Title:
NEUTRAL POINT BALANCE CONTROL METHOD AND SYSTEM FOR THREE-LEVEL CONVERTER OF FULL POWER FACTOR RANGE
Document Type and Number:
WIPO Patent Application WO/2020/177238
Kind Code:
A1
Abstract:
Disclosed are a neutral point balance control method and system for a three-level converter of a full power factor range. The method comprises: synthesizing a reference voltage vector by using a large vector modulation method, a medium vector modulation method, and a zero vector modulation method, and respectively determining duty ratios of a large vector, a medium vector, and a zero vector; obtaining a voltage difference between two capacitor groups on a direct-current side by means of signal acquisition, and determining the voltage difference as a neutral point potential of the three-level converter; selecting a small vector and calculating a duty ratio of the small vector according to a magnitude relationship between the neutral point potential of the three-level converter and a set threshold; and updating the duty ratios of basic vectors to obtain a switching sequence for controlling a three-phase leg power switch tube. The amplitude of a common-mode voltage of an NPC three-level converter obtained by the method of the present invention is equal to one sixth of the voltage on the direct-current side. Compared with a conventional space vector modulation method, the amplitude of the common-mode voltage is reduced by one-half, the electromagnetic interference of the system is reduced, and the adverse effect of the common-mode voltage on a motor winding is effectively reduced.
Inventors:
ZHANG CHENGHUI (CN)
QIN CHANGWEI (CN)
LI XIAOYAN (CN)
XING XIANGYANG (CN)
HU SHUNQUAN (CN)
JIANG YING (CN)
CHEN ALIAN (CN)
QIN CHANGWEI (CN)
LI XIAOYAN (CN)
XING XIANGYANG (CN)
HU SHUNQUAN (CN)
JIANG YING (CN)
CHEN ALIAN (CN)
Application Number:
PCT/CN2019/091773
Publication Date:
September 10, 2020
Filing Date:
June 18, 2019
Export Citation:
Assignee:
UNIV SHANDONG (CN)
International Classes:
H02M1/12; H02M7/487; H02M1/44
Foreign References:
| CN109787498A | 2019-05-21 | |||
| CN106253647A | 2016-12-21 | |||
| CN104779826A | 2015-07-15 | |||
| US7558089B2 | 2009-07-07 | |||
| CN204597799U | 2015-08-26 | |||
| CN107196536A | 2017-09-22 |
Attorney, Agent or Firm:
JINAN SHENGDA INTELLECTUAL PROPERTY AGENCY CO., LTD. (CN)
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