试试这个：

<?php

$string = 'IBAÑEZ RIBERA, ALBA, á â à å ä ð é ê è ë í î ì ï ó ô ò ø õ ö ú û ù ü æ ç ß abc ABC 123';

$value = iconv('UTF-8','ASCII//TRANSLIT',$string);

echo $value;
?>

将生成输出：

IBANEZ RIBERA, ALBA, a a a a a d e e e e i i i i o o o o o o u u u u ae c ss abc ABC 123

更新：
由于我在回答或评论中的建议都不起作用，请使用以下命令：

<?php

$string = 'IBAÑEZ RIBERA, ALBA'; 

function changeChar($string){

$chars = array(
    'À'=>'A','Á'=>'A','Â'=>'A','Ã'=>'A','Ä'=>'A','Å'=>'A',
    'Æ'=>'A','Ç'=>'C','È'=>'E','É'=>'E','Ê'=>'E','Ë'=>'E',
    'Ì'=>'I','Í'=>'I','Î'=>'I','Ï'=>'I','Ð'=>'Dj','Ñ'=>'N',
    'Ò'=>'O','Ó'=>'O','Ô'=>'O','Õ'=>'O','Ö'=>'O','Ø'=>'O',
    'Ù'=>'U','Ú'=>'U','Û'=>'U','Ü'=>'U','Ý'=>'Y','Þ'=>'B',
    'ß'=>'Ss','à'=>'a','á'=>'a','â'=>'a','ã'=>'a','ä'=>'a',
    'å'=>'a','æ'=>'a','ç'=>'c','è'=>'e','é'=>'e','ê'=>'e',
    'ë'=>'e','ì'=>'i','í'=>'i','î'=>'i','ï'=>'i','ð'=>'o',
    'ñ'=>'n','ò'=>'o','ó'=>'o','ô'=>'o','õ'=>'o','ö'=>'o',
    'ø'=>'o','ù'=>'u','ú'=>'u','û'=>'u','ü'=>'u','ý'=>'y',
    'þ'=>'b','ÿ'=>'y','Ă'=>'A','ă'=>'a','Ń'=>'N','ń'=>'n',
    'Š'=>'S','š'=>'s','Ž'=>'Z','ž'=>'z','ƒ'=>'f','Ș'=>'S',
    'ș'=>'s','Ț'=>'T','ț'=>'t',
);
    return strtr($string, $chars);
    //or return str_replace(array_keys($chars), array_values($chars), $string);
}

echo changeChar($string);

它不漂亮，但在大多数情况下都能用。