In this paper, an improved hybrid space vector pulse width modulation (HSVPWM) technique is proposed for IM (induction motor) drives. The basic principle involved in the proposed random pulse width modulation (RPWM) c...In this paper, an improved hybrid space vector pulse width modulation (HSVPWM) technique is proposed for IM (induction motor) drives. The basic principle involved in the proposed random pulse width modulation (RPWM) cuddled SVPWM is amalgamating the pre-calculated switching timings for various sections of hexagonal space vector boundary and the random selection of carrier between two triangular signals, in order to disband acoustic switching noise spectrum with improved fundamental component. The arbitrary selection between triangular carriers, which is decided by digital signal states (Low or High) of the linear feedback shift register (LFSR) based pseudo random binary sequence (PRBS) generator. The SVPWM offers a control degree of freedom in terms of positioning of vectors inside every sampling interval and hence it has six possible variants of the voltage vectors arrangements in each sector. The developed HSVPWM is thoroughly analyzed in using the MATLAB? based simulation for all SVPWM variants. From the simulation and experimental results viz. harmonic spectrum, harmonic spread factor (HSF), total harmonic distortion (THD) etc., and the superiority of the proposed scheme such as better utilization of DC bus and the randomization of the harmonic power are evidenced. For the practical implementation, Xilinx XC3S500E FPGA device has been used.展开更多
三相并网逆变器在新能源发电系统和电动汽车等领域起着重要的作用,为确保系统安全稳定运行,孤岛检测是十分必要的。对基于空间矢量控制的三相并网逆变器,传统的主动频移法(active frequency drift,AFD)不能直接应用,存在检测盲区的问题...三相并网逆变器在新能源发电系统和电动汽车等领域起着重要的作用,为确保系统安全稳定运行,孤岛检测是十分必要的。对基于空间矢量控制的三相并网逆变器,传统的主动频移法(active frequency drift,AFD)不能直接应用,存在检测盲区的问题,且施加的频率扰动量会对三相进网电流波形质量造成一定的影响。提出一种基于空间矢量脉宽调制(space vector pulse width modulation,SVPWM)控制三相并网逆变器的AFD孤岛检测方法,其对锁相环(phase-locked loop,PLL)计算出的相角施加扰动,但不属于主动移相法。分析孤岛检测盲区的成因以及消除盲区的可能性,并对施加扰动后的三相电流进行谐波分析,提出抑制谐波的改进半解耦控制算法,最后给出仿真和实验结果。展开更多
文摘In this paper, an improved hybrid space vector pulse width modulation (HSVPWM) technique is proposed for IM (induction motor) drives. The basic principle involved in the proposed random pulse width modulation (RPWM) cuddled SVPWM is amalgamating the pre-calculated switching timings for various sections of hexagonal space vector boundary and the random selection of carrier between two triangular signals, in order to disband acoustic switching noise spectrum with improved fundamental component. The arbitrary selection between triangular carriers, which is decided by digital signal states (Low or High) of the linear feedback shift register (LFSR) based pseudo random binary sequence (PRBS) generator. The SVPWM offers a control degree of freedom in terms of positioning of vectors inside every sampling interval and hence it has six possible variants of the voltage vectors arrangements in each sector. The developed HSVPWM is thoroughly analyzed in using the MATLAB? based simulation for all SVPWM variants. From the simulation and experimental results viz. harmonic spectrum, harmonic spread factor (HSF), total harmonic distortion (THD) etc., and the superiority of the proposed scheme such as better utilization of DC bus and the randomization of the harmonic power are evidenced. For the practical implementation, Xilinx XC3S500E FPGA device has been used.
