高速电主轴矢量控制方法的研究
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目 录
中文摘要
ABSTRACT
第一章 绪论 ························································································ 1
§1.1 研究背景及意义 ········································································1
§1.2 国内外研究现状及发展趋势 ························································ 2
§1.2.1 电主轴技术研究现状 ·····························································2
§1.2.2 国内外高速电主轴技术的差距 ················································ 3
§1.2.3 电主轴技术的发展趋势 ··························································4
§1.3 关键技术 ·················································································5
§1.3.1 矢量控制策略 ······································································5
§1.3.2 无速度传感器的矢量控制调节方式 ·········································· 6
§1.3.3 磁通观测技术 ······································································7
§1.4 本文主要研究内容 ·····································································7
第二章 电主轴矢量控制系统理论 ·····························································9
§2.1 矢量控制的基本原理 ··································································9
§2.1.1 高速交流异步电主轴的三相静止坐标系数学模型 ························ 9
§2.1.2 矢量控制的坐标变换 ··························································· 12
§2.1.3 三相异步电主轴电机在两相坐标系上的数学模型 ·······················15
§2.1.4 转子磁场定向矢量控制基本原理 ············································ 17
§2.2 异步电主轴电机转子磁链观测 ····················································19
§2.2.1 转子磁链的直接检测 ··························································· 19
§2.2.2 转子磁链的间接检测 ··························································· 19
§2.2.3 改进电压型的混合式磁通观测器 ·············································23
第三章 电主轴的无速度传感器矢量控制系统 ············································ 24
§3.1 异步电动机转速辨识方法 ···························································24
§3.1.1 扩展卡尔曼滤波器法 ··························································· 24
§3.1.2 基于人工神经元网络法 ························································ 24
§3.1.3 模型参考自适应法 ······························································ 25
§3.2 瞬时无功功率 MRAS 转速辨识方法 ··············································26
§3.2 PWM 控制技术 ········································································ 28
§3.2.1 正弦脉宽调制技术 ······························································ 28
§3.2.2 电流滞环跟踪型 PWM 技术 ·················································· 29
§3.2.3 空间矢量脉宽调制原理及实现 ··············································· 29
第四章 矢量控制系统的仿真 ································································· 36
§4.1 异步电主轴的仿真模型 ····························································· 36
§4.1.1 三相异步电主轴在两相坐标系上的状态方程 ·····························36
§4.1.2 基于 S-Function 的异步电主轴仿真模型 ··································· 37
§4.2 异步电主轴的仿真 ··································································· 37
§4.3 子模块的建立 ········································································· 40
§4.4 矢量坐标变换的仿真 ································································ 42
§4.5 电压空间矢量 SVPWM 的仿真 ··················································· 43
§4.6 不同情况下的仿真比较 ····························································· 46
第五章 基于 DSP 的无速度传感器矢量控制系统硬件设计 ····························51
§5.1 DSP 控制系统的设计过程与开发工具 ··········································· 51
