变频器原理介绍分析.ppt

变频器原理介绍 * . AC Drive Basics Types of frequency converters 变频器的类型 Current controlled frequency converters 电流控制型变频器 Voltage controlled frequency converters 电压控制型变频器 Structure of an AC drive 交直交交流传动的结构 U line U d U 2 at 1/2 f max U 2 at f max U line U d U 2 U1 V1 W1 M 3 Motor V1 V3 V5 V2 V6 V4 - U d L1 L2 L3 4 1 2 3 L, choke + R, charging resistor Line converter (Rectifier) 整流器 DC link (Intermediate circuit) 中间回路 Inverter 逆变器 Control electronics 控制回路 20KW以下 交直交变频器电原理图 20KW~30KW 交直交变频器电原理图 40KW~90KW 交直交变频器电原理图 110KW~355KW 交直交变频器电原理图 Controls in the software of an AC drive 交流传动中的软件控制示意图 Inverter Inverter control Motor control Process control PI, PID M 工艺过程 Hardware PWM- modulation (DTC: switching logic) T, n, Fref U, f power, torque, 速度反馈 物理量实际值 y speed (switching orders) External references: T, n,Fref E.g. PFC-macro scalar, vector (DTC:motor model) ref symbols transfer function operational amplifier Process control: Part of the AC drive controls 变频器实现过程控制: 交流传动控制功能之一 给定值 实际值 PID L M 3 Ref. Motor control: Scalar control 电机控制方式:标量控制 Actual Frequency reference modulator = 3~ Process control PI PWM Uref fref Reference U f fref U/f-curve Application Macros Motor control: Vector control 电机控制方式: 矢量控制 Speed control PI Torque reference Speed reference Torque reference and selector Modulator Voltage Current = Motor model Torque control 3~ Act. torque Measured speed PWM Flux control Uref fref Angle of rotor Act. flux Flux reference Flux reference Motor control: DTC 电极控制方式: 直接转矩控制 Speed control PID REF Torque reference Torque Reference Selector Speed reference Switching logic Switch positions Voltage Current = Motor model Torque and flux comparator 3~ Torque Flux Calculated speed U 2 U1 V1 W1 M 3 Motor V1 V3 V5 V2 V6 V4 - + U 2 U 2 Converter control: PWM 脉宽调制波形图 Load type:Constant torque 恒转矩型负载 F = m*g T = constant F = constant T = F*d/2 d/2 Load and counterload have the equal weight line Elevator, conveyor, crane etc. 升降机, 传送带, 起重机 Load t