变频器和滤波器 分类和应用

变频器.失真. 变频器.谐波失真. 变频器.电磁干扰.(噪声) 附件 I. Norm UNE-EN 61800-3/A11:2002 变频器和滤波器应用范围 目录 变频器.失真. 变频器.谐波失真. 变频器.电磁干扰.(噪声) 附件 I. Norm UNE-EN 61800-3/A11:2002 附件 II. 滤波器摘要.

变频器失真 1

我们分析他们的形成和采用不同的方法减少它们, 特别是采用不同的滤波器. Variable Speed Drives DISTORTIONS 变频器造成的失真 变频器造成的失真只要有以下两类: 谐波失真: 产生于 整流桥. 电磁噪声: 产生于 逆变器. 我们分析他们的形成和采用不同的方法减少它们, 特别是采用不同的滤波器.

变频器 谐波失真 2

Variable Speed Drives DISTORTIONS 谐波失真 什么是“谐波”? 现已证实任何周期的波形 (方波,三角波, …) 都可以由不同相序和频度的正弦波叠加而成. 所有这些下弦波就组成了谐波的分量. » Harmonic content of a squared wave

Variable Speed Drives DISTORTIONS 谐波失真 输入谐波电流会产生哪些影响? 谐波增加了导电体和变压器的RMS值，这“额外”的电流值是不真实的（它不能工作），但是因为这个电流，变压器和导线都必须增加截面积来阻止导体的过热影响。 输入电压波形失真，能产生以下重要影响： 它能影响使用单相电压的设备比如计算机和其它的低压设备. 对设备分发系统产生不需要的共振.

Variable Speed Drives DISTORTIONS 谐波失真 输入谐波电流的影响？ 功率因素下降. 变压器.电线.等的过载 … 功率因素修正电容的过载.

Variable Speed Drives DISTORTIONS 谐波失真 怎样补偿输入谐波失真? 输入电抗器又称电抗感应器.可置于整流桥输入端，实现以下两个功能: 一方面保护整流桥，免于受电网电压波动的影响. 另一方面, 他们过滤掉谐波， 使电流正弦波平滑. 他们也可置于直流总线. 但此方案使整流桥得不到相应的保护, 但此方案不失为一个低成本的方案. 使用有源谐波滤波器. 他们分析变频器产生的谐波分量 ，同时产生极性相反的谐波分量与之相互抵消.

Variable Speed Drives DISTORTIONS 谐波失真 怎样补偿输入谐波失真? 安装12脉冲系统. 如果我们把整流桥分成两个整流桥输入 每个整流桥输入电压互相错开30度相位角, 在理论上11次以下的谐波分量将得到有效的控制. 因此，变压器需要有两个副边，一个是星连接，一个是三角连接。 负载的一半将由第一个副边提供 ,剩下的由第二个副边提供， 他们产生相差 30º 相位角的电流. 这可以很容易看到 5th and 7th 谐波完全消失.

Variable Speed Drives DISTORTIONS 谐波失真 12 脉冲整流系统.

Variable Speed Drives DISTORTIONS 谐波失真 12 脉冲整流系统. 当整流桥导通时，输入电压比总线电压高. 输入电抗器避免了完全充电并且使波形更加平滑，得到适合的方形波.

Variable Speed Drives DISTORTIONS 谐波失真 12 脉冲整流系统. 我们可以假设一个理想的整流系统, 假设一些方波信号输入作为参考. 考虑有两个副边输入, 解释如前, 输入两相差 30º 相位电流给整流器, 结果就是一个更平滑的电流提供给逆变部分:

变频器 电磁干扰（噪声） 3

Variable Speed Drives ELECTRIC INTERFERENCES (NOISE) 电磁噪声 电磁噪声产生于逆变桥. 当晶体管换向的时候，会干扰电流信号 (switch over ON and OFF and vice versa). 正是由于此，电磁噪声是一个高频的电流信号， 耦合变频器与电机之间的电流，同时也会产生幅射. 处理以下两方面的干扰是很有必要的: 内部信号传导 外部信号幅射

Variable Speed Drives ELECTRIC INTERFERENCES (NOISE) RADIATED EMI 电磁噪声幅射可以通过以下方法来解决: 使用金属导体共地. 使用屏蔽电缆. 变频器本身的金属外壳. » Power wires screened

Variable Speed Drives ELECTRIC INTERFERENCES (NOISE) CONDUCED EMI 噪声内部信号传导干扰可以通过以下两种途径来解决: 噪声耦合到变频器输入信号 推荐使用 RFI 输入滤波器 (射频干扰) 也称 EMC 滤波器 (电磁兼容). Regulation which controls the selection of these filters is UNE-EN 61800-3/A11:2002. See details on Annex I.

Variable Speed Drives ELECTRIC INTERFERENCES (NOISE) CONDUCED EMI 噪声内部信号传导干扰可以通过以下两种途径来解决: 噪声耦合到电机电流. 使用输出共模滤波器, 假设相关噪音为共模噪音，也就是说噪音信号相连的存在于相与地之间和电机绕组与大地之间的电容。这噪音对轴承存在危害。 使用 dV/dt 输出滤波器, in case of the coupled noise is differential noise, that means, noise signal coupled to the capacitances existing between phases. This noise will produce isolation drillings and additionally will increase the dV/dt factor. These filters can be:假设相关噪音为微分噪音，也就是说，通过线间电容 Output Inductance (output coils in series, one per phase) Iron Dust Toroids, in all output phases.

