
Theory diagram of the present invention as shown in Figure 1, a kind of method of utilizing time factor balancing three-level direct current mid-point voltage, step is as follows:
Step 1, beginning alignment voltage and mid point electric current are sampled, and alignment voltage and mid point electric current are judged;
Step 2, mid-point voltage are non-vanishing, execution in step 3, and mid-point voltage is zero, skips to step 5;
Step 3, mid-point voltage greater than zero and the mid point electric current greater than zero the time negative small vector according to time factor fine setting offset mid-point voltage greater than zero part,
Mid-point voltage less than zero and the mid point electric current less than zero the time positive small vector according to time factor fine setting offset mid-point voltage greater than zero part,
Mid-point voltage less than zero and the mid point electric current greater than zero the time positive small vector according to time factor fine setting offset mid-point voltage greater than zero part,
Mid-point voltage greater than zero and the mid point electric current less than zero the time negative small vector according to time factor k fine setting offset mid-point voltage greater than zero part;
Mid-point voltage after step 4, the positive and negative small vector of process are offset reaches balance;
Step 5, EP (end of program).
The present invention adopts time factor to distribute the action time of the positive and negative state of a pair of small vector in the sampling period, the control mid-point voltage.Be Tx the action time of supposing controlled small vector, the k express time factor, be kTx the negative small vector action time when then beginning, be (1-k) Tx the action time of positive small vector, the mid-point voltage value is the poor of DC side dividing potential drop capacitance voltage Vdc1 and Vdc2, the mid point electric current flows out direction for just, and concrete control law is:
Vdc1-Vdc2>h and I
0>0 k value is got (1-k), and the time of positive small vector effect is (1-k) Tx;
Vdc1-Vdc2>h and I
0<0 k value is constant, and the time of negative small vector effect is kTx;
Vdc1-Vdc2<-h and I
0>0 k value is constant, and the time of negative small vector effect is kTx;
Vdc1-Vdc2<-h and I
0<0 k value is got (1-k), and the time of positive small vector effect is (1-k) Tx.
H is that the stagnant endless belt of voltage is wide, I
0Be the mid point electric current, the span of time factor k is an experimental data, according to the size of adjusting k at the traffic direction of the detected magnitude of voltage of active power filter, current value and voltage and current, decide the time of the system that acts on of positive and negative small vector pwm pulse, the size of adjustment is according to the size of the wide h of stagnant endless belt in 4 relational expressions.
Find out from above four formulas, need not just can keep the balance of mid-point voltage, simultaneously because the wide existence of endless belt that stagnates makes that k value amplitude of variation is little through complicated logic determines, control by the real-time alignment magnitude of voltage of negative feed back control system, reach the balance of mid-point voltage.
The three dimensional vector diagram of three level as shown in Figure 2, A, B, C are three level voltages, synthetic vector voltage can be divided three classes among the figure:
6 of long vectors: PNN, PNP, NNP, NPP, NPN, PPN, be positioned at orthohexagonal summit, three switches all only have P, N two states.
In 6 of vectors: PON, OPN, NPO, NOP, ONP, OPN are positioned at the mid point on every limit of regular hexagon.
6 pairs of short vectors: POO, ONN, PPO, OON, OPO, NON, OPP, NOO, OOP, NNO, POP, ONO are the small voltage vector of 12 2DOFs, are positioned at regular hexagon center and summit line mid point.
Short vector voltage is three level DC mid-point voltage of the present invention, when mid-point voltage value and theoretical value have deviation, controls the time fine tuning mid-point voltage value of positive and negative small vector effect by time factor k, reaches the balance of three level mid-point voltages.
