有源功率因数校正可减少用电设备对电网的谐波污染,提高电器设备输入端的功率因数。详细分析了有源功率因数校正APFC(active power factor corrector)原理,采用平均电流控制模式控制原理,设计了基于UC3854BN芯片的一种有源功率因数校正电路方案,着重分析了电路主要参数的选择和设计。实践证明,采用APFC后,大大减小了输入电流的谐波分量,实现了功率因数校正。
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.001864s ]
SELECT `a`.`aid`,`a`.`title`,`a`.`create_time`,`m`.`username` FROM `jrk_downrecords` `a` INNER JOIN `jrk_member` `m` ON `a`.`uid`=`m`.`id` WHERE `a`.`status` = 1 GROUP BY `a`.`aid` ORDER BY `a`.`create_time` DESC LIMIT 10 [ RunTime:0.092708s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.001266s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.001893s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.001222s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.003635s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.001051s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.003236s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.015184s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001355s ]
UPDATE `jrk_articles` SET `hits` = 1 WHERE `id` = 527156 [ RunTime:0.001386s ]