Variable Speed Drives ELECTRIC INTERFERENCES (NOISE) dV/dt滤波器的功能 可以检测到变频器输出波形如下: This is the result of the inverter bridge action. Show film

Variable Speed Drives ELECTRIC INTERFERENCES (NOISE) dV/dt滤波器的功能 若把波形放大, 可以看到波形的角度并非 90º 直角: Drive dV/dt Losses 132kW 800V/µs 1380W 132kW 4000V/µs 1100W

Variable Speed Drives ELECTRIC INTERFERENCES (NOISE) dV/dt滤波器的功能 通过增加 dV/dt 斜坡可以的减少变频器损耗, 这样就充许变频器损耗更小的功率，因此他们的更小 Drive dV/dt Losses 132kW 800V/µs 1380W 132kW 4000V/µs 1100W 增大dV/dt斜坡这种方法最大的危害就是： 会在变频器输出端产生尖锐的过脉冲电压， 此电压远远高过电机输出. 此电压可以通过跟其他品牌变频器比较而对比出来: » Actual measurement on competitor drive of 200A on load

Variable Speed Drives ELECTRIC INTERFERENCES (NOISE) dV/dt滤波器的功能 为解决此问题, Power Electronics研究出 IGBTs的门极电阻, 保证尖峰脉冲不超过限值. » Actual measurement on a drive of 200A on load: Competitor Rg 门极电阻 ，控制负载的 “电容量” 使之与 IGBT一致. » Actual measurement on a drive of 200A on load: POWER ELECTRONICS

Variable Speed Drives ELECTRIC INTERFERENCES (NOISE) dV/dt滤波器的功能 Power Electronics变频器, 集成了 dV/dt 输出滤波器. 此滤波器, 前面解释过, 由线圈组成, 串联在输出端，它执行着过滤尖峰脉冲的作用. The result: 3rd Level: Filters 2nd Level: Cooling 1st Level: Electronic Inductances Power Supply dV/dt Filter RFI Filters » Actual measurement on a drive of 200A on load: POWER ELECTRONICS

Variable Speed Drives ELECTRIC INTERFERENCES (NOISE) CONDUCED EMI 最后, 需有一个滤波器 处理由斩波信号转换成 正弦波信号: 这就是 Sinusoidal Output Filter (LC电路在变频器输出端). 噪声依赖于电容和dV/dt因素.电容在安装时是可变量 . dV/dt 依赖于变频器. 若 dV/dt 减小到可以几乎忽略的情况下, 噪声也就几乎消失了. The result:

Annex I Norm UNE-EN 61800-3/A11:2002 4

Annex I ELECTRO-MAGNETIC COMPATIBILITY NORM UNE-EN 61800-3/A11:2002 Limits application in the measurement of the Conduced Perturbations Nowadays exist several norms about EMC according to the 89/336/EEC directive that refer to the variable speed drive or to those equipments incorporating drives. Specific norms for drives UNE-EN 61800-3/A11:2002: Adjustable speed electrical power drive systems. Part 3: EMC product standard including specific test methods.

Annex I ELECTRO-MAGNETIC COMPATIBILITY NORM UNE-EN 61800-3/A11:2002 Norm Classifying Criteria Application Limit First environment Non restricted distribution Limit 1 Restricted distribution Limit 2 Second environment Input current  100A Limit 3 Input current > 100A Limit 4 Where: First Environment: Includes domestic or residential use. It includes also, places directly connected, without intermediate transformers, to a power supply distribution system of low energy which additionally gives supply to buildings used for domestic uses (cinemas, theatres, shopping centres, hospitals,…). Second Environment: (Named also industrial). It includes all places different from those which are directly connected to a power supply distribution system of low energy which additionally gives supply to buildings used for domestic uses (factories and facilities supplied with transformer of medium voltage to low voltage).

Annex I ELECTRO-MAGNETIC COMPATIBILITY NORM UNE-EN 61800-3/A11:2002 Norm Classifying Criteria Application Limit First environment Non restricted distribution Limit 1 Restricted distribution Limit 2 Second environment Input current  100A Limit 3 Input current > 100A Limit 4 Where: Non-Restricted Distribution: Marketing modality where the power supply of the drive does not depend on the customer or user regarding to EMC issues for the application of operation. Restricted Distribution: Marketing modality where the manufacturer limits the supplying of the drive to those customers or users which, in an independent or together way, have technical competence on the EMC requirements for the application of operation.

Annex II Filters Summary 5

Annex II FILTERS SUMMARY FILTER TYPES Summarizing: 无源滤波器: 输入电抗器 (阻抗感应器) 直流感应器 谐波失真 三相输入感应器 有源滤波器 金属导电 幅射噪声 屏蔽电缆 金属外壳屏蔽 EMC 滤波器 (or RFI filter). 过波耦合输入电流信号噪声 输出共模滤波器. 过滤流经马达的电磁噪声. 电磁噪声 Output Inductances in series (1 per phase) dV/dt 滤波器 (differential mode noise) 传导噪声 Iron Dust Toroids (1 per phase) 正弦波输出滤波器 (LC circuit)

谢谢！ Presentation Realized Organized VARIABLE SPEED DRIVES AND FILTERS Classification and Application Realized Pilar Navarro Organized Marketing Department www.power-electronics.com ©2006 Power Electronics, S.L.