摘要
针对现有PWM(pulse width modulation)过调制算法复杂的问题,构建一种新型的准正弦平顶调制波,通过优化使所含基波显著提升、低次谐波影响最小。用三角载波采样,在线性区改变调制波高即可线性地改变PWM基波值,在过调制区则扩大调制波的平顶宽度并保持其高度不变,继续提升PWM基波,直至方波模式。为保持过调制区基波值与调制度M间的线性关系,将平顶宽与M的关系预先制表,通过查表法获取相应值。新技术PWM算法简单,且在线性区内的最大基波幅值比SPWM(sinusoidal pulse width modulation)高19%。在相同载波比N=33的情况下,其电流谐波总失真度在M∈[0.55,1]区间低于SPWM;在M∈[0,0.55]区间高于SPWM,但最大增加值小于2.2%。实验结果证实了新技术的有效性和优越性。
A new type of flat top quasi-sinusoidal modulation wave was designed and optimized to solve the complexity issue in the existing pulse width modulation （PWM） overmodulation algorithm.The technique increase fundamental amplitude,at the same time minimizes the low-order harmonic influence.It samples the modulating wave with a triangular carrier wave,and linearly changes PWM fundamental component amplitude through changing the modulating wave height in the linear range.In the overmodulation range,it continuously increases the fundamental component amplitude till approaching a square wave by broadening the flat top width of modulating wave while maintaining the maximum height as a constant.To maintain linearity between fundamental component amplitude and modulation index M in overmoudulation range,a lookup table including the flat top width and M relationship was pre-programmed into a microprocessor for real time implement.The new PWM algorithm is simple.Compared with sinusoidal pulse width modulation （SPWM）,the technique produces 19％ higher maximum fundamental component amplitude in linear modulation range ; its total harmonic current distortion is lower at M ∈ [0.55,1],and slightly higher at M ∈ [0,0.55] but the increase is less than 2.2％ under the same carrier wave frequency ratio N =33 condition.The new technique was validated with experiment results.
出处
《电机与控制学报》
EI
CSCD
北大核心
2014年第6期9-14,共6页
Electric Machines and Control
基金
福建省工业科技重点项目基金(2012H0022)
关键词
过调制
调制波
最大输出基波幅值
谐波计算
PWM算法
调制度
overmodulation
modulating wave
maximum fundamental component amplitude
harmonic calculation
PWM algorithm
modulation index
