对数据库查询操作时如果使用了where语句后报错Array to string conversion [ 2.0 版本 ]

这个是EquipmentArchives类的代码：

<?php

namespace app\models;


use yii\db\ActiveRecord;
use yii\helpers\HtmlPurifier;

/**
 * This is the model class for table "ledger".
 *
 * @property string $id
 * @property integer $eid
 * @property string $city
 * @property string $entname
 * @property string $ent_type
 * @property string $name
 * @property string $type
 * @property string $io
 * @property string $model
 * @property string $_level
 * @property string $_range
 * @property string $vendor
 * @property string $serial
 * @property string $managenum
 * @property string $place
 * @property string $note
 * @property string $rec_time
 * @property string $status_time
 * @property string $jdtime
 * @property integer $jdcycle
 */
class EquipmentArchives extends ActiveRecord
{
    /**
     * @inheritdoc
     */
    public static function tableName()
    {
        return 'ledger';
    }

    /**
     * @inheritdoc
     */
    public function rules()
    {
        return [
            [['eid', 'city', 'entname', 'ent_type', 'name', 'type', 'io', 'model', '_level', '_range', 'vendor', 'serial', 'managenum', 'place', 'rec_time', 'status_time', 'jdtime', 'jdcycle'], 'required'],
            [['eid', 'jdcycle'], 'integer'],
            [['rec_time', 'status_time', 'jdtime'], 'safe'],
            [['city', 'ent_type', 'name', 'type', 'io', 'model', '_level', '_range', 'vendor', 'serial', 'managenum', 'place'], 'string', 'max' => 50],
            [['entname'], 'string', 'max' => 200],
            [['note'], 'string', 'max' => 255],
        ];
    }

    /**
     * @inheritdoc
     */
    public function attributeLabels()
    {
        return [
            'id' => '编号',
            'eid' => 'Eid',
            'city' => '所在城市',
            'entname' => '企业名称',
            'ent_type' => '组织规模',
            'name' => '计量器具名称',
            'type' => '器具类别',
            'io' => '输入输出用能',
            'model' => '型号规格',
            '_level' => '准确度等级',
            '_range' => '测量范围',
            'vendor' => '生产厂家',
            'serial' => '出厂编号',
            'managenum' => '用能单位管理编号',
            'place' => '安装使用地点',
            'note' => '备注',
            'rec_time' => '录入时间',
            'status_time' => '状态发生时间',
            'jdtime' => '检定时间',
            'jdcycle' => '检定周期',
        ];
    }

    public static function findById($id)
    {
        return static::findOne(['id'=>$id]);
    }

    public function add()
    {
        $record = new EquipmentArchives();

        $record->eid = HtmlPurifier::process($this->eid);
        $record->city = HtmlPurifier::process($this->city);
        $record->entname = HtmlPurifier::process($this->entname);
        $record->ent_type = HtmlPurifier::process($this->ent_type);
        $record->name = HtmlPurifier::process($this->name);
        $record->type = HtmlPurifier::process($this->type);
        $record->io = HtmlPurifier::process($this->io);
        $record->model = HtmlPurifier::process($this->model);
        $record->_level = HtmlPurifier::process($this->_level);
        $record->_range = HtmlPurifier::process($this->_range);
        $record->vendor = HtmlPurifier::process($this->vendor);
        $record->serial = HtmlPurifier::process($this->serial);
        $record->managenum = HtmlPurifier::process($this->managenum);
        $record->place = HtmlPurifier::process($this->place);
        $record->rec_time = HtmlPurifier::process($this->rec_time);
        $record->status_time = HtmlPurifier::process($this->status_time);
        $record->jdtime = HtmlPurifier::process($this->jdtime);
        $record->jdcycle = HtmlPurifier::process($this->jdcycle);
        $record->note = HtmlPurifier::process($this->note);

        return $record->save();
    }
}

写这么清楚还是没有人回答？