Claims (6)
1. method of utilizing time factor balancing three-level direct current mid-point voltage, step is as follows:
Step 1, beginning alignment voltage and mid point electric current are sampled, and alignment voltage and mid point electric current are judged;
Step 2, mid-point voltage are non-vanishing, execution in step 3, and mid-point voltage is zero, skips to step 5;
Step 3, mid-point voltage greater than zero and the mid point electric current greater than zero the time negative small vector according to time factor fine setting offset mid-point voltage greater than zero part,
Mid-point voltage less than zero and the mid point electric current less than zero the time positive small vector according to time factor fine setting offset mid-point voltage greater than zero part,
Mid-point voltage less than zero and the mid point electric current greater than zero the time positive small vector according to time factor fine setting offset mid-point voltage greater than zero part,
Mid-point voltage greater than zero and the mid point electric current less than zero the time negative small vector according to time factor k fine setting offset mid-point voltage greater than zero part;
Mid-point voltage after step 4, the positive and negative small vector of process are offset reaches balance;
Step 5, EP (end of program).
2. the method for utilizing time factor balancing three-level direct current mid-point voltage according to claim 1 is characterized in that: described three level mid-point voltage values are the poor of DC side dividing potential drop capacitance voltage Vdc1 and Vdc2.
3. the method for utilizing time factor balancing three-level direct current mid-point voltage according to claim 2 is characterized in that: the span of described time factor is according to the traffic direction adjustment of the detected magnitude of voltage of active filter, current value and voltage and current.
4. the method for utilizing time factor balancing three-level direct current mid-point voltage according to claim 3, it is characterized in that: be Tx the action time of described controlled small vector, k is a time factor, and then negative small vector action time is kTx, and be (1-k) Tx the action time of positive small vector.
5. the method for utilizing time factor balancing three-level direct current mid-point voltage according to claim 4 is characterized in that: the action time of described positive and negative small vector, concrete control law was by the direction and the time factor k control of mid-point voltage
Vdc1-Vdc2>h and I
0>0 k value is got (1-k), and the time of positive small vector effect is (1-k) Tx;
Vdc1-Vdc2>h and I
0<0 k value is constant, and the time of negative small vector effect is kTx;
Vdc1-Vdc2<-h and I
0>0 k value is constant, and the time of negative small vector effect is kTx;
Vdc1-Vdc2<-h and I
0<0 k value is got (1-k), and the time of positive small vector effect is (1-k) Tx.
6. the method for utilizing time factor balancing three-level direct current mid-point voltage according to claim 5 is characterized in that: described h is that the stagnant endless belt of voltage is wide, I
0Be the mid point electric current, the value of time factor k is adjusted size according to the traffic direction of detected magnitude of voltage, current value and voltage and current.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN2010101555396A CN101834443B (en) | 2010-04-22 | 2010-04-22 | Method for balancing three-level direct current midpoint voltage by using time factor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN2010101555396A CN101834443B (en) | 2010-04-22 | 2010-04-22 | Method for balancing three-level direct current midpoint voltage by using time factor |
Publications (2)
Publication Number | Publication Date |
---|---|
CN101834443A true CN101834443A (en) | 2010-09-15 |
CN101834443B CN101834443B (en) | 2013-04-24 |
Family
ID=42718415
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN2010101555396A Expired - Fee Related CN101834443B (en) | 2010-04-22 | 2010-04-22 | Method for balancing three-level direct current midpoint voltage by using time factor |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN101834443B (en) |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN103095166A (en) * | 2013-01-30 | 2013-05-08 | 华为技术有限公司 | Modulating method and modulating equipment of space vector pulse width |
