A Comparison And Relationship Between Sinusoidal Pulse Width Modulation(SPWM) And Space Vector Pulse Width Modulation(SVPWM) For Three-phase Inverters

With developments in solid-state power electronic devices and microprocessors,numerous pulse-width-modulation(PWM)techniques have been developed for industrial applications.For example,PWM-based three-phase voltage source inverters(VSI)convert DC power to AC power with variable voltage magnitude and variable frequency.This thesis discusses the advantages and disadvantages of two different PWM techniques: the sinusoidal PWM(SPWM)technique and the space-vector PWM(SVPWM)technique.By considering their ease of implementation and by analyzing the output their total harmonic distortion(THD),these two methods are compared.Both modualion techniques are examined with the same system parameters and inverter rating in order to obtain fair judgment.The simulation results show that SVPWM techniques have lower total harmonic distortion than the SPWM technique.The SVPWM technique is better than SPWM by its total harmonic distortion and less switching losses.The fundamental value for SVPWM is bigger than SPWM,which is nearly equal to the reference value.This thesis also discusses the relationship of SPWM and SVPWM by a comprehensive analysis.The relationship includes the modulation signals and space vectors,zero-sequence signal and the vector sectors,modulation signals and space-vector sectors,and the distribution of zero vectors and zero-sequence signal.From the relationship of SPWM and SVPWM,we can get that's the two methods of PWM can be equivalent in the distribution of zero sectors and zero-sequence signal.