§5.2 TMS320LF2407A DSP 与目标板 ·················································· 53
§5.3 电源板 ·················································································· 54
§5.3.1 整流电路 ·········································································· 54
§5.3.2 滤波电路 ·········································································· 54
§5.3.3 限流电路 ·········································································· 54
§5.4 功率驱动板 ············································································ 54
§5.4.1 逆变电路设计及 IGBT 驱动 ·················································· 54
§5.4.2 电流检测电路 ···································································· 55
§5.4.3 电压检测电路 ···································································· 56
第六章 无速度传感器矢量控制系统的软件实现 ········································· 57
§6.1 高速电主轴矢量控制系统的 DSP 结构原理 ····································57
§6.2 系统软件实现 ········································································· 58
§6.3.1 DSP 的主程序 ·····································································58
§6.3.2 串口通信中断服务子程序 ····················································· 59
§6.3 无速度传感器矢量控制系统的 DSP 实现 ·······································59
§6.3.1 电压、电流的采样及规格化 ·················································· 60
§6.3.2 PI 调节器的 DSP 实现方法 ···················································· 60
§6.3.3 瞬时无功功率 MRAS 转速辨识算法的 DSP 实现 ························62
§6.3.4 电压空间矢量的 DSP 实现方法 ·············································· 63
§6.4 软件调试 ··············································································· 65
§6.5 实验结果分析 ········································································· 66
第七章 全文总结及展望 ······································································· 69
附 录 ································································································ 71
参考文献 ··························································································· 77
在读期间公开发表的论文和承担科研项目及取得成果 ································· 82
致 谢 ································································································ 83
第一章 绪论
1
第一章 绪论
§1.1 研究背景及意义
近20 年来,在制造业中出现了以高切削速度、高进给速度和高加工精度为主
要特征的加工技术,它使制造技术产生第二次革命性飞跃,在工业各部门不同领
域获得广泛的应用[1]。与传统加工方式相比,它具有效率高、表面质量好、成本低,
易于实现难加工材料的精密加工等优点。
为了满足汽车、航空航天等领域对金属材料零件的高速精密加工,要求现代
数控机床具备转速高、精度高、效率高以及可靠率高的特点,同时尽量用干切削
的方式来加工零件。为此超高速数控机床成为超高速加工的物质基础,而高速电
主轴又是超高速数控机床的核心部件[2],其内部结构如图 1-1 所示。
1.壳体 2.主轴 3.过盈套 4.转子 5.气隙 6.定子 7.冷却水套
8.轴承 9.润滑系统入口 10.冷却 水出口 11.接电源 12.冷却水入口
图1-1 高速电主轴系统主轴单元结构简图
高速数控机床随着电气传动技术(变频调速技术、电动机矢量控制技术等)
的迅速发展而日趋完善,基本上替代了带轮传动和齿轮传动,其机械结构得到极
大的简化。机床主轴由内装式电动机直接驱动,取消了一切中间环节,把机床传
动链的长度缩短为零,实现了主轴系统的零传动,俗称电主轴 (Electro-Spindle),
亦称 Motor-Spindle 或Motorized-Spindle。交流变频控制系统,是主轴获得所需的
工作速度和转矩,实现电机主轴一体化功能的保障。采用了变频调速技术的高速
电主轴,有较大的驱动功率和转矩,附有监控主轴温升、振动等参数的检测控制
系统,采用负载与电动机直接耦合,即同轴运行的传动方式,它涉及机械、电机、
驱动与控制、支承和润滑、以及振动等领域,融合了高速轴承技术、高速电机技
术、高速刀具技术、冷却润滑技术、现代变流技术以及先进的计算机控制技术等,
高速电主轴矢量控制方法的研究
2
是一套相对独立完整的职能部件。由于当前主要采用的是交流高频电动机,所以
电主轴也称为高频主轴(High Frequency Spindle)。另外,由于没有中间传动环节,
有时又称为直接驱动主轴[3](Direct Drive Spindle)。
高速电主轴的结构主要包括电主轴主要部件——轴壳、测试动平衡的主要回
转体——转轴、核心支撑部件——轴承、由具有高导磁率的优质矽钢片迭压而成
的定子、由转子铁芯、鼠笼和转轴组成的转子。
高速电主轴的工作原理和异步电动机的工作原理完全一致,当相位互差 120°
的三相绕组通以三相交流电后,便形成正弦交变磁场,其转速就是同步转速 n,它
是由输入电流的频率 f和定子的极对数 Np决定(n=60f/Np)。改变输入电流频率和
励磁电压便获得各种转速[2]。在加速和制动过程中,通过改变电流频率进行加减速,
以防止电主轴温升过高。由于输入定子三相交流电的相序决定电机旋转磁场的方
向,所以改变电流的相序,就可以改变电主轴的旋转方向。
