Shyh-Shing Perng

A novel single-phase soft-switching unipolar PWM shunt active power filter

This paper proposed a novel single-phase soft-switching unipolar PWM active power filter (SSUPAPF). The proposed active power filter uses a simple auxiliary resonant circuit. The main switches of high-frequency arm operate at zero-voltage- switching (ZVS) turn-on. Also, the auxiliary switches operate at zero-current-switching (ZCS) turn-off. The main switches of low-frequency arm operate at 60Hz to reduce switching losses. Moreover, a unipolar PWM strategy is used for the proposed SSUPAPF. This strategy results in a better input current waveform than for the bipolar PWM strategy. The advantages of the proposed SSUPAPF are found in efficiency improvement, reduced the voltage stresses, and greatly reduced EMI. Furthermore, the proposed active power filter achieves a unity power factor and a sinusoidal line current. Finally, some experimental results are presented for demonstration.

A novel single-phase soft-switching unipolar PWM rectifier

This paper proposed a novel single-phase soft-switching unipolar PWM rectifier (SSUPR) using a simple auxiliary resonant unit. All main switches of high-frequency arm operate at zero-voltage-switching (ZVS) turn-on, while the auxiliary switches operate at zero-current-switching (ZCS) turn-off. All main switches of low-frequency arm operate at 60 Hz to greatly reduce switching losses. Moreover, a soft-switching unipolar PWM strategy is used for the proposed soft-switching rectifier. This strategy results in a better input current waveform than for the bipolar PWM strategy. Furthermore, the proposed rectifier achieves a near unity power factor, sinusoidal input current and a bidirectional power flow capability. Some simulation results of the proposed SSUPR, rated 400 W and operated at 40 kHz, are presented for verification.

A soft-switching single-phase three-arm dynamic voltage restorer

This paper presents a soft-switching single-phase three-arm dynamic voltage restorer which aimed at solving voltage disturbances such as voltage swell, voltage sag, over-voltage and under-voltage. The proposed scheme is composed of a three-arm topology which operates as a rectifier and an inverter. Rather than the conventional four-arm topology, the proposed three-arm topology not only reduces the number of main switches but also increases the system reliability and simplifies the control circuits. Moreover, using simple resonant units, all main switches of high-frequency arm are operated at zero-voltage-switching (ZVS) turn-on, while all auxiliary switches are operated at zero-current-switching (ZCS) turn-off. Finally, some simulation results are presented for verification.

Analysis and implementation of a three-phase soft-switching inverter

The system analysis and circuit implementation of a reduced parts three-phase soft-switching inverter (THSSI) comprising four main switches and four auxiliary switches is proposed in this paper. All main switches in the proposed THSSI operate at zero-voltage-switching (ZVS) turn-on, while the auxiliary switches operate at zero-current-switching (ZCS) turn-on and turn-off. Since the control circuits and the auxiliary circuits are thereby reduced to two sets, the reduction in the number of main switches can also increase the reliability. Thus, the proposed power converter configuration achieves fewer switching components and higher efficiency. Additionally, the dedicated control circuit required for soft-switching inverter operation is implemented using a FPGA circuit, reducing overall system cost and complexity. Some experimental results for a 500 W prototype are provided to demonstrate the theoretical analysis and system performance.

A soft-switching single-phase three-arm unified power quality conditioner

This paper presents an FPGA-based control circuit for controlling the soft-switching single-phase three-arm unified power quality conditioner (UPQC). The proposed soft-switching UPQC employs three-arm topology and uses simple resonant units. All main switches of the high-frequency arm operate at zero-voltage-switching (ZVS) turn on, while the auxiliary switches operate at zero-current-switching (ZCS) turn off. Moreover, operating at a constant switching frequency, a unipolar PWM scheme is used to reduce the input current and the output voltage harmonics. The proposed UPQC contains a series-active and a shunt-active filter. The series-active filter can compensate for the ac source voltage fluctuation. Also, it can be used to regulate the under-voltage and voltage sag situations. On the other hand, the shunt-active filter can compensate for the current harmonic and improve the power factor. Finally, some simulation results are presented for demonstration.

