PEREC A list of PWM techniques 4 Triangular-wave sampling Natural sampling Uniform sampling 4 Calculation Calculation based on equal-area criterion Selective harmonics elimination 4 Hysteric control Space Vector Modulation(SVM, or SVPWM) 争 Random pwm
Power Electron cs i 6 A list of PWM techniques A list of PWM techniques Triangular Triangular-wave sampling wave sampling – Natural sampling Natural sampling – Uniform sampling Uniform sampling Calculation Calculation – Calculation based on equal Calculation based on equal -area criterion area criterion – Selective harmonic Selective harmonic s elimination elimination Hysteric control Hysteric control Space Vector Modulation (SVM, or SVPWM) Space Vector Modulation (SVM, or SVPWM) Random PWM Random PWM
PEREC 6.2 Some major PWM techniques 争 Natural sampling 命 Uniform sampling 4 Selective harmonics elimination 争 Some practical issues Synchronous modulation and asynchronous modulation Harmonics in the pwm inverter output voltages Ways to improve DC input voltage utilization and reduce switching frequency Connection of multiple pwm inverters 7
Power Electron cs i 7 6.2 Some major PWM techniques Some major PWM techniques Natural sampling Natural sampling Uniform sampling Uniform sampling Selective harmonics elimination Selective harmonics elimination Some practical issues Some practical issues – Synchronous Synchronous modulation and asynchronous modulation modulation and asynchronous modulation – Harmonics in the PWM inverter output voltages Harmonics in the PWM inverter output voltages – Ways to improve DC input voltage utilization and reduce Ways to improve DC input voltage utilization and reduce switching frequency switching frequency – Connection of multiple PWM inverters Connection of multiple PWM inverters
PEREC Triangular-wave natural sampling Uni-polar PWM in single-phase VSI R VD K本vD Control u Mudulation Carrier Carrier Uni-polar sampling is used to realize uni-polar PWm
Power Electron cs i 8 Triangular Triangular -wave natural sampling wave natural sampling Uni -polar PWM in single polar PWM in single -phase VSI phase VSI Uni -polar sampling is used to polar sampling is used to realize realize uni -polar PWM. polar PWM. Control signal Carrier Mudulatio n Carrier Ud + V1 V2 V3 V4 VD1 VD2 VD3 VD4 uo R L ur uc
PEREC Triangular-wave natural sampling Bi-polar PWM in single-phase VSI R L VD VD Control Mudulation Carrier Carrier 4 Bi-polar sampling is used to realize bi-polar PWM
Power Electron cs i 9 Triangular Triangular -wave natural sampling wave natural sampling Bi -polar PWM in single polar PWM in single -phase VSI phase VSI Control signal Carrier Mudulatio n Carrier Ud + V1 V2 V3 V4 VD1 VD2 VD3 VD4 uo R L ur uc Bi -polar sampling is used to polar sampling is used to realize bi realize bi -polar PWM. polar PWM