Ching-Hung Su

A ZVS-PWM Single-Phase Inverter Using a Simple ZVS-PWM Commutation Cell

A new zero-voltage-switching (ZVS) pulsewidth-modulated (PWM) single-phase inverter using a simple ZVS-PWM commutation cell is presented in this paper. Except for the auxiliary switches, all switching devices in the ZVS-PWM single-phase inverter operate at ZVS turn on and turn off. The auxiliary switches operate at zero-current-switching turned-on and turned-off. Besides operating at constant frequency, the proposed inverter has no overvoltage across the switches on the main switch compared to the hard switching inverter counterpart. Auxiliary components rated at very small current are used. The principle of operation, theoretical analysis, and experimental results of the new ZVS-PWM single-phase inverter, rated 1 kW and operated at 40 kHz, are provided in this paper to verify the performance.

A Novel Single-Phase Soft-Switching AC Chopper Without Auxiliary Switches

A single-phase soft-switched series-resonant ac chopper without auxiliary switches is presented. The presented single-phase ac chopper is configured by a series-resonant conversion without cycloconversion and auxiliary switches. The presented single-phase ac chopper is a series resonator with four main switches to configure adaptively the resonant voltage robes. The output sinusoidal voltage is synthesized by a series of sinusoidal amplitude quasi-sinusoidal pulses (QSPs) following the input voltage amplitude. The presented single-phase ac chopper is operated by frequency modulation with a constant-on time control. Waveform syntheses for the output sinusoidal voltage are clearly derived. A typical design example of a 600W single-phase soft-switching ac chopper is examined to assess the system performance. The power efficiency is over 92% when the output power is at maximum output rated power. The total harmonic distortion (THD) when the output power is at maximum output rated power is within 5%.

A Novel ZVS-PWM Single-Phase Inverter Using a Voltage Clamp ZVS Boost DC Link

A novel zero-voltage-switching pulse-width-modulation (ZVS-PWM) single-phase inverter using a voltage clamp ZVS boost dc link is proposed in this paper. The proposed voltage clamp ZVS boost dc link not only provides the switches in the section of conventional PWM buck inverter operate at ZVS, but it has a boost input voltage function and the switches in itself also operate at ZVS. Thus, except for the switch in the section of ZVS-PWM commutation cell, all power semiconductor devices in proposed inverter operate at ZVS turn on and turn off. The switch in the section of ZVS-PWM commutation cell operates at zero-current-switching (ZCS) turn-on and turn-off. Besides operating at constant frequency, the proposed inverter has no voltage stress and current stress on the main switch compared to the hard switching inverter counterpart. Auxiliary components rated at very small current are used. The principle of operation, theoretical analysis, and experimental results of the new ZVS-PWM single-phase inverter, rated 1kW and operated at 80 kHz, are provided in this paper to verify the performance.

A ZVS-PWM voltage-doubler rectifier with high power factor

This paper proposes a new single-phase high power factor rectifier, which features regulation by conventional PWM, soft commutation and instantaneous average line current control. A zero-voltage-switching pulse-width modulation (ZVS-PWM) auxiliary circuit is configured in the presented ZVS-PWM rectifier to perform ZVS in the main switches and the passive switches. Furthermore, soft commutation of the main switch is achieved without additional current stress by the presented ZVS-PWM auxiliary circuit. A significant reduction in the conduction losses is achieved, since the circulating current for the soft switching flows only through the auxiliary circuit and a minimum number of switching devices are involved in the circulating current path, and the proposed rectifier uses a single converter instead of the conventional configuration composed of a four-diode front-end rectifier followed by a boost converter. Seven transition states for describing the behavior of the ZVS-PWM rectifier in one switching period are described. A prototype rated at 1 KW, operating 80 kHz, with an input AC voltage of 220 Vrms and an output voltage 400 Vdc has been implemented in laboratory. An efficiency of 96.7% and power factor over 0.99 has been measured. Analysis, design, and the control circuitry are also presented in this paper.

High-power-factor soft-switched DC power supply system

This paper proposes a dc power supply system to give high power factor and low current distortion on the rectifier side and provide stable dc voltage on the isolated dc/dc converter side. The proposed dc power supply system uses a new zero-voltage-switching (ZVS) strategy to get ZVS function. Besides operating at constant frequency, all semiconductor devices operate at soft switching without additional voltage stress. A significant reduction in the conduction losses is achieved, since the circulating current for the soft-switching flows only through the auxiliary circuit and a minimum number of switching devices are involved in the circulating current path, and the rectifier in the proposed dc power supply system uses a single converter instead of the conventional configuration composed of a four-diode front-end rectifier followed by a boost converter. An average-current-mode control is employed in proposed dc power supply system to detect the transition time and synthesize a suitable low harmonics sinusoidal waveform for the input current. A design example of 1000-W soft-switching single-phase dc power supply system is examined to assess the converter performance.