CN103178737A (en) * | 2013-03-25 | 2013-06-26 | 江苏宝丰新能源科技有限公司 | Hysteresis control method for keeping midpoint voltage balance of three-level photovoltaic inverter |
CN104158422A (en) * | 2014-07-30 | 2014-11-19 | 华南理工大学 | Mid-point voltage control method for midpoint clamping type three-level inverter |
CN104167947A (en) * | 2014-07-18 | 2014-11-26 | 山东大学 | Z-source three-level T-type inverter and neutral-point balance control method thereof |
CN105610339A (en) * | 2015-12-22 | 2016-05-25 | 深圳市泰昂能源科技股份有限公司 | Three-level modulation method for novel virtual space vectors |
CN106533230A (en) * | 2016-12-15 | 2017-03-22 | 东南大学 | Three-level virtual space vector voltage equalizing modulation method based on simplified balance factor |
CN106787917A (en) * | 2017-01-16 | 2017-05-31 | 华南理工大学 | A kind of NP complementary type SVPWM control methods of three-phase tri-level inverter |
CN108270367A (en) * | 2017-10-17 | 2018-07-10 | 天津铁科运通轨道技术有限公司 | A kind of three-level current transformer neutral balance control method |
CN109617440A (en) * | 2018-12-12 | 2019-04-12 | 上海电机学院 | Three-level inverter DC side neutral point voltage balance method based on SVPWM |
CN111224573A (en) * | 2020-01-20 | 2020-06-02 | 北京瑞盈同创智能技术研究院有限公司 | Current polarity-based midpoint potential balance control method and device |
CN113395008A (en) * | 2021-07-27 | 2021-09-14 | 盾石磁能科技有限责任公司 | Midpoint balance control method of flywheel energy storage motor driving circuit in charging process |
CN114614693A (en) * | 2022-05-11 | 2022-06-10 | 深圳库马克科技有限公司 | Balancing method and balancing device for midpoint voltage |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1481067A (en) * | 2003-07-25 | 2004-03-10 | 清华大学 | Method of mid point balance of voltage utilized in frequency converter in three levels based on charge balance |
CN101667806A (en) * | 2009-03-04 | 2010-03-10 | 深圳职业技术学院 | Space vector pulse width modulation controller of tri-level circuit and control method thereof |
-
2010
- 2010-04-22 CN CN2010101555396A patent/CN101834443B/en not_active Expired - Fee Related
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1481067A (en) * | 2003-07-25 | 2004-03-10 | 清华大学 | Method of mid point balance of voltage utilized in frequency converter in three levels based on charge balance |
CN101667806A (en) * | 2009-03-04 | 2010-03-10 | 深圳职业技术学院 | Space vector pulse width modulation controller of tri-level circuit and control method thereof |
Non-Patent Citations (3)
Title |
---|
《机械制造与自动化》 20050130 刘丽俊等 一种新型的三电平逆变器中点电压平衡控制策略 第34卷, 第01期 * |
《船电技术》 20090515 阮会 三电平中点电压平衡PWM控制策略研究 第29卷, 第05期 * |
《黑龙江科技学院学报》 20070130 卫建荣等 三电平逆变器的点电压平衡控制 第17卷, 第01期 * |
Cited By (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN103095166B (en) * | 2013-01-30 | 2015-03-18 | 华为技术有限公司 | Modulating method and modulating equipment of space vector pulse width |
CN103095166A (en) * | 2013-01-30 | 2013-05-08 | 华为技术有限公司 | Modulating method and modulating equipment of space vector pulse width |
CN103178737A (en) * | 2013-03-25 | 2013-06-26 | 江苏宝丰新能源科技有限公司 | Hysteresis control method for keeping midpoint voltage balance of three-level photovoltaic inverter |
CN104167947A (en) * | 2014-07-18 | 2014-11-26 | 山东大学 | Z-source three-level T-type inverter and neutral-point balance control method thereof |
CN104167947B (en) * | 2014-07-18 | 2017-04-12 | 山东大学 | Z-source three-level T-type inverter and neutral-point balance control method thereof |
CN104158422A (en) * | 2014-07-30 | 2014-11-19 | 华南理工大学 | Mid-point voltage control method for midpoint clamping type three-level inverter |
CN105610339B (en) * | 2015-12-22 | 2018-03-02 | 国家电网公司 | A kind of three-level modulation method of Virtual Space vector |
CN105610339A (en) * | 2015-12-22 | 2016-05-25 | 深圳市泰昂能源科技股份有限公司 | Three-level modulation method for novel virtual space vectors |
CN106533230A (en) * | 2016-12-15 | 2017-03-22 | 东南大学 | Three-level virtual space vector voltage equalizing modulation method based on simplified balance factor |
CN106787917A (en) * | 2017-01-16 | 2017-05-31 | 华南理工大学 | A kind of NP complementary type SVPWM control methods of three-phase tri-level inverter |
