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This paper presents a novel photovoltaic inverter that can not only synchronize a sinusoidal ac output current with a utility line voltage, but also control the power generation of each photovoltaic module in an array. The proposed inverter system is composed of a half-bridge inverter at the utility interface and a novel generation control circuit which compensates for reductions in the output power of the system that are attributable to variations in the generation conditions of respective photovoltaic modules. The generation control circuit allows each photovoltaic module to operate independently at peak capacity, simply by detecting the output power of the system. Furthermore, the generation control circuit attenuates low-frequency ripple voltage, which is caused by the half-bridge inverter, across the photovoltaic modules. Consequently, the output power of system is increased due to the increase in average power generated by the photovoltaic modules. The effectiveness of the proposed inverter system is confirmed experimentally and by means of simulation. Index Terms--Maximum power point tracking control, photovoltaic module, photovoltaic power generation, utility interactive inverters.

A novel type of solid-state ballast, which operates in the megahertz-range frequency, is presented in this paper. A circuit composed of a voltage-source half-bridge inverter, distributed constant line, and parallel LC resonant circuit has been developed for this purpose. The high-intensity discharge (HID) lamp is connected to the output terminal of the inverter through the distributed constant line. Here, since the length of the line is adjusted to 1/4 of the propagation wavelength [Lambda] ([Lambda]/4 condition), the output voltage of the voltage-source inverter can be converted to a current source on the load side. Therefore, the ballast can supply not only high voltage to the HID lamp for initiating discharge, but also stable current to it during discharge condition. The modification of the proposed circuit is also proposed in order to expand the operating frequency without increasing the undesirable harmonic current. The experimental results from a prototype system verify the theoretical procedure. Index Terms - Ballast, distributed constant line, HID lamp, high-frequency inverter.

A novel type of solid-state ballast, which operates in the megahertz-range frequency, is presented in this paper. A circuit composed of a voltage-fed half-bridge inverter, a distributed constant line, and a parallel LC resonant circuit has been developed for this purpose. The high-intensity discharge (HID) lamp is connected to the output terminal of the inverter through the distributed constant line. Here, since the length of the line is adjusted to 1/4 of the propagation wavelength [Lambda], the output voltage of the voltage-fed inverter can be converted to a current source on the load side. Based on the experiment results, the ballast appears to be able to supply not only high voltage, but also constant current for ignition of the HID lamp. The experimental results from a prototype system are used to verify the theoretical procedure. Index Terms - Ballast, distributed constant line, high-intensity discharge lamp, megahertz operation, metal-halide lamp, voltage-fed inverter.

This paper presents a new auxiliary resonant commutated pole inverter that has series-connected batteries as the dc source. This inverter has two main switches and two auxiliary switches, and of all these devices achieve soft switching. The resonant operations are employed only during the commutating intervals; therefore, pulsewidth modulation (PWM) can be applied to the circuit. This circuit has the feature of using two internal voltage points of the dc source. Consequently, the circuit has the advantages of stability, simplicity in control, and high efficiency. The principle of the circuit operation and the experimental results are described in this paper. Index Terms - Auxiliary resonant commutated pole, batteries, pulsewidth modulation, soft switching.

This paper presents a new topology for a pulsewidth modulation (PWM) rectifier which achieves unity power factor on the ac supply side and ripple reduction on the dc output side. The main circuit of this rectifier consists of a conventional PWM rectifier and a pair of additional switches. The switches and PWM rectifier are controlled such that the ripple current on the dc line is reduced, and unity power factor is achieved on the ac line. As a result, this circuit does not require a large dc capacitor or a passive LC resonant circuit. Furthermore, control of the additional switches and PWM rectifier requires only a simple control circuit. The effectiveness of this circuit was confirmed by experiments and analysis. The rectifier is useful for uninterruptible power systems (UPS's) and dc power supplies, especially for cases in which batteries are connected to the dc line. Index Terms - Battery, PWM converter, ripple.

A novel topology of single-phase pulsewidth modulation (PWM) voltage-source rectifier capable of achieving not only a sinusoidal input current, but also a zero-ripple output current, is presented. The rectifier consists of a conventional single-phase PWM voltage-source rectifier, a pair of additional switches, and an inductor. Hence, the proposed rectifier requires neither a large dc capacitor nor a passive L-C resonant circuit. The input current control is achieved by the conventional PWM current control technique. However, dc ripple current reduction control is difficult because one of the switching legs in the dc ripple current reduction circuit is shared with the PWM rectifier circuit. Two control methods, referred to here as the dc C inductor method and the ac inductor method, are proposed for dc ripple reduction, and the characteristics of these control methods are discussed. These control methods are implemented using a microprocessor, and the effectiveness of the circuit is confirmed experimentally. This rectifier has useful applications in uninterruptible power systems and dc power supplies, especially for cases in which the batteries are connected in parallel to the dc line. Index Terms--Battery, pulsewidth modulation rectifier, ripple current.