Compensation of unbalanced three-phase voltage supply in voltage source inverter

Analytical closed-form investigation of PWM inverter induction motor drive performance under DC bus voltage pulsation

“…The voltage ripple appearing across the dc link capacitor terminals contains, only even-order harmonics [2].…”

“…For this, we can use the relation between the Laplace and modified Z transforms [13]. Using (2) and its derivation dt=Tdε we can derive the Laplace transforms of the periodic waveform as:…”

“…So, the analysis of the dc-link voltage pulsation and its influence on the motor performances is of great importance. The dc-bus voltage pulsation is composed of several sources such as follows [3]: a) The diode rectification of the AC line voltage causes pulsation components [1] b) Unbalance in the AC power supply generates 100 or 120-Hz component [3] c) In some faulty conditions in the front-end rectifier dc link voltage may consist again pulsation [2] d) Transient voltage sags in the three-phase input line voltages can cause the rectifier stage to enter singlephase rectifier operation with corresponding dc-bus voltage pulsation [4].…”

Optimal Control of Input Rectifier in Voltage-Source Inverter Supplied from Unbalanced Power Grid

“…Series combinations of inductance and resistance are considered at the input terminals of the inverter. The control method described in [3,4] is considered throughout this paper. NUMERICAL SIMULATIONS First, analysis of properties of the compensating control method for the system where one of the line voltages is changed has been carried out.…”

“…The horizontal axis represents the angle and the vertical one the magnitude of the phasor of the positive-sequence component of the three switching functions. The detailed description of the variables in the applied control method can be found in [3]. For every particular point in the area fenced by the solid curve in the right hand side of the figure, a negativesequence component of the switching functions can be computed that eliminates the DC-link current pulsations and keeps the voltage in the DC bus constant in steady-state operation.…”