matlab第四章(改)

1、电气工程仿真与计算电气工程仿真与计算Electrical Engineering Simulation and Computation电气工程与自动化学院电气工程与自动化学院EESCChapter 4 电力电子应用技术电力电子应用技术Power Electronics Application EESC4.1 Power Electronic Device4.1.1 Diode（二极管）（二极管） The diode is a semiconductor device that is controlled by its own voltage Vak and current Iak. When

2、a diode is forward biased (Vak 0), it starts to conduct with a small forward voltage Vf across it. It turns off when the current flow into the device becomes 0. When the diode is reverse biased (Vak 0). The pulse height must be greater than 0 and last long enough to allow the thyristor anode current

3、 to become larger than the latching current Il.Characteristic CurveEESCnThyristor Model in Simulink The Thyristor block has two input ports (a: anode, g: gate) and two output ports (k:cathode, m: measure- ment). It also contains a series Rs-Cs snubber circuit that can be connected in parallel with t

4、he diode device . 4.1 Power Electronic DeviceEESC4.1 Power Electronic Device The thyristor model is simulated as a resistor Ron, an inductor Lon, and a DC voltage source representing the forward voltage Vf, connected in series with a switch. The switch is controlled by a logical signal depending on

5、the voltage Vak, the current Iak, and the gate signal g.EESC4.1 Power Electronic DevicenParameter ConfigurationResistance Ron： 内阻内阻Inductance Lon ：内感：内感Forward voltage Vf: 正向管压降正向管压降Latching Current I1: 闭锁电流闭锁电流Turn-off Time Tq: 关断时间关断时间Initial current Ic：初始电流：初始电流Snubber resistance Rs：缓冲电阻：缓冲电阻Snub

6、ber capacitance Cs：缓冲电容：缓冲电容 EESC4.1 Power Electronic DevicenExpample for Thyristor Single-Phase Halfwave RectifierEESC4.1 Power Electronic DevicenSimulation Parameters Parameters of Thyristor： Ron=0.001, Lon=0H, Vf=0.8V, Rs=20, Cs=4e-6F RL Load： R=1, L=0.01HEESC4.1 Power Electronic DevicenSimulatio

7、n Results EESC4.1 Power Electronic Device4.1.3 GTO（Gate Turn off Thyristor, 可关断晶闸管）可关断晶闸管） The gate turn off (GTO) thyristor is a semiconductor device that can be turned on and off via a gate signal. Like a conventional thyristor, the GTO thyristor can be turned on by a positive gate signal (g 0). H

8、owever, unlike the thyristor, which can be turned off only at a zero crossing of current, the GTO can be turned off at any time by the application of a gate signal equal to 0.Characteristic CurveEESCnGTO Model in Simulink The GTO block has two input ports (a: anode, g: gate) and two output ports (k:

9、cathode, m: measure- ment). It also contains a series Rs-Cs snubber circuit that can be connected in parallel with the diode device . 4.1 Power Electronic DeviceEESC4.1 Power Electronic Device The GTO model is simulated as a resistor Ron, an inductor Lon, and a DC voltage source representing the for

10、ward voltage Vf, connected in series with a switch. The switch is controlled by a logical signal depending on the voltage Vak, the current Iak, and the gate signal g.EESC4.1 Power Electronic DevicenParameter ConfigurationResistance Ron： 内阻内阻Inductance Lon ：内感：内感Forward voltage Vf: 正向管压降正向管压降Current

11、10% fall time: 电流下降时间电流下降时间Current tail time: 电流拖尾时间电流拖尾时间Initial current Ic：初始电流：初始电流Snubber resistance Rs：缓冲电阻：缓冲电阻Snubber capacitance Cs：缓冲电容：缓冲电容 EESC4.1 Power Electronic Device4.1.4 IGBT（Insulated Gate Bipolar Transistor, 绝缘栅极晶体管）绝缘栅极晶体管） The IGBT block implements a semiconductor device control

