New high-performance thyristor gate control set for line-commutated converters

A Nonlinear Approach for Assessing Stability in Line-Commutated Converters With an Integrating Controller

“…Since K = 1 R i C i , preset R i = 250 kΩ adjusts the loop gain. A fast, high precision thyristor digital gate controller (TGC) is used to generate and to distribute the firing pulses [19]. The oscillograms obtained for different operating points represent the reference voltage α R (t), the output voltage v o (t), and the control signal α(t), which is shown inverted respect to Fig.…”

“…where α ∈ (α min , α max ) is the firing angle, 0 < α min < α max < π, p is the pulse number, i.e., the number of firing states in a line period and E MAX is the maximum instantaneous output voltage. The firing time is obtained from the comparison between a control signal α(t) and a grid-synchronized ramp r(t) [19]. In order to obtain a null steady-state error for an input step, an integrating controller is commonly applied to the voltage error.…”

Phase-controlled line-commutated converter control in discontinuous conduction mode

“…In applications requiring the highest possible bandwidth and maximum disturbance rejection, the transfer function in CCM can be easily linearized achieving a constant gain K in digital implementations by using a look-up table (LUT) [2,3]. Due to the voltage source characteristic of the PCTC in CCM, this table is independent of the load.…”

Method for Discontinuous Current Mode Compensation of Line-Commutated Converters

“…An average output voltage (v th 1 , v th 2 , v th 3 ) and a decreasing output current (i L 1 , i L 2 , i L 3 ) are also illustrated by solid lines. Let us assume that the small-signal gain of the converter could ideally be linearized, achieving [16] v th = KV α (1) where V α is a control signal and v th is the average output voltage. Assuming that both V α and voltage v c remain constant, the average output current can be approximated as follows:…”