与传统机床主轴相比,电主轴具有如下特点[4]:
(1)结构紧凑,机械效率高,噪声低,热振动小,精度高等。
(2)主轴的 DmN值较高,可在额定转速范围实现无级调速。
(3)易于实现高速化加工,且动态精度和动态稳定性更好。
(4)矢量控制技术的运用,可以满足大转矩的输出要求,还可以实现精确的
主轴定位和 C轴传动功能。
(5)由于采用“零传动”,主轴运行更平稳,没有冲击,其寿命较长。
(6)机械结构简单,转动惯量小,快速响应性高。
高速电主轴的性能既直接决定了机床的超高速加工性能,影响数控机床整机
的技术水平,又制约着主机的发展速度。因此各工业发达国家都对高速电主轴的
研究与发展十分关注,因而研究高速主轴具有重要意义[5]。
由于电主轴蕴含着高技术,所以国际著名的电主轴厂商实行技术垄断。国家
必须深入研究其关键技术,开发具有我国自主知识产权的高速电主轴单元,以满
足数控机床快速发展的需要。通过研究开发并掌握高速电主轴的技术,可以减小
国内机械工业对国外先进机床的依赖,扭转国家在技术上受制于人、经济上价格
昂贵的被动局面,加速世界制造业的中心向国内转移的进程。
§1.2 国内外研究现状及发展趋势
§1.2.1 电主轴技术研究现状
20世纪60年代国内开始将电主轴应用于工业生产中,形成一定的生产规模,
但应用范围较窄,功率低且刚度小。20世纪70年代后期至80年代,成功研制了高
第一章 绪论
3
刚度、高速电主轴,被广泛应用于各个机械制造领域。90年代中后期,研制成功
铣用电主轴,高精度硅片切割机用电主轴的出现,进一步促进机械装备制造业的
发展[6]。
目前洛阳轴承研究所开发了额定转速从5000r/min至15000r/min、功率从0.2kW
至75kW的多个系列160余种电主轴产品;广州钜联高速电主轴有限公司研发的大
功率静压轴承电主轴曾获得日内瓦国际专利技术博览会金奖;广东工业大学高速
加工和机床研究所也开发了数控铣床高速电主轴,利用ANSYS有限元分析方法对
电主轴的动静态特性进行了分析,研究了电主轴的固有频率和振型等;安阳莱必
泰机械有限公司,拥有先进的电主轴、机床主轴设计和制造技术;大连机床公司
与德国阿亨(Aachen)大学共同研制开发的DHSC500高速加工中心;汉川机床有
限责任公司也先后研制出5.5kW 和15kW 的大功率电主轴,最高转速能达到
15000r/min。另外,国内高等院校也对电主轴进行了大量的研究,如大连理工大学、
北京工业大学、浙江大学等。据有关资料显示,国产电主轴所占份额还不足国内
市场总额的1/3,且大部为低档、低值部分。
国外高速电主轴技术已普遍应用到机械制造业中,技术水平也处于领先地位,
逐步形成了一系列标准产品,欧、美、日的电主轴技术代表了整个电主轴发展的
最高水平。美国福特公司和Ingersoll公司推出的HVM800卧式加工中心的65kW电主
轴,使用直线电机,最高转速达1.5×104r/min,从启动到达到极限转速的时间仅需
15s;瑞士DIXI公司的WAHLIW50型卧式加工中心,采用电主轴结构,主轴转速为
3×104r/min;日本三井精机公司生产的HT3A卧式加工中心,采用陶瓷轴承的电主
轴,主轴转速为4×104r/min;意大利Famup公司生产的精密机床用电主轴最大功率
达24千瓦,极限转速为3×104r/min,可以加工质量90千克、精度1.5微米的壳体零件;
德国CyTecsystemS公司生产的Cyspeed系列电主轴最高转速达4×105r/min(最大输
出功率为20千瓦)和最大输出功率为50千瓦(极限转速1000转/分)。目前,电主
轴的功率和品质不断得到提高,最大转速可达2×106r/min,直径范围33~300mm,
功率范围0.125~80kW,转矩范围0.02~300N·m。
§1.2.2 国内外高速电主轴技术的差距
与国外相比较,国内电主轴在性能、品种和质量都有较大差距,主要包括以
下方面[7,8]:
(1) 低速大转矩方面,国外电主轴低速段的输出转矩最大可达300N·m以上,
而国内目前仅在100 N·m以内。
(2) 高转速方面,国外的电主轴转速已达7.5×104r/min(如意大利的GAMFIOR
公司),我国则多在15000r/min 以下。
高速电主轴矢量控制方法的研究
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(3) 支承方面,国外高速精密主轴采用陶瓷球混合轴承、全陶瓷轴承、流体动
/静压轴承和磁悬浮轴承等;国内则多采用钢制轴承,少量采用采用陶瓷球混合轴
承,主要依赖进口,但工作寿命短得多。
(4) 轴承润滑方面,国外普遍采用可靠性好、对环境污染小的油气润滑技术,
而我国仍用油脂润滑或油雾润滑,制约着电主轴转速的提高。
(5) 精密加工与精密装配工艺方面,主轴、箱体、前后轴承盖等这些关键零件
必须进行精密加工或超精密加工,对同心度、垂直度和表面粗糙度有极严格的要
求。
(6) 配套技术也有较大差距,主轴电机矢量控制、交流伺服控制、精确定向、
快速启动、停止等技术,国内仍然不够成熟,甚至不能完全满足需要。
(7) 产品的品种、规格、数量和制造规模等方面,国产电主轴仍然处于小量研
发试制阶段,仍然主要从国外进口,远不能满足国内数控机床和加工中心发展的
需求。
(8) 调速控制方面,国外一些著名公司在进行理论研究的同时,先后推出了具
有各自特色的矢量型无速度传感器变频器。但是国内在这方面研究成果却很少,
无速度传感器控制的实用化还与国外产品差距很大,国产变频器大多还处在 V/F
控制水平。
§1.2.3 电主轴技术的发展趋势
随着机床技术的进步,对电主轴提出了更高的要求,其发展趋势主要表现在
以下几个方面[9]:
(1) 向电机内装式电主轴单元方向发展。采用带传动或直连式传动方式的机床
和技工中心会机构会变得复杂,同时速度的提高也产生振动,因此 8000r/min 以上
的设备多采用电主轴单元方式。由于结构等因素的影响,个别类型的机床如虚拟
(并联)机床、五面体加工中心等高档机床必须采用这种内装式电主轴。电机内
装式主轴单元已成为数控金属切削加工设备主轴系统技术发展的主要趋势。
(2) 向高速大功率、低速大转矩方向发展。实际应用中,大多数机床需要能够
同时满足能在同一台机床上进行高速精加工和低速重切削的要求。因此,要求电
主轴单元应具备高速大功率、低速大转矩的性能。意大利、瑞士、德国等制造商
生产的电主轴,最高转速可达到7.5×104r/min,功率一般在10~50KW,最大可达
65KW;而在低速大转矩方面,其研制的电主轴低速段的输出转矩可以达到200N·m
以上。
(3) 向高精度、高刚度和高可靠性方向发展。为了满足用户需要,要求数控机
床具有回转精度高和刚度好的性能,作为核心部件的电主轴的精度和可靠性的要
摘要:
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目录中文摘要ABSTRACT第一章绪论························································································1§1.1研究背景及意义········································································1§1.2国内外研究现状及发展趋势························································2§1.2.1电主轴技术研究现状····················...
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作者:牛悦
分类:高等教育资料
价格:15积分
属性:83 页
大小:3.09MB
格式:PDF
时间:2024-11-19