12、l-able by the gate signal. It turns on when the collector-emitter voltage is positive and greater than Vf and a positive signal is applied at the gate input (g 0). It turns off when the collector-emitter voltage is positive and a 0 signal is applied at the gate input (g = 0).Characteristic CurveEESC

13、4.1 Power Electronic Device Turn off Characteristic of IGBT The turn off characteristic of the IGBT is approximated by two segments. When the gate signal falls to 0, the collector current de-creases from Imax to 0.1 Imax during the fall time (Tf), and then from 0.1 Imax to 0 during the tail time (Tt

14、). The IGBT device is in the off state when the collector-emitter voltage is negative. Note that many commercial IGBTs do not have the reverse blocking capability. Therefore, they are usually used with an antiparallel diode.EESCnIGBT Model in Simulink The IGBT block has two input ports (C: Collector

15、, g: gate) and two output ports (E: Emitter, m: measure- ment). It also contains a series Rs-Cs snubber circuit , which is connected in parallel with the IGBT device (between terminals C and E). 4.1 Power Electronic DeviceEESC4.1 Power Electronic Device The IGBT is simulated as a series combination

16、of a resistor Ron, inductor Lon, and a DC voltage source Vf in series with a switch controlled by a logical signal (g 0 or g = 0)EESC4.1 Power Electronic DevicenParameter ConfigurationResistance Ron： 内阻内阻Inductance Lon ：内感：内感Forward voltage Vf: 正向管压降正向管压降Current 10% fall time: 电流下降时间电流下降时间Current ta

17、il time: 电流拖尾时间电流拖尾时间Initial current Ic：初始电流：初始电流Snubber resistance Rs：缓冲电阻：缓冲电阻Snubber capacitance Cs：缓冲电容：缓冲电容 EESC4.1 Power Electronic DevicenExpample for IGBT Boost Chopper Schematic DiagramEESC4.1 Power Electronic DevicenExpample for IGBT Boost ChopperEESC4.1 Power Electronic DevicenSimulation

18、Parameters IGBT： Ron=0.001, Lon=0H, Vf=1V, Tf=10e-6, Tt=20e-6, Rs=10, Cs=0.1e-6F Load： 50 Capacitor： 100e-6F Switch Period：2e-4s Duty Ratio： 0.6EESC4.1 Power Electronic DevicenSimulation Results EESC4.2 Rectifier and Simulation 4.2.1 Topology of Three Phase Rectifier Using Thyristor EESC4.2 Rectifie

19、r and Simulation 4.2.2 Three Phase Rectifier Simulation Model EESC4.2 Rectifier and SimulationnRectifier in Simulink Universal BridgenThe Universal Bridge block implements a universal three-phase power converter that consists of up to six power switches connected in a bridge configuration. It is the

20、 basic block for building two-level voltage-sourced converters (VSC).nThe type of power switch and converter configuration are selectable from the dialog box. Diodes and thyristors are naturally commutated power electronic devices, GTOs, IGBT and MOSFETs forced-commutated devices .EESC4.2 Rectifier

21、and SimulationnParameter ConfigurationNumber of bridge arm： 桥臂数桥臂数Snubber resistance Rs： 缓冲电阻缓冲电阻Snubber capacitance Cs：缓冲电容：缓冲电容Power Electronic device：器件：器件Ron： 内阻内阻Lon ：内感：内感Forward voltage Vf: 正向管压降正向管压降EESC4.2 Rectifier and SimulationnRectifier in Simulink Universal BridgeEESC4.2 Rectifier and

22、SimulationnRectifier in Simulink Universal BridgeEESC4.2 Rectifier and SimulationnHow to specify the Rs and Cs snubber values?nIn order to avoid numerical oscillations when your system is discretized, Rs and Cs snubber values need be specified for diode and thyristor bridges. nIf firing pulses to fo