A Novel ZVS-PWM Single-Phase Inverter Using a New Simple ZVS-PWM Commutation Cell

A new zero-voltage-switching (ZVS) pulsewidth-modulated (PWM) single-phase inverter using a simple ZVS-PWM commutation cell is presented in this paper. Except for the auxiliary switches, all active and passive semiconductor devices in the ZVS-PWM single-phase inverter operate at ZVS turn on and turn off. The auxiliary switches operate at zero-current-switching (ZCS) turned-on and turned-off. Besides operating at constant frequency, the proposed inverter has no overvoltage across the switches on the main switch compared to the hard switching inverter counterpart. Auxiliary components rated at very small current are used. The principle of operation, theoretical analysis, and experimental results of the new ZVS-PWM single-phase inverter, rated 1kW and operated at 40 kHz, are provided in this paper to verify the performance.

A series-resonant single-phase ac chopper

A series-resonant single-phase series-resonant ac chopper is presented. The presented single-phase ac chopper is configured by a series-resonant conversion without cycloconversion and auxiliary switches. The presented single-phase ac chopper is a series resonator with four main switches to configure adaptively the resonant voltage robes. The synthesized sinusoidal waveform (SSW) before output filter is synthesized by a series of sinusoidal amplitude quasi-sinusoidal pulses (QSPs) following the input voltage amplitude. Because the synthesized SSW very closes sinusoidal waveform, the presented single-phase ac chopper can use a simple LC filter to filter the undesired harmonics and get the sinusoidal voltage with low total harmonic distortion (THD). The presented single-phase ac chopper is operated by constant frequency pulse width modulation with control technique. Waveform syntheses for the output sinusoidal voltage are clearly analysed and derived. A typical design example of a 600W series-resonant single-phase ac chopper is examined to assess the system performance. The power efficiency is over 91% when the output power is at maximum output rated power. The total harmonic distortion (THD) when the output power is at maximum output rated power is within 5%.

A novel single-phase soft-switching AC chopper without auxiliary switches

A single-phase soft-switched series-resonant ac chopper without auxiliary switches is presented. The presented single-phase ac chopper is configured by a series-resonant conversion without cycloconversion and auxiliary switches. The presented single-phase ac chopper is a series resonator with four main switches to configure adaptively the resonant voltage robes. The output sinusoidal voltage is synthesized by a series of sinusoidal amplitude quasi-sinusoidal pulses following the input voltage amplitude. The presented single-phase ac chopper is operated by frequency modulation with a constant-on time control. Waveform syntheses for the output sinusoidal voltage are clearly derived. A typical design example of a 600 W single-phase soft-switching ac chopper is examined to assess the system performance. The power efficiency is over 92% when the output power is at maximum output rated power. The total harmonic distortion when the output power is at maximum output rated power is 0.949%.

A Novel Zero-Voltage-Switching Single-Stage High-Power-Factor Electronic Ballast

This paper proposes novel zero-voltage- switching (ZVS) single-stage high-power-factor electronic ballast for fluorescent lamps. In the proposed electronic ballast, all switching devices operate at ZVS turn on and turn off. And the proposed electronic ballast only uses a symmetrical half-bridge topology to procure the functions of a boost power-factor-correction converter and a half-bridge series parallel-loaded inverter. In spite of its simplicity, an excellent performance concerning load and supply is achieved, ensuring a sinusoidal and in phase supply current. The design equations are derived from the analyzed results based on fundamental approximation, and then an easy-to- use design tool is provided accordingly under considerations of filament heating and ignition. A prototype circuit designed for one 40-W fluorescent lamps operating at 40- kHz switching frequency and 110-V line voltage is built and tested to verify the analytical predictions.

High Performance Single-Phase Voltage Regulator with a Simple Circuit Topology

This paper proposes a novel high performance single-stage voltage regulator to give high input power factor and low current distortion on the rectifier side and provide clean and stable ac voltage on the inverter side. The proposed voltage regulator only employs four switches to perform the power factor correction in input side and provide regulation of the output ac voltage magnitude. Thus, its cost is lower than the others. It has a common arm between the rectifier and inverter, and adopts an appropriate switching strategy. A significant reduction in the conduction losses is achieved, since the rectifier in the proposed converter uses a single converter instead of the conventional configuration composed of a four-diode front- end rectifier followed by a boost converter. An average- current-mode control is employed in the rectifier side of proposed converter to synthesize a suitable low harmonics sinusoidal waveform for the input current. The sinusoidal pulse-width modulation (SPWM) control strategy is employed in the inverter of proposed converter to achieve well dynamic regulation. A design example of 1000 W single- phase voltage regulator is examined to assess its performance.