CN106787917B (en) * | 2017-01-16 | 2019-05-14 | 华南理工大学 | A kind of NP complementary type SVPWM control method of three-phase tri-level inverter |
CN108270367A (en) * | 2017-10-17 | 2018-07-10 | 天津铁科运通轨道技术有限公司 | A kind of three-level current transformer neutral balance control method |
CN109617440A (en) * | 2018-12-12 | 2019-04-12 | 上海电机学院 | Three-level inverter DC side neutral point voltage balance method based on SVPWM |
CN109617440B (en) * | 2018-12-12 | 2021-03-12 | 上海电机学院 | SVPWM-based three-level inverter direct-current side midpoint voltage balancing method |
CN111224573A (en) * | 2020-01-20 | 2020-06-02 | 北京瑞盈同创智能技术研究院有限公司 | Current polarity-based midpoint potential balance control method and device |
CN113395008A (en) * | 2021-07-27 | 2021-09-14 | 盾石磁能科技有限责任公司 | Midpoint balance control method of flywheel energy storage motor driving circuit in charging process |
CN113395008B (en) * | 2021-07-27 | 2022-08-23 | 盾石磁能科技有限责任公司 | Midpoint balance control method of flywheel energy storage motor driving circuit in charging process |
CN114614693A (en) * | 2022-05-11 | 2022-06-10 | 深圳库马克科技有限公司 | Balancing method and balancing device for midpoint voltage |
Also Published As
Publication number | Publication date |
---|---|
CN101834443B (en) | 2013-04-24 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN101834443B (en) | Method for balancing three-level direct current midpoint voltage by using time factor | |
US8400792B2 (en) | Power conversion apparatus | |
US10910859B2 (en) | Smart cells and control methods and systems | |
US8547073B2 (en) | Output side capacitor voltage balancing DC power supply system | |
KR101682265B1 (en) | Electricity-storage device that can output alternating current | |
US9048754B2 (en) | System and method for offsetting the input voltage unbalance in multilevel inverters or the like | |
US8649196B2 (en) | Power converting apparatus with an output voltage that is the sum of voltages generated by individual inverters | |
CA2722263C (en) | Uninterruptible power supply apparatus | |
US10079558B2 (en) | Switching scheme for static synchronous compensators using cascaded H-bridge converters | |
EP3113350B1 (en) | Modular multi-level converter and method of controlling voltage balancing of modular multi-level converter | |
WO2016188433A1 (en) | Power supply system and power supply method | |
US8923027B2 (en) | Five-level DC-AC converter | |
CN103401452A (en) | VSVPWM (Virtual Space Vector Pulse Width Modulation)-based three-level inverter neutral point potential compensation balance control strategy | |
CN106451544B (en) | A kind of united three level grid-connected system control method of light storage | |
WO2012154810A2 (en) | Power conversion apparatus and methods employing variable-level inverters | |
US20140055104A1 (en) | Adaptive DC-link voltage controlled LC coupling hybrid active power filters for reactive power compensation | |
US20170256950A1 (en) | Multi-Level Converter and Method of Operating Same | |
US20140119074A1 (en) | Operation of multichannel active rectifier | |
Rajakumar et al. | Enhancement of power quality using double‐band hysteresis controller for the grid integrated renewable energy system | |
JP2013230027A (en) | Ac power supply system | |
CN107342623B (en) | Variable carrier variable modulation wave phase-shifting SPWM (sinusoidal pulse Width modulation) method based on cascade energy storage system | |
EP3238320A1 (en) | Battery charging method and apparatus with power point check and switchable control | |
US20230075792A1 (en) | Multi-level inverter | |
Bezhenar et al. | Multilevel inverter as var-compensator | |
Lyu et al. | A new DPWM method to suppress the low frequency oscillation of the neutral-point voltage for NPC three-level inverters |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
C06 | Publication | ||
PB01 | Publication | ||
C10 | Entry into substantive examination | ||
SE01 | Entry into force of request for substantive examination | ||
C14 | Grant of patent or utility model | ||
GR01 | Patent grant | ||
CF01 | Termination of patent right due to non-payment of annual fee | ||
CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130424 Termination date: 20190422 |