23、rced-commutated devices (GTO, IGBT, or MOSFET) are blocked, only antiparallel diodes operate, and the bridge operates as a diode rectifier. In this condition appropriate values of Rs and Cs must also be used. EESC4.2 Rectifier and SimulationnHow to specify the Rs and Cs snubber values?nThese Rs and

24、Cs values are derived from the following two criteria: nThe snubber leakage current at fundamental frequency is less than 0.1% of nominal current when power electronic devices are not conducting. nThe RC time constant of snubbers is higher than two times the sample time Ts. These Rs and Cs values th

25、at guarantee numerical stability of the discretized bridge can be different from actual values used in a physical circuit. EESC4.2 Rectifier and SimulationnSynchronized 6-Pulse Generator The Synchronized 6-Pulse Generator block can be used to fire the six thyristors of a six-pulse converter. The out

26、put of the block is a vector of six pulses individually synchronized on the six thyristor voltages. The pulses are generated alpha degrees after the increasing zero crossings of the thyristor commutation voltages.EESC4.2 Rectifier and Simulation The pulse ordering at the output of the block correspo

27、nds to the natural order of commutation of a three-phase thyristor bridge. EESC4.2 Rectifier and Simulation The figures below display the synchroni-zation of the six pulses for an alpha angle of 0 degrees. The pulses are generated exactly at the zero crossings of the three line-to-line synchronizati

28、on voltages. EESC4.2 Rectifier and Simulation The Synchronized 6-Pulse Generator block can be configured to work in double-pulsing mode. In this mode two pulses are sent to each thyristor: a first pulse when the alpha angle is reached, then a second pulse 60 degrees later, when the next thyristor is

29、 fired. EESC4.2 Rectifier and SimulationnParameter ConfigurationnFrequency of synchroni-zation voltage: 同步电压频率同步电压频率nPulse width：脉冲宽度：脉冲宽度nDouble pulsing：双脉冲模式：双脉冲模式EESC4.2 Rectifier and SimulationnSimulation Parameters and Result Load: R=1ohm, L=1mH, E=-5VEESC4.3 PWM Inverter and Simulation 4.3.1 T

30、he Principle of PWM Inverter Single Phase PWM InverterEESC4.3 PWM Inverter and Simulation 4.3.2 Single Phase PWM Inverter nSimulation Model EESC4.3 PWM Inverter and SimulationnPWM GeneratornGenerator Mode: 发生器方式发生器方式nCarrier Frequency：载波频率：载波频率nModulation Index：调制度：调制度nFrequency of Output Voltage: 输

31、出电压频率输出电压频率nPhase of Output Voltage: 输出电压相位输出电压相位EESC4.3 PWM Inverter and SimulationnGenerator Mode： n1-arm bridge（2 pulses）n2-arm bridge（4 pulses）n3-arm bridge（6 pulses）ndouble 3-arm bridge（12 pulses）* Twelve pulses are generated for a double three-arm bridge. The first six pulses (1 to 6) fire the

32、 six devices of the first three-arm bridge and the last six pulses (7 to 12) fire the six devices of the second three-arm bridge. EESC4.3 PWM Inverter and SimulationnCarrier-2 Pulses： EESC4.3 PWM Inverter and SimulationnCarrier-6 Pulses： EESC4.3 PWM Inverter and SimulationnModulation Index：nThe Modu

33、lation index parameter is visible only if the Internal generation of modulating signal (s) parameter is selected. nThe amplitude of the internal sinusoidal modulating signal. The Modulation index must be greater than 0, and lower than or equal to 1. This parameter is used to control the amplitude of

34、 the fundamental component of the output voltage of the controlled bridge. Peak Value of Phase Voltage=MVdcEESC4.3 PWM Inverter and SimulationnParameter ConfigurationEESC4.3 PWM Inverter and SimulationnSimulation ResultsEESC4.4 DC Chopper and SimulationnChoppernBoost Chopper（升压斩波器）（升压斩波器）nBuck Chopper（降压斩波器）（降压斩波器）nBoost-Buck Chopper（升（升-降压斩波器）降压斩波器） EESC4.4 D