Single-phase serial AC voltage controller based on bipolar PWM AC matrix-reactance chopper

AC Voltage Sag-Swell Compensator based on Unified NonInverting and Inverting Output Voltage AC Chopper

“…It is observed that the voltage stresses for switches S 1 and S 2 are equal to the input voltage, whilst S 3 and S 4 experience approximately twice the input voltage as in (4). Hence, the voltage stresses of the proposed UNI-AC are reduced compared to the schemes in [8][9][10], where the voltage stresses on power switches can reach more than three times the input voltage if duty cycle d=0.3. From Figure 6, it is concluded that the output voltage can be both in-phase and out-phase relative to the input voltage, according to duty cycle variation.…”

“…According to (1), the output capacitor voltage v o can be calculated from (3) and, thus, the voltage stress on S 3 and S 4 is expressed in (4). It is found that the extended output voltage range is maintained and that lower voltage stresses for the power switches are achieved compared to those in [8][9][10], especially when the duty cycle is small to generate out-phase voltage. Despite the proposed UNI-AC having twice the number of switches, this does not increase the total semiconductor device cost, due to the reduced voltage stress per device.…”

“…The bipolar AC chopper with inner voltage boosting cell and smooth bidirectional output voltage gain curve has been presented, as shown in Figure 1 [10]. It is also able to maintain a common ground for input and output ports.…”

“…Therefore, both voltage sag and swell can be compensated adaptively when the proposed converter is applied as a DVR in the utility. The UNI-AC topology is expected to have a reduced footprint (higher power density) and a more compact design than the solution in [10].…”

Modelling of voltage transfer function of the three-phase hybrid transformers with voltage or current source matrix converter

“…In the known publications, there are presented various types of AC/AC voltage sag/swell compensators that mitigate the unwanted effects on supply [6]- [32]. These compensators contain: (i) conventional transformer (electromagnetic coupling) with tap changer [6], [7], (ii) AC/AC thyristor controller [8], (iii) PWM matrix choppers (MC) and PWM matrix reactance choppers (MRC) with or without a series addition transformer, [8]- [14], (iv) AC/DC/AC converters as the dynamic voltage controllers (DVR) with DC storage and a series addition transformer [15]- [21]. In addition there are, (v) hybrid transformers (HT) with a conventional transformer (electromagnetic coupling) and MC or MRC (electrical coupling), which have recently been intensively developed [22]- [32].…”