在PHP中将Excel转换为CSV时，Excel函数显示为原样

We are converting excel to CSV with every sheet. For example if a excel file has 5 sheets then we are converting 5 CSV file for every sheet. Its working fine except one thing. As we know excel sheet has some formulas for calculation like sum, Average etc..., So when we are converting them to CSV file, Then function is showing as it is, Their calculated value is not showing, which we can read as a excel sheet.

This is the function which we are using

function write_csv($filename,$definename){

     $dir = "";  
       $file_arr = array();
     array_push($file_arr, $filename);  
    // Make CSV File 
    $list = array();
    foreach($file_arr as $val)
    {
        $arr_data = array();
     // echo $val;

        $objPHPExcel = PHPExcel_IOFactory::load($dir . $val);

      //  print_r($objPHPExcel->getSheetNames());exit;
        $loadedSheetNames = $objPHPExcel->getSheetNames();
        foreach($loadedSheetNames as $sheetIndex => $loadedSheetName) {
       // echo $sheetIndex;
        $objPHPExcel->setActiveSheetIndex($sheetIndex);

                $fp = fopen($definename.'_'.$sheetIndex.'.csv', 'a');
        $cell_collection = $objPHPExcel->getActiveSheet()->getCellCollection();
      //  print_r($cell_collection);
        foreach($cell_collection as $cell)
        {
            $column = $objPHPExcel->getActiveSheet()->getCell($cell)->getColumn();
            $row = $objPHPExcel->getActiveSheet()->getCell($cell)->getRow();
            $data_value = $objPHPExcel->getActiveSheet()->getCell($cell)->getValue();
            //header will / should be in row 1 only. of course this can be modified to suit your need.
            // Skip Rows From Top if you have header in Excel then Change 0 to 1
            if($row == 0)
            {
                $header[$row][$column] = $data_value;
            }
            else
            {
                $arr_data[$row]['row'] = $row;
                $arr_data[$row][$column] = $data_value;
            }
        }
        $data = $arr_data;
        foreach($data as $val1)
        {
            $num_col = sizeof($val1) - 1;  // get number of columns in Excel 
            break;
        }
        $lwrcol=array();    
        foreach($data as $val2)
        {
            $alphaArr = range('A','Z');
            $colArr = range('A',$alphaArr[$num_col - 1]);

            foreach($colArr as $col)
            {
                $lwrcol[$col] = isset($val2[$col]) ? utf8_decode($val2[$col]) : "";
                fwrite($fp,$lwrcol[$col].",");
            }
            fwrite($fp,"
");   
        }
       // chmod(getcwd()."/file.csv", 0777);
                fclose($fp);
            }
    }
}

Please tell me what we are doing wrong.

Complete Code:

http://pastebin.com/DaRBSpqP