Design and implementation of a three-phase voltage-doubler soft-switching rectifier

A novel four main switches and four auxiliary switches power converter configuration of the three-phase voltage-doubler soft-switching rectifier is proposed in this paper. The reduction in the number of main switches can also increase the reliability because the control circuits and the auxiliary circuits are thereby reduced to two sets. All main switches in the proposed rectifier operate at zero-voltage-switching (ZVS) turn-on. Also, the auxiliary switches operate at zero-current-switching (ZCS) turn-on and turn-off. Furthermore, the proposed rectifier achieves unity power factor, sinusoidal input currents, adjustable output voltage and bidirectional power flow capability. Some experimental results of the proposed soft-switching rectifier are presented for verification.

Analysis and design of a novel single-phase soft-switching active power filter

This study proposes a novel single-phase soft-switching active power filter (SSAPF) using a simple resonance unit. All main switches in the proposed SSAPF operate at zero-voltage-switching (ZVS) turn on, while the auxiliary switches operate at zero-current-switching (ZCS) turn off. The advantages of the proposed power filter include improved efficiency, reduced voltage stresses, and greatly reduced EMI. Moreover, the proposed SSAPF achieves a sinusoidal line current and a near unity power factor. Finally, we present a simple feedforward control to improve the transient performance of the proposed SSAPF. A prototype hardware circuit was constructed, and some experimental results are presented for verification.

Analysis and design of a novel three-phase soft-switching rectifier

A novel power converter configuration of a three-phase soft-switching rectifier comprising four main switches and four auxiliary switches is proposed in this paper. The reduction in number of main switches can also increase the reliability because the control circuits and the auxiliary circuits are thereby reduced to two sets. All main switches in the proposed rectifier operate at zero voltage switching (ZVS) turn-on, while the auxiliary switches operate at zero current switching (ZCS) turn-off. Moreover, the proposed rectifier achieves a near unity power factor, sinusoidal input currents, a regulated output voltage and a bidirectional power flow capability. Finally, a small-signal model is derived and a feed-forward control is presented to achieve almost zero output impedance and zero audio susceptibility. Some experimental results of the proposed soft-switching rectifier, rated 400 W and operated at 40 kHz, are presented for verification.

Analysis and design of a soft-switching single-phase inverter and three-phase modular connection for inverters

This paper presents a zero-voltage-switching (ZVS) pulse-width-modulated (PWM) single-phase inverter and the establishment of a V-connected three-phase inverter using two such single-phase modules. All main switches in the ZVS-PWM inverter operate at ZVS turn-on. The auxiliary switches operate at zero-current-switching (ZCS) turn-off. Since commutations of the main power devices occur with low losses, higher efficiency is achieved. Moreover, two single-phase ZVS-PWM inverter modules are then connected to form a V-connected soft-switching three-phase inverter. Some experimental results are presented for verification.

Analysis and design of a novel single-phase full-bridge soft-switching rectifier

A novel single-phase full-bridge soft switching rectifier (FBSSR) using a new resonance unit is proposed in this paper. All main switches in the proposed soft switching rectifier operate at zero-voltage-switching (ZVS) turn-on and turn-off. Moreover, the auxiliary switches operate at zero-current-switching (ZCS) turn-on and turn-off. Major benefits of this novel rectifier are found in efficiency improvement, and reduced dv/dt. Besides, the proposed rectifier achieves a unity power factor, a sinusoidal input current and a bidirectional power flow capability. A small-signal model is derived and, in addition to the feedback control, an adaptive feed-forward controller is proposed to achieve almost zero output impedance and zero audio susceptibility. Finally, a prototype hardware circuit is constructed, and some experimental results are presented for demonstration.