A critical survey of techniques used in 3-phase carrier-based PWM to lower the current distortion

Pulse Width Modulation of Three Phase Inverters Based on Linear Programming

“…Fig. 7 illustrates the waveform of the slack variable 𝑣 𝑠 (magenta), used as the minimization objective (5). It corresponds to the maximum absolute value of all leg voltages and, in the same time, it defines a minimum dclink value (𝑉 𝑑𝑐 ) needed to generate the actual voltage vector demanded by an upper control loop.…”

“…From this point of view, the desired voltage vector components 𝑉 𝛼 * , 𝑉 𝛽 * are known variables and they build the vector b in the equality constraint 𝐴𝑥 = 𝑏 in (5). The matrix A is given by the Clarke's transform (6) and the unknown vector x contains searched leg voltages:…”

“…The solution has to be found in the feasible regioninside of a complex polytope (Fig. 5), specified by the constraints (5). Whereas the simplex method travels along the constraints (vertices), the interior-point methods go through the inside of the feasible space.…”

“…In applications with delta-connected load or in those, where the centre of star-connected load is insulated, it is possible to increase the output voltage using zero-sequence component which introduces a degree of freedom to the system. The zero-sequence component is exploited by traditional space-vector PWM method (SVPWM) [1][2][3][4] and by many carrier-based PWM methods [3,[5][6][7][8][9]. These techniques have been an intense research topic for several decades.…”